• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1080-1086
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• 2005

Membranes prepared from Vibrio natriegens oxidized both NADH and deamino-NADH as substrates. The maximum activity of the membrane-bound NADH oxidase was obtained at about pH 8.5 in the presence of 0.2 M NaCl, whereas that of the NADH:ubiquinone oxidoreductase was obtained at about pH 7.5 in the presence of 0.2 M NaCl. Electron transfer from NADH or deamino-NADH to ubiquinone-l or oxygen generated a considerable membrane potential (${\Delta}{\psi}$), which occurred even in the presence of $20{\mu}M$ carbonylcyanide m-chlorophenylhydrazone (CCCP). However, the ${\Delta}{\psi}$ was completely collapsed by the combined addition of $10{\mu}M$ CCCP and $20{\mu}M$ monensin. On the other hand, the activity of the NADH oxidase and the ${\Delta}{\psi}$ generated by the NADH oxidase system were inhibited by about $90\%$ with $10{\mu}M$ HQNO, whereas the activity of the NADH:ubiquinone oxidoreductase and the ${\Delta}{\psi}$ generated at the NADH:ubiquinone oxidoreductase segment were inhibited by about $60\%$. Interestingly, the activity of the NADH:ubiquinone oxidoreductase and the ${\Delta}{\psi}$ generated at the NADH:ubiquinone oxidoreductase segment were resistant to the respiratory chain inhibitors such as rotenone, capsaicin, and $AgNO_3$, and the activity of the NADH oxidase and the ${\Delta}{\psi}$ generated by the NADH oxidase system were very sensitive only to $AgNO_3$. It was concluded, therefore, that V. natriegens cells possess a $AgNO_3$-resistant respiratory $Na^+$ pump that is different from the $AgNO_3$-sensitive respiratory $Na^+$ pump of a marine bacterium, Vibrio alginolyticus.

• BMB Reports
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• 제40권1호
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• pp.53-57
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• 2007

The enzymatic properties of NADH:quinone oxidoreductase were examined in Triton X-100 extracts of Bacillus cereus membranes by using the artificial electron acceptors ubiquinone-1 and menadione. Membranes were prepared from B. cereus KCTC 3674 grown aerobically on a complex medium and oxidized with NADH exclusively, whereas deamino-NADH was determined to be poorly oxidized. The NADH oxidase activity was lost completely by solubilization of the membranes with Triton X-100. However, by using the artificial electron acceptors ubiquinone-1 and menadione, NADH oxidation could be observed. The activities of NADH:ubiquinone-1 and NADH:menadione oxidoreductase were enhanced approximately 8-fold and 4-fold, respectively, from the Triton X-100 extracted membranes. The maximum activity of FAD-dependent NADH:ubiquinone-1 oxidoreductase was obtained at about pH 6.0 in the presence of 0.1M NaCl, while the maximum activity of FAD-dependent NADH:menadione oxidoreductase was obtained at about pH 8.0 in the presence of 0.1M NaCl. The activities of the NADH:ubiquinone-1 and NADH:menadione oxidoreductase were very resistant to such respiratory chain inhibitors as rotenone, capsaicin, and $AgNO_3$, whereas these activities were sensitive to 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO). Based on these results, we suggest that the aerobic respiratory chain-linked NADH oxidase system of B. cereus KCTC 3674 possesses an HQNO-sensitive NADH:quinone oxidoreductase that lacks an energy coupling site containing FAD as a cofactor.

• Applied Biological Chemistry
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• 제33권3호
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• pp.264-267
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• 1990

호습쇄의 NADH-ubiquinone oxidoreductase를 강력히 저해하는 합성 piericidin유사체로써 hydroxypyridine 및 hyoxyquinoline 유도체들이 전반적으로 좋은 살균활성을 보였다. 특히, hydroxypyfidine 유도체들은 벼도열병(Pyricularia oryzae)과 보리흰가루병(Erysiphe graminis)에 대해서 높은 살균활성을 나타했다.

• 생명과학회지
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• 제16권3호
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• pp.505-509
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• 2006

호기적으로 자란 Bacillus cereus KCTC 3674로 부터 조제된 막은 NADH만을 산화하고, deamino-NADH는 거의 산화하지 않았다. 호흡쇄와 연계된 NADH oxidase계는 $K_m$ 값이 약 $65\;{\mu}M$ 이였다. NADH:DCIP oxidoreductase의 활성은 $Na^+$또는 $K^+$에 의해 감소되었다. 그 최적 pH는 5.5 였다. NADH:DCIP oxidoreductase의 활성은 rotenone, capsaicin, $AgNO_3$와 같은 호흡저해제에는 매우 저항적 이 였지만, $40{\mu}M$ HQNO (2-heptyl-4-hydroxyquinoline-N-oxide) 존재하에서는 약 40% 저해되었다. 이들 결과로 부터, Bacillus cereus KCTC 3674의 호기적 호흡쇄와 연계된 NADH oxidase계는 energy coupling site가 결여된 HQNO-sensitive NADH:DCIP oxidoreductase를 소유하고 있는 것으로 추정된다.

• 생명과학회지
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• 제18권3호
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• pp.418-421
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• 2008

호기적으로 자란 Bacillus cereus KCTC 3674로 부터 조제된 막은 NADH만을 산화하고, deamino-NADH는 거의 산화하지 않았다. 호홉쇄와 연계된 NADH oxidase계는 $K_m$ 값이 약 65 ${\mu}M$이였다. 한편, NADH oxidase계 중 NADH: menadione oxidoreductase의 효소학적 특성이 조사되었다. NADH: menadione oxidoreductase의 최고활성은 0.1 M KCl (또는 NaCl) 존재 하에서 pH 9.5에서 얻어졌다. NADH: menadione oxidoreductase의 활성은 rotenone, capsaicin, $AgN0_3$와 같은 호흡저해제에 매우 저항적이였다. 그러나 매우 흥미롭게도 NADH: menadione oxidoreductase의 활성은 HQNO (2-heptyl-4-hydroxyquinoline-N-oxide)와 같은 저해제에 의해서는 오히려 촉진되어 졌다.

• Mycobiology
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• 제48권4호
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• pp.326-329
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• 2020

Valuable natural compounds produced by a variety of microorganisms can be used as lead molecules for development of new agrochemicals. Furthermore, high-throughput in vitro screening systems with specific modes of action can increase the probability of discovery of new fungicides. In the current study, a rapid assay tested with various microbes was developed to determine the degree of respiratory inhibition of Saccharomyces cerevisiae in two different liquid media, YG (containing a fermentable carbon source) and NFYG (containing a non-fermentable carbon source). Based on this system, we screened 100 fungal isolates that were classified into basidiomycetes, to find microbial secondary metabolites that act as respiratory inhibitors. Consequently, of the 100 fungal species tested, the culture broth of an IUM04881 isolate inhibited growth of S. cerevisiae in NFYG medium, but not in YG medium. The result is comparable to that from treatment with kresoxim-methyl used as a control, suggesting that the culture broth of IUM04881 isolate might contain active compounds showing the inhibition activity for respiratory chain. Based on the assay developed in this study and spectroscopic analysis, we isolated and identified an antifungal compound (-)-oudemansin A from culture broth of IUM04881 that is identified as Oudemansiella venosolamellata. This is the first report that (-)-oudemansin A is identified from O. venosolamellata in Korea. Taken together, the development of this assay will accelerate efforts to find and identify natural respiratory inhibitors from various microbes.

• Journal of Applied Biological Chemistry
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• 제43권4호
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• pp.185-191
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• 2000

Pest insect control is dependent on about 200 insecticides that work by relatively few mechanisms. The targets they disrupt are mostly involved in the nervous system, respiratory chain, growth and development, or the gut. The major nerve targets are: acetylcholinesterase for the organophosphates and methylcarbamates; the nicotinic acetylcholine receptor for the neonicotinoids; the $\gamma$-aminobutyric acid receptor for several chlorinated hydrocarbons and fipronil; the voltage-gated sodium channel for DDT and pyrethroids. Selection of resistant strains often confers cross-resistance to some or all other insecticides working at the same site. The toxicological properties of different compounds acting on the same target are increasingly considered together, summating the risk even though the compounds are of quite diverse chemical types. Continuing attention is also being given to secondary targets not involved in the primary mechanism of toxicity but instead in side effects that must be considered in the overall safety evaluation. Research on insecticide targets is important in learning to keep up with resistance and changing concepts and policies on safety. These relationships are illustrated by recent studies in the Environmental Chemistry and Toxicology Laboratory of the University of California at Berkeley.

• Applied Biological Chemistry
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• 제34권1호
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• pp.43-48
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• 1991

Menaquinone과 비슷한 구조로써 새로운 quinoline 화합물들은 design하고 합성하여 submitochondria를 이용하여 생리활성을 검정하였다. NADH-ubiquinone oxidoreductase를 저해하는 생리활성은 주로 친유성 부분인 측쇄의 길이에 의존되었다. Quinoline핵의 3위치는 methyl group일 때가 가장 높은 저해활성을 나타냈다.

• Biomolecules & Therapeutics
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• 제28권1호
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• pp.25-33
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• 2020

Several recent studies have reported that reactive oxygen species (ROS), superoxide anion and hydrogen peroxide (H₂O₂), play important roles in various cellular signaling networks. NADPH oxidase (Nox) isozymes have been shown to mediate receptor-mediated ROS generation for physiological signaling processes involved in cell growth, differentiation, apoptosis, and fibrosis. Detectable intracellular levels of ROS can be induced by the electron leakage from mitochondrial respiratory chain as well as by activation of cytochrome p450, glucose oxidase and xanthine oxidase, leading to oxidative stress. The up-regulation and the hyper-activation of NADPH oxidases (Nox) also likely contribute to oxidative stress in pathophysiologic stages. Elevation of the renal ROS level through hyperglycemia-mediated Nox activation results in the oxidative stress which induces a damage to kidney tissues, causing to diabetic nephropathy (DN). Nox inhibitors are currently being developed as the therapeutics of DN. In this review, we summarize Nox-mediated ROS generation and development of Nox inhibitors for therapeutics of DN treatment.

• Journal of Plant Biology
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• 제38권1호
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• pp.87-93
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• 1995

최근에 Synechocystis sp. PCC 6803 중에 한 균주가 고체 한천 배지상에서 일정한 조명(300-1000 lux) 방향을 따라 활주 운동하는 것을 관찰하여 이 종을 S. 6803 PTX라고 명명하고 이의 주광성 운동에 대한 생리학적 특징을 이해하기 위하여 몇 가지 대사 억제제와 신호 전달 차단제의 주광성 운동에 미치는 효과를 조사하였다. DCMU는 광계 II로부터 광계 I의 일차 전자 수용체인 플라스토퀴논으로의 비순환성 광합성 전자전달을 억제하는 억제자로서 $100\;\mu\textrm{M}$의 농도에서는 주광성 운동을 억제하지 못하였다. 그러나 호흡에 의한 전자전달 억제제인 sodium azide를 처리하였을 경우에는 S. 6803 PTX에서 심하게 장해를 받았다. 이러한 관찰 결과는 주광성 운동의 주동력원이 광인산화 과정보다는 호흡에 의한 산화적인 인산화과정에 주로 연관되어 있음을 보여주었다. 또한, 세포를 CCCP나 DNP와 같은 막상의 uncoupler를 처리하였을 때, 세포내 ATP 농도를 저하시키거나 세포질막에 수소 이온의 전기화학구배($\Delta\mu_{H}+$)를 제거시키나, 이러한 화합물들은 주광성 운동에 뚜렷한 영향은 주지 못하였다. 이러한 결과와는 달리, H+-F0F1 ATPase에 민감하게 억제 작용을 나타내는 DCCD나 NBD의 처리는 세포내 ATP만 고갈시키고 막상에서 $\Delta\mu_{H}+$는 그대로 유지시키는 작용을 하는데, 이러한 DCCD나 NBD는 주광성 운동에 대해서는 심하게 억제 현상을 나타내었다. 또한, 특이성 calcium ionophore 중의 하나인 A23187의 처리는 양성 주광성에 심하게 장해를 주었다. 아마도 Ca2+ 유동은 주광운동 방향성의 신호전달 과정에 중요하게 관련되어 있는 것으로 나타났다. 마지막으로 S-adenosyl methionine과 같은 메틸 공여체의 고갈이 S. 6803 PTX 균주의 주광성 반응에 영향을 주는지를 알아보기 위하여 에티오닌을 BG11을 한천 배지에 첨가하였다. 이 생물종의 광운동은 에티오닌의 농도가 증가됨에 따라 일정하게 억제되다가 0.5mM에서 주광성 운동을 완전히 억제시켰다. 이것은 광수용 기작이 Escherichia coil나 Salmonella typhimurium에서 발견된 메틸기 수용 주화성 단백질과 같은 메틸화/탈메틸화 과정에 의하여 조절될 가능성을 보여주고 있음을 의미한다.