• The Journal of Korean Institute of Communications and Information Sciences
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• 제36권7C호
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• pp.481-487
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• 2011

Cyclic delay diversity (CDD) is a simple transmit diversity technique for an OFDM system using multiple transmit antennas. However, the performance of post-FFT estimation, i.e., integer frequency offset (lFO) is deteriorated by high frequency selectivity introduced by CDD. In this paper, the IFO estimation scheme is proposed for OFDM-based DRM+ system with CDD. Based on the pilot subset partitioning, the proposed IFO estimation scheme reduces the effect of performance degradation caused by frequency selectivity in OFDM systems with CDD . The simulation results show that the performance of the proposed IFO estimator is significantly improved when compared to that of the conventional IFO estimator.

• Journal of the Korean Society of Food Science and Nutrition
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• 제20권2호
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• pp.179-186
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• 1991

The nutritional requirement and cultural condition such as carbon and nitrogen sources, cultural temperature, initial pH, cultural time and aeration for the production of endocellular cytosine deaminase from Aspergillus fumigatus IFO 5840 were investigated. The cultural broth giving maximum cytosine deaminase yield was found to consist of 2% glucose as a carbon source and 1% yeast extract and 0.1% peptone as a nitrogen source. Optimal initial pH of the culture broth was pH 8.5 and the enzyme production in the cell usually reached a maximum after 28 hours of cultivation in the 500ml shaking flask containing 100ml broth at $30^{\circ}C$. The endoenzyme production of the used strain was inhibited by inorganic nitrogen, but activated by orgainc nitrogen, yeast extract.

• Journal of Microbiology
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• 제38권3호
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• pp.160-168
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• 2000

A-factor I a microbial hormone that can positively control cell differentiation leading to spore formation and secondary metabolite formation in Streptomyces griseus. to identify a protease that is deeply involved in the morphological and physiological differentiation of Streptomyces, the proteases produced by Streptomyces griseus IFO 13350 and its A-factor deficient mutant strain, Streptomyces griseus HH1, as well as Streptomyces griseus HH1 transformed with the afsA gene were sturdied. In general Streptomyces griseus showed a higher degree of cell growth and protease activity in proportion to its ability to produce a higher amount of A-factor. In particular, the specific activity of the trypsin of Streptomyces griseus IFO 13350 was greatly enhanced more than twice compared with that of Streptomyces griseus HH1 in the later stage of growth. The specific activity of the metalloprotease of Streptomyces griseus HH1 was greatly enhanced more than twice compared with that of Streptomyces griseus IFO 13350, and this observation was reversed in the presence of thiostreptione, However, Streptomyces griseus HH1 transformed with the afsA gene showed a significantly decreased level of trypsin and metalloprotease activity compared with that of the HH1 strain. There was no significant difference between Streptomyces griseus IFO 13350 and HH1 strain in their chymotrypsin and thiol protease activity, yet the level of leu-amionpeptidase activity was 2 times higher in Streptomyces griseus HH1 than in strain IFO 13350 . Streptomyces griseus HH1 harboring afsA showed a similar level of enzyme activity , however, all the three protease activities sharply increased and the thiol protease activity was critically increased at the end of the fermentation. When a serine protease inhibitor, pefabloc SC, and metalloprotease inhibitor, EDTA, were applied to strain IFO 13350 to examine the in vivo effects of the protease inhibitors on the morpholofical differentiation, the formation of aerial meycelium and spores was delayed by two or three days.

• Journal of Life Science
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• 제9권2호
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• pp.9-14
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• 1999

Pseudomonas iodinum IFO 3558 adenosine deaminase(ADA) gene was cloned by the polymerase chain reaction and deduced the amino acid sequence of the enzyme. DNA sequence homology of Pseudomonas iodinum IFO 3558 ADA gene was compared to those of E. coli, human and mouse ADA genes. Unambiguous sequence from both strands of pM21 was obtained for the region believed to encode ADA. The sequence included a 804-nucleotide open reading frame, bounded on one end by sense primer and on the other end by two antisense primer. This open reading frame encodes a protein of 268 amino acids having a molecular weight of 29,448. The deduced amino acid sequence shows considerable similarity to those of E. coli, mouse and human ADA. Pseudomonas iodinum IFO 3558 nucleotide sequence shows 98.5% homology with that of the E. coli ADA sequence and 51.7% homology with that of the mouse ADA sequence and 52.5% homology with that of the human ADA sequence. The ADA protein sequence of Pseudomonas iodinum IFO 3558 shows 96.9% homology with that of the E. coli and 40.7% homology with that of the mouse and 41.8% homology with that of the human. The distance between two of the conserved elements, TVHAGE and SL(1)NTDDP has veen exactly conserved at 76 amino acids for all four ADAs. Two of the four conserved sequence elements shared among the four ADAs are also present in the yeast, rat, human (M), and Human(L) AMP deaminase. The SLSTDDP sequence differs only in the conservative substitution of a serine for an asparagine. A conserved cysteine with conserved spacing between these two regions is also found. Thus, sequence analysis of four ADAs and four AMP deaminases revealed the presence of a highly conserved sequence motif, SLN(S)TDDP, a conserved dipeptide, HA, and a conserved cysteine residue.

• Microbiology and Biotechnology Letters
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• 제4권4호
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• pp.166-178
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• 1976

Taxonomic study of 11 strains of Bacillus coagulans and 14 strains of 13 spccies of Bacillus by deoxyribonucleic acid (DNA)-DNA hybridization were conducted. Among the 11 strains of B. coagulans, 6 were isolated from soil and the rest were the authentic strains obtained from American Type culture collection (ATCC) or the Institute for Fermentation, Osaka (IFO). All strains were examined to confirm as they are expected species of B. coagulans by the methods of Cordon et al. according to Bergey's Manual (8th ed.). The intraspecific DNA homology indexes among the 11 strains of B. coagulans using strain ATCC 7050 as the standard ($^3$H labeled input DNA) showed 76％ or, more, respectively. These findings accorded well with the results of the conventional taxonomic study according to the Bergey's Manual. The interspecific DNA homology indexes between B. coagulant strain ATCC 7050 and the type cultures of B. subtilis (168), B. licheniformis (IFO 12107), B. pumilus (IFO 12110), B. firmus (ATCC 14575), B. lentus (ATCC 10840), B. circulans (ATCC 4513), B. macelans (ATCC 8244), B. polymyxa (ATCC 842), B. sphaericus (ATCC 14577), B. brevis (ATCC 8246, IFO 12334), B. laterosporus (ATCC 64), and B. pantothenticus (ATCC 14576) respectively, showed 2 to 4％, while that of between B. coagulans ATCC 7050 and Escherichia coli K-12 was less than 1 ％.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.984-988
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• 2003

The actinomycete strain KH-6l4 possessed strong antifungal activity, especially antagonistic to the rice blast fungus, Pyricularia oryzae. Diaminopimelic acid (DAP) type and morphological and physiological characteristics, examined by scanning electron microscopy (SEM), indicated that KH-614 belonged to the genus Streptomyces. Antifungal agent produced by this strain was found to be most active, when the strain was cultured in the presence of glucose, polypeptone, and yeast extract (PY) medium for 6 days at $27^{\circ}C$. Based on the spectral report data, MS and NMR, the antifungal agent was identified as cyclo(L-leucyl-L-prolyl). According to the antimicrobial activity test measured by minimal inhibitory concentration (MIC), the cyclo(1eu-pro) exhibited the activity against Candida albicans IAM 4905, Mucor ramannianus IAM6218, Rhizoctonia solani IFO 6218, Aspergilus fumigatus ATCC 42202, Glomerella cingulata IFO 9767, Trichophton mentagrophytes ATCC 18749, and Trichophyton rubrum ATCC 44766, the order of MIC values were 50, 12.5, 5, 50, 25, 5, $5\;\mu\textrm{g}/ml$, respectively. Specifically, cyclo(1eu-pro) was one of the most effective elements against Pyricularia oryzae IFO 5994 with the MIC value of $2.5\;\mu\textrm{g}/ml$, thus indicating that cyclo(leu-pro) is a potential antifungal agent.

• Journal of the Korean Society of Food Science and Nutrition
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• 제21권3호
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• pp.279-285
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• 1992

Cytidine deaminase (EC 3.5.4.5) from Aspergillus fumigatus IFO 5840, which was the first cytidine deaminase to be found in a mold, was fractionated with ammonium sulfate (35-60%). When the enzyme solution in 0.25M of Tris-HCI buffer (pH 7.2) was preincubated at $37^{\circ}C$ for 25min, the enzyme activity was reached to maximum state. The optimum pH and temperature for the enzyme activity were found to be 6.8 to 7.2 and near $37^{\circ}C$, respectively. The enzyme was stable in a pH 7.2 to 9.0, and was generally stable at 4$0^{\circ}C$, but after treating at 6$0^{\circ}C$ for 20min at the optimal pH, 17% of the enzyme activity was inactivated, and disappeared completely by treating at 1$0^{\circ}C$ for 25min. Activation energy (Ea) of fungal cytidine deaminase was calculated as 14.190 Kcal /mol by the Arrhenius plot, and temperate coeffient ($Q_{10}$ ) of the enzyme was calculated as 2.163.

• The Korean Journal of Food And Nutrition
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• 제10권1호
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• pp.53-59
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• 1997

In this study investigated the effect of cytosine deaminase activity from Aspergillus fumigatus IFO 5840 by cytosine analogues. The results were as follows. The enzyme was strongly inibited by 2-thiouracil, 2-thiocytosine, 6-azacytosine and 2-mercaptopyrimidine. The half inhibitory concentration(HIC) of 2-thiocytosine and 6-azacytosine on cytosine deaminase was 0.80mM and 1.15mM, respectively. The enzyme was inhibited at a certain level by addition of 2-thiocytosine immediately, but was maintained to some extend under the inhibited state by 6-azacytosine in proportion to reaction time. Regardless of kinds of substrate such as cytosine and 5-fluorocytosine, 2-thiocytosine and 6-azacytosine showed action as inhibitors, 2-thiocytosine inhibited cytosine deaminase activity about twice as strong as 6-azacytosine. The enzyme, when cytosine was used as a substrate, was revealed the pattern of competitive inhibition by 2-thiocytosine and 6-azacytosine, The ki value for these compounds was 4.5$\times$10-4M and 1.756$\times$10-3M, respectively. At this point, the Hill coefficient for cytosine, 2-thiocytosine and 6-azacytosine was 1.80, 1.81 and 2.45, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제32권5A호
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• pp.484-489
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• 2007

The main disadvantage of orthogonal frequency division multiplexing (OFDM) systems is its sensitivity to carrier frequency offset and timing offset. This paper proposes a simple way of improving the performance of the integer frequency offset (IFO) estimator in OFDM-based digital video broadcasting (DVB) system. By modifying the conventional maximum likelihood (ML) estimator to have multi-stage estimation strategy, IFO estimator is derived. Simulations indicate that the proposed IFO estimator works robustly with reduced computational burden when compared to ML estimator.

• Microbiology and Biotechnology Letters
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• 제22권3호
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• pp.266-270
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• 1994

A bacteriocin was isolated from the supernatant fluid of M17G broth culture of Lactococcus sp. HY 449 strain, which showed strong inhibitory activity against the growth of selective indicator strain, Lactobacillus fermentum IFO3023. When the bacteriocin wasa added to the growing indicator cells or cell suspensions, viable cells and optical density were density were decreased, indicating bacteriolytic mode of action. Electron microscopic observation of indicator cells treated with bacteriocin revealed apparent damages on the cell surface and eventual lysis of cell walls.