916 



Jaffe, M. J., and Linda Thoma. 1975. 



The effects of gibberellic acid and two plant growth retardants on the beat 

 of the clam heart. Comp. Biochem. Physiol. 51C(2): 309-311. 



Heart beat of M era en aria mercenaria was inhibited by 25% with 30 yM 

 gibberellic acid (GA) , 160 yM N-dimethylamino succinamic acid (B-9) , 7 yM 

 (2-chloroethyl) trimethyl-ammonium chloride (CCC) , and 2 nM acetylcholine 

 chloride (ACh) . CCC is a quaternary ammonium compound, B-9 a tertiary 

 ammonium compound, and GA has no nitrogen. Frequency of beat was more 

 sensitive to most treatments than was amplitude. Whatever the precise 

 mode of action of these compounds, it is probable that they can affect the 

 ACh system in clam ventricle at physiological concentrations. GA probably 

 is a natural product of microflora on which the clam feeds, but clams may 

 also be exposed to runoff from agricultural land, which might subject them 

 to effects from growth retardants. It is interesting that compounds which 

 affect growth and the ACh system in plants are also capable of affecting an 

 animal organ that is sensitive to ACh. - J.L.M. 



917 



Janoff, Aaron, and Eugenia Hawrylko. 1964. 



Lysosomal enzymes in invertebrate leucocytes. J. Cell. Comp. Physiol. 

 63(3) : 267-271. 



Lysosomes are subcellular granules or vacuoles delimited by a single 

 membrane and containing a wide spectrum of acid-hydrolases. The study 

 used Mercenaria mercenaria and Asterias forbesi to find out if lysosomal 

 enzymes exist in amoebocytes of coelomic fluid of invertebrates. In hard 

 clam the mantle-cavity fluid was examined. In leucocytes from 72 clams 

 the following units of enzyme were found per 100 yg of protein: acid- 

 phenolphthalein phosphatase 0.9-0.4, acid RNA-ase 2.0*0.4, beta glucuronidase 

 9.0±1.6. Acid-phenolphthalein-phosphatase activity was slight, acid-RNAase 

 activity very high, and beta-glucuronidase activity appreciable in quahog 

 leucocytes. Subcellular distribution of enzymes was not finally determined. 

 At least a partial association of hydrolases with the granule fraction of 

 leucocytes was noted. - J.L.M. 



918 



Jarvis, Norman D. 194 3. 



Principles and methods in the canning of fishery products. U.S. Fish Wildl . 

 Serv., Research Rept. 7, 366 p. 



Venus mercenaria is found from the New England states to the coast of Texas. 

 It is usually found below low tide and does not burrow deeply into the bot- 

 tom. They are abundant in the southern states and the most productive beds 

 are on the Gulf coast of Florida, in the vicinity of the Everglades. Shells 

 of Florida hard clams are much thicker and heavier, although meats are 

 little, if any, heavier than in the north. Individual clams in the shell in 

 the south may weigh as much as 2 pounds. Quahogs are taken bv hand tongs 

 and dredges of the same type used for oysters.. They are also" taken by 

 "treading" . Long-handled rakes are used in some sections of the Atlantic 

 coast, short rakes are used in treading, and ordinary shovels are used at 

 times. From clam beds to cannery is usually not more than a few miles. 

 The canning operation is described. Canned hard clams are often variable 

 in quality. Discoloration and "seaweed" flavor and odor sometimes appear. 

 These defects may be largely overcome by removing the dark body mass when 

 washing the meat, but this adds to the cost of packing and is not often done. 

 Two types of clam chowder are canned, "Manhattan", "Rhode Island", or "Coney 

 Island" chowder; and the "New England" variety. Soft clams or quahogs are 

 used, although quahogs are preferred by some packers, as the clam flavor is 

 stronger. Recipes are given. Burnham and Morrill are credited with estab- 

 lishing the first clam cannery in the United States at Pine Point, Maine 

 in 1878. - J.L.M. 



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