369 research outputs found

    Equine Piroplasmosis Domestic Pathways Assessment (2011)

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    Abstract: Equine piroplasmosis (EP) is a tick borne disease of equids. It is considered a foreign animal disease in the United States. However, from January 2009 through November 2010, 542 confirmed positive cases have been identified in 16 different States. This domestic pathways assessment evaluates the risk of releasing an EP pathogen (Theileria equi or Babesia caballi) from a quarantined premises through movement of horses. In addition, this assessment evaluates the risk of disease transmission by ticks, vertical transmission, or iatrogenic transmission. When an acaricide is applied correctly, the risk of EP transmission by ticks to a horse is low. In addition, infected reservoir hosts, environmental factors, and competent vectors must be present for the disease transmission cycle to occur. Vertical transmission of T. equi is considered a moderate risk pathway and the risk of vertical transmission of B. caballi is negligible. Iatrogenic transmission via whole blood transfusion, blood doping, commercial serum/blood plasma, and contaminated equipment poses the highest risk of disease transmission. Blood is an efficient vehicle of transmission for EP pathogens and even a small volume of blood can be infectious. Exposure of an uninfected horse to any of these pathways is likely to result in EP transmission. Iatrogenic exposure may be difficult to regulate. Management practices such as testing blood donors would help mitigate this risk but these practices vary throughout the equine industry. The overall risk of EP spread by the movement of a horse from a quarantined premises is moderate

    A guide to the contained use of plant virus infectious clones

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    Plant virus infectious clones are important tools with wide-ranging applications in different areas of biology and medicine. Their uses in plant pathology include the study of plant–virus interactions, and screening of germplasm as part of prebreeding programmes for virus resistance. They can also be modified to induce transient plant gene silencing (Virus Induced Gene Silencing – VIGS) and as expression vectors for plant or exogenous proteins, with applications in both plant pathology and more generally for the study of plant gene function. Plant viruses are also increasingly being investigated as expression vectors for in planta production of pharmaceutical products, known as molecular farming. However, plant virus infectious clones may pose a risk to the environment due to their ability to reconstitute fully functional, transmissible viruses. These risks arise from both their inherent pathogenicity and the effect of any introduced genetic modifications. Effective containment measures are therefore required. There has been no single comprehensive review of the biosafety considerations for the contained use of genetically modified plant viruses, despite their increasing importance across many biological fields. This review therefore explores the biosafety considerations for working with genetically modified plant viruses in contained environments, with focus on plant growth facilities. It includes regulatory frameworks, risk assessment, assignment of biosafety levels, facility features and working practices. The review is based on international guidance together with information provided by plant virus researchers

    Phyllosticta citricarpa and sister species of global importance to Citrus.

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    Several Phyllosticta species are known as pathogens of Citrus spp., and are responsible for various disease symptoms including leaf and fruit spots. One of the most important species is P. citricarpa, which causes a foliar and fruit disease called citrus black spot. The Phyllosticta species occurring on citrus can most effectively be distinguished from P. citricarpa by means of multilocus DNA sequence data. Recent studies also demonstrated P. citricarpa to be heterothallic, and reported successful mating in the laboratory. Since the domestication of citrus, different clones of P. citricarpa have escaped Asia to other continents via trade routes, with obvious disease management consequences. This pathogen profile represents a comprehensive literature review of this pathogen and allied taxa associated with citrus, focusing on identification, distribution, genomics, epidemiology and disease management. This review also considers the knowledge emerging from seven genomes of Phyllosticta spp., demonstrating unknown aspects of these species, including their mating behaviour.TaxonomyPhyllosticta citricarpa (McAlpine) Aa, 1973. Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Botryosphaeriales, Family Phyllostictaceae, Genus Phyllosticta, Species citricarpa.Host rangeConfirmed on more than 12 Citrus species, Phyllosticta citricarpa has only been found on plant species in the Rutaceae.Disease symptomsP. citricarpa causes diverse symptoms such as hard spot, virulent spot, false melanose and freckle spot on fruit, and necrotic lesions on leaves and twigs.Useful websitesDOE Joint Genome Institute MycoCosm portals for the Phyllosticta capitalensis (https://genome.jgi.doe.gov/Phycap1), P. citriasiana (https://genome.jgi.doe.gov/Phycit1), P. citribraziliensis (https://genome.jgi.doe.gov/Phcit1), P. citrichinaensis (https://genome.jgi.doe.gov/Phcitr1), P. citricarpa (https://genome.jgi.doe.gov/Phycitr1, https://genome.jgi.doe.gov/Phycpc1), P. paracitricarpa (https://genome.jgi.doe.gov/Phy27169) genomes. All available Phyllosticta genomes on MycoCosm can be viewed at https://genome.jgi.doe.gov/Phyllosticta

    Insuring Against Losses from Transgenic Contamination: The Case of Pharmaceutical Maize

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    Concerns about the risk of food supply contamination and the resulting financial losses have limited the development and commercialization of certain pharmaceutical plants. This article develops an insurance pricing model that helps translate these concerns into a cost-benefit analysis. The model first estimates the physical dispersal of maize pollen subject to a number of weather parameters. This distribution is then validated with the limited amount of currently available field trial data. The physical distribution is then used to calculate the premium for a fair-valued insurance policy that would fund the destruction of possibly contaminated fields. The flexible framework can be readily adapted to other crops, management practices, and regions

    Using Noninvasive Genetics for Estimating Density and Assessing Diet of Urban and Rural Coyotes in Florida, USA

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    Coyotes (Canis latrans) are expanding their range and due to conflicts with the public and concerns of Coyotes affecting natural resources such as game or sensitive species, there is interest and often a demand to monitor Coyote populations. A challenge to monitoring is that traditional invasive methods involving live-capture of individual animals are costly and can be controversial. Natural resource management agencies can benefit from contemporary noninvasive genetic sampling approaches aimed at determining key aspects of Coyote ecology (e.g., population density and food habits). However, the efficacy of such approaches under different environmental conditions is poorly understood. Our objectives were to 1) examine accumulation and nuclear DNA degradation rates of Coyote scats in metropolitan and rural sites in Florida to help optimize methods to estimate population density; and 2) explore new genetic methods for determining diet of Coyotes based on vertebrate, plant, and invertebrate species DNA identified in scat. Recently developed DNA metabarcoding approaches make it possible to simultaneously identify DNA from multiple prey species in predator scat samples, but an exploration of this tool for assessing Coyote diet has not been pursued. We observed that scat accumulation rates (0.02 scats/km/day) did not vary between sites and fecal DNA amplification success decreased and genotyping errors increased over time with exposure to sun and precipitation. DNA sampling allowed us to generate a Coyote density estimate for the urban environment of eight Coyotes per 100 km2, but lack of recaptures in the rural area precluded density estimation. DNA metabarcoding showed promise for assessing diet contributions of vertebrate species to Coyote diet. Feral Swine (Sus scrofa) were detected as prey at higher frequencies than previously reported. We identify several considerations that can be used to optimize future noninvasive sampling efforts for Coyotes in the southeastern United States. We also discuss strengths and drawbacks of utilizing DNA metabarcoding for assessing diet of generalist carnivores such as Coyotes

    The effects of postharvest carbon dioxide and a cold storage treatment on Tuta absoluta mortality and tomato fruit quality

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    Tuta absoluta is an invasive pest species that affects tomatoes and other solanaceous crops and is found in Europe and other Mediterranean areas. Hitherto, fumigation with methyl bromide is the only measure used to control this pest during the postharvest period. Because of methyl bromide phytotoxicity and health, safety and environmental concerns, alternatives to this product need to be investigated. Therefore, the objective of this study was to determine the ability of T. absoluta to complete its preimaginal development on tomato fruit during the postharvest period and to evaluate the effectiveness of different supra atmospheric carbon dioxide (CO2) levels and cold storage treatments on T. absoluta control. T. absoluta was unable to complete its development from egg to adult on fruit of three tomato varieties. In contrast, T. absoluta completed its preimaginal development when more mature larvae were provided with the tomato fruit. The exposure of T. absoluta to a modified atmosphere of 95% CO2 at 25 °C for 48 h was effective for the control of all life stages, but negatively affect fruit quality. An increment in the exposure time to 72 h was necessary in order to obtain the same level of control at 40% CO2. A cold storage treatment at 1 °C for a total of 10 days was also effective for the control of the T. absoluta eggs. These two treatments did not negatively affect the quality of the fruit. Therefore, these appear to be effective alternatives to postharvest methyl bromide fumigation and future studies need to be planned to validate the commercial feasibility of these findings

    Maize x Teosinte Hybrid Cobs Do Not Prevent Crop Gene Introgression

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    Maize x Teosinte Hybrid Cobs Do Not Prevent Crop Gene Introgression. Whether introgression from crops to wild relatives can occur is an important component of transgene risk assessment. In the case of maize, which co-occurs with its wild relative teosinte in Mexico, the possibility of introgression has been controversial. Maize is cross-compatible with teosinte, and spontaneous hybridization is known to occur. Some scientists have hypothesized that the maize x teosinte cob infructescence will prevent progeny dispersal, thus preventing introgression. Motivated by a prior study where we found maize x teosinte hybrid fruits naturally dispersed under field conditions, we tested whether hybrid cobs hold their fruits as tightly as maize cobs. We found the force required to detach hybrid fruits was substantially and significantly less than that for maize. Consequently, we expect that introgression of transgenes from maize into teosinte in Mexico should occur largely unimpeded by the hybrid cob.La mazorca o elote híbrido de maíz x teocintle no impide la introgresión de genes transgénicos provenientes del cultivo. La introgresión entre el maíz cultivado y el maíz silvestre, o teocintle, es un componente importante en la evaluación ambiental relacionada con los riesgos de la introducción de genes transgénicos. La posibilidad de introgresión entre el maíz domesticado y el teocintle ha sido un tema controversial, en particular en México, donde maíz y teocintle coexisten. El maíz es compatible con el teocintle y la hibridización espontánea ocurre entre ellos. Algunos científicos han planteado como hipótesis que al cruzar el maíz con teocintle, la estructura interna de la infrutescencia que sujeta los frutos conocida como la mazorca de maíz o el elote, impide la dispersión de la progenie evitando que la introgresión ocurra. Los resultados de un estudio previo evidencian la dispersión de los frutos híbridos del maíz x teocintle en condiciones naturales. Motivados por estos resultados, hemos decidido investigar si la mazorca o el elote de las infrutescencias del híbrido sujetan los frutos con una fuerza comparable o mayor a la del maíz. Nuestras mediciones implican que la fuerza necesaria para liberar los frutos híbridos son substancial y significativamente menores que aquellas necesarias para desprender los frutos del maíz. Como conclusión sugerimos que en México, la mazorca o el elote no representan una barrera que impida la introgresión de los genes transgénicos del maíz al teocintle
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