Identification of a Highly Conserved Epitope on Avian Influenza Virus Non-Structural Protein 1 Using a Peptide Microarray

Avian influenza virus (AIV) non-structural protein 1 (NS1) is a multifunctional protein. It is present at high levels in infected cells and can be used for AIV detection and diagnosis. In this study, we generated monoclonal antibody (MAb) D7 against AIV NS1 protein by immunization of BALB/c mice with purified recombinant NS1 protein expressed in Escherichia coli. Isotype determination revealed that the MAb was IgG₁/κ-type subclass. To identify the epitope of the MAb D7, the NS1 protein was truncated into a total of 225 15-mer peptides with 14 amino acid overlaps, which were spotted for a peptide microarray. The results revealed that the MAb D7 recognized the consensus DAPF motif. Furthermore, the AIV NS1 protein with the DAPF motif deletion was transiently expressed in 293T cells and failed to react with MAb D7. Subsequently, the DAPF motif was synthesized with an elongated GSGS linker at both the C- and N-termini. The MAb D7 reacted with the synthesized peptide both in enzyme-linked immunosorbent assay (ELISA) and dot-blot assays. From these results, we concluded that DAPF motif is the epitope of MAb D7. To our knowledge, this is the first report of a 4-mer epitope on the NS1 protein of AIV that can be recognized by MAb using a peptide microarray, which is able to simplify epitope identification, and that could serve as the basis for immune responses against avian influenza.     

Seed-to-seed potential allelopathic effects between <Emphasis Type="Italic">Ligularia virgaurea</Emphasis> and native grass species of Tibetan alpine grasslands

Allelopathy is an important process in plant communities, but the role of seed allelopathy in natural ecosystems remains poorly understood. In the present study, we examined the potential allelopathic effects of Ligularia virgaurea (a dominant species in degraded Tibetan grasslands) seeds on the germination of four native grass species (Festuca sinensis, Agrostis gigantean, Bromus inermis, and Elymus nutans). The results showed that L. virgaurea seeds can have potential allelopathic effects on seed germination, mean time to germination and root growth rates of native grass species. We further demonstrate that these effects are driven by a water-soluble seed leachate. Species with smaller seeds were generally more sensitive than larger seeded species. The results suggest that seed-to-seed allelopathic potential may be an important mechanism driving the dominance of L. virgaurea in degraded alpine grasslands on the Tibetan Plateau. Further studies are required to demonstrate effects of seed-to-seed potential allelopathy in a field setting.     

塔克拉玛干沙漠腹地胡杨林土壤细菌多样性分析

【目的】对塔克拉玛干沙漠腹地胡杨林土壤细菌多样性进行初步探索,为下一步从中筛选可用于生物饲料或生物肥料的微生物奠定基础。【方法】采用可培养方法,进行细菌的分离纯化。对各菌株进行革兰氏染色及淀粉酶、酯酶、纤维素酶和NaCl耐受浓度的测定,并提取各菌株基因组DNA,进行16SrRNA基因扩增、测序及系统进化树的绘制,分析其多样性。【结果】共分离得到27株菌,其中放线菌门(Actinobacteria)16株,变形菌门(Proteobacteria)4株,厚壁菌门(Firmicutes)6株,拟杆菌门(Bacteroidetes)1株。革兰氏染色结果表明,5株菌为革兰氏阴性,其余为革兰氏阳性;酶活测定结果表明,15株菌具有淀粉酶活性,9株菌具有酯酶活性,9株菌具有纤维素酶活性;NaCl耐受浓度测定结果显示,NaCl浓度为2%时所有菌株均能生长,5%时能生长的有22株,15%时能生长的有1株。【结论】塔克拉玛干沙漠腹地胡杨林土壤中存在较丰富的细菌类群,且具有一定的酶学活性和NaCl耐受性,具有进一步研究开发的价值。     

Cotton (Gossypium hirsutum) 14‐3‐3 proteins participate in regulation of fibre initiation and elongation by modulating brassinosteroid signalling

Cotton (Gossypium hirsutum) fibre is an important natural raw material for textile industry in the world. Understanding the molecular mechanism of fibre development is important for the development of future cotton varieties with superior fibre quality. In this study, overexpression of Gh14‐3‐3L in cotton promoted fibre elongation, leading to an increase in mature fibre length. In contrast, suppression of expression of Gh14‐3‐3L, Gh14‐3‐3e and Gh14‐3‐3h in cotton slowed down fibre initiation and elongation. As a result, the mature fibres of the Gh14‐3‐3 RNAi transgenic plants were significantly shorter than those of wild type. This ‘short fibre’ phenotype of the 14‐3‐3 RNAi cotton could be partially rescued by application of 2,4‐epibrassinolide (BL). Expression levels of the BR‐related and fibre‐related genes were altered in the Gh14‐3‐3 transgenic fibres. Furthermore, we identified Gh14‐3‐3 interacting proteins (including GhBZR1) in cotton. Site mutation assay revealed that Ser163 in GhBZR1 and Lys51/56/53 in Gh14‐3‐3L/e/h were required for Gh14‐3‐3‐GhBZR1 interaction. Nuclear localization of GhBZR1 protein was induced by BR, and phosphorylation of GhBZR1 by GhBIN2 kinase was helpful for its binding to Gh14‐3‐3 proteins. Additionally, 14‐3‐3‐regulated GhBZR1 protein may directly bind to GhXTH1 and GhEXP promoters to regulate gene expression for responding rapid fibre elongation. These results suggested that Gh14‐3‐3 proteins may be involved in regulating fibre initiation and elongation through their interacting with GhBZR1 to modulate BR signalling. Thus, our study provides the candidate intrinsic genes for improving fibre yield and quality by genetic manipulation.     

Governmental policies on HIV infection in China

EVOLUTION OF THE GOVERNMENT POLI- CIES Looking back 20 and more years, one could have hardly imagined that such great changes would have happened to the governmental policies on HIV/AIDS in China. In the earlier phase of the epidemic, laws and regulations were drafted based on the practices and experiences of preven- tion and control of other infectious diseases, such as isolation, quarantine and compulsory testing and examina- tions etc. When the HIV/AIDS epidemic was firstl…     

纳米银在水-沉积物中的迁移机制研究

为研究纳米银(Ag NPs)在水体中的迁移、水-沉积物中的分配及转化机制,采用武汉东湖湖水及沉积物开展模拟实验,以硝酸银(Ag NO3)为参照,研究了Ag NPs和聚乙烯吡咯烷酮包裹纳米银[Poly(vinylpyrrolidone)-coated silver nanoparticles(PVP-Ag NPs)]在上覆水中的沉降、在沉积物中的迁移和形态分布、以及扰动释放过程。结果表明,上覆水银初始浓度均为75 mg/L的Ag NO3、Ag NPs及PVP-Ag NPs在120h后分别为0.086、0.957和2.770 mg/L,显示纳米银和硝酸银进入水体后120h内大部分沉入沉积物中,且经过包裹的纳米银比未包裹的纳米银在水中停留时间稍长;60d后三种银均主要分布在表层沉积物中,Ag NO3体系银含量随深度的增加而逐渐降低,Ag NPs和PVP-Ag NPs体系银在2 cm以上随深度的增加而增高,随后逐渐降低,表明纳米银比硝酸银具有更强的迁移能力。此外,PVP-Ag NPs在2—3 cm层中的银含量占总量的24.6%,而Ag NPs在同一层中含量仅为2.6%,说明前者的迁移能力更强。在沉积物中,硫化物和有机物是银的主要结合相。释放实验结果表明,沉积物中纳米银的释放量远小于硝酸银的释放量,表明纳米银一旦与沉积物结合就难以再次释放。以上实验结果为评价纳米银的生态安全提供了科学依据。     

Enhanced production of a novel cytotoxic chromone oxalicumone A by marine-derived mutant Penicillium oxalicum SCSIO 24–2

Many marine natural products hold great potential for the development of new and much needed drugs. However, the production of active metabolites by marine-derived microorganisms is usually very low, and large-scale culture has to be involved to meet the need of chemical structural modification and deep pharmacy study. In order to enhance the production of a novel cytotoxic sulfur-containing chromone oxalicumone A (OA), germinating spores of a marine-derived wild strain Penicillium oxalicum SCSGAF 0023 were mutated by microwave and ultraviolet light irradiation, which led to the obtainment of a mutant P. oxalicum SCSIO 24–2 that could produce fivefold increase in OA production (3.42?±?0.21 mg/l) as compared to the wild strain. This is the first report that germinating spores are applied in marine-derived Penicillium sp. mutating to enhance the production of OA. Further, Plackett–Burman design and central composite design were adopted to optimize the basic medium components for increasing OA production by the mutant SCSIO 24–2 in shake flasks. The results indicated that three medium components including mannitol, maltose, and l-cysteine had significant effects on OA production, and their concentrations were optimized as 36, 27.9, and 0.99 g/l, respectively. In the optimized medium, the OA production (18.31?±?0.27 mg/l) by mutant SCSIO 24–2 was 4.4-fold higher than that in the basic medium. These results of this work promise to improve the present production of OA and may be adopted to enhance other objective products' production by marine-derived fungi.     

CyclinE和p27蛋白在骨肉瘤中的表达及临床意义

目的探讨CyclinE和p27在骨肉瘤中表达及临床意义。方法检测108例骨肉瘤石蜡包埋组织中CyclinE和p27蛋白表达水平,统计分析其与患者临床病理因素和预后之间的关系。结果骨肉瘤组织中CyclinE的阳性率为68．52％,p27的阳性率为26．85％;CyclinE和p27蛋白表达水平与骨肉瘤病理分级、软组织浸润、远处转移、Enneking分期及患者整体生存期有关（P〈0．05）;CyclinE蛋白阳性组骨肉瘤患者5年存活率显著低于阴性组;而p27蛋白阳性组患者5年存活率显著高于阴性组（P〈0．05）。Cox多因素分析提示软组织浸润及远处转移状态、病理分级、Enneking外科分期、CyclinE和p27蛋白表达水平是影响骨肉瘤患者预后的独立危险因素（P〈0．05）。结论CyclinE和p27蛋白表达水平是判断骨肉瘤患者预后的新指标,联合检测CyclinE和p27蛋白表达水平对骨肉瘤的进展、预后判断有重要意义。