Evaluation of the denitrifying microbiota of anoxic reactors

Removal of inorganic nitrogen compounds from wastewaters can be accomplished by a combination of the biological processes of nitrification and denitrification. The information on the microbiota present in denitrifying reactors is still scarce. In the present work the evaluation of the denitrifying microbiota of different reactor sludges was performed by specific activity measurements and MPN count of denitrifiers. We also present the isolation and physiological and phylogenetic characterisation of denitrifying bacteria from the anoxic reactor of a combined system treating landfill leachate. Specific denitrifying activity measurements were faster to perform and more reliable than MPN enumerations. 16S rDNA characterisation of the isolates showed that they belonged to the genera Thauera, Acidovorax and Alcaligenes and were closely related to microorganisms retrieved from ecosystems rich in recalcitrant compounds. Two of the isolates could grow on aromatic compounds as sole carbon source.     

草甘膦对空心莲子草叶甲Agasicles hygrophila成虫3种代谢酶活性的影响

采用不同浓度的草甘膦0.41 g/L、0.82 g/L、1.23 g/L、1.64g/L、2.05 g/L分别以胃毒和触杀法处理空心莲子草叶甲Agasicles hygrophila成虫,测定其乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)和谷胱甘肽S-转移酶(GSTs)比活力.试验结果表明:两种处理,草甘膦对AChE活力均有不同程度的抑制作用;对CarE活力影响较为显著,在2.05 g/L浓度下,胃毒处理CarE对α-乙酸萘酯(α-NA)和β-乙酸萘酯(β-NA)水解能力分别是对照组的50%和57%,触杀处理CarE对α-乙酸萘酯(α-NA)和β-乙酸荼酯(β-NA)水解能力分别是对照组的53%和59%;胃毒处理埘酶活力影响大于触杀处理,草甘膦对GSTs的活力影响不明显.     

Fe- and S-Metabolizing Microbial Communities Dominate an AMD-Contaminated River Ecosystem and Play Important Roles in Fe and S Cycling

Indigenous Fe- and S-metabolizing bacteria play important roles both in the formation and the natural attenuation of acid mine drainage (AMD). Due to its low pH and Fe-S-rich waters, a river located in the Dabaoshan Mine area provides an ideal opportunity to study indigenous Fe- and S-metabolizing microbial communities and their roles in biogeochemical Fe and S cycling. In this work, water and sediment samples were collected from the river for physicochemical, mineralogical, and microbiological analyses. Illumina MiSeq sequencing indicated higher species richness in the sediment than in the water. Sequencing also found that Fe- and S-metabolizing bacteria were the dominant microorganisms in the heavily and moderately contaminated areas. Fe- and S-metabolizing bacteria found in the water were aerobes or facultative anaerobes, including Acidithiobacillus, Acidiphilium, Thiomonas, Gallionella, and Leptospirillum. Fe- and S-metabolizing bacteria found in the sediment belong to microaerobes, facultative anaerobes, or obligatory anaerobes, including Acidithiobacillus, Sulfobacillus, Thiomonas, Gallionella, Geobacter, Geothrix, and Clostridium. Among the dominant genera in the sediment, Geobacter and Geothrix were rarely detected in AMD-contaminated natural environments. Canonical correspondence analysis indicated that pH, S, and Fe concentration gradients were the most important factors in structuring the river microbial community. Moreover, a scheme explaining the biogeochemical Fe and S cycling is advanced in light of the Fe and S species distribution and the identified Fe- and S-metabolizing bacteria.     

Reciprocal influence of connexins and apical junction proteins on their expressions and functions

Membranes of adjacent cells form intercellular junctional complexes to mechanically anchor neighbour cells (anchoring junctions), to seal the paracellular space and to prevent diffusion of integral proteins within the plasma membrane (tight junctions) and to allow cell-to-cell diffusion of small ions and molecules (gap junctions). These different types of specialised plasma membrane microdomains, sharing common adaptor molecules, particularly zonula occludens proteins, frequently present intermingled relationships where the different proteins co-assemble into macromolecular complexes and their expressions are co-ordinately regulated. Proteins forming gap junction channels (connexins, particularly) and proteins fulfilling cell attachment or forming tight junction strands mutually influence expression and functions of one another.     

Poplar genomics is getting popular: the impact of the poplar genome project on tree research

Trees, due to their long life-span, have characteristics that distinguish them from annual, herbaceous plants. It is likely that many of these properties are based on a tree-specific genetic foundation. The U.S. Department of Energy initiated a genome-sequencing project for Populus, a model perennial plant. Through international collaboration and input to the sequencing effort, the annotated whole genome sequence of Populus trichocarpa will be released to the public in early 2004. This genomic resource will, for the first time, allow comparison between a perennial and an annual plant on a whole genome basis and therefore provide clues for molecular research on tree-specific questions like dormancy, development of a secondary cambium, juvenile-mature phase change, or long-term host-pest interactions. The approximately 520 Mbp of annotated genomic sequence will complement and expand the knowledge provided so far by the 125,000 ESTs from poplar that are available in public databases. This article introduces the international poplar research programmes and points out the significance of the poplar genome project for plant research.     

大粉瘤菌小亚基rDNA片段的克隆测序

对大粉瘤菌Lycogalaflavofuscum的19SrDNA片段进行了克隆测序,序列长度为1443bp。同时将之与多头绒泡菌的相应序列进行了比较,其序列同源性为58.16%。     

Large-scale production of a therapeutic protein in transgenic tobacco plants: effect of subcellular targeting on quality of a recombinant dog gastric lipase

A recombinant dog gastric lipase with therapeutic potential for the treatment of exocrine pancreatic insufficiency was expressed in transgenic tobacco plants. We targeted the protein using two different signal sequences for either vacuolar retention or secretion. In both cases, an active glycosylated recombinant protein was obtained. The recombinant enzymes and the native enzyme displayed similar properties including acid resistance and acidic optimum pH. The proteolytic maturation and the specific activity of the recombinant proteins, however, were found to be dependent on subcellular compartmentalization. Expression levels of recombinant dog gastric lipase were about 5% and 7% of acid extractable plant proteins for vacuolar retention and secretion respectively. This expression system already has allowed the production of tens of grams of purified lipase through open-field culture of transgenic tobacco plants.     

Strategic mining of cyanobacterial patents from the USPTO patent database and analysis of their scope and implications

Patent analysis with the help of the strategic mining of patents from databases is important and useful within the framework of application-oriented research and its commercialization. In the analysis reported here, we have mined cyanobacterial patents from the patent database of the United States Patent and Trademark Office (USPTO). In order to make an assessment of the commercial potentials of cyanobacteria, we conducted the patent search (from 1976 to April 2006) using certain generic terms and the 84 genera of cyanobacteria as keywords. The search was performed in two major ways – searching the abstracts and claims of the patents cumulatively and searching the entire patent documents by the mode of ‘all fields’ in USPTO. In the abstract- and claims-based search, 234 patents were obtained after the removal of overlapping patents among the keywords. An additional 31 patents were added following the ‘all fields’ search; these patents were not covered in the search that was based on abstracts and claims. The entire package of 265 patents, of which 244 were related to cyanobacteria, was then analyzed. Information derived from these patents identified five major areas of cyanobacterial utilization. Cyanobacteria have been patented as a source of a wide spectrum of products, for medical, agriculture and environmental applications, for gene-based products, for methods of cultivation and for methods of control. The chronological development in granting cyanobacterial patents was also traced. This study demonstrates that such strategic mining and analysis of patent data can be used as an index for future development.     

Sequence and structure space of RNA-binding peptides

Studies of RNA-binding peptides, and recent combinatorial library experiments in particular, have demonstrated that diverse peptide sequences and structures can be used to recognize specific RNA sites. The identification of large numbers of sequences capable of binding to a particular site has provided extensive phylogenetic information used to deduce basic principles of recognition. The high frequency at which RNA-binding peptides are found in large sequence libraries suggests plausible routes to evolve sequence-specific binders, facilitating the design of new binding molecules and perhaps reflecting characteristics of natural evolution.