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Topic:Mitochondria
Mitochondria are organelles found in the cells of horses that are responsible for producing energy through the process of oxidative phosphorylation. They play a role in various cellular functions, including energy metabolism, regulation of the cell cycle, and apoptosis. Mitochondria contain their own DNA, which is maternally inherited and can provide insights into genetic lineage and population studies in equines. Research on equine mitochondria encompasses topics such as mitochondrial function, genetic variation, and their implications for health and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and genetic aspects of mitochondria in horses.
[Functional morphology of the large intestinal mucosa of horses (Equus przewalskii f. caballus) with special regard to the epithelium]. The mucous membrane of the caecum and colon ascendens of adult horses was first studied using light and transmission electron microscopy. In the surface epithelium there was an inconspicuous constellation of organelles, otherwise there was a lot of mitochondria as a source of energy for absorptive performances. Moreover, enlarged intercellular spaces exist as an indication of an increased uptake of water and electrolytes. In the basal region of Lieberkühn's crypts there were single enteroendocrine cells and numerous granules in the apical epithelial cytoplasm. The functional meaning of these ...
Equine sarcoid tumour treated by autogenous tumour vaccine. Twenty-one horses with sarcoid tumours were treated by bio-immunotherapy using autogenous vaccines during 1991-1997. At operation the base of the tumour was left in the skin and autovaccines were made from extirpated tumour tissue by polymerization. The horses thus formed their own internal control group. One of 12 horses having a primary tumour, and four of 9 horses suffering recurrent tumours, prior to bio-immunotherapy, developed single recurrences. Four of these five horses suffering recurrence were treated anew, leading to remission. Disease-free intervals were longer for primary (P = 0.0...
Ultrastructure, protein phosphorylation and mRNA status of equine oocytes matured in vivo and in vitro. Equine oocytes were collected by follicle aspiration in vivo or by dissection of material obtained from an abattoir, and the ultrastructure, protein phosphorylation and mRNA status of the oocytes were evaluated. Electron microscopy studies indicated that the nucleus had a smooth membrane in oocytes with a compact cumulus, whereas the nuclear membrane was undulated in all other groups. Oocytes with compact cumuli had only a few microvilli, whereas those with expanded cumuli had more microvilli. There were only small numbers of cortical granules close to the oolemma in oocytes with compact cumul...
Mitochondrial D-loop sequence variation among the 16 maternal lines of the Lipizzan horse breed. Mitochondrial DNA from 49 Lipizzan horses representing 16 maternal lines from the original stud at Lipica was used for SSCP analysis and DNA sequencing. The SSCP analysis of the 444 bp long fragment of the D-loop region extending from the tRNA(Pro) gene to the central conserved sequence block revealed three distinct groups of SSCP patterns. Both ends of the D-loop region (378 bp and 310 bp), which are considered as the most variable regions within the mammalian mitochondrial DNA, were sequenced. According to 49 polymorphic sites identified within the both parts of the D-loop region, the 16 mat...
Phylogenetic relationships of Cheju horses to other horse breeds as determined by mtDNA D-loop sequence polymorphism. Historical records suggest that horses inhabiting the island of Cheju in Korea are descendants of Mongolian horses introduced in 1276. Other studies, however, suggest that horses may have been present on the island prior to the Mongolian introduction. To determine the origin of the Cheju horses we used a phylogenetic analysis of sequences of the mitochondrial DNA (mtDNA) D-loop region, including tRNA Pro and parts of tRNA thr and tRNA Phe sequences (1102-bp excluding the tandem repeat region). Maximum parsimony and neighbor-joining trees were constructed using sequences determined for seven Ch...
Streptococcus equi but not Streptococcus zooepidemicus produces potent mitogenic responses from equine peripheral blood mononuclear cells. Streptococcus equi causes equine strangles. The acute disease has many of the hallmarks of an acute response including high fever, elevated plasma fibrinogen and neutrophilia, affects known to be mediated by proinflammatory cytokines. The objective of this study was to screen-culture supernatants from equine clinical isolates of S. equi and S. zooepidemicus for stimulation of mitogenic responses by horse peripheral blood mononuclear cells. Mitogenicity comparable to that of concanavalin A was detected in culture supernatants of S. equi strains but not in those of S. zooepidemicus. Mitogenicity...
Mitochondrial control region and 12S rRNA variation in Przewalski’s horse (Equus przewalskii). Variation in the control region and the 12S rRNA gene of all surviving mitochondrial lineages of Przewalski's horse was investigated. Variation is low despite the present day population being descended from 13 individuals probably representing animals from three different regions of its range. Phylogenetic comparison of these sequences, with sequences for the domestic horse, does not resolve the ancestral status of either horse.
Pressure and temperature dependence of enantioselective excited-state quenching of chiral Tb(III) and Eu(III) tris(pyridine-2,6-dicarboxylate) chelates by various C-type ferricytochromes. For mitochondrial ferricytochrome c from horse, cow and tuna and for bacterial cytochrome c-550 from Paracoccus versutus, the pressure and temperature dependence of their quenching of racemic Tb(DPA)3(3-) and Eu(DPA)3(3-) (DPA = pyridine-2,6-dicarboxylate) luminescence in aqueous solution is investigated. Of these energy transfer reactions the activation volumes (delta V#) and energies (Ea) are determined for the ranges P = 0-3 kbar and T = 15-40 degrees C. For the lambda enantiomers of Tb(DPA)3(3-) and Eu(DPA)3(3-), delta V# and Ea are almost the same for all proteins: 0.4 < or = delta V# ...
Carboxymethylated phosphatidylethanolamine in mitochondrial membranes of mammals–evidence for intracellular lipid glycoxidation. The non-enzymatic modification of aminophospholipids with lipoperoxidation-derived aldehydes and glycoxidation-derived products have been reported previously. However, it remains unknown whether intracellular membranes are damaged by these glycoxidation-derived products. To investigate this issue, we tested whether aminophospholipids from mitochondrial membranes are damaged by glycoxidative stress the mitochondrion being identified as the major site of reactive-species production in the cell. We have used a selected-ion-monitoring/gas-chromatography/mass-spectrometry assay for carboxymethyleth...
Skeletal muscle adaptations to prolonged training, overtraining and detraining in horses. Thirteen standard-bred horses were trained intensively for 34 weeks and detrained for 6 weeks to study skeletal muscle adaptations to prolonged training, overtraining and detraining. Training included endurance (phase 1, 7 weeks), high-intensity (phase 2, 9 weeks) and overload training (OLT) (phase 3, 18 weeks). During phase 3, horses were divided into two groups, OLT and control (C), with OLT horses performing greater intensities and durations of exercise than C horses. Overtraining was evident in OLT horses after week 31 and was defined as a significant reduction in treadmill run time in res...
Cryopreservation of equine embryos with glycerol plus sucrose and glycerol plus 1,2-propanediol. Six or 7-day-old equine embryos were divided into 4 groups; Group 1, n = 15, Day 7 embryos destined for immediate transfer; Group 2, n = 15, Day 6 embryos destined for deep-freezing with glycerol plus sucrose as cryoprotectant; Group 3, n = 10, Day 6 embryos destined for deep-freezing with glycerol plus 1,2-propanediol as cryoprotectant and Group 4, n = 3, fresh embryos destined for ultrastructural analysis. All the frozen/thawed embryos were transferred to recipient mares, except 3 embryos in Group 3 that were subjected to ultrastructural analysis. After thawing the cryoprotectants were remov...
Skeletal muscle histology and biochemistry of an elite sprinter, the African cheetah. To establish a skeletal muscle profile for elite sprinters, we obtained muscle biopsy samples from the vastus lateralis, gastrocnemius and soleus of African cheetahs (Acinonyx jubatus). Muscle ultrastructure was characterized by the fiber type composition and mitochondrial volume density of each sample. Maximum enzyme activity, myoglobin content and mixed fiber metabolite content were used to assess the major biochemical pathways. The results demonstrate a preponderance of fast-twitch fibers in the locomotor muscles of cheetahs; 83% of the total number of fibers examined in the vastus laterali...
An introduction to mammalian interspecific hybrids. Haldane's law states that in interspecific hybrids, it is the heterogametic sex that is likely to be absent, rare, or sterile. In mammals, there is increasing evidence to suggest that this may be due to the high mutation rate of male sex-determining genes on the Y chromosome. The mule, humanity's first successful attempt at genetic engineering, provides some support for this concept. Interspecific hybrids may also shed new light on the importance of the maternal transmission of mitochondrial DNA and the phenomenon of genomic imprinting.
Glyceraldehyde 3-phosphate dehydrogenase is bound to the fibrous sheath of mammalian spermatozoa. Evidence is provided that the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase is covalently linked to the fibrous sheath. The fibrous sheath is a typical structure of mammalian spermatozoa surrounding the axoneme in the principal piece of the flagellum. More than 90% of boar sperm glyceraldehyde 3-phosphate dehydrogenase activity is sedimented after cell disintegration by centrifugation. Detergents, different salt concentrations or short term incubation with chymotrypsin do not solubilize the enzyme, whereas digestion with trypsin or elastase does. Short term incubation with trypsin...
Assessment of viability and mitochondrial function of equine spermatozoa using double staining and flow cytometry. An objective double-staining method was developed to evaluate viability and mitochondrial function of stallion spermatozoa using flow cytometry. Sperm viability was assessed by propidium iodide (PI) exclusion, and mitochondrial function was measured by the intensity of rhodamine 123 (R123) fluorescence. Flow cytometry estimates of sperm viability measured by PI were equivalent (P > 0.05) to estimates made using Hoechst 33258 stain and fluorescent microscopy (% dead: 25 +/- 2.4 vs 21.5 +/- 3.5). The use of both PI and R123 was validated by addition of various proportions of freeze-shocked (m...
Persistent hyperammonemia in two related Morgan weanlings. Persistent hyperammonemia was diagnosed in 2 Morgan fillies with clinical signs that developed early in the postweaning period. Diagnostic evaluation, including routine serum chemistries, CBC, liver biopsy, hepatic ultrasonography, liver function test, and necropsy findings did not support a toxic, developmental, or infectious cause. Abnormal serum amino acid and urine orotic acid concentrations suggest that the foals may have had an inherited disorders described in humans as hyperornithinemia, hyperammonemia, and homocitrullinuria (HHH) syndrome. The disorder is thought to be caused by a defe...
Protonophoric activity of NADH coenzyme Q reductase and ATP synthase in coupled submitochondrial particles from horse platelets. A method to prepare coupled submitochondrial particles from horse platelets is described. The method allowed us to study the protonophoric activities of both complex I and complex V following the fluorescence quenching of the monoamine 9-amino-6-chloro-2 methoxyacridine (ACMA), a probe highly sensitive to the generation of a transmembrane delta pH. We carried out a kinetic analysis of each enzyme complex studying the proton translocation and the electron transfer activities of complex I as well as the proton translocation and the ATP hydrolytic activities of complex V. A micromethod to prepare...
The effects of ischemia and reperfusion on mucosal respiratory function, adenosine triphosphate, electrolyte, and water content in the ascending colon of ponies. The purpose of this study was to examine the effects of ischemia and reperfusion on the biochemical integrity of equine colonic mucosa to assess the relative roles of ischemic- and reperfusion-induced damage. Methods: Two hours of no-flow ischemia experimentally induced by 720 degrees counterclockwise ascending colon volvulus followed by 2 hours reperfusion after derotation. Methods: Ten ponies. Methods: Ascending colon biopsies were obtained every hour for measurement of mucosal adenosine triphosphate (ATP), water, sodium, and potassium content. Additional samples were homogenized for assay o...
Oxidative energy metabolism in equine tendon cells. Hypoxia has been suggested as a possible cause of tissue degeneration and subsequent rupture in equine tendons. To determine whether low oxygen tension is likely to be detrimental to tendon cell function, experiments were designed to investigate oxidative energy metabolism in freshly isolated and cultured equine tendon cells. Freshly isolated tenocytes and cultured fibroblasts possessed activities of the mitochondrial enzyme citrate synthase similar to those of other mammalian cells, with well defined oxidative metabolism. D-[6(-14)C]-glucose oxidation was measurable in both freshly isolated a...
Myoglobin content and oxygen diffusion: model analysis of horse and steer muscle. We test the hypothesis that myoglobin is important for O2 supply near the oxidative capacity of muscle. This hypothesis is evaluated with a simple model that incorporates the properties of heart and skeletal muscle tissue taken from steers and horses exercising at their maximum O2 consumption rate. These tissue samples allowed us to set the bounds on oxidative demand and O2 flux from red blood cells to the core of the muscle fiber, to estimate the blood and tissue capacities for O2 diffusion, and to define the capillary blood PO2 driving this O2 flux. A model combining blood convection with ti...
Studies into aromatase activity associated with fetal allantochorionic and maternal endometrial tissues of equine placenta. Identification of metabolites by gas chromatography mass spectrometry. Maternal endometrial and fetal allantochorionic tissues were separated manually from the placentae of seven healthy thoroughbred and three pony mares, ranging in gestational age from 100 to 318 days. The homogeneity of subcellular fractions prepared from these tissues was assessed initially using the marker enzymes, succinate dehydrogenase, NADPH cytochrome C reductase and lactate dehydrogenase for the mitochondrial, microsomal and cytosolic fractions, respectively. Light microscopy and histochemical analysis demonstrated that the separated fetal allantochorionic membrane, which is made up of ...
The complete mitochondrial DNA (mtDNA) of the donkey and mtDNA comparisons among four closely related mammalian species-pairs. The nucleotide sequence of the complete mitochondrial genome of the donkey, Equus asinus, was determined. The length of the molecule is 16,670 bp. The length, however, is not absolute due to pronounced heteroplasmy caused by variable numbers of two types of repetitive motifs in the control region. The sequence of the repeats is (a) 5'-CACACCCA and (b) 5'-TGCGCGCA, respectively. The order of (a) and (b) can be expressed as {n[2(a)+(b)]+m(a)}. In 32 different clones analyzed the number of n and m ranged from 0 to 9 and 1 to 7. The two rRNA genes, the 13 peptide-coding genes, and the 22 tRNA gene...
PCR-RFLP analysis of the cytochrome b gene in horse mitochondrial DNA. The mitochondrial DNA sequence of cytochrome b gene in a Thoroughbred horse was determined. By comparing DNA sequences between the Thoroughbred and published sequence data (two horses and one Grevyi zebra), polymerase chain reaction (PCR) primers were designed for amplification of a 590 bp DNA fragment in the cytochrome b gene, and PCR-restriction fragment length polymorphism (RFLP) analysis was studied in 140 horses of six breeds using three restriction enzymes (AciI, BamHI, RsaI). Two morphs were found using each of the three enzymes. By combining three enzymes morphs, the 140 horses examine...
Surface plasmon resonance studies of complex formation between cytochrome c and bovine cytochrome c oxidase incorporated into a supported planar lipid bilayer. II. Binding of cytochrome c to oxidase-containing cardiolipin/phosphatidylcholine membranes. Complex formation between horse heart cytochrome c (cyt c) and bovine cytochrome c oxidase (cco) incorporated into a supported planar egg phosphatidylcholine membrane containing varying amounts of cardiolipin (CL) (0-20 mol%) has been studied under low (10 mM) and medium (160 mM) ionic strength conditions by surface plasmon resonance (SPR) spectroscopy. Both specific and nonspecific modes of cyt c binding are observed. The dissociation constant of the specific interaction between cyt c and cco increases from approximately 6.5 microM at low ionic strength to 18 microM at medium ionic strength, ...
Theoretical predictions of end-capillary PO2 in muscles of athletic and nonathletic animals at VO2max. Characterizing the resistances to O2 transport from the erythrocyte to the mitochondrion is important in understanding potential transport limitations. A steady-state model of this process was developed to predict the minimum (critical) end-capillary PO2 required to prevent hypoxia at maximal O2 consumption (VO2max) in a circular region of tissue surrounding the venular end of a capillary. Capillary density was used as a measure of O2 delivery, and mitochondrial density was used as a measure of O2 consumption. The effects of oxyhemoglobin dissociation kinetics and diffusion facilitation by hem...
In vitro maturation and transmission electron microscopic observation of horse oocytes after vitrification. The study was designed to examine the suitability of immature horse oocytes for vitrification. Immature oocytes derived from slaughtered horse ovaries were transferred to a vitrification solution (EFS; 40% ethylene glycol, 18% Ficoll, and 0.3 M sucrose in modified phosphate-buffered saline) directly (Groups 1 and 4) or were first exposed to 20% ethylene glycol solution for 10 min (Groups 2 and 5) or 20 min (Groups 3 and 6). Oocytes were handled at 20 degrees C (Groups 1, 2, and 3) or 30 degrees C (Groups 4, 5, and 6). After vitrification and warming, their viability was assessed by maturation ...
Cardiac rod body: hypertrophic Z-line in an aged pony. Numerous rod bodies were found in a heart sample from a 33-year-old pony by a conventional electron-microscopic technique. The rod bodies were concentrated in localized areas of both atria and ventricles, without a specific pattern of distribution. The rods appear to have a typical crystalline-like structure which presumably contains actin backbone filaments and alpha-actinin as major protein constituents. Diminution, fragmentation, and disorganization of the myofibrils, random expansion of electron-dense materials, especially at the fasciae adherens of the intercalated disc, an increase of in...
Causes of differences in respiration rate of hepatocytes from mammals of different body mass. Resting O2 consumption of hepatocytes isolated from mammals ranging in mass from 20-g mice to 200-kg horses decreases with increasing body mass. The substrate oxidation system increases in activity with increasing body mass and mitochondrial proton leak and phosphorylation system decrease in activity, resulting in a higher mitochondrial membrane potential in hepatocytes from larger mammals. The absolute rates of O2 consumption due to nonmitochondrial processes, substrate oxidation, mitochondrial proton leak, and the phosphorylation system decrease with increasing body mass. These decreases are...
Mitochondrial DNA sequences of various species of the genus Equus with special reference to the phylogenetic relationship between Przewalskii’s wild horse and domestic horse. The noncoding region between tRNAPro and the large conserved sequence block is the most variable region in the mammalian mitochondrial DNA D-loop region. This variable region (ca. 270 bp) of four species of Equus, including Mongolian and Japanese native domestic horses as well as Przewalskii's (or Mongolian) wild horse, were sequenced. These data were compared with our recently published Thoroughbred horse mitochondrial DNA sequences. The evolutionary rate of this region among the four species of Equus was estimated to be 2-4 x 10(-8) per site per year. Phylogenetic trees of Equus species demo...
Extensive mtDNA diversity in horses revealed by PCR-SSCP analysis. The hypervariable D-loop region of mitochondrial DNA (mtDNA) was amplified with the polymerase chain reaction using total horse DNA samples. Analysis of single strand conformation polymorphism (SSCP) of denatured amplification products was carried out by native polyacrylamide (8%) gel electrophoresis followed by silver staining. As many as 15 distinct SSCP variants were revealed when screening a total of 78 maternally unrelated horses representing five different breeds. All breeds showed a high degree of polymorphism and the estimated probability (PImt) that two maternally unrelated individual...
