[sale0303]

Creation of chain DNA in laboratories leads to the creation of artificial organisms. Scientists are now able to make a DNA chains "on demand", such as they need. There are numerous reviews on this revolutionary scientific discovery, because many have fear of the outcome. Like the experts say: "you should not be playing God."

After 15 year-work, a team of U.S. researchers has developed the first auto reproductive living cell, which is controlled by a synthetic genome. Critics warn of the risk of developing artificial organisms. "It is a cell that is derived from fully synthetic chromosome, made of four bottles of chemicals that make up DNA parts," said Craig Venter, chief researcher at the Institute Jay Craig. Venter told reporters that the experiment began with a live cell, which is then processed using a synthesized genome, after which the cells pass through a "million steps of replication." The researchers first constructed a kind of "genetic software" bacteria, which were then transplanted into the cell, and eventually frozen. Otherwise, Venter said that two years ago, managed to make sensitization of bacterial genome, but had not been able to transplant it into a cell.

Except synthesizing the genome (the complete hereditary basis of an organism) by fusing the chromosomes which contain the DNA of the organism, the genome researchers added "watermarks" to distinguish them from natural. These tags, in fact, contain the names of all 46 authors and researchers who worked on the project, as well as the official website, so that anyone who succeed to perform decoding can send e-mail to the team. In addition, three quotes of Irish writer James Joyce are included. One of them sounds as follows: "To live, to be mistaken, to win, to create life out of life." With good reason, apparently. Venter added that "this is the first time that a synthetic DNA is in full control of a single cell." That is why he will continue to work on the construction of the bacteria to be able to perform useful functions.

Algae from glass bottles AGAINST "greenhouse"

This method could be used in the manufacture of medicines, vaccines and biofuel, the new, so-called "clean energy" for the refinery. It also, could enable the production of algae for absorption and clearance of carbon dioxide, the most dangerous environmental pollutant, according to the report published in the journal "Science." "We are on course to develop a very powerful apparatus in an attempt to control biological processes," said Craig Venter, researcher who was involved in mapping the human genome in the last 10 years. During that research, he determined the location of each human gene and its specific structure and function.

Opening Pandora's Box

Critics warn that Venter and his colleagues that way entered in the danger zone, because "they have created artificial organisms that have not been fully studied and understood." Venter stood in front of the public, and, in his defense, he said that he "wasn’t trying to play God." "It's a classic charge that critics point when scientists discover something new in medicine or biology. Man has always lived in attempt to control nature. Didn’t that cause creating the domestic animals," said the researcher. He believes that this is not an act of opening a Pandora's box, but on the contrary - "This is a step, a small step forward in realizing and understanding the nature and functioning of life, and perhaps, in discovering ways to control microbial world, to improve people's lives."

This experiment raised many ethical questions. Pat Mooney, director of ETC Group in Canada, said that the creation of artificial cells "is not SOS shop for all our troubles in the society. It is more likely that this will create a series of new problems." Among them, according to the possibility of abuse, primarily belong weapons for bioterrorism. Rejecting the possibility, Winter concluded that "technology and the cells are not for sale”.

Strive to use technology in order to improve the quality of human life, as well as to improve knowledge and understanding of cellular life is spreading with great speed. Although there are different opinions whether this kind of technology should be applied, the progress of science seems unstoppable. We can only imagine the incredible advantages that future generations are going to experience thanks to biotechnology achievements.

[BojanaL]

XNA and semi-synthetic DNA

Life on Earth developed thanks to ability of DNA and RNA to replicate and transfer information about all living processes in the cell to the next generation. This unique and highly efficient natural strategy is billions years old but scientists still struggle to mimic this event in laboratory conditions. Although it sounds like a science fiction, technological improvements in the past decade allowed different scientific teams to successfully create synthetic nucleotides, XNA as well as synthetic and poly-synthetic organisms, which opened a whole new window of opportunities in the field of nanotechnology, medicine and biotechnology.

DNA molecule has specific double helix structure that consists of four complementary connected nucleotides. These four nucleotides create numerous genetic combinations. Their expression result in proteins responsible for all metabolic processes in living creatures. Different species have different sized genomes, but DNA in all species in the world is organized in the same way. No matter if you are yeast or a bird - you will still have DNA made of four nucleotides. Although they form enough genetic combinations, scientists wanted to explore why nature favored these four nucleotides to build entire life on the Earth and to examine ability of artificial nucleic acids to act like DNA and RNA.

More than a decade, scientists are experimenting with synthetic nucleotides. XNA is synthetic DNA molecule created out of artificial nucleotides. It is able to carry the same information as DNA and to replicate when needed. Basic difference between natural and XNA nucleotides lays in sugar component: pentose is replaced with synthetic analogs. New nucleotides named: ANA, FANA, TNA, LNA, CeNA, HNA contain between 4 and 7 carbon atoms (natural nucleotides have 5) and FANA even contains fluorine. Chemical alterations allow artificial nucleotides to resemble classic DNA molecule both structurally and functionally. Polymerase is an enzyme essential for DNA replication. Compartmentalized self-tagging technique is applied to build a polymerase that could recognize and successfully synthesize XNA from a DNA template. Another enzyme that works as “reverse transcriptase” is able to convert XNA back to DNA. With high accuracy in replication (over 95%), this system allows scientists to replicate and propagate genetic information efficiently. XNAs proved to be able to store and copy data just like natural DNA, but their ability to change and adapt to the environmental conditions was questionable. To test this issue, XNAs were subjected to the natural selection artificially, through different mutations. HNA successfully coped with selective pressure and evolved in different forms, proving that artificial XNA is able to evolve just like DNA and RNA during classical Darwinian evolution. Unlike DNA, XNA is resistant to natural enzymes. This characteristic is very important because application of DNA and RNA in biotechnology and medicine is restricted due to high biodegradability in living organisms. Since XNAs couldn’t be degraded, they could easily replace DNA and RNA in the field of diagnostics and therapeutics.

Another experiment using synthetic nucleotides focused on specific letters that form genetic code. Idea of expanding genetic code with additional nucleotides is not new, but lot of potential molecules failed in the past due to inability to connect with other nucleotides or to replicate. One synthetic pair, however, blends with four other nucleotides and replicate in the tube easily. These nucleotides are better known as NaM and 5SICS. They are complementary, but unlike other four nucleotides, they don’t form hydrogen bonds. Strong hydrophobic forces hold these nucleotides in DNA molecule. They change DNA shape from double helix to overlapped and intercalated DNA structure. Main concern with this altered DNA helix was ability of enzyme polymerase to approach DNA and complete replication successfully. Double helix structure is essential for the enzyme and despite low expectations, newly incorporated nucleotides showed ability to align perfectly (edge to edge) when gripped by the enzyme. One explanation of this unusual phenomenon is associated with chemical bonds; it is quite possible that NaM and 5SICS would not be able to form desirable structure during replication if they are connected through rigid covalent bonds. Discovery of new bases that could easily blend with natural nucleotides opened some new possibilities. Additional nucleotides could “spell” more words in genetic language, and if they become able to self-replicate efficiently - first semi-synthetic organism could develop soon. Scientists believe that expanded genetic code will be highly appreciated in precise molecular probing and in nanotechnology.