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Topic:Biochemistry
The study of biochemistry in horses encompasses the chemical processes and substances that occur within equine organisms. This field investigates the molecular interactions and pathways that are fundamental to horse physiology, including metabolism, enzyme activity, and genetic expression. Key areas of interest include the examination of metabolic disorders, nutrient absorption, and the biochemical basis of muscle function and energy production. Researchers utilize biochemical analysis to understand health and disease mechanisms in horses, contributing to the development of diagnostic tools and therapeutic strategies. This page gathers peer-reviewed studies and scholarly articles that explore various biochemical processes and their implications for equine health and performance.
Distinct roles of GPVI and integrin alpha(2)beta(1) in platelet shape change and aggregation induced by different collagens. 1. Various platelet membrane glycoproteins have been proposed as receptors for collagen, in some cases as receptors for specific collagen types. In this study we have compared the ability of a range of collagen types to activate platelets. 2. Bovine collagen types I-V, native equine tendon collagen fibrils and collagen-related peptide (CRP) all induced platelet aggregation and shape change. 3. Responses were abolished in FcRgamma chain-deficient platelets, which also lack GPVI, indicating a critical dependence on the GPVI/FcRgamma chain complex. 4. Responses to all collagens were unaffected in...
Monocarboxylate transporters and lactate metabolism in equine athletes: a review. Lactate is known as the end product of anaerobic glycolysis, a pathway that is of key importance during high intensity exercise. Instead of being a waste product lactate is now regarded as a valuable substrate that significantly contributes to the energy production of heart, non-contracting muscles and even brain. The recent cloning of monocarboxylate transporters, a conserved protein family that transports lactate through biological membranes, has given a new insight into the role of lactate in whole body metabolism. This paper reviews current literature on lactate and monocarboxylate transpo...
Serum concentrations of keratan sulfate, osteocalcin, and pyridinoline crosslinks after oral administration of glucosamine to standardbred horses during race training. To determine the effects of orally administered glucosamine on concentrations of markers of bone and cartilage metabolism in Standardbred horses during race training. Methods: Twenty 16- to 20-month-old Standardbreds beginning race training. Methods: Horses were randomly assigned to 2 groups. One group received glucosamine hydrochloride (4 g, PO, q 12 h), and the second (control) group received glucose (4 g, PO, q 12 h). Serum samples were obtained prior to onset of the study (baseline) and at regular intervals for 48 weeks for determination of concentrations of keratan sulfate (KS), osteocalc...
Effect of prolonged water immersion on equine hoof epidermis in vitro. To evaluate the effect of prolonged water exposure on tissue mass and solutes of outer and inner layers of the stratum medium, sole, frog, and the stratum medium (SMZA) zona alba layer of horses' hooves. SPECIMEN POPULATION: 10 hooves from 10 horses without foot abnormalities. Methods: Hoof wall tissue specimens were obtained and immersed for 10 days in distilled deionized water. Serial changes in mass were recorded during the immersion period. Subsequently, osmolarity and Na+, K, Cl-, and protein concentrations of the immersion solution were quantified. Results: Fully cornified outer hoof wal...
Nitric oxide synthase inhibition speeds oxygen uptake kinetics in horses during moderate domain running. Within the moderate exercise intensity domain, the speed of oxygen uptake (V(O(2))) kinetics at the transition to a higher metabolic rate is thought to be limited by an inertia of the oxidative machinery. Nitric oxide (NO)-induced inhibition of O(2) consumption within the electron transport chain may contribute to this inertia. This investigation tested the hypothesis that a reduction or removal of any such NO effect via infusion of N(omega)-nitro-L-arginine methyl ester (L-NAME; a NOS inhibitor) would speed V(O(2)) kinetics at the onset of moderate exercise. Five Thoroughbred geldings underwe...
Effect of extraction time and acid concentration on the separation of proglycogen and macroglycogen in horse muscle samples. The objective of this study was to determine whether the concentrations of proglycogen (PG) and macroglycogen (MG) in biopsy samples of horse muscle are influenced by extraction time or perchloric acid (PCA) concentration. In study 1, individual muscle-biopsy samples from 10 horses were divided into 4 parts each and then randomly subjected to 4 periods of extraction (10, 20, 60, or 120 min) with 1.5 M PCA. In study 2, individual muscle-biopsy samples from 6 horses were divided into 24 pieces each and then randomly subjected to 12 combinations of extraction time (10, 20, 30, or 40 min) and PCA ...
Effects of dietary flaxseed oil supplementation on equine plasma fatty acid concentrations and whole blood platelet aggregation. An 18-week feeding trial was performed to investigate the effects of an omega-3 (n-3) fatty acid-enriched ration on plasma fatty acid concentrations and platelet aggregation in healthy horses. Flaxseed oil served as the source of the n-3 fatty acid alpha-linolenic acid (ALA). Twelve horses were fed dietary maintenance requirements using a complete pelleted ration (80%) and timothy grass hay (20%) for a 2-week acclimation period before being randomly assigned either to a treatment (group 1) or control (group 2) group. Group 2 horses (n = 6) were fed the diet described in the acclimation period,...
Analysis of the variations of follicular fluid composition during follicular growth and maturation in the mare using proton nuclear magnetic resonance (1H NMR). Follicular development and ovulatory processes in mammals involve local biochemical changes as a result of substantial modifications in cellular metabolism, the most well known of which is steroid variation. In the present study, the intrafollicular variation of several other components was studied using proton nuclear magnetic resonance ((1)H NMR). This approach made it possible to demonstrate that the intrafollicular biochemical content changes during follicular growth and maturation. Follicular fluid was aspirated by ovarian puncture of the dominant follicle at various physiological stages ...
Insulin-like growth factor-I and insulin-like growth factor binding protein-2 and -5 in equine seminal plasma: association with sperm characteristics and fertility. The objectives of this study were 1) to determine whether insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) were present in seminal plasma of stallions; 2) to compare semen parameters (IGF proteins, sperm numbers, morphology, and motility) from stallions at sexual rest (SR) and when sexually active (SA); 3) to compare semen parameters between stallions with high and low seminal plasma IGF-I concentrations; and 4) to examine the relationship between seminal plasma IGF-I concentrations and fertility parameters of stallions. Ejaculates were collected fr...
Fourier transform infrared microspectroscopic investigation of the organic and mineral constituents of peritubular dentin: a horse study. Peritubular dentin (PTD) is a relatively dense mineralized tissue surrounding tooth dentin tubules, whose composition and mode of formation are still unclear. Fourier transform infrared microspectroscopic studies of the organic and mineral components of the highly developed horse PTD indicate that the peritubular matrix is less abundant than the intertubular matrix but is also mainly composed of collagen, which is more hydrated. These data suggest that most of the crystals are located outside the collagen fibrils and probably not associated with protein components. The crystals in PTD have nea...
Inactivation of West-Nile virus during peptic cleavage of horse plasma IgG. Peptic cleavage of horse plasma IgG is a common procedure for the preparation of F(ab)(2) products for human use, such as antivenin and antitoxin. The removal of the Fc fragment from the IgG molecule by enzymatic cleavage at low pH, ensures fewer side-effects of the F(ab)(2) product for passive immunotherapy compared with the whole IgG molecule. Since the starting material may be contaminated by zoonotic horse viruses, it is necessary to demonstrate the removal or inactivation of possible viral contaminants. Guidelines for performing such studies were published by the Commission for Plasma-Der...
Determination of the chondroitin sulfate disaccharides in dog and horse plasma by HPLC using chondroitinase digestion, precolumn derivatization, and fluorescence detection. A sensitive and selective HPLC method for the determination of the disaccharides of chondroitin sulfate in horse and dog plasma was validated. Chondroitin sulfate is degraded by chondroitinase ABC to three primary unsaturated disaccharides, (1) 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose, (2) 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose, and (3) 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose, when treated with chondroitinase. Plasma samples (0.5 ml) were treated with 50 mU of chon...
Molecular characterization of the equine AEG1 locus. Acidic epididymal glycoprotein 1 (AEG1), also called cysteine-rich secretory protein 1 (CRISP1), is a member of the CRISP protein family which is characterized by 16 conserved cysteine residues at the C-terminus. The CRISP proteins are expressed in the male genital tract and are thought to be involved in sperm-egg fusion. Therefore, their genes are of interest as candidate genes for inherited male fertility dysfunctions and as putative quantitative trait loci for male fertility traits. In this report, the cloning and DNA sequence of 90 kb of horse genomic DNA from equine chromosome 20q22 conta...
Contribution of heme-propionate side chains to structure and function of myoglobin: chemical approach by artificially created prosthetic groups. Horse heart myoglobin was reconstituted with mesohemin derivatives methylated at the 6- or 7-position to evaluate the role of the heme-6-propionate or heme-7-propionate side chain in the protein. The association and dissociation of the O(2) binding for the deoxymyoglobin with 6-methyl-7-propionate mesoheme are clearly accelerated. Furthermore, the myoglobin with 6-methyl-7-propionate mesoheme shows fast autoxidation from oxymyoglobin to metmyoglobin compared to the myoglobin with 6-propionate-7-methyl heme and the reference protein. These results indicate the 6-propionate plays an important ph...
Effect of withholding feed on concentration and composition of plasma very low density lipoprotein and serum nonesterified fatty acids in horses. To measure and compare the concentration and composition of very low-density lipoprotein (VLDL) in plasma and selected lipids in serum of horses fed mixed grass hay ad libitum or denied feed for 36 hours. Methods: 4 healthy adult mares. Methods: Mares were either fed mixed grass hay ad libitum or denied feed for 36 hours beginning at 8:00 AM. Blood samples were collected every 2 hours during the study period and analyzed for nonesterified fatty acid (NEFA), triglyceride (TG), VLDL, and glucose concentrations and composition of VLDL. Results: Withholding feed significantly increased mean serum ...
Equine oocyte maturation with epidermal growth factor. Epidermal growth factor (EGF) has been shown to have a positive effect during oocyte in vitro maturation in several species. This study was performed to establish the capacity of equine oocytes to undergo nuclear maturation in the presence of EGF and to localise its receptor in the equine ovary by immunohistochemical methods. Oocytes were obtained by aspiration and subsequent scraping from equine follicles (15-25 mm diameter) and cultured in 3 different treatment groups for 36 h: control Group (modified TCM 199 with 0.003% BSA), EGF Group (TCM-199 supplemented with 50 ng/ml EGF) and EMS Group ...
Molecular characterisation of carbohydrate digestion and absorption in equine small intestine. Dietary carbohydrates, when digested and absorbed in the small intestine of the horse, provide a substantial fraction of metabolisable energy. However, if levels in diets exceed the capacity of the equine small intestine to digest and absorb them, they reach the hindgut, cause alterations in microbial populations and the metabolite products and predispose the horse to gastrointestinal diseases. We set out to determine, at the molecular level, the mechanisms, properties and the site of expression of carbohydrate digestive and absorptive functions of the equine small intestinal brush-border memb...
Analysis of protein ions in the range 3000-12000 Th under partial (no discharge) atmospheric pressure chemical ionization conditions using ion trap mass spectrometry. A new approach, based on the use of atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-ITMS), but without a corona discharge, was investigated for application to creating and monitoring protein ions. It must be emphasized that APCI is not usually used in protein analysis. In order to verify the applicability of the proposed method to the analysis of proteins, two standard proteins (horse cytochrome c and horse myoglobin) were analyzed. A mixture of the two proteins was also analyzed showing that this novel approach, based on the use of APCI, can be used in the analysis o...
Development of biochemical heterogeneity of articular cartilage: influences of age and exercise. The objective of this study was to document the development of biochemical heterogeneity from birth to maturity in equine articular cartilage, and to test the hypothesis that the amount of exercise during early life may influence this process. Neonatal foals showed no biochemical heterogeneity whatsoever, in contrast to a clear biochemical heterogeneity in mature horses. The process of formation of site differences was almost completed in exercised foals age 5 months, but was delayed in those deprived of exercise. For some collagen-related parameters, this delay was not compensated for after a...
Recombinant equine growth hormone does not affect the in vitro biomechanical properties of equine superficial digital flexor tendon. To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of normal adult equine superficial digital flexor tendon (SDFT). Methods: Completely randomized design. Methods: Nine Standardbred horses, 6 to 9 years of age with ultrasonographically normal forelimb SDFT. Methods: Six horses were administered intramuscular (IM) rEGH at 10 microg/kg/day for 1 week, and then 20 microg/kg/day for another 5 weeks; 3 horses (control subjects) were administered an equivalent daily volume of sterile water IM. Horses were killed at the end of the 6-week treatm...
The effects of cAMP modulation upon the adhesion and respiratory burst activity of immune complex-stimulated equine neutrophils. Toxic products such as reactive oxygen intermediates released by activated polymorphonuclear neutrophil (PMN) have an important role in the pathophysiology of diseases associated with the deposition of immune complexes (IC) in tissues. IC-induced activation of PMN requires adhesion mediated by integrin adhesion receptors. Of the integrins expressed on PMN, the beta(2) family has been found to be of particular importance for activation of PMN by IC. beta(2) Integrin ligand binding must be activated to enable adhesion to IC. Both activating and inhibitory signals regulate beta(2) integrin ligand...
Cytosolic ratio of malate dehyrogenase/lactate dehydrogenase activity in peripheral leukocytes of race horses with training. The activities of the enzymes involved in the malate-aspartate shuttle and m RNA expression of malate dehydrogenase (MDH), a crucial enzyme for the NADH shuttle that produces ATP in glucose metabolism in the peripheral leukocytes of horses, were measured to investigate the change in metabolic states with training. There were no significant differences in plasma glucose and immunoreactive insulin concentrations between race horses and riding horses, used as a comparable reference. The cytosolic and mitochondrial MDH activities in leukocytes of race horses were significantly higher than those of...
The apo-enzyme content of aminotransferases in healthy and diseased domestic animals. We investigated the apo-enzyme content of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in clinically normal and ill canine, feline, equine and bovine patients. Aminotransferase activity was measured with and without the addition of exogenous pyridoxal-5'-phosphate (P5P). The amount of apo-enzyme was expressed as the percentage change in aminotransferase activity with the inclusion of P5P. The results of aminotransferase assays without P5P (holo-enzyme activity) were highly correlated to the results obtained with P5P (total enzyme activity) in all four species (Spearman r...
Artifactually increased serum bicarbonate values in two horses and a calf with severe rhabdomyolysis. Extremely high bicarbonate (HCO3-) and anion gap values were measured in two horses and a calf using the Hitachi 911 automated serum biochemistry analyzer. All three animals had severe muscle disease as evidenced by markedly increased aspartate aminotransferase and creatine kinase activities. Laboratory error was suspected as the source of the increased HCO3- because values calculated from blood gas analysis were normal. It was hypothesized that increased serum lactate dehydrogenase (LDH) activity and pyruvate concentration overwhelmed the oxamate LDH inhibitor in the enzymatic HCO3- assay, re...
Serum keratan sulphate as a cartilage metabolic marker in horses: the effect of exercise. Keratan sulphate (KS) concentration in sera from resting horses and horses training daily on a racetrack was measured by an inhibition enzyme-linked immunosorbent assay (ELISA) using anti-equine KS antibody 1/14/16H9. For the in-training horses, serum KS concentrations in 2-year-old-horses was significantly higher than 3- or 4-year-old-horses. A higher concentration of serum KS was found in the in-training group than in the long-term resting group in 2-year-old-horses. Serum KS concentration increased remarkably immediately after training in healthy horses, and at 1, 5, 9 and 24 h after traini...
A novel lipoarabinomannan from the equine pathogen Rhodococcus equi. Structure and effect on macrophage cytokine production. Rhodococcus equi is a major cause of foal morbidity and mortality. We have investigated the presence of lipoglycan in this organism as closely related bacteria, notably Mycobacterium tuberculosis, produce lipoarabinomannans (LAM) that may play multiple roles as virulence determinants. The lipoglycan was structurally characterized by gas chromatography-mass spectrometry following permethylation, capillary electrophoresis after chemical degradation, and (1)H and (31)P and two-dimensional heteronuclear nuclear magnetic resonance studies. Key structural features of the lipoglycan are a linear alph...
Characterization of lipoproteins in cerebrospinal fluid of mares during pregnancy and lactation. To measure apolipoproteins in cerebrospinal fluid (CSF) from healthy mares and to determine whether CSF concentrations of apolipoproteins change during pregnancy and lactation. Methods: 5 healthy pregnant mares. Methods: 2 sets of CSF samples were obtained; initial samples were obtained 10 to 30 days before parturition (mean, 18 days; median, 17 days), and second samples were obtained 19 to 26 days after parturition (mean, 23 days; median, 23 days). Cerebrospinal fluid was collected from the lumbosacral subarachnoid space of standing horses by use of routine collection techniques. Cerebrospina...
Effects of formaldehyde fixation on equine platelets using flow cytometric methods to evaluate markers of platelet activation. To investigate the effects of formaldehyde fixation on equine platelets using flow cytometric methods to evaluate markers of platelet activation. Methods: Blood samples from 6 Thoroughbreds. Methods: The degree of fluorescence associated with binding of fluorescein isothiocyanate (FITC)-conjugated anti-human fibrinogen antibody and FITC-annexin V in unactivated and adenosine diphosphate (ADP)-, platelet activating factor (PAF)-, and A23187-activated platelet samples in unfixed and 0.5, 1.0, and 2.0% formaldehyde-fixed samples was assessed by use of flow cytometry. Results: In samples incubated...
Evaluation of leukotriene biosynthetic capacity in lung tissues from horses with recurrent airway obstruction. To evaluate leukotriene (LT) biosynthetic capacity in lung tissue from healthy horses and horses with recurrent airway obstruction (RAO). Methods: Lung parenchyma and airway specimens from 8 RAO-affected and 5 healthy horses. Methods: Horses were stabled for > or = 72 hours. Blood was drawn before euthanasia, after which lung specimens were collected. Tissue strips from small airways and parenchyma were incubated in organ baths with the precursor LTA4 or stimulated with calcium ionophore A23187 or the tripeptide N-formyl-Met-Leu-Phe (fMLP), with or without exogenous arachidonic acid, in the...
High-avidity human serum antibodies recognizing linear epitopes of Borna disease virus proteins. The recent observation that Borna disease virus (BDV)-reactive antibodies from psychiatric patients exhibit only low avidity for BDV antigen called into question their diagnostic value and raised the possibility that antigenically related microorganisms or self antigens caused the production of these antibodies. We further characterized the specificity of these antibodies. Methods: We established a peptide array-based screening test that allows the identification of antibodies directed against linear epitopes of the two major BDV proteins, the nucleoprotein (N) and the phosphoprotein (P). Resu...
