• 대한수의학회지
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• 제52권3호
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• pp.169-176
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• 2012

Probiotics colonize the intestines and exert an antibacterial effect on pathogens. Therefore, probiotics could be used as a preventive agent against lethal infections. To isolate probiotic microorganisms, 116 bacterial strains were isolated from healthy cow's milk and were subjected to Gram-stain, morphology and biochemical analyses, Vitek analysis, and 16S rRNA analysis. One of the strains identified as Bacillus (B.) thuringiensis 87 was found to grow very well at pH 4.0~7.0 and to be resistant to high concentrations of bile salts (0.3~0.9% w/v). B. thuringiensis was susceptible to the antibiotics used in the treatment of bovine mastitis, yet it exhibited an antimicrobial effect against Staphylococcus (S.) aureus 305. Moreover, it protected mice from experimental lethal infections of E. coli O55, Salmonella typhimurium 01D, and S. aureus 305 through a significant induction of interferon-${\gamma}$, even at four-week post-administration of B. thuringiensis. Although oral administration of B. thuringiensis 87 did not provide significant protection against these lethal challenges, these results suggest that B. thuringiensis 87 could be a feasible candidate as a probiotic strain.

• 한국환경농학회지
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• 제20권1호
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• pp.57-62
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• 2001

여러 작물 재배지 토양에서 각종 근권미생물을 분리하여 이들 분리미생물 중 수박 만할병균인 Fusarium oxysporum f. sp. niveum(KCCM34741)에 길항하는 미생물인 YJ-19, YJ-45, YJ-3 등 12 균주를 분리하였다. 길항미생물들은 MS agar 배지 실험 및 미생물제제 첨가 상토 실험에서 모두 참박의 발아율을 향상시켰으며, 이들 중 분리주 YJ-3 균주는 참박의 발아율과 초기생육에 가장 큰 영향을 주는 미생물로 선별되었다. YJ-3 균주를 제제화하여 참박 재배 기간별로 식물체 생육실험을 행한 결과 대조구인 일반 상토 및 시판 미생물혼합 상토 보다 각각 46%와 13%정도 생육을 촉진하는 것으로 나타났다. 분리주 YJ-3 균주는 간균의 gram 양성균으로서 Bacillus sp.로 동정되었다. Bacillus sp. YJ-3은 수박 만할병균인 F. oxysporum f. sp. niveum에 대해 강한 억제효과를 나타내었고, 그외 수박 병원균인 Alternaria cucumerina, Botrytis cinerea, Colletotrichum orbiculare, Didymella bryoniae, Rhazoctonia solani 등에서도 우수한 길항력을 나타내어 본 Bacillus sp. YJ-3 균주는 수박 만할병균에 길항하는 동시에 참박의 생육을 촉진하는 미생물로 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.646-651
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• 2005

The growth responses of Ruta chalepensis leaf-derived materials toward human intestinal bacteria were examined. The biologically active constituent of the R. chalepensis extract was characterized as quinoline-4-carboxaldehyde($C_{10}H_{7}NO$). The growth responses varied depending on the bacterial strain, chemicals, and dose tested. At 0.25 and 0.1 mg/disk, quinoline-4-carboxaldehyde strongly inhibited the growth of Clostridium perfringens and weakly inhibited the growth of Escherichia coli without any adverse effects on the growth of three lactic acid bacteria. Furthermore, at 0.05 and 0.025 mg/disk, this isolate showed moderate activity against C. perfringens. In comparison, chloramphenicol at as low as 0.01 mg/disk significantly inhibited the growth of all bacteria tested, and cinnamaldehyde at 0.25 mg/disk did not inhibit Bifidobacterium bifidum, B. longum, E. coli, and Lactobacillus acidophilus, with the exception of C. perfringens. The structure-activity relationship revealed that quinoline-3-carboxaldehyde had strong growth inhibition against C. perfringens, but quinoline, quinoline-3-carboxylic acid, and quinoline-4-carboxylic acid did not inhibit the growth of B. bifidum, B. longum, C. perfringens, E. coli, and L. acidophilus. These results indicate that the carboxyl aldehyde functional group of quinolines seems to be required for growth-inhibiting activity against C. perfringens, thus indicating at least one of the pharmacological actions of R. chalepensis leaf.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2010년도 정기총회 및 추계학술발표회
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• pp.18-18
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• 2010

Molecular insights on the role of plant growth promoting rhizobacteria (PGPR) in potato tuberization are reported in the present study. The PGPRwere isolated from the soil collected from potato fields of Highland Agricultural Research Centre, Pyeongchang, Korea and they were identified to the genus level based on the 16S rRNA sequence analysis. These PGPR were heat-killed, filtered and the filtrates were addedindividually at a concentration of $10^7\;cfu\;mL^{-1}$ in MS (Murashige and Skoog's) medium supplemented with 7% (w/v) sucrose to study their influence on in vitro potato tuberization. Tuber initiation occurred early in untreated control, while tuber growth was pronounced in case of PGPR treatments. The control explants showed tuber formation as a result of sub-apical swelling of stolons while several sessile tubers formed directly in the axils of nodal cuttings in case of PGPR treatments, which is an indication of strong induction for tuberization. Theexplants cultured on MS medium supplemented with bacterial isolate 6 (Bacillus firmus strain 40) showed highest average tuber yield (Ca. 12.56 g per treatment) after 30 days of culture, which was 3 folds increase over the untreated control. A significant increase in lipoxygenase (LOX1) mRNA expression and activity of LOX enzyme were also detected in the tubers induced on PGPR treatments as compared to untreated control. This LOX expression level correlated with increased tuber growth and tuber yield. Further studies focused on the role of bacteria cell wall components, growth regulators and signal molecules released by PGPR are under investigation to elicit clues for PGPR-mediated signal pathway controlling potato tuberization.

• Journal of Microbiology
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• 제44권3호
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• pp.363-368
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• 2006

In this study, native Byadyrhizobium strains were isolated from the host plant, Glycine max, harvested from fields in Madhya Pradesh, India, and were typed by Iytic rhizobiophages. Eight indigenous (Soy2, ASR011, ASR031, ASR032, MSR091, ISR050, ISR076 and ISR078) and two exotic strains (USDA123 and CB1809), all of which evidenced a distinct reaction with six phages, were employed in this study. The symbiotic interaction of these strains was studied initially using soybean cultivar JS335 in a sand culture in a controlled environment, and the efficiency was assessed based on the nodule number, nodule dry weight, plant dry weight, nitrogenase activity, and total accumulation of N per plant. Symbiotic effectiveness was found to be highest with the native phage-sensitive isolate ASR011, whereas it was at a minimum with the phage-resistant isolates, ISR050 and ISR078. Additionally, the effectiveness of these strains was evaluated using six soybean cultivars belonging to different maturity groups; namely, Brags, Lee, Pusa20, PK416, JS33S and NRC37. Analysis of variance data evidenced significant differences due to both symbionts, for the majority of the tested parameters. The CB1809, USDA123, and ASR011 strains evidenced relatively superior symbiotic effectiveness with soybean cultivars Brags, Lee and JS335. Strain ISR078 evidenced no significant responses with any of the cultivars. The ASR031 strain performed moderately well with all tested cultivars. The symbiotic response of all the strains was quite poor with cultivar PK416. Our studies showed that a significant relationship existed between the phage sensitivity and symbiotic efficiency of the bacterial strains with the host-cultivars.

• 한국미생물·생명공학회지
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• 제16권2호
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• pp.98-104
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• 1988

미생물 다당류중 viscosifier를 생산하는 세균을 분리하고 그 특성을 조사하였다. 본 세균은 Enterobacter agglomerans로 동정되었으며, 다당류 생산을 위한 조건은 glucose 25 g/ι, peptone 2.0 g/$\ell$, yeast extract 0.5 g/$\ell$, KH$_2$PO$_4$1g/$\ell$, MgSO$_4$.7$H_2O$ 1g/$\ell$, CaCO$_3$2.5g/$\ell$, 3$0^{\circ}C$ pH 5.7이며 이 조건에서의 생산량은 8.41g/L 이었다. 본 다당류의 성분은 갈락토오스(1.0몰), 크실로오스(1.5몰), 글루코 노델타락톤(1.9몰) 및 리보오스(0.03몰)로 되어 있었다. 1% 용액의 점도는 60rpm에서 504mpa.s이며 고유 점도는 45.8 d$\ell$/g 이었다

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.742-753
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• 2012

Copper-containing compounds are introduced into the environment through agricultural chemicals, mining, and metal industries and cause severe detrimental effects on ecosystems. Certain microorganisms exposed to these stressors exhibit molecular mechanisms to maintain intracellular copper homeostasis and avoid toxicity. We have previously reported that the soil bacterial isolate Achromobacter sp. AO22 is multi-heavy metal tolerant and exhibits a mer operon associated with a Tn21 type transposon. The present study reports that AO22 also hosts a unique cop locus encoding copper homeostasis determinants. The putative cop genes were amplified from the strain AO22 using degenerate primers based on reported cop and pco sequences, and a constructed 10,552 base pair contig (GenBank Accession No. GU929214). BLAST analyses of the sequence revealed a unique cop locus of 10 complete open reading frames, designated copSRABGOFCDK, with unusual separation of copCD from copAB. The promoter areas exhibit two putative cop boxes, and copRS appear to be transcribed divergently from other genes. The putative protein CopA may be a copper oxidase involved in export to the periplasm, CopB is likely extracytoplasmic, CopC may be periplasmic, CopD is cytoplasmic/inner membrane, CopF is a P-type ATPase, and CopG, CopO, and CopK are likely copper chaperones. CopA, B, C, and D exhibit several potential copper ligands and CopS and CopR exhibit features of two-component regulatory systems. Sequences flanking indicate the AO22 cop locus may be present within a genomic island. Achromobacter sp. strain AO22 is thus an ideal candidate for understanding copper homeostasis mechanisms and exploiting them for copper biosensor or biosorption systems.

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1386-1392
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• 2010

A bacterial strain designated GR5$^T$, previously isolated from a freshwater culture pond in Taiwan while screening for bacteria for antimicrobial compounds, was characterized using a polyphasic taxonomic approach. Strain GR5$^T$ was found to be Gram-negative, aerobic, greenish-yellow colored, rod-shaped, and motile by means of a single polar flagellum. Growth occurred at $10-40^{\circ}C$ (optimum, $35^{\circ}C$), pH 7.0-8.0 (optimum pH 8.0), and with 0-2.0% NaCl (optimum, 0.5-1.0%). The major fatty acids were $C_{16:1}{\omega}7c$(36.3%), $C_{16:0}$(16.6%), $C_{12:0}$ 3-OH (12.5%), and $C_{18:1}{\omega}7c$(9.1%). The major respiratory quinone was Q-8, and the DNA G+C content of the genomic DNA was 51.9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GR5$^T$ belongs to the genus Rheinheimera, where its most closely related neighbors are Rheinheimera texasensis A62-14B$^T$ and Rheinheimera tangshanensis JA3-B52$^T$ with sequence similarities of 98.1% and 97.5%, respectively, and the sequence similarities to any other recognized species within Gammaproteobacteria are less than 96.5%. The mean level of DNA-DNA relatedness between strain GR5$^T$ and R. texasensis A62-14B$^T$, the strain most closely related to the isolate, was $26.5{\pm}7.6%$. Therefore, based on the phylogenetic and phenotypic data, strain GR5$^T$ should be classified as a novel species, for which the name Rheinheimera aquatica sp. nov. is proposed. The type strain is GR5$^T$ (=BCRC 80081$^T$=LMG 25379$^T$).

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1614-1623
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• 2010

Bacteria were isolated from roots of sugarcane varieties grown in the fields of Punjab. They were identified by using API20E/NE bacterial identification kits and from sequences of 16S rRNA and amplicons of the cpn60 gene. The majority of bacteria were found to belong to the genera of Enterobacter, Pseudomonas, and Klebsiella, but members of genera Azospirillum, Rhizobium, Rahnella, Delftia, Caulobacter, Pannonibacter, Xanthomonas, and Stenotrophomonas were also found. The community, however, was dominated by members of the Pseudomonadaceae and Enterobacteriaceae, as representatives of these genera were found in samples from every variety and location examined. All isolates were tested for the presence of five enzymes and seven factors known to be associated with plant growth promotion. Ten isolates showed lipase activity and eight were positive for protease activity. Cellulase, chitinase, and pectinase were not detected in any strain. Nine strains showed nitrogen fixing ability (acetylene reduction assay) and 26 were capable of solubilizing phosphate. In the presence of 100 mg/l tryptophan, all strains except one produced indole acetic acid in the growth medium. All isolates were positive for ACC deaminase activity. Six strains produced homoserine lactones and three produced HCN and hexamate type siderophores. One isolate was capable of inhibiting the growth of 24 pathogenic fungal strains of Colletotrichum, Fusarium, Pythium, and Rhizoctonia spp. In tests of their abilities to grow under a range of temperature, pH, and NaCl concentrations, all isolates grew well on plates with 3% NaCl and most of them grew well at 4 to $41^{\circ}C$ and at pH 11.

• 한국미생물·생명공학회지
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• 제42권4호
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• pp.339-346
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• 2014

가정에서 제조된 된장으로부터 lactose를 glucose와 galactose로 가수분해하는 균체외 ${\beta}$-galactosidase의 생산균이 분리되었다. 분리균 YB-1414는 형태적 특성, 생화학적 성질 및 16S rRNA 유전자 염기서열에 근거하여 Bacillus licheniformis로 확인되었다. 탄소원과 질소원으로 밀기울 (1%)과 yeast extract (2.5%)를 사용하였을 때 B. licheniformis YB-1414의 ${\beta}$-galactosidase 생산성이 최대 6.2 U/ml에 이르렀다. 특히 밀기울의 불용성 성분이 수용성 성분보다 ${\beta}$-galactosidase 생산성을 더 증가 시키는 것으로 확인되었다. ${\beta}$-galactosidase의 para-nitrophenyl-${\beta}$-D-galactopyranoside 가수분해 활성은 pH 6.0과 $55-60^{\circ}C$에서 가장 높았으며, 낮은 농도의 galactose에 의해서도 크게 저해를 받았다. 그러나 glucose에 의해서는 ${\beta}$-galactosidase의 가수분해 활성이 약하게 저해를 받으며 400 mM glucose가 존재하여도 최대 활성의 85%에 해당하는 가수분해 활성을 보였다.