No-choice preference of cerotoma trifurcata (coleoptera: chrysomelidae) to potential host plants of bean pod mottle virus (Comoviridae) in Iowa

To better understand the naturally occurring host range of Bean pod mottle virus (family Comoviridae, genus Comovirus, BPMV) and its principal vector Cerotoma trifurcata (F?rster) (Coleoptera: Chrysomelidae), 18 field-collected perennial plant species were tested for the presence of BPMV. By using no-choice assays, we determined the preference of these plants by bean leaf beetle, by measuring their level of herbivory relative to soybean, Glycine max (L.). New food hosts for adult bean leaf beetles include Lespedeza capitata (Michaux), Lotus corniculatus L., Trifolium alexandrinum L., Trifolium ambiguum Bieberstein, and Trifolium incarnatum L. Desmodium illinoense Gray is discovered as a new naturally occurring host for BPMV.     

Effects of the emerald ash borer invasion on the community composition of arthropods associated with ash tree boles in Maryland,U.S.A.

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The application of GIS and spatiotemporal analyses to investigations of unusual marine mammal strandings and mortality events

In 2006–2007, an unusually high number of harbor porpoises (Phocoena phocoena) stranded along the Washington and Oregon coastlines. Spatiotemporal analyses were used to examine their ability to detect clusters of porpoise strandings during an unusual mortality event (UME) in the Pacific Northwest using stranding location data. Strandings were evaluated as two separate populations, outer coast and inland waters. The presence of global clustering was evaluated using the Knox spatiotemporal test, and the presence of local clusters was investigated using a spatiotemporal scan statistic (space–time permutation). There was evidence of global clustering, but no local clustering, supporting the hypothesis that strandings were due to more varied etiologies instead of localized causes. Further analyses at subregional levels, and concurrently assessing environmental factors, might reveal additional geographic distribution patterns. This article describes the spatial analytical tools applied in this study and how they can help elucidate the spatiotemporal epidemiology of other UMEs and assist in determining their causes. More than one spatial analytical technique should be used if the study objective is to detect and describe clustering in time and space and to generate hypotheses regarding causation of marine mammal disease and stranding events.     

Methods for the isolation of water-borne Escherichia coli O157

AIMS: To develop improved methods for the detection of Escherichia coli O157 from water and sediments. METHODS AND RESULTS: The effects of different broth enrichment media (unsupplemented tryptic soya broth, tryptic soya broth with antibiotics, and gram-negative broth), incubation durations (5 and 24 hrs), incubation temperatures (37 and 44.5 degrees C) and the use of immunomagnetic separation (IMS) on the sensitivity of E. coli O157 detection were evaluated on artificially and naturally-contaminated water and sediment samples. The sensitivity of recovery of E. coli O157 from samples was dependent upon the media composition, temperature duration of incubation and the use of IMS. CONCLUSION: Use of high temperature (44.5 degrees C) incubation for 24 hrs in unsupplemented tryptic soya broth and the use of IMS improved the sensitivity of E. coli O157 culture from water and sediment samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The methods described can be used to increase the sensitivity of E. coli O157 detection from water and sediments.     

A colorimetric assay optimization for high-throughput screening of dihydroorotase by detecting ureido groups

Dihydroorotase (DHOase) is the third enzyme in the de novo pyrimidine biosynthesis pathway and is a potential new antibacterial drug target. No target-based high-throughput screening (HTS) assay for this enzyme has been reported to date. Here, we optimized two colorimetric-based enzymatic assays that detect the ureido moiety of the DHOase substrate, carbamyl-aspartate (Ca-asp). Each assay was developed in a 40-μl assay volume using 384-well plates with a different color mix, diacetylmonoxime (DAMO)–thiosemicarbazide (TSC) or DAMO–antipyrine. The sensitivity and color interference of both color mixes were compared in the presence of common HTS buffer additives, including dimethyl sulfoxide, reducing agents, detergents, and bovine serum albumin. DAMO–TSC (Z′-factors 0.7–0.8) was determined to be superior to DAMO–antipyrine (Z′-factors 0.5–0.6) with significantly less variability within replicates. An HTS pilot screening with 29,552 compounds from four structurally diverse libraries confirmed the quality of our newly optimized colorimetric assay with DAMO–TSC. This robust method has no heating requirement, which was the main obstacle to applying previous assays to HTS. More important, this well-optimized HTS assay for DHOase, the first of its kind, should make it possible to screen large-scale compound libraries to develop new inhibitors against any enzymes that produce ureido functional groups.     

Characterization of benzodiazepine receptors with fluorescent ligands

Fluorescein conjugates of the high-affinity benzodiazepine receptor ligands Ro 15-1788 and Ro 7-1986 were synthesized. The binding of these fluorescent ligands (BD 621 and BD 607) to benzodiazepine receptors was characterized by direct fluorescence measurement. Both the equilibrium dissociation constants (KD) of BD 621 and BD 607 and the maximum number of binding sites (Bmax) estimated by fluorescence monitoring were consistent with values obtained by using radioligand binding techniques. The binding of BD 621 and BD 607 assessed by fluorescence measurement was reversible, abolished by photoaffinity labeling with Ro 15-4513, and unaffected by a variety of substances that do not bind to benzodiazepine receptors. The potencies of chemically diverse benzodiazepine receptor compounds to inhibit fluorescent ligand binding were highly correlated (r = 0.94, P less than 0.001), with potencies obtained from radioligand binding techniques. These findings demonstrate the feasibility of using direct fluorescence measurement techniques to quantitate ligand-receptor interactions.