Topic:Biology
The study of biology in horses encompasses the examination of their physiological, genetic, and cellular processes. This field investigates the anatomical structures, reproductive biology, and genetic makeup of horses, offering insights into their growth, development, and adaptation. Researchers focus on various aspects such as equine genetics, which explores hereditary traits and genetic disorders, and equine physiology, which examines the functions of different systems within the horse's body, including the cardiovascular, respiratory, and musculoskeletal systems. This page assembles peer-reviewed research studies and scholarly articles that explore the biological mechanisms and processes in horses, providing a comprehensive understanding of their biological functions and health.
Sequence of the high-activity equine erythrocyte carbonic anhydrase: N-terminal polymorphism (acetyl-Ser/acetyl-Thr) and homologies to similar mammalian isozymes. The amino acid sequence of the high-activity equine erythrocyte carbonic anhydrase (CA-II) has been determined. Two different N-termini are noted, the C1 form having an N-acetyl-serine and the C2 form an N-acetyl-threonine. The sequence of the equine enzyme is most homologous to the human CA-II isozyme, with 224 of the 259 residues being identical.
Characterisation of glycoproteins in the sweat of the horse (Equus caballus). The two major polypeptides H (Mr 49,000) and L (Mr 33,000) of equine sweat have been purified by gel filtration and characterised by gel electrophoresis and compositional analysis. Both H and L are glycoproteins containing sialic acid, neutral sugars, N-acetylglucosamine and N-acetylgalactosamine, but the two polypeptides differ considerably in the extent of glycosylation. H and L also differ in amino acid composition, but both contain only low levels of sulphur containing amino acids and histidine. These glycoproteins may behave as surfactants.
Studies on ticks of veterinary importance in Nigeria. VIII. Differences observed in the biology of ticks which fed on different domestic animal hosts. Ticks of the species Amblyomma variegatum (Fabr.), Boophilus decoloratus (Koch), Boophilus geigyi Aeschl. et Morel, and Hyalomma rufipes Koch were detached from cattle, sheep and horses and the influence of these various hosts on the biology of ticks was investigated. No A. variegatum was found in horses. The parameters studied were preoviposition and oviposition periods, ovipositional capacity, eclosion period, hatching patterns, egg sizes and temperature effect. Although the preoviposition and eclosion periods were similar in each tick species irrespective of the host from which the adults w...
The mechanism of Na+-L-lactate cotransport by brush-border membrane vesicles from horse kidney. Analysis by isotopic exchange kinetics of a sequential model and stoichiometry. The present study determines the characteristics of isotopic Na and lactate exchange under equilibrium conditions in horse kidney brush-border membrane vesicles. The influence of one solute (Na+ or lactate) on the isotopic exchange of the co-transported species (lactate or Na) was analyzed in detail. Analysis of the data suggests that Na and lactate interact sequentially with the carrier. The observed apparent symmetry between the activating effect of low Na concentrations and the inhibiting effect of high Na concentrations on the lactate exchange process suggests that the carrier functions ac...
Comparison of the hydroxyacids from the epidermis and from the sebaceous glands of the horse. The acylglucosylceramides were isolated from the polar lipids of horse epidermis and examined to determine whether the component omega-hydroxyacids are straight chained as in the corresponding lipids from pig epidermis or branched as in horse sebum. The hydroxyacids from horse epidermis were found to be almost entirely straight chained compounds. The results indicate that sebaceous glands, although derived from epidermal cells, have evolved independent pathways of lipid metabolism.
Annular gap junctions of the equine hoof wall. Incidental to studies of keratinization of the equine hoof wall, annular gap junctions were found in the stratum spinosum of the intertubular horn of the stratum medium. Adjacent cells of the stratum spinosum showed extensive gap junctions, and often local invaginations of one cell into another were bound by gap junctions. It is proposed that these invaginations become detached from the cell surface to form the annular gap junctions. Formation of annular gap junctions may be a means of disposing of plasma membrane in response to changes in cell volume or shape occurring in keratinization. Inte...
On-line direct liquid introduction interface for micro-liquid chromatography/mass spectrometry: application to drug analysis. We describe an integrated micro-liquid chromatograph/mass spectrometer (micro-LC/MS) system capable of performing routine determinations for 1--10 ng of drugs and their metabolites extracted from biological fluids. The micro-LC is constructed from conventional "high-performance" liquid-chromatographic instrumentation by using commercially available components. The mass spectrometer is operated in the chemical ionization mode. The direct liquid introduction micro-LC/MS interface can be constructed from commercially available materials. Chromatographic and mass spectral results demonstrate the a...
Mobilization of iron from ferritin by isolated mitochondria. Effects of species compatibility between ferritin and mitochondria and iron content of ferritin. Mitochondria mobilize iron from ferritin by a mechanism that depends on external FMN. With rat liver mitochondria, the rate of mobilization of iron is higher from rat liver ferritin than from horse spleen ferritin. With horse liver mitochondria, the rate of iron mobilization is higher from horse spleen ferritin than from rat liver ferritin. The results are explained by a higher affinity between mitochondria and ferritins of the same species. The mobilization of iron increases with the iron content of the ferritin and then levels off. A maximum is reached with ferritins containing about 1 200 i...
Two equine true hermaphrodites with 64,XX/64,XY and 63,XO/64,XY chimerism. The karyotypes of a Welsh pony and a Standardbred were 64,XX/64,XY and 63,XO/64,XY respectively. Both intersexes were true hermaphrodites with bilateral ovotestes. Neither intersex showed stallion-like behaviour. Each one had an underdeveloped penis, bilateral seminal vesicles and uterine tissue. It would appear that the chimerism in these equine intersexes resulted from double fertilization or fusion of blastocysts. Mosaicism in the Standardbred is a possibility, resulting from loss of a Y chromosome by anaphase lag in an early embryonic XY cell.
Culture of horse oocytes in vitro. Oocytes were removed from follicles 5-30 mm in diameter. The germinal vesicle was present in 69.6% (23/33) of the oocytes at the start of culture, but after 20-24 and 40 h 70.5% (12/17) and 68.2% (43/63) of the oocytes were in metaphase I and metaphase II with first polar body extruded, respectively.
The complete amino acid sequence of horse muscle acylphosphatase. The amino acid sequence of horse muscle acylphosphatase is given in the present paper. The carboxymethylated enzyme consists of a single polypeptide chain of 98 amino acid residues with an acetyl group blocking the NH2 terminus and a tyrosine at the COOH terminus. The calculated molecular weight of the native protein, a mixed disulfide with glutathione, is 11,365. The carboxymethylated protein was cleaved by cyanogen bromide. The three expected fragments were purified; moreover, an additional fragment, derived from a partial failure of cleavage at methionine-24, was purified and characterized....