598 Marine Microbiology 



tiied to determine the necessary nutrients for optimal growth 

 and chitinase production. Table 1 shows the relative effects ob- 

 tained by adding 0.1 per cent yeast extract (Difco) and 0.1 per 

 cent peptone (Difco) to chitin-sea water agar (0.1% chitin, 1.5% 

 agar). Incubation was at room temperature for twenty three days. 



Oxygen Tension 



Several experiments were run to determine oxygen tension 

 preferences of marine chitinoclasts. Pour plates with sea water 

 and with pelagic zooplankton inocula were incubated aerobically 

 and anaerobicaUy. Lack of oxygen inhibited growth and chitino- 

 clastic activity. Another approach made was to inoculate semi- 

 solid chitin agar tubes with natural inocula. In all cases, growth 

 and chitinoclastic activity were greater with aerobic conditions. 



Incubation 



Extended incubation periods at 22-25 C. were found neces- 

 sary for the development of chitinoclasts on chitin-yeast extract 

 agar. The maximum number of colonies developed on the plates 

 before clear zones around the colonies became evident under a 



ENTIRE PLATEG 

 CLEARtL. 



HLATES 75% 

 CLEARED 



SPREADING OF 

 CLEAR ZONES 



LOCALIZED 

 CLEAR ZONES 



CLEAR ZONES 

 DETECTABLE 



NO CLEARING 



TIME IN DAYS 



Fig. 2. Rate of chitin degradation by pure cultures of marine chitinoclastic 



bacteria. 



