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Development of the surf clam (Spisula solidissima) following exposure of gametes, embryos, and larvae to silver (1984)

Eyster, Linda S. ; Morse, M. Patricia

Springer

Archives of environmental contamination and toxicology 13 (1984), S. 641-646

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ISSN: 1432-0703

Source: Springer Online Journal Archives 1860-2000

Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine

Notes: Abstract The gametes, embryos, and early larvae of the surf clamSpisula solidissima were exposed to silver at concentrations up to 65 μg/L. All experiments were conducted at 20°C and 30‰ S, and lasted up to 48 hr after fertilization. Forty-five minute exposures of eggs to 16 μg/L or more silver just prior to fertilization in non-silver seawater lead to production of abnormal larvae. Simultaneous exposures of eggs and sperm to silver concentrations up to 21 μg/L for 45 min did not prevent fertilization but did produce abnormal larvae at silver concentrations greater than 6 μg/L. Postfertilization treatments of zygotes, embryos, and larvae lead to fewer abnormalities than prefertilization or fertilization treatments of comparable exposure length and concentration. The greatest numbers of abnormalities and mortalities were observed in continuous exposures, from gametes through fertilization to 48 hr postfertilization. Variability in % normal development was greater in high than in low silver concentrations.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01056344

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Podocytes in bivalve molluscs: Morphological evidence for ultrafiltration (1985)

Meyhöfer, Edgar ; Morse, M. Patricia ; Robinson, William E.

Springer

Journal of comparative physiology 156 (1985), S. 151-161

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ISSN: 1432-136X

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary In representatives from a survey of three major taxa of bivalves the pericardial glands were found in two distinct positions. In protobranches (Acila castrensis) and filibranch bivalves (Glycymeris subobsoleta, Chlamys hastata, Pecten caurinus, Placopecten magellanicus, Mytilus edulis andMytilus californianus) the pericardial glands are located on the auricular surface. In heterodonts (Mercenaria mercenaria, Clinocardium nuttallii andMya arenaria) the pericardial glands are found in an anterodorsal position to the pericardial cavity. The sites of ultrafiltration are described. They consist of podocytes with basally extending pedicels forming an interdigitating network apposed to a basal lamina. Other characteristics of this ultrafiltration barrier described are anionic sites on the basal lamina and presence of substructural components within the ultrafiltration slits between pedicels. The pathway for the ultrafiltrate in protobranchs and filibranchs is from the hemocoel through the basal lamina, through the ultrafiltration slits of the pedicel network, into the urinary spaces between the podocyte cell bodies and into the pericardial cavity. The pathway for the ultrafiltrate in heterodonts is from the hemocoel through the basal lamina, through the ultrafiltration slits of the pedicel network, into urinary spaces between the podocyte cell bodies, into the lumen of the pericardial gland tubules and into the pericardial cavity. All podocyte cells have electron dense granules, Golgi apparatus and vacuoles associated with their cytoplasm. Heterodont species have microvilli on the cell surfaces of the podocytes apposed to urinary spaces. In all cases the morphological sites of ultrafiltration were associated with the pericardial glands of the heart-pericardial complex.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00695769

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Functional adaptations of the digestive system of the carnivorous mollusc Pleurobranchaea californica MacFarland, 1966 (1984)

Morse, M. Patricia

New York, NY : Wiley-Blackwell

Journal of Morphology 180 (1984), S. 253-269

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ISSN: 0362-2525

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: The opisthobranch mollusc Pleurobranchaea californica feeds on whole organisms and the functional morphology of the digestive system reflects this behavior. By a rhythmic behavior involving well-developed extrinsic buccal muscles and hemocoelic fluid, the buccal mass is protracted to the tip of the everted oral tube. Here a series of repeated protractions and retractions of the intrinsic buccal muscles associated with the flat radular ribbon and jaws draws the prey into the buccal cavity and conveys it to the dorsal esophagus, where by peristaltic action it is passed to the expansible crop for storage. Prey entering the buccal cavity is mixed with acid from a large single gland and secretion from the paired salivary glands. Prey is retained in the crop over long periods of time while it is slowly broken down and passed via the stomach into the digestive glands. Special modifications that allow flexibility of the digestive organs include elongated salivary gland ducts with propulsive bulbs, long flexible nerve cords connecting the ganglia, a long, large muscular duct for storage of the acid secretion, large jaws for muscle attachment and grasping the prey, and a broad radular ribbon with many teeth that acts as a conveyor belt to move food. Additional modifications for handling whole prey include a buccal membrane that aids in maintaining hemocoelic fluid pressure, the extensive acid gland for immobilization of prey, and the expansible crop for storage of food.

Additional Material: 14 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jmor.1051800308

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