of dopamine-^H were converted in pedal than in cerebral or visceral ganglia. 

 Measurements of dopamine turnover in isolated pedal ganglia, and the time 

 course of ganglionic dopamine synthesized in the clam, suggest that dopamine 

 is not actively metabolized in Mevcenaria ganglia. - J.L.M. 



1762 



Sykes, James E., and John R. Hall. 1971. 



Comparative distribution of molluscs in dredged and undredged portions of an 

 estuary, with a systematic list of species. U.S. Dept. Interior, Bu. Comm. 

 Fish., Fish. Bull. 68(2): 299-306. (Also issued as a separate, dated 1970.) 



Mollusk species and numbers of organisms were much less numerous in soft 

 sediments of canals than in sandy sediments in undredged parts of Boca Ciega 

 Bay, Fia. Living specimens of 5 species, including Mercenaria campeehiensis , 

 were found in 14 samples from canals, which had sediments with 85% silt a/id 

 clay. In 93 samples from undredged areas 156 species were taken, also 

 including M. campeehiensis . Natural bottom averaged 91% sand and shell and 

 yielded 5,631 live mollusks. Channel stations yielded only 16 living 

 mollusks. Soft sediment was the principal factor limiting abundance and 

 diversity of mollusks in bayfill canals. Such sediments were as thick as 

 4 m in waterways dredged 15 yrs earlier. - J.L.M. 



17 63 



Syverton, J., W. S. Scherer, and T. M. Elwood. 1954. 



Studies on the propagation in vitro of poliomyelitis viruses. V. The 

 application of strain HeLa human epithelial cells for isolation and typing. 

 J. Lab. Clin. Med. 43(2): 286-302. 



Mercenaria (Venus) mercenaria is not mentioned. - M.W.5. 



1764 



Szent-Gyorgyi, Albert. 1958. 



Motion, energy transmission, and the cellular matrix. In Perspectives in 

 Marine Biology. A. A. Buzzati-Traverso (ed.) . Univ. Calif. Press, Berkeley: 

 233-238. 



This chapter contains no direct reference to any species, but it does explain 

 why the author chose to base his scientific research on motion and its organ 

 muscle, which led him to work on mollusks, including Venus (Mercenaria) 

 mercenaria. Many of his publications are abstracted in this bibliography. 

 Motion is generated in muscle by a complex protein, actomyosin, composed of 

 two single proteins, actin and myosin. This complex interacts with ATP, a 

 nucleotide, and ions. Myosin is built of rod-shaped molecules, probably about 

 1,200 A long and 15-20 A wide. Actin is built of globular molecules which can 

 associate to long strings. The relation of actin to myosin is decided by the 

 ions present, which, with their charges,, dominate electric attraction and 

 repulsions between the 2 proteins. The nucleotide ATP has 3 parts: a 

 heterocyclic purine base, a pentose, and a chain of 3 phosphate groups joined 

 by P-O-P links. About 10,000 calories of free energy have to be invested to 

 establish such a link. By splitting a link, an equal amount of energy is 

 released. In muscle contraction the last of these P-O-P links is split, to 

 give the energy that moves bodies of animals. Early work suggested that myosin 

 molecules formed a rod, which contracted by folding. More recent studies 

 showed that the myosin molecule is built of subunits, which were called 

 "meromyosins" . A myosin molecule of MW 420,000 has 3 such subunits, one 

 thick, and with 2 slender units in line with it, one at each end. The work 

 seemed to be done by the slender meromyosins, but the energy of ATP was 

 released by the thicker ones, and somehow had to get from thick to slender 

 subunits. Meromyosins are built of a large number of MW 4,500 gram subunits 

 called "protomyosins" held together by weak secondary forces. It is probable 

 that contraction is not a folding, but some rearrangement of protomyosins. 

 The P-O-P bond has only a potential, which has to be exchanged for energy when 

 it goes into biological action. Muscular contraction is essentially the 

 reversal of what happens in photosynthesis. - J.L.M. 



487 



