FAMILY IV. PSEUDOMONADACEAE 



205 



I. Gelatin not liquefied 

 II. Gelatin liquefied. 



Key to the species of genus Mycoplana. 



1. Mycoplana dimorpha. 



2. Mycoplana bullata. 



1. Mycoplana dimorpha Gray and 

 Thornton, 1928. (Cent. f. Bakt., II. Abt., 

 73, 1928,82.) 



di.mor'pha. Gr. adj. diniurphus two forms. 



Short, curved and irregular rods, 0.5 to 

 0.7 by 1.25 to 4.5 microns, showing branch- 

 ing especially in young cultures. Originally 

 reported as "polar, peritrichous". Draw- 

 ings show some cells with a polar flagellum 

 and others where the several flagella shown 

 could represent a tuft of polar flagella. 

 Cultures preserved in the American Type 

 Culture Collection have been retested (T. 

 H. Lord, Manhattan, Kansas; F. E. Clark, 

 Beltsville, Maryland) and show typical 

 pseudomonad cells, i.e., straight rods with a 

 single polar flagellum. Meanwhile P. H. H. 

 Gray (Macdonald College, Quebec) reports 

 that his cultures still show branching cells 

 on the media he uses. Gram-negative. 



Gelatin colonies: Circular, bufi", smooth, 

 resinous, entire. 



Gelatin stab: No liquefaction. Growth 

 filiform. 



Agar colonies: Circular, buff, convex, 

 smooth, glistening, entire. 



Agar slant: Filiform, white, convex, 

 glistening, entire. 



Broth: Turbid, with surface ring. 



Nitrites not produced from nitrates, but 

 gas evolved in fermentation tubes. 



Starch hydrolyzed. 



No acid from carbohydrate media. 



Attacks phenol. 



Aerobic. 



Optimum temperature, below 30° C. 



Source : Only one strain was found in soil 

 by Gray and Thornton {loc. cit.). Wood 

 (Aust. Jour. Marine and Freshwater Res., 

 4, 1953, 184) identifies 1010 cultures out of 

 2969 cultures isolated from Australian 

 marine habitats as belonging to this species. 

 Some appeared on svibmerged glass slides as 

 attached forms. A diversity of characters 

 was found in these cultures, indicating that 

 many of them should not have been identi- 



fied as belonging to this species or even to 

 this genus. For example, while it is stated in 

 one place that carbohydrate fermentation 

 is feeble, it is stated in another place that 

 about 50 per cent of the cultures actively 

 fermented maltose and sucrose, these sugars 

 being fermented more actively than glucose. 

 Some cultures are reported as attacking 

 cellulose, others as attacking alginates or 

 even chitin. In other words many of the cul- 

 tures identified as Mycoplana dimorpha 

 possessed characters not ascribed to the 

 species by Gray and Thornton. Apparently 

 all cultures from marine habitats that were 

 Gram-negative branching forms were identi- 

 fied as Mycoplana dimorpha unless they 

 showed a yellow, pink or lemon-yellow chro- 

 mogenesis. Wood's work would indicate that 

 branching, polar flagellate species of very 

 diverse physiologies exist in marine habitats 

 that are as yet scarcely studied from the 

 standpoint of the species present. M. E. 

 Norris of the Pacific Fisheries Experiment 

 Station, Vancouver, B.C. reports (personal 

 communication. May, 1954) that she also 

 finds Gram-negative, branching, polar 

 flagellate organisms in sea water. 



Habitat: Probably widely distributed in 

 soil. Possibl}^ also found in marine habitats. 



2. Mycoplana bullata Gray and Thorn- 

 ton, 1928. (Cent. f. Bakt., II Abt., 73, 1928, 

 83.) 



bul.la'ta. L. adj. bullatvs with a knob. 



Rods curved or irregular in shape, branch- 

 ing, 0.8 to 1.0 by 2.25 to 4.5 microns. Origi- 

 nally stated to be either "polar or peri- 

 trichous" in its flagellation, but recent 

 studies show that the American Type Cul- 

 ture Collection culture of this organism is 

 polar flagellate. It resembles Mycoplana 

 liiinurpha in this respect. Gram-negative. 



Gelatin colonies: Circular, buff, smooth, 

 glistening; edge diffuse. Gelatin partially 

 liquefied. 



