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Liver damage by intra-ileal treatment with Salmonella 3,10:r:- extract as studied by light and electron microscopy.
Abstract
Salmonella 3, 10: r-organisms discovered from human cases of food poisoning at the Indian Veterinary Research Institute (Gupta et al. 1980) are bacilli with numerous pili on their surface (YashRoy et al., 1990, YashRoy 1993a). Sonicated cell-free extract prepared from the Salmonella 3, 10; r organisms, when given intra-ileally, is known to produce degenerative changes in the ileum (YashRoy 1990). It has been suggested that Gram-negative bacterial endotoxin (s) may leak across the bowel so as to enter the circulation (Ledingham et al. 1988). Keeping this in view, together-with the initial findings from our earlier investigations (YashRoy et al. 1993) light and electron microscope studies on liver of rabbits treated injected with cell free sonicated Salmonella 3,10:r:- extract studied 18 hr after this treatment revealed centri-lobular necrosis of liver with severe damage to hepatic cells.
Outer membrane vesicles (OMVs) are 30–200 nm diameter-sized bacterial outer membrane-bounded spherical vesicles containing proteins, virulence signals, DNA fragments, etc., released by all known Gram-negative microorganisms in cultures and natural habitats of soil, water bodies, oceans, animal/plant bodies, etc. The outer membrane of Gram-negative microbes protrudes out in pockets, containing a part of the periplasm, which is then pinched off as OMVs. The membrane enclosing the OMVs contains phospholipids, lipopolysaccharide, and select membrane proteins. Soluble proteins, DNA fragments, virulence determinants, etc. are normally present inside the OMV compartment. OMVs thus traffic a protected repertoire of bacterial molecules into the environment for intraspecies, interspecies, and interkingdom signaling. Transfer of DNA fragments can carry out genetic transformations among microbes. OMVs may signal formation of bacterial biofilms and screen bacteria from phages, antibiotics, antimicrobial peptides, etc. OMVs contain hydrolytic enzymes for breaking down lipids, peptidoglycan, and proteins, thereby enabling bacteria to lyse competing microbes and digest and absorb food reserves available nearby. OMVs are so versatile that bacteria deploy them as combat arsenal for their survival and spread. Isolated OMVs are also being pitted for use as organism-free vaccines.
Outer membrane vesicles (OMVs) are 30-200. nm diameter-sized bacterial outer membrane-bounded spherical vesicles containing proteins, virulence signals, DNA fragments, etc., released by all known Gram-negative microorganisms in cultures and natural habitats of soil, water bodies, oceans, animal/plant bodies, etc. The outer membrane of Gram-negative microbes protrudes out in pockets, containing a part of the periplasm, which is then pinched off as OMVs. The membrane enclosing the OMVs contains phospholipids, lipopolysaccharide, and select membrane proteins. Soluble proteins, DNA fragments, virulence determinants, etc. are normally present inside the OMV compartment. OMVs thus traffic a protected repertoire of bacterial molecules into the environment for intraspecies, interspecies, and interkingdom signaling. Transfer of DNA fragments can carry out genetic transformations among microbes. OMVs may signal formation of bacterial biofilms and screen bacteria from phages, antibiotics, antimicrobial peptides, etc. OMVs contain hydrolytic enzymes for breaking down lipids, peptidoglycan, and proteins, thereby enabling bacteria to lyse competing microbes and digest and absorb food reserves available nearby. OMVs are so versatile that bacteria deploy them as combat arsenal for their survival and spread. Isolated OMVs are also being pitted for use as organism-free vaccines. Cite as: YashRoy, R. C. (2017). “Outer membrane vesicles of gram-negative bacteria:
nanoware for combat against microbes and macrobes,” in Nanostructures
for Antimicrobial Therapy, eds A. Ficai and A. H. Grumezescu
(Amsterdam: Elsevier Inc), 341–367. doi: 10.1016/B978-0-323-46152-8.00
015-9
Beginner's guide for practical electron microscopy - biomedical applications.