横断山北部高山区不同生态条件下土壤微生物数量及其与生态因子的相关性

采用全球定位系统(GPS)采集了横断山北部高山区35个样点的土样,用稀释平板法对该区细菌、真菌和放线菌进行分离计数,并分析了微生物数量与土壤养分、土壤水分、土地利用方式和pH等因子的相关性。结果表明,该区域3大类土壤微生物数量表现为细菌>放线菌>真菌。土壤微生物数量在不同区域表现为松林口>雀儿山>折多山;林地微生物比草地丰富,但不及草地微生物均衡。微生物数量与土壤理化因子间的相关分析表明,放线菌数量与pH呈显著正相关,真菌数量与土壤全钾含量呈极显著正相关。     

戈谢氏病致病机制及治疗方法

戈谢氏病(Gaucher's disease,GD)又称葡萄糖脑苷脂沉积病,是溶酶体贮积症(Lysosomal storage disorder)中最常见的一种,为常染色体隐性遗传病。此病因溶酶体中β-葡糖脑苷脂酶(β-glucocerebrosidase, GBA)编码基因异常,致使该酶活性降低,葡糖脑苷脂(Glucocerebroside, GlcCer)不能被水解而聚积在脑组织、肝脏、脾等组织的溶酶体及单核–巨噬系统中,导致细胞失去原有的功能而产生一系列症状：脑损伤、肝脾肿大、骨损害、血细胞减少、生长发育迟滞等。Ⅰ型GD以酶替代治疗(Enzyme replacement therapy, ERT)为主,但Ⅱ型和Ⅲ型无有效的治疗方法。文章对GD的致病机制及治疗方法的最新进展进行了综述。     

腓骨肌萎缩症4型遗传学研究进展

腓骨肌萎缩症也称夏科-马利-杜斯氏病(Charcot-Marie-Tooth disease, CMT),是人类最常见的遗传性周围神经病之一,其遗传方式以常染色体显性遗传为主,也有部分呈常染色体隐性遗传或X连锁显性或隐性遗传。根据临床表型将CMT分为脱髓鞘型(CMT1)、轴突型(CMT2)和中间型（DI-CMT）。常染色体隐性遗传的CMT1(AR-CMT1,也称CMT4型)临床表现除了CMT常见的四肢远端进行性肌无力和萎缩,以及高足弓和爪形手外,常起病早,进展迅速,并有不同程度的感觉障碍和脊柱畸形(以脊柱侧凸为主)。近年来的研究显示,CMT4有11种亚型,其中有些亚型的致病机制较明确,有些亚型存在建立者突变,有些亚型还局限在临床描述和突变检出上。文章综述了CMT4的最新研究进展,包括各亚型的临床表现、致病机制和小鼠模型等。     

禽流感病毒感染人类及其致病机制研究

禽流感病毒感染禽类可引发呼吸系统到全身不同程度的病变,严重的可导致败血症、休克、多脏器功能衰竭,甚至死亡。上世纪末,禽流感病毒开始跨种向人类传播,其感染引起急性肺损伤、多器官衰竭等,具有较高的致病率和致死率,危害极大,引起了研究者的广泛关注。目前禽流感病毒感染人类及其致病机制尚不明确,本文就此做一综述,为其防治提供参考。     

有益微生物缓解花生连作障碍机理研究进展

花生是我国重要的油料作物,种植过程中会遇到连作障碍问题.有益微生物可以有效缓解花生连作障碍,其机理包括有益微生物分解化感物质、改变花生根际微生物区系、增加花生抗病能力、促进花生结瘤固氮、促进花生养分吸收五个方面.阐明该机理,对花生连作障碍缓解有指导意义,对其他作物连作障碍的缓解也有参考价值.     

Effect of low-concentration chlorine dioxide gas against bacteria and viruses on a glass surface in wet environments

Aims: To evaluate the efficacy of low‐concentration chlorine dioxide (ClO₂) gas against model microbes in the wet state on a glass surface. Methods and Results: We set up a test room (39 m³) and the ClO₂ gas was produced by a ClO₂ gas generator that continuously releases a constant low‐concentration ClO₂ gas. Influenza A virus (Flu‐A), feline calicivirus (FCV), Staphylococcus aureus and Escherichia coli were chosen as the model microbes. The low‐concentration ClO₂ gas (mean 0·05 ppmv, 0·14 mg m^?3) inactivated Flu‐A and E. coli (>5 log₁₀ reductions) and FCV and S. aureus (>2 log₁₀ reductions) in the wet state on glass dishes within 5 h. Conclusions: The treatment of wet environments in the presence of human activity such as kitchens and bathrooms with the low‐concentration ClO₂ gas would be useful for reducing the risk of infection by bacteria and viruses residing on the environmental hard surfaces without adverse effects. Significance and Impact of the Study: This study demonstrates that the low‐concentration ClO₂ gas (mean 0·05 ppmv) inactivates various kinds of microbes such as Gram‐positive and Gram‐negative bacteria, enveloped and nonenveloped viruses in the wet state.     

Highly pathogenic avian influenza outbreak mitigated by seasonal low pathogenic strains: Insights from dynamic modeling

The spread of highly pathogenic avian influenza (HPAI) H5N1 remains a threat for both wild and domestic bird populations, while low pathogenic avian influenza (LPAI) strains have been reported to induce partial immunity to HPAI in poultry and some wild birds inoculated with both HPAI and LPAI strains. Here, based on the reported data and experiments, we develop a two-strain avian influenza model to examine the extent to which this partial immunity observed at the individual level can affect the outcome of the outbreaks among migratory birds in the wild at the population level during different seasons. We find a distinct mitigating effect of LPAI on the death toll induced by HPAI strain, and this effect is particularly important for populations previously exposed to and recovered from LPAI. We further investigate the effect of the dominant mode of transmission of an HPAI strain on the outcome of the epidemic. Four combinations of contact based direct transmission and indirect fecal-to-oral (or environmental) routes are examined. For a given infection peak of HPAI, indirect fecal-to-oral transmission of HPAI can lead to a higher death toll than that associated with direct transmission. The mitigating effect of LPAI can, in turn, be dependent on the route of infection of HPAI.