^ll^■sl()l.()(;^■ 



ir 



tlu' t'olliiwiiiii Idinuihi : 



IIN-C— C=CH— C— XH,. 



II I II 



() () O 



I 

 C0H5 



T]u> imtiitioM of the various or<>;aiiisins 

 and [hv ct'lVn'ts of cortaiii specific cmiroii- 

 nuMital factoi's may be coiisidei-ed in fui'- 

 tluT detail. 



I none (19.")S") rei)oi-t(^d a iiiiili lexcl o\vi;-en 

 demand for N. (/ris(us grown on soylxvm 

 medium at 24 and 9() hours. \\'ith d(>ficient 

 aeration and in alkaline media, the sec- 

 ondary high le\'el oxygen demand inci'eased; 

 with an excess aeration the latter disap- 

 peared. Streptomycin inhibited the oxygen 

 uptake of young cells at abo\-e a certain 

 concentration ; this inhibiting action is some- 

 ^vhat pre\ented by the addition of 10 " M 

 .Mg and 10"' .1/ Mn. 



The carbon dioxide output of S. griscus 

 gave a maximum rate at 24 hours. The Qo_> 

 value and QCO2 curve were lower with my- 

 celium than with spore inoculation. The 

 R.Q. value uidicated minimum at 48 hours. 



Both young and old cells were inhibited 

 ]\v streptomycin, but the inhibitory action 

 was influenced by the relative concentra- 

 tions of streptomycin and an unknown fac- 

 tor in the medium. The 3'oung cells were 

 more sensitive than the old cells. There was 

 believed to exist a difference in the char- 

 acters (or the enzyme systems) of the young 

 and old cells. The carbon dioxide output 

 was inhibited by streptomycin much more 

 than the oxygen uptake. 



Fermentation processes of soybean me- 

 dium by two strains of S. griseus fell into 

 four pha.ses: (a) the amount of mycelium 

 increases, glucose consumption is slight, 

 oxygen demand is high, and streptomycin 

 production is very low; (b) the amount of 

 mycelium is almost constant or slightly in- 

 creases, glucose consumption is high, strep- 

 tomycin production increases, and oxygen 

 demand decreases markedly; (c) mycelium 



increases again and icaclies a niaximiHM he- 

 cause ol a secondai'X' geiniinat ion or growt h ; 

 (d) autolysis occurs, glucose is completely 

 consumed, and st i-eptomycin pi-oduction 

 reaches the maximum. In the casein me- 

 dium, the fei'inentation process falls into 2 

 j)hases, and the secondary germination or 

 gi'owth is not observed. 



The (^o.j values showcnl the same tendency 

 both in soybean and casein media. In the 

 lattei', th(> presence or absence of metal salts 

 did not influence the (Joj value, but it played 

 an impoiianl I'ole in streptomycin forma- 

 tion. 



CarI>on Nutrition 



Actinomycetes grow in nature on a wide 

 variety of substrates. The nutrition of ac- 

 tinomycetes can be considered on the basis 

 of the various essential elements reciuii'ed, 

 notably, carbon, nitrogen, and certain min- 

 erals, as well as sources of these elements. 

 These sources range fi'om complex organic 

 environments, such as drained peat bogs, 

 high organic soils, and composts of straw or 

 of stable manures, to fairly simple media, 

 such as poor sandy .soils and simple syn- 

 thetic substrates. 



Actinomycetes are able to utilize a great 

 variety of organic compounds as sources of 

 energy. These compounds include organic 

 acids, sugars, starches, hemicelluloses and 

 cellulose, proteins, polypeptides and amino 

 acids, nitrogenous bases, and numerous 

 other substances. Some actinomycetes can 

 also attack fats, hydrocarbons, benzene 

 ring compounds, and, to a more limited de- 

 gree, lignin, tannin, and rubber. There is 

 considerable selectivity in the utilization of 

 these substances by different kinds of actino- 

 mycetes. Some of the nutrients, like glucose, 

 maltose, dextrin, starch, glycerol, amino 

 acids, and proteins, are consumed \ery 

 readily; in fact, they are the best sources of 

 carbon. Sucrose, xylose, raffinose, and cer- 

 taui other sugars, sugar alcohols, and sugar 



