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Listeria Grayi
''Listeria grayi'' is a species of bacteria. It is a Gram-positive, facultatively anaerobic, motile, non-spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...-forming bacillus. It is non-hemolytic. The species was first proposed in 1966. It is named after M.L. Gray, an early researcher in '' L. monocytogenes'' There are two subspecies of ''L. grayi'': ''L. gray'' subs. ''grayi'', and ''L. grayi'' subsp. ''murrayi''. ''Listeria murrayi'' (named after a co-founder of '' L. monocytogenes'') was originally a separate species of ''Listeria'' when proposed in 1971. However, there was controversy over whether ''L. grayi'' and ''L. murrayi'' were the same species, or belonged in genus ''Listeria'' altogether. In 1974, researchers suggested that a new genus be created for the two species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-positive
In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through an optical microscope. This is because the thick peptidoglycan layer in the bacterial cell wall retains the stain after it is washed away from the rest of the sample, in the decolorization stage of the test. Conversely, gram-negative bacteria cannot retain the violet stain after the decolorization step; alcohol used in this stage degrades the outer membrane of gram-negative cells, making the cell wall more porous and incapable of retaining the crystal violet stain. Their peptidoglycan layer is much thinner and sandwiched between an inner cell membrane and a bacterial outer membrane, causing them to take up the counterstain ( s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
