09 January 2017

What biologists did in 2016 – part two

Kirill Stasevich, "Science and Life"

In the first part of our annual review, we kept thinking about mutations – mutations this, mutations that, mutations that cause cancer, mutations that cause obesity. Mutations are a variety of anomalies in the DNA sequence, and they can be both harmful and useful, or simply none, that is, unnoticeable.

But, of course, we are most interested in harmful mutations, and every year researchers describe many genetic defects that can provoke certain diseases; for example, researchers from Moscow State University managed to find another mutation that increases the likelihood of a heart attack, and the staff of the St. Petersburg Children's Hospital. The Judas in Memphis described in their article in Nature Medicine how schizophrenic voices in the head can arise due to a genetic anomaly.

However, sometimes harmful mutations put biologists at a dead end – because in fact no harm comes from them. In the spring, an article was published in Science, the authors of which, using the example of the most ordinary people, showed how genes that are considered vital sometimes turn out to be unimportant – their absence does not affect human health in any way. Another article on the same topic was published a month later in Nature Biotechnology – it talks about mutations that should cause severe genetic diseases, but sometimes for some reason they do not. The reasons for which harmful mutations are neutralized can be very different: for example, a mutant gene may have an additional healthy copy, or the situation is saved by the interaction of genes, or epigenetic mechanisms interfere with the situation. (We will not tell you in detail about epigenetics now, just recall that, for example, obesity can pass from generation to generation without any special mutations, only thanks to epigenetic molecular mechanisms.)

Many mutations and many diseases come to us with age – the cells of the body stop coping with DNA damage, accumulate harmful garbage in themselves, being unable to process it, so in the end they either have to turn into a malignant monster or die. Obviously, if we could somehow slow down aging, not to mention reverse it, it would be, without exaggeration, the beginning of a new era on Earth.

Aging has long been no secret, and although it depends on a lot of factors, researchers already more or less understand what's what, and are trying to find methods to combat aging in general and age-related diseases in particular. However, it is not without loud punctures: so, in 2016, apparently, the story of young blood, which is still not able to rejuvenate old tissues and organs, finally ended.

But, on the other hand, in the outgoing year, as many as three works were published, in which it is about the abolition of aging and which, without exaggeration, can be attributed to the most high-profile biomedical achievements. The first of them, published in Nature, says that mice can prolong their life by as much as 20% if their body is cleaned of aged cells.

In the second article published in Science, we are talking about atherosclerosis, one of the most common and harmful age–related diseases - cellular cleansing, as it turned out, reduces the likelihood of atherosclerotic vascular damage. Finally, more recently, researchers from the Salk Institute told Cell how they managed to reverse aging by turning on dormant embryonic genes in elderly mice. In fact, in the last work, the same method was used by which artificial analogues of embryonic stem cells are obtained – the famous induced stem cells, only with mice rejuvenation was performed not in cell culture, but immediately with the whole organism. As for artificial stem cells, they are still being studied very actively. Their differences from natural ones, apparently, should not be exaggerated so much, which means that they can also be used for clinical purposes.

But biomedical technologies are alive not only by stem cells. A huge amount of work here is devoted to restoring the mobility of paralyzed limbs, restoring the conductivity of damaged nerve pathways, and in general attempts to create a neurocomputer interface that would translate the signals of our brain into the language of electronic devices. For example, let's point to the experiments of neuroscientists from Stanford, the University of California at San Diego and Harvard, who managed to reconnect the retina with the brain, and a large project on teaching the spinal cord to behave independently, which is being carried out by researchers from Switzerland and St. Petersburg. As for the neurocomputer interface, the main achievements here are to increase the mobility and sensitivity of prosthetic hands.

In general, the biotechnological inventions of the outgoing year are striking in their diversity: there is an organosilicon anti-wrinkle remedy, robotic beetles, synthetic "nerves" printed on a 3D printer, and a stingray robot made of silicone, gold and living heart cells, and plants with improved photosynthesis.

Researchers are interfering with the very foundations of life – here, of course, we mean creating a synthetic organism with a minimal set of genes and rewriting the genetic code of bacteria. Modern technologies once again convince us that many "abstract" theories, which once looked like a product of pure knowledge, may well be useful in solving the most pressing, most everyday issues. Let's take the evolutionary theory – it not only helps us understand how bacteria and cancer cells develop resistance to drugs, it can be used to literally improve the drugs themselves, as demonstrated by researchers from Emory University.

Speaking of evolution. There are several big riddles in it that arouse invariably keen interest even among those who have nothing to do with biology: these are the extinction of dinosaurs, the origin of life and the origin of man. About dinosaurs, we can only say that they began to die out earlier than we thought, and an asteroid and/or volcanoes simply accelerated the decline of giant reptiles. As for the origin of life, let's recall a May article in Science, which says that RNA on ancient Earth could be obtained from simple chemical raw materials and without the help of enzymes.

Recall that according to modern ideas, life on our planet began with RNA molecules, which, like DNA, can store information in themselves, but, unlike DNA, RNA molecules are able to catalyze some chemical reactions and multiply without the help of proteins. Subsequently, RNA still had to give up the role of DNA as the "main molecule of life" - simply because DNA turned out to be more stable. Among the various reasons that led to the appearance of humans, another one appeared – a special antiviral protein that contributed to the appearance of new mutations in the primate genome and thereby stimulated their evolution. Subsequently, when the genus Homo began to master tools, a big role in its evolution was played by "kitchen knives" – that is, sharp stones with which it was possible to cut meat.

An article in Nature published in March says that chopping food literally changed the appearance of human ancestors: their head became lighter and they had lips, which, in turn, came in handy when it was time to speak. However, researchers from the University of Vienna and Princeton University believe that judging by the anatomy of the throat and mouth, even today's monkeys could well speak humanly, but they are prevented from mastering at least the rudiments of speech by a not fully developed brain. On the other hand, monkeys are too smart without talking. The fact that they make tools has been known for a long time; but moreover, it turned out that monkeys have been using them for centuries and that monkey tools are almost indistinguishable from those made by ancient people. Recent experiments with chimpanzees have shown that they are able to associate other people's wrong actions with other people's wrong thoughts, and observations of wild chimpanzees have made us wonder if they have the rudiments of culture – in the human understanding of it.

However, not only primates are distinguished by high intelligence: New Caledonian crows can also make tools – and in different ways – ordinary crows are able to read other people's thoughts, and ducklings, as it turned out, are capable of abstract thinking. In general, avian intelligence has traditionally been underestimated, and now birds are taking revenge; and if someone asks how such a large intelligence fits in such a small bird's head, then quite recently the efforts of neuroscientists managed to answer this question - the brain of birds, as it turned out, is filled with very small neurons, which in some species in total even more than primates.

If we evaluate intelligence by a social criterion, that is, by the ability to communicate with their own kind or with representatives of other species, then there are a lot of surprises waiting for us: octopuses who like to communicate, bumblebees who learn from each other, dogs who remember what their owners did, even if the owner's actions they have nothing to do with them. Well, what about the owners – that is, people? We've already talked about what we've learned about the human brain, but have we learned anything new about human psychology? Oh yeah. In February, an article was published in Current Biology on why a person is capable of killing on orders, in the fall in the Royal Society Open Science, researchers from Oxford reported that plane crashes are remembered for an average of only a week; finally, from an article in Psychological Science published in April, we learned about how a potential shortage of marital partners

makes you do risky things – even those of us who are not very risk-averse and who have had a family for a long time.

Modern psychology freely uses the methods of neurobiology (magnetic resonance imaging, etc.), which allows psychologists to get quite interesting results. So, the authors of the article in Neuropsychologia explained how we get a mystical experience – the secrets of the universe are revealed to us when the brain brakes are turned off.

With the help of MRI, we also managed to find out that it is pleasant to believe in God, and that lying literally changes the brain – by regularly practicing lies, we help the brain get used to the fact that we are lying, so that in the future it no longer bothers us about unpleasant emotions. If someone, after reading all this, plunges into a depressed state of mind about the imperfections of humanity and wants to disperse sadness and longing, then let them remember that, although happiness is not in money, it is still quite possible to buy it – you just need to know where to buy it.

There is a very large and important section of child psychology in psychological science, important also because, observing the development of emotions, cognitive properties and personality in general in a child, we better understand where our "adult" thoughts and feelings come from later. One of the most difficult topics here: the ratio in the personality of innate traits and those that came from communication with others, from parents, from the cultural context. It is worth noting here a study by psychologists from Northwestern University that language affects thinking from infancy; this means that the words heard help young children think - even those who do not know how to speak themselves yet.

If we want the child to learn the language faster, then you can turn to music for help: experts from the University of Washington believe that musical games help babies feel the rhythm of speech. (We add that if we are talking about games, it is better to give children not electronic gadgets, but some cubes - ordinary toys are more useful for the development of the child.) As for ethical norms, they seem to depend more on the cultural environment: young children behave quite selfishly, and the desire for justice begins to develop from the age of five; in general, as psychologists from Northwestern University and their Chinese colleagues have shown, cultural perception features manifest in children by the age of two. It's time to finish our review, although we haven't told you about a number of interesting things, like the influence of viruses on the climate or the unique ability of slow walkers to resist ionizing radiation. However, there is one topic that we cannot miss in any way – these are seals.

In the past year, we mostly wrote about wild cats: about how ocelot latrines in the forests of South America serve other mammals as something like a newspaper and a club, about why big cats have different brains, about how in ancient times small cats were domesticated twice, although the second time ended in nothing.

We had only one piece of news dedicated to domestic cats, but on an inescapable topic: researchers from the University of Sydney and the Waltham Center for Pet Nutrition once again tried to solve the riddle of the famous feline fastidiousness in food.

Portal "Eternal youth" http://vechnayamolodost.ru  09.01.2017

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