Eubacteria

eubacteria is a group of all bacterium species, its type, characters and examples

1. EUBACTERIA Mrs. Praveen Garg VITS College, Satna

2. INTRODUCTION Eubacteria , or “true” bacteria, are single-celled prokaryotic microorganisms. They have a range of characteristics and are found in various conditions throughout all parts of the world. All types of bacteria fall under this title, except for  archaebacteria . There are three domains of life: Archaea , Bacteria, and Eukarya . Various groups exist as parasites and are responsible for animal and plant diseases. Some are free-living with some being beneficial to man. 

3. Characteristics of Eubacteria Eubacteria , or microorganisms lacking a defined membrane nucleus. All are enclosed by a cellular wall, which is made up of peptidoglycans in a cross-linked chain pattern . Unlike eukaryotes, bacteria have cholesterol present in the membrane to enhance permeability properties of the membrane. Bacteria also have a plasma membrane  within the cell wall. Some bacteria may have a flagella, or a projection composed of protein filaments, that is used for movement. Other bacteria may have pili , which are small projections all over the outside of the cell, and are used for sticking to surfaces and transferring DNA. 

4. Cytoplasm is composed of mainly water (70 %), but has a gel-like consistency. Bacteria do not have membrane-bound organelles. Ribosomes , are made up of RNA and protein used for  protein synthesis. Free floating within the cytoplasm. Bacteria can asexually reproduce through binary fission or budding. Binary fission is when two equal progeny cells are produced.  During times of extreme conditions, such as starvation, eubacteria have the ability to become endospores . Plasmids are also found within bacteria separate from the bacteria’s circular DNA. Also referred to as “ replicons ”, plasmids are autonomous replicating DNA molecules.

5. Types of Eubacteria Eubacteria are typically classified into five different phylums : Chlamydias , Cyanobacteria (Blue-green algae), Gram-positive bacteria, Proteobacteria , Spirochetes.

6. Spirochetes Proteobacteria Cyanobacteria Gram positive bacteria

7. Chlamydias   Chlamydias is a group of organisms belonging to the family Chlamydiaceae . Chlamydias are obligate intracellular parasitic bacteria. Chlamydias species are grouped as gram-negative, their peptidoglycan is not easily detectable. They are immotile and are dimorphic in nature.   Chlamydias

8. Gram-positive Bacteria A majority of Eubacteria are Gram-positive. These group are capable of photosynthesis (photosynthetic Eubacteria ), a majority are chemoheterotrophs and thus obtain nutrients from their surroundings.  Being Gram-positive bacteria, these species retain the primary colour with stain. They contain a thick peptidoglycan layer compared to Gram-negative species. Gram-positive bacteria can be found in different types of aquatic and terrestrial environments. Various species (e.g.  Mycoplasmas  and  Actinomycetes ) have been shown to form endospores . Many species are parasitic and capable of causing diseases in animals. Actinomycetes produce beneficial compound as antibiotics. 

9. Cyanobacteria Also known as blue-green algae. Cyanobacteria is a class of Eubacteria consisting of photosynthetic microbes. Commonly referred to as photosynthetic prokaryotes. These prokaryotes are ubiquitous in nature and can be found in such environments as ponds, rivers, lakes, desert soil, and hot springs. In these environments, some species are free-living (capable of photosynthesis) or may form symbiotic relationships with fungi to form lichens. Cyanobacteria include a thick and gelatinous cell wall; gliding among motile species and diverse morphological characteristics

10. Proteobacteria Proteobacteria represent the largest and most diverse group among prokaryotes. It includes various parasitic bacteria as well a free living bacteria, involved in nitrogen fixation. It include Gram- negative, that can not be stain with dye and Gram-positive, that can be stained by the dye. Based on metabolism, the division is also divided into three main subgroups that include: Purple bacteria (photoautotroph and photoheterotroph that contain chlorophylls), Chemoautotrophic (consisting of free-living and symbiotic members), Chemoheterotrophic (also known as enteric bacteria). 

11. Spirochetes Spirochetes are long, thin, spiral shaped bacteria. They are gram- negative bacteria. They are known to cause sexual disease. They are distinct from the other types of bacteria due to their helical shape and movement.  Movement is made possible by the presence of an internal flagellar filament. In nature, Spirochetes can be found in water bodies, decaying organic matter, animals, plants and soil, etc. These group consists of both free-living and pathogenic organisms that have been shown to cause diseases in human beings and animals

12. Examples of Eubacteria Escherichia coli: Belongs to the Eubacteria  domain. It is classified into the Proteobacteria  phylum. It is rod-shaped and Gram-negative. E. coli  is commonly found in the gut of many different types of warm-blooded hosts, including humans. Most strains are harmless, but some can cause food poisoning and other illnesses.

13. Streptococcus pneumoniae : It is another common eubacteria . It belongs to the Firmicutes phylum. It is cocci shape, and it is Gram-positive.  S. pneumoniae  can be found on healthy hosts in the respiratory tract, nasal cavity, and sinuses. The bacteria can become pathogenic and spread to other parts of the body, often causing pneumonia and meningitis in immunocompromised hosts.

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