Enterobacter cloacae Z0206细菌胞外多糖的体外抗氧化活性研究

本实验旨在对Enterobacter cloacae Z0206菌进行发酵培养,以制备胞外多糖,并对其体外抗氧化活性进行初步研究。通过产多糖菌E.cloacaeZ0206的深层发酵制备细菌胞外多糖,在此基础上对其清除DPPH自由基、超氧阴离子、抑制羟自由基的能力以及还原力等四个方面进行实验,评价其抗氧化活性。结果表明,深层发酵制备的E.cloacaeZ0206胞外多糖产量为6.62g/L,其在5mg/mL时对DPPH自由基和羟自由基的清除率分别达到61.57%和40.08%。提示E.cloacaeZ0206细菌胞外多糖具有显著的抗氧化能力,具有开发为抗氧化类食品或药品的潜力。

Enterobacter Cloacae Z0206细菌胞外富硒多糖的抗氧化活性

利用产多糖菌Enterobacter cloacae Z0206(E.cloacaeZ0206)的深层发酵法制备了E.cloacae Z0206细菌富硒多糖;测定了其还原能力和清除1,1-diphenyl-2-picrylhydrazyl(DPPH)自由基、超氧阴离子及羟自由基的能力.结果表明,通过深层富硒发酵、醇沉离心等制备富硒多糖SEPS的产量为9.28g/L,富硒量为2.314mg/g;E.cloacae Z0206富硒多糖对DPPH自由基和羟自由基具有较好的清除作用,在浓度为5g/L时对DPPH自由基和羟自由基的清除率分别为80.35%和84.26%,并具有较强的还原能力,但其对超氧阴离子自由基的清除能力较差.

Enterobacter cloacae B5产转糖基β-半乳糖苷酶发酵条件优化

β-半乳糖苷酶是一类非常重要的糖苷水解酶,已被广泛应用于食品工业降低乳制品中的乳糖含量.某些种类的β-半乳糖苷酶还具有转糖基活性,近年来被应用于合成低聚半乳糖和半乳糖苷化合物.通过单因子试验和正交试验,对肠杆菌Enterobacter cloacae B5产生转糖基β-半乳糖苷酶的培养基组成及发酵条件进行了优化.结果表明,以无机盐溶液I(CaCl20.011%、MnSO40.0001%、MgSO4.7H2O0.03%、KH2PO40.005%、FeSO4.7H2O0.003%)、乳糖1.5%、酵母粉2%、蛋白胨0.5%、起始pH8.5的培养基在25℃培养E.cloacaeB5菌株38h,产酶量达到最高值4.663UmL-1,大约是未优化时的3倍.通过优化产酶条件提高了全细胞酶源的酶活量,不仅为功能性低聚半乳糖的生产降低了成本,同时也为商业化β-半乳糖苷酶的大量提纯降低了成本.

聚丙烯酰胺降解菌株Enterobacter cloacae的分离鉴定

应用厌氧Hungate技术,从大庆油田聚合物配注站的熟化罐水溶液中分离到一株聚丙烯酰胺降解菌株.对该菌株进行形态、生理生化、分子生物学鉴定结果表明,菌株为G-,短杆状,无芽孢,最佳pH值为8.0,最适生长温度为40℃,具有硫酸盐还原功能,产H2S,严格厌氧,通过16S rDNA和16S^23S rDNA间隔区序列鉴定,菌株与Enterobacter cloacae有极高的相似性.初步鉴定为Enterobact-er中的新种,暂时命名为Enterobacter cloacae.红外光谱分析结果表明,菌株以聚丙烯酰胺为惟一碳源,菌株作用前后表面结构发生变化,分子链上的酰胺基水解成羧基,降解侧链,部分官能团发生改变,溶液黏度下降效果显著;GC-MS初步分析聚合物发生断链,低分子质量化合物除含双键、环氧和羰基的聚丙烯酰胺碎片外,大多属于一般丙烯酰胺低聚体的衍生物.

Candida cloacae源脂肪酸醇氧化酶基因的植物表达质粒构建及农杆菌转化研究

目的构建表达Candidacloacae源脂肪酸醇氧化酶基因的植物表达质粒及对农杆菌转化。方法脂肪酸醇氧化酶基因经RT-PCR扩增后直接克隆pET-17b载体,双酶切目的片断和植物表达载体,以T4连接酶将目的片断与载体相连接,电转化方式将重组质粒转入农杆菌。结果成功地将目的基因定向克隆到表达载体,并转入到农杆菌中。结论pET-17b载体可直接进行PCR扩增产物克隆;大分子量质粒(>12kb)可通过电转化方式有效导入农杆菌中。

Candida Cloacae长链脂肪酸醇氧化酶的结构域谱分析(英文)

目的 分析酵母CandidaCloacae中长链脂肪酸醇氧化酶的酶活性结构域。方法 利用RT PCR技术 ,从酵母Candidacloacae细胞中克隆长链脂肪酸醇氧化酶的 5个不同长度的cDNA片段。扩增这些片段的上游引物5’端引入了NheI限制性内切酶位点和起始密码ATG ,下游引物 5’端引入了NheI限制性内切酶位点。扩增产物经NheI消化后 ,被克隆进T7启动子控制下的表达质粒pET 17b中 ,转化大肠杆菌BL2 1(DE3)菌株。结果 转化大肠杆菌BL2 1(DE3)菌株表达出 5个不同长度的长链脂肪酸醇氧化酶的羧基端肽段 ,其氨基酸残基数分别为5 35AA(5 0KD)、4 73AA(43KD)、4 11AA(38KD)、30 6AA(2 6KD)和 2 16AA(18KD)。与完整的长链脂肪酸醇氧化酶(6 97AA)相比较 ,相当于它们分别从氨基端被切除 16 2、2 2 4、2 88、391和 4 81个氨基酸 ,其酶活性分别下降了 18.8%、2 0 .6 %、88.6 %、91.4 %和 99.7%。结论 结果表明随着长链脂肪酸醇氧化酶的氨基端被切除的氨基酸数增加 ,其酶活性下降 ,尤其是切除 2 2 4 2 88氨基酸序时 ,酶活性下降更明显 。

Enterobacter cloacae Z0206生物纳米单质硒的安全性及其相对生物学效价评定

本试验旨在对Enterobacter cloacae Z0206生物纳米单质硒(BNS)的安全性及其相对生物学效价进行评定。首先,以20只无特定病原体(SPF)级昆明小鼠(雌雄各占1/2,体重18~22 g)为试验动物,采用急性经口毒性试验对BNS的安全性进行评价。在此基础上,选取84只4周龄清洁级Wistar雄性大鼠,随机分为对照组(24只)和硒缺乏组(60只),硒缺乏组饲喂缺硒饲粮(硒含量为0.02 mg/kg),对照组饲喂在缺硒饲粮基础上添加亚硒酸钠(Na2SeO3)的基础饲粮(硒含量为0.15 mg/kg)。饲喂21 d后,从2组随机各选6只大鼠采样,而后将硒缺乏组剩余的54只大鼠随机分为3组,每组6个重复,每个重复3只,分别饲喂在缺硒饲粮基础上添加Na2SeO3、酵母硒(Yeast-Se)和BNS的饲粮,3组饲粮硒含量均为0.15 mg/kg,进行为期35 d的硒补偿试验。结果显示:BNS对小鼠的半数致死剂量(LD 50)>90.46 mg/kg BW(以硒计),具有较高的安全性;经过21 d的硒耗竭,与对照组相比,硒缺乏组大鼠肝脏、肾脏、肌肉中硒含量和血浆、肝脏中谷胱甘肽过氧化物酶(GPx)活性均极显著降低(P<0.01);补硒35 d后,与Na2SeO3相比,BNS可显著提高大鼠的平均日增重以及肾脏和肌肉中硒含量(P<0.05),有提高大鼠血浆和肝脏GPx活性的趋势(P>0.05),且效果稍优于Yeast-Se。相对于Na2SeO3,以血浆和肝脏中GPx活性,肝脏、肾脏、肌肉中硒含量为评价指标,得出BNS的相对生物学效价分别为112.2%、114.6%、102.0%、155.3%、143.2%,酵母硒的相对生物学效价分别为101.1%、101.7%、103.4%、149.4%、110.6%。由此得出,BNS具有较高的安全性;与Na2SeO3相比,BNS在提高大鼠的采食量、组织硒沉积以及含硒抗氧化酶活性等方面具有明显优势,且BNS的相对生物学效价优于Na2SeO3和Yeast-Se。

Isolation and identification of a bacteria strain Enterobacter cloacae I7 for degradation of hydrolyzed polyacrylamide

A bacteria strain for the degradation of hydrolyzed polyacrylamide （HPAM） was isolated from a curing pot in HPAM distribution station of Daqing Oilfield using Hungate anaerobic technique. The isolate was investigated from morphological, physiological, biochemical and molecular characterization. It is a Gram-negative, shortbacillus, non-spore-forming anaerobic bacteria with an optimum growth at 8.0 pH at 40℃. It can reduce sulfate to I-I2S. Alignment of 16S ribosomal DNA and 16S-23S ribosomal DNA intergenic spacer sequences suggests that this isolate is closely related to the Enterobacter cloacae. The isolate is identified as a new strain belonging to Enterobacter genus, temporarily named as Enterobacter cloacae 17. Analysis results of infrared spectroscopy （IR） show that the bacteria can use HPAM as the only carbon source, change the structure of HPAM polymer surface, and realize the hydrolysis of amide to carboxyl group by hydrolysis mechanism. It can degrade the side chain and change some functional groups, which obviously decreases the viscosity. GC-MS analysis indicates that the determined low-molecular weight degradation products of HPAM are polyacrylamide fragments with duplet bond, epoxy as well as carbonyl group, but most of them are acrylamide oligomer derivatives.

Rapid Identification and Subtyping of Enterobacter cloacae Clinical Isolates Using Peptide Mass Fingerprinting

Objective To establish a domestic database of Enterobacteria cloacae （E. cloacae）, and improve the identification efficiency using peptide mass fingerprinting. Methods Peptide mass fingerprinting was used for the identification and subtyping of E. cloacae. Eighty-seven strains, identified based on hsp60 genotyping, were used to construct and evaluate a new reference database. Results Compared with the original reference database, the identification efficiency and accuracy of the new reference database was greatly improved at the species level. The first super reference database for E. cloacae identification was also constructed and evaluated. Based on the super reference database and the main spectra projection dendrogram, E. cloacae strains were divided into two clades. Conclusion Peptide mass fingerprinting is a powerful method to identify and subtype E. cloacae, and the use of this method will allow us to obtain more information to understand the heterogeneous organism E. cloacae.

Emerging Carbapenem-Resistant <i>Enterobacter cloacae</i>Producing OXA-48-, VIM- and IMP-Type-<i>β</i>-Lactamases in Eastern Cape Hospitals in South Africa

Introduction: Enterobacter cloacae strains have been isolated from Eastern Cape hospitalised patients. Methodology: We have molecularly characterised blaOXA-48-, blaIMP- and blaVIM-expressing E. cloacae isolates demonstrating resistance to carbapenems from five hospitals by multilocus sequence typing. Organism identification and antimicrobial susceptibility testing was done using automated systems and the isolates were screened for carbapenemases using either conventional or real-time PCR and then typed using multilocus sequence typing. Further characterisation of IMP-type-producing E. cloacae isolates, an unusual occurrence in South Africa, was performed by pulsed-field gel electrophoresis. Results and Conclusion: Twenty-five E. cloacae isolates from 24 patients were investigated. Eighteen (72%) isolates harboured either one of the following genes: blaIMP, blaVIM or blaOXA-48. Multilocus sequence typing data and pulsed-field gel electrophoresis showed that several strains from the same geographical region and hospitals were genetically related.

A Stably Transgenic INA Enterobacter cloacae for Control of Insect Pests

Using the minitransposon pMini-Tn5 and the ice-nucleation active (INA) gene of iceA, a suicide recombinant plasmid pTnice1 was constructed, which has the ability of broad-host-range conjugal mobilization and integration of iceA into chromosomal DNA of many gram-negative bacteria by Tn5 transposition. We used this plasmid to integrate the iceA into chromosomal DNA of Ent. cloacae and obtained the transgentic strain Enc1.2022 ina. In this transgenic Ent. cloacae, iceA would never be transferred elsewhere through transposition, and constantly expressed high ice nucleation activity even in the absence of antibiotic pressure. The transgenic strain was ingested by corn borer larvae. Over the 7 d after ingestion, the mean supercooling points (SCPs) of the larvae was about 10℃ higher than those of larvae treated with distilled water (control). The maintenance of these high SCPs was related to the stable gut colonization of transgenic strain. At 6th day post ingestion, the larva was exposed at 5 or 7℃ for 12 h, the percentages of larvae frozen to death were 85 and 100%, respectively. In contrast, none or a small proportion of control larvae was frozen to death under the same conditions. Further studies demonstrated that this transgenic strain bore weak epiphytic ability. Therefore, this genetically engineered strain may be a promising candidate for control of insect pests in agricultural fields.

Surface Microstructure and Component Changes of Chromium-resistant Enterobacter Cloacae CYS-25 Strain

Enterobacter cloacae CYS-25 strain was isolated from a chromate plant. This bacterium was capable of resisting high hexavalent chromium concentration and reducing Cr（VI） under aerobic condition. CrO4^2- stimulated the increase of bacterial size and production of compact convex paths containing chromium on the bacterial surface. The increase of bacterial size was caused by integrative growth but not extracellular polymeric substance hyperplasia. IR and SDS-PAGE analyses showed the extracellular polymeric substance （EPS） components were mainly proteins and had no obvious changes whether the strains were induced by Cr（VI） or not. The EPS was amorphous and contained trivalent chromium. Under CrO4^2- growth condition, the extracellular substance of Enterobacter cloacae CYS-25 strains and Cr（VI） had redox reaction. The products were Cr^3＊-protein complexes which formed a piece of compact convex paths on the surface of bacteria and prevented Cr（VI） from entering into cells.

Rapid Method for the Determination of Total Monosaccharide in <i>Enterobacter cloacae</i>Strains Using Fourier Transform Infrared Spectroscopy

Fourier Transform Infrared Spectroscopy (FTIR) was used to quantify total monosaccharide content in the bacterium Enterobacter cloacae and several of its biofilm mutants. Bacterial biofilm samples were grown on trypticase soy agar, and 30 μL aliquots of aqueous sample bacterial plus biofilm were deposited into the center of barium fluoride crystals and dried at 50°C for 1-hour before being scanned by FTIR. The total amounts of monosaccharides were estimated using the absorbance of the mono-saccharide peak, 1192 - 958 cm–1, and normalized using the amide II peak, 1585 - 1483 cm–1. This method provided a linear correlation between the absorbance of the monosaccharide peak and concentration of monosaccharide in standard monosaccharides, fructose, glucose, mannose, and rhamnose, over a concentration range of 0.5 - 2.0 mg/mL.

鲫鳃出血病2种病原菌的分离及鉴定

从患有鳃出血病的鲫鳃组织分离出2种革兰氏阴性杆菌,并进行形态特征及16S r RNA基因序列分析。结果显示,这2种病原菌为维氏气单胞菌(Aeromonas veronii)和阴沟肠杆菌(Enterobacter cloacae)。体外溶血试验结果显示,2种菌对鱼的红细胞都有较强的溶血作用,且维氏气单胞菌的溶血速率明显高于阴沟肠杆菌。人工感染试验显示,这2种菌都具有较强的毒力,两者混合感染比单独感染致病率更高;但单独感染时阴沟肠杆菌比维氏气单胞菌引起的鳃出血症状更明显。5种常用水产药的耐药性结果表明两种菌都有一定的耐药性,但是维氏气单胞菌的耐药性更强。

大陆地区茭白新纪录病害——茭白细菌性基腐病

2016年,在湖北省武汉地区发现一种茭白(Zizania latifolia)新病害,鉴定确认该病害是中国大陆地区茭白的一种病害新纪录——茭白细菌性基腐病(Enterobacter cloacae)。对茭白细菌性基腐病的发生及为害情况进行了初步调查。

土壤源孔雀石绿脱色菌的筛选及脱色条件分析

从土壤来源的细菌中,筛选可使孔雀石绿(MG)脱色的菌株,结果得到1株阴沟肠杆菌(Enterobacter cloacae)(S1-2)对MG有较强的脱色能力。通过MG被脱色前后溶液吸光度的变化衡量脱色率,用单一变量法分析影响菌株S1-2发挥MG脱色作用的不同条件。结果表明,菌株S1-2在36 h内可使1100 mg/L的MG完全脱色,处理后的MG对解淀粉芽孢杆菌、壁芽孢杆菌抑制率降低了43.98%~48.21%。用300 mg/L的MG进行脱色条件分析发现,按0.5%~7.0%接菌,脱色率达91.67%~93.91%;不同pH培养环境中,该菌在pH 6、7时对MG脱色率为90.02%~94.54%;在20~40℃条件下培养,该菌对MG脱色率达84.61%~94.56%;在6~18 g/L的NaCl浓度下,该菌对MG的脱色率达91.85%~93.77%。

罗氏沼虾病原阴沟肠杆菌药物敏感性测定与分析

采用纸片扩散法(K-B法)测试了2017年春季分离自江苏省高邮市罗氏沼虾(Macrobrachium rosenbergii)育苗场的5株阴沟肠杆菌(Enterobacter cloacae)对35种抗菌类药物的敏感性,并采用试管稀释法测定了6种抗菌药物对分离菌株WJ1的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),结果显示:恩诺沙星对阴沟肠杆菌的杀菌效果最好,最小杀菌浓度为4 mg/L;其次是诺氟沙星,最小杀菌浓度为7 mg/L;盐酸土霉素和氟苯尼考的最小杀菌浓度分别为8 mg/L和10 mg/L;红霉素和头孢曲松对阴沟肠杆菌杀菌效果最差。

Identification of Cloaca Bacteria from Candidate Releasing Chinese Alligators

The Chinese alligator （Alligator sinensis） is a critically endangered species in China. Wild populations of Chinese alligator are on the edge of extinction. Through a release program, some captive-bred alligators will be selected and released into the wild to supplement and renew natural populations. The purpose of this study was to provide data to select healthy individuals for release. Through bacteriological and molecular identification, six different genera, eight species and an unclassified bacterium were identified in 13 bacterial strains, which were isolated from the cloaca of 25 Chinese alligators. One genus and four species were identified in eight bacterial strains, which were isolated from the water where the alligators live. According to the analysis, except for the unclassified bacterium, the other bacteria from the cloaca were not pathogenic and were different from the bacteria isolated from the water. Thus, it was concluded that the 24 Chinese alligators were healthy, and could be selected to be released into the wild. As subject AS 12 was identified carrying an unclassified bacteria, of which the characteristics were unknown, it was suggested that the AS 12 individual not be released.

Detection,isolation,and identification of cadmium-resistant bacteria based on PCR-DGGE

This study focused on the screening of cadmium-resistant bacterial strains from Pb-Zn tailing. We investigated the diversity of microbial community inhabiting Dong-san-cha Pb-Zn tailing in Beijing, China, by polymerase chain reaction-denaturing gradient gel electrophoresis （DGGE） of 16S rRNA gene of bacterial strain, and found two dominant strains in the DGGE profile. Using special culture media, we isolated two strong cadmium-resistant bacterial strains. On the basis of morphological, physiological, and biochemical characteristics, BIOLOG, and 16S rDNA sequencing, the two strains were identified as Bacillus cereus and Enterobacter cloacae. Minimal inhibitory concentrations （MICs） of heavy metals for the bacteria were determined. E. cloacae showed higher MIC values for heavy metals and a larger range of antibiotic resistance than B. cereus.

Recurrent surgical site infection after anterior cruciate ligament reconstruction: A case report

BACKGROUND Surgical site infections following anterior cruciate ligament(ACL)reconstruction are an uncommon but potentially devastating complication.In this study,we present an unusual case of recurrent infection of the knee after an ACL reconstruction,and discuss the importance of accurate diagnosis and appropriate management,including the issue of graft preservation versus removal.CASE SUMMARY A 33-year-old gentleman underwent ACL reconstruction using a hamstring tendon autograft with suspensory Endobutton fixation to the distal femur and an interference screw fixation to the proximal tibia.Four years after ACL reconstruction,he developed an abscess over the proximal tibia and underwent incision and drainage.Remnant suture material was found at the base of the abscess and was removed.Five years later,he re-presented with a lateral distal thigh abscess that encroached the femoral tunnel.He underwent incision and drainage of the abscess which was later complicated by a chronic discharging sinus.Repeated magnetic resonance imaging revealed a fistulous communication between the lateral thigh wound extending toward the femoral tunnel with suggestion of osteomyelitis.Decision was made for a second surgery and the patient was counselled about the need for graft removal should there be intraarticular involvement.Knee arthroscopy revealed the graft to be intact with no evidence of intra-articular involvement.As such,the decision was made to retain the ACL graft.Re-debridement,excision of the sinus tract and removal of Endobutton was also performed in the same setting.Joint fluid cultures did not grow bacteria.However,tissue cultures from the femoral tunnel abscess grew Enterobacter cloacae complex,similar to what grew in tissue cultures from the tibial abscess five years earlier.In view of the recurrent and indolent nature of the infection,antibiotic therapy was escalated from Clindamycin to Ertapenem.He completed a six-week course of intravenous antibiotics and has been well for six months since surgery,with excellent knee function and no evidence of any further infection.CONCLUSION Prompt and accurate diagnosis of surgical site infection following ACL reconstruction,including the exclusion of intra-articular involvement,is important for timely and appropriate treatment.Arthroscopic debridement and removal of implant with graft preservation,together with a course of antibiotics,is a suitable treatment option for extra-articular knee infections following ACL reconstruction.