Overexpression of formate dehydrogenase inArabidopsis thaliana resulted in plants tolerant to high concentrations of formate

The potential role played by formate dehydrogenase (FDH) in formate metabolism has been examined by the overexpression of FDH in Arabidopsis thaliana. Three independent transgenic lines were selected and shown to produce elevated amounts of FDH protein with a corresponding elevated FDH activity (2.5-5 fold) over wild-type (WT) plants. Under normal growth conditions, no altered phenotype was observed in these transgenic plants; in growth media supplied with formate, however, significant differences in shoot and root growth, compared to that of WT plants, were observed. WT plants were severely injured if grown in the presence of 16 mmol/L formate, while the transgenic plants were able to grow well. Formate delayed germination of both WT and transgenic seeds at concentrations above 4 mmol/L, but both types of seeds were eventually able to complete more than 95 % germination even at 32 mmol/L formate. Formate markedly inhibited primary root elongation, and its inhibitory action on WT was much stronger than on transgenic plants. Different formate salts affected root elongation similarly, indicating that the formate ion was the major factor inhibiting root growth. Sodium acetate (NaAc), an analogue of formate, also inhibited root elongation, but its action on WT and transgenic plants was the same, indicating that tolerance of transgenic plants to formate toxicity was specific. Transgenic plants showed no significant tolerance to the toxicity of two other one-carbon metabolites, methanol and formaldehyde. A role for FDH in detoxifying formate is proposed.     

符号检验法及其在动物生态学研究中的应用

符号检验法是非参数统计法的一种重要方法,在动物生态学的实验数据统计分析领域有一定的实用价值,本文简要介绍这一方法的使用。     

木瓜榕上昆虫群落结构及分布特征

对西双版纳热带雨林木瓜榕上的昆虫群落结构和分布特征进行了研究。结果表明：样地内共采集到木瓜榕树上昆虫48974号,隶属9个目,30个科,56属,70种。主要是鞘翅目、鳞翅目、膜翅目、同翅目、双翅目、等翅目、半翅目、脉翅目和缨翅目的科、属和种类。属和种以鞘翅目和膜翅目类群最丰富;个体数量是膜翅目最多, 高达68.79%, 其中56.58%是传粉类昆虫。从垂直分布规律看：种类和数量是老茎结果部位最高,占71.34%, 在青果期和熟果期表现最丰富;树冠与叶片部位次之,比率为15.68%;根部再次之(9.55%);枝杈和主干最低, 仅占3.42%。在不同季节中,雨季的种类和个体数量最高,为35.96%;干热季节次之(34.22%),干凉季节最低(29.82%)。     

细胞壁缺陷型淋病奈瑟菌cppB基因的检测

目的：了解细胞壁缺陷对淋病奈瑟菌隐蔽性质粒B基因（cppB）的影响。方法：用青霉素诱导林病奈瑟菌成L型,以非高渗液体培养基传代培养并获得L型纯培养物,用cppB基因特异性引物以聚合酶链反应（PCR）检测不同代次稳定L型纯培养物的cppB基因。结果：淋病奈瑟菌细菌型及其传1-4代的L型培养物具有cppB基因,传5代后的L型培养物不能检出cppB基因。结论：细胞壁缺陷可造成淋病奈瑟菌隐蔽性质粒丢失,导致cppB基因PCR检测漏诊。     

激光对玉米陈种子萌发的生物效应

用不同剂量的He-Ne激光辐照贮存三年的玉米种子。结果表明,适宜的激光可有效地提高玉米陈种子的发芽势、发芽率和降低种子浸出液的电导率。     

Soil Algae in Brown Coal and Lignite Post-Mining Areas in Central Europe (Czech Republic and Germany)

Algal communities were investigated in two contrasting chronosequences established on reclaimed spoils in the west Bohemian brown coal mining district near Sokolov (Czech Republic) and in the Lusatian lignite mining district near Cottbus (Germany). The Sokolov chronosequence was characterized by tertiary cypric clay substrate, afforestation with Alnus glutinosa (L.) Gaertn., and high pH of deposited spoil material, Cottbus chronosequence by tertiary carboniferous and pyritic sand of extremely low pH ameliorated by fly ash, and afforestation with Pinus sylvestris L. and P. nigra Arnold. A total of 122 species of algae was found in both areas. Although the same species number (80) was identified from Sokolov and Cottbus, both proportion of individual algal groups and species composition were different. Green algae prevailed in both areas, but in Sokolov cyanobacteria and diatoms were also quite diverse, and in younger sites they were also abundant. Total abundance of algae ranged mostly between 10⁴–10⁷ cells/g dry soil, and was one order higher in Cottbus than in Sokolov. Species number was high in young sites, decreased with increasing age, and was the lowest in control forests. In Sokolov, the highest abundance was recorded in the youngest alder plantation. In Cottbus, sludge and compost fertilization used in the youngest pine plantations resulted in rapid formation of visible algal crusts dominated by Klebsormidium crenulatum (Kütz) Lokhorst.     

Soil Microfungi in Two Post-Mining Chronosequences with Different Vegetation Types

Soil microfungi were studied in the Sokolov (Czech Republic) post‐mining dumps afforested with Alnus glutinosa and in the Lusatian (Germany) post‐mining dumps afforested with Pinus sylvestris or P. nigra. Microfungi were isolated using the soil dilution plate method. Soil microfungi communities of two chronosequences were compared by species composition, frequency of species occurrence, and colony forming units of fungi (CFU‐counts). Differences in species occurrence were determined. More species of entomopathogenic microfungi were found from the Sokolov post‐mining area in comparison with the Cottbus post‐mining area. Absidia glauca, A. cylindrospora, Penicillium glabrum, and P. janthinellum were the most frequently isolated species from the Cottbus post‐mining area, while A. glauca, Geomyces pannorum, and Trichoderma koningii predominated at the Sokolov post‐mining area.     

Assembly and regulation of the cytokinetic apparatus in budding yeast

The identification of an actomyosin-based contractile ring in budding yeast has recently established this organism as a general model for studying cytokinesis. Work over the past three years has provided important new insights into the conserved mechanisms underlying the assembly and regulation of the cytokinetic structures. This review covers the recent progress in studying cytokinesis in budding yeast.     

对小鼠ES细胞进行特异性的标记

虽然ES细胞技术的应用十分广泛,对ES细胞多能性本质的研究还不是很深入,体外培养的ES细胞群体的不均一性加大了这方面研究的难度,报道了对ES细胞中特异表达的基因,将报告基因βgeo插入oct-基因转录元件中构建了标记载体pG18NG,转染ES细胞MESPU22和MESPU13后获得了稳定整合的细胞克隆,经体外培养、诱导分化、嵌入体制作等实验,证明利用该载体对ES细胞中的未分化细胞成功进行了标记,该标记在体内、体外都是有效的。     

Force to Divide: Structural and Mechanical Requirements for Actomyosin Ring Contraction

One of the unresolved questions in the field of cell division is how the actomyosin cytoskeleton remains structurally organized while generating the contractile force to divide one cell into two. In analogy to the actomyosin-based force production mechanism in striated muscle, it was originally proposed that contractile stress in the actomyosin ring is generated via a sliding filament mechanism within an organized sarcomere-like array. However, over the last 30 years, ultrastructural and functional studies have noted important distinctions between cytokinetic structures in dividing cells and muscle sarcomeres. Myosin-II motor activity is not always required, and there is evidence that actin depolymerization contributes to contraction. In this Review, the architecture and contractile dynamics of the actomyosin ring at the cell division plane will be discussed. We will report the interdisciplinary advances in the field as well as their integration into a mechanistic understanding of contraction in cell division and in other biological processes that rely on an actomyosin-based force-generating system.