Search results for "Base Sequence"
showing 10 items of 1146 documents
An MLSA approach for the taxonomic update of the Splendidus clade, a lineage containing several fish and shellfish pathogenic Vibrio spp.
2016
A multilocus sequence analysis was undertaken in order to redefine the Splendidus clade of the genus Vibrio, a large group of species containing several pathogenic members that affect fish and shellfish, and are difficult to identify through both phenotypic and genotypic approaches. The study included analysis of partial sequences of recA, gyrB, mreB, rpoD and pyrH genes, as well as the 16S rRNA gene. Seventeen type strain species were included that were complemented with other reference strains and a collection of isolates tentatively identified as members of this clade, as well as a set of other Vibrio species. The clade was well defined and stable in all analyses, and was confirmed to co…
Purification of Leuconostoc mesenteroides citrate lyase and cloning and characterization of the citCDEFG gene cluster
1998
ABSTRACT A citrate lyase (EC 4.1.3.6 ) was purified 25-fold from Leuconostoc mesenteroides and was shown to contain three subunits. The first 42 amino acids of the β subunit were identified, as well as an internal peptide sequence spanning some 20 amino acids into the α subunit. Using degenerated primers from these sequences, we amplified a 1.2-kb DNA fragment by PCR from Leuconostoc mesenteroides subsp. cremoris . This fragment was used as a probe for screening a Leuconostoc genomic bank to identify the structural genes. The 2.7-kb gene cluster encoding citrate lyase of L. mesenteroides is organized in three open reading frames, citD , citE , and citF , encoding, respectively, the three ci…
Direct conjugal transfers of Ti plasmid to soil microflora
2002
The bacterial species in soil that can receive a Ti plasmid by conjugation from Agrobacterium spp. were investigated. In order to have direct access to the potential reservoir of Ti plasmid amongst soil microflora, the conjugal system consisting of a multiply auxotrophic derivative of C58 (ST-96-4) and a derivative of pTiC58Delta(acc)R (pSTiEGK) containing a triple antibiotic-resistance cassette in traM was used to transfer the Ti plasmid in a complex soil microflora used as the recipient. Numerous transconjugants were obtained by this method but none was identified as Agrobacterium. This could be explained by the low density of Agrobacterium in the tested soil. As indicated by analysis of …
Gene Cloning, Transcriptional Analysis, Purification, and Characterization of Phenolic Acid Decarboxylase from Bacillus subtilis
1998
Phenolic acids, also called substituted cinnamic acids, are important lignin-related aromatic acids and natural constituents of plant cell walls. These acids (particularly ferulic, p-coumaric, and caffeic acids) bind the complex lignin polymer to the hemicellulose and cellulose in plants (1) or are generally esterified with tartaric acid (for example, in grape must, wine, and cider) and can be released as free acids during wine making by some cinnamoyl esterase activities (9). Most often, free phenolic acids are metabolized by different microorganisms into 4-vinyl derivatives and then are eventually reduced into 4-ethyl derivatives (5, 6). Some of these volatile phenols, particularly vinyl …
Mutational Events in Cefotaximase Extended-Spectrum β-Lactamases of the CTX-M-1 Cluster Involved in Ceftazidime Resistance
2008
ABSTRACT CTX-M β-lactamases, which show a high cefotaxime hydrolytic activity, constitute the most prevalent extended-spectrum β-lactamase (ESBL) type found among clinical isolates. The recent explosive diversification of CTX-M enzymes seems to have taken place due to the appearance of more efficient enzymes which are capable of hydrolyzing both cefotaxime and ceftazidime, especially among the CTX-M-1 cluster. A combined strategy of in vitro stepwise evolution experiments using bla CTX-M-1 , bla CTX-M-3 , and bla CTX-M-10 genes and site-directed mutagenesis has been used to evaluate the role of ceftazidime and other β-lactam antibiotics in triggering the diversity found among enzymes belong…
Manganese/polymetallic nodules: Micro-structural characterization of exolithobiontic- and endolithobiontic microbial biofilms by scanning electron mi…
2009
Polymetallic/ferromanganese nodules (Mn-nodules) provide a rich source for manganese. It is not yet known if the nodules have a biogenic or an abiogenic origin. Here we applied the technique of high-resolution scanning electron microscopy, in combination with energy dispersive X-ray spectroscopical (EDX) analysis, to trace the existence of microbial biofilms. Two spatially separated assemblies exist, the exolithobiontic- and endolithobiontic colonizations. The exolithobiontic colonization is seen in the micro-canals, which traverse the outer surface layer of the nodules and are formed by elongated filamentous organisms, which show no signs of mineralization. In the center of the nodules thr…
Cloning, deletion, and characterization of PadR, the transcriptional repressor of the phenolic acid decarboxylase-encoding padA gene of Lactobacillus…
2004
ABSTRACTLactobacillus plantarumdisplays a substrate-induciblepadAgene encoding a phenolic acid decarboxylase enzyme (PadA) that is considered a specific chemical stress response to the inducing substrate. The putative regulator ofpadAwas located in thepadAlocus based on its 52% identity with PadR, thepadAgene transcriptional regulator ofPediococcus pentosaceus(L. Barthelmebs, B. Lecomte, C. Diviès, and J.-F. Cavin, J. Bacteriol.182:6724-6731, 2000). Deletion of theL. plantarum padRgene clearly demonstrates that the protein it encodes is the transcriptional repressor of divergently orientedpadA. ThepadRgene is cotranscribed with a downstream open reading frame (ORF1), the product of which m…
Efficient Control of raf Gene Expression by CAP and Two Raf Repressors that Bend DNA in Opposite Directions
1999
The plasmid-borne raf operon of Escherichia coli encodes proteins involved in the uptake and utilisation of the trisaccharide raffinose. The operon is subject to dual regulation; to negative control by the binding of RafR repressor to twin operators, O1 and O2, and to positive control by the cAMP-binding protein, CAP. We have identified the CAP binding site (CBS) as a 22 bp palindromic sequence with incomplete dyad symmetry by deletion analysis, DNasel footprinting and electrophoretic mobility shift assays (EMSA) of CAP-DNA complexes. The CBS is centred 60.5 bp upstream of the transcription start point and partially overlaps O1. In vivo, CAP increases rafA (alpha-galactosidase) gene express…
Oxygen-Controlled Bacterial Growth in the Sponge Suberites domuncula: toward a Molecular Understanding of the Symbiotic Relationships between Sponge …
2004
ABSTRACT Sponges (phylum Porifera), known to be the richest producers among the metazoans of bioactive secondary metabolites, are assumed to live in a symbiotic relationship with microorganisms, especially bacteria. Until now, the molecular basis of the mutual symbiosis, the exchange of metabolites for the benefit of the other partner, has not been understood. We show with the demosponge Suberites domuncula as a model that the sponge expresses under optimal aeration conditions the enzyme tyrosinase, which synthesizes diphenols from monophenolic compounds. The cDNA isolated was used as a probe to determine the steady-state level of gene expression. The gene expression level parallels the lev…
Enterococcus asini sp. nov. isolated from the caecum of donkeys (Equus asinus)
1998
Several Gram-positive, non-spore-forming and non-motile bacteria consisting of pairs or chains of cocci were isolated during an investigation of the bacterial flora of the caecum of donkeys. Physiological and metabolic data indicated that the strains belong to the genus Enterococcus; phenotypic traits of these organisms were not consistent with any of the currently known Enterococcus species. 16S rRNA gene sequence analysis placed these strains in the genus Enterococcus. Their closest relatives are Enterococcus avium, Enterococcus faecium and Enterococcus pseudoavium with a sequence similarity of 97.4%. This group of strains can be differentiated from the other Enterococcus spp. by their ph…