Kingdom Mychota [ 25 



Family Mycobacteriacea [Mycobacteriaceae] Chester 1907. Family Actinomyce- 

 taceae Buchanan in Jour. Bact. 3: 403 (1918). Family Streptomycetaceae Waksman 

 and Henrici 1943. Characters of the order. Three genera require discussion. 



Streptomyces Waksman and Henrici 1943. The original name of this genus is 

 Streptothrix Cohn (1875); there is an older genus Streptothrix among plants, and 

 the numerous species of the present genus have generally been included in Actino- 

 myces. Cultures are readily isolated from air or soil. They appear as slowly growing 

 colonies which may at first be of various colors and have shiny surfaces. Their texture 

 is tough; a blunt needle will more often tear a colony from the medium than pene- 

 trate it. As the colonies grow, they become truncate; the exposed surfaces become 

 white and powdery; pigments, black, brown, red, or yellow, in various races, are 

 produced, and discolor the medium. The toughness of the colonies is a consequence 

 of their structure, of myriad crooked branching filaments about 1|J. in diameter, 

 without joints; the white and powdery surface is produced by myriad conidia released 

 in basipetal succession. The cultures are of an odor which may be described as that 

 of earth under the first rain after drouth: undoubtedly, this familiar odor is that of 

 Streptomyces in the soil. Drechsler (1919), from careful study of several species of 

 Streptomyces, concluded that they are fungi; their filaments are, however, much 

 finer than those of fungi, and no definite nuclei have been seen. 



Certain species of Streptomyces cause a scabbiness of potatoes. Except for this, the 

 genus was for a long time regarded as quite unimportant. When the capacity of the 

 fungus Penicillium notatum to inhibit the growth of bacteria had been observed, 

 and had led to the discovery of the drug penicillin, Waksman, the leading authority 

 on the classification of Actinomycetalea, sought comparable drugs produced by 

 Streptomyces, and had the great success of discovering streptomycin. 



Actinomyces Bovis Harz 1877 is one of several species of the same general nature 

 as Streptothrix which are pathogenic to animals. It causes lumpy jaw of cattle. 



Mycobacterium Lehmann and Neumann 1896 is typified by M. tuberculosis, the 

 agent of one of the most important diseases of man, supposed originally to have 

 attacked cattle, and to have spread around the world with European cattle. It is a 

 chronic disease, destroying the tissues slowly and producing a nugatory sort of im- 

 munity which makes it possible to test for the disease, but does not check it. The 

 cells are recognized in sputum and in diseased tissues by the acid fast reaction: the 

 dye carbol fuchsin must be applied hot in order to color them; once it has done so, 

 it does not wash out in acid alcohol. It is cultivated with difficulty. The growth is 

 dry, powdery, wrinkled, with an odor described as sickening-sweet. It consists of 

 branching filaments which break up readily into rod-shaped or irregular fragments. 



Lesions of leprosy contain acid fast organisms named Mycobacterium leprae. Gay 

 (1935) has discussed the results of attempts to cultivate this species. They have 

 yielded either "diphtheroid" cells or a "streptothrix." He concludes that most of 

 the reports are of the same organism reacting variously to various conditions. 



Order 3. Caulobacterialea [Caulobacteriales] Henrici and Johnson in Jour. Bact. 

 29: 4 (1935). 



Aquatic bacteria, the cells of most examples secreting gelatinous matter in such a 

 manner as to produce stalks. Henrici and Johnson provided a system of four families, 

 five genera, and nine species. Stanier and van Niel (1941) rejected the group as 

 artificial, placing some of the genera among Eubacteria and leaving others unplaced. 

 The order may be maintained for the accommodation of the latter and divided into 

 two families. 



