When combined with what we know about mutants affecting cellular morphology, these observations suggest that bacteria may fabricate specific shapes by directing the synthesis of two kinds of cell wall: a long-lived, rigid framework that defines overall topology, and a metabolically plastic peptidoglycan whose shape is directed by internal scaffolds. Since the advent of microbiology, cell shape has been an important criterion in the description and classification of bacterial species. Second, defects in cell shape are correlated with the presence of inappropriately placed, metabolically inert patches of peptidoglycan. Keep reading for examples of bacteria in each of these three. The three main bacteria shapes are coccus, bacillus and spiral. They are found everywhere and can be harmful, as in bacterial infections, or they can be beneficial, as in fermentation or decomposition. First, specific protein assemblies, nucleated by FtsZ, MreB or Mbl, appear to act as internal scaffolds that influence cell shape, perhaps by correctly localizing synthetic enzymes. Bacteria are the plural of bacterium, which are microscopic one-celled organisms. Two discoveries are particularly informative.
How they do so has been debated for decades, but recently experiment has begun to catch up with theory. Because shape is both stable and heritable, as is the ability of many organisms to execute defined morphological transformations, cells must actively choose from among a large repertoire of available shapes. Curved rod shape (similar to a comma) Spirochete. At the same time, this wall imposes on each cell a shape. Coccus Round shaped bacteria, Diplococci Cocci in pairs, Tetrad Cocci in groups of 4, Sarcinae Cocci in cube of 8, Staphylococci Large bunches of cocci, Streptococci Long chains of cocci, Bacillus Rod shaped bacteria.In free-living eubacteria an external shell of peptidoglycan opposes internal hydrostatic pressure and prevents membrane rupture and death.
0 kommentar(er)
