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排序方式: 共有395条查询结果,搜索用时 46 毫秒
111.
He S Ye Z Dobbelaar PH Bakshi RK Hong Q Dellureficio JP Sebhat IK Guo L Liu J Jian T Lai Y Franklin CL Reibarkh M Holmes MA Weinberg DH MacNeil T Tang R Tamvakopoulos C Peng Q Miller RR Stearns RA Chen HY Chen AS Strack AM Fong TM Wyvratt MJ Nargund RP 《Bioorganic & medicinal chemistry letters》2010,20(22):6524-6532
We report an SAR study of MC4R analogs containing spiroindane heterocyclic privileged structures. Compound 26 with N-Me-1,2,4-triazole moiety possesses exceptional potency at MC4R and potent anti-obesity efficacy in a mouse model. However, the efficacy is not completely mediated through MC4R. Additional SAR studies led to the discovery of compound 32, which is more potent at MC4R. Compound 32 demonstrates MC4R mediated anti-obesity efficacy in rodent models. 相似文献
112.
Calum MacNeil Mark Briffa Rob S. E. W. Leuven Fiona R. Gell Richard Selman 《Hydrobiologia》2010,638(1):151-159
Freshwater invasive or alien species (IAS) can have a major impact on benthic macroinvertebrate assemblage structure and diversity.
This has implications for accurate biological monitoring, the assessment of the ecological quality status of rivers and achievement
of Water Framework Directive (WFD) objectives. Although IAS constitutes a major biological pressure to WFD objectives, current
approaches to ecological status assessment tend to ignore their presence. This problem is compounded as biotic indices such
as the Biological Monitoring Working Party (BMWP) score do not distinguish between native and IAS, when IAS tend to be more
tolerant of organic pollution than the natives they replace. Biocontamination is the presence of an IAS in a system, and we
tested a new method of biocontamination assessment, designed to be used alongside current routine water quality monitoring
techniques, by applying it to biological monitoring data from the river monitoring programme of a small Island, The Isle of
Man. Although 54% of monitoring sites exhibited no biocontamination, 19% showed low or moderate biocontamination and 27% high
or severe biocontamination. Richness contamination was low (only two contaminated families being recorded), but abundance
contamination was high in some sites (87% of individuals being IAS). Sites with a greater relative abundance of IAS individuals
exhibited lower BMWP water quality. Within invaded sites BMWP monitoring was not responsive to changing chemical water quality,
whereas within uninvaded sites it was. In invaded sites, the relative abundance of IAS increased as ammonia and BOD5 increased. Our study shows current monitoring approaches mask the presence of AIS within assemblages, with some highly biocontaminated
sites registering high BMWP biological quality. This new index represents a simple way to integrate the IAS biological pressure
into established WFD monitoring programmes, to produce more comprehensive estimates of ecological quality status than are
currently being realised. 相似文献
113.
Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), a longhorned beetle species native to Asia, has been introduced into several North American and European cities. Currently eradication and preventive measures are limited to identifying and destroying infested trees and protecting uninfested trees with trunk or soil-injections of the systemic insecticide imidacloprid. Because entomopathogenic fungi like Metarhizium brunneum Petch have been identified as virulent against these beetles we conducted several tests to determine the compatibility of the two agents in combination. Radial hyphal growth and the sporulation capacity of M. brunneum on Sabouraud dextrose agar with yeast were not significantly affected by the presence of imidacloprid. In a 2 × 3 factorial experiment investigating interactions between exposure to imidacloprid and M. brunneum we observed no effect of imidacloprid alone on beetle survival when beetles were given a single dose of 10 or 100 ppm compared to control insects. We observed a significant effect of exposure to M. brunneum, and a significant interaction between imidacloprid and M. brunneum representing a synergistic effect of dual treatment. Beetles exposed to the fungus alone lived significantly longer compared to insects treated with a single dose of 100 ppm imidacloprid (9.5 vs. 6.5 d). Consumption of striped maple twigs by beetles exposed to imidacloprid, across concentrations, was reduced 48% compared to control insects, where as consumption by M. brunneum-exposed beetles was reduced by 16% over the first 6-days of the test period. Beetles fed 100 ppm imidacloprid consumed 32% less over the first 3 d compared to beetles not exposed to imidacloprid and thereafter consumed as much as beetles not fed 100 ppm imidacloprid. M. brunneum-exposed beetles consumed significantly less food than control insects throughout the test period, and beetles treated with imidacloprid produced significantly fewer conidia compared to beetles not treated with imidacloprid. 相似文献
114.
William W. Lockwood Raj Chari Bradley P. Coe Kelsie L. Thu Cathie Garnis Chad A. Malloff Jennifer Campbell Ariane C. Williams Dorothy Hwang Chang-Qi Zhu Timon P. H. Buys John Yee John C. English Calum MacAulay Ming-Sound Tsao Adi F. Gazdar John D. Minna Stephen Lam Wan L. Lam 《PLoS medicine》2010,7(7)
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117.
MacNeil C Fielding NJ Hume KD Dick JT Elwood RW Hatcher MJ Dunn AM 《International journal for parasitology》2003,33(1):57-64
In a river survey, Gammarus pulex amphipods both unparasitised and parasitised with the acanthocephalan Echinorhynchus truttae were distributed similarly with respect to flow regimen, tending to be more abundant in faster, shallower, riffle patches. However, there was a higher prevalence of parasitism in faster, shallower areas than in slower, deeper areas and abundance correlated with macrophyte coverage for unparasitised but not parasitised amphipods, indicating subtle differences in habitat usage. A laboratory 'patch' simulation indicated that parasitism influenced micro-distribution. There were higher proportions of unparasitised amphipods in/under stone substrates and within weed. In contrast, there were higher proportions of parasitised amphipods in the water column and at the water surface. As the experiment progressed, unparasitised but not parasitised amphipod habitat usage shifted from those micro-habitats above the substrate and in the water column to those in/under the substrates. Experiments also demonstrated that parasitised amphipods were more active and had a greater preference for illumination. Previous studies of the effects of acanthocephalan parasitism of amphipod hosts have focussed on how drift behaviour is altered, now we show that subtle differences in micro-habitat usage could translate to greatly increased vulnerability to fish predation. We discuss how aggregation of parasitised individuals within specific habitats could promote parasite transmission. 相似文献
118.
MacNeil C Dick JT Hatcher MJ Fielding NJ Hume KD Dunn AM 《International journal for parasitology》2003,33(8):795-798
In its freshwater amphipod host Gammarus duebeni celticus, the microsporidian parasite Pleistophora mulleri showed 23% transmission efficiency when uninfected individuals were fed infected tissue, but 0% transmission by water-borne and coprophagous routes. Cannibalism between unparasitised and parasitised individuals was significantly in favour of the former (37% compared to 0%). In addition, cannibalism between parasitised individuals was significantly higher than between unparasitised individuals (27% compared to 0%). Thus, parasitised individuals were more likely to be cannibalised by both unparasitised and parasitised individuals. We discuss the conflicting selective forces within this host/parasite relationship, the implications of parasite mediated cannibalism for host population structure and the impacts this may have on the wider aquatic community. 相似文献
119.
Phospholipase C is required for the control of stomatal aperture by ABA 总被引:20,自引:0,他引:20
Hunt L Mills LN Pical C Leckie CP Aitken FL Kopka J Mueller-Roeber B McAinsh MR Hetherington AM Gray JE 《The Plant journal : for cell and molecular biology》2003,34(1):47-55
The calcium-releasing second messenger inositol 1,4,5-trisphosphate is involved in the regulation of stomatal aperture by ABA. In other signalling pathways, inositol 1,4,5-trisphosphate is generated by the action of phospholipase C. We have studied the importance of phospholipase C in guard cell ABA-signalling pathways. Immunolocalisation of a calcium-activated phospholipase C confirmed the presence of phospholipase C in tobacco guard cells. Transgenic tobacco plants with considerably reduced levels of phospholipase C in their guard cells were only partially able to regulate their stomatal apertures in response to ABA. These results suggest that phospholipase C is involved in the amplification of the calcium signal responsible for reductions in stomatal aperture in response to ABA. As full ABA-induced inhibition of stomatal opening was not observed, our results support a role for the action of other calcium-releasing second messengers in the guard cell ABA-signalling pathway. It is not known whether these different calcium-releasing second messengers act in the same or parallel ABA-signalling pathways. 相似文献
120.
Martinez A Kolvek SJ Yip CL Hopke J Brown KA MacNeil IA Osburne MS 《Applied and environmental microbiology》2004,70(4):2452-2463
The enormous diversity of uncultured microorganisms in soil and other environments provides a potentially rich source of novel natural products, which is critically important for drug discovery efforts. Our investigators reported previously on the creation and screening of an Escherichia coli library containing soil DNA cloned and expressed in a bacterial artificial chromosome (BAC) vector. In that initial study, our group identified novel enzyme activities and a family of antibacterial small molecules encoded by soil DNA cloned and expressed in E. coli. To continue our pilot study of the utility and feasibility of this approach to natural product drug discovery, we have expanded our technology to include Streptomyces lividans and Pseudomonas putida as additional hosts with different expression capabilities, and herein we describe the tools we developed for transferring environmental libraries into all three expression hosts and screening for novel activities. These tools include derivatives of S. lividans that contain complete and unmarked deletions of the act and red endogenous pigment gene clusters, a derivative of P. putida that can accept environmental DNA vectors and integrate the heterologous DNA into the chromosome, and new BAC shuttle vectors for transferring large fragments of environmental DNA from E. coli to both S. lividans and P. putida by high-throughput conjugation. Finally, we used these tools to confirm that the three hosts have different expression capabilities for some known gene clusters. 相似文献