• The Plant Pathology Journal
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• 제31권3호
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• pp.278-289
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• 2015

Indigenous strains of Trichoderma species isolated from rhizosphere soils of Tea gardens of Assam, north eastern state of India were assessed for in vitro antagonism against two important tea fungal pathogens namely Pestalotia theae and Fusarium solani. A potent antagonist against both tea pathogenic fungi, designated as SDRLIN1, was selected and identified as Trichoderma viride. The strain also showed substantial antifungal activity against five standard phytopathogenic fungi. Culture filtrate collected from stationary growth phase of the antagonist demonstrated a significantly higher degree of inhibitory activity against all the test fungi, demonstrating the presence of an optimal blend of extracellular antifungal metabolites. Moreover, quantitative enzyme assay of exponential and stationary culture filtrates revealed that the activity of cellulase, ${\beta}$-1,3-glucanase, pectinase, and amylase was highest in the exponential phase, whereas the activity of proteases and chitinase was noted highest in the stationary phase. Morphological changes such as hyphal swelling and distortion were also observed in the fungal pathogen grown on potato dextrose agar containing stationary phase culture filtrate. Moreover, the antifungal activity of the filtrate was significantly reduced but not entirely after heat or proteinase K treatment, demonstrating substantial role of certain unknown thermostable antifungal compound(s) in the inhibitory activity.

• Journal of Microbiology and Biotechnology
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• 제17권6호
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• pp.897-904
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• 2007

The aim of this paper is to discuss the methodology of our investigation of the dynamics of protein degradation and the total in situ protealytic activity in meso/eutrophic, eutrophic, and hypereutrophic freshwater environments. Analysis of the kinetics and rates of enzymatic release of amino acids in water samples preserved with sodium azide allows determination of the concentrations of labile proteins $(C_{LAB})$, and their half-life time $(T_{1/2})$. Moreover, it gives more realistic information on resultant activity in situ $(V_{T1/2})$ of ecto- and extracellular proteases that are responsible for the biological degradation of these compounds. Although the results provided by the proposed method are general y well correlated with those obtained by classical procedures, they better characterize the dynamics of protein degradation processes, especially in eutrophic or hypereutrophic lakes. In these environments, processes of protein decomposition occur mainly on the particles and depend primarily on a metabolic activity of seston-attached bacteria. The method was tested in three lakes. The different degree of eutrophication of these lakes was clearly demonstrated by the measured real proteolytic pattern and confirmed by conventional trophic state determinants.

• Applied Biological Chemistry
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• 제33권4호
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• pp.325-329
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• 1990

젓갈에서 분리한 B. subtilis p-4와 B. licheniformis p-5 프로테아제의 기질(카제인)에 대한 친화도를 측정한 결과 각각 0.38mM, 0.18mM이었고 열변성에 의한 특성을 반응속도론적으로 검토한 결과, p-4 프로테아제는 $50^{\circ}C$에서 80분 열처리할 때 20%의 잔존 활성을 보였고, p-5 프로테아제는 거의 실활되었는데 일차반응식을 따랐다. 그리고 p4, p-5 프로테아제의 변성 속도 상수는 각각 $40^{\circ}C$에서 $12.2{\times}10^{-5}/sec,\;19.0{\times}10^{-5}/sec,\;50^{\circ}C$에서는 $35.7{\times}10^{-5}/sec,\;46.3{\times}10^{-5}/sec$였다. 또 활성화 에너지는 p-4프로테아제가 19.6Kca1/mole, p-5 프로테아제는 15.2Kcal/mole로 p-5 프로테아제가 열변성에 민감한 것을 알 수 있었다. 활성화 자유에너지는 p-4, p-5 프로테아제 모두 온도가 상승함에 따라 약간 증가하였는데 $40^{\circ}C$에서 각각 23.21, 22.93Kcal/mole, $50^{\circ}C$에서는 23.28, 23.11Kcal/mole이었다. 아미노산 조성은 p-4 프로테아제의 경우 151개의 아미노산 잔기를 가졌으며, 이중 glycine, glutamic acid, proline이 많았고, p-5 프로테아제는 247개의 잔기에 glycine, glutamic acid, aspartic acid가 많았다.

• Journal of Microbiology
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• 제44권5호
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• pp.537-547
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• 2006

This study was designed to determine whether or not Vibrio vulnificus metalloprotease VvpE can promote iron uptake via the proteolytic cleavage of human hemoglobin. We found that V. vulnificus utilized hemoglobin as an iron source more efficiently via the vulnibactin-mediated iron-uptake system than via the HupA-mediated iron-uptake system and, of the proteases produced by V. vulnificus, VvpE was found to be the only protease capable of destroying hemoglobin. However, VvpE expression, on both the transcriptional and protein levels, was suppressed in iron-limited media. However, vvpE transcription, but not extracellular VvpE production, was reactivated by the addition of hemoglobin or inorganic iron into iron-limited media. Moreover, vvpE transcription began only in the late growth phase when V. vulnificus had already consumed most of the iron for growth. In addition, neither vvpE mutation nor in trans vvpE complementation affected the ability of V. vulnificus to acquire iron or to grow in iron-limited media or in cirrhotic ascites containing hemoglobin. Hemoglobin added into iron-limited media was not destroyed, but gradually formed an insoluble aggregate during culture; this aggregation of hemoglobin occurred regardless of vvpE mutation or complementation. These results indicate that VvpE is not required for efficient iron uptake from hemoglobin. On the contrary, hemoglobin or iron is required for efficient vvpE transcription. In addition, a discrepancy exists between vvpE transcription and extracellular VvpE production in iron-limited media containing inorganic iron or hemoglobin, which suggests that additional unknown posttranscriptional events may be involved in the extracellular production of VvpE.

• Mycobiology
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• 제30권3호
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• pp.160-165
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• 2002

Aspergillus niger has been used as a host to express many heterologous proteins. It has been known that the presence of an- abundant protease is a limiting factor to express a heterologous protein. The protease deficient mutant of A. niger was obtained using UV-irradiation. A total of $1{\times}10^5$ spores were irradiated with $10{\sim}20%$ survival dose of UV, 600 $J/m^2$ at 280 nm, and the resulting spores were screened on the casein-gelatin plates. Ten putative protease deficient mutants showing the reduced halo area around colonies were further analyzed to differentiate the protease deficient mutant from other mutant types. Among ten putative mutants, seven mutants showed significant growth defect on nutrient rich medium and two mutants appeared to be the secretory mutants, which resulted in the impaired secretion of extracellular proteins including proteases. A mutant $pro^--20$ showed reduced halo zone without any notable changes in growth rate. In addition, the starchdegrading and glucose oxidase activities in the culture filtrate of $pro^--20$ mutant showed the similar range as that of the parental strain, which suggested that the $pro^--20$ mutant ought to be the protease deficient mutant rather than a secretory mutant. The reduced proteolytic activity of the $pro^--20$ was demonstrated using SDS-fibrin zymography gel. The reduced extracellular proteolysis was quantified by casein degradation assay and, comparing with the parental strain, less than 30% residual extracellular protease activity was detected in the culture filtrate of the $pro^--20$ mutant. The bio-activity of an exogenously supplemented hGM-CSF(human Granulocyte-Macrophage Colony Stimulating Factor) in the culture filtrate of $pro^--20$ mutant was detected until eight times more diluted preparations than that of the parental strain.

• 미생물학회지
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• 제45권1호
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• pp.69-73
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• 2009

단백질 분해효소는 아미노산 간에 존재하는 공유결합인 펩티드 결합을 절단하는 효소이며, 세계적으로 가장 많이 판매되는 효소이다. 해양 심층수로부터 분리된 Micrococcus sp. HJ19의 체외분비 단백질 분해효소를 생산하는 최적의 배지조건을 조사하기 위하여 기본배지로 변형 STY 배지(1% tryptone, 0.15% yeast extract, 0.01% NaCl, 여과살균한 바닷물)를 사용하였다. 탄소원으로 포도당보다 갈락토오스를 사용하였을 때 1.3배로 높은 활성을 보여주었으며, 질소원으로는 casamino acid를 사용하였을 때 가장 낮은 활성을 보여준 반면, 맥아추출물을 사용하였을 때 가장 높은 활성을 나타내었다. 생산된 체외단백질 분해효소는 $35^{\circ}C$에서 최적의 활성을 나타내었으며, 최적 pH는 8.5로 판명되었다.

• 미생물학회지
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• 제43권3호
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• pp.222-226
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• 2007

단백질 분해효소는 아미노산간에 존재하는 peptide결합을 절단하는 효소로 산업적으로 많이 사용된다. 이러한 단백질 분해효소의 새로운 공급원을 찾기 위하여 체외 단백질 분해효소를 생산하는 세균을 둥해 심층수로부터 집식배양으로 분리하였다. 이들 중 빠른 성장과 skim milk를 첨가한 배지에서 가장 큰 투명환을 보여준 균주를 HJ19로 명명하였다. 분리균의 형태학적, 생리생화학적 특성과 16S rRNA gene의 염기서열을 조사한 결과 Micrococcus sp.에 속하는 것으로 나타났다. 분리된 Micrococcus sp. HJ19는 $10^{\circ}C$에서는 자라지 못하였으며 $20^{\circ}C$부터 생육과 효소활성을 보여주었다. 최적 생육 온도는 $37^{\circ}C$였으며, 효소 활성은 $30^{\circ}C$에서 약 480 unit/ml의 활성을 보여 주었다.

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.753-758
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• 2000

Human leptin is identified as a 16kDa (146 amino acids) protein secreted from adipocytes which influences body weight homeostasis. In order to produce active leptin, the human obese gene coding for leptin was expressed in Bacillus subtilis WB600 strain which is deficient in six extracellular proteases. The recombinant leptin was produced in a culture supernatant, and in a culture supernatant, it was contained as high as 48% for total proteins. After simple purification steps, which consisted of ammonium sulfate precipitation and anion-exchange column chromatography, 2.3 mg of leptin with a purity greater than 95% was obtained from the 0.51 culture with the recovery yield of 38.3%. The purified leptin showed the correct folding structure with one disulfied bond.

• 한국미생물·생명공학회지
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• 제23권3호
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• pp.322-328
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• 1995

A thermophilic bacteria showing proteolytic activity against defatted soybean was isolated from soil. It was identified as Bacillus amyloliquefaciens based on its morphological and physiological characteristics. The Bacillus amyloliquefaciens NS 15-4 was cultivated at 50$\circ$C by rotary shaking in a medium containing defatted soybean. An extracellular protease from this strain was purified to homogeneity by ammonium sulfate precipitation, ion exchange, and hydrophobic interaction chromatographies. The molecular weight of the enzyme was estimated to be approximately 30,000 by SDS-PAGE and the N-terminal amino acid sequence of the enzyme was turned out to be AQSVPYGISQIKAPA. The optimum temperature and pH for the enzyme reaction were 60$\circ$C and 11, respectively, and its thermostability was increased by the addition of calcium ion. The enzyme was inactivated by phenylmethylsulfonylfluoride, suggesting it be a serine protease. Comparing with other commercial proteases, the enzyme showed relatively high proteolytic activity against defatted soybean, a water-insoluble protein substrate.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.331.2-331.2
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• 2002

Actinomycetes CS0707 has been isolated in soil sample from location in the Jeju province. Korea, and produces thermostable extracellular proteases. Actinomycetes CS0703 showed the highest protease activity at late exponential phase when grown in OSYM medium (oatmeal 2.0%, soybean meal 1 %, dried yeast 1 %, mannitol 1 %) at $48^{\circ}C$. Three forms of protease(Ta-1, TA-2 and Ta-3) were fractionated by Ultrogel AcA 54 column chromatography, and further purified through ammonium sulfate fractionation, ultramembrane filtration, and DEAE-sepharose CL-6B column chromatography. (omitted)