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)

To study the effects of deep freezing on the energy metabolism of human spermatozoa, we investigated, by cytochemical quantitative methods, cytochrome oxidase and lactate dehydrogenase activities of fresh and frozen human spermatozoa during in vitro capacitation. Fresh and frozen human spermatozoa were incubated in Biggers, Whitten and Wittingham's medium supplemented with 15% heat-inactivated human serum. Both histoenzymological reactions can be quantitated and have been evaluated by microdensitometric method. The results indicate that human spermatozoa depend almost entirely on anaerobic glycolysis during in vitro capacitation and suggest that both aerobic and anaerobic metabolism in spermatozoa are only slightly impaired by freezing-thawing and storage.
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PMID:[Cytochemical study of human sperm metabolism during in vitro capacitation after cryopreservation]. 132 25

Human spermatozoa contain appreciable amounts of intracellular glutathione, which has a protective function against peroxidative degradation of spermatozoal polyunsaturated fatty acids by the NADPH-dependent glutathione peroxidase/reductase enzymatic system. The glutathione system provides a basic defense against peroxidative damage, without which the superoxide dismutase system would dominate. Since oxidative damage is said to include enzyme leakage and changes in metabolism, cytochrome oxidase and lactate dehydrogenase activities were used as indicators of the energy metabolism in unwashed and washed human spermatozoa during lipid peroxidation. Lipid peroxidation was induced by aerobic incubation of sperms in the presence of sodium ascorbate and ferrous sulphate. In addition, since NADPH concentrations influence the concentration of reduced glutathione, we studied glucose-6-phosphate dehydrogenase activity as an indicator of pentose phosphate shunt activity, the main source of NADPH. Microdensitometric measurements of the three enzymes were made by a Vickers M85a scanning microdensitometer. We found that the lipid peroxidation process greatly affects the 3 enzymatic activities examined and that seminal plasma protects against the extensive deleterious effects of lipid peroxidation.
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PMID:Cytophotometric assay of cytochrome oxidase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activities in human peroxidized spermatozoa. 133 42

Sperm metabolism was determined via reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to formazan. When the reaction mixture contained cyanide, which blocks cytochrome oxidase and thus maximizes intermediate electron transfer to INT, and calcium which stimulates fowl sperm motility, the metabolic capacity of spermatozoa from subfertile Delaware and Wyandotte roosters was 90 and 63% of that of spermatozoa from fertile Leghorn roosters. When the assay was performed at 40 degrees C without calcium or cyanide, no difference in metabolism was observed between Delaware and Leghorn spermatozoa (P greater than 0.05). However, the metabolism of Wyandotte spermatozoa was 66% of that observed with Delaware or Leghorn spermatozoa. These results provide further evidence that heritable subfertility in Delaware and Wyandotte roosters is attributable to distinct sperm defects.
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PMID:Comparative metabolism of spermatozoa from subfertile Delaware and Wyandotte roosters. 199 43

In Eutherian (mammalian) spermatozoa, maturation and capacitation are associated to modifications of the metabolic activities. In order to demonstrate such variations, a quantitative cytochemical study was carried out on cytochrome oxidase and L-lactate dehydrogenase activities in mouse spermatozoa collected from the male and female genital tracts and at different times of the in vitro capacitation. Microdensitometric measurements were made on a Vickers M85 integrator microdensitometer at lambda = 480 +/- 5 nm and lambda = 585 +/- 5 nm wavelengths for the cytochrome oxidase and LDH activities, respectively. The cytochrome oxidase activity first decreases and then increases significantly both during maturation and during capacitation in vivo and in vitro. The LDH activity decreases significantly and gradually in the male and female genital tracts as well as in the course of in vitro capacitation where, however, an enhancement in the anaerobic glycolysis occurs.
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PMID:Microphotometric study on cytochrome oxidase and lactate dehydrogenase activities in mouse spermatozoa during maturation and in vivo and in vitro capacitation. 254 Jun 4

We report a quantitative cytochemical study on cytochrome oxidase and lactate dehydrogenase activities on rabbit epididymal spermatozoa during spontaneous lipid peroxidation. Our data show that during aerobic incubation both in NTP and KTP media the sperm cytochrome oxidase activity undergoes a significant decrease. The lactate dehydrogenase activity shows different cytochemical patterns in comparison between the two media considered. Such activity significantly increases in rabbit spermatozoa suspended in NTP medium from the first until the sixteenth hour of incubation time. At the following times the lactate dehydrogenase activity significantly declines showing yet until the later times of incubation integrated optical density values fairly high. During the whole period of the aerobic incubation, the spermatozoa suspended in medium KTP show lactate dehydrogenase integrated optical density values which not significantly differ from those of the control in spite of an initial enhancement from the first until the thirteenth hour of the experimental treatment.
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PMID:Cytochrome oxidase and lactate dehydrogenase activities in peroxidized rabbit epididymal spermatozoa. 254 15

Inheritance of the mitochondrial genome is known to be exclusively maternal. To determine whether the loss of paternal mitochondria could be due to a deficiency of RNA in the spermatozoal mitochondria, the expression of mitochondrial genes was studied in testicular cells at various stages of spermatogenesis and in epididymal spermatozoa. The presence of mitochondrial transcripts was examined by Northern blot analysis using probes for the following mitochondrially encoded genes: 12 S and 16 S ribosomal RNAs and a group of mRNAs including cytochrome oxidase subunits I and II (COI-COII), cytochrome b (cyt b), adenosine triphosphatase (ATPase) subunits 6 and 8, and subunit 1 of the respiratory chain NADH dehydrogenase (ND1). Comparison of total testicular RNA preparations from prepuberal (6, 8, 12, 16, 18, 20, 22, and 30 days old) and sexually mature (45 days old) mice revealed no major qualitative or quantitative differences in the levels of the mitochondrial transcripts described above. Similar results were observed from enriched preparations of type A and B spermatogonia and interstitial cells obtained from the testes of 8-day-old mice. Transcripts for COI-COII, ATPase 6, or ND1 were reduced in amount in the enriched preparations of pachytene spermatocytes, round spermatids, and residual bodies when compared to the amount in total testis or liver RNA. Transcripts of all the mitochondrial genes analyzed were present in RNA preparations isolated from sperm midpiece tails obtained after sonication of epididymal spermatozoa. These studies demonstrate that (a) during testicular development the levels of mitochondrial RNA in total testicular extracts show no major qualitative and quantitative differences; (b) the mitochondrial transcripts in enriched populations of type A and type B spermatogonia are not different from those obtained from total testes extracts; (c) mitochondrial transcript levels gradually decrease in enriched preparations of pachytene spermatocytes, round spermatids, and residual bodies; and (d) the mitochondrial rRNAs and mRNAs encoded by several mitochondrial genes can be isolated from sperm midpiece tails.
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PMID:Mitochondrial gene expression in male germ cells of the mouse. 277 68

In eutherian mammalian spermatozoa the capacitation is coupled to a specific type of metabolism, that is glycolysis or oxidative respiration. A cytochemical study was carried out on cytochrome oxidase and lactate dehydrogenase in human spermatozoa collected at different times during in vitro capacitation. Human spermatozoa were incubated in Biggers, Whitten and Wittingham's medium supplemented with 15% heat-inactivated human serum. Both histoenzymological reactions based on oxidative polymerization of diaminobenzidine (cytochrome oxidase) or on tetrazolium salts reduction (lactate dehydrogenase) can be quantitated and have been evaluated by microdensitometric method (Vickers M85). The results suggest that human spermatozoa depend almost quite on the anaerobic glycolysis during in vitro capacitation.
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PMID:Cytochemical study on human spermatozoa metabolism during in vitro capacitation. 282 Feb 70

Ejaculated human spermatozoa were subjected to nitrogen cavitation (600 psi for ten min) to remove the plasma membrane (PM). Electron microscopic examination of the cavitated cells revealed that 33% of the PM was removed from the sperm which includes both the head and tail regions. The released membrane was separated from the cavitated cells by centrifugation followed by a discontinuous sucrose density gradient centrifugation. A single membrane population was resolved at the 1.0 M sucrose interface. Examination of the isolated membranes by electron microscopy revealed vesicles of various sizes displaying unit membrane structures. Biochemical analysis of the isolated membranes showed a threefold enrichment in the surface membrane marker 5' nucleotidase and also suggested little contamination by enzymes from the cytosol (lactate dehydrogenase) or mitochondria (cytochrome oxidase). Analytical lipid analysis of the isolated membranes revealed a 26-fold enrichment in the distribution of cholesterol, an 11-fold enrichment of phospholipids, and a cholesterol:phospholipid molar ratio of 0.83. Also found was a twofold increase in glycosphingolipids which are ubiquitous components of PM in eukaryotic cells. These data indicate that the membrane vesicles isolated after nitrogen cavitation are primarily PM.
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PMID:Isolation and partial characterization of the plasma membrane from human spermatozoa. 302 93

Washed human spermatozoa had an endogenous oxygen uptake of 2.14 +/- 0.17 nmol O2/10(8) spermatozoa/min (mean +/- s.e..m., n = 35) which was stimulated by succinate (Vmax = 9.64 +/- 0.44 nmol O2/10(8) spermatozoa/min) but not by other substrates. The ATP concentration in freshly washed spermatozoa was 12.18 +/- 0.54 (s.e.m.) nmol/10(8) spermatozoa (n = 26) and was maintained for 2 h in the presence of 2 mM-D-glucose but fell to 9.56 +/- 0.73 (s.e.m.) nmol/10(8) spermatozoa (n = 13) in its absence. The presence of 2 microM-antimycin A, 2 microM-rotenone, 0.4 microM-carbonyl cyanide m-chlorophenyl hydrazone or 8 microM-oligomycin caused the ATP concentration to fall to less than 2 nmol/10(8) spermatozoa but their effect was partly alleviated by 2 mM-glucose. Sodium malonate (5 mM) prevented the stimulation of respiration by succinate but had no effect on the ATP concentration of the spermatozoa or their ability to produce 14CO2 from [U-14C]glucose. The least active of the tricarboxylic acid cycle enzymes was 2-oxoglutarate dehydrogenase (EC 1.2.4.2) (3.1 +/- 0.6 (s.e.m.) nmol substrate transformed/10(8) spermatozoa/h (n = 4). Cytochrome c oxidase (EC 1.9.3.1) was much less active than in rat spermatozoa (22.3 +/- 6.0 (s.e.m., n = 4) and 615 +/- 87 (n = 4) nmol transformed/10(8) spermatozoa/min). It is concluded that human spermatozoa can obtain ATP by the respiration of endogenous substrate but the substrates and metabolic pathways involved remain obscure.
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PMID:The role of oxidative phosphorylation in the generation of ATP in human spermatozoa. 727 30

It has been suggested that along the female genital tract spontaneous lipid peroxidation regulates the limit of the lifetime of spermatozoa. We have studied some aspects of rabbit and mouse spermatozoal metabolism during spontaneous lipid peroxidation in the course of the incubation in media which simulate the oviductal environment. The spermatozoa collected at regular intervals after the beginning of incubation were processed for cytochemical detection of cytochrome oxidase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activities. Quantitative cytochemical assays were made in situ in individual spermatozoa by microdensitometry. The cytochrome oxidase activity significantly decreased in both species because of damage to mitochondrial enzymes and membranes by radical and non-radical products of lipid peroxidation. The change in lactate dehydrogenase activity indicates that under our experimental conditions the lipid peroxidation process damages membrane permeability more markedly in mouse spermatozoa. The glucose-6-phosphate dehydrogenase activity, which should influence the concentration of reduced glutathione through production of NADPH, is more extensively enhanced in mouse spermatozoa than in rabbit spermatozoa. This is in agreement with the fact that in mouse spermatozoa the glutathione system is the major protective defence against oxidative damage while in rabbit spermatozoa it is superoxide dismutase.
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PMID:Spontaneous lipid peroxidation and sperm metabolism during incubation in media simulating the oviductal microenvironment. 778 44


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