Bacteria are classified by direct examination with a light microscope according to their morphology and regulation.
The basic shapes are spherical (coccus) and round spherical cylinders (bacillus). But there may be others like twisted helical cylinders (spirochetes), curved cylinders in one plane (Selenomonads) and unusual morphology (such as the square Archaea Haloquadratum). They also adjust the diplo, tetrad, staphylos, streptos, palizadas, etc.
Video Bacterial cellular morphologies
Coccus
A coccus (plural cocci , from the Latin coccinus (red) and derived from the Greek kokkos (berry) ) are microorganisms (usually bacteria) whose overall shape is round or almost spherical. Describing bacteria as coccus, or balls, distinguishes them from bacillus, or stems. This is the first of many taxonomic features to identify and classify bacteria based on binomial nomenclature.
Settings
Coccoid bacteria often occurs in a characteristic setting and these forms have a special name as well; listed here are the basic forms as well as the representative bacterial genera:
- pairs or diplococci (e.g. Neisseria )
- groups of four or eight known respectively as tetrad and sarcina (eg Micrococci )
- bead-like chains (eg
) - grapelike clusters (eg Staphylococcus )
Diplococcus
A diplococcus (plural diplococci ) is a round bacteria (coccus) that usually occurs in pairs of two joined cells. Examples are Streptococcus pneumoniae , Moraxella catarrhalis , Neisseria gonorrhoeae and Neisseria meningitidis .
The name comes from diplo, which means double, and coccus, which means berry. This is because round berries, such as diplococcus, and diplococci come in pairs of two.
In the past, the genus of Diplococcus was recognized, but not in use.
Coccobacillus
A coccobacillus (plural coccobacilli ) is a type of stem-shaped bacteria. The word coccobacillus reflects the transitional form between coccus (ball) and bacillus (elongated). Coccobacilli rods are very short and wide so resemble cocci. Haemophilus influenzae and Chlamydia trachomatis are coccobacilli. Aggregatibacter actinomycetemcomitans are common negative coccobacillus grams in subgingival plaques. Acinetobacter strains can grow on solid media as coccobacilli.
Coxiella burnetti is also a coccobacillus.
Clinical interests
Important human pathogens caused by coccoid bacteria that include staphylococci infections, some types of food poisoning, some urinary tract infections, toxic shock syndrome, gonorrhea, and some forms of meningitis, throat infections, pneumonia, and sinusitis.
Bacteria are known to develop special properties for survival in their ideal environment. Bacteria caused by disease depend on bacterial physiology and their ability to interact with their environment, including the ability to change shape. The researchers found a protein that allows the bacteria Vibrio cholerae to transform into a bottle opening that may help twist in - and then escape - the protective mucus that lines the inside of the intestine.
Maps Bacterial cellular morphologies
Bacillus
A bacillus (bacilli plural) is a rod-shaped bacterium. Although Bacillus , capitalized and italicized, specifically refers to the genus, the word bacillus (plural bacilli ) may also is used to describe stem-shaped bacteria, and in this sense, bacilli are found in various groups of bacterial taxonomies. There is no relationship between the bacterial form and the color in Gram staining.
Bacilli usually divide in the same plane and are solitary, but may combine to form diplobacilli, streptobacilli, and palisade.
- Diplobacilli: Two bacillas are arranged side by side with each other.
- Streptobacilli: Bacilli is arranged in chains.
- Coccobacillus: Oval and similar to coccus (circular bacteria).
Spiral
Spiral bacteria form the morphology of the third major bacterial cell. Spiral bacteria can be classified as spirillas, spirochetes, or vibrios based on the number of bends per cell, cell thickness, cell flexibility, and motility.
References
See also
- Plastic morphology plasticity
- Ferdinand Cohn - gives the first form of bacteria named
External links
- Picture Gallery of Bacteria
Source of the article : Wikipedia
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