329 



Cheng, T. C, and G. E. Rodrick. 1975. 



Release of lysosomal enzymes from hemolymph cells of Mercenaria mercenaria. 

 Trans. Am. Micr. Soc. 94(3): 435 (abstract). 



Lysozyme is released from hemolymph cells of M. mercenaria into the serum 

 during phagocytosis. The amount of enzyme released increases as phagocytic 

 challenge is increased, but reaches a maximum. Release of lysozyme is 

 concurrent with phagocytosis, and not a delayed event. Lack of release of 

 lactate dehydrogenase, a nonlysosomal enzyme, suggests that cell damage is 

 not necessary for enzyme release. g-glucuronidase is also released from 

 phagocytizing hemolymph cells. Acid and alkaline phosphatases also are 

 released, but do not occur in appreciable amounts in serum. These results 

 support the concept that release of lysosomal enzymes may play an important 

 role in internal defense by mollusks against invading microorganisms and 

 perhaps also against other nonself materials. - J.L.M. 



330 



Cheng, Thomas C ., and Gary E. Rodrick. 1975. 



Lysosomal and other enzymes in the hemolymph of Crassostrea virginiaa and 

 Mercenaria mercenaria. Comp. Biochem. Physiol. 52 (3B) : 443-447. 



Activities of lysozyme, acid and alkaline phosphatases, 6-glucuronidase, 

 amylase, lipase, glutamic-oxalacetic transaminase, and glutamic-pyruvic 

 transaminase were assayed in whole hemolymph, 4,000 g pellets, and 

 supernatants of Mercenaria mercenaria. All enzymes except amylase were 

 present in whole hemolymph and fractions. Amylase was found in Crassostrea 

 virginiaa , probably from the crystalline style. Lysosomal enzymes in 

 molluscan serum probably had been released from certain hemolymph cells. 

 They may play a role in destroying certain invading organisms. - modified 

 authors' abstract - J.L.M. 



331 



Cheng, Thomas C, Ann Cali, and David A. Foley. 1974. 



Cellular reactions in marine pelecypods as a factor influencing endosymbioses . 

 In Symbiosis in the Sea. Winona B. Vernberg (ed) . Univ. S.C. Press, 

 Columbia, p. 61-91. 



Hemolymph cells of Mercenaria mercenaria are much more uniform in size (20-30 

 y greatest diam) than those of Crassostrea virginiaa. Two types have been 

 recognized on basis of structure: granulocytes, in which granules are limited 

 to the endoplasm in the spread condition but uniformly distributed through 

 the cytoplasm in freshly drawn cells; and fibrocytes, very similar to those 

 of C. virginiaa , as described by Foley and Cheng (1972) in a paper abstracted 

 elsewhere in this bibliography. The granulocyte is the phagocytic cell. 

 Some evidence was obtained that bacteria were somehow altered chemically 

 after they were phagocytized. Granulocytes of M. mercenaria , like those of 

 C. .virginiaa , are extremely efficient in recognizing "self" from "nonself", 

 and foreign materials small enough to be phagocytized are readily arrested 

 by this mechanism. Most organisms phagocytized are eliminated or degraded 

 within the granulocyte, but some apparently survive. Microbial and other 

 small symbionts do occur in mollusks. For example, Minchinia nelsoni is 

 intercellular, and unless it becomes altered in some way, is recognized as 

 "self" and is sustained within the body of the mollusk. The only known 

 successful intracellular symbionts of marine mollusks are certain telosporean 

 protozoa-like Nematopsis , a haplosporean, and microsporidians , which occur 

 within phagocytes, or within cells of the gills, digestive tract or 

 nephridium. The nephridium is a primary site for deposition of foreign 

 materials introduced into the bodies of certain mollusks, and it could be 

 reasoned that protozoan parasites found in the nephridium have been carried 

 there by phagocytes. - J.L.M. 



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