Proteolysis and Nitrate Reduction in Sea Water 413 



Erwinia and to Chromohactereae, and a lesser extent to Vibrio 

 (30%), Achromobacter, Pseuclornonas and Acinetobacter. 



The role of these microorganisms in the processes of prote- 

 olysis and nitrate reduction is of topmost importance. 



These observations confirm previous investigations on the 

 microflora of fish and shellfish, on bacteria pathogenic for marine 

 animals and on bacteria isolated from sea food by us and co- 

 workers (2, 3, 4, 5), by Gianelli (7) in Italy, and by Fischer (6) 

 from fishes of the Baltic Sea, These data show that the intestinal 

 microflora of shellfish is predominantly represented by Pseu- 

 domonadaceae and more precisely by Achromobacter, Erwinia 

 and Flavobacterium. These bacteria are the main agents responsi- 

 ble for proteolysis and decomposition of sea food. 



The Psetidomonadaceae are also responsible for diseases of 

 fishes and shellfish. All these data emphasize the importance of 

 this microflora and its economical and practical incidences to 

 protein degration and nitrate reduction. Many of these bacteria 

 are very active on coagulated serum and some amino acids. 



CONCLUSIONS 



Present work demonstrates the very important role of Pseu- 

 domonadaceae and Vibrio (all of them halophilic) not only in 

 the marine nitrogen cycle, but also in the aerobic processes of 

 proteolysis and nitrate reduction in marine environment. Nitrite 

 is metabolized by other bacterial species which are able to re- 

 duce it further to ammonia and/or free nitrogen. Many Pseu- 

 domonadaceae, concurrently with other bacterial groups, are also 

 active in these further steps of denitrification. 



Our observations have some pathologic and hygienic interest, 

 due to the fact that a small number of investigations have already 

 demonstrated the role of these bacteria in the diseases of marine 

 animals and plants, and also due to the fact that these micro- 

 organisms are the agents of human intoxications and presumably 

 of human diseases. Actually, some observations have shown the 

 role of Achromobactereae and other Pseudomonadaceae in di- 

 gestive and pulmonary diseases. 



