• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.893-902
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• 2011

Endophytic fungi are little known for their role in gibberellins (GAs) synthesis and abiotic stress resistance in crop plants. We isolated 10 endophytes from the roots of field-grown soybean and screened their culture filtrates (CF) on the GAs biosynthesis mutant rice line - Waito-C. CF bioassay showed that endophyte GMH-1B significantly promoted the growth of Waito-C compared with controls. GMH-1B was identified as Penicillium minioluteum LHL09 on the basis of ITS regions rDNA sequence homology and phylogenetic analyses. GC/MS-SIM analysis of CF of P. minioluteum revealed the presence of bioactive $GA_4$ and $GA_7$. In endophyte-soybean plant interaction, P. minioluteum association significantly promoted growth characteristics (shoot length, shoot fresh and dry biomasses, chlorophyll content, and leaf area) and nitrogen assimilation, with and without sodium chloride (NaCl)-induced salinity (70 and 140 mM) stress, as compared with control. Field-emission scanning electron microcopy showed active colonization of endophyte with host plants before and after stress treatments. In response to salinity stress, low endogenous abscisic acid and high salicylic acid accumulation in endophyte-associated plants elucidated the stress mitigation by P. minioluteum. The endophytic fungal symbiosis of P. minioluteum also increased the daidzein and genistein contents in the soybean as compared with control plants, under salt stress. Thus, P. minioluteum ameliorated the adverse effects of abiotic salinity stress and rescued soybean plant growth by influencing biosynthesis of the plant's hormones and flavonoids.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.470-475
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• 2002

In the course of screening for a novel cell cycle inhibitor, a potent Cdk 1 inhibitor, HY558, was found from the culture broth of Penicillium minioluteum F558 isolated from a soil sample. The molecular ion of HY558 was identified at m/z 329 (MH+) with a molecular formula of $C_20H_44ON_2$. HY558 exhibited selective antiproliferative effects on various human cancer cell lines. Its $IC_50$ values were estimated to be 0.29 mM on HepG2, 0.30 mM on HeLa, 0.30 mM on HL6O, 0.33 mM on HT-29, and 0.25 mM on AGS cells. Interestingly, Hy558 demonstrated no antiproliferative effect with normal lymphocytes used as the control, and a low level of inhibition on the proliferation of A549 cancer cells. A flow cytometric analysis of HepG2 cells revealed an appreciable arrest of cells at the G1 and G2/M phases of the cell cycle following treatment with Hy558. furthermore, DNA fragmentation due to apoptosis was observed in HeLa cells treated with 0.46 mM of HY558.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.978-984
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• 2004

In the course of screening for a novel inhibitor of CDC2, HY558-1 was isolated from a culture broth of Penicillium minioluteum F558. Moreover, it was found that HY558-1 had an effect on both the cell cycle regulation and apoptosis of human cervical adenocarcinoma HeLa cells. A flow cytometric analysis of HeLa cells revealed appreciable cell cycle arrest at the G1 and G2/M phases following treatment with HY558-1. Furthermore, DNA fragmentation due to apoptosis was observed in HeLa cells treated with HY558-1. To obtain further information on the cell cycle arrest and apoptotic induction induced by HY558-1, the expression of certain cell cycle and apoptosis-associated proteins was examined using a Western blot analysis. The results revealed that HY558-1 inhibited the phosphorylation of pRb and decreased the expression levels of CDK2, CDC2, and cyclin A in the cell cycle progression. It was also shown that the level of $p21^{WAF1/CIP1}$ was increased in HeLa cells treated with 0.52 mM of HY558-1. Accordingly, HY558-1 was found to inhibit the proliferation of HeLa cells through the induction of G1 phase arrest by inhibiting pRb phosphorylation via an upregulation of $p21^{WAF1/CIP1}$, and G2/M phase arrest by directly inhibiting CDC2 and cyclin A. Moreover, HeLa cells treated with 0.52 mM of HY558-1 exhibited apoptotic induction associated with the cleavage of Bid and release of cytochrome c from mitochondria into the cytosol. Subsequent investigation of the activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP) suggested that the mitochondrial pathway was primarily involved in the HY558-1-induced apoptosis in HeLa cells.

• Mycobiology
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• v.45 no.3
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• pp.178-183
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• 2017

Diabetes mellitus is a chronic disorder which affects millions of population worldwide. Global estimates published in 2010 reported the world diabetic prevalence as 6.4%, affecting 285 million adults. Foot ulceration and wound infection are major forms of disabilities arising from diabetic diseases. This study was aimed to develop a natural antimicrobial finishing on medical grade textile that meets American Association of Textiles Chemists and Colorists (AATCC) standard. The textile samples were finished with the ethanolic extract of Penicillium amestolkiae elv609, an endophytic fungus isolated from Orthosiphon stamineus Benth (common name: cat's whiskers). Endophyte is defined as microorganism that reside in the living plant tissue, without causing apparent disease symptom to the host. The antimicrobial efficacy of the ethanolic extract of P. minioluteum was tested on clinical pathogens isolated from diabetic wound. The extract exhibited significant inhibitory activity against 4 bacteria and 1 yeast with the minimal inhibitory concentration ranged from 6.25 to 12.5 mg/mL. The results indicate different susceptibility levels of the test microorganism to the ethanolic extract. However, the killing activity of the extract was concentration-dependent. The finished medical textile showed excellent antimicrobial efficacy on AATCC test assays. All the microbial cultures treated with the textile sample displayed a growth reduction of 99.9% on Hoheinstein Challenge Test. The wash durability of the finished textile was found good even after 50 washes with commercial detergent. Besides, the gas chromatography mass spectrometry analysis showed that 6-octadecenoic acid and diethyl phthalate were the main bioactive constituents of the extract. In conclusion, the developed medical textile showed good antimicrobial efficacy on laboratory tests. This work can be extended to in vivo trials for developing healthcare textile products for antimicrobial applications.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.402-406
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• 2005

Lipomyces starkeyi produces a novel glucanhydrolase containing endo-dextranase and ${\alpha}-amylase$ activities. A cDNA from L. starkeyi encoding a dextranase was isolated and characterized. The 2,052 kb cDNA fragment (lsd1) carrying dextranase gene showed one open reading frame (ORF) composed of 1,824 bp flanked by a 41 bp 5'-UTR and a 184 bp 3'-UTR including a poly(A) tail of 27 bp. The ORF encodes for a 608 amino acid with a predicted molecular mass of 67.6 kDa. There was 77% deduced amino acid sequence identity between the LSD1 dextranase and the dextranase from Penicillium minioluteum. The primary structure of the dextranase from L. starkeyi has distant similarity with enzymes belonging to glycosyl hydrolase family 49. The lsd1 protein was expressed in the Saccharmyces cerevisiae under control of GAL1 promoter and active dextranase was produced.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1506-1513
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• 2009

$\alpha$-Dextranase, which can hydrolyze dextran, is largely used in the sugar industry. However, a thermostable $\alpha$-dextranase is needed to alleviate the viscosity of syrups and clean blocked machines. Thus, to improve the optimal temperature of Lipomyces starkeyi $\alpha$-dextranase expressed by Pichia pastoris, the rational introduction of a de novo designed disulfide bond was investigated. Based on the known structure of Penicillium minioluteum dextranase, L. starkeyi $\alpha$-dextranase was constructed using homology modeling. Four amino acids residues were then selected for site-directed mutagenesis to cysteine. When compared with the wild-type dextranase, the mutant DexM2 (D279C/S289C) showed a more than $13^{\circ}C$ improvement on its optimal temperature. DexM2 and DexM12 (T245C/N248C, D279C/S289C) also showed a better thermal stability than the wild-type dextranase. After the introduction of two disulfide bonds, the specific activity of DexM12 was evaluated and found to be two times higher than that of the wild-type. Moreover, DexM12 also showed the highest $V_{max}$.