• Korean Journal of Microbiology
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• v.30 no.2
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• pp.101-107
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• 1992

Cytochrome c oxida5e from chemotrophically grown R p , geliitinosu was purified by cytochrome c affinity chromatography and DEAE-Sephacel ion exchange chromatography. The molecular weight of the cytochrome c oxidase was approximately 110.000 Da by sephacryl s-300 gel chromatography and approximately 52, 000 Da by SDS-gel electrophoresis, respectively. Therefore. cytochrolne c oxidase of Rps. gehtinosu seems to be dimer. The cytochrome c oxidasc was very sensitive to temperature. It's Km and Vmax were 20 pM and 44 unitlmg protein for horsc heart cytochrome c as a substrate. respectively, and its optimum pH and temperature were 6.4 and 25$^{\circ}$C. respectively. The absorption peaks of the reduced cytochrome c oxidase showed at 554 nm, 523 nm. and 422 nm. The activiiy of cytochrome c oxidase was inhibited by KCN, and NaN3, but not by CO, antimycir~ A. and myxothiazol. The cytochrome c-551 was produced either in phototrophically or chemotrophically grown Rps. gelaiinosci. The rcduced cytochrome c-551 was oxidized by b-type cytochrome c oxidase from Rp.v. gc.lrtino.sc~. Km and Vmax of cytochrome c oxidase was 26 pM and 31 unitlnlg protein For cytochrome c-551 as a substrate. respectively. Thercfore. thc electron transfer chain of chemotrophically grown Rps. glatinosa seems lo be ubiquinol cytochrome bc, complex -'cytochrome c-55lMb-type cytochrome c oxidase+02.

• Korean Journal of Microbiology
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• v.29 no.4
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• pp.243-249
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• 1991

The chromatophore from the chemotrophically grown facultative anaerobic photosynthetic bacterium, Rhodopseudomonas gelatinosa ATCC 17013 was isolated through stepwise sucrose gradient centrifugation. The isolated chromatophore showed high activities of the cytochrome $bc_{1}$ complex and cytochrome c oxidase. The activity of cytochrome $bc_{1}$ complex was completely inhibited by .5$\mu$M antimycin A,10$\mu$M myxothiazol, and that of cytochrome c oxidase was completely inhibited by .$50\mu$M KCM and $100\mu$M $NaN_{3}$but not inhibited by carbon monoxie. The activity of cytochrome c oxidase of th chromatophore was increased by addition of ionophores or protonophores. The reduced-oxidised difference sspectrum of cytochrome $bc_{1}$ complex isolated by affivity chromatography showed the absorption maxima at 553 nm(shoulder at 547 nm), 520 nm, and 418.5 nm, on the other hand, that of cytochrome c oxidase showed .alpha., .betha. and soret peaks at 554 nm, 523 nm, and 421 nm, respectively. The cytochrome c oxidase from chemotrophically grown Rhodopseudomonas gelatinosa seems to be a b-type cytochrome c oxidase.

• Korean journal of applied entomology
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• v.61 no.4
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• pp.641-649
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• 2022

Leaf-rolling moths were collected from soybean fields and identified as Matsumuraeses falcana and Matsumuraeses phaseoli by comparison with laboratory-reared species based on the nucleotide sequence (658 bp) of the mitochondrial cytochrome c oxidase 1 subunit gene (COX1). Ten haplotypes with 0.15-0.46% genetic distance from each other in COX1 were found in 47 samples of M. falcana, in which haplotype A was dominant (approximately 70%). Only one type of COX1 was found in 30 samples of M. phaseoli, and its sequence showed 4.11-4.61% genetic distance from those of M. falcana. Amino acid sequences translated from COX1 were identical in all samples of both species, and they showed synonymous substitutions. Larvae of both species caused damage to soybean leaves and pods and co-occurred simultaneously in the field. The average density of M. falcana was 1.5 times higher than that of M. phaseoli. The results clearly indicate that soybean was the host plant for both species. In addition, Elodia flavipalpis (Diptera: Tachinidae) was found to be a larval parasitoid of Matsumuraeses sp. through identification of the COX1 gene.

• Journal of Applied Biological Chemistry
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• v.60 no.3
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• pp.271-277
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• 2017

Ethyl formate has been used for the control of insect pests by fumigation. However, there were not many reports to show its target site of fumigant toxicity on insect pests since its first use in the agricultural industry. In the present study, we showed the presumable target sites of ethyl formate fumigation in insect pests using Myzus persicae nymphs. After ethyl formate fumigation, the nymphs of this species were collected and the changes at the biochemical and molecular level were determined. The activity of cytochrome c oxidase (COX) was approximately two-fold higher after ethyl formate fumigation. In addition, the expression levels of acetylcholinesterase (AChE) decreased gradually with increasing ethyl formate concentration. These two findings suggested that COX and AChE might be the major target sites of ethyl formate fumigation. In addition to these results, the analysis of lipid content using MALDI-TOF MS/MS identified 9 phospholipids differently generated 2-fold higher in the ethyl formate-treated nymphs than that in the control nymphs, thereby leading to changes in cell membrane composition in M. persicae nymphs. Therefore, the ethyl formate fumigation caused lethal effects on M. persicae nymphs by changing COX activity, AChE gene expression, and phospholipid production.