• 대한화학회지
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• 제64권4호
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• pp.225-230
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• 2020

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3515-3516
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• 2010

• Mycobiology
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• 제39권4호
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• pp.272-277
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• 2011

Chemical mutagenesis of basidiospores of Hypsizygus marmoreus generated new mushroom strains. The basidospores were treated with methanesulfonate methylester, an alkylating agent, to yield 400 mutant monokaryotic mycelia. Twenty fast-growing mycelia were selected and mated each other by hyphal fusion. Fifty out of the 190 matings were successful (mating rate of 26.3%), judged by the formation of clamp connections. The mutant dikaryons were cultivated to investigate their morphological and cultivation characteristics. Mutant strains No. 3 and No. 5 showed 10% and 6% increase in fruiting body production, respectively. Eight mutant strains showed delayed and reduced primordia formation, resulting in the reduced production yield with prolonged cultivation period. The number of the fruiting bodies of mutant No. 31, which displayed reduced primordial formation, was only 15, compared to the parental number of 65. Another interesting phenotype was a fruiting body with a flattened stipe and pileus. Dikaryons generated by mating with the mutant spore No. 14 produced flat fruiting bodies. Further molecular biological studies will provide details of the mechanism. This work shows that the chemical mutagenesis approach is highly utilizable in the development of mushroom strains as well as in the generation of resources for molecular genetic studies.

• Mycobiology
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• 제41권3호
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• pp.159-163
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• 2013

A chemical mutagenesis technique was employed for development of mutant strains of Sparassis crispa targeting the shortened cultivation time and the high ${\beta}$-glucan content. The homogenized mycelial fragments of S. crispa IUM4010 strain were treated with 0.2 vol% methyl methanesulfonate, an alkylating agent, yielding 199 mutant strains. Subsequent screening in terms of growth and ${\beta}$-glucan content yielded two mutant strains, B4 and S7. Both mutants exhibited a significant increase in ${\beta}$-glucan productivity by producing 0.254 and 0.236 mg soluble ${\beta}$-glucan/mg dry cell weight for the B4 and S7 strains, respectively, whereas the wild type strain produced 0.102 mg soluble ${\beta}$-glucan/mg dry cell weight. The results demonstrate the usefulness of chemical mutagenesis for generation of mutant mushroom strains.

• BMB Reports
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• 제42권6호
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• pp.315-323
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• 2009

In order to elucidate ultimate biological function of the genome, the model animal system carrying mutations is indispensable. Recently, large-scale mutagenesis projects have been launched in various species. Especially, the mouse is considered to be an ideal model to human because it is a mammalian species accompanied with well-established genetic as well as embryonic technologies. In 1990', large-scale mouse mutagenesis projects firstly initiated with a potent chemical mutagen, N-ethyl-N-nitrosourea (ENU) by the phenotype-driven approach or forward genetics. The knockout mouse mutagenesis projects with trapping/conditional mutagenesis have then followed as Phase II since 2006 by the gene-driven approach or reverse genetics. Recently, the next-generation gene targeting system has also become available to the research community, which allows us to establish and analyze mutant mice carrying an allelic series of base substitutions in target genes as another reverse genetics. Overall trends in the large-scale mouse mutagenesis will be reviewed in this article particularly focusing on the new advancement of the next-generation gene targeting system. The drastic expansion of the mutant mouse resources altogether will enhance the systematic understanding of the life. The construction of the mutant mouse resources developed by the forward and reverse genetic mutagenesis is just the beginning of the annotation of mammalian genome. They provide basic infrastructure to understand the molecular mechanism of the gene and genome and will contribute to not only basic researches but also applied sciences such as human disease modelling, genomic medicine and personalized medicine.

• Toxicological Research
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• 제24권1호
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• pp.59-68
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• 2008

N-ethyl-N-nitrosoures (ENU) is effective in inducing hypermorphic mutation as well as hypomorphic and antimorphic mutations. Therefore, this mutagen is used to the production of mutant in the mice. In order to perform an effective ENU mutagenesis using BALB/cAnN mice, determination of optimal dosage and dosage regimen of ENU is necessary. And this study tried to develop a suitable screening method and searched for novel and various mutants as model animals in phenotypedriven ENU mutagenesis. We have carried out dosage regimen for mutagenizing dose of 200 mg/kg ENU in the BALB/c mice. Total screened mice were 30,133. As the results of Esaki and Cho's Phenotype Screening, we got 2,516 phenotypic and behavior abnormalities in $G_1,\;G_2\;and\;G_3$ mice. One hundred thirty five $G_1$ phenodeviants were tested for inheritance and 16 dominant mutants were discovered. Forty two recessive mutants were also found in tested 201 micropedigrees. Early-onset mutant mice included the dysmorphology of face, eye, tail, limb, skin, and foot and abnormal behavior like circling, swimming, head tossing, stiff-walking, high cholesterol level, and tremor etc. In this study we could effectively screen $G_3$ recessive mutants. The frequent and concise early-onset screening before weaning will be available for ENU mutagenesis.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.4106-4108
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• 2011

• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.11-17
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• 2015

In an attempt to shift the optimal pH of the xylanase B (XynB) from Aspergillus niger towards alkalinity, target mutation sites were selected by alignment between Aspergillus niger xylanase B and other xylanases that have alkalophilic pH optima that highlight charged residues in the eight-residues-longer loop in the alkalophilic xylanase. Multiple engineered XynB mutants were created by site-directed mutagenesis with substitutions Q164K and Q164K+D117N. The variant XynB-117 had the highest optimum pH (at 5.5), which corresponded to a basic 0.5 pH unit shift when compared with the wild-type enzyme. However, the optimal pH of the XynB-164 mutation was not changed, similar to the wild type. These results suggest that the residues at positions 164 and 117 in the eight-residues-longer loop and the cleft's edge are important in determining the pH optima of XynB from Aspergillus niger.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1621-1622
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• 2013

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2248-2252
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• 2007

SOMT-9 is an O-methyltransferase that utilizes quercetin to produce 3'-methoxy quercetin. In order to determine which amino acids of SOMT-9 are important for this reaction and its regioselectivity, molecular docking experiments followed by site directed mutagenesis were performed. Molecular modeling and molecular docking experiments identified several amino acid residues involved in metal binding, AdoMet binding, and substrate binding. Site-directed mutagenesis showed that Asp188 is critical for metal binding and that Lys165 assists other metal binding residues in maintaining quercetin in the proper position during the reaction. In addition, Tyr207 was shown to play an important role in the determination of the regioselectivity and Met60 was shown to be involved in formation of the hydrophobic pocket necessary for substrate binding. The molecular modeling and docking experiments discussed in this study could be applicable to future research including prediction of substrate binding and regioselectivity of an enzyme.