645 research outputs found

    Advanced Perkinsus Marinus Infections In Crassostrea Ariakensis Maintained Under Laboratory Conditions

    Get PDF
    The Suminoe oyster, Crassostrea ariakensis, has been under investigation since the early 1990s for potential use in restoring the commercial harvest or for aquaculture of oysters in the Chesapeake Bay, USA. Initial studies focusing on C. ariakensis documented a significant level of tolerance to the protozoan parasite Perkinsus marinus, a pathogen found in almost all reaches of the Bay and widely acknowledged as one of the main reasons for the decline in the eastern oyster, Crassostrea virginica, harvest since the late 1980s. Crassostrea ariakensis was demonstrated to acquire P. marinus. however infection intensities, as measured using Ray\u27s thioglycollate medium assay indices, generally were found to be light. As part of a series of experiments to study potential impacts on the Chesapeake Bay region of pathogens found in C. ariakensis in Asia, a challenge experiment was conducted to study the pathogenicity of Perkinsus olseni to C. ariakensis. During this study, we observed the acquisition of moderate and heavy infection intensities of P. marinus in triploid C. ariakensis oysters being maintained in the laboratory. Results suggest that there may be some risk of mortality from P. marinus if C. ariakensis is held under stressful conditions at least in hatchery or laboratory settings

    Genetic Diversity In U.S. Hatchery Stocks Of Crassostrea Ariakensis (Fujita, 1913) And Comparison With Natural Populations In Asia

    Get PDF
    Although several different U.S. hatchery stocks of the Asian Suminoe oyster Crassosirea ariakensis were used in laboratory and field trials assessing performance, and in comparative studies with the native oyster Crassostrea virginica, the genetic composition of these hatchery stocks has not yet been examined comprehensively. Using eight microsatellite markers we investigated the genetic variability among five hatchery stocks and compared the genetic makeup of these stocks with 8 wild populations from Asia. Results showed significant genetic differentiation among the 5 hatchery stocks that was 6-fold larger than that observed among wild populations. A significant reduction in genetic diversity was observed in hatchery stocks compared with wild source populations, indicating a genetic bottleneck. Two long-established stocks showed significant decreases in both allelic diversity and heterozygosity compared with the wild Japanese source population, whereas three recently established stocks showed less severe reductions in allelic diversity and a nonsignificant change in levels of heterozygosity compared with their source Chinese populations. These microsatellite markers also proved useful for assignment of hatchery individuals back to their source stocks with a high degree of confidence. Although assignment of wild individuals back to their population of origin proved less reliable, approximately 70% of wild individuals could be assigned either to their source population or to geographically proximal populations. Our results suggest that results obtained from experiments that used hatchery animals of a single C. ariakensis stock for biological and ecological studies should be interpreted cautiously, because they may not always accurately reflect the behavior of wild populations or of other hatchery stocks

    Tracking Triploid Mortalities Of Eastern Oysters Crassostrea virginica In The Virginia Portion Of The Chesapeake Bay

    Get PDF
    Since 2012, aquacultured eastern oysters Crassostrea virginica have been reported by oyster farmers to display mortality approaching 30%, and in some cases 85%, in areas of the lower Chesapeake Bay, VA. Based on accounts from industry, this mortality has typically affected 1-y-old oysters between May and early July, and has tended to occur in triploid oysters, which represent the vast bulk of production in the area. During this period, samples submitted for pathology have not revealed the presence of major pathogens as a cause. In 2015, to gain deeper insight into this mortality and determine whether specific sites, ploidy condition, or genetic lines were affected, oyster seed commercially produced in early 2014 were obtained from four lines, one diploid (2N DEBY) and three triploid (3N DEBY, 3N hANA, and 3N Northern). These lines were deployed in July 2014 at aquaculture farms at five Chesapeake Bay locations: Locklies Creek and Milford Haven on the western shore, and Pungoteague Creek, Nassawadox Creek, and Cherrystone Creek on the Eastern Shore. During this study, mortality was observed to peak in June at most sites, reaching a mean mortality across all tested lines of 17.0% and a cumulative mortality for the study period of 32.0% at Nassawadox Creek, the site most severely affected by mortality that followed the expected early summer mortality pattern. Interval mortality at all sites decreased to under 5% after June, but cumulative levels for the study period reached from 8.8% to 18.6% even at the sites least affected by mortality. This represents a high level of mortality given the documented absence of material involvement by major oyster pathogens such as Hapolosporidium nelsoni and Perkinsus marinus. Infiltration of gill tissues by hemocytes, observed in up to 33% of individuals at Nassawadox Creek coincident with the increase in mortality, was the only pathology observed. Harmful algal blooms were not associated with the mortality, nor were abnormal temperatures or salinities. There was no clear relationship of mortality to oyster genetic heritage, although there was variability in susceptibility among oyster lines and interactions between lines and specific sites. At some locations and in comparison with diploids, triploid oysters appeared to be more susceptible to mortality. Mortality in triploids was coincident with the timing of peak gametogenic development in diploids. Given the lack of involvement by major pathogens and the possible association of mortality with oyster gametogenesis, future work should seek to better understand the suite of environmental stressors potentially impacting cultured oysters in these systems and their interactions with the physiology and energetics of these animals

    Detection of toxins and harmful algal bloom cells in shellfish hatcheries and efforts toward removal

    Get PDF
    As the start of the supply chain for the aquaculture industry, hatcheries are a crucial component in the success of oyster and northern quahog (hard clam) aquaculture on the East Coast of the US. Intermittent failures in hatchery production slow industry growth and reduce profits. To begin investigations into the possible role of algal toxins in hatchery production failure, post-treatment hatchery water from one research and four commercial hatcheries in lower Chesapeake Bay, USA, was sampled for (1) toxin presence and (2) harmful algal bloom (HAB) cell enumeration. Overall, seven toxin classes, likely produced by six different HAB species, were detected in post- treatment hatchery water, despite a lack of visually identifiable HAB cells within the facility. Toxins detected include pectenotoxin-2, goniodomin A, karlotoxin-1 and karlotoxin-3, okadaic acid and dinophysistoxin-1, azaspiracid-1 and azaspiracid-2, brevetoxin-2, and microcystin-LR. In a second, more targeted study, two batches of source water were followed and sampled at each step of a water-treatment process in the VIMS Aquaculture Genetics and Breeding Technology Center research hatchery in Gloucester Point, Virginia, USA. Two treatment steps showed particular promise for decreasing the concentrations of the three toxins detected in the source water, 24-h circulation through sand filters and activated charcoal filtration. Toxin concentrations of pectenotoxin-2, 3.53 ± 0.56 pg m

    Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States

    Get PDF
    Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study. Air samples were collected from the child's bedroom for genomic DNA extraction and metagenomic analysis of bacteria and fungi using the Illumina MiSeq sequencing platform. The analysis of bacterial populations revealed no major differences between EC and AC sampling environments. The fungal populations observed in EC homes differed from AC homes. The most prevalent species discovered in AC environments belonged to the genera Cryptococcus (20%) and Aspergillus (20%). In contrast, the most common fungi identified in EC homes belonged to the order Pleosporales and included Alternaria alternata (32%) and Phoma spp. (22%). The variations in fungal populations provide preliminary evidence of the microbial burden children may be exposed to within EC environments in this region

    Tetrachloroethylene (PCE, Perc) Levels in Residential Dry Cleaner Buildings in Diverse Communities in New York City

    Get PDF
    Fugitive tetrachloroethylene (PCE, perc) emissions from dry cleaners operating in apartment buildings can contaminate residential indoor air. In 1997, New York State and New York City adopted regulations to reduce and contain perc emissions from dry cleaners located in residential and other buildings. As part of a New York State Department of Health (NYSDOH) study, indoor air perc levels were determined in 65 apartments located in 24 buildings in New York City where dry cleaners used perc on site. Sampling occurred during 2001–2003, and sampled buildings were dispersed across minority and nonminority as well as low-income and higher income neighborhoods. For the entire study area, the mean apartment perc level was 34 μg/m(3), 10-fold lower than mean apartment levels of 340–360 μg/m(3) documented before 1997. The maximum detected perc level was 5,000 μg/m(3), 5-fold lower than the maximum of 25,000 μg/m(3) documented before 1997. Despite these accomplishments, perc levels in 17 sampled apartments still exceeded the NYSDOH residential air guideline of 100 μg/m(3), and perc levels in 4 sampled apartments exceeded 1,000 μg/m(3). Moreover, mean indoor air perc levels in minority neighborhoods (75 μg/m(3)) were four times higher than in nonminority households (19 μg/m(3)) and were > 10 times higher in low-income neighborhoods (256 μg/m(3)) than in higher income neighborhoods (23 μg/m(3)). Logistic regression suitable for clustered data (apartments within buildings) indicated that perc levels on floors 1–4 were significantly more likely to exceed 100 μg/m(3) in buildings located in minority neighborhoods (odds ratio = 6.7; 95% confidence interval, 1.5–30.5) than in nonminority neighborhoods. Factors that may be contributing to the elevated perc levels detected, especially in minority and low-income neighborhoods, are being explored

    Epithelial cells in nipple aspirate fluid and subsequent breast cancer risk: A historic prospective study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Past studies have shown that women with abnormal cytology or epithelial cells in nipple aspirate fluid (NAF) have an increased relative risk (RR) of breast cancer when compared to women from whom NAF was attempted but not obtained (non-yielders). This study analyzed NAF results from a group of women seen in a breast clinic between 1970–1991 (N = 2480). Our analysis presented here is an aggregate of two sub-groups: women with questionnaire data (n = 712) and those with NAF visits beginning in 1988 (n = 238), the year in which cancer case information was uniformly collected in California.</p> <p>Methods</p> <p>Cytological classification was determined for a group of 946 women using the most abnormal epithelial cytology observed in fluid specimens. Breast cancer incidence and mortality status was determined through June 2006 using data from the California Cancer Registry, California Vital Statistics and self-report. We estimated odd ratios (ORs) for breast cancer using logistic regression analysis, adjusting for age. We analyzed breast cancer risk related to abnormality of NAF cytology using non-yielders as the referent group and breast cancer risk related to the presence or absence of epithelial cells in NAF, using non-yielders/fluid without epithelial cells as the referent group.</p> <p>Results</p> <p>Overall, 10% (93) of the 946 women developed breast cancer during the follow-up period. Age-adjusted ORs and 95% confidence intervals (C.I.) compared to non-yielders were 1.4 (0.3 to 6.4), 1.7 (0.9 to 3.5), and 2.0 (1.1 to 3.6) for women with fluid without epithelial cells, normal epithelial cells and hyperplasia/atypia, respectively. Comparing the presence or absence of epithelial cells in NAF, women with epithelial cells present in NAF were more likely to develop breast cancer than non-yielders or women with fluid without epithelial cells (RR = 1.9, 1.2 to 3.1).</p> <p>Conclusion</p> <p>These results support previous findings that 1) women with abnormal epithelial cells in NAF have an increased risk of breast cancer when compared to non-yielders or women with normal epithelial cells in NAF and 2) women with epithelial cells present in NAF have an increased risk of breast cancer when compared to non-yielders or women who had NAF without epithelial cells present.</p

    Attractiveness of a Four-component Pheromone Blend to Male Navel Orangeworm Moths

    Get PDF
    The attractiveness to male navel orangeworm moth, Amyelois transitella, of various combinations of a four-component pheromone blend was measured in wind-tunnel bioassays. Upwind flight along the pheromone plume and landing on the odor source required the simultaneous presence of two components, (11Z,13Z)-hexadecadienal and (3Z,6Z,9Z,12Z,15Z)-tricosapentaene, and the addition of either (11Z,13Z)-hexadecadien-1-ol or (11Z,13E)-hexadecadien-1-ol. A mixture of all four components produced the highest levels of rapid source location and source contact. In wind-tunnel assays, males did not seem to distinguish among a wide range of ratios of any of the three components added to (11Z,13Z)-hexadecadienal. Dosages of 10 and 100 ng of the 4-component blend produced higher levels of source location than dosages of 1 and 1,000 ng

    Explaining the willingness of public professionals to implement new policies: A policy alienation framework

    Get PDF
    Nowadays, many public policies focus on economic values, such as efficiency and client choice. Public professionals often show resistance to implementing such policies. We analyse this problem using an interdisciplinary approach. From public administration, we draw on the policy alienation concept, which consists of five dimensions: strategic powerlessness, tactical powerlessness, operational powerlessness, societal meaninglessness and client meaninglessness. These are considered as factors that influence the willingness of professionals to implement policies (change willingness - a concept drawn from the change management literature). We test this model in a survey among 478 Dutch healthcare professionals implementing a new reimbursement policy. The first finding was that perceived autonomy (operational powerlessness) significantly influenced change willingness, whereas strategic and tactical powerlessness were not found to be significant. Second, both the meaninglessness dimensions proved highly significant. We conclude that clarifying the value of a policy is important in getting professionals to willingly implement a policy, whereas their participation on the strategic or tactical levels seems less of a motivational factor. These insights help in understanding why public professionals embrace or resist the implementation of particular policies. Points for practitioners Policymakers develop public policies which, nowadays, tend to focus strongly on economic values, such as increasing efficiency or offering citizens the opportunity to choose among suppliers of public services. Public professionals, who have to implement these policies, are often reluctant to do so. This study shows that the causes of this resistance are unlikely to be found in the lack of influence these professionals have in the shaping of the policy at the national or organizational level. Rather, professionals might resist implementing policies because they do not see them as meaningful for society, or for their own clients. Therefore, policymakers should focus on this perceived meaninglessness and adopt ways to counter this, for example by intensively communicating the value associated with a policy
    corecore