Distinctive characteristics of the major groups of microorganism

Differentiative habits of the main groups of microbial

Some of the collection of organisms, microbes can be grouped in main r groups based on certain characters . Just as the different cat or insect species resemble each other in some or many ways, microorganisms harbor features with others of their types . The major types of microorganisms are protozoa, fungi, algae, and bacteria. Viruses, while not considered to be as having life , have some characteristics of living cells; they also have the tendency to create of diseases of humans, animals, and plants, and are studied very much like microorganisms. Although these types are described in detail in below, the following discussion reveals their major features:

Protozoa

Protozoa are single-celled, eukaryotic microorganisms. They are animal-like in that they usually ingest particulate of food, absence a rigid cell wall, and do not possess chlorophyll. Some of them usually swim through water by the beating action of short, hairlike appendages called cilia, or long, whiplike appendages called flagella. It is their rapid, darting movement in a specimen of pond water that harbor your attention when you look at them through the microscopic devices.

Other protozoa, called amoebas, do not swim, but usually, creep along surfaces by extending a part of the cell (a pseudopod) and then allowing the rest of the cell to flow into their extension. The type of locomotion is called amoeboid movement. The another type of protozoa are called sporozoans because they form resting bodies called spores during one phase of their life-cycle; they are usually not motile in this forms.

Protozoa are found widely in nature, particularly in aquatic environments. Some cause animal and human disease, such as coccidiosis in chickens and malaria in humans. Some protozoa are profit for humans , such as those found in the stomachs of cattle, sheep, and termites that help digest food.

Algae

Algae are considered like vegetation because they contain the green pigment chlorophyll, involve in photosynthesis, and have rigid cell walls. These eukaryotes are usually unicellular and microscopic in size, or multicellular and up to many meters in length. Species of algae have a wide range of sizes and shapes. These organisms develop in many different environments, although most are aquatic and a food source for aquatic animals. They can cause problems by clogging water pipes, releasing toxic chemicals into bodies of water, or growing in swimming pools. But extracts from specific algal species also have essential commercial uses: as thickeners and emulsifiers for foods such as ice cream and custards; as anti-inflammatory drugs for ulcer treatment; and as a source of agar, which is important to solidify nutrient solutions on which microbes are grown.

Fungi

Fungi are eukaryotic organisms which, like algae, have rigid cell walls and may be either unicellular or multicellular. Some of them may be microscopic in size, while others are much huge , such as the mushrooms and bracket fungi growing on damp logs or soil. Unlike algae, fungi do not contain chlorophyll and thus cannot usually carry out photosynthesis. Fungi do not eat food, but must absorb dissolved nutrients from the environment. Of the fungi that are classified as microorganisms, those that are multicellular and produce filamentous, microscopic structures are frequently called molds, usually, yeasts are unicellular fungi.

In molds, cells are cylindrical in shape and are attached end to end to form threadlike filaments called hyphae that may bear spores. Individually, hyphae are microscopic in size. However, when large numbers of hyphae accumulate on a slice of bread, for example, the moldy mass called the mycelium is visible to the naked eye. Molds have considerable value; they are used to produce the antibiotic penicillin, soy sauce, Roquefort and camembert cheeses, and many other products. But they also are responsible for the deterioration of materials such as textiles and wood, and the unsightly growth in your shower or bath. They cause diseases of humans, animals, and plants, including athlete’s foot and the moldy spoilage of peanuts.

The unicellular yeasts have much shapes-spherical to ovoid, ellipsoidal to filamentous. Like the molds, yeasts are both useful and detrimental. They are widely used in the banking industry, where they produce gas that makes the dough rise. Because of their ability to produce alcohols, yeasts are essential for the production of all alcoholic beverages. On the other hand, they cause food spoilage and diseases such as vaginitis and thrush (an oral infection).

Bacteria

Unlike the previously described microorganisms, bacteria are prokaryotes, the absence of the nuclear membrane and other organized intracellular structures seen in eukaryotes. On the basis of things discussed earlier, bacteria are divided into two major groups, the eubacteria, and the archaeobacteria.

Eubacteria have a variety of shapes, especially spheres, rods, and spirals. They are different in that the individual cells range in width from 0.5 to 5.0 micrometers. Although unicellular, eubacteria often appear in pairs, chains, tetrads (groups of four), or clusters. Those with flagella can swim rapidly through liquids. Of great importance both in nature and in industry, eubacteria are essential in recycling wastes and in the production of antibiotics such as streptomycin. Infections caused by eubacteria include a streptococcal sore throat, tetanus, plague, cholera, and tuberculosis.

Through a microscopic, the archaeobacteria look same as eubacteria. But there are important differences in their chemical composition and activities, and in the environments in which they multiply . Many archaeobacteria are noted for their ability to survive unusually harsh surrounding, such as those with high levels salts or acid, or high temperatures. Their habitat in salt flats and thermal pools, for example. Some are capable of a unique chemical activity- the production of methane gas from carbon dioxide and hydrogen. Methane-producing archaeobacteria live only in environments with no oxygen, such as deep in swamp mud, or in the intestines of ruminants such as cattle and sheep.

Viruses

Structures so-called viruses represent the borderline between living and non-living things. They are not cells, different from the microbes discussed thus far. They are much minute (20 to300 nanometers, or n, in diameter) and much simpler in structure than bacteria, yet they can insert themselves into the genetic material of cells and do great devastating problems , AIDS is caused by the human immunodeficiency virus (HIV). The common cold, genital herpes, poliomyelitis, and hepatitis are the viral disease, as are tobacco mosaic (a disease of the tobacco plant) and foot-and-mouth disease of animals. Viruses have been implicated in the growth of some malignant tumors.

Unlike cells, viruses contain only one type of nucleic acid, either acid, either RNA or DNA, which is in around by a protein envelope, or coat. Because they lack the cellular components necessary for metabolism or independent reproduction, viruses can multiply only within living cells. After invading a plant or animal cell, or a microorganism, a virus has the ability to force the host cell’s genetic machinery to make many copies of the virus. Despite their simple structure, viruses exist in several shapes.

References

Arvind, Keshari K. and Kamal K Adhikari. A Textbook of Biology. Vidyarthi Pustak Bhander.

Michael J.Pleczar JR, Chan E.C.S. and Noel R. Krieg. Microbiology. Tata Mc GrawHill, 1993.

Powar. and Daginawala. General Microbiology.

Rangaswami and Bagyaraj D.J. Agricultural Microbiology.