Gill epithelial cell nuclear virus disease is prevalent and widespread in Mya arenaria clams of Chesapeake Bay, USA

2021 ◽  
Author(s):  
CF Dungan ◽  
EC Peters
Keyword(s):  
Epithelial Cell ◽  
Chesapeake Bay ◽  
Virus Disease ◽  
Mya Arenaria

Microbiological Studies of Chesapeake Bay Soft-shell Clams (Mya arenaria)

1990 ◽  
Vol 53 (12) ◽  
pp. 1052-1057 ◽  
Author(s):  
TUU-JYI CHAI ◽  
TZYY-JAN HAN ◽  
RALPH R. COCKEY ◽  
PATRICIA C. HENRY
Keyword(s):  
Chesapeake Bay ◽  
Microbiological Quality ◽  
Total Coliform ◽  
Mya Arenaria ◽  
Fecal Coliforms ◽  
Plate Count ◽  
Geometric Means ◽  
Standard Plate Count ◽  
Soft Shell ◽  
Standard Plate

A total of 472 samples of soft-shell clams (Mya arenaria), collected from three major clam harvest areas in the Chesapeake Bay and dockside check stations, was analyzed for standard plate count (SPC), total coliforms, fecal coliforms, Escherichia coli, and coliphages. SPC increased during the summer season. SPC geometric means of 2.6 × 104, 6.9 × 104, and 7.2 × 104/g, respectively, were found in three major harvest areas. Fecal coliforms remained relatively stable with geometric means of 30, 54, and 62/100 g. As seasonal temperatures increased, the total coliform geometric means declined slightly ranging from 1,500 to 6,300/100 g. E. coli means were low (< 27/100 g). The occurrence and levels of male-specific coliphages were also low and did not correlate with bacteriological quality. No significant microbiological quality difference was found between soft-shell clams sampled from harvest waters and check stations. Results indicate that the microbiological quality of soft-shell clams either at harvest or check stations was satisfactory.

scholarly journals Habitat complexity and benthic predator-prey interactions in Chesapeake Bay

2017 ◽  
Author(s):  
Cassandra N. Glaspie ◽  
Rochelle D. Seitz
Keyword(s):  
Chesapeake Bay ◽  
Habitat Complexity ◽  
Age Distribution ◽  
Oyster Shell ◽  
Mercenaria Mercenaria ◽  
Mya Arenaria ◽  
Hard Clam ◽  
Population Declines ◽  
Predator Prey ◽  
Mesocosm Experiments

ABSTRACTIn Chesapeake Bay, the soft-shell clam Mya arenaria (thin-shelled, deep-burrowing) exhibits population declines when predators are active and persists at low densities. In contrast, the hard clam Mercenaria mercenaria (thick-shelled, shallow-burrowing) has a stable population and age distribution. We examined the potential for habitat and predators to control densities and distributions of bivalves in a field caging experiment (Mya only) and laboratory mesocosm experiments (both species). In the field, clams exposed to predators experienced 76.3% greater mortality as compared to caged individuals, and blue crabs were likely responsible for most of the mortality of juvenile Mya. In mesocosm experiments, Mya had lower survival in sand and seagrass than in shell hash or oyster shell habitats. However, crabs often missed one or more prey in seagrass, shell, and oyster shell habitats. Predator search times and encounter rates declined when prey were at low densities, likely due to the added cost of inefficient foraging; however, this effect was more pronounced for Mya than for Mercenaria. Mercenaria had higher survival than Mya in mesocosm experiments, likely because predators feeding on Mercenaria spent less time foraging than those feeding on Mya. Mya may retain a low-density refuge from predation even with the loss of structurally complex habitats, though a loss of habitat refuge may result in clam densities that are not sustainable. A better understanding of density-dependent predator-prey interactions is necessary to prevent loss of food-web integrity and to conserve marine resources.

BACTERIOLOGICAL STUDIES ON THE SHELF LIFE1 OF SOFT SHELL CLAMS (Mya arenaria)

1965 ◽  
Vol 28 (2) ◽  
pp. 32-35 ◽  
Author(s):  
J. R. Cox
Keyword(s):  
Chesapeake Bay ◽  
Seasonal Changes ◽  
Mya Arenaria ◽  
Fecal Coliforms ◽  
E Coli ◽  
Soft Shell ◽  
Standard Plate ◽  
Plate Counts ◽  
Early Fall ◽  
Shelf Life Studies

Summary Bacteriological shelf life studies on fresh packed soft shell clams harvested from Chesapeake Bay were conducted at three month intervals to determine the effect of seasonal changes on standard plate counts, 25 C plate counts, coliform most probable numbers, and other microflora in relation to spoilage and discoloration. The data obtained in these studies indicate the following: (a) no correlation between either standard or 25 C plate counts and the degree of spoilage was noted; (b) coliforms multiply in shucked soft shell clams caught in cold waters and stored at 33–35 F, but may decrease during storage when harvested from warmer waters; (c) there may be a slight increase followed by a decrease in E. C.+ and E. coli (fecal coliforms) most probable numbers after 5–7 days storage, but when E.C.+ MPN's have been very low or 0 no increase has been found; (d) no correlation between pink yeast counts and pink discoloration of soft shell clams, or between any chromogenic bacteria or other discolorations was noted; and (e) the bacteriological standards for fresh shucked oysters which are based on E.C.+ MPN's (fecal coliforms) and standard plate counts were met although some counts were in the “Acceptable on Condition” classification when sampling was made during summer and early fall.

scholarly journals Impacts of predators, habitat, recruitment, and disease on soft-shell clamsMya arenariaand stout razor clamsTagelus plebeiusin Chesapeake Bay

2017 ◽  
Author(s):  
Cassandra N. Glaspie ◽  
Rochelle D. Seitz ◽  
Matthew B. Ogburn ◽  
Christopher F. Dungan ◽  
Anson H. Hines
Keyword(s):  
Chesapeake Bay ◽  
Habitat Loss ◽  
Temporal Dynamics ◽  
Influential Factors ◽  
Mya Arenaria ◽  
Environmental Preferences ◽  
Environment Temperature ◽  
Soft Shell ◽  
Parasitic Protist ◽  
Major Factors

ABSTRACTSoft-shell clams,Mya arenaria, and razor clams,Tagelus plebeius, in Chesapeake Bay have declined since the 1970s, with severe declines since the 1990s. These declines are likely caused by multiple factors including warming, predation, habitat loss, recruitment limitation, disease, and harvesting. A bivalve survey in Chesapeake Bay examined influential factors on bivalve populations, focusing on predation (crabs, fish, and cownose rays), habitat (mud, sand, gravel, shell, or seagrass), environment (temperature, salinity, and dissolved oxygen), recruitment, and disease.M. arenariaandT. plebeiuswere found more often in habitats with complex physical structures (seagrass, shell) than any other habitat. Pulses in bivalve density associated with recruitment were attenuated through the summer and fall when predators are most active, indicating that predators likely influence temporal dynamics in these species. Presence ofMya arenaria,which is near the southern extent of its range in Chesapeake Bay, was negatively correlated with water temperature. Recruitment ofM. arenariain Rhode River, MD, declined between 1980 and 2016. Infection by the parasitic protistPerkinsussp. was associated with stressful environmental conditions, bivalve size, and environmental preferences ofPerkinsussp, but was not associated with bivalve densities. It is likely that habitat loss, low recruitment, and predators are major factors keepingT. plebeiusandM. arenariaat low densities in Chesapeake Bay. Persistence at low densities may be facilitated by habitat complexity (presence of physical structures), whereas further reductions in habitats such as seagrass and shell hash could result in local extinction of these important bivalve species.

scholarly journals Two epizootic diseases in Chesapeake Bay commercial clams, Mya arenaria and Tagelus plebeius

2002 ◽  
Vol 50 ◽  
pp. 67-78 ◽  
Author(s):  
CF Dungan ◽  
RM Hamilton ◽  
KL Hudson ◽  
CB McCollough ◽  
KS Reece
Keyword(s):  
Chesapeake Bay ◽  
Mya Arenaria ◽  
Epizootic Diseases

Between ‘Savage Man’ and ‘Most Faithful Englishman’ Manteo and the Early Anglo-Indian Exchange, 1584–1590

Itinerario ◽  
2000 ◽  
Vol 24 (2) ◽  
pp. 146-169 ◽  
Author(s):  
Michael Leroy Oberg
Keyword(s):  
North Carolina ◽  
Chesapeake Bay ◽  
One Year ◽  
Anglo Indian

In August of 1587 Manteo, an Indian from Croatoan Island, joined a group of English settlers in an attack on the native village of Dasemunkepeuc, located on the coast of present-day North Carolina. These colonists, amongst whom Manteo lived, had landed on Roanoke Island less than a month before, dumped there by a pilot more interested in hunting Spanish prize ships than in carrying colonists to their intended place of settlement along the Chesapeake Bay. The colonists had hoped to re-establish peaceful relations with area natives, and for that reason they relied upon Manteo to act as an interpreter, broker, and intercultural diplomat. The legacy of Anglo-Indian bitterness remaining from Ralph Lane's military settlement, however, which had hastily abandoned the island one year before, was too great for Manteo to overcome. The settlers found themselves that summer in the midst of hostile Indians.

Electron Microscopic Study of the Epithelium of the Seminal Vesicle of Aging Rats

1974 ◽  
Vol 32 ◽  
pp. 138-139
Author(s):  
V. F. Allison ◽  
G. C. Fink ◽  
G. W. Cearley
Keyword(s):  
Cell Growth ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Seminal Vesicle ◽  
Seminal Vesicles ◽  
Epithelial Layer ◽  
Epithelial Hyperplasia ◽  
Electron Microscopic ◽  
Aging Rats ◽  
Pseudostratified Epithelium

It is well known that epithelial hyperplasia (benign hypertrophy) is common in the aging prostate of dogs and man. In contrast, little evidence is available for abnormal epithelial cell growth in seminal vesicles of aging animals. Recently, enlarged seminal vesicles were reported in senescent mice, however, that enlargement resulted from increased storage of secretion in the lumen and occurred concomitant to epithelial hypoplasia in that species.The present study is concerned with electron microscopic observations of changes occurring in the pseudostratified epithelium of the seminal vescles of aging rats. Special attention is given to certain non-epithelial cells which have entered the epithelial layer.

Intranuclear Crystals in Regenerating Canine Kidneys

1973 ◽  
Vol 31 ◽  
pp. 412-413
Author(s):  
D.G. Osborne ◽  
L.J. McCormack ◽  
M.O. Magnusson ◽  
W.S. Kiser
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Tubular Epithelial Cell ◽  
Tubular Epithelial Cells ◽  
Cell Nuclei ◽  
Crystalline Structures ◽  
Small Crystals ◽  
Membrane Bound

During a project in which regenerative changes were studied in autotransplanted canine kidneys, intranuclear crystals were seen in a small number of tubular epithelial cells. These crystalline structures were seen in the control specimens and also in regenerating specimens; the main differences being in size and number of them. The control specimens showed a few tubular epithelial cell nuclei almost completely occupied by large crystals that were not membrane bound. Subsequent follow-up biopsies of the same kidneys contained similar intranuclear crystals but of a much smaller size. Some of these nuclei contained several small crystals. The small crystals occurred at one week following transplantation and were seen even four weeks following transplantation. As time passed, the small crystals appeared to fuse to form larger crystals.

An Established Epithelial Cell Line (NPC/HK1) from a Nasopharyngeal Carcinoma - II. A Sem Study

1982 ◽  
Vol 40 ◽  
pp. 224-225
Author(s):  
Li C.L. ◽  
Chew E.C. ◽  
Huang D.P. ◽  
Ho H.C. ◽  
Mak L.S. ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Epithelial Cell ◽  
Surface Morphology ◽  
Cell Line ◽  
Epithelial Cell Line ◽  
Present Communication ◽  
Cells In Culture ◽  
Sem Study ◽  
Well Differentiated

An epithelial cell line, NPC/HK1, has recently been successfully established from a nasopharyngeal carcinoma of the moderately to well differentiated squamous type. The present communication reports on the surface morphology of the NPC/HK1 cells in culture.

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