Any gene which are rod shaped, gram positive in nature, aerobic or anaerobic bacteria and majorly found in soil and water are termed to be Bacillus bacteria. In general science the term bacillus means cylindrical or rod like bacteria. One of the largest species of Bacillus is B. megaterium, which is approx 1.5 μm (micrometres; 1 μm = 10−6 m) across by 4 μm long. These bacteria majorly occur in chains. Ferdinand Cohn in 1877 provided a full description about two different forms of hat bacillus. One is that it could be killed when kept in exposure with heat and another which shows restivity towards heat. But at present discovery, it is known that Bacillus species can form dormant spores under adverse environmental conditions and these endospores have viability for a long period of time. Endospores are resistant to heat, chemicals, sunlight and they are widely distributed nature, majorly in soil, from which they invade dust particles.
Classification of Bacillus
Nature of cell wall of Bacillus
The structure which is found outside the cell, which forms a second barrier between the bacterium and the environment is called cell structure. The cell wall also maintains the rod shape and withstands the pressure generated by the cell's turgor. The composition of the cell wall of Bacillus is teichoic and teichuronic acids. The very first bacteria for which the role of actin as cytoskeleton in cell shape determination and peptidoglycan synthesis was identified in Bacillus subtilis. One of the major roles of the cytoskeleton is to maintain the shape of bacteria.
These bacteria are mainly in rod shape, endospore-forming aerobic or facultatively anaerobic, Gram-positive bacteria whereas in some species they are gram-negative in nature. The single-cell has a single spore and these spores are resistant to heat, cold, radiation, desiccation, and disinfectants.
Ecological and Clinical Importance of Bacillus Bacteria
These Bacillus bacteria have the capability to survive in extreme conditions like high pH (B. alcalophilus), high temperature (B. thermophilus), and high salt concentrations, because of this nature they are ubiquitous in nature.
One of species of Bacillus bacteria i.e. Bacillus thuringiensis has the ability to produce toxins that can kill insects and thus they are insecticides in nature.
Bacteria B. siamensis can inhibit plant pathogens from entering as they have antimicrobial compounds in them.
Few species of Bacillus act as naturally competent for DNA uptake by transformation.
Medical Use of Bacillus Bacteria
Bacillus subtilis acts as an important model organism along with that it is also a notable food spoiler which lead to ropiness in bread and related food.
Bacillus subtilis also does production and secretion of antibiotics.
Bacillus coagulans also act as a food spoilage of highly acidic, tomato-based products.
Disease Caused by Bacillus
Some of the common disease caused by Bacillus bacteria are:
Infections caused by Bacillus subtilis are endocarditis, pneumonia, and septicemia. This problem mainly occurs in patients who have an immune disorder.
Bacillus anthracis, as it causes skin, lungs, and bowel infection and these diseases are deadly to the human body.
Bacillus cereus causes food spoilage which can cause food poisoning.
Gram positive Bacilli form bacteria are: Actinomyces, Clostridium, Bacillus or gram-negative bacteria, e.g. Escherichia, Klebsiella, Salmonella, Streptobacillus, etc.
They have capability of serving at high temperatures i.e. at 4200 C.
They are mostly non-parasitic and free living in nature.
They are known to be one of the most abundantly found bacteria.
Bacillus Are Further Classified Into Different Types Based on Rod-Shape Cells
Bacillus: Single unattached cell, that looks like a rod. Examples are Bacillus cereus, Salmonella enterica, etc.
Diplobacilli: In these bacteria two rods are attached to each other and found in pairs after cell division. Examples are Moraxella bovis, Klebsiella rhinoscleromatis, etc.
Streptobacilli: In them bacilli are arranged in a single chain due to cell division in a single plane. Examples are Streptobacillus moniliformis, Streptobacillus felis, etc.
Coccobacilli: They are of oval shape and short in comparison to other bacteria. Examples: Chlamydia trachomatis, Haemophilus influenzae, Gardnerella vaginalis, etc.
Palisades: In these bacteria cells bends after cell division and they arranged themself in a palisade.Example: Corynebacterium diphtheriae