• Title/Summary/Keyword: transmembrane

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Enzyme Deactivation During Enzyme Recycling with Ultrafiltration Hollow Fibers (한외여과막을 이용한 효소재순환 시스템에서의 효소역가감소)

  • 김준석;정용섭홍석인
    • KSBB Journal
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    • v.11 no.3
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    • pp.347-352
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    • 1996
  • The enzyme deactivation in a membrane recycling system for the simultaneous saccharification and fermentation(SSF) was studied under various temperature and pressure. The optimum molecular weight cut off(MWCO) of the ultrafiltration membrane for recycling cellulase and ${\beta}$-glucosidase was 50,000. When the cellulase was recycled continuously through the membrane system, it was not deactivated. But the activity of ${\beta}$-glucosidase was decreased with an increase in operating temperature and transmembrane pressure. After 720 minutes at $42^{\circ}C$ and 24.8 psig , the activity of ${\beta}$-glucosidase was reduced by 35% of the initial activity. Such tendencies could be well explained by the results of highly induced shear at the fiber surface of membrane when temperature and transmembrane pressure became higher.

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Cytotoxicity of Vibrio vulnificus Cytolysin on Rat Neutrophils

  • Park, Kwang-Hyun;Rho, In-Whan;Park, Byung-Hyun;Kim, Jong-Suk;Kim, Hyung-Rho
    • BMB Reports
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    • v.32 no.3
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    • pp.273-278
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    • 1999
  • Cytolysin produced by Vibrio vulnificus has been known to be lethal to mice by increasing vascular permeability and neutrophil sequestration in the lung. In the present study, a cytotoxic mechanism of V. vulnificus cytolysin on the neutrophil was investigated. Cytolysin rapidly bound to neutrophils and induced cell death, as determined by the trypan blue exclusion test. V. vulnificus cytolysin caused the depletion of cellular ATP without the release of ATP or lactate dehydrogenase. Formation of transmembrane pores was evidenced by the rapid efflux of potassium and 2-deoxy-D-[$^3H$]glucose from cytolysin-treated neutrophils. It was further confirmed by the rapid flow of monovalent ions in the patch clamp of cytolysin-treated neutrophil membrane. The pore formation was accompanied by the oligomerization of cytolysin monomers on the neutrophil membrane as demonstrated by immunoblot, which exhibited a 210 kDa band corresponding to a tetramer of the native cytolysin of $M_r$ 51,000. These findings indicate that V. vulnificus cytolysin rapidly binds to the neutrophil membrane and oligomerizes to form small transmembrane pores, which induce the efflux of potassium and the depletion of cellular ATP leading to cell death without cytolysis.

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In Silico Sequence Analysis Reveals New Characteristics of Fungal NADPH Oxidase Genes

  • Detry, Nicolas;Choi, Jaeyoung;Kuo, Hsiao-Che;Asiegbu, Fred O.;Lee, Yong-Hwan
    • Mycobiology
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    • v.42 no.3
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    • pp.241-248
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    • 2014
  • NADPH oxidases (Noxes), transmembrane proteins found in most eukaryotic species, generate reactive oxygen species and are thereby involved in essential biological processes. However, the fact that genes encoding ferric reductases and ferric-chelate reductases share high sequence similarities and domains with Nox genes represents a challenge for bioinformatic approaches used to identify Nox-encoding genes. Further, most studies on fungal Nox genes have focused mainly on functionality, rather than sequence properties, and consequently clear differentiation among the various Nox isoforms has not been achieved. We conducted an extensive sequence analysis to identify putative Nox genes among 34 eukaryotes, including 28 fungal genomes and one Oomycota genome. Analyses were performed with respect to phylogeny, transmembrane helices, di-histidine distance and glycosylation. Our analyses indicate that the sequence properties of fungal Nox genes are different from those of human and plant Nox genes, thus providing novel insight that will enable more accurate identification and characterization of fungal Nox genes.

Electrical characteristics of voltage-dependent $Ca^{++}$ channel in rat chromaffin cell. (흰쥐 부신수질 세포에서 voltage-dependent $Ca^{++}$ 채널의 전기적 특성에 관한 연구)

  • Goo, Yong-Sook;Lee, Tae-Soo;Cha, Eun-Jong
    • Proceedings of the KOSOMBE Conference
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    • v.1994 no.05
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    • pp.142-145
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    • 1994
  • Calcium(Ca) ion plays an important role to trigger the secretion of important neurotransmitters. Since Ca ion flows into the cell thru the ion selective channel, the conductance of which depends on the transmembrane potential, the voltage-dependent characteristic of Ca ion channel is crucial to elucidate the stimulus-secretion coupling of exocytosis. The present study measured the Ca ion currents thru a whole-cell configuration patch at the transmembrane potential clamped at various desired levels in the rat chromaffin cell. The resultant current-voltage relationship was differentiated to obtain dynamic conductance at each clamped voltage. Based on these measured data, five numerical parameters were extracted to reveal electrical properties of Ca ion inflow process thru the voltage-gated channel. The present study can be applied to comparing the electrical characteristics of Ca channel under different experimental conditions. Also, further study is warranted to model the conformational changes of the channel molecules.

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Cloning and Characterization of DAP10 homologue gene from Olive Flounder, Paralichthys olivaceus

  • Park, Chan-Il;Kim, Mu-Chan;Hwang, Jee-Youn;Kim, Ki-Hyuk;Kim, Joo-Won
    • Journal of fish pathology
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    • v.19 no.3
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    • pp.227-233
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    • 2006
  • Olive flounder immunoreceptor DAP10 homologue cDNA was cloned from a peripheral blood lymphocytes (PBLs) cDNA library. The length of the olive flounder DAP10 cDNA is 473bp and it contains an open reading frame of 234bp. The predicted polypeptide sequence is 78 amino acids, consisting of a 22-amino acid leader, an 11-amino acid extracellular domain, a 21-amino acid transmembrane segment, and a 24-amino acid cytoplasmic domain. The amino acid sequence of olive flounder DAP10 has 56%, 50%, 32%, 31%, and 31% sequence identity with zebrafish DAP10, catfish DAP10, cattle DAP10, rat DAP10 and Monkey DAP10, respectively. Olive flounder DAP10 has a conserved aspartic acid in the transmembrane domain and a phophatidylinositol-3 kinase-binding site (YxxM/V) in the cytoplasmic region. Genomic organization reveals that olive flounder DAP10 comprises five exons and four introns. A phylogenetic analysis based on the deduced amino acid sequence grouped the olive flounder DAP10 with other species DAP10. In RT-PCR analysis, DAP10 transcripts were detected predominantly in PBLs, kidney, spleen and intestine.

Production of Exopolysaccharides by Lactococcus lactis subsp. cremoris MG1363 Expressing the eps Gene Clusters from Two Strains of Lactobacillus rhamnosus

  • Kang, Hye-Ji;LaPointe, Gisele
    • Microbiology and Biotechnology Letters
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    • v.46 no.2
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    • pp.91-101
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    • 2018
  • The aim of this study was to transfer the 18.5 kb gene clusters coding for 17 genes from Lactobacillus rhamnosus to Lactococcus lactis subsp. cremoris MG1363 in order to determine the effect of host on exopolysaccharide (EPS) production and to provide a model for studying the phosphorylation of proteins which are proposed to be involved in EPS polymerization. Lactobacillus rhamnosus RW-9595M and ATCC 9595 have 99% identical operons coding for EPS biosynthesis, produced different amounts of EPS (543 vs 108 mg/l). L. lactis subsp. cremoris MG1363 transformed with the operons from RW-9595M and ATCC 9595 respectively, produced 326 and 302 mg/l EPS in M17 containing 0.5% glucose. The tyrosine protein kinase transmembrane modulator (Wzd) was proposed to participate in regulating chain elongation of EPS polymers by interacting with the tyrosine protein kinase Wze. While Wzd was found in phosphorylated form in the presence of the phosphorylated kinase (Wze), no phosphorylated proteins were detected when all nine tyrosines of Wzd were mutated to phenylalanine. Lactococcus lactis subsp. cremoris could produce higher amounts of EPS than other EPS-producing lactococci when expressing genes from L. rhamnosus. Phosphorylated Wzd was essential for the phosphorylation of Wze when expressed in vivo.

Clinical Application of OXYREX Hollow Fiber Membrane Oxygenator (국산 막형 산화기 (OXYREX)의 체외순환 임상 성적 - 개심수술 40례 적용 -)

  • 김형묵
    • Journal of Chest Surgery
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    • v.23 no.6
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    • pp.1049-1056
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    • 1990
  • The OXYREX hollow fiber membrane oxygenator developed by joint work of KIST and Green Cross Medical company has been evaluated by experimental investigation and clinical application, In this oxygenator gas exchanges occur through small pores of 0.1pm size which are distributed on 70% of surface of polypropylene hollow fiber. The Oxyrex membrane oxygenator consists of 36 thousand hollow fibers and it has 3.3m2 of gas exchange surface. The Oxyrex membrane oxygenator has unique blood flow path: blood enters the oxygenator passes between the hollow fibers and exits through outlet ports, that provides low transmembrane pressure drop. In the animal experiment and in vitro investigations of Oxyrex oxygenator, it showed low transmembrane pressure difference, effective heat exchanger performance, stable gas transfer function and less blood trauma. The Oxyrex oxygenator been used from March, 1990, to October, 1990, in 40 patients undergoing open heart operations. In the clinical applications of Oxyrex, adequate oxygenation[PaO2, 283$\pm$70mmHg] and carbon dioxide removal[PaCO2, 27\ulcorner6mmHg]were maintained under the condition of FiO2: below 0.6, Hct; 25%, perfusion flow; 2.4 L/min, gas flow: 2.1 L/min. During maximum 365 minutes of cardiopulmonary bypass[CPB] time period, the Oxyrex oxygenator maintained stable condition of PaO2, PaCO2 respectively and it also kept low plasma hemoglobin level. The complement proteins C3 and CH50 were not significantly changed pre to post CPB. There were no complications related to the oxygenator during and after the CPB.

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EFFECT OF D-PROPRANOLOL ON TRANSMEMBRANE ACTION POTENTIAL OF CARDIAC PAPILLARY MUSCLE OF CAT (고양이 유두근의 활동전압에 미치는 d-propranolol의 영향)

  • Lee, Jong-Heun;Kim, Joong-Soo
    • The Journal of the Korean dental association
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    • v.16 no.7 s.110
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    • pp.531-536
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    • 1978
  • Adult cats were light anesthetized with ethyl ether and heart was removed fastly. cardiac papillary muscle was dissected from heart in organ bath con taining Tyrode solution saturated with 95% O₂+5% CO₂, and prepared papillary muscles were placed in Tyrode solution that was continuously circulated and gassed with 95% O₂+5% CO₂at 32℃. The isolated papillary muscle was stimulated continuously with platinum pin electrode at frequency of 15/min and 90/min by means of electric stimulator and transmembrane action potentials were recorded with microelectrdes on the oscilloscope. The drug used was d-propranolol and its concentration was 0.5, 1.5 and 5.0 mg/L. The results obtained were as follows: 1. D-propranolol increased the threshold voltage of papillary muscle and raised by average of 213.6% of control. 2. D-propranolol had no effect on duration of action potential. 3. Conduction time of isolated papillary muscle was increased by d-propranolol and its effect was prominent at frequency of 90/min. 4. the maximum upstroke velocity was decreased by d-propranolol and its effect was dose-depndent decrease.

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Insight into influence of iron addition in membrane bioreactor on gel layer fouling

  • Zhang, Haifeng;Lu, Xin;Yu, Haihuan;Song, Lianfa
    • Membrane and Water Treatment
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    • v.8 no.6
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    • pp.543-551
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    • 2017
  • Membrane fouling in membrane bioreactor (MBR) remains a primary challenge for its wider application. The focus of this study to investigate the influence of iron distribution in activated sludge on gel layer fouling in MBR. Significant reduction in the transmembrane pressure (TMP) rise rates was observed in the presence of iron as result of retarding the gel layer formation time. The spatial distribution of iron had a significant impact on the stratification structure of extracellular polymeric substances (EPS) fractions, such as proteins (PN) and polysaccharides (PS). A mitigation of PN or PS from the supernatant to the EPS inner layers was observed in the presence of iron. Compared with the control reactor, the reduction in PN and PS of the supernatant and lower PN/PS rates of the LB-EPS were beneficial to decrease the membrane fouling potential during the gel layer formation. Consequently, the iron addition managed to control gel layer fouling could be a useful strategy in MBR.

Interferon Induced Transmembrane Protein-1 Gene Expression is a Biomarker for Early Detection of Invasive Potential of Oral Squamous Cell Carcinomas

  • Ramanathan, Arvind
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.4
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    • pp.2297-2299
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    • 2016
  • Background: Early detection of malignant transformation with expression biomarkers has significant potential to improve the survival rate of patients as such biomarkers enable prediction of progression and assess sensitivity to chemotherapy. The expression of interferon inducible transmembrane protein 1 (IFITM1) has been associated with early invasion events in several carcinomas, including head and neck cancers, and hence has been proposed as a novel candidate biomarker. As the incidence of oral squamous cell carcinoma (OSCC) is highest in the Indian population, we sought to investigate: 1) the expression pattern of IFITM1 in OSCC tissue samples obtained from Indian patients of Dravidian origin; and 2) the possibility of using IFITM1 expression as a potential biomarker. Materials and Methods: Total RNA extracted from thirty eight OSCC biopsy samples was subjected to semi-quantitative RT-PCR with IFITM1 and GAPDH specific primers. Results: Of the thirty eight OSCC samples that were analyzed, IFITM1 overexpression was identified in fifteen (39%). Seven expressed a low level, while the remainder expressed high level of IFITM1. Conclusions: The overexpression of IFITM1 in OSCC samples indicates that IFITM1 may be explored for the possibility of use as a high confidence diagnostic biomarker in oral cancers. To the best of our knowledge, this is the first time that IFITM1 overexpression is being reported in Indian OSCC samples.