'SEXUALITY IN BACTERIA TI3 



G; SEXUALITY IN STREPTOMYCES AND ACTINOMYCES 



(17, 24, 27) 



The descriptions of these genera are taken ahnost exckisively from the 

 admirable descriptions of- Kheneberger-Nobel (1947a) and Morris (1951a) 

 respectively. 



The nuclear material ni die primary mycelium of streptomyces is in a 

 form which resembles the chromosome complexes of young cultures of 

 eubacteria. The secondary mycelium, from which the spores arise, contains 

 rod-shaped, fusion nuclei. The sexual process which brings about this trans- 

 formation is unhkc any of those which have so far been described, in that a 

 special, sexual organ is produced for the purpose. Branches arise from the 

 primary mycelium, which may be much ramified or tightly curled at the 

 ends. These become entangled with other, similar branches, forming " nests " 

 of filamentous cells, within which the initial cells of the secondary mycehum 

 arise. The initial cells are spherical or oval and contain a central nucleus. 

 They germinate to form the secondary mycelium, with its rod-shaped fusion 

 nuclei. 



Spores are formed by the fragmentation of the fusion nuclei within special, 

 aerial hypha; arising from the secondary mycelium. The chromatinic material 

 at first forms paired chromosomes which are transtormed into the simple 

 spherical spore nuclei. 



The primary mycelium, which arises trom the germination of the spores, 

 is apparently haploid, like the spores themselves, and the secondary mycelium, 

 diploid, but the details of the intervening sexual process, which presumably 

 occurs in the mycelial " nests," are not described. 



The nuclear material of the primary mycehum ot the anaerobic actinomyces 

 is also similar to that of vegetative eubacteria, but in this case the branching 

 of the filaments is impermanent, and the mycelium less complex than in the 

 streptomyces. The initial cells of the secondary phase arise by the conjugation 

 of bacillary units from the primary mycelium, and germinate to produce an 

 apparently diploid mycelium, which is branched but non-septate and coenocytic. 

 The spores arise singly on short branches, and the reduction process which 



