364 Marine Microbiology 



increased requirement for cations may be a reflection of a marine 

 environment. 



SUMMARY 



There can be no doubt that phages active against marine 

 bacteria do exist in sea water. Such phages may readily be iso- 

 lated, provided that due attention is paid to such factors as the 

 choice of host bacterial strains, media and temperature of in- 

 cubation, and that a sufficiently large volume of sea water is 

 examined. The quantitative occurrence in sea water of phages 

 active against particular bacterial stiains may even be determined. 

 Little is known, however, of the ecology of such phages, nor their 

 characteristics, although indications liave been obtained that they 

 may differ from terrestrial bacteria in respect to their temperature 

 relations, such as thermal inactivation and range of temperature 

 for multiplication, and ionic relations, such as ability to survive 

 in sea water and special requirements of monovalent and divalent 

 cations, particularly Na^ and Mg"^^, for lysis. 



REFERENCES 



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;. Gen. Physiol, 32:579-594, 1949. 



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3. Amos, H.: Stabilizing effect of amino acids on bacteriophage Tlr+. 



Proc. Soc. Exptl. Biol. Med., 86:832-834, 1954. 



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