Development and applications of Ray’s fluid thioglycollate media for detection and manipulation of Perkinsus spp. pathogens of marine molluscs

Dungan, Christopher F.; Bushek, David

doi:10.1016/j.jip.2015.05.004

Cited by 27 publications

(13 citation statements)

References 71 publications

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“…A subset of oysters (n = 16) from holding tanks and one oyster from each tank at the end of Experiment 2 (n = 16) were analyzed for prevalence of P. marinus cells, which cause Dermo disease, following the standard Ray's Fluid Thioglycollate Medium (RFTM) protocol 35,36 .…”

Section: Prevalence Of P Marinus Cellsmentioning

confidence: 99%

Combined and independent effects of hypoxia and tributyltin on mRNA expression and physiology of the Eastern oyster (Crassostrea virginica)

Barnett

Gledhill

Griffitt

et al. 2020

Sci Rep

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Oyster reefs are vital to estuarine health, but they experience multiple stressors and globally declining populations. This study examined effects of hypoxia and tributyltin (TBT) on adult Eastern oysters (Crassostrea virginica) exposed either in the laboratory or the field following a natural hypoxic event. In the laboratory, oysters were exposed to either hypoxia followed by a recovery period, or to hypoxia combined with TBT. mRNA expression of HIF1-α and Tβ-4 along with hemocyte counts, biomarkers of hypoxic stress and immune health, respectively, were measured. In field-deployed oysters, HIF1-α and Tβ-4 expression increased, while no effect on hemocytes was observed. In contrast, after 6 and 8 days of laboratory-based hypoxia exposure, both Tβ-4 expression and hemocyte counts declined. After 8 days of exposure to hypoxia + TBT, oysters substantially up-regulated HIF1-α and down-regulated Tβ-4, although hemocyte counts were unaffected. Results suggest that hypoxic exposure induces immunosuppression which could increase vulnerability to pathogens. Oysters are important ecosystem engineers, providing essential fish habitats that are vital to the health of many estuarine ecosystems worldwide 1, 2. Oyster reefs provide numerous critical ecosystem services, including enhancing biodiversity, improving water quality, serving as nursery habitat for commercially important fisheries, stabilizing shorelines, and providing a significant economic resource for coastal communities 2-6. Despite their ecological and economic importance, it is estimated that oyster populations have suffered losses of approximately 85% worldwide in recent years, classifying oyster reefs as one of the most heavily impacted ecosystems in the world 3. Extensive restoration efforts are currently underway to restore oyster reefs in the Gulf of Mexico and other areas of the United States, where these ecosystems once flourished. However, the success of these restoration efforts has lagged far behind that of other estuarine ecosystems 7. Historically, overharvesting played a significant role in the decline of oyster populations 8 , but oyster reef recovery and resilience are also limited by poor water quality, disease, and predation 9,10. In addition, environmental contaminants (e.g., metals, pharmaceuticals, agricultural runoff) have the potential to bioaccumulate in these filter-feeding organisms 11,12. Due to their proximity to land and sources of freshwater, estuaries often experience large fluctuations in environmental conditions, such as temperature, salinity, and dissolved oxygen (DO), that can have negative short-term impacts on oyster reefs 13. The complexity of estuarine systems may result in oysters often facing combinations of stressors simultaneously, and these can have greater detrimental effects than each stressor independently 13,14. Therefore, understanding the impacts of multiple stressors, both alone and in combination, is essential to determine their impacts on aquatic organisms.

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Section: Prevalence Of P Marinus Cellsmentioning

confidence: 99%

Combined and independent effects of hypoxia and tributyltin on mRNA expression and physiology of the Eastern oyster (Crassostrea virginica)

Barnett

Gledhill

Griffitt

et al. 2020

Sci Rep

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“…When a parasite is described for the first time in a new host, it is important to use, when possible, multiple techniques to define the nature of the interaction (e.g., in [41]). Equally important for the choice of the diagnostic technique is to know the limits of the technique and the objective of the study; e.g., Ray's fluid thioglycollate medium technique (RFTM) provides a robust way to quantify parasite cells in the bivalve soft-tissues (reviewed in [42]). Our study was intended to establish a base-line for the presence of the studied protozoans using DNA-based assays.…”

Section: Discussionmentioning

confidence: 99%

A qPCR-Based Survey of Haplosporidium nelsoni and Perkinsus spp. in the Eastern Oyster, Crassostrea virginica in Maine, USA

et al. 2020

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Eastern oyster (Crassostrea virginica) aquaculture is increasingly playing a significant role in the state of Maine’s (USA) coastal economy. Here, we conducted a qPCR-based survey for Haplosporidium nelsoni, Perkinsus marinus, and Perkinsus chesapeaki in C. virginica (n = 1440) from six Maine sites during the summer–fall of 2016 and 2017. In the absence of reported die-offs, our results indicated the continued presence of the three protozoan parasites in the six sites. The highest H. nelsoni qPCR-prevalence corresponded to Jack’s Point and Prentiss Island ( x ¯ = 40 and 48% respectively), both located in the Damariscotta River Estuary. Jack’s Point, Prentiss Island, New Meadows River, and Weskeag River recorded the highest qPCR-prevalence for P. marinus (32–39%). While the P. marinus qPCR-prevalence differed slightly for the years 2016 and 2017, P. chesapeaki qPCR-prevalence in 2016 was markedly lower than 2017 (<20% at all sites versus >60% at all sites for each of the years, respectively). Mean qPCR-prevalence values for P. chesapeaki over the two-year study were ≥40% for samples from Jack’s Point (49%), Prentiss Island (44%), and New Meadows River (40%). This study highlights that large and sustained surveys for parasitic diseases are fundamental for decision making toward the management of the shellfish aquaculture industry, especially for having a baseline in the case that die-offs occur.

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“…The standard curve ranged from 0 to 10 8 plasmid copies, and thus, parasite load measurements for experimental samples were expressed as the (log) number of copies of P. marinus DNA detected in 100 ng of DNA extract, averaged across two replicates. To better relate these values to previously published parasite loads in the eastern oyster, P. marinus concentrations were determined in a set of 100 oysters with a wide range of infection intensities using two different quantitation methods: the qPCR method described above and the whole body‐burden method (reviewed in Dungan & Bushek, ). The relationship between the two quantities was determined (Supplement 1) so parasite loads could be reported as (log) parasites g −1 wet tissue weight.…”

Section: Methodsmentioning

confidence: 99%

Defining Dermo resistance phenotypes in an eastern oyster breeding population

et al. 2019

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Perkinsus marinus, the causative agent of Dermo disease, is responsible for mass mortalities and negatively impacts aquaculture production of the eastern oyster, Crassostrea virginica. Selective breeding is a viable option for Dermo disease management; however, fluctuations in natural selection pressure and environmental noise hinder accumulation of genetic gains acquired through field performance trials. The purpose of this study was to adapt and apply laboratory disease challenge methods to eastern oysters, better characterize resistance‐specific traits and assess the potential for genetic variation in Dermo resistance among distinct families within a breeding population. Two challenge experiments were conducted, one in 2014 and the other in 2015. Significant treatment (control vs. challenged) and family effects on survival (measured as per cent survival and days to death) were detected in the 2014 challenge, while overall high survival precluded the detection of a significant family effect in the 2015 challenge. An alternate measure of resistance, parasite elimination rate, was also measured in the 2015 challenge, and this varied significantly among families. Thus, both survival and the change in parasite concentration in oyster tissues over time represent Dermo resistance phenotypes that can be measured accurately with the adapted laboratory disease challenge protocol described here. The obvious next step is to incorporate the challenge protocol in eastern oyster breeding programmes to assess whether well‐defined, accurately measured, Dermo‐resistant phenotypes result in enhanced genetic improvement for this commercially important trait.

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Development and applications of Ray’s fluid thioglycollate media for detection and manipulation of Perkinsus spp. pathogens of marine molluscs

Cited by 27 publications

References 71 publications

Combined and independent effects of hypoxia and tributyltin on mRNA expression and physiology of the Eastern oyster (Crassostrea virginica)

Combined and independent effects of hypoxia and tributyltin on mRNA expression and physiology of the Eastern oyster (Crassostrea virginica)

A qPCR-Based Survey of Haplosporidium nelsoni and Perkinsus spp. in the Eastern Oyster, Crassostrea virginica in Maine, USA

Defining Dermo resistance phenotypes in an eastern oyster breeding population

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