The activity of uridine-diphosphoglucuronosyl transferase 1 (UGT1) may influence the concentration of serum bilirubin. Because UGT1 is too labile to be measured with classical biochemical methods, we analysed the whole UGT1A1 gene in 290 healthy Taiwanese adults by using the polymerase chain reaction method, and investigated the relationship between UGT1A1 genotypes and serum bilirubin levels. The results showed that slightly more than 50% of the subjects had one or more variant sites in UGT1A1 gene. The most common variant was A(TA)6TAA/A(TA)7TAA (6/7) in the promoter area, followed by heterozygous variation within the coding region, compound heterozygous and homozygous variations. Among the four variant sites within the coding region, 211 G to A was the predominate one, 1091 C to T was a novel variation, and 686 C to A was associated with 6/7. Subjects with 6/7 or heterozygous variation within the coding region or compound heterozygous (plus one homozygous) variation had significantly higher bilirubin levels than those with wild UGT1A1 gene. When the 290 subjects were stratified into six groups according to their serum bilirubin concentrations, the bilirubin levels were correlated well to the frequencies of variant UGT1A1 gene. Our results show that there is a strong association between UGT1A1 gene and bilirubin levels in healthy Taiwanese adults. The occurrence of A(TA)7TAA allele was relatively rare and the variation rate within the coding region was much higher in Taiwanese compared to that in Caucasians.
Vibrio parahaemolyticus is a common marine food-borne enteropathogen. In this study, we examined the antioxidative activity, growth, biofilm formation, and cell mobility of an oxyR deletion mutant and its genetically complementary strain of V. parahaemolyticus. oxyR is the regulator of catalase and ahpC genes. Protection against extrinsic H 2 O 2 and against the organic peroxides cumene hydroperoxide and tert-butyl hydroperoxide was weaker in the deletion mutant than in its parent strain. Expression of the major functional antioxidative genes, ahpC1 and VPA1418, was markedly decreased in the oxyR mutant. Growth of this mutant on agar medium was significantly inhibited by autoclaved 0.25% glucose and by 0.25% dipotassium hydrogen phosphate, 0.5% monosaccharides (glucose, galactose, xylose, and arabinose), or 114.8 mM phosphates. The inhibition of the growth of this oxyR mutant by extrinsic peroxides, autoclaved sugars, and phosphates was eliminated by the complementary oxyR gene or by the addition of catalase to the autoclaved medium, while no inhibition of growth was observed when filter-sterilized sugars were used. The formation of biofilm and swimming mobility were significantly inhibited in the oxyR mutant relative to that in the wild-type strain. This investigation demonstrates the antioxidative function of oxyR in V. parahaemolyticus and its possible roles in biofilm formation, cell mobility, and the protection of growth in heated rich medium. Vibrio parahaemolyticus is a halophilic Gram-negative bacterium that is commonly associated with food-borne gastroenteritis (1), and it has exhibited global significance since the occurrence of pandemic O3:K6 strains in 1996 (2).The incomplete reduction of oxygen during aerobic metabolism or by exposure to metals, redox-active chemicals, or some environmental stresses produces various reactive oxygen species (ROS) in bacteria (3-5). ROS can damage all cellular components, including protein, DNA, and membrane lipids (6, 7). Therefore, antioxidative activity is required by pathogenic bacteria for their successful growth and survival under environmental stresses and is sometimes associated with their virulence (8), whereas characteristic antioxidative functions have been demonstrated in V. parahaemolyticus (9, 10).Several common antioxidative factors are used to scavenge ROS, including superoxide dismutases (SOD), catalases, and alkyl hydroperoxide reductase subunit C's (AhpC) (11). The expressions of catalase and ahpC genes are usually regulated by OxyR (12), which is a redox-sensitive transcriptional regulator of the LysR family in Escherichia coli, Salmonella spp., and other bacteria (13-17). OxyR also participates in pathogenesis by promoting biofilm formation, fimbrial expression, and mucosal colonization in pathogenic bacteria (18); nevertheless, the mechanism of oxidative stress defense in these phenomena is not clear (19).The function of oxyR has been examined in a few Vibrio species but not in V. parahaemolyticus. The effect of oxyR on the survival of bacteria a...
Although studies on skin microbiome of acute and chronic wounds abound, evidence on newly built microbial communities of subacute wounds remains scant. To characterize the skin microbiome of recently healed (scarred) burn wounds in relation to unaffected skin surfaces, we collected weekly swabs from patients with moderate to severe burns in the 3rd postburn month for 4 weeks in 2015. We performed skin type (moist, dry, and oily)-matched comparisons within six burn patients (43 pairs of swabs) and with 13 skin-healthy, control patients (22 pairs of samples) using 16S ribosomal RNA gene sequencing results. Results of comparative microbiome analysis showed that, there were no substantial variations in the microbial abundance (all p > 0.05) or composition (all p > 0.01, adjusted for multiple comparisons) between samples obtained from wound scars and those from unaffected surfaces of burn patients. Nor did we find significant temporal dynamics in microbial richness or diversity in burn samples (all p ≥ 0.05). However, samples from burn patients harbored more Firmicutes (median: 25.6%, interquartile range [IQR]: 14.3%-52.8%) than those of control patients (14.9%, IQR: 6.7%-27.0%; p: 0.016), even after adjusting for host age, sex, and skin type-matching (p: 0.026). The number of observed bacterial operational taxonomic units at the genus level was reduced in burn patients (median: 62, IRQ: 32-85) as compared to control patients (median: 128, IQR: 112-136; age-, skin type-adjusted p < 0.01). Meanwhile, estimates of community diversity and evenness for surveyed body sites of burn patients were higher than those of control patients (all adjusted p ≤ 0.05). With a much-reduced bacterial burden and a relative overgrowth of Staphylococcus spp., the skin microbiota of burn patients remained dysbiotic in the subacute phase as compared to that of skin-normal patients.
The marine foodborne enteropathogen, Vibrio parahaemolyticus, has four putative catalase genes. Function of the katG-homologous genes, katG1(VPA0768) and katG2(VPA0453), was examined using gene deletion mutants, and compared with those of the katE-homologous genes, katE1(VPA1418) and katE2(VPA0305). Bacterial growth of ΔkatG1 was significantly delayed in the presence of 200-300 μM H2O2, and such inhibition was enhanced when incubation temperature was lowered from 37°C to 22°C. In the stationary phase, the ΔkatG1 strain was more susceptible to the lethal dosage of H2O2 than the ΔkatE1 strain. The minimum inhibitory concentrations and minimum bactericidal concentrations revealed that ΔkatE1/ΔkatE2 strains were more susceptible to H2O2 than the ΔkatG1/ΔkatG2 strains in exponential phase, while ΔkatG1 was more susceptible than the ΔkatE1/ΔkatE2 strains in the starved culture. This study demonstrated the chief antioxidative role of katG1 in the stationary phase and starved culture of V. parahaemolyticus, while katG1 and katG2 were also responsive to H2O2 and cumene hydroperoxide in the exponential phase.
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