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Bacteria display a large diversity of cell morphologies and arrangements. 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).
Spirillum is a of Gram-negative bacteria in the family Spirillaceae of the Nitrosomonadales of the Betaproteobacteria. [1] [2] [3] There are two species of Spirillum with validly or effectively published names - Spirillum winogradskyi and Spirillum volutans.
In 1832, the genus Spirillum was created and encompassed an array of helical bacteria. In 1957, the large genus was reviewed and narrowed to include 19 species based on morphology and a few other physiological characteristics.
Leptospira are spiral-shaped bacteria that are 6-20 μm long and 0.1 μm in diameter with a wavelength of about 0.5 μm. [18] One or both ends of the spirochete are usually hooked. Because they are so thin, live Leptospira are best observed by darkfield microscopy .
[31] [32] [33] Bacteria may alter their shape by simpler transitions from rod to coccoid (and vice versa) as in Escherichia coli, [34] by more complex transitions while establishing multicellularity [31] or by the development of specialized cells, structures or appendages where the population presents a pleomorphic lifestyle. [35]
Bacterial morphological plasticity refers to changes in the shape and size that bacterial cells undergo when they encounter stressful environments. Although bacteria have evolved complex molecular strategies to maintain their shape, many are able to alter their shape as a survival strategy in response to protist predators, antibiotics, the immune response, and other threats.
Under aerobic growth photosynthesis is genetically suppressed and R. rubrum is then colorless. After the exhaustion of oxygen, R. rubrum immediately starts the production of photosynthesis apparatus including membrane proteins, bacteriochlorophylls and carotenoids, i.e. the bacterium becomes photosynthesis active. The repression mechanism for ...
Treponema pallidum, formerly known as Spirochaeta pallida, is a microaerophilic, gram-negative, spirochaete bacterium with subspecies that cause the diseases syphilis, bejel (also known as endemic syphilis), and yaws. [1]