Gα13 regulates methacholine-induced contraction of bronchial smooth muscle via phosphorylation of MLC20

Reversible airway constriction is induced by an increase in airway smooth muscle contractility in response to methacholine likely as a bronchospastic stimulus. Despite the finding of Gα₁₂ and Gα₁₃ up-regulation in airway hyperresponsive animals, their functional role of contraction in airway smooth muscle has not been directly explored. This study investigated the differential regulatory role of Gα₁₂/Gα₁₃ in methacholine-induced contraction of trachea and bronchus in Gα₁₂ or Gα₁₃ gene knockout mice after ovalbumin sensitization and challenges. Organ bath assays and videomicroscopy revealed that Gα₁₃ deficiency delayed methacholine-induced contractile response of bronchiolar smooth muscle, but not that of tracheal smooth muscle. In primary bronchial smooth muscle cells, knockdown of Gα₁₃ blocked methacholine-induced phosphorylation of 20 kDa regulatory light chain of myosin II (MLC₂₀), a prerequisite step for the contractile initiation of actin and myosin. Gα₁₃-dependent MLC₂₀ phosphorylation was confirmed in murine embryonic fibroblasts. After ovalbumin sensitization and challenges, wild type mice exhibited methacholine-induced bronchial contraction of lung tissue. Heterozygous absence of the Gα₁₃ gene abrogated methacholine-induced contractions, whereas homozygous absence of the Gα₁₂ gene failed to do so. Our findings indicate that Gα₁₃, but not Gα₁₂, specifically regulates cholinergic bronchial contraction in airway responsiveness via controlling phosphorylation of MLC₂₀ by methacholine.     

我国菰米对高脂膳食大鼠血脂及炎性因子的影响

目的探讨菰米对高脂膳食诱导脂代谢紊乱大鼠血脂及炎性因子水平的调控作用。方法44只雄性SD大鼠随机分为阴性对照组、高脂模型组、米面组和菰米组;以相应饲料连续喂养8w,测定各组大鼠体重、血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)、高敏C反应蛋白(hs-CRP)等指标。结果与阴性对照组相比,高脂模型组和米面组大鼠的血清TC、TG显著上升,HDL-C显著降低;与高脂模型组和米面组比较,菰米组的血清TC、TG显著下降,HDL-C显著升高,TNF-α、hs-CRP显著下降。结论菰米具有降低脂代谢紊乱大鼠血脂的作用,并能改善高脂血症的低度炎性状态。     

野生及栽培蔓荆子生药材中重金属元素分析

采用原子吸收分光光度法分别测定野生及栽培蔓荆子生药材中铅、砷、汞、镉、铜。结果蔓荆子野生品各一批次砷、汞含量超标,蔓荆子栽培品中重金属平均含量铅0.15μg/g、砷0.05μg/g、汞<0.01μg/g、镉0.18μg/g、铜3.95μg/g,符合绿色中药材重金属元素限量要求。     

Highly Pathogenic Avian Influenza Virus A (H7N3) in Domestic Poultry, Saskatchewan, Canada, 2007

Epidemiologic, serologic, and molecular phylogenetic methods were used to investigate an outbreak of highly pathogenic avian influenza on a broiler breeding farm in Saskatchewan, Canada. Results, coupled with data from influenza A virus surveillance of migratory waterfowl in Canada, implicated wild birds as the most probable source of the low pathogenicity precursor virus.     

First Case of Highly Pathogenic Avian Influenza in Poultry in Spain

In October 2009, highly pathogenic avian influenza virus (HPAIV) was isolated for the first time in poultry in Spain. Sequencing analysis revealed that it was an H7N7 HPAIV. The progenitors of H7 HPAIV strains involved in recent European poultry outbreaks were simultaneously circulating in wild birds. The infected Spanish farm is located close to a reservoir abundant in wild birds. Epidemiological investigation found no links to other poultry holdings and those located in the control area were negative for AIV. Previous spatial risk analyses had identified the area where the infected holding is located to beat high relative risk for the introduction and presence of H5N1 HPAIV by wild birds. We suggest a risk‐based surveillance scheme that targets smaller geographical units but maintains the number of wild birds being sampled, as early detection of potentially pathogenic AIV is crucial in preventing spread to poultry.     

Molecular Study of Free‐ranging Mule Deer and White‐tailed Deer from British Columbia,Canada, for Evidence of Anaplasma spp. and Ehrlichia spp.

Twenty‐three free‐ranging white‐tailed deer (WTD; Odocoileus virginianus) and six mule deer (MD; Odocoileus hemionus) from south‐central British Columbia, Canada, were tested for Anaplasma marginale by msp5 gene‐specific PCR and Ehrlichia spp. by 16S rRNA or citrate synthase (gltA) gene‐specific PCR, as well as by PCR with universal 16S rRNA primers detecting a wide range of bacteria. No deer tested positive for A. marginale. Amplification with universal 16S rRNA primers followed by sequencing of cloned fragments detected an Anaplasma sp. in one of 23 (4.3%) WTD and six of six (100%) MD and Bartonella sp. in four of 23 (17.4%) WTD. The Anaplasma sp. was genetically distinct from A. marginale and all other recognized members of the genus. Four of six (66.7%) MD and 0 of 23 (0%) WTD were Ehrlichia positive by PCR with primers for 16S rRNA and gltA genes. The sequences of gltA PCR fragments were identical to each other and to the respective region of the gltA gene of an Ehrlichia sp. which we detected previously in naturally infected cattle from the same area, suggesting the possibility of biological transmission of this rickettsia between cattle and wild cervids. Antibodies reactive with the MSP5 protein of A. marginale were detected using a competitive enzyme‐linked immunosorbent assay in two of six (33.3%) MD, but not in WTD. The two seropositive MD were PCR positive for both the Anaplasma sp. and Ehrlichia sp. detected in this study, suggesting a reaction of antibodies against one or both of these rickettsias with the MSP5 antigen.