• Title/Summary/Keyword: Acid-resistant

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Lack of O-Polysaccharide Renders Bradyrhizobium japonicum More Resistant to Organic Acid Stress

  • OH , EUN-TAEX;JU, YOUNG-JUN;KOH, SUNG-CHEOL;KIM, YONG-HWI;KIM, JONG-SUL;SO, JAE-SEONG
    • Journal of Microbiology and Biotechnology
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    • 제14권6호
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    • pp.1324-1326
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    • 2004
  • In previous studies, we isolated an isogenic LPS mutant of Bradyrhizobium japonicum 61A101C, which was completely devoid of O-polysaccharide and had altered cell surface characteristics. Subsequently, the mutated gene was identified, cloned, and used to complement the LPS mutant strain JS314 to restore the phenotype. Since it has been reported that in Escherichia coli LPS O-polysaccharide is involved in resistance to an organic acid such as acetic acid under low pH (Barna et al., Molecular Microbiology 43: 629-640, 2002), we compared the organic acid resistance of the three B. japonicum strains; wild-type 61A101C, the LPS mutant JS314, and the complemented strain to determine whether the role of O-polysaccharide in the resistance to organic acid could be generalized. Growth of all three strains was inhibited by the presence of 3 mM acetic acid under acidic condition (pH 5.5). To our surprise, however, in the presence of 2 mM acetic acid, wild-type and the complemented strains did not grow while the $LPS^-$ mutant showed a significant growth. Therefore, unlike in E. coli, the lack of O­polysaccharide of LPS appears to render B. japonicum more resistant to organic acid.

Evaluation of Lactic Acid Bacteria for the Resistance to Endocrine Disruptors

  • Kim, Su-Won;Min, Byung-Tae;Yoo, Min
    • 대한의생명과학회지
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    • 제8권2호
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    • pp.95-99
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    • 2002
  • Endocrine disruptors are chemicals which can be found in our normal daily life. They can be easily ingested through plastic food containers, pesticides, etc. They include DDT, bisphenol A, benzophenone and phenylphenol, etc. Endocrine disruptor can be very harmful and toxic because it disrupts the normal function of the endogenous endocrine system. It has been reported that endocrine disruptor can cause the fatal strike in reproductive system central nervous system and the other part of the body. We have examined if the growth of lactic acid bacteria could be resistant to the endocrine disruptor. We have used Lactobacillus delbruekii as an experimental strain and benzophenone and phenylphenol for the comparison purpose. Experiments included the evaluation of turbidity, absorbance and actual cell counts. Although Lactobacillus delbruekii showed the higher resistance to benzophenone than phenylphenol it was still resistant to both benzophenone and phenylphenol. Because the experimental concentrations of benzophenone and phenylphenol were so high to compare with the actual concentration we meet in daily life, Lactobacillus delbruekii was considered to be sufficient to survive in the environmental concentration of these endocrine disruptors. This study should contribute to the development of fermented beverage with beneficial effect by lactic acid bacteria.

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Screening and Characterization of Pro biotic Lactic Acid Bacteria Isolated from Korean Fermented Foods

  • Lim, Sung-Mee;Im, Dong-Soon
    • Journal of Microbiology and Biotechnology
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    • 제19권2호
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    • pp.178-186
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    • 2009
  • To examine their potential as probiotics, acid and bile tolerance, antibiotics resistance, adhesion capacity to Caco-2 and HT-29, and antibacterial activity, of LAB isolated from Korean fermented foods such. as dongchimi, kimchi, Meju, and doenjang were assayed against foodborne pathogenic bacteria. DC 55, DC 136, DC 222, KC 21, KC 24, KC 34, KC 43, KC 117, MJ 54, MJ 301, SP 33, and SP 170 strains were resistant to acid and bile conditions. In particular, DC 55, DC 136, KC 24, KC 43, and MJ 301 strains were highly resistant to higher than 20 ${\mu}g/ml$ concentrations of vancomycin, streptomycin sulfate, or amoxicillin, whereas, DC 222, KC 21, KC 34, KC 117, MJ 54, and SP 33 strains were susceptible to lower than 2 ${\mu}g/ml$ concentrations of those antibiotics. The adhesion to HT-29 and Caco-2 cells varied with the strains tested in a strain-dependent manner. The highest level of adhesion was observed with DC 55, KC 21, KC 24, and MJ 301 strains, having higher than 50% of adhesion to HT-29 or Caco-2 cells. In addition, Staphylococcus aureus was the most sensitive to KC 21, showing an inhibition of about 70%, and the antibacterial activity of KC 21 against S. aureus resulted most likely from both organic acids and bacteriocin. Based on its phenotypic characteristics and utilization of various sugars, the KC 21 strain was identified as Lactobacillus plantarum.

Ciprofloxacin 내성 대장균에서 Sequence Type과 Fluoroquinolone 내성의 분석 (Analysis of Sequence Type and Fluoroquinolone Resistance in Ciprofloxacin-Resistant Escherichia coli)

  • 조혜현
    • 대한임상검사과학회지
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    • 제53권3호
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    • pp.217-224
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    • 2021
  • 전 세계적으로 fluoroquinolone (FQ) 내성 그람음성균이 출현하고 있는 가운데, 최근 우리나라에서 FQ 내성 E. coli의 증가 추세는 심각한 우려를 낳고 있다. 이에 본 연구에서는 2018년 6월부터 12월까지 대전지역의 3차 병원에서 분리된 ciprofloxacin 내성 E. coli 56균주를 대상으로, 역학관계와 FQ 내성 결정인자의 양상을 조사하였다. 역학관계를 확인하기 위해 multilocus sequence typing (MLST)을 실시하였다. PCR과 염기서열 분석은 gyrA, gyrB, parC, parE 유전자의 QRDR에서 염색체상의 돌연변이와 aac(6)-Ib-cr, qepA, qnrA, qnrB, qnrC, qnrD 및 qnrS와 같은 PMQR 유전자의 빈도를 확인하였다. MLST 분석 결과, 12개의 ST를 확인하였으며, 이 중 가장 우세한 ST는 ST131 (31/56, 55.4%)이었고, 순차적으로 ST1193 (13/56, 23.2%), ST405 (3/56, 5.4%)의 결과를 보였다. ciprofloxacin 내성 E. coli 56균주 중 gyrA 유전자에서 83번째 아미노산인 serine (S)이 leucine (L)으로, 87번째 아미노산인 aspartic acid (D)가 asparagine (N)으로 치환되고, parC 유전자에서 80번째 아미노산인 serine (S)이 isoleucine (I)으로, 84번째 아미노산인 glutamic acid (E)가 valine (V)으로 치환된 결과(29/56, 51.8%)가 가장 빈번하게 확인되었고, aac(6)-Ib-cr (19/56, 33.9%)은 가장 흔한 PMQR 유전자로 확인되었다. 이러한 FQ 내성 결정인자의 결과는 다른 클론과 비교하여 ST131에서 더 빈번하게 확인되었다. ciprofloxacin 내성 E. coli 균주에 대한 역학적 특성의 지속적인 모니터링과 FQ 내성 결정인자에 대한 추가 연구가 필요할 것으로 사료된다.

경북지방 환돈에서 분리한 Salmonella Typhimurium의 생화학적 성상 및 약제내성 패턴 (Pattern of antimicrobial resistance and biochemical characteristics of Salmonella Typhimurium isolated from diseased pigs in Gyeongbuk province)

  • 김성국;엄현정;김순태;장영술;조민희
    • 한국동물위생학회지
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    • 제33권1호
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    • pp.51-57
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    • 2010
  • Salmonella Typhimurium is a virulent pathogen for human and animal. We studied serotypes, biochemical characteristics, and antimicrobial resistance of S. Typhimurium isolated from diseased pigs in Gyeongbuk province over 1998 to 2008. One hundred sixteen isolates were identified as S. Typhimurium by biochemical characteristics and serotypes from 90 farms. The biochemical characteristics of S. Typhimurium isolates was production of $H_2S$, indole-negative, fermentation of mannitol, dulcitol, sorbitol, inositol, rhamnose, and maltose, and ornithine decarboxylase. At antimicrobial susceptibility test, the majority of isolates were highly susceptible to amoxicillin/clavulanic acid, cefepime, ciprofloxacin, while were highly resistant streptomycin, cephalothin, enrofloxacin, nalidixic acid, apramycin, chloramphenicol, tetracycline. The isolates were divided into 65 resistant patterns and 47 of the isolates were shown as a DT104 ASSSuT resistant phenotype.

Cytochrome b Gene-Based Assay for Monitoring the Resistance of Colletotrichum spp. to Pyraclostrobin

  • Dalha Abdulkadir, Isa;Heung Tae, Kim
    • The Plant Pathology Journal
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    • 제38권6호
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    • pp.616-628
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    • 2022
  • Resistance to pyraclostrobin due to a single nucleotide polymorphism at 143rd amino acid position on the cytochrome b gene has been a major source of concern in red pepper field infected by anthracnose in Korea. Therefore, this study investigated the response of 24 isolates of C. acutatum and C. gloeosporioides isolated from anthracnose infected red pepper fruits using agar dilution method and other molecular techniques such as cytochrome b gene sequencing, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and allele-specific polymerase chain reaction (PCR). The result showed that four isolates were resistant to pyraclostrobin on agar dilution method and possessed GCT (alanine) codon at 143rd amino acid position, whereas the sensitive isolates possessed GGT (glycine). Furthermore, this study illustrated the difference in the cytochrome b gene structure of C. acutatum and C. gloeosporioides. The use of cDNA in this study suggested that the primer Cacytb-P2 can amplify the cytochrome b gene of both C. acutatum and C. gloeosporioides despite the presence of various introns in the cytochrome b gene structure of C. gloeosporioides. The use of allele-specific PCR and PCR-RFLP provided clear difference between the resistant and sensitive isolates. The application of molecular technique in the evaluation of the resistance status of anthracnose pathogen in red pepper provided rapid, reliable, and accurate results that can be helpful in the early adoption of fungicide-resistant management strategies for the strobilurins in the field.

Selection of 5-Methyltryptophan and S-(2-Aminoethyl)-L-Cysteine Resistant Microspore-Derived Rice Cell Lines Irradiated with Gamma Rays

  • Kim, Dong-Sub;Lee, In-Sok;Jang, Cheol-Seong;Hyun, Do-Yoon;Lee, Sang-Jae;Seo, Yong-Weon;Lee, Young-Il
    • Journal of Plant Biotechnology
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    • 제5권1호
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    • pp.33-41
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    • 2003
  • Microspore-derived cell lines resistant to 5-methyltryptophan (5MT, a tryptophan analog) or S-(2-aminoethyl)-L-cysteine (AEC, a Iysine analog) were selected in rice by in vitro mutagenesis. For selection of 5MT or AEC resistant cell lines, suspension-cultured cells were irradiated with gamma rays. Thirteen 5MT resistant cell lines were selected and they were able to grow stably at 2 times higher 5MT concentration. A feedback insensitive form of anthranilate synthesis, the pathway specific control enzyme for tryptophan synthesis, was detected from the 5MT resistant lines. Contents of the free amino acids in five resistant lines (MR12-1 to MR12-5) showed a 7.4 to 46.6 times greater level than that in the control culture. Tryptophan, phenylalanine, and tyrosine levels in the shikimate pathway were 28.1 and 22.5 times higher in MR12-3 and MR12 4, respectively, than that measured in the control cells. Four AEC resistant cell lines were isolated from cultures grown on medium containing 1 mM AEC, They were able to grow stably with 2 mM AEC, while sensitive calli were inhibited by 0.5 mM AEC. Aspartate kinase activities of the resistant lines were insensitive to the natural inhibitor, Iysine, and accumulated 2.2 to 12.9-fold higher levels of free Iysine than that of the control cells. Especially, the levels of aspartate, asparagine, and methionine in the aspartate pathway showed higher accumulation in the AEC resistant lines than that in the control cells.

저항전분이 인체 혈당 조절기능에 미치는 영향 (Effect of Resistant Starch on Human Glycemic Response)

  • 이영희;오승호
    • 대한지역사회영양학회지
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    • 제9권4호
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    • pp.528-535
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    • 2004
  • In order to observe the effects of resistant starches on human glycemic response, nine female university students were investigated using cellulose (CED), resistant starch 3 (RS3D) and resistant starch 4 (RS4D) diets. Each woman's blood sugar and insulin, triacylglycerol and free fatty in plasma concentration were measured at fasting state, then 15, 30, 45, 60, 75, 90 and 120 minute after each test diet feeding. Glycemic indices of the Cellulose diet (CED: 57.9 $\pm3.00$), the Resistant starch 3 diet (RS3D: 52.6 $\pm7.9$) and the Resistant starch 4 diet (RS4D: 52.9 $\pm10.2$) were similar to each other, but they were significantly lower in comparison with those of white wheat bread diet (WWBD: 100). Insulinemic indices of the CED (49.8 $\pm8.2$), RS3D (50.0 $\pm7.3$) and RS4D (72.4 $\pm7.7$) were significantly lower in comparison with the white wheat bread diet (WWBD: 100), but among the dietary fiber diets, the insulinemic index of RS4D was significantly higher than the CED and the RS3D. Plasma triacylglycerol contents of the CED, RS3D and RS4D including WWBD showed gradual increase in tendency after lowering in early stage of each test diet feeding, but not significantly different in each dietary fiber added diet. Plasma free fatty acid contents of the CED, RS3D and RS4D including WWBD showed gradual decrease in tendency after each test diet feeding, but not significantly different by each dietary fiber added diet. In above results, we speculate that resistant starch 3 controls rapid elevation of blood sugar by delaying intestinal digestion and absorption of cellulose, but the result appears to be different from RS4 in comparison. Thus, RS3 intakes may contribute to the diet therapy of diabetic humans, but more studies on RS4 is needed in the future. (Korean J Community Nutrition 9(4): 528∼535, 2004)

한국(韓國)의 환자(患者) 및 건강인(健康人)에서 분리(分離)한 E.coli의 약제내성(藥劑耐性) 및 R Plasmids (Drug Resistance and R Plasmids of Escherichia coli in Patients and Healthy Individuals in Korea)

  • 설성용
    • 대한미생물학회지
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    • 제12권1호
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    • pp.11-18
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    • 1977
  • 항균제(抗菌劑)로 치료(治療)한 환자(患者)와 항균제(抗菌劑)를 투여(投與)받지 않은 의사(醫師) 및 학생군(學生群)으로부터 총(總) 665주(株)의 E. coli를 분리(分離)하여 약제내성(藥劑耐性) 및 R Plasmid의 분포(分布)를 조사(調査)했다. 분리주(分離株)의 약(約) 25-41%가 chloramphenicol, tetracycline, streptomycin sulfisomidine 및 ampicillin(AP)에 내성(耐性)이었고 9.5%가 kanamycin에 내성(耐性)이었으며 nalidixic acid에 내성(耐性)인 균주(菌株)는 극히 드물었다. 내성주(耐性株)는 의사(醫師) 및 학생군(學生群)에서보다 환자군(患者群)에서 월등(越等)히 높았다. 4 또는 그 이상(以上)의 약제(藥劑)에 내성(耐性)인 다제내성주(多劑耐性株)는 의사(醫師) 및 학생군(學生群)보다 환자군(患者群) 분리주(分離株)에서 월등(越等)히 많은 반면 3제(劑) 또는 그 이상(以上)의 약제(藥劑)에 내성(耐性)인 균주(菌株)의 빈도(頻度)는 3군(群) 분리주(分離株) 사이에 큰 차이(差異)가 없었다. 4제(劑) 또는 그 이상(以上)의 약제(藥劑)에 내성(耐性)인 균주(菌株)를 보유(保有)하고 있는 사람은 의사(醫師) 및 학생군(學生群)보다 환자군(患者群)에서 그 빈도(頻度)가 높았다. 거의 대부분(大部分)의 약제(藥劑) 내성주(耐性株)는 모든 내성(耐性) 특히 AP 내성(耐性)을 접합(接合)에 의하여 약제감수성(藥劑感受性)인 E. coli에 전달(傳達)했다. 다제내성(多劑耐性)을 가지는 균주(菌株)는 그 근원(根源)에 관계(關係)없이 더 높은 빈도(頻度)로 약제내성(藥劑耐性)을 전달(傳達)하는 경향(傾向)이 있었다.

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대구지방에서 분리된 Shigella의 양상과 항균제 내성 (Prevalence and Drug Resistance of Shigella in Taegu Area of Korea)

  • 전도기;박종욱;서성일;조동택;설성용;이유철
    • 대한미생물학회지
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    • 제21권4호
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    • pp.461-471
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    • 1986
  • 1973년부터 1985년 사이에 대구지방에서 분리된 Shigella는 약 1,200주였는데, 대부분이 Shigella flexneri였고, S. sonnei는 약 20%였으며, S. dysenteriae와 S. boydii는 극히 적었다. 분리균의 95%이상이 chloramphenicol(Cm), tetracycline(Tc), streptomycin(Sm), sulfisomidine(Su), ampicillin(Ap), trimethoprim(Tf) 등의 전부 또는 일부 약제에 내성이었으며, kanamycin, nalidixic acid(Na)와 rifampin(Rf)에 내성인 균주는 소수 있었으나, cephaloridine, gentamicin, amikacin 등에 내성인 균주는 없었다. 1973년에 분리된 균은 약 절반이 약제내성이었으나, 1977년 이후 분리된 균은 95% 이상이 약제내성이었다. 1977년 까지는 Cm, Tc, Sm 및 Su의 4제 내성균이 가장 많았으나 1978년 부터는 Cm, Tc, Sm, Su, Ap 및 Tp의 6제 내성균이 가장 많았다. 약 75%의 균이 그 약제내성을 접합에 의하여 Escherichia coli에 전달하였으므로 이 약제내성은 R plasmid에 의한 것으로 생각되었다. 대다수의 균에 있어서 약제내성 전부를 E. coli에 전달하였으나, Na와 Rf의 내성은 전달되지 않았다. 일부 균주의 약제내성은 E. coli에 전달될 때 분리되는 일이 있었으나, 그 수는 극히 적었다. Shigella의 R Plasmid는 대부분이 비적합성군(incompatibility group) F II에 분류되었으나, 극소수는 B군에 속하였고 군별이 안되는 것도 있었다.

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