• 산업식품공학
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• 제14권3호
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• pp.243-248
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• 2010

${\beta}$-Glucosidase 효소활성이 높은 균주를 선발하기 위하여 다양한 김치에서 분리된 젖산균의 ${\beta}$-glucosidase 활성을 탐색하였다. 김치에서 분리된 156개의 젖산균 중 134개의 균주만이 cellobiose를 탄소원으로 대사하였으며, 세포내 ${\beta}$-glucosidase 활성이 세포외 활성보다 현저히 높았다. 배추김치에서 분리된 W. cibaria KFRI88010 균주가 3.7${\pm}$0.5 unit/mg protein으로서 가장 높은 세포내 ${\beta}$-glucosidase 효소활성을 나타내었으며, 효소활성은 pH 5, ${37^{\circ}C}$ 반응조건에서 가장 높게 나타났다. $Mn^{2+}$를 비롯한 금속이온은 효소활성을 크게 저해하였다. W. cibaria KFRI88010 균주를 배양할 때 사용한 탄소원 중, fructose는 cellobiose나 glucose와 비교하여 약 2.5배 이상의 높은 세포내 ${\beta}$-glucosidase 효소활성을 나타내었다.

• 한국동물생명공학회지
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• 제36권4호
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• pp.299-306
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• 2021

Vitrification methods are commonly used for mammalian reproduction through the long-term storage of blastocyst produced in vitro. However, the survival and quality of embryos following vitrification are significantly low compared with blastocyst from in vitro production (IVP). This study evaluates that the survival of frozen-thawed bovine embryos was relevant to mitochondrial superoxide derived mitochondrial activity. Here we present supplementation of the cryopreservation medium with Mito-TEMPO (0.1 µM) induced a significant (p < 0.001; non-treated group: 56.8 ± 8.7%, reexpanded at 24 h vs Mito-TEMPO treated group: 77.5 ± 8.9%, re-expanded at 24 h) improvement in survival rate of cryopreserved-thawed bovine blastocyst. To confirm the quality of vitrified blastocyst after thawing, DNA fragmentation of survived embryos was examined by TUNEL assay. As a result, TUNEL positive cells rates of frozen-thawed embryos were lower in the Mito-TEMPO treated group (4.2 ± 1.4%) than the non-treated group (7.1 ± 3.5%). In addition, we investigated the intracellular ROS and mitochondrial specific superoxide production using DCF-DA and Mito-SOX staining in survived bovine embryos following vitrification depending on Mito-TEMPO treatment. As expected, intracellular ROS levels and superoxide production of vitrified blastocysts after cryopreservation were significantly reduced (p < 0.05) according to Mito-TEMPO supplement in freezing medium. Also, mitochondrial activity measured by MitoTracker Orange staining increased in the frozen-thawed embryos with Mito-TEMPO compared with non-treated group. These results indicate that the treatment of Mito-TEMPO during cryopreservation might induce reduction in DNA fragmentation and apoptosis-related ROS production, consequently increasing mitochondrial activation for developmental capacity of frozen-thawed embryos.

• 한국미생물·생명공학회지
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• 제11권1호
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• pp.15-21
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• 1983

전보에서 분리 동정한 Y-33 균주의 $\beta$-galactosise 효소생산조건을 검토하고 효소를 정제하여 정제효소의 성질을 조사한 결과는 다음과 같다. 1. 효소생산을 위한 최적초발 pH는 7.0이었고 최적온도는 $65^{\circ}C$이었다. 2. 효소는 lactose와 galactose에 의하여 유도되어졌으며 세포내효소이었다. 3. 조효소액을 1차 DEAE-cellulose, 2차 DEAE-cellulose column chromatography 및 Sephadex G-150로 gel filtration하여 정제도가 28.3배, 수율이 15.2%의 정제효소를 얻었다. 4. 정제효소는 polyacrylamide gel 전기 영동에 의하여 순도가 검정되었다. 5. 정제효소의 유당가수분해를 위한 최적작용 온도는 $65^{\circ}C$. pH는 6.5이었다.

• 한국물환경학회지
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• 제33권4호
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• pp.387-393
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• 2017

A chemical batch tests were conducted to evaluate if microwave heating enhances phosphorous release from waste activated sludge (WAS) at pH 2.5, 5, 7, 9 and 11. Polyphosphate-accumulating organisms have a unique physiological feature, which releases intracellular polyphosphate granules when they are exposed under high temperature environments. Microwave irradiation was found to encourage large amount of phosphorus release from WAS, depending on pH and temperature conditions. Most of phosphorus was released below $59^{\circ}C$ within 30 min. A marked increase in phosphorus release was observed under alkaline or acidic conditions. However, based on control tests for phosphorus release under different pH conditions without microwave heating, the largest amount of phosphorus released by microwave irradiation was found at pH 7, followed by 5, 9, 11. On the other hand, crystallization was conducted to obtain magnesium ammonium phosphate (MAP) from phosphate released by microwave heating at pH 7. X-ray diffraction analysis confirmed that the recovered crystalline materials were MAP. MAP is an environmentally friendly fertilizer, which slowly releases ammonia and phosphorus in response to the demand of plant root. Thus, the recovered MAP as a phosphate fertilizer is fully expected to play a important role in the reduction of agricultural non-point pollution.

• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.373-382
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• 1994

A bacterial strain No. 40, which produced extracellular endoglucanase, was isolated from the rumen of Korean native goals and identified to be a genus of Actinomyces sp. The optimum conditions for endoglucanase production in PY-CMC medium were initial pH of 7.0 and 4 days of cultivation at $39^{\circ}C$. When localization of endoglucanase activity of Actinomyces sp. was determined, 68% of the enzyme activity was found in the extracellular fraction, 11% of the activity was detected in the periplasmic space and the remaining activity was in the intracellular and cell-bound fractions. The maximal endoglucanase activity was observed at pH 5.0 and it was most s table at pH 5.0. The optimum temperature of this enzyme activity was $55^{\circ}C$, but enzyme activity was gradually lost at temperature above $60^{\circ}C$. The crude enzyme was activated by addition of 10 mM cysteine and 10 mM DTT. But it was inhibited by addition of 10 mM $Cu^{{+}{+}}$ and $Fe^{{+}{+}}$. This crude enzyme could digest carboxymethylcellulose (CMC), and degrade xylan, avicel, pNPG, and pNPC to a less extent.

• 한국미생물·생명공학회지
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• 제15권6호
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• pp.381-387
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• 1987

생체 내에서 $O_2$를 특이적으로 제거시켜 줌으로써 의학적 응용가치가 매우 높은 것으로 알려진 superoxide dismutase(SOD)에 대하여 연구하였다. 먼저 이 효소의 활성을 여러 속의 세균을 대상으로 검토해된 결과 비교적 높은 활성을 나타낸 Bacillus circulans를 본 실험의 공시균주로 선택한 다음 SOD의 최적 생산 조건을 설정하였다. SOD의 생산은 각 세균에 따라서 양적인 차이는 있으나 종 및 속에 관계없이 다양하게 존재하는 것으로 나타났다. 효소의 생산 조건은 탄소원으로서 1% glucose, 질소원으로서 2% polypeptone, 무기염으로서 0.1% NaCl을 첨가하였을 때 가장 양호하였고 최적 pH는 6.0이었다. 이상의 조성을 가진 배지를 500$m\ell$용 진탕 플라스크에 100$m\ell$을 넣어 3$0^{\circ}C$ 에서 20시간 호기적 배양을 하였을 때 효소 생산 및 균체량이 최대에 도달하였다. 조효소액은 극히 불안정하여 안정제의 검토가 불가피하였다. 안정제로서는 최종농도가 5% 되도록 ethyl alcohol을 첨가한 경우가 효과적이었으며 pH 안정성은 pH5.0인 acetate buffer에서 가장 안정하였다. 이상의 조건 하에서 조효소액은 20일 이상 동안 약 80%의 잔존활성을 가지고 비교적 안정한 상태로 유지되었다.

• The Korean Journal of Physiology and Pharmacology
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• 제7권3호
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• pp.131-142
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• 2003

We have studied mutant forms of Kir2.1 in which an aspartate residue (D172), important for gating by intracellular polyamines, is replaced by one of three basic residues (Arg, Lys or His). Such channels are highly selective for $K^+$, but show inward rectification that is a shallow function of voltage compared with that found in wild type. This inward rectification occurs with a reduced affinity for spermine and persists in the absence of polyamines. Though the unitary current-voltage relation shows some inward rectification, it is insufficient to account for that seen under whole cell recording. Channels open and shut under single channel recording, and changes of $P_{open}$ appear to generate inward rectification. In D172H, the reduction in affinity for spermine is greater when His is protonated at low $pH_i$. The effective valency for spermine is reduced from $3.09{\pm}0.07$ in wild type to $1.95{\pm}0.09$ in D172H at $pH_i$ 6.3. In the presence of dual mutants of Kir2.1, where E224 is also replaced, spermine affinity becomes undetectable. However, channels still show inward rectification and open and shut under hyper- and depolarisation, respectively. We suggest that Kir2.1 channel are able to undergo conformation changes; these changes may be important physiologically in generating inward rectification, the normal parameters of which are set by the binding of polyamines such as spermine.

• Archives of Pharmacal Research
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• 제22권5호
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• pp.464-473
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• 1999

Regulation of phosphcholine-hydrolyzing phosphatase (phosphocholine-phosphatase) activity, purified from bovine brain, was examined under physiological conditions. Various endogenous phosphomonoesters, which were utilized as substrate, inhibited the phosphocoline-phosphatase activity competitively (Ki 5.5-$82.0 {\mu}M$); among phosphomonoesters tested, there was a similar order of capability between the binding affinity of substrate and the inhibitory potency. In addition, phosphate ions also inhibited the phosphatase activity competitively with a Ki value of approximately $16{\mu}M$. Although leucine or theophylline inhibited the phosphatase activity at pH 9.0, their inhibitory action decreased greatly at pH 7.4. The pH-Km and pH-Vm profiles indicate that ionizable amino acids are involved in substrate binding as well as catalysis, alluding that the phosphatase activity may be highly dependent on the intracellular pH. Amino acid modification study supports the existence of tyrosine, arginine or lysine residue in the active site, and the participation of tyrosine residue in the catalytic action may e suggested positively for the susceptibility to the action of tetranitromethane or HOl-generator. Separately, the oxidative inactivation of phosphocholine-phosphatase activity was investigated. Of oxidants tested, HOONO, HOCl, HOl and $ascorbate/Cu^{2+}$ system were effective to inactivate the phosphatase activity. Noteworthy, a remarkable inativation was accomplished by $30{\mu}M$ HOCl in combination with 1 mM Kl. Inaddition, $Cu^{2+}(3{\mu}M) $in combination with ascorbate at concentrations as low as 0.1-0.3 mM reduced the phosphatase activity to a great extent. From these results, it is proposed that the phosphocholine-phosphatase activity may be regulated endogenously and susceptible to the various oxidant system in vivo.

• 한국임상수의학회지
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• 제28권6호
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• pp.571-575
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• 2011

정액 동결 방법들은 지속적으로 향상되어 왔지만 융해 속도에 대한 연구는 여전히 정립되어 있지 않다. 따라서, 본 연구의 목적은 동결 후 융해 속도가 정액의 기능에 미치는 영향을 알아보고자 하였다. 비글견으로부터 채취된 정액은 동결 보존 후 다른 융해 속도 ($37^{\circ}C$/1분 or $70^{\circ}C$/15초)에서 융해 되었다. 융해 후, 운동성, 생존성, 정상 형태율, 형질막 온전성, phosphatidylserine (PS) translocation, 세포내 $H_2O_2$ 수준을 평가하였다. $70^{\circ}C$에서 융해된 정자는 $37^{\circ}C$에서 융해된 정자에 비해 향상된 정자 운동성, 생존성, 정상 형태율, 세포막 온전성, non-PS translocation을 보였으나(P < 0.05), $70^{\circ}C$와 $37^{\circ}C$에서 융해된 실험군간 세포내 $H_2O_2$ 수준에서 유의적인 차이는 나타나지 않았다(P > 0.05). 결론으로, $70^{\circ}C$에서의 융해는 개 정자 동결 후 정자 기능을 증진시켰으며, 적절한 융해 온도는 동결 정자의 기능을 향상시킬 수 있을 것으로 판단된다.

• 자연과학논문집
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• 제14권2호
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• pp.93-102
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• 2004

A yeast strain SL-27 found to produce active intracellular tyrosinase inhibitor was screened from 972 kinds of yeasts. It was identified as Malassezia pachydermatis based on microbiological characteristics. The optimum pH and temperature for the growth of Malassezia pachydermatis SL-27 were pH 7.0 and $37^{\circ}C$, respectively. The optimal culture conditions for the production of tyrosinase inhibitor by Malassezia pachydermatis SL-27 were investigated. The optimal medium cimposition for tyrosinase inhibitor production was determined to be 1.0% casamino acid, 2.0% glucose, 0.1% $KH_2PO_4$, 0.05% $MgSo_{4-}7H20$ and each 0.01 of $CaCl_2$ and NaCl. Optimal initial pH and temperature for the production of tyrosinase inhibitor were pH 5.0 and $30^{\circ}C$, respectively. The maximum tyrosinase inhibitory activity of 84%/mL of cell-free extract was showed after 12 h of cultivation under the optimal culturing conditions.