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Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archaea). Generally, the basic morphologies are spheres (coccus) and round-ended cylinders or rod shaped ...
Bacillus (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum Bacillota, with 266 named species.The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural Bacilli is the name of the class of bacteria to which this genus belongs.
Both gram-positive and gram-negative bacteria commonly have a surface layer called an S-layer. In gram-positive bacteria, the S-layer is attached to the peptidoglycan layer. Gram-negative bacteria's S-layer is attached directly to the outer membrane. Specific to gram-positive bacteria is the presence of teichoic acids in the cell wall. Some of ...
Streptococcus pyogenes is a species of Gram-positive, aerotolerant bacteria in the genus Streptococcus.These bacteria are extracellular, and made up of non-motile and non-sporing cocci (round cells) that tend to link in chains.
Cell shape is generally characteristic of a given bacterial species, but can vary depending on growth conditions. Some bacteria have complex life cycles involving the production of stalks and appendages (e.g. Caulobacter) and some produce elaborate structures bearing reproductive spores (e.g. Myxococcus, Streptomyces).
Staphylococcus aureus (/ ˌ s t æ f ɪ l ə ˈ k ɒ k ə s ˈ ɔːr i ə s,-l oʊ-/, [16] [17] Greek σταφυλόκοκκος ' grape-cluster berry ', Latin aureus, ' golden ') is a facultative anaerobic, gram-positive coccal (round) bacterium also known as "golden staph" and "oro staphira". S. aureus is nonmotile and does not form spores. [18]
For example, L-forms of the rod-shaped bacterium Bacillus subtilis appear round when viewed by phase contrast microscopy or by transmission electron microscopy. [ 8 ] Although L-forms can develop from Gram-positive as well as from Gram-negative bacteria , in a Gram stain test , the L-forms always colour Gram-negative, due to the lack of a cell ...
For example, E. coli is a rod-shaped bacterium that can be described as "a bacillus", but it stains Gram-negative and does not belong to the genus Bacillus or the class Bacilli. Some microbiologists have forsaken the general "bacillus" term because of the confusion it can create.