Cyanobacteria: Definition, Characteristics, Role, Reproduction, Classification, & Examples

sinaumedia Literacy – Blue green algae (cyanobacteria) and their places of life that we often encounter in everyday life, such as in lakes, rivers, seas, swamps, rocks, soil.

For more details, Edutore will discuss the types of blue-green algae, and their role in human life, here’s Sinaumed’s. Check these out!

DEFINITION OF CYANOBACTERIA

Algae or Blue Green Algae (Cynobacteria) is a group of Eubacteria (bacteria). Members of Cyanobacteria are scattered in various places, for example in waters, soil, rocks and boulders. In general, blue green algae are abundant in waters that have a neutral pH or waters that are slightly alkaline. Very rarely found in waters with a pH of less than 4-5.

In addition, there are also Cyanobacteria which are capable of symbiosis with other organisms, such as Gloeocapsa and Nostoc which form symbiosis with algae that form liche, Anabaena symbiosis with liverworts, water ferns and palms to fix nitrogen. Cynobacteria contain a type of chlorophyll, and various carotenoids as well as phycocyanin and phycoerythrin. In the presence of phycocyanin, then Cyanobacteria has a distinctive color, namely bluish green. Cynobacteria act as pioneer plants that form bare soil surfaces and also play an important role in adding organic matter to the soil.

Not all of the bacteria in the world can be harmful to humans or animals. But there are also bacteria that can help human survival. The book Everything About Bacteria and Viruses that is below will explain the various types of bacteria that exist in the environment.

CHARACTERISTICS OF CYANOBACTERIA

Here are some characteristics of cyanobacteria that you need to know, Sinaumed’s!

1. Cyanobacteria body size ranges from 1 mm – 60 mm
2. Has a cell wall containing a thin peptidoglycan layer.
3. Can carry out photosynthesis
4. Has phycobilin pigment
5. Can be found in moist soil or clean water
6. Has a prokaryotic cell structure

BODY SHAPE AND SIZE OF CYANOBACTERIA

In contrast to bacteria in general which are unicellular (single cell), Cyanobacteria’s body shape is multicellular and some are unicellular. Cyanobacteria bodies are multicellular in the form of filaments (threads), for example Oscillatoria, Microcoleus, Rivularia, Plectonema boryanum, and Anabaena.

There are unicellular cyanobacteria that are solitary (alone) and some are in colonies. Cyanobacteria with solitary spherical shape, for example Chroococcus and Anacystis, while Cyanobacteria with colonial spherical form, for example Merismopedia, Nostoc, Gloeocapsa, and Mycrocystis.

Cyanobacteria’s body size ranges from 1 mm – 60 mm, making it easy to observe with an ordinary light microscope. Oscillatoria princeps is a thread-shaped cyanobacteria with the largest body size. Thread-shaped cyanobacteria are also called trichomes, consisting of cells arranged like a chain. In trichomes there are several cells with different shapes and functions, as follows:

  • Heterocyst, is a cell that is larger than other body cells, thick-walled, with clear contents and contains the enzyme nitrogenase. Heterocysts function to fix nitrogen.
  • Akinet, are cells that are larger than other body cells, function to store food reserves, have thick walls, and contain endospores. These cells function to defend themselves in bad environmental conditions.
  • Baeocytes, are vegetative cells which are the result of reproduction (cell division), are round in shape, small in size, and have chlorophyll. These cells function for photosynthesis.

CYANOBACTERIA CELL STRUCTURE

The structure of the cells that make up the body of Cyanobacteria is similar to that of Gram-negative bacterial cells, with the main characteristic of having a cell wall containing a thin peptidoglycan layer. Cyanobacteria cells consist of several parts, namely the mucus layer, cell wall, plasma membrane, photosynthetic membrane, mesosomes, cytoplasm, ribosomes, storage granules, gas vacuoles, solid proteins, and nucleoplasm (DNA).

  • Mucus layer, covering the cell wall. Mucus functions to help gliding movement (locomotion) in unicellular Cyanobacteria, as well as vibrating or back and forth (oscillation) motion in Cyanobacteria in the form of threads (filaments). Take the Oscillatoria for example
  • The cell wall contains a thin layer of peptidoglycan and functions to provide a fixed shape to the algae and protect the contents of the cell.
  • The cell membrane (plasma membrane), is selectively permeable and functions to wrap the cytoplasm and regulate the exchange of substances.
  • The photosynthetic membrane (thylakoid membrane), is a folding of the plasma membrane towards the inside of the cytoplasm which functions for photosynthesis. The photosynthetic membrane contains chlorophyll (green), carotene, and other photosynthetic pigments, including phycoerythrin (red) and phycocyanin (blue). The combination of these pigments causes Cyanobacteria to have different colors, including yellowish, reddish, brown, violet, bright green, bluish green, even black.
  • Mesosomes, are protrusions of the membrane into the cytoplasm and function to produce energy.
  • Cytoplasm, is a colloidal solution composed of water, protein, fat, sugar, minerals, and enzymes. Within the cytoplasm are ribosomes, storage granules, gas vacuoles, solid proteins, and nucleoplasm (DNA).
  • Ribosomes are small organelles that function for protein synthesis.
  • Storage granules, function to store food reserves.
  • Gas vacuoles, filled with air that causes Cyanobacteria bodies to float on the surface of the water, so they get sunlight to photosynthesize.
  • Nucleoid, is the genetic material composed of DNA and not surrounded by a membrane. The nucleoid is located at a specific location.
See also  Xylem

CYANOBACTERIA HABITAT

Cyanophyta can be found in various environments such as lakes, seas and rivers. Cyanophyta can be seen with the naked eye in the form of a thin layer of green, blue, red or purple-black. At certain times, Cyanophyta that live in water appear abundant, causing the water to appear colored like the color of the Cyanophyta. For example, the blue-green Cyanophyta (Anabaena) makes the rice fields look green and the red Cyanophyta (Ascillatoria rubescens) makes the sea in the Middle East region red, so it is called the Red Sea.

Several types of Cyanophyta which can fix nitrogen act as pioneer plants in nutrient-poor (food) habitats, such as beaches. Cyanophyta, Synecococcus lividus can live in extreme habitats, for example habitats with high acidity (pH 4.0) and high temperatures. While there are other types that live in symbiosis with other organisms, for example Nostoc and Anabaena azollae.

CYANOBACTERIA REPRODUCTIVE SYSTEM

We often encounter blue algae in lakes, rivers, seas, swamps, rocks, soil, in water with high temperatures, or in water with high acidity (pH = 4). Following are some of the reproductive systems in cyanobacteria, including:

  • Binary Fission: Binary fission can occur in unicellular or multicellular Cyanobacteria in the form of filaments (threads). In unicellular Cyanobacteria, some of the cells resulting from division separate immediately, and some are still joined together to form colonies (eg Gloeocapsa). Cells resulting from division in Cyanobacteria in the form of filaments cause the filaments to increase in length.
  • Fragmentation: Fragmentation is the breaking of a part of the body of an organism. The body part that is released will grow into a new individual. Fragmentation occurs in Cyanobacteria which are in the form of filaments. Termination of body parts can occur in certain parts of the dead cells. The resulting filaments are called hormogonia. These hormogonia have different filament lengths, and if they are released from the main filament, they will grow into new Cyanobacteria. Examples of Cyanobacteria that experienced fragmentation include Oscillatoria sp. and Plectonema boryanum.
  • Formation of Endospores: Formation of endospores occurs when environmental conditions are unfavorable, for example in drought conditions. The cells that contain these endospores are called akinet. Akinet comes from vegetative cells, which are larger than other body cells because they contain food reserves, and have thick walls. When environmental conditions improve, the endospores will grow into new Cyanobacteria, for example Nostoc sp.

CLASSIFICATION OF CYANOBACTERIA

Cyanobacteria belongs to the kingdom Monera, the cyanophyta division Cyanophyceae is divided into 3 orders based on whether or not it can form spores, namely: the order Chroococcales, Chamaesiphonales, and Hormogonales.

ORDER CHOOCOCCALES

This order is single or in groups without spores, with a greenish-blue color. Generally, this algae forms a mucous membrane on wet rock or walls. After the process of division, the cells remained attached to each other by means of mucus so that groups or colonies were formed, examples of species from the order Chroococcales, including Chrococcus, Gleocapsa, Anacystis, Merismopedia, Eucasis, Coelosphaerium, and Mycrocystis.

ORDER CHAMAESIPHONALES

Algae are single-celled or are thread-shaped colonies that have spores. These threads are hormogonium which can creep and form new colonies. Spores themselves are formed from the contents of the cell (endospores), after leaving the parent cell the spore can become a new plant. The order Chamaesiphonales is divided into 3 families:

  • Dermocarpaceae family: Division of the vegetative cell into 2 equal cell parts is possible in members of this family. Examples of species include: Dermocarpa. The cells are round to slender or pyriform and grow attached to the substrate in clusters. Reproduction is accomplished independently by endospores which may develop in large numbers with vegetative cells
  • Family Chamoesiphonaceae, Examples of this species are: Chamaesiphon. It has a wide distribution and is generally epiphytic. Occurring in aquatic angiosperm plants, mosses and algae especially Chladophora and in mature plants, the protoplast at the distal pole forms a chain of spores called exospores.
  • Pleurocapcaceae family:
    • Xenococcus: The spherical cells of Xenococcus attach to the algal filaments, they undergo anticlinal division to increase the size of the colony. Each cell can produce many endospores and are called baeocyts which differentiate them from bacterial spores. The endospores of some blue-green algae may be motile for brief periods.
    • Hyella: The trichome branch of Hyella grows from desmoschsis which lives in calcareous shells or with other algae. The large filaments may become pluricular. Many cells may divide to form endospores.

ORDER HORMOGONALES

The cells are colonies in the form of threads or covered with a membrane. The threads are attached to the substrate, do not branch, and rarely have true branches, or more often have pseudo branches. These threads can always form hormogonium. The Hormogonales order itself is divided into 5 families, namely:

  • Family Oscillatoriaceae: Live in water or on wet soil, the cells are round, are threads and eventually form a slimy colony. Examples of the species are:
  • Oscillatoria: The trichomes of Oscillatoria are cylindrical and unbranched. They only have one membrane. Trichomes are often found in buoy masses or shiny parts of moist soil.
  • Spirullina: This algae contains high levels of protein so that it is used as a food source. Spirulina is able to produce carbohydrates and other organic compounds that are needed by the body, and also produce high enough protein.
  • Mycrocaleus: Trichomes are sometimes rolled over one another, and are on the same membrane. Several species of Mycrocaleus live in fresh water, sea and also on moist sand.
  • Family Nostocaceae: Unbranched trichomes, heterocysts and akinetes are present in adult organisms. Examples of this species are Nostoc, Anabaena and Cylindrospermum.
  • Scytonemataceae family: Trichomes with membranes which may be colored. Trichomes are characterized by false branching without initiation of cell division in new planes, trichomes or hormogonia breaking off or growing to join the membrane. Examples of this species are: Tolipotrix Trichome diameter is uniform and accompanied by a narrow membrane.
  • Family Stigonemataceae: Trichomes of several genera are pluriseriates. The trichomes differ from other cyanophytes in that their branching is initiated by cell division in a new section. Examples of this species are Hapalosiphon, and Stigonema.
  • Family Rivullariaceae: With trichomes that taper from the base to the apex or from the middle to the 2 ends. Examples of this species are:
  • Calothrix: Lives in fresh water, sea water and coats rocks or attaches to algae and other aquatic plants
  • Rivularia: Rivularia does not have an akinet. Several species of Rivularia are sub-area and live on moist coral.
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ROLE OF CYANOBACTERIA

Cyanobacteria (Blue Algae) have chlorophyll so they can photosynthesize and produce oxygen. There are various types of blue algae, such as single-celled blue algae, colonial blue algae, and thread-shaped blue algae. Following are some of the benefits of cyanobacteria or cyanophyta, including:

  • Nostoc: Soaking rice fields during the rainy season causes Nostoc to thrive and fix N2 from the air so that it can help provide nitrogen used for rice growth.
  • Anabaena azollae : Living in symbiosis with Azolla pinata (water fern). These ferns can fix nitrogen (N2) in the air and convert it into ammonia (NH3) which is available to plants.
  • Spirullina: This algae contains high protein which is better known as single cell protein (PST) so that it is used as a food source.
  • Cyanobacteria are the main nitrogen fixers in nature, nitrogen itself is needed by plants so Cyanobacteria is beneficial for plants, for example, Nostoc Commune, Anabaena Cycadae and Anabaena azollae. Cyanobacteria also play a very important role in adding organic matter to the soil.
  • As pioneer vegetation, namely by forming a layer on the bare soil surface so that it is able to live in an unfavorable environment where other plants cannot live in that area.
  • Spiriluna is capable of producing moderately high carbohydrate compounds and other very high organic compounds needed by humans as a food source that contains lots of protein in it. Therefore spiriluna can be used for the development of food sources in the future because this spiriluna is in pill form.
  • Cyanobacteria, namely as a free nitrogen fixer, means that the role of Cyanobacteria is to bind the main nitrogen in nature, nitrogen itself is needed by plants so that cyanobacteria are beneficial for plants, for example: Nostoc Commune, Anabaena Cycadae and Anabaena azollae.
  • As pioneer vegetation, that is by forming a layer on the bare soil surface so that it can live in an unfavorable environment where other plants cannot live in that area.
  • Spiriluna is capable of producing moderately high carbohydrate compounds and other organic compounds needed by humans as a food source that contains lots of protein in it. Therefore Spiriluna can be used to develop food sources in the future because Spiriluna is in pill form.

NEGATIVE EFFECTS OF CYANOBACTERIA

  • Several species of Cyanobacteria produce neurotoxins (neurotoxins), usually these poisons attack the liver (hepatotoxins) and cells (cytotoxins), then form endotoxins which are very dangerous for animals and humans.
  • If there are too many Cyanobacteria attached to the walls of the building, over time the walls of the house will crack.
  • As a result of human activities, Cyanobacteria can live in environments that contain high levels of phosphate and nitrogen. These levels in an aquatic environment are often caused by industrial and agricultural waste pollution. This condition can lead to the growth of Cyanobacteria in abundance. This overflow can cover the surface of the waters so that the sun and oxygen needed by other organisms in the waters are reduced.

Thus the definition, characteristics, habitat, reproductive system, classification, role and negative impacts of Cyanobacteria, I hope this is useful, Sinaumed’s!