Defense Responses of Hemocytes Withdrawn from Crassostrea virginica Infected with Perkinsus marinus

Anderson, Robert S.; Burreson, Eugene M.; Paynter, Kennedy T.

doi:10.1006/jipa.1995.1065

Cited by 72 publications

(44 citation statements)

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“…It is difficult, therefore, to assess the effect of Perkinsus infection on the bivalve haemocyte concentration. Oysters infected with P. marinus tend to show an increase in haemocyte concentration in the haemolymph (Anderson et al 1992(Anderson et al , 1995Chu and La Peyre 1993b;La Peyre et al 1995a,b), while a decreasing trend in haemocyte number has been reported in clams heavily infected with Perkinsus sp. (Ordás et al 2000;Casas 2002).…”

Section: Host-parasite Interactions: Progression Of Infection and Immmentioning

confidence: 99%

Perkinsosis in molluscs: A review

Villalba

Reece

Ordás

et al. 2004

Aquat. Living Resour.

299

243

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-The genus Perkinsus includes protistan parasites infecting marine molluscs throughout the world, some of which are associated with mass mortalities. Life cycle involves vegetative proliferation within the host, by which a cell named trophozoite undergoes successive bipartitioning. Other stages have been observed in vitro or in vivo, depending on the species: hypnospore, zoosporangium and zoospore. Molecular taxonomy supports a close affinity between dinoflagellates and Perkinsus spp. Six species of Perkinsus are currently considered valid: P. marinus, P. olseni, P. qugwadi, P. chesapeaki, P. andrewsi and P. mediterraneus. Histology and, above all, incubation of host tissues in Ray's fluid thioglycollate medium (RFTM) are classic diagnostic methods. In addition, more sensitive and quicker molecular diagnostic techniques based on either immunoassays or PCR have been developed for Perkinsus spp. Epizootiological studies have shown a marked influence of water temperature and salinity on P. marinus infection in oysters Crassostrea virginica, thus determining parasite geographical range and temporal disease dynamics (seasonality). In vitro cultures have been established for four Perkinsus spp. Immune response to infection varies depending on host and involves phagocytosis or encapsulation of the parasite cells by host haemocytes. A polypeptide is secreted by clamTapes philippinarum haemocytes that could kill the parasite. In vitro cultured P. marinus cells secrete proteases that are likely involved in degradation of host tissues. P. marinus can suppress the toxic oxygen radicals produced by host haemocytes. In addition to host death, sublethal effects caused by Perkinsus spp. (reduction of fecundity, growth, and condition) may have significant ecological and economic implications. Various strategies have been assayed to mitigate the consequences of P. marinus epizootics on the oyster industry: modifications of management/culture procedures, selective breeding to obtain resistant oyster strains, and the use of triploid oysters and allochthonous oyster species. Some chemotherapeutants have been proved to inhibit or kill parasite cells in vitro.

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Section: Host-parasite Interactions: Progression Of Infection and Immmentioning

confidence: 99%

Perkinsosis in molluscs: A review

Villalba

Reece

Ordás

et al. 2004

Aquat. Living Resour.

299

243

View full text Add to dashboard Cite

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“…Nevertheless, augmentation of circulating hemocytes have been widely documented in C. virginica heavily infected by P. marinus (see e.g. Anderson et al, 1992;Chu and La Peyre, 1993;Anderson et al, 1995;La Peyre et al, 1995;Anderson et al, 1996). These authors suggest that this increase reflects a mobilisation/production of hemocytes to counteract Perkinsus sp.…”

Section: Diseasesmentioning

confidence: 99%

Variability of the hemocyte parameters of Ruditapes philippinarum in the field during an annual cycle

Flye-Sainte-Marie

Soudant

Lambert

et al. 2009

Journal of Experimental Marine Biology and Ecology

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A field monitoring of hemocyte parameters of the Manila clam Ruditapes philippinarum was conducted from July 2004 to September 2005 in Gulf of Morbihan (France), in order to assess (1) the factors controlling the hemocyte parameters of the Manila clam and (2) their relative contribution to the overall variability of these parameters. Monthly, sixty clams were sampled and Total Hemocyte Count (THC), granulocyte and hyalinocyte counts, phagocytosis, phenoloxidase specific activity, length, flesh dry weight, and condition index were measured individually. Perkinsus sp. infection and Brown Ring Disease symptoms were also monitored.Temperature and trophic resource were also monitored.Results indicate that temperature controls granulocyte counts and subsequently THC. Other environmental factors had no direct influence on the measured hemocyte parameters. Almost all measured parameters were significantly affected by size/age and condition index. There were poor relationships between both pathologies and hemocyte parameters presumably because of low infection intensities. Nevertheless, high Perkinsus sp. infection intensity significantly increased total and granulocyte counts and decreased phagocytosis.An interesting result of this study is that the measured biotic and abiotic factors poorly contribute to the explanation of the total variability of hemocyte parameters. Granulocyte concentration was the best explained parameter. However, only 16.4% of its variance was explained by cumulating temperature, length, condition index and Perkinsus sp. infection effects. This study emphasizes the need for a better understanding of hemocyte functions and the factors modulating these functions.

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“…This selective response suggests that hemocytes were able to kill the parasite, but without involving oxygen-dependant mechanisms (Anderson et al, 2003a). Other parasites also have demonstrated effects on bivalve hemocytes (Anderson et al, 1995;Allam et al, 2001;Cochennec-Laureau et al, 2003;Goedken et al, 2005a, b). Thus, the presence of a parasite can be expected to affect the immune status of a bivalve, modifying responses to other environmental changes such as harmful-algal blooms (HABs) (Hégaret et al, 2007a;da Silva et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Combined effects of a parasite, QPX, and the harmful-alga, Prorocentrum minimum on northern quahogs, Mercenaria mercenaria

Hégaret

Smolowitz

Sunila

et al. 2010

Marine Environmental Research

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a b s t r a c tNorthern quahogs, Mercenaria mercenaria (L.), frequently are infected with the parasite Quahog Parasite Unknown (QPX, Labyrintohomorpha, Thraustochytriales), which can cause morbidity and mortality of the quahogs. Possible interactions between this parasitic disease and exposure to the harmful dinoflagellate Prorocentrum minimum in M. mercenaria were studied experimentally. Quahogs from Massachusetts with variable intensity of QPX infection were exposed, under controlled laboratory conditions, to cultured P. minimum added to the natural plankton at a cell density equivalent to a natural bloom. After 5 days of exposure, individual clams were diagnosed histologically to assess prevalence and intensity of parasitic infection, as well as other pathological conditions. Further, cellular defense status of clams was evaluated by analyzing hemocyte parameters (morphological and functional) using flow-cytometry. Exposure of quahogs to P. minimum resulted in: a lower percentage of phagocytic hemocytes, higher production of reactive oxygen species (ROS), larger hemocyte size, more-numerous hemocytic aggregates, and increased numbers of hemocytes in gills accompanied by vacuolation and hyperplasia of the water-tubular epithelial cells of the gills. Quahogs had a low prevalence of QPX; by chance, the parasite was present only in quahogs exposed to P. minimum. Thus, the effect of QPX alone on the hemocyte parameters of quahogs could not be assessed in this experiment, but it was possible to assess different responses of infected versus non-infected quahogs to P. minimum. QPX-infected quahogs exposed to P. minimum had repressed percentage of phagocytic hemocytes, consistent with immuno-modulating effect of P. minimum upon several molluscan species, as well as smaller hemocytes and increased hemocyte infiltration throughout the soft tissues. This experiment demonstrates the importance of considering interactive effects of different factors on the immunology and histopathology of bivalve shellfish, and highlights the importance of considering the presence of parasites when bivalves are subjected to harmful-algal blooms.

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Defense Responses of Hemocytes Withdrawn from Crassostrea virginica Infected with Perkinsus marinus

Cited by 72 publications

References 0 publications

Perkinsosis in molluscs: A review

Perkinsosis in molluscs: A review

Variability of the hemocyte parameters of Ruditapes philippinarum in the field during an annual cycle

Combined effects of a parasite, QPX, and the harmful-alga, Prorocentrum minimum on northern quahogs, Mercenaria mercenaria

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