Microbiology Now: The Mystery of the Missing Peptidoglycan Verrucomicrobiales ha
ID: 143698 • Letter: M
Question
Microbiology Now: The Mystery of the Missing Peptidoglycan Verrucomicrobiales have prosthecae and interior membrane-bound structures, in addition to a clearly identifiable peptidoglycan cell wall. Mycoplasmas have increased amounts of membrane sterols to help resist osmotic lysis, some also have yellow carotenoids to protect against damage from reactive oxygen species. Planctomycetes have cell membranes that invaginate to form an internal membranous structure they were thought to lack peptidoglycan until cryo-electron tomography was used to look for it Deinococci lack lipid A and may be red or pink from carotenoids Flexibacteria contain carotenoids or flexirubins in their cell membranesExplanation / Answer
1.verrucamicrobiales: These are prosthecate bacteria with membrane out growths called prosthecae which may sometimes also contain fimbriae. They have thin but still identifiable ppeptidoglycan. They have inner membranes that isolate the DNA and form a sort of early nucleus.
2. mycoplasma: mycoplasma belong to the class of mollicutes bacteria, 'molli' means soft, pliable and 'cutes' means skin or cell membrane . They donot have cell wall but only cell membrane rich in sterols which gives the membrane fluidity at different temperature ranges, protection from plasmolysis and makes them resistant to microfilters. Not all mycoplasma species have sterols, those that lack sterols will have carotenoids in the form of carotenols(alcohol derivatives of carotenoids), these give resistance to Reactive oxygen species.
3. planctomycetes: the statement mentioned about these bacteria is very true. They contain membrane bound inner structures called the paryphoplasma(ribosome-free space), pirellulosome (ribosome- space) and nucleoid planctomycetes were the only bacteria with theseinternal compartment until the discovery of Poribacteria Until cryo- tomography it was thought that their membranes were made of glutamate rich glycoproteins and not peptidoglycans.
4. Deinococci: These bacteria contain cell wall structure that has both features of gram positive and gram negative; lipid A is a definitive feature of all gram negative bacteria, it helps in anchorage of the lipopolysaccharide to cell wall and is antigenic in nature. Deinococci contain carotenoids called deinoxanthins that protect the cells from radiation and give pink colonies in culture.
5. flexibacteria: These bacteria contain carotenoids that give them pink or red colour when cultured in vitro. These pigments protect them from U V radiation. Flexirubins are the chemosynthetic pigments and markers for flexibacteria.