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131.
Yi Ting Zhou Li Li Chew Sheng-cai Lin Boon Chuan Low 《Molecular biology of the cell》2010,21(18):3232-3246
The BNIP-2 and Cdc42GAP homology (BCH) domain is a novel regulator for Rho GTPases, but its impact on p50-Rho GTPase-activating protein (p50RhoGAP or Cdc42GAP) in cells remains elusive. Here we show that deletion of the BCH domain from p50RhoGAP enhanced its GAP activity and caused drastic cell rounding. Introducing constitutively active RhoA or inactivating GAP domain blocked such effect, whereas replacing the BCH domain with endosome-targeting SNX3 excluded requirement of endosomal localization in regulating the GAP activity. Substitution with homologous BCH domain from Schizosaccharomyces pombe, which does not bind mammalian RhoA, also led to complete loss of suppression. Interestingly, the p50RhoGAP BCH domain only targeted RhoA, but not Cdc42 or Rac1, and it was unable to distinguish between GDP and the GTP-bound form of RhoA. Further mutagenesis revealed a RhoA-binding motif (residues 85-120), which when deleted, significantly reduced BCH inhibition on GAP-mediated cell rounding, whereas its full suppression also required an intramolecular interaction motif (residues 169-197). Therefore, BCH domain serves as a local modulator in cis to sequester RhoA from inactivation by the adjacent GAP domain, adding to a new paradigm for regulating p50RhoGAP signaling. 相似文献
132.
Gillian D Alton David L Pearl Ken G Bateman W Bruce McNab Olaf Berke 《BMC veterinary research》2010,6(1):42
Background
Ontario provincial abattoirs have the potential to be important sources of syndromic surveillance data for emerging diseases of concern to animal health, public health and food safety. The objectives of this study were to: (1) describe provincially inspected abattoirs processing cattle in Ontario in terms of the number of abattoirs, the number of weeks abattoirs process cattle, geographical distribution, types of whole carcass condemnations reported, and the distance animals are shipped for slaughter; and (2) identify various seasonal, secular, disease and non-disease factors that might bias the results of quantitative methods, such as cluster detection methods, used for food animal syndromic surveillance. 相似文献133.
Knowledge on transport and deposition of fine particulate organic matter (FPOM) from reservoir dams is increasingly required
for habitat management and restoration of dam tailwater ecosystems. Variations in the transport distance of FPOM, however,
have never been studied well, particularly in relation to channel morphology, due to channel size restrictions of artificial
tracers such as corn pollen when applied to larger river channels. This study aims to show the relations between FPOM retention
efficiency and channel morphology in dam tailwaters using lentic plankters as tracers. We estimated the mean transport distance,
S
p, by calculating downstream reduction ratios of lentic tracer plankters and calculated the deposition velocity, v
dep. Suspended FPOM samples were collected in tailwaters of two river channels below reservoir dams and two artificial canals
below Lake Biwa in the Yodo River system. The longest S
p (19.2 km) and the shortest one (2.2 km) were recorded in the deep canal and shallow canal, respectively, showing a positive
correlation with channel hydraulic radius. The values of v
dep were 4.7–6.4 times higher in river channels than in artificial canals. These results indicate that increasing complexity
of bed morphology can minimize S
p, whereas bed degradation and armored bed materials may lead to increased S
p. Advantages of lentic plankters as tracers for estimating distance ranges of reservoir dam impact on river ecosystems are
also discussed. 相似文献
134.
H Härtel S Nikunen E Neuvonen R Tanskanen S-L Kivelä P Aho T Soveri H Saloniemi 《Acta veterinaria Scandinavica》2004,45(4):193-200
Pathogens causing bovine respiratory tract disease in Finland were investigated. Eighteen cattle herds with bovine respiratory
disease were included. Five diseased calves from each farm were chosen for closer examination and tracheobronchial lavage.
Blood samples were taken from the calves at the time of the investigation and from 86 calves 3–4 weeks later. In addition,
6–10 blood samples from animals of different ages were collected from each herd, resulting in 169 samples. Serum samples were
tested for antibodies to bovine parainfluenza virus-3 (PIV-3), bovine respiratory syncytial virus (BRSV), bovine coronavirus
(BCV), bovine adenovirus-3 (BAV-3) and bovine adenovirus-7 (BAV-7). About one third of the samples were also tested for antibodies
to bovine virus diarrhoea virus (BVDV) with negative results. Bacteria were cultured from lavage fluid and in vitro susceptibility
to selected antimicrobials was tested. According to serological findings, PIV-3, BAV-7, BAV-3, BCV and BRSV are common pathogens
in Finnish cattle with respiratory problems. A titre rise especially for BAV-7 and BAV-3, the dual growth of Mycoplasma dispar and Pasteurella multocida, were typical findings in diseased calves. Pasteurella sp. strains showed no resistance to tested antimicrobials. Mycoplasma bovis and Mannheimia haemolytica were not found. 相似文献
135.
J Blake D M Helmeste C H Li 《International journal of peptide and protein research》1985,25(6):575-579
Two analogs of human beta-endorphin (beta-EP) which contain cystine bridges, [Cys15-Cys26,Phe27,Gly31]-beta-EP (I) and [Cys16-Cys26,Phe27,Gly31]-beta-EP (II), were synthesized by the solid-phase method. Peptides I and II were shown to contain 2-2.5 times the opiate receptor binding activity of beta-endorphin. We also synthesized two analogs with reduced alkylated cysteine residues and these peptides, [Arg9,19,24,28,29 Cys(Cam)11,26,Phe27,Gly31] and [Arg9,19,24,28,29,Cys-(Cam)12,26,Phe27,Gly31], were shown to have approximately the same opiate receptor activity as beta-endorphin. 相似文献
136.
Wenjun Geng Jinggong Xiangyu Xiuzhen Li Zhongning Zhang Deyuan Han Yongwei Li 《Insect Science》1997,4(4):364-368
Abstract Field trials by sex pheromone of aphid to trap peach aphids Myzus persicae have been carried out in 1995 and in 1996. Suitable time and the effect of ratio of two components nepetalactone and nepetalactol to apply the lure have been observed. 相似文献
137.
Background
Chow and Liu showed that the maximum likelihood tree for multivariate discrete distributions may be found using a maximum weight spanning tree algorithm, for example Kruskal's algorithm. The efficiency of the algorithm makes it tractable for high-dimensional problems. 相似文献138.
139.
The effects of invasive macrophytes, water level fluctuations and predation on freshwater unionids Pyganodon grandis and Utterbackia imbecillis were studied in three small impoundments in Northeastern Texas in 2003–2005. Mussel density was sampled with quadrats. Mortality,
associated with the water level fluctuations and predation, was estimated by collecting dead shells on the shore at about
two month intervals. In two ponds, horizontal distribution of unionids was limited by dense beds of invasive and noxious macrophytes
(mainly Eurasian watermilfoil Myriophyllum spicatum and American lotus Nelumbo lutea): mussel densities were significantly lower in these macrophyte beds (P < 0.001). In the third pond with the lowest density of macrophytes (stonewort Chara sp.), unionids were distributed more evenly, and the average unionid biomass was the highest among all ponds studied. Vertical
distribution of unionids in all ponds was likely limited by low oxygen at depth >2 m. The total amount of shells found on
the shore per year varied from 0.1% to 28% of the total population in the pond and was negatively correlated with water level
(r = −0.72 to −0.81, P < 0.005). Mammalian predators consumed up to 19% of the total unionid population and predation was facilitated by water level
fluctuations.
Handling editor: K. Martens 相似文献
140.