• Applied Microscopy
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• 제8권1호
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• pp.1-8
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• 1978

The aim of this research was to discover the action mechanism of various antituberculosis agents (isoniazid, paraaminosalicylic acid and streptomycin) which act on Mycobacteria tuberculosis hominis $H_{37}R_v$ and also to study the relationship of ultrastructural changes and the growth pattern in Mycobacterium tuberculosis hominis. The ultrastructural change was observed with an electron microscope while the growth pattern was studied through in vitro culture. The results are summarized as follows: 1. The ultrastructural changes found in the group treated only with isoniazid were the loss of nuclear materials and the appearence of electron dense granules. 2. In the group treated with paraaminosalicylic acid, thickening of nuclear filaments and meso some arrangement disorders were observed. 3. In the group treated with streptomycin, the ribosome particles appeared indistinct and the cytoplasm was denaturalized. 4. In the group cross treated with all three agents, all the ultrastructural changes mentioned above could be observed in the cell just as they appeared in the single treated groups. 5. In all of the single and in the crossly treated group, there were no significant changes note in the cell wall or cytoplasmic membranes of any of the cells observed. 6. In the cultural data in vitro, through the crossly treated group and single treated group. growth was observed in 3-5 weeks of culture.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.117-124
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• 1995

A gene (xynA) encoding the endo-xylanase (E.C.3.2.1.8) from Bacillus stearothermophilus was cloned in E. coli, and its complete nucleotide sequence was determined. The xynA gene consists of a 636 base pairs open reading frame coding for a protein of 212 amino acids with a deduced molecular weight of 23, 283 Da. A putative signal sequence of 27 amino acid residues shows the features comparable with the Bacillus signal sequences; namely, the signal contains a positively charged region close to the N-terminus followed by a long hydrophobic string. The coding sequence is preceded by a possible ribosome binding site with a free energy value of -16.6 kcal/mol and the transcription initiation signals are located further upstream. The translation termination codon (TAA) at the 3 end of the coding sequence is followed by two palindrome sequences, one of which is thought to act as a terminator. The xynA gene has a high GC content, especially in the wobble position of codons (64%). Comparison of the primary protein sequence with those of other xylanases shows a high homology to the xylanases belonging to family G.

• Clinical and Experimental Pediatrics
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• 제51권10호
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• pp.1031-1037
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• 2008

Macrolide antimicrobial agents including erythromycin, roxithromycin, clarithromycin, and azithromycin are commonly used in the treatment of respiratory tract infections in children. Newer macrolides that have structural modifications of older drug erythromycin show improved change in the spectrum of activity, dosing, and administration. However, recent studies reported that increasing use of macrolide antibiotics is the main force driving the development of macrolide resistance in streptococci. In particular, azithromycin use is more likely to select for macrolide resistance with Streptococcus pneumoniae than is clarithromycin use, a possible reflection of its much longer half life. Recently, erythromycin resistance rates of S. pneumoniae and Streptococcus pyogenes are rapidly increasing in Korea. Two main mechanisms of acquired macrolide resistance have been described, altered binding site on the bacterial ribosome encoded by the ermB gene and active macrolide efflux pump encoded by the mef gene. Relationship between the susceptibility of S. pneumoniae and the response to macrolides has been shown in studies of acute otitis media, but less clear in cases of pneumonia. This article reviews the spectrum of activity, pharmacokinetic properties, mechanisms of action and resistance, and clinical implication of resistance on the treatment of respiratory tract infections in children.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.37-44
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• 1991

A shuttle promoter-probe vector, pEB203, was derived from pBR322, pPL703 and pUB110. Using the vector, a useful DNA fragment, 319 bp EcoRI fragment, having strong promoter activity has been cloned from Bacillus subtills chromosomal DNA. Selection was based on chloramphenicol resistance which is dependent upon the introduction of DNA fragments allowing expression of a chloramphenicol acetyl transferase gene. The nucleotide sequence of the 319 bp fragment has been determined and the putative -35 and -10 region, ribosome binding site, and ATG initiation codon were observed. This promoter was named EB promoter and the resultant plasmid which can be used as an expression vector was named pEBP313. The crystal protein gene from B. thuringiensis subsp. kurstaki HD-73 was cloned downstream from the EB promoter without its own promoter. When the resultant plasmid, pBT313, was introduced into Escherichia coli and B. subtilis, efficient synthesis of crystal protein was observed in both cells, and the cp gene expression in B. subtilis begins early in the vegetative phase. The cell extracts from both clones were toxic to Hyphantria cunea larvae.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2002년도 춘계학술발표대회 발표논문초록집
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• pp.87-87
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• 2002

Previously, we observed high level expression of goat β-casein/genomic hGH fusion gene in mammary gland of transgenic mice. To develop an expression vector to make a human granulocyte-colony stimulating factor (hG-CSF) protein efficiently produced in milk of transgenic animals, we designed a new bicistronic vector using the goat β-casein/genomic hGH fusion gene as regulation sequences for expression and internal ribosome entry site (IRES) as a mediator for second gene expression. This vector was constructed by insertion of encephalomyocarditis virus (EMCV) IRES-dependent second gene region coupled with hG-CSF cDNA into 3' untranslated region of an intact hGH gene. By microinjcetion, four transgenic mice were generated and three of them transmitted the bicistronic vector to their progeny. (omitted)

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.337-341
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• 2001

To isolate antifungal substances from Korean radish (Raphanus Sativus L.) seeds, various purification techniques such as DE52 cellulose anion exchange, SP-Sephadex C-25 cation exchange, and Sephadex G-50 gel filtration chromatographies were used. The molecular masses of two purified R. sativus antifungal proteins (RAPs) were estimated to be about 6.1 kDa (RAP-1) and 6.2 kDa (RAP-2) by SDS-PAGE, and 5.8 kDa(RAP-1) and 6.2 kDa (RAP-2 by a gel filtration chromatography, respectively. Purified proteins RAP-1 and 2 clearly exhibited different growth inhibitory activities against other microorganisms like Candida albicans and Saccharomyces cerevisiae. Although they have similar molecular masses, both RAP-1 and 2 proteins are not identical because their microbial inhibitory actions were different. Therefore, RAP-1 could be a new antifungal protein when compared with the antifungal activities of 2S albumins, Rs-AFPs, Mj-AMPs, chitinase, glucanase, permatin, and ribosome inactivating proteins, all of which are anifungal proteins of plants.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.593-598
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• 2004

The arsenical resistance (ars) operon was cloned from a 67-kilobase pair (kb) plasmid, which was previously shown to be responsible for arsenic salts resistance in K. oxytoca D12. When plasmid pAE48, carrying the ars operon, was transformed into E. coli, transformed cells displayed enhanced survival in the presence of 4 mM arsenite, 50 mM arsenate, or 0.4 mM antimonite. The nucleotide sequence of the 5.6-kb fragment encoding arsenical resistance revealed five open reading frames (ORFs), which were predicted to encode polypeptides of 12.8 (arsR), 13.4 (arsD), 62.6 (arsA), 45 (arsB), and 16.7 (arse) kilodaltons (kDa). Each ORF was preceded by a ribosome binding site. A putative promoter-like sequence was identified upstream of arsR, and a possible termination site was found downstream of arsC. When the deduced amino acid sequences of the K. oxytoca Dl2 Ars proteins were compared with the amino acid sequences of the E. coli R773 Ars proteins, a significant amino acid similarity was observed (87.9％ for ArsR, 89.2％ for ArsD, 83.2％ for ArsA, 92.6％ for ArsB, and 91.3％ for ArsC), suggesting an evolutionary relationship of the ars genes of E. coli plasmid R773 and K. oxytoca Dl2.

• Journal of Microbiology and Biotechnology
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• 제9권2호
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• pp.230-233
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• 1999

A plasmid vector was constructed for the expression and secretion of Bacillus macerans cyclodextrin glucanotransferase (CGTase) in Bacillus subtilis. The vector, pUBACGT, was composed of the ribosome-binding sequence, signal sequence, and cgt gene from B. macerans under the control of amyR2, the promoter of amyE gene coding for $\alpha$-amylase from B. subtilis var. natto. Bacillus subtilis LKS88, a mutant strain lacking genes for an amylase and two proteases, was used as a host for the transformation of the plasmid vector. The transformants were selected on kanamycin-containing Luria-Bertani plates. The starch hydrolyzing activity was observed on the starch-containing plates by the iodine method and cyclodextrin-forming activity was detected in the culture medium. A SDS-PAGE analysis showed that most of the expressed CGTase in the recombinant B. subtilis was secreted into the medium at a high expression level.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.823-827
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• 2003

Streptomyces venezuelae ATCC 15439 is notable in its ability to produce two distinct groups of macrolactones. It has been reported that the generation of two macrolactone structures results from alternative expression of pikromycin (Pik) polyketide synthase (PKS). It was previously reported that the hybrid pikromycin-tylosin PKS can also produce two different macrolactones but its mechanistic basis remains unclear. In order to address this question, a series of site-directed mutagenesis of tentative alternative ribosome binding site and translation start codons in tylGV were performed. The results suggest that macrolactone ring size is not determined by the alternative expression of TylGV but through other mechanism(s) involving direct interaction between the PikAIII and TE domain or skipping of the final chain elongation step. This provides new insight into the mechanism of macrolactone ring size determination in hybrid PKS as well as an opportunity to develop novel termination activities for combinatorial biosynthesis.

• Journal of Microbiology and Biotechnology
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• 제3권3호
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• pp.139-145
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• 1993

The nucleotide sequence of the xylanase gene (xynS) from alkali-tolerant Bacillus sp. YA.14 was determined and analyzed. A 639 base pairs open reading frame for xynS gene was observed and encoded for a protein of 213 amino acids with a molecular weight of 23, 339. S1 nuclease mapping showed that the transcription initiation site of the xynS gene did not exist in the cloned DNA. Ribosome binding site sequence with the free energy of -18.8 Kcal/mol was observed 8 base pairs upstream from the initiation codon, ATG. The proposed signal sequence consisted of 28 amino acids, of which 3 were basic amino acid residues and 21 were hydrophobic amino acid residues. When the amino acid sequences of xylanases were compared, Bacillus sp. YA-14 xylanase showed 48% homology with Bacillus sp. YC-335 xylanase and 96% homology with xylanases from B. subtilis and B. circulans.