9. Pseiidomonas 



The genus Pseiidomonas has a large number of species many of 

 which are inadequately described and appear to be unobtainable 

 from any source. By definition, all motile strains of the genus 

 must have polar flagella, either polar monotrichous or polar multi- 

 trichous. Physiologically the most typical members of the genus 

 oxidize, but do not ferment, carbohydrates. Polar monotrichous or 

 multitrichous heterotrophic bacteria which ferment carbohydrates 

 with acid formation are better classified as Vibrio or Aeromoiias. 

 Still included in the genus are polar flagellated bacteria which 

 have no effect on carbohydrates. These are often mistakenly la- 

 beled Alcaligenes. The genus Lophomonas has been suggested for 

 a polar multitrichous or lophotrichous type which does not attack 

 carbohydrates. The type species, Fseudomonas aeruginosa, pro- 

 duces a water soluble greenish pigment, but many otherwise tvpical 

 species do not produce the pigment. For practical reasons the 

 genus will be discussed under three headings: (1) The ordinary 

 pseudomonads of fresh water, soil, and animal body; (2) the plant 

 pathogens; (3) the halophilic types. 



Cultures 



More than one hundred strains of the ordinary Pseiidomonas 

 from fresh water, soil, and the animal body were studied. These 

 were obtained from a variety of sources over a period of several 

 years. Among the major sources were Dr. W. D. Haynes of the 

 United States Department of Agriculture (U.S.D.A. ); Dr. Mac- 

 Donald Fulton, Stritch School of Medicine; WilHam Keller of 

 Philadelphia; the IlHnois State Health Laboratory, Chicago. All 

 of these cultures were identified physiologically and culturally as 

 well as morphologically. One culture, isolated from a five oyster, 

 showed mixed flagellation with a normal polar flagellum and one or 

 (more rarely) several lateral flagella of shorter wavelength. This 

 culture was physiologically typical of Pseiidomonas. 



The majority of the plant pathogens, some twenty species, 

 were obtained from Dr. Mortimer P. Starr of the University of 

 California. 



The halophihc types (fifteen strains) were mainly from R. A. 

 MacLeod of the Fisheries Research Board of Canada, Vancouver, 

 British Columbia. Aside from being halophilic these organisms 

 were typical Pseiidomonas species. 



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