Euglena green: simple and clear - structure, nutrition, reproduction, photo, video

Description and characteristics. What does green euglena look like?

Signs

Structure

Habitat

Nutrition

Organoids

Reproduction

Description and characteristics. What does green euglena look like?

The body of green euglena consists of twenty

chloroplasts, which contain chlorophyll, which is involved in photosynthesis. Chloroplasts are green plates and in general they are only present in cells with a nucleus in the center. And thanks to them, euglena is green and is called “green”, due to chloroplasts and chlorophyll it is really bright green.

This is what green euglena looks like when you look at it under

microscope.

If during the day euglena receives energy from sunlight through the process of photosynthesis, then at night it feeds on organic matter from the water. The water itself must be fresh. Therefore, euglena is found in fresh water bodies: ponds, lakes, rivers, swamps.

In appearance, euglena is similar to algae, and would be such a unicellular algae, if not for several nuances. Firstly, heterophoric night feeding of euglena is characteristic of animals, but not plants. In addition, there are other signs that euglena belongs to animals:

Ability for active movement. Euglena moves with the help of a special flagellum, its rotational movements ensure its mobility. Euglena always moves progressively, by the way, in this moment it differs from another simple unicellular organism -

ciliates are slippers, whose movements are always smooth due to the large number of small cilia.

Special pulsating vacuoles are another sign that euglena belongs to the animal kingdom; their structure is similar to muscle fibers, which animals, but not plants, possess.

The presence of an oral funnel is another evidence of euglena as an animal. But it is worth noting that euglena still does not have a mouth opening as such. Simply in an attempt to capture organic food, the euglena seems to press part of its outer membrane inward. Food is retained in the compartment created in this way.

Due to all these points, there is still no consensus in the scientific community about where Euglena green belongs: to plants or animals. Most scientists still classify it as a flora, seeing it as a unicellular algae, 15% of biologists consider it an animal, the rest see it as an intermediate species.

Colacium

Euglena genus colacium on crustacean.
Microscope magnification 200x and 400x On crustaceans, you can often find ciliates in the role of epibionts (i.e., organisms that live on the surface of other organisms), but in this case they are euglena protists Colacium. They are the only genus of euglena that lead an attached lifestyle, settling on small planktonic animals.

In their development cycle there is a motile stage during which they have a flagellum and look like a typical euglena, but when they find a host, the flagellum is shed and a mucous stalk is formed for attachment to the body of the animal.

Signs

The body of our heroine is spindle-shaped with a hard shell. The average body length of euglena is 0.5 mm. The front part of the body is blunt and has a red eye. This eye is photosensitive and allows its owner to find “feeding” places during the day, in other words, “it leads the euglena to the light.” In any body of water, these microorganisms always gather in the brightest places. By the way, a large number of euglena in a given body of water makes the surface of the water reddish, even brown. Such an unusual effect from the accumulation of euglena was observed and described in his works by the great naturalist of antiquity, Aristotle, in the 4th century BC. e.

At the anterior end of the body of a unicellular organism there is a flagellum. Moreover, in newborn organisms the flagellum may be absent, since the cell is divided into two and the flagellum remains on only one of the parts. On the second euglena it will grow back over time.

The rear end of the green euglena's body, on the contrary, is pointed; this shape improves streamlining, and therefore speed.

Interestingly, green euglena is characterized by metabolism, that is, the ability to change body shape. Despite the fact that, as a rule, euglena are fusiform, in different circumstances they can take other forms, be:

like a cross
rolled,
spherical,
lumpy.

But regardless of the body shape of the green euglena, its flagellum will be invisible if the cell is alive. And he is invisible for the reason that the frequency of his movements is so fast that the human eye is simply not able to catch it.

Trachelomonas

Trachelomonas at 1000x microscope magnification
Trachelomonas is a relative of Euglena green, a flagellate living in a house called a lorica.

The lorica has a hole surrounded by a neck, from which a long flagellum emerges. You can see the chloroplasts and the red eye - stigma.

It reproduces by binary fission, after which one of the individuals leaves the house through the hole and immediately synthesizes a new lorica for itself. A newly built house is absolutely transparent and colorless. Over time, it acquires a brown tint due to the deposition of iron and manganese salts.

Structure

Summarizing all of the above, we can conclude that green euglena is an animal or plant consisting of:

A flagellum, the very presence of which places our heroine in the class of flagellates. The diameter of the flagellum is on average 0.25 micrometers; it can only be seen through a powerful microscope. The process is covered with a plasma membrane consisting of microtubules that move relative to each other. Their movement causes the general movement of the flagellum.
Eye, also sometimes called stigma. The eye consists of optic fibers and lens-like formations. Thanks to the latter, it captures the light that the lens reflects onto the flagellum. Having received an impulse from it, the flagellum, in turn, begins to move towards the light. The red color of the euglena eye is due to colored droplets of lipid - fat. The peephole itself is surrounded by a membrane.
Chromatophore are special pigmented cells and plant components responsible for its color; in euglena they are bright green.
Peplicula is a Latin word that means “skin.” Euglena peplicules, consisting of flat membrane vesicles, form the shell of this simplest single-celled organism.
A contractile vacuole, which is located just below the base of the flagellum. This contractile vacuole is a kind of analogue of muscle tissue. In the structure of the euglena, it is responsible for pushing out excess water from the cell, due to which the euglena maintains its constant volume.

This is how the structure of green euglena looks in the picture.

A few more words about the contractile vacuole, with its help the respiration of green euglena is also carried out.

Habitat

Euglena lives only in fresh water bodies, especially preferring those where the water is dirtier. In reservoirs with clean water, euglena is either small in number or completely absent. In this respect, euglena is similar to its other single-celled “colleagues”: amoebae and ciliates, which also love dirty water.

Since euglena are quite resistant to cold, in addition to fresh water they can live in harsh conditions of ice and snow.

It is worth noting that green euglena can be dangerous, as living in putrefactive water, it sometimes serves as a carrier of trypanosomes and leishmania. The latter is the causative agent of some skin diseases. Trypanosomes can cause African sleeping sickness, which affects the nervous and lymphatic systems, leading to fever.

If euglena gets into aquarium water, then such water will bloom, so it is not without reason that aquarists consider euglena a dangerous parasite and try to get rid of it. You can get rid of green euglena using special chemicals (remembering to move the fish to another place during this time). And, of course, do not forget about regular water replacement and filtration, then the water in the aquarium will be fresh and clean and euglena will not grow in it.

How to try to get rid of an unwanted guest?

How to approach such a problem?
After all, we often hear that water has sufficient cleaning power to cope with its own contaminants. To a certain extent this is true, but only applies to large natural bodies of water. Artificial conditions, and, most importantly, a small amount of water, will not make it possible to defeat such an uninvited guest. After all, it does not need food, it is an autotroph, and reproduction occurs quickly and easily.

You can try to defeat newly emerging blue-green algae, including oscillatorium, with the help of bottom orderlies - ancistrus. These beloved creatures belong to the catfish species, which naturally clean surfaces in their common aquatic home. They are not only funny, but also useful.

Blue-green algae is a bacteria that must be combated in several ways:

create conditions contrary to the algal world;
determine and implement a water disinfection method;
thoroughly rinse the soil and clean all affected surfaces;
disinfect the plants and rinse them thoroughly in cold running water;
take measures to ensure that the blue or greenish representative of single-celled algae does not reappear.

Step by step, the essence of these actions of the aquarist comes down to the following.

Remove as many inhabitants from the affected aquarium as possible;
If possible, remove objects that are important for the growth of cyanobacteria;
Change at least half of the water volume, replacing it with fresh, oxygen-enriched water;
Well-rooted plants can be left untouched, but small and floating ones should be removed and sanitized in an accessible way;
Add an antibiotic to the water, for example, erythromycin at the rate of 3-5 mg per 1 liter;
Completely shade the aquarium and leave it without access to light for 72 hours;
At the end of the exposure, change a third of the water again and open it to light.

Before repopulating the fish, it is worth observing how effectively the remediation was carried out. If there are traces of cyanobacteria, it is better to repeat the procedure in time.

With such actions, you can simultaneously fight not only blue-green algae, but also other harmful phenomena in the aquarium, such as xenococus.

For small aquariums, general recommendations cannot be considered optimal. Their main difference is that changing some of the water, the amount of which is already limited, will not be enough. For such a case, it is proposed to get rid of the plant pest using hydrogen peroxide. You need to determine its dose based on the volume of the aquarium: 20-25 ml of peroxide is added proportionally to 100 liters. Most likely, the treatment from oscillators will not end at once, and after 24 hours it is advisable to repeat it.

Further tactics are determined by the intensity of cyanobacteria development. If necessary, after several days, the treatment is carried out again.

Disinfecting with hydrogen peroxide is more difficult, since in this case the presence of fish and plants is completely excluded. For them, this chemical is life-threatening.

Nutrition

As we wrote above, the nutrition of this creature is half heterotrophic and half autotrophic, that is, both due to solar energy and due to organic matter. This unusual, mixed type of nutrition, characteristic exclusively of the life activity of green euglena, is called mixotrophic by biologists.

During the day, euglena is under the Sun, it is not in a hurry and inactive, and really, why should it move and wave its flagellum if “food” in the form of sun rays falls on you itself. But if a euglena finds itself in some dark reservoir hidden from the Sun, and also at night, then it transforms from a plant into an animal, its flagellum begins to actively move, moving its owner around the reservoir in search of organic “food”.

Therefore, if during the day euglena are located only in the light parts of the reservoir, and usually close to the surface of the water, then at night they spread throughout the entire reservoir.

How to protect an aquarium from such a problem?

Blue green algae are plants that in their structure belong to the kingdom of bacteria, although they are not eukaryotes. Therefore, you can bring them into the aquarium with:

new equipment;
contaminated soil;
bushes of plants;
water.

There is evidence that even tap water can serve as a carrier of microscopic pieces of algae. In this case, immediately from the first days of equipping the aquarium, a dark green film will appear on its surface, which has a sharp, unpleasant odor. The water will not be clear and safe, and the introduction of living creatures into it can lead to death.

If plants are taken for transplantation from an aquarium in which the glass is covered with a slippery dark green coating, most likely the ecological system in it is disturbed and the likelihood of the presence of cyanobacteria is high. Such a plant grows poorly because it does not absorb minerals, looks sickly and quickly withers.

Soil with growing cyanobacteria is poorly ventilated, has a low oxidation rate, and releases toxic gases into the water - waste products of blue-green algae.

It is very important that the water contains no residues of organic substances such as amino acids and carbohydrates formed during the decomposition of food residues. Therefore, it is necessary to strictly observe the feeding regimen and the amount of this feed.

Mechanical contaminants suspended in water are easily removed using special devices - filters.

A third of the water in the aquarium should be changed regularly (at least once every 10 days). The coefficient of oxygen saturation is important, i.e. aeration. The power of the air pump must correspond to the available volume of liquid.

Another important risk factor is excessive lighting. According to many biologists, fish do not need long daylight hours. Lighting is rather a characteristic necessary for plant growth and solving design ideas. But along with cultivated underwater plants, blue-green algae grow, especially if the water temperature is unreasonably high. Therefore, the number of hours when direct light is directed into the aquarium must be balanced.

The tasks of an aquarist include such unpleasant aspects as the fight against blue-green algae. And along this path, you can achieve good results if you follow generally accepted rules of hygienic care for fish and their habitat.

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Organoids

Organelles or organelles are the permanent or specialized structures of every cell, both animal and plant. As for the organelles of green euglena, they have already been listed above, in the section on the structure of euglena. Each of these organelles or organelles is a vital element of a single-celled organism, without which it would not be able to eat, move, reproduce and generally exist.

Blue-green algae - the pinnacle of bacterial evolution

Photosynthesis of cyanides occurs in the same way as in plants, which distinguishes them from other prokaryotes, as well as fungi, raising them to the highest degree of evolutionary development. They are obligate phototrophs, as they cannot exist without light. However, some have the ability to fix nitrogen and form symbioses with higher plants (like some fungi), while maintaining the ability to photosynthesize. It has recently been discovered that these prokaryotes have thylakoids that are separate from the folds of the cell wall, like eukaryotes, which makes it possible to draw conclusions about the direction of evolution of photosynthetic systems.

Other known symbionts of cyanides are fungi. In order to survive together in harsh climatic conditions, they enter into a symbiotic relationship. Fungi in this pair play the role of roots, receiving mineral salts and water from the external environment, and algae carry out photosynthesis, supplying organic substances. The algae and fungi that make up lichens could not survive separately in such conditions. In addition to symbionts such as mushrooms, cyanians also have friends among sponges.

Reproduction

Would you like, dear reader, to live forever? This is a philosophical question, and you may be surprised, but in biology there is an example of “infinite life”, and yes, our today’s heroine, Euglena, is this example. The lifespan of green euglena is essentially endless! And all because of the method of its reproduction, which is carried out exclusively through cell division. So the euglena that you can see today in some green pond or swamp was created through division from a certain euglena that lived in the era of dinosaurs, or even earlier.

But the time that euglena remains indivisible is, on the contrary, extremely short, amounting to only a few days. Then the euglena begins to divide, then divide again, and so on ad infinitum.

As for the division of euglena itself, it occurs in several stages, it all begins with the division of the cell nucleus. Two new nucleoli diverge on opposite sides of the cell, after which the cell itself begins to divide in the longitudinal direction. Cross division is not possible.

This is how the division of euglena looks schematically.

The divided membrane closes on each half of the cell. Thus, from one euglena you get two. In a favorable environment, these creatures can reproduce in arithmetic progression.

Amoeba

“The path from amoeba to man seems to some to be an obvious progression, but it is not known whether amoeba agrees with this opinion.”

Bertrand Russell, British philosopher

Amoeba is a freshwater representative of the rhizome class. Unlike many protozoa, it does not have a constant body shape. Its only cell is constantly transforming. The amoeba moves with the help of pseudopods.

The pseudopods also serve to capture food - bacteria, unicellular algae and some of the simplest relatives of the amoeba. Having grabbed the victim with its pseudopods, the amoeba seems to swallow it. The prey ends up in the cytoplasm, where a digestive vacuole forms around it. Under the influence of digestive juice coming from the cytoplasm, food is digested. Nutrients penetrate into the cytoplasm, and undigested residues are thrown out.

AMOEBA - PROTEUS
Amoeba was first described and drawn by the German naturalist Johann Rösel von Rosenhof. He named her Proteus - in honor of the ancient Greek god who changes his appearance at will. Since then, “amoeba” has been a symbol of something simple, artless and narrow-minded.

Amoeba reproduces by division. The nucleus divides in two, both halves diverge, and a constriction forms between them. Then two daughter cells arise from one mother cell. After the division process is completed, they continue to live independently, independently of each other.

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Author: Pavel Chaika, editor-in-chief of Poznavaika magazine

When writing the article, I tried to make it as interesting, useful and high-quality as possible. I would be grateful for any feedback and constructive criticism in the form of comments on the article. You can also write your wish/question/suggestion to my email [email protected] or Facebook, with respect, the author.

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