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.
Adhesion and proliferation of human dermal fibroblasts on collagen matrix. The purpose of this study was to evaluate adhesion and growth of human dermal fibroblasts on a 0.150 mm-thick matrix of reconstituted collagen isolated from horse tendon. Collagen was extracted and polymerized according to the standard procedures (Opocrin, Corlo, Modena, Italy). By light microscopy, the bottom surface of the matrix appeared linear and compact, whereas the superficial one was indented and less homogeneous. By scanning electron microscopy, the collagen fibrils had different diameters and the great majority of them was oriented parallel to the surface of the gel. By transmission ...
A low-level X chromosome mosaicism in mares, detected by chromosome painting. Fluorescence in situ hybridization with the use of the equine X whole chromosome painting probe was carried out on chromosome spreads originating from three mares with poor reproductive performance (infertility, miscarriage or stillbirth). The numbers of analysed spreads were high (105, 300 and 480) and in all three mares a low frequency of mosaicism was identified. The mares had the following karyotypes: 64,XX/63,X/65,XXX (93.6%/5.7%/0.7%), 64,XX/63,X (98.9%/1.1%) and 64,XX/63,X (94.3%/5.7%). The incidence and importance of the low percentage X chromosome mosaicism are discussed.
Fetal development of the segment-specific papillary body in the equine hoof. Fetal development of the unique papillary body and its localized peculiarities in the equine hoof are described based on the study of 51 fetuses, nine newborn foals, and five adult horses. The shape and dimensions of the dermal papillae and lamellae have a formative influence on the structure and physical quality of the corneous hoof capsule with its horn tubules and lamellae. The size and arrangement of these horn structures determine the mechanical quality of hoof horn. Proper horn quality is a prerequisite for the various functions of the hoof capsule, such as protecting the living dermis s...
The shielding effect of glycerol against protein ionization in electrospray mass spectrometry. Most commercial recombinant proteins used as molecular biology tools, as well as many academically made preparations, are generally maintained in the presence of high glycerol concentrations after purification to maintain their biological activity. The present study shows that larger proteins containing high concentrations of glycerol are not amenable to analysis using conventional electrospray ionization mass spectrometry (ESI-MS) interfaces. In this investigation the presence of 25% (v/v) glycerol suppressed the signals of Taq DNA polymerase molecules, while 1% (v/v) glycerol suppressed the ...
On the species specificity of sperm binding and sperm penetration of the zona pellucida. Sperm binding and sperm penetration of the zona pellucida (zp) are regarded as species-specific. In this investigation, the interactions between bovine oocytes and porcine, respectively, equine spermatozoa have been studied under in vitro conditions and compared with the normal in vitro fertilization of bovine oocytes by bovine sperm. Surprisingly, many of the heterologous spermatozoa adhered firmly to the bovine oocytes and could not be removed by intense washing. On average, more than 100 boar or equine spermatozoa were bound to the zp of bovine oocytes. Electron microscopic studies clearly ...
[The phylogenesis of equine teeth]. Phylogenetic research on the teeth of equidae beginning with dagger Hyracotherium ('Eohippus') will be summarized, subdivided into its components, analysed in a new way and finally interpreted according to several theories of evolution. In this context, specific cells (ameloblasts, odontoblasts, cementoblasts) are discussed and valued according to Preuss (1987) as active carriers of the evolution of teeth.
Seasonal analysis of the number of aeropiles in Anocentor nitens (Neumann, 1897) (Acari: Ixodidae) from the State of Rio de Janeiro, Brazil. Variation between aeropile numbers of the right and left peritrematic plate in male and female Anocentor nitens (Neumann, 1897) is reported from a site in Brazil. From January to December 1998, 146 males and 247 females of A. nitens were recovered from Equus caballus L. in Silva Jardim District, State of Rio de Janeiro. Asymmetry of numbers of aeropiles between right and left plates occurred in 83.6% of the males and 82.2% of the females. Differences in the number of aeropiles between the sexes were not significant. Quantitative variation of aeropiles was correlated to the period of recovery, ...
Rate of intrachain contact formation in an unfolded protein: temperature and denaturant effects. We have measured the effect of temperature and denaturant concentration on the rate of intrachain diffusion in an unfolded protein. After photodissociating a ligand from the heme iron of unfolded horse cytochrome c, we use transient optical absorption spectroscopy to measure the time scale of the diffusive motions that bring the heme, located at His18, into contact with its native ligand, Met80. Measuring the rate at which this 62 residue intrachain loop forms under both folding and unfolding conditions, we find a significant effect of denaturant on the chain dynamics. The diffusion of the cha...
Tubular structures associated with Babesia caballi in equine erythrocytes in vitro. In-vitro-propagated Babesia caballi parasites were examined by scanning and transmission electron microscopy. Many small pores were observed over the entire surface of infected erythrocytes on scanning electron microscopy, and on transmission electron microscopy these small pores were found to be openings of tubular structures. By the examination of a number of infected cells the tubular structures were found to be connected with the parasite, and this observation might indicate that the tubular structures arose the edge of the parasite and terminated at an Invagination on the surface of the e...
Equilibrium and kinetics of the folding of equine lysozyme studied by circular dichroism spectroscopy. The equilibrium unfolding and the kinetics of unfolding and refolding of equine lysozyme, a Ca2+-binding protein, were studied by means of circular dichroism spectra in the far and near-ultraviolet regions. The transition curves of the guanidine hydrochloride-induced unfolding measured at 230 nm and 292.5 nm, and for the apo and holo forms of the protein have shown that the unfolding is well represented by a three-state mechanism in which the molten globule state is populated as a stable intermediate. The molten globule state of this protein is more stable and more native-like than that of alp...
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...
Cryopreservation of equine embryos. Principles and procedures for cryopreservation of equine embryos are described. Embryos less than 250 microM in diameter can be cryopreserved successfully if glycerol is used as the cryoprotectant. Cooling is takes place in such a way that most of the water leaves the cells before intracellular ice forms, and glycerol is removed after thawing without undue osmotic swelling of cells. Vitrification procedures also show promise for small embryos. Satisfactory procedures for cryopreserving embryos of more than 250 microM in diameter are not yet available.
Microscopic anatomy of the equine skin with special reference to the dermis. We have observed and re-evaluated the histology of the skin of the horse, using samples from four Thoroughbreds. The skin was composed of the usual three components: epidermis, dermis and subcutis. In particular, the dermis was found to have three fibrous components: a papillary layer, a reticular layer and a cordovan-leather tissue layer. The cordovan-leather tissue layer was subdivided into a superficial main layer and a deeper accessory layer. The superficial main layer was thick, and present in all of the skin samples. The deeper accessory layer was found in the dorsal and dorso-lateral pa...
[Tapeworms, a problem in equine practice?]. This paper gives a survey on biology and ecology of equine tapeworms as well as on pathogenesis, clinics, diagnosis, therapy, and prophylaxis of tapeworm infections.
The role of nitric oxide in the responses of equine digital veins to vasodilator and vasoconstrictor agents. Isolated equine digital veins were examined in vitro to study the importance of the endothelium in the responses to both vasodilator and vasoconstrictor agents and to characterise the endothelial-derived mediators involved. Carbachol (Cch; 1 microM) and bradykinin (Bk; 1 nM) caused relaxation of U44069-induced tone by 79.5 +/- 0.35% and 73.7 +/- 4.0% respectively. Mechanical removal of the endothelium completely prevented relaxant responses to Cch and to Bk showing they were mediated by the endothelium. Treatment of veins with NG-nitro-L-arginine methyl ester (L-NAME; 30 and 300 microM) inhibi...
Comparative aspects of Na(+)-K+ and Ca(2+)-Mg2+ ATPase in erythrocyte membranes of various mammals. This work is a comparative study of Na(+)-K+ and Ca(2+)-Mg2+ ATPase associated with the erythrocyte plasma membranes in different mammals. The method used to test the activity of these enzymes is based on quantitative measurements of ADP released during the reaction with HPLC: the chromatographic type is an Ion-Pair Reversed Phase. We have found that the levels of Ca2+ stimulated ATPase are higher than those of Na(+)-K+ ATPase in red blood cells of all the different mammalian species, with the only exception being lamb erythrocytes where the values of both the ATPase activities are almost equa...
Studies on glycoprotein-derived carbohydrates. This research focuses on the study of glycoproteins, specifically investigating their carbohydrate chains and their various functions in living organisms. The article highlights the challenges in isolating specific carbohydrate chains […]