703 research outputs found

    Potential for Electropositive Metal to Reduce the Interactions of Atlantic Sturgeon with Fishing Gear

    Full text link
    Atlantic sturgeon (Acipenser oxyrhynchus) populations have been declared either endangered or threatened under the U.S. Endangered Species Act. Effective measures to repel sturgeon from fishing gear would be beneficial to both fish and fishers because they could reduce both fishery‐associated mortality and the need for seasonal and area closures of specific fisheries. Some chondrostean fishes (e.g., sturgeons and paddlefishes) can detect weak electric field gradients (possibly as low as 5 Μv/cm) due to arrays of electroreceptors (ampullae of Lorenzini) on their snout and gill covers. Weak electric fields, such as those produced by electropositive metals (typically mixtures of the lanthanide elements), could therefore potentially be used as a deterrent. To test this idea, we recorded the behavioral responses of juvenile Atlantic sturgeon (31–43 cm fork length) to electropositive metal (primarily a mixture of the lanthanide elements neodymium and praseodymium) both in the presence and absence of food stimuli. Trials were conducted in an approximately 2.5 m diameter × 0.3 m deep tank, and fish behaviors were recorded with an overhead digital video camera. Video records were subsequently digitized (x, y coordinate system), the distance between the fish and the electropositive metal calculated, and data summarized by compiling frequency distributions with 5‐cm bins. Juvenile sturgeon showed clear avoidance of electropositive metal but only when food was present. On the basis of our results, we conclude that the electropositive metals, or other sources of weak electric fields, may eventually be used to reduce the interactions of Atlantic sturgeon with fishing gear, but further investigation is needed. El Potencial del Metal Electropositivo para Reducir las Interacciones del Esturión Atlántico con Instrumentos de Pesca Bouyoucos, Bushnell & Brill 13–003 Resumen Las poblaciones del esturión atlántico ( Acipenser oxyrhynchus ) han sido declaradas como en peligro o amenazadas bajo el Acta de Especies en Peligro de los Estados Unidos. Las medidas efectivas para repeler a los esturiones de los instrumentos de pesca serían benéficas para los peces y los pescadores ya que podrían reducir la mortalidad asociada a la pesca y la necesidad de los cierres temporales y de área de pesquerías específicas. Algunos peces chondrosteos (p. ej.: esturiones y peces espátula) pueden detectar gradientes débiles de campos eléctricos (posiblemente tan bajos como 5 μV cm −1 ) debido a grupos de electroreceptores (ámpulas de Lorenzini) en su hocico y opérculos. Los campos eléctricos débiles, como aquellos producidos por metales electropositivos (comúnmente mezcla de elementos lantánidos), podrían entonces ser usados potencialmente como un disuasivo. Para probar esta idea, filmamos las respuestas conductuales de esturiones juveniles (31 – 43 cm de largo) a metales electropositivos (principalmente una mezcla de los elementos lantánidos neodimio y praseodimio) tanto en la presencia como en la ausencia de estímulos de alimento. Las pruebas se realizaron en un tanque de ≈ 2.5 metros de diámetro x 0.3 m de profundidad, y las conductas de los peces se filmaron con una cámara digital de video colocada sobre el tanque. Las filmaciones después se digitaron (sistema de coordenadas x, y), se calculó la distancia entre los peces y el metal electropositivo y se resumió la información al compilar las distribuciones de la frecuencia con contenedores de 5 cm. Los esturiones juveniles mostraron clara evitación del metal electropositivo pero sólo cuando el alimento estaba presente. Basándonos en nuestros resultados, concluimos que los metales electropositivos, u otras fuentes de campos eléctricos débiles, puede ser usada eventualmente para reducir las interacciones del esturión atlántico con los instrumentos de pesca, pero es necesario llevar a cabo más investigaciones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102646/1/cobi12200.pd

    Sequential Grazing Systems for Beef Cattle Production

    Get PDF
    Pasture productivity in Iowa is often limited by low productivity of cool-season grasses during summer. This uneven seasonal distribution of for age production could be improved by including species in pasture systems that perform better under higher temperatures. Warm-season grasses produce most of their growth during summer when cool-season grasses are semi -dormant. By using cool-season and warm-season pastures in a sequential system it should be possible to improve seasonal productivity. The overall objective of this project i s to evaluate the productivity of sequential grazing system s for beef cattle production in Southern Iowa. Specific objectives are to: 1) evaluate the impact of legumes on the productivity of cool-season pastures grazed in the spring and fall, 2) evaluate warm-season grasses f or summer grazing, and 3) determine the effects of pasture sequence on the productivity of season-long grazing systems

    Identification and characterization of Cercospora beticola necrosis-inducing effector CbNip1

    Get PDF
    Cercospora beticola is a hemibiotrophic fungus that causes cercospora leaf spot disease of sugar beet (Beta vulgaris). After an initial symptomless biotrophic phase of colonization, necrotic lesions appear on host leaves as the fungus switches to a necrotrophic lifestyle. The phytotoxic secondary metabolite cercosporin has been shown to facilitate fungal virulence for several Cercospora spp. However, because cercosporin production and subsequent cercosporin‐initiated formation of reactive oxygen species is light‐dependent, cell death evocation by this toxin is only fully ensured during a period of light. Here, we report the discovery of the effector protein CbNip1 secreted by C. beticola that causes enhanced necrosis in the absence of light and, therefore, may complement light‐dependent necrosis formation by cercosporin. Infiltration of CbNip1 protein into sugar beet leaves revealed that darkness is essential for full CbNip1‐triggered necrosis, as light exposure delayed CbNip1‐triggered host cell death. Gene expression analysis during host infection shows that CbNip1 expression is correlated with symptom development in planta. Targeted gene replacement of CbNip1 leads to a significant reduction in virulence, indicating the importance of CbNip1 during colonization. Analysis of 89 C. beticola genomes revealed that CbNip1 resides in a region that recently underwent a selective sweep, suggesting selection pressure exists to maintain a beneficial variant of the gene. Taken together, CbNip1 is a crucial effector during the C. beticola–sugar beet disease process

    Sequential Grazing of Cool- and Warm-Season Pastures

    Get PDF
    Pasture productivity in Iowa often is limited by low productivity of cool-season grasses during summer. This uneven seasonal distribution of forage production could be improved by including species in pasture systems that perform better under higher temperatures. Warm-season grasses produce most of their growth during summer when cool-season grasses are semi-dormant. By using cool-season and warm-season pastures in a sequential system, it should be possible to improve seasonal productivity

    Survey of bacterial diversity in chronic wounds using Pyrosequencing, DGGE, and full ribosome shotgun sequencing

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Chronic wound pathogenic biofilms are host-pathogen environments that colonize and exist as a cohabitation of many bacterial species. These bacterial populations cooperate to promote their own survival and the chronic nature of the infection. Few studies have performed extensive surveys of the bacterial populations that occur within different types of chronic wound biofilms. The use of 3 separate16S-based molecular amplifications followed by pyrosequencing, shotgun Sanger sequencing, and denaturing gradient gel electrophoresis were utilized to survey the major populations of bacteria that occur in the pathogenic biofilms of three types of chronic wound types: diabetic foot ulcers (D), venous leg ulcers (V), and pressure ulcers (P).</p> <p>Results</p> <p>There are specific major populations of bacteria that were evident in the biofilms of all chronic wound types, including <it>Staphylococcus, Pseudomonas, Peptoniphilus, Enterobacter, Stenotrophomonas, Finegoldia</it>, and <it>Serratia </it>spp. Each of the wound types reveals marked differences in bacterial populations, such as pressure ulcers in which 62% of the populations were identified as obligate anaerobes. There were also populations of bacteria that were identified but not recognized as wound pathogens, such as <it>Abiotrophia para-adiacens </it>and <it>Rhodopseudomonas </it>spp. Results of molecular analyses were also compared to those obtained using traditional culture-based diagnostics. Only in one wound type did culture methods correctly identify the primary bacterial population indicating the need for improved diagnostic methods.</p> <p>Conclusion</p> <p>If clinicians can gain a better understanding of the wound's microbiota, it will give them a greater understanding of the wound's ecology and will allow them to better manage healing of the wound improving the prognosis of patients. This research highlights the necessity to begin evaluating, studying, and treating chronic wound pathogenic biofilms as multi-species entities in order to improve the outcomes of patients. This survey will also foster the pioneering and development of new molecular diagnostic tools, which can be used to identify the community compositions of chronic wound pathogenic biofilms and other medical biofilm infections.</p

    Oral Bromelain Attenuates Inflammation in an Ovalbumin-induced Murine Model of Asthma

    Get PDF
    Bromelain, a widely used pineapple extract with cysteine protease activity, has been shown to have immunomodulatory effects in a variety of immune system models. The purpose of the present study was to determine the effects of orally administered bromelain in an ovalbumin (OVA)-induced murine model of acute allergic airway disease (AAD). To establish AAD, female C57BL/6J mice were sensitized with intraperitoneal (i.p.) OVA/alum and then challenged with OVA aerosols for 3 days. Mice were gavaged with either (phosphate buffered saline)PBS or 200 mg/kg bromelain in PBS, twice daily for four consecutive days, beginning 1 day prior to OVA aerosol challenge. Airway reactivity and methacholine sensitivity, bronchoalveolar lavage (BAL) cellular differential, Th2 cytokines IL-5 and IL-13, and lung histology were compared between treatment groups. Oral bromelain-treatment of AAD mice demonstrated therapeutic efficacy as evidenced by decreased methacholine sensitivity (P ≤ 0.01), reduction in BAL eosinophils (P ≤ 0.02) and IL-13 concentrations (P ≤ 0.04) as compared with PBS controls. In addition, oral bromelain significantly reduced BAL CD19+ B cells (P ≤ 0.0001) and CD8+ T cells (P ≤ 0.0001) in AAD mice when compared with controls. These results suggest that oral treatment with bromelain had a beneficial therapeutic effect in this murine model of asthma and bromelain may also be effective in human conditions

    Control and elimination of schistosomiasis as a public health problem: thresholds fail to differentiate schistosomiasis morbidity prevalence in children

    Get PDF
    BACKGROUND: Current World Health Organization guidelines utilize prevalence of heavy-intensity infections (PHIs), that is, ≥50 eggs per 10 mL of urine for Schistosoma haematobium and ≥400 eggs per gram of stool for S. mansoni, to determine whether a targeted area has controlled schistosomiasis morbidity or eliminated schistosomiasis as a public health problem. The relationship between these PHI categories and morbidity is not well understood. METHODS: School-age participants enrolled in schistosomiasis monitoring and evaluation cohorts from 2003 to 2008 in Burkina Faso, Mali, Niger, Tanzania, Uganda, and Zambia were surveyed for infection and morbidity at baseline and after 1 and 2 rounds of preventive chemotherapy. Logistic regression was used to compare morbidity prevalence among participants based on their school's PHI category. RESULTS: Microhematuria levels were associated with the S. haematobium PHI categories at all 3 time points. For any other S. haematobium or S. mansoni morbidity that was measured, PHI categories did not differentiate morbidity prevalence levels consistently. CONCLUSIONS: These analyses suggest that current PHI categorizations do not differentiate the prevalence of standard morbidity markers. A reevaluation of the criteria for schistosomiasis control is warranted

    Defining elimination as a public health problem for schistosomiasis control programmes: beyond prevalence of heavy-intensity infections

    Get PDF
    WHO's 2021?30 road map for neglected tropical diseases (NTDs) outlines disease-specific and cross-cutting targets for the control, elimination, and eradication of NTDs in affected countries. For schistosomiasis, the criterion for elimination as a public health problem (EPHP) is defined as less than 1% prevalence of heavy-intensity infections (ie, ≥50 Schistosoma haematobium eggs per 10 mL of urine or ≥400 Schistosoma mansoni eggs per g of stool). However, we believe the evidence supporting this definition of EPHP is inadequate and the shifting distribution of schistosomiasis morbidity towards more subtle, rather than severe, morbidity in the face of large-scale control programmes requires guidelines to be adapted. In this Viewpoint, we outline the need for more accurate measures to develop a robust evidence-based monitoring and evaluation framework for schistosomiasis. Such a framework is crucial for achieving the goal of widespread EPHP of schistosomiasis and to meet the WHO road map targets. We encourage use of overall prevalence of schistosome infection (instead of the prevalence of heavy-intensity infections), development of species-dependent and age-dependent morbidity markers, and construction of a standardised monitoring and evaluation protocol

    Schistosoma mansoni Enhances Host Susceptibility to Mucosal but Not Intravenous Challenge by R5 Clade C SHIV

    Get PDF
    Parasitic infections have been postulated to increase host susceptibility to HIV-1. We previously demonstrated that rhesus monkeys with active schistosomiasis were significantly more likely to become systemically infected after intrarectal exposure to an R5-tropic clade C simian-human immunodeficiency virus then were parasite-free control animals. However, we could not address whether parasites exert their effect at the mucosal level or systemically. To address the latter possibility, we measured the virus doses needed to achieve systemic infection after intravenous exposure of parasite-free or parasite-positive monkeys using the identical virus stock. None of the viral parameters tested in these two groups of monkeys were statistically significantly different. These results suggest that schistosomiasis modulates susceptibility to immunodeficiency virus acquisition predominantly at the mucosal level. Treatment for parasitic infections in populations at higher risk for HIV-1 acquisition could represent a cost-effective approach to slow the spread of HIV-1, which is predominantly transmitted through mucosal routes
    corecore