• 한국미생물·생명공학회지
• /
• 제46권4호
• /
• pp.346-359
• /
• 2018

Xanthomonas oryzae, a bacterial pathogen causing leaf blight disease (BLB) in rice, can cause widespread disease and has caused epidemics globally, resulting in severe crop losses of 50% in Asia. The pathogen is seed-borne and is transmitted through seeds. Thus, control of BLB requires the elimination of the pathogen from seeds. Concern about environment-friendly organic production has spurred improvements in a variety of biological disease control methods, including the use of bacteriophages, against bacterial plant pathogens. The present study explored the potential of bacteriophages isolated from diseased plant leaves and soil samples in killing the bacterial pathogen in rice seeds. Eight different phages were isolated and evaluated for their bacteriolytic activity against different pathogenic X. oryzae strains. Of these, a phage designated ${\varphi}XOF4$ killed all the pathogenic X. oryzae strains and showed the broadest host range. Transmission electron microscopy of ${\varphi}XOF4$ revealed it to be a tailed phage with an icosahedral head. The virus was assigned to the family Siphoviridae, order Caudovirales. Seedlings raised from the seeds treated with $1{\times}10^8pfu/ml$ of ${\varphi}XOF4$ phage displayed reduced incidence of BLB disease and complete bacterial growth inhibition. The findings indicate the potential of the ${\varphi}XOF4$ phage as a potential biological control agent against BLB disease in rice.

• 한국식물생명공학회:학술대회논문집
• /
• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
• /
• pp.219-219
• /
• 2005

• 한국미생물·생명공학회지
• /
• 제21권3호
• /
• pp.207-213
• /
• 1993

Total 176 alginate-degrading bacterial strains were isolated from marine moluscus, marine echonodermata, seaweed, and soils. Among the isolates, five strains (No. 28, 51, 79, 135, and 145) had higher level of alginate-degrading activity. The isolate No. 28, 51, 79, and 135 were identified as the genus Enterobacter and the strain No. 145 as the genus Vibrio. We used these strains to examine the optimal conditions for the production of alginate-degrading activity.

• 미생물학회지
• /
• 제27권2호
• /
• pp.124-129
• /
• 1989

In order to improve the production of bacterial alginate, Azotobacter vinelandii NCIB 8789 was treated with 200.$\mu$g/ml of MNNG for obtaining mutant strain. The mutant HB18 was selected, which produced the highest amount of alginic acid among the survival stains. The HB18 produced 5.4g/l of alginic acid when batch cultured at $30^{\circ}C$ for 160 hrs and its alginic acid showed high molecular weight and simple composition when compared with thoseof wild type.

• 대한화장품학회지
• /
• 제13권1호
• /
• pp.36-44
• /
• 1987

Seven bacterial strains capable of conversing Gardenia irridoidglucoside into blue color was isolated on nutrient agar plates with 0.1% water extracted solution of Gardenia's dryad seed. In the seven, strain No. C2 was most effective in the production of blue color. The optimal conditions in production of blue color were when initial pH of medium was 7.0 and cultivation temperature was 35$^{\circ}C$. In 5 $\ell$-Jar fermantor, the powder of blue color was produced about 15% (W/W). And the color was relatively stable in our test.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제21권4호
• /
• pp.332-344
• /
• 1999

Cytokines are hormone-like proteins which mediate and regulate inflammatory and immune responses. Interleukin-6 (IL-6) is involved in the final differentiation of B cells into antibody-producing cells. Interleukin-8 (IL-8) is a neutrophil chemotactic factor that plays an important role in the recruitment of neutrophil to inflammatory loci. Inflammatory mediators by cells in the gingiva have been implicated in the initiation and progression of periodontitis and oral infection. The purpose of this study was conducted to investigate the effect of lipopolysaccharide (LPS), staphylococcus enterotoxin B (SEB) on production of IL-6 and IL-8 by human gingival and facial dermal fibroblasts. Primary cultured human gingival and facial dermal fibroblasts were incubated with LPS (0.01, 0.1, $1.0{\mu}g/ml$), SEB (0.01, 0.1, $1.0{\mu}g/ml$) or LPS $(0.1{\mu}g/ml)$ plus SEB $(0.1{\mu}g/ml)$. Culture supernatants were collected at 24, 48, and 72 hrs and assessed for IL-6 and IL-8 production by enzyme-linked immunosorbent assay. IL-6 production in gingival fibroblasts stimulated with LPS was higher than that with SEB. IL-6 production by double exposure with LPS plus SEB was amplified in comparison with single exposure of LPS or SEB. IL-6 production in facial dermal fibroblasts was increased only by stimulation with a high concentration of LPS $(1.0{\mu}g/ml)$. Its production in facial dermal fibroblasts by exposure with SEB was decreased in comparison with control, nontreated cells. Therefore, gingival fibroblasts showed higher sensitivity than facial dermal fibroblasts in response to low concentration of LPS. Also, IL-6 production by double exposure with LPS plus SEB was amplified in comparison with single exposure of LPS or SEB. IL-8 production in gingival fibroblasts was enhanced greatly only by stimulation of high concentration of LPS $(1.0{\mu}g/ml)$. That by exposure with SEB was increased only in 24 hrs cultivation. IL-8 production by double exposure with LPS plus SEB was amplified in comparison with single exposure of LPS or SEB. IL-8 production in facial dermal fibroblasts was decreased by LPS and increased only in 48 hrs cultivation by SEB. IL-8 production by double exposure with LPS plus SEB was enhanced only in 48 hrs cultivation in comparison with single exposure of LPS or SEB. therefore, IL-6 and IL-8 production were released at various quantities according to bacterial toxin applied and site of fibroblast harvested. These results suggest that gingival fibroblasts may be concerned with IL-6 and IL-8 related inflammatory response more than facial dermal fibroblasts.

• Environmental Engineering Research
• /
• 제19권4호
• /
• pp.355-361
• /
• 2014

The wastewater treatment with a two-phase expanded granular sludge bed (EGSB) system for anaerobic degradation of acetate, benzoate, terephtalate and p-toluate from purified terephtalic acid (PTA) production was studied. The feasibility and effectiveness of the system was evaluated in terms of organic oxidation by chemical oxygen demand (COD), gas production, bacterial adaptability and stability in the granular sludge. Average removal efficiencies 93.5% and 72.7% were achieved in the EGSB reactors under volumetric loading rates of $1.0-15kg-COD/m^3/day$ and terephtalate and p-toluate of 351-526 mg/L, respectively. Gas production reached total methane production rate of 0.30 L/g-COD under these conditions in the sequential EGSB reactor system. Higher strength influent COD concentration above 4.8 g-COD/L related to field conditions was fed to observe the disturbance of the EGSB reactors.

• 미생물학회지
• /
• 제26권4호
• /
• pp.362-367
• /
• 1988

The strain YL 38-3, which was capable of producing extracellular cytosine deaminase, was isolated and taxonomically examined. The isolated strain was identified to be Bacillus polymyxa YL 38-3. The optimal conditions for the enzyme production from Bacillus polymyxa YL 38-3 were investigated. The enzyme production was reached maximum level in the medium containing 0.5% glucose, 0.2% beef extract, 0.5% NaCl and 0.1% $KH_{2}PO_{4}$ (pH 6.0). And the enzyme showed the highest activity when the strain YL 38-3 was cultivated at $35^{\circ}C$ for 24 gours under the initial pH 6.0. By the additions of peptone the extracellular enzyme production was inhibited, meanwhile the intracellular enzyme production was highly stimulated. It was, therefore, deduced that peptone was related to the secretion mechanism of the enzyme from this bacterial cell.

• 한국응용곤충학회지
• /
• 제49권4호
• /
• pp.409-416
• /
• 2010

곤충병원세균인 Photorhabdus temperata ssp. temperata(Ptt)는 곤충의 면역반응을 억제시켜 피기생 곤충 체내에서 공생하는 기주 선충의 발육을 도모하게 된다. 또한 Ptt의 변역억제 활성은 Bacillus thuringiensis(Bt)의 병원성을 증가시킨다. 본 연구는 이러한 유용 곤충병원세균의 대량 생산을 위한 저렴한 배지를 선발하기 위해 수행되었으며, 두 연구용 배지(LB, TSB)와 저렴한 산업용 두 배지(MY, M2)를 상호 비교하였다 모든 배양액에 동일한 밀도의 Ptt를 접종하고 배양하였을 때 48 시간 이후 정지상이 나타났다. 그러나 연구용 배양액인 LB와 TSB에서 두 가지 산업용 배양액보다 정지상에서 높은 세균 밀도를 보였다. 네 가지 배지에서 증식된 Ptt 배양액은 모두 배추좀나방(Plutella xylostella) 3령충에 대한 Bt 병원성을 현격하게 제고시켰고, 이들 배지 종류에 따라 치아가 없었다. 네 가지 배양액에서 세균의 증식에 의해 생산되는 대시물질의 양과 배지별 생산되는 대사물질의 동일성을 확인하기 위해 헥산과 에틸아세테이트의 유기용매로 추출했다. 시간별 배양액의 유기용매 추출물질은 세균의 증식과 비슷하게 대사물질의 생산량에서도 증가하는 것을 알 수 있었다. 역상 HPLC를 이용하여 네 가지 세균 배양액 각각에서 대사물질을 분리하였고, 정량적으로 네 가지 대사물질이 서로 다른 배지에서 통계적으로 차이 없이 검출되었다. 본 연구는 비교적 저렴한 두 가지 산업용 배지가 유용 대사물질의 생성에 변화 없이 Ptt 세균을 저렴하게 배양할 수 있다고 제시하고 있다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제26권2호
• /
• pp.266-274
• /
• 2013

The effect of different phytogenic feed additives on reducing odorous compounds in swine was investigated using in vitro fermentation and analyzed their microbial communities. Soybean meal (1%) added with 0.1% different phytogenic feed additives (FA) were in vitro fermented using swine fecal slurries and anaerobically incubated for 12 and 24 h. The phytogenic FAs used were red ginseng barn powder (Panax ginseng C. A. Meyer, FA1), persimmon leaf powder (Diospyros virginiana L., FA2), ginkgo leaf powder (Ginkgo biloba L., FA3), and oregano lippia seed oil extract (Lippia graveolens Kunth, OL, FA4). Total gas production, pH, ammonianitrogen ($NH_3$-N), hydrogen sulfide ($H_2S$), nitrite-nitrogen ($NO_2{^-}$-N), nitrate-nitrogen ($NO_3{^-}$-N), sulfate (${SO_4}^{--}$), volatile fatty acids (VFA) and other metabolites concentration were determined. Microbial communities were also analyzed using 16S rRNA DGGE. Results showed that the pH values on all treatments increased as incubation time became longer except for FA4 where it decreased. Moreover, FA4 incubated for 12 and 24 h was not detected in $NH_3$-N and $H_2S$. Addition of FAs decreased (p<0.05) propionate production but increased (p<0.05) the total VFA production. Ten 16S rRNA DGGE bands were identified which ranged from 96 to 100% identity which were mostly isolated from the intestine. Similarity index showed three clearly different clusters: I (FA2 and FA3), II (Con and FA1), and III (FA4). Dominant bands which were identified closest to Eubacterium limosum (ATCC 8486T), Uncultured bacterium clone PF6641 and Streptococcus lutetiensis (CIP 106849T) were present only in the FA4 treatment group and were not found in other groups. FA4 had a different bacterial diversity compared to control and other treatments and thus explains having lowest odorous compounds. Addition of FA4 to an enriched protein feed source for growing swine may effectively reduce odorous compounds which are typically associated with swine production.