Bdellovibrio

Aerobic spiral and curved motile gram-negative bacteria. Bdellovibrio, Campylobacter (C. jejuni, diarrhea), Helicobacter (H. pylori, gastric ulcers), Spirillum... 

Fig. 1. Dendrogram of relationships among photosynthetic prokaryotes and their relatives, after Stackebrandt and Woese [2], Five bacterial phyla [1] containing photosynthetic members are shown. The exact relationship of Heliobacterium chlorum to the gram-positive bacteria is not yet known. Not shown are the other five phyla without known photosynthetic-members peptidoglycan-less bacteria bacteroids, cytophagas and flavobacteria spirochaetes and leptospiras bdellovibrios, myxococci, and certain S and SOj reducers and Deinococcus. PS = photosynthetic for further explanation, see text.

The majority of bacteria are Gram-negative organisms and the coli-aerogenes group account for only a small fraction. Bdellovibrio bacteri-ovorus which attacks bacteria reduces the bacterial numbers. Antibiotic-resistant aeromonads have been isolated from some samples. Nitrosomonas spp. are also present and are responsible for nitrification of ammonia. 

Parasitism. In this direct interaction a parasite cell or particle attaches Itself to a host cell and makes a partial or total penetration into it, where it then uses the host s biomass or metabolic activities to grow and reproduce itself. Examples are provided by the parasitism of viruses on bacteria and other microorganisms, by the parasitism of the very small bacterium Bdellovibrio on other bacteria, and by the parasitism of bacteria on protozoa (30,74,75). Parasitism is characterized by a variable but always high degree of host specificity. That is, a given parasite is able to Infect only a limited number of hosts, and in some cases, the number may be small Indeed. 

CAO H, HE s, WANGM H, Hou s, LU L and YANG X (2012) Bdellovibrios, potential biocontrol bacteria against pathogenic Aeromonas hydrophila. Vet Microbiol, 154, 413 18. 

The filaments of Bdellovibrio bacteriovorus and Vibrio metchnikovii are sheathed. The core is of similar construction to that of unsheathed fila-... 

In rivers containing large numbers of bacteria, parasite vibrios of the genus Bdellovibrio are common. These monoflagellated vibrios attach to Gram-negative bacteria, penetrate the envelope and internally parasitise the host. Polysaccharide capsules appear to provide little protection to the host. However rough mutants of Salmonellae typhimurium and E. coli (i.e. 

Although the cell wall of Spirillum serpens lost much of its rigidity after infection with Bdellovibrio bacteriovorus, the peptidoglycan remained as a discrete cell-wall layer. Comparisons of the abilities of some oligosaccharyl-peptides (obtained from the peptidoglycans of Staph, aureus and Lactobacillus plantarurri) to induce arthritis in rats showed that, at least, one disaccharide unit linked to a peptide is necessary. The presence of teichoic acid did not have any effect. 

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