Diagnostic performance of the equine IgM capture ELISA for serodiagnosis of West Nile virus infection

The objectives of these studies were to assess the diagnostic performance (sensitivity and specificity) of the IgM capture enzyme-linked immunosorbent assay (ELISA; MAC) for diagnosis of West Nile (WN) virus in horses and to examine the performance of this test by using different criteria for seropositivity. A total of 36 horses classified as WN virus infected (group 1) and 383 horses from 4 subpopulations of hoses classified as noninfected (groups 2, 3, 4, and 5) were used in the study. The sensitivity (proportion of infected horses that tested positive for WN virus IgM antibodies) and specificity (proportion of noninfected horses that tested negative) were calculated at different cutoff points by using receiver operating curve (ROC) analysis. Using a selected cutoff point = 2.0, the sensitivity and specificity of the MAC were 91.7 and 99.2%, respectively. The area under the ROC curve = 0.95 (95% confidence interval [CI], 0.89 to 1.0), suggesting that the MAC is a useful tool for diagnosis of recent WN virus exposure in horses. In fulfillment of the 2nd objective, 2 other indices were developed and these indices approached 1.0 for the AUC with smaller 95% CIs. These indices were then used to test 602 additional diagnostic samples submitted from suspect horses between 2002 and 2004. Using the standard cutoff, 194 (32%) of the horses were interpreted as positive. Utilizing newly predicted cutoff criteria from each index, additional horses were identified as positive. In conclusion, the MAC as used for identification of WN virus-diseased horses undergoing recent exposure performs reliably at the standard cutoff for seropositivity. A negative test might not completely rule out WN virus disease, but horses that test negative were most likely not exposed to WNV. Performance of the test can be further improved by investigation of other indexes of seropositivity.     

Effects of tax incentives on long-run capital formation and total factor productivity growth in the Canadian sawmilling industry

The goal of this study was to analyze effects of tax incentives on long-run dynamics of total factor productivity (TFP) growth and capital formation in the Canadian sawmilling industry over a 40-year period (1961–2000). Simulated tax incentives involved increasing capital cost allowance and investment tax credit and reducing corporate income tax. The production technology was specified as a function of capital, labor, energy, sawlogs, and a time dependent technological progress variable. A translog multilateral index number model was applied to measure and analyze TFP.Two analytical phases were followed. In the first phase, without the tax incentives, we analyzed annual levels and growth rates of TFP1; and parametrically examined effects of output growth and time dependent technology on the growth of TFP1. Over the study period, the average annual growth rate of TFP1 was 2%; and the parametric results revealed that the marginal effects of each of output growth and technological progress on TFP1 growth were highly significant. The second phase involved recalculation of the rental price of capital to estimate effects of the simulated tax incentives on capital formation and growth of TFP (= TFP2). As expected, the average annual share of capital in total cost with the tax incentives rose to 12% from 9% without the tax incentives. The average annual capital intensity also rose to real $15,263.70 with the incentives from real $10,402.91 without the incentives. Most importantly, higher capital formation, motivated by the tax incentives, raised aggregate quantity of the inputs significantly, leading to a slightly lower TFP2 than TFP1, because output was unchanged. In short, the data validated the hypothesis that tax incentives do indeed spur capital formation and TFP growth.     

Cholinergic Activity of Selected Methanesulfonate Insecticides. A Pharmacological Profile

Three previously reported methanesulfonate insecticides, 6-isobutylthio-2-pyridyl methanesulfonate ( I ) and its sulfoxide ( II ) and sulfone ( III )analogues were examined in two insect species Lucilia cuprina and Blattella germanica and in tissues from vertebrates. The results of B. germanica tests and cholinesterase assays confirmed the insecticidal activity of the compounds, with cholinesterase inhibition being the most likely mode of insecticidal action. The inactivity of the sulfide I and sulfoxide II in vertebrate in-vitro studies may indicate that conversion, in vivo, of the sulfide and sulfoxide methanesulfonates to the sulfone ( III ) is a requirement for activity. In mouse toxicity tests, matching high toxicity was observed for the alkylthio-, alkylsulfoxy- and alkylsulfone analogues indicating fast metabolic oxidation of the injected alkylthio- and alkylsulfoxy-compounds. However, in in-vitro tissue tests, the sulfone, although active, did not exhibit the characteristic pharmacological profile of the standard acetylcholinesterase inhibitor, physostigmine. The sulfone demonstrated a mixed action, with indications that it acts as an inhibitor of specific cholinesterase isozymes, or that it may modify responses at cholinoceptors.     

Immunochemical and Electrophoretic Analysis of the Modification of Wheat Proteins in Extruded Flour Products

Antibodies specific for wheat proteins were used to identify protein fractions modified during extrusion of Hard Red Spring wheat flour (14% protein) under four different combinations of extrusion conditions (18 and 24% feed moisture and 145 and 175°C die temperature). Antibody binding was assessed on immunoblots of proteins extracted from flour and extrudates separated by SDS‐PAGE. Antibodies to high molecular weight glutenin subunits (HMW‐GS) and to B‐group low molecular weight glutenin subunits (LMW‐GS) recognized intact subunits from both flour and extrudates. Antibodies to C‐group LMW‐GS had diminished binding to extruded proteins. Glutenin‐specific antibodies also recognized protein in the extrudates migrating as a smear at molecular weights higher than intact subunits, indicating cross‐linked proteins. Antibodies recognized albumins or globulins in flour but not in extrudates, evidence that these fractions undergo significant modification during extrusion. Acid‐PAGE and antibody reaction of gliadins extracted in 1M urea and in 70% ethanol revealed total loss of cysteine‐containing α, β, γ‐gliadins but no obvious effects on sulfur‐poor ω‐gliadins, suggesting gliadin modification involves replacing intramolecular disulfides with intermolecular disulfide cross‐links. Identifying protein fractions modified during different extrusion conditions may provide new options for tailoring extrusion to achieve specific textural characteristics.     

Impacts of Plant Community Changes on Soil Carbon Contents in Northeastern Illinois

Land-cover changes not only affect regional climates through alteration in surface energy and water balance, but also affect key ecological processes, such as carbon (C) cycling and sequestration in plant ecosystems. The object of this study was to investigate the effects of land-cover changes on the distribution of soil organic carbon (SOC) contents under four plant community types (deciduous forests, pine forests, mixed pine-deciduous forests, and prairies) in northeastern Illinois, USA. Soil samples were collected from incremental soil depths (0–10, 10–20, 20–30, and 30–50 cm) under the studied plant communities. The results showed that SOC concentration decreased with increases of soil depth in the studied forests and prairies. No significant differences of SOC concentrations were found at the upper soil layers (0–10 cm) among the four plant types. However, SOC concentrations were statistically higher at the lower soil depth (30–40 cm) in prairies than in other three forest types. The SOC storage (0–40 cm soil depth) was reduced in an order prairies (250.6) > mixed pine-deciduous forests (240.7) > pine forests (190.1) > deciduous forests (163.4 Mg/ha). The characteristics of relative short life cycle, restively high turnover rate of roots, and large partition of photosynthetic production allocated to belowground were likely attributed to the higher accumulation of C in soils in tallgrass prairies than in forests. Our data indicated the conversion of native tallgrass prairies to pure forest plantations resulted in a considerable decline of SOC storage. Results suggest that land-cover changes have a significant impact on SOC storage and sequestration in plant ecosystems.     

凯伦·杨:让房子成为自己真正的家

你还在想怎样给生活添加点什么新奇的风格,让它不至于太过平淡吗?或许凯伦·杨可以帮到你,她最擅长的就是给中规中矩的房间里添加一点迷人的活力,让你的房子看上去是你自己真正的家。     

Characterization of free amino acid QTLs in maize opaque2 recombinant inbred lines

The opaque2 (o2) mutation in maize (Zea mays L.) increases the content of free amino acids (FAA) in the endosperm. We investigated the basis of this trait by using recombinant inbred lines from a cross of Oh545o2 (high FAA) and Oh51Ao2 (low FAA) to identify quantitative trait loci (QTL) for FAA content and to determine their effect on FAA composition and protein accumulation. Mapping identified six QTLs that accounted for 71% of the phenotypic variation. Two QTLs in bins 4.01 and 7.02 are close to α-zein genes; high FAA individuals with these QTLs had reduced accumulation of α-zein 19 kDa isoforms and increased FAA abundant in α-zeins. A QTL in bin 3.03 is close to a gene encoding triose phosphate isomerase (tpi4) and a higher expression of this enzyme was found in high FAA individuals. Other differentially expressed proteins included vicilin-like globulins and the enzymes glyceraldehyde-3-phosphate dehydrogenase, enolase-2, sorbitol dehydrogenase and granule-bound starch synthase. The results suggest that the increased levels of FAA in o2 endosperm are mainly due to the reduction of storage proteins and the failure to incorporate their amino acids into other proteins, as well as the alteration of carbohydrate metabolism that may favor amino acid biosynthesis.     

Identification of the vascular plants of Churchill,Manitoba, using a DNA barcode library

Background

Using phylogenies in community ecology is now commonplace, but typically, studies assume and test for a single common phylogenetic signal for all species in a community, at a given scale. A possibility that remains little-explored is that species differing in demographic or ecological attributes, or facing different selective pressures, show different community phylogenetic patterns, even within the same communities. Here I compare community phylogenetic patterns for fire-killed and fire-resistant Banksia species in the fire-prone shrublands of southwest Australia.

Results

Using new Bayesian phylogenies of Banksia, together with ecological trait data and abundance data from 24 field sites, I find that fire regeneration mode influences the phylogenetic and phenotypic signal of species co-occurrence patterns. Fire-killed species (reseeders) show patterns of phylogenetic and phenotypic repulsion consistent with competition-driven niche differentiation, but there are no such patterns for fire-resistant species (resprouters). For pairs of species that differ in fire response, co-occurrence is mediated by environmental filtering based on similarity in edaphic preferences.

Conclusions

These results suggest that it may be simplistic to characterize an entire community by a single structuring process, such as competition or environmental filtering. For this reason, community analyses based on pairwise species co-occurrence patterns may be more informative than those based on whole-community structure metrics.