Phosphorylation residue T175 in RsbR protein is required for efficient induction of sigma B factor and survival of Listeria monocytogenes under acidic stress / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Listeria monocytogenes is an important zoonotic foodborne pathogen that can tolerate a number of environmental stresses. RsbR, an upstream regulator of the sigma B (SigB) factor, is thought to sense environmental challenges and trigger the SigB pathway. In Bacillus subtilis, two phosphorylation sites in RsbR are involved in activating the SigB pathway and a feedback mechanism, respectively. In this study, the role of RsbR in L. monocytogenes under mild and severe stresses was investigated. Strains with genetic deletion (ΔrsbR), complementation (C-ΔrsbR), and phosphorylation site mutations in the rsbR (RsbR-T175A, RsbR-T209A, and RsbR-T175A-T209A) were constructed to evaluate the roles of these RsbR sequences in listerial growth and survival. SigB was examined at the transcriptional and translational levels. Deletion of rsbR reduced listerial growxth and survival in response to acidic stress. Substitution of the phosphorylation residue RsbR-T175A disabled RsbR complementation, while RsbR-T209A significantly upregulated SigB expression and listerial survival. Our results provide clear evidence that two phosphorylation sites of RsbR are functional in L. monocytogenes under acidic conditions, similar to the situation in B. subtilis.

Age-dependent dichotomous effect of superoxide dismutase Ala16Val polymorphism on oxidized LDL levels

We investigated the association between superoxide dismutase (SOD) Ala16Val polymorphism and the levels of oxidized LDL lipoprotein-C (ox-LDL-C) in two age-different Greek cohorts. Four hundred fifteen middle-aged (n=147 females: 43.2+/-13 years, n=268 males: 43.3+/-14 years) Caucasian Greek subjects consisted the middle aged cohort. One hundred seventy five elderly (n=88 females: 79.9+/-4 years; n=87 males: 80.6+/-4 years) were selected from the elderly cohort. Genotype data were obtained for all of them. Multiple linear regression analysis, stratified by gender and adjusted for age, smoking habits and body mass index as covariates, showed higher ox-LDL-C levels for the middle aged men with the Val/Val genotype, compared to the other allele (Ala/Ala and Ala/Val) carriers (65.9+/-25.7 vs. 55.7+/-20.5 mg/dl; standardized beta coefficient=0.192, P=0.012). On the contrary, elderly women with the Val/Val genotype occurred with lower ox-LDL-C levels compared to the Ala/Ala or Ala/Val genotype (74.2+/-22.1 vs. 86.5+/-26.6 mg/dl; standardized beta coefficient= -0.269, P=0.015). The same trend was also recorded in elderly men, however without reaching statistical significance (standardized b coefficient= -0.187, P=0.077). Moreover, elderly men and women with the Ala/Ala or Ala/Val genotype presented higher triglycerides levels compared to Val/Val (women: 145.2+/-68.7 vs. 114.3+/-34.3 mg/dl, P= 0.027; men: 147.8+/-72.4 vs. 103.7 +/-38.0 mg/dl, P=0.002). Additionally, middle aged men with the Val/Val genotype had higher HDL-C levels compared to the Ala allele carriers. The results suggest that SOD Ala16Val polymorphism is an age-dependent modulator of ox-LDL-C levels in middle-aged men and elderly women.

The association of Pro12Ala polymorphism of peroxisome proliferator-activated receptor-gamma gene with serum osteoprotegerin levels in healthy Korean women

Recent evidences suggest that the activation of peroxisome proliferator-activated receptor (PPAR)-gamma, which is an important transcriptional factor in adipocyte differentiation, also plays an important role in the bone microenvironment. The objective of the study was to clarify whether Pro12Ala polymorphism was related to the serum OPG levels and bone mineral metabolism in healthy Korean women. In 239 Korean women (mean age 51 years), who participated in medical check-up program in a health promotion center, anthropometric measurements, lumbar spine and femoral neck bone mineral density (BMD), bone turnover markers, such as serum total alkaline phosphatase (ALP) levels, urine deoxypyridinoline levels, and 24-h urine calcium excretion were measured. Serum levels of OPG were measured with ELISA method. DNAs were extracted from the samples and the genotyping of the Pro12Ala polymorphism (rs1801282) in the PPAR-gamma gene was performed via an allelic discrimination assay using a TaqMan probe. In addition, we examined the haplotype analysis between two polymorphisms of PPAR-gamma gene, Pro12Ala in exon B and C161T in exon 6 (rs3856806). Allelic frequencies were 0.950 for Pro allele and 0.050 for Ala allele, which was in compliance with Hardy- Weinberg equilibrium, and there was no Ala12Ala genotype among the genotyped subjects. Mean serum OPG level was significantly lower (P=0.035), and serum total ALP was significantly higher (P=0.014) in the Pro12Ala genotype group compared with the Pro12Pro genotype group, which were consistently significant even after adjustment for weight, height, and serum follicle stimulating hormone (FSH). In multiple regression analysis with serum OPG as the dependent variable and age, weight, ALP, femoral neck BMD and Pro12Ala genotype included in the model, only Pro12Ala genotype was significant determinant of serum OPG level (beta=-0.136, P=0.035). The haplotype analysis with C161T polymorphism revealed that subjects with Ala and T alleles showed significantly lower serum OPG levels compared with those with Pro12Pro/CC genotype, which were consistently significant even after adjustment for age, weight, height and FSH (P=0.010). This result suggests statistically significant association of Pro12Ala polymorphisms with serum OPG levels in Korean females.

The influence of the Pro12Ala mutation of PPARgamma2 receptor gene on beta-cells restoration and insulin resistance in type 2 diabetes with hypertension / 华中科技大学学报（医学）（英德文版）

The aim of this investigation was to determine whether a PPARgamma2 Pro12Ala polymorphism was associated with insulin resistance, beta-cell function and hypertension in Chinese populations. 289 unrelated Chinese subjects first diagnosed Type 2 diabetes (HbAC1 < 6.0) were investigated, including 132 hypertensive diabetic (HTD) subjects, 157 normotensive diabetic (NTD) subjects. Blood pressure and anthropometric measurements were collected from all participants, as well as several venous blood samples during oral glucose tolerance test (OGTT). Biochemical measurements (high-density lipoprotein (HDL) and low-density lipoprotein-cholesterol (LDL), triglycerides) and PPARgamma2 Pro12Ala genotype were also determined. And insulin resistance and beta-cells function was assessed by HOMA-IR and HOMA-beta respectively. The frequency of subjects bearing the Pro12Ala was lower in the hypertension group (3.03%) than in the non-hypertension group (5.7%) (P < 0.05) after adjusted for age, BMI and gender. Hypertensive diabetic Pro12Ala subjects had lower fasting plasma glucose level (P = 0.0127), and better glucose tolerance 60 min after oral glucose (P = 0.0361). Moreover, plasma insulin concentrations at 60 min was lower than those without A variant (P = 0.0275), and both hypertensive Ala/Pro in HOMA-beta (P = 0.0455) and AUC for insulin (P = 0.0473) were higher, and HOMA-IR was lower (P = 0.0375) as compared with hypertensive Pro/Pro subjects. No association was observed between Pro12Ala genotype and BMI, total cholesterol, HDL- cholesterol or triglycerides in either group. Our findings suggested that the Ala 12 allele of the PPARgamma2 gene may improve insulin resistance and ameliorate beta-cell function reserves in T2DM with hypertension, and protect patients from hypertension in T2DM. As an important thrifty gene, environment factors may exerts an effect of PPAR gamma2 on glucose homeostasis and insulin resistance.

Hb G Makassar (beta 6:Glu-Ala) in a Thai family.

Hemoglobin G Makassar was identified in a family of Thai origin, which was found to share identical properties with hemoglobin S in routine hemoglobin separation both by cellulose acetate electrophoresis and cation-exchange HPLC. It is, therefore, subjects with hemoglobin G Makassar and hemoglobin S who may sometimes be mistakenly identified for each other. In this study, identification of hemoglobin G Makassar was achieved by DNA sequence analysis, which revealed a single nucleotide substitution GAG-->GCG at codon 6 of the beta-globin gene. The hemoglobin variant was hemoglobin G Makassar [beta 6:Glu-->Ala]. This is the first report of hemoglobin G Makassar in Thailand.

von Willebrand disease with G4022A mutation (vWd Sungnam): a case report

A 10-year-old male patient affected by type 2 von Willebrand disease (vWD) and his family members were investigated by hemostatic and molecular genetic studies. The propositus, who experienced frequent bleeding episodes, was characterized by a normal level of von Willebrand factor (vWF) antigen (54%), reduced vWF ristocetin cofactor activity (5%), decreased factor VIII clotting activity (25%) and absent high molecular weight multimers in the plasma. An exon 28 fragment coding for the A1 and A2 domains was amplified by polymerase chain reaction and sequenced. We found a heterozygous mutation (G4022A), producing an additional PstI restriction site, which resulted in the substitution of Arg578Gln. Family studies, including the parents and a brother, were negative for this mutation and vWF abnormalities were not observed. We confirmed that G to A mutation in the region of the platelet glycoprotein Ib binding domain of vWF causes the qualitative type 2 defect in von Willebrand disease.