• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.998-1000
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• 2003

This study was carried out to elucidate the mode of bacteriostatic property of xanthostatin (XS), a novel depsipeptide antibiotic with an N-acetylglycine side chain and selective antimicrobial activity against Xanthomonas spp. Two biotransformed XSs were isolated by the treatment of XS with the cell lysate of Xanthomonas campestris pv. citri, a solvent partition, preparative TLC, and HPLC. Structure determination of those two biotransformed XSs demonstrated deletion of the N-acetylglycine side chain. Noteworthily, they showed no antimicrobial activity against Xanthomonas spp. This result suggests that the N-acetylglycine side chain plays a critical role in the antimicrobial activity of XS, and that the bacteriostatic property of XS is due to susceptibility of the ester bond between the hexadepsipeptide nucleus and the N-acetylglycine side chain to hydrolytic enzyme(s) produced by Xanthomonas spp.

• Journal of Microbiology and Biotechnology
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• v.10 no.1
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• pp.111-114
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• 2000

Streptomyces are widespread in nature and play a very important role in the biosynthesis as well as biodegradation of natural and unnatural aromatic compounds. Both qualitatively and quantitatively through TLC and UV spectrophotometric assays, it was observed that the thermophilic soil bacteria S. setonii (ATCC 39116), which can utilize a benzoate as a sole carbon and energy source in a minimal liquid culture, was not very sensitive to the benzoate concentation and to the culture conditions such as the pH and temperature. The in vitro conversion of a catechol to a cis, cis-muconic acid by a crude S. setonii lysate implies that the aromatic ring cleavage by S. setonii is initiated by a thermostable catechol-1,2-dioxygenase, the key enzyme in the ortho-cleavage pathway of aromatic compound biodegradation. Unlike non-degrading S. lividans, S.setonii was also highly resistant to other similar hazardous aromatic compounds, exhibiting almost no adverse effect on its growth in a complex liquid culture.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.232-239
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• 1991

Caboxymethyl cellulase (CMCase) I was purified from the induced culture filtrate of Penicllium verruculosum F-3 by ammonium sulfate precipitation, DEAE-Sephadex A-50 chromatography and Bio-gel P-150 filtration. The purified enzyme was assumed to be a glycoprotein consisting of 8.5% carbohydrate and having a molecular weight of 70.000 in SDS-polycrylamide gel electrophoresis (SDS-PAGE). The purified enzyme-specific anti-CMCase I IgG was obtained by rabbit immunization and protein A-sepharose CL-4B chromatography. The fungal poly($A^+$) RNA was isolated from the total RNA of the mycelium grown under cellulase induction conditions by oligo(dT)-cellulosse chromatography. The translation products in vitro were prepared by translating the isolated poly ($A^+$) RNA in rabbit reticulocyte lysate and analyzed by SDS-PAGE and fluorography. Of the translation products, CMCase I was identified by the immunoprecipitation against anti-CMCase I IgG.

• Korean Journal of Microbiology
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• v.15 no.3
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• pp.131-138
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• 1977

The effects of various nitrogen soruces on the expression of nif gene were investigated using nif-lac fusants of Klebsiella pneumoniae. K. pneumoniae UK 2979 was infected with Mudl lysate prepared by heat induction of K. pneumoniae UK 4482. About 80 nif-lac fusants were greatly repressed. Amino acids, such as serine, glutamine and asparagine, were found to support the growth of K. pneumoniae M5al quite well, and showed a repressive effect on .betha.-galactosidase activities of nif-lac fusants LX-9 and LX-22 in NFHM. Glutamic acid, histidine and arginine rendered poor growth but high activities of .betha.-galactosidase. Good cell growth and high enzyme activity were observed when complex nitrogen sources, such as casitone, proteose pepone, were employed. .betha.-Galactosidase activities of LX-9 and LX-22 in nitrogen free minimal medium increased sharply within first 4 hours.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.132-135
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• 2003

Endotoxin concentrations were measured from 69 point-of-use(POU) water treatment system(WTS) by using Limulus amebocyte lysate(LAL) assay, and the results were compared to heterotrophic bacterial data. Endotoxin concentrations in all POU WTS water samples and tap waters varied within the range 0.8-79.1EU mL$\^$-1/ and 0.1-3.4EU mL$\^$-1/, respectively, The correlations between endotoxin concentration and HPC bacteria from the water samples showed not significant(r=0.18).

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.270-273
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• 2004

Lactobacillus spp.의 항산화 효과를 측정한 결과 L. bulgaricus LB 207의 cell lysate와 intact cell 모두에서 항산화 효과가 높게 측정되었다. 또한 이들 균주들은 높은 ferrous iron 흡착능을 나타내었으나 항산화 효과 사이의 연관성을 설명하기는 어려웠다. 유산균의항산화 메커니즘과 in vivo 실험을 통한 더욱 구체적인 항산화 효과에 대한 연구가 필요 하며, 다양한 항산화 메커니즘을 통하여 항산화 유산균 인간의 활성산소 축적의 위험으로부터 보호해 줄 수 있을 것으로 생각된다.

• BMB Reports
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• v.31 no.2
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• pp.135-138
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• 1998

A previous study on a yeast protein tyrosine phosphatase, YPTP1, using synthetic phosphotyrosine-containing peptides with various sequences as substrates revealed that DADEpYDA exhibits high affinity ($K_m=4{\mu}M$) toward the enzyme. A modified version of this peptide, GDADEpmFDA, immobilized on a resin, was used in this study as an affinity ligand for the purification of YPTP1. Phosphonomethyl-phenylalanine (pmF) was used as a nonhydrolyzable analog of the phosphotyrosine (pY) residue, with properties similar to pY. A protected form of pmF, $Fmoc-pmF(^{t}Bu)_{2}-OH$, was chemically synthesized and introduced during solid-phase peptide sythesis. YPTP1 was onrexpressed in an E. coli strain carrying a plasmid pT7-7-ptpl. Affinity chromatography of the crude lysate afforded PTPI (39 kDa) of about 50% purity.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1716-1722
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• 2018

Immunosuppressive drugs are used to make the body less likely to reject transplanted organs or to treat autoimmune diseases. In this study, five immunosuppressive drugs including two glucocorticoids (dexamethasone and prednisolone), one calcineurin inhibitor (cyclosporin A), one non-steroid anti-inflammatory drug (aspirin), and one antimetabolite (methotrexate) were tested for their effects on viral proliferation using feline foamy virus (FFV). The five drugs had different cytotoxic effects on the Crandell-Ress feline kidney (CRFK) cells, the natural host cell of FFV. Dexamethasone-pretreated CRFK cells were susceptible to FFV infection, but pretreatment with prednisolone, cyclosporin A, aspirin, and methotrexate showed obvious inhibitory effects on FFV proliferation, by reducing viral production to 29.8-83.8% of that of an untreated control. These results were supported by western blot, which detected viral Gag structural protein in the infected cell lysate. As our results showed a correlation between immunosuppressive drugs and susceptibility to viral infections, it is proposed that immune-compromised individuals who are using immune-suppressive drugs may be especially vulnerable to viral infection originated from pets.

• YAKHAK HOEJI
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• v.48 no.1
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• pp.47-54
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• 2004

ClpP is a stress-inducible protein and proteolytic subunit of the ATP-dependent Clp protease in prokaryotes and eukaryotes. Although its physiological roles in bacterial virulence were widely studied in various organsims, including Streptococcus pneumoniae, until now the immunological effect has not been investigated. Here, we have examined the cross reactivity of S. pneumoniae ClpP antibody with other organisms's cell lysate proteins. Although the protein sequence of S. pneumoniae ClpP was highly conserved among various organisms including human, the antibody rasised by S. pneumoniae ClpP was not cross-reacted with other organism's cell lysates, which were Saccharomyces cerevisiae , human lung A549 cell, Bacillus subtilis, Pseuomonas aeruginosa, E. coli, and Salmonella typhi. It was only reacted with S. pneumoniae and Lato-bacillus thermophilus. Thus we examined the immunoprotective effect of ClpP by immunizing mice with the purified ClpP. The mean survival time of mouse was significantly increased with the ClpP immunization. These results suggest that S. pneumoniae ClpP could be used as a vaccine candidate for prevention of S. pneumoniae infection.

• Microbiology and Biotechnology Letters
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• v.21 no.2
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• pp.132-138
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• 1993

The s-type pyocin was purified from the lysate of the mitomycin C-induced Pseudomonas aeruginosa 90-2-2205 cells by the other of ammonium sulfate precipitation, DEAE-Sephadex A-50 chromatography and Sephadex G-200 gel filtration. The purity was confirmed by the polyacry-lamide gel electrophoresis. The molecular weight of the purified pyocin was estimated 180, 000 by gel filtration. The pyocin was analyzed to be a complex of some polypeptides by the SDS-PAGE. The pyocin was stable by heat treatment and at pH 6-7.5 by adding 10-3% gelatin and 0.2M NaCl to the 10mM Tris-HCl buffer (pH7.5). Its killing action against the sensitive cells was assumably a single hit process.