The present study was conducted to investigate the effect of different heights from liquid nitrogen (LN2) vapor on sperm motility and morphology after frozen-thawing. Two ejaculates were collected from 2 fertile Hanwoo bulls (A and B) by using artificial vagina at Hanwoo Research Institute. After collection, ejaculates were transferred to laboratory immediately and diluted with semen extender (Optixcell, France). Sperm dilutions were extended to a final concentration of 40 x 106 sperm/ml, and cooled at 4°C for 4 h and loaded to 0.5 ml straws. The straws were divided into 2 groups. Straws were placed in 3 or 9 cm of LN2 vapor for 14 min and then plunged into LN2 tank and cryopreserved until evaluation. Sperm motility and motility parameters (total motility, VSL with 25μm≥, VCL, VSL, VAP, LIN, STR, WOB, ALH and BCF) were evaluated by sperm class analysis (SCA, IVOS, Spain) after frozen-thawed. In bull A, 3cm group showed higher percentages of total motility, VSL with 25μm and VAP compared those with 9cm group (98.0 vs. 93.4%, 62.4 vs. 54.0% and 98.6 vs. 93.2%, 3 vs. 9 cm, irrespectively; p<0.001). In bull B, frozen-thawed sperm of 3cm group showed higher percentages of VSL with 25μm, VCL, VSL, VAP and BCF compared with those of 9cm group (43.5 vs. 26.0%, 123.8 vs. 111.6 μm, 62.9 vs. 57.3 μm and 81.5 vs. 72.5 μm; 3 vs. 9 cm, irrespectively; p<0.001). The viability and acrosomal integrity of spermatozoa were evaluated by Trypanblue/Giemsa staining method divided into 4 groups; live and intact acrosome (LIA), live and damaged acrosome (LDA), dead intact acrosome integrity (DIA), dead damaged acrosome (DDA). In bull A, frozen-thawed sperm of 3 and 9cm groups showed no significant difference in LIA, LDA, DIA and DDA. In bull B, 3 cm group showed higher LIA and lower DIA compared with those of 9 cm group (73.2 vs. 23.7% and 23.7 vs. 32.2%, 3 vs. 9 cm, irrespectively; p<0.001). We suspected that 3 cm vapor on LN2 vapor might be affected positively spermatozoa viability and acrosomal integrity compared with 9 cm group. In conclusion, semen freezing procedure in the present study will improve sperm quality after frozen thawing.

To replace methyl bromide (MeBr) due to its ozone depletion properties and the life-threatening to related worker as well as fumigators, ethyl formate (EF) fumigation on exported and imported fruits and vegetables has been developed by QIA in Korea since 2005. The benefits of using ethyl formate (EF) fumigant is considered as the safest practice among the commercially available chemical alternatives. The issues was that the cylinderized EF with carbon doxide (CO2) is not enough to extend their applications in terms of fumigation cost. We have developed the cost-effective liquid EF applications with nitrogen gas and demonstrated in quarantine trials (10m3) on imported bananas. We showed the new 35 gm-3 of EF applications with inert gas (nitrogen), were completely control all stage of citrus mealybug (Planoccous citri) for 4hr fumigation at 13°C. These applications meet the quarantine guidelines and protocols in terms of efficacies to target pest and safety concern as well as satisfactions of consumers showing no damages to imported bananas. Extensively, this cost effective EF technology could be acceptable to other fruit and vegetable commodities to reduce the fumigation costs and green house gas (CO2).

LNGC 주기관의 크랭크 챔버 내 유증기 폭발 방지를 위해 기존의 이산화탄소 가스인젝터가 부착된 오일미스트 감지기 외에 불활성가스 시스템을 설치할 필요가 있다. 특히, LNGC 선박은 액체질소를 손쉽게 확보할 수 있는 장점이 있기 때문에 액체질소를 이용한 불활성가스 시스템을 도입하기 위한 설계 기초 단계로서 해석적 연구를 시행하였다. 또한 액체질소 최소 소모량 시스템을 개발하기 위하여 층상류 모델을 적용하였으며, 층상류 흐름에 미치는 유로관경, 포화압력과 선박동요에 따른 배관 기울기 등의 영향에 대해서도 조사하였다. 또한 질소와 같은 극저온 유체들과 여기에 사용된 예측 모델과의 비교 검토를 통하여 극저온 유체에 대해서도 모델의 유효성을 검증하였으며, 액체질소 불활성가스 시스템의 액체질소를 가스로 상변환 시키는데 소요되는 가열기의 열부하도 예측할 수 있었다.

The effects of cryoprotectants (glycerol, DMSO and ethylene glycol) and the concentrations (0, 0, 25, 0.5and 1.0 M) of sucrose in the diluent on the is vitro survival of mouse morulae froaen rapidly in liquid nitrogenvapour were examined. When the embryos were equilibrated in 1.5 M cryoprotectants +0.25 M sucrose in one-step or in 3.0 M cryoprotectants +0.25 sucrose in two-step and diluted with 0, 0.25, 0.5, or 1.0 M sucrose solution after thawing, high survival rates were obtained in ethylene glycol (48.0% to 88.2 %) or in glycerol (35.0 % to 77.8 %). These results show that 1.5 M ethylene glycol is a highly efficient cryoprotective agent for the rapid freezing of mouse morula embryos and 0.5 M sucrose was optimal concentration in the diluent after thawing.

This study investigates the changes in ammonia fluxes, pH and total nitrogen of liquid ferrous sulfate-treated litter over 5 weeks. A total of 200 broiler chicks (Arbor Acres, 1 d old) was separated into two treatment groups (0 g and 100 g liquid ferrous sulfate/kg litter) with four replications of 25 birds in each group. Liquid ferrous sulfate was sprayed on the litter by using a small sprayer. There was no difference (p>0.05) in the ammonia fluxes observed between the control and liquid ferrous sulfate treatment groups at 0, 1, and 5 weeks, except for 2, 3 and 4 weeks. At 5 weeks, the litter pH and total nitrogen content did not show any difference (p>0.05) between the control and liquid ferrous sulfate treatment groups. In conclusion, the use of liquid ferrous sulfate is not a suitable for use in poultry litter to reduce ammonia and pH or improve the total nitrogen content.

Background : Ginseng seeds are one of short-lived seeds species which loose their viability easily in the condition of conventional storage. Cryopreservation using liquid nitrogen (LN) has been recommended as a alternative storage for this kind of germplasm short lived or dessiccation-sensitive. This study was performed to find out whether cryopreservation could assure initial viability not only for seeds with high germination rate but also for seeds with low germination rate (in aging process). Methods and Results : In this work, 3 cultivars of dehisced ginseng seeds were artificial aged in the condition of 40℃, 95% RH during 6 hours with 3 hours-interval. The germination rate of ginseng seeds was decreased to the range of 71 - 94% of initial viability by artificial aging treatment. After 24 hours of vapor-LN exposure on both of artificial aged and non treated seeds as a cryopreservation, germination rate for each cultivar was decreased with the range of 76 - 95% of initial viability. While the decreasing patterns of germination rate for each cultivar showed similar curves between before and after vapor-LN exposure, the aging effects could be slightly little by cryopreservation for 3 cultivars of ginseng seeds. Conclusion : From the above results, we may suggest that cryopreservation could be recommened for storage tool of dehisced ginseng seeds even with low viability also and expected to make slower seed aging process during preservation period through further study.

The roots of Platycodon grandiflorum has been widely used as a crude drug or a food stuff. Unfortunately, the output and the quality is not regular and highly dependent on the cultivation area and cultivation method. Therefore, seedling cultivation study of this plant under structure with various fertilizer supply was performed. As a result, significant big difference between ammonia nitrogen and nitrate nitrogen content was shown in the root at seedling stage while the difference was not significant in the aerial parts. Fresh weight of the root (7.73 g plant-1) was higher in the group treated with three major nutrients (N, P and K) than in those treated with three major nutrients and calcium or magnesium or both calcium and magnesium, and non-treated group (2.69 g plant-1). Total nitrogen content was recognized to be significantly correlated with root weight, plant height, number of leaves and weight of aerial parts. Ammonium nitrogen content was more correlated the growth of P. grandiflorum than nitrate nitrogen. For phosphoric acid, significant correlation was also shown with the four growth factors.

자작나무 식물유전자원의 효과적인 장기보존 방안을 구명하기 위해 동결전처리 된 겨울철 동아를 건조처리에 의해 초저온보존 시험하여 다음과 같은 결과를 얻었다. 자작나무 동아는 내동성이 최고조에 달한 1월 20일경의 함수율이 42.43%로 가장 낮게 나타났다. 1월 20일에 채취한 동아를 10분간의 건조처리 와 5~-20℃까지 1분당 1℃ 하강조건으로 완속동결 전처리하여 -196℃의 액체질소에 초저온 보존한 경우의 세포생존율은 83.33%로 가장 이상적인 처리조건으로 조사되었다. 자작나무 동아의 시료조제는 동아에 약간의 목질부 조직을 붙여 초저온 보존하는 경우에 86.7%로 세포생존율이 높게 나타났다. 24시간 이상 액 체질소에 초저온 보존한 자작나무 동아는 40±5℃의 온수 중에서 급속 해동하는 경우가 86.6%의 세포생존율을 비롯하여 60%의 식물체 재생율을 나타내어 본 실험에서 가장 효과가 좋은 것으로 조사되었다.

컴퓨터 세포동결기를 이용하여 생쥐 배아를 동결할 때 액체질소 (L)의 분사속도가 해빙 후 배아의 미세구조, 기능 및 발달에 미치는 영향을 알아보고자 하였다. 이를 위해 배아는 동결을 하지 않은 대조군 (control) 및 동결군에서 L의 분사속도에 따라 고속분사군 (120 infusion/min group 1), 저속분사군 (50 infusion/min; group 2)으로 나누었다. ICR 계열의 생쥐의 2 세포기 배아를 사용하였으며, 동결 및 해빙은

지황(Rehmannja glutjnosa)에서 종근 저장시 나타나는 병원균의 오염을 배제하면서 종묘를 대량 증식시키는 방법을 개발하기 위하여 액체 배양을 통해 직접 체세포배를 형성하고자 할 때 요구되는 배지, 질소원, 탄소원 및 pH와 배양 기간 중 배지의 성분 변화를 조사하였다. 줄기나 엽병을 접종조직으로 할 경우, 배지내 질소원인 NH4NO3 와 KNO3의 적정비율은 825 mg/1 : 1900 mg/l 이었고, 탄소원으로는 자당이 적합하였으며, 적정 농도는 3% 이었다. 배지로는 1X MS 배지가 적합하였고, 적정 BA 농도는 2.0 mg/l 였는데, NAA와 조합하였을 경우에는 BA 1 mg/l에 NAA를 0.5 mg/l 를 조합한 배지 와 BA 2.0 mg/l 에 NAA를 0.1 mg/l로 첨가한 배지가 체세포배 발생에 효과적이었다. 멸균 전에 pH를 5.7로 조정한 경우에 직접 체세포배의 형성에 효과적이었다. 배양기간 중 배지 내 Ca++와 Mg++이온은 거의 변화가 없었으나, K+이온은 많이 흡수되었다. 배양 3주 째에 자당은 거의 고갈되었고, 과당과 포도당은 3주 째부터 흡수되기 시작하였다.