• 수산해양교육연구
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• 제29권3호
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• pp.702-710
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• 2017

Recently, in many reptiles (14 genera of turtles in five families), common characteristics of incubation temperatures are known to determine the sexes of hatchlings in many species of turtles, including the map turtles, painted turtles and snapping turtles, emys turtle, etc. According to many researcher's reports, in general, incubation at $25^{\circ}C$ (cooler temperatures) produces all or mostly males, however, incubation at $31^{\circ}C$ (higher temperatures) or higher produces all or mostly females. Exceptionally, even cooler temperature ($20^{\circ}C$) produce females, they produced all or mostly females. Accordingly, it is well-known that incubation temperature is the sex determining agent in these turtles. However, this paper presents study of the sex ratio and nest ecology in natural spawning nest: Observations on hatching sex ratios of eggs collected from natural nests of T. sinensis are similar to a previous report of the same genus Trionyx in the soft-shelled turtles. However, this genus (or species) showed some different phenomena to other kinds of turtles such as various kinds turtles mentioned above. After collection of naturally spawned eggs (17 eggs of T. sisnensis) on the natural nests, a laboratory experiment by the constant incubation temperatures was conducted with natural fluctuating soil temperatures in the natural nest with the soft-shelled turtle, T. sinensis. And also laboratory experiments were conducted using constant incubation temperatures of $25^{\circ}C$ (cooler temp.) and $30^{\circ}C$ (higher temp.) with the turtle, T. sinensis. Exceptionally, it was confirmed that the first and second incubation temperatures can't control sex-determination in the freshwater soft-shelled turtle, T. sinensis. The sex ratio approximated 1:1 (${\chi}^2=0.06$, P>0.05 (the Ist experiment). And the sex ratio approximated 1:1 independently of incubation temperature (${\chi}^2=0.33$, P>0.05 (the 2nd experiment). Consequently, temperature has no effect on sex determination in the genus Trionyx in a soft-shelled turtle.

• Fisheries and Aquatic Sciences
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• 제16권1호
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• pp.25-34
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• 2013

Early ontogenic development in Siberian sturgeon Acipenser baerii was documented and the effects of different temperatures on embryonic and prelarval development were examined. Photograph-assisted data on morphogenesis in Siberian sturgeon prolarvae agreed well with published descriptions of their ontogeny and ecological behaviors, although certain aspects of differentiation, such as gill covering and scute development, could be rearing condition-sensitive. The present study provides the first characterization of the transient development of teeth during early larval stages; the pattern was congruent with the transition of prolarvae to exogenous feeding. From examinations of embryonic and prelarval development under different temperature conditions ($12-24^{\circ}C$), developmental speed was inversely related with temperature. Overall, hatchability was higher and hatching events were more synchronized at $20^{\circ}C$ than at lower temperatures. After hatching, similar patterns of temperature-dependency were observed in yolk sac absorption and the evacuation of the pigment plug. Our results suggest that the incubation of Siberian sturgeon embryos and prolarvae at temperatures close to $20^{\circ}C$ would be advantageous in hatcheries, based on reductions in the duration and uniformity of egg and prolarval developmental stages.

• 한국발생생물학회지:발생과생식
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• 제21권1호
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• pp.101-110
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• 2017

On June 14, 2008 (the first experiment) and July 24, 2008 (the second experiment), the shores of the Boseong River and the sandy beaches, Seokgok-myun, Moksadong-myun, Gokseong-gun in Jeollanam Province were investigated and a total of 29 soft-shelled turtle (Tryonyx sinensis) eggs in the natural spawning nest eggs were collected (13 eggs were collected in the first experiment and 16 eggs in the second experiment). The temperatures in the natural spawning nests were $25.9-36.9{\pm}0.5^{\circ}C$, the depth of the eggs was $5.2-7.5{\pm}0.5cm$ as the distance of the average $6.4{\pm}0.5cm$. 29 eggs were scattered at least 0.2 cm interval. Artificial incubation of 29 eggs was conducted in artificial nest boxes in thermo-plastic composition of the incubator, and then incubated at $26.5-35.5{\pm}0.5^{\circ}C$, and an average constant temperature was $31.2-32.1{\pm}1.0^{\circ}C$. The incubation days ranged from 53 to 55. In case of most turtles, incubation at $31^{\circ}C$ (higher temperatures) generally produces all or mostly females, while incubation at $25^{\circ}C$(cooler temperatures) produces all or mostly males. Exceptionally, in case of genus Trionyx, the sex ratio of female : male of T. sinensis of a freshwater soft-shelled turtle was approximately 1:1, which differs from other genera of turtles and makes T. sinensis Strauch only turtles presently known to lack temperature-dependent sex determination.

• Asian-Australasian Journal of Animal Sciences
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• 제31권6호
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• pp.827-834
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• 2018

Objective: The aim of this study was to compare the effects of $36.5^{\circ}C$ and $38.5^{\circ}C$ incubation temperatures on the maturation of bovine oocytes and developmental competence of embryos. Methods: In experiment 1, oocytes were maturated in bicarbonate-buffered TCM-199 for 22 hours in a humidified atmosphere of 5% $CO_2$ in the air at either $36.5^{\circ}C$ or $38.5^{\circ}C$ and nuclear maturation status were determined. In experiment 2, in vitro fertilized oocytes were allocated randomly into synthetic oviductal fluid medium with or without a mixture of 1 mM L-glutathione reduced and 1,500 IU superoxide dismutase and cultured in a humidified atmosphere of 5% $CO_2$, 5% $O_2$, and 90% $N_2$ in the air at $38.5^{\circ}C$ for 8 days. Results: There were no significant differences between incubation temperatures in terms of oocyte maturation parameters such as cumulus expansion, first polar body extrusion and nuclear maturation. Incubation temperatures during in vitro maturation had no effects on developmental competence of embryos, but supplementation of antioxidants increased (p<0.05) developmental competence of the embryos. Blastocysts from oocytes matured at $38.5^{\circ}C$ had comparatively higher inner cell mass, but low overall and trophectoderm cell numbers (p<0.05). Conclusion: The results of present study showed that maturation of bovine oocytes at $36.5^{\circ}C$ may provide a suitable thermal environment for nuclear maturation and subsequent embryo development.

• 한국축산식품학회지
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• 제28권2호
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• pp.154-159
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• 2008

근육단백질과 카제인염 단백질간의 상호작용의 촉매제로서 TGase의 배양시간과 온도에 따른 물성효과를 측정하기 위하여 본 연구를 실시하였다. 돈육 등심부위의 근원섬유단백질을 추출하였고 배양온도는 $4^{\circ}C$, $37^{\circ}C$로, 배양시간은 0, 0.5, 2, 4시간으로 단백질의 열량분석, 점도, 겔 강도, 전기영동상 패턴의 변화를 측정하였다. 단백질열량변화는 각 단백질 별로 열량변화 패턴이 상이하게 나타났으며 근원섬유와 카제인염의 혼합액은 각각의 단백질 피크와 유사하게 나타났고 배양시간과 온도에 따라 차이를 보여 $4^{\circ}C$에 비하여 $37^{\circ}C$에서 열량변화의 차이가 크게 나타났다. 점도의 경우 배양하지 않은 것과 비교했을 때 $37^{\circ}C$에서 2시간 배양했을 때부터 유의적인 차이를 보이며 증가하였다. 근원섬유단백질을 4.5%의 농도로 가열에 의한 겔의 강도를 측정한 결과, 배양시간이나 온도에 따른 뚜렷한 차이를 보이지 않았다. 전기영동의 경우에도 $4^{\circ}C$ 와 $37^{\circ}C$의 배양의 경우 myosin heavy chain과 카제인 염 단백질 분획이 배양시간이 경과함에 따라 점차 감소하였고, 특히 $37^{\circ}C$에서 30분까지는 큰 변화를 나타내지 않았으나 2시간부터 32-34 kDa 분자량을 갖는 카제인 염단백질의 저분자의 밴드가 사라지고 고분자의 biopolymer를 형성하였다. 이상의 결과를 종합하면 $4^{\circ}C$보다 $37^{\circ}C$에서 단백질 분자간의 상호작용에 의한 TGase의 효과가 뚜렷하였으며 $37^{\circ}C$에서 2시간 이상 배양시 TGase에 의한 현저한 물성의 차이를 보인 것으로 평가된다.

• 한국축산식품학회지
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• 제36권3호
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• pp.427-434
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• 2016

Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products.

• 한국환경생태학회지
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• 제37권3호
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• pp.192-197
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• 2023

본 연구는 서울대공원 인공사육장에서 남생이(Mauremys reevesii) 알의 부화온도 차이에 따른 부화기간과 성장에 영향을 주는지 알아보고자 연구했다. 전체 201개의 남생이 알을 26(n=89)℃, 28(n=75)℃ 그리고 32(n=37)℃에서 각각 부화시켰다. 남생이 알의 부화온도와 부화기간은 온도에 따라 유의미한 차이를 나타내었다. 본 연구에서 부화 온도가 높을수록 부화율이 증가하였다. 26℃, 28℃, 그리고 32℃에서 부화한 알의 부화 기간은 각각 66.1(±4.0, n=52)일, 65.3(±3.3, n=44)일 그리고 58.8(±7.7, n=31)일이었다. 부화율은 32℃(83.8%)가 26℃(58.4%)와 28℃(58.7%)보다 상대적으로 높았다. 32℃에서 부화한 14일 된 새끼의 몸무게가 26℃와 28℃에서 부화한 14일 된 새끼의 몸무게보다 높았다. 그렇지만 부화 후 180일과 270일에 새끼의 몸무게는 부화 온도에 따라 큰 차이가 없었다. 본 연구에서 한국산 남생이(M. reevesii) 알의 부화 온도가 부화 기간과 성장 초기 남생이의 체중에 유의한 영향을 미치는 것으로 나타났다.

• 한국수정란이식학회지
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• 제28권3호
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• pp.297-302
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• 2013

Cryopreservation of epididymal spermatozoa offers a potential tool for rescuing genetic material from males of genetically elite populations. Castration, catastrophic injury, sudden death or any other event that makes semen collection or mating impossible may prematurely terminate a stallion reproduction. Stallion epididymal spermatozoa vary widely in the loss of progressive motility, acrosomal integrity, and viability during freezing and thawing. The objective of this work was to investigate the effect of (1) freezing package types on cryopreservation efficiency, (2) thawing temperatures (37, 56 or $70^{\circ}C$) on Computer Assisted Sperm Analysis (CASA) parameters and (3) post-thawing incubation time (0, 1, 2 or 4h) on castrated stallion epididymis. Post-thawed sperm motility ranged between 59.69% and 64.28% ($56^{\circ}C$ and $37^{\circ}C$) in various thawing temperatures. When stallion epididymis sperm was frozen, straw was better than freezing tube on VCL (Velocity of Curvilinear Line) and VAP (Velocity of Average Path) parameter. Higher percentage of motility was observed at $37^{\circ}C$ thawing temperature even though no significant difference was observed among various temperatures. The motility, VCL, ALH (Amplitude of Lateral Head displacement), VAP, BCF (Beat-Cross Frequency) and STR (Straightness index) parameter of post-thawed sperm were significantly decreased by increasing the incubation time for all thawing temperatures. The present study showed that type of freezing package (Straw vs. Freezing tube) was not significantly different on cryopreservation efficiency. Furthermore, stallion epididymal spermatozoa frozen-thawed at $37^{\circ}C$ for 1 min resulted the highest proportion of motility and velocity movement. In addition, motility and viability of frozen-thawed stallion epididymal spermatozoa were also decreased by incubation.

• 한국축산식품학회지
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• 제25권1호
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• pp.84-91
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• 2005

본 연구에서는 EPS 생성 유산균인 S. thermophilus St-Body 1을 발효 온도 및 시간별로 EPS를 분리하여 발효 조건이 EPS 생성에 미치는 영향과 EPS 생성량이 stirred 요구르트의 점도, syneresis, 물성, 관능검사에 미치는 영향에 대하여 조사하였다. pH와 유산 함량 변화는 온도에 따라 다른 경향을 보였으며, 발효 온도가 높을수록 pH 감소가 빠르게 진행되고, 6, 12시간에 많은 유산이 생성되었다. 유당 함량은 발효 6시간 동안에 20∼40%가 이용되었고, 유산균수는 31℃에서 발효한 요구르트가 상대적으로 유산균수가 높은 것으로 나타났다. S. thermophilus St-Body 1은 발효 온도가 낮을수록 더 많은 EPS를 생성하고, 발효 12시간과 24시간에 많은 EPS를 생성하는 것으로 관찰되었다. 점도는 발효 시간이 증가할수록 점도가 증가하였으며, syneresis는 37℃에서 30시간 발효한 stirred 요구르트가 가장 적은 것으로 나타났다. 경도와 접착성은 발효가 진행될수록 증가하는 경향을 보였고, 점착성과 탄력성은 발효가 진행될수록 감소하였다. S. thermophilus St-Body 1로 발효한 요구르트의 관능검사 결과, 37℃, 24시간 발효한 요구르트가 풍미 6.25, 조직 4.25, 외관 3.50으로 가장 높은 수치를 나타내었다.

• 한국버섯학회지
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• 제18권4호
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• pp.317-322
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• 2020

느타리 '흑타리' 품종의 배양 중 고온스트레스에 의해 발생되는 미발이 현상을 구명하기 위하여 배양온도에 따른 생육차이를 조사하였다. PDA 배지에서 '흑타리'의 적정생육온도는 23~26℃였고, 균사생장속도는 '춘추2호'에 비하여 빠른편이었다. 병내 배지온도는 초기에 상승하여 배양 중반에 최고점에 도달한 후 온도가 하강하였다. 배양 온도가 높을수록 배양기간은 짧아졌다. 배양온도 20℃ 처리구에서 배양기간은 25일 정도 소요되었으며, 미발이율은 1.8%, 수량은 139.4 g/병을 나타내었다. 배양온도 24℃ 처리구에서 배양기간은 20일 정도 소요되었으며, 미발이율은 4.2%, 병당수량은 132.1 g/병을 나타내었다. 배양온도 16℃와 28℃처리구에서는 미발이율이 증가되었고 수량이 감소하였다. 이 결과를 바탕으로 농가에서 배양온도와 미발이율의 관계를 조사하였다. 배양실 온도를 18℃로 설정하고 배지품온을 28℃ 미만으로 관리하는 농가는 미발이율이 0.3~0.8%를 나타내었다. 배양실내의 온도가 20℃ 이상이며 환기가 잘 이루어지지 않은 농가에서는 미발이율이 3.5% 정도 발생되었다. 배양실 온도가 19℃이며 배지 최고 품온이 31.3℃까지 상승하는 농가는 미발이율이 8.2%로 높게 나타났다. 배양중 병내부 온도가 28℃이상 상승하고 배양실내의 환기가 잘 이루어지지 않을 경우 미발이율이 증가하고 수량이 감소되는 경향을 보였다. 결과적으로, 배양실은 배지품온이 28℃ 이상 상승하지 않도록 배양실 내부의 공기를 지속적으로 순환시키고, 배양공간에 맞는 최적의 배양량을 넣어 관리하여야 한다.