792 research outputs found

    Buffering and the Reproduction Right: When is a Copy a Copy?

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    From Registration to Recounts Revisited: Developments in the Election Ecosystems of Five Midwestern States

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    As a follow-up to a study of problems during the 2006 elections, examines the states' continuing adjustments to institutional arrangements, voter registration databases, convenience voting, and post-election processes in the 2008 elections

    Characterization of Monoclonal Antibodies to Avian Escherichia coli Iss

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    Colibacillosis accounts for annual multimillion dollar losses in the poultry industry, and control of this disease is hampered by limited understanding of the virulence mechanisms used by avian pathogenic Escherichia coli (APEC). Previous work in our laboratory has found that the presence of the increased serum survival gene (iss) is strongly associated with APEC but not commensal E. coli, making iss and the protein it encodes (Iss) candidate targets of colibacillosis-control procedures. Previously, we produced monoclonal antibodies (MAbs) against Iss to be used as a reagent in studies of APEC virulence and colibacillosis pathogenesis. Unfortunately, the utility of these MAbs was limited because these MAbs exhibited nonspecific binding. It was thought that the lack of specificity might be related to the fact that these MAbs were of the immunoglobulin M (IgM) isotype. In the present study, new MAbs were produced using a different immunization strategy in an effort to generate MAbs of a different isotype. Also, because Iss bears strong similarity to Bor, a lambda-derived protein that occurs commonly among E. coli, MAbs were assessed for their ability to distinguish Iss and Bor. For these studies, the bor gene from an APEC isolate was cloned into an expression vector. The fusion protein expressed from this construct was used to assess the potential of the anti-Iss MAbs produced in the past and present studies to distinguish Bor and Iss. The MAbs produced in this study were of the IgG1 isotype, which appeared to bind more specifically to Iss than previously generated antibodies in certain immunologic procedures. These results suggested that the MAbs generated in this study might prove superior to the previous MAbs as a reagent for study of APEC. However, both MAbs recognized recombinant Iss and Bor, suggesting that any results obtained using anti-Iss MAbs would need to be interpreted with this cross-reactivity in mind

    Immune Response to Recombinant Escherichia coli Iss Protein in Poultry

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    Colibacillosis accounts for significant losses to the poultry industry, and control efforts are hampered by limited understanding of the mechanisms used by avian pathogenic Escherichia coli (APEC) to cause disease. We have found that the presence of the increased serum survival gene (iss) is strongly associated with APEC but not with commensal E. coli, makingiss, and the protein it encodes (Iss), candidate targets of colibacillosis control procedures. To assess the potential of Iss to elicit a protective response in chickens against APEC challenge, Iss fusion proteins were produced and administered subcutaneously to four groups of 2-wk-old specific-pathogen-free leghorn chickens. At 4 wk postimmunization, birds were challenged with APEC from serogroups O2 and O78 via intramuscular injection. At 2 wk postchallenge, birds were necropsied, and lesions consistent with colibacillosis were scored. Also, sera were collected from the birds pre- and postimmunization, and antibody titers to Iss were determined. Immunized birds produced a humoral response to Iss, and they had significantly lower lesion scores than the unimmunized control birds following challenge with both APEC strains. Birds that received the smallest amount of immunogen had the lowest lesion scores. Although further study will be needed to confirm the value of Iss as an immunoprotective antigen, these preliminary data suggest that Iss may have the potential to elicit significant protection in birds against heterologous E. coli challenge

    Proficiency testing of laboratories for paralytic shellfish poisoning toxins in shellfish by QUASIMEME: A review

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    AbstractParalytic Shellfish Poisoning (PSP) toxins are some of the most toxic substances known to man and consumption of shellfish containing these naturally-occurring neurotoxins can lead to a range of different symptoms including death in extreme cases. It is imperative therefore, to implement robust shellfish monitoring programs to minimise the possibility of contaminated product reaching the marketplace. To improve the quality assurance of these programs, QUASIMEME, the proficiency test provider added to its scope PSP toxins in shellfish. Since 2009, six proficiency testing exercises have been delivered by QUASIMEME with a total of thirty-four different laboratories submitting data using a range of different methods. These include animal and antibody based assays, together with High Performance Liquid Chromatography (HPLC) techniques using post and pre-column oxidation and more recently LC-MS/MS methodologies.Data from these exercises is presented and laboratory performance is assessed to determine any changes in overall performance over the six rounds, together with any potential method-related performance issues. The data showed the improvement of laboratories over the six exercises with between laboratory CV% values decreasing from an average of 39% in the first year to 22% in 2014 and the average percentage of participants receiving satisfactory z-scores increasing from 50% in 2009 to over 66% in 2014
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