Structure of molluscum contagiosum. gastropods

Mollusks are found almost everywhere on Earth - in marine and fresh waters, on land, in the oceans - up to maximum depths, in the mountains - to the line of eternal snows. There are no shellfish only in sandy deserts. Now on the globe there are at least 130 thousand species of mollusks, and the largest number of species lives in the tropics. Molluscs are divided into seven classes: gastropods, monoplacophores, armored, groove-bellied, bivalves, spadefoots and cephalopods.
Mollusks are surprisingly different both in appearance and lifestyle. Sedentary pearls and swift squids, small fragile ambers and giant octopuses are all representatives of mollusks.
Most mollusks have in common the presence of an outer shell built from calcium carbonate and a protein substance. The shell consists of three layers: organic, porcelain and mother-of-pearl. A thin organic layer protects it from the effects of water, the porcelain-like layer takes on the main mechanical load.

The inner layer - mother-of-pearl - consists of thin calcareous plates overlapping each other. It was the mother-of-pearl of bivalve mollusks that people have used since ancient times for the manufacture of various jewelry.
On the one hand, the shell quite reliably protects the body of the mollusk from predators and water loss, on the other hand, it hinders their evolution. The shell mollusk reacts to all stimuli in the same way - it is drawn into the shell. He does not need to think about what to do with irritations of a different nature - there is only one reaction. Since there is no need to think, it means that there is no need to improve the nervous system, there is no need for complex behavioral reactions. Once the shell "created" the mollusks, and later it began to slow down their development. Therefore, it is not surprising that among modern molluscs we can observe all stages of the disappearance of the shell - from snails with a well-developed shell to slugs, in which the remains of the shell are preserved in the form of a plate lying in the thickness of the mantle. In slugs, the brain has a more complex structure, and their behavior is more diverse than in shell snails.
The shell may consist of one piece (classes of monoplacophorans and gastropods, or snails), of two more or less identical valves (class of bivalves, or shells), of eight individual plates (class of shells).
The body of the mollusk is covered with a special skin fold - the mantle. The space between the mantle and the body is called the mantle cavity.
The shape of the body of mollusks is determined by the shape of the shell, and it is different for different classes of mollusks. So it is impossible to derive a single body structure scheme for all mollusks. They have the following body parts: head, leg and torso. But bivalves do not have a head, and cephalopods do not have legs, instead of it they have tentacles.
The shell and body of most gastropods are twisted into a spiral. In bivalves, the shell consists of two valves that can open and close. Some mollusks do not have an outer shell at all, like the slugs, pests in our gardens. Instead of a shell, they have a thin calcareous plate covered with a mantle.
Gills and some sense organs are located in the mantle cavity of mollusks, openings of the kidneys, hindgut and reproductive apparatus open into it. Mollusks are the first representatives of the animal to have a liver.
The substance for the construction of the shell is secreted by special cells of the mantle. As the mantle grows, so does the size of the shell. Water constantly circulates in the mantle cavity of molluscs and washes the gills, bringing them oxygen. To create a continuous flow of water in the mantle cavity, there are two more holes: inlet and outlet siphons. Fresh water enters the cavity through the inlet siphon, and waste water is ejected through the outlet.
Mollusks have another important feature - they all have a kind of organ called the radula, or grater. The radula is located in the mouth of the mollusk and is, figuratively speaking, a combination of tongue and teeth: at the bottom oral cavity a kind of cartilage is located on which rows of teeth of various shapes are located for grinding food. In herbivorous molluscs, the teeth of the radula are mostly small, the teeth of predators are larger, often in the form of a gaff or dagger. Some sea snails have a channel inside their teeth through which poison flows from a special poisonous gland.
Those who are fond of aquariums appreciate ampoule snails (they belong to the class of gastropods) for their ability to clean glass from algae with a grater.
Mollusks breathe either oxygen dissolved in water with the help of one or two gills, or air with the help of a single lung. The so-called primary water mollusks, whose ancestors never left the water, breathe with gills. When animals move to land, the gill disappears, and it is replaced by a lung located in the mantle cavity. But life does not stand still, and some shellfish leave the land again.
Mollusks have long served man not only as food and a means of decoration. In Oceania, Africa and America, mollusk shells were even used as money. The natives of the Pacific Islands make multi-meter cords from nassa snail shells strung on them. Africa even in the 20th century. “kauri” money from the shells of cyprian snails was also common. AT North America abalone shells were used as money, and the Indians embroidered their leather wampum belts with pieces of bussicon snail shells. These were not simple belts - among the Indians they served as documents.

bivalves

Shellfish

The class of shellfish, or chitons, is a purely marine group. These sedentary animals live on different depths, including in the coastal tidal zone. Chitons are easily recognizable by their shell, which consists of eight plates. For example, tonicella. By the nature of their food, chitons are grazing animals: they crawl slowly, scraping algae from stones with powerful teeth of the radula.

Class Monoplacophora

This amazing group, which can be fully called living fossils. Fossilized remains of monoplacophorans were found by paleontologists as early as the 19th century. And in 1952, off the western coast of Mexico, in the ocean, at a depth of 3590 m, the first living representative of this class, neopilin, was discovered.

gastropods

Slugs
There are also unpleasant creatures among mollusks - slugs, pests of gardens and orchards. If you look at a slug, you will not see its usual shell. And it's not that the slugs don't have it, it's just that it has been reduced (reduced) into a small plate that is covered by the mantle.
Several species of slugs live in our country, they all look alike, and only one stands out among them - a large garden slug. It is colorfully colored (black spots are scattered over a gray background) and reaches an impressive length - 15 cm.
Without exception, slugs are malicious pests of cultivated plants. During the day they sit in some inconspicuous damp place, and with the onset of twilight they go to profit in the garden, where they eat not only tender greens, but also the upper part of root crops. They especially love delicious berries - strawberries and wild strawberries.
But the slugs themselves are not attractive to anyone as food. Only toads and hedgehogs are not averse to eating them, and the rest of the animals are scared away by the unpleasant mucus that covers their body.

Nudibranch mollusks are amazing representatives of the class of gastropods. Firstly, they do not have a shell at all, which is characteristic of all mollusks. Secondly, they lack a mantle cavity. Thirdly, their gills are different from those of snails: they are outgrowths of the body and can be located around the anus or in rows throughout the body. The lobes of the liver enter these outgrowths of the body. Fourthly, some nudibranch molluscs feed on coelenterates, for example poisonous polyps. Nudibranchs are not afraid of the stinging cells of polyps - the trick is that they eat them, but do not digest them. These cells accumulate in the very lobes of the liver and serve as weapons and protection for nudibranch mollusks.

cephalopods

Cephalopods are the owners of the largest brain among molluscs, they have a fast reaction and a good memory. Cephalopods include octopuses, squids and cuttlefish. Unlike other molluscs, cephalopods have tentacles with suction cups that serve as their arms. cephalopods surpassed everyone in their originality! They are not only the largest of the mollusks, but also the most complex. You certainly imagine the appearance of squids and octopuses well. These mollusks do not have a shell, their soft body “absorbed” it, and only a thin cartilaginous plate, the gladius, remained from the shell.
In the structure of these mollusks, the head and tentacles stand out, they are also legs - it is not without reason that they were called cephalopods. With the help of such legs, cephalopods can perform quite subtle manipulations (so it turns out that these are “legs”). Squids have ten, octopuses have eight tentacles covered with two rows of suction cups. But the first thing you pay attention to is not even numerous tentacles, but expressive eyes cephalopod. The eyes of octopuses, for example, are very similar to human ones: they not only see well, but are even capable of accommodation (focusing at different distances).
The octopus also has eyelids, only they close in a completely different way than in humans: circular muscle covers the eyeball from all sides.
In addition to vision, octopuses have a well-developed sense of touch and smell. In their travels along the seabed, octopuses rely mainly on their sense of smell - the eyes in muddy water can fail. But these animals do not hear very well: it is believed that they react only to very loud sounds.
Octopuses are excellent hunters: in addition to eight strong tentacles, they have one more weapon - horny jaws resembling the beak of a bird of prey. The bite of an octopus is poisonous, its poison is neurotoxic, that is, it affects the nervous system of the victims (fish, crabs, shrimp), causing paralysis. It is also dangerous for humans.
Another one interesting feature cephalopods - jet engine". Near the neck they have a wide funnel - a siphon coming out of the mantle cavity. Having collected water in the cavity, the mollusk with force throws it out of the siphon, moving forward. Octopuses thus move in fairly fast jerks, and squids, with their streamlined body, rush like rockets. There is only one inconvenience: the siphon is directed towards the tentacles, and therefore the cephalopods have to swim backwards. From here, by the way, came the opinion that cuttlefish (they are also cephalopods) always “retreat”. In fact, in a calm state, cuttlefish swim head first, like all other animals.
Squids most of the time slowly swim head first, helping themselves with their fins. When hunting, when high speed is needed, they use jet propulsion. This method of movement requires high energy costs, so animals cannot use it all the time.
The ancestors of cephalopods - octopuses, squids and their relatives - are ancient, long-extinct mollusks, ammonites and belemnites.
Ammonites looked like coil snails - they had the same shell, twisted in a flat spiral. But the sizes of these shells, and hence the mollusks themselves, were very different - from very small, a couple of centimeters in diameter, to incredibly huge three meters. Ammonites reigned serenely in the ancient seas 400 million years ago.
A little later, belemnites appeared, which looked more like modern squids. To this day, people find small pointed fossilized shells of these mollusks, which are called " damn fingers". The belemnite shell, like the ammonite, was divided into chambers and served as a kind of float.
But no less ancient cephalopods, nautiluses, have survived to this day. They have hardly changed over millions of years, their current appearance is almost the same as it was in ancient times.
Nautilus can sink to such depths where a strong steel tube would be flattened, unable to withstand the enormous pressure of the water, and he can! Its secret is not at all in the strength of the shell, but in the air pressure in its chambers, which “balances” the external water pressure.
From the swirling shell of a nautilus, almost a hundred arms-tentacles look out (the males, however, have fewer of them), devoid of suckers.
Argonauts are the closest relatives of nautiluses. Their shell is very thin, slightly curled. Argonauts are notable for the fact that their males are 20 times smaller than females! In addition, they reproduce in an amazing way. When the time comes to acquire offspring, one tentacle of the male breaks off and, taking with it the reproductive products (i.e., male germ cells), goes in search of a female. That's who the expression "offer a hand" takes on a literal meaning! The male argonaut is not in a hurry for a long journey - the “intelligent” limb will do everything by itself.
Relatives of the octopus - squids are no less amazing creatures. Outwardly, they are somewhat different from their counterparts: their body is narrower, the tentacles are not eight, but ten, and an additional pair (these two tentacles are called “arms”) are longer than the others. "Hands" end in a kind of extension with suction cups and hooks and are used for hunting. When the squid moves quickly, all its tentacles fold into one bundle - with them, like a steering wheel, the mollusk changes the direction of movement. If there is no need to rush anywhere, then it swims with the help of fins, it can also help with a jet of water thrown out from under the mantle.
Squids are able to develop such speed that they jump out of the water, rush through the air and dive back into the water. A similar method of movement is used, for example, by the squid stenoteuthis, escaping from a school of voracious tuna.
Interesting squid eyes. In some species, they are of different sizes - one is larger than the other. small eye helps to navigate near the surface of the water, where it is light, and the large one is able to capture the faintest light in the dark depths of the waters.
The body of deep-sea squids is very often decorated with a pattern of luminous dots or spots. They are called photophores. Each photophore has a hemispherical shape. Its bottom is covered with a shiny fabric, which plays the role of a mirror reflector. In front of it is a mass of phosphorescent cells. And on top - a transparent lens, which can be closed by a diaphragm (an opaque layer of black cells). The diaphragm, when necessary, "extinguishes" the luminous spot.
Some squids even have muscles that allow them to turn the photophore in different directions, changing the direction of illumination. It turns out that the photophore acts like a car headlight - nature long before man invented such a light source. Often, photophores are located next to the eyes, and even in front of the eyes themselves. Apparently, this helps to consider various items In the dark.
Unlike octopuses, which love to change color, squids are more permanent creatures. They do not live on the motley bottom, but in the transparent water column. So squids are able to change color from golden to red-brown, but usually remain colorless. And only an emotional shock can make a squid radically “repaint”.
But the cuttlefish dressed in a striped outfit. Of course, this coloring does not always merge with the colors of the underwater landscape, but it helps to disguise itself in a different way. The stripes, as it were, dismember the body of the mollusk into several parts, thereby hiding its true outlines. In the animal kingdom, a similar principle of “separating coloration” is very widely used. Some cuttlefish are even better at “changing their appearance” than octopuses, instantly drawing stripes or spots on themselves, depending on what is needed for camouflage.
Cuttlefish are able to illuminate the space around them. In the recess of the ink sac they have a "bubble" of bacteria that glows very brightly. The bottom of the recess is lined with a layer of shiny cells that play the role of a reflector. And in order to extinguish its flashlight, the cuttlefish secretes a few drops of ink into the mantle cavity: they cover the bag with bacteria with a thin film, “turning off” the light.
The marriage ceremony of cuttlefish is interesting. The male swims next to the female, following her everywhere. From time to time, the couple stops, the male swims forward, and the tentacles of the “lovers” intertwine, as if in an embrace. Such courtship can last more than one hour, but their result is always the same - the female lays eggs, hanging them on thin stems in a secret grotto. Performing this difficult work, she uses her side "hands". The cuttlefish ties the stalk extending from the egg around the support, and intertwines the stalk of the second egg with the stalk of the first - as a result, a bunch of eggs is formed, similar to a bunch of grapes (in Italy it is called “sea grapes”). Some species of cuttlefish that lay their eggs on the bottom mask the clutch with ink.
Many mysteries of cephalopods have not yet been solved. The problem, in particular, is that it is not easy to keep cephalopods in captivity - they are very sensitive to the quality of water and the amount of oxygen dissolved in it.

Interaction with humans Image of molluscs in · culture

For thousands of years, shellfish have been eaten by humans. In addition, shellfish served as a source of various valuable materials such as pearls, mother-of-pearl, purple, tkhelet and fine linen. In some cultures, clam shells served as currency. The bizarre shapes and gigantic size of some mollusks have given rise to myths about sea ​​monsters such as the kraken. Mollusks of some species are poisonous and can be dangerous to humans. There are also agricultural pests among mollusks, for example, giant Achatina.

Usage

Wool dyed with tkhelet pigment (pigment source - mollusk Murex trunculus)

In the food industry

Mollusks, especially bivalves, such as mussels and oysters, have served as human food since ancient times. Other shellfish commonly eaten include octopus, squid, cuttlefish and snails. In 2010, 14.2 million tons of shellfish were grown in aquaculture farms, which is 23.6% of the total mass of shellfish used for food. Some countries regulate the import of shellfish and other seafood, mainly to minimize the risk of poisoning by the toxins that accumulate in these organisms.

In terms of the volume of fishing, gastropod mollusks are inferior to bivalves. They eat such marine gastropods as the sea saucer ( Patella), abalone ( haliotis), trumpeters ( Buccinum) (fishing is carried out in Russia in the Far East, canned food is made from them), littorins ( Littorina), sea hares ( Aplysia). From land snails some countries eat snail genera Achatina, helix, slugs. In some European countries grape snails ( Helix pomatia) are bred in special farms.

Today, the production of bivalves is inferior to them artificial breeding in mariculture. Thus, mussels and oysters are grown on special farms. Such farms have achieved especially great success in the USA, Japan, France, Spain, and Italy. In Russia, such farms are located on the shores of the Black, White, Barents and Japan Seas. In addition, mariculture of sea pearl mussel is developed in Japan ( Pinctada). Strombus giant is a valuable commercial mollusk for the local population of the Caribbean, including Cuba.

Cephalopods are game animals; meat of cuttlefish, squid and octopus is used for food. Cuttlefish and some octopuses are harvested for the ink liquid used to make natural ink and ink.

In the production of luxury goods and jewelry

There is another article: pearls and purple

Most mollusks that have shells form pearls, but only pearls coated with a layer of mother-of-pearl have commercial value. They are created only by bivalves and some gastropods. Among natural pearls, bivalve pearls are the most valuable. Pinctada margaritifera and Pinctada mertensi living in the tropical and subtropical parts of the Pacific Ocean. Commercial pearl farming involves the controlled incorporation of solid particles into oysters and the subsequent collection of pearls. The ground shells of other mollusks often serve as the material for the introduced particles. The use of this material on an industrial scale has delivered some freshwater species bivalves in the southeastern United States are on the brink of extinction. The commercial cultivation of pearls has given rise to intensive research into mollusk diseases, which is necessary to ensure the health of the cultured species.

Byzantine emperor Justinian I dressed in purple and pearls

Mother-of-pearl mined from shells is used to make various items, such as buttons, and in addition to inlays.

In addition to pearls, shellfish are the source of some other luxury items. So, purple is extracted from the hypobranchial glands of some needles. According to the historian of the 4th century BC Theopompus, purple was worth its weight in silver. The many needlefish shells found in Crete support the assumption that the Minoan civilization was a pioneer in the use of purple as early as the 20th and 18th centuries BC, long before Tyre, with which the material is often associated. tkhelet (Hebrew) - a dye of animal origin, used in antiquity to dye fabric blue, cyan or purple-blue. Tkhelet is important to some Judaic rites as an obligatory attribute of items such as tzitzit (vision brushes) and the clothes of the high priest. Despite the fact that the method of obtaining tkhelet was lost in the 6th century AD, e., by now, a consensus has practically formed in the scientific world, according to which the source of tkhelet was also a representative of the family of needlefish - chopped off murex ( Hexaplex trunculus). fine linen - an expensive fabric, the material for the manufacture of which is byssus. It is a protein material secreted by some types of bivalve molluscs (most famously pinna nobilis) for attachment to the seabed. Procopius of Caesarea, describing the Persian wars of the middle of the VI century AD. e., argued that only members of the ruling classes were allowed to wear fine linen chlamys.

Mollusk shells (or their individual fragments) were used in some cultures as currency. The value of the shells was not fixed, but depended on the number of shells on the market. Therefore, they were subject to unforeseen surges in inflation associated with the discovery of a "gold mine" or improved methods of transportation. In some cultures, shell jewelry served as signs of social status.

as pets

At home, they often contain land giant Achatina and grape snails. In the aquarium hobby, snails, melania, coils and pond snails are common. In large aquariums, you can find octopuses, squids and cuttlefish.

In the research field

Cone toxins are highly specific in their effect. The relatively small size of their molecules facilitates their laboratory synthesis. These two qualities make cone toxins an object of research in the field of neuroscience. Shellfish are also of great interest for drug development. Mollusks pay special attention to themselves, in the digestive tract of which symbiotic bacteria live. Perhaps the substances secreted by these bacteria will find their use as antibiotics or neurological agents.

Other uses

The mineralized shell of mollusks is well preserved in fossil form. Therefore, in paleontology, fossil mollusks serve as "geological clocks" that allow stratigraphic dating of rock layers with great accuracy. Mollusk shells have been used since ancient times as a material for the manufacture of various tools: fish hooks, chisels, scrapers, hoe attachments. The shells themselves were used as vessels, and in addition musical instruments(conch) and ornaments.

The shells of predominantly gastropods, as well as bivalve and cephalopod mollusks, are the objects of a type of collection that is widespread in the world. It originated in the days of Antiquity, and reached its greatest popularity in the era of the Great Geographical Discoveries. In the middle of the 19th century, in the interior of Victorian houses, there is always a glass cabinet, where, along with fossils and minerals, shells were displayed. sea ​​shellfish. This type of collecting remains popular today.

Pests

200px( reticulated slug Deroceras reticulatum)

Some types of mollusks (mainly snails) are pests of agricultural crops. Such a species, getting into a new habitat, is able to unbalance the local ecosystem. An example is the giant Achatina ( Achatina fulica) is a plant pest. It has been introduced to many areas of Asia, as well as to many islands in the Indian and Pacific Oceans. In the 1990s, this species reached the West Indies. An attempt to fight it by introducing a predatory snail Euglandina rosea only worsened the situation: this predator ignores Achatina and instead exterminates local species of snails.

Grape snail harms grapes, and slugs harm garden crops. Field Slug ( Agriolimax agrestis) harms winter crops, potatoes, tobacco, clover, garden plants, and net slug ( Deroceras reticulatum) causes damage to tomato and cabbage crops. In the southern regions, slugs of the genus Parmacella.

New Zealand freshwater snail Potamopyrgus antipodarum was first recorded in North America in the mid-1980s - first in the western, and then in the eastern states of the United States. Despite the fact that the length of one snail is on average about 5 mm, its exceptional fecundity leads to a concentration of up to half a million individuals per square meter, which leads to the rapid extinction of local insects and mollusks, as well as fish associated with them in the food chain.

Some mollusks are enemies of commercial mollusks, for example, the aforementioned predatory snails. Crepidula fornicata in some cases appear on oyster banks (i.e. shoals North Sea and the Atlantic Ocean) and in such quantities that the oysters themselves become invisible; as a result, the oysters die.

Shipworms from the class of bivalves settle in wood submerged in water, including in the underwater parts of wooden boats and ships, as well as in stationary hydraulic structures. In the course of its life activity (see the nutrition section above), the shipworm grinds numerous passages in the wood, which contributes to its rapid destruction. The annual damage caused by shipworms is in the millions.

Small bivalve Dreissena polymorpha is attached to a solid substrate by the byssus and forms significant accumulations. Often, she settles in pipes and conduits, clogging them.

Shellfish and human health

Many mollusks produce or accumulate from environment toxins that pose a threat to health, and in some cases, human life. Poisoning can occur when a mollusc is bitten, touched, or eaten. To reduce this threat, many countries restrict shellfish imports. Among the deadly mollusks, one can note some types of cones from the class of gastropods and the blue-ringed octopus (which, however, attacks a person only if provoked). All octopuses are venomous to some degree.

However, it should be noted that the number of people who die from contact with mollusks is less than 10% of people who die from contact with jellyfish. Bite tropical species octopuses Octopus apollyon causes severe inflammation that can last for more than a month even with proper treatment. Bite Octopus rubescens with the wrong treatment, it can cause tissue necrosis, and with the right one, it can be limited to a week of headaches and general weakness.

Living cones like this textile cone are dangerous for pearl divers but are of interest to neuroscientists.

Cones of all kinds are poisonous and can sting when touched. But representatives of most species are too small to be a serious threat to humans. Usually these predatory gastropods feed on marine invertebrates (some large species also feed on fish). Their venom is a mixture of many toxins, some of which are fast acting, while others are slower but more potent. Based on the chemical composition of cone toxins, they require less energy to produce than snake or spider toxins. There are documented evidence of numerous cases of poisoning, as well as a number of deaths. Apparently, only a few large species pose a serious danger to humans: those that are able to catch and kill fish.

There are also bivalves that are poisonous to humans; poisoning may be accompanied by a paralytic effect (eng. Paralytic shellfish poisoning, PSP ), memory loss Amnesic shellfish poisoning, ASP ), gastroenteritis, long-term neurological disorders, and even death. The toxicity of bivalves is due to their accumulation of toxin-producing unicellular organisms: diatoms or dinoflagellates, which they filter out of the water; sometimes toxins persist even in well-cooked clams. Yes, bivalve venom Crassostrea echinata due to protist toxins Pyrodinium bahamense from the group of dinoflagellates.

Giant tridacna ( Tridacna gigas) can theoretically pose a danger to a person, firstly, because of the sharp edges, and secondly, it can clamp the diver’s limb with the wings. At the same time, no human deaths due to tridacna have been reported so far.

Mussels (and also mytilids) are the so-called marine bivalve mollusks that live throughout the world's oceans and have been eaten by humans since time immemorial.

The most popular for cooking edible mussels Black Sea mussels are considered and, caught in the cold Seas of Japan and Okhotsk, as well as in the northwestern part of the Pacific Ocean, Gray mussels (or giant mussels).

Annually, during the season of active fishing/gathering of these delicious shellfish(at the very end of August) in the small Belgian village of Yersek, “Mosseldag” (Mussel Day) is held - a holiday during which people eat shell clams in truly huge quantities in local restaurants and cafes. By the way, the only Mussel Exchange in the world is located here, so there is no end to buyers (retail and wholesale), as well as tourists, as they say.

Now mussels are not only caught in their natural habitat, but also artificially grown on special platform farms. And the cost of the meat of such mussels in the refrigerated display cases of supermarkets is somewhat cheaper than the meat of their "wild" counterparts.

Nutritional value and chemical composition of mussels

The nutritional value:

• Calories: 77 kcal
• Proteins: 11.5 gr
• Fats: 2 gr
• Carbohydrates: 3.3 gr

• Water: 82 gr
• Saturated fatty acids: 0.4 g
• Cholesterol: 40 mg
• Ash: 1.6 gr

Macronutrients:

• Calcium: 50 mg
• Magnesium: 30 mg
• Sodium: 290 mg
• Potassium: 310 mg
• Phosphorus: 210 mg
• Sulfur: 115 mg

Vitamins:

• Vitamin PP: 1.6 mg
• Vitamin A: 0.06 mg
• Vitamin A (RE): 60 mcg
• Vitamin B1 (thiamine): 0.1 mg
• Vitamin B2 (riboflavin): 0.14 mg
• Vitamin C: 1 mg
• Vitamin E (TE): 0.9 mg
• Vitamin PP (Niacin equivalent): 3.7 mg

Trace elements:

• Iron: 3.2 mg

Mussels are one of the lowest calorie foods that modern man eats. They are rich in healthy proteins (by the way, there are much more proteins in mussels than in any fish or even meat) and contain almost no carbohydrates.

What are useful mussels

The benefits of mussels are determined by the composition of their meat (muscle), as well as the mantle and shell fluid, which are also used to prepare delicious dishes.

Inclusion of mussels in the diet modern man(with regular use) provides:

• improved metabolism;
• increase in immune status.

Mussel meat is a product that can provide a fairly reliable prevention of arthritis. And besides, such meat stimulates:

• circulation;
• removal of toxins and toxins from the body.

Mussel meat is literally saturated with mineral salts, vitamins (here, almost the entire group B, as well as vitamins PP, E and D), microelements. Mussels contain a lot of phosphorus, iron, manganese, zinc and cobalt. The content of iodine is high, as well as useful fatty polyunsaturated acids.

Like any of the seafood, mussels have a beneficial effect on activity. . They also improve mood and provide prevention of numerous nervous disorders. Regular consumption of mussels in food is a guarantee of bone strength, prolongation of external youth, maintenance of the natural beauty of skin and hair.

The positive effect of meat, mantle and shell fluid of mussels on male potency has been proven. Some doctors even call this product "natural Viagra".

But for children, pregnant and lactating women, mussels are little recommended because of some features of their existence that can affect the quality of nutrition of these population groups. So that beneficial features Mussels are far from being appreciated by everyone.

Why are mussels harmful?

Mussels can be harmful to human health. Especially if they do not undergo mandatory pre-sale preparation (we are talking about mollusks living in their natural habitat). They can interfere with blood clotting and can cause serious allergic reactions.

In addition, the harm of mussels has been proven for patients suffering from gout, since in the human body protein compounds are converted into uric acid, and it can be painfully deposited in the joints.

But in general, mussels have few contraindications. In fact, anyone can eat these mollusks in reasonable quantities. Unless, of course, there is no individual intolerance to seafood.

Features of the preparation and use of mussels

Freshly caught mussels, unless they have been grown artificially on special plantation farms, should not be eaten. They must be kept (and not less than a month) in fresh ponds-settlers.

The fact is that these shellfish are living natural filters, the mission of which is to purify the natural environment of their own habitat. They are able to accumulate toxins and microorganisms that are harmful to human health. And they just need a fairly long quarantine to get rid of the sometimes frankly dangerous "luggage".

When buying mussels in a supermarket, it is better to choose frozen packages. Unless you live near the above mentioned shellfish farm. And you should pay attention to the appearance of the purchase - if the mussels stick together into an ice lump, there is a great danger that they have already been defrosted. And maybe even spoiled.

Calories, kcal:

Proteins, g:

Carbohydrates, g:

Mollusks, they are also soft-bodied, are animals distinguished by spiral crushing. In general, today there are already more than two hundred thousand different types soft-bodied. Mollusks, as an animal species, have adapted to life in absolutely the entire habitat of the Earth (calorizator). They can be found both in the seas and in the rivers. Also a large number of species lives on land.

A huge number of species of mollusks are different in size. The smallest adult mollusks are only 0.5 mm in size. The largest of the known reached 16 meters, really gigantic specimens.

Some species of mollusks are on the verge of extinction, due to exorbitant industrial production, as well as human activity leading to a change in the habitual environment.

It is known that the way of life, the appearance of an animal depends on the type of mollusk and its habitat. There are several main types into which mollusks are divided:

• shellfish chitons or deep-sea underwater animals whose diet is various algae, as well as other inhabitants of the ocean. Habitat - Pacific Ocean;
• gastropods are the most common types of soft-bodied, in turn are divided into keel-legged and wing-legged;
• bivalves, this species includes food, as well as dates, folad and byssus, the most inactive types of mollusks;
• cephalopods, this species includes well-known animals, plankton, and others. Cephalopods are most often predators.

Calorie content of shellfish

The calorie content of shellfish is on average only 77 kcal per 100 grams of product.

The composition and beneficial properties of shellfish

Directly the chemical composition of the mollusk depends on a number of factors, first of all, it is the type of animal, lifestyle, and habitat (calorizer). Shellfish contain a large number of useful compounds necessary for humans.

Shellfish in cooking

Many types of mollusks are suitable for eating, but not only in the food industry they have found a place. Mollusks are also often used in medicine and cosmetology.

molluscum contagiosum- this is viral disease that affects the skin. The disease itself does not cause concern, but it can spoil the appearance of a person and cause him suffering of a psychological nature. The disease got its name due to the specific form of the virus, which, when viewed under a microscope, resembles a clam shell. This pathology has a high degree contagiousness. As a rule, you can become infected with molluscum contagiosum through direct contact with a sick person. The disease develops in both children and adults, but the symptoms of the disease are expressed in different ways. Molluscum contagiosum occurs only in humans, animals do not get sick with it.

Causes of molluscum contagiosum

The causative agent of the disease is the molluscum contagiosum virus, which belongs to the smallpox group. The virus that causes this disease is often identified with acrochordon (a disease that provokes the papilloma virus), since according to outward signs they have similar manifestations.

Clinical picture

The disease has an incubation period, which ranges from 2 weeks to six months from the moment of infection. Small nodules appear on the patient's skin, which disappear on their own, but new ones appear in their place. This process has long period, which is calculated in months, years and decades. If signs of inflammation caused by other infectious pathologies appear on the affected areas, then the disease takes on a complicated form.

The causative agent of the disease, and specifically the virus, affects only the surface layer of the skin, it does not penetrate into the blood, internal organs does not affect. This pathology is characterized by the formation on the skin of small painless nodules of a dense consistency, bodily, light pink or white color. Rashes are localized singly or systemically in groups on any part of the body. There have been cases of merging of nodules with each other into one large mollusk. Sometimes, when pressed, a white slurry is released from the nodule, which contains both keratinized cells and mollusc-like bodies of viruses. In adults, as a rule, rashes are localized in the genital area, and in children, the face, hands, stomach and chest are more often affected. Very often, the disease develops in people with immunodeficiency conditions, so other skin infections, such as atopic dermatitis, can join this pathology. In this case, we can talk about a complicated form of the disease. With complications, the symptoms of the disease are more pronounced, more severe and resistant to therapy.

How can you get infected?

Infection occurs as a result of contact with the contents of the nodules on healthy skin. In most cases, children become infected while playing with sick children, and adults most often through sexual contact, when there is closer contact with the skin. But not all adults get sick with molluscum contagiosum, as many have immunity to the molluscum virus. This pathology usually develops in adults with immunodeficiency states. You can also become infected with a mollusk through indirect contact through common household items, personal items, clothes, towels, bed linen, in public places: swimming pools, saunas, sports centers.

Diagnosis of the disease

The disease does not seem to be dangerous, it is easily diagnosed due to specific manifestations and symptoms, but in some cases, differential diagnosis is needed with other more dangerous diseases, such as: syphilis and human papillomavirus (HPV). In addition, infection with molluscum contagiosum may be a sign of other serious illnesses such as AIDS.

Molluscum contagiosum treatment

Molluscum contagiosum definitely needs treatment because the virus is highly contagious and has the ability to spread to healthy tissue. In most cases, infected people do not go to the doctor, since there are no subjective sensations with this disease. The rashes do not hurt and do not peel off, only occasionally there is a slight itch. And only in the case of a secondary infection, severe inflammation of the skin occurs. In this case, the disease is much more serious and longer, and the infection demonstrates high resistance to therapy. As a result, the advanced form of the disease manifests itself as a generalized infection, when the nodules begin to spread throughout the body.

Damage to the integrity of the molluscum contagiosum is especially dangerous, in this case there is a large-scale spread of the mollusk on the skin. The damaged mollusk must be removed in a medical institution, and the wound should be cauterized with aseptic means.

Currently, the tactics of treating the disease is to remove the mollusk using antiviral and immunostimulating agents. You can not self-medicate and remove the nodules on your own, trying to "squeeze" them out. This can cause severe inflammation of the skin and the spread of the disease to healthy tissues. Molluscum contagiosum is removed only by a dermatologist in medical institution. This is jewelry and painstaking work. Each nodule is removed with tweezers or a Volkmann spoon. The wounds formed after removal are lubricated with an alcohol solution of iodine or a solution of potassium permanganate.

AT recent times The laser method of removing molluscum contagiosum is very popular, especially with generalized skin lesions. The laser delicately eliminates nodules without affecting neighboring healthy tissues and without leaving scars on the skin.

In addition to laser therapy, other methods of removing molluscum contagiosum are used: cryotherapy and diathermocoagulation.

The essence of cryotherapy is to cauterize the elements of the virus with liquid nitrogen. The method of diathermocoagulation consists in the coagulation of tissues in order to destroy the virus and remove it. This method is carried out using an alternating electric current of high frequency.

Over the next few days after the removal of the mollusk, the wounds are smeared with an alcoholic solution of iodine once a day. Wilkinson's ointment heals wounds especially well. Not always, after a radical removal, the mollusk virus immediately disappears. For some time, the appearance of new nodules may still be observed. This is due to the fact that the mollusk is not destroyed immediately, this process is gradual. New nodules should be removed until they are completely gone. And this will certainly happen. The disease has a high likelihood of recurrence. For this reason, treatment should not be interrupted, and the remaining wounds should be treated steadily with antiviral ointments (viferon, liniment, cycloferon, acyclovir), which improve skin immunity.

After removing the mollusk, it is necessary to take a number of preventive measures to avoid recurrence:

• treat personal items with disinfectant solutions;
• boil bed and underwear;
• do not use common household items;
• provide the patient with individual items for personal use;
• be sure to undergo an examination for the detection of molluscum contagiosum in other family members, especially those with whom the patient is in an intimate relationship.

Thus, the treatment of molluscum contagiosum is carried out in four directions:

1. Mechanical scraping of a mollusk with a sharp Volkmann spoon.
2. Surgical treatment (this also includes laser therapy and diathermocoagulation).
3. Local treatment with antiviral ointments.
4. Treatment with immunomodulators.
5. In the case of generalized tissue damage, tetracycline antibiotics (oletethrin, tetracycline, metacycline) are prescribed.

Prognosis and prevention of the disease

The prognosis of the disease is favorable. The main measure of prevention is the observance of the rules of personal hygiene. To prevent the spread of the disease, the following measures are taken:

• in kindergartens and schools, it is necessary to isolate a child suffering from molluscum contagiosum;
• a preventive examination of healthy children is necessary in order to identify potential carriers of the infection;
• adults and children need to change underwear daily;
• each person uses only their personal items for individual use (combs, sponges, toothbrushes, towels, etc.)
• carry out daily water procedures and observe the rules of personal hygiene.

The main measure for the prevention of sexually transmitted diseases is legibility in choosing a sexual partner.