• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1377-1378
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• 2010

• Journal of Microbiology
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• v.39 no.1
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• pp.74-78
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• 2001

The transcription of the chitin synthase genes (chss) was cell cycle-regulated in Aspergillus nidulans and the expression pattern was classified into two groups. Group one, containing chsA and chsC, showed decreasing transcription level upon entry into the S-phase and no further variation during the remainder of the cell cycle. However, group two, containing chsB, chsD, and csmA showed a sharp decrease of mRNA level upon entry into the G2-phase and an increase during the M-phase. Our results suggested that the chss, belonging to same group with the similar expression pattern during the cell cycle are functionally linked and that chsD may play a role in hyphal growth and development in A. nidulans.

• Mycobiology
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• v.29 no.4
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• pp.179-182
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• 2001

Chitin synthases(UDP-N-acetyl-D-glucosamine: chitin 4-$\beta$-N-acetyl-D-glucosaminyl transferase, EC 2.4.1.16) catalyze the synthesis of chitin from UDP-N-acetyl-D-glucosamine. Two zymogenic type of chitin synthase gene(TmCHS1 and TmCHS2) were amplified and its nucleotide sequences were determined. By the amino acid comparison and UPGMA tree grouping, TmChs1 and TmChs2 were classified as class II and class IV chitin synthases respectively. The class II type TmChs1 was grouped with others of Agaricales ectomycorrhizal mushroom. Additionally the phylogenetic tree was well adapted to Hymenomycete previously classified by morphological and physiological characteristics.

• Applied Biological Chemistry
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• v.27
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• pp.29-46
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• 1984

To utilize several species of hard wood as raw materials of feed products, fermentation characteristics of cellulosic substrates to single cell protein was investigated, and results were summarized as follows. Among the microorganisms investigated, Tricoderma viride was selected as one of the most cellulolytic. Mixed culture of fungi did not show a synergistic effect on cellulose degradation. When the fungi were cultured at $28^{\circ}C$ for 7 days in a medium containing wheat bran 25 g, cellulose 0.25 g, proteose peptone 0.025 g and tween 800.025 g, cellulotic activities on carboxy methyl cellulose and filter paper reached maximum at 12 hr. The alkali treatment resulted in increased degradation of substrate from 13 to 18% when treated with enzymes for 12h, and reducing sugar formation increased with decreased size of substrates. Glucose was a very good feedback inhibitor of the enzyme from T.viride than that of xylose. When the substrate was rehydrolyzed, hydrolysis rate was 31% to reducing sugars within 12 hr. Quantative anlysis with HPLC showed the ratio of glucose to xylose in sugar syrups as 1.77 to 1. For the purpose of producing cellulosic-single cell protein from the sawdust of mulberry tree, 15 strains of xylose-assimilating yeast were isolated from 42 samples of rotten woods and compost soils and examined for their ability to utilize xylose. Then three strains were selected by their strong xylose-assimilating activities. The cultivative condition, the growth characteristics, and protein and nucleic acid productivities of three strains were investigated. The results obtained were, 1. Wood hydrolysate of mulberry tree was assimilated by 5 strains of CHS-2, CHS-3, ST-40, CHS-12 and CHS-13. 2. The optimum initial pH and temperature for the growth of strain CHS-13 were 4.4 and $30^{\circ}C$. 3. The specific growth rate of strain CHS-13 was $0.23h^{-1}$ and generation time was 3.01 hrs at the optimum condition. 4. CHS-13 strain assimilated 81 % of sugar in wood hydrolysate. 5. CHS-13 strain was identified as Candida guilliermondii var. guilliermondii 6. When the CHS-13 strain was cultured in the wood hydrolysate containing yeast extract, L-protein content was increased with yeast extract concentration. 7. The L-protein and nucleic acid yields from wood hydrolysate were 0.73 mg/ml and $4.92{\times}10^{-2}\;mg/ml$ respectively. 8. An optimal nucleic acid content of CHS-13 strain was observed in the medium containing 0.2% of yeast extract.

• Journal of Microbiology
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• v.38 no.4
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• pp.230-238
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• 2000

Class III chitin synthases in filamentous fungi are important for hyphal growth and differentiation of several filamentous fungi. A genomic clone containing the full gene encoding Chs4, a class III chitin synthase in Penicillium chrysogenum, was cloned by PCR screening and colony hybridization from the genomic library. Nucleotide sequence analysis and transcript mapping of chs4 revealed an open reading frame (ORF) that consisted of 5 exons and 4 introns and encoded a putative protein of 915 amino acids. Nucleotide sequence analysis of the 5'flanking region of the ORF revealed a potential TATA box and several binding sites for transcription activators. The putative transcription initiation site at -716 position was identified by primer extension and the expression of the chs4 during the vegetative growth was confirmed by Northern blot analysis. Amino acid sequence analysis of the Chs4 revealed at least 5 transmembrane helices and several sites for past-transnational modifications. Comparison of the amino acid sequence of Chs4 with those of other fungi showed a close relationship between P chrysogenum and genus Aspergillus.

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.159-163
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• 2013

Objective : Cerebral hyperperfusion syndrome (CHS) is a serious complication after carotid endarterectomy (CEA). However, the prevalence of CHS has decreased as techniques have improved. This study evaluates the role of strict blood pressure (BP) control for the prevention of CHS. Methods : All 18 patients who received CEA from February 2009 through November 2012 were retrospectively reviewed. All patients were routinely managed in an intensive care unit by a same protocol. The cerebral perfusion state was evaluated on the basis of the regional cerebral blood flow (rCBF) study by perfusion computed tomography (pCT) and mean velocity by transcranial doppler (TCD). BP was strictly controlled (<140/90 mm Hg) for 7 days. When either post-CEA hyperperfusion (>100% increase in the rCBF by pCT or in the mean velocity by TCD compared with preoperative values) or CHS was detected, BP was maintained below 120/80 mm Hg. Results : TCD and pCT data on the patients were analyzed. Ipsilateral rCBF was significantly increased after CEA in the pCT (p=0.049). Post-CEA hyperperfusion was observed in 3 patients (18.7%) in the pCT and 2 patients (12.5%) in the TCD study. No patients developed clinical CHS for one month after CEA. Furthermore, no patients developed additional neurological deficits related to postoperative cerebrovascular complications. Conclusion : Intensive care with strict BP control (<140/90 mm Hg) achieved a low prevalence of post-CEA hyperperfusion and prevented CHS. This study suggests that intensive care with strict BP control can prevent the prevalence of post-CEA CHS.

• The Journal of Pediatrics of Korean Medicine
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• v.20 no.1
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• pp.109-135
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• 2006

Objective : In the present study, the author tried to investigate whether six oriental medical prescriptions named gamisingitang (SGT), gamijungtang (IJT), gamicheongpyetang (CPT), galhwengchihyosan (CHS), chwiyeontong (CYT), sigyoungcheongpyetang (SCPT) significantly affect mucin release from cultured hamster tracheal surface epithelial (HTSE) cells. Methode : Confluent HTSE cells were inetabolically radiolabeled with $^{3}H-glucosamine$ for 24 hrs and chased for 30 min in the presence of drugs aforementioned, respectively, to assess the effect of each drug on $^{3}H-mucin$ release. Possible cytotoxicities of effective drugs were assessed by measuring lactate dehydrogenase(LDH) release. Additionally, total elution profiles of control spent media and treatment sample (CPT, CHS, SCPT and CYT) through Sepharose CL-4B column were analysed and effect of CPT, CHS and CYT on MUC5AC mRNA expression in cultured HTSE cells were invsetigated. Results : (1) SGT and IJT did not affect mucin release without cytotoxicity; (2) CPT, SCPT and CHS significantly stimulated mucin release from cultured HTSE cells, with significant cytotoxicity; (4) CPT, CHS, SCPT and CYT chiefly affected the 'mucin' release and did not affect significantly the release of the releasable glycoproteins with less molecular weight than mucin. This result suggests that the four herbal prescriptions specifically affect the release of mucin ; (5) CTP and CHS did not significantly affect the expression levels of MUC 5AC mRNA, however, CYT significantly inhibit the expression levels of MUC 5AC mRNA. Conclusion : CYT can decrease the synthesis of mucin at gene level in cultured HTSE cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.1
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• pp.69-75
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• 2006

In the present study, the author tried to investigate whether four oriental medical prescriptions named, jawan-chihyosan (CHS), gwaru-jisiltang (GJT), and several single compounds, kaempferol, coumarin, betaine and ursolic acid significantly affect mucin release from cultured hamster tracheal surface epithelial (HTSE) cells. Confluent HTSE cells were metabolically radiolabeled with 3H-glucosamine for 24 hrs and chased for 30 min in the presence of CHS, GJT, kaempferol, coumarin, betaine and ursolic acid, respectively, to assess the effect of each agent on 3H-mucin release. Possible cytotoxicities of each agent were assessed by measuring lactate dehydrogenase(LDH) release. Additionally, total elution profiles of control spent media and treatment sample (CHS and GJT) through Sepharose CL-4B column were analysed and effect of CHS and GJT on MUC5AC mRNA expression in cultured HTSE cells were investigated. The results were as follows : (1) CHS and GJT significantly stimulated mucin release from cultured HTSE cells, with significant cytotoxicity , (2) CHS and GJT chiefly stimulated the 'mucin' release and did not affect significantly the release of the other releasable glycoproteins with less molecular weight than mucin. This result suggests that the three herbal prescriptions specifically stimulate the release of mucin ; (3) CHS and GJT significantly increased the expression levels of MUC 5AC mRNA. This result suggests that the three herbal prescriptions can affect the synthesis of mucin at gene level in cultured HTSE cells ; (4) Kaempferol and coumarin did not affect mucin release, however, betaine and ursolic acid stimulated mucin release. All the agents did not show significant cytotoxicity. We suggest that the effects of CHS and GJT, betaine and ursolic acid should be further investigated and it is of great value to find, from oriental medical prescriptions, novel agents which have the effective expectorant or mucoregulative effect on mucin secretion from airway goblet cells.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3302-3320
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• 2014

An allocation of sensing and reporting times is proposed to improve the sensing performance by scheduling them in an efficient way for cognitive radio networks with cluster-based cooperative spectrum sensing. In the conventional cooperative sensing scheme, all secondary users (SUs) detect the primary user (PU) signal to check the availability of the spectrum during a fixed sensing time slot. The sensing results from the SUs are reported to cluster heads (CHs) during the reporting time slots of the SUs and the CHs forward them to a fusion center (FC) during the reporting time slots of the CHs through the common control channels for the global decision, respectively. However, the delivery of the local decision from SUs and CHs to a CH and FC requires a time which does not contribute to the performance of spectrum sensing and system throughput. In this paper, a super-allocation technique, which merges reporting time slots of SUs and CHs to sensing time slots of SUs by re-scheduling the reporting time slots, has been proposed to sense the spectrum more accurately. In this regard, SUs in each cluster can obtain a longer sensing duration depending on their reporting order and their clusters except for the first SU belonged to the first cluster. The proposed scheme, therefore, can achieve better sensing performance under -28 dB to -10 dB environments and will thus reduce reporting overhead.

• Journal of Communications and Networks
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• v.12 no.2
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• pp.122-129
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• 2010

Energy conservation is one of the most important issues for evaluating the performance of wireless sensor network (WSN) applications. Generally speaking, hierarchical clustering protocols such as LEACH, LEACH-C, EEEAC, and BCDCP are more efficient in energy conservation than flat routing protocols. However, these typical protocols still have drawbacks of unequal and high energy depletion in cluster heads (CHs) due to the different transmission distance from each CH to the base station (BS). In order to minimize the energy consumption and increase the network lifetime, we propose a new hierarchical routing protocol, distance aware intelligent clustering protocol (DAIC), with the key concept of dividing the network into tiers and selecting the high energy CHs at the nearest distance from the BS. We have observed that a considerable amount of energy can be conserved by selecting CHs at the nearest distance from the BS. Also, the number of CHs is computed dynamically to avoid the selection of unnecessarily large number of CHs in the network. Our simulation results showed that the proposed DAIC outperforms LEACH and LEACH-C by 63.28% and 36.27% in energy conservation respectively. The distance aware CH selection method adopted in the proposed DAIC protocol can also be adapted to other hierarchical clustering protocols for the higher energy efficiency.