• 한국수산과학회지
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• 제29권6호
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• pp.856-861
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• 1996

The occurrence of TTX in ciliated protozoa was investigated in order to clarify tetrodotoxin (TTX) accumulation mechanisms in marine organisms. Tissue culture bioassay, HPLC, and GC-MS analyses confirmed the occurrence of TTX in Euplotes mutabilis and also in bacteria isolated from the culture medium. Fluorescently labeled bacteria (FLB) were prepared with those bacteria, and predation by E. mutabilis was observed. The results indicated that TTX in bacteria can be transferred to higher trophic levels through the food chain.

• 식물조직배양학회지
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• 제25권2호
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• pp.95-98
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• 1998

PI-II cDNA가 도입된 식물발현 벡터인 pGA875를 가진 A.tumefaciens LBA4404를 이용하여 꽃양배추의 하배축 조직에 형질전환하여 식물체를 재분화 시켰다. Dot blot 분석으로 PI-II 유전자가 전사됨을 확인할 수 있었다. 또한 이들 개체를 담배거세미나방 유충을 이용하여 생물검정한 결과 대조구에 비해 형질전환체 잎의 섭식정도가 현저히 떨어지는 것을 알 수 있었다. 개화후 이들 개체의 종자를 받아 후대검정을 실시하였을 때 27,4%가 kanamycin내성을 가진 꽃양배추로 확인되었다.

• Macromolecular Research
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• 제11권5호
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• pp.334-340
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• 2003

In order to fabricate new sustained delivery device of nerve growth factor (NGF), we developed NGF-loaded biodegradable poly(L-lactide-co-glycolide) (PLGA, the mole ratio of lactide to glycolide 75:25, molecular weight: 83,000 and 43,000 g/mole, respectively) film by novel and simple sandwich solvent casting method for the possibility of the application of neural tissue engineering. PLGA was copolymerized by direct condensation reaction and the molecular weight was controlled by reaction time. Released behavior of NGF from NGF-loaded films was characterized by enzyme linked immunosorbent assay (ELISA) and degradation characteristics were observed by scanning electron microscopy (SEM) and gel permeation chromatography (GPC). The bioactivity of released NGF was identified using a rat pheochromocytoma (PC-12) cell based bioassay. The release of NGF from the NGF-loaded PLGA films was prolonged over 35 days with zero-order rate of 0.5-0.8 ng NGF/day without initial burst and could be controlled by the variations of molecular weight and NGF loading amount. After 7 days NGF released in phosphate buffered saline and PC-12 cell cultured on the NGF-loaded PLGA film for 3 days. The released NGF stimulated neurite sprouting in cultured PC-12 cells, that is to say, the remained NGF in the NGF/PLGA film at 37 $^{\circ}C$ for 7 days was still bioactive. This study suggested that NGF-loaded PLGA sandwich film is released the desired period in delivery system and useful neuronal growth culture as nerve contact guidance tube for the application of neural tissue engineering.