44. Proteus 



The genus Proteus is fairly well defined physiologically. Four 

 species are commonly recognized: Proteus mirahilis, Proteus vul- 

 garis, Proteus morganii, and Proteus rettgeri. The last named of 

 these has some characteristics relating it to the SalmoneUa. A 

 group of bacteria commonly referred to as the "Providence group" 

 probably should be classified as Proteus. From the large collec- 

 tion of Dr. MacDonald Fulton were selected seventy-five strains 

 for study. These were evenly divided among the four species and 

 the Providence group. 



Flagellar Characteristics 



All the strains studied showed peritrichous flagellation. The 

 number of flagella varied greatly from strain to strain and has little 

 taxonomic significance. The cultures of P. mirahilis and P. vulgaris 

 which showed the "swarming" phenomenon on agar generally 

 showed the greatest density of flagella. P. rettgeri strains usually 

 showed the fewest flagella. 



Normal and curly flagella were observed in all strains studied 

 with the exception of P. rettgeri. In this species only one of the 

 twelve strains studied showed an occasional curly flagellum. As 

 may be seen in the illustrations ( Fig. 46 ) , an individual organism 



Fig. 46. a, b. Proteus mirahilis, Fulton 52. In a is illustrated the typical 

 normal peritrichous flagella of Proteus. In b is shown the corresponding curly 

 flagella on the same strain. The organism in a was stained from a slightly 

 alkaline suspension while that in b from a slightly acid suspension, both 

 from the same culture. 



c. P. vulgaris. Mainly coiled flagella with two normal flagella at the top 

 of the soma. 



d. Proteus sp., Providence type. Semicoiled flagella. These were quite 

 rare in the Proteus group and have not been definitely observed in other kinds 

 of bacteria. 



e. P. morganii. Normal and curly flagella on the same individual. 



f. P. mirahilis. Many curly flagella and one normal flagellum on the same 

 individual. These mixed types of flagellation were seen mainly in slides pre- 

 pared from su.spensions at pH 6.5 to 7.5. 



g. h, i, j. P. morganii. These figures show various double curvature arrange- 

 ments: proximal end curly, distal normal; proximal normal, distal curly; ends 

 normal, center curly; alternating normal and curly. 



k. P. mirahilis, Fulton 52. A filamentous form with mainly normal flagella. 

 A curly flagellum may be seen on the right end. 



a-j. From E. Leifson, S. R. Carhart, and M. Fulton, /. Bactcriol. 69, 73-82 

 (1955). 



108 



