煤附生真菌产漆酶菌株的分离鉴定及产酶特性研究

从煤炭样品中筛选到一株产漆酶活性菌株,经菌体形态观察和ITS序列分析,鉴定为Trichoderma asperellum W03。菌株所产漆酶的最适反应pH为3.5-4.5,最适反应温度45℃,类似于白腐真菌漆酶。液态发酵条件的均匀设计实验表明,适宜的发酵培养基组成为:土豆200.00g/L、葡萄糖9.36g/L、米糠粉37.44g/L、硝酸钾4.00g/L、KH2PO43.20g/L、MgSO4·7H2O2.00g/L、CuSO4·5H2O0.005g/L、初始pH8.0;在33℃、180r/min、50mL/250mL的摇瓶培养条件下,棘孢木霉W03在孢子接种培养后48h、84h产酶量较高,分别处在菌体的快速生长期和衰亡期;菌体产酶受Cu2+、联苯胺诱导,而受1-萘酚、愈创木酚和2,4-D抑制。     

小叶章种群地上生物量生长量及其时间序列分析

本文通过对三江平原典型草甸、沼泽化草甸及沼泽群落的优势种群-小叶章种群地上生物量生长量及其时间序列的分析表明:典型草甸小叶章种群地上生物量生长量季节动态呈"W"型。另两个类型呈双峰型。其累积生长量均呈单峰型,且在整个生长季,干物质均有一定程度的积累,时间序列分析也验证了上述变化趋势。     

SNUFER: A software for localization and presentation of single nucleotide polymorphisms using a Clustal multiple sequence alignment output file

SNUFER is a software for the automatic localization and generation of tables used for the presentation of single nucleotide polymorphisms (SNPs). After input of a fasta file containing the sequences to be analyzed, a multiple sequence alignment is generated using ClustalW ran inside SNUFER. The ClustalW output file is then used to generate a table which displays the SNPs detected in the aligned sequences and their degree of similarity. This table can be exported to Microsoft Word, Microsoft Excel or as a single text file, permitting further editing for publication. The software was written using Delphi 7 for programming and FireBird 2.0 for sequence database management. It is freely available for noncommercial use and can be downloaded from http://www.heranza.com.br/bioinformatica2.htm.     

荒漠绿洲过渡带沙拐枣种群结构及动态特征

沙拐枣(Calligonum mongolicum)作为黑河中游荒漠绿洲过渡带的一种主要固沙植物种,它对于维护荒漠绿洲过渡带生态系统的稳定性起到了至关重要的作用。通过样地调查和数据统计,绘制了沙拐枣种群的径级结构图,在此基础上编制了种群的特定时间生命表,分析了存活曲线、死亡率曲线等重要参数,并运用时间序列模型预测种群数量动态,以揭示荒漠绿洲过渡带沙拐枣种群的结构及动态特征。结果表明:沙拐枣种群属于增长型,Vpi'=0.0233,表明该种群趋近于稳定型,但沙拐枣种群Ⅰ、Ⅱ龄级个体数目少于Ⅲ龄级的个体数目;存活曲线趋于Deevey-Ⅱ,各龄级种群有相近的死亡率;时间序列预测分析表明,在未来2、4、6、8个龄级时间后沙拐枣老龄个体逐渐增多,幼龄株数则有所降低,种群稳定性长期维持困难,因此,适当的人工辅助恢复和现有植株及生境的保护是保持沙拐枣种群自然更新和种群恢复的关键。     

白粉病菌诱导的小麦表达序列标签(EST)研究(英)

白粉病是我国小麦的主要病害之一。尝试用表达序列标签 (expressedsequencetags,EST)技术 ,研究了经白粉病菌诱导后的小麦基因表达。从构建的普通cDNA文库中随机挑取约 15 0 0个阳性克隆并进行测序 ,获不重复ESTs序列 387条。不重复序列均获GenBank的存储号。其中 4 9.4 %的序列与已知基因同源 ,196条序列功能未知 ,84条序列为新ESTs。将不重复序列制备成高密度点阵膜 ,用差示杂交法筛选到几个抗病相关序列。     

水稻条纹叶枯病毒分子生物学的研究——Ⅲ.外壳蛋白基因的序列分析

以含有水稻条纹叶枯病毒(RSV)外壳蛋白(CP)基因的重组克隆为材料,将RSV-cDNA酶解后,亚克隆人M13mp18、19,采用双脱氧链终止法测序得到RSV-CP基因的全长序列(共含966bp),同日本已发表的RSV-CP基因序列相比同源率达97％。     

Sequence variation in nuclear ribosomal small subunit,internal transcribed spacer and large subunit regions of Rhizophagus irregularis and Gigaspora margarita is high and isolate‐dependent

Arbuscular mycorrhizal (AM) fungi are known to exhibit high intra‐organism genetic variation. However, information about intra‐ vs. interspecific variation among the genes commonly used in diversity surveys is limited. Here, the nuclear small subunit (SSU) rRNA gene, internal transcribed spacer (ITS) region and large subunit (LSU) rRNA gene portions were sequenced from 3 to 5 individual spores from each of two isolates of Rhizophagus irregularis and Gigaspora margarita. A total of 1482 Sanger sequences (0.5 Mb) from 239 clones were obtained, spanning ~4370 bp of the ribosomal operon when concatenated. Intrasporal and intra‐isolate sequence variation was high for all three regions even though variant numbers were not exhausted by sequencing 12–40 clones per isolate. Intra‐isolate nucleotide variation levels followed the expected order of ITS > LSU > SSU, but the values were strongly dependent on isolate identity. Single nucleotide polymorphism (SNP) densities over 4 SNP/kb in the ribosomal operon were detected in all four isolates. Automated operational taxonomic unit picking within the sequence set of known identity overestimated species richness with almost all cut‐off levels, markers and isolates. Average intraspecific sequence similarity values were 99%, 96% and 94% for amplicons in SSU, LSU and ITS, respectively. The suitability of the central part of the SSU as a marker for AM fungal community surveys was further supported by its level of nucleotide variation, which is similar to that of the ITS region; its alignability across the entire phylum; its appropriate length for next‐generation sequencing; and its ease of amplification in single‐step PCR.     

Degradation of N-acyl homoserine lactone quorum sensing signal molecules by forest root-associated fungi

A collection of mycorrhizal and nonmycorrhizal root-associated fungi coming from forest environments was screened for their ability to degrade N-acyl homoserine lactones (AHL) or to prevent AHL recognition by producing quorum sensing inhibitors (QSI). No production of QS-inhibitors or -activators was detected using the two biosensors Chromobacterium violaceum CV026 and Agrobacterium tumefaciens in the culture supernatant of these fungi. However, the ability to degrade C6- and 3O,C6-HSL was detected for three fungal isolates. Acidification assay revealed that the AHL were degraded by a lactonase activity for two of these isolates. These results demonstrated for the first time that the forest root-associated fungi are capable of degrading the AHL signal molecules.     

A conserved α helix of Bcs1, a mitochondrial AAA chaperone,is required for the Respiratory Complex III maturation

Bcs1 is a transmembrane chaperone in the mitochondrial inner membrane, and is required for the mitochondrial Respiratory Chain Complex III assembly. It has been shown that the highly-conserved C-terminal region of Bcs1 including the AAA ATPase domain in the matrix side is essential for the chaperone function. Here we describe the importance of the N-terminal short segment located in the intermembrane space in the Bcs1 function. Among the N-terminal 44 amino acid residues of yeast Bcs1, the first 37 residues are dispensable whereas a hydrophobic amino acid in the residue 38 is essential for integration of Rieske Iron-sulfur Protein into the premature Complex III from the mitochondrial matrix. Substitution of the residue 38 by a hydrophilic amino acid residue affects conformation of Bcs1 and interactions with other proteins. The evolutionarily-conserved short α helix of Bcs1 in the intermembrane space is an essential element for the chaperone function.     

RNA-protein interactions at the initial and terminal stages of protein biosynthesis as investigated by Lev Kisselev (On the occasion of his 70th anniversary)

This review highlights studies by Lev L. Kisselev and his colleagues on the initial and terminal stages of protein biosynthesis, which cover the period of the last 45 years (1961-2006). They investigated spatial structure of tRNAs, structure and functions of aminoacyl-tRNA-synthetases of higher organisms, and the final step of protein synthesis, termination of translation. L. Kisselev and his team have made three major contributions to these fields of molecular biology; (i) they proposed the hypothesis on the role of anticodon triplet of tRNA in recognition by cognate aminoacyl-tRNA synthetase, which has been experimentally confirmed and is now included in textbooks; (ii) identified primary structures and functions of two eukaryotic protein factors (eRF1 and eRF3) playing a pivotal role in translation termination; (iii) characterized a structural basis for stop codon recognition by eRF1 within the ribosome and discovered the negative structural elements of eRF1, limiting its recognition of one or two stop-codons.