• Title/Summary/Keyword: acid-resistance

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Probiotic properties and safety assessment of lactic acid bacteria isolated from salt-fermented anchovy (멸치 젓갈로부터 분리된 젖산세균의 프로바이오틱 특성 및 안전성 평가)

  • Lim, Eun-Seo;Kim, Young-Mog;Lee, Eun-Woo
    • Korean Journal of Food Science and Technology
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    • v.48 no.4
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    • pp.306-316
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    • 2016
  • This study was conducted to evaluate the functional characteristics and safety properties of lactic acid bacteria isolated from salt-fermented anchovy, a putative probiotic candidate. The following isolates were identified by biochemical profiles, carbohydrate fermentation patterns, and 16S rRNA sequencing: Enterococcus faecium AJ06, Leuconostoc mesenteroides AJ13, Pediococcus halophilus AJ22, Lactobacillus sakei AJ29, and Pediococcus pentosaceus AJ35. The strains AJ06, AJ22, AJ29 exhibited high tolerance to simulated gastric and intestinal juices and were able to produce bile salt hydrolase on MRS agar plates supplemented with taurocholic acid and/or taurodeoxycholic acid. The strains AJ22 and AJ29, which demonstrated high adherence to Caco-2 cells and resistance to various antibiotics, effectively inhibited the growth of food-borne pathogens by the production of antimicrobial substances. These strains did not show ${\alpha}-$ or ${\beta}$-haemolysis on blood agar. Furthermore, biogenic amines in MRS broth containing the precursor amino acids were not mutagenic in Salmonella Typhimurium TA98 and TA100.

Pervaporation of Fluoroethano1 and Methacrylic Acid Aqueous Solution Through New Acid-resistant Poly(vinyl alcohol) Membranes (새로운 내산성 PVA가교막을 이용한 불화에탄을 수용액과 메타크릴산 수용액의 투과증발분리)

  • Lee Soo-Bok;Ahn Sang-Man;Chang Bong-Jun;Kim Jeong-Hoon;Lee Yong-Taek
    • Membrane Journal
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    • v.15 no.3
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    • pp.206-212
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    • 2005
  • Acid-resistant poly(vinyl alcohol) (PVA) membranes connected with ethylene and ether groups were prepared via a thermal crosslinking reaction by varying the ratio of PVA to ethylene glycol diglycidyl ether (EGDE). The crosslinked membranes were characterized using FT-IR and swelling tests, respectively. Pervaporation behaviors with the PVA membranes were investigated for aqueous TFEA (2,2,2-trifluoroethanol) as a function of EGDE content and operating temperature. The pervaporation properties far MA (methacrylic acid)/water mixture were also carried out with the optimized PVA membrane. The PVA membranes prepared with EGDE showed more excellent acid-resistance than those crosslinked with gluaraldehyde. The membranes showed high permeation fluxes of 0.1 and $0.3\;km^2h$ and high separation factors of 100 and 900 in the $96\;wt\%$ TFEA and MA aqueous fred mixtures at high temperature above $80^{\circ}C$, respectively. These confirmed theses membranes could be used in esterification membrane reactor process for the production of 2,2,2-trifluoroethylmetacrylate (TFEMA).

Effects of Surface Modification of the Membrane in the Ultrafiltration of Waste Water

  • Cho Dong Lyun;Kim Sung-Hyun;Huh Yang Il;Kim Doman;Cho Sung Yong;Kim Byung-Hoon
    • Macromolecular Research
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    • v.12 no.6
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    • pp.553-558
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    • 2004
  • An ultrafiltration membrane (polyethersulfone, PM 10) was surface-modified by treating it with low-tem­perature plasmas of oxygen, acrylic acid (AA), acetylene, diaminocyolohexane (DACH), and hexamethyldisiloxane (HMDSO). The effects that these modifications have on the filtration efficiency of a membrane in waste water treat­ment were investigated. The oxygen, AA, and DACH plasma-treated membranes became more hydrophilic. The water contact angles ranged from < $10^{\circ}\;to\;55^{\circ}$ depending on the type of plasma and the treatment conditions. The oxygen plasma-treated membranes displayed a higher initial flux $(312-429\%),$ but lower rejection $(6-91\%),$ than did an untreated membrane. The AA plasma-treated membranes displayed lower or higher initial flux $(42-156\%),$ depending upon the treatment conditions, but higher rejection $(224-295\%)$ in all cases. The DACH plasma-treated membranes displayed lower initial flux. All of them, especially the AA plasma-treated membrane, displayed improved fouling resistance with either a slower or no flux decline. Acetylene and HMDSO plasma-treated membranes became more hydrophobic and displayed both lower initial flux and lower fouling resistance.

Effect of Coated Polypyrrole Content on the Properties of Polypyrrole Coated Fabrics (폴리피롤 코팅 직물의 성질에 미치는 폴리피롤 함량의 영향)

  • Son, Seong-Ho;Lee, Young-Hee;Lee, Dong-Jin;Kim, Sung Yeol;Kim, Han-Do
    • Textile Coloration and Finishing
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    • v.28 no.2
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    • pp.92-100
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    • 2016
  • To chemically prepare polypyrrole(pPy) coated fabrics(silk, cotton and nylon fabrics), the fabrics were first soaked in 0.4M oxidant $FeCl_3$/0.06M dopant anthraquinone-2-sulfonic acid solution for 5min at room temperature, and subsequently soaked in a 0.4M monomer pyrrole aqueous solution for 5min at room temperature. The content(wt%) of coated pPy in the coated fabrics was controlled by the number of treatments(these two steps). This study examined the effect of the number of treatments/pPy content on the sheet resistance, mechanical/bending properties and color behaviors of pPy coated fabrics. The coated pPy content, sheet resistance(${\Omega}$/square) and color strength(K/S) of pPy coated fabrics increased sharply with increasing number of treatments up to 20 times, while the increase slowed down afterward. The tensile strength, elongation at break and lightness($L^*$) decreased with increasing number of treatments. The tensile modulus and bending rigidity of coated fabrics increased significantly with increasing number of treatments/coated pPy content. This indicated that the flexibility of coated fabrics decreased considerably.

Associations of Polymorphisms in the Mx1 Gene with Immunity Traits in Large WhitexMeishan F2 Offspring

  • Li, X.L.;He, W.L.;Deng, C.Y.;Xiong, Y.Z.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.11
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    • pp.1651-1654
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    • 2007
  • The mouse myxovirus resistance protein 1 (Mx1) is known to be sufficient to confer resistance to influenza viruses, and the gene encoding Mx1 is, therefore, an interesting candidate gene for disease resistance in farm animals. The porcine Mx1 gene has already been identified and characterized based on its homology with mouse Mx1; the full-length coding region of the pig Mx1 gene spans 2,545 bp (M65087) and is organized into 17 exons compared with the human ortholog mRNA. In this study, the exons 9, 10 and 11 and introns 6 and 9 of the porcine Mx1 gene were cloned and sequenced. Two SNPs were identified in exons 9, 10 and 11 but none of the SNPs led to an amino acid exchange, and the other eleven variants were detected in introns 6 and 9, respectively. Differences in allele frequency between Meishan and other pig breeds were observed within intron 6, of which an $A{\rightarrow}G$ substitution at position 371 was detected as an SnaBI PCR-RFLP. The association analysis using the Large White${\times}$Meishan $F_2$ offspring suggested that the Mx1 genotype was associated with variation in several immunity traits that are of interest in pig breeding. However, further investigations in more populations are needed to confirm the above result.

The coat protein of Turnip crinkle virus is required a full-length to maintain suppressing activity to RNA silencing but no relation with eliciting resistance by N-terminal region in Arabidopsis.

  • Park, Chang-Won;Feng Qu;Tao Ren;T. Jack Morris
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.76.1-76
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    • 2003
  • The coat protein (CP) of Turnip crinkle virus (TCV) is organized into 3 distinct domains, R domain (RNA-binding) connected by an arm, 5 domain and P domain. We have previously shown that the CP of TCV strongly suppresses RNA silencing, and have mapped N-terminal R domain of which is also the elicitor of resistance response in the Arabidopsis ecotype Di-17 carrying the HRT resistance gene. In order to map the region in the TCV CP that is responsible for silencing suppression, a series of CP mutants were constructed, transformed into Agrobacterium, coinfiltrated either with HC-Pro (the helper component proteinase of tobacco etch potyvirus) known as a suppressor of PTGS or GFP constructs into leaves of Nicotiana benthmiana expressing GFP transgenically. In the presence of HC-Pro, all CP mutants were well protected, accumulating mutant CP mRNAs and their proteins even 5 days post-infiltration (DPI). In the presence of GFP, some mutant constructs which showed the accumulation of CP mutants and GFP mRNAs at early stage but eventually degraded at 5 DPI. Only a mutant which carrying 4 amino acid deletion of R domain was tolerable to maintain suppressing activity, suggesting that the suppressing activity is not directly related with the eliciting activity. A transient assay also revealed that the mutants synthesized their proteins, suggesting that a full length of CP sequences and its intact structure are required to stabilize CP, which suppresses the RNA silencing.

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Resistant Activity to Hydrogen Peroxide of Lactobacillus spp., Bifidobacterium spp., Bacillus coagulans and Hydrogen Peroxide Generation Capability of Lactobacillus spp. (Lactobacillus spp., Bifidobacterium spp. 및 Bacillus coagulans의 과산화수소 저항성과 과산화수소 생성 능력)

  • Lee, Jong-Hyeok;Yoon, Yeong-Ho
    • Journal of Dairy Science and Biotechnology
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    • v.22 no.2
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    • pp.107-112
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    • 2004
  • Studies on the resistance of Lactobacillus ssp., Bifidobacterium spp. and Bacillus coagulans to hydrogen peroxide were conducted by determination of the viable cells after the test cells in 2mM hydrogen peroxide solution for a predetermined time; L. acidophilus CU4111 and L. casei CU4114 were most resistant to the hydrogen peroxide among the fifteen test lactobacilli strains, whereas L. brevis Cu4206 was the strain which was the most susceptible to hydrogen peroxide. Bifidobacterium longum Cu4131 was one of the resistant strains. A prominant tendency found out that Bacillus coagulans possessed a strong resistance to hydrogen peroxide. The results of level of hydrogen peroxide determination in the cell extracts showed all the test strains contained hydrogen peroxide in the cytoplasm, the amount varied depending on the strain and species of lactic acid bacteria. Bifidobacterium bifidum CU 4134 and L. casei CU 4114 were potent hydrogen peroxide producer strain.

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Antibacterial properties of quinolones

  • Yoshida, Hiroaki
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1997.04a
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    • pp.40-47
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    • 1997
  • New quinolones generally have a broad antibacterial spectrum against gram-positive, gram-negative, glucose-nonfermenting and anaerobic bacteria. Some of newly developed quinolones have potent activities against S. aureus including MRSA, S.pneumoniae including PRSP, B. fragilis, chlamydiae, mycoplasmas and mycobacteria as well, and show good activities against various strains resistant to antibacterial agents of other classes. Quinolones display postantibiotic effects in vitro and are bactericidal at concentrations similar to or twice that of the minimum inhibitory concentrations (MICs) for susceptible pathogens. In experimental murine infection models including systemic infections with various pathogens such as S. aureus, S. pyogenes, S. pneumoniae, E. coli and P. aeruginosa, quinolones have shown good oral efficacy as well as parenteral efficacy. Good oral absorption and good tissue penetration of quinolones account for good therapeutic effects in clinical settings. The target of quinolones are two structurally related type II topoisomerases, DNA gyrase and DNA topoisomerase IV. Quinolones are shown to stabilize the ternary quinolone-gyrase-DNA complex and inhibit the religation of the cleaved double-stranded DNA. Bacteria can acquire resistance to quinolones by mutations of these target enzymes. Mutation sites and amino acid changes in DNA gyrase and DNA topoisomerase IV are similar in the organisms examined, suggesting that the mechanism of quinolone resistance in the target enzymes is essentially the same among various organisms. Quinolones act on both the target enzymes to different degrees depending on the organisms or agents tested, and bacteria become highly resistant to quinolones in a step-wise fashion. Incomplete cross-resistance among quinolones in some strains of E. coli and S. aureus suggests the possibility of finding quinolones active against quinolone-resistant strains which are prevailing now. To find such quinolones, the potency toward two target enzymes and the membrane permeability including influx and/or efflux systems should be taken into account.

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Anti-malarial Drug Design by Targeting Apicoplasts: New Perspectives

  • Mukherjee, Avinaba;Sadhukhan, Gobinda Chandra
    • Journal of Pharmacopuncture
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    • v.19 no.1
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    • pp.7-15
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    • 2016
  • Objectives: Malaria has been a major global health problem in recent times with increasing mortality. Current treatment methods include parasiticidal drugs and vaccinations. However, resistance among malarial parasites to the existing drugs has emerged as a significant area of concern in anti-malarial drug design. Researchers are now desperately looking for new targets to develop anti-malarials drug which is more target specific. Malarial parasites harbor a plastid-like organelle known as the 'apicoplast', which is thought to provide an exciting new outlook for the development of drugs to be used against the parasite. This review elaborates on the current state of development of novel compounds targeted againstemerging malaria parasites. Methods: The apicoplast, originates by an endosymbiotic process, contains a range of metabolic pathways and housekeeping processes that differ from the host body and thereby presents ideal strategies for anti-malarial drug therapy. Drugs are designed by targeting the unique mechanism of the apicoplasts genetic machinery. Several anabolic and catabolic processes, like fatty acid, isopenetyl diphosphate and heme synthess in this organelle, have also been targeted by drugs. Results: Apicoplasts offer exciting opportunities for the development of malarial treatment specific drugs have been found to act by disrupting this organelle's function, which wouldimpede the survival of the parasite. Conclusion: Recent advanced drugs, their modes of action, and their advantages in the treatment of malaria by using apicoplasts as a target are discussed in this review which thought to be very useful in desigining anti-malarial drugs. Targetting the genetic machinery of apicoplast shows a great advantange regarding anti-malarial drug design. Critical knowledge of these new drugs would give a healthier understanding for deciphering the mechanism of action of anti-malarial drugs when targeting apicoplasts to overcome drug resistance.

Effect of current density, temperature and electrolyte concentration on Composition of Zn-Ni Electrodeposits (Zn-Ni도금의 합금화에 미치는 전류밀도, 온도와 전해액농도의 영향)

  • Kang, Soo Young
    • Journal of the Korea Convergence Society
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    • v.8 no.11
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    • pp.307-312
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    • 2017
  • In the industry, galvanizing using the principle of sacrificial anode is used Zn-Ni alloy plating was developed as one of the measures to increase the corrosion resistance rather than pure zinc plating. The alloy plating layer has a corrosion resistance of 4-5 times that of the pure zinc plating layer, so that it is applied to automotive parts requiring high corrosion resistance even though the plating cost is high. The amount of Zn-Ni alloy plating solution is a sulfuric acid bath, a chlorinated bath, an alkali bath, and an ammonia bath. Here, the influence of the electrolytic conditions on the composition of the alloy plating in the chloride bath was investigated. The results are explained by the cathode overvoltage and the diffusion coefficient. In general, as the overvoltage of the cathode increases, the concentration polarization becomes more important than the activation polarization. The concentration polarization is determined by element diffusion in the diffusion layer. That is, as the overvoltage of the cathode increases, the Zn content having a large diffusion coefficient increases.