Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Animal Sciences (166)
- Aquaculture and Fisheries (164)
- Marine Biology (109)
- Immunology and Infectious Disease (22)
- Microbiology (12)
-
- Parasitology (11)
- Physical Sciences and Mathematics (9)
- Environmental Microbiology and Microbial Ecology (8)
- Environmental Sciences (8)
- Pharmacology, Toxicology and Environmental Health (7)
- Toxicology (7)
- Environmental Health (4)
- Immunology of Infectious Disease (4)
- Genetics (3)
- Genetics and Genomics (3)
- Virology (3)
- Ecology and Evolutionary Biology (2)
- Environmental Indicators and Impact Assessment (2)
- Agricultural and Resource Economics (1)
- Environmental Health and Protection (1)
- Environmental Monitoring (1)
- Immunity (1)
- Oceanography (1)
- Oceanography and Atmospheric Sciences and Meteorology (1)
- Ornithology (1)
- Other Ecology and Evolutionary Biology (1)
- Pathogenic Microbiology (1)
- Social and Behavioral Sciences (1)
- Zoology (1)
Articles 241 - 270 of 281
Full-Text Articles in Life Sciences
Disease Processes Of The Parasite Perkinsus Marinus In Eastern Oyster Crassostrea Virginica: Minimum Dose For Infection Initiation, And Interaction Of Temperature, Salinity And Infective Cell Dose, Fle Chu, Ak Volety
VIMS Articles
Experiments were conducted to: (1) test the response of oysters to different doses of the oyster parasite Perkinsus marinus and to 2 stages, meronts or prezoosporangia; and (2) investigate the synergistic effects of temperature, salinity and infective cell concentration on P. marinus infection in oysters. A dose-dependent response of P. marinus infection was found in oysters inoculated with 0, 10, 10(2), 10(4), and 10(5) meronts or prezoosporangia per oyster and maintained at 22 to 25 degrees C and 14 to 21 ppt for 8 to 12 wk. The minimum dose required to infect oysters was 10(2) meronts or prezoosporangia per …
Development Of A Protein-Free Chemically Defined Culture Medium For The Propagation Of The Oyster Pathogen Perkinsus Marinus, Jf Lapeyre, M Faisal
Development Of A Protein-Free Chemically Defined Culture Medium For The Propagation Of The Oyster Pathogen Perkinsus Marinus, Jf Lapeyre, M Faisal
VIMS Articles
In the present study we describe a protein-free, chemically defined culture medium, designated JL-ODRP-3, which supports the propagation of Perkinsus marinus, a parasite of the eastern oyster, Crassotrea virginica. P. marinus adapted rapidly to the defined medium and the growth rate of the protozoan increased significantly following a few subcultures. Two isolates of P. marinus, one from the Chesapeake Bay (Virginia) and the other from the Gulf of Mexico (Texas) were cultured for at least ten passes. The doubling times far the isolates from Virginia and Texas, in Jog phase, were 18 +/- 1.2 and 28.6 +/- 3.2 hours respectively, …
Enumeration Of Enterococcus Sp. Using A Modified Me Method, Mw Rhodes, H Kator
Enumeration Of Enterococcus Sp. Using A Modified Me Method, Mw Rhodes, H Kator
VIMS Articles
A modified mE medium (mEI) containing the chromogenic substrate indoxyl-beta-D-glucoside to detect beta-D-glucosidase activity was evaluated with respect to specificity and recovery of enterococci from environmental eaters. Extending incubation from 24 to 48 h improved enterococci recovery but 77% of the colonies classified as non-target were confirmed as enterococci. Randomly chosen enterococcal isolates from sewage, exposed in microcosms containing 0.22 mu m membrane filtered fresh or estuarine water, exhibited differences in persistence as a function of exposure treatment. Decreasing the concentration of or eliminating indoxyl-beta-D-glucoside from mE did not significantly affect recovery of purified isolates.
Trends In Research On Crassostrea Virginica And Its Two Protozoan Parasites Perkinsus Marinus And Haplosporidium Nelsoni, Fu-Lin Chu
VIMS Articles
The protozoan parasites, Perkinsus marinus (Dermo) and Haplosporidium nelsoni (MSX), are two important pathogens which have caused severe mortality in the eastern oyster, Crassostrea virginica, in the United States since 1950. This paper reviews and discusses the recent research on the diseases caused by these two parasites and focuses on: I. the in vivo and in vitro interactions between C. virginica and P. marinus, 2. the physiological and biochemical characterization of the parasite, P. marinus, and 3. the development of DNA probes and polymerase chain reaction (PCR) primers specific for H. nelsoni or P. marinus.
Research Needs For The Risk Assessment Of Health And Environmental Effects Of Endocrine Disruptors: A Report Of The Us Epa-Sponsored Workshop, Rj Kavlock, Gp Daston, C Derosa, P Fennercrisp, Le Gray, S Kaattari, Et Al
Research Needs For The Risk Assessment Of Health And Environmental Effects Of Endocrine Disruptors: A Report Of The Us Epa-Sponsored Workshop, Rj Kavlock, Gp Daston, C Derosa, P Fennercrisp, Le Gray, S Kaattari, Et Al
VIMS Articles
The hypothesis has been put forward that humans and wildlife species have suffered adverse health effects after exposure to endocrine-disrupting chemicals. Reported adverse effects include declines in populations, increases in cancers, and reduced reproductive function. The U.S. Environmental Protection Agency sponsored a workshop in April 1995 to bring together interested parties in an effort to identify research gaps related to this hypothesis and to establish priorities for future research activities. Approximately 90 invited participants were organized into work groups developed around the principal reported health effects-carcinogenesis, reproductive toxicity, neurotoxicity, and immunotoxicity--as well as along the risk assessment paradigm--hazard identification, dose-response …
An Unidentified Haplosporidian Parasite Of Bay Scallop Argopecten Irradians Cultured In The Shandong And Liaoning Provinces Of China, Fle Chu, Em Burreson, F Zhang, K Chew
An Unidentified Haplosporidian Parasite Of Bay Scallop Argopecten Irradians Cultured In The Shandong And Liaoning Provinces Of China, Fle Chu, Em Burreson, F Zhang, K Chew
VIMS Articles
Since 1988 growers of bay scallop Argopecten irradians in China have been experiencing mortality in their cultured stocks. Although poorly documented, mortality apparently began near Qingdao and has since spread to other areas of Shandong and Liaoning provinces. Samples of cultured scallops were collected from several growing areas in these provinces and analyzed by histological methods for pathogens. An unidentified haplosporidian parasite was observed in a high proportion of scallops from two of the stocks examined. Most infections were of low intensity, but one heavy infection was also observed. Only plasmodia stages were observed; they occurred intercellularly in connective tissues …
Enhanced Immunogenicity Of Renibacterium Salmoninarum In Chinook Salmon After Removal Of The Bacterial Cell Surface-Associated 57 Kda Protein, Pa Wood, Sl Kaattari
Enhanced Immunogenicity Of Renibacterium Salmoninarum In Chinook Salmon After Removal Of The Bacterial Cell Surface-Associated 57 Kda Protein, Pa Wood, Sl Kaattari
VIMS Articles
A study was conducted to determine the effect of endogenous serine protease activity on the immunogenicity of Renibacterium salmoninarum cells in chinook salmon Oncorhynchus tshawytscha. Salmon were immunized with either R. salmoninarum cells possessing p57 (p57(+)) or substantially depleted of p57 (p57(-)). The resultant antisera were examined by whole cell ELISA and immunoblot procedures using p57(+), p57(-), proteinase-K-treated, and periodate-treated whole cells. These analyses revealed that the removal of p57 by the endogenous serine protease significantly enhanced the immunogenicity of the cell, resulting in a 20-fold increase in detectable antibody titers. The bulk of this antibody activity was directed at …
Histopathology Of The Renal And Splenic Haemopoietic Tissues Of Coho Salmon Oncorhynchus Kisutch Experimentally Infected With Renibacterium Salmoninarum, E Flano, P Lopez-Fierro, B Razquin, S Kaattari, A Villena
Histopathology Of The Renal And Splenic Haemopoietic Tissues Of Coho Salmon Oncorhynchus Kisutch Experimentally Infected With Renibacterium Salmoninarum, E Flano, P Lopez-Fierro, B Razquin, S Kaattari, A Villena
VIMS Articles
We report the histopathological changes occurring in the renal and splenic haemopoietic tissues of coho salmon Oncorhynchus kisutch experimentally infected with renibacterium salmoninarum. In both tissues we were able by light microscopy to distinguish 3 different grades in the progression of the infection. The grades of infection were characterized according to the location of the bacteria and the tissue injuries. Ultrastructural observation revealed sinusoidal cells, macrophages, reticular and barrier cells to be infected by the pathogen, and necrosis of the tissue to be general in advanced stages of the infection. Despite destruction of the haemopoietic tissue, plasmacytopoietic foci were frequently …
Epizootiology Of Perkinsus Marinus Disease Of Oysters In Chesapeake Bay, With Emphasis On Data Since 1985, Eugene Burreson, Lisa M. Ragone Calvo
Epizootiology Of Perkinsus Marinus Disease Of Oysters In Chesapeake Bay, With Emphasis On Data Since 1985, Eugene Burreson, Lisa M. Ragone Calvo
VIMS Articles
Since 1987 Perkinsus marinus has been the most important pathogen of the eastern oyster, Crassostrea virginica, in Chesapeake Bay because of its widespread distribution and persistence in low salinity areas. The pathogen became established on all oyster beds in the Chesapeake Bay as a result of natural spread during the consecutive drought years from 1985 to 1988 or by movement of infected oysters during the same period. Elevated salinities resulting from drought conditions and concomitant warm winters allowed P. marinus to proliferate in what were historically low salinity areas. Oyster mortality was high on most beds and landings of market …
Propagation And In Vitro Studies Of Perkinsus Marinus, Jerome F. Lapeyre
Propagation And In Vitro Studies Of Perkinsus Marinus, Jerome F. Lapeyre
VIMS Articles
The development of continuous cultures of Perkinsus marinus (Apicomplexa) is a major breakthrough that will lead to a better understanding of this deadly oyster pathogen. More than 10 P. marinus isolates are currently in continuous cultures. Culture media used to propagate P. marinus range from media designed for the culture of mammalian cells to protein-free chemically defined media. Continuous cultures of P. marinus can be initiated from a variety of infected oyster tissues or from isolated hypnospores (i.e., the enlarged stage of P. marinus from oyster tissue incubated in Ray's fluid thioglycollate medium). P. marinus cells adapt well to culture …
Optimal Culture Conditions For The Propagation Of The Oyster Pathogen Perkinsus Marinus (Apicomplexa) In Protein Deficient Medium, Jf Lapeyre, M Faisal
Optimal Culture Conditions For The Propagation Of The Oyster Pathogen Perkinsus Marinus (Apicomplexa) In Protein Deficient Medium, Jf Lapeyre, M Faisal
VIMS Articles
The protozoan, Perkinsus marinus, acclimated and proliferated in the culture medium JL-ODRP-1 without bovine serum albumin. The principal culture conditions for the optimal propagation of P. marinus in this protein deficient culture medium, were determined. The greatest growth rates of the parasite occurred at 28 degrees C, 661 mOsm/kg and pH 7.5. Decreasing seeding densities from 16 x 10(5) to 1 x 10(5) also increased growth rate. After several passages in the absence of 5% CO2 tension, the growth rate of P. marinus was similar to its original value in the presence of 5% CO2 tension. This protein deficient culture …
Shell Disease In The Gold Lip Pearl Oyster, Pinctada Maxima And The Eastern Oyster, Crassostrea Virginica, Frank O. Perkins
Shell Disease In The Gold Lip Pearl Oyster, Pinctada Maxima And The Eastern Oyster, Crassostrea Virginica, Frank O. Perkins
VIMS Articles
A description is provided of the anomalous conchiolin deposits which are formed by Pinctada maxima and which are associated with unusual morta]jties. Comparisons are made with brown ring disease found in Ruditapes philippinarum and juvenile Crassostrea virg inica. In P. maxima, the deposits are not organized into a ring but rather a.re broad-based and result in retraction of the mantle with the deposits lying outside the edge of the mantle. Vibrio sp. have been implicated in causing the di seases of P. max ima and R. philippinarum whereas the etiological agent of the disease in C. virginica is unknown. It …
A Comparison Of Crassostrea Gigas And Crassostrea Virginica: Effects Of Temperature And Salinity On Susceptibility To The Protozoan Parasite, Perkinsus Marinus, Fu-Lin C. Chu, Aswani Volety, G Constantin
A Comparison Of Crassostrea Gigas And Crassostrea Virginica: Effects Of Temperature And Salinity On Susceptibility To The Protozoan Parasite, Perkinsus Marinus, Fu-Lin C. Chu, Aswani Volety, G Constantin
VIMS Articles
The susceptibility of diploid and triploid (2N and 3N) Crassostrea gigas to Perkinsus marinus was compared, in the laboratory, with that of Crassostrea virginica al three test temperatures (10, 15, and 25 degrees C) at 20-22 ppt and at three test salinities (3, 10, and 20 ppt) at a temperature of 19-22 degrees C. Experimental oysters were challenged twice with freshly isolated P, marinus meronts, after acclimation to test temperatures and salinities. Although infection prevalence and intensity increased with temperature (p = 0.0001) and salinity in P. marinus-challenged oysters of both oyster species: they were highest in C. virginica groups. …
Foreword, Frank O. Perkins
History Of Perkinsus Marinus, A Pathogen Of Oysters In Chesapeake Bay 1950-1984, Jd Andrews
History Of Perkinsus Marinus, A Pathogen Of Oysters In Chesapeake Bay 1950-1984, Jd Andrews
VIMS Articles
The pathogen Perkinsus marinus (Dermo) was discovered in Chesapeake Bay in 1950. It was already widely distributed in the Bay and caused annual mortality below the mouth of the Rappahannock River. Annual mortality in trayed oysters at the Virginia Institute of Marine Science (VIMS) varied annually from 24% to 57% at this most favorable site for the disease. Over 2 million bushels of seed oysters from the James River public beds were transplanted annually to private beds in 4 major growing areas. These were Hampton Roads, lower Bay proper, Mobjack Bay at mouth of York River, and the Rappahannock River. …
Laboratory Investigations Of Susceptibility, Infectivity, And Transmission Of Perkinsus Marinus In Oysters, Fu-Lin C. Chu
Laboratory Investigations Of Susceptibility, Infectivity, And Transmission Of Perkinsus Marinus In Oysters, Fu-Lin C. Chu
VIMS Articles
The protozoan parasite, Perkinsus marinus (Dermo), has caused significant mortality in the eastern oyster, Crassostrea virginica, along the east coast of the United States and the Gulf of Mexico, since the 1950s. Because of its current expanded distribution and increased abundance, P. marinus is now considered more prevalent in the mid-Atlantic waters and the Chesapeake Bay in particular, than another protozoan pathogen, Haplosporidium nelsoni (MSX). The susceptibility, infectivity/pathogenicity, and transmission of P. marinus in eastern oysters were investigated in numerous laboratory studies, The influence of environmental factors such as temperature, salinity, and pollution on the interaction between the host oyster …
The Structure Of Perkinsus Marinus (Mackin, Owen And Collier, 1950) Levine, 1978 With Comments On Taxonomy And Phylogeny Of Perkinsus Spp., Frank O. Perkins
The Structure Of Perkinsus Marinus (Mackin, Owen And Collier, 1950) Levine, 1978 With Comments On Taxonomy And Phylogeny Of Perkinsus Spp., Frank O. Perkins
VIMS Articles
A description of the structure of the Crassostrea virginica pathogen Perkinsus marinus is provided from observations at the light and transmission electron microscope levels of detail and includes cellular multiplication (palintomy) in the host and zoosporulation in estuarine water as well as observations of cells in axenic culture. The description is primarily a review of previously published information; however, new information is provided on development of walled outgrowths from hypnospores derived from fluid thioglycollate medium treatment of infected host tissue. The protoplast within the outgrowths subdivides to yield small unicells which escape into the ambient water, or the protoplast emerges …
Detection Of Haplosporidium-Nelsoni (Haplosporidia, Haplosporidiidae) In Oysters By Pcr Amplification, Na Stokes, Me Siddall, Em Burreson
Detection Of Haplosporidium-Nelsoni (Haplosporidia, Haplosporidiidae) In Oysters By Pcr Amplification, Na Stokes, Me Siddall, Em Burreson
VIMS Articles
Haplosporidium nelsoni is a protistan pathogen of the eastern oyster Crassostrea virginica, and has contributed to the decline of the oyster population in the Chesapeake Bay. From comparison of the sequence data of the 16S-like rDNA of H. nelsoni with those of Minchinia teredinis and other related organisms, 2 oligonucleotides which were specific to H. nelsoni and suitable for use as PCR primers were identified. These primers amplified a 564 base pair fragment of the small subunit (SSU) rRNA gene of H. nelsoni, but did not amplify genomic oyster DNA or the SSU rRNA genes of the haplosporidians Haplosporidium costale, …
Heat-Shock Proteins Of The Oyster Parasite Perkinsus-Marinus, Ct Tirard, Rm Grossfeld, Ak Volety, Fle Chu
Heat-Shock Proteins Of The Oyster Parasite Perkinsus-Marinus, Ct Tirard, Rm Grossfeld, Ak Volety, Fle Chu
VIMS Articles
The susceptibility of the eastern oyster Crassostrea virginica to infection by the protozoan parasite Perkinsus marinus is influenced by temperature. Because of the crucial roles of heat shock proteins in cellular thermal tolerance and in host-parasite adaptations in other species, we compared the in vitro heat shock responses of cultured P. marin us and of oyster hemocytes. The parasite and host heat shock proteins were different in size and in immunochemical specificity. In addition, the thermal threshold for inducing the response was higher for P. marinus acclimated to the same temperature as the oysters. The results suggest that EI marinus …
Perkinsus-Marinus (Apicomplexa) As A Potential Source Of Oyster Crassostrea-Virginica Mortality In Coastal Lagoons Of Tabasco, Mexico, Em Burreson, Rs Alvarez, W Martinez, La Macedo
Perkinsus-Marinus (Apicomplexa) As A Potential Source Of Oyster Crassostrea-Virginica Mortality In Coastal Lagoons Of Tabasco, Mexico, Em Burreson, Rs Alvarez, W Martinez, La Macedo
VIMS Articles
Poorly documented, but apparently sporadic oyster Crassostrea virginica mortality in the coastal lagoons Carmen, Machona and Mecoacan at the southern extreme of the Gulf of Mexico in Tabasco, Mexico, has been attributed by local oystermen to pollution resulting from oil refinery operations. In September 1992 we sampled oysters in these lagoons to investigate the potential for disease-induced mortality from the oyster pathogen Perkinsus marinus. Prevalence of P. marinus was 100% at Lodazal, a high salinity (31 ppt) site in Carmen lagoon and 60% at Rio San Felipe, a low salinity (15 ppt) site. At Los Jimenez, a high salinity (32 …
Hematodinium-Australis N-Sp, A Parasitic Dinoflagellate Of The Sand Crab Portunus-Pelagicus From Moreton Bay, Australia, Da Hudson, Jeffrey D. Shields
Hematodinium-Australis N-Sp, A Parasitic Dinoflagellate Of The Sand Crab Portunus-Pelagicus From Moreton Bay, Australia, Da Hudson, Jeffrey D. Shields
VIMS Articles
A new species of parasitic dinoflagellate is described from the portunid crab Portunus pelagicus. The dinoflagellate is a member of the genus Hematodinium which formerly consisted of a single species, H. perezi. Members of the genus have been reported in crabs and lobsters from Europe and North America, where in some circumstances they cause significant mortalities to host populations. The new species is the first member of the family Syndinidae to be fully described from Australia. The new species differs from other forms of Hematodinium primarily by the size of the trophont (vegetative stage), the ovoid plasmodium, and the small …
Exocrine Pancreatic Neoplasms In The Mummichog (Fundulus Heteroclitus) From A Creosote-Contaminated Site, John W. Fournie, Wolfgang K. Vogelbein
Exocrine Pancreatic Neoplasms In The Mummichog (Fundulus Heteroclitus) From A Creosote-Contaminated Site, John W. Fournie, Wolfgang K. Vogelbein
VIMS Articles
A high prevalence of exocrine pancreatic neoplasms occurred in mummichog, Fundulus heteroclitus, from a creosote-contaminated site in the Elizabeth River, Virginia. A total of 20 neoplasms were found in a group of about 1,300 fish obtained at this site over a 2-yr period. Of 240 fish collected during October 1991, 3.3% had pancreatic neoplasms. Adjusted total lesion prevalence for large adult fish (Size Class III: total length = 75–85 mm; Size Class IV: total length > 85 mm) was 6.7%. Pancreatic neoplasms were not observed in 234 fish collected at this site during May 1991, nor were they found in …
In-Vitro And In-Vivo Effects Of 8 Chemotherapeutants On The Oyster Parasite Perkinsus-Marinus (Mackin, Owen, And Collier), Gustavo W. Calvo, Eugene M. Burreson
In-Vitro And In-Vivo Effects Of 8 Chemotherapeutants On The Oyster Parasite Perkinsus-Marinus (Mackin, Owen, And Collier), Gustavo W. Calvo, Eugene M. Burreson
VIMS Articles
Eight therapeutants were tested for in vitro inhibition of Perkinsus marinus (Mackin, Owen, and Collier) enlargement and in vivo control of established infections. In addition, acute toxicity of six anticoccidials to oysters was determined. For in vitro experiments 0.2 ml aliquots of infected hemolymph were exposed to 5 concentrations (100 mg/l, 10 mg/l, 1 mg/l, 0.1 mg/l and 0.01 mg/1) of amprolium, arprinocid, cycloheximide, lasalocid, malachite green, monensin, sulfadimethoxine, and a potentiated sulfadimethoxine. Exposure lasted 1 day and was followed by incubation in fluid thioglycollate medium. Lasalocid and malachite green were the most effective compounds, showing significant anti-P. marinus activity …
Characterization Of Overwintering Infections Of Perkinsus-Marinus (Apicomplexa) In Chesapeake Bay Oysters, Lisa M. Ragone Calvo, Em Burreson
Characterization Of Overwintering Infections Of Perkinsus-Marinus (Apicomplexa) In Chesapeake Bay Oysters, Lisa M. Ragone Calvo, Em Burreson
VIMS Articles
To determine the nature and abundance of over-wintering P. marinus infections, infected oysters (Crassostrea virginica) collected from the upper James River, VA, were placed in a tray and suspended from a pier in the lower York River, VA in November 1991. Every six weeks through May 1992 oysters (n = 25) were removed from the tray, examined for P. marinus by hemolymph culture in fluid thioglycollate medium (FTM), gradually warmed in individual containers to 25-degrees-C and held for one month. After the incubation period, which permitted the development of very light and/or cryptic parasite stages to detectable levels, the oysters …
Growth And Mortality Of Eastern Oysters, Crassostrea-Virginica (Gmelin, 1791), And Pacific Oysters, Crassostrea-Gigas (Thunberg, 1793) Under Challenge From The Parasite, Perkinsus-Marinus, Bruce J. Barber, Roger L. Mann
Growth And Mortality Of Eastern Oysters, Crassostrea-Virginica (Gmelin, 1791), And Pacific Oysters, Crassostrea-Gigas (Thunberg, 1793) Under Challenge From The Parasite, Perkinsus-Marinus, Bruce J. Barber, Roger L. Mann
VIMS Articles
Stocks of oysters Crassostrea virginica and C. gigas were produced in the Virginia Institute of Marine Science (VIMS) hatchery in April 1991 and grown in two quarantined flumes receiving water from the York River, VA. From July 1991 through November 1992, growth and mortality of both species were compared. Also, beginning in June 1992 one flume (containing one group of each species) was ''dosed'' (oysters infected with P. marinus added) and the other flume remained ''undosed'' (no infected oysters added). Disease prevalence and intensity, mortality, and shell height were compared both within (between undosed and dosed groups) and between species. …
Quantifying Seasonal-Variation In Somatic Tissue - Surfclam Spisula-Solidissima (Dillwyn, 1817) - A Case-Study, Joseph G. Loesch, David A. Evans
Quantifying Seasonal-Variation In Somatic Tissue - Surfclam Spisula-Solidissima (Dillwyn, 1817) - A Case-Study, Joseph G. Loesch, David A. Evans
VIMS Articles
Condition indexes are commonly derived from bivalve species. Usable meat yields (UMY, in l/bu) from 181 daily landings of Atlantic surfclams, Spisula solidissima (Dellwyn, 1817), at a Virginia processing plant in 1974 and 160 landings in 1975 were used as an index in our analysis. The data were fitted to a basic sinusoidal model and a two-compartment sinusoidal model to demonstrate the utility of these models for quantifying cyclic events. The basic model, x = x(0) + A cos2 pi t + B sin2 pi t, is linear in its independent variables and fitted by multiple regression, with x = …
Comparison Of Infectivity And Pathogenicity Of Meront (Trophozoite) And Prezoosporangiae Stages Of The Oyster Pathogen Perkinsus-Marinus In Eastern Oysters, Crassostrea-Virginica (Gmelin, 1791), Aswani Volety, Fu-Lin E. Chu
Comparison Of Infectivity And Pathogenicity Of Meront (Trophozoite) And Prezoosporangiae Stages Of The Oyster Pathogen Perkinsus-Marinus In Eastern Oysters, Crassostrea-Virginica (Gmelin, 1791), Aswani Volety, Fu-Lin E. Chu
VIMS Articles
Two experiments were conducted to compare the infectivity and pathogenicity of two life stages of the parasite Perkinsus marinus, meronts (trophozoites) and prezoosporangia (hypnospores), in eastern oysters, Crassostrea virginica. Oysters were inoculated with 5 X 10(4) meronts or prezoosporangia per oyster by injection into the shell cavity. Prevalence and intensity of P. marinus infections, condition index, serum protein concentrations, and lysozyme activities were measured in oysters after 15, 25, 40, and 65 days in experiment 1 and after 20, 40, 50, 65, and 75 days postchallenge by P. marinus cells in experiment 2. Controls were injected with filtered York River …
Perkinsus Marinus Susceptibility And Defense-Related Activities In Eastern Oysters Crassostrea Virginica: Temperature Effects, Fu-Lin E. Chu, Jerome F. La Peyre
Perkinsus Marinus Susceptibility And Defense-Related Activities In Eastern Oysters Crassostrea Virginica: Temperature Effects, Fu-Lin E. Chu, Jerome F. La Peyre
VIMS Articles
he relationship of potential defense-related cellular and humoral activities and the sus- ceptibility of eastern oysters Crassostrea virginica to the parasite Perkinsus marinus were examined at 10, 15, 20 and 25 "C. Oysters were acclimated at experimental temperatures for 20 d and then chal- lenged with R marinus. Total hemocyte counts (TC) and percentage of granulocytes (PG) 20 d after temperature acclimation were higher in oysters at high than at low acclimation temperature. Higher protein (P) and lysozyme (L) concentrations were found in oysters at 10 and 15 "C. No significant differ- ences in hemagglutination (H) titers due to temperature …
Development Of Disease Caused By The Parasite, Perkinsus-Marinus And Defense-Related Hemolymph Factors In 3 Populations Of Oysters From The Chesapeake Bay, Usa, Fu-Lin C. Chu, J.F. La Peyre
Development Of Disease Caused By The Parasite, Perkinsus-Marinus And Defense-Related Hemolymph Factors In 3 Populations Of Oysters From The Chesapeake Bay, Usa, Fu-Lin C. Chu, J.F. La Peyre
VIMS Articles
The development of infection caused by the protozoan parasite, Perkinsus marinus (Dermo) and some specific potential defense-related cellular and humoral components in oysters collected from three geographic areas, Deepwater Shoal of James River (DW), Wachapreague (WP), and Mobjack Bay (MJ) were examined over time. Oysters were maintained in estuarine water (salinity = 20 ppt) or in water at a salinity similar to the ambient salinity of the collection sites. Oysters were sampled at the initiation of the experiment (day 0), day 35, and day 100 to determine defense-related parameters and disease prevalence and intensity. All populations experienced a significant increase …
Spatial And Temporal Bacterioplankton Dynamics During Destratification Of The James River Estuary, Virginia, Usa, Et Koepfler, Hi Kator, Rl Wetzel, Lw Haas
Spatial And Temporal Bacterioplankton Dynamics During Destratification Of The James River Estuary, Virginia, Usa, Et Koepfler, Hi Kator, Rl Wetzel, Lw Haas
VIMS Articles
Bacterioplankton abundance and production were examined over the course of a destratification event in the lower James River, Virginia, USA, Goals of the study were to determine if destratification would influence temporal patterns of bacterioplankton parameters and relationships between bacterioplankton and other biological and abiological parameters. Mean bacterial abundance grouped over stations did not change over the course of the study, and were characterized by much smaller coefficients of variation than all other planktonic constituents. However, bacterial production measured by H-3-thymidine (H-3-Tdr) incorporation decreased significantly from a stratified (324 mu g Cl-1 d(-1)) to a destratified (187 mu g Cl-1 …