Factors Influencing Anaerobiosis. 



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Factors influencing anaerobiosis with special reference to the 

 use of fresh tissue. 



By Frederick L. Gates and Peter K. Olitsky. 



[From the Laboratories of the Rockefeller Institute for Medical 

 Research, New York City.] 



With methylene blue as an indicator, we have studied the 

 influence of certain elements in promoting or in hindering the 

 development of anaerobic conditions in tissue cultures. 



As a result of our experiments, we have come to the following 

 conclusions: 



Liquid paraffin oil, used extensively as a seal for anaerobic 

 cultures and in gas analysis, has very little value in inhibiting the 

 access of oxygen. Solid vaseline, on the other hand, forms an 

 effective oxygen-resisting seal. The difference is due to the 

 physical states of the substances at incubator temperature. 



Fresh kidney tissue is an active reducing agent and quickly 

 decolorizes methylene blue in its vicinity. The reducing effect of 

 fresh kidney tissue is relative to the amount used. As a reducing 

 agent, at least 0.6 gm. per tube is required for the establishment of 

 an adequate oxygen free zone. 



Culture media may be classified as reducing or non-reducing. 

 Those containing dextrose or peptone in a faintly alkaline solution 

 belong to the former class. Ascitic fluid and dilute serum belong 

 to the latter class, for their content of reducing substances is 

 practically insignificant. For the prompt establishment of strictly 

 anaerobic conditions these media require the addition of reducing 

 substances such as dextrose, peptone, or kidney tissue aided by an 

 effective seal or an anaerobic jar. 



Semisolid media effectively inhibit the penetration of oxygen 

 to the depths of the tube, but they likewise limit the diffusion of 

 reducing substances and presumably of nutrient substances from 

 imbedded kidney tissue. 



The length of the column of medium is of minor importance 

 under a vaseline seal. 



