2178 



Moore, Carol A. 1979. 



Ultrastructure of the cytoskeleton in the amebocytes of Mercenaria mercenaria. 

 J. Cell Biol. 83(2) Part 2: 315a (abstract M11723) . 



Amebocytes, initially rounded, attached by lamellipodia and filopodia. When 

 fully spread, cells exhibited an extensive system of cytoplasmic fibers de- 

 lineated into 3 zones: a perinuclear (50-65% spread cell width), a transition 

 (25-35% spread cell width), and a marginal (10-15% spread cell width) zone. 

 During cell spreading, disperse perinuclear cytoplasmic fibers were reorgan- 

 ized into: 1) numerous parallel bundles of filaments radiating outward from 

 the nuclear area; these bundles seemed to coincide with the movement of 

 organelles as seen with phase optics; 2) a network of filaments in which 

 organelles appear suspended. A ring of filament bundles often confined 

 organelles to the perinuclear zone and delimited it from the transition zone. 

 Filament bundles in the transition zone were less abundant, with a more ran- 

 dom arrangement. Some bundles originating in this zone traversed the outer- 

 most marginal zone where they meshed with additional bundles and microtubules 

 to form the core of filopodia; occasional bundles from the perinuclear area 

 were involved. The narrow marginal zone, as viewed by S.E.M. and time-lapse 

 cinematography, revealed extensive membrane ruffling, particularly where long 

 filopodia were absent. These ruffled edges consisted of a meshwork of short 

 fibers in a dense cytoplasmic matrix. It is suggested that the intracellular 

 fiber systems are responsible for support as well as the dynamic mobility of 

 the amebocyte and its organelles. - modified author's abstract - J.L.M. 



2179 



Moore, C. A., and S. R. Gelder. 1979. 



The relationship between phagocytized material and the "blunt" granules in 

 hemocytes of Mercenaria mercenaria. Am. Zool. 19(777): 1007 (abstract). 



Vital dyes and f luorescently labeled materials were used. Hemocytes were 

 syringed from the posterior adductor muscle, settled on cover glasses and 

 stained (neutral red followed by Janus green B; acridine orange) or allowed 

 to phagocytize Isochrysis galhana or Congo red stained yeast. Cells were 

 observed under phase contrast and epif luorescence illumination (violet-blue 

 light). Vital staining revealed some blunt granules (70%) to be stained with 

 neutral red/acridine orange while others took up Janus green B; some granules 

 were seen to contain acridine orange particles. After hemocytes phagocytized 

 Isochrysis, the algae fluorescent emission shifted from red to green-yellow. 

 Blunt granules, previously non-fluorescent, were observed to emit a green- 

 yellow fluorescence. Phagocytized Congo red stained yeast cells did not 

 yield similar results. This work suggests that the blunt granules receive 

 degraded material from the phagosome and may serve as a mechanism for con- 

 tainment of phagocytized materials. - J.L.M. 



2180 



Murawski, Steven A., and Fredric M. Serchuk. 1980. 



Clams and scallops of the northeast coast. Underwater Nat. 12(4): 25-33. 



Early records appear to show that the Indians used an increasing proportion 

 of bay scallops, and relied less on the hard clam, Mercenaria mercenaria. 

 This paper deals principally, however, with sea scallops, surf clam, and 

 ocean quahog. - J.L.M. 



2181 



Nakahara, Motokazu.and Ford A. Cross. 197 8. 



Transfer of cobalt-60 from phytoplankton to the clam (Mercenaria mercenaria) . 

 Bull. Japanese Soc. Sci. Fish. 44(5): 419-425. 



The transfer of cobalt-60 from phytoplankton (primary producer) to clams 

 (primary consumer) was investigated to obtain additional information about 

 the movement of cobalt-60 in the marine ecosystem. Retention of cobalt-60 

 in clams after feeding radioactive phytoplankton varies with size of clam 



606 



