• 한국양식학회지
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• 제17권1호
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• pp.8-11
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• 2004

Milt of the catfish was stripped into immobilizing solution containing 175 mM NaCl and 30 mM Tris at pH 7.8 and was successfully cryopreserved after a stepwise freezing procedure. After stepwise thawing, motility of spermatozoa was slightly lower than that of fresh sperm. Batches of 40-80 eggs were fertilized with cryopreserved spermatozoa, after thawing and activation in solution containing 50 mM NaCl, 20 mM Tris and HCl at pH 7.8; this resulted in 62.2% fertilization success, compared to 70.6 % with fresh sperm.

• Clinical and Experimental Reproductive Medicine
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• 제27권2호
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• pp.191-200
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• 2000

Objective: This study was carried out to compare the effects of the stepwise exposure treatments on the morphological normality, fertilization and blastocyst formation rate of the frozen-thawed mouse mature oocytes by vitrification or ultra-rapid freezing and to use as a fundamental data for the cryopreservation of human oocytes. Materials and Methods: The morphological normality and fertilization rates of the vitrified and ultra-rapid frozen mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were observed. After choosing the 3step exposure treatment groups, we observed the morphological normality and fertilization, blastocyst formation rate of the vitrified and ultra-rapid frozen mouse mature oocytes. Results: The morphological normality and fertilization rates of the vitrified mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were 75%, 85%, 88% and 58%, 61 %, 54% respectively. There were no significant differences among treatments(p>0.05). The morphological normality and fertilization rate of the control was 92% and 65%. There were no significant differences in fertilization rate among control and treatments (p>0.05). The morphological normality and fertilization rates of the ultra-rapid frozen mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were 83%, 83%, 84% and 75%, 63%, 56% respectively. There were no significant differences among treatments (p>0.05). The morphological normality and fertilization rate of the control was 95% and 67%. There were no significant differences among control and treatments (p>0.05). The morphological normality and fertilization rate of the vitrified or ultra-rapid frozen mouse mature oocytes after 3step exposure treatment were 69% and 75%, respectively. The blastocyst formation rate was 60% and 57%. The results did not differ significantly between vitrification and ultra-rapid freezing (p>0.05). Conclusion: As known in the above results, there were no significant differences in the fertilization and blastocyst formation rate of the frozen-thawed mouse mature oocytes by vitrification or ultra-rapid freezing among the control and treatments. It is suggested that vitrification and ultra-rapid freezing method were effective for the cryopreservation of mouse mature oocytes.

• 한국축산식품학회지
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• 제42권3호
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• pp.467-485
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• 2022

Supercooling storage refers to lowering the product temperature below its freezing point without phase transition and has the potential to extend shelf life. Nevertheless, supercooled objects are in a thermodynamically unstable state, and nucleation can occur spontaneously. To achieve supercooling storage, slow cooling and insulation are essential. Hence, a stepwise algorithm for the supercooling storage of pork loins was designed and validated in this study. Pork loins were stored at 3℃, -18℃, and -3℃ (freezing), and supercooled for 16 days. All samples remained in a supercooled state and were unfrozen at the end of storage. Supercooled pork loins were superior in terms of drip loss, cooking loss, and water-holding capacity compared to frozen samples. Additionally, supercooling treatment prevented discoloration, increase of volatile basic nitrogen, and microbial growth. Thus, supercooling of pork loin was achieved using a stepwise program and was effective to maintain meat quality.

• Asian-Australasian Journal of Animal Sciences
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• 제22권3호
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• pp.343-349
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• 2009

This study was designed to simplify a cryopreservation program for embryonic stem cells (ESCs) by selection of cooling method and cryoprotectant. Commercially available mouse E14 embryonic stem cells (ESCs) were cryopreserved with various protocols, and morphology and viability of the frozen-thawed ESCs and their reactive oxygen species (ROS) production were subsequently monitored. Post-thaw colony-formation of ESCs was detected only after a slow freezing using dimethyl sulfoxide (DMSO) by stepwise placement of a freezing container into a $-80^{\circ}C$ deep freezer and subsequently into -$196^{\circ}C$ liquid nitrogen, while no proliferation was detected after vitrification. When the simplified protocol was employed, the replacement of DMSO with a mixture of DMSO and ethylene glycol (EG) further improved the post-thaw survival. ROS generation in ESCs frozen-thawed with the optimized protocol was not increased compared with non-frozen ESCs. The use of fresh mouse embryonic fibroblasts as feeder cells for post-thaw subculture did not further increase post-thaw cell viability. In conclusion, a simplified slow-freezing program without employing programmable freezer but using DMSO and EG was developed which maintains cell viability and colony-forming activity of ESCs during post-thaw subculture.

• 융합정보논문지
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• 제11권1호
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• pp.128-135
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• 2021

바지락 발생배의 냉동보존을 위한 동해방지제의 효과를 규명하기 위하여4종의 보존액, dimethyl sulfoxide, ethylene glycol, glycerol 및 1,2-propanediol을 사용하여 발생배의 생존율을 조사한 결과로, 생존율의 범위는 0-64.3%였고, 대조구의 생존율은 82.3%을 보였다. 발생배의 냉동보존을 위한 프로그래 동결 과정은 최초 25℃에서 10분 동안 유지하다가 자동 냉동보존 프로그램 장치에 의하여 -12℃까지 분당 -1℃씩 조정하였으며 -35℃까지는 분당 -2℃씩 하강시켜 액체 질소통에 스트로우를 넣어 해동 후 관찰한 결과, 바지락 생존율은 DMSO(dimethyl sulfoxide) 2.0M 실험구에서 64.3%로 가장 좋은 결과를 보였다.

• Clinical and Experimental Reproductive Medicine
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• 제16권1호
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• pp.9-14
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• 1989

For the cryopreservation of human embryos this study was accomplished as a preliminary experiment. The purpose of this study is to obtain optimal cryoprotectant, addition and dilution method of cryoprotectant and cooling rate for raising survival of frozon and thawed 2-cell mouse embryos. Seeding was done at $-7^{\circ}C$ and the straw contained embryos was plunged at $-30^{\circ}C$ when the slow cooling was ended. Embryos those developed normally to blastocyst after in vitro culture for over 96 hours were regarded as survival ones. The survival was the rate of number of survival embryos against the recovered embryos. The results are followed : 1. The survivals were 6.3, 71.2 and 67.4% respectively, when Glycerol, DMSO and 1,2-Propanediol were used as cryoprotectant. 2. When sucrose was added in freezing solution, the survival was 69.0%. That was higher than the survival of embryos frozen without sucrose in freezing solution. The difference was not significant. 3. Addition and dilution of cryoprotectant by 4 stepwise raised the survival than by direct, but that was not significant. 4. When embryos were frozen by -0.3, -0.5 and $-1^{\circ}C/min$ before plunged into $LN_2$, the survivals were 67.9, 78.0 and 37.0% respectively. The differnce was significant.

• 한국식품과학회지
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• 제51권1호
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• pp.29-34
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• 2019

본 연구의 침지쌀을 $90-100^{\circ}C$의 온도에서 1, 2차 증숙한 다음 $0-10^{\circ}C$의 냉장저온에서 숙성하는 1단계 처리와 이어 상대습도 85%, $-20^{\circ}C$에서 냉동하는 2단계 그리고 $1-20^{\circ}C$의 상압에서 5 m/s 풍속으로 저온 건조하는 3단계로 구성된 최종 수분함량 30% 인복원용 밥의 제조방법은 기존 열풍건조 대비 관능품질을 향상시키고 상온 3개월 내외의 보관을 가능하게 하였다. 구체적인 효과는 2단계 증숙 및 저온 장시간 건조 과정을 통해 개선된 복원용 밥의 수분함량이 기존 건조밥의 7% 대비 4.3배 높고 쌀알의 고유 형태가 잘 유지되어 있어 취식을 위한 열수 복원시 전반맛, 식감과 외관이 관능평가에서 통계적 유의 있게 향상되었다(p<0.05). 또한 수분 30% 수준은 최적의 관능품질을 나타내면서 미생물 생육을 저해하여 저장성을 향상시키는 조건으로 파악되었다. 이러한 품질 및 저장성 향상 효과가 있는 처리 방법을 멥쌀, 찹쌀, 밀, 콩, 메밀 및 보리 등의 다양한 곡물을 이용한 복원용 밥 제품의 제조에 적용할 수 있어 상업적 활용성이 매우 높다고 할 수 있다.

• Reproductive and Developmental Biology
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• 제35권1호
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• pp.55-60
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• 2011

The objective of this study was carried out to evaluate the efficiency of sperm collection methods on the post-thaw viability of cat semen. The cat semen was collected by artificial virginal (AV) and electronic ejaculate (EE) methods. The composition of semen extender was consisted of Tris-buffer supplemented with 20% egg yolk and 1% P/S antibiotics in Ext I, and more added 8% glycerol, 1.0% Equex STM paste of total volume in Ext II. The collected semen was adjusted the concentration and then diluted in Ext I for optimal concentration. The diluted semen was cooling to $5^{\circ}C$ temperature in refrigerator for at least 2 hrs and then diluted stepwise with Ext II for at least 1 hrs. After an equilibration for 1 hrs, the cooled semen was packaged in 0.5 ml straw and then freezing on the $LN_2$ vapor over 5 cm above from $LN_2$ and then immersed directly in $LN_2$ for cryopreservation. The frozen semen was thawed in $38^{\circ}C$ water for 15 sec and then evaluated the motility, viability, and morphology. Post-thaw semen were calculated the motility by SMI (sperm motility index). The live-dead sperm was evaluated by Eosin-B and morphological evaluation was by Diff-quik kit staining. The post-thaw concentration ($89{\times}10^6$ /ml vs. $128{\times}10^6$ /ml), viability ($22.6{\pm}10.6%$ vs. $37.1{\pm}26.1%$), morphological normality ($27.0{\pm}50.2%$ vs. $45.6{\pm}123.0%$) of EE and AV groups were not significant different, but the post-thaw motility was significant lower in EE than that in AV group ($53.1{\pm}3.6$ vs. $73.6{\pm}5.7$) (p<0.05). In conclusion, semen collection methods did not significant different between EE and AV groups except of post-thaw motility and so both semen collection methods could be applied in feline semen collection methods.