MIM'.KAI. MI.'I'AKOI.ISM AND IlKl'llCT <»l' SAI/I'S ()\ CHOWTH 



145 



inyeos cultures was studied. 'I'lic metals wei'e 

 lluMi added singly and in all possible e(tiu- 

 l)inati()ns at eoneenl rat ions of ;i parts pei' 

 niillion. (Ifowtli was usetl as the eiitefion of 

 (>tVeet, and the results wore analyzed statis- 

 tically. Iron and zinc \V(>ro h(>no(ieial foi- the 

 iirowth of all eii;;ht cultures iiucst i.<;ated. 

 Calcium was IxMu^licial for six of the eiji,ht ; 

 iS. larcndulac and N. aurcofaciens were ini- 

 art'ected. Manganese was effective foi' only 

 ^'. coclicolor. An iron-zinc intfM'action was 

 beneficial in all cases. 



Calcium was found to retard the onset 

 and rate of lysis of aS. Jradiac in concentra- 

 tions as low as 1.5 parts per million. It also 

 enhanced the utilization of glycine and glu- 

 tamic acid in the medium. Alohan observed 

 that increasing concentrations of calcium 

 chloride in the medium enhanced the utiliza- 

 tion of glutamic acid. Alagnesium could not 

 l)e replaced by manganese in the medium 

 and its omission resulted in almost no growth 

 of »S. Jradiac. The effect of copper on four 

 streptomyces cultures was investigated by 

 Heim ; growth of S. fradiae decreased 55 per 

 cent when copper was omitted, but there 

 was no effect on S. griseus, S. rimosus, or S. 

 lai'cndulac. 



Due to the specific effect of iron, Heim ct 

 al. analyzed for the presence of cytochromes. 

 In a sur\'ey of 13 cultures five were found to 

 contain only a b type cytochrome, and eight 

 contained both b and c types. It was sug- 

 gested that the importance of the cyto- 

 chromes as respiratory pigments and the 

 presence of iron in the molecule may explain, 

 at least in part, the importance of iron in the 

 metabolism of the streptomyces. 



Potassium, magnesium, zinc, iron, copper, 

 and calcium are thus shown to be recjuired 

 for most, if not all, of the phases of the 

 metabolism of actinomycetes. Certain met- 

 als, such as cobalt for vitamin B]2 produc- 

 tion and iron for the grisein molecule, are 

 required for incorporation into specific mole- 

 cules. A study of sodium recjuirement indi- 



cated a special effect of this elenienl on t he 

 dilTusion of streptomycin into the culture 

 medium of N. iiris( us. The presence of this 

 element does not ap|)eai' to be a general re- 

 (luirement for nutrition of actinomycetes. 

 -Manganese is not i-e(|uire(l generally for 

 growth or ant il)i()t ic product i(.)n ; in some 

 cases it was excn slightly inhibitory. 'I'ho 

 inhil)iting effect of aluminum ions was also 

 rei)()rted. This woukl appear to be not a 

 ([ualitativc effect but rather a tiuantitative 

 one, since Heim could not observe any in- 

 hibition due to its presence in a medium 

 treated with chromatographic alumina. 



The effective concentrations of various 

 metals in the nutrition of most actinomy- 

 cetes vary according to conditions under 

 which the organism is grown or according 

 to the specific effect re(iuired, such as anti- 

 biotic or A'itamin production. Metals which 

 exert a beneficial effect at some concentra- 

 tions may be inhil)itory at higher concentra- 

 tions. This is common with col)alt in vitamin 

 Bi2 production and iron in the formation of 

 some of the antibiotics. 



In a study of the formation of chlortetra- 

 cycline and bromtetracycline by different 

 mutants of S. aureofaciens, some were found 

 to be independent of the CI concentration 

 over a range of 0.02 to 10.0 stoichiometric 

 equivalents, whereas the formation of chlor- 

 tetracycline by other mutants depended on 

 the CI concentration over the above range. 



Gallicchio and Gottlieb (I<)58) studied the 

 effects of the microelements Zn, Fe, JVIn, Mo, 

 Co, Cu, B, and Ga and the macroelement, 

 INIg, on growth and chloramphenicol produc- 

 tion by S. venezuclae. Elimination of Zn or 

 Fe from the mixture added to a CaCOs- 

 treated synthetic medium resulted in the 

 suppression of chloramphenicol production. 

 Xo one mineral in the synthetic medium 

 supported production of the antibiotic, but 

 the addition of Zn with Fe had a favorable 

 effect. A larger concentration of Mg was re- 

 (piired for growth than for chloramphenicol 



