Effects of temperature on hard clam (Mercenaria mercenaria) immunity and QPX (Quahog Parasite Unknown) disease development: II. Defense parameters

Functional and metabolic characterization of hemocytes of the green mussel, Perna viridis: in vitro impacts of temperature

“…Increase of ROS production is thought to be related to increase in respiration at high temperature, as stated above. In contrast, results from our study showed that unstimulated oxidative metabolism was highest at 10 C and decreased at 20 and 30 C. Perrigault et al [70] reported similar observation with hemocytes of Mercenaria mercenaria maintained for 2 and 4 months at 13, 21 and 27 C. In these cases, low temperature exposures might represent stressful conditions for the studied species, while the higher temperatures remained under the stress threshold, as suggested for phagocytic activity. However, due to the current lack of fundamental knowledge about the tight relations between oxidative metabolism, mitochondrial activity and environmental conditions in bivalves, present results do not allow us to definitely conclude this relationship.…”

“…Similarly, Carballal et al [51] found that the percentage of phagocytic hemocytes from M. galloprovincialis was lower at 10 C than at 20 C and 30 C. Contrastingly, Hégaret et al [43], Monari et al [71] and Yu et al [72] reported a decrease in phagocytosis activity with an increase of temperature, respectively in the eastern oyster C. virginica, the clam Chamelea gallina and the Surf clam Mactra veneformis. At last, while no difference between phagocytosis at 15 and 21 C could be observed in both the clam Ruditapes decussatus and the mussel M. galloprovincialis [73], Perrigault et al [70] reported a higher phagocytic activity at 21 C than at 13 and 27 C in the hard clam Mercenaria mercenaria. Then, as suggested by Monari et al [71], temperatures above or below a certain threshold may result in stressful conditions for hemocytes, so that they are less responsive.…”

“…Temperature is among the most important environmental factors affecting the biology of hemocytes in bivalves [29,61,70]. In the present work, we submitted hemocytes to acute in vitro temperature variations.…”

Differential immune response in the hard clam (mercenaria mercenaria) against bacteria and the protistan pathogen QPX (quahog parasite unknown)

“…Hemolymph samples (generally 1.2e1.8 ml) were withdrawn from the adductor muscle with a 1 ml-syringe and held on ice. A volume of 650 ml hemolymph was diluted (vol:vol) in ice-cold FASW and used for the assessment of clam immune parameters following the procedures described in Perrigault et al [34]. Total (THC) and differential (% of granulocytes) hemocyte counts as well as percentage of dead cells were assessed on a FACSCalibur flow cytometer (Becton Dickinson Biosciences) equipped with a 488 nm laser by counting 10,000 events [34].…”

“…A volume of 650 ml hemolymph was diluted (vol:vol) in ice-cold FASW and used for the assessment of clam immune parameters following the procedures described in Perrigault et al [34]. Total (THC) and differential (% of granulocytes) hemocyte counts as well as percentage of dead cells were assessed on a FACSCalibur flow cytometer (Becton Dickinson Biosciences) equipped with a 488 nm laser by counting 10,000 events [34]. Reactive oxygen species (ROS) production was measured before (unstimulated or native) and after stimulation (5 min poststimulation) of hemocytes with zymosan A using 2 0 ,7 0 -dichlorofluorescein-di-acetate (DCFH-DA, Calbiochem) and procedures according to Perrigault et al [34].…”