Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A feature of the mitochondrial electron transport chain in plants, some protists and many fungi is the presence of two terminal oxidases, the energy-conserving cytochrome oxidase and another termed alternative oxidase (AOX). AOX branches from the main respiratory chain, directly coupling the oxidation of ubiquinol with reduction of oxygen to water. The AOX genes can be divided into two discrete subfamilies, AOX1 and AOX2. Although AOX has been proposed to play essential roles in stress tolerance of organisms, the role of subfamily AOX2 is largely unknown. In the model green alga Chlamydomonas reinhardtii, two genes have been identified that encode for AOX, AOX1 and AOX2. To test AOX2 transcriptional regulation in this alga, we used a real-time PCR analysis and an artificial microRNA approach. The C. reinhardtii AOX2 gene is up-regulated by oxygen or copper deprivation. Moreover, in dark-adapted unstressed cells, AOX2 is induced. Together, our results imply that the AOX2 gene is a stress-inducible and is regulated by the copper response regulator 1 (CRR1), probably together with yet-unknown regulatory factor(s).
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PMID:New insights into AOX2 transcriptional regulation in Chlamydomonas reinhardtii. 2808 29

The mitochondrial respiratory chain in plants, many fungi and some protists consists of the ATP-coupling cyanide-sensitive cytochrome pathway and the cyanide-resistant alternative respiratory pathway. The alternative pathway is mediated by alternative oxidase (AOX). In unicellular algae, AOXs are monomeric fungi-type proteins. Studies performed in the model plant Chlamydomonas reinhardtii showed that a range of stress factors lead to induction of its AOX1. However, signaling molecules that trigger upregulation of AOX1 have not yet been identified. Here, we were able to discriminate between two alternative oxidases of the alga. In this work, we demonstrated that exposure of C. reinhardtii to nitric oxide (NO) resulted in the up-regulation of AOX1 expression and an increased AOX1 protein. Furthermore, NO-treated C. reinhardtii cells displayed the enhanced AOX1 capacity. We also clearly demonstrated that AOX1 can function in C. reinhardtii when the cytochrome oxidase became inhibited by NO. Although the pathway(s) that leads to increased AOX1 levels and activity upon NO treatment is yet unknown, it is now clear that NO serves as the signal to trigger this regulatory process in C. reinhardtii.
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PMID:Nitric oxide upregulates expression of alternative oxidase 1 in Chlamydomonas reinhardtii. 2909 84

This study was designed to analyze the effect of the mitochondrial respiratory pathways of Candida albicans (C. albicans) on the biofilm formation. The 2, 3-bis (2-methoxy- 4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay was used to measure the metabolic activities of biofilms formed by the C. albicans which were cultured in the presence of respiratory pathways inhibitors. The biofilms formed by the wide type (WT), GOA7-deleted (GOA31), GOAV-reconstituted (GOA32), AOXla-deleted (AOX1) and AOXlb-deleted (AOX2) C. albicans strains were examined by the XTT reduction assay and fluorescence microscopy. The expression of adhesion-related genes BCR1, ALS1, ALS3, ECE1 and HWP1 in the biofilms formed by the above five C. albicans strains was detected by real time polymerase chain reaction. It was found that the metabolic activity of biofilms formed by C. albicans was decreased in the presence of alternative oxidase inhibitor whereas it was increased in the presence of classical mitochondrial respiratory pathway complex HI or complex IV inhibitor. AOX1 strain produced scarce biofilms interspersed with few hyphal filaments. Moreover, no significant changes in the expression of BCR1 and ALS3 were observed in the AOX1 strain, but the expression of ALSI and ECE1 was down-regulated, and that of HWP1 was up-regulated. These results indicate that both AOX1 and AOX2 can promote the biofilm formation. However, AOXla primarily plays a regulatory role in biofilm formation in the absence of inducers where the promoting effect is mainly achieved by promoting mycelial formation.
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PMID:Alternative Oxidase Promotes Biofilm Formation of Candida albicans. 3007 10