Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.13.3 (histidine kinase)
 2,405 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tannerella forsythia is a Gram-negative oral anaerobe closely associated with both periodontal and periapical diseases. The ORF TF0022 of strain ATCC 43037 encodes a hybrid two-component system consisting of an N-terminal histidine kinase and a C-terminal response regulator. Disruption of the TF0022 locus enhanced autoaggregation of the broth-cultured cells. Comparative proteome analyses revealed that two S-layer proteins in the TF0022 mutant exhibited decreased apparent masses by denaturing gel electrophoresis, suggesting a deficiency in post-translational modification. Furthermore, the mutant decreased the production of a glycosyltransferase encoded by TF1061 that is located in a putative glycosylation-related gene cluster. Quantitative real-time PCR revealed reduced transcription of TF1061 and the associated genes in the TF0022 mutant. These results indicate that TF0022 upregulates the expression of the glycosylation-related genes and suggest modulation of the autoaggregation of T. forsythia cells by a possible post-translational modification of cell-surface components.
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PMID:A hybrid two-component system of Tannerella forsythia affects autoaggregation and post-translational modification of surface proteins. 2138 2

The emergence of multidrug-resistant (MDR) Klebsiella pneumoniae has resulted in a more frequent reliance on treatment using colistin. However, resistance to colistin (Col(r)) is increasingly reported from clinical settings. The genetic mechanisms that lead to Col(r) in K. pneumoniae are not fully characterized. Using a combination of genome sequencing and transcriptional profiling by RNA sequencing (RNA-Seq) analysis, distinct genetic mechanisms were found among nine Col(r) clinical isolates. Col(r) was related to mutations in three different genes in K. pneumoniae strains, with distinct impacts on gene expression. Upregulation of the pmrH operon encoding 4-amino-4-deoxy-L-arabinose (Ara4N) modification of lipid A was found in all Col(r) strains. Alteration of the mgrB gene was observed in six strains. One strain had a mutation in phoQ. Common among these seven strains was elevated expression of phoPQ and unaltered expression of pmrCAB, which is involved in phosphoethanolamine addition to lipopolysaccharide (LPS). In two strains, separate mutations were found in a previously uncharacterized histidine kinase gene that is part of a two-component regulatory system (TCRS) now designated crrAB. In these strains, expression of pmrCAB, crrAB, and an adjacent glycosyltransferase gene, but not that of phoPQ, was elevated. Complementation with the wild-type allele restored colistin susceptibility in both strains. The crrAB genes are present in most K. pneumoniae genomes, but not in Escherichia coli. Additional upregulated genes in all strains include those involved in cation transport and maintenance of membrane integrity. Because the crrAB genes are present in only some strains, Col(r) mechanisms may be dependent on the genetic background.
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PMID:Genomic and transcriptomic analyses of colistin-resistant clinical isolates of Klebsiella pneumoniae reveal multiple pathways of resistance. 2538 17