xoMMNci.A'niM'; AM) ( ".iiMiirM, s^■s'^l•:Ms oi" classii'icatiox 



53 



111 liiiic, h()\V('\('r, llic iiciicric ii.iiur Acli- 

 noini/cis cniiu' to Ix' recognized lur itie MiKiei'- 

 oliir tiroiip III ;i('l iuoiiiN'cel es coneenied with 

 ihe causal i(Ui ol human and animal actino- 

 mycosis accompanied l)y tlie ronnation ot 

 >ii'aiiuh>s. 



( irachiall.w tlie position of tlie actino- 

 mycotos as a l)iological system hecaine recojj;- 

 ni/.ed. Before pr()eeedin<i; witli tlie cluirae- 

 teri/ation of the actinomycetes as an 

 independent j>;r()up of niieroorj>;anisms and 

 with their proper classification into ^eii(>ra 

 and .species, we must consider their relation- 

 ship to two other groups of microorganisms, 

 namely, the true bacteria and the true fungi. 



Kolation of Aotinoiiiycetes to Bacteria 

 and Fungi 



F. Cohn considered his streptothrix as a 

 bacterial form. Almcjuist (181)0) also looked 

 upon this group of organisms as belonging 

 to the bacteria, in spite of Brefeld's assertion 

 that they are closely related to the fila- 

 mentous fungi. Almquist himself isolated 

 in pvn-e cultnre three organisms, one as a 

 dust contaminant, another from water, and 

 a third from the body of a person who re- 

 cently had died from cerebrospinal meningi- 

 tis. All appeared to be forms that would now 

 be considered as members of the genus 

 Streptomyces, although the third form did 

 not produce any aerial mycelium. 



Since then, consideral)le discussion has 

 taken place concerning the relationship of 

 the actinomycetes to the bacteria, on the 

 one hand, and the fmigi, on the othcM'. The 

 information that has been gradually accunui- 

 lating tends to emphasize that actually the 

 actinomj^cetes are more closely related to the 

 true bacteria. 



Relationship to bacteria. The following 

 facts may be presented to substantiate this 

 relationship : 



1 . The diameters of the hyphae and spores 

 of actinomycetes (usually O.o-l.O m) :^1'p 

 similar to those of bacteria but not of fungi. 



'J. Many act iiioniyceles rc|)ro(liice l»y 

 fragmcnls or oidia that arc similar in size 

 and in shape to the rod sha|)cd and s|)lieri(^al 

 l)acteria. 



'.->. Ahuiy actinomycetes pioduce no tiue 

 aerial mycelium; their growth appears simi- 

 lar to that of certain pleomorpiiic bacteria, 

 especially to corynel)acteria. 



4. Many actinomycetes are acid-fast; 

 they I'esemble, botii in their morphology and 

 in tiieir physiology, the mycobacteria. Tliis 

 is true particularly of members of the genus 

 Nocardia. 



5. Nuclear staining, phase microscopy, 

 and \-ital staining with diachromes and 

 fluorochrom(>s show that actinomycetes pos- 

 sess nucleoids. N(j true mitosis could be dem- 

 onstrated, nor any nucleus b}^ means of the 

 Feulgen reaction. All these facts suggest the 

 close systematic relationship of the actino- 

 mycetes to the bacteria. 



6. The chemical composition of the cells 

 points to the relationship of the actinomy- 

 cetes to the bacteria I'ather than to the fungi. 

 When the spores are liV)erated as a I'esult of 

 the break-up of the sporophores, the empty 

 shells become A'isible; the cell wall is soluble 

 in 10 per cent KOH solution and in anti- 

 formin. When the cells of Streptomijces were 

 treated with lysozyme, the cell walls were 

 found to be mucoid in nature and were 

 hydrolyzed to glucosamine. 



7. Cells of actinomycetes do not contain 

 chitin oi- cellulose*, characteristic of true 

 fungi. 



8. Acthiomycetes, like true bacteria, are 

 procaryotes, whereas fungi are eucaryotes. 



9. The phenomena of lysis and phage 

 sensitivity among the actinomycetes point 

 further to their relationship to the bacteria 

 i-ather than to the fungi. 



10. I'inally, the recent evidence concern- 

 ing the sensitivity of the actinomycetes to 

 antibiotics ])laces them definitely with the 

 l)acteria and not with the true fungi. 



These facts fully justify the conclusion 



