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Topic:Biotechnology
Biotechnology in horses encompasses the application of biological techniques and tools to enhance equine health, performance, and reproduction. This field includes genetic engineering, cloning, and the development of vaccines and therapeutics tailored to equine physiology. Techniques such as gene editing and stem cell therapy are explored for their potential to address genetic disorders, improve tissue regeneration, and enhance disease resistance in horses. Additionally, advancements in reproductive biotechnology, such as artificial insemination and embryo transfer, contribute to genetic diversity and breeding efficiency. This page compiles peer-reviewed research studies and scholarly articles that investigate the applications, methodologies, and implications of biotechnology in equine science.
Pathway of ultrasound waves in the equine third metacarpal bone. The velocity of ultrasound waves through bone has been used widely as a non-invasive method for assessing bone quality. Accurate measurement of velocity depends on accurate assessment of the distance travelled by the sound wave. It has been argued that the sonic pathway is deflected around the marrow cavity and so does not follow a straight line through the bone; therefore, correction factors have been developed to account for the extra distance travelled. This hypothesis was examined in vitro using sections from the equine third metacarpal bone. Two 1 MHz transducers used with the transmittin...
In vitro development of day-2 equine embryos co-cultured with oviductal explants or trophoblastic vesicles. This study compared the in vitro development of Day-2 equine embryos co-cultured with either trophoblastic vesicles or oviductal explants. Embryos were collected surgically from the oviducts of pony mares 2 d after ovulation and assessed for stage of development. Culture medium was Ham's F12 and Dulbecco's Modified Eagle's Medium (50:50 v/v) in a humidified atmosphere of 5% CO(2) in air at 38.5 degrees C with either trophoblastic vesicles or oviductal explants. The quality score of embryos was assessed daily. After 4 d in culture, embryos were stained (Hoechst 33342) and evaluated with epifluo...
Use of a computerized system for evaluation of equine spermatozoal motility. Three ejaculates from each of 3 stallions were used to evaluate a computerized system (Hamilton-Thorn motility analyzer; HTMA) for measuring equine spermatozoal motility. Variance components (ejaculate-within-stallion, chamber-within-ejaculate, and microscopic field-within-chamber) were determined for each stallion after diluting ejaculates to 25 x 10(6) spermatozoa/ml with a skim milk-glucose seminal extender. The HTMA was compared with frame-by-frame playback videomicrography (VIDEO) for determining: percentage of spermatozoal motility and spermatozoal number in microscopic fields; curviline...
Evolution of placenta-specific gene expression: comparison of the equine and human gonadotropin alpha-subunit genes. Primate and equine species are thought to be unique among mammals in synthesizing placental gonadotropin glycoprotein hormones. Human chorionic gonadotropin (CG) and equine pregnant mare's serum gonadotropin (PMSG) are produced in placenta by the specific activation of a glycoprotein hormone alpha-subunit gene and a corresponding beta-subunit gene. The evolutionary mechanisms for the apparently independent acquisition of tissue specificity were investigated by cloning the 5' flanking region of the equine alpha-subunit gene and comparing the DNA elements and trans-acting factors involved in pla...
Beta-subunits of equine chorionic gonadotropin and lutenizing hormone with an identical amino acid sequence have different asparagine-linked oligosaccharide chains. The glycoprotein hormones, equine chorionic gonadotropin (eCG) and lutenizing hormone (eLH), possess a beta-subunit with an identical amino acid sequence. The Asn-linked oligosaccharide chains of eCG beta and eLH beta were quantitatively liberated as tritium-labeled oligosaccharides by hydrazinolysis followed by N-acetylation and NaB3H4-reduction. Paper electrophoresis in combination with sialidase digestion and solvolytic desulfation indicated that eCG beta contained neutral and sialylated oligosaccharides, while eLH beta contained neutral, sialylated, sulfated, and both sialylated and sulfat...
Isolation of horse IgG with protein A. Horse immunoglobulins were obtained from normal serum defatted with dextran sulfate and precipitated with ammonium sulfate. Eight mg of this preparation was submitted to affinity chromatography with protein A-Sepharose CL-4B. Low temperature (4 degrees C) and a starting buffer at pH 8.0 were conditions required for all IgG subclasses to bind to protein A, even those with low affinity. The IgGs bound to protein A were eluted with glycine buffer at pH 2.8. The yield was about 90%. It is suggested that isolated IgG, instead of whole Igs, be used in serum therapy, reducing the amount of Igs and di...
Nonlinear algorithm for identification of a fiducial marker for various cardiac events. We report on a nonlinear algorithm which identifies R-wave peaks on the surface electrocardiogram, consistent reference points on the left ventricular pressure waveform and the initiation of the QRS complex on the epicardial electrogram. The algorithm has been used to evaluate data from horses, ponies, dogs and humans at rest and during exercise. It permits rapid, accurate evaluation of data on a beat-by-beat basis even with noisy signals and varying waveform configurations. The algorithm facilitates the acquisition of detailed information previously difficult or impossible to obtain by more c...
A new method for continuous recording of motor activity in horses. 1. The use of an electronic recorder for the horse motor activity was described. 2. Examples of different types of motor activities are given in Figs 1-8. 3. The ultradian pattern of activity in all records was stressed. 4. The possibility of receiving of more physiological informations by this type of apparatus is discussed.
Embryonic development after intra-follicular transfer of horse oocytes. A technique was developed in which immature horse oocytes, obtained from slaughterhouse specimens, were transferred to the pre-ovulatory follicle of a mare in vivo, with resulting oocyte maturation, ovulation, fertilization and embryo development. Oocytes were collected from all follicles greater than 3 mm, and were classified as immature, maturing, expanded or denuded. The transfers were performed in the standing, tranquilized mare. The ovary containing the pre-ovulatory follicle was grasped per rectum. A trochar and cannula were placed through the abdominal wall in the flank area, ipsilatera...
Viability and ultrastructure of equine embryos following culture in a static or dynamic system. The viability and ultrastructure of equine embryos were assessed following culture in a static or perifusion system. The percentage change in diameter was greater (P less than 0.025) for embryos in the static treatment (71%) than in the perifusion treatment (33%). Fluorescein diacetate (FD) scores, the percentage of fluorescing cells (FC) and fluorescent intensity (FI), also were greater (P less than 0.05 and P less than 0.01) following static culture than for embryos cultured in the perifusion system. Four of 9 control embryos resulted in pregnancies but no embryos cultured in either system p...
Digital signal analysis of cardiac events in horses and ponies. We have developed a digital signal analysis technique which can be used to evaluate various cardiac events in ponies and horses at rest and during exercise. The algorithm is designed to identify R-wave peaks on the surface electrocardiogram, consistent reference points on the left ventricular pressure waveform and the initiation of the QRS complex on the epicardial electrogram. We have used the technique to evaluate data from 10 horses and ponies at rest, during strenuous exercise and during experimentally-induced coronary artery occlusion. The technique provided rapid and accurate beat-by-bea...
Establishment of equine oviduct cell monolayers for co-culture with early equine embryos. A culture for equine oviduct epithelial cells is described. Primary cultures reached confluence in 5-8 days, forming a monolayer of polygonal cells and remaining morphologically intact for about 20 days. Subcultures were obtained by collecting cells detached spontaneously from the monolayers, and confluence was reached again after 5-7 days. Cells frozen before primary culture were confluent 10-15 days after thawing. Dishes containing confluent cells also were frozen, and some cohesive monolayers formed after thawing. Equine embryos, collected 2 days after ovulation, were cultured alone or with...
Characterization of hydrophobic cores in apomyoglobin: a proton NMR spectroscopy study. A proton nuclear magnetic resonance spectroscopic study of horse apomyoglobin was undertaken in order to define the regions of myoglobin that are and that are not structurally affected by the binding of the prosthetic group. It was found that, in spite of the poor spectral resolution, a number of spin systems could be identified by using standard correlated methods. Four clusters consisting mostly of hydrophobic residues were detected by nuclear Overhauser spectroscopy, two of which involved the tryptophan side chains. Extensive similarities to nuclear Overhauser spectroscopy data collected on...
Equine infectious anemia virus derived from a molecular clone persistently infects horses. A full-length molecular clone of equine infectious anemia virus (EIAV) was isolated from a persistently infected canine fetal thymus cell line (Cf2Th). Upon transfection of equine dermis cells, the clone, designated CL22, yielded infectious EIAV particles (CL22-V) that replicated in vitro in both Cf2Th cells and an equine dermis cell strain. Horses infected with CL22-V developed an antibody response to viral proteins and possessed viral DNA in peripheral blood mononuclear cells, as determined by polymerase chain reaction assays. In addition, horses infected with CL22-V became persistently infe...
Equine monoclonal antibodies recognize common epitopes on variants of equine infectious anaemia virus. Equine-murine xenohybridoma cells were produced using SP2/0 murine myeloma cells and splenic lymph node cells obtained from horses infected with 10(6) TCID50 of single cloned variants of equine infectious anaemia virus (EIAV). The xenohybridomas secreted equine IgG monoclonal antibodies reactive with EIAV in enzyme immunoassays employing purified virus. Seven antibodies were studied in detail. They bound to viral glycoproteins (gp90 or gp45) in radioimmunoprecipitation assays, and reacted with homologous EIAV as well as five other cloned variants of EIAV. When evaluated against a single cloned...
Left ventricular volume determination in the horse by two-dimensional echocardiography: an in vitro study. This study was designed to evaluate the accuracy of two-dimensional echocardiography (2DE) in determining the left ventricular volume (LVV) of the horse in vitro. After examining the shape of the left ventricular silicon rubber casts of four equine hearts, two modified Simpson's rule methods (Model A and Model B) as combinations of conical shapes and one biplane area-length method as a single cone (Model C) were chosen for volume calculations. One long axis and three short axis planes were used for linear and area 2DE measurements, respectively. The ventricular length (L) was calculated from t...
Cultivation of tissue from the matrix of the stratum medium of the equine and bovine hoof walls. Explants from the matrix of the stratum medium of the wall of the equine and bovine hoof each were cultured on a microporous membrane, using a standard culture medium. After incubation at 37 C, the outgrowth was a mixture of keratinocytes and fibroblasts, with predominance of the latter. After incubation at 34 C, the keratinocytes dominated, covering the lateral surfaces of the explant as well as the basal surface. Lateral outgrowth of keratinocytes was observed at the borderline of the original epidermis and at the borderline of the explant's contact with the membrane. Epithelial outgrowth fr...
Culture of 5-day horse embryos in microdroplets for 10 to 20 days. Embryos were recovered from the uteri of mares 5 d after ovulation. Six embryos, all morulae, were placed singly in 200-ul droplets of Ham's F-12 with 10% fetal calf serum and cultured at 37 degrees C in a 5% CO(2) atmosphere. The embryos expanded to form blastocysts by the third day of culture. The blastocysts hatched from their zona pellucida, rather than the zona thinning and flaking off, as occurs in vivo. Hatching from the zona pellucida began on the third day of culture and was complete in five of six embryos by the sixth day. The embryonic capsule, normally present in equine embryos aft...
Crystallization of a calcium-binding lysozyme from horse milk. Crystals of the calcium-containing lysozyme from horse milk have been grown by precipitation with sodium phosphate. The crystals are orthorhombic space group P2(1)2(1)2(1) with cell dimensions a = 53.2, b = 57.1, and c = 38.2 A and contain a single molecule in the asymmetric unit. The crystals are suitable for high resolution x-ray structural analysis.
Phagocytosis of opsonized fluorescent microspheres by equine polymorphonuclear leukocytes. Equine blood polymorphonuclear leukocytes (PMN) were isolated by buffy coat and hypotonic lysis of residual erythrocytes. A highly reproducible method is described for measuring the uptake of opsonized latex microspheres by equine PMN using flowcytometry. The use of cytochalasin D allowed for differentiation of ingested from attached particles. The kinetics of phagocytosis in vitro is shown for different experimental conditions. We developed an assay for evaluation of phagocytic capacity of PMN which allows the assessment of drugs for their influence on phagocytosis in vivo as well as in vitro...
A comparison of two computer-automated semen analysis instruments for the evaluation of sperm motion characteristics in the stallion. Two commercially available computer-automate semen analysis instruments (CellSoft Automated Semen Analyzer and HTM-2000 Motion Analyzer) were compared for their ability to report similar results based on the analysis of pre-recorded video tapes of extended, motile stallion semen. The determinations of the percentage of motile cells by these instruments were more similar than the comparisons between subjective estimates and either instrument. However, mean values obtained from the same sample may still differ by as much as 30 percentage units between instruments. Instruments varied with regard ...
Molecular cloning of Ehrlichia risticii and development of a gene probe for the diagnosis of Potomac horse fever. A gene bank of Ehrlichia risticii was constructed in plasmid vector pUC13. Five clones representing discrete regions of the E. risticii genome were tested for their ability to hybridize specifically to E. risticii DNA. None of the clones cross-hybridized with Ehrlichia equi DNA, whereas four of these clones cross-hybridized with Ehrlichia canis and Ehrlichia sennetsu DNAs. However, one clone carrying a 1-kilobase HindIII fragment of E. risticii DNA failed to cross-react with the genomes of E. sennetsu, E. canis, and E. equi in dot blot hybridization assays. The sensitivity of this probe for th...
A contact method for the assessment of ultrasonic velocity and broadband attenuation in cortical and cancellous bone. A portable system using a direct contact for the measurement of ultrasonic velocity and broadband attenuation in bone is described (contact ultrasonic bone analyser, CUBA). Soft-tissue compensation is performed using an ultrasonic pulse-echo technique. CUBA has been successfully validated using reference materials, the precision of velocity and broadband attenuation measurements being typically 0.2% and 0.5% respectively. The clinical reproducibility has been assessed on the equine third metacarpal bone. The reproducibility of velocity measurement is typically 0.5% for cortical bone and 1% for...
Cloning and characterization of cDNAs encoding equine infectious anemia virus tat and putative Rev proteins. We isolated and characterized six cDNA clones from an equine infectious anemia virus-infected cell line that displays a Rev-defective phenotype. With the exception of one splice site in one of the clones, all six cDNAs exhibited the same splicing pattern and consisted of four exons. Exon 1 contained the 5' end of the genome; exon 2 contained the tat gene from mid-genome; exon 3 consisted of a small section of env, near the 5' end of the env gene; and exon 4 contained the putative rev open reading frame from the 3' end of the genome. The structures of the cDNAs predict a bicistronic message in ...
High-resolution study of the three-dimensional structure of horse heart metmyoglobin. The three-dimensional structure of horse heart metmyoglobin has been refined to a final R-factor of 15.5% for all observed data in the 6.0 to 1.9 A resolution range. The final model consists of 1242 non-hydrogen protein atoms, 154 water molecules and one sulfate ion. This structure has nearly ideal bonding and bond angle geometry. A Luzzati plot of the variation in R-factor with resolution yields an estimated mean co-ordinate error of 0.18 A. An extensive analysis of the pattern of hydrogen bonds formed in horse heart metmyoglobin has been completed. Over 80% of the polypeptide chain is involv...
Cryopreservation of equine mononuclear cells for immunological studies. A rapid and simple technique for the cryopreservation and recovery of equine mononuclear cells was developed. Buffy-coat leukocytes were frozen in autologous plasma containing 10% DMSO and mononuclear cells were recovered by gradient sedimentation using a standard Ficoll-Hypaque purification procedure. The total numbers of mononuclear cells recovered from cryopreserved samples were 94%-82% of those recovered from fresh blood samples. The functional capabilities of the mononuclear cells from cryopreserved buffy coat preparations were compared with those of mononuclear cells from fresh samples b...
