Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The neurotoxic effects of lead are controlled by a number of nutritional, physiological and environmental factors. One such factor, ethanol, might affect the neurotoxicity of lead by regulating its absorption and distribution. However, there is little information regarding the possible biochemical mechanism by which ethanol might be affecting the state of neuronal functions in lead-exposed individuals. Therefore, the present investigation involved the effect of alcohol (3 g/kg body weight, intragastrically, for 8 weeks) on lead-induced (50 mg/kg body weight, intragastrically, for 8 weeks) mitochondrial dysfunction in adult rat brain. Ethanol was found to enhance the toxic effects of lead in terms of decreased cellular energy reserves (ATP levels). Co-exposure to lead and ethanol caused marked decline in the rate of mitochondrial respiration as compared to lead alone. Further the activities of various components of the electron transport chain, viz. NADH dehydrogenase, succinate dehydrogenase and cytochrome oxidase depicted a significant decrease in the lead and ethanol co-exposed rats as compared to the lead-treated group. The results of the present study reflect that ethanol makes adult rat brain more vulnerable to the neurotoxic effects of lead in terms of altered mitochondrial energy metabolism.
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PMID:Impaired energy metabolism after co-exposure to lead and ethanol. 1591 Apr 12

The present study investigated the hypothalamic gene expressions regulated by glucocorticoids (GC), key hormones in energy homeostasis. Using the serial analysis of gene expression (SAGE) method, we studied the effects of adrenalectomy (ADX) and GC on the transcriptomes of mouse hypothalamus. Approximately 180,000 SAGE tags, which correspond to 50,000 tag species, were isolated from each group of intact or adrenalectomized mice as well as 1, 3, and 24 h after GC injection. ADX upregulated diazepam binding inhibitor gene expression while downregulating vomeronasal 1 receptor D4, genes involved in mitochondrial phosphorylation (cytochrome-c oxidase 1 and NADH dehydrogenase 3), 3beta-hydroxysteroid dehydrogenase-1, and prostaglandin D2 synthase. GC increased the gene expression levels of dehydrogenase/reductase member 3, prostaglandin D2 synthase, solute carrier family 4 member 4, and five cytoskeletal proteins including myosin light chain phosphorylatable fast and troponin C2 fast. On the other hand, GC reduced the mRNA levels of calmodulin 1 and expressed sequence tag similar to calmodulin 2, ATP synthase F0 subunit 6, and solute carrier family 4 member 3. Moreover, 7 uncharacterized and 43 novel transcripts were modulated by ADX and GC. The present study has identified genes that may regulate hypothalamic systems governing energy balance in response to ADX and GC.
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PMID:Regulation of hypothalamic gene expression by glucocorticoid: implications for energy homeostasis. 1636 73

Results of previous studies suggested a role of mitochondria in intracellular and cell-cell lactate shuttles. Therefore, by using a rat-derived L6 skeletal muscle cell line and confocal laser-scanning microscopy (CLSM), we examined the cellular locations of mitochondria, lactate dehydrogenase (LDH), the lactate-pyruvate transporter MCT1, and CD147, a purported chaperone protein for MCT1. CLSM showed that LDH, MCT1, and CD147 are colocalized with the mitochondrial reticulum. Western blots showed that cytochrome oxidase (COX), NADH dehydrogenase, LDH, MCT1, and CD147 are abundant in mitochondrial fractions of L6 cells. Interactions among COX, MCT1, and CD147 in mitochondria were confirmed by immunoblotting after immunoprecipitation. These findings support the presence of a mitochondrial lactate oxidation complex associated with the COX end of the electron transport chain that might explain the oxidative catabolism of lactate and, hence, mechanism of the intracellular lactate shuttle.
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PMID:Colocalization of MCT1, CD147, and LDH in mitochondrial inner membrane of L6 muscle cells: evidence of a mitochondrial lactate oxidation complex. 1643 51

Cyanobacteria have versatile electron transfer pathways and many of the proteins involved are functional in both respiratory and photosynthetic electron transport. Examples of such proteins include the cytochrome b (6) f complex, NADH dehydrogenase and cytochrome oxidase complexes. In this study we have cloned and sequenced two gene clusters from the marine cyanobacterium Synechococcus sp. PCC 7002 that potentially encode heme-copper cytochrome oxidases. The ctaCIDIEI and ctaCIIDIIEII gene clusters are most similar to two related gene clusters found in the freshwater cyanobacterial strain Synechocystis sp. PCC 6803. Unlike Synechocystis sp. PCC 6803, Synechococcus sp. PCC 7002 does not have a cydAB-like gene cluster which encodes a quinol oxidase. The ctaCIDIEI and ctaCIIDIIEII gene clusters were transcribed polycistronically, although the levels of transcripts for the ctaCIIDIIEII gene cluster were lower than those of the ctaCIDIEI gene cluster. The ctaDI and ctaDII coding sequences were interrupted by interposon mutagenesis and full segregants were isolated and characterized for both single and double mutants. Growth rates, chlorophyll and carotenoid contents, oxygen consumption and oxygen evolution were examined in the wild type and mutant strains. Differences between the wild type and mutant strains observed in 77 K fluorescence spectra and in pulse-amplified modulated (PAM) fluorescence studies suggest that the cyanobacterial oxidases play a role in photoinhibition and high light tolerance in Synechococcus sp. PCC 7002.
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PMID:Characterization of two cytochrome oxidase operons in the marine cyanobacterium Synechococcus sp. PCC 7002: inactivation of ctaDI affects the PS I:PS II ratio. 1643 83

Conidia of Verticillium albo-atrum Reinke and Berthold, collected from shake cultures grown in Czapek broth, were sonified for 4 or 8 minutes or ground frozen in a mortar to obtain cell-free homogenates. These were assayed for certain enzymes associated with respiratory pathways. Malic dehydrogenase was the most active, glucose-6-P and NADH dehydrogenase were less active, NADH-cytochrome c reductase, NADPH dehydrogenase, and cytochrome oxidase were low in activity, and succinic dehydrogenase and succinic cytochrome c reductase were very low to negligible in activity. No NADH oxidase activity was detected.With the exception of NADH-cytochrome c reductase and possibly succinic dehydrogenase and cytochrome c reductase, there was no evident increase in specific activity of the enzymes during germination. Some NADH-cytochrome c reductase and a small amount of succinic-dehydrogenase and cytochrome c reductase were associated with the particulate fraction from 105,000 x g centrifugation. The other enzymes, including cytochrome oxidase, almost completely remained in the supernatant fraction.Menadione and vitamin K-S(II) markedly stimulated NADH-cytochrome c reductase activity in the supernatant fraction but had much less effect on NADPH-cytochrome c reductase in this fraction or on either of these enzyme systems in the particulate fraction. Electron transport inhibitors affected particulate NADH- and NADPH-cytochrome c reductase activity but had no effect on these in the supernatant fraction.
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PMID:Relative Activities and Characteristics of Some Oxidative Respiratory Enzymes from Conidia of Verticillium albo-atrum. 1665 81

Mitochondria isolated from mesophyll protoplasts differed from mitochondria isolated directly from leaves of Avena sativa in that protoplast mitochondria (a) had a lower overall respiratory capacity, (b) were less able to use low concentrations of exogenous NADH, (c) did not respond rapidly or strongly to added NAD, (d) appeared to accumulate more oxaloacetate, and (e) oxidized both succinate and tetramethyl-p-phenylene-diamine (an electron donor for cytochrome oxidase) more slowly than did leaf mitochondria. It is concluded that cytochrome oxidase activity was inhibited, the external NADH dehydrogenase had a reduced affinity for NADH, succinate oxidation was inhibited, NAD and oxaloacetate porters were probably inhibited, and accessibility to respiratory paths may have been reduced in protoplast mitochondria. The results also suggest that there was a reduced affinity of a succinate porter for this substrate in oat mitochondria. In addition, all oat mitochondria required salicylhydroxamic acid (SHAM) as well as cyanide to block malate and succinate oxidation. Malate oxidation that did not appear to saturate the cytochrome pathway was sensitive to SHAM in the absence of cyanide, suggesting that the oat mitochondria studied had concomitant alternative and subsaturating cytochrome oxidase pathway activity.
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PMID:Respiration of Mitochondria Isolated from Leaves and Protoplasts of Avena sativa. 1666 11

At least 0.08% of the Apis mellifera nuclear genome contains sequences that originated from mitochondria. These nuclear copies of mitochondrial sequences (numts) are scattered all over the honeybee chromosomes and have originated by multiple independent insertions of mitochondrial DNA (mtDNA) as evident by phylogenetic analysis. Apart from original insertions, moderate duplications of numts also contributed to the present pattern and distribution of mitochondrial sequences in honeybee chromosomes. Assimilation of mitochondrial genes in the nuclear genome is mediated by extensive fragmentations of the original inserts. Replication slippage seems to be a major mechanism by which small sequences are inserted or deleted from mtDNA destined to nucleus. Most of the honeybee numts (84%) are located in the nongenic regions. The majority (94%) of the numts that are located in predicted nuclear genes have originated from mitochondrial genes coding for cytochrome oxidase and NADH dehydrogenase subunits. On the other hand, the mitochondrial rRNA or tRNA gene sequences are predominantly (88%) located in nongenic regions of the genome. Evidences also support for exertion of purifying selection on numts located in specific genes. Comparative analysis of numts of European, African, and Africanized honeybees suggests that numt evolution in A. mellifera is probably not demarked by speciation time frame but may be a continuous and dynamic process.
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PMID:Analysis of nuclear copies of mitochondrial sequences in honeybee (Apis mellifera) genome. 1740 97

Anaeromyxobacter dehalogenans strain 2CP-C is a versaphilic delta-Proteobacterium distributed throughout many diverse soil and sediment environments. 16S rRNA gene phylogenetic analysis groups A. dehalogenans together with the myxobacteria, which have distinguishing characteristics including strictly aerobic metabolism, sporulation, fruiting body formation, and surface motility. Analysis of the 5.01 Mb strain 2CP-C genome substantiated that this organism is a myxobacterium but shares genotypic traits with the anaerobic majority of the delta-Proteobacteria (i.e., the Desulfuromonadales). Reflective of its respiratory versatility, strain 2CP-C possesses 68 genes coding for putative c-type cytochromes, including one gene with 40 heme binding motifs. Consistent with its relatedness to the myxobacteria, surface motility was observed in strain 2CP-C and multiple types of motility genes are present, including 28 genes for gliding, adventurous (A-) motility and 17 genes for type IV pilus-based motility (i.e., social (S-) motility) that all have homologs in Myxococcus xanthus. Although A. dehalogenans shares many metabolic traits with the anaerobic majority of the delta-Proteobacteria, strain 2CP-C grows under microaerophilic conditions and possesses detoxification systems for reactive oxygen species. Accordingly, two gene clusters coding for NADH dehydrogenase subunits and two cytochrome oxidase gene clusters in strain 2CP-C are similar to those in M. xanthus. Remarkably, strain 2CP-C possesses a third NADH dehydrogenase gene cluster and a cytochrome cbb(3) oxidase gene cluster, apparently acquired through ancient horizontal gene transfer from a strictly anaerobic green sulfur bacterium. The mosaic nature of the A. dehalogenans strain 2CP-C genome suggests that the metabolically versatile, anaerobic members of the delta-Proteobacteria may have descended from aerobic ancestors with complex lifestyles.
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PMID:The mosaic genome of Anaeromyxobacter dehalogenans strain 2CP-C suggests an aerobic common ancestor to the delta-proteobacteria. 1846 Nov 35

In Yarrowia lipolytica, mitochondria contain a branched respiratory chain constituted by the classic complexes I, II, III and IV, plus an alternative external NADH dehydrogenase (NDH2e) and an alternative oxidase (AOX). The alternative enzymes are peripheral, single-subunit oxido-reductases that do not pump protons. Thus, the oxidation of NADH via NDH2e-ubiquinone-AOX would not contribute to the proton-motive force. The futile oxidation of NADH may be prevented if either NDH2e or AOX bind to the classic complexes, channelling electrons. By oxymetry, it was observed that the electrons from complex I reached both cytochrome oxidase and AOX. In contrast, NDH2e-derived electrons were specifically channelled/directed to the cytochrome complexes. In addition, the presence of respiratory supercomplexes plus the interaction of NDH2e with these complexes was evaluated using blue native PAGE, clear native PAGE, in-gel activities, immunoblotting, mass spectrometry, and N-terminal sequencing. NDH2e (but not the redirected matrix NDH2i from a mutant strain, Deltanubm) was detected in association with the cytochromic pathway; this interaction seems to be strong, as it was not disrupted by laurylmaltoside. The association of NDH2e to complex IV was also suggested when both enzymes coeluted from an ion exchange chromatography column. In Y. lipolytica mitochondria the cytochrome complexes probably associate into supercomplexes; those were assigned as follows: I-III(2), I-IV, I-III(2)-IV(4), III(2)-IV, III(2)-IV(2), IV(2) and V(2). The molecular masses of all the complexes and putative supercomplexes detected in Y. lipolytica were estimated by comparison with the bovine mitochondrial complexes. To our knowledge, this is the first evidence of supercomplex formation in Y. lipolytica mitochondria and also, the first description of a specific association between an alternative NADH dehydrogenase and the classic cytochrome pathway.
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PMID:In Yarrowia lipolytica mitochondria, the alternative NADH dehydrogenase interacts specifically with the cytochrome complexes of the classic respiratory pathway. 1903 29

Acute exposure to organophosphates induces a delayed neurodegenerative condition known as organophosphate-induced delayed neuropathy (OPIDN). The mechanism of OPIDN has not been fully understood as it does not involve cholinergic crisis. The present study has been designed to evaluate the role of mitochondrial dysfunctions in the development of OPIDN. OPIDN was induced in rats by administering acute dose of monocrotophos (MCP, 20 mg/kg body weight, orally) or dichlorvos (DDVP, 200 mg/kg body weight, subcutaneously), 15-20 min after treatment with antidotes [atropine (20 mg/kg body weight) and 2-PAM (100 mg/kg body weight) intraperitoneally]. MDA levels were observed to be higher and thiol content was lower in mitochondria from brain regions of OP exposed animals. This was accompanied by decreased activities of the mitochondrial enzymes; NADH dehydrogenase, succinate dehydrogenase, and cytochrome oxidase. In addition, mitochondrial functions assessed by MTT reduction also confirmed mitochondrial dysfunctions following development of OPIDN. The spatial long-term memory evaluated using elevated plus-maze test was observed to be deficit in OPIDN. The results suggest impaired mitochondrial functions as a mechanism involved in the development of organophosphate induced delayed neuropathy.
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PMID:Impaired mitochondrial functions in organophosphate induced delayed neuropathy in rats. 1951 27


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