• 제목/요약/키워드: Protein Denaturation

검색결과 166건 처리시간 0.039초

Photocatalytic Degradation of E. coli and S. aureus by Multi Walled Carbon Nanotubes

  • Sharon, Madhuri;Datta, Suprama;Shah, Sejal;Sharon, Mahesh War;Soga, T.;Afre, Rakesh
    • Carbon letters
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    • 제8권3호
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    • pp.184-190
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    • 2007
  • Carbon Nano Tubes could be either metallic or semi-conducting in nature, depending on their diameter. Its photocatalytic behavior has given an impetus to use it as an anti-microbial agent. More than 95% Escherichia coli and Staphylococcus aureus bacteria got killed when exposed to Carbon Nano Tubes for 30 minutes in presence of sunlight. Carbon Nano Tubes are supposed to have smooth surface on to which it accumulates positive charges when exposed to light. The surface that is non illuminated has negative charge. At the cellular level microorganisms produce negative charges on the cell membrane, Therefore damaging effect of multi walled carbon nano tubes (exposed to light) on the microorganisms is possible. In this paper, photo catalytic killing of microbes by multi walled carbon nano tubes is reported. Killing was due to damage in the cell membrane, as seen in SEM micrographs. Moreover biochemical analysis of membrane as well as total cellular proteins by SDS PAGE showed that there was denaturation of membrane proteins as well as total proteins of both the microbes studied. The killed microbes that showed a decrease in number of protein bands (i.e. due to breaking down of proteins) also showed an increase in level of free amino acids in microbes. This further confirmed that proteins got denatured or broken down into shorter units of amino acids. Increased level of free amino acids was recorded in both the microbes treated with multi walled carbon nano tubes and sunlight.

A Simple Detection of Sweetpotato Feathery Mottle Virus by Reverse Transcription Polymerase Chain Reaction

  • Jeong Jae-Hun;Chakrabarty Debasis;Kim Young-Seon;Eun Jong-Seon;Choi Yong-Eui;Paek Kee-Yoeup
    • Journal of Plant Biotechnology
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    • 제5권2호
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    • pp.83-86
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    • 2003
  • A reverse transcription polymerase chain reaction (RT-PCR) protocol was developed using two specific 22-mer primers located in coat protein gene of SPFMV. A 411 bp PCR-product was detected in virus infected plants as well as tissue culture raised sweet potato but not in healthy plants. For optimization of RT-PCR protocol, the optimum crude nucleic acid concentration, annealing temperature, primer concentration and numbers of PCR-cycle for maximum sensitivity and specificity were determined. The optimum condition for RT-PCR was as follows: RT-PCR reaction mixture was one-step mixture, containing 50 pmol of primer, 30 units of reverse transcriptase, 5 units of RNasin, and the crude nucleic acid extracts (200 ng). In RT-PCR, cDNA was synthesized at $42^{\circ}C$ for 45 min before a quick incubation on ice after pre-denaturation at $95^{\circ}C$ for 5 min. The PCR reaction was carried out for 40 cycles at $96^{\circ}C$ for 30 see, $63^{\circ}C$ for 30 sec, $72^{\circ}C$ for 1 min, and finally at $72^{\circ}C$ for 10 min. The viral origin of the amplified product was confirmed by sequencing, with the sequence obtained having $95-98\%$ homology with published sequence data for SPFMV. The benefits of this RT-PCR based detection of SPFMV would be simple, rapid and specific.

The influence of ultrasound and adenosine 5'-monophosphate marination on tenderness and structure of myofibrillar proteins of beef

  • Zou, Ye;Yang, Heng;Zhang, Muhan;Zhang, Xinxiao;Xu, Weimin;Wang, Daoying
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권10호
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    • pp.1611-1620
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    • 2019
  • Objective: The aim was to investigate the influence of ultrasound and adenosine 5'-monophosphate (AMP) marination (UAMP) on tenderness and structure of myofibrillar proteins of beef. Methods: Five groups, the untreated meat (Control), deionized water marination (DW), ultrasound followed by DW (UDW), AMP marination (AMP), and ultrasound followed by AMP (UAMP) were studied. Myofibrillar fragmentation, cooking loss, shear force, thermograms, histological observation of meats and myofibrillar proteins properties were investigated in these different treatments. Results: The results showed that UAMP significantly increased myofibrillar fragmentation index from 152 (Control), 231 (AMP), and 307 (UDW) to 355 (p<0.05), respectively. The lowest cooking loss, shear force and peak denaturation temperature were observed in UAMP. In histological observation, UDW and UAMP had more fragmented muscular bundles than the others. Furthermore, a drastic increase in ${\alpha}$-helix and decrease in ${\beta}$-sheet of myofibrillar proteins was observed in UAMP, implying the disaggregation of protein samples. The synchronous fluorescence spectra of myofibrillar proteins in UAMP suggested the combination of ultrasound and AMP could accelerate the unfolding molecular structure and destroying hydrophobic interactions. The results of circular dichroism and synchronous fluorescence spectra for myofibrillar proteins coincided with the microstructures of beef. Conclusion: The results indicate that ultrasound combined with AMP improved meat tenderness not only by disruption in muscle integrity, increasing water retention, but also altering their spatial structure of myofibrillar proteins.

Effect of dietary pumpkin (Cucurbita moschata) seed meal on layer performance and egg quality characteristics

  • Vlaicu, Petru Alexandru;Panaite, Tatiana Dumitra
    • Animal Bioscience
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    • 제35권2호
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    • pp.236-246
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    • 2022
  • Objective: The objective of this study was to investigate the effect of dietary pumpkin (Cucurbita moschata) seed meal (PSM) on laying hens' performance, quality, fatty acids, cholesterol, antioxidant compounds and shelf life of eggs. Methods: Eighty Tetra SL laying hens, 50-week-old, were randomly divided into two equal groups, having 10 replicates with 4 birds in each. The control (CON) treatment was fed with basal diet, while experimental treatment was fed a diet with 9% PSM, for a 6 week period. Results: Dietary PSM significantly decreased average daily feed intake (p<0.05), with no significant effect on other performance parameters. The PSM, enriched the eggs with polyunsaturated fatty acids, especially α linolenic acid (0.33 vs 0.21 g/100 g) and linoleic acid (20.65 vs 18.37 g/100 g), whereas it reduced the amount of arachidonic acid with 3.91% and n-6/n-3 ratio in PSM eggs compared with CON. The inclusion of 9% PSM significantly (p<0.05) diminished the cholesterol concentration in yolk with 11.31% and in egg with 10.38%, in respect to the CON samples. The significantly (p<0.05) higher concentration of polyphenols and antioxidant compounds, determined in PSM eggs, proved to be effective on shelf life of eggs preserved at refrigerator (5℃) and room temperature (21℃) for 28 days, by delaying the lipid oxidation and protein denaturation. This effect was reflected in significantly (p<0.05) higher Haugh unit in eggs stored 28 days at 21℃ and lower albumen pH values for the overall storage time, both at 5℃ and 21℃, proving the antioxidant effect of pumpkin. Conclusion: Dietary PSM supplementation was significantly effective on average daily feed intake and egg quality by increasing some fatty acids while lowering the cholesterol concentration. Also, PSM proved to be effective improving shelf life of eggs for 28 days storage time.

Effect of sea tangle extract on the quality characteristics of reduced-salt, low-fat sausages using pre-rigor muscle during refrigerated storage

  • Geon Ho Kim;Koo Bok Chin
    • Animal Bioscience
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    • 제36권11호
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    • pp.1738-1746
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    • 2023
  • Objective: The aim of this study was to investigate quality characteristics of reduced-salt, low-fat pork sausage (PS) using pre-rigor muscle and sea tangle extract (STE) to reduce salt level of sausages during refrigerated storage. Methods: Pork ham was prepared with pre-rigor and post-rigor muscle from the local market. Sausages using post-rigor muscle were manufactured with the 1.5% of salt content, and samples with pre-rigor muscle were processed by different salt concentrations (0.8%). Accordingly, PSs were prepared in 4 treatments (REF, PS with 1.5% of salt using post-rigor muscle; CTL, PS with 0.8% of salt using pre-rigor muscle; TRT1, PS with 0.8% of salt and 5% of STE using pre-rigor muscle; TRT2, PS with 0.8% of salt and 10% of STE using pre-rigor muscle). For the evaluation of quality characteristics and shelf-life of reduced-salt PS, pH and color values, cooking loss (%), expressible moisture (%), textural properties, lipid oxidation (thiobarbituric reactive substances), protein denaturation (volatile basic nitrogen), and microbiological analysis (total plate counts and Enterobacteriaceae counts) were determined. Results: The pH and temperature of pre-rigor raw pork ham were higher than those of post-rigor pork ham. Hardness of TRT2 was higher than that of REF or CTL. TRT2 had higher gumminess and chewiness than CTL. TRT1 and TRT2 had lower volatile basic nitrogen than CTL. Total plate counts of TRT2 were lower than those of CTL. Expressible moisture values of TRT1 and TRT2 were similar to those of REF. The addition of STE into PS improved functional properties and shelf-life of PS. Conclusion: Reduced-salt PS containing pre-rigor muscle and STE had similar functional properties to those of regular-salt ones, while containing approximately 47% less salt compared to regular-salt level.

보리새우육의 부분동결저장중 단백질 및 아미노산의 조성변화 (Postmortem Changes of the Protein and Amino Acid Composition of Muscles in the Partially Frozen Prawn, Pandalus japonica)

  • 변재형;최영준;김정한;조권옥
    • 한국수산과학회지
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    • 제17권4호
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    • pp.280-290
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    • 1984
  • 부분동결상태하의 선도 변화와 육단백질 조성변화와의 관계를 규명하기 위하여, 보리새우를 시료로하여 부분동결 조건($-3^{\circ}C$)에 저장하여 두고 저장일수의 경과와 더불어 선도 변화의 단계별로 육의 단백질의 조성, 단백질 구성아미노산 및 유리아미노산의 조성 등의 변화를 비교, 분석하였다. 그리고, 단백질의 조성 변화는 이를 엄밀히 검토하기 위하여, 육에서 근형질 단백질과 근원섬유 단백질을 각각 추출하고 선도변화에 따른 각 단백질의 구성 subunit의 변화를 SDS-PAG 전기영동분석에 의하여 검토하였으며, 한편, 근원섬유 단백질에 대하여는 $-3^{\circ}C$$-20^{\circ}C$에 저장하면서 Ca-ATPase 활성도의 변화를 측정하여 변성의 속도정수($K_D$)도 구하였다. 보리새우의 육중에는 약$23\%$ 조단백질을 함유하고 있었으며, 단백질조성을 분석한 결과, 근형질단백질 $31.45\%$, 근원섬유 단백질 $5.04\%$, 세포내잔사단백질 $10.30\%$, 그리고 기질 단백질 $2.17\%$로 이루어져 있었다. 부분동결 저장 중의 선도변화를 선도변화 지표인 K-값, 총휘발성 염기질소량 및 pH의 변화로서 측정한 결과, 저장 26일째에 부패 초기에 접근하는 총휘발성 염기질소량 $25.29mg\%$, K-값 $31.36\%$, pH 8.83에 도달하였다. 부분동결 저장 중에는 저장기간의 경과와 더불어 근원섬유 단백질은 현저한 감소를 보였으며 기질단백질은 조금씩 감소하였다. 그러나 세포내잔사 단백질은 많은 증가를 보였고 근형질 단백질도 조금 증가하였다. 별도로 근원섬유 단백질의 일부를 $-3^{\circ}C$$-20^{\circ}C$에 두고 Ca-ATPase 활성도의 변화를 측정하여 변성속도정수를 구하였더니 $-3^{\circ}C$에서는 $K_D=9.03{\times}10^{-6}sec^{-1}$, 그리고 $-20^{\circ}C$에서는 $K_D=4.42{\times}10^{-6}sec^{-1}$을 보여 $-20^{\circ}C$ 일때가 훨씬 안정하였다. 근형질 단백질과 근원섬유 단백질의 구성 subunit의 변화를 SDS-PAG 전기영동법으로 분석한 결과, 근형질 단백질은 즉살했을때 12개의 subunit 이던것이 부패초기에 가까운 상태를 보인 26일째에는 8개 subunit만이 남았고, 근원섬유 단백질에 있어서는 즉살했을 때 17개 subunit이던 것이 26일이 경과했을 때는 22개 subunit로 증가하였다. 근원섬유 단백질 구성 subunit중에서 저장중에 새로히 출현한 subunit는 30,000, 41,000, 107,000, 136,000, 170,000, 173,000, 185,000 및 198,000 dalton의 각 subunit이었으며, 소멸한 subunit는 19,000, 22,000, 140,000 및 165,000 dalton의 각 subunit였다. 부분동결 저장 중 단백질을 구성하는 아미노산의 조성 변화를 분석한 결과, 대부분의 아미노산은 시일의 경과와 더블어 일률적으로 조금씩 감소하는 경향이었다. 그러나 유리아미노산의 조성 변화에 있어서는 즉살한 보리새우육 중에는 glycine, proline, arginine, alanine 및 taurine 등 5종의 아미노산이 총유리아미노산의 $93\%$를 차지하였다. 저장중에는 taurine, valine, leucine, phenylalanine, serine, Lysine, methionine, isoleucine, histidine 등이 2배 이상 증가하였으나 proline만은 대폭 감소한 것이 특징이었다.

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다탐색(多探索)법을 통한 저자극성 액체 세정제 조성물 개발 (A Low Irritant Liquid Cleanser Composition Developed by Multi-Screening Methods)

  • 김배환;현기안;정지윤;윤삼숙;강한철;박선희;고강일;김기호
    • 대한화장품학회지
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    • 제31권1호
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    • pp.51-58
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    • 2005
  • 세정제에 널리 상용화되어 있는 알킬에톡시설페이트 계의 음이온 계면활성제는 피부 흡착의 특성 때문에 충분히 헹구어 내지 않으면 피부에 잔존되어 자극의 원인이 되어 염증 반응을 일으키게 된다. 따라서 기존의 음이온 계면활성제를 대체 또는 보완하기 위해 기존의 계면활성제들을 단백질 변성 실험, 세포 독성 그리고 IL-1$\alpha$ 측정을 통해 선별하였다. 본 연구는 저자극성의 음이온 또는 비이온, 양쪽성 이온의 14종의 계면활성제와 민감성 피부를 위해 제조된 13종의 기존 세정제 제품에 대한 세포독성을 실시하여, 가장 독성이 낮은 계면활성제로 sodium laureth sulfate (음이온), sodium cocoyl isethionate (음이온), sodium lauroamphoacetate (양성이온), cocamidopropyl betaine (양성이온), alkyl polyglycoside (비이온)가 선택되었고 2종의 기존 세정제 제품을 비교 제형으로 선택하였다. 5종의 계면활성제를 20종의 formulation으로 제조하여 단백질 변성( <3M SLS ($13.2\%$)), 세포독성 실험 및 폐첩포 실험을 통하여 다시 5종을 선별하였다. 이들 제형을 진피 배양으로 세포독성 및 IL-1$\alpha$ 방춘량을 조사하여 가장 자극이 낮은 계면활성제 제형을 선택하였으며, 첨가된 계면활성제의 자극을 완화하기 위하여 항염과 보습 효과가 우수한 마치현 추출물($3\%,\;5\%$)과 fructan ($3\%,\;5\%$)을 농도별로 첨가한 제형을 제조하여 가장 안전성이 뛰어난 농도를 선택하였다. 최종적으로 선택된 제형 5번을 3차원 세포 배양을 통한 인공피부를 이용하여 가장 자극이 낮게 나타난 기존의 제품들과 세포 독성 및 IL-1$\alpha$ 방출량을 비교 조사하여 저자극성의 액체 세정제를 개발하였다.

폐계가슴살 회수단백질을 활용한 돈육소시지의 품질 특성에 영향하는 동충하초, 누에고치 및 Conjugated Linoleic Acid (CLA) 첨가 효과 (Effect of Cordyceps ochraceostromat, Silkworm Cocoon, and Conjugated Linoleic Acid (CLA) on the Quality Characteristics of Pork Sausage Manufactured with Protein Recovered from Breast of Spent Laying Hen)

  • 진상근;김일석;강석남;최승연;허인철;이중근;양한술
    • Journal of Animal Science and Technology
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    • 제52권2호
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    • pp.131-140
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    • 2010
  • 기능성 물질의 첨가가 노폐계육단백질을 활용한 돈육 소시지의 저장 중 품질 및 저장성에 미치는 영향에 대해 알아보고자, 햄육만을 사용한 대조구에 40% 기계발골육 회수단백질을 활용한 T1, 40% 회수단백질에 0.1% 동충하초 분말을 첨가한 T2, 0.1% 누에고치 분말을 첨가한 T3, 0.1% CLA를 첨가한 T4 및 0.05%씩 동충하초, 누에고치 및 CLA를 각각 첨가하여 T5, T6 및 T7으로 분류하여 4주간 저장하였다. 저장 말기 T4를 제외하곤 수분 함량은 차이가 없었으며, 단백질 함량 결과, 처리구에서 높은 경향을 보이며, 지방 함량 또한40% 회수단백질 대체시 높게 나타났다. 이러한 경향은 40% 회수단백질을 대체하여도 제품내 수분 함량의 변화가 없으며, 물리적 특성인 보수력과 가열감량 또한 대조구와 처리구간에 차이를 나타내지 않아 소시지 제품 내 수분결합력 및 수분손실률인 loss 값의 차이가 없는 것을 확인하였다. 또한 기능성 물질첨가에 따른 차이보다는 40% 회수단백질 대체는 높은 명도 및 pH 값을, 경도, 응집성 및 씹힘성을 떨어뜨려 연한 조직감을 형성하였다. 저장성 실험 결과, 총균수는 대조구에서 오히려 낮게 나타났으며, 지방산패도 값은 40% 회수단백질의 대체에 따른 차이보다는 저장 4주차의 T4, T5 및 T6에서 낮게 나타나 동충하초 및 누에고치 0.1% 첨가보단 0.1% CLA 및 동충하초, 누에고치 및 CLA 혼합 첨가구에서 지방산패도를 억제시키는 것으로 나타났다. 40% 회수 단백질 및 기능성 물질 또한 VBN 값에 영향하였다. 이러한 결과들은 관능평가 결과, 기존의 축육 소시지와 비교하여 40% 회수단백질 및 기능성 물질을 첨가한 제품과의 기호도 차이를 보이지 않아 노폐계육의 산업적 활용도뿐만 아니라 동충하초, 누에고치 및 CLA첨가를 통한 기능성 제품 생산이 가능할 것으로 판단된다.

산화 스트레스에 의존한 식물 및 진핵세포 2-시스테인 퍼록시레독신의 기능 조절 (Oxidative Stress-dependent Structural and Functional Regulation of 2-cysteine Peroxiredoxins In Eukaryotes Including Plant Cells)

  • 장호희;김선영;이상열
    • Journal of Plant Biotechnology
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    • 제33권1호
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    • pp.1-9
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    • 2006
  • 도처에 분포하는 peroxiredoxins (Prxs)은 세포 내 방어신호전달 과정에서 다양한 기능을 하는 것으로 나타났다. Prxs는 크게 typical 2-Cys Prx, atypical 2-Cys Prx와 1-Cys Prx의 세 부류로 분류되는데, 이것들은 cysteine 잔기의 수와 촉매기전에 따라 구분된다. 세 종류의 단백질 중, N-말단에 peroxidatic cysteine 잔기를 포함하는 typical 2-Cys Prx는 $H_2O_2$ 분해과정 동안 과산화물-의존적인 sulfenic acid로의 산화와 thiol-의존적 환원과정이 순환되어 일어난다. Sulfenic acid는 고농도의 $H_2O_2$와 Trx, Trx reductase와 NADPH를 포함하는 촉매 요소의 존재하에 cysteine sulfenic acid로 과산화 될 수 있다 과산화된 2-Cys Prx는 ATP 의존성 효소인 sulfiredoxin의 작용에 의해 천천히 환원된다. 세포가 강력한 산화나 열 충격 스트레스에 노출되면, 2-Cys Prx는 LMW 단백질에서 HMW complex로 구조를 변화시켜 peroxidase에서 chaperone으로 기능의 전환을 일으킨다. 2-Cys Prx의 C-말단 부분 역시 이러한 구조적 전환에 중요한 역할을 한다. 따라서, C-말단이 잘려진 단백질은 과산화가 되지 않고 단백질의 구조와 기능이 조절될 수 없다. 이러한 반응들은 활성 자리인 peroxidatic cysteine 잔기에 의해 일차적으로 유도되며, 그것은 세포에서 '$H_2O_2$ sensor' 로서 작용하다. 2-Cys Prx의 가역적인 구조와 기능 변화는 세포가 외부자극에 적응하는 수단으로 작용하며, 아마도 세포내 방어신호체계를 활성화 시키는 것으로 생각된다. 특히, chloroplast에 존재하는 식물 2-Cys Prx는 촉매반응 동안 주된 구조적인 변화를 나타내는 역동적인 단백질 구조를 가지고 있어서, 산화-환원 의존적으로 super-complex를 형성하고 가역적으로 thylakoid membrane에 부착한다.

호화점 이하에서 옴가열이 감자 전분의 열적특성에 미치는 영향 (Effect of Ohmic Heating at Subgelatinization Temperatures on Thermal-property of Potato Starch)

  • 차윤환
    • 한국식품영양학회지
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    • 제25권4호
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    • pp.1068-1074
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    • 2012
  • Ohmic heating uses electric resistance heat which occurs equally and rapidly inside of food when electrical current is flown into. In other study, we researched about soybean protein's characteristic changes by ohmic heating. Nevertheless treated same temperature, denaturation of soybean protein were accelerated by ohmic heating than conventional heating. In this time, we studied thermal property change of potato starch by ohmic heating besides conventional heating. For this purpose, potato starch was heated at same subgelatinization temperature by ohmic and conventional heating. And thermal properties were tested using DSC. Annealing of starch is heat treatment method that heated at 3~4% below the gelatinization point. DSC analysis results of this study, the $T_o$, $T_p$, $T_c$ of potato starch levels were increased, whereas $T_c{\sim}T_o$ was narrowed. This thermal property changes appear similar to annealing's result. It is thought the results shown in this study, because the heating from below the gelatinization point. 6, 12, 24, 72, and 120 hours heating at $55^{\circ}C$ for potato starch, $T_o$, $T_p$, $T_c$ values continue to increased with heating time increase. The gelatinization temperature of raw potato starch was $65.9^{\circ}C$ and the treated starch by conventional heating at $55^{\circ}C$ for 120 hr was $72^{\circ}C$, ohmic was $76^{\circ}C$. The gelatinization range of conventional (72 hr) was $10^{\circ}C$, ohmic was $8^{\circ}C$. In case of 24 hours heating at 45, 50, 55, 60, $65^{\circ}C$ for potato starch, the result was similar to before. $T_o$, $T_p$, $T_c$ values continue to increased and gelatinization range narrowed with heating temperature increase. In case of conventional heating at $60^{\circ}C$, the results of gelatinization temperature and range were $70.1^{\circ}C$ and $9.1^{\circ}C$. And ohmic were $74.4^{\circ}C$ and $7.5^{\circ}C$. When viewed through the results of the above, the internal structure of starch heated by ohmic heating was found that the shift to a more stable form and to increase the homology of the starch internal structure.