16S-23S rDNA间隔序列PCR与RFLP对分支杆菌临床分离株的鉴定价值

为阐明分支杆菌同种临床分离株不同菌株之间以及与标准株之间１６Ｓ－２３ＳｒＤＮＡ间隔序列是否有差异，以及结核分支杆菌耐药性和１６Ｓ－２３ＳｒＤＮＡ间隔序列有无关系。本文对５８株结核分支杆菌临床分离株（２０株敏感株，３８株耐药株）和淡黄、副偶然、母牛等分支杆菌的临床分离株的１６Ｓ－２３ＳｒＤＮＡ间隔序列进行了扩增，并对扩增产物进行了聚丙烯酰胺凝胶电和琼脂糖凝胶电泳及限制性内切酶ＨａｅⅢ、ＭａｐⅠ消化反应。同种分支杆菌各菌株之间扩增产物及限制性内切酶消化产物均无差异。不同种各株之间均不相同。结果说明同种分支杆菌不同临床分离株１６Ｓ－２３ＳｒＤＮＡ间隔序列没有差异，结核分支杆菌１６Ｓ－２３ＳｒＤＮＡ间隔序列与菌株耐药性没有关系。１６Ｓ－２３ＳｒＤＮＡ间隔序列ＰＣＲ扩增与ＲＦＬＰ分析对分支杆菌临床分离株的鉴定有价值。

Bioleaching of Pb-Zn-Sn chalcopyrite concentrate in tank bioreactor and microbial community succession analysis

The variation of microbial community structure was investigated for the tank bioleaching process of Pb-Zn-Sn chalcopyrite concentrate in the presence of mixed moderately thermophilic bacteria. The parameters, such as pH value, solution potential and concentrations of metal ions, were determined by the method of polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） to analyze the succession of microbial community. The results showed that a final copper extraction rate of 85.6% could be obtained after tank bioleaching for 30 d. The Acidithiobacillus caldus was the dominant population with abundance of about 73.80%in the initial stage, then Sulfobacillus thermosulfidooxidans dominated from the 18th day to the end of bioleaching, while the abundance of Leptospirillum ferriphilum changed slightly. A higher solution potential within a certain range and appropriate concentration of ferric ions were essential for this tank bioleaching of chalcopyrite.

Studies on the relationship between the point mutation of ras oncogenes and the prognosis of patients with gastric cancer

AIM To study the relationship between the point mutation of ras oncogenes and the prognosis of patients with gastric cancer.

UGT1A1 predicts outcome in colorectal cancer treated with irinotecan and fluorouracil

AIM:To evaluate effects of UDP-glucuronosyltransferase1A1(UGT1A1) and thymidylate synthetase(TS) gene polymorphisms on irinotecan in metastatic colorectal cancer(mCRC).METHODS:Two irinotecan-and fluorouracil-based regimens,FOLFIRI and IFL,were selected as second-line therapy for 138 Chinese mCRC patients.Genomic DNA was extracted from peripheral blood samples before treatment.UGT1A1 and TS gene polymorphisms were determined by direct sequencing and restriction fragment length polymorphism,respectively.Gene polymorphisms of UGT1A1*28,UGT1A1*6 and promoter enhancer region of TS were analyzed.The relationship between genetic polymorphisms and clinical outcome,that is,response,toxicity and survival were assessed.Pharmacokinetic analyses were performed in a subgroup patients based on different UGT1A1 genotypes.Plasma concentration of irinotecan and its active metabolite SN-38 and inactive metabolite SN-38G were determined by high performance liquid chromatography.Differences in irinotecan and its metabolites between UGT1A1 gene variants were compared.RESULTS:One hundred and eight patients received the FOLFIRI regimen,29 the IFL regimen,and one irinotecan monotherapy.One hundred and thirty patients were eligible for toxicity and 111 for efficacy evaluation.One hundred and thirty-six patients were tested for UGT1A1*28 and *6 genotypes and 125 for promoter enhancer region of TS.Patients showed a higher frequency of wild-type UGT1A1*28(TA6/6) compared with a Caucasian population(69.9% vs 45.2%).No significant difference was found between response rates and UGT1A1 genotype,although wild-type showed lower response rates compared with other variants(17.9% vs 24.2% for UGT1A1*28,15.7% vs 26.8% for UGT1A1*6).When TS was considered,the subgroup with homozygous UGT1A1*28(TA7/7) and non-3RG genotypes showed the highest response rate(33.3%),while wild-type UGT1A1*28(TA6/6) with non-3RG only had a 13.6% response rate,but no significant difference was found.Logistic regression showed treatment duration was closely linked to clinical response.In toxicity comparison,UGT1A1*28 TA6/6 was associated with lower incidence of grade 2-4 diarrhea(27.8% vs 100%),and significantly reduced the risk of grade 4 neutropenia compared with TA7/7(7.8% vs 37.5%).Wild-type UGT1A1*6(G/G) tended to have a lower incidence of grade 3/4 diarrhea vs homozygous mutant(A/A) genotype(13.0% vs 40.0%).Taking UGT1A1 and TS genotypes together,lower incidence of grade 2-4 diarrhea was found in patients with non-3RG TS genotypes,when TA6/6 was compared with TA7/7(35.3% vs 100.0%).No significant association with time to progression(TTP) and overall survival(OS) was observed with either UGT1A1 or TS gene polymorphisms,although slightly longer TTP and OS were found with UGT1A1*28(TA6/6).Irinotecan PK was investigated in 34 patients,which showed high area under concentration curve(AUC) of irinotecan and SN-38,but low AUC ratio(SN-38G /SN-38) in those patients with UGT1A1*28 TA7/7.CONCLUSION:A distinct distribution pattern of UGT1A1 genotypes in Chinese patients might contribute to relatively low toxicity associated with irinotecan and 5-fluorouracil in mCRC patients.

Risk factors and gene polymorphisms of inflammatory bowel disease in population of Zhejiang,China

AIM:To identify the risk factors and three single nucleotide polymorphisms(SNPs) of NOD2/CARD15 gene in inflammatory bowel disease(IBD) of the population in Zhejiang,China.METHODS:A case-control study was conducted using recall questionnaire to collect data on demographic,socioeconomic,lifestyle characteristics and dietary behaviors from 136 determined IBD patients and 136 paired healthy controls.COX regression method was used to screen the statistically significant risk factors for IBD.The polymorphisms of NOD2/CARD15 gene Arg702Trp,Gly908Arg and Leu1007fsinsC were genotyped and further compared between 60 patients with IBD and 60 healthy controls by polymerase chain reaction and restriction fragment length polymorphism.RESULTS:IBD occurred primarily in young and middle-aged people.The mean age for IBD patients was 42.6 years.The ratio of males to females was 1.23:1.COX regression indicated a higher statistical significance in milk,fried food and stress compared with the other postulated risk factors for IBD.None of the patients with IBD and healthy controls had heterozygous or homozygous SNPs variants.CONCLUSION:Milk,fried food and stress are associated with increased risk of IBD.The common variants in NOD2/CARD15 gene are not associated with IBD in China's Zhejiang population.

Epiphytic bacterial communities on two common submerged macrophytes in Taihu Lake: diversity and host-specificity

Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species. However, the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood. We investigated the diversity and composition of epiphytic bacteria from two common submerged macrophytes: Vallisneria natans and Hydrilla verticillata in Taihu Lake, Jiangsu, China, using methods of terminal restriction fragment length polymorphisms (T-RFLP) and clone library analyses targeted at bacterial 16S rRNA genes. The results show that: (1) the libraries of the two waterweeds contain wide phylogenetic distribution of bacteria, and that the sequences of the two libraries can be separated into 93 OTUs (at 97% similar value); (2) Betaproteobacteria, including Burkholderiales, was the most abundant bacterial group on both plants. Cyanobacteria and Gammaproteobacteria were the second largest groups on V. natans and H. verticillata, respectively. Both clone libraries included some sequences related to those of methanotrophs and nitrogen-fixing bacteria; (3) Cluster analysis of the T-RFLP profiles showed two distinct clusters corresponding to the two plant populations. Both ANOSIM of the T-RFLP data and Libshuff analysis of the two clone libraries indicated a significant difference in epiphytic bacterial communities between the two plants. Therefore, the epiphytic bacterial communities on submerged macrophytes appear to be diverse and host-specific, which may aid in understanding the ecological functions of submerged macrophytes in general.

Immunohistochemical evaluation of vitamin D receptor(VDR) expression in cutaneous melanoma tissues and four VDR gene polymorphisms

Objective:Vitamin D receptor(VDR)mediates vitamin D activity.We examined whether VDR expression in excised melanoma tissues is associated with VDR gene(VDR)polymorphisms.Methods:We evaluated VDR protein expression(by monoclonal antibody immunostaining),melanoma characteristics,and carriage of VDR-Fok I-rs2228570(C>T),VDR-Bsm I-rs1544410(G>A),VDR-ApaI-rs7975232(T>G),and VDR-TaqI-rs731236(T>C)polymorphisms(by restriction fragment length polymorphism).Absence or presence of restriction site was denoted by a capital or lower letter,respectively:"F"and"f"for Fok I,"B"and"b"for Bsm I,"A"and"a"for ApaI,and "T"and"t"for TaqI endonuclease.Seventy-four Italian cutaneous primary melanomas(52.1±12.7 years old)were studied;51.4% were stage Ⅰ,21.6% stage Ⅱ ,13.5% stage Ⅲ,and 13.5% stage Ⅳ melanomas.VDR expression was categorized as follows:100% positive vs.<100%;over the median 20%(high VDR expression)vs.≤20%(low VDR expression);absence vs.presence of VDR-expressing cells.Results:Stage I melanomas,Breslow thickness of<1.00 mm,level II Clark invasion,Aa heterozygous genotype,and AaTT combined genotype were more frequent in melanomas with high vs.low VDR expression.Combined genotypes BbAA,bbAa,AATt,BbAATt,and bbAaTT were more frequent in 100%vs.<100%VDR-expressing cells.Combined genotype AATT was more frequent in melanomas lacking VDR expression(odds ratio=14.5;P=0.025).VDR expression was not associated with metastasis,ulceration,mitosis>1,regression,tumor-infiltrating lymphocytes,tumoral infiltration of vascular tissues,additional skin and non-skin cancers,and melanoma familiarity.Conclusions:We highlighted that VDR polymorphisms can affect VDR expression in excised melanoma cells.Low VDR expression in AATT carriers is a new finding that merits further study.VDR expression possibly poses implications for vitamin D supplementation against melanoma.VDR expression and VDR genotype may become precise medicinal tools for melanoma in the future.

Association between MDM2-SNP309 and hepatocellular carcinoma in Taiwan Residents population

AIM:To investigate the risk association and compare the onset age of hepatocellular carcinoma(HCC) patients in Taiwan with different genotypes of MDM2- SNP309. METHODS:We analyzed MDM2-SNP309 genotypes from 58 patients with HCC and 138 cancer-free healthy controls consecutively.Genotyping of MDM2-SNP309 was conducted by restriction fragment length polymor- phism assay. RESULTS:The proportion of homozygous MDM2- SNP309 genotype(G/G)in cases and cancer-free healthy controls was similar(17.2%vs 16.7%).Multi-variate analysis showed that the risk of G/G genotypeof MDM2-SNP309 vs wild-type T/T genotype in patients with HCC was not significant(OR=1.265,95% CI=0.074-21.77)after adjustment for sex,hepatitis B or C virus infection,age,and cardiovascular disease/ diabetes.Nevertheless,there was a trend that GG genotype of MDM2-SNP309 might increase the risk in HCC patients infected with hepatitis virus(OR=2.568, 95%CI=0.054-121.69).Besides,the homozygous MDM2-SNP309 genotype did not exhibit a significantly earlier age of onset for HCC. CONCLUSION:Current data suggest that the asso- ciation between MDM2-SNP309 GG genotype and HCC is not significant,while the risk may be enhanced in patients infected by hepatitis virus in Taiwan.

Association betweenITGA2 C807T polymorphism and gastric cancer risk

AIM： To evaluate the impact of the ITGA2 gene polymorphism on gastric cancer risk. METHODS： A hospital-based case-control study was conducted, including 307 gastric cancer patients and 307 age- and gender-matched control subjects. The genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism assay. RESULTS： The frequencies of the wild and variant genotypes in cases were significantly different from those of controls （P = 0.019）. Compared with individuals with the wild genotype CC, subjects with the variant genotypes （CT ＋ IT） had a significantly higher risk of gastric cancer （adjusted odds ratio = 1.57, 95% CI = 1.13-2.17, P = 0.007）. In stratified analyses, the elevated gastric cancer risk was especially evident in older individuals aged 〉 58 years, nonsmokers and rural subjects. Further analyses revealed that the variant genotypes were associated with poor tumor differentiation and adjacent organ invasion in the sub-analysis of gastric cancer patients. CONCLUSION： The ITGA2 gene C807T polymorphism may be associated with an increased risk of gastric cancer, differentiation and invasion of gastric cancer.

Gut bacteria alteration in obese people and its relationshipwith gene polymorphism

AIM:To investigate the differences in cultivable gut bacteria and peroxisome proliferator-activated receptor γ2(PPAR-γ2) gene Pro12Ala variation in obese and normal-weight Chinese people.METHODS:Using culture methods,the amounts of Escherichia coli,Enterococci,Bacteroides,Lactobacilli,Bif idobacteria and Clostridium perfringens(C.perfringens) in the feces of 52 obese participants [body mass index(BMI):≥ 28 kg/m2] and 52 participants of normalweight(BMI:18.5-24 kg/m2) were obtained.Study participants completed comprehensive questionnaires and underwent clinical laboratory tests.The polymerase chain reaction-restriction fragment length polymorphism(PCR-PFLP) assay was used to analyze PPAR-γ2 gene Pro12Ala variation.RESULTS:The obese group exhibited a lower amount of C.perfringens(6.54 ± 0.65 vs 6.94 ± 0.57,P = 0.001)and Bacteroides(9.81 ± 0.58 vs 10.06 ± 0.39,P = 0.012) than their normal-weight counterparts.No major differences were observed in Pro12Ala genotype distribution between the two groups;however,obese individuals with a Pro/Ala genotype had a signif icantly lower level of Bacteroides(9.45 ± 0.62 vs 9.93 ± 0.51,P = 0.027) than those with a Pro/Pro genotype.In addition,the obese group demonstrated a higher stool frequency(U = 975,P < 0.001) and a looser stool(U = 1062,P = 0.015) than the normal-weight group.CONCLUSION:Our results indicated interactions among cultivable gut flora,host genetic factors and obese phenotype and this might be helpful for obesity prevention.

Association between polymorphism rs6983267 and gastric cancer risk in Chinese population

AIM: To explore the association between single nucleotide polymorphisms (SNPs) at 8q24 and gastric cancer risk. METHODS: A case-control investigation including 212 gastric cancer patients and 377 healthy controls was conducted. The genotypes of SNPs (rs6983267, rs7008482 and rs10808555) were examined and established through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Multivariate logistic regression models were used to evaluate the association between SNPs and gastric cancer. RESULTS: The genotype frequencies of rs6983267 in gastric cancer patients were obviously different from those in the control (P = 0.005). GT genotype of rs6983267 was associated with an increased risk of gastric cancer compared with GG genotype (adjusted odds ratio = 2.01, 95% confidence interval: 1.28-3.14). Further stratified analysis indicated that rs6983267 GT genotype facilitated the risk of gastric cancer of non-cardiac and intestinal type (OR: 2.638, 95% CI: 1.464-4.753; OR: 1.916, 95% CI: 1.166-3.150, respectively). CONCLUSION: This study demonstrates for the first time that rs6983267 is involved in susceptibility to gastric cancer, although further large-sample investigations are still needed.

Differentiation of Sheeppox and Goatpox Viruses by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism

In the present study,the partial gene sequences of P32 protein,an immunogenic envelope protein of Capripoxviruses (CaPV),were analyzed to assess the genetic relationship among sheeppox and goatpox virus isolates,and restriction enzyme specific PCR-RFLP was developed to differentiate CaPV strains.A total of six goatpox virus (GTPV) and nine sheeppox virus (SPPV) isolates of Indian origin were included in the sequence analysis of the attachment gene.The sequence analysis revealed a high degree of sequence identity among all the Indian SPPV and GTPV isolates at both nucleotide and amino acid levels.Phylogenetic analysis showed three distinct clusters of SPPV,GTPV and Lumpy skin disease virus (LSDV) isolates.Further,multiple sequence alignment revealed a unique change at G120A in all GTPV isolates resulting in the formation of Dra I restriction site in lieu of EcoR I,which is present in SPPV isolates studied.This change was unique and exploited to develop restriction enzyme specific PCR-RFLP for detection and differentiation of SPPV and GTPV strains.The optimized PCR-RFLP was validated using a total of fourteen (n=14) cell culture isolates and twenty two (n=22) known clinical samples of CaPV.The Restriction Enzyme specific PCR-RFLP to differentiate both species will allow a rapid differential diagnosis during CaPV outbreaks particularly in mixed flocks of sheep and goats and could be an adjunct/supportive tool for complete gene or virus genome sequencing methods.

COX-2 polymorphisms-765G→C and-1195A→G and colorectal cancer risk

AIM： TO determine the possible modulating effect of the COX-2 polymorphisms, -765G→C and -1195A→G, on the risk of colorectal cancer （CRC） in a Dutch population. METHODS： This case-control study includes 326 patients with CRC and 369 age- and gender-matched controls. Genotypes of the COX-2 polymorphisms -7dEG→C and -1195A→G were determined by polymerase chain reaction-based restriction fragment length polymorphism. COX-2 genotypes and haplotypes were analyzed and odds ratios with 95% confidence intervals were estimated by logistic regression. RESULTS： The -765GG genotype was associated with an increased risk of developing CRC （OR, 1.45; 95% CI, 1.03-2.04）. No significant difference was observed in the genotype distribution of the -1195A→G polymorphism between patients and controls. The GG/AC haplotype was present significantly less often in patients than in controls （OR 0.44; 95% CI, 0.22-0.85）. When the AC, AG and GG haplotypes were investigated separately, the AC haplotype showed a tendency to be less frequent in patients than in controls （OR（AG/AC） 0.78; 95% CI, 0.57-1.06）. CONCLUSION： The -765GG genotype is associated with an increased risk of developing CRC and the G6/ AC haplotype seems to protect against CRC. These findings suggest a modulating role for the COX-2 polymorphisms -765G→C and -1195A→G in the development of CRC in a Dutch population.

Association of Fas/Apo1 gene promoter (-670 A/G) polymorphism in Tunisian patients with IBD

AIM： To detect a possible association between the polymorphism of the （-670 A/G） Fas/Apol gene promoter and susceptibility to Crohn＇s disease （CD） and ulcerative colitis （UC） in the Tunisian population. METHODS： The （-670 A/G） Fas polymorphism was analyzed in 105 patients with CD, 59 patients with UC, and 100 controls using the polymerase chain reaction restriction fragment length polymorphism method. RESULTS： Significantly lower frequencies of the Fas -670 A allele and A/A homozygous individuals were observed in CD and UC patients when compared with controls. Analysis of （-670 A/G） Fas polymorphism with respect to sex in CD and UC showed a significant difference in A/A genotypes between female patients and controls （P corrected = 0.004 ＂in CD patients＂ and P corrected = 0.02 ＂in UC patients＂, respectively）. Analysis also showed a statistically significant association between genotype AA of the （-670 A/G） polymorphism and the ileum localization of the lesions （P corrected = 0.048） and between genotype GG and the colon localization （P corrected = 0.009）. The analysis of IBD patients according to clinical behavior revealed no difference. CONCLUSION： Fas-670 polymorphism was associated with the development of CD and UC in the Tunisian population.

N-Acetyltransferase 2 genetic polymorphisms and risk of colorectal cancer

AIM:To investigate the possible association between meat intake,cigarette smoking and N-acetyltransferase 2 (NAT2) genetic polymorphisms on colorectal cancer (CRC) risk.METHODS:Patients with CRC were matched for gender and age to healthy controls.Meat intake and cigarette smoking were assessed using a specific frequency questionnaire.DNA was extracted from peripheral blood and the genotypes of the polymorphism were assessed by polymerase chain reaction-restriction fragment length polymorphism.Five NAT2 alleles were studied (WT,M1,M2,M3 and M4) using specific digestion enzymes.RESULTS:A total of 147 patients with colorectal cancer (76 women and 90 men with colon cancer) and 212 controls were studied.The mean age of the two groups was 62 years.More than half the subjects (59.8% in the case group and 51.9% in the control group) were NAT2 slow acetylators.The odds ratio for colorectal cancer was 1.38 (95% CI:0.90-2.12) in slow acetylators.Although the number of women was small (n=76 in the case group),the cancer risk was found to be lower in intermediate (W/Mx) acetylators [odds ratio (OR):0.55,95% confidence interval (95% CI):0.29-1.02].This difference was not observed in men (OR:0.56,95% CI:0.16-2.00).Among NAT2 fast acetylators (W/W or W/Mx),meat consumption more than 3 times a week increased the risk of colorectal cancer (OR:2.05,95% CI:1.01-4.16).In contrast,cigarette smoking increased the risk of CRC among slow acetylators (OR:1.97,95% CI:1.02-3.79).CONCLUSION:The risk of CRC was higher among fast acetylators who reported a higher meat intake.Slow NAT2 acetylation was associated with an increased risk of CRC.

Analysis of TLR4 and TLR2 polymorphisms in inflammatory bowel disease in a Guangxi Zhuang population

AIM: To study the polymorphisms of toll-like receptor 4 (TLR4) gene Asp299Gly, Thr399Ile and TLR2 gene Arg753Gln, Arg677Trp and susceptibility to inflammatory bowel disease (IBD) in the Zhuang population from Guangxi, China. METHODS: A case-control study was performed from February 2007 to October 2011 which included 146 Zhuang patients with IBD in the experimental group and 164 healthy Zhuang subjects who acted as the control group. All patients and healthy subjects were from the Guangxi Zhuang Autonomous Region of China. Genomic DNA was extracted from intestinal tissue by the phenol chloroform method. TLR4 gene Asp299Gly, Thr399Ile and TLR2 gene Arg753Gln, Arg677Trp were amplified by polymerase chain reaction (PCR), and then detected by PCR-restriction fragment length polymorphism (RFLP). RESULTS: The TLR4 gene Asp299Gly was digested using Nco Ⅰ restriction enzyme, and a single band of 249 bp was observed which showed that it was a wild type (AA). The TLR4 gene Thr399Ile was digested using Hinf Ⅰrestriction enzyme and only the wild type (CC) was detected. In addition, the TLR2 gene Arg-677Trp was digested using Aci Ⅰ restriction enzyme and only the wild type (CC) was detected. The TLR2 gene Arg753Gln was digested using Pst Ⅰ restriction enzyme. Only the wild type (GG) as a single band of 254 bp was observed during RFLP. Overall, no heterozygous or homozygous single nucleotide polymorphism mutations were found in patients with Crohn's disease and ulcerative colitis both in the TLR4 gene Asp299Gly, Thr399Ile and the TLR2 gene Arg677Trp, Arg753Gln in the Zhuang population from the Guangxi Zhuang Autonomous Region of China. CONCLUSION: The TLR4 gene Asp299Gly, Thr399Ile and TLR2 gene Arg753Gln, Arg677Trp polymorphisms may not be associated with IBD in the Zhuang population from the Guangxi Zhuang Autonomous Region of China.

Characterization of clarithromycin resistance in Malaysian isolates of Helicobacter pylori

AIM： To characterize the types of mutations present in the 23S rRNA genes of Malaysian isolates of clarithromycin-resistant Helicobacter pylori （H pylorl~. METHODS： Clarithromycin susceptibility of H pylori isolates was determined by E test. Analyses for point mutations in the domain V of 23S rRNA genes in clarithromycin-resistant and -sensitive strains were performed by sequence analysis of amplified polymerase chain reaction products. Restriction fragment length polymorphism was performed using Bsa I and MboI enzymes to detect restriction sites that correspond to the mutations in the clarithromycin- resistant strains. RESULTS： Of 187 isolates from 120 patients, four were resistant to clarithromycin, while 183 were sensitive. The MIC of the resistant strains ranged from 1.5 to 24 pg/mL. Two isolates had an A2142G mutation and another two had A2143G mutations. A T2182C mutation was detected in two out of four clarithromycin-resistant isolates and in 13 of 14 clarithromycin-sensitive isolates. Restriction enzyme analyses with Bsa I and Mbo I were able to detect the mutations. CONCLUSION： Clarithromycin resistance is an uncommon occurrence among Malaysian isolates of Hpylori strains and the mutations A2142G and A2143G detected were associated with low-level resistance.

Association between the Epidermal Growth Factor Gene and Intelligence in Major Depression Patients

Objective To study the association between the epidermal growth factor(EGF) gene and intelligence in patients with major depression.Methods Intelligence measurement using Wechsler Adult Intelligence Scale(WAIS) was perfor-med on 120 unrelated patients with major depression and 46 control subjects.Blood was collected from all subjects for extraction of genomic DNA.Four single nucleotide polymorphisms(SNPs) in the EGF gene were genotyped using polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Results Mean scores of both score lang and score task,two subtests in WAIS,differed significantly between major depression patients and controls(P<0.0001).Quantitative trait analysis showed that the genetype of rs2250724 was closely associated with score lang and score task in major depression patients.The associations were still significant after 10 000 permutations.Conclusions Although preliminary,our results provide evidence for association between the EGF gene and intelligence in patients with major depression.Genetic variation in the EGF gene may increase the susceptibility of major depression.

Aerobic biodegradation of di-n-butyl phthalate by Xiangjiang River sediment and microflora analysis

Di-n-butyl phthalate (DBP),one of phthalate acid esters (PAEs),was investigated to determine its biodegradation rate using Xiangjiang River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated with an initial concentration of DBP of 100 mg/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the degraded products were analyzed by GC/MS. Subsequently,the microbial diversity of the enrichment culture was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results reveal that almost 100% of DBP is degraded after merely 3 d,generating two main degraded products:mono-butyl phthalate (MBP) and 9-octadecenoic acid. After a six-month enrichment period under the pressure of DBP,the dominant family in the final enrichment culture is clustered with the Comamonas sp.,the remaining are affiliated with Sphingomonas sp.,Hydrogenophaga sp.,Rhizobium sp.,and Acidovorax sp. The results show the potential of these bacteria to be used in the bioremediation of DBP in the environment.

Ecology detection of moderate thermophilic enrichment at Lau Basin hydrothermal vents

Culturable thermophilic microorganisms were enriched from samples collected from Lau Basin hydrothermal vents in artificial seawater medium at 45 ℃ and pH 7.0. Microbial diversities of the enriched communities were defined by performing a restriction fragment length polymorphism （RFLP） analysis of 16S rRNA gene sequences with enzymes MspI and Hin6 I. A total of 14 phylotypes have been detected by the RFLP patterns identified for 16S rRNA clone libraries of the enrichment. Analysis of sequences showed that at least four bacterial divisions presented in the clones libraries. The phyla Proteobacteria and Firmicutes were the most dominant groups. The majority of the sequences included in this analysis affiliated with Gamma Proteobacteria （71%） and Bacillus （23%）. Scanning electron micrographs revealed that there were abundant rod and coceoidal forms encased in sulphur and sodium chloride precipitate. These results revealed that there were a diversity of moderate thermophilic bacterial populations thrived in Lau Basin hydrothermal vents that were previously not detected by either molecular retrieval or strain purification techniques.