\.\\ir MliCIIANISMS 



173 



teria in ajj;ar and ('X1)()S(h1 the plates (o the 

 air. A white culture of an actiiKMnycele. des- 

 i«j;nate(l as "St reptolhrix," l)ul delinilely ;i 

 Stn i>l(>nii/C( s, dexeloped on the plat(>s. W'lien 

 this cuhure was transt'en-ed to a suspension 

 of dead staphx-loeoeci in sterile saline solu- 

 tion, the bacterial suspension became clari- 

 fied in 'M\ liours, acconipanicHl by flaky 

 j;rowth of the actinoniycete. When the lysed 

 emulsion was Hltered, it was found capable 

 of dissolvinj^ a Uvsh suspension of dead bac- 

 teria. This culture could attack all staphylo- 

 cocci tested, as well as certain other bactoi'ia, 

 such as }^s. aeruginosa; howe\er, it was in- 

 acti\"e ui)on .1/. tuhcrcitlosis and K. aili. T\\v 

 lysetl material was desiji;nated as a mycolij- 

 satr. It did not possess the toxicity of a non- 

 lysed suspension, l)ut retained its antig(Miic 

 properties. Gratia later asserted that the 

 "Streptothrix" culture was also able to at- 

 tack living cells of bacteria, except E. coli 

 and Ehcrthdla typhosa, which had to be first 

 killed by heat. 



In 1935, l^orodulina demonstratetl the 

 ability of certain actinomycetes to dissohe 

 various spore-forming bacteria, especially 

 Bacillus subtilis. She emphasized that the 

 lytic substance of actinomycetes is produced 

 in acid media but not in basic. The substance 

 was resi.stant to heat, although it was de- 

 stroyed in the autoclave. Xakhimovskaia 

 (1937) also demonstrated the ability of vari- 

 ous actinomycetes to form a lytic substance, 

 which is excreted into the medium. The sub- 

 stance inhibited the growth of various bac- 

 teria and even dissolved them. 



Krassilnikov and Koreniako (1939) con- 

 sidered this property of actinomycetes to lyse 

 certain bacterial cells as due to ly.sozyme, 

 which was first described l)y Fleming in 1922. 

 Kriss (1940) isolated from a culture of S. 

 violaceus, a thermostable substance which 

 was designat ed a s />ac7f'/v'o///.s/// . Thi s subst a nee 

 was soluble in water and was beliexed to be 

 diflerent from bacteriophage and identical 

 with Ivsozvme. Kriss reached the i"ather sig- 



nihcanl couclusion that actinomycetes pro- 

 duce various substances that act upon bac- 

 teria eithei- in an antagonistic or in a lytic 

 nKinnei'. 



The most extensive studies ou the bac- 

 teriolytic actixities of certain actinomycetes 

 have been made by Welsch, following in the 

 footstei)s of (iratia and his associates. lie- 

 ginning in 193(1, he and hiscollaboratorshave 

 published a large ninnber of pa))ers on this 

 lytic principle. 



Welsch first obtained a bacteriolytic jirep- 

 aration from a culture of .S. albus. It pos- 

 .<essed strong activites and was heat-labile; 

 it was destroyed at (h')° in 2 hours and at 80° 

 in ") minutes. At low temperatures, it re- 

 mained stable for many months; at pH 4.0, 

 it was destroyed in 24 hours. The active sub- 

 stance was precipitated by ammonium sul- 

 fate, ethyl alcohol, and acetone. The produc- 

 tion of this bacteriolytic substance was 

 closely rclatetl to the sporulation of the or- 

 ganism; there was no relation, however, be- 

 tween its production and autolysis of culture. 

 This substance was designated as actinomy- 

 c(tin. 



Welsch further repoi'ted that some of the 

 activity of actinomycetin in the filtrate was 

 lost on passage through bacterial filters. 

 Three groups of l)acteria were recognized in 

 their relation to actinomycetin: 



1 . Those bacteria which were lysed by the 

 aiiueous extract of the agar cultures of S. 

 albufi, namely, pneumococci and hemolytic 

 streptococci. 



2. Bacteria which were not dis.sohed by 

 the most acti\-e soluble suiistance, but which 

 were depres.sed by the mycelium of the acti- 

 noniycete; these included various sarcinae 

 and B. megatherium. 



3. Bticteria which were not acted upon 

 either by the mycelium or by the acti\-e sub- 

 stance. These comprised the colon typhoid- 

 paratyphoid and the pyocyaneus groups. 

 When these bacteria were killed by heat or 

 were placed under conditions unfavorable to 



