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Franck Berthe - One of the best experts on this subject based on the ideXlab platform.
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assessment of haemic neoplasia in different soft shell Clam mya arenaria populations from eastern canada by flow cytometry
Journal of Invertebrate Pathology, 2008Co-Authors: Maryse Delaporte, Rejean Tremblay, P Mckenna, Stephanie Synard, Julie Pariseau, Jeffery Davidson, Franck BertheAbstract:Diagnosis of haemic neoplasia (HN) in the soft shell Clam, Mya arenaria, is often achieved by hematocytology and histology. Since neoplastic cells display tetraploid DNA contents, haemocyte cell cycle analysis was developed for use as a diagnosis tool. The aim of this study was to assess the application of a flow cytometry procedure of cell cycle analysis established for the common cockle, to Clams and to evaluate different thresholds of value for the percentage of tetraploid cells for establishing HN disease status of individual Clams and Clam populations. HN status of six Clam populations from eastern Canada was determined. Results of the present study demonstrate a flow cytometry procedure to be useful for HN diagnosis in Clams. Individual Clams were considered to be affected by HN when presenting at least 20% of haemocytes in S-4N phase; and negative when presenting less that 5% of haemocytes in S-4N phase. As discussed in this paper, intermediate cases represent uncertain diagnoses including either false-negative or false-positive Clams, which are difficult to discriminate. At a population level, an additional threshold of 15% for the mean intensity of the disease is proposed, which means having in the population several individual Clams presenting more than 20% of their haemocytes in S-4N phase. Based on these thresholds of value, only one population was considered as free of HN disease, and one population was unequivocally affected by HN. For the four other Clam populations, further investigations are needed toward development and use of specific and objective biomarkers of HN.
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Patterns of p53, p73 and mortalin gene expression associated with haemocyte polyploidy in the soft-shell Clam, Mya arenaria.
Journal of invertebrate pathology, 2008Co-Authors: Ahmed Siah, Maryse Delaporte, Julie Pariseau, Patty Mckenna, Franck BertheAbstract:The molecular mechanisms by which haemocytes of Clams are transformed in the course of haemic neoplasia remain by far unknown. The aim of this study was to quantify the expression of p53/p73 and mortalin genes, in relation with the ploidy status of Clam haemocytes and to correlate the p53 expression with mortalin expression. For this purpose, soft-shell Clams, Mya arenaria, were collected from an endemic zone for neoplasia. The ploidy of haemocytes was assessed for each individual Clam by flow cytometry using a propidium iodide protocol, while p53/p73 and mortalin gene expressions were quantified by real-time RT-PCR. Results show that haemocytes of some Clams with a moderate percentage (15–50%) of tetraploid cells have a significantly high level of p53 and p73 in comparison with Clams belonging to categories with low ( 50%) of tetraploid cells, where low levels of expression of these genes were observed. Furthermore, mortalin gene expression is strongly correlated (r2 = 0.68, p < 0.01) with p53 gene expression level. This reinforces the hypothesis of a cytoplasmic p53 sequestration mechanism in Clam haemic neoplasia. Further studies are needed to confirm these preliminary results and further unravel the molecular pathways involved in this process. Our results are believed to provide phenotypic foundation for such studies to be undertaken.
Julie Pariseau - One of the best experts on this subject based on the ideXlab platform.
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assessment of haemic neoplasia in different soft shell Clam mya arenaria populations from eastern canada by flow cytometry
Journal of Invertebrate Pathology, 2008Co-Authors: Maryse Delaporte, Rejean Tremblay, P Mckenna, Stephanie Synard, Julie Pariseau, Jeffery Davidson, Franck BertheAbstract:Diagnosis of haemic neoplasia (HN) in the soft shell Clam, Mya arenaria, is often achieved by hematocytology and histology. Since neoplastic cells display tetraploid DNA contents, haemocyte cell cycle analysis was developed for use as a diagnosis tool. The aim of this study was to assess the application of a flow cytometry procedure of cell cycle analysis established for the common cockle, to Clams and to evaluate different thresholds of value for the percentage of tetraploid cells for establishing HN disease status of individual Clams and Clam populations. HN status of six Clam populations from eastern Canada was determined. Results of the present study demonstrate a flow cytometry procedure to be useful for HN diagnosis in Clams. Individual Clams were considered to be affected by HN when presenting at least 20% of haemocytes in S-4N phase; and negative when presenting less that 5% of haemocytes in S-4N phase. As discussed in this paper, intermediate cases represent uncertain diagnoses including either false-negative or false-positive Clams, which are difficult to discriminate. At a population level, an additional threshold of 15% for the mean intensity of the disease is proposed, which means having in the population several individual Clams presenting more than 20% of their haemocytes in S-4N phase. Based on these thresholds of value, only one population was considered as free of HN disease, and one population was unequivocally affected by HN. For the four other Clam populations, further investigations are needed toward development and use of specific and objective biomarkers of HN.
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Patterns of p53, p73 and mortalin gene expression associated with haemocyte polyploidy in the soft-shell Clam, Mya arenaria.
Journal of invertebrate pathology, 2008Co-Authors: Ahmed Siah, Maryse Delaporte, Julie Pariseau, Patty Mckenna, Franck BertheAbstract:The molecular mechanisms by which haemocytes of Clams are transformed in the course of haemic neoplasia remain by far unknown. The aim of this study was to quantify the expression of p53/p73 and mortalin genes, in relation with the ploidy status of Clam haemocytes and to correlate the p53 expression with mortalin expression. For this purpose, soft-shell Clams, Mya arenaria, were collected from an endemic zone for neoplasia. The ploidy of haemocytes was assessed for each individual Clam by flow cytometry using a propidium iodide protocol, while p53/p73 and mortalin gene expressions were quantified by real-time RT-PCR. Results show that haemocytes of some Clams with a moderate percentage (15–50%) of tetraploid cells have a significantly high level of p53 and p73 in comparison with Clams belonging to categories with low ( 50%) of tetraploid cells, where low levels of expression of these genes were observed. Furthermore, mortalin gene expression is strongly correlated (r2 = 0.68, p < 0.01) with p53 gene expression level. This reinforces the hypothesis of a cytoplasmic p53 sequestration mechanism in Clam haemic neoplasia. Further studies are needed to confirm these preliminary results and further unravel the molecular pathways involved in this process. Our results are believed to provide phenotypic foundation for such studies to be undertaken.
Maryse Delaporte - One of the best experts on this subject based on the ideXlab platform.
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assessment of haemic neoplasia in different soft shell Clam mya arenaria populations from eastern canada by flow cytometry
Journal of Invertebrate Pathology, 2008Co-Authors: Maryse Delaporte, Rejean Tremblay, P Mckenna, Stephanie Synard, Julie Pariseau, Jeffery Davidson, Franck BertheAbstract:Diagnosis of haemic neoplasia (HN) in the soft shell Clam, Mya arenaria, is often achieved by hematocytology and histology. Since neoplastic cells display tetraploid DNA contents, haemocyte cell cycle analysis was developed for use as a diagnosis tool. The aim of this study was to assess the application of a flow cytometry procedure of cell cycle analysis established for the common cockle, to Clams and to evaluate different thresholds of value for the percentage of tetraploid cells for establishing HN disease status of individual Clams and Clam populations. HN status of six Clam populations from eastern Canada was determined. Results of the present study demonstrate a flow cytometry procedure to be useful for HN diagnosis in Clams. Individual Clams were considered to be affected by HN when presenting at least 20% of haemocytes in S-4N phase; and negative when presenting less that 5% of haemocytes in S-4N phase. As discussed in this paper, intermediate cases represent uncertain diagnoses including either false-negative or false-positive Clams, which are difficult to discriminate. At a population level, an additional threshold of 15% for the mean intensity of the disease is proposed, which means having in the population several individual Clams presenting more than 20% of their haemocytes in S-4N phase. Based on these thresholds of value, only one population was considered as free of HN disease, and one population was unequivocally affected by HN. For the four other Clam populations, further investigations are needed toward development and use of specific and objective biomarkers of HN.
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Patterns of p53, p73 and mortalin gene expression associated with haemocyte polyploidy in the soft-shell Clam, Mya arenaria.
Journal of invertebrate pathology, 2008Co-Authors: Ahmed Siah, Maryse Delaporte, Julie Pariseau, Patty Mckenna, Franck BertheAbstract:The molecular mechanisms by which haemocytes of Clams are transformed in the course of haemic neoplasia remain by far unknown. The aim of this study was to quantify the expression of p53/p73 and mortalin genes, in relation with the ploidy status of Clam haemocytes and to correlate the p53 expression with mortalin expression. For this purpose, soft-shell Clams, Mya arenaria, were collected from an endemic zone for neoplasia. The ploidy of haemocytes was assessed for each individual Clam by flow cytometry using a propidium iodide protocol, while p53/p73 and mortalin gene expressions were quantified by real-time RT-PCR. Results show that haemocytes of some Clams with a moderate percentage (15–50%) of tetraploid cells have a significantly high level of p53 and p73 in comparison with Clams belonging to categories with low ( 50%) of tetraploid cells, where low levels of expression of these genes were observed. Furthermore, mortalin gene expression is strongly correlated (r2 = 0.68, p < 0.01) with p53 gene expression level. This reinforces the hypothesis of a cytoplasmic p53 sequestration mechanism in Clam haemic neoplasia. Further studies are needed to confirm these preliminary results and further unravel the molecular pathways involved in this process. Our results are believed to provide phenotypic foundation for such studies to be undertaken.
Kwangsik Choi - One of the best experts on this subject based on the ideXlab platform.
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Are Juvenile Manila Clam Ruditapes philippinarum Free from Perkinsus olseni Infection in Korean Waters?
Ocean Science Journal, 2020Co-Authors: Hye-mi Lee, Young-ghan Cho, Hee-do Jeung, Min-seok Jang, Jee Youn Hwang, Kwangsik ChoiAbstract:As a suspension feeder, Manila Clam Ruditapes philippinarum (A. Adams and Reeve 1850) plays a crucial role in the coastal soft bottom ecosystem in the temperate region, linking the benthic primary production to the upper trophic level. Manila Clam density on tidal flats on the west coast of Korea has been declining for the past decades, and infection by the protozoan parasite Perkinsus olseni (Lester and Davis 1981) is one of the major causes for the decline. Recent studies carried out in Japan revealed that P. olseni induces mortalities of the juveniles in their natural habitats, which may lead to the recruitment failure and subsequent decline in the Clam population. In this study, we surveyed P. olseni infection in juvenile Manila Clam occurring on two tidal flats on the Taean coast. Ray’s fluid thioglycollate medium assay (RFTM) revealed that P. olseni infection was not limited to the adult Clams, and the juvenile and small-sized Clams are also infected by P. olseni. As young as four-month-old juveniles from Jugyo tidal flat were infected by P. olseni , with the prevalence (i.e., percentage of the infected individuals) of 75.0% and the intensity of 7.77 × 10^5 cells g^−1 wet tissue weight (WT). The adult Manila Clams (SL > 30 mm) from Jugyo tidal flat showed a prevalence of 96.0%, and the intensity as 5.80 × 10 cells g^−1 WT. The observed infection prevalence and intensity of the juvenile are somewhat comparable to those of the adult Clams, suggesting that a high level of P. olseni infection in the juveniles may lead to mortality and a long term decline in the Clam population density.
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isolation and identification of perkinsus olseni from feces and marine sediment using immunological and molecular techniques
Journal of Invertebrate Pathology, 2010Co-Authors: Kyungil Park, Hyunsung Yang, Hyunsil Kang, Moonjae Cho, Kwangjae Park, Kwangsik ChoiAbstract:Molecular and immunological probes were used to identify various life stages of Perkinsus olseni, a protozoan parasite of the Manila Clam Ruditapes philippinarum, from a marine environment and decomposing Clam tissue. Western blotting revealed that the antigenic determinants of the rabbit anti-P. olseni antibody developed in this study were peptides with molecular masses of 55.9, 24.0, and 19.2kDa. Immunofluorescent assay indicated that the rabbit anti-P. olseni IgG was specific to all life stages, including the prezoosporangium, trophozoite, and zoospore. Perkinsus olseni prezoosporangium-like cells were successfully isolated from marine sediment collected from Hwangdo on the west coast of Korea, where P. olseni-associated Clam mortality has recurred for the past decade. Purified cells were positively stained with the rabbit anti-P. olseni antibody in an immunofluorescence assay, confirming for the first time the presence of P. olseni in marine sediment. Actively replicating zoospores inside the prezoosporangia were observed in the decomposing Clam tissue collected from Hwangdo. P. olseni was also isolated from the feces and pseudofeces of infected Clams and confirmed by PCR. The Clams released 1-2 prezoosporangia per day through feces. The data suggested that the fecal discharge and decomposition of the infected Clam tissue could be the two major P. olseni transmission routes.
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density dependent grwoth and mortality of manila Clam ruditapes philippinarum reared in cages in gomso bay korea
The Korean Journal of Malacology, 2010Co-Authors: Kyungll Park, Hyunsung Yang, Dohyung Kang, Kwangsik ChoiAbstract:Density-dependant growth and mortality rate of Manila Clam Ruditapes philippinarum reared in net cages was investigated in Gomso Bay, Korea where unusually high mortality of Clams has been reported. For the experiment, four groups of Clam cages were set up with a density of 2,000 Clams/㎡ (group A), 1,000 Clams/㎡ (group B), 500 Clams/㎡ (group C) and 100 Clams/㎡ (group D). Mortality and growth of Clams in each experimental cage was monitored biweekly from May 2001 to September 2001. Highest mortality in group A was observed in late August, while highest mortality of rest groups was observed in early September. In September, the cumulative mortality in group A was 99%, while it was 93.2% in group B, 91.2% in group C and 88% in group D. Shell growth rate of Clams in thecages was found to be density dependent; monthly shell length increase was 0.67 ㎜ in group A, 1.33 ㎜ in group B, 1.63 ㎜ in group C and 1.71 ㎜ in group D. Our study indicated that Clam growth and mortality in the Bay is density dependent and the growth and survival rate is negatively correlated with the density.
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application of enzyme linked immunosorbent assay elisa for the study of reproduction in the manila Clam ruditapes philippinarum mollusca bivalvia ii impacts of perkinsus olseni on Clam reproduction
Aquaculture, 2006Co-Authors: Kyungil Park, Antonio Figueras, Kwangsik ChoiAbstract:We investigated the effects of infection by the protozoan Perkinsus olseni on the reproduction of female Manila Clams, Ruditapes philippinarum, from a population in Gomso Bay, Korea. The reproductive effort of the Clams was assessed by ELISA using a Clam egg-specific antibody and was expressed as a weight-based gonadosomatic index (GSI). The number of Perkinsus infecting each Clam was estimated from the gills using Ray’s fluid thioglycollate medium (RFTM) along with a NaOH digestion assay. We found that reproductive effort was negatively correlated with the intensity of the Perkinsus infection: more heavily infected Clams produced fewer eggs during the spawning period from May to August. Frequency of spawning was also negatively correlated with the level of Perkinsus infection; heavily infected Clams (HIC) exhibited a single spawning pulse in late July, whereas lightly infected Clams (LIC) showed three spawning peaks in mid-May, late July, and late August. Egg production of HIC was only 30–75% of LIC during spawning. The level of total protein in LIC was also higher year round than in HIC. In conclusion, our investigation demonstrates that a high level of Perkinsus infection affects spawning frequency and reduces egg production, which may have long-term impacts on Clam recruitment and population growth. D 2005 Published by Elsevier B.V.
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application of enzyme linked immunosorbent assay for studying of reproduction in the manila Clam ruditapes philippinarum mollusca bivalvia i quantifying eggs
Aquaculture, 2004Co-Authors: Kyungil Park, Kwangsik ChoiAbstract:A polyclonal antibody specific to Ruditapes philippinarum egg protein (ME-ab) was developed to quantify Clam eggs using an enzyme-linked immunosorbent assay (ELISA). Western blots revealed that ME-ab reacted with egg proteins of molecular masses 475, 84, and 40 kDa under nonreducing conditions and 330, 96, 64, 50, and 31 kDa under reducing conditions. With ELISA, ME-ab detected between 0.23 and 15 A gm l 1 of Clam egg protein; the number of eggs per Clam was quantified by dividing the weight of the total egg protein by the average weight per egg. Reproductive output, expressed as the gonadosomatic index (GSI), was calculated as the ratio of the egg weight to the total tissue weight. Seasonal changes in reproductive output were measured in Clams collected on a monthly basis from Gomso Bay, Korea. Clam egg protein was detected during all months except January. The monthly mean GSI varied from 0 (January) to 0.25 (August), and the highest GSI (0.389) was recorded from a Clam collected in late July. ELISA indicated that Clams in Gomso Bay spawned when the gonad accounted for 20% of the total tissue weight. The fecundity estimated from individual Clams before spawning ranged from 0.94 to 11.79 million eggs, with a mean of 4.15 million. In conclusion, the ELISA used in this study was a sensitive and rapid method
Xavier De Montaudouin - One of the best experts on this subject based on the ideXlab platform.
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Brown muscle disease: impact on Manila Clam Venerupis (=Ruditapes) philippinarum biology.
Fish and Shellfish Immunology, 2014Co-Authors: Cindy Binias, Patrice Gonzalez, Margot Provost, Christophe Lambert, Xavier De MontaudouinAbstract:This study assessed the effect of Brown Muscle Disease (BMD) on Manila Clam Venerupis philippinarum fitness. BMD was discovered in 2005. It affects the posterior adductor muscle and leads to Clam gaping and eventually death. Three statuses of Clams were compared: buried individuals with no signs of BMD (BUR); Clams at the surface of the sediment with no signs of BMD (SURF) and Clams at the surface of the sediment exhibiting signs of brown muscle disease (BMD). Physiological (condition index), immune (hemocyte parameters) and molecular (gene expressions) parameters collected seasonally were analyzed and compared. Results demonstrated a seasonal pattern in condition index (CI) with peaks in spring/summer and decreases in autumn/winter. At each season, the highest CI was observed in BUR and the lowest CI was observed in BMD. In terms of immune response, phagocytosis rate and capacity were higher in Clams with BMD whereas the health status of the Clams did not influence the total hemocyte count. Genes involved in the immune system (comp, tnf, inter) were upregulated in Clams with BMD. The molecular analysis of gill and posterior muscle showed higher mitochondrial metabolism (cox-1, 16S) in cells of infected Clams, suggesting a stronger energetic demand by these cells. Finally, genes involved in oxidative stress response (cat, sod), detoxification (mt) and DNA repair (gadd45) were also overexpressed due to reactive oxygen species production. Most of the studied parameters underlined a cause-effect correlation between Manila Clam health status (BUR, SUR, BMD) and physiological parameters. An important stress response was observed in BMD-infected Clams at different scales, i.e. condition index, immune parameters and stress-related gene expression.
