• 제목/요약/키워드: biological stability

검색결과 841건 처리시간 0.029초

Antibacterial Mode of Action of Cinnamomum verum Bark Essential Oil, Alone and in Combination with Piperacillin, Against a Multi-Drug-Resistant Escherichia coli Strain

  • Yap, Polly Soo Xi;Krishnan, Thiba;Chan, Kok-Gan;Lim, Swee Hua Erin
    • Journal of Microbiology and Biotechnology
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    • 제25권8호
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    • pp.1299-1306
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    • 2015
  • This study aims to investigate the mechanism of action of the cinnamon bark essential oil (CB), when used singly and also in combination with piperacillin, for its antimicrobial and synergistic activity against beta-lactamase TEM-1 plasmid-conferred Escherichia coli J53 R1. Viable count of bacteria for this combination of essential oil and antibiotic showed a complete killing profile at 20 h and further confirmed its synergistic effect by reducing the bacteria cell numbers. Analysis on the stability of treated cultures for cell membrane permeability by CB when tested against sodium dodecyl sulfate revealed that the bacterial cell membrane was disrupted by the essential oil. Scanning electron microscopy observation and bacterial surface charge measurement also revealed that CB causes irreversible membrane damage and reduces the bacterial surface charge. In addition, bioluminescence expression of Escherichia coli [pSB1075] and E. coli [pSB401] by CB showed reduction, indicating the possibility of the presence of quorum sensing (QS) inhibitors. Gas-chromatography and mass spectrometry of the essential oil of Cinnamomum verum showed that trans-cinnamaldehyde (72.81%), benzyl alcohol (12.5%), and eugenol (6.57%) were the major components in the essential oil. From this study, CB has the potential to reverse E. coli J53 R1 resistance to piperacillin through two pathways; modification in the permeability of the outer membrane or bacterial QS inhibition.

Streptomyces sp. S56 endoinulase의 고정화 및 성질 (Immobilization and properties of Streptomyces sp. S56 endoinulase)

  • 김수일;장호진
    • Applied Biological Chemistry
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    • 제35권5호
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    • pp.410-414
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    • 1992
  • Streptomyces sp. S56 endoinulase를 DEAE-cellulose에 고정화하였고 고정화 효소의 일반 특성을 유리효소와 비교하였으며 돼지감자 추출물 및 inulin의 고정화 효소에 의한 가수분해 조건을 조사하였다. 고정화 효소의 최적 작용 pH는 $4.5{\sim}5.5$로 유리효소보다 효소작용 pH가 산성으로 이동되었으며 작용 안정 pH는 6으로 유리효소와 동일하나 전반적으로 고정화에 의하여 pH 안정성은 저하되었다. 반면 온도 안정성은 고정화에 의하여 크게 증가되어 $50^{\circ}C$, 1시간 처리에서도 70%, 이상의 활성을 가지고 있었으며 또한 최적온도도 유리효소보다 높게 나타났다. 기질친화성은 고정화에 의하여 5배 정도 낮아지나 반응 최고속도는 반대로 2배 이상 증가되었다. 돼지감자 추출물 및 inulin은 고정화 효소에 의하여 48시간 내에 각각 총당의 63%, 78%를 가수분해, fructose 및 inulobiose를 주로 생산하였다.

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Cellulase에 관(關)한 연구(硏究) -(제1보(第一報)) Cellulase 생성균(生成菌)의 분리(分離)와 조효소(粗酵素)의 제성질(諸性質)- (Studies on Cellulase -Part 1. Isolation of Cellulase Forming Microorganisms and the Properties of Crude Enzymes-)

  • 정동효
    • Applied Biological Chemistry
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    • 제11권
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    • pp.109-117
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    • 1969
  • 분뇨처리장(糞尿處理場)에서 400여(餘) 균주(菌株)를 분리(分離)한 결과(結果) 그중(中) 두 균주(菌株)가 cellulase생성(生成)이 강(强)하였다. 이 균주(菌株)는 진탕배양(振湯培養)으로 cellulase를 많이 생성(生成)하였으며 이들 효소(酵素)의 성질(性質)은 다음과 같다. 1. 최적(最適) pH는 4.0에서 5.5 범위이다. 2. 안전(安全) pH는 3.5에서 6.5 범위이다. 3. 최적온도(最適溫度)는 $40^{\circ}C$에서 $45^{\circ}C$ 이다. 4. 열안전성(熱安全性)은 $50^{\circ}C$ 이하이며 $70^{\circ}C$에서 거의 불활성화(不活性化) 된다. 5. 투석효소(透析酵素)는 $Mn^{2+}\;Co^{2+}$로 활성화되며 $Hg^{2+}$는 강한 조해제(阻害劑)이다.

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고정화 글루코아밀라제의 성질과 응용 (Characteristics and Applications of Immobilized Glucoamylase)

  • 조성환;김재욱
    • Applied Biological Chemistry
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    • 제28권4호
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    • pp.233-238
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    • 1985
  • Glucoamylase를 $ZrO_2$로 피복된 96% porous glass에 azo-linkage를 형성시켜 결합하게 한후, 2.5% glutaraldehyde로 처리하여 효소를 고정화시켰다. 효소기질로는 용해도가 높고 점도가 낮은 30% enzyme thinned cornstarch (dextrose equivalent 값 : 24)를 사용하여 plug flow-column reactor에서 연속반응시켰다. 반응 최적 pH는 수용성효소의 5.0보다 alkaline 쪽으로 기울어져 7.0으로 나타났고, 고정화반응에 따라 열안정성이 높아지고 $40{\sim}60^{\circ}C$에서 최적 온도범위를 가리키며, Km값은 수용성 효소의 1.25mM보다 낮은 1.04mM값을 보여 주었다. 따라서, pH 7.0, $45^{\circ}C$에서 160시간 동안 corn starch를 기질로 효소반응을 시켜 glucose 90.3%, maltose 8.0%인 DE값 94.0인 전분당분해산물을 획득할 수 있었다.

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한국산 대추의 Endo-Polygalacturonase의 특성 (Characteristics of Endo-Polygalacturonase from Korean jujube)

  • 최청;천성숙;조영제;안봉전;김영활;이선호;김성
    • Applied Biological Chemistry
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    • 제37권5호
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    • pp.356-360
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    • 1994
  • 한국산 대추의 endo-polygalacturonase는 최대 효소활성을 위한 pH는 5.0, 최적온도는 $50^{\circ}C$였으며 pH안정범위는 $4.0{\sim}5.0$, 열안정성은 $70^{\circ}C$에서 1시간 열처리 하였을 때 약 35% 실활되었다. 금속이온중 $Cu^{++}$, $Mn^{++}$이온이 효소의 활성을 촉진시켰으며, $Na^+$, $Ba^{++}$, $Mg^{++}$, $Fe^{++}$ 등의 이온에 의해서는 활성이 저해되었다. 효소저해제 중 maleic anhydride, iodine, 2,4-dinitrophenol을 처리하였을 때 활성저해가 관찰되어 효소의 histidine 잔기의 imidazol기가 활성부위로 판단되었다.

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Hydrocolloid가 빵 반죽의 레올로지 특성에 미치는 영향 (Effect of Hydrocolloids on Rheological Properties of Bread Dough)

  • 조현;이명구;이정훈;이시경
    • Applied Biological Chemistry
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    • 제51권1호
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    • pp.6-10
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    • 2008
  • Hydrocolloid 로 arabic gum, carboxyl methyl cellulose, pectin을 각각 강력분에 0.2%와 0.5% 첨가하여 반죽의 레올로지 특성 변화를 farinograph, 반죽의 pH, extensograph, fermometer, amylograph 등으로 분석하였다. Hydrocolloid 첨가 시 farinograph에서 흡수율은 증가되었고 CMC 0.5% 첨가시 70.8%로 흡수율이 가장 높았다. 반죽발전시간은 길어졌으나 안정도는 낮아졌다. Hydrocolloid 첨가로 반죽의 pH는 저하되었고 pectin 0.5% 첨가시 가장 낮았다. Extensograph에서 반죽의 저항성은 감소하였고 신장성은 증가하였으며 R/E 값은 낮아졌다. 반죽의 가스발생량은 증가하여 CMC를 0.2% 첨가시 가장 많은 가스를 발생하였다. Amylograph에서 초기호화온도는 $0.5-1.5^{\circ}C$ 싱승하였으나 최고점도온도는 $1-1.5^{\circ}C$ 낮아졌고 최고점도는 높아졌다.

Meat Quality Traits of Longissimus Muscle of Hanwoo Steers as a Function of Interaction between Slaughter Endpoint and Chiller Ageing

  • Dashdorj, Dashmaa;Oliveros, Maria Cynthia R.;Hwang, In-Ho
    • 한국축산식품학회지
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    • 제32권4호
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    • pp.414-427
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    • 2012
  • Carcass characteristics and meat quality traits as a function of endpoint months of slaughter age (26 vs 32 mon) and chiller ageing (1 vs 10 d) were evaluated for m. longissmus of 26 Hanwoo steers fed with commercial diets including whole crop barley silage. Totally twenty six Hanwoo steers for 6 mon of age that were fed until 26 mon of age constituted the short term-fed group and fed until 32 mon of age constituted long-term fed group. Carcasses were chilled for 24 h and were graded. Strip loin samples were divided into two age groups (1 d and 10 d). Long-term feeding increased carcass weight, rib-eye area, yield grade, marbling score, firmness and quality grade of the meat. The feeding for 32 mon produced tender, juicy meat (p<0.01) with lower cooking loss and higher rating score (p<0.05) than short term feeding, while other quality traits were not influenced by the length of feeding. Intramuscular fat content and oxidative stability (TBARS value) were significantly (p<0.05) higher in beef from long-term feeding however the length of feeding did not alter the fatty acid composition. Chiller aging reduced instrumental tenderness (WBSF value), improved color, sensory tenderness, acceptability and rating of beef. The results of the present study mirrors that Hanwoo steers until 32 mon of age overall improved carcass traits and palatability compared to that for 26 mon. However, from the viewpoints of economical and environmental aspects, cost of the additional feeding for 6 mon for value-adding of eating quality was relatively high and the effects in turn were limited.

Rice bran fermentation by lactic acid bacteria to enhance antioxidant activities and increase the ferulic acid, ρ-coumaric acid, and γ-oryzanol content

  • Le, Bao;Anh, Pham Thi Ngoc;Kim, Jung-Eun;Cheng, Jinhua;Yang, Seung Hwan
    • Journal of Applied Biological Chemistry
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    • 제62권3호
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    • pp.257-264
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    • 2019
  • Rice bran is considered a natural source of antioxidants. In this study, rice bran was fermented with lactic acid bacteria to increase its antioxidant activity. Four strains isolated from fermented food, Lactobacillus plantarum MJM60383, Lactococcus lactis subsp. lactis MJM60392, Lactobacillus fermentum MJM60393, and Lactobacillus paracasei MJM60396, were confirmed as safe through stability tests such as safety assessment for biogenic amine production, hemolytic activity, and mucin degradation, and showed high reducing capacity. The antioxidant activity of rice bran fermentation altered by these strains was evaluated using several methods including measurement of $Fe^{2+}$ chelating activity and scavenging activity by 1,1-diphenyl-2-picryl-hydrazil (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and nitric oxide assays. In this study, the total phenolic content and ${\gamma}$-oryzanol were evaluated by high-performance liquid chromatography. Compared to non-fermented rice bran and a commercial product, rice bran fermented with Lactococcus lactis subsp. lactis MJM60392 showed the highest phenolic content (844.13 mg GAE/g). Moreover, the content of ferulic acids, ${\rho}$-coumaric acid, and ${\gamma}$-oryzanol in rice bran increased after fermentation with L. lactis subsp. lactis MJM60392 and L. fermentum MJM60393 compared to other samples. Indeed, the DPPH radical scavenging activity and NO scavenging activity were also found to be high in these fermented rice brans. These results indicated that fermentation with lactic acid bacteria increases the active compound levels and the potent antioxidant activities of rice bran.

고단백질 함유 대두와 완두 중 Propineb 잔류분석을 위한 제단백 효과 (Improvement of Analytical Method for Propineb Residues in Glycine max (L.) Merrill and Pisum sativum L. using Deproteinization Process)

  • 함헌주;최정윤;허장현
    • 한국환경농학회지
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    • 제41권3호
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    • pp.206-216
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    • 2022
  • BACKGROUND: Dithiocarbamate fungicide propineb can be analyzed quantitatively by derivatization reaction followed by HPLC/UVD, which has high reproducibility and stability. However, the presence of high protein in soybeans and peas affects the derivatization process resulting in extremely low recoveries. Therefore, this study was conducted to improve the analytical method for analysis of propineb in soybeans and peas by applying a deproteinization process using chloroform-gel method. METHODS AND RESULTS: The deproteinization process was carried out up to 6 times for soybeans and 5 times for peas using 50 mL chloroform. After 4 times of deproteinization process followed by a derivatization reaction with methyl iodide, the recovery yields of propineb in both pulses were >90%. However, the recovery yield tended to decrease when the deproteinization process was performed more than 5 times. The method limit of quantification (LOQ) was 0.04 mg/L. The recovery conducted in triplicate at 10 times and 50 times of the LOQ ranged from 87.2 to 95.0 % with a coefficient of variation <10%. CONCLUSION(S): This study confirmed that 4 times of deproteinization process using the chloroform-gel method was effective when derivatizing and analyzing dithiocarbamate fungicides in pulses with high protein content. However, depending on the initial protein content present in the pulses, there was a difference in the recovery: the lower the protein content, the higher the recovery rate of propineb. It is expected that the method proposed in this study could be applied to remove high content of protein as analytical interference substance from agricultural samples.

하이드록시아파타이트/포스터라이트 복합분말의 분사코팅에 의한 3Y-TZP 기판의 표면개질과 생체활성 증진 (Surface Modification and Bioactivity Improvement of 3Y-TZP Substrate by Spray Coating of Hydroxyapatite/Fosterite Composite Powder)

  • 윤유현;이종국
    • 한국재료학회지
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    • 제33권8호
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    • pp.337-343
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    • 2023
  • 3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals) ceramics have excellent mechanical properties including high fracture toughness, good abrasion resistance as well as chemical and biological stability. As a result, they are widely used in mechanical and medical components such as bearings, grinding balls, and hip implants. In addition, they provide excellent light transmittance, biocompatibility, and can match tooth color when used as a dental implant. Recently, given the materials' resemblance to human teeth, these ceramics have emerged as an alternative to titanium implants. Since the introduction of CAD/CAM in the manufacture of ceramic implants, they've been increasingly used for prosthetic restoration where aesthetics and strength are required. In this study, to improve the surface roughness of zirconia implants, we modified the 3Y-TZP surface with a biocomposite of hydroxyapatite and forsterite using room temperature spray coating methods, and investigated the mixed effect of the two powders on the evolution of surface microstructure, i.e., coating thickness and roughness, and biological interaction during the in vitro test in SBF solution. We compared improvement in bioactivity by observing dissolution and re-precipitation on the specimen surface. From the results of in vitro testing in SBF solution, we confirmed improvement in the bioactivity of the 3Y-TZP substrate after surface modification with a biocomposite of hydroxyapatite and forsterite. Surface dissolution of the coating layer and the precipitation of new hydroxyapatite particles was observed on the modified surface, indicating the improvement in bioactivity of the zirconia substrate.