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Raul Narciso C. Guedes Srinivas Kambhampati Barry A. Dover 《Entomologia Experimentalis et Applicata》1997,84(1):49-57
The lesser grain borer (Rhyzopertha dominica (F.)) is an important pest of stored grain in many parts of the world (Paleartic, Ethiopian, Oriental, Australian, Neotropical, and Neartic regions) with the ability to fly long distances. These insects have been shown to be resistant to organophosphorus insecticides in several studies. Polyacrylamide gel electrophoresis was used to assess the genetic variability within and among eight Brazilian and seven United States populations of R. dominica and to determine how insecticide resistance may be spreading within both countries. Significant variation in allele frequency among populations was observed at all six polymorphic enzyme loci that were examined. The Brazilian and U.S. populations were genetically differentiated from one another; populations within the U.S. and those within Brazil were also differentiated from one another. The mean genetic similarity among the seven U.S. populations collected in a small region in northeast Kansas was smaller than that among eight Brazilian populations collected in a relatively large geographical area. These results are consistent with the resistance ratios to chlorpyriphos-methyl in R. dominica populations from Brazil and the U.S. and the information available concerning patterns of flight activity in this insect. 相似文献
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The importance of shelter for butterflies in open landscapes 总被引:2,自引:0,他引:2
In Britain, much emphasis has been placed on conserving butterfly species in specialized habitats, since this is where most of its threatened butterflies exist, whilst the wider countryside has been largely overlooked. However, there is increasing awareness that small improvements to the dominant landscape could potentially reap huge benefits to the populations of many of Britains butterfly species. Recent studies have also stressed the importance of the landscape scale in the conservation of butterflies in small fragmented habitats. In this paper, we examine data from a variety of sources and conclude that the importance of shelter in open landscapes may be underestimated since recording is often restricted to the optimum conditions suggested by the Butterfly Monitoring Scheme. In less favourable conditions, butterflies may place greater reliance on those components of the landscape offering shelter. In light of the current policy of agricultural de-intensification we discuss how modifications to our current landscapes could benefit a wide range of species. 相似文献
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Hyalinoecia artifex: Field notes on a charismatic and abundant epifaunal polychaete on the US Atlantic continental margin
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Kirstin S. Meyer Jamie K.S. Wagner Bernard Ball Phillip J. Turner Craig M. Young Cindy L. Van Dover 《Invertebrate Biology》2016,135(3):211-224
Hyalinoecia artifex is an abundant species on the US Atlantic margin, although little is known about its behavior, ecology, or reproduction. We provide field notes and high‐resolution in situ imagery of this species observed and collected in 2013 and 2015. Hyalinoecia artifex occurred primarily on soft sediment at a density of 10.9±0.95 individuals m?2 (mean±standard error). Although they were found adjacent to mussel beds associated with methane seeps, worms were negatively associated with authigenic carbonate and other epibenthic megafauna in the study area. Quill worms moved across the sediment by extending their heads from the tubes and dragging the tubes forward. Stable isotope analysis indicated that H. artifex is a secondary consumer. Most individuals collected in 2015 were ripe, with mature oocytes up to 400 μm. Oocytes were yolky, yellow in color and positively buoyant; no brooding was observed. 相似文献
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Alderwick LJ Dover LG Veerapen N Gurcha SS Kremer L Roper DL Pathak AK Reynolds RC Besra GS 《Protein expression and purification》2008,58(2):332-341
The arabinogalactan (AG) component of the mycobacterial cell wall is an essential branched polysaccharide which tethers mycolic acids (m) to peptidoglycan (P), forming the mAGP complex. Much interest has been focused on the biosynthetic machinery involved in the production of this highly impermeable shield, which is the target for numerous anti-tuberculosis agents. The galactan domain of AG is synthesised via a bifunctional galactofuranosyltransferase (GlfT), which utilises UDP-Galf as its high-energy substrate. However, it has proven difficult to study the protein in its recombinant form due to difficulties in recovering pure soluble protein using standard expression systems. Herein, we describe the effects of glfT co-induction with a range of chaperone proteins, which resulted in an appreciable yield of soluble protein at 5 mg/L after a one-step purification procedure. We have shown that this purified enzyme transfers [14C]Galf to a range of both β(1 → 5) and β(1 → 6) linked digalactofuranosyl neoglycolipid acceptors with a distinct preference for the latter. Ligand binding studies using intrinsic tryptophan fluorescence have provided supporting evidence for the apparent preference of this enzyme to bind the β(1 → 6) disaccharide acceptor. However, we could not detect binding or galactofuranosyltransferase activity with an n-octyl β-d-Gal-(1 → 4)-α-l-Rha acceptor, which mimics the reducing terminus of galactan in the mycobacterial cell wall. Conversely, after an extensive bioinformatics analysis of the H37Rv genome, further cloning, expression and functional analysis of the Rv3792 open reading frame indicates that this protein affords galactofuranosyltransferase activity against such an acceptor and paves the way for a better understanding of galactan biosynthesis in Mycobacterium tuberculosis. 相似文献
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Orthoptera were monitored on field edge public footpaths on the east (leeward) and west (windward) side of hedgerows in Chelmsford,
UK, in 2006. A total of 6 species were recorded from footpaths on the leeward side of hedgerows probably due to the shelter
from the prevailing westerly winds provided by the trees and shrubs. On the windward side of hedgerows species richness and
abundance of Orthoptera were reduced (only 4 species were recorded). It is suggested that shelter from the wind and the exposure
to early morning sunlight for Orthoptera on the east side of hedgerows are important factors governing their occurrence on
farmland. Many replicates had Environmental Stewardship (ES) scheme field margins adjacent but they did not affect Orthoptera
species richness or abundance. 相似文献
38.
Background
OMA is a project that aims to identify orthologs within publicly available, complete genomes. With 657 genomes analyzed to date, OMA is one of the largest projects of its kind. 相似文献39.
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