• Microbiology and Biotechnology Letters
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• v.14 no.5
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• pp.407-413
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• 1986

In an agitated bead reaction system, the enzymatic saccharification of uncooked starch was substantially enhanced. The enhancement mechanism was investigated front the view of the structural aspect of starch. The mechanical impact caused by the movement of the attrition-milling media resulted neither the destruction of microcrystalline structure nor the fragmentation of starch granule. instead, the most distinct phenomenon was the swelling of starch granule up to about 2.5 times, and the swelling mechanism was not similar with that caused by cooking. However, in the case of the enzyme addition in the attrition coupled reaction system, the swollen starch was easily fragmented into the large number of small particles by the synergistic action of the enzyme and milling-media. The exposed surface area of the fragmented particles plays the major role in enhancing the saccharification. The saccharification rate was quite different depending on the source of starch, the reason was discussed in terms of the granular structure of uncooked starches.

• Bulletin of the Korean Chemical Society
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• v.27 no.12
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• pp.2091-2092
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• 2006

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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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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• v.33 no.1
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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.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.160-164
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• 2007

Aminofuroxan derivatives 3 and 4 were prepared by the reaction of chlorofuroxan 2 with butyl and benzyl amines, respectively. E-beam mediated fragmentation of aminofuroxans 3, 4 in mass spectrometer was analyzed in a view of the corresponding alkyne formation.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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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.

• Environmental Mutagens and Carcinogens
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• v.19 no.1
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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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• v.13 no.3
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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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• v.19 no.3
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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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• v.12 no.1
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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.