• 제목/요약/키워드: coli B

검색결과 1,637건 처리시간 0.03초

Optimization and High-level Expression of a Functional GST-tagged rHLT-B in Escherichia coli and GM1 Binding Ability of Purified rHLT-B

  • Ma Xingyuan;Zheng Wenyun;Wang Tianwen;Wei Dongzhi;Ma Yushu
    • Journal of Microbiology
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    • 제44권3호
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    • pp.293-300
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    • 2006
  • The Escherichia coli heat-labile enterotoxin B subunit (HLT-B) is one of the most powerful mucosal immunogens and known mucosal adjuvants. However, the induction of high levels of HLT-B expression in E. coli has proven a difficult proposition. Therefore, in this study, the HLT-B gene was cloned from pathogenic E. coli and expressed as a fusion protein with GST (glutathion S-transferase) in E. coli BL2l (DE3), in an attempt to harvest a large quantity of soluble HLT-B. The culture conditions, including the culture media used, temperature, pH and the presence of lactose as an inducer, were all optimized in order to obtain an increase in the expression of soluble GST-rHLT-B. The biological activity of the purified rHLT-B was assayed in a series of GMI-ELISA experiments. The findings of these trials indicated that the yield of soluble recombinant GST-rHLT-B could be increased by up to 3-fold, as compared with that seen prior to the optimization, and that lactose was a more efficient alternative inducer than IPTG. The production of rHLT-B, at 92 % purity, reached an optimal level of 96 mg/l in a 3.7 L fermentor. The specific GM1 binding ability of the purified rHLT-B was determined to be almost identical to that of standard CTB.

수생조류에서 분리한 대장균의 항균제 내성 및 Tetracycline 내성인자의 분포 (Antimicrobial resistance and distribution of tetracycline resistance determinants in Escherichia coli isolated from aquatic birds)

  • 조재근;이상민;김기석
    • 대한수의학회지
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    • 제48권3호
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    • pp.295-303
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    • 2008
  • One hundred and sixty nine Escherichia (E.) coli strains isolated from fecal samples of aquatic birds in Geumho river basin and Dalseong park were tested by agar dilution method to determine their susceptibility patterns to 14 antimicrobial agents. The distribution of tetracycline resistance determinants (tetA, tetB, tetC, tetD and tetE) were also examined by PCR in 76 tetracycline-resistant ($TC^r$) E. coli isolates. The high resistance was observed in tetracycline, cephalothin and ampicillin (45.0~36.7%). Resistance of E. coli isolates derived from Dalseong park to tetracycline, cephalothin, ampicillin and streptomycin (65.7~44.8%) were significantly higher than those isolated from Geumho river basin (31.4~14.7%). About seventy percent (70.4%) of the strains isolated were resistant to one or more drugs tested. Thirty (39.5%) of 76 $TC^r$ E. coli isolates which were resistant to one or more drugs transferred all or a part of their resistance patterns to the recipient strain of E.coli J53 by conjugation. All of $TC^r$ E. coli isolates contained at least one or more of 5 tet genes examined. The most common genes found in these isolates were tetA (60.6%) and followed by tetB (7.9%) and tetC (1.3%). However, tetD and tetE were not found in any of the isolates tested. Twenty one (27.6%) of $TC^r$ E. coli isolates had two determinants, tetA/tetB (20 strains), tetA/tetC (1 strain). And two strains (2.6%) contained three determinants (tetA/tetB/tetC).

대구지역 야생조류에서 분리된 대장균의 항생제 내성 조사 (Antimicrobial resistance of Escherichia coli isolated from wild birds in Daegu)

  • 김경희;임현숙;이정우;박대현;양창렬;조재근
    • 한국동물위생학회지
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    • 제44권4호
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    • pp.209-216
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    • 2021
  • This study was aimed to investigate occurrence and the antimicrobial resistance of Escherichia coli isolates obtained from the feces of wild birds in Daegu. In total, 98 E. coli isolates (17.9%) were obtained from 547 fecal samples of wild birds. The E. coli carried by the birds showed a relatively high rate of antimicrobial resistance to tetracycline (27.6%) and ampicillin (21.4%). Drug resistance of the isolates to the others (penicillins, cephems, carbapenems, aminoglycosides, quinolones, sulfonamides and phenicols) resulted in the rates less than 20%, and all isolates were susceptible to imipenem, ciprofloxacin, cefotetan, and amikacin. Approximately, 45% E. coli among the isolates were resistant to one or more drugs tested. The higher rate of tetracycline resistance led us to determine the prevalence of the tet genes (tetA, tetB, tetC, tetD and tetE) in the tetracycline-resistant E. coli isolates by using PCR. All isolates of the tetracycline-resistant E. coli contained at least one or more of these tet genes examined. The most prevalent one was tetA (59.3%), and followed by tetB (7.4%) when tested with the selected 5 tet genes. Except tetA and tetB, however, the remaining tet genes (tetC, tetD, and tetE) tested were not found in this study. Nine isolates among the tetracycline-resistant E. coli contained the two (tetA and tetB) determinants of tetracycline resistance, simultaneously.

R-plasmid pSBK203의 ori 부위 재조합 및 이를 이용한 E.coli와 B.subtilis 간의 Shuttle-Vector 구성 (Cloning of ori region of R-plasmid pSBK203 and construction of new shuttle-vectors for E. coli & B. subtilis using cloned fragments)

  • 권동현;석종성;변우현
    • 미생물학회지
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    • 제25권4호
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    • pp.262-273
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    • 1987
  • pBR 322와 pBD9을 이용하여 Staphylococcus aureus에서 분리된 chloramphenicol 저항성(Cmr) plasmid인 pSBK 203상의 ori 부위를 cloning하였다. 또한 E. coli 내에서도 발현하는 pSBK 203상의 Cm 저항성 부위 및 cloning 된 ori 부위를 pBR 322에 재조합시켜 E. coli와 그람양성균인 Bacillus subtilis 양쪽 모두에서 복제되고 또 항생물질에 대한 저항성도 각각 발현되는 shuttle vector 구성을 시도하였다.

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Prevalence and Cytotoxic Effects of Some Colibactin and cnf Genes among Escherichia coli Isolated from Urinary Tract Infections

  • Alhadidi, Hiba A.S.;Al-Qaysi, Safaa A. S.;Al-Halbosiy, Mohammad M. F.
    • 한국미생물·생명공학회지
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    • 제50권2호
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    • pp.283-292
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    • 2022
  • Colibactins (clb) and Cytotoxic Necrotizing Factors (cnf) are virulence factors that impact cell cycle through cellular differentiation, proliferation, and apoptosis. Urinary tract infections (UTIs) are the most common among type of infection among outpatients, with a lifetime incidence of about 60-65% in adult females. Here, we sought to isolate uropathogenic Escherichia coli (UPCE) from urine specimens and investigates the prevalence of clb A, B and cnf 1, 2 genes among these isolates. A total of 110 E. coli isolates were collected from patients with UTIs. All the isolates were examined for their hemolytic activity and only 46 isolates showed a halo zone of hemolysis on blood agar. The collected UPEC isolates were screened for the existence of clb A, B and cnf genes. The results revealed that out of 110 isolates, 28 harbored the clbA gene, 40 harbored clb B, and 24 isolates harboured cnf1. 13 isolates harbored clbA, clbB, and cnf1 genes, while no cnf2 gene was detected among isolates. The molecular detection revealed that 8 out of 28 hemolytic isolates carrying the clbA, 11 out of 40 were carrying clbB, 1 out of 24 were carrying cnf 1, and 5 out of 9 carrying clbA+clbB. Furthermore, 7 out of 13 isolates were hemolytic and carrying clbA, clbB, and cnf1 genes. Finally, we investigated the cytotoxicity of E. coli harboring clb and cnf genes, eukaryotic REF cells were exposed to E. coli producing colibactin, which induces DNA damage and leads to cell cycle arrest, senescence and death.

대장균(E. coli B)의 항생제처리가 $T_3$ phage의 부착에 미치는 영향 (Treatment of E. coli B with two Antibiotics and their Influence on $T_3$ phage Absorption)

  • 정상진;김은수
    • Applied Microscopy
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    • 제10권1_2호
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    • pp.19-25
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    • 1980
  • E. coli B was treated with colistin and kanamycin and the influence of these antibiotics on the absorption of $T_3$ phage was studied using the plaque counting method and the electron microscope. E. coli B treated with colistin was sharply inhibited on phage absorption and cell walls were severely damaged showing some spiny appearance around the walls. No influence of kanamycin was noted on phage absorption. Bacterial cells treated with kanamycin showed wave form in the structure of walls and a profound change was noted in the cytoplasm where it was concentrated along the periphery of the inner wall leaving the center of the cell to appear almost empty.

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Grapefruit 종자 추출물의 항균작용 및 미생물 생리기능에 미치는 영향 (Antimicrobial activities and effect of grapefruit seed extract on the physiological function of microorganism)

  • 김영록;조성환
    • 한국식품저장유통학회지
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    • 제3권2호
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    • pp.187-193
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    • 1996
  • To investigate the antimicrobial activities and effect of grapefruit seed extract(GFSE) on the physiological function of microorganism, antimicrobial activity, fatty acids of bacterial cell lipid and amino acids of bacterial cell protein were measured. The change of cell morphotype was observed by transmission electron microscope. GFSE was very stable on the wide range temperture and pH. The growth rate of E. coli and B. suvtilis were decreased above 40ppm GFSE There fore, minimum inhibitory concentration (MIC) of the E. coli and B. subtilis to GFSE were determined around 40ppm. In the change of fatty acids quantities, hexadecanoate was significantly decreased on the treatment compared with control in case of E. coli, whereas tridecanoate was not detected in case of B. subtilis. In the change of amino acids quantities, alanine, glutamic acid, glycine, lysine were decreased on the treatment compared with control in case of E. coli and B. subtilis Transmission electron microsgraphs(TEM) showed the microbial cells were destroyed by GFSE.

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Evaluating the Role of Curcum Powder as a Protective Factor against Bladder Cancer - An Experimental Study

  • El-Mesallamy, Hala;Salman, Tarek M.;Ashmawey, Abeer M.;Osama, Nada
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권10호
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    • pp.5287-5290
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    • 2012
  • Throughout human history, plant products have been used for many purposes including as medicines. Herbal products and spices can be used as preventive agents against cancer due to their antimicrobial, antioxidant and antitumorigenic properties. This study was designed to evaluate the potential protective effect of curcum in rats administered nitrosamine precursors; dibutylamine (DBA) and sodium nitrate (NaNO3); and infected with Escherichia coli (E. coli) and also to monitor changes in nuclear factor the Kappa B p65 (NF-${\kappa}B$ p56) pathway and its downstream products, Bcl-2 and interleukin-6 (IL-6), in parallel with nitrosamine precursors, E. coli and curcum treatment. Rats were divided into three groups (n=25 each; except of control group, n+20). Group I a normal control group, group II administered DBA/NaNO3 in drinking water and infected with E. coli and group III was administered DBA/NaNO3 in drinking water, infected with E. coli and receiving standard diet containing 1% curcum powder. Histopathological examination reflected that the curcum treated group featured a lower incidence of urinary bladder lesions, and lower levels of NF-${\kappa}B$, Bcl-2 and IL-6, than the group receiving nitrosamine precursor and infected with E. coli. These findings suggested that curcum may have a protective role during the process of bladder carcinogenesis by inhibiting the NF-${\kappa}B$ pathway and its downstream products.

대장균에서 4-nitroquinoline 1-oride의 변이원성에 대한 숙지황 물추출물의 항돌연변이 작용특성 (Antimutagenic Mechanism of Water Extract from Rehmannia glutinosa Liboshitz on 4-nitroquinoline 1-oxide Induced Mutagenesis n E. coli B.r)

  • 안병용;한종현;최동성
    • KSBB Journal
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    • 제16권5호
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    • pp.486-492
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    • 2001
  • 숙지황 물추출물로부터 분리된 fraction(RG-III) 의 항돌연변이원성의 기작을 E. coli GW, B/r 균주를 이용하여 조사하였다. SOS 유도를 반영하는 $\beta$-galactiosidase 활성이 E. coli GW 1060, 1103, 1107, 1105에서 증가되지 않았다. RG-III는 RecA는 단백질의 합성을 증폭시키거나 LexA 산물의 분해를 저해하지 않았으므로 SOS en 기능의 발현이 영향을 미치지 못했다. 따라서 DNA 수복의 경로가 다른 E. coli B.r 변이주를 사용하여 4NQO와 MNNG에 대한 세포내 항돌연변이원성과 생존효과를 조사하였다. ZA159(uvrB, 최)를 제외한 WP2, WP2s, WP67, CM561, CM611에서 RG-III는 4NQO에 대한 생존력을 미약하게나마 증가시켰으나, 이러한 생존력 재활성을 수복모드에 의해 설명할 수 없었다. WP2, WP2s, WP67, CM561, CM611에서 RG-III는 MNNG로 유도된 돌연변이원성과 치사력을 증가시킴에도 불구하고 ZA159(uvr B, chl)에서는 감소시켰다. 4NQO의 변이원성을 두드러지게 억제하였으나 ZA159(uvr B, chl)에서 상승효과가 상대적으로 감소되었다. 이러한 결과들은 RG-III가 4NQO의 변이원성을 방어하는 차단제임을 시시하여, chl 산물의 기능과 유사한 작용을 하는 것으로 사료된다.

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Cloning and Functional Characterization of Putative Escherichia coli ABC Multidrug Efflux Transporter YddA

  • Feng, Zhenyue;Liu, Defu;Liu, Ziwen;Liang, Yimin;Wang, Yanhong;Liu, Qingpeng;Liu, Zhenhua;Zang, Zhongjing;Cui, Yudong
    • Journal of Microbiology and Biotechnology
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    • 제30권7호
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    • pp.982-995
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    • 2020
  • A putative multidrug efflux gene, yddA, was cloned from the Escherichia coli K-12 strain. A drug-sensitive strain of E. coli missing the main multidrug efflux pump AcrB was constructed as a host and the yddA gene was knocked out in wild-type (WT) and drug-sensitive E. coliΔacrB to study the yddA function. Sensitivity to different substrates of WT E.coli, E. coliΔyddA, E. coliΔacrB and E. coliΔacrBΔyddA strains was compared with minimal inhibitory concentration (MIC) assays and fluorescence tests. MIC assay and fluorescence test results showed that YddA protein was a multidrug efflux pump that exported multiple substrates. Three inhibitors, ortho-vanadate, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and reserpine, were used in fluorescence tests. Ortho-vanadate and reserpine significantly inhibited the efflux and increased accumulation of ethidium bromide and norfloxacin, while CCCP had no significant effect on YddA-regulated efflux. The results indicated that YddA relies on energy released from ATP hydrolysis to transfer the substrates and YddA is an ABC-type multidrug exporter. Functional study of unknown ATP-binding cassette (ABC) superfamily transporters in the model organism E. coli is conducive to discovering new multidrug resistance-reversal targets and providing references for studying other ABC proteins of unknown function.