Who to blame for the new viruses

The bacteria Pseudomonas fluorescens under a microscope. It is the combination with the virus and the scientists used a driving force of evolution is primarily the interaction between species, rather than pressure from the environment.

At least in the case of the formation of new strains of viruses all the case. This finding may be useful not only biologists, but also doctors.
The experiment, described in the journal Nature, biologists conducted from the UK. The researchers took a culture of bacteria Pseudomonas fluorescens and F2 bacteriophage virus that infects bacterial cells. Naturally, part of the bacteria eventually fashioned defense against the virus, and viruses, in turn, raised new and mutated strains. A surprise for the scientists was that the rate of evolution of the virus was significantly higher than where he had constantly faced with changes in the protective systems of bacteria.



Good viruses
Viruses that infect bacteria exclusively, in the experiments even try to use the medicine to fight off invading pathogens. However, the widespread introduction of antiretroviral therapy too early to speak: viruses so far used only for the formation of immunity as a vaccine or for gene therapy.

Prior to that, says Steve Patterson, one of the authors, biologists assumed that most often the main driving force of evolution is adaptation to the environment and that the rate of evolution of viruses does not depend on how successfully resist the infection of cells. But where the ability of bacteria to develop new protective mechanisms has been artificially suppressed, viruses evolved more slowly, and get to the end of the experiment the number of different strains to be substantially less. In other words, the emergence of new viruses found "guilty" of their victims!



Evolution. Reproduced in vitro.
Earlier, at the dawn of evolutionary theory, biologists could see only the results of the process, which took place over hundreds of thousands or even millions of years. Charles Darwin, for example, to create his theory prompted a variety of bird species in the Galapagos Islands, which he visited them during the voyage of exploration on the research ship "Beagle". Monitoring living organisms allowed to come to the conclusion that new species arise as a result of natural selection. However, the temporal and spatial evolution mashstaby, seem to exclude any possibility of experimental reconstruction of the evolution in the laboratory.



Myth Darwin
The popular and totally false myth of the theory of evolution: Darwin's alleged is that "man descended from apes." In fact, Darwin's theory states that the new species (though man, even though the virus of swine influenza H1N1/09) arise as a result of natural selection. A chimpanzee, incidentally, does not the ancestor of man, rather, a parallel branch.

Even the appearance of "superkrys" in Britain, where zoologists discovered rodents that are resistant to the widespread poison, too, still there was no experiment. To investigate the evolution in strictly controlled conditions, no rats, nor any more animals were not good. The first large-scale experiment was initiated in 1980 in bacteria.

This experience, in which scholars in the twenty years have traced over 40 thousands of "generations" of E. coli, gave enough material for several scientific papers and you'll know that the formation of new traits in an organism still occurs. Starting from a certain generation of bacteria begin to digest before "inedible" for their substance, and the severity of the experimental conditions enabled follow the mutations that led to the emergence of new capacity - about this experiment GZT.RU wrote in 2009.

Bacteria divide rapidly, relatively easy to be found in large quantities (grams conventional "live" yogurt, for example, contains ten million bacteria), they can freeze and unfreeze - the less than ideal site for research? Partly to the fact that the bacteria in a nutrient medium is a very rough likeness of a real ecosystem, which are almost always more than one species.



Why is evolution?
In preparing this material for scientific observer GZT.RU question arose: how to speak correctly on the joint evolution in the case of bacteria and viruses that are outside the bacteria are inactive? Is the bacterium only environment for the virus?

This question is answered, Alexander Markov, Doctor of Biological Sciences and an expert on the theory of evolution: cell and the virus has not merged into a single organism and do not reproduce as a whole. Their "goal" are different - so the evolution of the virus and the evolution of bacteria are two of the process, not one and the same process. And since these two processes affect each other, we can speak of co-evolution.



Power competition
If the bacteria live in the nutrient solution, their natural selection could only be due to the efficiency of assimilation "grazing". Who is most fully transforms the available resources and faster all the shares - that eventually dominates, it is seen researchers, who placed long-term experience with E. coli.

But in the real world that does not happen: in addition to a breeding ground for the organism is and opponents. Hare, which can cost one piece of bark in the night, but who runs at a speed of two kilometers per hour - simply be eaten. As well as running, but who needs three times the quantity of food is unlikely to survive in the hungry period. Competition imposes additional restrictions, supports the balance between different areas of development ... but how big its contribution?

Placed experiment allowed to answer. Scientists have viruses and bacteria, "graze" them together and then divided them into two groups: one bacterium each day were replaced by fresh, while the other remained "descendants" of those who were originally. Where the bacteria have not changed, there was constant fighting virus with the protective systems of bacterial cells, but where the cells each time updated - there is essentially no evolution in bacteria may not occur, viruses, all 24 of the day attacked the same cell.

And, as mentioned above, the constant proximity to the changing bacteria and help accelerate the evolutionary process in itself viruses. And, what is particularly interesting, biologists could not even calculate the exact number of mutations: 23 in the "joint" and 11 "single" group. More than double the difference!

But that's not all. Genetic analysis of viruses also showed that a "joint" group was formed six different strains, which, in fact, could become the basis for new types of virus. Which of this conclusion is physicians who study, for example, the adaptation of influenza virus to the variability of human immunity - is not yet clear, but perhaps the result of British biologists will interest not only specialists in evolutionary theory.