• Korean Journal of Microbiology
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• v.30 no.3
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• pp.177-180
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• 1992

Among 120 U. maydis strains isolated in Korea 14 different strains containing specific viral dsRNA segments were analyzed for the distribution of dsRNA and the production of toxin protein. Several distinctive dsRNA patterns were identified, 9 cases of P type with typical H, M and L ds RNA and one case of non-P-type, the frequency of a specific isolate was decreased with increasing number of dsRNA segments. The presence of dsRNA had no effect on the cultural or morphological phenotype of the host. Two isolates containing P type dsRNA segments appeared to produce toxin protein (killer strains) which inhibited the growth of 4 isolates (sensitive strain) with different susceptibility. Two killer strains contain unique M dsRNA segment which may code for toxin protein. However, the presence of toxin-sensitive strains among dsRNA-free isolates was similar to that of ds RNA containing strains.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1001-1009
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• 2000

This study is to find the utilization of intermittent aeration system, around S-COD, T-COD, SS, timewise changes of treatment performance, sludge conversion yield, changes of temperature and pH, etc. In consequence of this study, factors of temperature correction showed 1.052 on continuous aeration, and 1.056 on intermittent aeration which is more sensitive to temperature through a minute degree. Meanwhile, sludge conversion yield on intermittent aeration showed lower and more economical than that on continuous aeration. In case of changing pH, treatment water of both reactors worsened slightly in acid but improved in alkali. In general. considering the quality of effluent water, variation pH of effluent water, etc. the case of intermittent aeration was more favorable than that of continuous aeration.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1261-1263
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• 1997

Two kinds of optically-triggered p-i-n switches with planar and V-groove structures have been fabricated with gold-doped silicon. The V-groove device exhibits a higher threshold voltage and is more sensitive to light. The minimum optical power indicates that a certain minimum illumination is required to optically turn on the silicon p-i-n devices.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.36-39
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• 2001

The secondary effects of pencycuron on cell membrane of Rhizoctonia solani AG4 were investigated by the observation of giant protoplast formation and lipid peroxidation. Compared to protoplasts of R. solani R-C (sensitive strain) and Rh-131 (non-sensitive strain) increased in their size by 2.0-3.5 times 12 h after incubation in potato-dextrose broth containing novozyme (7 mg/$m\ell$) and $\beta$-glucuronidase ($60\mu\textrm{g}/$\textrm{ml}) with 0.6 M mannitol (pH 5.2). The increase of protoplast size in R-C was slightly inhibited from $13.8\textrm{mg}/\textrm{ml}$ without pencycuron to 10.3 ${\mu}{\textrm}{m}$ with 1.0$\mu\textrm{g}$/$m\ell$ of pencycuron. However, the size of giant protoplast of Rh-131 was not affected by the pencycuron treatment. Both strains R-C and Rh-131 did not exhibit the lipid peroxidation 12 h after the application of 1.0 $\mu\textrm{g}$/$m\ell$ pencycuron. The remarkable peroxidation of membrane lipid was observed only in R-C 24 h after pencycuron application, but not in Rh-131. Althought the inhibition of giant protoplast formation and the membrane lipid peroxidation were observed only in the sensitive strain R-C by pencycuron, it is difficult to conclude that these are the primary mechanism of pencycuron. The mild activity of pencycuron on the inhibition of giant protoplast formation and late membrane lipid peroxidation in the fungicide-sensitive strain did not noincid with the dramatic activity of pencycuron in R. solani. Therefore, our results suggest that inhibition of giant protoplast formation and membrane lipid peroxidation is the secondary effect of pencycuron.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.505-509
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• 2006

Membranes prepared from Bacillus cereus KCTC 3674, grown aerobically on a complex medium, oxidized NADH exclusively, whereas deamino-NADH was little oxidized. The respiratory chain-linkedNADH oxidase system exhibited an apparent $K_m$ value of about $65\;{\mu}M$ for NADH. Interestingly, the activity of NADH:DCIP oxidoreductase on NADH oxidase system was decreased remarkably by $Na^+$ or $K^+$, and its optimal pH was 5.5. The activity of NADH:DCIP oxidoreductase was very resistant to the respiratory chain inhibitors such as rotenone, capsaicin, and $AgNO_3$, whereas it was inhibited by about 40% with $40{\mu}M$ 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO). From the results, we suggest the possibility that the aerobic respiratory chain-linked NADH oxidase system of B. cereus KCTC 3674 may possess the HQNO-sensitive NADH:DCIP oxidoreductase lacking an energy coupling site.

• Archives of Pharmacal Research
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• v.26 no.12
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• pp.1047-1054
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• 2003

Molecular chaperones have a crucial role in the folding of nascent polypeptides in endoplasmic reticulum. Some of them are known to be sensitive to the modification by electrophilic metabolites of organic pro-toxicants. In order to identify chaperone proteins sensitive to alkyators, ER extract was subjected to alkylation by 4-acetamido-4 -maleimidyl-stilbene-2,2 -disulfonate (AMS), and subsequent SDS-PAGE analyses. Protein spots, with molecular mass of 160, 100, 57 and 36 kDa, were found to be sensitive to AMS alkylation, and one abundant chaperon protein was identified to be protein disulfide isomerase (PDI) in comparison with the purified PDI. To see the reactivity of PDI with cysteine alkylators, the reduced form ($PDI_{red}$) of PDI was incubated with various alkylators containing Michael acceptor structure for 30 min at $38^{\circ}C$ at pH 6.3, and the remaining activity was determined by the insulin reduction assay. Iodoacetamide or N-ethylmaleimide at 0.1 mM remarkably inactivated $PDI_{red}$ with N-ethylmaleimide being more potent than iodoacetamide. A partial inactivation of $PDI_{oxid}$ was expressed by iodoacetamide, but not N-ethylmaleimide (NEM) at pH 6.3. Of Michael acceptor compounds tested, 1,4-benzoquinone ($IC_{50}, 15 \mu$ M) was the most potent, followed by 4-hydroxy-2-nonenal and 1,4-naphthoquinone. In contrast, 1,2-naphthoquinone, devoid of a remarkable inactivation action, was effective to cause the oxidative conversion of $PDI_{red}$ to $PDI_{oxid}$. Thus, the action of Michael acceptor compounds differed greatly depending on their structure. Based on these, it is proposed that POI, one of chaperone proteins in ER, could be susceptible to endogenous or xenobiotic Michael acceptor compounds in vivo system.

• Journal of Microbiology
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• v.33 no.3
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• pp.244-251
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• 1995

An extracellular protease of Salmonella schottmulleri was purified from culture filtrate by using 0-75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, Ultrogel HA chromatography and Sephacryl S-200 HR molecular sieve chromatography. To measure enzyme activity, synthetic dipeptide substrate (CBZ-arg-arg-AFC) with low molecular weight was employed as substrate. The molecular weight of the purified enzyme was approximately 80 kDa when determined by gel filtration on Sephacryl S-200 HR and 73 kDa when estimated by SDS-PAGE. The isoelectric point was 5.45. The activity of the purified enzyme was inhibited by metal chelating agesnts such as EDTA and 1.10-phenanthroline. The divalent cations, such as Ca$\^$2+/, Zn$\^$2+/, Fe$\^$2+/, Mg$\^$2+/ enhanced its activity. These results suggested that it was a metalloprotease. It had a narrow pH optimum of 6.5-7.5 with a maximum at pH 7.0 and a temperature optimum of 40.deg.C. It was stable at least for 1 week at 40.deg.C and maintained its activity for 24 hours at 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium dodecyl sulfate (SDS) and was inactivated in a dose-dependent manner. However, it was resistant to Triton X-100 and the activity was enhanced to 32.3% with treatment of 0.025% Triton X-100.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.2
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• pp.171-183
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• 1992

In this paper, the behaviour of cavitation erosion, influence of corrosion and corrosion control on slide bearing metals for internal combustion engine were investigated, and this experiment was done by the vibratory cavitation erosion tester. The main results obtained are as follows: 1. With decreasing the space between horn and specimen, the weight loss and its rate increased step by step. But the weight loss and its rate of 0.2mm space decreased conversely more than that of 0.4mm space at early stage. 2. The weight loss and its rate with change of pH were appeared to the order of pH2>pH12>pH7>pH4. And the weight loss and its rate at pH 4 decreased at best. 3. The weight loss and its rate by cavitation erosion for bearing metals were shown to the order of W.M7>W.M1>K.M4. 4. There appeared mainly small pit hole at pH2, and appeared the pit of netting thread type at pH12 by the results of the damaged surfaces at pH2 and pH12 environments that were sensitive to cavitation erosion. 5. With increasing the viscosity of lubricating oil, the weight loss rate by cavitation erosion became dull at the space below 0.5mm. 6. The protective efficiency of cavitation erosion-corrosion is superior inhibitor of chormate(25 ppm) to cathodic protection.

• KSBB Journal
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• v.13 no.6
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• pp.693-699
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• 1998

The relationship between bioluminescence of immobilized Photobacterium phosphoreum and toxic substances was investigated to monitor toxic substances in aqueous solution. The sodium alginate was used as an immobilization matrix. A bioluminescence intensity was maximum when OD660 for cell concentration were between 1.0 and 1.2 and the biolumescence was stable at the pH range of between 6.0 and 8.0. The optimum concentration of alginate for immobilization was found to be 5.0%(w/v) in which dilution was carried out with 2.5%(w/v) NaCl solution that is an optimum environmental condition for the growth of P. phosphoreum. The bioluminescence intensity responded against the toxic substances was proportional to the concentration and a regression curve were established with linearity by using specific bioluminescence reduction rate and Gamma values. It was also found that the response was very rapid and sensitive. The response with such rapidity and sensitivity is a very important factor for the real time monitoring. The immobilized cells showed higher sensitive response to the toxic substances than free cells.

• Journal of Life Science
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• v.14 no.4
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• pp.582-588
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• 2004

Eighty one bacterial strains of parathion degrading bacteria were isolated from soil samples that were contaminated with pesticide in Daejeon area. Among them, one bacterial strain was finally selected in media containing parathion as the sole source of carbon and energy, and this strain was identified as Pseudomonas rhodesiae H5 through physiological and biochemical tests, and analysis of its 16S rRNA sequence. Pseudomonas rhodesiae H5 was able to utilize various carbohydrates but did not utilize sorbose as sole carbon source. Pseudomonas rhodesiae H5 was resistance to ampicillin, spectinomycin, and mitomycin C but sensitive to kanamycin and chloramphenicol. And this strain showed high resistance up to several milligrams of heavy metals such as $BaCl_2$, LiCl, and $MnSO_4$. Optimal growth condition for temperature and pH of P. rhodesiae H5 was 3$0^{\circ}C$, and pH 7.0, respectively. It can be presumed that P. rhodesiae H5 hydrolyzed an organophosphate bond of parathion, forming p-nitrophenol, and then metabolized via ortho-ring cleavage mechanism.