Cyanobacteria are often called. Department of Cyanobacteria. General characteristics of the department. Cell structure, nutrition, reproduction. Representatives. Distribution and significance. Types of trichomes by cell differentiation

1

Differences from bacteria

Are unable to assimilate organic
exogenous compounds
The presence of two photo systems located on
membranes of specialized structures -
thylakoids.
Possibility of flow of two
mutually exclusive processes - oxygenic
photosynthesis and anaerobic nitrogen fixation
Absence of flagella or flagellar stages.
2

In morphological terms, they are represented by the following forms:

Unicellular. Selected
cells function like
independent organisms.
Colonial. Individual cells
unite in colonies in which
binder is
slime.
Unicellular and
colonial
forms have
coccoid type
organizations for
whom
are characteristic
motionless,
dressed
shells
cells.
3

Single cells
Synechocystis
(Chroococcales)
Microcystis colonies
(Chroococcales)
4

Multicellular.
They have a filamentous type of organization.
The morphological unit of these cyanines
is a trichome - a filamentous formation,
consisting of several rows symplastic
(by means of plasmodesmata -
microscopic plasma bridges)
connected cells. Trichome may be
branched and unbranched.
5

Trichomes in multicellular forms

Branched, for example
Fischielopsis (Stigonematales)
Unbranched, for example
Anaebena (Nostocales)
6

Types of trichomes by cell differentiation

Homocytic - all
cells are the same
form and function
Heterocytic - cells
different in shape and
functions
7

Heterocytic trichome cells

Vegetative (the same as in homocytic
trichomes)
Akineta (resting spores) - necessary
for breeding
Heterocysts - responsible for fixation
atmospheric nitrogen.
Apical cells. Only morphologically
progressive forms. Growth is due to them
the most difficultly differentiated
thalli.
8

Cell wall

35 to 50 nm. The thickest in akinet and
heterocysts. Similar in structure to that of
gram-negative bacteria.
Murein is a specific peptidoglycan. Have
some species have calcium deposits. Have
many - mucous membranes and sheaths.
9

10. Murein

10

11. Spare substances

Glycogen-like polysaccharide
Cyanophycin is a nitrogen-containing polypeptide.
Found only in blue-green algae
11

12. Cyanobacteria do not have:

Complete chloroplasts
Mitochondria
Kernels
12

13. Pigments

Chlorophyll a (in prochlorophyll algae
chlorophyll is found b).
Carotenoids (beta-carotene and zeaxanthin,
specific carotenoids -
mixoxanthophyll, oscillaxanthin,
as syntaxanthin and echinenone).
Phycobilins (absent in prochlorophyllic
algae): phycocyanin, allophycocyanin and
phycoerythrin. They work only in conjunction with
proteins.
Scitomin (not all) - absorbs in
ultraviolet part of the spectrum (212 - 300 nm).
13

14. Reproduction

Cell division.
With the help of gonidia (endospores - if inside
maternal cell, exospores (baeocytes) - if
outside).
Filamentous - with the help of hormogonia. Usually decay goes
by heterocysts (heterocysts themselves are not capable of
reproduction!)
Akinetami - disputes.
There is no typical sexual reproduction. There is
parasexual processes in which there is an exchange
genomes in different cells.
14

15. Order Chroococcal (Chroococcales)

15

16.

16

17.

17

18. Order pleurocapsales (Pleurocapsales)

18

19. Order Oscillaroriales

19

20. Nostocales order

20

21. Nostoc paludosum

21

22. Nodularia spumigena

22

23.

23

24. Order of Stigonematales

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25. The value of blue-green algae in nature and in human life:

The appearance of oxygen and the ozone layer.
Played a role in the creation of rocks and
soil formation.
They are components of the lichen thallus.
Primary producers.
"Blooming water".
Grown as a source of obtaining

They are used as test objects.
Application for fertilizer farmland as
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nitrogen source.

26. Habitats of blue-green algae

Fresh water
Seas
Soil, rocks
Symbionts of some flagellates,
rhizomes, etc.
26

27.

Flowering microcystis
Cyanobacterial mat (synechocystis)
Sectional Cyanobacterial Mat
27

28. EVGLENE ALGAE - EUGLENOPHYTA

Pigments:
Chlorophylls "a" and "b"
carotenoids
Spare substance:
paramilon
Many euglena chloroplasts
No
About 1000 species.
Most are monadic, there are also coccoid and
amoeboid.

29.

The body is covered with pellicle - elastic protein
the protoplast layer under the plasmolemma - this allows
crawl

30.the structure of the euglena cell

31. Euglena

32. Phacus

33. Trachelomonas

34. THE IMPORTANCE OF EVGLENE ALGAE

Participate in the process of self-purification of water
Water pollution indicators
Objects for studying photosynthesis, structure
chromatophores, phototaxis, flagella movements
They investigate the effect of antibiotics, herbicides,
growth substances
They are used to quantify
vitamin B12

35. Green algae (Chlorophyta)

35

36. Types of organization of green algae thallus

Monadic
Palmeloid
Cocoid
Filamentous
Multi-filamentous (heterotrichal)
Parenchymal
Pseudoparenchymal
Siphon. Mostly green, some yellow-green
Harophytic.
Siphon storage. Only in the green
Sarcinoid.
!!! The rhizopoidal organization of the thallus in green algae is not
found !!!
36

37. Structural features

The cell membrane is rigid, most often cellulosic. It also happens
peptidoglycan; sproropellin (degradation product
carotenoids, in higher plants - is part of the shell
pollen).
A spare product - starch, is deposited inside the chloroplast (around
pyrenoid and in the stroma). However, not all. The Dazikladovs have inulin. Have
some (for example, representatives of the genus Dunaliella - lipids).
Chloroplast is usually one. Located in the center of the cell. But there is
exceptions both in quantity and location of chloroplasts in
cage. Chloroplasts are green.
The stigma (light-sensitive eye) is located inside the chloroplast and is not
associated with the flagellar apparatus.
Most species have a large intracellular vacuole with
cell juice.
Mobile species have flagella, their number varies.
37

38. Photosynthetic pigments

Chlorophyll a
Chlorophyll b
Carotenoids (alpha and beta carotene,
lutein, neoxanthin, zeaxanthin and others)
38

39. Reproduction

Asexual (cell division in two,
motionless aplanospores,
mobile zoospores).
Vegetative (breaking the filaments).
Sexual (isogamy, heterogamy, oogamy -
most often conjugation).
Life cycles: zygotic reduction,
spore reduction (with heteromorphic
change of generations).
39

40. What is the difference between the subdivisions of Chlorophyta?

Features of the flagellar apparatus.
Features of mitosis.
Features of cytokinesis.
Metabolic peculiarities.
40

41.

41

42. Subdivision Chlorophytina

Prasinophyceae class
The class of actually green algae
(Chlorophyceae)
Class trebuxiaceae (Trebouxiphyceae)
Ulvovye class (Ulvophyceae)
42

43. Prasinophyceae class

Free-living inhabitants of the seas and
freshwater bodies
Tetraselmis sp.
The class includes forms: monadic,
less often palmeloid and coccoid
shape
43

44. Class actually green algae (Chlorophyceae)

Types of thallus organization: monadic,
palmeloid, coccoid, filamentous,
heterotrichial.
During mitosis, the telophase body is not preserved, the threads
spindles in anaphase are always shortened.
Cell division always occurs with a groove
or the formation of a plate with the participation
phycoplast (microtubule plates). Because of
the presence of such a structure is assumed that
this class is a dead-end branch of evolution.
Life cycles are haploid with zygotic
44
reduction.

45. Volvocales order

Unicellular, colonial and coenobial monad forms.
Under unfavorable conditions - palmeloid state.
45
Reproduction: vegetative, asexual, sexual - isogamy (less often hetero- and oogam

46.

Dunaliella salina
46

47.

Haematococcus pluvialis
Chlamydomonas reinhardtii
47

48. Chlorococcal order (Chlorococcales)

Coccoid forms as unicellular,
and colonial.
Chloroccocum acidum
Asexual reproduction - flagellate
zoospores and autospores. Sexual process
isogamous, oogamous and heterogamous.
Hydrodictyon sp.
48

49.

Scenedesmus quadricauda
Pediastrum
49

50. Order oedogoniales

Filamentous type of thallus organization.
The filaments are more often branching.
Asexual reproduction -
zoospores. The sexual process is oogamous.
50

51. Order of Chaetophorales

Multiple thalli
Fritschiella tuberosa
Iso-, hetero- and oogamy
51

52.

52

53. Class trebuxiae (Trebouxiphyceae)

Eremosphaera viridis
Coccoid, filamentous and lamellar.
Asexual reproduction - autospores, cell division
... The sexual process is oogamous.
Prasiola stiputata
53

54. Class Ulvophyceae Order Ulothricales

.
Ulvovye class (Ulvophyceae)
Order of ulotrix
(Ulothricales)
Thallus are coccoid, filamentous, lamellar.
Asexual reproduction is autospores, the sexual process is isogamous.
54

55. The order of the Ulvales

Thallus lamellar or tubular
Asexual reproduction - by zoospores, vegetative - by sections of the thallus.
The sexual process is isogamous and heterogamous.
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56. Order bryopsidales

Caulerpa
Bryopsis
Tall siphon.
No radial symmetry.
Asexual reproduction is almost nonexistent.
The sexual process is heterogamous, less often isogamous.
Codium
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57. Order of the Dasicladales

The sexual process is isogamous.
Tall siphon.
Radially symmetrical.
57

58. Siphonocladales order

Thallus siphon-fold
Cladophora
Asexual reproduction - zoospores
The sexual process is heterogamous.
58

59. Subdivision Charophytina

Class Trentepohliophyceae
Klebsormidia class (Klebsormidiophyceae)
Conjugate or Coupling class
(Zygnematophyceae, Conjugatophyceae)
Class charovy (Charophyceae)
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60. Class Trentepohliophyceae

Thallus heterotrichal, but reduced
Asexual reproduction is by zoospores.
Vegetative is the main one.
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61. Class Klebsormidia (Klebsormidiophyceae) Order Klebsormidia

Cocoid, sarcinoid and filamentous thalli.
Asexual reproduction is zoospores.
Vegetative.
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62. Coleochaetales order

Filamentous thallus.
Asexual reproduction - zoospores
The sexual process is oogamous.
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63. Class of conjugates or couplers (Zygnematophyceae, Conjugatophyceae) Order Zygnematales

Unicellular and filamentous forms.
Vegetative.
The sexual process is conjugation.
63

64. Order Desmidiales

Vegetative.
Unicellular and filamentous forms.
Cosmarium
The sexual process is conjugation.
Straurastum
64

65. Class charovy (Charophyceae)

The thallus is heterotrichous, complicated.
Vegetative with the help of nodules, the sexual process is complicated.
65

66. The value of green algae in nature and human life

Primary producers. The basis of food
chains.
Oxygen producers.
Test objects.
Grown to receive
biologically active substances.
Serve as food for humans and
farm animals.
66

67. Habitats

Seas
Fresh water
On trees, buildings.
The soil

The sub-kingdom of oxyphotobacteria - Oxyphotobacteria, or Oxyphotobacteriobionta - are autotrophic prokaryotes capable of aerobic photosynthesis. These include cyanobacteria and chloroxybacteria. The type of autotrophic prokaryotic organisms is "more bacteria than algae." Solitary and colonial forms. The colonies are created by organogenic limestone structures (stromatolites).

Cyanobacteria are surprisingly unpretentious microorganisms that only need sunlight, water and air. Their role in the evolution and existence of the biosphere of our planet is especially significant [Gromov B.V. 2000]. By the nature of their cellular organization, they correspond to gram-negative bacteria and represent their independent evolutionary branch. In the botanical literature, cyanobacteria are still sometimes called blue-green algae, where they are considered a high-rank taxon - a division or type in the system of lower plants. Blue-green - the most ancient organisms of the Earth (Archaea - now). Known from deposits of at least 2.8 billion years old, they still play an important role in the cycles of matter and energy.

In their cells there is not only a nucleus, but also chromatophores - cellular formations containing pigments and taking part in photosynthesis, there are no vacuoles. In the central dense part of blue-green cells, nucleoproteins are concentrated - compounds of nucleic acids with a protein. Blue-greens are remarkable in that they are able to use atmospheric nitrogen and convert it into organic forms of nitrogen. In photosynthesis, they can use carbon dioxide as their only source of carbon. In contrast to photosynthetic bacteria, blue-greens release molecular oxygen during photosynthesis.

Cyanobacteria living among plankton have gas vesicles that contain gas and give their cells a better buoyancy. Some cyanobacteria are capable of cell differentiation. One of the types of specialized cells are akinets (or spores) - these are large resting cells with a thickened membrane. They serve for the survival of the organism in adverse conditions. When optimal conditions are reached, akinets germinate. Another type of differentiated cells are heterocysts - specialized cells in which the process of fixing atmospheric nitrogen is carried out. They can be formed by some filamentous cyanobacteria (Anabaena, Nostoc).

It was already mentioned above that blue-green ones are represented not only by unicellular, but also by colonial, filamentous and multicellular forms. But multicellular nuclear organisms evolved not from multicellular blue-green, but from unicellular nuclear forms. Thus, for the first time in blue-greens, an attempt is made to break through to the next stage - to the level of multicellularity. However, this attempt had little evolutionary implications.

Cyanobacteria are the only example of a prokaryotic multicellular organism in which functional cell specialization occurs.

Understanding the potential of cyanobacteria is expanding with the availability of developed genetic methods and data on genomic nucleotide sequences. Cyanobacteria are intensively used as model organisms for the study of fundamental biological processes, including: photosynthesis and its genetic control [

Taxonomy
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Evolutionary and systematic position

Cyanobacteria are closest to the most ancient microorganisms, the remains of which (more than 3.5 billion years old) have been found on Earth. These are the only bacteria capable of. Cyanobacteria are among the most complex and morphologically differentiated prokaryotic microorganisms. The ancestors of cyanobacteria are considered in theory as the most likely ancestors. The non-systematic grouping under the conditional name "prochlorophytes" according to this theory has common ancestors with other algae and higher plants.

Cyanobacteria are the object of research both (as organisms that are physiologically similar to algae) and (as). The relatively large size of the cells and the similarity with algae were the reason for their consideration earlier in the composition ("blue-green algae"). During this time, more than 1000 species in almost 175 genera have been described algologically. The existence of no more than 400 species has now been confirmed by bacteriological methods. , and the similarity of cyanobacteria to the rest of the bacteria is now supported by a solid body of evidence.

Life forms and ecology

Blue-green algae, dried on the banks of the Kiev reservoir

Morphologically, cyanoprokaryotes are a diverse and polymorphic group. The common features of their morphology are only in the absence of flagella and the presence of a cell wall (consisting of). On top of the peptidoglycan layer 2-200 nm thick, they have an outer membrane. The width or diameter of the cells varies from 0.5 µm to 100 µm. Cyanobacteria - and microorganisms. They are distinguished by an outstanding ability to adapt the composition to the spectral composition of light, so that the color varies from light green to dark blue. Some cyanobacteria are capable of - the formation of specialized cells: and. Heterocysts perform a function while other cells perform photosynthesis.

Most cyanobacteria are obligate, which, however, are capable of short-lived existence due to the splitting of the accumulated in the light in and during the process (the sufficiency of one glycolysis to maintain vital activity is questioned).

Meaning

Cyanobacteria, according to the generally accepted version, were the "creators" of the modern oxygen-containing atmosphere on Earth, which led to "" - a global change in the composition of the Earth's atmosphere, which occurred at the very beginning of the Proterozoic (about 2.4 billion years ago), which led to the subsequent restructuring of the biosphere and global ...

At present, being a significant component of oceanic plankton, cyanobacteria are at the beginning of the greater part and produce a significant part (the contribution is not precisely determined: the most probable estimates range from 20% to 40%).

Cyanobacteria became the first photosynthetic organism, whose was completely deciphered.

Currently, cyanobacteria are the most important research in biology. In both the bacteria of the genus and due to the lack of other types of food, they are used for food: they are dried, and then flour is prepared. The possible application of cyanobacteria in the creation of closed life support cycles is considered.

Classification

Historically, there have been several systems for classifying the highest levels of cyanobacteria.

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Cyanobacteria

Blue-green algae, cyanobacteria (Latin Cyanobacteria, from the Greek κυανός - blue-green) are a significant group of large gram-negative eubacteria capable of photosynthesis, accompanied by the release of oxygen.

Evolutionary position and taxonomy

Cyanobacteria are closest to the most ancient microorganisms, the remains of which (stromatolites, more than 3.5 billion years old) have been found on Earth. The only bacteria, along with prochlorophytes, capable of oxygenic photosynthesis, the ancestors of cyanobacteria are considered in the theory of endosymbiogenesis as the most probable ancestors of chromatophores of red algae (according to this theory, prochlorophytes have common ancestors with chloroplasts of other algae and higher plants).

The relatively large size of cells and physiological similarity with algae was the reason for their consideration earlier in the composition of algae ("blue-green algae", "cyanea"). During this time, more than 1000 species in almost 175 genera have been described algologically. Bacteriological methods have now confirmed the existence of no more than 400 strains. The biochemical, molecular genetic and phylogenetic similarity of cyanobacteria with other bacteria is currently confirmed by a solid body of evidence, but still some botanists, paying tribute to tradition, tend to attribute cyanobacteria to algae.

Life forms and ecology

Cyanobacteria are unicellular, filamentous and colonial microorganisms. The average cell size is 2 µm. They are distinguished by an outstanding ability to adapt the composition of photosynthetic pigments to the spectral composition of light, so that the color varies from light green to dark blue. Some higher nitrogen-fixing cyanobacteria (Nostocales) are capable of differentiation - the formation of specialized cells: heterocysts and hormogonia.

Marine and freshwater, soil species, participants in symbiosis (for example, in a lichen). They make up a significant proportion of oceanic phytoplankton. Capable of forming thick bacterial mats. Some species are toxic (the most studied is the microcystin toxin produced, for example, by Microcystis aeruginosa) and opportunistic (Anabaena sp.). The main participants in water bloom cause massive fish deaths and poisoning of animals and people, for example, when water blooms in reservoirs of Ukraine. The unique ecological position is due to the combination of two difficult-to-combine abilities: to photosynthetic production of oxygen and fixation of atmospheric nitrogen (in 2/3 of the studied species).

Division is binary in one or more planes, multiple division. The life cycle in unicellular forms under optimal growth conditions is 6-12 hours.

Biochemical features and physiology

Cyanobacteria have a full-fledged photosynthetic apparatus characteristic of oxygen-releasing photosynthetics. The photosynthetic electron transport chain includes photosystem (PS) II, b6f-cytochrome complex, and PSI. The final electron acceptor is ferredoxin, the electron donor is water, which is split in the water oxidation system, similar to that of higher plants. Light-collecting complexes are represented by special pigments - phycobilins, collected (as in red algae) in phycobilisomes. When switched off, PSIIs are capable of using exogenous electron donors other than water: reduced sulfur compounds, organic compounds in the framework of cyclic electron transfer with the participation of PSI. However, the efficiency of this pathway of photosynthesis is low, and it is used mainly for experiencing adverse conditions.

Cyanobacteria are distinguished by an extremely developed system of intracellular invaginations of the cytoplasmic membrane (CPM) —thyldakoids; suggestions were made about the possible existence of a thylakoid system in them that is not associated with the CPM, which was considered impossible in prokaryotes until now. The energy stored in photosynthesis is used in the dark processes of photosynthesis to produce organic matter from atmospheric CO2.

Most cyanobacteria are obligate phototrophs, which, however, are capable of short-term existence due to the cleavage of glycogen accumulated in the light in the oxidative pentose-phosphate cycle and in the process of glycolysis (the sufficiency of one glycolysis to maintain vital activity is questioned). The tricarboxylic acid (TCA) cycle cannot participate in energy production due to the absence of α-ketoglutarate dehydrogenase. The “disruption” of the TCA, in particular, leads to the fact that cyanobacteria are distinguished by an increased level of metabolite export to the environment.

Nitrogen fixation is provided by the enzyme nitrogenase, which is highly sensitive to molecular oxygen. Since oxygen is released during photosynthesis, two strategies have been implemented in the evolution of cyanobacteria: spatial and temporal separation of these processes. In unicellular cyanobacteria, the peak of photosynthetic activity is observed in light, and the peak of nitrogenase activity is observed in the dark. The process is regulated genetically at the level of transcription; cyanobacteria are the only prokaryotes in which the existence of circadian rhythms has been proven (and the duration of the diurnal cycle may exceed the duration of the life cycle!). In filamentous cyanobacteria, the process of nitrogen fixation is localized in specialized terminally differentiated cells - heterocysts, characterized by thick integuments that prevent oxygen penetration. With a lack of bound nitrogen in the nutrient medium, the colony contains 5-15% of heterocysts. PSII is reduced in heterocysts. Heterocysts receive organic matter from photosynthetic members of the colony. The accumulated bound nitrogen is accumulated in cyanophycin granules or exported as glutamic acid.

Taxonomy
The taxonomy of cyanobacteria has not been sufficiently developed. There are five orders: the orders Chroococcales and Pleurocapsales combine single or colonial relatively simple forms; the orders Oscillatoriales, Nostocales, Stigoneomatales include filamentous highly organized forms.

Significance Cyanobacteria, according to the generally accepted version, were the "creators" of the modern oxygen-containing atmosphere on Earth (according to another theory, atmospheric oxygen is of geological origin), which led to the first global ecological catastrophe in natural history and a dramatic change in the biosphere. Currently, as a significant component of oceanic plankton, cyanobacteria are at the beginning of most of the food webs and produce most of the oxygen (the contribution is not recognized by all researchers). Cyanobacterium Synechocystis became the first photosynthetic organism, whose genome was completely deciphered. At present, cyanobacteria are the most important model objects for research in biology. In South America and China, bacteria of the genus Spirulina and Nostoc, due to the lack of other types of food, are used for food, drying and cooking flour. They are credited with healing and healing properties, which, however, have not yet been confirmed. The possible application of cyanobacteria in the creation of closed life support cycles, as well as as a mass feed or food additive, is considered.

Department Gracilicutes

Class Oxyphotobacteria

OrderCyanobacteriales

Single-celled, colonial, filamentous organisms that live in water and on land in damp places (Fig. 16) . Contains bluish green pigment Phycocyanin and in connection with the habitat they used to be called Blue-green algae . However, cytologically, cyanobacteria are typical prokaryotes. Covered with mucus, capable of sliding motion. Sometimes a group of cells is united by a common mucous capsule and is called Zooglea. The cell wall is layered, contains a certain amount of peptidoglycan murein, gram-negative. There is a nucleoid Chromatophores (lamellar type mesosome system) carrying photopigments: Chlorophyll, phycocyanin, allophycocyanin causing a blue-green color. They feed photoautotrophically using photosynthesis. Cyanobacteria reproduce by binary fission, fragmentation of filaments, hormogonies - short mobile chains of cells. When passing through the life cycle, specialized cells or threads are formed: Hormogonia (serve for reproduction), heterocysts - Thick-walled cells capable of assimilating nitrogen from the air and akinets (resting stage for experiencing adverse conditions) . Oscillator does not form heterocysts and is capable of assimilating atmospheric nitrogen only under anaerobic conditions. In the presence of oxygen in the medium, nitrogen fixation stops. Have Anabens there are heterocysts that protect the nitrogen fixation system from oxidation, so it assimilates nitrogen and carbon dioxide from the air in the light at the same time. Cyanobacteria are highly resistant to antibiotics and ultraviolet rays.

The value of cyanobacteria:

1). They are the primary producers of organic matter in water and soil.

2). Saturate water and atmosphere with oxygen.

3). Participate in soil formation, in fixing atmospheric nitrogen.

4) .Used as an environmentally friendly fertilizer in rice fields (anabena).

5). They form a lot of protein and biologically active substances (vitamins), therefore they are used for the manufacture of medicines (spirulina).

6) .Causes the bloom of reservoirs, produce strong neurotoxic poisons, as a result of which the water becomes undrinkable.

Rice. 16 . Cyanobacterial morphology: 1) Gloeocapsa ; 2) Nostoc ; 3) Anabaena ; 4) Oscillatoria , 5) Lyngbya ; SpecializedCells: A) hormogonia; b) heterocysts