Omneity® Pellets
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Topic:Protein
Proteins are essential macromolecules that play diverse roles in the physiology and health of horses. They are composed of amino acids and are involved in various biological processes, including tissue growth, repair, and the synthesis of enzymes and hormones. Dietary proteins are a key component of equine nutrition, influencing muscle development, immune function, and overall performance. Horses require a balanced intake of essential amino acids, which must be obtained through their diet, as they cannot be synthesized endogenously. This page compiles peer-reviewed research studies and scholarly articles that explore the types, functions, and dietary requirements of proteins in horses, as well as their impact on equine health and performance.
A possible role for the covalent heme-protein linkage in cytochrome c revealed via comparison of N-acetylmicroperoxidase-8 and a synthetic, monohistidine-coordinated heme peptide. N-Acetylmicroperoxidase-8 (1) contains heme and residues 14-21 of horse mitochondrial cytochrome c (cyt c). The two thioether bonds linking protein to heme in cyt c are present in 1, and the native axial ligand His-18 remains coordinated to iron. As an approach to probing structural or functional roles played by the double covalent heme-protein linkage in cyt c, we have initiated a study in which the properties of 1 are compared with those of a synthetic mono-His coordinated heme peptide containing a single covalent linkage (2). One consequence of the greater conformational restriction imposed...
Peptide transport activity of the transporter associated with antigen processing (TAP) is inhibited by an early protein of equine herpesvirus-1. Equine herpesvirus-1 (EHV-1) downregulates surface expression of major histocompatibility complex (MHC) class I molecules on infected cells. The objective of this study was to investigate whether EHV-1 interferes with peptide translocation by the transporter associated with antigen processing (TAP) and to identify the proteins responsible. Using an in vitro transport assay, we showed that EHV-1 inhibited transport of peptides by TAP as early as 2 h post-infection (p.i). Complete shutdown of peptide transport was observed by 8 h p.i. Furthermore, pulse-chase experiments revealed that maturation...
The analytical approach to the nature of lipofuscin (age pigment). Analytical studies of three lipopigments show that much can be achieved. Lipopigment from ovine ceroid-lipofuscinosis is composed of discrete protein and lipid molecules in orderly arrays and lipid peroxidation is not involved in its formation. Subunit c of mitochondrial ATP synthase accounts for approximately 50% of accumulated material and is specific to the disease process in this and other forms of the disease. Lipofuscin from bovine heart was mostly soluble and also contained discrete proteins, lipids and metals. Equine thyroid lipofuscin was less soluble but also had a relatively high pr...
Nutrition for critical gastrointestinal illness: feeding horses with diarrhea or colic. Horses with GI diseases such as colic and diarrhea are often intolerant of adequate enteral nutrition. Nutritional intervention should be an early part of therapeutic management in such cases. Protein and energy malnutrition in critically ill horses can have deleterious effects, including poor wound or incisional healing, reduced immunity, and weight loss. Early enteral or parenteral support should be provided to supply resting DE requirements in the equine ICU.
Postnatal development of hepatic oxidative, hydrolytic and conjugative drug-metabolizing enzymes in female horses. Little is known about the effects of aging on the hepatic drug metabolizing capacity of horses despite the relatively long lifespan characterizing this species. A wide array of cytochrome P450 (CYP)-dependent monooxygenases, carboxylesterases and transferases were assayed in liver microsomes from 50 female horses in an age range between less than 1 year to over 12 years. Rather unexpectedly, both the CYP content and the activity of NADPH cytochrome c reductase rose as a function of age. Accordingly, a general increasing trend was recorded in the rate of the in vitro metabolism of the substrate...
Fibronectin fragments cause release and degradation of collagen-binding molecules from equine explant cultures. Previous experiments have shown that addition of fragmented fibronectin can induce cartilage chondrolysis. In this study we investigated the fate of the collagen- and cell-binding molecules Cartilage oligomeric matrix protein (COMP) and chondroadherin. Methods: Equine articular cartilage explants were stimulated with the C-terminal and the N-terminal heparin-binding fragments of fibronectin respectively, and the conditioned media were analysed by both quantitative (ELISA) and qualitative (mass spectrometry, Western blots) methods. Results: Both COMP and chondroadherin were released in a dose-d...
Immunohistochemical identification and fiber type specific localization of protein kinase C isoforms in equine skeletal muscle. To investigate whether protein kinase C (PKC) isoforms are expressed in equine skeletal muscle and determine their distribution in various types of fibers by use of immunofluorescence microscopy. Methods: 5 healthy adult Dutch Warmblood horses. Methods: In each horse, 2 biopsy specimens were obtained from the vastus lateralis muscle. Cryosections of equine muscle were stained with PKC isoform (alpha, beta1, beta2, delta, epsilon, or zeta)-specific polyclonal antibodies and examined by use of a fluorescence microscope. Homogenized muscle samples were evaluated via western blot analysis. Results...
Nucleotide sequence of equine erythropoietin and characterization of region-specific antibodies. To determine the full-length complementary DNA (cDNA) sequence of equine erythropoietin (EPO) and to develop region-specific antibodies to differentiate equine EPO (eEPO) and human EPO (hEPO). Methods: RNA and lysate extracted from renal tissues of an adult Thoroughbred. Methods: Full-length cDNA was determined by use of a reverse transcriptase-polymerase chain reaction assay and a rapid amplification of cDNA ends method. The deduced amino acid sequence was compared with sequences of EPO reported for other species. Furthermore, 4 synthetic peptides were designed in 2 distinctive parts of the e...
Interaction of fibronectin type II proteins with membranes: the stallion seminal plasma protein SP-1/2. Seminal plasma of mammalians contains, among others, proteins that are characterized by the fibronectin (Fn) type II module. Our knowledge about the structure and the physiological function of seminal Fn type II proteins mainly originates from studies on PDC-109, the bovine representative of this protein family. The present work focuses on the equine protein SP-1/2 (also named HSP-1/2) with particular emphasis on its interaction with lipid membranes by employing the intrinsic protein fluorescence and a number of spin-labeled and fluorescent lipid analogues. The results indicate that the intera...
Molecular cloning of a Babesia caballi gene encoding the 134-kilodalton protein and evaluation of its diagnostic potential in an enzyme-linked immunosorbent assay. A Babesia caballi gene encoding the 134-kDa (BC134) protein was immunoscreened with B. caballi-infected horse serum. An enzyme-linked immunosorbent assay (ELISA) using recombinant BC134 protein could effectively differentiate B. caballi-infected horse sera from Babesia equi-infected or noninfected control horse sera. These results suggest that the recombinant BC134 protein is a potential diagnostic antigen in the detection of B. caballi infection.
Late domain-dependent inhibition of equine infectious anemia virus budding. The Gag proteins of a number of different retroviruses contain late or L domains that promote the release of virions from the plasma membrane. Three types of L domains have been identified to date: Pro-Thr-Ala-Pro (PTAP), Pro-Pro-X-Tyr, and Tyr-Pro-Asp-Leu. It has previously been demonstrated that overexpression of the N-terminal, E2-like domain of the endosomal sorting factor TSG101 (TSG-5') inhibits human immunodeficiency virus type 1 (HIV-1) release but does not affect the release of the PPPY-containing retrovirus murine leukemia virus (MLV), whereas overexpression of the C-terminal portion...
Effects of exercise and glucose administration on content of insulin-sensitive glucose transporter in equine skeletal muscle. To characterize insulin-sensitive glucose-transporter (GLUT-4) protein in equine tissues and determine effects of exercise and glucose administration on content of GLUT-4 protein in equine skeletal muscle. Methods: Tissue samples from 9 horses. Methods: Western blot analyses were performed on crude membrane preparations of equine tissues to characterize GLUT-4. In a crossover, randomized study, horses were strenuously exercised for 3 consecutive days and then administered 13.5% glucose or isotonic saline (0.9% NaCl; control) solution, i.v., at similar infusion rates for 12.1 hours. Samples wer...
Platelets enhance endotoxin-induced monocyte tissue factor (TF) activity in the horse. Endotoxaemia is the leading cause of death in horses. Disseminated intravascular coagulation (DIG), stimulated by induced monocyte proteins, is a prominent feature. Monocyte-platelet cellular interactions are central to the vascular dysfunction produced by circulating endotoxin and are implicated in many thrombotic diseases in the horse. This study reports that endotoxin (0.01-10 microg ml(-1)) and blood platelets (2.5 x 10(7) - 1 x 10(8) ml(-1)) are potent inducers of expression and activity of monocyte tissue factor (TF), the primary activator of the blood coagulation protease cascade. The c...
Intra- and intermolecular disulfide bonds of the GP2b glycoprotein of equine arteritis virus: relevance for virus assembly and infectivity. Equine arteritis virus (EAV) is an enveloped, positive-strand RNA virus belonging to the family Arteriviridae of the order NIDOVIRALES: EAV virions contain six different envelope proteins. The glycoprotein GP(5) (previously named G(L)) and the unglycosylated membrane protein M are the major envelope proteins, while the glycoproteins GP(2b) (previously named G(S)), GP(3), and GP(4) are minor structural proteins. The unglycosylated small hydrophobic envelope protein E is present in virus particles in intermediate molar amounts compared to the other transmembrane proteins. The GP(5) and M protein...
The amino acid sequence of protein AA from a burro (Equus asinus). The primary structure of amyloid fibril protein AA of a burro has been determined by Edman degradation. The 80 amino acid residue long protein shows strong resemblance to that of other mammalian AA-proteins and differs from equine protein AA at 5 positions: Burro/horse positions 20 (Q/N), 44 (R,Q, K/K,Q), 59 (G,L/G,A), 61 (Q/E) and 65 (N/R).
Dexamethasone for treatment of multisystemic eosinophilic epitheliotropic disease in a horse. A 4-year-old Paint mare was examined because of respiratory tract infection, dermatitis, and weight loss of 2 months' duration. Initial examination revealed generalized pruritic dermatitis, ocular and nasal discharges, and stranguria. Laboratory abnormalities included leukopenia and hypoalbuminemia. Further examination of the respiratory tract revealed grade III of IV pharyngitis and pyogranulomatous pneumonia. Endoscopic examination of the bladder revealed a prolific mass at the junction of the bladder and urethra. Hypoproteinemia was suspected to be caused by protein-losing enteropathy. On h...
Effect of moderate exercise immediately followed by induced hyperglycemia on gene expression and content of the glucose transporter-4 protein in skeletal muscles of horses. To determine the effect of a single bout of exercise and increased substrate availability after exercise on gene expression and content of the glucose transporter-4 (GLUT-4) protein in equine skeletal muscle. Methods: 6 healthy adult Thoroughbreds. Methods: The study was designed in a balanced, randomized, 3-way crossover fashion. During 2 trials, horses were exercised at 45% of their maximal rate of oxygen consumption for 60 minutes after which 1 group received water (10 mL/kg), and the other group received glucose (2 g/kg, 20% solution) by nasogastric intubation. During 1 trial, horses stood...
Novel purification method for mammalian seminal plasma phospholipid-binding proteins reveals the presence of a novel member of this family of protein in stallion seminal fluid. A family of bull seminal plasma (BSP) phospholipid-binding proteins (BSP proteins), potentiate heparin- and HDL-induced capacitation. The homologous proteins have been purified from stallion and boar seminal plasma, and detected in low concentrations in other mammalian seminal plasma. In this study, we developed a new isolation method for mammalian seminal plasma choline phospholipid-binding proteins wherein they are present in low concentrations. The method is based on the interaction of this family of proteins with egg yolk low-density lipoprotein fraction (LDF). In order to demonstrate the ...
Rhodococcus equi secreted antigens are immunogenic and stimulate a type 1 recall response in the lungs of horses immune to R. equi infection. Rhodococcus equi is an opportunistic pathogen in immunocompromised humans and an important primary pathogen in young horses. Although R. equi infection can produce life-threatening pyogranulomatous pneumonia, most foals develop a protective immune response that lasts throughout life. The antigen targets of this protective response are currently unknown; however, Mycobacterium tuberculosis is a closely related intracellular pathogen and provides a model system. Based on previous studies of M. tuberculosis protective antigens released into culture filtrate supernatant (CFS), a bacterial growth s...
Expression of key prostaglandin synthases in equine endometrium during late diestrus and early pregnancy. Luteolysis in domestic species is mediated by the release of luteolytic pulses of prostaglandin (PG) F(2alpha) by the uterus at the end of diestrus, which must be suppressed by the conceptus to permit maternal recognition of pregnancy. In many species, including the horse, both the conceptus and the endometrium also synthesize PGE(2), which may antagonize PGF(2alpha) by playing a luteotropic and/or antiluteolytic role. While the release of PGE(2) and PGF(2alpha) by the equine endometrium in late diestrus and early pregnancy has been previously studied, the underlying prostaglandin synthase gen...
Abnormal synaptic protein expression in two Arabian horses with equine degenerative myeloencephalopathy. Numerous swollen neurons and multiple dystrophic axons were observed in the gracillis and cuneatus nuclei of two male Arabian horses, aged six and 12 months of age, with equine degenerative myeloencephalopathy. Swollen neurons and dystrophic axons showed synaptophysin, synaptosomal-associated protein of 25 kDa, syntaxin-1 and alpha-synuclein immunoreactivity. Moreover, dystrophic axons were strongly immunopositive against the ubiquitin protein and against the anti-phosphorylated 200 kDa neurofilament protein. Abnormal expression of integral synaptic vesicle, synaptic vesicle-associated presyna...
Protein kinase C (PKC) isotype profile in eosinophils from ponies with sweet itch and role in histamine-induced eosinophil activation. Eosinophils have been implicated in the pathogenesis of the seasonal equine allergic skin disease, sweet itch. Protein kinase C (PKC) is involved in regulating eosinophil function and antigen challenge has been reported to alter PKC isotype expression in blood eosinophils from allergic human subjects. Here we have compared the pattern of PKC isotype expression in eosinophils from sweet itch ponies with that in cells from normal ponies both during the active and inactive phases of the disease. A role for PKC in histamine-induced eosinophil activation was also investigated. Conventional PKCs alp...
Different CREM-isoform gene expression between equine and human normal and impaired spermatogenesis. Histone-to-protamine exchange causes chromatin condensation ceasing gene expression in elongating spermatids. Gene expression of protamines is regulated by the transcription factor cAMP-responsive element modulator (CREM). Altered CREM expression results in male infertility, as shown by CREM-knock-out mice being sterile due to round spermatid maturation arrest and patients exhibiting round spermatid maturation arrest revealing a lack or substantial reduction of both CREM-mRNA and CREM-protein. Similar defects in histone-to-protamine exchange have been suggested in infertile stallions exhibitin...
Novel plasmid-borne gene qacJ mediates resistance to quaternary ammonium compounds in equine Staphylococcus aureus, Staphylococcus simulans, and Staphylococcus intermedius. We identified a novel plasmid-borne gene (designated qacJ) encoding resistance to quaternary ammonium compounds (QACs) in three staphylococcal species associated with chronic infections in four horses. qacJ was located on a 2,650-bp plasmid (designated pNVH01), a new member of the pC194 family of rolling-circle replication plasmids. The 107-amino-acid protein, QacJ, showed similarities to known proteins of the small multidrug resistance family: Smr/QacC (72.5%), QacG (82.6%), and QacH (73.4%). The benzalkonium chloride MIC for a qacJ-containing recombinant was higher than those for otherwise i...
Evaluation of various compounds to inhibit activity of matrix metalloproteinases in the tear film of horses with ulcerative keratitis. To examine in vitro effects of various antiproteolytic compounds on activity of matrix metalloproteinase (MMP)-2 and -9 in the tear film of horses with active corneal ulcers. Methods: Samples of tear film obtained from the eyes of 34 horses with active ulcerative keratitis. Methods: Horses were sedated, and tear samples were collected from the lower fornix of 34 ulcerated eyes by use of capillary tubes. The protease inhibitors 0.2% EDTA, 0.1% doxycycline, 10% N-acetylcysteine (NAC), 0.1% solution of a modified dipeptide that contains hydroxamic acid (ie, ilomostat), 0.1% alpha1-proteinase inhi...
Purification and analyses of the specificity of two putative diagnostic antigens for larval cyathostomin infection in horses. Cyathostomins are important equine gastrointestinal parasites. Mass emergence of mucosal stage larvae causes a potentially fatal colitis. Mucosal stages are undetectable non-invasively. An assay that would estimate mucosal larval stage infection would greatly assist in treatment, control and prognosis. Previously, we identified two putative diagnostic antigens (20 and 25 kDa) in somatic larval preparations. Here, we describe their purification and antigen-specific IgG(T) responses to them. Western blots confirmed the purity of the antigens and showed that epitopes in the 20 kDa complex were sp...
Cloning, expression and biological activity of equine interleukin (IL)-5. The cytokine, interleukin (IL)-5 stimulates eosinophil differentiation, activation and survival and can prime these cells, increasing the response to other mediators. In view of its many effects on eosinophils, IL-5 has been implicated in the pathogenesis of allergic disease in man. Here we report the cloning of equine IL-5 and expression of the recombinant protein by transfection of Chinese hamster ovary (CHO) cells. The cloned cDNA sequence consisted of 405 nucleotides and encoded a protein of 135 amino acids. There is >85% identity with feline, bovine, ovine, canine, and human IL-5 sequence...
[Fluorescence spectroscopic study of interaction between Fe-protoporphyrin in myoglobin and Cu(II) ions]. In this paper, the interaction between Cu(II) ions and Fe-protoporphyrin in horse-heart myoglobin (FePP-Mb) was studied. As a result, some of the Fe(II) ions in FePP-Mb were found to be replaced by Cu(II) ions forming CuPP-Mb, by adding Cu(II) ions into the myoglobin solution. The interaction became stronger when adding more Cu(II) ions into the myoglobin solution. By studying the metal ions' interaction with myoglobin proteins as macromolecules and discussing the interaction mechanism, this work provides a theoretical basis for the further study of hazardous metal ions' interaction with the h...
A pH-dependent aquomet-to-hemichrome transition in crystalline horse methemoglobin. In 1947, Perutz and co-workers reported that crystalline horse methemoglobin undergoes a large lattice transition as the pH is decreased from 7.1 to 5.4. We have determined the pH 7.1 and 5.4 crystal structures of horse methemoglobin at 1.6 and 2.1 A resolution, respectively, and find that this lattice transition involves a 23 A translation of adjacent hemoglobin tetramers as well as changes in alpha heme ligation and the tertiary structure of the alpha subunits. Specifically, when the pH is lowered from 7.1 to 5.4, the Fe(3+) alpha heme groups (but not the beta heme groups) are converted from...
Identification of variations in SzP proteins of Streptococcus equi subspecies zooepidemicus and the relationship between protein variants and clinical signs of infection in horses. To determine whether previously unidentified variations of the SzP protein of Streptococcus equi subsp zooepidemicus were present in horses with various clinical signs of infection and whether any relationship could be identified between SzP protein variants and naturally occurring clinical conditions. Methods: 23 isolates of S equi subsp zooepidemicus were recovered from specimens of horses with various clinical conditions and used as a representative population of isolates for evaluation of different SzP protein variants. Methods: Genetic heterogeneity of the isolates was demonstrated by rep...
