Yesterday, not far from the garden, I scooped up some water in a shallow swamp. I chose a place as dark and smelly as possible in order to catch more living creatures. The main targets were small crustaceans such as daphnia and cyclops. When I looked at a drop of this water in more detail, I saw very small and nimble organisms. In addition to the shell with moving cilia, large organelles for some reason brown and green were clearly visible inside. The basic shape of these small organisms was elliptical, but with some turns a profile resembling a shoe print was clearly visible. Yes, that's for sure ciliate, perhaps even of the kind paramecium (ciliates-slippers, Paramecium). The video clearly shows how they swarm next to pieces of silt, trying to force bacteria and other small organic matter into their throats with pulsating cilia. In the presented video, the first half a minute was filmed at low magnification, and the ciliates look like small, swarming dots, and then the magnification is several times stronger, and their shape can be seen in detail.

Ciliates, or ciliated (lat. Ciliophora) are a type of protozoa from the Alveolata group. The body shape of ciliates can be varied, the sizes of single forms range from 10 microns to 4.5 mm. They live in seas and fresh water bodies as part of benthos and plankton, some species live in the interstitium, soil and mosses. The name "ciliate" comes from lat. infusum (“tincture”) according to the place of initial discovery of the protozoa - in herbal tinctures.

Paramecium, or slipper ciliates (lat. Paramecium) is a genus of ciliates that includes several hundred species, including many twin species. The body length of various representatives ranges from 50 to 350 micrometers. Cells in the shape of a shoe (hence the popular name - “slipper ciliates”). They usually live in fresh rivers and ponds.

The paramecium cell consists of a hard pellicle, i.e. a plasma membrane with an underlying layer of flat vacuoles (alveoli), which surrounds the cellular contents - the cytoplasm. The surface is covered with hair-like structures - cilia, with the help of which paramecia swim. The light outer layer of cytoplasm (ectoplasm) contains spindle-shaped structures called trichocysts. When the paramecium is exposed to a strong irritant or attacked by another organism, the trichocysts “shoot” long protein filaments from the cell. Perhaps this is a defense mechanism.

The granular internal cytoplasm (endoplasm) contains one large nucleus (macronucleus), one or more small nuclei (micronuclei), digestive vacuoles and two contractile vacuoles. On the side of the cell is the oral cavity. The wave-like beating of the cilia lining it drives food particles deeper into the “throat”. At the end of it, a digestive vacuole is formed at the endoplasmic level. It separates from the pharynx, migrates along a certain route in the cytoplasm, digesting the material, then throws out undigested remains through a certain surface area behind the oral cavity, called the anal pore, and at the same time is destroyed.

Paramecia feed on protozoa, bacteria and algae. Metabolic waste is removed diffusely across the entire surface of the cell, and contractile vacuoles (one at each end of the paramecium) regulate its water content.

Asexual reproduction of Paramecium occurs by division in two. First the nuclei divide. Then a transverse constriction is formed on the cell, which deepens and divides it into two daughter cells, identical to each other and to the mother. The sexual process is called conjugation and reproduction in itself is not. Two cells of the same type are connected by a temporary cytoplasmic bridge, exchange copied micronuclei material and diverge.

In some species, endomixis is observed: a complete restructuring of the nuclear apparatus inside the cell, when the macronucleus is destroyed, and the micronucleus divides and restores it from its material. In both cases, several cell divisions usually occur immediately after nuclear reorganization.

Ciliate slipper - photo, maintenance, breeding

Date: 2011-09-12

Ciliate fish food

The ciliate slipper is an excellent food for fry of aquarium fish. You cannot do without ciliates if you decide to start breeding aquarium fish. You will have to feed your newborn dependents with the smallest food possible. In the summer, experienced aquarists will advise looking for such food in the nearest body of water, taking.

But, unfortunately, the current state of the environment in industrial centers is almost guaranteed to predetermine the failure of such a pastime. Within the boundaries of large cities, everything has been poisoned for a long time and irrevocably, and even if it has not died out, it is hardly suitable for feeding tender young. It is not without reason that aquarium breeding specialists spend almost days driving their own cars around the distant Moscow region in search of a “live” puddle. Of course, I will advise you something simpler.

Photo Infusoria - slipper

Once a neighbor boy came to me to look at the fish in the aquarium, and at the same time told me a story that happened in their class. The teacher gave the task to draw the inhabitants of another planet, creatures of another civilization. As a result, no one came up with anything original, but the mentor was not upset. He was simply once again convinced that when performing such tasks, children use characteristic images of certain earthly animals in their creativity. Human and even children's imagination cannot give birth to a creature that is decisively different from the earthly one. This school problem could be solved more successfully if the subjects were familiar with the world of Protozoology.

The inhabitants of this world cannot be seen with the naked eye; at best, you can see in the water some tiny whitish specks, tiny dots perceived as dregs. Most people only know about these creatures that they are extremely small. But for an aquarist they can be of practical interest.

On Earth there are a host of simple organisms that represent a single living cell. Among them are ciliates. The sizes of these animals are very small and range from a few microns to 2 millimeters, so that with almost complete certainty they can be attributed to the world of invisible people. Scientists count more than 6,000 species of ciliates, and most likely, not all of them have yet been identified and found a place in zoological nomenclature.

It must be admitted that many aspects of the biology of ciliates remain a mystery to people. The study is complicated by their small size and themes. that the maintenance and reproduction of the vast majority of unicellular organisms “in captivity” has not yet been mastered.

How do they look? These are people from another world. You will not find a head and a tail on them, although the concept of “front-back” exists for them. There are no legs, paws, fins, wings, eyes, ears. They don't have a voice either.

There is no heart, lungs, liver, kidneys, intestines, etc. There is no nervous system and genital organs in the form that is characteristic of animals, birds, fish and reptiles. Is there at least something close to human concepts, familiar to our eyes? Only the mouth and defecation device (powder), and even then not all of them, some of them feed on the whole body.

However, ciliates live and thrive and solve all biological problems with their own, often incomprehensible to us, techniques. We, aquarists, are mainly interested in one of the largest representatives of this class, namely the slipper ciliate known to everyone from school - Paramecium caudatum. Using her example, I will briefly tell you what kind of animal this ciliate is.

This ciliate received its popular name “slipper” for its slight resemblance to the shape of a shoe’s footprint. Its streamlined contours are the result of adaptation to an aquatic lifestyle. The size of an adult reaches 0.3 millimeters. The unicellular body is covered with a multilayer structured shell, quite strong and elastic.

She can move at speeds of up to 2.5 mm/sec, covering a distance of 10 times the length of her own body during this time. She maneuvers very deftly, instantly changes the direction of movement, and can swim backwards. The entire surface of the ciliate is covered with cilia, the coordinated rowing movements of which ensure the mobility of the animal.

In all images of the shoe you can see a certain internal star-shaped organ. This is the so-called contractile vacuole with ampoules located around it. The main purpose of this device is to pump out the liquid constantly flowing through the shell. The concentration of dissolved substances in the body of the shoe is higher than in the environment, therefore, due to the difference in osmotic pressure, water rushes in and, if it is not pumped out, the ciliate will simply burst.

The liquid first fills the ampoules, which at some point are emptied into a contractile vacuole, which inflates into a vesicle. Then the water is thrown out through a special channel. The slipper has two contractile vacuoles; they pulsate alternately with a frequency of once every 20-25 seconds. It is assumed that with the help of this device the shoe also regulates its ionic composition, getting rid of, in particular, excess sodium ions. It is possible that this water exchange also has respiratory functions.

Inside the ciliates, in special vacuoles (vesicles), crystals are found, consisting mainly of calcium and phosphorus salts; magnesium, chlorine and organic components are found in smaller quantities. The purpose of these formations is mysterious.

What does the ciliate slipper eat?

The slipper ciliate feeds mainly on bacteria, as well as yeast, algae, dissolved protein substances, etc. Its mouth is located on its side, in a recess at the end of a special groove running along the front of the body.

The cilia intensively drive water along with food to the mouth. Then the collected particles are enclosed in a special digestive vacuole - a small closed container (bubble) with digestive enzymes, which is separated from the “throat” and circulates inside the ciliate for some time along a certain route, distributing elements suitable for use throughout the cell.

When there is an abundance of food, food vacuoles can form at intervals of 1.5-2 minutes, which indicates a high intensity of digestion. Several vacuoles with undigested residues merge, approach the powder and are expelled.

It can be assumed that by eating bacteria, ciliates carry out a kind of disinfection of water. It is also noteworthy that although the shoe has the ability to distinguish food, it cannot help but swallow any particles driven into the pharynx by the cilia.

Therefore, in its “stomach”, along with bacteria (healthy food), there are tiny particles of paint (carmine, coal), plastic or metal (sawdust), etc. This feature helps to study in laboratory conditions some of the life processes of ciliates. Inedible substances that are swallowed are thrown out much faster than useful substances.

How does the ciliate slipper reproduce?

With good nutrition and optimal environmental conditions, the slipper ciliate reproduces very quickly. A. Mikulin in the brochure “Live Food” (Moscow, “Dolphin”, 1994) reports that to achieve the maximum possible concentration of slippers of 40 thousand copies per cubic centimeter of water from one single individual it takes less than a month. The slipper uses two methods of reproduction: asexual and sexual.

In the asexual method, ciliates reproduce by transversely dividing the body in two. This happens 1-2 times a day. In general terms the process looks like this. The slipper ciliate carries two nuclei in its body - large and small.

The large nucleus is responsible for the correct metabolism in the cell, the small one is the carrier of hereditary information. Before division, the set of chromosomes in the nuclei is doubled, and upon division, each daughter individual receives its own set of two nuclei. They also re-form all other organs. Division takes from 30 minutes to 2-3 hours, depending on the ambient temperature.

Sexual reproduction is associated with the temporary union of two individuals (there are no males or females in the slipper). Ciliates are applied to each other by the sides where the mouth openings are located. At this point, part of the membrane dissolves and the cells are connected by a plasma bridge. In this state, the shoes float for about 12 hours.

Photo Infusoria - slipper

During this time in the body of both ciliates a number of changes are taking place. Large nuclei do not participate in the sexual process and, moreover, disintegrate and dissolve in the plasma. But small ones go through a chain of complex changes and eventually double in size. One of the new nuclei remains in the old place, and the second passes through a plasma bridge into the neighboring cell and there merges with another, “alien” nucleus, after which the ciliates are separated. In this way, genetic material is exchanged.

The matter, however, does not end there. Since the separated ciliate has only a small nucleus, i.e. "incomplete", then it begins to divide according to a complex program, forming both new small and large nuclei.

To distribute the resulting nuclei, the ciliate itself is successively divided twice. Ultimately, from each participant in this “sexual intercourse” four ciliates-slippers with an updated set of genes are obtained. Next, each of them reproduces for some time by simple division, since before the next asexual fusion a certain number of cell divisions must occur and the cells themselves must reach a state of maturity. External factors, such as light, temperature and nutrition, also affect their readiness.

It remains a mystery how the slipper ciliate spreads across water bodies. The vast majority of protozoa can fall into a cyst state, when life processes stop, the cell is clothed in a durable shell, under the protection of which it is able to withstand unfavorable conditions, in particular the drying out of a reservoir, after which these cysts are carried by the wind along with dust. When the cyst gets back into the water, the body awakens to life.

This has been tested in laboratories several times, but... not with a shoe. Neither cystization nor recystation can be achieved, although it would seem that this ciliate is so easily bred in “captivity” that experiments can be repeated endlessly and a certain result can be achieved. There is only one plausible version of dispersal: paramecium is carried by waterfowl and other migratory aquatic animals.

Now about behavior. Ciliates perceive various external stimuli and react to them accordingly. As a rule, the response to irritation is their spatial movement. Irritation can cause purposeful movement towards or away from the source of irritation. Scientists call this reaction topotaxis, or taxis. When an infusoria moves towards a stimulus, they speak of positive taxis; if it avoids it, they speak of negative taxis.

You may have come across this word in aquarium literature before, when the author, wanting to show off his knowledge of scientific terminology, instead of simply writing “newborn fry hide from the light,” informs the reader that they “have negative phototaxis.”

Here are a few concepts from the field of taxi ciliates-slippers.

Responsive to lighting. How and with what she perceives him is unclear today. Laboratory experiments show that they not only have a system for sensing light, but also measure its intensity and even its wavelength, i.e. color. It is believed that slippers usually exhibit positive phototaxis, but my experience in breeding this ciliate and feeding it to fry does not confirm this. I have never noticed that slippers gather near the more illuminated wall of the vessel where they live, or near the surface of an aquarium with fry lit from above.

Photo Infusoria slipper

Most often, in good living conditions, they are simply evenly scattered throughout the volume, regardless of the direction and intensity of light. It has been noted that if a shoe feeds on algae, it tends to go into the darkness. Apparently, the captured, but not yet fully digested algae in the light are engaged in photosynthesis until the last moment, and this somehow interferes with the digestion of the ciliates.

Chemotaxis, or the response to the presence of a chemical stimulus, is not always obvious in slippers, although it is generally accepted that chemoreception, or sensitivity to various chemicals, is of great importance for them in natural conditions. Thus, it is definitely known that ciliates ready for sexual reproduction find each other by secreting certain chemicals.

Mechanotaxis is a response to a solid substrate or fluid flow. An example of negative mechanotaxis is the flight of a shoe when it stumbles upon an obstacle, receiving mechanical irritation. The ciliate reacts positively to the flow of water, i.e. tries to swim against him. It is believed that ciliates mainly perceive mechanical irritation with their cilia.

Interesting experiments with shoes were carried out to determine their geotaxis, that is, the relationship between movements and gravity. It is assumed that they perceive gravity through the pressure exerted on the cell plasma by food vacuoles or vacuoles with crystalline inclusions.

So, the shoes were fed with iron filings, and then they were placed in a magnetic field, and they began to float away from the magnet, exhibiting negative taxis. This imitation of gravity allows us to conclude that their geotaxis is negative. Logic dictates that otherwise they would “sink” and move mainly in the bottom layer.

Ciliates slippers They are undoubtedly capable of sensing temperature, but neither positive nor negative thermotaxis has yet been observed in them. They simply accumulate in the region of optimal temperatures. For a shoe it is 24-28°C.

Another feature of their behavior is that in a medium through which a direct electric current is passed, they float quite purposefully towards the cathode. And although this phenomenon is unlikely to occur in nature, it can be called galvanotaxis.

It's easy to test at home. Two stripped copper wires should be glued to the glass at a distance of several centimeters. Place a few drops of a thick culture of ciliates on glass so that the wires are covered with water, and then connect them to a direct current source with a voltage of 5-9 volts (Krona battery).

Ciliates moving randomly will immediately rush to the negative electrode. Change the poles and they will turn back towards the cathode. The nature of this phenomenon, like many other things in the life of ciliates, has not been clarified to date.

And finally, the most important taxis of the slipper ciliates for aquarium hobby is positive oxygen taxis. With a lack of oxygen, ciliates energetically rush to the surface, where gas exchange at the border of two environments makes it possible to “breathe”. The question of how she breathes and how she feels suffocated also does not have a clear answer. But how this taxis is used by aquarists, I will tell you in more detail below.

Certainly not all aquarists decide to cultivate the slipper at home. The significantly exaggerated, in my opinion, difficulties of breeding and maintaining it are frightening. Of course, it will take some effort, but as you know, only cockroaches live in an apartment without care. Nevertheless, “the devil is not as terrible as he is painted”: an attentive and patient amateur successfully copes with this task.

Photo Infusoria slipper

As a food item, the slipper ciliate, according to publications, is quite attractive. In the already mentioned work of A.E. Mikulin “Live food” a comparative table of the amino acid composition of the protein of various aquatic invertebrates forage is given: ciliates, rotifers, etc. So here it is. The heroine of this article is superior to others in certain indicators.

At the same time, there is a strong opinion among aquarium breeders that “fry do not grow on ciliates.” There is some truth in this statement. In my opinion, it’s all about the quantity or nutritional volume of ciliates. While the fry is still small, it quickly fills its tummy with this food, again if there is enough of it per unit volume of water in the aquarium where the babies are sitting. True, there are fish whose newborn fry are so lethargic and inactive that the speed of movement of the shoe is too high for them; this food may not be suitable for them: they will die of hunger, but will not be able to catch.

And when, after the first 3-4 days of feeding, the baby grows up to the ability to swallow something larger, filling his enlarged tummy with ciliates becomes difficult, especially since during this period the fry is able to eat continuously (and needs it). In nature, the entire “food set” necessary as they grow larger floats along with the fry, and in the conditions of a spawning ground, ensuring such a neighborhood is the concern of the aquarist. Therefore, ciliates are good for the first 3-7 days, and then you need to look for something more satisfying.

However, most of the failures in breeding, if the fry have already hatched, fall precisely on the primary (starter) feeding. Most often, the food does not correspond to the size of the fry: they simply cannot swallow it, they need a living object. Infusoria-slipper in most cases fits perfectly.

It is problematic to breed ciliates for a large aquarium fish farmer. and for amateur purposes, feeding (or rather “raising”) two or three hundred fry of small aquarium fish on your own ciliates will not be difficult.

The most difficult task is to acquire an initial pure culture of paramecium. It is best to get it from a friend or buy it at the Bird Market. In books on aquarium management you can also find the following advice: squeeze a bunch of aquarium plants onto glass and, with good magnification (+5-7D), catch these ciliates with a very thin pipette. For details of how this is done, see the appropriate book. I tried - to no avail.

There are times when a shoe is suddenly bred in mass quantities under unexpected circumstances. I once had to deal with an aquarium in which crabs from Southeast Asia lived. The water level was only about 5 cm, and their diet consisted mainly of fruits (vegetarian crabs). How the shoe got there is unknown, but there was a huge amount of it, and no other protozoa were visible among them: an ideal culture.

Adequate oxygen is important for ciliates. To provide them with such conditions, a container with a maximum surface area is most suitable. For a small amount of paramecia, you can use a three-liter jar half filled with water, preferably soft. I keep ciliates in boiled water with a hardness of 6-8MGH. To obtain water of such parameters, you need to boil tap water, let it settle and drain the top 2/3 of the volume.

It is better to maintain the temperature at 15-18°C (for example, in winter I keep jars of ciliates on the windowsill). This temperature is not optimal for the shoe.

At 24-28°C, although the culture quickly reaches maximum density, it dies just as quickly, being poisoned by the products of its own metabolism (that is, waste products) and unable to withstand respiratory competition with the massively reproducing bacteria that serve as food for the shoes.

I. VANYUSHIN Mytishchi, Moscow region.

Aquarium Magazine 2001 No. 4

The slipper ciliate lives in shallow, stagnant bodies of water. This unicellular animal, 0.5 mm long, has a spindle-shaped body, vaguely reminiscent of a shoe. Ciliates are always in motion, swimming with their blunt end forward. The movement speed of this animal reaches 2.5 mm per second. On the surface of the body they have organelles of movement - cilia. There are two nuclei in the cell: the large nucleus is responsible for nutrition, respiration, movement, metabolism; The small nucleus is involved in the sexual process.

The structure of the ciliate slipper

The body of a ciliate is more complex. The thin elastic shell covering the outside of the ciliate maintains the constant shape of its body. This is also facilitated by well-developed supporting fibers, which are located in the cytoplasm layer adjacent to the membrane. There are about 15,000 oscillating cilia on the surface of the ciliate's body. At the base of each cilium lies a basal body. The movement of each eyelash consists of a sharp stroke in one direction and a slower, smooth return to its original position. The cilia oscillate approximately 30 times per second and, like oars, push the ciliates forward. The wave-like movement of the cilia is coordinated. When a slipper ciliate swims, it slowly rotates around the longitudinal axis of the body.

Life processes

Nutrition

The slipper and some other free-living ciliates feed on bacteria and algae.

Reaction of ciliates to food

Thin elastic shell, ( cell membrane) covering the ciliate from the outside, maintains a constant body shape. There are about 15 thousand cilia on the surface of the body. There is a depression on the body - a cellular mouth, which passes into a cellular pharynx. At the bottom of the pharynx, food enters the digestive vacuole. In the digestive vacuole, food is digested within an hour, first with an acidic and then with an alkaline reaction. Digestive vacuoles move in the body of the ciliate by a current of cytoplasm. Undigested remains are thrown out at the posterior end of the body through a special structure - powder, located behind the mouth opening.

Breath

Breathing occurs through the covers of the body. Oxygen enters the cytoplasm through the entire surface of the body and oxidizes complex organic substances, as a result of which they turn into water, carbon dioxide and some other compounds. This releases energy that is necessary for the life of the animal. Carbon dioxide is removed through the entire surface of the body during respiration.

Selection

In the body of the slipper ciliate there are two contractile vacuoles, which are located at the anterior and posterior ends of the body. They collect water with dissolved substances formed during the oxidation of complex organic substances. Having reached their maximum size, contractile vacuoles approach the surface of the body, and their contents pour out. In freshwater unicellular animals, excess water that constantly enters their body from the environment is removed through contractile vacuoles.

Irritability

Slipper ciliates gather in clusters of bacteria in response to the action of the substances they secrete, but swim away from such an irritant as table salt.

Irritability is the property of all living organisms to respond to stimuli - light, heat, moisture, chemicals, mechanical influences. Thanks to irritability, single-celled animals avoid unfavorable conditions and find food and individuals of their own year.

Reproduction

Asexual

Ciliates usually reproduce asexually - by dividing in two. The nuclei are divided into two parts, and each new ciliate contains one large and one small kernel. Each of the two daughters receives part of the organelles, while the others are formed anew.

Reproduction of ciliates-slippers

Sexual

With a lack of food or a change in temperature, ciliates proceed to sexual reproduction, and then can turn into a cyst.

During the sexual process, the number of individuals does not increase. Two ciliates are temporarily connected to each other. At the point of contact, the shell dissolves and a connecting bridge is formed between the animals. The large core of each ciliate disappears. The small nucleus divides twice. Each ciliate produces four daughter nuclei. Three of them are destroyed, and the fourth is divided again. As a result, two cores remain in each. An exchange of nuclei occurs along the cytoplasmic bridge, and there it merges with the remaining nucleus. The newly formed nuclei form a large and small nuclei, and the ciliates disperse. This sexual process is called conjugation. It lasts about 12 hours. The sexual process leads to renewal, exchange between individuals and redistribution of hereditary (genetic) material, which increases the vitality of organisms.

Life cycle of the slipper ciliate

Further from people in the process of evolution are microorganisms. Bacteria, for example, are single-celled organisms that reproduce by cell division. Cell division occurs in the usual way, where the mother cell is divided into two equal daughter cells. There is no further distinction between parental and offspring cells, so we can assume that these organisms do not age.

If there was no violent death, bacteria would have been immortal until recently. However, aging of the simplest organisms with asymmetric division, in the form of a decrease in reproductive output with age, occurs as they lose the ability to recover and reproduce. On the other hand, some bacteria can form spores and remain in a state of suspended animation for many years. However, despite the basic cellular functions being the same for all living organisms, they have many differences compared to human cells. For example, bacteria have circular chromosomes, do not have mitochondria, etc.

Thus, it is impossible to say specifically how long bacteria live due to the nature of their reproduction.

Life expectancy of ciliates

Sexual genetic recombination, which appeared in the process of evolution in ciliates, can be considered as an adaptation of the genome to the environment with the exchange of genetic information. This process is beneficial in terms of increasing diversity.

Slipper ciliates have both asexual and sexual reproduction. Moreover, sexual reproduction of the slipper ciliates occurs only as a last resort when threats to life appear in the form of lack of nutrition or external conditions.

The emergence of sexual differences relates to the emergence of aging in many evolutionary lines.

Starting with ciliates, in which individual cells are “destined to die.” A process reminiscent programmed death of the body, which is also observed in animals. An example is the protozoan sucking ciliate Tokophrya, without any means of removing waste, which makes death inevitable, especially rapid with abundant nutrition.

How long ciliates live depends on nutrition: from several days to a month.

This form of aging resulting from mechanical limitations in the structure of organisms is called “Mechanical Aging”.

Gerontologists study organisms that can reproduce asexually for hundreds of generations, but eventually achieve the extinction of clones. Finally, numerous species among ciliates do not show any signs of clonal senescence when reproducing by fission.

Examples occur among taxa and radiolarians. In the absence of a sexual phase, many species can reproduce without detecting aging of the clone.

Allows you to see simple microorganisms such as bacteria and ciliates.

The ciliate slipper is the simplest living, moving cell. Life on Earth is distinguished by the diversity of living organisms that live on it, sometimes having a complex structure and a whole set of physiological and vital features that help them survive in this world full of dangers.

But among organic beings there are also such unique creatures of nature, the structure of which is extremely primitive, but it was they who once upon a time, billions of years ago, gave impetus to the development of life and from them more complex organisms arose in all their diversity.

The primitive forms of organic life that now exist on earth include ciliate slipper, belonging to single-celled creatures from the alveolate group.

It owes its original name to the shape of its spindle-shaped body, which vaguely resembles the sole of an ordinary shoe with a wide blunt end and a narrower end.

Such microorganisms are considered by scientists to be highly organized protozoa. class of ciliates, shoes are its most typical variety.

The shoe owes its name to the ciliate due to the structure of its body in the shape of a foot.

Slippers are usually found in abundance in shallow fresh water bodies with calm, standing water, provided that this environment contains an abundance of organic decomposing compounds: aquatic plants, dead living organisms, ordinary silt.

Even a home aquarium can become an environment suitable for their life, but such living creatures can only be detected and examined carefully under a microscope, using silt-rich water as a test sample.

Ciliates slippers – protozoa living organisms, otherwise called paramecium caudate, are indeed extremely small, and their size is only from 1 to 5 tenths of a millimeter.

In fact, they are separate, colorless biological cells, the main internal organelles of which are two nuclei, called: large and small.

As seen in the enlarged photo of ciliates shoes, on the outer surface of such microscopic organisms there are, arranged in longitudinal rows, tiny formations called cilia, which serve as locomotion organs for the shoes.

The number of such small legs is huge and ranges from 10 to 15 thousand; at the base of each of them there is an attached basal body, and in the immediate vicinity there is a parasonal sac, retracted by a protective membrane.

The structure of the ciliate slipper, despite its seeming simplicity upon superficial examination, it has quite a lot of complexities. On the outside, such a walking cell is protected by a thin elastic shell, which helps its body maintain a constant shape. As well as protective supporting fibers located in the layer of dense cytoplasm adjacent to the membrane.

Its cytoskeleton, in addition to all of the above, consists of: microtubules, alveolar cisterns; basal bodies with cilia and, located nearby, without them; fibrils and filaments, as well as other organelles. Thanks to the cytoskeleton, and unlike another representative of the protozoa - amoebas, ciliate slipper unable to change body shape.

The character and lifestyle of the ciliate slipper

These microscopic creatures are usually in constant wave-like motion, picking up speeds of about two and a half millimeters per second, which for such tiny creatures is 5-10 times their body length.

Movement of the ciliate slipper It is carried out with its blunt ends forward, while it tends to rotate around the axis of its own body.

The shoe, sharply waving its cilia-legs and smoothly returning them to their place, works with such organs of movement as if they were oars in a boat. Moreover, the number of such strokes has a frequency of about three dozen times per second.

As for the internal organelles of the shoe, the large nucleus of the ciliate is involved in metabolism, movement, respiration and nutrition, and the small one is responsible for the reproduction process.

The respiration of these simplest creatures is carried out as follows: oxygen enters the cytoplasm through the integument of the body, where, with the help of this chemical element, organic substances are oxidized and converted into carbon dioxide, water and other compounds.

And as a result of these reactions, energy is generated that is used by the microorganism for its life activity. After all, harmful carbon dioxide is removed from the cell through its surface.

Features of ciliates slippers, like a microscopic living cell, lies in the ability of these tiny organisms to respond to the external environment: mechanical and chemical influences, moisture, heat and light.

On the one hand, they tend to move to accumulations of bacteria to carry out their life activities and nutrition, but on the other hand, the harmful secretions of these microorganisms force the ciliates to swim away from them.

The shoes also react to salty water, from which they rush to get away, but they willingly move towards warmth and light, but unlike euglena, ciliate slipper so primitive that it does not have a light-sensitive eye.

Nutrition of ciliates slippers

Plant cells and various bacteria, found in abundance in the aquatic environment, form the basis feeding ciliates slippers. And it carries out this process with the help of a small cellular cavity, which is a kind of mouth that sucks in food, which then falls into the cellular pharynx.

And from it into the digestive vacuole - an organelle in which organic food is digested. Substances ingested are subjected to hour-long treatment when exposed to first an acidic and then an alkaline environment.

After this, the nutritional substance is transferred by cytoplasmic currents to all parts of the ciliate’s body. And waste is removed out through a peculiar formation - powder, which is placed behind the mouth.

In ciliates, excess water entering the body is removed through contractile vacuoles located in front and behind this organic formation. They collect not only water, but also waste materials. When their number reaches a maximum value, they pour out.

Reproduction and lifespan

The process of reproduction of such primitive living organisms occurs both sexually and asexually, and the small nucleus is directly and actively involved in the reproduction process in both cases.

The asexual type of reproduction is extremely primitive and occurs through the most common division of the organism into two parts that are similar to each other in everything. At the very beginning of the process, two nuclei are formed inside the ciliate’s body.

After which a division occurs into a pair of daughter cells, each of which receives its part organelles of ciliates slippers, and what is missing in each of the new organisms is formed anew, which makes it possible for these protozoa to carry out their life activities in the future.

These microscopic creatures usually begin to reproduce sexually only in exceptional cases. This can happen when life-threatening conditions suddenly arise, such as a cold snap or a lack of nutrition.

And after the described process has been carried out, in some cases, both microorganisms involved in contact can turn into a cyst, plunging into a state of complete anabiosis, which makes it possible for the body to exist in unfavorable conditions for a fairly long period, lasting up to ten years. But under normal conditions, the life of ciliates is short-lived, and, as a rule, they are not able to live for more than a day.

During sexual reproduction, two microorganisms join together for some time, which leads to a redistribution of genetic material, resulting in an increase in the vitality of both individuals.

Scientists call this state conjugation and lasts about half a day. During this redistribution, the number of cells does not increase, but only hereditary information is exchanged between them.

During the connection of two microorganisms, the protective shell between them dissolves and disappears, and in its place a connecting bridge appears. Then the large nuclei of two cells disappear, and the small ones divide twice.

This creates four new nuclei. Then all of them, except one, are destroyed, and the latter is again divided in two. The exchange of the remaining nuclei occurs along the cytoplasmic bridge, and from the resulting material, newly born nuclei, both large and small, arise. After which the ciliates disperse from each other.

The simplest living organisms perform their functions, ciliates slippers They destroy many types of bacteria and themselves serve as food for small invertebrate animal organisms. Sometimes these protozoa are specially bred as food for the fry of some aquarium fish.