It's quite easy to forget that ideas that seem obvious to us today have been honed by collectives over centuries. smart people, and didn’t just appear. The fact that we take them for granted is just the tip of the iceberg interesting story. Let's dig deeper.
Awareness that animals may disappear
If you're walking along the beach and find an interesting fossil pebble, you immediately realize that it might belong to a long-extinct species. The idea that species are becoming extinct is so familiar to us that it is difficult to even imagine a time when people thought that everyone separate type creatures still live anywhere. People believed that God created everything - why would he create something that couldn't survive?
George Cuvier was the first person to ask this question. In 1796, he wrote an article on elephants, in which he described the African and Asian varieties. He also mentioned a third type of elephant, known to science only from its bones. Cuvier noted key differences in the jaw shape of the third elephant and suggested that this species must be completely separate. The scientist called it a mastodon, but where are the living specimens then?
According to Cuvier, “all these facts are in agreement with each other and do not contradict any other message, so it seems to me possible to prove the existence of a world that preceded ours and was destroyed as a result of some kind of catastrophe.” He did not stop only with this revolutionary idea. Cuvier studied the fossils of other ancient animals - coining the term "pterodactyl" along the way - and discovered that reptiles had once been the dominant species.
The first cells grown outside the body
If a biologist wants to conduct research on the inner workings of animal cells, it is much easier if those cells are not part of the animal at the time. Currently, biologists culture wide strips of cells in vitro, which makes the task much easier. The first person to try to keep cells alive outside the host's body was Wilhelm Roux, a German zoologist. In 1885, he placed part of a chicken embryo in a saline solution and kept it alive for several days.
Research using this particular method continued for several decades, but in 1907 someone suddenly decided to grow new cells in solution. Ross Harrison took embryonic frog tissue and was able to grow new nerve fibers from them, which he then kept alive for a month. Today, cell samples can be kept alive almost indefinitely - scientists are still experimenting with cell tissue from a woman who died 50 years ago.
Discovery of homeostasis
You've probably heard something about homeostasis, but in general it's very easy to forget how important it is. Homeostasis is one of the four essential principles of modern biology, along with evolution, genetics and cell theory. The main idea fits into a short phrase: organisms regulate their internal environment. But as is the case with others important concepts, which can be fit into a short and succinct phrase - objects with mass are attracted to each other, the Earth rotates around the Sun, there is no catch - this is a truly important understanding of the nature of our world.
The idea of homeostasis was first put forward by Claude Bernard, a prolific scientist in the mid-19th century who was kept awake by the fame of Louis Pasteur (even though they were friends). Bernard made serious progress in understanding physiology, despite the fact that his love for vivisection destroyed his first marriage - his wife rebelled. But the true importance of homeostasis - which he called the milleu interieur - was recognized decades after Bernard's death.
In a lecture in 1887, Bernard explained his theory this way: “A living body, although in need of environment, relatively independent of it. This independence from the external environment arises from the fact that in a living being the tissues are essentially separated from direct external influences and protected by a true internal environment, which consists in particular of the fluids circulating in the body."
Scientists who are ahead of their time often go unrecognized, but Bernard's other work was enough to cement his reputation. However, it took science almost 50 years to test, confirm and evaluate his most important idea. The entry about it in the Encyclopedia Britannica for 1911 says nothing at all about homeostasis. Six years later, the same article on Bernard calls homeostasis “the most important achievement of the era.”
First enzyme isolation
Enzymes are usually first learned about in school, but if you've been skipping class, let's explain: these are large proteins that help the flow of food. chemical reactions. In addition, they are used to make effective washing powder. They also provide tens of thousands of chemical reactions in living organisms. Enzymes are as important to life as DNA - our genetic material cannot copy itself without them.
The first enzyme discovered was amylase, also called diastase, and it's in your mouth right now. It breaks down starch into sugar and was discovered by French industrial chemist Anselme Payen in 1833. He isolated the enzyme, but the mixture was not very pure. For a long time, biologists believed that extracting a pure enzyme might be impossible.
It took almost 100 years for American chemist James Butchler Sumner to prove them wrong. In the early 1920s, Sumner began isolating the enzyme. His goals were so audacious that they actually cost him the friendship of many leading experts in the field who thought his plan would fail. Sumner continued and in 1926 isolated urease, an enzyme that breaks down urea into its chemical components. Some of his colleagues doubted the results for years, but eventually they too had to give in. Sumner's work earned him the Nobel Prize in 1946.
The assumption that all life has a common ancestor
Who was the first to suggest that all life evolved from one creature? You say: of course, Charles Darwin. Yes, Darwin developed this idea - in his "Origin of Species" he wrote the following: "There is a certain grandeur in this view of such life, with its various manifestations, which was originally embodied in several forms or in one." However, while we do not downplay Darwin's achievements, the idea of a common ancestor had been proposed decades earlier.
In 1740, the famous Frenchman Pierre Louis Moreau de Maupertuis proposed that "blind fate" produced a wide range of individuals, of whom only the most capable survived. In the 1790s, Immanuel Kant noted that this could refer to the primordial ancestor of life. Five years later, Erasmus Darwin wrote: “Would it be too bold to suppose that all warm-blooded animals are descended from one living thread?” His grandson Charles decided that there was no “too much” and suggested.
Invention of cell staining
If you've ever seen microscopic photographs of cells (or looked at them yourself), there's a pretty good chance they were stained first. Staining allows us to see parts of the cell that are not normally visible and generally increases the clarity of the picture. There are a bunch of different methods for staining cells, and this is one of the most fundamental techniques in microbiology.
The first person to tint a specimen for examination under a microscope was Jan Swammerdam, a Dutch naturalist. Swammerdam is best known for his discovery of red blood cells, but he has also made a career out of looking at everything under a microscope. In the 1680s, he wrote about the “colored liquors” of dissected worms, which “allow the internal parts to be better marked, since they are of the same color.”
Unfortunately for Swammerdam, this text was not published for at least another 50 years, and by the time of publication, Jan was already dead. At the same time, his fellow countryman and naturalist Antonie van Leeuwenhoek, independently of Swammerdam, came to the same idea. In 1719, Leeuwenhoek used saffron to stain muscle fibers for further examination and is considered the father of this technique.
Development of cell theory
“Every living creature is made up of cells,” this phrase is as familiar to us as “The Earth is not flat.” Today cell theory is taken for granted, but in fact it was beyond comprehension until the 19th century, another 150 years after Robert Hooke first saw cells under a microscope. In 1824, Henri Duroche wrote about the cell: “It is evident that it represents the basic unit of an ordered state; indeed, everything ultimately comes from the cell.”
In addition to the fact that the cell is the basic unit of life, cell theory also implies that new cells are formed when another cell divides into two. Duroce missed this part (in his opinion, new cells are formed inside their parent). The final understanding that cells divide to reproduce came from another Frenchman, Barthélemy Dumortier, but there were other people who made significant contributions to the development of ideas about cells (Darwin, Galileo, Newton, Einstein). Cell theory was created in small increments, much the same as modern science today.
DNA sequencing
Until his recent death, British scientist Frederick Sanger was the only living person to have received two Nobel Prizes. It was his work for the second prize that led to him being included on our list. In 1980 he received the top scientific prize together with Walter Gilbert, an American biochemist. In 1977, they published a method that allows one to determine the sequence of building blocks in a DNA chain.
The significance of this breakthrough is reflected in how quickly the Nobel committee awarded the scientists. Ultimately, Sanger's method became cheaper and simpler, and became the standard for a quarter of a century. Sanger paved the way for revolutions in the fields of criminal justice, evolutionary biology, medicine, and many others.
Virus discovery
In the 1860s, Louis Pasteur became famous for his germ theory of disease. But Pasteur's microbes were only half the story. Early proponents of the germ theory thought that all infectious diseases were caused by bacteria. But it turns out that colds, flu, HIV and other endless health problems are caused by something completely different - viruses.
Martinus Beijerinck was the first to realize that bacteria were not the only ones to blame. In 1898, he took juice from tobacco plants suffering from the so-called mosaic disease. Then I filtered the juice through a sieve so fine that it should have filtered out all the bacteria. When Beijerinck applied the juice to healthy plants, they still got sick. He repeated the experiment - and they still got sick. Beijerinck concluded that there was something else, perhaps a liquid, that was causing the problem. He called the infection vivum fluidum, or soluble living bacteria.
Beijerinck also picked up old English word“virus” and endowed it with a mysterious agent. The discovery that viruses were not liquid belongs to the American Wendell Stanley. He was born six years after Beijerinck's discovery and, apparently, immediately understood what needed to be done. Stanley shared the 1946 Nobel Prize in Chemistry for his work on viruses. Do you remember who you shared it with? Yes, with James Sumner for his work on enzymes.
Refusal of preformationism
One of the most unusual ideas in history was preformationism, once the leading theory about the creation of the baby. As the name suggests, the theory suggested that all creatures were pre-created - that is, their form was already ready before they began to grow. Simply put, people believed that miniature human body was inside every sperm or egg looking for a place in which to grow. This tiny man was called a homunculus.
One of the key proponents of preformationism was Jan Swammerdam, the inventor of the cell dyeing technique, whom we discussed above. The idea was popular for hundreds of years, from the mid-17th century until the end of the 18th.
An alternative to preformationism was epigenesis, the idea that life arises through a series of processes. The first person who put forward this theory against the background of his love for preformationism was Caspar Friedrich Wolf. In 1759, he wrote an article in which he described the development of the embryo from several layers of cells to a human being. His work was extremely controversial at that time, but the development of microscopes put everything in its place. Embryonic preformationism was far from dead in its infancy, but it was dead, pardon the pun.
Ten biggest achievements of the decade in biology and medicine Version of an independent expert
New high-throughput DNA sequencing methods – the “price” of the genome is falling
MicroRNA - what the genome was silent about
New high-throughput DNA sequencing methods – the “price” of the genome is falling
One of the founders of the famous Intel company, G. Moore, once formulated an empirical law that is still true: computer productivity will double every two years. The productivity of DNA sequencers, which are used to decipher the nucleotide sequences of DNA and RNA, is growing even faster than according to Moore’s Law. Accordingly, the cost of reading genomes is falling.
Thus, the cost of work on the Human Genome Project, which ended in 2000, amounted to $13 billion. New mass sequencing technologies that appeared later were based on the parallel analysis of many DNA fragments (first in microwells, and now in millions of microscopic drops). As a result, for example, decoding the genome of the famous biologist D. Watson, one of the authors of the discovery of the structure of DNA, which in 2007 cost $2 million, only two years later “cost” $100 thousand.
In 2011, the company "Ion torrent", which offered new method sequencing based on measuring the concentration of hydrogen ions released during the operation of DNA polymerase enzymes, read the genome of Moore himself. And although the cost of this work has not been announced, the creators of the new technology promise that reading any human genome should not exceed $1,000 in the future. And their competitors, the creators of another new technology, DNA sequencing in nanopores, already this year presented a prototype of a device on which, after spending several thousand dollars, you can sequence the human genome in 15 minutes.
Synthetic biology and synthetic genomics - how easy it is to become God
The information accumulated over half a century of development of molecular biology today allows scientists to create living systems that have never existed in nature. As it turns out, this is not at all difficult to do, especially if you start with something already known and limit your claims to such simple organisms as bacteria.
These days, the United States even hosts a special competition, iGEM (International Genetically Engineered Machine), in which student teams compete to see who can come up with the most interesting modification of common bacterial strains using a set of standard genes. For example, by transplanting into the well-known Escherichia coli ( Escherichia coli) a set of eleven specific genes, colonies of these bacteria, growing in an even layer on a Petri dish, can be made to consistently change color where the light falls on them. As a result, it is possible to obtain their unique “photographs” with a resolution equal to the size of the bacterium, i.e., about 1 micron. The creators of this system gave it the name “Koliroid”, crossing the species name of the bacterium and the name of the famous company “Polaroid”.
This area also has its own megaprojects. Thus, in the company of one of the fathers of genomics, K. Venter, the genome of a mycoplasma bacterium was synthesized from individual nucleotides, which is not similar to any of the existing mycoplasma genomes. This DNA was enclosed in a “ready” bacterial shell of killed mycoplasma and a working one was obtained, i.e. a living organism with a completely synthetic genome.
Anti-aging drugs - the path to “chemical” immortality?
No matter how many attempts have been made over thousands of years to create a panacea for aging, the legendary Makropoulos remedy has remained elusive. But progress is also appearing in this seemingly fantastic direction.
Thus, at the beginning of the last decade, resveratrol, a substance isolated from the skin of red grapes, produced a big boom in society. First, with its help, it was possible to significantly extend the life of yeast cells, and then of multicellular animals, microscopic nematode worms, fruit flies, and even aquarium fish. Then the attention of specialists was attracted by rapamycin, an antibiotic first isolated from soil streptomycete bacteria from the island. Easter. With its help, it was possible to extend the life not only of yeast cells, but even of laboratory mice, which lived 10-15% longer.
By themselves, these drugs are unlikely to be widely used to prolong life: rapamycin, for example, suppresses immune system and increases the risk of infectious diseases. However, active research is currently underway into the mechanisms of action of these and similar substances. And if this succeeds, then the dream of safe medicines ah for prolonging life may well become a reality.
The use of stem cells in medicine – we are waiting for a revolution
Today, the US National Institutes of Health Clinical Trials Database lists almost half a thousand studies using stem cells at various stages of research.
However, it is alarming that the first of these, concerning the use of nervous system cells (oligodendrocytes) to treat spinal cord injuries, was interrupted in November 2011 for an unknown reason. After this, the American company Geron Corporation, one of the pioneers in the field of stem biology, which conducted this research, announced that it was completely curtailing its work in this area.
However, I would like to believe that medical use Stem cells with all their magical capabilities are just around the corner.
Ancient DNA - from Neanderthals to plague bacteria
In 1993, the film “Park” was released Jurassic", in which monsters walked on the screen, recreated from the remains of DNA from the blood of dinosaurs preserved in the stomach of a mosquito immured in amber. In the same year, one of the largest authorities in the field of paleogenetics, the English biochemist T. Lindahl, stated that even under the most favorable conditions, DNA older than 1 million years cannot be extracted from fossil remains. The skeptic was right - dinosaur DNA remains inaccessible, but the advances in technical improvements in methods for extracting, amplifying and sequencing younger DNA over the past decade have been impressive.
To date, the genomes of a Neanderthal, a recently discovered Denisovan, and many fossil remains have been read in whole or in part. Homo sapiens, as well as mammoth, mastodon, cave bear... As for the more distant past, DNA from plant chloroplasts, whose age dates back to 300-400 thousand years, and DNA from bacteria dating back to 400-600 thousand years were studied.
Among studies of “younger” DNA, it is worth noting the decoding of the genome of the influenza virus strain that caused the famous “Spanish flu” epidemic in 1918, and the genome of the plague bacterium strain that devastated Europe in the 14th century; in both cases, the materials for analysis were isolated from the buried remains of those who died of the disease.
Neuroprosthetics – human or cyborg?
These achievements belong more likely to engineering rather than biological thought, but this does not make them look any less fantastic.
At all simplest type neuroprosthesis - an electronic hearing aid - was invented more than half a century ago. The microphone of this device picks up sound and transmits electrical impulses directly to the auditory nerve or brain stem - thus, even patients with completely destroyed structures of the middle and inner ear can be restored to hearing.
The explosive development of microelectronics over the last ten years has made it possible to create such types of neuroprostheses that it is time to talk about the possibility of soon turning a person into a cyborg. This is an artificial eye, operating on the same principle as a hearing device; and electronic suppressors of pain impulses through the spinal cord; and automatic artificial limbs, capable of not only receiving control impulses from the brain and performing actions, but also transmitting sensations back to the brain; and electromagnetic stimulators of brain areas affected by Parkinson's disease.
Today, research is already underway regarding the possibility of integrating different parts of the brain with computer chips to improve mental abilities. Although this idea is far from being fully realized, video clips showing people with artificial hands confidently using a knife and fork and playing foosball are amazing.
Nonlinear optics in microscopy – seeing the invisible
From a physics course, students firmly grasp the concept of the diffraction limit: with the best optical microscope it is impossible to see an object whose dimensions are less than half the wavelength divided by the refractive index of the medium. At a wavelength of 400 nm (violet region of the visible spectrum) and a refractive index of about unity (like air), objects smaller than 200 nm are indistinguishable. Namely, this size range includes, for example, viruses and many interesting intracellular structures.
Therefore in last years Nonlinear and fluorescent optics methods, for which the concept of diffraction limit is not applicable, have been widely developed in biological microscopy. Nowadays, using such methods it is possible to study in detail the internal structure of cells.
Designer proteins - evolution in vitro
As in synthetic biology, we are talking about creating something unprecedented in nature, only this time not new organisms, but individual proteins with unusual properties. This can be achieved using both improved computer modeling methods and “in vitro evolution” - for example, selection of artificial proteins on the surface of bacteriophages specially created for this purpose.
In 2003, scientists from the University of Washington, using computer structure prediction methods, created the Top7 protein, the world's first protein whose structure has no analogues in living nature. And based on the known structures of the so-called “zinc fingers” - elements of proteins that recognize sections of DNA with different sequences, it was possible to create artificial enzymes that cleave DNA at any predetermined location. Such enzymes are now widely used as tools for genome manipulation: for example, they can be used to remove a defective gene from the genome of a human cell and force the cell to replace it with a normal copy.
Personalized medicine – getting gene passports
The idea that different people get sick and should be treated differently is far from new. Even if we forget about different gender, age and lifestyle and do not take into account genetically determined hereditary diseases, our individual set of genes can still uniquely influence both the risk of developing many diseases and the nature of the effect of drugs on the body.
Many have heard about genes, defects in which increase the risk of developing cancer. Another example concerns the use of hormonal contraceptives: if a woman carries the Leiden gene for factor V (one of the proteins of the blood coagulation system), which is not uncommon for Europeans, her risk of thrombosis sharply increases, since both hormones and this gene variant increase blood clotting .
With the development of DNA sequencing techniques, it has become possible to compile individual genetic health maps: it is possible to determine which gene variants are known to be associated with diseases or responses to medications, are present in the genome of a particular person. Based on such an analysis, recommendations can be made on the most appropriate diet, necessary preventive examinations and precautions when using certain medications.
MicroRNA - what the genome was silent about
In the 1990s. The phenomenon of RNA interference was discovered - the ability of small double-stranded deoxyribonucleic acids to reduce gene activity due to the degradation of messenger RNAs read from them, on which proteins are synthesized. It turned out that cells actively use this regulatory pathway, synthesizing microRNAs, which are then cut into fragments of the required length.
The first microRNA was discovered in 1993, the second only seven years later, and both studies used a nematode Caenorhabditis elegans, which now serves as one of the main experimental objects in developmental biology. But then discoveries rained down like from a cornucopia.
It turned out that microRNAs are also involved in embryonic development humans, and in the pathogenesis of cancer, cardiovascular and nervous diseases. And when it became possible to simultaneously read the sequences of all the RNAs in a human cell, it turned out that a huge part of our genome, which was previously considered “silent” because it did not contain protein-coding genes, actually serves as a template for reading microRNAs and other non-coding RNAs.
D. b. n. D. O. Zharkov (Institute of Chemical
biology and fundamental medicine
SB RAS, Novosibirsk)
Recent advances in biology have led to the emergence of completely new directions in science. Thus, the establishment of the molecular nature of the gene served as the basis for genetic engineering - a set of methods that make it possible to construct pro- and eukaryotic cells with a new genetic program. On this basis, industrial production of antibiotics, hormones (insulin), interferon, vitamins, enzymes and other biologically active drugs has been established.
Among the achievements of biology we can note the description large number types of living organisms existing on Earth, the creation of cellular, evolutionary, chromosomal theories, deciphering the structure of proteins and nucleic acids, etc. In practice, this contributed to increasing the efficiency of agricultural production, the development of medicine, biotechnology, and the creation of the foundations for rational environmental management.
Those who follow achievements of molecular biology, must have already become accustomed to the fact that in this young science, which has entered only the third decade of its existence, major discoveries are made often, even very often. Just 17 years ago, the American James Watson and the Englishman Francis Crick proposed a hypothesis about the structure of the DNA molecule, which, in their opinion, which was not shared by most biologists at that time, was the keeper of genetic information. Very soon, in a fantastically short time, the opinion of Watson and Crick that DNA actually carries a record of all the genes of an organism was proven experimentally. By the early sixties, it became clear that genetic information from DNA molecules is transferred to RNA molecules that are similar in structure. The latter connect to special cell structures - ribosomes, in which protein synthesis occurs. A little earlier, G. Gamow (USA), F. Crick and others created a logically complete model of the genetic code. The most important thing was that it was strictly indicated why the cell needs genetic information (synthesis of specific proteins, which determine the properties of life and the ability to carry out various vital functions). It was also shown how individual elements of the DNA molecule (according to Gamow, with which everyone agreed, triplets of nucleotides located along the DNA chain) encode the structure of proteins synthesized in ribosomes.
Few people expected - even among very insightful geneticists - that already in 1961 Crick and his three assistants would “crack down” on the problem of the general nature of the genetic code. True, the path to deciphering the composition of individual triplets encoding amino acids was opened by the work of M. Nirenberg and D. Mattei, reported in Moscow in the summer of the same 2000. And it was absolutely difficult to imagine that just two and a half years later, the Americans M. Nirenberg and F. Leder would propose a method that would make it possible to find out the exact structure of all 64 gene code words. Within a year, geneticists knew the hereditary alphabet of nature.
But solving these problems did not increase our knowledge about the exact structure of the gene, the exact structure of the molecules of individual information and transport RNAs. In 1964-1965, Holly in the USA and A. Baev in the Russian Federation deciphered the first, smallest molecules serving genetic secrets - transport RNA molecules. In 1967, in the laboratory of A. Kornberg in the USA, after many years of unsuccessful attempts, it was possible to synthesize a workable DNA molecule of phage 0X174. A year later, G. Korana (an Indian who moved to the USA), in an ingenious experiment, managed to synthesize the first gene for yeast transfer RNA. And now, just a year later, a pure gene has been isolated from living DNA molecules!
Paradoxically, this experiment, grandiose in its design, execution and consequences for science, was not an end in itself. Beckwith, a well-known expert in the field of the molecular basis of the implementation of genetic information, in the preface indicates the main goal that he and his colleagues pursued when starting their work. It was important for them to find clues to resolving the long-standing dispute about when gene activity is regulated. There were two approaches. According to the first, the ten itself (that is, a section of DNA with a strictly defined nucleotide sequence) can be an arena of regulation. In this case, messenger RNA will be copied from activated genes, but such copying will not occur from repressed genes.
Thus, Biology is a rather young, but quite progressive science, quite useful for humans.
MEDICINE IN THE XX CENTURY
v 1901- Landsteiner discovered blood groups, the beginning of blood transfusion.
v 1904 - Nobel Prize in the field of physiology and medicine was awarded to Ivan Petrovich Pavlov for the discovery of conditioned reflexes.
v 1906 - first cadaveric cornea transplant.
v 1910 - Thomas Morgan discovered chromosomes - the organelles of heredity.
v 1912- Banting and Best discovered insulin and the cause of diabetes.
v 1926 - Möller discovered the mutagenic effects of radiation and chemical substances.
v 1936 - the first enzymes were obtained in a crystalline state.
v 1944 - Oswald Avery and McLean McCarthy proved that isolated DNA is inserted into the genome of bacteria, changing their phenotype.
v 1951 - first coronary bypass surgery (coronary bypass).
v 1953 - James Watson and Francis Crick discovered the double helix of DNA.
v 1955 - first kidney transplant.
v 1956 - first coronary angioplasty.
v 1961 - Marshall Nirenberg deciphered the genetic code (dictionary) of DNA. The first hematogenous stem cell transplants to save doomed patients.
v 1964 - Charles Yanovsky confirmed the linear correspondence of genes and proteins of bacteria.
v 1967 - first heart and liver transplant.
v 1969 - a group of researchers from Harvard medical school isolated the first human gene.
v 1974 - Stanley Cohen and Herbert Boyer transplanted a frog gene into bacterial cell. The beginning of genetic engineering.
v 1976 - the first biotechnology company Genentech was created; transplantation of human genes into microbial cells began for the industrial production of insulin, interferon and other useful proteins.
v 1980 - Martin Klein created the first transgenic mouse by transferring a human gene into a fertilized mouse egg.
v 1982 - genetically engineered insulin produced by bacteria is approved for use in medicine.
v 1983 - the polymerase chain reaction (a technique for repeatedly cloning short DNA chains) was discovered - it became possible to simultaneously study the work of many genes.
v 1985 - the technique of “genetic fingerprinting” of DNA began to be used in world forensic science.
v 1985 - first fetal nerve tissue transplants to treat Parkinson's disease.
v 1988 - the first patent for a genetically modified animal was issued.
v 1990 - start of work on the international Human Genome project.
v 1997 - the first mammal was cloned - a sheep named Dolly; This was followed by successful experiments in cloning mice and other mammals.
v 1997-1998 - isolation of human embryonic stem cells in the form of immortal lines.
v 1998 - creation of methods for simultaneous recording of the activity of 1000-2000 genes in the genome of humans and mammals.
v 1999-2000 - complete decoding of the genome of 10 bacteria and yeast. Identification and establishment of the location of half of the genes in human chromosomes.
v 2001 - complete decoding of the human genome
CLONING CHRONOLOGY
v 1883 - discovery of the egg by the German cytologist Oskar Hertwig (Hertwig, 1849-1922).
v 1943 - Science magazine reported the successful fertilization of an egg “in vitro”.
v 1953 - R. Briggs and T. King reported the successful development of the “nucleotransfer” method - transfer of a cell nucleus into giant eggs of the African clawed frog “xenopus”.
v 1973 - Professor L. Shettles of Columbia University in New York announced that he was ready to produce the first “test tube baby”, which was followed by categorical prohibitions from the Vatican and the Presbyterian Church in the USA.
v 1977 - the publication of a series of articles about the work of Oxford University zoology professor J. Gurdon, during which more than fifty frogs were cloned, ended. The nuclei were removed from their eggs, after which the nucleus of a somatic cell was transplanted into the remaining “cytoplasmic sac”. For the first time in the history of science, the place of the haploid nucleus of an egg with a single set of chromosomes was replaced by the diploid nucleus of a somatic cell with a double number of carriers of genetic information.
v 1978 - the birth of Louise Brown, the first test-tube child, in England.
v 1981 - Shettles receives three cloned human embryos, but stops their development.
v 1982 - Karl Ilmensee from the University of Geneva and his colleague Peter Hoppe from the Jackson Laboratory in Bar Harbor, Maine, where mice have been bred since 1925, obtained gray pups by transferring the nuclei of cells of a gray embryo into the cytoplasm of an egg obtained from a black female , after which the embryos were transferred into white females, who bore offspring. The results were not replicated in other laboratories, leading to Ilmensee being accused of falsification.
v 1985 - on January 4, in a clinic in north London, a girl was born to Mrs. Cotton - the world's first surrogate mother who was not a biological mother (that is, “Baby Cotton,” as the girl was called, was not conceived from Mrs. Cotton’s egg). A parliamentary ban was passed on experiments with human embryos older than fourteen days.
v 1987 - specialists from the John Washington University, using a special enzyme, were able to divide the cells of a human embryo and clone them to the stage of thirty-two cells (blasts, blastomeres), after which the embryos were destroyed. The American administration has threatened to deprive laboratories of subsidies from federal funds if such experiments are carried out in them.
v 1996 - On March 7, the journal Nature published the first article by a team of authors from the Roslin Institute in Edinburgh, who reported the birth of five lambs obtained without the participation of a ram: the nuclei of a culture of embryonic cells obtained from another embryo were transferred into the cytoplasmic sacs of the eggs. The Bill Clinton administration reaffirms its intention to withhold federal funds from anyone who intends to experiment with human embryos; Thus, a researcher from the University of Washington who carried out the analysis of the sex of the embryo and the analysis of defective genes at the eight-cell stage was deprived of subsidies.
v 1997 - February 27, "Nature" placed on its cover - against the background of a microphotograph of an egg - the famous sheep Dolly, born at the same Roslyn Institute in Edinburgh. At the end of June, Clinton sent a bill to Congress that would prohibit “the creation of a human being by cloning and nuclear transfer of somatic cells.”
v 1997 - at the very end of December, Science magazine reported the birth of six sheep obtained using the Roslyn method. Three of them, including Polly the sheep, carried the human gene for “factor IX” (“factor 9”), or a hemostatic protein, which is necessary for people suffering from hemophilia, that is, incoagulability of the blood.
v 1997 - Michael Smith’s book “Clones” is published in the USA, which talks about the cloning of people in underground tunnels around Los Angeles (see “Knowledge is Power”, 1998, no. 4).
v 1998 - Chicago physicist Sid announces the creation of a laboratory for human cloning: he claims that he will not end up with clients.
v 1998, early March - French scientists announced the birth of a cloned heifer.
v 1999. Dutch scientists intend to clone a mammoth. To do this, they use genetic material from a prehistoric mammal recently found in Siberia that died 20,380 years ago.
v 2000. A calf cloned from the cell of an already cloned bull was born in the laboratory of the Kagoshima Prefectural Institute of Agriculture. This calf thus became the first animal of the second generation of clones of relatively large mammals.
v 2000. British scientists who cloned Dolly the sheep created five piglets using the same method.
v 2001. American scientists declare the fundamental possibility of human cloning. The House of Lords of the British Parliament, after many hours of debate, approved a bill allowing the cloning of human embryos
CHRONICLE OF DISCOVERIES IN CHEMISTRY
v 2500 - 2000 BC e. Penetration of copper from the East to Europe. In Babylon, scales were invented - a tool for measuring the amount of gold and other materials. The prototype for them was the yoke of a heavy loader.
v 2000 - 1500 BC e. IN Egyptian pyramids samples of glass and malleable iron were found.
v 1300 - 1000 BC e. IN Ancient Greece copper, iron, tin, lead, the hardening of steel and the effect of manure as fertilizer are known.
v 1st century BC e. In the poem “On the Nature of Things” by Lucretius Cara, invisible atoms are contrasted with non-existent gods, with the help of which all the diversity of phenomena in the surrounding world is explained, including winds and storms, the spread of odors, evaporation and condensation of water.
v 700 - 1000 The Arab alchemist Jabir ibn Hayyan and his followers, as a result of unsuccessful attempts to transform base metals into gold, used crystallization and filtration to purify chemical substances; described the preparation of sulfuric, nitric, acetic acids and aqua regia (indicated its ability to dissolve gold); prepared silver nitrate, sublimate, ammonia and white arsenic (arsenic acid).
v 1000 - 1200 In The Book of the Scales of Wisdom, the Arab scientist Al-Kazini gives the specific gravities of 50 different substances. In the “Book of Secrets” Abu ar-Razi for the first time classifies all substances into earthy (mineral), plant and animal; the calcination (roasting) of metals and other substances, dissolution, sublimation, melting, distillation, algamation, condensation, etc. are described.
v 1280. Arnaldo of Villanovan described the preparation of essential oils.
v 1300 - 1400 monk Berthold Schwarz is credited with the invention of gunpowder (in Europe). (In China, gunpowder was known at the beginning of our era).
v 1452 - 1519 The great Italian artist Leonardo da Vinci, by burning a candle under a vessel overturned over water, proves that during combustion the air is consumed, but not all.
v XVI century Alchemist Vasily Valentin in his treatise “The Triumphal Chariot of Antimony” described hydrochloric acid, antimony, bismuth (preparation and properties); ideas have been developed that metals consist of three “principles”: mercury, sulfur and salt.
v 1493 - 1541 Paracelsus transforms alchemy into iatrochemistry, believing that the main task of chemistry is to serve medicine by producing medicines. From him comes the first, repeatedly repeated observation that combustion requires air, and metals, when converted to scale, increase their weight.
v 1556. The work of G. Agricola “12 books on metals” summarizes information about ores, minerals and metals; metallurgical processes and the intricacies of mining are described in detail; The taxonomy of metals according to external characteristics is given.
v 1586 - 1592 G. Galileo designed hydrostatic balances for determining the density of solids (1586), and invented a thermometer (1592).
THE ORIGIN OF SCIENTIFIC CHEMISTRY
v 1660 - 65 R. Boyle in the book “The Skeptical Chemist” formulated the main task of chemistry (the study of the composition of various bodies, the search for new elements), developed the concept of “chemical element” and emphasized the importance of the experimental method in chemistry. He introduced the term “analysis” in relation to chemical research, established the inverse proportionality of air volume to pressure, and used indicators to determine acids and bases.
v 1668. O. Tahenius introduced the concept of salt as a product of the interaction of an acid with an alkali.
v 1669. H. Brandt isolated phosphorus as a product of the distillation of urine (the first dated discovery of the element).
v 1675. N. Lemery defined chemistry as the art of “separating various substances contained in mixed bodies" (mineral, plant and animal).
v 1676. E. Marriott expressed the dependence of air volume on pressure.
v 1707. I. Betger received white phosphorus.
v 1721. I. Henkel obtained metallic zinc.
v 1722. F. Hoffman described the production of hydrogen sulfide.
v 1723. G. Stahl proposed the theory of phlogiston as the material principle of flammability.
v 1724. D. Fahrenheit discovered the dependence of the boiling point of water on pressure and the phenomenon of supercooling of water.
v 1730 - 33 R. Reaumur invented the alcohol thermometer (1730). He showed that solutions of different compositions have different densities (1733).
v 1735. G. Brandt discovered cobalt.
v 1741 - 50 M.V. Lomonosov defined the element (atom), corpuscle (molecule), simple and mixed substances and began developing his corpuscular theory (1741). Formulated the basic principles of the molecular kinetic theory of heat (1744). Discovered the law of conservation of mass of substances (1745). Observed the phenomenon of passivation of metals in conc. HNO3
v 1751. A. Kronstedt discovered nickel.
v 1757. D. Blake showed that carbon dioxide is released during fermentation.
v 1763. M. V. Lomonosov outlined the fundamentals of mining and assay art, described methods for obtaining metals from ores.
v 1766. G. Cavendish discovered hydrogen.
v 1768. A. Baume invented a device for determining the densities of liquids - a hydrometer.
v 1772. D. Rutherford discovered nitrogen.
v 1772 - 73 J. Priestley discovered hydrogen chloride, “laughing gas” (N 2 O) (1772), oxygen (“dephlogisticated air”), and described the properties of ammonia (1773).
v 1774. A. Lavoisier suggested that atmospheric air has complex composition. K. Scheele discovered manganese, barium, and described the properties of chlorine.
v 1775 - 77 A. Lavoisier (independently of J. Priestley) discovered oxygen, described its properties, and formulated the foundations of the oxygen theory of combustion.
v 1778 - 81 K. Scheele discovered molybdenum, tungsten; received glycerin, lactic acid, hydrocyanic acid and acetaldehyde.
v 1781. G. Cavendish showed that the combustion of hydrogen produces water.
v 1782. J. Müller von Reichenstein discovered tellurium.
v 1785. T. E. Lovitz discovered the phenomenon of adsorption by charcoal from solutions.
v 1787. A. Crawford and W. Cruickshank discovered strontium. J. Charles established an equation for the dependence of gas pressure on temperature.
v 1789. M. Klaproth discovered zirconium and uranium.I. Richter formulated the law of equivalents.
v 1794. Yu. Gadolin discovered yttrium, which marked the beginning of the chemistry of rare earth elements.
v 1796. S. Tennart and W. Wollaston proved that diamond consists of carbon.
v 1797. L. Vauquelin discovered chromium.
v 1798. T. E. Lovitz introduced the concept of a supersaturated solution.
v 1800. W. Nicholson and A. Carlyle carried out the electrolysis of water.
