• The Plant Pathology Journal
• /
• 제31권3호
• /
• pp.278-289
• /
• 2015

Indigenous strains of Trichoderma species isolated from rhizosphere soils of Tea gardens of Assam, north eastern state of India were assessed for in vitro antagonism against two important tea fungal pathogens namely Pestalotia theae and Fusarium solani. A potent antagonist against both tea pathogenic fungi, designated as SDRLIN1, was selected and identified as Trichoderma viride. The strain also showed substantial antifungal activity against five standard phytopathogenic fungi. Culture filtrate collected from stationary growth phase of the antagonist demonstrated a significantly higher degree of inhibitory activity against all the test fungi, demonstrating the presence of an optimal blend of extracellular antifungal metabolites. Moreover, quantitative enzyme assay of exponential and stationary culture filtrates revealed that the activity of cellulase, ${\beta}$-1,3-glucanase, pectinase, and amylase was highest in the exponential phase, whereas the activity of proteases and chitinase was noted highest in the stationary phase. Morphological changes such as hyphal swelling and distortion were also observed in the fungal pathogen grown on potato dextrose agar containing stationary phase culture filtrate. Moreover, the antifungal activity of the filtrate was significantly reduced but not entirely after heat or proteinase K treatment, demonstrating substantial role of certain unknown thermostable antifungal compound(s) in the inhibitory activity.

• International Journal of Advanced Culture Technology
• /
• 제9권4호
• /
• pp.29-39
• /
• 2021

Cognitive behavioral therapy (CBT) is effective for people with an addiction tendency. This study aims to implement a CBT program for college students at high risk of smartphone addiction and investigate the impact of the program on their desire to use a smartphone, depression, impulsivity, and anxiety. Baseline/post-intervention evaluation and the ABA' single-case experimental design were used. The study consisted of the baseline phase (A), pre-evaluation, intervention phase (B), post-evaluation, and baseline phase (A'). Six participants were enrolled, and the main outcome variables were daily changes in the desire to use a smartphone and changes in depression, impulsivity, and anxiety after the program. Prior to the intervention, all six participants had mild to moderate depression, but after the intervention, three were normal, two had mild depression, and only one had moderate depression. Impulsivity and anxiety scores decreased after the intervention, with anxiety scores showing the most dramatic change. The percentage of non-overlapping data for the baseline phase (A)-intervention phase (B) was more than 75% and that for baseline phase (A)-baseline phase (A') was 100% for all 6 participants. This study presented a good protocol for people with low access to psychological therapy. We expect the findings will be highly useful for people suffering from psychological difficulties due to smartphone addiction.

• 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.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 춘계학술발표대회
• /
• pp.470-473
• /
• 2000

Indole은 미생물에 강한 독성을 가지고 있으므로 indole의 생물학적 전환이 어려우므로 단지 소수의 미생물들이 Indole이나 그것의 연관물질들로부터 Indigo와 Indirubin을 생산하는데 응용되어 왔다. 본 연구실에서 분리된 Pseudomonas savastanoi BCNU 106은 toluene에 강한 내성을 가졌으며 P. savastanoi BCNU 106의 Indole 내성 정도는 p-xylene이나 toluene이 배지 부피의 20% 로 첨가되었을 때 160 mg/ml로 매우 높은 내성 정도를 나타내었다. Indole (100 mg/ml) 과 p-xylene (0.2 ml/ml)을 포함한 two-phase culture system에서 자란 P. savastanoi BCNU 106은 indole로부터 푸른색 indigo나 보라색 indirubin의 미생물학적 전환을 보여주었다. indigo와 indirubin의 생산은 P. savastanoi BCNU 106가 적절한 농도의 유기용매가 중층된 two-phase system에서 자랐을 경우에만 형성되었다. 그러므로 본 연구는, 분리된 indole 내성 세균이 유기용매하에서 indirubin과 같은 산업적 가치를 가진 유용물질을 생산하는데 응용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
• /
• 제31권3호
• /
• pp.456-463
• /
• 2021

In this study, the culture conditions for Porphyridium cruentum were optimized to obtain the maximum biomass and lipid productions. The eicosapentaenoic acid content was increased by pH optimization. P. cruentum was cultured with modified F/2 medium in 14-L photobioreactors using a two-phase culture system, in which the green (520 nm) and red (625 nm) light-emitting diodes (LEDs) were used during the first and second phases for biomass production and lipid production, respectively. Various parameters, including aeration rate, light intensity, photoperiod, and pH were optimized. The maximum biomass concentration of 0.91 g dcw/l was obtained with an aeration rate of 0.75 vvm, a light intensity of 300 μmol m-2s-1, and a photoperiod of 24:0 h. The maximum lipid production of 51.8% (w/w) was obtained with a light intensity of 400 μmol m-2s-1 and a photoperiod of 18:6 h. Additionally, the eicosapentaenoic acid and unsaturated fatty acid contents reached 30.6% to 56.2% at pH 6.0.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2001년도 추계학술발표대회
• /
• pp.545-548
• /
• 2001

Microbiologically influenced corrosion (MIC) of metal is common in the natural environment and sulfate reducing bacteria are representative microorganisms for MIC. We found that biofilm fomlation by SRB on the metal surface might be controlled by quorum sensing, which is a cell density dependent regulation of cell metabolism. As cell free culture fluids (spent media) of Desulfovibrio vulgaris and D. desulfuricans were tested for quontrn sensing related test strains, it was found that spent media of two SRB induced increased luminescence of Vibrio harveyi BB886 (sensor 1+, sensor 2-) and BB170 (sensor 1-, sensor 2+). Quorum activities of D. vulgaris and D. desulfuricans appeared to be parallel to growth patterns, i.e., it was low in the lag phase, highly increased in the exponential phase, and reached maximum in the stationary phase. Interestingly, however, luminescence of V. harveyi BB886 and BB170 induced by a unit cell mass of the SHB showed a maximal peak in the late lag phase. Hence, it was suspected that quorum sensing of these two SHB play unknown roles in shifting cells from dormant to growth stages.

• Journal of Microbiology and Biotechnology
• /
• 제14권1호
• /
• pp.216-219
• /
• 2004

The effect of culture temperature on the production of soluble form of B. macerans cyclodextrin glucanotransferase (CGTase) in recombinant E. coli was investigated. E. coli cell was cotransformed with two plasmids (pTCGT1 and pGroll) in which the cgt and groEL/ES genes are under the control of T7 promoter and pzt-1 promoter, respectively. When tetracycline (10 ng/ml) and IPTG (l mM) were added as inducers at the early-exponential phase (2 h) and mid-exponential phase (3h), respectively, the solubilization of the inclusion body CGTase was greatly dependent on the temperature of the culture. At low culture temperature of $25^\circ{C}$, 2- or 3-fold higher activity and specific activity were obtained over $37^\circ{C}$. SDS-PAGE analysis revealed that about 62% of CGTase in the total CGTase protein was found in the soluble fraction by applying overexpression of GroEL/ES chaperone and by cultivation of E. coli at $25^\circ{C}$, whereas 33% of CGTase was detected in the soluble fraction at $37^\circ{C}$. Therefore, the expression of GroEL/ES and cultivation at $25^\circ{C}$ greatly enhanced the soluble production of CGTase in E. coli.

• 한국미생물·생명공학회지
• /
• 제19권5호
• /
• pp.521-535
• /
• 1991

Cephalosporium 배양시 균체의 형태학적 측면을 고려한 cephalosporin C 생합성에 대한 모델식을 제안하였다. 제한기질로 glucose와 methionine을 고려한 double-substrate 모델을 설정하였는데 여기서 glucose는 균체의 증식 정도를, methionine은 균체의 증식속도를 제어하게 된다. Cephalosporin C의 생산은 균체의 형태학적 분화와 밀접한 관계가 있다. 한편 cephalosporin C의 생산성을 증대시키기 위해 모델식을 유가식 배양에 응용하였다.

• Archives of Pharmacal Research
• /
• 제19권3호
• /
• pp.173-177
• /
• 1996

The Pneumococcus, Streptococcus pneumoniae, has an ample polysaccharide (PS) capsule that is highly antigenic and is the main virulence factor of the organism. The capsular PS is the source of PS vaccine. This investigation was undertaken to optimize the culture conditions for the production of capsular PS by type 4 pneumococcus. Among several culture media, brain heart infusion (BHI) and Casitone based medium were found to support luxuriant growth of pneumococcus type 4 at the same level. Therefore in this study, the Casitone based medium was used to study optimization of the culture condition because of BHI broth's high cost and complex nature. The phase of growth which accomodated maximum PS production was exponential phase. Concentrations of glucose greater than 0.8% did not enhance growth or PS production. Substitution of nitrogen sources with other resources or supplementation of various concentrations of metal ion (with the exception of calcium, copper, and magnesium ions) had adverse effects on growth and PS production. On the other hand, low level aeration and supplementation of 3 mg/l concentration of asparagine, phenylalanine, or threonine were beneficial for increased PS production. The synergistic effect of all the favorable conditions observed in pneumococcal growth assays provided a two-fold cumulative increase in capsular PS production.

• 농업과학연구
• /
• 제45권4호
• /
• pp.677-685
• /
• 2018

Weaning pigs often face post-weaning challenges such as diarrhea, low feed intake, and body weight (BW) loss which affects the health and economic value of weaning pigs. Interestingly, the use of yeast cultures (YCs) as feed supplements for pigs has increased markedly in recent years. This study evaluated the effects of yeast cultures (Saccharomyces cerevisiae) on the growth performance, fecal score, and nutrient digestibility of weaning pigs. A total of 50 crossed healthy weaning pigs [(Yorkshire ${\times}$ Landrace) ${\times}$ Duroc] with an average BW of $7.46{\pm}1.60kg$ (28 day of age) were used in a 6-week experiment. The experiment was divided into 3 phases (Phase 1, 1 - 2 weeks; Phase 2, 2 - 4 weeks; Phase 3, 4 - 6 weeks). Dietary treatments were as follows: 1) CON: basal diet and 2) CON + 0.50% YC. During phase 1, the average daily gain (ADG) and average daily feed intake (ADFI) were significantly increased (p < 0.05) in the weaning pigs fed YC supplementation diets compared with the weaning pigs fed the CON diet. During phase 3 as well as overall, the gain/feed ratio (G/F) was significantly increased (p < 0.05) in the YC supplementation group compared with the pigs fed the CON diet. In conclusion, the supplementation of YCs in the diet positively affected the growth performance of weaning pigs during the first two weeks after weaning.