• 대한수의학회지
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• 제44권3호
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• pp.441-448
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• 2004

DNase activity in Haemonchus contortus reproductive tissue was characterized and compared to that in whole worm. DNase activity in reproductive tissue was detected throughout pHs 4-10 with high activity under acidic conditions. The activity was not inhibited by 10 mM EDTA at pH 5.0, but largely inhibited by pH 7.0. The activity produced DNA fragments with mixtures of 3'-hydroxyls (OH) and 3'- phosphates (P) at each pH. Three distinct DNase activities were identified and had $M_rs$ of 34, 36 and 38.5 kDa in zymograms, which were distinguished according to pH requirement and sensitivity to EDTA. Among them, the 36 kDa reproductive tissue DNase had predominant activity at pH 5.0, but very weak at pH 7.0, and this activity was not inhibited by EDTA at pH 5.0. These characteristics of the 36 kDa reproductive tissue DNase resemble those of classic acidic DNases. In contrast, 36 kDa whole worm DNase activity had high activity at both pH 5.0 and 7.0. While the 36 kDa DNase activity at pH 5.0 was similar in both reproductive tissue and whole worm samples, the activity at pH 7.0 was predominantly detected in whole worm sample. This suggests that the 36 kDa whole worm DNase at pH 5.0 differs from that at pH 7.0. Thus, results indicate that the EDTA-insensitive 36 kDa DNase at pH 5.0 is specific for H. contortus reproductive tissue.

• Asian-Australasian Journal of Animal Sciences
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• 제32권5호
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• pp.701-710
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• 2019

Objective: This study investigated the effect of different acute heat stress (HS) levels on chicken meat quality and ultra-structure. Methods: Chickens were randomly divided into 7 groups to receive different HS treatments: i) $36^{\circ}C$ for 1 h, ii) $36^{\circ}C$ for 2 h, iii) $38^{\circ}C$ for 1 h, iv) $38^{\circ}C$ for 2 h, v) $40^{\circ}C$ for 1 h, vi) $40^{\circ}C$ for 2 h, and vii) un-stressed control group ($25^{\circ}C$). Blood cortisol level, breasts initial temperature, color, pH, water holding capacity (WHC), protein solubility and ultra-structure were analyzed. Results: HS temperatures had significant effects on breast meat temperature, lightness ($L^*$), redness ($a^*$), cooking loss and protein solubility (p<0.05). The HS at $36^{\circ}C$ increased $L^*{_{24h}}$ value (p<0.01) and increased the cooking loss (p<0.05), but decreased $a^*{_{24h}}$ value (p<0.05). However, as the temperature increased to $38^{\circ}C$ and $40^{\circ}C$, all the values of $L^*{_{24h}}$, cooking loss and protein denaturation level decreased, and the differences disappeared compared to control group (p>0.05). Only the ultimate $pH_{24h}$ at $40^{\circ}C$ decreased compared to the control group (p<0.01). The pH in $36^{\circ}C$ group declined greater than other heat-stressed group in the first hour postmortem, which contributed breast muscle protein degeneration combining with high body temperature, and these variations reflected on poor meat quality parameters. The muscle fiber integrity level in group $40^{\circ}C$ was much better than those in $36^{\circ}C$ with the denatured position mainly focused on the interval of muscle fibers which probably contributes WHC and light reflection. Conclusion: HS at higher temperature (above $38^{\circ}C$) before slaughter did not always lead to more pale and lower WHC breast meat. Breast meat quality parameters had a regression trend as HS temperature raised from $36^{\circ}C$. The interval of muscle fibers at 24 h postmortem and greater pH decline rate with high body temperature in early postmortem period could be a reasonable explanation for the variation of meat quality parameters.

• 한국축산식품학회지
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• 제36권1호
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• pp.29-36
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• 2016

This study was performed to investigate the role of pH and temperature postmortem, and to demonstrate the importance of these factors in determining meat quality. Postmortem pH_45min (pH at 45 min postmortem or initial pH) via analysis of Pearson’s correlation showed high positive correlation with pH change pH_c24 (pH change from pH_45min to pH_24h postmortem). However, postmortem pH after 24 h (pH_24h or ultimate pH) had a high negative correlation with pH change, pH_c24, CIE L*, and protein content. Initial temperature postmortem (T_1h ) was positively associated with a change in temperature from 45 min to 24 h postmortem (T_c24) and cooking loss, but negatively correlated with water holding capacity. Temperature at 24 h postmortem (T_24h) was negatively associated with T_c24. Collectively, these results indicate that higher initial pH was associated with higher pH_c24, T_1h, and T_c24. However, higher initial pH was associated with a reduction in carcass weight, backfat thickness, CIE a* and b*, water holding capacity, collagen and fat content, drip loss, and cooking loss as well as decreased shear force. In contrast, CIE a* and b*, drip loss, cooking loss, and shear force in higher ultimate pH was showed by a similar pattern to higher initial pH, whereas pH_c24, carcass weight, backfat thickness, water holding capacity, fat content, moisture content, protein content, T_1h, T_24h, and T_c24 were exhibited by completely differential patterns (p<0.05). Therefore, we suggest that initial pH, ultimate pH, and temperatures postmortem are important factors in determining the meat quality of pork.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2004년도 춘계총회 및 연구발표회 초록집
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• pp.36.3-36.3
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• 2004

• Applied Biological Chemistry
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• 제39권6호
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• pp.437-442
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• 1996

젖갈에서 분리한 유산균 Lactobacillus(L.) casei 2주와 L. pentosus 1주의 균체내 ${\beta}-galactosidase$의 최적 생성조건과 특성을 조사하였다. ${\beta}-galactosidase$의 최적 생성조건 조사에서, L. cosei No.10 균주는 탄소원으로 lactose를, L. Pentosus No.63 균주는 galactose를 1.0% 함유한 초기 pH 7.5의 MRS broth에서 $30^{\circ}C$로 48시간 배양하였을 때로 확인되었다. L. casei No.36 균주는 lactose를 1.0% 함유한 초기 pH 6.5의 MRS 배지에서 $30^{\circ}C$로 48시간 배양하였을 때가 최적 조건으로 확인되었다. 호소의 최적 활성 반응온도는 3 균주 모두 $60^{\circ}C$였으며, L. casei No.10은 $45^{\circ}C$까지, L. pentosus No.63은 $55^{\circ}C$까지 90% 이상의 안정성을 나타내었다. L. casei No.36은 $40^{\circ}C$까지 안정성을 유지하였으나 $55^{\circ}C$에서 60%로 효소활성이 감소하였으며, 따라서 $40^{\circ}C$까지 3균주 모두 90% 이상의 안정성을 나타내었다. 한편 효소활성의 최적 pH는 3 균주 모두 pH 6.5이었으며, L. casei No.10은 $pH\;5.0{\sim}6.0$, L. casei No.36은 $pH\;5.0{\sim}8.0$, 그리고 L. pentosus No.63은 $pH\;6.0{\sim}7.0$에서 각각 90% 이상의 안정성을 보였다.

• 생명과학회지
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• 제6권2호
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• pp.79-86
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• 1996

A bacterium producing pullulanase was from soil, and was identified Bacillus cereus and named as Bacillus cereus JK36. The optimal culture conditions for the efficident production of pullulanase from B. cereus JK36 was obtained by cultivating with the medium composed of 1% pullulan, 1% teast extract, 1% bactopeptone, 0.1% NaH$_{2}$PO$_{4}$, 2H$_{2}$O, 0.02% MgSO$_{4}$\ulcorner7H$_{2}$O at 40$\circ$C, initial pH 6.5 for 70 hours. Using the culture supernatant as crude enzyme, the optimal pH and temperature of the pullulanase of this strain were 6.5 and 50$\circ$C. In effect of pH and temperature on the stability of the enzyme, the enzyme was stable in the range of pH6.0$\sim$9.5 and up to 40$\circ$C, respectively. The hydrolysis product on pullulan was mainly maltotriose.

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.93-100
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• 2020

A bacterial strain inhibiting the growth of Vibrio anguillarum, the causative agent of vibriosis, was isolated from fish intestines. The isolated strain HS36 was identified as Aerococcus urinaeequi based on the characteristics of the genus according to Bergey's Manual of Systematic Bacteriology and by 16S rRNA sequencing. The growth rate and antibacterial activity of strain HS36 in shaking culture were higher than those in static culture, while the optimal pH and temperature for antibacterial activity were 7.0 and 30℃, respectively. The active antibacterial substance was purified from a culture broth of A. urinaeequi HS36 by Sephadex G-75 gel chromatography, Sephadex G-25 gel chromatography, and reverse-phase high-performance liquid chromatography. Its molecular weight, as estimated by Tricine SDS-polyacrylamide gel electrophoresis, was approximately 1,000 Da. The antibacterial substance produced by strain HS36 was stable after incubation for 1 h at 100℃. Although its antibacterial activity was optimal at pH 6-8, activity was retained at a pH range from 2 to 11. The purified antibacterial substance was inactivated by proteinase K, papain, and β-amylase treatment. The newly purified antibacterial substance, classified as a class II bacteriocin, inhibited the growth of Klebsiella pneumoniae, Salmonella enterica, and Vibrio alginolyticus.

• 한국미생물·생명공학회지
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• 제15권5호
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• pp.306-311
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• 1987

황산암모늄 분획, 2차례의 DEAE-Cellulose, DEAE-Sephadex A-50 및 Sephacryl S-200 superfine gel filtration으로 정제한 결과 Streptomyces sp. J-350P의 세포외 adenine deaminase는 0.3%의 수율로서 1764배로 정제되었다. Streptomyces sp. J-350P의 세포외 adenine deaminase는 pH6.5~8.5 사이에서 안정하였고, pH7.0에서 10분간 열처리하였을 때 5$0^{\circ}C$까지는 안정하였다. 효소 활성 최적 pH와 온도는 pH6.5와 35$^{\circ}C$ 였다. Sephacryl S-200 superfine gel filtration 의한 분자량의 측정 결과 본 효소의 분자량은 약 36,000이었다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권4호
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• pp.488-500
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• 2013

The objective of this study was to compare the effectiveness of the protocols for superstimulation of follicular growth in Thai native heifers. Heifers (n = 20) were randomly divided into four groups of five heifers/group. Heifers were given a single dose by i.m. administration of 100 mg Follicle Stimulating Hormone dissolved in polyvinylpyrrolidone (FSHp) at 24 h. Ovum pick up (OPU) occurred at 72 h ($F_{24}O_{72}$ protocol; Group 1) or 96 h ($F_{24}O_{96}$ protocol; Group 2), and at 36 h and OPU at 72 h ($F_{36}O_{72}$ protocol; Group 3) or 96 h ($F_{36}O_{96}$ protocol; Group 4) after follicular ablation. The dynamics of ovarian follicular growth were monitored by twice-daily ultrasonographic examinations. Blood sample collections were performed every 12 h after initiation of treatment for assessment of FSH, E2 and P4 profiles. All heifers were subjected to eight repeated sequential sessions of OPU. The follicular deviation commenced $24{\pm}5.32$ h after follicular ablation in all groups. The circulatory FSH surged quickly from 24 to 36 h (>0.8 ng/ml) after follicular ablation and circulatory estrogen levels steadily increased from 36 h until OPU in all groups. At the end of the OPU sessions, the mean number of aspirated follicles/heifer/session in $F_{36}O_{72}$ protocol (Group 3) and $F_{36}O_{96}$ protocol (Group 4) were higher than in the two other groups (p<0.05). The number of cumulus-oocyte complexes (COCs), cleaved and day 8 blastocysts rates in the $F_{36}O_{72}$ protocol (Group 3) were higher than in the other groups (p<0.05). It can be concluded that a single dose i.m. administration of 100 mg FSHp at 36 h and OPU at 72 h after follicular ablation ($F_{36}O_{72}$ protocol; Group 3) was the most effective protocol for superstimulation of follicular growth for repeated OPU and subsequent in vitro embryo production in Thai native heifers.

• 한국균학회지
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• 제27권6호
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• pp.383-385
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• 1999

Cheese 제조시 부산물로 생성되는 whey를 배지로 사용하여 Aspergillus niger를 이용하여 citric acid를 생산하는데 영향을 미치는 여러 가지 요인 중 중요한 요인인 온도와 pH의 영향에 대하여 고찰하였다 15일간 27, 30, 33, $36^{\circ}C$와 pH 2, 3, 4, 5에서 각각 배양하면서 소비된 lactose의 양과 생산된 citric acid의 양을 측정하였다. 생산된 citric acid의 최대 농도는 33.9 g/l(구연산 생산에 쓰여진 유당을 기준으로 할 때 68.26%)이었으며, shaking speed는 citric acid 생산에 직접 영향을 주기보다는 pellet 형성시 그 형태에 영향을 미치는 것으로 나타났다. 배양 온도가 $33^{\circ}C$, pH는 3일때 가장 많은 양의 citric acid가 생산되었다.