• 한국미생물·생명공학회지
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• 제14권5호
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• pp.407-413
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• 1986

분쇄마찰매체에 의한 무증자 생전분의 효소당화촉진 mechanism을 전분의 구조적 측면을 중심으로 규명하였다. 당화촉진 효과를 줄 수 있는 수준의 분쇄마찰매체의 기계적 교반운동은 생전분의 미세결정구조(microcrystalline structure) 파괴는 물론 전분입자를 붕괴 (fragmentation) 시키는 효과도 없었다. 생전분 입자구조 변화의 중요한 특징은 입자구조의 팽윤(swelling) 현상으로써 팽윤된 전분은 보수능력이 2.5배 정도까지 증가되었다. 이와 같은 기계적 충격에 의한 전분입자의 팽윤현상은 가열호화에 의한 $\alpha$-전분화에 따른 팽윤현상가는 상이하였다. 생전분을 장시간 bead-milling하여 전처리하며 팽윤시킨 생전분은 당화가 촉진되었으나 bead와 효소를 동시에 첨가시킨 경우의 당화속도와 수율에는 미치지 못하였다. 분쇄마찰 반응계에서 효소를 첨가 무증자 전분을 당화시킬 경우에는 생전분입자 2시간 전후하여 수많은 입자로 fragmentation되었다. 생전분의 당화촉진 mechanism은 분쇄마찰매체에 의하여 전분입자가 균열팽윤되고 이 팽윤된 생전분은 보다 쉽게 효소작용을 받아 침식되며 이 침식된 전분입자는 분쇄마찰매체에 의하여 더욱 가속적으로 fragmentation되어 효소작용이 촉진된다고 판단된다. 옥수수, 감자, 고구마 등 각종 생전분은 그 종류에 따라 분쇄마찰 반응계를 활용한 무증자 당화에 많은 차이가 있었으며 이를 전분입자의 구조와 연결시켜 고찰하였다.

• Bulletin of the Korean Chemical Society
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• 제27권12호
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• pp.2091-2092
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• 2006

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.459-463
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• 2009

Furoxanaldehydes possessing phenyl or alkenyl groups at the 3- or 4-position of the furoxan ring were designed for alkyne formation on a solid surface. Furoxans 2 and 3 were prepared from the corresponding alkenes 2a and 3a by the reaction with NaN$O_2$ in acetic acid. Furoxan 4, in which the furoxan ring is conjugated with a double bond, was prepared from bis(bromomethyl)benzene 4a in 5 steps using the Wittig reaction of aldehyde 1 as the key step. The electron beam-mediated fragmentation of furoxanaldehydes 1-4 in a mass spectrometer was exploited by focusing on alkyne formation on the solid surface. The fragmentation of furoxan 3 possessing diaryl groups afforded diarylacetylene at high efficiency, suggesting that the aryl group conjugated with the furoxan ring could facilitate alkyne formation with the evolution of NO.

• Reproductive and Developmental Biology
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• 제33권1호
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• pp.49-54
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• 2009

The current study was designed to evaluate the effects of the reactive oxygen species (ROS) generated with a xanthine (X) and xanthine oxidase system (XO) on sperm function and DNA fragmentation in porcine spermatozoa. ROS were produced by a combination of $1,000{\mu}M$ X and 50 mU/ml XO. The ROS scavengers such as superoxide dismutase (SOD) (200 U/ml) and catalase (CAT) (500 U/ml) were also tested. Spermatozoa were incubated for 2 hours in BWW medium with a combination of X-XO supplemented with or without antioxidants at $37^{\circ}C$ under 5% $CO_2$ incubator. Ca-ionophore-induced acrosome reaction, the proportion of swollen spermatozoa under hypo-osmotic condition, malondialdehyde formation for the analysis of lipid peroxidation, and the proportion of DNA fragmentation were determined after 2 hours incubation. The action of ROS on porcine spermatozoa resulted in decreased Ca-ionophore-induced acrosome reaction and membrane integrity, increased the formation of malondialdehyde, and the proportion of sperm with DNA fragmentation(p<0.05). The toxic effects caused by ROS were completely alleviated by CAT in terms of sperm function and characteristics, however SOD did not serve the same scavenger effect as CAT. To conclude, the ROS can cause significant damage to porcine sperm functions and characteristics, which can be minimized by the use of antioxidants.

• 대한화학회지
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• 제51권2호
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• pp.160-164
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• 2007

고체상 표면에서 퓨록산 화합물의 박막생성을 위하여 클로로퓨록산 2와 butyl 및 benzyl amine과 반응시킨 아미노퓨록산 3,4를 합성하고 이들 아미노퓨록산 화합물을 질량분석기에서 전자빔에 의한 분해반응을 분석하여 알카인의 생성에 대한 효율성을 살펴보았다.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.260-262
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• 2004

In agreement with the results of previous MP2 calculations by Sauers, B3LYP, CASSCF, and CASPT2 calculations on the parent 2-carbena-1,3-dioxolane show that it fragments to ethylene plus $CO_2$ by a concerted pathway with only a small energy barrier. Not only is fragmentation via stepwise C-O bond cleavage computed to be a much higher energy pathway, but the singlet diradical that would be an intermediate along such a reaction path is not even computed to be a local minimum on the potential energy surface.

• 한국환경성돌연변이발암원학회지
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• 제19권1호
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• pp.34-38
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• 1999

Fumonisin B1 is a secondary metabolite of Fusarium moniliforme, a contaminant of corn and corn product. Fumonisin B1 has been shown to be responsible for major toxicological effects of the fungus in rats, horses, and pigs. Fumonisin B1 induced λ DNA fragmentation, which was increased with incubation time, reducing agent NADPH and metal ion (Cu2+). The DNA damage was inhibited by dimethyl sulfoxide (DMSO) or mannitol as radical scavenger for free radicals. DNA fragmentation, induced by fumonisin B1 in the presence of 1 mM NADPH and 0.1 mM CuCl2, was inhibited by 100 mM DMSO. By the in vitro reaction of fumonisin B1 with supercoiled plasmid pBR322 DNA, plasmid DNA was relaxed, eventually linearized in the agarose gel electrphoresis. From rifampicin sensitive E. coli CSH138 in bacterial mutagenesis system, the rifampicin resistant E. coli mutants were obtained by fumonisin B1. These results suggest that fumonisin B1 may be a possible environmental mutagen in bacterial mutagen assay system.

• Toxicological Research
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• 제13권3호
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• pp.187-191
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• 1997

Cell death induced by polychlorinated biphenyls (PCBs), environmental toxicant, was investigated in mouse splenocytes. The fragmentation of intact DNA, a parameter of apoptotic cell death, was evaluated qualitatively by agarose gel electrophoresis analysis and quantitatively by diphenylamine reaction method. PCBs induced apoptotic cell death of splenocytes in a dose- and time- dependent manner. The effect of serum on the apoptotic cell death induced by PCBs was also investigated. The DNA fragmentation induced by PCB treatment in serum-free medium was clearly inhibited by an addition of serum to the culture medium. The decrease of DNA fragmentation due to serum addition was accompanied with the increase of cell viability.

• Environmental Analysis Health and Toxicology
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• 제19권3호
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• pp.251-259
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• 2004

Xenoestrogens are chemicals with diverse structure that mimic estrogen. Bisphenol A, a monomer of polycarbonate and epoxy resins, has been detected in canned food and human saliva. Bisphenol A stimulate cell proliferation and induce expression of estrogen -response genes in vitro. The purpose of the this study was to evaluate cell proliferation of bisphenol A in the presence of a rat liver 59 mix contaning cytochrome P450 enzymes and Cu (II). The fragmentation of intact DNA, a parameter of apoptotic cell death, was evaluated quantitatively by diphenylamine reaction method. Bisphenol A induced apoptotic cell death in a dose-dependent manner The effect of radical scavenger on the apoptotic cell death induced bisphenol A was investigated. The DNA fragmentation induced by bisphenol A was significantly inhibited by addition of radical scavenger to the culture medium. This indicated that elevated oxidative stress caused by imbalance between the production and removal of free radicals occurred in cells. Taken together, these results suggest that free radical reacts with Cu (II) leading oxidative stress.

• Toxicological Research
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• 제12권1호
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• pp.17-20
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• 1996

The effect of Fumonisin B1, a mycotoxin produced by Fusarium moniliforme on bacterial viruses P1 and Lambda, was investigated by the virus plaque assay. Fumonisin B1 inhibited the P1 viral multiplication in the concentration range from $100{\mu}g$/ml to $400{\mu}g$/ml. The inhibition was Fumonisin B1 concentration-dependent. Another bacterial virus Lambda multiplication was also inhibited by lower concentration of Fumonisin B1 ($10{\mu}g$/ml~$50{\mu}g$/ml). This inhibition was dependent on Fumonisin B1 and on virus-Fumonisin B1 reaction time. Sensitivity of bacteriophage Lambda to Fumonisin B1 was higher than that of P1 virus. Lambda vital DNA was treated in vitro with Fumonisin B1 at various concentration. Significant DNA fragmentation by Fumonisin 191 was observed in the agarose gel electrophoresis. Lambda viral DNA was partially digested even in the Fumonisin B1 $10{\mu}g$ and the level of its fragmentation was dependent on Fumonisin B1 amount up to $30{\mu}g$ per assay.