Pseudomonas

PSEUDOMONAS
Pseudomonas is a genus of gammaproteobacteria, belonging to the family Pseudomonadaceae containing 191 validly described species.
Recently, 16S rRNA sequence analysis has redefined thetaxonomy of many bacterial species. As a result, the genus Pseudomonas includes strains formerly classified in the genera Chryseomonas and Flavimonas.[3] Other strains previously classified in thegenus Pseudomonas are now classified in the genera Burkholderia and Ralstonia.
Characteristics
Members of the genus display the following defining characteristics:
 Rod shaped
 Gram-negative
 Oneor more polar flagella, providing motility
 Aerobic
 Non–spore forming
 positive catalase test
 positive oxidase test.
Other characteristics which tend to be associated with Pseudomonasspecies (with some exceptions) include secretion of pyoverdine, afluorescent yellow-green siderophore under iron-limiting conditions. Certain Pseudomonas species may also produce additional types ofsiderophore, such as pyocyanin by Pseudomonas aeruginosa and thioquinolobactin by Pseudomonas fluorescens. Pseudomonas species also typically give a positive result to the oxidase test, the absence of gasformation from glucose, glucose is oxidised in oxidation/fermentation test using Hugh and Leifson O/F test, beta hemolytic (on blood agar), indole negative, methyl red negative, Voges–Proskauer testnegative, andcitrate positive.
The members of the genus demonstrate a great deal of metabolic diversity, and consequently are able to colonise a wide range of niches.Their ease of culture in vitro andavailability of an increasing number of Pseudomonas strain genome sequences has made the genus an excellent focus for scientific research; the best studied species include P. aeruginosa in its roleas an opportunistic human pathogen, the plant pathogenP. syringae, the soil bacterium P. putida, and the plant growth promoting P. fluorescens.
Animal pathogens
Infectious species include P....