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The lgtABCDE Gene Cluster, Involved in Lipooligosaccharide Biosynthesis in Neisseria gonorrhoeae, Contains Multiple Promoter Sequences. Derek C. Braun, 2004.Biosynthesis of the variable core domain of lipooligosaccharide[LOS] in Neisseria gonorrhoeae is mediated by glycosyl transferases encoded by lgtABCDE . Changes within homopolymeric runs within lgtA, lgtC, and lgtD affect the expression state of these genes,with the nature of the LOS expressed determined by the functionalityof these genes . However, the mechanism for modulating the amountof multiple LOS chemotypes expressed in a single cell is notunderstood . Using mutants containing polar disruptions within the lgtABCDE locus, we determined that the expression of this locus is mediated by multiple promoters and that disruptionof transcription from these promoters alters the relative levelsof simultaneously expressed LOS chemotypes . Expression of the lgtABCDE locus was quantified by using xylE transcriptional fusions, and the data indicate that this locus is transcribed in trace amounts and that subtle changes in transcription resultin phenotypic changes . By using rapid amplification of 5' cDNAends, transcriptional start sites and promoter sequences wereidentified within lgtABCDE . Most of these promoters possessed50 to 67% homology with the consensus gearbox promoter sequenceof Escherichia coli. Peptide Nucleic Acid-Mediated Competitive PCR Clamping for Detection of Rifampin-Resistant Mycobacterium tuberculosis. Tomotada Iwamoto, 2004.Peptide nucleic acid-mediated competitive PCR clamping, which can selectively amplify mutant alleles, was developed to detect mutations in four codons (513, 516, 526, and 531) of the rpoB gene in Mycobacterium tuberculosis strains . This simple method successfully identified the mutations in all 40 of the M . tuberculosis strains tested . Secretion of Active-Form Streptoverticillium mobaraense Transglutaminase by Corynebacterium glutamicum: Processing of the Pro-Transglutaminase by a Cosecreted Subtilisin-Like Protease from Streptomyces albogriseolus. Yoshimi Kikuchi, 2003.The transglutaminase secreted by Streptoverticillium mobaraense is a useful enzyme in the food industry . A fragment of transglutaminase was secreted by Corynebacterium glutamicum when it was coupled on a plasmid to the promoter and signal peptide of a cell surface protein from C . glutamicum . We analyzed the signal peptide and the pro-domain of the transglutaminase gene and found that the signal peptide consists of 31 amino acid residues and the pro-domain consists of 45 residues . When the pro-domain of the transglutaminase was used, the pro-transglutaminase was secreted efficiently by C . glutamicum but had no enzymatic activity . However, when the plasmid carrying the S . mobaraense transglutaminase also encoded SAM-P45, a subtilisin-like serine protease derived from Streptomyces albogriseolus, the peptide bond to the C side of 41-Ser of the pro-transglutaminase was hydrolyzed, and the pro-transglutaminase was converted to an active form . Our findings suggest that C . glutamicum has potential as a host for industrial-scale protein production . Ammonia-Oxidizing Bacteria along Meadow-to-Forest Transects in the Oregon Cascade Mountains. A. T. Mintie, 2003.Although nitrification has been well studied in coniferous forests of Western North America, communities of NH3-oxidizing bacteria in these forests have not been characterized . Studies were conducted along meadow-to-forest transects at two sites (Lookout and Carpenter) in the H . J . Andrews Experimental Forest, located in the Cascade Mountains of Oregon . Soil samples taken at 10- or 20-m intervals along the transects showed that several soil properties, including net nitrogen mineralization and nitrification potential rates changed significantly between vegetation zones . Nonetheless, terminal restriction fragment length polymorphism (T-RFLP) analysis of the PCR-amplified NH3 monooxygenase subunit A gene (amoA) showed the same DNA fragments (TaqI [283 bp], CfoI [66 bp], and AluI [392 bp]) to dominate  45 of 47 soil samples recovered from both sites . Two fragments (491-bp AluI [AluI491] and CfoI135) were found more frequently in meadow and transition zone soil samples than in forest samples at both sites . At the Lookout site the combination AluI491-CfoI135 was found primarily in meadow samples expressing the highest N mineralization rates . Four unique amoA sequences were identified among 15 isolates recovered into pure culture from various transect locations . Six isolates possessed the most common T-RFLP amoA fingerprint of the soil samples (TaqI283-AluI392-CfoI66), and their amoA sequences shared 99.8% similarity with a cultured species, Nitrosospira sp. strain Ka4 (cluster 4) . The other three amoA sequences were most similar to sequences of Nitrosospira sp. strain Nsp1 and Nitrosospira briensis (cluster 3) . 16S ribosomal DNA sequence analysis confirmed the affiliation of these isolates with Nitrosospira clusters 3 and 4 . Two amoA clone sequences matched T-RFLP fingerprints found in soil, but they were not found among the isolates .
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