<![CDATA[Biotechnology Forums - Environmental Biotechnology]]> https://www.biotechnologyforums.com/ Mon, 20 Apr 2026 03:00:55 +0000 MyBB <![CDATA[Yeast extract]]> https://www.biotechnologyforums.com/thread-8319.html Tue, 09 Jan 2018 14:42:21 +0000 Muskan Gupta]]> https://www.biotechnologyforums.com/thread-8319.html <![CDATA[Microbiota succession on soil]]> https://www.biotechnologyforums.com/thread-8167.html Tue, 12 Sep 2017 19:50:27 +0000 Nkabi]]> https://www.biotechnologyforums.com/thread-8167.html <![CDATA[B.tech biotechnology]]> https://www.biotechnologyforums.com/thread-8086.html Sun, 13 Aug 2017 09:07:16 +0000 Harkirat]]> https://www.biotechnologyforums.com/thread-8086.html <![CDATA[Organic mosquito killer haw to make]]> https://www.biotechnologyforums.com/thread-7998.html Fri, 16 Jun 2017 20:57:51 +0000 apurba]]> https://www.biotechnologyforums.com/thread-7998.html <![CDATA[Biotechnology Congress]]> https://www.biotechnologyforums.com/thread-7886.html Wed, 12 Apr 2017 06:03:06 +0000 Kevin Brown]]> https://www.biotechnologyforums.com/thread-7886.html
As the program manager for upcoming conference 17th Euro Biotechnology congress I would like to bring in to your kind notice regarding conference. The 17th Euro Biotechnology Congress which is going to be held at Berlin, Germany during September 25-27, 2017 will feature speakers from multifarious disciplines. Scientists from all over the world are participating in the meet and will present the latest ground-breaking research in all realms of biotechnology.  Focus has been laid on presentations that deal with optimizing industrial processes to increase yield of biotechnology industry and biopharmaceutical products, bio-fuel and bio-energy products. Other than this, research on protein and rDNA technologies including nanotechnology has also been stressed on. I sincerely believe that you will find the conference quite fruitful.
Students interested in attending the international conference in group can avail better discounts on registration.
Best poster and Young research forum is also availed and certification from International organizing committee Members.
For more details follow the link: http://www.biotechnologycongress.com/europe/ 
Feel free to contact us for more details.

Regards
Kevin Brown
Program Manager
Euro Biotechnology
Conference Series]]>
As the program manager for upcoming conference 17th Euro Biotechnology congress I would like to bring in to your kind notice regarding conference. The 17th Euro Biotechnology Congress which is going to be held at Berlin, Germany during September 25-27, 2017 will feature speakers from multifarious disciplines. Scientists from all over the world are participating in the meet and will present the latest ground-breaking research in all realms of biotechnology.  Focus has been laid on presentations that deal with optimizing industrial processes to increase yield of biotechnology industry and biopharmaceutical products, bio-fuel and bio-energy products. Other than this, research on protein and rDNA technologies including nanotechnology has also been stressed on. I sincerely believe that you will find the conference quite fruitful.
Students interested in attending the international conference in group can avail better discounts on registration.
Best poster and Young research forum is also availed and certification from International organizing committee Members.
For more details follow the link: http://www.biotechnologycongress.com/europe/ 
Feel free to contact us for more details.

Regards
Kevin Brown
Program Manager
Euro Biotechnology
Conference Series]]> <![CDATA[Bionomics: Definition, Comprehension and Understanding in detail]]> https://www.biotechnologyforums.com/thread-7738.html Sat, 07 Jan 2017 11:52:56 +0000 stevewoods]]> https://www.biotechnologyforums.com/thread-7738.html
Bionomics

Essence of Bionomics:

In simplest terms, Bionomics refers to the study of a living organism and its relation with its environment.

Bionomics aims at recognizing the traits of the organism concerned and conditions of the environment it thrives in, that act as the proximate causes of its various activities in its niche.

Etymology of Bionomics (origin of the word: Bionomics)

In the modern context, whereas some experts represent Bionomics as a confluence of two greatly different fields: "Biology" and "Economics", coming together to study the economics of life of an organism in its preferred environment, the true and legitimate origin of Bionomics is from the French and Greek words: Bionomique (french word, pertaining to ecology) and Bionomie (Greek word, meaning Ecology).

Significance of Bionomics

Bionomics in its true sense holds significance in studying almost every living organism and its relation with environment (including plants , marine life, life in space etc),  but, Bionomics as a field became more popular in the context of studying 'parasitic / vector borne diseases' (especially those pertaining to pests/ insects). Following are the key focal points of Bionomics in context of vector borne diseases:

1. Establishing the relation between disease epidemiology and the ecological status of its vector.
2. Using this relationship in controlling the progression/ spread of the vector.

The aforesaid relation is determined by thoroughly studying the following:

a). Life Cycle of the vector
b). Optimal living conditions for various stages of life of vector (i.e what promotes or disrupts the growth or reproduction of the vector).
c). Feeding patterns and periods of activity (nocturnal or diurnal).
d).  Information on characteristics of specific larval habitats
e). Study of ecological diversity of the vector species coupled with their behavioural plasticity.
f). Interaction patterns  of vector with other organisms (and the causes of those interactions).


Some references:
  • Developing Global Maps of the Dominant Anopheles Vectors of Human Malaria Hay et al., 2010
  • Vector bionomics in the epidemiology and control of malaria. Part I. Zahar AR, 1984
  • Bionomics, taxonomy, and distribution of the major malaria vector taxa of Anopheles subgenus Cellia in Southeast Asia: an updated review. Manguin et al., 2008
More details to be added | Stay tuned..
]]>
Bionomics

Essence of Bionomics:

In simplest terms, Bionomics refers to the study of a living organism and its relation with its environment.

Bionomics aims at recognizing the traits of the organism concerned and conditions of the environment it thrives in, that act as the proximate causes of its various activities in its niche.

Etymology of Bionomics (origin of the word: Bionomics)

In the modern context, whereas some experts represent Bionomics as a confluence of two greatly different fields: "Biology" and "Economics", coming together to study the economics of life of an organism in its preferred environment, the true and legitimate origin of Bionomics is from the French and Greek words: Bionomique (french word, pertaining to ecology) and Bionomie (Greek word, meaning Ecology).

Significance of Bionomics

Bionomics in its true sense holds significance in studying almost every living organism and its relation with environment (including plants , marine life, life in space etc),  but, Bionomics as a field became more popular in the context of studying 'parasitic / vector borne diseases' (especially those pertaining to pests/ insects). Following are the key focal points of Bionomics in context of vector borne diseases:

1. Establishing the relation between disease epidemiology and the ecological status of its vector.
2. Using this relationship in controlling the progression/ spread of the vector.

The aforesaid relation is determined by thoroughly studying the following:

a). Life Cycle of the vector
b). Optimal living conditions for various stages of life of vector (i.e what promotes or disrupts the growth or reproduction of the vector).
c). Feeding patterns and periods of activity (nocturnal or diurnal).
d).  Information on characteristics of specific larval habitats
e). Study of ecological diversity of the vector species coupled with their behavioural plasticity.
f). Interaction patterns  of vector with other organisms (and the causes of those interactions).


Some references:
  • Developing Global Maps of the Dominant Anopheles Vectors of Human Malaria Hay et al., 2010
  • Vector bionomics in the epidemiology and control of malaria. Part I. Zahar AR, 1984
  • Bionomics, taxonomy, and distribution of the major malaria vector taxa of Anopheles subgenus Cellia in Southeast Asia: an updated review. Manguin et al., 2008
More details to be added | Stay tuned..
]]> <![CDATA[What are the important microbes that useful in bioremediation process!??]]> https://www.biotechnologyforums.com/thread-7706.html Tue, 20 Dec 2016 15:29:01 +0000 niharuddin]]> https://www.biotechnologyforums.com/thread-7706.html <![CDATA[All Things Cyanobacteria]]> https://www.biotechnologyforums.com/thread-3027.html Sun, 09 Feb 2014 20:52:11 +0000 philpense]]> https://www.biotechnologyforums.com/thread-3027.html Specifically, I have interest in the marine cyanobacteria that produce oxygen, ethylene and both. Seeking the top producers and would like to know which members cultivate these
Some of the culture labs did not answer virtually any of my emailed queries.

Guidance sought]]> Specifically, I have interest in the marine cyanobacteria that produce oxygen, ethylene and both. Seeking the top producers and would like to know which members cultivate these
Some of the culture labs did not answer virtually any of my emailed queries.

Guidance sought]]> <![CDATA[Complication of Animal Genomes during Evolution Slowed Down after Cambrian Explosion]]> https://www.biotechnologyforums.com/thread-2509.html Fri, 04 Oct 2013 17:04:32 +0000 Sergey Klykov]]> https://www.biotechnologyforums.com/thread-2509.html Skladnev D. A., Klykov S. P., Kurakov V. V. Complication of Animal Genomes in the Course of the Evolution Slowed Down after the Cambrian Explosion. Evolution: Development within Big History, Evolutionary and World-System Paradigms. Yearbook / Ed. by L. E. Grinin and A. V. Korotayev. Volgograd: Uchitel, 2013. Pp. 249–256.

Abstract
For the first time, the growth rate of minimal animal genome size is shown to
slow down in the course of evolution from prokaryotic forms to mammals after
the Cambrian explosion. There is proposed an original mathematical model
which takes into account a multiphase character of development and importance
of multidirectional trends in the evolution. The authors explain from the
biological point the exponential change of minimal genome size in the beginning
of the evolutionary process, slowing down after the period of the Cambrian
explosion as well as reveal certain parameters of the evolutionary processes
as a result of the model application. According to the proposed model, the
S-shaped curve with distinct inflexion point adequately describes the increase
of minimal genome size.
Keywords: evolution equations, mathematical modeling, genome size, Cambrian
explosion.

Internet link will be provided through 2 weeks, roughly. You can download the PDF right now from my page:
http://www.linkedin.com/profile/view?id=...ab_profile

See also:
http://www.biotechnologyforums.com/thread-1809.html
]]> Skladnev D. A., Klykov S. P., Kurakov V. V. Complication of Animal Genomes in the Course of the Evolution Slowed Down after the Cambrian Explosion. Evolution: Development within Big History, Evolutionary and World-System Paradigms. Yearbook / Ed. by L. E. Grinin and A. V. Korotayev. Volgograd: Uchitel, 2013. Pp. 249–256.

Abstract
For the first time, the growth rate of minimal animal genome size is shown to
slow down in the course of evolution from prokaryotic forms to mammals after
the Cambrian explosion. There is proposed an original mathematical model
which takes into account a multiphase character of development and importance
of multidirectional trends in the evolution. The authors explain from the
biological point the exponential change of minimal genome size in the beginning
of the evolutionary process, slowing down after the period of the Cambrian
explosion as well as reveal certain parameters of the evolutionary processes
as a result of the model application. According to the proposed model, the
S-shaped curve with distinct inflexion point adequately describes the increase
of minimal genome size.
Keywords: evolution equations, mathematical modeling, genome size, Cambrian
explosion.

Internet link will be provided through 2 weeks, roughly. You can download the PDF right now from my page:
http://www.linkedin.com/profile/view?id=...ab_profile

See also:
http://www.biotechnologyforums.com/thread-1809.html
]]> <![CDATA[Use of Algae through different approaches]]> https://www.biotechnologyforums.com/thread-2262.html Wed, 29 May 2013 07:54:25 +0000 vppbiotech]]> https://www.biotechnologyforums.com/thread-2262.html INTRODUCTION:

It seems probable that growth in human population, future climate change effects on freshwater resources, which are already stressed in some regions and eventual shortages of unutilized arable land will encourage the exploitation of microalgae based production systems for both food and fuel. Claims that the ability to utilise non-arable land and waste water resources with few competing uses make algal biofuel production systems superior to biofuels based on terrestrial biomass has created great interest in governments, NGOs, the private sector and the research community. Current initiatives clearly indicate this interest at all levels of government and the in private sector in the development of algal biofuels technologies and enterprises. Microalgae are one of the most important bioresources that are currently receiving a lot of attention due to a multiplicity of reasons. The world is faced with energy challenges in the near future and it is reported that fossil fuel reserves will be depleted in half a century . This will be an unprecedented vicissitude that will impact negatively on all anthropogenic activities most importantly agriculture, industry and commerce. With this in mind, it is crucial to explore renewable and cost-effective sources of energy for the future. It has been estimated that biomass could provide about 25% of global energy requirements and can also be a source of valuable chemicals, pharmaceuticals and food additives.

In addition, the growing of urban population poses a serious threat to the environment due to the release of copious amounts of domestic municipal wastewater. The use of microalgae is desirable since they are able to serve a many role of bioremediation of wastewater, generating biomass for biofuel production with concomitant carbon dioxide sequestration. In addition, wastewater remediation by microalgae is an eco-friendly process with no secondary pollution as long as the biomass produced is reused and allows efficient nutrient recycling. As the demand for energy continues to increase globally, fossil fuel usage will likewise continue to rise. There is still a plentiful supply of fossil fuels at reasonably low cost, although this is likely to change in the future, but more critically a rising use of fossil fuels is unlikely to be sustainable in the longer term principally due to the attributed increase in greenhouse gas (GHG) emissions from using these fuels and the environmental impact of these emissions on global warming. There is therefore significant interest in identifying alternative renewable sources of fuel that are potentially carbon neutral. Biofuels derived from the cultivation of algae have therefore been proposed as an alternative approach that does not impact on agriculture. Microalgae cultivation using sunlight energy can be carried out in open or covered ponds or closed photobioreactors, based on tubular, flat plate or other designs. Microalgae production in closed photobioreactors is highly expensive. Closed systems are much more expensive than ponds. However, the closed systems require much less light and agricultural land to grow the algae. In order to have an optimal yield, these algae need to have CO2 in large quantities in the basins or bioreactors where they grow. Thus, the basins and bioreactors need to be coupled with traditional thermal power centers producing electricity which produce CO2 at an average tenor of 13% of total flue gas emissions. The CO2 is put in the basins and is assimilated by the algae. It is thus a technology which recycles CO2 while also treating used water. Use of biodiesel from oilgae is a promising alternative to solve air pollution problems. Algae-based technologies could provide a key tool for reducing greenhouse gas emissions from coal-fired power plants and other carbon intensive industrial processes. To achieve environmental and economic sustainability, fuel production processes are required that are not only renewable, but also capable of sequestering atmospheric carbon dioxide (CO2). Second generation microalgal systems have the advantage that they can produce a wide range of feedstocks for the production of biofuels. Biodiesel is currently produced from oil synthesized by conventional fuel crops that harvest the sun’s energy and store it as chemical energy. This presents a route for renewable and carbon-neutral fuel production. However, current supplies from oil crops and animal fats account for only approximately 0.3% of the current demand for transport fuels. In 2008 the world production of biodiesel fuel was about 13.9 million ton [48-52]. In addition, these photosynthetic microorganisms are useful in bioremediation applications. The advantages of using microalgae for biodiesel production cannot be overemphasized. Biodiesel can be generated from 0306-2619/$ crops such as sugar cane, soybean, canola, rapeseed, maize, olive oil, non-edible jatropha, inter alia. However the use of food crops for biofuels has generated much debate involving food security concerns. The main advantages of using microalgae as a source of biomass for biodiesel production are: high growth rates and short generation times, minimal land requirements, high lipid content, use of wastewater stream as nutrient feed with no need for chemicals such as herbicides and pesticides.

II. MULTIPLE ROLES OF MICROALGAE
There is several utilization of algae or microalgae by which we can sort out the environment problems like; the major problem of global warming is CO2 in the atmosphere which creates green house effects, so for the growth of microalgae the utilization of CO2 is very essential, and to generates around 1 kg algal biomass requires 1kg of CO2 which is better to sort out this problem, it can be reduce many heavy or toxic metals form waste water and this process called Phycoremediation, It can be use as biofuel to reduce the effect of our conventional fuel which is going to be finish day by day because algae have potential to produce biofuel in the form of lipid which id further processed by transesterification process get the biodiesel which has the properties same as the our conventional diesel and it can be use for the many cosmetics, food and many use in the field of pharmaceuticals.


A. Phycoremediation
Phycoremediation may be defined in a broad sense as the use of macroalgae or microalgae for the removal or biotransformation of pollutants, including nutrients and xenobiotics from wastewater and CO2 from waste air with concomitant biomass propagation. There are numerous processes of treating water, industrial effluents and solid wastes using microalgae aerobically as well as anaerobically. Remediation is generally subject to an array of regulatory requirements, and also can be based on assessments of human health and ecological risks where no legislative standards exist. Recent studies have shown that microalgae can indeed support the aerobic degradation of various hazardous contaminants. The mechanisms involved in microalgae nutrient removal from industrial wastewaters are similar to that from domestic wastewaters treatment. Phycoremediation comprises several applications: (i) nutrient removal from municipal wastewater and effluents rich in organic matter; (ii) nutrient and xenobiotic compounds removal with the aid of algae-based biosorbents; (iii) treatment of acidic and metal wastewaters; (iv) CO2 sequestration; (v) transformation and degradation of xenobiotics; and (vi) detection of toxic compounds with the aid of algae-based biosensors. Nutrient removal with the aid of microalgae compares very favourably to other conventional technologies.

The growth of microalgae is indicative of water pollution since they respond typically too many ions and toxins. Blue-green algae are ideally suited to play a dual role of treating wastewater in the process of effective utilization of different constituents essential for growth leading to enhanced biomass production. The release of free oxygen is of major significance in organically enriched wastewater, promoting aerobic degradation processes by and other microorganisms. Secondly the role of microalgae is the accumulation and conversion of wastewater nutrients to biomass and lipids.

The capability of microalgae to degrade hazardous organic pollutants is well known. Chlorella, Ankistrodesmus and Scenedesmus species have been already successfully used for the treatment of olive oil, mill wastewaters and paper industry wastewaters. One way to investigate the capability of algae to biodegrade organic pollutants in municipal waste is to encourage the cells to grow in the presence of the pollutants and findings showed that both cyanobacteria (blue-green algae) and eukaryotic microalgae were capable of biotransforming naphthalene to four major metabolites, 1-naphthol, 4-hydrox-4-tetralone, cis-naphthalene dihydrodiol and trans-naphthalene dihydrodiol at concentrations which were non-toxic. The biomass resulting from the treatment of wastewaters can be easily converted into added value products. Depending by the species used for this purpose, the resulting biomass can be applied for different aims, including the use as additives for animal feed, the extraction of added value products like carotenoids or other bio-molecules or the production of biofuel.

The mass production of algae has historically been for use as a food supplement or wastewater treatment. The technology for production of biomass from wastewater has been present since the 1950s. Microalgae are efficient in the removal of nutrients from wastewater. Thus many microalgal species proliferate in wastewater due to the abundance of carbon, nitrogen and phosphorus that act as nutrients for the algae. Unicellular algae have shown great efficiency in the uptake of nutrients and have been found to show dominance in oxidation ponds. Application of using wastewater for the production of biomass however, occurs only on a minor scale and generally in the form of waste stabilization ponds or high rate algal ponds for the treatment of wastewater. Production of biomass from wastewater requires, similar production of biomass on artificial media, depends on a number of factors. However factors of heavy metal contamination require greater attention than in conventional production from media. Park et al. has recorded the following to be desirable attributes of microalgal species for use in High rate algal ponds (HRAPs), (1) High biomass productivity when grown on wastewater, (2) tolerances to seasonal and diurnal variation in outdoor conditions, (3) form aggregates to enhance ease of harvesting, (4) accumulation of high amounts of lipid or other valuable products. This suggests the potential of lowering the cost of algal biofuels production, which is currently not economically feasible.

B. Wastewater treatment methods
An understanding of the nature of wastewater is essential in the design and operation of treatment processes. Disposing of liquid and solid waste in rivers, streams, lakes and oceans seemed convenient for mankind. The quantities of wastewater at any point may ‘‘over load’’ the bio-system disrupting the natural recycling processes such as photosynthesis, respiration, nitrogen fixation, evaporation and precipitation. Wastewater treatment is an important initiative which has to be taken more seriously for the betterment of society and our future. Wastewater treatment is a process, where contaminants are removed from wastewater including domestic wastewater, to produce waste stream or solid waste suitable for discharge or reuse. Domestic wastewater is a combination of water and other wastes originating from homes, commercial and industrial facilities, and institutions. Untreated wastewater generally contains high levels of organic material, numerous pathogenic microorganisms, as well as nutrients and toxic compounds. Disposal of municipal solid wastes (MSW) in sanitary landfills is usually associated with soil, surface water and groundwater contamination when the landfill is not properly constructed. It thus entails environmental and health hazards, consequently, must immediately be conveyed away from its generation source(s) and treated appropriately before final disposal. The ultimate goal of wastewater management is the protection of the environment in a manner commensurate with public health and socio-economic concerns. Biological treatment is an important aspect of industrial and municipal wastewater treatment and reuse processes. Wastewater treatment methods are broadly classified into three categories; there are physical, chemical and biological. Among the first treatment methods used were physical unit operations, in which mechanical forces are applied to remove contaminants. Today, they still form the basis of most process flow systems for wastewater treatment. Chemical processes used in wastewater treatment are designed to bring about some form of change by means of chemical reactions. They are always used in conjunction with physical unit operations and biological processes. In general, chemical unit processes have an inherent disadvantage compared to physical operations in that they are additive processes, since there is usually a net increase in the dissolved constituents of the wastewater. This can be a significant factor if the wastewater is to be reused.

It has been appreciated for some years now that microalgae can be potentially utilized for low cost and environmentally friendly wastewater treatment compared to other more commonly used treatment processes. The selection of microorganisms for use as alternative fuel sources requires a sustainable growth medium such as domestic wastewater streams. The majority of wastewaters contain very high concentrations of nutrients, particularly total N and total P concentration as well as toxic metals, so there is no requirement for costly chemical-based treatments. According to de la Noue et al. the concentration of total N and P can be found at values of 10–100 mg L-1 in municipal wastewater and >1000 mg L-1 in agricultural effluent. Microalgae have potential to treat wastewater by efficiently accumulating nutrients and metals from the wastewater. Sustainable low cost wastewater treatment has been strongly proven by using microalgae. Microalgae grown on wastewater for energy production have been proposed for a long time. However, in recent years, microalgae seem to be a favorite candidate for this purpose, due to their ease of cultivation and the favourable possibility of their use as an alternative biomass for bioenergy production. Increase in global warming, depletion of fossil fuel and the need for mitigation of green-house gas (GHS) emissions; make exploration of the feasibility of biological wastewater treatment .


C. Algal biofuels
Algae, particularly green unicellular microalgae have been proposed for a long time as a potential renewable fuel source. Microalgae have the potential to generate significant quantities of biomass and oil suitable for conversion to biodiesel. Microalgae have been estimated to have higher biomass productivity than plant crops in terms of land area required for cultivation, are predicted to have lower cost per yield, and have the potential to reduce GHG emissions through the replacement of fossil fuels.

As with plant-derived feedstocks, algal feedstocks can be utilized directly or processed into liquid fuels and gas by a variety of biochemical conversion or thermochemical conversion processes. Dried algal biomass may be used to generate energy by direct combustion but this is probably the least attractive use for algal biomass. Thermochemical conversion methods include gasification, pyrolysis, hydrogenation and liquefaction of the algal biomass to yield gas- or oil-based biofuels. Biochemical conversion processes include fermentation and anaerobic digestion of the biomass to yield bioethanol or methane. In addition, hydrogen can be produced from algae by bio- photolysis. Finally, lipids, principally triacylglycerol lipids can be separated and isolated from harvested microalgae and then converted to biodiesel by transesterification.

The potential for sustainable biofuel production One of the attractions of microalgae as a biofuel feedstock is that they can be effectively grown in conditions which require minimal freshwater input unlike many plant-based biofuel crops, and utilize land which is otherwise non-productive to plant crops, thus making the process potentially sustainable with regard to preserving freshwater resources. For example, microalgae could be cultivated near the sea to utilize saline or brackish water. There has therefore been significant interest in the growth of microalgae for biofuels under saline conditions. However, another potentially sustainable growth medium for algal feedstock is wastewater. It has been appreciated for some years now that microalgae can be potentially utilized for low-cost and environmentally friendly wastewater treatment compared to other more commonly used treatment processes.

D. Biodiesel from oilgae
Biodiesel is a biofuel commonly consisting of methyl esters that are derived from organic oils, plant or animal, through the process of transesterification.

An excess of methanol is used to force the reaction to favor the right side of the equation. The excess methanol is later recovered and reused. Biodiesel has received much attention in recent years. Biodiesel is the best candidate for diesel fuels in diesel engines. Biodiesel burns similarly to petroleum diesel as it concerns regulated pollutants. On the other hand biodiesel probably has better efficiency than gasoline. Biodiesel fuel has better properties than petro-diesel fuel; it is renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics. Typical raw materials of biodiesel are rapeseed oil, soybean oil, sunflower oil and palm oil. Beef and sheep tallow and chicken fat from animal sources and cooking oil are also sources of raw materials. Commonly accepted biodiesel raw materials include the oils from soy, canola, corn, rapeseed, and palm. New plant oils that are under consideration include mustard seed, peanut, sunflower, and cotton seed. The most commonly considered animal fats include those derived from poultry, beef, and pork. Serious problems face the world food supply today. Food versus fuel is the dilemma regarding the risk of diverting farmland or crops for liquid biofuels production in detriment of the food supply on a global scale. Biofuel production has increased in recent years.

E. Biofixation of carbon dioxide by microalgae
Biofixation of CO2 by microalgae mass cultures represents an advanced, climate friendly biological process that enables the direct utilization of fossil CO2 streams produced from concentrated sources. Mitigation of GHG emissions would result from the conversion of the algal biomass to renewable biofuels [56,45,52 and 69]. Fossil-fuel-fired power plants contribute approximately one third of the total human-caused emissions of CO2. Fossil fuels will remain the mainstay of energy production well into the 21st century. However, increased concentrations of CO2 due to carbon emissions are expected unless energy systems reduce the carbon emissions to the atmosphere. To stabilize and ultimately reduce concentrations of the CO2 gas, it will be necessary to employ carbon sequestration – carbon capture, separation and storage or reuse. Carbon sequestration, along with reduced carbon content of fuels and improved efficiency of energy production and use, must play major roles if the nation is to enjoy the economic and energy security benefits, which fossil fuels brings to the energy mix. The availability of a carbon dioxide fixation technology would serve as insurance in case global warming causes severe restrictions on carbon dioxide emissions. Integrated processes in wastewater treatment and aquaculture were indicated as near-term applications of this technology. Microalgae applications in greenhouse gas mitigation could come through the development of wastewater treatment and aquaculture processes that combine their waste treatment features with reduction in greenhouse gas emissions and biofuels production. The greatest potential for microalgae biofixation processes is in developing countries, which should be included in any future development of this technology. The ultimate objective of microalgae biofixation of CO2 is to operate large-scale systems that are able to convert a significant fraction of the CO2 outputs from a power plant into biofuels. Biofixation of CO2 using photosynthetic organisms has been looked at as a way to stop or slow down the effects of global warming.
]]> INTRODUCTION:

It seems probable that growth in human population, future climate change effects on freshwater resources, which are already stressed in some regions and eventual shortages of unutilized arable land will encourage the exploitation of microalgae based production systems for both food and fuel. Claims that the ability to utilise non-arable land and waste water resources with few competing uses make algal biofuel production systems superior to biofuels based on terrestrial biomass has created great interest in governments, NGOs, the private sector and the research community. Current initiatives clearly indicate this interest at all levels of government and the in private sector in the development of algal biofuels technologies and enterprises. Microalgae are one of the most important bioresources that are currently receiving a lot of attention due to a multiplicity of reasons. The world is faced with energy challenges in the near future and it is reported that fossil fuel reserves will be depleted in half a century . This will be an unprecedented vicissitude that will impact negatively on all anthropogenic activities most importantly agriculture, industry and commerce. With this in mind, it is crucial to explore renewable and cost-effective sources of energy for the future. It has been estimated that biomass could provide about 25% of global energy requirements and can also be a source of valuable chemicals, pharmaceuticals and food additives.

In addition, the growing of urban population poses a serious threat to the environment due to the release of copious amounts of domestic municipal wastewater. The use of microalgae is desirable since they are able to serve a many role of bioremediation of wastewater, generating biomass for biofuel production with concomitant carbon dioxide sequestration. In addition, wastewater remediation by microalgae is an eco-friendly process with no secondary pollution as long as the biomass produced is reused and allows efficient nutrient recycling. As the demand for energy continues to increase globally, fossil fuel usage will likewise continue to rise. There is still a plentiful supply of fossil fuels at reasonably low cost, although this is likely to change in the future, but more critically a rising use of fossil fuels is unlikely to be sustainable in the longer term principally due to the attributed increase in greenhouse gas (GHG) emissions from using these fuels and the environmental impact of these emissions on global warming. There is therefore significant interest in identifying alternative renewable sources of fuel that are potentially carbon neutral. Biofuels derived from the cultivation of algae have therefore been proposed as an alternative approach that does not impact on agriculture. Microalgae cultivation using sunlight energy can be carried out in open or covered ponds or closed photobioreactors, based on tubular, flat plate or other designs. Microalgae production in closed photobioreactors is highly expensive. Closed systems are much more expensive than ponds. However, the closed systems require much less light and agricultural land to grow the algae. In order to have an optimal yield, these algae need to have CO2 in large quantities in the basins or bioreactors where they grow. Thus, the basins and bioreactors need to be coupled with traditional thermal power centers producing electricity which produce CO2 at an average tenor of 13% of total flue gas emissions. The CO2 is put in the basins and is assimilated by the algae. It is thus a technology which recycles CO2 while also treating used water. Use of biodiesel from oilgae is a promising alternative to solve air pollution problems. Algae-based technologies could provide a key tool for reducing greenhouse gas emissions from coal-fired power plants and other carbon intensive industrial processes. To achieve environmental and economic sustainability, fuel production processes are required that are not only renewable, but also capable of sequestering atmospheric carbon dioxide (CO2). Second generation microalgal systems have the advantage that they can produce a wide range of feedstocks for the production of biofuels. Biodiesel is currently produced from oil synthesized by conventional fuel crops that harvest the sun’s energy and store it as chemical energy. This presents a route for renewable and carbon-neutral fuel production. However, current supplies from oil crops and animal fats account for only approximately 0.3% of the current demand for transport fuels. In 2008 the world production of biodiesel fuel was about 13.9 million ton [48-52]. In addition, these photosynthetic microorganisms are useful in bioremediation applications. The advantages of using microalgae for biodiesel production cannot be overemphasized. Biodiesel can be generated from 0306-2619/$ crops such as sugar cane, soybean, canola, rapeseed, maize, olive oil, non-edible jatropha, inter alia. However the use of food crops for biofuels has generated much debate involving food security concerns. The main advantages of using microalgae as a source of biomass for biodiesel production are: high growth rates and short generation times, minimal land requirements, high lipid content, use of wastewater stream as nutrient feed with no need for chemicals such as herbicides and pesticides.

II. MULTIPLE ROLES OF MICROALGAE
There is several utilization of algae or microalgae by which we can sort out the environment problems like; the major problem of global warming is CO2 in the atmosphere which creates green house effects, so for the growth of microalgae the utilization of CO2 is very essential, and to generates around 1 kg algal biomass requires 1kg of CO2 which is better to sort out this problem, it can be reduce many heavy or toxic metals form waste water and this process called Phycoremediation, It can be use as biofuel to reduce the effect of our conventional fuel which is going to be finish day by day because algae have potential to produce biofuel in the form of lipid which id further processed by transesterification process get the biodiesel which has the properties same as the our conventional diesel and it can be use for the many cosmetics, food and many use in the field of pharmaceuticals.


A. Phycoremediation
Phycoremediation may be defined in a broad sense as the use of macroalgae or microalgae for the removal or biotransformation of pollutants, including nutrients and xenobiotics from wastewater and CO2 from waste air with concomitant biomass propagation. There are numerous processes of treating water, industrial effluents and solid wastes using microalgae aerobically as well as anaerobically. Remediation is generally subject to an array of regulatory requirements, and also can be based on assessments of human health and ecological risks where no legislative standards exist. Recent studies have shown that microalgae can indeed support the aerobic degradation of various hazardous contaminants. The mechanisms involved in microalgae nutrient removal from industrial wastewaters are similar to that from domestic wastewaters treatment. Phycoremediation comprises several applications: (i) nutrient removal from municipal wastewater and effluents rich in organic matter; (ii) nutrient and xenobiotic compounds removal with the aid of algae-based biosorbents; (iii) treatment of acidic and metal wastewaters; (iv) CO2 sequestration; (v) transformation and degradation of xenobiotics; and (vi) detection of toxic compounds with the aid of algae-based biosensors. Nutrient removal with the aid of microalgae compares very favourably to other conventional technologies.

The growth of microalgae is indicative of water pollution since they respond typically too many ions and toxins. Blue-green algae are ideally suited to play a dual role of treating wastewater in the process of effective utilization of different constituents essential for growth leading to enhanced biomass production. The release of free oxygen is of major significance in organically enriched wastewater, promoting aerobic degradation processes by and other microorganisms. Secondly the role of microalgae is the accumulation and conversion of wastewater nutrients to biomass and lipids.

The capability of microalgae to degrade hazardous organic pollutants is well known. Chlorella, Ankistrodesmus and Scenedesmus species have been already successfully used for the treatment of olive oil, mill wastewaters and paper industry wastewaters. One way to investigate the capability of algae to biodegrade organic pollutants in municipal waste is to encourage the cells to grow in the presence of the pollutants and findings showed that both cyanobacteria (blue-green algae) and eukaryotic microalgae were capable of biotransforming naphthalene to four major metabolites, 1-naphthol, 4-hydrox-4-tetralone, cis-naphthalene dihydrodiol and trans-naphthalene dihydrodiol at concentrations which were non-toxic. The biomass resulting from the treatment of wastewaters can be easily converted into added value products. Depending by the species used for this purpose, the resulting biomass can be applied for different aims, including the use as additives for animal feed, the extraction of added value products like carotenoids or other bio-molecules or the production of biofuel.

The mass production of algae has historically been for use as a food supplement or wastewater treatment. The technology for production of biomass from wastewater has been present since the 1950s. Microalgae are efficient in the removal of nutrients from wastewater. Thus many microalgal species proliferate in wastewater due to the abundance of carbon, nitrogen and phosphorus that act as nutrients for the algae. Unicellular algae have shown great efficiency in the uptake of nutrients and have been found to show dominance in oxidation ponds. Application of using wastewater for the production of biomass however, occurs only on a minor scale and generally in the form of waste stabilization ponds or high rate algal ponds for the treatment of wastewater. Production of biomass from wastewater requires, similar production of biomass on artificial media, depends on a number of factors. However factors of heavy metal contamination require greater attention than in conventional production from media. Park et al. has recorded the following to be desirable attributes of microalgal species for use in High rate algal ponds (HRAPs), (1) High biomass productivity when grown on wastewater, (2) tolerances to seasonal and diurnal variation in outdoor conditions, (3) form aggregates to enhance ease of harvesting, (4) accumulation of high amounts of lipid or other valuable products. This suggests the potential of lowering the cost of algal biofuels production, which is currently not economically feasible.

B. Wastewater treatment methods
An understanding of the nature of wastewater is essential in the design and operation of treatment processes. Disposing of liquid and solid waste in rivers, streams, lakes and oceans seemed convenient for mankind. The quantities of wastewater at any point may ‘‘over load’’ the bio-system disrupting the natural recycling processes such as photosynthesis, respiration, nitrogen fixation, evaporation and precipitation. Wastewater treatment is an important initiative which has to be taken more seriously for the betterment of society and our future. Wastewater treatment is a process, where contaminants are removed from wastewater including domestic wastewater, to produce waste stream or solid waste suitable for discharge or reuse. Domestic wastewater is a combination of water and other wastes originating from homes, commercial and industrial facilities, and institutions. Untreated wastewater generally contains high levels of organic material, numerous pathogenic microorganisms, as well as nutrients and toxic compounds. Disposal of municipal solid wastes (MSW) in sanitary landfills is usually associated with soil, surface water and groundwater contamination when the landfill is not properly constructed. It thus entails environmental and health hazards, consequently, must immediately be conveyed away from its generation source(s) and treated appropriately before final disposal. The ultimate goal of wastewater management is the protection of the environment in a manner commensurate with public health and socio-economic concerns. Biological treatment is an important aspect of industrial and municipal wastewater treatment and reuse processes. Wastewater treatment methods are broadly classified into three categories; there are physical, chemical and biological. Among the first treatment methods used were physical unit operations, in which mechanical forces are applied to remove contaminants. Today, they still form the basis of most process flow systems for wastewater treatment. Chemical processes used in wastewater treatment are designed to bring about some form of change by means of chemical reactions. They are always used in conjunction with physical unit operations and biological processes. In general, chemical unit processes have an inherent disadvantage compared to physical operations in that they are additive processes, since there is usually a net increase in the dissolved constituents of the wastewater. This can be a significant factor if the wastewater is to be reused.

It has been appreciated for some years now that microalgae can be potentially utilized for low cost and environmentally friendly wastewater treatment compared to other more commonly used treatment processes. The selection of microorganisms for use as alternative fuel sources requires a sustainable growth medium such as domestic wastewater streams. The majority of wastewaters contain very high concentrations of nutrients, particularly total N and total P concentration as well as toxic metals, so there is no requirement for costly chemical-based treatments. According to de la Noue et al. the concentration of total N and P can be found at values of 10–100 mg L-1 in municipal wastewater and >1000 mg L-1 in agricultural effluent. Microalgae have potential to treat wastewater by efficiently accumulating nutrients and metals from the wastewater. Sustainable low cost wastewater treatment has been strongly proven by using microalgae. Microalgae grown on wastewater for energy production have been proposed for a long time. However, in recent years, microalgae seem to be a favorite candidate for this purpose, due to their ease of cultivation and the favourable possibility of their use as an alternative biomass for bioenergy production. Increase in global warming, depletion of fossil fuel and the need for mitigation of green-house gas (GHS) emissions; make exploration of the feasibility of biological wastewater treatment .


C. Algal biofuels
Algae, particularly green unicellular microalgae have been proposed for a long time as a potential renewable fuel source. Microalgae have the potential to generate significant quantities of biomass and oil suitable for conversion to biodiesel. Microalgae have been estimated to have higher biomass productivity than plant crops in terms of land area required for cultivation, are predicted to have lower cost per yield, and have the potential to reduce GHG emissions through the replacement of fossil fuels.

As with plant-derived feedstocks, algal feedstocks can be utilized directly or processed into liquid fuels and gas by a variety of biochemical conversion or thermochemical conversion processes. Dried algal biomass may be used to generate energy by direct combustion but this is probably the least attractive use for algal biomass. Thermochemical conversion methods include gasification, pyrolysis, hydrogenation and liquefaction of the algal biomass to yield gas- or oil-based biofuels. Biochemical conversion processes include fermentation and anaerobic digestion of the biomass to yield bioethanol or methane. In addition, hydrogen can be produced from algae by bio- photolysis. Finally, lipids, principally triacylglycerol lipids can be separated and isolated from harvested microalgae and then converted to biodiesel by transesterification.

The potential for sustainable biofuel production One of the attractions of microalgae as a biofuel feedstock is that they can be effectively grown in conditions which require minimal freshwater input unlike many plant-based biofuel crops, and utilize land which is otherwise non-productive to plant crops, thus making the process potentially sustainable with regard to preserving freshwater resources. For example, microalgae could be cultivated near the sea to utilize saline or brackish water. There has therefore been significant interest in the growth of microalgae for biofuels under saline conditions. However, another potentially sustainable growth medium for algal feedstock is wastewater. It has been appreciated for some years now that microalgae can be potentially utilized for low-cost and environmentally friendly wastewater treatment compared to other more commonly used treatment processes.

D. Biodiesel from oilgae
Biodiesel is a biofuel commonly consisting of methyl esters that are derived from organic oils, plant or animal, through the process of transesterification.

An excess of methanol is used to force the reaction to favor the right side of the equation. The excess methanol is later recovered and reused. Biodiesel has received much attention in recent years. Biodiesel is the best candidate for diesel fuels in diesel engines. Biodiesel burns similarly to petroleum diesel as it concerns regulated pollutants. On the other hand biodiesel probably has better efficiency than gasoline. Biodiesel fuel has better properties than petro-diesel fuel; it is renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics. Typical raw materials of biodiesel are rapeseed oil, soybean oil, sunflower oil and palm oil. Beef and sheep tallow and chicken fat from animal sources and cooking oil are also sources of raw materials. Commonly accepted biodiesel raw materials include the oils from soy, canola, corn, rapeseed, and palm. New plant oils that are under consideration include mustard seed, peanut, sunflower, and cotton seed. The most commonly considered animal fats include those derived from poultry, beef, and pork. Serious problems face the world food supply today. Food versus fuel is the dilemma regarding the risk of diverting farmland or crops for liquid biofuels production in detriment of the food supply on a global scale. Biofuel production has increased in recent years.

E. Biofixation of carbon dioxide by microalgae
Biofixation of CO2 by microalgae mass cultures represents an advanced, climate friendly biological process that enables the direct utilization of fossil CO2 streams produced from concentrated sources. Mitigation of GHG emissions would result from the conversion of the algal biomass to renewable biofuels [56,45,52 and 69]. Fossil-fuel-fired power plants contribute approximately one third of the total human-caused emissions of CO2. Fossil fuels will remain the mainstay of energy production well into the 21st century. However, increased concentrations of CO2 due to carbon emissions are expected unless energy systems reduce the carbon emissions to the atmosphere. To stabilize and ultimately reduce concentrations of the CO2 gas, it will be necessary to employ carbon sequestration – carbon capture, separation and storage or reuse. Carbon sequestration, along with reduced carbon content of fuels and improved efficiency of energy production and use, must play major roles if the nation is to enjoy the economic and energy security benefits, which fossil fuels brings to the energy mix. The availability of a carbon dioxide fixation technology would serve as insurance in case global warming causes severe restrictions on carbon dioxide emissions. Integrated processes in wastewater treatment and aquaculture were indicated as near-term applications of this technology. Microalgae applications in greenhouse gas mitigation could come through the development of wastewater treatment and aquaculture processes that combine their waste treatment features with reduction in greenhouse gas emissions and biofuels production. The greatest potential for microalgae biofixation processes is in developing countries, which should be included in any future development of this technology. The ultimate objective of microalgae biofixation of CO2 is to operate large-scale systems that are able to convert a significant fraction of the CO2 outputs from a power plant into biofuels. Biofixation of CO2 using photosynthetic organisms has been looked at as a way to stop or slow down the effects of global warming.
]]> <![CDATA[Micropropagation - Plant Tissue Culture - Role of Growth Regulators]]> https://www.biotechnologyforums.com/thread-2168.html Sun, 28 Apr 2013 08:52:12 +0000 NoahMachuki]]> https://www.biotechnologyforums.com/thread-2168.html
a.) 1992 - Habertlandt attempted to grow leaf palisade cells from different plants. However, these cells did not divide.
b.) 1934 - White established the need to supplement the medium with additives. He grew meristematic cells of tomato on a medium supplemented with yeast extracts, Vit B (thiamine, pyridoxine, and nicotinic acid), salts and sucrose.
c.) 1953 - Skoog and Miller discovered kinetin. This is a cytokine that plays a central role in organogenesis.
d.) 1959 - Orchids were discovered by Morel. These orchids were set free from viral diseases by Dahlias in 1960
e.) 1960's - Murashige and Skoog cloned plants invitro after discovering and publishing a recipe for Murashige and Skoog (M&S) medium.
f.) 1970's and 80’s marked the genesis of genetic engineering in tissue culture.

There are two main facts that scientists rely upon in plant tissue culture. Plants are totipotent and have ability to produce callus. Totipotency is the ability of a cell to develop into a whole plant or a plant organ when subjected to the right conditions. However, not all plant cells are totipotent. A callus is a mass of actively dividing undifferentiated cells produced by a plant tissue explant- an isolated portion of a plant that is used to initiate a culture (an inoculum)

Plants are sessile in nature and have long life span thus have developed plasticity. Plasticity is the ability to survive and adapt predation and extreme conditions than animals. They alter their metabolic processes and growth to suit the environment.

In plant tissue culture, ability of plants to initiate cell division from most of the tissues of a plant and the developmental responses to stimuli has been of a major interest. This plasticity allows one type organ of a plant to be produced from another hence regeneration of a whole plant when exposed to correct stimuli.

Plant tissue culture requirement
In order to initiate plant tissue culture, one needs; explants, suitable culture/growth media, aseptic conditions to curb growth of microorganisms, water, growth regulators (auxins and cytokinins), and frequent sub culturing to avoid accumulation of waste metabolite and enhance nutrition.

Culture medium
Plant tissue culture medium that is meant for cultivation of plant cells in vitro should contain mineral ions or essential elements in form of a mixture of complex salts, a source of carbon which is usually sucrose and organic supplements that supply vitamins and amino acids.

Organic supplements
Organic supplements supply vitamins and amino acids. The two main vitamins essential for in vitro tissue culture are myoinositol and thiamine while the most important amino acid is glycine.

Carbon source
Sucrose is the preferred carbon source essential in a culture medium. It is easily available, cheap, easily assimilated and stable.

Essential elements/nutrients
Essential elements are classified as macronutrients, micronutrients and an iron source. A combination of these elements is necessary for tissue culture.

Macronutrients are those elements that are supplied in large amounts for plant growth and development. They include; magnesium, sulphur, calcium, nitrogen, potassium, phosphorus and carbon which supplied separately. All these elements comprise more than 0.1% of plants’ dry weight. Nitrogen is mainly supplied as nitrate ions or ammonium ions. However, high concentrations of ammonium ions lead to acidification of the medium and increase vitrification.

Microelements are those elements that are needed in trace amounts in tissue culture media. However, they have diverse functions in plant growth and development. These elements include; iron, molybdenum, Manganese, iodine, cobalt, copper, boron and zinc.

Role of growth regulators in tissue culture

Due to the totipotency and plasticity of plant cells, certain manipulations to culture media are essential to determine certain developmental pathways of a plant cell. Plant hormones and their respective synthetic analogues are used as plant growth regulators. These growth regulators include;

Auxins- promote cell division and growth in explants. They support callus induction hence growth. However, high levels of auxins suppress organized growth promoting growth of meristem-like cells. The mostly used type of auxin for tissue culture is called 2, 4-Dichlorophenoxyacetic acid (2, 4-D).

Cytokinins- these are purine derivatives that support cell division. The two main types of cytokinins used in tissue culture are benzylaminopurine (BAP) and kinetine.

Gibberellins - these are naturally occurring compounds that are used in regulating plant cell elongation. GA3 is the most commonly used type of gibberellin in this technique.

Abscisic acid (ABA) - inhibits cell division in plants. It is mostly used in somatic embryogenesis to promote specific developmental pathways.

Auxins and cytokinins, as growth regulators, have basic roles to play in plant tissue culture. Often, they are used together but with different concentration rations which subsequently determine the type of culture regenerated. A high cytokinin to auxin ratio supports formation of shoots, whereas a high auxin to cytokinin ratio favors formation of roots. A balanced ratio favors production of callus.

Micropropagation procedure
1. Selection of an explant from a ‘mother plant’ that is healthy and vigorous. Usually, apical buds are preferred as explants but any other tissue can be used.
2. Establishment of this explant in a plant culture medium. A medium supports growth and cell division. Depending on the plant requirement, different types of media are used for specific types of plants.
3. Multiplication. In this stage, the explants give rise to a callus.
4. Differentiation and
5. Organogenesis

Culture types
Cultures are produced from ‘explants’. There are different types of cultures produced from explants depending on the conditions availed. They include;

Callus
This is an unorganized, growing and actively dividing mass of cells produced when both auxins and cytokinins are present in a culture medium, a procedure carried out in the dark to discourage differentiation. During formation of callus, there is morphological and metabolic dedifferentiation. Dedifferentiation results into inability of these cultures to photosynthesize hence attain a different metabolic profile from the ‘mother plant’. This feature precipitates addition of other culture components.

Manipulation of auxin to cytokinin ratios dictates root, shoot and somatic embryo development from which plants are produced. Callus cultures are classified as either compact or friable. Callus formation plays a central role in plant biotechnology.


Cell- suspension cultures
These cultures are produced from friable callus placed in a liquid medium and agitated. This releases single cells into the medium which under correct conditions, grow and divide to produce cell-suspension cultures. These cells are maintained as batch cultures in flasks.

Protoplasts
These are plant cells without cell walls. Removal of cell walls can be done either mechanically or by use of enzymes. The former method results in poor quality yields while the latter yields high and pure cells. The liquid medium used is not agitated to avoid damaging the protoplasts. However, the medium is put maintained under high osmotic pressure and shallow to allow aeration. Organogenesis or somatic embryogenesis can be used to produce whole plants on solid media. Many transformations are done through this method.

Embryo culture
Embryos are used to produce either a callus culture or a somatic embryo. An immature embryo from an embryogenic callus is the most recommended for regeneration of monocot plants.

Other culture types include; microspore culture, root cultures and shoot tip and meristem cultures. These cultures give rise to plant regeneration.]]>
a.) 1992 - Habertlandt attempted to grow leaf palisade cells from different plants. However, these cells did not divide.
b.) 1934 - White established the need to supplement the medium with additives. He grew meristematic cells of tomato on a medium supplemented with yeast extracts, Vit B (thiamine, pyridoxine, and nicotinic acid), salts and sucrose.
c.) 1953 - Skoog and Miller discovered kinetin. This is a cytokine that plays a central role in organogenesis.
d.) 1959 - Orchids were discovered by Morel. These orchids were set free from viral diseases by Dahlias in 1960
e.) 1960's - Murashige and Skoog cloned plants invitro after discovering and publishing a recipe for Murashige and Skoog (M&S) medium.
f.) 1970's and 80’s marked the genesis of genetic engineering in tissue culture.

There are two main facts that scientists rely upon in plant tissue culture. Plants are totipotent and have ability to produce callus. Totipotency is the ability of a cell to develop into a whole plant or a plant organ when subjected to the right conditions. However, not all plant cells are totipotent. A callus is a mass of actively dividing undifferentiated cells produced by a plant tissue explant- an isolated portion of a plant that is used to initiate a culture (an inoculum)

Plants are sessile in nature and have long life span thus have developed plasticity. Plasticity is the ability to survive and adapt predation and extreme conditions than animals. They alter their metabolic processes and growth to suit the environment.

In plant tissue culture, ability of plants to initiate cell division from most of the tissues of a plant and the developmental responses to stimuli has been of a major interest. This plasticity allows one type organ of a plant to be produced from another hence regeneration of a whole plant when exposed to correct stimuli.

Plant tissue culture requirement
In order to initiate plant tissue culture, one needs; explants, suitable culture/growth media, aseptic conditions to curb growth of microorganisms, water, growth regulators (auxins and cytokinins), and frequent sub culturing to avoid accumulation of waste metabolite and enhance nutrition.

Culture medium
Plant tissue culture medium that is meant for cultivation of plant cells in vitro should contain mineral ions or essential elements in form of a mixture of complex salts, a source of carbon which is usually sucrose and organic supplements that supply vitamins and amino acids.

Organic supplements
Organic supplements supply vitamins and amino acids. The two main vitamins essential for in vitro tissue culture are myoinositol and thiamine while the most important amino acid is glycine.

Carbon source
Sucrose is the preferred carbon source essential in a culture medium. It is easily available, cheap, easily assimilated and stable.

Essential elements/nutrients
Essential elements are classified as macronutrients, micronutrients and an iron source. A combination of these elements is necessary for tissue culture.

Macronutrients are those elements that are supplied in large amounts for plant growth and development. They include; magnesium, sulphur, calcium, nitrogen, potassium, phosphorus and carbon which supplied separately. All these elements comprise more than 0.1% of plants’ dry weight. Nitrogen is mainly supplied as nitrate ions or ammonium ions. However, high concentrations of ammonium ions lead to acidification of the medium and increase vitrification.

Microelements are those elements that are needed in trace amounts in tissue culture media. However, they have diverse functions in plant growth and development. These elements include; iron, molybdenum, Manganese, iodine, cobalt, copper, boron and zinc.

Role of growth regulators in tissue culture

Due to the totipotency and plasticity of plant cells, certain manipulations to culture media are essential to determine certain developmental pathways of a plant cell. Plant hormones and their respective synthetic analogues are used as plant growth regulators. These growth regulators include;

Auxins- promote cell division and growth in explants. They support callus induction hence growth. However, high levels of auxins suppress organized growth promoting growth of meristem-like cells. The mostly used type of auxin for tissue culture is called 2, 4-Dichlorophenoxyacetic acid (2, 4-D).

Cytokinins- these are purine derivatives that support cell division. The two main types of cytokinins used in tissue culture are benzylaminopurine (BAP) and kinetine.

Gibberellins - these are naturally occurring compounds that are used in regulating plant cell elongation. GA3 is the most commonly used type of gibberellin in this technique.

Abscisic acid (ABA) - inhibits cell division in plants. It is mostly used in somatic embryogenesis to promote specific developmental pathways.

Auxins and cytokinins, as growth regulators, have basic roles to play in plant tissue culture. Often, they are used together but with different concentration rations which subsequently determine the type of culture regenerated. A high cytokinin to auxin ratio supports formation of shoots, whereas a high auxin to cytokinin ratio favors formation of roots. A balanced ratio favors production of callus.

Micropropagation procedure
1. Selection of an explant from a ‘mother plant’ that is healthy and vigorous. Usually, apical buds are preferred as explants but any other tissue can be used.
2. Establishment of this explant in a plant culture medium. A medium supports growth and cell division. Depending on the plant requirement, different types of media are used for specific types of plants.
3. Multiplication. In this stage, the explants give rise to a callus.
4. Differentiation and
5. Organogenesis

Culture types
Cultures are produced from ‘explants’. There are different types of cultures produced from explants depending on the conditions availed. They include;

Callus
This is an unorganized, growing and actively dividing mass of cells produced when both auxins and cytokinins are present in a culture medium, a procedure carried out in the dark to discourage differentiation. During formation of callus, there is morphological and metabolic dedifferentiation. Dedifferentiation results into inability of these cultures to photosynthesize hence attain a different metabolic profile from the ‘mother plant’. This feature precipitates addition of other culture components.

Manipulation of auxin to cytokinin ratios dictates root, shoot and somatic embryo development from which plants are produced. Callus cultures are classified as either compact or friable. Callus formation plays a central role in plant biotechnology.


Cell- suspension cultures
These cultures are produced from friable callus placed in a liquid medium and agitated. This releases single cells into the medium which under correct conditions, grow and divide to produce cell-suspension cultures. These cells are maintained as batch cultures in flasks.

Protoplasts
These are plant cells without cell walls. Removal of cell walls can be done either mechanically or by use of enzymes. The former method results in poor quality yields while the latter yields high and pure cells. The liquid medium used is not agitated to avoid damaging the protoplasts. However, the medium is put maintained under high osmotic pressure and shallow to allow aeration. Organogenesis or somatic embryogenesis can be used to produce whole plants on solid media. Many transformations are done through this method.

Embryo culture
Embryos are used to produce either a callus culture or a somatic embryo. An immature embryo from an embryogenic callus is the most recommended for regeneration of monocot plants.

Other culture types include; microspore culture, root cultures and shoot tip and meristem cultures. These cultures give rise to plant regeneration.]]> <![CDATA[Bacteria Produce Diesel Fuel]]> https://www.biotechnologyforums.com/thread-2155.html Thu, 25 Apr 2013 15:50:35 +0000 bridgettpayseur]]> https://www.biotechnologyforums.com/thread-2155.html
Unfortunately, many of the biofuels currently being produced may cause problems for the environment. The production of these biofuels is not straightforward either, and requires many steps to get a final product that can be used. They require treatment with petroleum products, which means they may not be sustainable in the long run. In addition, growing corn crops to be used for biofuel production is causing increased costs for food, and increasing the land required for farming. The amount of land available to produce sufficient corn for both biofuel production and food is not adequate. Although many have suggested plant sources that grow more quickly that corn, require less space to grow, and will not affect the food supply, these sources have not been utilized extensively for biofuel production. Corn still remains the predominant choice for creating biofuels. Lastly, biofuels may not be structurally similar to conventional petroleum products, which would require upgrades to existing machinery in order for the fuel to be usable. For these reasons, other sources of biofuel are being investigated by energy scientists.

Recently, researchers at the University of Exeter, in collaboration with Shell, have engineered a strain of E. coli bacteria that can produce diesel fuel. This fuel is very similar in composition to traditional diesel fuel, and does not require treatment with petroleum products. Because it is so similar to traditional diesel fuel, systems that use diesel would not need to be upgraded in order to be able to use the fuel. This is a huge benefit over other biofuels, such as those produced from corn ethanol, because they do not need to be mixed with petroleum. The diesel biofuel produced by the E. coli could simply replace the conventional diesel fuel currently in use.

E. coli and other bacteria can transform organic molecules such as sugar into lipids which are inserted into the cell membrane. Lipids and diesel fuel have very similar structures. They are long chains of hydrogen and carbon, termed hydrocarbon molecules. The process of making lipids in E. coli has been modified by the researchers so that instead of producing normal lipids, the bacteria produce diesel fuel. So far, the researchers only have a small number of bacteria producing small quantities of the diesel. However, bacteria are often used in large scale production of many pharmaceuticals. Increasing the number of bacteria producing diesel and the yield would be a similar process. Once the researchers have determined that the diesel fuel being produced is adequate to be used in vehicles and industrial settings, scaling up production should be a straightforward process.

As more people become aware of the damages to the environment traditional energy sources cause, the development of cleaner, more sustainable energy becomes more important. As economies around the world begin to recover from the recessions of a few years ago, citizens will most likely be buying more products and traveling more, which will require more energy. Sustainable energy sources will become more important as demand increases, and supply decreases. In addition, laboratory produced diesel fuel and other clean, sustainable energy sources will enhance economic recovery, as fuel and energy prices will be less dynamic. The field of energy science is growing rapidly, to help keep the energy supply sufficient for human and technological growth.


References:

http://www.sciencedaily.com/releases/201...154911.htm]]>
Unfortunately, many of the biofuels currently being produced may cause problems for the environment. The production of these biofuels is not straightforward either, and requires many steps to get a final product that can be used. They require treatment with petroleum products, which means they may not be sustainable in the long run. In addition, growing corn crops to be used for biofuel production is causing increased costs for food, and increasing the land required for farming. The amount of land available to produce sufficient corn for both biofuel production and food is not adequate. Although many have suggested plant sources that grow more quickly that corn, require less space to grow, and will not affect the food supply, these sources have not been utilized extensively for biofuel production. Corn still remains the predominant choice for creating biofuels. Lastly, biofuels may not be structurally similar to conventional petroleum products, which would require upgrades to existing machinery in order for the fuel to be usable. For these reasons, other sources of biofuel are being investigated by energy scientists.

Recently, researchers at the University of Exeter, in collaboration with Shell, have engineered a strain of E. coli bacteria that can produce diesel fuel. This fuel is very similar in composition to traditional diesel fuel, and does not require treatment with petroleum products. Because it is so similar to traditional diesel fuel, systems that use diesel would not need to be upgraded in order to be able to use the fuel. This is a huge benefit over other biofuels, such as those produced from corn ethanol, because they do not need to be mixed with petroleum. The diesel biofuel produced by the E. coli could simply replace the conventional diesel fuel currently in use.

E. coli and other bacteria can transform organic molecules such as sugar into lipids which are inserted into the cell membrane. Lipids and diesel fuel have very similar structures. They are long chains of hydrogen and carbon, termed hydrocarbon molecules. The process of making lipids in E. coli has been modified by the researchers so that instead of producing normal lipids, the bacteria produce diesel fuel. So far, the researchers only have a small number of bacteria producing small quantities of the diesel. However, bacteria are often used in large scale production of many pharmaceuticals. Increasing the number of bacteria producing diesel and the yield would be a similar process. Once the researchers have determined that the diesel fuel being produced is adequate to be used in vehicles and industrial settings, scaling up production should be a straightforward process.

As more people become aware of the damages to the environment traditional energy sources cause, the development of cleaner, more sustainable energy becomes more important. As economies around the world begin to recover from the recessions of a few years ago, citizens will most likely be buying more products and traveling more, which will require more energy. Sustainable energy sources will become more important as demand increases, and supply decreases. In addition, laboratory produced diesel fuel and other clean, sustainable energy sources will enhance economic recovery, as fuel and energy prices will be less dynamic. The field of energy science is growing rapidly, to help keep the energy supply sufficient for human and technological growth.


References:

http://www.sciencedaily.com/releases/201...154911.htm]]> <![CDATA[The Use of Synthetic Biology to Help Conservation Efforts]]> https://www.biotechnologyforums.com/thread-2109.html Fri, 12 Apr 2013 17:30:41 +0000 bridgettpayseur]]> https://www.biotechnologyforums.com/thread-2109.html
With ecological research showing rapid destruction of ecosystems, and many species being endangered or killed off, conservation has become an important focal point for environmental scientists. The possibility of using synthetic biology has already been proposed to revive extinct species, with some going so far as to suggest the resurrection of species such as wooly mammoths. Bringing any animal or plant back from extinction, or the brink of extinction, has the potential to be problematic. There are concerns about how the species would survive in its new environment, and what type of effect it would have on the environment and other native species.

A long-extinct species like the mammoth would probably not be adapted to live in the current environment on earth. It would not be adapted for the climate, available food sources, predators, and even man-made factors such as pollution. Even if the species was able to survive and thrive once re-introduced into the wild, it might act as an invasive species. This means that the species could harm the environment, by depleting food supplies for other animals or preventing other native plant species from growing properly. Once an invasive species has become established in an ecosystem, it can be very difficult to remove. Endangered and more recently extinct species may not thrive either, even with assistance from synthetic biology. One large problem such species might face would be limited gene pools. This would prevent further adaptations to environmental changes. It could also result in defective recessive alleles becoming over-represented in the population, thereby propagating genetic diseases in these populations. In addition, cloning of many species has been problematic, resulting in individuals being born with severe defects, if they survive through the embryonic stage. More complex animals in particular have higher chances of experiencing these defects. If scientists were able to use synthetic biology to help breed endangered species, the individuals produced may not be viable.

A more likely scenario would be using synthetic biology to preserve species on the brink of extinction, including plants and animals. Synthetic biology could also be used to help improve the health and survivability of these endangered species. Species could be genetically engineered to express specific genes that allow them to survive and reproduce in their environment more efficiently. Synthetic biology is already successfully used in ecology, although in a more mundane manner. For example, a plant hormone called auxin is involved in helping plants develop strong roots. Scientists are able to easily produce the hormone in bacteria, and have used it to help maintain the growth of grasses in areas that are experiencing droughts.

Synthetic biology in general is a very contentious area of science, and raises a great deal of ethical concerns. These concerns are also seen in the altruistic extension of synthetic biology to conservation biology. One of the first concerns involves introducing genetically modified organisms (GMOs) into the environment. GMOs are a generally deemed worrisome by many ecologists, as the environmental and health impacts are not yet fully understood. Scientists worry that GMOs may cross-breed with native plants, thus spreading pesticide-resistance genes into weeds that could harm the environment. In addition, the long term use and consumption of GMOs by humans and other animals may have unknown consequences. As it stands, a great majority (up to 95%) of corn, soy, and cotton grown in the United States are GMO. Adding more species of plants and animals to the list of GMOs could cause additional unforeseen problems to the environment, as well as to human health.

References:
http://phys.org/news/2013-04-synthetic-b...dlife.html

http://www.scienceworldreport.com/articl...anisms.htm

http://www.todayonline.com/daily-focus/s...ic-biology]]>
With ecological research showing rapid destruction of ecosystems, and many species being endangered or killed off, conservation has become an important focal point for environmental scientists. The possibility of using synthetic biology has already been proposed to revive extinct species, with some going so far as to suggest the resurrection of species such as wooly mammoths. Bringing any animal or plant back from extinction, or the brink of extinction, has the potential to be problematic. There are concerns about how the species would survive in its new environment, and what type of effect it would have on the environment and other native species.

A long-extinct species like the mammoth would probably not be adapted to live in the current environment on earth. It would not be adapted for the climate, available food sources, predators, and even man-made factors such as pollution. Even if the species was able to survive and thrive once re-introduced into the wild, it might act as an invasive species. This means that the species could harm the environment, by depleting food supplies for other animals or preventing other native plant species from growing properly. Once an invasive species has become established in an ecosystem, it can be very difficult to remove. Endangered and more recently extinct species may not thrive either, even with assistance from synthetic biology. One large problem such species might face would be limited gene pools. This would prevent further adaptations to environmental changes. It could also result in defective recessive alleles becoming over-represented in the population, thereby propagating genetic diseases in these populations. In addition, cloning of many species has been problematic, resulting in individuals being born with severe defects, if they survive through the embryonic stage. More complex animals in particular have higher chances of experiencing these defects. If scientists were able to use synthetic biology to help breed endangered species, the individuals produced may not be viable.

A more likely scenario would be using synthetic biology to preserve species on the brink of extinction, including plants and animals. Synthetic biology could also be used to help improve the health and survivability of these endangered species. Species could be genetically engineered to express specific genes that allow them to survive and reproduce in their environment more efficiently. Synthetic biology is already successfully used in ecology, although in a more mundane manner. For example, a plant hormone called auxin is involved in helping plants develop strong roots. Scientists are able to easily produce the hormone in bacteria, and have used it to help maintain the growth of grasses in areas that are experiencing droughts.

Synthetic biology in general is a very contentious area of science, and raises a great deal of ethical concerns. These concerns are also seen in the altruistic extension of synthetic biology to conservation biology. One of the first concerns involves introducing genetically modified organisms (GMOs) into the environment. GMOs are a generally deemed worrisome by many ecologists, as the environmental and health impacts are not yet fully understood. Scientists worry that GMOs may cross-breed with native plants, thus spreading pesticide-resistance genes into weeds that could harm the environment. In addition, the long term use and consumption of GMOs by humans and other animals may have unknown consequences. As it stands, a great majority (up to 95%) of corn, soy, and cotton grown in the United States are GMO. Adding more species of plants and animals to the list of GMOs could cause additional unforeseen problems to the environment, as well as to human health.

References:
http://phys.org/news/2013-04-synthetic-b...dlife.html

http://www.scienceworldreport.com/articl...anisms.htm

http://www.todayonline.com/daily-focus/s...ic-biology]]> <![CDATA[An Introduction on Chemical Carcinogens]]> https://www.biotechnologyforums.com/thread-2018.html Thu, 07 Feb 2013 12:02:56 +0000 priyasaravanan_1406]]> https://www.biotechnologyforums.com/thread-2018.html We are exposed to ‘n’ number of chemicals everyday in both indoor and outdoor environment. The essential household products we use like toothpaste, soap, shampoos, detergents, drugs/medicines, floor and toilet cleaners, insect repellents, food additives, paints are all chemicals. In the same way we are exposed to chemicals in the outdoor environment while travelling or in work places with or without our knowledge. Any product meant for human use is evaluated for its safety before reaching the market. Toxicology, a branch of science takes the predominant position in evaluating the adverse effects of pharmacological drugs and chemicals on animals or humans, their metabolic pathway once entering the biological system and the biotransformation of such chemicals inside the body. This gives complete knowledge on the toxic effects, details on dosage and length of exposure causing undesirable effect, the metabolic pathway and its target site/organ of the studied chemical which makes the process of identifying the effect and treating the exposed individual easier.

Based on the adverse effect developed by a chemical it is classified either as a toxicant or carcinogen. The difference is that the damage caused by the former category is reversible whereas the damage caused by the chemicals under the latter category “carcinogens” is irreversible. Carcinogens are the substances with the potential to cause cancer in the exposed individual or animal and there are many chemicals identified with carcinogenic property. The history of chemical carcinogenesis states the first identified chemicals to be carcinogens were soot, coal tar, aromatic amine and azo dyes.

The intensity of the effect of a chemical carcinogen on the host is governed by various factors. Those include,
• Dose of the chemical
• Length of exposure
• Metabolic pathway (from the point of entry to the target organ)
• Biotransformation (Resultant product after the metabolism of the chemical in the body which may be more toxic than the original compound)
• Species, age and gender of the subject
• Altered carcinogenicity of the chemical on interaction with other environmental factors

Classification
Chemical carcinogens are classified into Genotoxic and non Genotoxic compounds based on their potential to cause damage to the DNA of the exposed animal or man. Those chemical carcinogens which alter the genetic material of the exposed individual can also be called as mutagens.

Yet another classification of chemical carcinogens is made based on the requirement of metabolic activation of the chemical to deliver the effect. Accordingly they are classified as primary chemical carcinogens, secondary chemical carcinogens and promoters.

Primary chemical carcinogens are the chemicals whose effect is seen immediately at the point of entry itself even without undergoing metabolism. Alkylimine, triethylenemelamine, mustard gas are some of the examples.

Secondary chemical carcinogens are also called as procarcinogens are the chemicals whose effects are observed in the exposed individual due to the resultant product of metabolism of the compound in the system. Thee metabolically activated forms of Benzanthracene, aflatoxinB1, safrole, carbon tetrachloride are some of the procarcinogens.

Next class is the promoters which are also called as cocarcinogens are the chemicals which are not only carcinogenic but also acts as inducers stimulating the carcinogenic property of other chemicals.

Exposure to Chemical carcinogens
Indoor Exposure: Formaldehyde, perchloroethylene, paradichlorobenzene, cigarette smoke, trisodium nitrilotriacetate, asbestos are some of the compounds present in indoor environment in the form of various products or accessories are carcinogenic in nature.

Outdoor Exposure: Regular exposure to compounds like Arsenic, benzene, beryllium, cadmium, hexavalent chromium (VI), nickel, ethylene oxide in work places causes cancer. Persons who are at risk of such exposures in industries should follow the prescribed guidelines of occupational health and safety measures in order to avoid risking their health.

Apart from the above discussed chemical carcinogens the other two types of carcinogens are physical and biological carcinogens. Ultra violet rays is the best example of physical carcinogen, exposure to which causes skin cancer and viruses with the potential to alter the genetic material of the host cell causing cancer are biological carcinogens. Human Papilloma virus, Hepatitis B and C virus are examples of cancer causing viruses.

Not all toxicants are carcinogenic. The ability to cause irreversible damage, the additive effect at each exposure, the mechanism of action on the basic genetic material, increased potential in the presence of other substances all makes a carcinogen differ from a toxicant.
]]> We are exposed to ‘n’ number of chemicals everyday in both indoor and outdoor environment. The essential household products we use like toothpaste, soap, shampoos, detergents, drugs/medicines, floor and toilet cleaners, insect repellents, food additives, paints are all chemicals. In the same way we are exposed to chemicals in the outdoor environment while travelling or in work places with or without our knowledge. Any product meant for human use is evaluated for its safety before reaching the market. Toxicology, a branch of science takes the predominant position in evaluating the adverse effects of pharmacological drugs and chemicals on animals or humans, their metabolic pathway once entering the biological system and the biotransformation of such chemicals inside the body. This gives complete knowledge on the toxic effects, details on dosage and length of exposure causing undesirable effect, the metabolic pathway and its target site/organ of the studied chemical which makes the process of identifying the effect and treating the exposed individual easier.

Based on the adverse effect developed by a chemical it is classified either as a toxicant or carcinogen. The difference is that the damage caused by the former category is reversible whereas the damage caused by the chemicals under the latter category “carcinogens” is irreversible. Carcinogens are the substances with the potential to cause cancer in the exposed individual or animal and there are many chemicals identified with carcinogenic property. The history of chemical carcinogenesis states the first identified chemicals to be carcinogens were soot, coal tar, aromatic amine and azo dyes.

The intensity of the effect of a chemical carcinogen on the host is governed by various factors. Those include,
• Dose of the chemical
• Length of exposure
• Metabolic pathway (from the point of entry to the target organ)
• Biotransformation (Resultant product after the metabolism of the chemical in the body which may be more toxic than the original compound)
• Species, age and gender of the subject
• Altered carcinogenicity of the chemical on interaction with other environmental factors

Classification
Chemical carcinogens are classified into Genotoxic and non Genotoxic compounds based on their potential to cause damage to the DNA of the exposed animal or man. Those chemical carcinogens which alter the genetic material of the exposed individual can also be called as mutagens.

Yet another classification of chemical carcinogens is made based on the requirement of metabolic activation of the chemical to deliver the effect. Accordingly they are classified as primary chemical carcinogens, secondary chemical carcinogens and promoters.

Primary chemical carcinogens are the chemicals whose effect is seen immediately at the point of entry itself even without undergoing metabolism. Alkylimine, triethylenemelamine, mustard gas are some of the examples.

Secondary chemical carcinogens are also called as procarcinogens are the chemicals whose effects are observed in the exposed individual due to the resultant product of metabolism of the compound in the system. Thee metabolically activated forms of Benzanthracene, aflatoxinB1, safrole, carbon tetrachloride are some of the procarcinogens.

Next class is the promoters which are also called as cocarcinogens are the chemicals which are not only carcinogenic but also acts as inducers stimulating the carcinogenic property of other chemicals.

Exposure to Chemical carcinogens
Indoor Exposure: Formaldehyde, perchloroethylene, paradichlorobenzene, cigarette smoke, trisodium nitrilotriacetate, asbestos are some of the compounds present in indoor environment in the form of various products or accessories are carcinogenic in nature.

Outdoor Exposure: Regular exposure to compounds like Arsenic, benzene, beryllium, cadmium, hexavalent chromium (VI), nickel, ethylene oxide in work places causes cancer. Persons who are at risk of such exposures in industries should follow the prescribed guidelines of occupational health and safety measures in order to avoid risking their health.

Apart from the above discussed chemical carcinogens the other two types of carcinogens are physical and biological carcinogens. Ultra violet rays is the best example of physical carcinogen, exposure to which causes skin cancer and viruses with the potential to alter the genetic material of the host cell causing cancer are biological carcinogens. Human Papilloma virus, Hepatitis B and C virus are examples of cancer causing viruses.

Not all toxicants are carcinogenic. The ability to cause irreversible damage, the additive effect at each exposure, the mechanism of action on the basic genetic material, increased potential in the presence of other substances all makes a carcinogen differ from a toxicant.
]]> <![CDATA[Ancient DNA could tell a lot of different stories]]> https://www.biotechnologyforums.com/thread-1899.html Sat, 01 Dec 2012 11:12:13 +0000 BojanaL]]> https://www.biotechnologyforums.com/thread-1899.html
Ancient DNA represents DNA material extracted from old biological samples. Unlike classical DNA analysis, these specimens are of less quality. Archeological discoveries of different animal and plant materials precede DNA analysis. Even though DNA is present in each cell of the living organism, decomposition of the body after death limits the sources that could provide sufficient DNA for the further analysis. In the rare situations when body is entrapped in the ice or amber, high quality and quantity DNA is available. Various insects, plants and bacterial species were successfully investigated after DNA was extracted from amber entrapped specimens. For animal species, usual source of DNA are bones and teeth. Weather conditions (especially temperature and moisture) greatly affect the speed of DNA decay. At temperature of -5 Celsius, mitochondrial DNA is degraded to 1 base pair after 6.830.000 years. Degradation of the nuclear DNA is two times faster than mitochondrial. Using PCR method, scientists were able to multiply and investigate some very old samples dating back from Cretaceous period (145-66 million years ago). Not all ancient DNA samples are million years old. Some ancient DNA analysis investigates remains of much younger origin.

One recently published article investigates climate changes based on analysis of the ancient urine. Rock hyrax is cute little creature that looks like a rodent but is actually more closely related to the elephant. They inhabit rocky environment in Sub-Saharan Africa and Middle East. These social animals have specially designated area serving as mutual (communal) toilets. They are used for years, containing urine samples of a lot of hyrax generations. Urine crystallizes in time, forming stratified accumulations known as middens. Scientists found well preserved 10 thousands year old African middens that could provide more insight in climate changes associated with the hyrax habitat. Collected samples were investigated for organic molecules, metabolites and plant derived molecules. Forensic DNA analysis provided more information on the type of diet they have in the past revealing what plants were available 30.000 years ago. Since plant species are typical representatives of the each climate zone, list of available species on the hyrax menu precisely inform scientist which climate type existed 30.000 years ago. Middens were used for pollen analysis as well. That analysis increased the accuracy of predicted climate type. Given results showed that southern African climate underwent series of complex climate changes after last ice age (~20 000 years ago). Future experiments will investigate changes middens undergo when exposed to computerized simulations of past climate changes. Scientists are hoping that provided information would be helpful in revealing mysteries behind fast and unpredicted weather changes in this dynamic environment.

Another location and another set of animal excrements also provided evidence on previously lived flora and fauna. North West area of Australian continent is arid and any kind of old DNA is hard to find. However, scientists managed to found 700 - 30.000 years old samples of urine, fecal matter, hair, bones and eggshells cemented together in three locations. Different species (now extinct common brushtail possum and various arid grasses) that inhabited Western Australia were easily detected thanks to genetic analysis. Previous investigations focused on carbon dating, macrofossils and pollen identification; DNA analysis expanded previous data and helped in creating final image of the environment from the past.

Analyses of this kind are especially important for endangered species. Future conservation plans and efforts will work better if scientists become fully familiar with extinct species and be able to compare existing environmental data with the ones from the past.]]>
Ancient DNA represents DNA material extracted from old biological samples. Unlike classical DNA analysis, these specimens are of less quality. Archeological discoveries of different animal and plant materials precede DNA analysis. Even though DNA is present in each cell of the living organism, decomposition of the body after death limits the sources that could provide sufficient DNA for the further analysis. In the rare situations when body is entrapped in the ice or amber, high quality and quantity DNA is available. Various insects, plants and bacterial species were successfully investigated after DNA was extracted from amber entrapped specimens. For animal species, usual source of DNA are bones and teeth. Weather conditions (especially temperature and moisture) greatly affect the speed of DNA decay. At temperature of -5 Celsius, mitochondrial DNA is degraded to 1 base pair after 6.830.000 years. Degradation of the nuclear DNA is two times faster than mitochondrial. Using PCR method, scientists were able to multiply and investigate some very old samples dating back from Cretaceous period (145-66 million years ago). Not all ancient DNA samples are million years old. Some ancient DNA analysis investigates remains of much younger origin.

One recently published article investigates climate changes based on analysis of the ancient urine. Rock hyrax is cute little creature that looks like a rodent but is actually more closely related to the elephant. They inhabit rocky environment in Sub-Saharan Africa and Middle East. These social animals have specially designated area serving as mutual (communal) toilets. They are used for years, containing urine samples of a lot of hyrax generations. Urine crystallizes in time, forming stratified accumulations known as middens. Scientists found well preserved 10 thousands year old African middens that could provide more insight in climate changes associated with the hyrax habitat. Collected samples were investigated for organic molecules, metabolites and plant derived molecules. Forensic DNA analysis provided more information on the type of diet they have in the past revealing what plants were available 30.000 years ago. Since plant species are typical representatives of the each climate zone, list of available species on the hyrax menu precisely inform scientist which climate type existed 30.000 years ago. Middens were used for pollen analysis as well. That analysis increased the accuracy of predicted climate type. Given results showed that southern African climate underwent series of complex climate changes after last ice age (~20 000 years ago). Future experiments will investigate changes middens undergo when exposed to computerized simulations of past climate changes. Scientists are hoping that provided information would be helpful in revealing mysteries behind fast and unpredicted weather changes in this dynamic environment.

Another location and another set of animal excrements also provided evidence on previously lived flora and fauna. North West area of Australian continent is arid and any kind of old DNA is hard to find. However, scientists managed to found 700 - 30.000 years old samples of urine, fecal matter, hair, bones and eggshells cemented together in three locations. Different species (now extinct common brushtail possum and various arid grasses) that inhabited Western Australia were easily detected thanks to genetic analysis. Previous investigations focused on carbon dating, macrofossils and pollen identification; DNA analysis expanded previous data and helped in creating final image of the environment from the past.

Analyses of this kind are especially important for endangered species. Future conservation plans and efforts will work better if scientists become fully familiar with extinct species and be able to compare existing environmental data with the ones from the past.]]>