• Asian-Australasian Journal of Animal Sciences
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• 제22권2호
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• pp.238-245
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• 2009

Pure culture experiments were conducted to assess the bacteriostatic and bactericidal effects of phlorotannins (PT) isolated from Ascophyllum nodosum (brown seaweed) on Escherichia coli O157:H7. In Exp. 1, one non-O157:H7 strain (25922) and three strains of E. coli O157:H7 (3081, EDL933 and E318N) were cultured in M9 medium with PT included at 0 (control), 25, 50 or $100{\mu}g/ml$ (n = 3). Bacterial growth was monitored by $OD_{600}$ at 0, 4, 6, 12 and 24 h, and by dilution plating at 0, 4, 6 and 24 h. All strains were inhibited (p<0.001) by PT to varying degrees. At 50 or $100{\mu}g/ml$, PT prevented growth of all four strains. At $25{\mu}g\;PT/ml$, growth of 25922, 3081, E318N and EDL933 was inhibited for 6, 12 and 24 h, respectively, but 25922 and 3081 resumed growth by 12 and 24 h. Direct plating confirmed bactericidal effects of PT on all four strains at $100{\mu}g/ml$, and on EDL933 and E318N at $50{\mu}g/ml$. In Exp. 2, strains 25922 and 3081 were incubated with no tannins or with $50{\mu}g/ml$ of PT, purified condensed tannins (CT) from Quebracho (Schinopsis balansaei), or purified tannic acid from Rhus semialata (Anacardiaceae) as hydrolysable tannins (HT). Strain 3081 was unaffected by HT or CT, but was completely inhibited (p<0.001) by PT at 4, 6 and 24 h. Strain 25922 was unaffected by HT, slightly inhibited by CT, and almost eradicated by PT at 4 and 6 h. Transmission electron microscopy revealed tannin-mediated alterations to bacterial cell walls. Phlorotannins from A. nodosum exhibit growth-inhibiting and bactericidal effects in vitro against the strains of E. coli O157:H7 investigated. Anti-E. coli efficacy of A. nodosum PT is superior to that of terrestrial tannins purified from Quebracho and from Rhus semialata.

• 한국환경보건학회지
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• 제28권2호
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• pp.193-202
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• 2002

The polymerase chain reaction(PCR) of target lacZ and uidA genes were used to detect total coliform and Escherichia coli for determining water quality, respectively. Of 109 spring waters, coliform were detected from 38 spring waters by lacZ PCR method but 21 spring waters by culture method accepted by the Ministry of Environment for water quality monitoring. The lacz PCR method gave the results statistically equivalent to those of the culture method(kappa=0.62, McNemar=17.00). The uidA PCR method gave the same results to those of the culture method. The sensitivity and specificity of coliform and E. coli by PCR method were 100% and 80.7%, respectively. Therefore, PCR can be used for the rapid identification of Escherichia coli and coliform in potable water using uidA and lacZ.

• Journal of Animal Science and Technology
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• 제47권4호
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• pp.547-554
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• 2005

본 연구는 메주에서 순수 분리된 메주곰팡이의 대표적 균종인 황국균(Aspergillus oryzae; AO)으로 만든 AO culture와 Salmonella 병원특이 유전자를 삽입한 형질전환 AO(TAO) culture가 산란계의 생산성, 계란 품질 및 장내 미생물 균총에 미치는 영향을 규명하고자 실시하였다. 39주령 산란계 Hy-line Brown 840수를 공시하여 대조구, AO culture 0.2%와 0.5%, TAO culture 0.2%와 0.5%, UV를 조사하여 단백질 분해효소를 감소시킨 mutant에 Salmonella 병원 특이 유전자를 삽입한 형질전환 AO(TMAO) culture 0.2%와 0.5% 첨가구들을 비교하였다. 각 첨가구는 6반복, 반복당 20수씩, 한 케이지 당 2수씩 배치하여 8주간 사양시험을 실시하였다. 사양시험 결과 모든 산란 생산성 및 계란 품질 관련 조사항목에서 처리간에 유의한(P<0.05) 차이가 있었다. TAO culture 0.2% 첨가구가 산란 생산성에 있어서 유의적으로 가장 높았으며, 난중은 모든 AO 첨가구들이 대조구에 비해 유의적으로 낮거나 낮아지는 경향을 나타내었다. 연파란율은 TMAO culture 0.5% 첨가구가 가장 낮았다. 사료섭취량과 사료요구율은 대조구와 모든 AO 첨가구들간에 유의적 차이가 나타나지 않았다. 난각 강도는 대조구 보다 모든 AO 첨가구들에서 유의적으로 높게 나타났으며, 난황 색도는 TMAO culture 0.5% 첨가구에서 가장 높았다. 난각 색도와 Haugh unit은 대조구와 모든 AO 첨가구들간에 유의적 차이가 나타나지 않았다. 장내 미생물 균총(Salmo- nella spp., E. coli. Lactobacilli spp.)에서는 유의적(P<0.05) 차이가 있었다. AO culture 첨가에 의해서 Lactobacilli spp.의 수는 증가되고, E. coli 및 Salmonella spp.의 수는 감소되었다. 특히 TAO와 TMAO culture 첨가구에서는 AO culture 첨가구보다 Salmonella spp. 및 E. coli 억제효과가 컸으며 첨가수준(0.5% vs 0.2%) 간에는 유의한 차이가 없었다. 결론적으로 TAO culture 0.2% 첨가는 산란 생산성 증가에 효과가 있었으며 TAO 및 TMAO culture 0.2% 첨가는 장내 E. coli 및 Salmonella spp.의 감소에 유의한 효과가 있었다.

• 한국미생물·생명공학회지
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• 제23권6호
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• pp.665-670
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• 1995

A marine bacterium which produces extracelluar agarase was isolated from sea water. Isolated strain was identified as Pseudomonas sp. by the morphological and biochemical properties (1). HindIII restriction fragment of 3.2 kb from Pseudomonas genomic DNA was cloned into pUC19 to obtain recombinant plasmid pJA1 which enables E. coli JM83 to produce agarase. Most of agarase produced in E. coli was secreted into the culture medium. The enzyme (pJA1) showed the highest agarase activity during the stationary phase (20 hrs) of E. coli. The optimum temperature and pH were 40$\circ$C and 7.8, respectively. Restriction gene map anlaysis revealed that it has different restriction pattern with three kind of agarase gene reported.

• Journal of Microbiology and Biotechnology
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• 제6권6호
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• pp.451-455
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• 1996

Physiological studies on the expression of Bacillus thuringiensis subsp. tenebrionis (Btt) gene coding for insecticidal protein in recombinant Escherichia coli 537 were carried out to identify optimal culture condition. It was necessary to shift culture temperature from 30 to $42^{\circ}C$ to express the gene. Expression of the Btt toxin gene by recombinant E. coli 537 began within one hour after induction. Complex nitrogen sources increased production of the insecticidal protein. The total insecticidal protein was 0.5 g/I when using yeast extract as a complex nitrogen source. Soybean hydrolysate showed apparently the highest induction efficiency. After induction, the cellular content of the insecticidal protein was 5.4 times higher than it had been before induction. The optimal cultivation strategy was found to grow cells for 7hours at $30^{\circ}C$ and then 5-8 hours at $42^{\circ}C$. The optimal cultivation pH for the production of insecticidal protein was 6.5. The Btt toxin produced by the recombinant E. coli 537 was found to have the same level of potency against Colorado potato beetle as the original toxin.

• Journal of Microbiology
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• 제38권1호
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• pp.36-39
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• 2000

Toxic hexavalent chromium, Cr(VI), was reduced to a less toxic trivalent chromium form by E. coli ATCC 33456. The suitable electron donor for Cr(VI) reduction was glucose. E. coli ATCC 33456 was more resistant to metal cations than other reported Cr(VI) reducing microorganisms. Cell growth was inhibited by the presence of Cr(VI) in a liquid medium and Cr(VI) reduction accompanied cell growth. With a hydraulic retention time of 20 h, Cr(VI) reducing efficiency was 100% to 84% when Cr(VI) concentration in the influent was in the range of 10 to 40 mg L$\^$-1/. Specific rate of Cr(VI) reduction was 2.41 mg Cr(VI) g DCW$\^$-1/ h$\^$-1/ when 40 mg L$\^$-1/ of Cr(VI) influent was used. This result suggested the potential application of E. coli ATCC 33456 for the detoxification of Cr(VI) in Cr(VI) contaminated wastewater.

• 한국미생물·생명공학회지
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• 제24권5호
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• pp.619-623
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• 1996

Some physical and physiological properties of di-D-fructofuranose dianhydrideIII (DFAIII), as a new sweetener, were investigated via in vitro experiments. The disaccharide was prepared by decomposing inulin with inulin fructotransferase (depolymerizing) from Arthrobacter sp. A-6. DFAIII had more excellent heat and acid stability than sucrose. This was one of the most desirable properties especially for the oligomer types of sweetener. DFAIII showed the least pH drop in the Streptococcus mutans culture, compared with the other saccharides examined. This indicates that the sugar will be fairly effective for preventing dental caries. The saccharide also had a selective Bifidus growth-promoting effect in PYF medium. Whereas, E. coli did not show growth promotion in the DFAIII-containing medium. In the co-culture of Bifidus longum and E. coli in the BL medium, Bifidus longum had a selective growth while the growth of E. coli appeared rather to be inhibited.

• Journal of Microbiology and Biotechnology
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• 제5권2호
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• pp.68-73
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• 1995

Pseudomonas sp. P20 was shown to be capable of degrading biphenyl and 4-chlorobiphenyl (4CB) to produce the corresponding benzoic acids wnich were not further degraded. But the potential of the strain for biodegradation of 4CB was shown to be excellent. The pcbA, B, C and D genes responsible for the aromatic ring-cleavage of biphenyl and 4CB degradation were cloned from the chromosomal DNA of the strain. In this study, the pebC and D genes specifying degradation of 2, 3-dihydroxybiphenyl (2, 3-DHBP) produced from biphenyl by the pebAB-encoded enzymes were cloned by using pBluescript SK(＋) as a vector. From the pCK102 (9.3 kb) containing pebC and D genes, pCK1022 inserted with a EcoRI-HindIII DNA fragment (4.1 kb) carrying pebC and D and a pCK1092 inserted with EcoRI-XbaI fragment (1.95 kb) carrying pebC were constructed. The expression of pcbC and D' in E. coli CK102 and pebC in E. coli CK1092 was examined by gas chromatography and UV-vis spectrophotometry. 2.3-dihydroxybiphenyl was readily degraded to produce meta-cleavage product (MCP) by E. coli CK102 after incubation for 10 min, and then only benzoic acid(BA) was detected in the 24-h old culture. The MCP was detected in E. coli CK1022 containing pebC and 0 genes (by the resting cells assay) for up to 3 h after incubation and then diminished completely in 8 h, whereas the MCP accumulated in the E. coli CK1092 culture even after 6 h of incubation. The 2, 3-DHBP dioxygenases (product of pebC gene) produced by E. coli CK1, CK102, CK1023, and CK1092 strains were measured by native PAGE analysis to be about 250 kDa in molecular weight, which were about same as those of Pseudomonas sp. DJ-12, P. pseudoa1caligenes KF707, and P. putida OU83.

• 한국동물위생학회지
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• 제42권2호
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• pp.93-112
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• 2019

Calf diarrhea is a common disease in young claves and is still a major cause of productivity and economic loss in livestock farms. Fecal samples from Korean native cattle (n=100) with diarrhea from 64 farms in Gwangju area, Korea from september 2017 to December 2018 were examined for shedding of important protozoan parasitic, viral and bacterial pathogens using culture, rapid test kit and PCR methods. Of 57 (89.1%) of the 64 Korean native cattle farms examined had samples infected with at least one of the investigated pathogens. Among 100 fecal samples, 88 samples were positive for at least one the twelve pathogens and 51 samples were simultaneously positive for two or more pathogens by culture and PCR assay. Bovine group A rotavirus (BRV) was the most common pathogen, found in 43/100 (43.0%) samples on 32/64 (50.0%) farms. Subsequently, kobuvirus (30.0%), pathogenic E. coli (29.0%), bovine parvovirus (17.0%), Giardia spp. (13.0%), Eimeria spp. (10.0%), Clostridium perfringens type A (8.0%), bovine torovirus (8.0%), bovine viral diarrhea virus (6.0%), bovine coronavirus (5.0%), bovine norovirus (2.0%) and Cryptosporidium spp. (2.0%) were detected. Nebovirus, kırklareli virus, bovine adenovirus, Salmonella spp. and intestinal parasites were not detected. Of the 72 calves sampled in this age group, 64 (88.9%) samples were positive for at least one enteropathogen. BRV was identified in 34/72 (47.2%) samples from 27/48 (56.3%) farms. Subsequently, pathogenic E. coli (30.6%), kobuvirus (29.2%), BPaV (22.2%), Giardia spp. (15.3%), Eimeria spp. (9.7%), BVDV (6.9%), Cl. perfringens type A (6.9%), BCoV (4.6%) and Cryptosporidium spp. (2.8%) were detected in fecal samples. A total of ninety-six strains of E. coli were isolated from one hundred fecal samples collected from Korean native cattle with diarrhea. The presence of stx1, stx2, eaeA, LT, STa, STb, ehxA, saa, F4, F5(K99), F6, F17, F18 and F41 genes in the isolates was investigated by PCR. Out of ninety-six E. coli isolates screened for specific genes, 30 strains E. coli were identified to harbor shiga toxin-producing E. coli (STEC) 7 (7.3%), enterohemorrhagic E. coli (EHEC) 8 (8.3%), enteropathogenic E. coli (EPEC) 6 (6.3%), enterotoxigenic E. coli (ETEC) 2 (2.1%) and STEC/ETEC hybrid 7 (7.3%). This study provides epidemiological estimates of the prevalence of Korean native cattle's enteropathogens in Gwangju area, Korea, which would be used for cattle farmers and veterinarians to select appropriate therapeutic method.

• 공업화학
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• 제25권4호
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• pp.386-391
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• 2014

본 연구에서는 상압 저온 코로나 방전 플라즈마를 화산암재(스코리아) 분말의 살균에 적용하였다. 스코리아 분말에 Escherichia coli (E. coli) 배양액을 살포하여 균일하게 혼합한 후, 코로나 방전 플라즈마 특성 인자인 방전전력, 방전시간, 주입기체, 전극간격 등의 조건을 변화시키며 E. coli 살균효율을 조사하였다. 실험 결과 상압 저온 코로나 방전 플라즈마는 분말상의 스코리아 살균에 아주 효과적인 것으로 나타났으며, 방전전력 15 W에서 5 min 동안 살균한 결과 E. coli가 99.9% 이상 사멸하였다. 방전전력, 방전시간, 인가전압이 증가할수록 사멸율이 향상되었다. 반응기에 주입되는 기체의 종류에 따른 살균력 실험 결과, 산소 > 모사공기(산소 20%) > 질소 순으로 나타났다. 코로나 방전 플라즈마에 의한 E. coli 살균은 자외선과 활성산화종(산소라디칼, OH라디칼, 오존 등)에 의한 세포막 침식 및 에칭, 그리고 플라즈마 방전 스트리머에 의한 대장균 세포막 파괴로 설명할 수 있다.