title: Morphological and cytoenzymatic characteristics of peripheral zone of lytic plaques induced by mycobacterial phages.
abstract: Morphology and cytoenzymatic characteristics were studied using potassium tellurite, of peripheral zones of lytic plaques in fast growing mycobacteria (ATCC 607, Redmond No 521, Penso S1P) exposed to various mycobacterial phages and slowly growing M. bovis BCG, H37RV 50 gamma INH resistant strains. The latter revealed on borders of lytic plaques a bright tellurite-negative zone of variable width, macroscopically undemonstrable in culture free from potassium tellurite. Microscopically only single mycobacteria of various shapes, whereas in the tellurite-positive zone typical arrangement of BCG rods in compact, strong acid-fast cords present also in the so-called grey zone contacting the tellurite-negative zone, were found. The said tellurite zonal phenomen is explained by abortive infection with phages under study, which results in killing the mycobacterial cells without phage multiplication. The microscopical examination of surface pellicles by thin section showed the phage abortive infection to form a much broader zone than demonstrable in macroscopical examination, since under the black pellicle containing reduced metallic tellurite another tellurite-negative layer is hidden. The quickly growing mycobacteria in the peripheral zones of lytic plaques were either fully tellurite-positive or showed on the inside of the plaque a very narrow, hardly visible tellurite-negative border, microscopically similar to M. bovis BCG and H37RV. The possible utilization of tellurite cytoenzymatic reaction in differential diagnostics both of mycobacteria and mycobacterial phages is discussed.
mesh_terms: D003470:Culture Media; D009160:Mycobacteriophages; D009161:Mycobacterium / Q000254:growth & development* / Q000378:metabolism; D009163:Mycobacterium bovis / Q000254:growth & development / Q000378:metabolism; D013691:Tellurium / Q000378:metabolism
chemical_list: D003470:Culture Media; C026899:potassium tellurate(IV); D013691:Tellurium