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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.
Influence of several perturbants on the rate of autoxidation of horse heart ferrocytochrome c. The effect of several different types of perturbants and pH on the rate of autoxidation of horse heart ferrocytochrome c was investigated. The kinetic behavior is unique to each perturbant used. Rates of autoxidation followed first-order kinetics over the time span (0-180 min) studied. The Cl- and Br- anions exhibit an initial increase in the rate of autoxidation up to 100 mM, followed by a decrease in kinetics at 500 mM anion concentration. The ClO4- anion exhibits only an increase in the rate of autoxidation with increasing ionic strength, where as, propylurea, a hydrophobic perturbant, is n...
Distribution of enzymes of purine metabolism in lymphocytes of horse, Equus caballus. A microassay requiring as few as 2 X 10(5) cells per assay was developed for systematic analysis of 9 purine enzymes in lymphocytes from equine peripheral blood, spleen, lymph node, thymus and bone marrow. The activities of adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenosine kinase (AK), deoxyadenosine kinase (dAK), deoxycytidine kinase (dCK), 5'-nucleotidase (5'-N), AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase (HGPRT or HPRT), and adenine phosphoribosyl transferase (APRT) were measured by this microassay in lymphocytes from peripheral blood from four ...
Seasonal changes in blood serum protein fractions and in activity of AspAT and AlAT in Arabian brood mares and their foals. In 34 pure breed Arabian horses divided into four groups (Gr. I--10 pregnant mares, Gr. II--7 barren mares, Gr. III--10 foals born in 1981, Gr. IV--7 foals born in 1982) seasonal changes in total blood serum protein, its electrophoretic fractions and the activity of AspAT and AlAT were studied. Seasonal cyclicity was found in all groups in the amount of total serum proteins, and alpha 2- and beta 1-globulin fractions. Cyclicity was found in the level of albumin and activity of AspAT in three groups, not Gr. II, and in gamma-globulin, not Gr. IV. beta 2-globulin and AlAT cyclicity was found in ...
Quantification of unscheduled DNA synthesis in mononuclear leukocytes of the horse. This study compares the relationship between N-acetoxy-2-acetylaminofluorene (NA-AAF) and u.v. induced unscheduled DNA synthesis (UDS) and their respective relationships to age and blood pressure in horse mononuclear leukocytes with earlier, similar investigations on human leukocytes. U.v. induced UDS was found to proceed more rapidly than NA-AAF induced UDS. A pronounced lag period associated with the rapid demand for 3H-dThd into DNA after u.v. damage was observed. NA-AAF induced UDS correlated significantly with NA-AAF binding, age and the blood pressure of male horses. UDS values, induced ...
Horse leucocyte proteinase-inhibitor system. Kinetic parameters of the inhibition reaction. Horse leucocyte neutral proteinase inhibitor reacts with all tested elastases at the molar ratios of 1:1 and yielding stable complexes (Ki = 10(-10) M). The above reactions are very rapid, characterized by the high values of association rate constant kon = 10(7) M-1s-1.
Fatigue characteristics and biocompatability of a totally implantable bone growth stimulator in ponies. Materials fatigue and gross biocompatability of an implantable bone growth stimulator (BGS) were assessed in a 6-month trial using 6 ponies. The forelegs of each pony were implanted with a BGS; the right leg implant had the cathode and cathode lead preconnected by the manufacturer, and the left leg implant was connected at surgery. Evaluation was by radiographic and clinical examination at the beginning and end of the experimental period. Six of the 12 cathode leads (50%) and 7 of the 12 cathodes (58%) were broken at 6 months. All of the implanted preconnected cathode and insulated cathode lea...
Three-year study on trace mineral concentration in the blood plasma of Shetland pony mares. Changes in some trace minerals concentrations (calcium, inorganic phosphorus, magnesium, zinc, iron, copper, sodium and potassium) in blood plasma were investigated during a three-year period in Shetland pony mares. Blood plasma mineral concentrations were determined by the atomic absorption method and colorimetric method. The three-year averages were in micrograms/ml; Na 4630 +/- 168; K 277 +/- 3.8; Ca 171 +/- 3.8; P 31.5 +/- 0.74; Fe 1.92 +/- 0.14; Zn 1.07 +/- 0.04 and Cu 1.06 +/- 0.02. Two trace minerals (magnesium in inorganic phosphorus) showed only long-term tendency changes--upward or d...
The oxygen affinity of mammalian hemoglobins in the absence of 2,3-diphosphoglycerate in relation to body weight. We studied the oxygenation of mammalian hemoglobins: mouse (Mus musculus molossinus), rabbit (Oryctolagus cuniculus domesticus), Japanese monkey (Macaca fuscata), man (Homo sapiens), sheep (Ovis aries), llama (Lama glama), pig (Sus scrofa domesticus), cow (Bos taurus domesticus) and horse (Equus caballus), in the absence of 2,3-diphosphoglycerate (DPG) and compared their oxygen affinity in relation to the body weight. The negative correlation between body weight and the oxygen affinity of the whole blood, observed by Schmidt-Nielsen and Larimer (1958), was not observed in the absence of DPG. O...
Gluconeogenesis from caecal propionate in the horse. The production of propionate in the caecum of the horse has been measured in two Shetland-type ponies fitted with caecal and colonic cannulas and fed on hay or on hay and wheat bran. A continuous intracaecal infusion of 14C-labelled sodium propionate was used and samples were obtained from a cannula at the origin of the right ventral colon. A simultaneous intravenous infusion of [2-3H]glucose was used to measure total glucose entry. On a hay diet which provided 177 kJ/kg body-weight per d, mean caecal propionate production was 19.6 (range 17.2-21.2) mg/h per kg body-weight and on a hay and whe...
Metabolic investigations of fibroblasts from horses, Equus caballus, with hereditary severe combined immunodeficiency. In an attempt to determine the metabolic defect causing severe combined immunodeficiency (SCID) in horses in which altered purine metabolism has been observed, various parameters of purine and pyrimidine metabolism were evaluated. The activities of nine purine enzymes (adenosine kinase, purine nucleoside phosphorylase, deoxyadenosine kinase, deoxycytidine kinase, 5'-nucleotidase, AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase, and adenine phosphoribosyl transferase were measured in fibroblasts. All activities determined for SCID horses were normal. Uptake of 10 microM adenosine...
Evaluation of a technique for measurement of gamma-glutamyltranspeptidase in equine urine. gamma-Glutamyltranspeptidase (GGT) activity in equine urine was measured, using an assay developed for use with serum and was found to be reproducible. The GGT activity was measured in samples prepared by serial dilution of exogenous GGT with equine urine, and the activity was determined to be linear between 21 IU/L and 407 IU/L. The behavior of exogenously added GGT was compared in equine serum and urine. The enzyme behaved similarly in both fluids. The GGT activity was measured in serum and urine samples after storage at -20, 4, and 25 C for 24 and/or 72 hours. Enzyme activity decreased afte...
Comparison of fiber types in skeletal muscles from ten animal species based on sensitivity of the myofibrillar actomyosin ATPase to acid or copper. Comparisons were made of the histochemical characteristics of skeletal muscle from 10 animal species. The basic comparison was made from the staining patterns for the myofibrillar actomyosin ATPase produced by preincubation of fresh frozen cross-sections of muscle at alkaline pH (10.30) or acid pH (4.60) with those produced by preincubation in media containing Cu2+ at alkaline pH (10.30), near neutral pH (7.40), or acid pH (4.60). Muscle sections were also stained for reduced nicotinamide adenine dinucleotide tetrazolium reductase and alpha-glycerophosphate dehydrogenase to provide an indicati...
[Enterohepatic cycle of bile acids and erythrocyte survival]. A comparative analysis is made of the correlation between the life of erythrocytes in various species of animals and some parameters of the gallbladder and its secretion. Due attention is paid to the presence of the bladder, its size, and the concentration and intensity of secretion as well as to the effect of the various bile components on the surface tension of water, the water solution of salts, and the erythrocyte membrane. It is believed that both the composition of bile and the structure of erythrocyte membrane are homeostatically determined. It has been found that the mechanism of aging...
A sensitive liquid chromatographic procedure for the analysis of camphor in equine urine and plasma. A sensitive method was required to analyze low levels of camphor in equine urine and plasma. Camphorated oil (20% w/w camphor) was administered topically (6 g) and intratracheally (1 g) to standardbred mares. The drug was extracted from urine and plasma by diethyl ether and analyzed as its 2,4-dinitrophenylhydrazone derivative by reverse phase HPLC with UV detection. The UV detector was set at 368.5 nm and the samples were eluted from the C18 column by 82% acetonitrile in water. The detection limit achieved was about 10 ng/mL urine and about 20 ng/mL plasma. After topical administration, only ...
Endotoxin-induced eicosanoid production by equine vascular endothelial cells and neutrophils. Dispersed equine vascular endothelial cells grown in tissue culture, and freshly isolated neutrophils were used to determine direct effects of endotoxin on cyclooxygenase and lipoxygenase products. Endothelial cells (10(7)/ml) or neutrophils (2 X 10(6)/ml) were incubated with (a) buffer, (b) endotoxin (10 micrograms/ml), (c) endotoxin + flunixin meglumine (10 micrograms/ml), or (d) calcium ionophore, A23187 (10 micrograms/ml). Thromboxane (TxB2), prostacyclin (6-keto-PGF1 alpha), and leukotriene C4 (LTC4) were determined in the incubation fluid by radioimmunoassay. Thromboxane and prostacyclin...
A new surface marker on equine peripheral blood lymphocytes. I. Subpopulations of lymphocytes with receptors for Helix pomatia A hemagglutinin (HP). Untreated and neuraminidase-treated equine peripheral blood lymphocytes were analysed for binding of the A hemagglutinin of the snail Helix pomatia (HP). For optimal staining by direct immunofluorescence, the concentration of neuraminidase had to be increased as compared to that needed for other species. Moreover, higher concentrations of HP were required for optimal staining of equine lymphocytes as compared to lymphocytes from other species. Even so, the maximal number of equine lymphocytes exhibiting positive staining was only about 20%. No, or very few, HP-positive lymphocytes were seen wh...
Microquantitative determination of the distribution patterns of alcohol dehydrogenase activity in the liver of rat, guinea-pig and horse. Microquantitative measurements of ADH-activity were carried out on the livers of male and female rats, guinea-pigs and horses (two geldings and a mare). Lyophilized cryostat sections of liver parenchyma were microdissected the whole way along the sinusoidal length from the terminal afferent vessels to the terminal efferent venule. ADH activity in samples of about 50-150 ng was measured in a microbiochemical assay using the oil-well technique without enzymatic cycling, by direct luminometric determination of NADH. On the basis of the single measurements, mean values of total hepatic ADH activit...
Fluorescence depolarization studies of melanosomal membranes from different sources. In the present paper we report a comparative study of physical properties and biochemical composition of isolated melanosomal membranes extracted from bovine eyes and from an equine spleen melanoma. Some biophysical characteristics of such membranes were obtained by steady-state and time resolved fluorescence spectroscopy using DPH as fluorescent probe. By these methods we have measured both static fluorescence polarization and fluorescence lifetimes and from the experimental data we have calculated the rotational correlation times by Perrin's equation. Since dynamic and static parameters, suc...
Qualitative detection of corticosteroids in equine biological fluids and the comparison of relative dexamethasone metabolite/dexamethasone concentration in equine urine by micro-liquid chromatography-mass spectrometry. Several important corticosteroids were qualitatively determined in the plasma and urine of horses by micro-liquid chromatography-mass spectrometry (micro-LC-MS). The sensitivity and specificity of micro-LC-MS are demonstrated as is the ability of micro-LC-MS to deal with endogenous interferences. In turn, the relative amount of dexamethasone and its major unconjugated metabolite were determined in equine urine by micro-LC-MS; the conclusions drawn are reported.
Unfolding-refolding transition of a hinge bending enzyme: horse muscle phosphoglycerate kinase induced by guanidine hydrochloride. The unfolding-refolding transition of horse muscle phosphoglycerate kinase induced by guanidine hydrochloride was studied under equilibrium conditions using four different signals: fluorescence intensity at 336 nm, UV difference absorbance at 286 and 292 nm, ellipticity at 220 nm, and enzyme activity. From the following arguments, we found that the process deviates from a two-state model and intermediates are significantly populated even at equilibrium: (1) the noncoincidence of the transition curves and (2) the asymmetry of the transition curve obtained from CD measurements. From these differ...
The primary structure of monomeric beta-lactoglobulin I from horse colostrum (Equus caballus, Perissodactyla). beta-Lactoglobulin-like proteins were detected in horse colostrum and normal milk using immunological techniques. In contrast to the beta-lactoglobulins sequenced so far these proteins are monomeric and genetically not homogenous. In this paper we report the first primary structure of a monomeric beta-lactoglobulin from horse colostrum. By means of an automatic liquid-phase sequenator the sequence of peptides obtained by tryptic digestion and by cyanogen bromide cleavage was determined. A limited tryptic digestion and hydrolysis with chymotrypsin provided the necessary overlapping peptides. Th...
Nutritionally variant streptococci from corneal ulcers in horses. Of 24 isolates of nutritionally variant streptococci recovered from equine corneal ulcers, 22 were tested for growth requirements, physiological and biochemical reactions, and susceptibility to different antimicrobial agents. Satisfactory growth was obtained by supplementing blood agar and Todd-Hewitt broth with pyridoxal hydrochloride, and all of the media for the culture and the biochemical testing were supplemented with 0.002% of this substance. Biochemical patterns of 12 of the isolates resembled those of two viridans streptococcal species, Streptococcus intermedius and Streptococcus const...
An investigation of the effect of hesperidin complex and lemon bioflavonoid complex on growth and development of thoroughbred horses. The objective of this study was to determine the effect of Hesperidin Complex and Lemon Bioflavonoid Complex (HC/LBC) on the growth and development of thoroughbred horses. The trial involved twenty-four foals (12 colts, 12 fillies) allotted to treatment shortly after weaning. The study was conducted for a 342-d growing phase and a 153-d training phase, or a total of 495-d. The HC/LBC was included in the test diet at a level calculated to supply the compound at 55 mg X kg body weight-1 X d-1. During the growing phase, average daily gain of colts that received HC/LBC was higher (P less than .05)...
Cholesteryl sulfate: the major polar lipid of horse hoof. The lipids of horse hoof have been analyzed by quantitative thin-layer chromatography. The major components include cholesterol (37-40%), six groups of ceramides (10-15%), and cholesteryl sulfate (15-20%). Free fatty acids are abundant (15.8%) in the outer fully keratinized hoof, but are present at only low levels (3.1%) in the softer hyponychium. The material identified as cholesteryl sulfate was isolated by preparative thin-layer chromatography and characterized by a combination of chemical, chromatographic, and spectroscopic methods. The infrared spectrum of the isolated material had absorp...
Substrate-dependent kinetic behavior of horse plasma cholinesterase: evidence for kinetically distinct populations of active sites. The inhibition of horse plasma cholinesterase by propranolol showed characteristics which depended upon the identity of the substrate used. With butyrylthiocholine as substrate, the inhibition showed a first-order dependence on inhibitor concentration, and was characterized by a Ki of 8 microM (pH 7.4, 20 degrees C). With p-nitrophenylbutyrate as substrate, a biphasic v-1 versus [I] relationship was obtained. The biphasic curve could be resolved into two components, with apparent Ki's of 9 microM and 1.3 mM. Use of butyrylthiocholine as alternative substrate resulted in partial inhibition of p...
