Expulsion of selenium/protein nanoparticles through vesicle-like structures by Saccharomyces cerevisiae under microaerophilic environment

Nano-selenium/protein is a kind of lower toxic supplement to human. Many microorganisms can reduce selenite/selenate to intracellular or extracellular selenium nanoparticles. This study examined the influence of dissolved oxygen on the expulsion of extracellular selenium/protein produced in Saccharomyces cerevisiae. More of the added selenite was reduced to extracellular selenium nanoparticles by yeast cells only under oxygen-limited condition than under aerobic or anaerobic condition. For the first time, we evidenced that selenium/protein nanoparticles synthesized in vivo were transported out of the cells by vesicle-like structures under microaerophilic environment. The characterizations of the extracellular spherical selenium/protein nanoparticles were also examined by SEM, TEM, EDX and FTIR.     

几种红树植物幼苗中可溶性糖的含量

用Ｓｏｍｏｇｙｉ法测定了红海榄、木榄和秋茄３种红树植物幼苗的根、茎、叶和胚轴中可溶性糖的含量。同时．进行了加样回收率试验,回收率平均为１００．４８％,变异系数为２．１４％     

Effects and mechanism of Chinese tarantula toxins on the Kv2.1 potassium channels

Three neurotoxins, Jingzhaotoxin-I, -III, and -V (JZTX-I, -III, and -V), isolated from the venom of the Chinese tarantula Chilobrachys Jingzhao, are 29-36-amino acid peptides. Electrophysiological recordings carried out in Xenopus laevis oocytes show that these toxins acted as gating modifier of voltage-dependent K+ channels. They slow the rate of Kv2.1 channel activation and increase the tail current deactivation, suggesting that toxin-bound channels can still open but are modified. JZTX-III selectively inhibits Kv2.1 channels, and JZTX-V exhibits a higher affinity to Kv4.2 channels than to Kv2.1 channels, whereas JZTX-I inhibits Kv2.1 and Kv4.1 channels with low affinity. Structure-function analysis indicates that electrostatic interactions can benefit for toxin affinity and the feature of electrostatic anisotropy may be correlated with the different affinity of the toxins for the Kv2.1 and Kv4.1 channels. Furthermore, phylogenetic analysis of these and other gating modifiers provides clues for the exploration of toxin-channel interaction.     

极端耐盐放线菌白色普氏菌YIM 90005T四氢嘧啶及5-羟基四氢嘧啶合成相关基因的克隆

摘要：【目的】 为了研究耐盐放线菌对高盐环境的适应机理。【方法】 用HPLC定量检测了极端耐盐、丝状产孢放线菌——白色普氏菌（Prauserella alba） YIM 90005T在不同盐浓度下胞内相容性溶质的种类和含量。【结果】 结果发现,四氢嘧啶和5-羟基四氢嘧啶是其主要的相容性溶质。在培养基NaCl浓度为10%时,四氢嘧啶在胞内累积浓度最大,为18.77 μg/mg干菌体重。之后随NaCl浓度的升高,胞内的四氢嘧啶含量逐渐减少,而5-羟基四氢嘧啶的含量逐渐增加,在该菌耐受的最高NaCl浓度下（24% w/v）,胞内5-羟基四氢嘧啶含量达到最大值,为22.98 μg/mg干菌体重。设计兼并引物,利用染色体步移,克隆得到四氢嘧啶及5-羟基四氢嘧啶合成相关基因ectABCD。序列分析表明,ectABCD位于一个操纵子中。进一步对不同NaCl浓度培养条件下ectB,D的表达量进行定量分析,结果表明该基因簇表达量随着培养基中NaCl浓度的增加而增大。【结论】 研究结果证实5-羟基四氢嘧啶是P. alba YIM 90005T在极高盐浓度条件下起渗透调节及保护的相容性溶质。     

拟黑多刺蚁成虫头部USP基因的定位与定量分析及其与EcR基因相关性

【目的】超气门蛋白（ultraspiracle protein, USP）是蜕皮激素作用靶标的重要组成部分。本研究拟通过分析在拟黑多刺蚁Polyrhachis vicina Roger USP基因PvUSP在不同品级成虫头部mRNA表达的差异,推测PvUSP对其脑神经功能或行为的影响;拟通过饲喂PvUSP dsRNA对拟黑多刺蚁不同品级成虫PvUSP进行RNA干扰（RNAi）,推测PvUSP对虫体生理功能的影响及其与蜕皮激素受体（ecdysone receptor, EcR）基因PvEcR之间功能的相关性。【方法】利用荧光原位杂交及荧光实时定量PCR技术对拟黑多刺蚁不同品级成虫头部PvUSP mRNA组织分布与表达水平进行检测;通过饲喂PvUSP dsRNA对拟黑多刺蚁不同品级成虫PvUSP进行RNAi,采用荧光实时定量PCR检测拟黑多刺蚁PvUSP与PvEcR表达水平的变化。【结果】PvUSP mRNA广泛表达于拟黑多刺蚁不同品级成虫头部（主要分布于蕈形体）,不同品级成虫头部PvUSP mRNA的表达量不同,工蚁头部表达量最高,雄蚁头部次之,雌蚁头部的表达量最低;RNAi沉默PvUSP后,与对照组相比,PvUSP mRNA在不同品级拟黑多刺蚁成虫体内表达量均明显降低,并存在显著差异(P<0.01);与对照组相比,PvEcR mRNA在各品级表达量均有增加,工蚁和雄蚁表达量变化不显著（P>0.05）,但雌蚁体内PvEcR mRNA表达量显著增加（P<0.05）。【结论】PvUSP基因对拟黑多刺蚁不同品级头部神经系统的构建、功能作用的发挥有关;拟黑多刺蚁PvUSP基因与PvEcR基因可能在异源二聚体形成过程中存在关联性或功能的互补性;PvUSP可能对雌蚁的生殖功能产生重要影响。     

Proteomic analysis of human gastric juice: a shotgun approach

Gastric juice is the most proximal fluid surrounding the stomach tissue. The analysis of gastric juice protein contents will thus be able to accurately reflect the pathophysiology of the stomach. This biological fluid is also a potential reservoir of secreted biomarkers in higher concentration as compared to the serum. Unlike the rest of the gastrointestinal fluids, there were very few studies reported on gastric juice proteome. To date, the proteins that routinely populate this biofluid are largely unknown. This is partly due to the technical difficulties in processing a sample that contains a collection of other gastrointestinal fluids, especially saliva. In this study, we attempt to profile the protein components of the gastric fluids from chronic gastritis patients using a direct shotgun proteomics approach. These data represent the first report of the proteome of human gastric juice with gastritis background.     

Vero细胞和脊髓灰质炎病毒在无血清条件下的培养探究

目的：探索Vero细胞和脊髓灰质炎病毒在无血清条件下的最佳培养条件,为无血清培养Vero细胞生产脊髓灰质炎疫苗奠定基础。方法选择直接适应（直降组）和序贯适应（驯化组）两种无血清培养方法,观察Vero细胞和脊髓灰质炎病毒在无血清条件下的生长情况,并检测脊髓灰质炎病毒及其病毒滴度。结果 Vero细胞在两种无血清条件下均生长良好,其中驯化组细胞生长速度更接近对照组。以脊髓灰质炎病毒Sabin株Ⅰ型分别感染直降组、驯化组和对照组细胞的病毒滴度平均值分别为8．94、8．81和8．94 LgCCID50/mL;Ⅱ型病毒滴度平均值分别为8．84、8．25和7．94 LgCCID50/mL;Ⅲ型病毒滴度平均值分别为8．91、8．57和8．63 LgCCID50/mL;且3组的变异系数（ CV）均小于10％。结论 Vero细胞在无血清条件下生长良好,无血清培养的Vero 细胞可用作脊髓灰质炎疫苗生产的基质。     

益生菌与宿主疾病关系的研究进展

人类肠道中含有的多种微生物,称为肠道菌群,它们对宿主的健康起着至关重要的作用。肠道菌群的组成包括细菌、病毒和真核生物,已经被证明与宿主健康有密切的联系,尤其是其中的益生菌。益生菌通过多种途径发挥作用,包括与宿主微生物的相互作用、抵御病原菌的定殖、改善肠道屏障功能、调节免疫功能、产生相关代谢产物,在宿主的代谢、免疫和神经系统中发挥有益作用。综述益生菌的作用机制,讨论了近年来益生菌应用临床研究实例以更好地理解其对疾病风险和健康可持续性的贡献,将为新的治疗干预和疾病预防策略提供参考。