1265 



Meigs, E. B. 1915. 



The ash of clam muscle in relation to its osmotic properties. J. Biol. 

 Chem. 22: 493. 



Data cited by Vinogradov (1953) , abstracted elsewhere in this bibliography. 

 - J.L.M. 



1266 



Melson, Gail L., and Robert W. Cowgill. 1976. 



Comparison of the muscle protein paramyosin from different molluscan species. 

 Comp. Biochem. Physiol. 55B(4): 503-510. 



Paramyosin is a contractile protein consisting of 2 intertwined a-helical 

 chains. It was isolated and purified from Mercenaria mercenaria and 3 other 

 mollusks. Yields of 14 to 22.5 mg of purified paramyosin/g wet weight whole 

 adductor muscle were obtained from hard clam by 3 different extraction 

 methods. Estimated molecular weights ranged from 200,000 to 207,000 Daltons. 

 Paramyosin appeared to be partially degraded unless proteolytic attack during 

 the isolation procedure was prevented. Fluorescence was characteristic of 

 emission from tyrosyl residues. Apparently the other fluorescent amino acid 

 tryptophan is absent. Relative quantum yield of fluorescence (R tyr ) and 

 absorbance at 276 nm for tyrosyl residues on paramyosins were: pH 2 , 0.67; pH 

 7, 0.40, pH 2/pH 7, 1.67; A276 r 0.30. This shows that paramyosin is helical 

 and displays fluorescence quenching at neutral pH. Amino acids, expressed as 

 mole percent, were: glutamic acid 21.4, leucine 12.4, aspartic acid 13.3, 

 alanine 12.0, arginine 10.7, lysine 7.0, serine 4.8, and lesser amounts of 

 8 others. Solubility of paramyosin from hard clam decreases markedly at low 

 ionic strength at neutral pH. It was denatured by guanidine-HCl in multiple 

 stages. When exposed to proteolysis by pepsin and trypsin, paramyosin from 

 Mercenaria accumulated a resistant segment of 132,000 Daltons, suggesting 

 that regions of paramyosin vary in stability, and that these variations may 

 be of physiological significance in function of the molecule. - J.L.M. 



1267 



Menzel, R. Winston (edj . 1956. 



Annotated check-list of the marine fauna and flora of the St. George's Sound 

 - Apalachee Bay region, Florida Gulf coast. Fla. State Univ., Oceanogr. 

 Inst., Contrib. 61, 78 p. 



Compiled primarily for student use in a course. Mercenaria campechiensis is 

 included, but not M. mercenaria. Representative area is sand bars, grass 

 flats, shell, and mud areas. Substrate is sand-mud. Occurs throughout the 

 year. Salinity range 25 to 37°/°°. Abundance: common. - J.L.M. 



1268 



Menzel, R. W. 1960. 



Growth and mortality of northern hard clam in Florida waters. Assoc. SE 

 Biol., Bull. 7(2): 34-35 (abstract). 



Growth of laboratory-reared Mercenaria mercenaria from Milford, Conn, was 

 excellent, some reaching commercial size in 18 months. Growth was best in 

 fall and spring, less in winter, and almost ceased in summer, especially 

 during 2nd year. Mortality was very low when clams were protected from 

 predators, but soon reached 100% without protection. - J.L.M. 



354 



