• Title/Summary/Keyword: Mutant strain

Search Result 687, Processing Time 0.028 seconds

Pro-Apoptotic Role of the Human YPEL5 Gene Identified by Functional Complementation of a Yeast moh1Δ Mutation

  • Lee, Ji Young;Jun, Do Youn;Park, Ju Eun;Kwon, Gi Hyun;Kim, Jong-Sik;Kim, Young Ho
    • Journal of Microbiology and Biotechnology
    • /
    • v.27 no.3
    • /
    • pp.633-643
    • /
    • 2017
  • To examine the pro-apoptotic role of the human ortholog (YPEL5) of the Drosophila Yippee protein, the cell viability of Saccharomyces cerevisiae mutant strain with deleted MOH1, the yeast ortholog, was compared with that of the wild-type (WT)-MOH1 strain after exposure to different apoptogenic stimulants, including UV irradiation, methyl methanesulfonate (MMS), camptothecin (CPT), heat shock, and hyperosmotic shock. The $moh1{\Delta}$ mutant exhibited enhanced cell viability compared with the WT-MOH1 strain when treated with lethal UV irradiation, 1.8 mM MMS, $100{\mu}M$ CPT, heat shock at $50^{\circ}C$, or 1.2 M KCl. At the same time, the level of Moh1 protein was commonly up-regulated in the WT-MOH1 strain as was that of Ynk1 protein, which is known as a marker for DNA damage. Although the enhanced UV resistance of the $moh1{\Delta}$ mutant largely disappeared following transformation with the yeast MOH1 gene or one of the human YPEL1-YPEL5 genes, the transformant bearing pYES2-YPEL5 was more sensitive to lethal UV irradiation and its UV sensitivity was similar to that of the WT-MOH1 strain. Under these conditions, the UV irradiation-induced apoptotic events, such as FITC-Annexin V stainability, mitochondrial membrane potential (${\Delta}{\psi}m$) loss, and metacaspase activation, occurred to a much lesser extent in the $moh1{\Delta}$ mutant compared with the WT-MOH1 strain and the mutant strain bearing pYES2-MOH1 or pYES2-YPEL5. These results demonstrate the functional conservation between yeast Moh1 and human YPEL5, and their involvement in mitochondria-dependent apoptosis induced by DNA damage.

Isolation of a Mutant with Thermotolerance and Ethanol Tolerance Using Proofreading-deficient DNA Polymerases in Saccharomyces cerevisiae (출아효모에서 proofreading-deficient DNA polymerase를 이용한 내열성 및 에탄올내성 변이 주의 분리)

  • Kim, Yeon-Hee
    • Journal of Life Science
    • /
    • v.29 no.8
    • /
    • pp.916-921
    • /
    • 2019
  • In this study, we constructed a biological system that exhibited thermotolerance, ethanol tolerance, and increased ethanol productivity using a random mutagenesis method. We attempted to isolate a thermotolerant mutant using proofreading-deficient DNA polymerase ${\delta}$ and ${\varepsilon}$ encoded by the pol3 and pol2 genes, respectively, in Saccharomyces cerevisiae. To obtain mutants that could grow at high temperatures ($38^{\circ}C$ and $40^{\circ}C$), random mutagenesis of AMY410 (pol2-4) and AMY126 (pol3-01) strains was induced. The parental strains (AMY410 and AMY126) grew poorly at temperatures higher than $38^{\circ}C$. By stepwise elevation of the incubation temperature, AMY410-Ht (heat tolerance) and AMY126-Ht strains that proliferated at $40^{\circ}C$ were obtained. These strains were further incubated in medium containing 6% and 8% ethanol and then AMY410-HEt (heat and ethanol tolerance) and AMY126-HEt strain with ethanol tolerance at an 8% ethanol concentration was obtained. The AMY126-HEt strain grew even at an ethanol concentration of 10%. Furthermore, following the addition of high concentrations of glucose (5% and 10%), an AMY126-HEt3 strain with increased ethanol productivity was isolated. This strain produced 24.7 g/l of ethanol (95% theoretical conversion yield) from 50 g/l of glucose. The findings demonstrate that a new biological system (yeast strain) showing various phenotypes can be easily and efficiently bred by random mutagenesis of a proofreading- deficient mutant.

Comparison of Bacterial Cellulose Production in a Jar Fermentor Between Acetobacter xylinum BPR2001 and its Mutant, Acetan-Nonproducing Strain EP1

  • BAE SANG OK;SUGANO YASUSHI;SHODA MAKOTO
    • Journal of Microbiology and Biotechnology
    • /
    • v.15 no.2
    • /
    • pp.247-253
    • /
    • 2005
  • The bacterial cellulose (BC) production by a wild­strain Acetobacter xylinum BPR2001 and that by its acetan­nonproducing mutant, EPI, were compared in a jar fermentor. EPI produced about $28\%$ less BC than the wild-strain. The apparent difference in the cultivation of the two strains was the viscosity increase in the culture broth that was closely associated with acetan production. Increasing the viscosity of the culture broth of EPI by adding agar led to the formation of relatively small and uniform BC pellets, and BC production consequently became two-fold higher than that in the absence of agar and was almost equal to that by BPR2001. Therefore, acetan has an important role in BC production by inducing physical changes in the culture broth of the wild-type strain.

Antibacterial Activities of Methylelaiophylin (Methylelaiophylin의 항균활성)

  • Lee, Dong-Sun;Lee, Sang-Han;WOO, Ju-Hyung;Lee, Jin-Man;Seu, Young-Bae;Hong, Soon-Duck
    • Journal of Life Science
    • /
    • v.7 no.3
    • /
    • pp.180-185
    • /
    • 1997
  • Methylelaiophylin generated superoxide radicals in Bacillus subtilis and showed antibacterial activity against a broad range of gram positive bacteria. The inhibition of DNA synthesis was more sensitive than one of RNA synthesis. A recombination-deficient mutant strain of B. subtilis was 2-fold more sensitive than a wild strain, and this sensitivity was reduced in the presence of an antioxidant, dithiothreitol. Methylelaiophylin generated superoxide radicals in B. subtilis lysates, and this suggests that the antibacterial activity of methylelaiophylin is related to the generation of active oxygen species in the cells.

  • PDF

Isolation and Characterization of Oxygen-tolerant Mutant of Bifidobacterium longum. (Bifidobacterium longum 산소변이주의 분리와 변이주의 산소내성)

  • 안준배;김광엽;박종현
    • Microbiology and Biotechnology Letters
    • /
    • v.26 no.6
    • /
    • pp.476-482
    • /
    • 1998
  • Growth sensitivity of bifidobacteria on oxygen hindered their industrial applications so that it was necessary to select oxygen-tolerant strains. Studies on their responses to oxygen might facilitate the effective utilization of bifidobacteria in industry. Oxygen-tolerant strain of Bifidobacterium longum JI-1 was able to remove 3% dissolved oxygen within 10 min whilst oxygen-sensitive strain of B. adolescentis, slime non-former, was not. The ability to remove environmental oxygen seemed to be related to the oxygen-tolerance of bifidobacteria. Mutant B. longum ADJ-1 was induced from the B. longum JI-1 under microaerobic atmosphere. There were no differences in sugar utilization pattern, NADH oxidative enzymes and cellular fatty acid compositions between them. The maximal cell density of the mutant was a little bit reduced to 81% of that of the mother strain. However, the mutant formed thick slime layer around its cell. The layer visualized with confocal scanning laser microscopy from the mutant was 6 ${\mu}{\textrm}{m}$ in diameter but that from the mother strain was only 3 ${\mu}{\textrm}{m}$. Therefore, the improved tolerances of the mutant might come from the slime layer, indicating the increase of the layer might be one of oxygen tolerance mechanisms for bifidobacteria.

  • PDF

Optimization of Mutant Strain of the Sulfur-Oxidizing Bacteria, Thiobacillus sp. UIW-6 (황산화 세균 Thiobacillus sp. UIW-6 변이주의 성장 최적화)

  • Shin, Seung-Yong;Kang, Sun-Chul
    • Korean Journal of Environmental Agriculture
    • /
    • v.25 no.2
    • /
    • pp.124-128
    • /
    • 2006
  • To reducing offensive odor form compost UIW-6 mutant obtained by UV treatment from sulfur-oxidizing bacteria, Thiobacillus sp. IW. The UIW-6 mutant was found 1.6 times faster in growth than the parent strain on thiosulfate medium (TM) at 36 h after incubation. Initial pH, temperature and agitation for the optimum growth of UIW-6 were 6.5, $35^{\circ}C$ and 200 rpm, respectively. The UIW-6 mutant growth was two times higher than parent strain at 6 h culture in TM liquid medium containing 50 mM sodium thiosulfate. The UIW-6 mutant used fructose and sucrose as carbon sources and yeast extract> tryptone> peptone as nitrogen ones. It was found that the growth of UIW-6 was increased in addition of 0.2% yeast extract.

Effect of Various Carbon Sources on the Development of Aspergillus nidulans with $velA^+$ or velA1 allele (각종 탄소원이 $velA^+$ 및 velA1 Aspergillus nidulans의 분화에 미치는 영향)

  • Han, Dong-Min;Han, Yoo-Jeong;Chae, Keon-Sang;Jahng, Kwang-Yeop;Lee, Young-Hoon
    • The Korean Journal of Mycology
    • /
    • v.22 no.4
    • /
    • pp.332-337
    • /
    • 1994
  • Under standard condition (Han, et al., 1990: glucose 1%-nitrate 0.1% minimal medium, 30 ml in 9 cm plate, $10^6$ cells of inoculum per plate), wild type of Aspergillus nidulans developed both sexual and asexual organs in ballance, while velA1 mutant developed asexual ones preferentially. Increase of glucose concentration did not significantly affect the asexual sporulation. However, development of sexual organs were largely affected. It was greatly enhanced when favorable nitrogen source, for example, casein hydrolysate was added, which is contrary to the case of Neurospora or Saccharomyces where limitation of N source induces sexual development. On most of moderate C sources asexual development in $velA^+$ strain was largely inhibited except acetate on which only asexual spores were produced, while that in velA1 mutant strain was not affected. Lactose promoted the sexual development even in velA1 mutant indicating that lactose itself or its metabolic intermediate may induce sexual development independent of allelic state of velA gene. On other moderate favorable C sources, glycerol, galactose and ethanol, asexual development was largely inhibited in $velA^+$ strain but not in velA1 mutant strain. Sexual organs were, however, never produced on acetate. These results suggested that asexual development of wild type is largely dependent on C sources and the velA gene is involved in the repression of asexual development in not-enough-grown (non-competent) thalli resulting in preferential progression of sexual development.

  • PDF

Antibiotic-Resistance Profiles and the Identification of the Ampicillin-Resistance Gene of Vibrio parahaemolyticus Isolated from Seawater (해수에서 분리한 장염비브리오의 항생제 내성 및 암피실린 내성 유전자의 동정)

  • Lee, Kuen-Woo;Park, Kwon-Sam
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.43 no.6
    • /
    • pp.637-641
    • /
    • 2010
  • The antibiotics-resistance profiles of 28 strains of Vibrio parahaemolyticus isolated from seawater were investigated. All of the strains studied were resistant to ampicillin (100%), but susceptible to 12 other antibiotics. The minimum inhibitory concentration (MIC) of V. parahaemolyticus to ampicillin was as high as $1,024-2,048\;{\mu}g{\cdot}mL^{-1}$. The phenotype of strain 8 changed from ampicillin-resistant to susceptible with an in-frame deletion mutant of VPA0477, a putative ${\beta}$-lactamase gene, and the MIC for ampicillin of the mutant strain was $1{\mu}g{\cdot}mL^{-1}$. In conclusion, our findings suggest that the VPA0477 gene acts as a ${\beta}$-lactamase in ampicillin-resistant V. parahaemolyticus strains.

Selection of Yeast Mutant Strain with High RNA Content and Its High Cell-Density Fed-Batch Culture. (고함량 RNA 효모 변이주의 선별 및 고농도세포 유가배양)

  • 김재범;권미정;남희섭;김재훈;남수완
    • Microbiology and Biotechnology Letters
    • /
    • v.30 no.1
    • /
    • pp.68-72
    • /
    • 2002
  • To obtain a yeast mutant with high RNA content and high growth rate, Saccharomyces cerevisiae MTY62 was mutated with ethylmethane sulfonate. Among the selected mutants that were sensitive to the high concentration of KCl, M40-10 strain was finally selected due to its rapid cell growth and high RNA content in the tube and baffled-flask cultures. In the batch culture of M40-10 mutant, the maximum specific growth rate ($\mu_{max}$) of $0.38 h^{-1}$ , RNA concentration of 3210 mg-RNA/1, and RNA content of 183 mg-RNA/g-DCW were obtained, which were 23%, 15%, and 12% increased levels, respectively, compared to those of MTY62 parent strain. The intermittent fed-batch culture of M40-10 strain resulted in the maximum cell concentration of 35.6 g-DCW/1, RNA concentration of 5677 mg/1, and RNA content of 160 mg-RNA/g-DCW. Through the constant fed-batch culture, the maximum cell concentration of 46.4 g-DCW/1, RNA concentration of 6270 mg-RNA/1, and RNA content of 135 mg-RNA/g-DCW were obtained. At the 20 h culture time in the fed-batch cultures of M40-10 strain, the cell and RNA concentrations were increased by 30% and 10%, respectively, over the parent strain MTY62. In addition, it was also found that the accumulated RNA within the mutant cell was not degraded until the end of fed-batch cultivation, indicating that the M40-10 cell is a mutant with weak acidic RNase activity.y.