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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.
Possible modification of scar tissue by biochemical methods. This paper reviews some of the biochemical modifications involved in fibrous tissue formation and discusses possible ways of controlling fibrosis in clinical conditions. The lathyritic agents, beta-aminoproprionitrile (BAPN) and penicillamine, appear in certain situations to be able to control fibrosis by blocking the biosynthesis of collagen. There are no compounds that are yet known which are capable of reversing pre-existing fibrosis and future research may perhaps be more profitably directed towards the stimulation of collagen catabolism rather than the inhibition of its synthesis.
Collagen in normal and abnormal tissues. Despite being a very widespread protein, collagen is an unusual molecule possessing a great tensile strength conferred by a rope-like structure and intermolecular crosslinks. Our current knowledge of the biosynthesis of collagen is providing some insights into certain diseases of connective tissue and is also helping us to understand the healing processes of wounds and diseased tissues.
A mechanistic model for butyrylcholinesterase. A plausible mechanism of action of horse serum butyrylcholinesterase is proposed. It includes substrate activation at the level of deacylation. The rate constant for the acylation of the enzyme appears to be much greater than the rate constant for the deacylation, at low substate concentrations. At higher substrate concentrations the rate constants become more similar. No interaction between the four subunits in binding of inhibitors or in the catalysis was observed. There is one esteratic and one anionic site per subunit apparent from labelling studies with [32P]diisopropylfluorophosphate and...
Insensitivity of the ferritin iron core to heat treatment. To test whether the reactivity of ferritin iron is affected by the heat treatment used in ferritin isolation, we prepared ferritin from the same horse spleen with or without heating. Both samples exhibited similar reactivity upon reduction or chelation of iron.
Synthesis of long complementary DNA in the endogenous reaction by equine infectious anemia virus. In the endogenous reverse transcriptase reaction, equine infectious anemia virus is able to synthesize complementary DNA (cDNA) of 8,000 nucleotides in high yield. After 2 h in 50 muM dNTP, about 2.8 mug of cDNA per mg of protein is produced, almost 30% of which is long cDNA. The system thus compares favorably with the other two well-characterized endogenous reaction systems, Moloney murine leukemia virus and avian sarcoma virus. Elongation rates of 100 to 150 nucleotides per min have been observed; these rates are comparable to those seen with purified avian myeloblastosis virus reverse trans...
Radioimmunoassay for PMSG and its application to in-vivo studies. A double-antibody radioimmunoassay for PMSG, especially for meauring PMSG in cattle blood after exogenous application, has been developed. A rabbit antiserum against PMSG and pure PMSG for radioiodination were used. There was a strong cross-reaction against equine LH and FSH, but the slight cross-reaction against bovine LH and FSH could be eliminated by adding bovine LH to each tube during the assay. Unspecific, interfering influences of equine or cow serum could be eliminated by adding a constant amount of PMSG-free serum to each tube. PMSG added to 200 microliter of serum could be recovered ...
The effect of training and detraining on several enzymes in horse skeletal muscle. Training and detraining had little effect on the activity of glycogen synthase, hexokinase, glycerol 3-phosphate dehydrogenase or total protein. The activity of 3-hydroxyacyl-CoA dehydrogenase increased markedly during training. After 5 weeks of detraining, the activity of 3-hydroxyacyl-CoA dehydrogenase was returning to pre-training values, whilst by 10-week detraining, the levels were increasing again.
Lymphocyte specificity to protein antigens. II. Fine specificity of T-cell activation with cytochrome c and derived peptides as antigenic probes. Murine T-lymphocyte specificity was determined in a system of antigen driven in vitro T-cell proliferation using cytochrome c molecules from different species, their derived peptides and reconstituted hybrid proteins. It was observed that primed T cells could discriminate between peptide fragments which differed from each other at a single amino acid residue. These conclusions were substantiated by the pattern of cross-reactivity noted in the response of closely related cytochrome c proteins as well as when artificial hybrid molecules reconstituted by the covalent linkage of peptide fragments ...
Selenium and gamma-glutamyl transferase activity in the serum of thoroughbreds. Selenium and gamma-glutamyl transferase activity has been measured in the serum of clinically health thoroughbreds. The thoroughbreds, whose performance was reported to be unsatisfactory, had consistently low concentrations of selenium and high activity of gamma-glutamyl transferase in the serum when compared with those whose performance was as expected. Vitamin E levels in the serum showed no such difference. The only other biochemical and haematological abnormality was lower serum phosphate concentrations in the unsatisfactory group. These results suggest that low concentrations of selenium ...
Determination of the charge of horse kidney metallothionein by free boundary electrophoresis. Traditionally, the charge of a protein molecule as determined by electrophoresis has been compared to that revealed by pH titration, and any lack of coincidence has been ascribed to ion binding, and the two results have been brought into agreement by adjustment of binding parameters (1). Metallo-thionein allows a unique opportunity to examine the validity of the electrophoretic approach, since the amino acid sequence and metal atom binding studies allow the absolute charge of the molecule to be computed (2). This then can be compared to the charge determined from electrophoretic mobility measu...
Stability of the lyophilized F(ab’)2 fragments of horse tetanus antibodies isolated by affinity chromatography. F(ab')2 fragments of horse tetanus antibodies were obtained from horse hyperimmune sera after peptic digestion. The digest was passed through a column of tetanus toxoid coupled with Sepharose 4B, F(ab')2 fragments were eluted with a solution of 5 mM HCl in 150 mM NaCl and the eluates were concentrated by ultrafiltration and lyophilized. Glycine and human serum albumin were used as stabilizing agents. Polyacrylamide gel electrophoretic mobility and molecular weight of the fragments remained unchanged after lyophilization. Freeze-dried preparations stored two months at 56 degrees C showed only a...
An investigation of the uterine luminal environment of non-pregnant and pregnant pony mares. Uterine flushings were collected from 30 non-pregnant Pony mares on Days 8, 12, 14, 16, 18 or 20 after oculation. Mares were allowed a recovery period of one oestrous cycle and were mated at the next oestrus. They were then ovario-hysterectomized on days which corresponded to the day of the oestrous cycle to which they were assigned. Uterine flushings were analysed for total recoverable protein and acid phosphatase activity. Least squares analysis indicated a status X day interaction for total protein (P less than 0.10) and acid phosphatase activity (P less than 0.005) in which the latter was ...
Specific PGF-2 alpha binding by the corpus luteum of the pregnant and non-pregnant mare. The binding of prostaglandin (PG) F-2 alpha to corpora lutea (CL) from pregnant and non-pregnant Pony mares was examined. Studies of the rates of association and dissociation indicated that [3H]PGF was bound specifically and reversibly to a luteal cell membrane preparation (MP) that was isolated by high speed (100,000 g) ultracentrifugation. Various PGs and PG metabolites displaced [3H]PGF from the receptors in the following decreasing order: PGF-2 alpha greater than 13, 14-dihydro-PGF-2 alpha = 13,14-dihydro-15-keto PGF-2 alpha greater than PGD-2 greater than PGF-1 alpha = PGE-2 greater than ...
The nature of the prealbumin ‘esterases’ of horse serum. Evidence is presented to suggest that the acidic prealbumin esterases in horse serum represent a protease-inhibitory protein. The esterase activity may arise from residual enzymic activity of the bound protease.
Hematological and biochemical values of thoroughbred foals in the first six months of life. Hematological and biochemical parameters in five Thoroughbred foals during the first six months of life are reported. The samples were analyzed for red blood cell, packed cell volume, hemoglobin, platelet, white blood cell, absolute number for leukocytes, and erythrocyte fragility and serum calcium, inorganic phosphorus, sodium, potassium, chloride, magnesium, alkaline phosphatase, icterus index unit, bilirubin, blood urea nitrogen, nonprotein nitrogen, blood glucose, lacticdehydrogenase, glutamic pyruvic transaminase, glutamic oxalacetic transaminase, total protein, albumin, globulin, and A/G...
Episodic nature of the delta 4-ene and delta 5-ene steroidogenic pathways and their relationship to the adreno-gonadal axis in stallions. Changes in the daily secretory patterns of testosterone and other 17 beta-hydroxyandrogen, total oestrogens and total corticoids were investigated in 7 stallions. Pulsatile fluctuations in plasma hormone levels were found in the serial blood samples collected hourly for 24 h in all animals. The plasma profiles indicated that corticoids, oestrogens and androgens were secreted episodically at all times in stallions. A significant correlation was observed between the precursor and products of delta 4-ene and delta 5-ene pathways and in inverse correlation (r = -0.68; P less than 0.01) was observe...
Catecholamines and equine luteal progestagens. Corpora lutea (CL) from 7 mares were sliced and incubated for 2 h with ovine LH and various sympathomimetic agonists and blockers. None of these compounds was able to cause a significant increase in either progesterone or total progestagens by the luteal tissue. This is in contrast to earlier studies with bovine luteal tissue, and indicates that the equine CL is more refractory to exogenous stimulation than in the bovine CL.
An investigation of seven enzymes as possible genetic markers in horse leucocytes. In this paper we describe seven enzymes, NP, GOTM, PGM2, alpha FUC, PEP A, ADA and MPI which are found in the white cells of horses, including 39 British crossbred ponies and 16 crossbred horses, 30 Mongolian ponies and 10 Icelandic ponies. Two of these enzymes--alpha FUC and MPI--were polymorphic in all the populations of horses studied and could prove useful as additional markers in the paternity testing of horses. PEP A and GOTM were also polymorphic in two of the populations studied and could be used as further markers in these populations.
An enzyme immunoassay (EIA) for progesterone in horse plasma. A simple enzyme immunoassay (EIA) for the measurement of progesterone is described. Antibody against 11-OH-hemisuccinate-BSA is bound to polystyrene tubes. 11-OH-hemisuccinyl-beta-D-galactosidase is used as enzyme-coupled antigen and methylumbelliferyl-beta-D-galactoside as substrate. Concentrations down to 0.156 ng/ml plasm or amounts of 93 pg/tube are detectable. Probit analysis gave a linear relationship between log concentration and percentage of binding. A comparison of EIA and radioimmunoassay gave a correlation coefficient of 0.81. The assay is sufficiently sensitive to estimate progest...
Changes in mammary development and composition of secretion during late pregnancy in the mare. Small samples of mammary secretion were taken for analysis from Thoroughbred mares during the last 3 weeks of pregnancy up to the time of foaling. The concentrations of sodium and chloride decreased while those of lactose, potassium, citrate, phosphate, calcium, magnesium and protein increased. The time-course of these changes showed marked variation between animals. The concentration of whey proteins began to increase about 10 days before parturition. The appearance of the secretion and the size of the mammary glands increased in the last few days of pregnancy. It is suggested that the concen...
DNases in milk and blood sera from different species. DNases were demonstrated in samples of colostrum and blood serum from man and various domestic animals. The measurable DNase activity recorded was highest in samples from cat and dog and lowest in samples from goat, horse, pig and sheep. In contrast to DNases produced by certain bacteria, these enzymes were thermo-labile and the activity was maximal in the area pH 5.0–5.5. A modification of an agar medium originally described for the demonstration of bacterial DNases was found to be suitable for assays of DNases from colostrum, milk and serum. DNaser ble påvist i prøver fra kolostrum og bl...
