Home About us Contact
|
Home About us Contact | ||
|
|
||
Insertion Sequence (insertion + sequence)
Selected AbstractsPalladium-Catalyzed Carbonylation/Acyl Migratory Insertion Sequence,ANGEWANDTE CHEMIE, Issue 6 2010Zhenhua Zhang Hoch effizient entstehen ,-Oxoester, -ketone und -enone durch die Titelsequenz in einer palladiumkatalysierten Reaktion von Aryliodiden mit Diazoverbindungen oder N -Tosylhydrazonen und Kohlenmonoxid (siehe Schema; DCE=1,2-Dichlorethan). [source] ChemInform Abstract: Palladium-Catalyzed Carbonylation/Acyl Migratory Insertion Sequence.CHEMINFORM, Issue 21 2010Zhenhua Zhang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Heterologous expression and characterization of the exopolysaccharide from Streptococcus thermophilus Sfi39FEBS JOURNAL, Issue 19 2001Jacques-Edouard Germond The genes responsible for exopolysaccharide (EPS) synthesis in Streptococcus thermophilus Sfi39 were identified on a 20-kb genomic fragment. The two genes, epsE and epsG, were shown to be involved in EPS synthesis as their disruption lead to the loss of the ropy phenotype. Several naturally selected nonropy mutants were isolated, one acquired an insertion sequence (IS)-element (IS905) in the middle of the eps gene cluster. The eps gene cluster was cloned and transferred into a nonEPS-producing heterologous host, Lactococcus lactis MG1363. The EPS produced was shown by chemical analysis and NMR spectroscopy to be identical to the EPS produced by S. thermophilus Sfi39. This demonstrated first that all genes needed for EPS production and export were present in the S. thermophilus Sfi39 eps gene cluster, and second that the heterologous production of an EPS was possible by transfer of the complete eps gene cluster alone, provided that the heterologous host possessed all necessary genetic information for precursor synthesis. [source] Carbofuran degradation mediated by three related plasmid systemsFEMS MICROBIOLOGY ECOLOGY, Issue 3 2000A.V. Ogram Abstract Two carbofuran-metabolizing Sphingomonas strains, TA and CD, were isolated from soils with differing histories of exposure to carbofuran. These strains were compared with a previously described strain, Sphingomonas sp. CFO6, with regard to growth rate, formation of metabolites, and plasmid content and structure. Extensive regions of similarity were observed between the three different plasmid systems as evidenced by cross hybridization. In addition, all three systems harbor IS1412, an insertion sequence (IS) element involved in heat-induced loss of carbofuran phenotype in CFO6, and heat-induced carbofuran deficient mutants of all three strains correlated with loss of IS1412. A carbofuran deficient mutant of TA generated by induction of IS elements was complemented by reintroduction of the wild-type plasmid, confirming the presence of genes required for carbofuran metabolism on this plasmid. Carbofuran metabolism in these three strains is clearly linked via plasmids of different numbers and sizes that share extensive common regions, and carbofuran-degrading genes may be associated with active IS elements. [source] Analysis of a Leptospira interrogans locus containing DNA replication genes and a new IS, IS1502FEMS MICROBIOLOGY LETTERS, Issue 2 2002R.L. Zuerner Abstract A region of the Leptospira interrogans serovar pomona genome encoding DNA replication genes was characterized. This region, designated the ppa-ntrC locus, includes 19 open reading frames and a new insertion sequence, IS1502. Although this locus resembles replication origins from many eubacteria, it lacks several genes common to homologous loci. Some replication-related genes were previously located near rrf, and may have been moved to that location by homologous recombination between short sequence elements common to both loci. Further analysis showed that the ppa-ntrC region has undergone substantial change during spirochete evolution. Transcription analysis using RT-PCR revealed uniquely organized polycistronic mRNAs in the ppa-ntrC locus. The dnaN and recF intergenic region of serovar pomona was different from the homologous sites of 41 L. interrogans serovars by the presence of IS1502. The distribution of IS1502 throughout pathogenic Leptospira species varies. This result suggests that IS1502 may have been recently introduced into Leptospira. [source] Selenium metabolism in zebrafish: multiplicity of selenoprotein genes and expression of a protein containing 17 selenocysteine residuesGENES TO CELLS, Issue 12 2000Gregory V. Kryukov Fish are an important source of selenium in human nutrition and the zebrafish is a potentially useful model organism for the study of selenium metabolism and its role in biology and medicine. Selenium is present in vertebrate proteins in the form of selenocysteine (Sec), the 21st natural amino acid in protein which is encoded by UGA. We report here the detection of 18 zebrafish genes for Sec-containing proteins. We found two zebrafish orthologs of human SelT, glutathione peroxidase 1 and glutathione peroxidase 4, and single orthologs of several other selenoproteins. In addition, new zebrafish selenoproteins were identified that were distant homologues of SelP, SelT and SelW, but their direct orthologs in other species are not known. This multiplicity of selenoprotein genes appeared to result from gene and genome duplications, followed by the retention of new selenoprotein genes. We found a zebrafish selenoprotein P gene (designated zSelPa) that contained two Sec insertion sequence (SECIS) elements and encoded a protein containing 17 Sec residues, the largest number of Sec residues found in any known protein. In contrast, a second SelP gene (designated zSelPb) was also identified that contained one SECIS element and encoded a protein with a single Sec. We found that zSelPa could be expressed and secreted by mammalian cells. The occurrence of zSelPa and zSelPb suggested that the function of the N-terminal domain of mammalian SelP proteins may be separated from that of the C-terminal Sec-rich sequence: the N-terminal domain containing the UxxC motif is likely involved in oxidoreduction, whereas the C-terminal portion of the protein may function in selenium transport or storage. Our data also suggest that the utilization of Sec is more common in zebrafish than in previously characterized species, including mammals. [source] Stability of recombinant plasmids on the continuous culture of Bifidobacterium animalis ATCC 27536BIOTECHNOLOGY & BIOENGINEERING, Issue 2 2003Antonio González Vara Abstract Bifidobacterium animalis ATCC 27536 represents among bifidobacteria a host-model for cloning experiments. The segregational and structural stabilities of a family of cloning vectors with different molecular weights but sharing a common core were studied in continuous fermentation of the hosting B. animalis without selective pressure. The rate of plasmid loss (R) and the specific growth rate difference (,,) between plasmid-free and plasmid-carrying cells were calculated for each plasmid and their relationship with plasmid size was studied. It was observed that both R and the numerical value of ,, increased exponentially with plasmid size. The exponential functions correlating the specific growth rate difference and the rate of plasmid loss with the plasmid molecular weight were determined. Furthermore, the smallest of the plasmids studied, pLAV (4.3-kb) was thoroughly characterized by means of its complete nucleotide sequence. It was found that it contained an extra DNA fragment, the first bifidobacterial insertion sequence characterised, named IS 1999. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 145,150, 2003. [source] Prevalence and diversity of insertion sequences in the genome of Bacillus thuringiensis YBT-1520 and comparison with other Bacillus cereus group membersFEMS MICROBIOLOGY LETTERS, Issue 1 2010Ning Qiu Abstract Members of the Bacillus cereus group are closely related bacteria that exhibit highly divergent pathogenic properties. Sequencing of Bacillus thuringiensis ssp. kurstaki strain YBT-1520 revealed an increased number of insertion sequences (ISs) compared with those of the published B. cereus group genomes. Although some of these ISs have been observed and summarized in B. thuringiensis previously, a genomic characterization of their content is required to reveal their distribution and evolution. The result shows that the larger number of transposase coding genes on YBT-1520 chromosome is mainly caused by the amplification of IS231C, IS232A and ISBth166. Some functional genes have been disrupted through the insertion of ISs, preferentially IS231C. By comparing the Southern hybridization profiles of different B. thuringiensis strains, the existence of ISBth166 was mainly found in serovar kurstaki and the recent expansion of IS231C between different kurstaki isolates was suggested. In addition to revealing the ISs profile in YBT-1520 as well as the comparison in the B. cereus group, this study will contribute to further comparative analyses of multiple B. thuringiensis strains aimed at understanding the IS-mediated genomic rearrangements among them. [source] New insertion sequences of Sulfolobus: functional properties and implications for genome evolution in hyperthermophilic archaeaMOLECULAR MICROBIOLOGY, Issue 1 2005Zachary D. Blount Summary Analyses of complete genomes indicate that insertion sequences (ISs) are abundant and widespread in hyperthermophilic archaea, but few experimental studies have measured their activities in these hosts. As a way to investigate the impact of ISs on Sulfolobus genomes, we identified seven transpositionally active ISs in a widely distributed Sulfolobus species, and measured their functional properties. Six of the seven were found to be distinct from previously described ISs of Sulfolobus, and one of the six could not be assigned to any known IS family. A type II ,Miniature Inverted-repeat Transposable Element' (MITE) related to one of the ISs was also recovered. Rates of transposition of the different ISs into the pyrEF region of their host strains varied over a 250-fold range. The Sulfolobus ISs also differed with respect to target-site selectivity, although several shared an apparent preference for the pyrEF promoter region. Despite the number of distinct ISs assayed and their molecular diversity, only one demonstrated precise excision from the chromosomal target region. The fact that this IS is the only one lacking inverted repeats and target-site duplication suggests that the observed precise excision may be promoted by the IS itself. Sequence searches revealed previously unidentified partial copies of the newly identified ISs in the Sulfolobus tokodaii and Sulfolobus solfataricus genomes. The structures of these fragmentary copies suggest several distinct molecular mechanisms which, in the absence of precise excision, inactivate ISs and gradually eliminate the defective copies from Sulfolobus genomes. [source] Biochemical and genetic bases of dehalorespirationTHE CHEMICAL RECORD, Issue 1 2008Taiki Futagami Abstract Some anaerobic bacteria can efficiently eliminate one or more halide atoms from halogenated compounds such as chlorophenols and chloroethenes through reductive dehalogenation. During this process, the bacteria utilize halogenated compounds as the terminal electron acceptors in their anaerobic respiration, called dehalorespiration, to yield energy for growth. Currently the genera of Desulfitobacterium and Dehalococcoides occupy the major part of the dehalorespiring isolates. The former can acquire energy not only by dehalorespiration but also by other respirations utilizing organic compounds and metals. In sharp contrast, the latter is specialized in dehalorespiration and plays a crucial role in the detoxification of chlorinated compounds in nature. From these bacteria, various reductive dehalogenases, which catalyze the dehalogenation reaction, were purified and their corresponding genes were identified. Most reductive dehalogenases exhibit similar features such as the presences of a Tat (twin arginine translocation) signal sequence, two Fe-S clusters, and a corrinoid cofactor. Some of dehalogenase-encoding genes are found to be flanked by insertion sequences. Thus, dehalogenase genes act as a catabolic transposon, and genetic rearrangements mediated by transposable elements occur well in dehalorespirers. Moreover, the genome sequences of some dehalorespiring bacteria provide many insights into the mechanism of dehalorespiration and the evolution of a dehalogenase gene. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 1,12; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20134 [source] | |||||||||||||