• 환경위생공학
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• 제16권3호
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• pp.22-27
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• 2001

It have been investigated how algal and bacterial symbiotic reaction influences on removal of organic carbon in river ecosystem. And artificial experimentation apparatus was made for algae'and bacteia'culture as lab scale. Investigating and researching minutely the change of concentration of organic carbon substrate and the change of population density of algae'and of bacteria'with this artificial experimentation apparatus, the next results could be obtained. 1. Successful decrease of DOC(dissolved organic carbon) could not be expected unless algal and bacterial biomass floe was nut formed effectively and unless biosorption was not proceeded effectively in the very culture system in which artificial synthetic wastewater was supplied continuously at constant rate. 2. In conditions of culture liquid of 1335 glucnse mg/L(type 1) and of 267 glucose mg:L(type 2), the algal dominant species was always Chlorella vulgaris in both types in which artificial synthetic wastewater were supplied continuously at constant rate and algae population density was around maximum 107 cells/mL. 3. It was around 108 ~ 107 cells/mL that the population density of heterotrophic bacterium. In culture medium systems type 1 and type 2 in which artificial wastewater were supplied continuously at constant rate, the same density appeared initially when using the population density of Escherichia coli w 3110 as indirect indicator. And this density decreased rapidly till the culturing date 35 days were passed away, while this density increased with gentle slope after same date and then the trend of change at type 2 was more severe than one at type 1. 4. When seeing such a change of population density of Escherichia coli w 3110, the growth of heterotrophic bacterium appeared as survival instinct pattern of broader requirement of nutrient at condition of low concentration of organic carbon substrate than condition of high concentration of same substrate.

• 한국어병학회지
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• 제22권3호
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• pp.239-251
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• 2009

배양 온도, 배양 배지 중의 pH, NaCl 농도, iron 농도와 같은 배양 조건이 P. damselae의 미생물학적 성상 및 병원성에 미치는 영향을 조사하였다. P. damselae는 배양 온도 15-30${^{\circ}C}$에서 배지의 pH 5-9, NaCl 농도 0-6%와 $FeCl_{3}$ 첨가시 성장이 촉진되었지만, iron-chelator 첨가 시성장이 억제되었다. Iron-limited 조건에서 배양시 ECPs protein 농도, phospholipase, 용혈능, siderophore 및 cytotoxicity 활성 이 높게 나타났고, 넙치 혈청의 살균작용 대한 생존율도 증가 되었으나, iron-added 조건에서는 감소되어, 배양 조건 중 iron 농도에 영향을 가장 많이 받는 것으로 나타났다. 따라서, 본 연구에서 적용한 iron-limited 조건은 철농도가 낮은 숙주 내와 유사한 환경이므로 iron-limited에서 P. damselae 배양 시 나타나는 병원성의 증가는 어체에 감염시 나타나는 병원성 발현 기전과 유사할 것으로 사료된다.

• Animal Bioscience
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• 제36권1호
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• pp.63-74
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• 2023

Objective: The objective of this study was to investigate the effects of feeding active dry yeast (ADY) and yeast culture (YC) on fecal bacterial community in finishing bulls fed high-concentrate diets in the same experimental environment. Methods: Forty-five healthy finishing cattle (Simmental×Chinese Luxi yellow bulls; 24 months; 505±29 kg) were randomly divided into three groups: i) CON group (control group, only fed basal diet), ii) ADY group (fed basal diet + active dry yeast), and iii) YC group (fed basal diet + yeast culture). At the end of the trial, nine rectum fecal samples were randomly selected from each group for bacterial DNA sequencing. Results: There was no difference among groups about alpha diversity indices (all p>0.05), including ACE, Chao 1, Shannon, and Simpson indices. Principal component analysis and non-metric multidimensional scaling analysis showed a high similarity among three groups. Compared with CON group, ADY and YC groups had greater relative abundance of c_Clostridia, o_Oscillospirales, and f_Oscillospiraceae, but lesser relative abundance of g_Megasphaera, and s_Megasphaera_elsdenii (all p<0.01). And, the relative abundances of p_Firmicutes (p = 0.03), s_Prevotella_sp (p = 0.03), o_Clostridiales (p<0.01), g_Clostridium (p<0.01), f_Caloramatoraceae (p<0.01), and f_Ruminococcaceae (p = 0.04) were increased in the ADY group. The PICRUSt2 prediction results showed that the metabolic pathways had no significant differences among groups (p>0.05). Besides, the relative abundance of c_Clostridia (r = 0.42), and f_Oscillospiraceae (r = 0.40) were positively correlated to average daily gain of finishing bulls (p<0.05). Conclusion: Both of ADY and YC had no effect on diversity of fecal bacteria in finishing bulls, but the supplementation of ADY and YC can improve the large intestinal function in finishing bulls by increasing the abundance of cellulolytic bacteria and altering the abundance of lactic acid-utilizing bacteria.

• Asian-Australasian Journal of Animal Sciences
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• 제18권4호
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• pp.512-515
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• 2005

An in vitro study was conducted to determine the effect of C18-polyunsaturated fatty acid on direct incorporation into the rumen bacteria, bio-hydrogenation and production of CLA in vitro. Sixty milligrams of linoleic acid ($C_{18:2}$) or linolenic acid ($C_{18:3}$) were absorbed into the 0.5 g cellulose powder was added to the 150 ml culture solution consisting of 120 ml McDougall's buffer and 30 ml strained rumen fluid. Four uCi of 1-$^{14}C_{18:2}$ or 1-$^{14}C_{18:3}$ (1 uCi/15 mg each fatty acid) were also added to the corresponding fatty acids to estimate the direct incorporation into the bacterial lipids. The culture solution was then incubated anaerobically in a culture jar with stirrer at 39$^{\circ}C$ for 12 h. Ammonia concentration and pH of the culture solution were slightly influenced by the fatty acids. Amount of fatty acid incorporated into the bacteria was 1.20 mg and 0.43 mg/30 ml rumen fluid for $C_{18:2}$ and $C_{18:3}$, respectively during 12 h incubation. Slightly increased CLA (sum of cis-9, trans-11 and cis-10, trans-12 $C_{18:2}$) was obtained from the $C_{18:3}$ addition compared to that from $C_{18:2}$ after 12 h incubation in vitro.

• KSBB Journal
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• 제13권2호
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• pp.209-213
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• 1998

The characteristics of de-emulsification of pertroleum emulsion by Nocardia amarae were investigated. Insoluble medium containing n-hexadecane was more effective than soluble medium in de-emulsification of emulsion containing diesel and bunker C as the organic phase. Emulsion made by the addition of xanthan or bioemulsifier was de-emulsified by N. amarae, and longer culture age was effective. In low viscosity range, organic phase with longer carbon chain was more effective. The contact, angle between bacterial film and water droplet in air increased from 16 degree for 4 day culture age to 26 degree for 15 day. The contact angle between bacterial film and water droplet in kerosene, n-heyxane or n-hexadecane also increased to greater than 100 degree after 3 day culture age. The hydrophobicity of bactgerial film increased according to the culture age.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1424-1433
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• 2019

DDT is a hydrophobic organic pollutant, which can be bio-accumulated in nature and have adverse consequences on the physical condition of humans and animals. This study investigated the relationship between the white-rot fungus Pleurotus eryngii and biosurfactant-producing bacterium Ralstonia pickettii associated with the degradation of DDT. The effects of R. pickettii on fungal development were examined using in vitro confrontation assay on a potato dextrose agar (PDA) medium. R. pickettii culture was added to the P. eryngii culture at 1, 3, 5, 7, and 10 ml ($1ml{\approx}1.44{\times}10^{13}CFU$). After 7 d incubation, about 43% of the initial DDT ($12.5{\mu}M$) was degraded by the P. eryngii culture only. The augmentation of 7 ml of R. pickettii culture revealed a more highly optimized synergism with DDT degradation being approximately 78% and the ratio of optimization 1.06. According to the confrontational assay, R. pickettii promoted the growth of P. eryngii towards the bacterial colony, with no direct contact between the bacterial cells and mycelium (0.71 cm/day). DDD (1,1-dichloro-2,2-bis(4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene), and DDMU (1-chloro-2,2-bis(4-chlorophenyl) ethylene) were identified as metabolic products, indicating that the R. pickettii could enhance the DDT biodegradation by P. eryngii.

• 생명과학회지
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• 제8권6호
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• pp.711-722
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• 1998

본 연구는 혈액에서 분리되는 세균의 항균제 감수성 양상을 파악하기 위하여 1993년 10월 1일부터 1996년 9월 30일 사이에 K대학 부속병원의 입원 및 외래환자 13,595명을 대상으로 혈액배양에서 분리된 1,104균주중 716균주를 세균의 균종별, 연령별, 계절별 분리빈도와 항균제 감수성 검사를 실시하여 다음과 같은 결과를 얻었다. 1. 최근 3년간 균분리 양성은 1,104명으로 8.1%의 양성률을 보였다. 연구대상 716균주의 균종별 분리빈도는 E. coli가 29.8% (213주)로 분리율이 가장 높았다. 2. 대부분의 균종은 50세, 60세군 및 2세 이하군에서 분리율이 높았고, S. typhi는 30세군에서 분리율이 높았다. 3. 계절별 분리율은 대부분의 균종이 여름철에 분리율이 높았고, E. coli는 계절에 관계없이 분리되었다. 4. 항균제 감수성은 그람양성 구균의 경우 penicillin계 항균제인penicillin-G에 E. faecalis를 제외한 균에서 높은 내성률을 보였으며, vancomycin과 teicoplanin에는 감수성이 높았다. 그람음성 간균은 amikacin, ciprofloxacin, 및 imipenem에는 감수성이 높았고, ampicillin에는 내성을 보였다. S. typhi는 cephalothin을 제외한 모든 항균제에 100%의 감수성이었다. 이상의 결과에서 균혈증 환자로부터 분리된 세균에는 penicillin계 항균제에 내성인 균주가 많으며 glycopeptide계 항균제와 amikacin, ciprofloxacin 및 imipenem에는 아직 내성이 낮다는 결론을 얻었다.

• 대한가정학회지
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• 제42권3호
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• pp.145-158
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• 2004

Experimental conditions for evaluating chitosan antibacterial activities were established. The chitosan antibacterial activities were measured against the Staphylococcus aureus and evaluated for their application to antibacterial textile finishing. The strain of Staphylococcus aureus used in this experiments was KCTC 1916. The chitosan antibacterial activities were estimated from the bacterial densities or ％reduction of bacteria in chitosan solutions and bacterial culture mixtures after incubation under specific conditions. Six parameters as follows were evaluated to optimize the experimental conditions for measuring antibacterial activities. The different combinations of mixtures according to the different ratios of chitosan solutions to the bacterial cultures showed different antibacterial activities. However, the chitosan antibacterial activities could be evaluated by comparing the data obtained from the same combinations of mixtures. The solvent influence on the chitosan solution antibacterial activities could be eliminated using control solution containing the same concentration of acetic acid. The initial pH of the chitosan -bacterial mixtures also affected the chitosan antibacterial activity; at a higher pH, higher activity in terms of ％reduction of bacteria was observed. In case of the bacterial solution without either the acetic acid or chitosan, the initial pH of the solution did not significantly affect bacterial growth. The ％ reduction of bacteria increased when contact times of bacteria with chitosan in the chitosan -bacterial mixture were expended upto 24 hours. However, the chitosan antibacterial activities could be successfully evaluated at contact time 0 where the chitosan-bacterial mixture was plated immediately after mixing and incubated to measure the bacterial number to 24 hours. Evaluating ％reduction of bacteria in the test mixtures after incubation were not changed when the inoculated bacterial concentrations were 2.3${\times}$10$\^$0/ml to 2.3${\times}$10$\^$6/ml. The optimal range of incubation time of the petri-Dish after plating the chitosan-bacterial mixture was 24 to 72 hours depending on the antibacterial activities of the test solutions.

• The Plant Pathology Journal
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• 제22권1호
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• pp.103-106
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• 2006

In this biocontrol research, we evaluated disease suppressive effects of antagonistic bacterial strains ISE13 and KJ1R5 against Korean ginseng root rot caused by P. eaetorum. We also examined the effects of nutrient solution in the hydroponic culture system for Korean ginseng on biological activity of the bacterial strains. As results of dual culture tests of the bacterial strains on $V_{8}$ juice agar, the strain ISE13 showed antifungal activity against P. eaetorum and other plant pathogenic fungi, but the strain KJ1R5 did not. When their inhibitory effects against infection of P. eaetorum on the roots grown in either nutrient solution or water were tested, the strains ISE13 and KJ1R5 inhibited the disease severity of Korean ginseng roots only grown with water, compared to buffer-treated, inoculated controls. However, the nutrient solution used for hydroponic cultures of ginseng in pots caused higher levels of disease severity by the strains ISE13 and KJ1R5 from 418.8\%$ to 40.0\%$ and from 24.3\%$ to 45.0\%$, respectively. In this study, the bacterial strains ISE13 and KJ1R5 could be potentially biocontrol agents to suppress Korean ginseng root rot caused by P. eaetorum. However, more attention using nutrient solution in hydroponic cultures for Korean ginseng production should be applied in biocontrol of plant diseases using the antagonistic microorganisms.

• Journal of Microbiology and Biotechnology
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• 제20권8호
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• pp.1230-1239
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• 2010

Five bacterial species, capable of degrading the recalcitrant organic compounds (ROCs) diethyleneglycol monomethylether (DGMME), 1-amino-2-propanol (APOL), 1-methyl-2-pyrrolidinone (NMP), diethyleneglycol monoethylether (DGMEE), tetraethyleneglycol (TEG), and tetrahydrothiophene 1,1-dioxide (sulfolane), were isolated from an enrichment culture. Cupriavidus sp. catabolized $93.5{\pm}1.7$ mg/l of TEG, $99.3{\pm}1.2$ mg/l of DGMME, $96.1{\pm}1.6$ mg/l of APOL, and $99.5{\pm}0.5$ mg/l of NMP in 3 days. Acineobacter sp. catabolized 100 mg/l of DGMME, $99.9{\pm}0.1$ mg/l of NMP, and 100 mg/l of DGMEE in 3 days. Pseudomonas sp.3 catabolized $95.7{\pm}1.2$ mg/l of APOL and $99.8{\pm}0.3$ mg/l of NMP. Paracoccus sp. catabolized $98.3{\pm}0.6$ mg/l of DGMME and $98.3{\pm}1.0$ mg/l of DGMEE in 3 days. A maximum $43{\pm}2.0$ mg/l of sulfolane was catabolized by Paracoccus sp. in 3 days. When a mixed culture composed of the five bacterial species was applied to real wastewater containing DGMME, APOL, NMP, DGMEE, or TEG, 92~99% of each individual ROC was catabolized within 3 days. However, at least 9 days were required for the complete mineralization of sulfolane. Bacterial community diversity, analyzed on the basis of the TGGE pattern of 16S rDNA extracted from viable cells, was found to be significantly reduced in a conventional bioreactor after 6 days of incubation. However, biodiversity was maintained after 12 days of incubation in an electrochemical bioreactor. In conclusion, the electrochemical reduction reaction enhanced the diversity of the bacterial community and actively catabolized sulfolane.