• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.683-686
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• 1999

Four mutants of Acetobacter xylinum BRC5 defective in gluconic acid production were isolated from UV-irradiated cells. The gluconic acid-negative mutants did not show glucose oxidase activity. The mutants were also defective in cellulose production. A randomly selected mutant grown in the Hestrin-Schramm medium (pH 6.0) supplemented with gluconic acid, however, was found to synthesize cellulose. The mutant grown in Hestrin-Schramm medium whose pH was adjusted to 5.0 with HC1 and contained no gluconic acid also produced cellulose. Wild-type cells grown under the same condition synthesized cellulose more rapidly than those grown in the pH 6.0 medium.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.653-657
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• 2004

The cold resistant mutants of P. fluorescens strain $PRS_{9}$ and ATCC13525 were developed which could grow equally well at $28^{\circ}C$ and $10^{\circ}C$. All the mutants were tested for siderophore production, of which $CRPF_9$ (ATCC13525 mutant) was selected, as there was a 16.8-fold increase when compared to its wild-type. Under in vitro conditions, $CRPF_9$ showed better growth promotion both in wheat (29.1% increase in root length) and mung bean (51.5% increase in root length) at $10^{\circ}C$. Greenhouse trials showed a significant increase in root (13.84cm) and shoot (15.0cm) length of $CRPF_9$-treated mung bean seeds, indicating increased rhizocompetence of the mutant. Ferric citrate was a better iron source than ferric hydroxide for plant growth.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.2
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• pp.133-140
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• 2001

PAP-I cDNA was synthesized from total RNA of Phytolacca americana leaves by RT-PCR, and then subcloned to recombinant vector pBluescript II SK-. Using PCR with primers designed in our laboratory, we could get the 9 deletion mutant PAP-I cDNA fragments. The first of the fragments was deleted by 66bp from immature N-terminal and then the rest were deleted by 90bp sequentially. Sequentially deletion mutant PAP-I cDNAs were inserted to pAc55M, on down-stream of gall promoter. Recombinant pAc55M was transformed to yeast cells, psy1 and the cells were spreaded on SC_urn-/glucose plate media. Colonies on SC_ura-/glucose plate were streaked on the same position of SC_ura-/glucose and SC_ura-/galactose plate, and we selected colonies growing on both plates, which carry non-cytotoxic deleted mutant PAP-I cDNA. We selected 4 deletion mutant PAP-I cDNAs which have not cytotoxicity.

• Molecules and Cells
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• v.23 no.2
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• pp.154-160
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• 2007

An Arabidopsis hy4 mutant that is specifically impaired in its ability to undergo blue light dependent photomorphogenesis was used to identify cryptochrome 1 signaling-related components. Proteomic analysis revealed about 205 differentially expressed protein spots in the blue light-irradiated hy4 mutant compared to the wild-type. The proteins corresponding to 28 up-regulated and 33 down-regulated spots were identified. Obvious morphological changes in the hy4 mutant were closely related to the expression of various transcription factors. Our findings suggest that blue light signals may be involved in many cellular processes including disease resistance and stress responses.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.3
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• pp.417-422
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• 2007

A new evolution method termed queen-bee and mutant-bee evolution is based on the previous queen-bee evolution [1]. Even though the queen-bee evolution has shown very good performances, two parameters for strong mutation are added to the genetic algorithms. This makes the application of genetic algorithms with queen-bee evolution difficult because the values of the two parameters are empirically decided by a trial-and-error method without a systematic method. The queen- bee and mutant-bee evolution has no this problem because it does not need additional parameters for strong mutation. Experimental results with typical problems showed that the queen-bee and mutant-bee evolution produced nearly similar results to the best ones of queen-bee evolution even though it didn't need to select proper values of additional parameters.

• YAKHAK HOEJI
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• v.58 no.1
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• pp.7-11
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• 2014

To study the resistance mechanism of E. faecalis to LCB01-0371, several resistant mutants to LCB01-0371 or linezolid were isolated by step-wise selection. The frequency of spontaneous mutations resistant to LCB01-0371 was lower than that of linezolid in E. faecalis. The genetic variations in resistant mutants were analyzed by DNA sequencing of domain V of 23S rRNA in each mutant. The first-step mutant to LCB01-0371 had a G2576T point mutation in V domain of 23S rRNA. However, no resistant mutant to LCB01-0371 was isolated in second-step mutant selection.

• Archives of Pharmacal Research
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• v.22 no.1
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• pp.13-17
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• 1999

The kinetic constants and the reaction mechanism of the K228G mutant horse liver alcohol dehyrogenase isoenzyme E (HLADH-E) were compared to the wild-type enzyme. All the Km and Ki constants of the mutant enzyme for NAD+, ethanol, acetaldehyde and NADH were larger than those of the wild-type enzyme. The dissociation constants for the NADH and $NAD^{+}$ (Kiq and Kia) were greatly increased by 130-and 460-fold, respectively. The product inhibition patterns suggested that the reaction mechanism of the mutant enzyme was changed to Random Bi Bi. These results could attribute to the increase in the dissociation rate of coenzyme with the substitution at Lys-228 residue.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1336-1342
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• 2012

In Burkholderia pseudomallei, the pathogen that causes melioidosis, the gene cluster encoding the capsular polysaccharide, is located on chromosome 1. Among the 19 capsular genes in this cluster, wzm has not been thoroughly studied. To study the function of wzm, we generated a deletion mutant and compared it with the wild-type strain. The mutant produced less biofilm in minimal media and was more sensitive to desiccation and oxidative stress compared with the wild-type strain, indicating that wzm is involved in biofilm formation and membrane integrity. Scanning electron microscopy showed that the bacterial cells of the mutant strain have more defined surfaces with indentations, whereas cells of the wild-type strain do not.

• Journal of Microbiology
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• v.41 no.1
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• pp.41-45
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• 2003

N crassa mutant strain nap showed reduced growth rate, decreased electric membrane potential, and elevated intracellular ATP content in comparison to the wild type. Blue light induced a hyperpolarization of the membrane potential in both strains. The analysis of oxidative and phosphorylation activities of mitochondria isolated from the two strains has revealed that nap utilized more efficient oxidative pathways. The higher intracellular ATP content in the nap was presumably due to impaired transport systems of the plasma membrane, and to a lesser extent to the functioning of the fully competent respiratory chain. The excess ATP possibly accounts for carotenoid accumulation in the mutant.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.05a
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• pp.244-245
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• 2001

산폐유의 농도를 l~8% 까지 단계별로 조정하여 P. aeruginosa EMS1과 mutant strain A34의 유화활성 및 생육도, 표면장력 등을 서로 비교하였다. P. aeruginosa의 경우 1%의 산폐유가 첨가되었을 때 유화활성이 가장 높았으며, 1~3%까지 유화활성이 높게 나타났으며, mutant strain의 경우 2%에서 가장 높은 유화활성 값을 나타내었고, 1~3%까지 유화활성이 높게 유지되었다. P. aeruginosa EMS1 및 mutant strain A34 모두 4% 농도에서 가장 높게 나타났다. 표면장력과 biosurfactant의 상대적인 양을 나타내는 Fcmc의 경우 P. aeruginosa EMS1 보다 mutant strain A34가 우수하게 나타났다. PCR 결과 P. aeruginosa EMS1은 rhlamnolipid의 coding 유전자인 rhlRAB gene을 가지는 것으로 확인되었다.