• 미생물학회지
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• 제40권2호
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• pp.127-132
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• 2004

활성 오니법에 의한 하수처리장 포기조에서 슬러지를 채취하여 황화물계 악취제거 균주인 Thiobacillus속의 선별 배지로 50개 균주를 분리하였다. 분리한 50개 균주의 동정 결과 7개 균주는 Thiobaecillus neapolitanus, 4개 균주는 Thiobacillus tepidarius, 5개 균주는 Thiobacillus denitrificans, 23개 균주는 Thiobacillus versutus, 2개 균주는 Thiobacillus intetmedius, 9개 균주는 Thiobacillus perometabolis로 동정되었다. 분리 동정한 균주들로 고효율 황화물계 악취(황화수소, dimethyl sulfide, methyl disulfide)제거 균주 스크린을 하였다. 그 결과 황화수소, dimethyl sulfide에 대하여 KT5l(Thiobacillus versutus)균주가 각각 l00％, 85％로 가장 높은 제거율을 보였다. Dimethyl disulfide의 경우에는 전체 균주가 다른 악취성분에 비해 제거율이 낮았는데 KT8l균주가 26％로 가장 높은 제거율을 보였다. 스크린 결과 KT5l균주를 선별하였으며, 선별된 KT51균주를 밀폐된 모형 생물학적 처리 반응기에 적용하여 황 화합물의 제거 효율을 비교한 결과, 황화수소의 경우, 100 ppm을 주입 후 균주 적용전의 운전 결과는 30분 이후에 0.02 ppm 미만(99.8％)으로 제거한 반면, 균주 적용 시의 운전 결과는 15분에 황화수소를 0.02 ppm 미만(99.8％)으로 처리하였다.

• BMB Reports
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• 제39권4호
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• pp.383-393
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• 2006

Little is known concerning the mechanisms responsible for the transplacental transfer of thiamine. So, the aim of this work was to characterize the placental uptake of thiamine from the maternal circulation, by determining the characteristics of $^3H$-thiamine uptake by a human trophoblast cell line (BeWo). Uptake of $^3H$-thiamine (50-100 nM) by BeWo cells was: 1) temperature-dependent and energy-independent; 2) pH-dependent (uptake increased as the extracellular medium pH decreased); 3) $Na^+$-dependent and $Cl^-$-independent; 4) not inhibited by the thiamine structural analogs amprolium, oxythiamine and thiamine pyrophosphate; 5) inhibited by the unrelated organic cations guanidine, N-methylnicotinamide, tetraethylammonium, clonidine and cimetidine; 6) inhibited by the organic cation serotonin, and by two selective inhibitors of the serotonin plasmalemmal transporter (hSERT), fluoxetine and desipramine. We conclude that $^3H$-thiamine uptake by BeWo cells seems to occur through a process distinct from thiamine transporter-1 (hThTr-1) and thiamine transporter-2 (hThTr-2). Rather, it seems to involve hSERT. Moreover, chronic (48 h) exposure of cells to caffeine ($1\;{\mu}M$) stimulated and chronic exposure to xanthohumol and iso-xanthohumol (1 and $0.1\;{\mu}M$, respectively) inhibited $^3H$-thiamine uptake, these effects being not mediated through modulation of the expression levels of either hThTr-1 or hSERT mRNA.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.772-779
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• 2005

Ammonia-oxidizing bacteria (AOB) were enriched by repeating fed-batch cultivations in an AOB-selective medium of activated sludges from a domestic wastewater treatment plant. Enriched culture showed strong capabilities of ammonia oxidation [0.810 mg $NH_4^+$-N/mg mixed liquor suspended solids (MLSS)$\cdot$day] as well as $NO_x^-$-N production (0.617 mg $NO_x^-$-N/ mg MLSS$\cdot$day). Degree of enrichment was examined through fluorescent in situ hybridization (FISH) analyses using an AOB-specific Cy3-labeled oligonucleotide probe (NSOl90) and terminal-restriction fragment length polymorphism (T-RFLP) analyses. FISH analyses confirmed that the fraction of AOB among 4',6-diamidino-2-phenylindole (DAPI)-stained cells increased from about less than $0.001\%$ to approximately $42\%$ after enrichment of AOB, and T-RFLP analyses showed that bacterial community became simpler as enrichment was continued. When the enriched culture of AOB was added (150 mg/l as dry suspended solid) to the normal activated sludge (3,000 mg/l as dry suspended solid), nitrification efficiencies were improved from 0.020 mg $NO_x^-$-N/mg MLSS$\cdot$day to 0.041 mg $NO_x^-$-N/mg MLSS$\cdot$day in a synthetic wastewater and also from 0.0007 mg $NO_x^-$-N/mg MLSS$\cdot$day to 0.0918 mg $NO_x^-$-N/mg MLSS$\cdot$day in a real domestic wastewater. Therefore, it is expected that this enrichment method could be used for improving efficiency of nitrification in wastewater treatment plants.

• 한국미생물·생명공학회지
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• 제32권3호
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• pp.224-229
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• 2004

토양으로부터 강력한 CAH activity를 갖는 균주를 분리하여, 생화학적, 배양학적, 전자현미경 동정을 한 결과, Bacillus sphaericus로 확인되었으며, 이를 B. sphaericus 366M-9로 명명하였다. 또한 이 균으로부터 최초로 cephalosporin-C deacetylase(CAH)를 분리 정제하였다. 정제수율은 약 7.5% 였으며, B. sphaericus 366M-9에서 분리한 CAH-9의 최적활성 온도는 $50^{\circ}C$였으며, 효소안정 온도구간은 30～$50^{\circ}C$이다. 또한 최적 활성 pH는 7.0이었으며, 효소안정 pH구간은 pH 6.0～8.0으로 90% 이상의 잔존 활성도를 나타내었다. 효소반응속도에 미치는 기질의 영향에서는 $K_{m}$ 값은 0.87 mM 이며,$ V_{max}$는1.22 unit/ml이었다.다.

• 한국식품과학회지
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• 제31권5호
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• pp.1357-1362
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• 1999

한국인의 장내세균중의 유해효소생성 균주를 분리하여 장내환경 개선연구에 활용하고자 ${\beta}-glucuronidase$와 $7{\alpha}-dehydroxylase$의 유해효소를 분비하는 장내세균으로 알려진 Clostridium속 균주를 분리하였다. 동일인의 장내세균을 2회에 걸쳐서 검색한 후 최다 우점종이외의 장내세균은 동일인이라도 식이등 외부환경에 의하여 변화될 수 있음을 알았다. 이어서 Neomycin-Nagler 선택배지를 사용하여 Clostridium spp.를 14종 분리하여 이들 균주가 유해효소를 생산하는지를 조사하였다. 일차 선발균주중 Clostridium sp. Isolate-11은 ${\beta}-glucuronidase$를 강력히 생성하여 0.021 unit/mg protein의 활성을 보여주었으나 이들 분리 균주중에서 $7{\alpha}-dehydroxylase$의 역가를 TLC상에서 검출할 수 있는 균주는 발견하지 못했다. Isolate-11를 배양생리학적으로 동정한 결과 이 균은 Clostridium scatologenes인 것으로 잠정동정하였다.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.222-228
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• 2001

Vibrio metschnikovii strain RH530 is a non-pathogenic, industrially-important alkaline protease producer which has been isolated from wastewater. In this paper, we report on the transformation of this strain by using the method of electroporation. A field strength of $7.5\;kVcm^{-1}$ and $25\;{\mu}F$, and using a 0.2-cm cuvette, appeared to be the optimal conditions for electroporation of the cells with the recombinant pSBCm plasmid carrying the vapK alkaline protease gene and the ColE1 replicon. Cells were subjected to osmotic shock in order to remove extracelluar DNase, and adding 200 mM of sucrose to electroporation buffer cells showed an increased transformation efficiency. Maximum efficiency of transformation was obtained at an early exponential growth phase. Using all of the conditions mentioned above, we routinely obtained a transformation efficiency of more than $10^4{({\mu}g\;plasmid\;DNA)}^{-1}$. The stability of the plasmid pSBCm in V. metschnikovii RH530 was 25% after 18h of growth (27 generations) in the medium without antibiotic selection. The insertion of the par locus to the pSBCm increased the stability of the plasmid up to 42% without selective pressure. The increase in plasmid stability was accompanied by the increase in the productivity of alkaline protease in the recombinant V. metschnikovii strain RH530. Determining optimal conditions for the transformation of the industrially-important, nonpathogenic Vibrio strain, and the improvement of plasmid stability by introducing the par locus into the high copy number plasmid vector, will allow the development of procedures involved in the genetic manipulation of this strain, particularly for its use in the production of industrial enzymes such as alkaline protease.

• Asian-Australasian Journal of Animal Sciences
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• 제14권1호
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• pp.48-53
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• 2001

An in vitro study was conducted to examine the effect of sources and the addition levels of carbohydrates on fermentation characteristics, bacterial growth, and hydrogenation of linoleic acid ($C_{18:2}$) by mixed ruminal bacteria. Starch and cellobiose were added to the 200 ml non-selective basal media at the levels of 0.20 and 0.35% (w/v), respectively. Linoleic acid (66.8~79.6 mg) in the absorbed form into the pieces of nylon cloth was also added to the media of 5 treatments including control which was not added with carbohydrate. Three mls of rumen fluid strained through 12 layers of cheese cloth were added to each medium, and were incubated anaerobically in the shaking incubator of $39^{\circ}C$ for 24 hours. During 24 h incubation the pH in incubation media of all treatments was maintained above 6.6 by the addition of sodium bicarbonate. The pH and ammonia concentration of incubation media were not clearly influenced by the sources and addition levels of carbohydrates while additions of carbohydrates increased (p<0.0001) VFA concentration at the 24 h incubation. Molar proportions of acetate were reduced (p<0.0004) while those of propionate were increased (p<0.0006) by the addition of carbohydrates. But the differences in concentration and molar proportions of the VFA were small between the sources or the addition levels. Bacterial growth was faster (p<0.0004) in the starch added treatments than in the cellobiose added ones and control, but no differences were found between addition levels. Increased (p<0.0487) hydrogenation was observed from the starch added treatments compared to the cellobiose added ones, but there was no difference between addition levels.

• The Korean Journal of Pain
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• 제11권2호
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• pp.307-310
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• 1998

Selective lumbosacral radiculography and nerve root block techniques are very useful in determining the nerve root involved. We have done the lumbar root block to 61-year-old female who had suffered from low back pain radiating to right lower leg which was not relieved by epidural steroid injection two times. $L_5$ root block was performed under the fluoroscopic C-arm guide. When the needle was in correct position, we injected contrast medium (Isovist$^{(R)}$ - 300, Schering, Germany). After we injected 1.5 cc isovist, the S1 root was figured but L5 root was not figured. When we reinjected 1.5 cc isovist, $S_1$ root was enhanced and $L_5$ root was slightly visible due to severe disc bulging and lateral spinal stenosis.

• Journal of Microbiology and Biotechnology
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• 제28권11호
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• pp.1846-1849
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• 2018

Recent human gut microbiome studies have supported that the genus Bifidobacterium is one of the most beneficial bacteria for human intestinal health. To develop a new probiotic strain for functional food applications, fourteen fecal samples were collected from healthy Koreans and the strain BCBR-583 was newly selected and isolated from a 25-year-old Korean woman's fecal sample using the selective medium for Bifidobacterium. Subsequent fructose-6-phosphate phosphoketolase (F6PPK) test and 16S rRNA gene sequencing analysis of the strain BCBR-583 confirmed that it belongs to B. longum subsp. longum. The stress resistance tests showed that it has oxygen and heat tolerance activities (5- and 3.9-fold increase for 24 h at 60 and 120 rpm, respectively; $78.61{\pm}6.67%$ survival rate at $45^{\circ}C$ for 24 h). In addition, gut environment adaptation tests revealed that this strain may be well-adapted in the gut habitat, with gastric acid/bile salt resistance ($85.79{\pm}1.53%$, survival rate under 6 h treatments of gastric acid and bile salt) and mucin adhesion ($73.72{\pm}7.36%$). Furthermore, additional tests including cholesterol lowering assay showed that it can reduce $86.31{\pm}1.85%$ of cholesterol. Based on these results, B. longum BCBR-583 has various stress resistance for survival during food processing and environmental adaptation activities for dominant survival in the gut, suggesting that it could be a good candidate for fermented food applications as a new probiotic strain.

• 유기물자원화
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• 제11권4호
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• pp.49-56
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• 2003

토양미생물인 Ralstonia eutropha JMP134는 세균의 염색체상의 페놀분해경로를 통하여 삼염화에틸렌(TCE)을 분해하는 특징이 있다. 이전의 실험에서 본 세균으로부터 분리된 페놀분해효소가 단독으로 삼염화에틸렌을 분해하는 것을 밝힌바 있다. 본 실험에서는 페놀분해효소를 생성하는 유전자를 유전자 재조합방법을 통하여 plasmid에 cloning한 유전자 재조합세균 R. eutropha AEK301을 대상으로 TCE의 분해능을 실험하였다. AEK301은 페놀에 의한 유도작용 없이도 여러 유기물의 존재하에서 TCE를 분해하는 것으로 나타났다. 본 세균은 0.05%의 에탄올이 유일한 탄소원으로 제공된 배양액에서 TCE의 농도 $200{\mu}M$ 까지 거의 분해하였으며 농도 $400{\mu}M$에서는 약 70%까지 제거하는 특성을 보여주었다.