Isolation and characterization of a transposon mutant of Pseudomonas aeruginosa affecting uptake of dibenzothiophene in n-tetradecane
LETTERS IN APPLIED MICROBIOLOGY
Authors: Noda, K; Watanabe, K; Maruhashi, K
Abstract
Aims: Isolation and characterization of a transposon mutant of Pseudomonas aeruginosa affecting the uptake of dibenzothiophene (DBT) in n-tetradecane (n-TD). Methods and Results: The dsz desulphurization gene cluster from Rhodococcus erythropolis KA2-5-1 was transferred to the chromosome of P. aeruginosa NCIMB9571 using a transposon vector. A recombinant (named PARM1) was obtained which was able to desulphurize DBT in water, but not in n-TD. Conclusions: PARM1 is a mutant deficient in a DBT transport system operational in n-TD. This transport system is independent of rhamnolipids and of the n -alkane transport system. Significance and Impact of the Study: Pseudomonas aeruginosa NCIMB9571 seems to have a specific system of transporting hydrophobic compounds such as DBT in oil.
Genetic susceptibility to inflammation and colonic transit in lower functional gastrointestinal disorders: preliminary analysis
NEUROGASTROENTEROLOGY AND MOTILITY
Authors: Camilleri, M.; Carlson, P.; McKinzie, S.; Zucchelli, M.; D'Amato, M.; Busciglio, I.; Burton, D.; Zinsmeister, A. R.
Abstract
Background Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) coexist in some patients. We observed an association between Crohn's disease (CD) candidate gene TNFSF15 and IBS symptom phenotype. Three genes (TLR9, IL6, and CDH1) have been associated with postinfectious (PI)-IBS. Our aim was to preliminarily assess association between 30 susceptibility loci for CD, three genes associated with PI-IBS, and PARM1, with colonic transit in lower functional gastrointestinal disorders (FGID). Methods A cohort of 665 persons was assembled in previous studies. TaqMan assay was used for all single nucleotide polymorphisms (SNPs) associated with the loci of interest. Data were analyzed for univariate associations with symptoms phenotype and colonic transit (nominal P values, uncorrected) using dominant and co-dominant genetic models. Key Results Carriers of the rs5743836 risk allele had increased odds for IBS-D (vs control, P = 0.02, uncorrected). Among the CD risk loci, rs7927894 (P = 0.007), rs7746082 (P = 0.011), rs2872507 (P = 0.014), together with rs5743836 (P = 0.010) were univariately associated with colonic transit at 24 or 48 h. Specific tests for genetic interactions between loci revealed potential association of genes that influence neural, barrier, or mast cell function with colonic transit. Conclusions & Inferences Genetic variations that may influence local mucosal immune functions are univariately associated with altered colonic transit in lower FGID.