Discoveries of the Year: from stem cells to genome decoding

Alchemy is the science of the YearArtem Tuntsov, "Newspaper.
Ru»The scientific achievements of the year, according to the journal Science, turned out to be cellular alchemy – the transformation of cells from one type to another in several ways, direct observations of planets from other stars and new genome sequencing technologies.

In addition to the top 10 of the outgoing year, the magazine also offers a short list of branches of science from which you can expect a breakthrough in the new year.

Unlike the final lists published by popular publications (probably the most famous of them is the Time magazine list), the scientific journal Science traditionally publishes the 10 most notable achievements of the year. We are almost always talking about published works and almost always about some specific results, not new experimental or theoretical methods.

Therefore, in the rating published in today's issue, there is no mention, for example, of the launch of the Large Hadron Collider (LHC) or the work of the Phoenix probe in the Martian Arctic – two, without a doubt, notable events of the outgoing year. Their time has not come yet: for Phoenix – because scientists have not yet processed the data transmitted to them and have not published the results of their analysis, for LHC – for other reasons. There are no stories about quantitative mass spectrometry or new spectroscopy techniques here, simply because scientists have not yet managed to do anything truly breakthrough with the help of these methods.

The scientific breakthrough of the year, according to Science, was the reprogramming of adult cells.Just two years ago, Japanese Shinya Yamanaka and his collaborators managed to turn cells from the tail of a laboratory mouse into pluripotent cells – a complete analogue of embryonic stem cells, which can make any cell of the body (but not the placenta).

At the end of 2007, the same Yamanaka and a couple of other scientific groups from the USA achieved the same result with human cells (skin cells, however, were taken not from the tail, which Yamanaka does not have, but somewhere in the elbow area).

Stem cell induction, as the authors called the method, resolved the growing ethical conflict between the prospects for treating various diseases with stem cell transplantation and the need to extract them from embryos. The discovery was warmly received even by moderate religious figures and in last year's Science list was second only to unexpectedly large variations of the genome from person to person, revealed after reading the DNA sequence of James Watson, 50 years earlier revealed the structure of the double helix.

This time the reprogramming of the cells got to the top. Several works on this topic were published at once during the year. From 4 to 3, and in some cases to 2, the number of genes that have to be injected into the cell with the help of a virus in order to return it to an undifferentiated, embryonic state has decreased. In addition, viruses embedded in the host genome have been replaced by an adenovirus, which only produces the necessary proteins, leaving the cellular DNA intact. And some genes were completely replaced with simple chemical additives.

In addition, this year biologists have learned how to grow pluripotent stem cells from the skin of adults with severe hereditary diseases, and from them to obtain tissue cells of diseased organs. This immensely facilitates laboratory work on the study of rare diseases and promises quick and simple tests for individual drug intolerance.

But the most striking, of course, was the August article by Douglas Melton and his colleagues in Nature, who succeeded in real cellular alchemy. They were able to directly, bypassing the stem stage, turn a cell of one type into another, while in a living organism. After some manipulations, part of the mouse pancreatic cells producing digestive juices turned into beta cells secreting insulin.

Imagine, you wake up in the morning, and somewhere at the bottom of your back, where there was only skin before, a second head suddenly grew. Unbelievably. But in terms of differentiation, the gap between exocrine cells and beta cells is as big as between skin cells and neurons. However, about the head – it's still too far an analogy. No one has yet managed to grow a part of the body from a stem cell, although scientists have made one whole organ – the prostate of a mouse – in this way.

Right behind the reprogramming of cells, as in last year's Science list, astronomy.

This time, the second place is not the origin of ultrahigh–energy cosmic rays, but the first direct images of extrasolar planets – three satellites of the star HR8799 in the constellation Pegasus and one satellite Fomalhaut - the brightest star of the constellation Southern Fish. Two teams of scientists from Canada and the USA managed not only to see the planets, but also to notice their movement relative to the central stars.

Direct observations of planets are very important: only by analyzing their light, it will be possible to find out something besides mass and size - for example, to identify the presence and chemical composition of the atmosphere, or even to notice traces of chlorophyll molecules in the spectrum. So far, however, there is not much sense from these observations: the satellites of Fomalhaut and HR8799 are very hot and young planets, which so far even glow not with the reflected light of the star, but with their own incandescent surface.

The top three leaders in the study of the genetics of tumor cells.Although this year I did not think to dry up the flow of work establishing the connection of some congenital mutation with an increased likelihood of developing a particular disease, including cancer, in this case we are not talking about them.

The development of genome sequencing methods, which are still to be discussed, has made it possible to isolate a large number of DNA sections of cancer cells themselves that distinguish them from healthy cells of a particular organism. Among them are numerous mutations in the cells of glioblastoma (a dangerous brain tumor) and pancreatic cancer. The first complete genome of a tumor cell was also obtained.

However, these works also brought some disappointment. Unfortunately, the mutations that distinguish cancer cells turned out to be extremely diverse. No universal "cancer genes" were found, by correcting mutations of which it would be possible to return the cancer cell to the path of healthy development. Of course, numerous Pten, p53 and other genes and signaling networks, modifications of which are characteristic of cancer, remain an important area of research. But even cases that are very similar in symptoms at the genetic level differ very much from patient to patient. Some researchers even dare to say that cancer – be it lung cancer, brain tumors or prostate cancer – is not just one disease, but thousands and millions of diseases, individual for each patient.

The fourth place was given by the editors of Science to a new type of materials with the property of "high-temperature" superconductivity. Previously, all these superconductors were based on copper compounds, a classic example is the "ceramic washers" made of copper, barium and oxygen available in any well–equipped physics room, preserving superconductivity at the temperature of liquid nitrogen. However, at the beginning of the year, Japanese physicists reported on a whole family of new superconductors based on iron in combination with lanthanum, arsenic, fluorine and the same oxygen. By spring, manipulating the relative content of impurities, the Chinese brought the critical temperature to 56 ^o K (-217 ^O on the Celsius scale). Of course, the temperature of liquid nitrogen is still far away, but after all, new superconductors have been studied for less than a year, not more than 20 years. In addition, there are indications that superconductivity in "iron" superconductors is not arranged in the same way as in "copper".

In fifth place were biochemists and structural microbiologists who study the behavior of various proteins and the mechanisms of their binding to various molecules. New computing power has helped to calculate how proteins change their shape during chemical reactions, and experimental methods that have appeared in recent years have allowed us to see this interaction in dynamics and even find out that in some cases the results of theoretical calculations coincide with reality. The most remarkable example is the behavior of the ubiquitin molecule – a kind of intracellular "black mark" that manages to bind to a wide variety of damaged or simply done their job proteins, thereby signaling to cellular structures that it is time to scrap the protein.

The sixth position belongs to various catalysts that allow to extract energy in an environmentally friendly and at the same time relatively cheap way. For example, the phosphoric-cobalt compound, which can replace expensive platinum in the reactions of splitting water into hydrogen and oxygen under the influence of sunlight. A similar "photosynthetic" reaction was also realized with the help of a complex compound based on manganese. At first glance, the method of producing combustible hydrocarbons from carbon dioxide, water and sunlight does not seem very environmentally friendly, but this method only simulates photosynthesis, which occurs in all green plants. What could be more environmentally friendly?

The seventh place was taken by German researchers who, using a new microscopic method, made a whole documentary about the first stages of embryo development, tracing each cell of a tiny body – their movement, division and differentiation. Even if we put aside the scientific component, it is impossible not to note the aesthetic appeal of the video showing how an embryo that already looks like something real develops from one cell.

The eighth place is in fat. More precisely, "good", brown fat, which does not store energy, making us fatter and uglier, but, on the contrary, consumes it, burning calories and warming in the cold. As it turned out, brown fat cells are much closer in origin to muscle cells than to their "white brothers". In addition, it is possible to chemically influence the development of these cells, forcing the body to synthesize more "good" fat. It is also possible to reduce the number of white fat cells – at least now scientists know where the adipocyte progenitor cells are located and how to distinguish them.

On the ninth line is a group of German physicists and computer scientists who managed to calculate the masses of the proton and neutron "from the first principles" of quantum chromodynamics. The calculation confirmed that most of the mass of everything we see in the universe is just the energy of quantum vacuum oscillations.

Finally, the tenth place belongs to new methods of genome sequencing. The successes of the California companies Illumina and Applied Biosystems made it possible to read the complete sequence of human DNA piece by piece – all 3 billion pairs of letters-nucleotides – and stitch them into a single coherent sequence, now it can be done not in a few years, but in just two weeks. And it will cost not many millions of dollars, but only about $ 100 thousand. Thanks to this, scientists now have the genomes of not only several whites and one "synthetic" person, but also the genomes of a Negro and a Han Chinese. New sequencing technologies were also used to decipher the mammoth genome, which is now known to us by about 70%. And some companies are already promising to present technologies next year that will allow reading the complete human genome for just $ 5 thousand.

The editors of Science expect the main successes of the next year from the same genetics, astrophysics and particle physics.

First of all, the publication of complete genomes of a whole set of important agricultural crops is planned for next year. This information will show scientists in which direction it is necessary to work in order, for example, to make corn more resistant to droughts, and soybeans richer in organic compounds suitable for creating biofuels. Next year will also mark the 200th anniversary of Darwin's birth and the origin of species at the genetic level should finally become clear, Science believes. Works identifying genes that make it impossible to crossbreed have already begun to appear this year, and next year they may form a completely complete picture of speciation at the genetic level.

In addition, a year later, in December 2009, the "second Kyoto" is to be held in Copenhagen. At a meeting of world government leaders, they will have to decide how to deal with global warming, its causes and consequences after the expiration of the Kyoto Protocol in 2012. It is also necessary to deal with the consequences of the rapidly accelerating oxidation of the oceans due to an increase in the level of CO2 in the atmosphere. What to do with acidic waters – no one knows yet.

On the practical side, Science predicts, next year we should expect a serious revival of conversations about using the successes of neurophysiology in criminology. Although an ultra-reliable "lie detector" of a new generation is unlikely to be created, do not be surprised if the science of the physiological structure of the brain debuts in the courtroom.

Finally, the launch of the Large Hadron Collider (LHC) near Geneva, postponed due to the September accident, is scheduled for next year, and data on ultra-high-energy particle collisions is already being processed at Tevatron in the US state of Illinois. This data already shows something very, very unusual. And something equally unusual has already been recorded by astrophysicists in the energy spectra of cosmic rays obtained in the PAMELA and ATIC experiments. It is possible that there is a direct connection between these intriguing results and next year will be the year of the birth of a new, "dark" physics.

We'll start checking in two weeks.

Portal "Eternal youth" www.vechnayamolodost.ru19.12.2008