2050 



Yagi, N., M. H. Ito, H. Nakajiraa, T. Izumi, and I. Matsubara. 1977. 



Return of myosin heads to thick filaments after muscle contraction. Science 

 197 (4304) : 685-687. 



This paper deals with Rana catesbeiana, but may have a bearing on similar 

 research on muscle activity of hard clam, abstracted elsewhere in this 

 bibliography. Heads of myosin molecules play a major role in producing 

 contractile force of muscle. Heads move to the vicinity of thin filaments 

 to react with actin during contraction. Return to the thick filaments has 

 2 stages: rapid return of most myosin heads, then slow return of the rest. 



- J.L.M. 



2051 



Yentsch, C. S., F. P. White, and W. S. Richardson. 1969. 



Is a closed system for growing shellfish a realistic approach? In Proc . 

 Conf. Shellf. Culture, Nassau-Suffolk Regional Marine Resources Council, 

 Hauppauge, N.Y.: 7-10. 



The diatom Phaeodactylum tvicovnutum has been fed to adult Mevcenavia 

 mevcenavia in a closed system. The diatom culture had a volume of about 

 1/2 m3 and about 450 clams were kept in very crowded conditions in 200 1 

 of sea water. In Florida massive growth of phytoplankton was obtained in 

 one week. A portion of the culture was poured over clams, which fed until 

 water was visually free of algae in 6-10 hrs . Clams were kept with no 

 mortality for 5 mo. Fecal matter was removed periodically, and fresh water 

 was added to regulate salinity. The system was easily managed and could be 

 expanded. It was concluded that the closed system is a realistic approach. 



- J.L.M. 



2052 



Yeung, A., and R. W. Cowgill. 1976. 



Structural difference between a-paramyosin and 3-paramyosin of Mevcenavia 

 mevcenavia. Biochemistry 15(21): 4654-4659. 



Previous studies of a-paramyosin have been hampered by very low yields when 

 the protein was extracted by ethanol denaturation. A modification of the 

 procedure for sodium dodecyl sulphate gel electrophoresis permitted 

 separation of a-paramyosin (207,000 daltons) and 8-paramyosin (200,000 

 daltons). - J.L.M. and M.W.S. 



2053 



Yevich, Paul P., and Marcia M. Berry (sic). 1969. 



Ovarian tumors in the quahog Mevcenavia mevcenavia. J. Invert. Pathol. 14(2): 

 266-267. 



Earlier reviews of occurrence of tumors in invertebrates included no reports 

 of tumors in Mevcenavia mevcenavia. In routine histopathologic examination of 

 1,300 hard clams the authors found 3 cases of neoplasia in ovaries. No 

 unusual gross morphological anomalies were seen. Histology of the tumors is 

 described. In one animal, kidney tissue had been invaded. There was no 

 apparent relationship between incidence of tumors and water quality. 

 (Abstracter's note: the junior author's name is spelled Berry in the original 

 paper, but elsewhere, several times, M. M. Barry appears in association with 

 the name Yevich.) - J.L.M. 



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