Isolation,identification and characterization of highly tellurite-resistant,tellurite-reducing bacteria from Antarctica

The tellurium oxyanion, tellurite, is extremely noxious to most living organisms. Its toxicity has been mainly related to the generation of reactive oxygen species (ROS) as well as to an unbalancing of the thiol:redox buffering system. Nevertheless, a few bacteria are capable of thriving at high tellurite concentrations. One mechanism of resistance is the enzymatic and non-enzymatic reduction of tellurite to the less toxic elemental tellurium. This reduction generates nano- to micrometric tellurium crystals that display different shapes and sizes.To date, a very limited number of highly tellurite-resistant and tellurite-reducing bacterial species are available from international culture collections. In this work, we decided to look for tellurite-reducing bacteria from an extreme environment, Antarctica. This environment exhibits a combination of several extreme factors such as high UV-radiation and desiccation and freezing conditions that impact directly on the local biodiversity. Since, as does, all these factors induce ROS formation, we hypothesized that Antarctic bacteria could also exhibit tellurite-resistance. In this context, we isolated 123 tellurite-resistant bacteria, and characterized six new tellurite-resistant and tellurite-reducing bacterial strains from samples collected in Antarctica. These strains were identified according to their 16S rRNA gene sequence as Staphylococcus hameolyticus, Staphylococcus sciuri, Acinetobacter haemolyticus, Pseudomonas lini, and two strains of Psychrobacter immobilis.The isolates display tellurite-resistance about 35- to 500-fold higher than Escherichia coli (Te-sensitive organism), and a high level of tellurite reduction which might be interesting for an application in the field of bioremediation or nanoparticle biosynthesis.     

我国萤石资源现状及展望

萤石由于其独特的物理、化学性质，主要用于钢铁、化工、建材三大行业。近年来，化工行业已成为萤石的最大用户。尤其在氟化工方面，用以制造氢氟酸及其衍生物，特别是氟碳化合物，更广泛地应用于各工业部门。不同行业对萤石的质量要求不同，有各自的标准。作为我国外贸的创汇产品，对萤石资源的进一步开发工作仍需重视，制酸级萤石在氟化工生产方面尚具发展潜力。     

Sb2 Te3 纳米结构的制备与表征

以室温热电性能优异的传统热电材料Sb₂Te₃为研究对象,利用化学气相沉积法制备Sb₂Te₃单晶纳米结构,并研究其生长机理.实验结果表明,不加催化剂时Sb₂Te₃易生长成六方纳米盘,在金催化剂条件下定向生长成纳米线.Sb₂Te₃的形貌与其晶体结构和生长机理有关.Sb₂Te₃为三角结构,Sb和