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PubMed1992

Mitochondrial DNA sequence analysis of the cytochrome oxidase subunit I and II genes, the ATPase9 gene, the NADH dehydrogenase ND4L and ND5 gene complex, and the glutaminyl, methionyl and arginyl tRNA genes from Trichophyton rubrum.

In this paper, we present the nucleotide sequence of a 5248 bp-long region of the mitochondrial (mt) genome of the dermatophyte Trichophyton rubrum. This region which represents about 1/4 of the total mt genome of this species reveals a compact organization of genes including: the glutaminyl tRNA, the methionyl tRNA, the cytochrome oxidase subunit I gene, the arginyl tRNA, the mitochondrial version of the ATPase subunit 9 gene, the cytochrome oxidase subunit II gene and a part of the NADH dehydrogenase ND4L and ND5 gene "complex". The main features of the part of mt DNA sequenced is the non-interrupted COXI gene and the presence in the mitochondrial version of the ATPase 9 gene of a small group IA intron. The extensive amino-acid sequence similarity with the equivalent gene in Aspergillus nidulans and Neuropora crassa indicates that this gene codes for a dicyclohexylcarbodiimide binding protein. The conserved arrangement of this portion of the mt genome and the presence of tRNAs between the protein-coding genes are compatible with a large polycistronic transcript processed by the excision of tRNAs, or similar secondary structures, as proposed for other fungal or mammalian mt DNAS.

Adenosine Triphosphatases↗
PubMed1998

Optical characterization of heme a + a3 and copper of cytochrome oxidase in blood-free perfused rat brain.

For the precise examination of the optical characteristics of cerebral tissue, we prepared hemoglobin-free perfused rat heads, from which trace amounts of blood were completely removed. In this preparation at 30 degrees C, the redox responses of the cytochrome oxidase components, heme a + a3 and copper, were followed spectrophotometrically in visible and near-infrared regions, and were correlated with the changes in neural activity as monitored by electroencephalography (EEG). During the aerobic-anaerobic transition, there was clear dissociation of the time courses of the reduction of heme a + a3 and copper; the reduction of heme a + a3 preceded the reduction of copper. The EEG activity decreased earlier than the reduction of heme a + a3. Pentylenetetrazole administration in normoxia caused the partial reduction of heme a + a3 but not of copper. The redox behaviors of cytochrome oxidase components in the brain were identical to those observed in isolated mitochondria. The usefulness of brain preparation for bridging the in vivo and in vitro studies is documented where various circulatory parameters could be controlled artificially.

Aerobiosis↗
PubMed1986

Localization of cytochrome oxidase in the mammalian spinal cord and dorsal root ganglia, with quantitative analysis of ventral horn cells in monkeys.

The spinal cord and dorsal root ganglia of mice, rats, cats, squirrel monkeys, and macaque monkeys were examined at both the light and electron microscopic levels for cytochrome oxidase activity. A similar histochemical pattern prevailed in all of the species examined. While the spinal gray exhibited a heterogeneous but consistent distribution of the enzyme, the white matter was only lightly stained. Highly reactive neurons were either singly scattered or aggregated into discrete clusters. The dorsal nucleus of Clarke, the lateral cervical nucleus (cat), the intermediolateral cell columns of the thoracic and upper lumbar levels, and selected groups of ventral horn neurons formed moderate to darkly reactive cell clusters, whereas fusiform and multipolar cells of Waldeyer in the marginal layer, small fusiform neurons in the ventral gray, funicular cells in the white matter, and ventral horn neurons of varying sizes tended to stand out against the neuropil as singly reactive neurons. At the electron microscopic level, reactive neurons were characterized by a greater packing density of darkly reactive mitochondria, while lightly reactive ones had fewer mitochondria, most of which showed very little reaction product. Reactive mitochondria were also found in the neuropil, mainly in dendritic profiles and some axon terminals. Glial cells, in general, were not very reactive. Ventral horn neurons from three macaque monkeys were measured for somatic areas and optical densities of cytochrome oxidase reaction product. A total of 1,770 neurons from representative sections of the cervical, thoracic, lumbar, and sacral cords of these animals were analyzed. The results indicated that the distribution of cell sizes as well as optical densities at every level of the cord fell on a continuum. Analysis of the regression coefficients revealed that the slopes were negative for all levels, indicating that there was a general inverse relationship between cell size and optical densities. However, there were representations of dark, moderate, and lightly reactive neurons in all three size categories (large, medium, and small). Thus, the level of oxidative metabolism of ventral horn neurons cannot be correlated strictly with size, but it is likely to reflect their total synaptic and spontaneous activities. Neurons of the dorsal root ganglia likewise exhibited heterogeneous distribution of cell sizes and levels of enzyme reactivity, while satellite cells, in general, were only lightly reactive. As in the case of the ventral horn, representatives of dark, moderate, and light levels of reactivity occurred in every size category of neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Cytochrome oxidase staining in the rat SmI barrel cortex.

Patterns of cytochrome oxidase (CO) activity were examined histochemically in the rat SmI cortex. Discrete regions of high enzymatic activity were centered upon the granule cell aggregates (barrels) in layer IV. Those barrels which correspond to the mystacial vibrissae and make up the posteromedial barrel subfield (PMBSF) were especially interesting in that CO staining revealed distinct metabolic subdivisions which do not have an easily demonstrable cytoarchitectonic counterpart. By analogy with the barrels in mouse PMBSF and with the cytoarchitectonically distinct barrels representing the smaller sinus hairs in the rat we propose that regions of high CO activity denote the "hollow" of the rat PMBSF barrels. In accord with previous physiological studies demonstrating a vertical organization in the rodent barrel cortex, we also noted columns of intense CO activity extending from layer VI through sublamina Vb. The centers of these columns coincided with the centers of the barrels in layer IV. In tangential sections through the infragranular laminae the segmentation of CO-positive zones was less distinct than in layer IV and appeared as bands of heightened activity oriented like the five rows of layer IV barrels. Highly reactive somata and dendrites were observed in both the granular and infragranular CO barrels indicating that some of the increased activity of these regions reflects oxidative metabolism of cortical neurons per se. These patterns of metabolic activity underscore the vertical and horizontal organization of the SmI vibrissa cortex and suggest that neurons located within the central core of a column have functional properties distinct from those located in zones where individual columns interface.

Animals↗
PubMed1986

Differential effect of visual deprivation on cytochrome oxidase levels in major cell classes of the cat LGN.

Cytochrome oxidase histochemistry was used to examine the effects of visual deprivation on the development of neurons in the lateral geniculate nucleus of the kitten. Early postnatal monocular suture results in a decrease in reactivity within the neuropil of visually deprived binocular laminae A, A1, magnocellular C, and medial interlaminar nucleus. Within these regions, monocular suture has a greater effect on the relative numbers of, and the growth of darkly reactive (normally large), presumed Y-cells than on other less reactive geniculate neuronal classes. The decreases in the reactivity of the neuropil may be attributed to the decreases in the number of mitochondria, the number of darkly reactive mitochondria, and/or the number of darkly reactive mitochondria localized within dendrites. Although all classes of dendrites appear to be adversely affected, the decrease in C.O. reactivity was most dramatic within the presumed proximal dendrites of class 1 Y-cells. These dendrites were identified by the type of synaptic contacts they formed with retinal terminals (Rapisardi and Miles, '84, J. Comp. Neurol. 223:515-534; Wilson et al., '84, Proc. R. Soc. Lond. [Biol.] 221:411-436). As with Y-cells, the effects of monocular suture on the large darkly reactive cells were not as dramatic at sites where binocular interactions were either absent or where they had been experimentally eliminated. Based on the present and previously reported findings from several laboratories, it is likely that the selective physiological and morphological effects of monocular suture on Y-cells are accompanied by metabolic deficits involving both dendrites and perikarya. These effects appear to be due more to binocular interactions than to visual deprivation per se.

Animals↗
PubMed1986

Histochemical demonstration of vibrissae-representing patchy patterns of cytochrome oxidase activity within the trigeminal sensory nuclei in the cat.

Cytochrome oxidase histochemistry revealed patchy patterns of the enzyme activity in transverse sections through the caudal part of the ventral subnucleus of the principal sensory trigeminal nucleus, interpolar spinal trigeminal nucleus, and layer IV of the caudal spinal trigeminal nucleus in the cat. By the transganglionic transport method of horseradish peroxidase, the patterns were indicated to replicate the spatial array of the facial vibrissae.

Animals↗
PubMed1983

Changes induced by hydrazine in optical spectra of cytochrome oxidase.

Under aerobic conditions hydrazine reduces haem a of cardiac cytochrome oxidase and brings about the formation in optical spectra of a new band at 845 nm, whereas under anaerobic conditions hydrazine reduces both haems, a and a3, as well as EPR-detectable copper, CuA, and results in the band at 845 nm. The formation of this band was sensitive to inhibitors of oxygen binding. It is suggested that the band at 845 nm reflects changes induced by hydrazine in CuB which in the resting enzyme is EPR-undetectable.

Animals↗
PubMed1991

The assignment of the 655 nm spectral band of cytochrome oxidase.

The spectral characteristics of the '655 nm' band of cytochrome oxidase were found to be affected by ligands of the binuclear centre, including formate and chloride, and by the resting/pulsed transition. The band titrated with near n = 1 characteristics at a midpoint of about 400 mV, in contrast to haem a3, which exhibits strong redox interaction and a titration range at significantly lower potential. Thus, although the total reduced-oxidised difference spectrum of haem a3 shows a trough at about 655 nm, this characteristic is absent in the low potential region. The 655 nm feature may arise from a charge transfer band of ferric high-spin haem a3, which is modulated by the redox state of CuB, as suggested by Beinert et al. [(1976) Biochim. Biophys. Acta 423, 339-355].

Animals↗
PubMed2000

Daily changes of cytochrome oxidase activity within the suprachiasmatic nucleus of the Syrian hamster.

Cytochrome oxidase (CO) activity was studied over a 24-h period in the Syrian hamster suprachiasmatic nucleus (SCN) (site of the biological clock), anterior hypothalamic area (AHA), and motor cortex. The SCN CO activity was highest at the middle of the day (Zeitgeber time (ZT) 05), decreased at the end of the light period (ZT 10) and continued at a low level during the night (ZT 13, 16, 21.5 and 24). AHA and motor cortex showed a similar profile of CO activity and no changes of CO activity were found in animals maintained under darkness (DD). We propose that photic input plays a role in the SCN neuronal activity that modulates metabolic activity on this area.

Animals↗
PubMedDate not supplied

Effect of early monocular enucleation upon ocular dominance columns and cytochrome oxidase activity in monkey and human visual cortex.

We examined cytochrome oxidase (CO) activity in striate cortex of four macaque monkeys after monocular enucleation at ages 1, 1, 5, and 12 weeks. These animal experiments were performed to guide our interpretation of CO patterns in occipital lobe specimens obtained from two children who died several years after monocular enucleation during infancy for tumor. In the macaques, the ocular dominance columns were labelled by injecting [3H]proline into the remaining eye. After enucleation at age 1 week, ocular dominance columns were eliminated in layer IVc(beta), resulting in a uniform pattern of autoradiographic label and CO staining. However, columns could still be seen in wet, unstained sections and with the Liesegang silver stain. Autoradiographs through layers IVc(alpha) and IVa showed residual, shrunken columns belonging to the missing eye, indicating that enucleation has less drastic effects in these layers. In the two human cases, enucleation at age 1 week also resulted in uniform CO staining in layer IVc. In the macaque after enucleation at age 5 weeks, ocular dominance columns belonging to the missing eye were severely narrowed, but still occupied 20% of layer IVc(beta). CO revealed wide, dark columns alternating with thin, pale columns in layer IVc(beta). The CO pattern and the columns labelled by autoradiography matched perfectly. After enucleation at age 12 weeks, only mild shrinkage of ocular dominance columns occurred. Enucleation at ages 1, 5, and 12 weeks did not alter the pattern of thin-pale-thick-pale stripes in V2. The main findings from this study were that (1) CO histochemistry accurately labels the boundaries of columns in layer IVc(beta) of macaque striate cortex after early monocular enucleation, making it a suitable technique for defining the critical period for plasticity of ocular dominance columns in human striate cortex; (2) enucleation causes more severe shrinkage of ocular dominance columns than eyelid suture; (3) early monocular enucleation obliterates ocular dominance columns in layer IVcbeta, but their pattern remains visible in wet sections and with the Liesegang stain; and (4) enucleation does not affect CO staining in V2.

Animals↗
PubMed1993

Relationships in the Drosophila obscura species group, inferred from mitochondrial cytochrome oxidase II sequences.

We compare the sequences for the mitochondrial cytochrome oxidase II gene of 13 species of the Drosophila obscura group. The survey includes six members of the D. affinis subgroup, four of the D. pseudoobscura subgroup, and three of the D. obscura subgroup. In all species, the gene is 688 nucleotides in length, encoding a protein of 229 amino acids plus the first position T of the stop codon. The sequences show the typical high-transition bias for closely related species, but that bias is essentially eliminated for species pairs of > 5% sequence divergence. The phylogenetic relationships in the species group are inferred using both neighbor-joining and maximum parsimony. The two procedures give comparable results, showing that the D. affinis and D. pseudoobscura subgroups are monophyletic groupings that appear to have closer affinities to one another than either has to the D. obscura subgroup. We use transversion distances to estimate times of divergence, on the basis of three different estimates of the time of separation of the D. obscura species group from the D. melanogaster group. If that event occurred 35 Mya, then we can estimate the origin of the nearctic forms at approximately 22 Mya and the separation of the D. affinis and D. pseudoobscura subgroups at approximately 17 Mya.

Animals↗
PubMed1988

Spectrophotometric characterization of intermediate redox states of cytochrome oxidase.

The spectrophotometric characteristics of hemes a and a3 in cytochrome oxidase have been examined over the range 380 nm to 900 nm. Difference spectra (relative to the oxidized form) are presented for ferrous, high-spin oxidized, low-spin oxidized, early "pulsed," late "pulsed," and two-peroxide-treated states of the enzyme. Comparisons indicate that the decay product of the initial peroxide complex of the enzyme is identical to a low-spin pulsed form of the enzyme. A high-spin pulsed form of the enzyme persists for several hours to days after preparation.

Cyanides↗
PubMed1988

Ultrastructural analysis of cytochrome oxidase in chick epiphyseal growth plate cartilage.

Histochemical detection of cytochrome oxidase activity in chicken growth plate revealed both positively and negatively stained mitochondria in chondrocytes of all zones, i.e., proliferative, pre-hypertrophic, hypertrophic, and calcifying zones. The proportion of positive to negative cells was lowest in the proliferative zone. As cytodifferentiation progressed, more positively stained cells were present. In positive cells all mitochondria were usually stained, and in negative cells all mitochondria were unstained. A few cells appeared to be in transition and contained both types of mitochondria. The results indicate that chondrocytes utilizing both aerobic and anaerobic metabolism are present in growth plate cartilage and that oxidative metabolism is favored in the more mature cells. The relationship of oxidative metabolism to calcification is discussed.

Animals↗
PubMed1984

[Detection of Pseudomonas cytochrome oxidase and esterase in blood culture broths].

Search for cytochrome-oxidase was performed directly on blood culture broths without prior isolation of the pathogen on agar, using paper disks impregnated with "oxidase" reagent and the Api Z strip which enables additional detection of esterases. Both these tests are indicative of the presence of Pseudomonas. False-positive results were recorded in only 0.65% of the 167 strains of Enterobacteria studies. The 38 strains of Pseudomonas aeruginosa gave 5.26% false-negative results; 88.6% of Pseudomonas strains were esterase-positive. Simultaneous search for both these enzymes thus allows for identification and antibiotic sensitivity testing before agar isolation.

Blood↗
PubMed2006

Changes in the neuronal activity in the pedunculopontine nucleus in chronic MPTP-treated primates: an in situ hybridization study of cytochrome oxidase subunit I, choline acetyl transferase and substance P mRNA expression.

The pedunculopontine nucleus is a mesencephalic nucleus that has widespread and reciprocal connections with the basal ganglia. It has been implicated in the physiopathology of akinesia, rigidity, gait failure and sleep disorders associated with Parkinson's disease. In this study, in situ hybridization was used to examine the changes in neuronal metabolic activity (measuring cytochrome oxidase subunit I) and in the level of acetylcholine and Substance P synthesis in the pedunculopontine nucleus of monkeys chronically treated with MPTP. Significant reductions were observed in cytochrome oxidase subunit I (p = 0.001), choline acetyl transferase (p = 0.003) and substance P (p = 0.006) mRNA expression in parkinsonian animals compared with controls, indicating that pedunculopontine cholinergic neurons activity decreases with parkinsonism.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1988

Molecular defects in cytochrome oxidase in mitochondrial diseases.

Defects of cytochrome c oxidase (COX) show remarkable clinical, biochemical, and genetic heterogeneity. Clinically, there are two main groups of disorders, one dominated by muscle involvement, the other by brain dysfunction. Biochemically, the enzyme defect may be confined to one or a few tissues (reflecting the existence of tissue-specific isozymes) or affect all tissues. Immunologically reactive enzyme protein is decreased in some forms of COX deficiency but not in others. Because COX is encoded both by nuclear and by mitochondrial genes, COX deficiencies may be due to mutations of either genome and may offer useful models to study the communication between nuclei and mitochondria. We have isolated full-length cDNA clones encoding human COX subunits IV, Vb, and VIII and a partial-length clone for subunit Va. These clones are being used as probes to analyze the DNA and RNA of patients with COX deficiency.

Brain Diseases↗
PubMed2000

Cytochrome oxidase immunohistochemistry: clues for genetic mechanisms.

Cytochrome c oxidase (COX) is encoded by three mitochondrial and nine nuclear genes. COX deficiency is genetically heterogeneous but current diagnostic methods cannot easily distinguish between mitochondrial and nuclear defects. We hypothesized that there may be differential expression of COX subunits depending on the underlying mutation. COX subunit expression was investigated in five patients with known mtDNA mutations. Severe and selective reduction of mtDNA-encoded COX subunits I and II was consistently observed in all these patients and was restricted to COX-deficient fibres. Immunostaining of nuclear-encoded subunits COX IV and Va was normal, whilst subunit VIc, also nuclear-encoded, was decreased. Twelve of 36 additional patients with histochemically defined COX deficiency also had this pattern of staining, suggesting that they had mtDNA defects. Clinical features in this group were heterogeneous, including infantile encephalopathy, multisystem disease, cardiomyopathy and childhood-onset isolated myopathy. The remaining patients did not have the same pattern of immunostaining. Fourteen had reduced staining of all subunits, whilst 10 had normal staining of all subunits despite reduced enzyme activity. Patients with COX deficiency secondary to mtDNA mutations have a specific pattern of subunit loss, but the majority of children with COX deficiency do not have this pattern of subunit loss and are likely to have nuclear gene defects.

Adolescent↗
PubMed1994

Genes of the linear mitochondrial DNA of Williopsis mrakii: coding sequences for a maturase-like protein, a ribosomal protein VAR1 homologue, cytochrome oxidase subunit 2 and methionyl tRNA.

The mitochondrial DNA (mtDNA) in some yeasts has a linear structure with inverted terminal repeats closed by a single-stranded loop. These mtDNAs have generally a constant gene order, beginning with a small ribosomal RNA gene at the right end and terminating with a cytochrome oxidase subunit 2 gene (COX2) at the left end, independently of the wide variation in genome size. In the mtDNAs from several species of the genus Williopsis, we found an additional open reading frame, ORF1, which was homologous to the Saccharomyces cerevisiae RF1 gene encoding a group I intron maturase-like protein. ORF1 genes from W. mrakii and W. suaveolens were mapped and sequenced. Next to ORF1, COX2 and methionyl tRNA genes were present on the opposite strand. The same relative positions of genes in the mtDNAs so far examined suggests that the constancy of gene order is generally conserved also at the level of individual tRNA genes. We identified another open reading frame, ORF2, in W. mrakii mtDNA. It was mapped next to the cytochrome oxidase subunit 3 gene. Rich in adenine-thymine bases, ORF2 appears to be a homologue of the VAR1 gene which codes for a small ribosomal subunit protein in S. cerevisiae mitochondria. Nucleotide sequences data have been deposited in the EmBL data library under the following Accession Numbers: X66594 (Apocytochrome b and ORF2 genes of W. mrakii), X66595 (ORF1, tRNA-Met and COX2 genes of W. mrakii), X73415 (tRNA-Met and COX2 genes of W. suaveolens), X73416 (ORF1 gene of W. suaveolens) and X73414 (tRNA-Met and COX2 genes of P. jadinii).

Amino Acid Sequence↗