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  • Liquid gold organisms

    2Not many people get organic substances in pure form (or in the form of homogeneous mixtures) are already in antiquity. Fats and oils, no doubt, are among their number. Therefore, their names are in all languages simple native, although the chemists call them also lipids (from the Greek “liposome” – fat). To detect them was easy because they occur in all living organisms, and often in large numbers. Nature took care of animals and plants, providing them with supplies of fuel for cold and hungry days. Animals put this fuel, mainly around the internal organs and under the skin to fat deposits at the same time served as a shock-absorbing cushion shocks and heat insulator. Other animals also have not forgotten either himself or his offspring. Those who lay their eggs, or caviar, to supply embryos and larvae necessarily include a variety of lipids in the yolk. Plants that produce seeds, also supply the germ oils. Lipids are not only fuel but also the raw material for production of active molecules, and building material for body cells, and storage of vitamins – in general, it is difficult to do without them.

    Not able to refuse the use of lipids in food and old people – it helped them survive the ice age, famine years and travel across continents. Monuments not only fertility, but fat can be called Venus figurines nanotechnology Neolithic carved by ancient sculptors.

    However, worship times, and resentment gave way to apprehension. The Old Testament forbade have internal fat of animals – it was supposed to be sacrificed. We have declared war on body fat – just look at the popular women’s and health magazines. They do not prohibit, but advised not to have a lot of fat pets, and promote useful lipids of fish and marine invertebrates of shrimp, sea cucumber, and others. People who eat plenty of seafood, rarely suffer from cardiovascular and other diseases than those whose diet contains a lot of meat and dairy dishes. Nutritionists believe that the whole matter of fat. It would be nice if polyunsaturated fatty acids dovozili seafood to continental cities unoxidised, but, unfortunately, in the air, they quickly and easily oxidized. People living far from the sea, it is necessary to diversify and improve fat menu, lard, nuts and seeds, eggs, birds, fish roe or grape snails and of course, oil.

    3Modern technology, who know what elements and quantitative analysis, have engaged in fats and oils in the late XVIII century. Antoine Laurent Lavoisier found that these substances are composed mainly of carbon and hydrogen. After that, it became clear why fats contain more energy per unit weight than carbohydrates – the first less oxidized. Karl Scheele discovered that fats contained glycerin. Owner lipidologii Michel Eugène Chevrel since 1811 identified several fatty acids – from oil to stearic acid. In 1812 he opened in gallstones cholesterol and fats in the divided Unsaponifiable and saponificable which are esters of fatty acids and glycerol. In 1823 came his essay “Chemical studies of animal fats.”

    In 1884 the English physician John Tudikum published a book “Guide to the chemical composition of the brain”, which wrote that the phospholipids (phosphatides) are the soul of any chemical bioplasm, animal or plant. They are able to perform various functions due to the fact that combine highly contrasting properties. Tudikum explained the universality of the phospholipids of their ability to form colloids, and colloid chemistry had just evolved, and she waited for solving the mystery of life.

    In the first half of the XIX and XX century fats or their derivatives were separated, given the different solubility in organic solvents. These methodologies were not accurate, and German scientists called lipidologiyu dirty chemistry. Only 50 years of XX century, chemists have learned to separate the lipids with chromatographic methods, which enabled them to describe systematically and reliably identify.

    Two functions of fats, fuel and construction, for a long time obscured the rest. First, scientists realized that fats are the fuel. Directly in turn, give energy, fatty acids are involved – the hydrocarbon tails, similar to the molecules of gasoline and kerosene, only longer and with acid-head (Figure 1). And for transport and storage in adipose tissue fatty acids coupled to a hydrophilic molecule of glycerol. These are called neutral fats, or triglycerides. Along with proteins and other lipids, they form a transport form – lipoproteins, which are located on the periphery of the polar groups, and in the center – fat tails.

    Fat, in contrast to carbohydrates, – long-play fuel. Prolonged stress, exhausting physical work a person begins to use less carbohydrates and more lipids. When work is finished or the marathon run, the chambers are beginning to enter fats obtained from food and re-synthesized. Stockpiles are not always pleased with their owners, and the struggle with excess – an exhausting exercise, but popular.

    One of the most important developments in physiology in recent years – the opening of the peptide hormone leptin, which is responsible for fat deposition and appetite. It regulates not quick reaction to saturation and slow – the overall amount of adipose tissue. When pantries are full of body fat cells of adipose tissues (adipocytes) and overblown generate a lot of leptin. It binds to receptors in the hypothalamus (if they are in the order), that produces some other substance, and is not hungry. This fat is not delayed, and fatty acids are oxidized rapidly. Leptin increases within a few hours after a meal in rodents and after several days of abundant food in humans, but decreases for several hours of fasting in both.

    Ob gene is leptin, discovered in 1994. Mice homozygous for the mutant gene, obese and binge-eating, spending little energy, hard to bear the cold, were often fruitless.

    Injections of leptin lead only to a decrease in adipose tissue, muscle and internal organs without atrophy. Obese regulation is violated. The level of leptin in their blood increased, but the function of the brakes it does not perform, and I’m hungry anyway. Probably, appetite control and other regulators. Nevertheless, in 1998, reported the successful treatment of leptin ozhirevshih mice.

    Fuel – is certainly important, but the lipids are needed for the body and other problems. One of them – the formation of external and internal cell membranes. The tails of lipid molecules do not interact with the water, gather together, unite the ranks, turning his head toward the water, and form a film (Fig. 2). This is done not only triglycerides but also the polar phospholipids, carry negatively charged phosphate group (Fig. 3), and cholesterol and other substances. Cholesterol though not related to lipids in the strict sense, but is usually seen with them. It gives the necessary rigidity of the membranes.

    In disputes about how to begin life, lipids occupy a special place. Until molecules floating freely in open water, talking about life and the organisms do not have to. When the membrane appeared, they separated the contents of cells from the outer space, inside began to accumulate the necessary ions and small molecules whirled cycles of reactions, and life arose. Several important steps in its evolution was associated with membranes, which divided the cells into compartments. Hereditary material segregated and formed a nucleus having organelles – mitochondria, chloroplasts, lysosomes, Golgi apparatus, endoplasmic reticulum. Supplied to all these economies are called eukaryotic cells – have this kernel.

    The membranes made of lipids and proteins, perform several functions. They regulate the penetration of substances into the cell and back, and transmit signals that are responsible for conducting nerve impulses, energy production in mitochondria and chloroplasts. For the work of membrane proteins is very important to lipid environment, so it is carefully regulated. When the rising or falling temperature, the properties of the membrane are also changing: there is a phase transition. Therefore, to life in cold water, lipid composition have to adjust to the membrane does not become too rigid. With this and the associated large number of polyunsaturated fatty acids in marine animals.

    In the 70 years scientists have learned to do from the lipids of microscopic bubbles and fill them with stuffing, such as medicine. Such capsules called liposomes – fatty calves. They can be equipped with molecules that target certain cells, and they will deliver the stuffing only there. And you can do from liposomes cosmetic cream to enter into the skin useful for her substance.

    Lipids and related substances on them are also present in the nucleus. Some of them (especially cardiolipin (Fig. 4), and cholesterol) are associated with DNA and are involved in the regulation of genes. The composition of these lipids varies depending on the activity of the genome, the phases of the cell cycle transition of DNA from supercoiled to relaxed form, as well as pathology – when a cell becomes malignant.

    This is just one example of the involvement of lipids in the information processes. Another, much more famous – conducting a nerve impulse spikes of neurons. Supporting this process in the nervous tissue and especially in the brain involved in many complex and interesting lipids: sphingomyelin, cerebrosides, gangliosides, glycolipids, and others. However, the membrane conduct and other signals. Thus, the flow of calcium into the muscle cells start to diminish through the membrane proteins in the cell are transmitted hormonal messages. The work of all these and many other mechanisms depends on the composition of lipids

    Published on October 15, 2012 · Filed under: Bioscience, Diagnostics, DNA;
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