Pseudomonadaceae

Taxobox
color = lightgrey
name = Pseudomonadaceae
regnum = Bacteria
phylum = Proteobacteria
classis = Gammaproteobacteria
ordo = Pseudomonadales
familia = Pseudomonadaceae
familia_authority = Winslow et al., 1917
subdivision_ranks = Genera
subdivision = "Azomonas"
"Azomonotrichon"
"Azorhizophilus"
"Azotobacter"
"Cellvibrio"
"Mesophilobacter"
"Pseudomonas"
"Rhizobacter"
"Rugamonas"
"Serpens"
The Pseudomonadaceae is a family of bacteria that includes the genera "Azomonas", "Azomonotrichon", "Azorhizophilus", "Azotobacter", "Cellvibrio", "Mesophilobacter", "Pseudomonas" (the type genus), "Rhizobacter", "Rugamonas", and "Serpens" [Skerman, McGowan and Sneath (editors): Approved Lists of Bacterial Names. Int. J. Syst. Bacteriol., 1980, 30, 225-420.] cite book | author = Cornelis P (editor). | title = Pseudomonas: Genomics and Molecular Biology | edition = 1st ed. | publisher = Caister Academic Press | year = 2008 | url=http://www.horizonpress.com/pseudo | id = [http://www.horizonpress.com/pseudo ISBN 978-1-904455-19-6 ] ] . The Azotobacteriaceae were recently published as belonging in this family as well.cite journal |author=Rediers H, Vanderleyden J, De Mot R |title=Azotobacter vinelandii: a "Pseudomonas" in disguise? |journal=Microbiology |volume=150 |issue=Pt 5 |pages=1117–9 |year=2004 |pmid=15133068 |doi=10.1099/mic.0.27096-0]

History

"Pseudomonad" literally means 'false unit', being derived from the Greek "pseudo" ("ψευδο" 'false') and "monas" ("μονος" 'a single unit'). The term "monad" was used in the early history of microbiology to denote single-celled organisms.Because of their widespread occurrence in nature, the pseudomonads were observed early in the history of microbiology. The generic name "Pseudomonas" created for these organisms was defined in rather vague terms in 1894 as a genus of Gram-negative, rod-shaped and polar-flagella bacteria. Soon afterwards, a very large number of species was assigned to the genus. Pseudomonads were isolated from many natural niches and a large number of species names was originally assigned to the genus. New methodology and the inclusion of approaches based on the studies of conservative macromolecules have reclassified many strains.

"Pseudomonas aeruginosa" is increasingly recognized as an emerging opportunistic pathogen of clinical relevance. Several different epidemiological studies indicate that antibiotic resistance is increasing in clinical isolatesFact|date=October 2007.

In the year 2000, the complete genome sequence of a "Pseudomonas" species was determined; more recently the sequence of other strains have been determined including "P. aeruginosa" strains PAO1 (2000), "P. putida" KT2440 (2002), "P. fluorescens" Pf-5 (2005), "P. fluorescens" PfO-1 and "P. entomophila" L48. Several pathovars of "Pseudomonas syringae" have been sequenced, including pathovar tomato DC3000 (2003), pathovar syringae B728a (2005), and pathovar phaseolica 1448A (2005).cite book | author = Cornelis P (editor). | title = Pseudomonas: Genomics and Molecular Biology | edition = 1st ed. | publisher = Caister Academic Press | year = 2008 | url=http://www.horizonpress.com/pseudo | id = [http://www.horizonpress.com/pseudo ISBN 978-1-904455-19-6 ] ]

Distinguishing characteristics

* Oxidase positive - this is due to the presence of cytochrome c oxidase enzyme
* Non-fermentative
* Many metabolise glucose by the Entner Doudoroff pathway mediated by the following enzymes - 6 phosphoglyceraldehyde dehydrogenase and aldolase
* Polar flagella, enabling motility
* Many members produce derivatives of the fluorescent pigment "pyoverdin".cite journal |author=Meyer J |title=Pyoverdines: pigments, siderophores and potential taxonomic markers of fluorescent "Pseudomonas" species |journal=Arch Microbiol |volume=174 |issue=3 |pages=135–42 |year=2000 |pmid=11041343 |doi=10.1007/s002030000188]

The presence of oxidase, polar flagella and inability to carry out fermentation differentiate Pseudomonads from Enterobacteriaceae: [Krieg, N.R. (Ed.) (1984) Bergey's Manual of Systematic Bacteriology, Volume 1. Williams & Wilkins. ISBN 0683041088] .

References