Infusoria-shoe - a type of protozoan unicellular animals from the class of ciliary ciliates such as ciliates. This species got its name for its resemblance to the sole of a shoe.
Ciliates-shoes live in fresh water bodies of any type with stagnant water and the presence of a mass of decaying organic substances in the water. Also, these organisms are found in aquariums. This can be verified by taking samples of water with silt from the aquarium and examining them under a microscope.
In the structure of ciliates-shoes are noted characteristics. This is a relatively large organism, body size reaches 0.5 mm. The minimum size of individuals is from 0.1 mm. The shape of the body, as already noted, resembles a shoe. The outer shell of this simplest is the outer membrane. Under it is the pellicle - a dense layer of cytoplasm with flattened membrane cisterns (alveoli), microtubules and other components of the cytoskeleton.
The entire surface of the ciliate-shoe cell is covered with cilia, the number of which ranges from 10 to 15 thousand. At the base of each cilium is the so-called basal body. All basal bodies make up a complex cytoskeleton system of the ciliates-shoes. Between the cilia there are organelles that perform a protective function - spindle-shaped bodies (trichocysts). In their structure, a body and a tip are distinguished, enclosed in a membrane sac. The response of the trichocyst to irritation (heating, contact with a predator) is its instantaneous elongation (6-8 times) when the outer membrane fuses with the membranous sac of the trichocyst, which looks like a “shot”. In the aquatic environment, trichocysts impede the movement of a predator approaching the ciliates. One individual of this species can have from 5 to 8 thousand trichocysts.
The movement of ciliates-shoes is possible due to the wave-like movements of the cilia. So it floats with a blunt edge forward at a speed of about 2 mm / s. Basically, the infusoria-shoe moves in one plane, while in the thickness of one mass an individual can rotate around the longitudinal axis. The simplest change direction of movement, due to the bends of their body. If the infusoria collides with an obstacle, it immediately begins to move in the opposite direction.
What does the infusoria-shoe eat? The nutrition of this simplest has characteristic features. The basis of the diet of ciliates-shoes are bacteria, the accumulations of which attract ciliates by releasing special chemical substances. Also, ciliates can swallow other particles suspended in water, even without special nutritional value. In the organism of the simplest, a cellular mouth is distinguished, passing into a cellular pharynx. Near the mouth are special cilia, collected in complex complexes. With the wave-like movements of the cilia of this type, food with a stream of water enters the pharynx. A large digestive vacuole forms at the base of the pharynx. This vacuole, like all subsequent newly formed ones, migrates in the cytoplasm of the organism of an individual along a certain “path” - from front to back, and then from back to front (as if in a circle), while the large vacuole breaks up into smaller ones. Thus, the absorption of nutrients is accelerated. Digested substances enter the cytoplasm, where they are used for the needs of the body. Waste substances are excreted into environment through the powder in the back of the cell - an area with an underdeveloped pellicle.
In the ciliate-shoe cell, there are two contractile vacuoles in front and behind the body. In the structure of such a vacuole, a reservoir and tubules are distinguished. Through the tubules, water enters the reservoir from the cytoplasm, from which it is pushed out through the pore. Thanks to the cytoskeleton of microtubules, the entire complex is constantly located in a certain area of the cell. Main function contractile vacuoles - osmoregulatory. Through them, excess water is removed from the cell, as well as products of nitrogen metabolism.
Infusoria-shoes breathe through the entire surface of the body. And with a reduced concentration of oxygen in the water, the ciliates live due to glycolysis.
Two cores of infusoria-shoes have a different structure and perform various functions. The small nucleus is diploid, has a rounded shape; the large nucleus is polyploid, bean-shaped. The small nucleus is responsible for sexual reproduction, and the large nucleus directs the synthesis of all proteins in the ciliate-shoe cell.
Asexual reproduction occurs by cell division in half. Sexual reproduction occurs through conjugation. Two shoes are connected and, with complex transformations of the nuclei, new individuals are formed.
Infusoria shoe belongs to the type of ciliates (Infusoria), which has over 7 thousand species. Compared with other groups of protozoa, ciliates have the most complex structure, being the pinnacle of the organization of unicellular animals. The infusoria-shoe lives in almost all freshwater reservoirs and is an integral part of the "dust". They can be easily detected under a microscope among silt particles and the remains of rotting plants taken from an aquarium.
Among the simplest ciliates, shoes are rather large organisms, the sizes of which usually range from 0.1 to 0.3 mm. The ciliate shoe got its name due to the shape of its body, reminiscent of a lady's shoe.
It maintains a constant body shape due to the fact that the outer layer of its cytoplasm is dense. The entire body of the ciliate is covered with longitudinal rows of numerous small cilia that perform undulating movements. With their help, the shoe floats with the blunt end forward. A groove with longer cilia runs from the anterior end to the middle of the body. At the end of the groove there is a mouth opening leading to the pharynx. Infusoria feed mainly on bacteria, driving them to the mouth with cilia. The mouth opening is always open. Small food particles penetrate through the mouth into the pharynx and accumulate at its bottom, after which the food lump, together with a small amount of liquid, comes off the pharynx, forming a digestive vacuole in the cytoplasm. The latter makes a complex path in the body of the ciliates, during which the digestion of food is carried out.
In addition to bacteria, ciliates feed on yeast and algae. When feeding them with algae, exposure to direct sunlight should be avoided, since the oxygen released by freshly swallowed algae can break the ciliates. It should be borne in mind that ciliates can filter and swallow any particles, regardless of their nutritional value. Therefore, the presence of foreign suspended particles in the vessel with ciliates should be avoided, since if the ciliates overflow their mouth opening with foreign suspension, the ciliates may die.
Infusoria slipper mobile enough. The speed of its movement at room temperature is 2.0 - 2.5 mm/sec. This is a high speed: in 1 second the shoe covers a distance exceeding the length of its body by 10-15 times. This circumstance must be taken into account when feeding small, inactive larvae of some spawning fish, which, even with a high concentration of ciliates, can remain hungry.
For breeding ciliates at home, it is better to use a pure culture, after making sure it is clean under a microscope. In the absence of a pure culture, you can get it yourself. To do this, a few drops of a suspension of silt with plant residues taken from the bottom of the aquarium are placed on the glass, to which a drop of milk or a grain of salt is added. Next to it from the side of the world, a drop of fresh, settled water is dripped. Both drops are connected by a water bridge using a sharpened match. The shoe rushes towards fresh water and light at a faster speed than all other microorganisms. Shoes reproduce very quickly: to reach their maximum concentration of 40 thousand ind./cm from a single individual, under optimal cultivation conditions, less than a month is needed.
For breeding shoes, all-glass vessels with a volume of 3 liters or more are usually used. Good results are achieved at room temperature, but the peak of reproduction of ciliates is observed at 22 - 26°C. In the first days of cultivation, a weak purge is desirable, but at the same time, sediment should not rise from the bottom of the jar. In the presence of a purge, the ciliates are located at the bottom of the jar, and with a lack of oxygen, they rush to the surface of the water. This property is usually used to concentrate ciliates before feeding them to their larvae.
As food for ciliates, you can use hay infusion, dried peels of banana, pumpkin, melon, yellow swede, sliced carrots, fish feed pellets, milk, dried lettuce, liver pieces, yeast, algae, i.e. those substances that are either directly consumed by shoes (yeast, algae), or are a substrate for the development of bacteria.
When using hay, take 10 g of it and place it in 1 liter of water, boil for 20 minutes, then filter and dilute with an equal amount or two-thirds of settled water. During boiling, all microorganisms die, but bacterial spores remain. After 2-3 days, hay sticks develop from spores, serving as food for ciliates. As needed, the infusion is added to the culture. The infusion is stored in a cool place for a month.
The shoe can be bred on dried lettuce leaves or liver pieces placed in a gauze bag.
The peel of ripe, intact bananas, melons, swedes, pumpkins is dried and stored in a dry place. Before entering the culture, take a piece 1-3 cm in size, rinse and pour 1 liter of water. Hydrolytic yeast is added at the rate of 1 g per 100 liters. Most in a simple way is the cultivation of shoes on skimmed, boiled or condensed (without sugar) milk: it is introduced into the culture 1 - 2 drops per 1 liter) once a week. Shoes use lactic acid bacteria.
When using the above feeds, it is important not to overdose on nutrition. Otherwise, rapidly multiplying bacteria will leave the ciliates without oxygen. When ciliates are grown on bacteria, they have positive phototaxis, i.e. yearn for the light. You can breed ciliates on stagedesmus and chlorella algae. Good results can be achieved when cultivating ciliates with weak blowing, when 1 granule of carp compound feed is added per 1 liter of algae. Ciliates fed with algae have negative phototaxis: they tend to darkness. This property can be used when feeding shade-loving fish larvae. Use the culture of ciliates, as a rule, no longer than 20 days. To maintain the culture at all times, it is charged in two cans at weekly intervals, with each can being recharged every two weeks. For long-term storage of ciliates culture, it is placed in a refrigerator and stored at a temperature of + 3°- + 10°C.
The collection of ciliates is carried out in places of their highest concentration using a rubber hose. Concentration of ciliates can be done by carefully introducing a saline solution into the culture, which, sinking to the bottom of the jar, causes the ciliates to concentrate at the surface. An easier way to collect ciliates is to introduce milk into the culture while turning off the purge. After 2 hours, the ciliates are concentrated at the surface on the illuminated side of the jar.
Particularly good results can be achieved if the culture is placed in a cylinder, adding milk and salt to it. In this case, cotton wool is placed on the surface of the liquid, and then fresh water is carefully added to the cotton wool, while the upper part of the cylinder is illuminated. After half an hour, most of the shoes are moved into fresh water, and this water with ciliates is transferred to a vessel with fish larvae. To feed many characins and a number of other fish, the larvae of which cannot stand the presence of bacteria, infusoria can withstand a day or two in clean water. During this time, the shoes eat all the bacteria and thus disinfect the water.
For a constant supply of ciliates to the aquarium with fish larvae, a jar of ciliates is placed above the aquarium and from it, through a hose with a clamp, water with ciliates drops into the aquarium with larvae. You can pour water with ciliates not with a hose, but with a moistened linen thread. Feeding by ciliates of the larvae of most fish is usually carried out only during the first two or three days with the gradual addition (on the second day) of larger food organisms.
Paramecium caudatum Ehrenberg, 1838
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Infusoria shoe, paramecia caudate(lat. Paramecium caudatum) - a species of ciliates of the genus Paramecium, is included in a group of organisms called protozoa, a unicellular organism. Usually other species of the genus Paramecium are also called ciliates-shoes. Water environment habitats found in fresh waters. The organism got its name from the permanent shape of the body, resembling the sole of a shoe.
According to another classification scheme, they are placed in the animal kingdom in the order of equal-sized ( Holotricha) subclass of ciliary ciliates ( Ciliata) of the class Ciliophora of the protozoan type ( Protozoa), and according to the third scheme - to the order Hymenostomatida of the subclass Holotrichia. There are also numerous other classification schemes for ciliates.
Infusoria slipper
The habitat of the shoe ciliates is any fresh body of water with stagnant water and the presence of decaying organic substances in the water. It can also be detected in an aquarium by taking samples of water with silt and examining them under a microscope.
Dimensions different types shoes are from 0.1 to 0.6 mm, caudate paramecium - usually about 0.2-0.3 mm. The shape of the body resembles the sole of a shoe. The outer dense layer of the cytoplasm (pellicle) includes flat membrane cisterns of the alveoli, microtubules and other elements of the cytoskeleton located under the outer membrane.
On the surface of the cell, cilia are located mainly in longitudinal rows, the number of which is from 10 to 15 thousand. At the base of each cilium there is a basal body, and next to it is the second one, from which the cilium does not depart. Infusoria is associated with basal bodies in ciliates - a complex system cytoskeleton. In the slipper, it includes postkinetodesmal fibrils extending backwards and radially diverging transversely striated filaments. Near the base of each cilium there is an invagination of the outer membrane - the parasomal sac.
Between the cilia are small spindle-shaped bodies - trichocysts, which are considered as protective organelles. They are located in membranous sacs and consist of a body and a tip. Trichocysts are a variety of organelles with a variety of structure extrus, the presence of which is characteristic of ciliates and some other groups of protists. Their body has a transverse striation with a period of 7 nm. In response to irritation (heating, collision with a predator), trichocysts shoot out - the membrane sac merges with the outer membrane, and the trichocyst lengthens 8 times in thousandths of a second. It is assumed that trichocysts, swelling in water, can impede the movement of a predator. Known mutants of shoes, devoid of trichocysts and quite viable. In total, the shoe has 5-8 thousand trichocysts. Shoe 2 has contractile vacuoles in the anterior and posterior parts of the cell. Each consists of a reservoir and radial channels extending from it. The reservoir opens outward at times, the channels are surrounded by a network of thin tubes through which fluid enters them from the cytoplasm. The entire system is held in place by a microtubule cytoskeleton.
The shoe has two nuclei different in structure and function - a rounded diploid micronucleus (small nucleus) and a bean-shaped polyploid macronucleus (large nucleus).
It consists of 6.8% dry matter, of which 58.1% is protein, 31.7% is fat, 3.4% is ash.
Kernel functions
The micronucleus contains a complete genome, almost no mRNAs are read from its genes and therefore its genes are not expressed. When the macronucleus matures, complex rearrangements of the genome occur, it is from the genes contained in this nucleus that almost all mRNA is read; therefore, it is the macronucleus that “controls” the synthesis of all proteins in the cell. A shoe with a removed or destroyed micronucleus can live and reproduce asexually, but loses the ability to reproduce sexually. During sexual reproduction, the macronucleus is destroyed, and then restored anew from the diploid primordium.
Movement
Making wave-like movements with cilia, the shoe moves (floats with a blunt end forward). The eyelash moves in one plane and makes a direct (effective) blow in a straightened state, and a return blow in a curved state. Each next eyelash in a row strikes with a slight delay compared to the previous one. Floating in the water column, the shoe rotates around the longitudinal axis. The movement speed is about 2 mm/s. The direction of movement can change due to the bending of the body. When hitting an obstacle, the direction of the direct impact is reversed and the shoe bounces back. Then it “swings” back and forth for a while, and then starts moving forward again. Upon collision with an obstacle, the cell membrane depolarizes, and calcium ions enter the cell. In the "rocking" phase, calcium is pumped out of the cell.
Nutrition and digestion
On the body of the ciliate there is a recess - a cellular mouth, which passes into the cellular pharynx. Near the mouth are specialized cilia of the perioral cilia, "glued" into complex structures. They drive into the throat along with the flow of water the main food of ciliates - bacteria. The ciliate finds its prey by sensing the presence of chemicals that are released by clusters of bacteria.
Feeding grouped ciliates with green algae
At the bottom of the pharynx, food enters the digestive vacuole. Digestive vacuoles move in the body of the ciliates by the flow of the cytoplasm along a certain "route" - first to the posterior end of the cell, then to the anterior and then again to the posterior. In the vacuole, food is digested, and the digested products enter the cytoplasm and are used for the life of the ciliate. First, the internal environment in the digestive vacuole becomes acidic due to the fusion of lysosomes with it, then it becomes more alkaline. In the course of migration of the vacuole, small membrane vesicles separate from it (probably, thereby increasing the rate of absorption of digested food). The undigested food remains inside the digestive vacuole are thrown out in the back of the body through a special area of the cell surface, devoid of a developed pellicle - cytopyg, or powder. After merging with the outer membrane, the digestive vacuole immediately separates from it, disintegrating into many small vesicles, which migrate along the surface of microtubules to the bottom of the cell pharynx, forming the next vacuole there.
Respiration, excretion, osmoregulation
The shoe breathes the entire surface of the cage. It is able to exist due to glycolysis at a low concentration of oxygen in water. Products of nitrogen metabolism are also excreted through the cell surface and partially through the contractile vacuole.
The main function of contractile vacuoles is osmoregulatory. They remove excess water from the cell, penetrating there due to osmosis. First, the leading channels swell, then the water from them is pumped into the tank. When the reservoir shrinks, it separates from the supply channels, and water is ejected through the pore. Two vacuoles work in antiphase, each under normal physiological conditions is reduced once every 10-15 s. In an hour, vacuoles eject from the cell a volume of water approximately equal to the volume of the cell.
reproduction
The shoe has asexual and sexual reproduction (sexual process). Asexual reproduction - transverse division in the active state. It is accompanied by complex regeneration processes. For example, one of the individuals re-forms a cell mouth with a perioral cilia, each completes the missing contractile vacuole, the basal bodies multiply and new cilia form, etc.
The sexual process, like that of other ciliates, occurs in the form of conjugation. Shoes belonging to different clones are temporarily “glued together” by their mouth sides, and a cytoplasmic bridge is formed between the cells. Then the macronuclei of the conjugating ciliates are destroyed, and the micronuclei are divided by meiosis. Of the four haploid nuclei formed, three die, and the remaining one divides by mitosis. Each ciliate now has two haploid pronuclei - one is female (stationary) and the other is male (migratory). Ciliates exchange male pronuclei, while females remain in their "own" cell. Then, in each ciliate, "own" female and "foreign" male pronuclei merge, forming a diploid nucleus - a synkaryon. When the synkaryon divides, two nuclei are formed. One of them becomes a diploid micronucleus, and the second turns into a polyploid macronucleus. In reality, this process is more complicated and is accompanied by special post-conjugation divisions.
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See what "Infusoria-shoe" is in other dictionaries:
Infusoria slipper- ? Infusoria shoe Infusoria shoe (Paramecium caudatum) Scientific classification Kingdom: Protists Type: Ciliates ... Wikipedia
infusoria-shoe- ciliate shoe, ciliate shoe ... Spelling Dictionary
infusoria- slipper, paramecium, stentor, opaline, polygastrica, chilodon, chonotrich, entodiniomorph, psammon, suvoyka Dictionary of Russian synonyms. ciliates n., number of synonyms: 24 acinetes (1) ... Synonym dictionary
Its body is elongated and outwardly resembles a boat shoe: the anterior end is narrower, the greatest width is in the posterior third. The posterior end is somewhat pointed and covered with long cilia. On the side of the body, conditionally called the abdominal, a deep groove protrudes inside - this is a perioral recess - a peristome, in the back of which there is a mouth opening leading to the pharynx. The cilia on the walls of the peristome are longer; this is a kind of trapping apparatus that drives the food of the ciliate into the mouth opening. Cilia create a continuous flow of water, with which small food particles - mainly bacteria - penetrate through the mouth into a short pharynx and accumulate at the bottom. Together with a small amount of liquid, food particles break away from the bottom of the pharynx and enter the cytoplasm, forming a digestive vacuole, which, separated from the pharynx, makes a regular path in the body of the ciliate, which takes about one hour. The digestive vacuole first moves towards the posterior end of the body and, having described a small arc, returns to the anterior end. From here it describes an already closed arc along the periphery of the body. At this time, digestive enzymes enter the vacuole, and the digested food is absorbed into the cytoplasm. The path of the digestive vacuole ends with a powder - a certain place where undigested residues are thrown out.
The slipper can be considered one of the most voracious animals: it feeds continuously, its mouth opening is always open and the flow of food particles into the mouth does not stop. This process stops only during periods of reproduction.
The entire body of the ciliate is covered with cilia, there are about 10-15 thousand of them. They constantly make coordinated paddle-like movements, due to which the animal moves all the time. The speed of movement is 2-2.5 mm / s, i.e. in a second, a shoe runs a distance exceeding the length of its body by 10-15 times. When moving forward, the animal also rotates along the longitudinal axis of the body.
Under the shell, in the outer layer of the cytoplasm near the shoe, there are numerous short formations resembling sticks - trichocysts. This is an amazing protective device. With any strong irritation, the ciliate throws out the trichocysts, they turn into thin long threads and infect the predator attacking the shoe. Trichocysts are located between the cilia, they are as numerous as the latter, so they represent a powerful defense. In place of the “shot” trichocysts, new ones are formed.
The movement of ciliates shoes
The shoe, like all living organisms, reacts to changes in the external environment by changing the direction of movement. If a piece of bacterial film is placed in a drop of water where the shoes are floating, then all the protozoa gather near it, since the bacteria secrete various substances into the water, which signal to the ciliates about the presence of food in this place. If you put a crystal of table salt in a drop, then the shoes float away from this unfavorable factor. Protozoa behave very interestingly under the influence of electric current. If a weak electric current is passed through the liquid where these animals swim, all the shoes line up along the current line, and then, as on command, they begin to move towards the cathode, where they accumulate.
Reproduction of infusoria shoes
With good nutrition, shoes multiply quickly. Cultivated artificially in cages, they give a mass of 20 to 104 grams per cubic meter. Even a one-time introduction of a suspension of these ciliates into fish ponds at the rate of 5-10 grams per tenth of a hectare increases the survival rate of fry from 50 to 67%. Under experimental conditions, it is possible to obtain a density of ciliates of shoes up to 50 thousand individuals per cubic centimeter, that is, 50 million individuals per cubic meter.
The biochemical analysis carried out shows that the protein of the fresh mass of ciliates contains all essential amino acids, i.e. It is of high quality and is close in composition to casein. Tasting the dry mass of ciliates showed that the taste of these protozoa resembles the taste of dried cottage cheese or chicken meat.
Features of ciliates shoes
Ciliates are even amenable to "training". Scientists have put interesting experience. When the shoe, which was in the dark, crossed the border between light and dark, it received a blow. electric shock. The animal reacted to this by momentarily stopping and turning back. Already after 45 minutes of training, ciliates on the border between darkness and light were sharply turned back, without waiting for an electric shock. It is possible to develop in ciliates and reactions of getting used to any constant stimuli, for example, to vibration. Such acquired reactions were stored in the "memory" of the shoes from 8 minutes to 1.5 hours. Such experiments show that infusoria can accumulate individual experience during their life, which, of course, is an adaptation to changing environmental conditions. Recall that ciliates are unicellular animals that do not have nervous system and even any cell organelles similar to it. Memory in this case is apparently formed due to purely molecular interactions.
Infusoria shoes have a very subtle chemical sense. They distinguish thousandths of a percent of dissolved salts and acids in water and millionths of a percent of toxic substances contained and heavy metals. Therefore, laboratories often use ciliates to detect certain impurities in water.
Shoes, when possible, choose certain favorable temperature conditions. If they are placed in a tube with water, where the temperature at one end is 35 degrees, and at the other 15 degrees, then the shoes are collected in a zone of 24-26 degrees that is favorable for them.
In nature, shoes live in small freshwater reservoirs. These ciliates are very easy to breed in an aquarium if you fill a bunch of ordinary hay with pond water. In such tinctures, many ciliates develop, including relatives of the shoe - trumpeter ciliates.
The simplest unicellular organisms belonging to the class of ciliates are distributed almost everywhere. From the cold ice of the North to the no less burning icebergs of the South, in any stagnant water, these cute creatures are found, which are one of the most important links in the food chain of the biocenosis. For the ciliate aquarist, shoes are valuable as a good food supplement for newborn fry. But before you wind up in your " underwater world» this living creature, it is worth getting acquainted with the reproduction, nutrition and vital activity of the microorganism.
Natural habitat and beyond
The smallest of living things live in shallow pools of still water. Infusoria shoes are so named for the similarity of the shape of the body, completely covered with cilia, with a lady's shoe. Cilia help animals move, eat, and even defend themselves. The smallest organism has a size of 0.5 mm, it is impossible to see ciliates with the naked eye! An interesting way to move in the water is only with a rounded blunt end forward, but even with such a kind of “walking”, the babies develop a speed of 2.5 mm / 1 second.
Unicellular creatures have a two-core structure: the first "large" nucleus controls the nutritional and respiratory processes, monitors metabolism and movement, but the "small" nucleus is included only in the processes of sexual significance. The thinnest shell of increased elasticity allows the microorganism to be in a natural, clearly defined form, as well as to move quickly. As such, movement is carried out by means of cilia, which play the role of "oars" and constantly push the shoe forward. By the way, the movements of all cilia are absolutely synchronous and coordinated.
Vital activity: nutrition, respiration, reproduction
Like all free-living microorganisms, the shoe infusoria feeds on the smallest bacteria and particles of algae. Such a crumb has an oral cavity - a deep depression located in a certain place on the body. The mouth opening goes into the pharynx, and then the food goes straight into the vacuole for digestion of food, and then the food begins to be processed acidic, and then alkaline environment. The microorganism also has a hole through which incompletely digested food remains come out. It is located behind the food opening and, passing through a special type of structure - powder, the remnants of food are pushed out. The nutrition of the microorganism is debugged to the limit, the shoe cannot overeat or remain hungry. This is perhaps one of the perfect creations of nature.
The ciliate shoe breathes with all the covers of its body. The released energy is enough for the life support of all processes, and unnecessary spent compounds, such as carbon dioxide, are also removed by the entire area of the body of the individual. The structure of the ciliates of the shoe is quite complex, for example, contractile vacuoles when overflowing with water with dissolved organic matter, rise to the very extreme point plasma on the body and push out everything unnecessary. Freshwater inhabitants thus remove excess water, which constantly enters from the surrounding space.
Microorganisms of this type can gather in large colonies to places where a lot of bacteria accumulate, but they react extremely sharply to table salt- float away.
reproduction
There are two types of reproduction of microorganisms:
- Asexual, which is the usual division. This process occurs as a section of one infusorian shoe in two, and new organisms have their own large and small core. At the same time, in new life only a small part of the "old" organelles passes, all the rest are quickly formed anew.
- Sexual. This type is used only when temperature fluctuations, food insufficiency and other unfavorable conditions appear. It is then that the animals can separate into sexes and then turn into a cyst.
It is the second breeding option that is most interesting:
- Two individuals temporarily merge into one;
- At the confluence, a kind of canal is formed, connecting the pair;
- The large nucleus completely disappears (in both individuals), and the small one is divided twice.
