• Fisheries and Aquatic Sciences
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• 제20권8호
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• pp.17.1-17.8
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• 2017

Somatostatin (SS) and growth hormone-releasing hormone (GHRH) are primary factors regulating growth hormone (GH) secretion in the pituitary. To date, it remains unknown how this rhythm is controlled endogenously, although there must be coordination of circadian manners. Melatonin was the main regulator in biological rhythms, and its secretion has fluctuation by photic information. But relationship between melatonin and growth-related genes (ghrh and ss) is unclear. We investigated circadian rhythms of melatonin secretion, ghrh and ss expressions, and correlation between melatonin with growth-related genes in tiger puffer Takifugu rubripes. The melatonin secretion showed nocturnal rhythms under light and dark (LD) conditions. In constant light (LL) condition, melatonin secretion has similar patterns with LD conditions. ss1 mRNA was high during scotophase under LD conditions. But ss1 rhythms disappeared in LL conditions. Ghrh appeared opposite expression compared with melatonin levels or ss1 expression under LD and LL. In the results of the melatonin injection, ghrh and ss1 showed no significant expression compared with control groups. These results suggested that melatonin and growth-related genes have daily or circadian rhythms in the tiger puffer. Further, we need to know mechanisms of each ss and ghrh gene regulation.

• ALGAE
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• 제37권1호
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• pp.49-62
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• 2022

Water temperature affects plankton survival and growth. The dinoflagellate Shimiella gracilenta survives using the plastids of ingested prey, indicating kleptoplastidy. However, studies on the effects of water temperature on kleptoplastidic dinoflagellates are lacking. We explored the growth and ingestion rates of S. gracilenta as a function of water temperature. Furthermore, using data on its spatiotemporal distribution in Korean coastal waters during 2015-2018, we predicted its distribution under elevated temperature conditions of +2, +4, and +6℃. Growth rates of S. gracilenta with and without Teleaulax amphioxeia prey as well as ingestion rates were significantly affected by water temperature. Growth rates of S. gracilenta with and without prey were positive or zero at 5-25℃ but were negative at ≥30℃. The maximum growth rate of S. gracilenta with T. amphioxeia was 0.85 d^-1, achieved at 25℃, and 0.21 d^-1 at 20℃ without prey. The ingestion rate of S. gracilenta on T. amphioxeia at 25℃ (0.05 ng C predator^-1 d^-1) was greater than that at 20℃ (0.04 ng C predator^-1 d^-1). Thus, feeding may shift the optimal temperature for the maximum growth rate of S. gracilenta from 20 to 25℃. In spring and winter, the distributions of S. gracilenta under elevated temperature conditions were predicted not to differ from those during 2015-2018. However, S. gracilenta was predicted not to survive at some additional stations under elevated temperature conditions of +2, +4, and +6℃ in summer or under elevated temperature conditions of +6℃ in autumn. Therefore, global warming may affect the distribution of S. gracilenta.

• 한국균학회지
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• 제46권3호
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• pp.271-280
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• 2018

외생균근성 버섯균인 송이(Tricholoma)속 균은 현재 인공 재배가 이루어지지 않고 있으며, 성공적인 자원이용을 위해서는 다양한 환경조건에서 균사생장 특성을 규명하는 연구가 선행되어야 한다. 이에 따라 본 연구는 야생버섯 자실체로부터 순수 분리한 4종의 Tricholoma bakamatsutake (가송이), T. fulvocastaneum (구실잣밤나무송이), T. matsutake (송이), T. terreum (땅송이)로부터 물리적, 화학적 환경조건에서 균사생장 특성을 조사하였다. 4종 모두 균사생장에 적합한 물리적 환경으로서 최적 배양 환경 조건은 온도가 $20{\sim}25^{\circ}C$, pH가 4~7, 암 배양 조건인 것을 확인하였다. T. matsutake는 $30^{\circ}C$에서 균사생장이 멈추는 매우 민감한 특성을 보였다. 균사생장에 미치는 화학적 요소 조사 결과, NaCl 농도조건에서 4종의 Tricholoma 모두 1.0% 농도수준 까지 생장이 가능하였다. T. matsutake는 2.0% 농도에서도 균사생장이 가능하였다. 중금속인 카드뮴(50 ppm 농도)과 농약인 emamectin benzoate이 첨가된 배지에서 네 가지 송이속 균의 균사생장이 가장 많이 저해된다는 것을 확인하였다. 중금속구리(Cu) 이온(50 ppm 농도)이 함유된 배지에서는 4종 송이속 균주 모두 균사생장이 거의 저해되지 않았다. T. matsutake는 emamectin benzoate 외에 다른 세 가지 살충제에 대해선 균사생장 억제가 거의 나타나지 않았다. 세포외효소는 T. bakamatsutake와 T. fulvocastaneum만 발색배지에서 Amylase, ${\beta}$-glucosidase 등의 효소활성을 보였다. 본 연구 결과는 4종 송이속 균주의 균사배양에 적합 또는 유해한 환경조건을 구분 할수 있어서 향후 응용 연구에 도움이 될 것으로 기대된다.

• KSBB Journal
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• 제8권3호
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• pp.193-199
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• 1993

공기부양 생물반응기에서 천연 청색 색소원인 쪽 (Poly,앵wm tinctorium) 세포를 대량 배양하기 위한 배양조건을 찾기 위해 영양성분 빛 색소 전 구체를 포함한 배지 성분의 생육에 미치는 영향 과 여러 배양조건에서 세포의 생육 특성에 대하 여 설험하였다. 최적 생육조건과 생육 특성을 규 명하기 위 해 external 1oop와 internal loop 두 가지의 arr-lift bioreactor 종류를 사용하여 14일간 배양하였다. 초기 접종량을 달리한 결과 각 reactor에서 공히 접종량이 0.5-2.5% packed cell volume 보다 많을수록 생육에 좋은 결과를 나타내였다. 초기 당농도의 영향을 살펴보기 위하여 2-4%로 그 조건을 달리하여 14일간 배양한 결과 4% 초기 당농도가 생육에 가장 좋은 조건임을 알 수 있었다. Sucrose는 대수기 초기단계에서 모두 소비되었다. Tryptophan(lmM)을 첨가한 경우 14일 배양 후에 internal loop reactor에서 3.8g/l, external loop reactorr에서 3.5g/l 의 cell mass를 얻었다. Indole을 첨가했을 때에는 세포 생육 저해효과 를 나타내였는데 external과 internal Ioop reactor에서 각각 2.5g/l와 2.2g/l를 얻었다. 무기질소원 으로는 potassium nitrate가 선발되었고, contrl이에 비해 110%d의 생육도 증가가 있였다. 최적 조건 하에셔의 14일간 internal loop bioreactor 배양에서 세포 건조 중량 16.34 g/l를 얻었다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.269-274
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• 1997

Silicon carbide(SiC) epilayers were grown by a thermal CVD(chemical vapor deposition) process, and their crystalline properties were investigated. Especially, the growth conditions of 6H-Sic homoepitaxial layers were obtained using a SiC-uncoated graphite susceptor that utilized Mo-plates. In order to investigate the crystallinity of grown layers, Nomarski photograph, transmittance, XRD, Raman, PL and TEM measurements were used. The best quality of 6H-SiC epilayers was obtained in conditions of growth temperature 1500$^{\circ}C$ and C/Si ratio 2.0.

• 한국결정성장학회지
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• 제13권1호
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• pp.1-4
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• 2003

In the present work we consider morphological structure of the faces of BGO crystals grown by Czochralski technique under the conditions of low temperature gradient (0.1~1 deg/cm) and interconnection between the morphological features of faces at the crystallization front and the formation of defects within the crystal volume. It is demonstrated that the {112} faces retain stability while the growing surface deviates from the crystallographic (112) plane up to 1 degree. At larger deviation, the region of the stable facet growth passes either to the region of macrosteps or to the region of normal growth. depending on conditions.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.275-280
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• 2004

Shape optimization was performed to obtain the precise shape of cutouts including the internal shape of cutouts in laminated composite plates by three dimensional modeling using solid element. The volume control of the growth-strain method was implemented and the distributed parameter chosen as Tsai-Hill fracture index for shape optimization. The volume control of the growth-strain method makes Tsai-Hill failure index at each element uniform in laminated composites under the initial volume. Then shapes optimized by Tsai-Hill failure index were compared with those of the initial shapes for the various load conditions and cutouts. The following conclusions were obtained in this study. (1) It was found that growth-strain method was applied efficiently to shape optimization of three dimensional cutouts in a laminate composite, (2) The optimal shapes of the various load conditions and cutouts were obtained, (3) The maximum Tsal-Hill failure index was reduced up to 67% when shape optimization was peformed under the initial volume by volume control of growth-strain method.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.472-478
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• 1995

Mycelial growth, color difference and productivity of red pigment of beni-koji by Monascus anka KCCM 11832 were examined with respect to it's pigment in submerged culture with various medium and culture conditions. Shaking incubation was more promoted mycelial growth and the production of pigments than that for non-shaking incubation, and red color became ten times deeper. The production of red pigment was the highest when incubated at 25$\circ$C for 7 days in pH 6.0, but mycelial growth was showed the highest at 32.5$\circ$C. The levels of carbon and nitrogen source for maximum red pigment production were 2% rice powder and 0.05% peptone, respectively and the level of peptone for maximum pigment production was lower than that for maximum mycelial growth. Among pigmentation promoting agents tested, MgSO$_{4}$, was found to be suitable for the production of red pigment, and the optimum level was 0.1%.

• 한국수산과학회지
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• 제41권6호
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• pp.446-451
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• 2008

The growth of Porphyridium cruentum and its porphyran polysaccharide production were measured as functions of light intensity, temperature, light quality (fluorescent, blue, red, and green) and nitrate concentration. The optimum light intensity, temperature, and nitrate concentration for the growth of Porphyridium cruentum and for its polysaccharide production were 1,400 lx, $25^{\circ}C$, and 0.03%, respectively. The maximum cell concentration and polysaccharide content under the optimum conditions were 1.95 and 0.23 mg/mL, respectively. Light quality did not influence growth or polysaccharide production. The best results for growth and polysaccharide production were obtained using fluorescent light.

• International Journal of Railway
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• 제5권3호
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• pp.129-134
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• 2012

Contact fatigue damages on the rail surface, such as head checks and squats are a growing problem. The fatigue cracks forming on the contact surface grow according to load and lubricating conditions and may end up breaking the rail. Rail fracture can be avoided by preventing the cracks from reaching the critical length. Therefore, the crack growth rate needs to be estimated precisely according to the conditions of the track and load to develop a maintenance plan against rail damages. Therefore, it is important to understand the mechanism of cracks initiation and growth on a rail due to repetitive rolling contact. In this study, we have investigated the crack growth behavior on the rail surface by using the twin-disc tests and the finite element analysis.