地下水埋深和季节性干旱对古尔班通古特沙漠南缘梭梭生理和生长的影响

干旱区因降水稀少,地下水成为荒漠植被重要且稳定的水源。选取古尔班通古特沙漠南缘建群种植物梭梭（Haloxylon ammodendron）为研究对象,通过测量不同地下水埋深（3.45、9.08、10.47、13.27 m和15.91 m）下生长季前期和后期同化枝生理生化指标（黎明水势、正午水势、含水量、氯离子、钠离子、脯氨酸和非结构性碳水化合物）和生长与形态特征（生长速率和胡伯尔值）,旨在认识荒漠植物对地下水埋深增加和季节性干旱的响应特征和调节适应机制。结果表明：（1）梭梭应对地下水埋深变化的生理调节对策,是采取先降低后升高黎明前同化枝水势、降低新枝形成期同化枝生长速率、增大胡伯尔值和积累非结构性碳水化合物的策略;（2）梭梭应对生长季大气干旱的生理调节对策,是通过降低黎明前同化枝水势、维持较高胡伯尔值、积累钠离子和消耗淀粉抵御季节性干旱;（3）在大气干旱与地下水水文干旱交互作用下,梭梭是采取降低正午同化枝水势、维持较高的同化枝含水量和积累可溶性糖的生态策略。综上所述,梭梭在响应地下水水文干旱和季节性大气干旱的生理特征间存在差异。研究结果丰富了水文和大气干旱对梭梭生理和生长影响的认知,可以为基于地下水资源管理的干旱区荒漠植被保育提供参考。     

Borna disease virus P protein affects neural transmission through interactions with gamma-aminobutyric acid receptor-associated protein

Borna disease virus (BDV) is one of the infectious agents that causes diseases of the central nervous system in a wide range of vertebrate species and, perhaps, in humans. The phosphoprotein (P) of BDV, an essential cofactor of virus RNA-dependent RNA polymerase, is required for virus replication. In this study, we identified the gamma-aminobutyric acid receptor-associated protein (GABARAP) with functions in neurobiology as one of the viral P protein-interacting cellular factors by using an approach of phage display-based protein-protein interaction analysis. Direct binding between GABARAP and P protein was confirmed by coimmunoprecipitation, protein pull-down, and mammalian two-hybrid analyses. GABARAP originally was identified as a linker between the gamma-aminobutyric acid receptor (GABAR) and the microtubule to regulate receptor trafficking and plays important roles in the regulation of the inhibitory neural transmitter gamma-aminobutyric acid (GABA). We showed that GABARAP colocalizes with P protein in the cells infected with BDV or transfected with the P gene, which resulted in shifting the localization of GABARAP from the cytosol to the nucleus. We further demonstrated that P protein blocks the trafficking of GABAR, a principal GABA-gated ion channel that plays important roles in neural transmission, to the surface of cells infected with BDV or transfected with the P gene. We proposed that during BDV infection, P protein binds to GABARAP, shifts the distribution of GABARAP from the cytoplasm to the nucleus, and disrupts the trafficking of GABARs to the cell membranes, which may result in the inhibition of GABA-induced currents and in the enhancement of hyperactivity and anxiety.     

Activation of interleukin-32 pro-inflammatory pathway in response to influenza A virus infection

Background

Interleukin (IL)-32 is a recently described pro-inflammatory cytokine that has been reported to be induced by bacteria treatment in culture cells. Little is known about IL-32 production by exogenous pathogens infection in human individuals.

Methods and Findings

In this study, we found that IL-32 level was increased by 58.2% in the serum samples from a cohort of 108 patients infected by influenza A virus comparing to that of 115 healthy individuals. Another pro-inflammatory factor cyclooxygenase (COX)-2-associated prostaglandin E2 was also upregulated by 2.7-fold. Expression of IL-32 in influenza A virus infected A549 human lung epithelial cells was blocked by either selective COX-2 inhibitor NS398 or Aspirin, a known anti-inflammatory drug, indicating IL-32 was induced through COX-2 in the inflammatory cascade. Interestingly, we found that COX-2-associate PGE₂ production activated by influenza virus infection was significantly suppressed by over-expression of IL-32 but increased by IL-32-specific siRNA, suggesting there was a feedback mechanism between IL-32 and COX-2.

Conclusions

IL-32 is induced by influenza A virus infection via COX-2 in the inflammatory cascade. Our results provide that IL-32 is a potential target for anti-inflammatory medicine screening.     

Soil microbial community shifts explain habitat heterogeneity in two Haloxylon species from a nutrient perspective

Haloxylon ammodendron and Haloxylon persicum (as sister taxa) are dominant shrubs in the Gurbantunggut Desert. The former grows in inter-dune lowlands while the latter in sand dunes. However, little information is available regarding the possible role of soil microorganisms in the habitat heterogeneity in the two Haloxylon species from a nutrient perspective. Rhizosphere is the interface of plant–microbe–soil interactions and fertile islands usually occur around the roots of desert shrubs. Given this, we applied quantitative real-time PCR combined with MiSeq amplicon sequencing to compare their rhizosphere effects on microbial abundance and community structures at three soil depths (0–20, 20–40, and 40–60 cm). The rhizosphere effects on microbial activity (respiration) and soil properties had also been estimated. The rhizospheres of both shrubs exerted significant positive effects on microbial activity and abundance (e.g., eukarya, bacteria, and nitrogen-fixing microbes). The rhizosphere effect of H. ammodendron on microbial activity and abundance of bacteria and nitrogen-fixing microbes was greater than that of H. persicum. However, the fertile island effect of H. ammodendron was weaker than that of H. persicum. Moreover, there existed distinct differences in microbial community structure between the two rhizosphere soils. Soil available nitrogen, especially nitrate nitrogen, was shown to be a driver of microbial community differentiation among rhizosphere and non-rhizosphere soils in the desert. In general, the rhizosphere of H. ammodendron recruited more copiotrophs (e.g., Firmicutes, Bacteroidetes, and Proteobacteria), nitrogen-fixing microbes and ammonia-oxidizing bacteria, and with stronger microbial activities. This helps it maintain a competitive advantage in relatively nutrient-rich lowlands. Haloxylon persicum relied more on fungi, actinomycetes, archaea (including ammonia-oxidizing archaea), and eukarya, with higher nutrient use efficiency, which help it adapt to the harsher dune crests. This study provides insights into the microbial mechanisms of habitat heterogeneity in two Haloxylon species in the poor desert soil.     

利用红外相机对湖南壶瓶山国家级自然保护区兽类和鸟类多样性的初步调查

2012年8月至2015年8月,在壶瓶山国家级自然保护区布设了20个红外相机监测公里网格,对保护区的兽类和鸟类多样性进行了初步调查。经过19,592个有效相机工作日的调查,共记录到兽类4目11科21种和鸟类4目8科33种,其中有国家Ⅰ级重点保护野生动物1种（林麝 Moschus berezovskii）、国家Ⅱ级重点保护野生动物8种和保护区新纪录兽类1种（红腿长吻松鼠Dremomys pyrrhomerus）。兽类以食肉目种类最多（9种）,其次为鲸偶蹄目（6种）和啮齿目（5种）。毛冠鹿（Elaphodus cephalophus）、野猪（Sus scrofa）、红腿长吻松鼠、小麂（Muntiacus reevesi）和猪獾（Arctonyx collaris）的相对丰富度居于兽类的前5位。鸟类以雀形目的种类最多（25种）,其次是鸡形目（5种）和鴷形目（2种）。红腹锦鸡（Chrysolophus pictus）、红腹角雉（Tragopan temminckii）和眼纹噪鹛（Garrulax ocellatus）的相对丰富度指数居于鸟类的前3位。此外,本文对红腹锦鸡、红腹角雉、红腿长吻松鼠、毛冠鹿、野猪和小麂等常见物种的日活动节律和年活动节律进行了初步分析。本次调查初步了解了保护区内地栖大中型兽类和鸟类的本底信息,为保护区今后开展野生动物长期监测提供了重要依据。     

鄱阳湖苦草及马来眼子菜PSⅡ荧光参数对水深变化的光响应

以典型沉水植物苦草和马来眼子菜为材料,利用水下饱和脉冲调制叶绿素荧光仪研究不同水深(0.5、1.0、1.5、2.0、2.5 m)对两种植物叶片最小荧光(Fo)、最大荧光(Fm)、PSⅡ最大光化光效率(Fv/Fm)、有效量子产量[Y(Ⅱ)]、光化学淬灭系数(qP)、非光化学淬灭系数(qN)、非调节性能量耗散的量子产量[Y(NO)]等荧光参数的影响。结果表明:水深1.5～2.0 m处苦草生物量最大,而1.0～1.5 m处马来眼子菜的最大;两种植物的Fo均先降低后升高,而荧光参数[(Fm、Fv/Fm、Fv/Fo、Y(Ⅱ)、qP]均先升高后降低; 2.0m处苦草的Fv/Fm、Fv/Fo最大,1.5 m处马来眼子菜的最大;相同水深下,马来眼子菜的qN比苦草低,与qP变化趋势相反;苦草的Y(Ⅱ)最大值出现在水深1.5～2.0 m内,马来眼子菜的Y(Ⅱ)最大值出现在1.5 m处;两者的Y(NO)随水深变化均表现出显著差异,过高或过低水深均抑制植物生长;相对光合电子传递速率(ETR)在不同水深处理间均差异显著,苦草的最大ETR比马来眼子菜小,说明其有较强的耐弱光能力。综上所述,在水深1.5～2.0 m苦草光合能力最强,最适宜生长;水深1.0～1.5 m最适宜马来眼子菜生长。     

A new silver nanochain SERS analytical platform to detect trace hexametaphosphate with a rhodamine S molecular probe

Using AgNO₃ as the precursor, stable silver nanochain (AgNC) sols, orange‐red in color, were prepared using hydrazine hydrate. A strong surface plasmon resonance Rayleigh scattering (RRS) peak occurred at 420 nm plus two surface plasmon resonance (SPR) absorption peaks at 410 nm and 510 nm. Rhodamine S (RhS) cationic dye was absorbed on the as‐prepared AgNC substrate to obtain a RhS–AgNC surface‐enhanced Raman scattering (SERS) nanoprobe that exhibited a strong SERS peak at 1506 cm^–1 and a strong RRS peak at 375 nm. Upon addition of the analyte sodium hexametaphosphate (HP), it reacted with RhS, which resulted in a decrease in the SERS and RRS peaks that was studied in detail. The decreased SERS and RRS intensities correlated linearly with HP concentration in the range of 0.0125–0.3 µmol/L and 0.05–1.0 µmol/L, with a detection limit of 6 nmol/L and 20 nmol/L HP respectively. Due to advantages of high sensitivity, good selectivity and simple operation, the RhS molecular probes were used to determine HP concentration in real samples. Copyright © 2015 John Wiley & Sons, Ltd.     

A simple and sensitive resonance Rayleigh scattering method for determination of As(III) using aptamer‐modified nanogold as a probe

A simple and selective aptamer (ssDNA)‐modified nanogold probe (AussDNA) was prepared for the determination of trace As(III) in HEPES buffer solution (pH 8.2) containing 0.05 mol/L NaCl. The method coupled the aptamer reaction of AussDNA–As(III) and the resonance Rayleigh scattering (RRS) of nanogold aggregations at 278 nm. When the As(III) concentration increased, the RRS intensity at 278 nm increased to form more nanogold aggregation and a stable As(III)–ssDNA complex. Under selected conditions, the increased RRS intensity (ΔI) was linear to the concentration of As(III) in the range 3.8–230.4 ng/mL, with a detection limit of 1.9 ng/mL. This RRS method was applied to detect As(III) in water samples, with simplicity, sensitivity and selectivity. Copyright © 2013 John Wiley & Sons, Ltd.