Sialic acids are a family of nine-carbon acidic sugars found at the terminal position of glycan chains on glycoproteins and glycolipids in horses. They are involved in various biological processes, including cellular communication, pathogen recognition, and modulation of the immune system. In equine health, sialic acids contribute to the structural integrity of cell membranes and influence interactions between cells and their environment. Alterations in sialic acid expression or structure can affect physiological functions and may be associated with disease states. This page compiles peer-reviewed research studies and scholarly articles that explore the distribution, function, and potential clinical implications of sialic acids in horses.
Spruit CM, Zhu X, Tomris I, Ríos-Carrasco M, Han AX, Broszeit F, van der Woude R, Bouwman KM, Luu MMT, Matsuno K, Sakoda Y, Russell CA, Wilson IA....Influenza A viruses (IAV) initiate infection by binding to glycans with terminal sialic acids on the cell surface. Hosts of IAV variably express two major forms of sialic acid, -acetylneuraminic acid (NeuAc) and -glycolylneuraminic acid (NeuGc). NeuGc is produced in most mammals, including horses and pigs, but is absent in humans, ferrets, and birds. The only known naturally occurring IAV that exclusively bind NeuGc are extinct highly pathogenic equine H7N7 viruses. We determined the crystal structure of a representative equine H7 hemagglutinin (HA) in complex with NeuGc and observed high simi...
Parillo F, Rossi G, Busoni V, Magi GE, Verini Supplizi A.The aim of this study was to investigate the carbohydrate composition of mucosubstances in the equine guttural pouches using conventional histochemical tests in conjunction with glycolytic digestion to degrade different classes of glycosoaminoglycans. In the goblet cells, the mucopolysaccharides contained chondroitin sulfate B, heparin, heparan sulfate and sialic acid residues. The acinar cells also expressed these substances (except for heparin), whereas the ductal cells produced chondroitin sulfate B and sialic acid. Neutral sugars were also found in each cell type. The diversity of the glyc...
Yasui T, Tsukise A, Fukui K, Kuwahara Y, Meyer W.The distribution of complex glycoconjugates and antimicrobial substances in the ceruminous glands of the horse (Equus przewalskii f. dom., type: pony) was studied using carbohydrate histochemical and immunohistochemical methods. The epithelial cells and luminal secretion of these glands exhibited considerable amounts of glycoconjugates with various saccharide residues, such as alpha-D-mannose, alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine and sialic acid, including O-acetylated sialic acid. Several sugars (alpha-D-mannose, alpha-L-fucose, and beta-D-galactose) were also detecta...
Nakamura T, Amikawa S, Harada T, Saito T, Arai I, Urashima T.The colostrum of horses (thoroughbreds) was extracted and fractionated to yield Gal(beta1-4)GlcNAcalpha1-phosphate, which has not previously been detected in any mammalian milk or colostrum, as well as Neu5Ac(alpha2-3)Gal(beta1-4)Glc. The structures of these saccharides were established by NMR spectroscopy and MALDI-TOF mass spectrometry.
Verini-Supplizi A, Stradaioli G, Fagioli O, Parillo F.The testes of prepubertal and adult horses were investigated using 10 horseradish peroxidase conjugated lectins combined with sialidase digestion and potassium hydroxide treatment, to localise the oligosaccharide sequences of glycoconjugates during spermatid maturation. In adult animals, the lectins showed a variable affinity for spermatids and Sertoli cell apical extensions. Soybean agglutinin (SBA), peanut agglutinin (PNA), Ricinus communis agglutinin (RCA-I) and wheat germ agglutinin (WGA) bound to the acrosomal structures of spermatids, whereas Griffonia simplicifolia agglutinin (GSA-II) l...
Saxena A, Ashani Y, Raveh L, Stevenson D, Patel T, Doctor BP.To understand the role of glycosylation in the circulation of cholinesterases, we compared the mean residence time of five tissue-derived and two recombinant cholinesterases (injected intravenously in mice) with their oligosaccharide profiles. Monosaccharide composition analysis revealed differences in the total carbohydrate, galactose, and sialic acid contents. The molar ratio of sialic acid to galactose residues on tetrameric human serum butyrylcholinesterase, recombinant human butyrylcholinesterase, and recombinant mouse acetylcholinesterase was found to be approximately 1.0. For Torpedo ca...
Saxena A, Raveh L, Ashani Y, Doctor BP.Cholinesterases are serine hydrolases that can potentially be used as pretreatment drugs for organophosphate toxicity, as drugs to alleviate succinylcholine-induced apnea, and as detoxification agents for environmental toxins such as heroin and cocaine. The successful application of serum-derived cholinesterases as bioscavengers stems from their relatively long residence time in the circulation. To better understand the relationship between carbohydrate structure and the stability of cholinesterases in circulation, we determined the monosaccharide composition, the distribution of various oligo...
Irvine CH.Isoelectric focussing of crude extracts of equine pituitaries was used to obtain fractions containing FSH and LH. By comparison with FSH, LH was distributed over a similar but wider pH range indicating more marked polymorphism as determined from their isoelectric point (pI). Molecules with more sialic acid showed lower pI consistent with the concept that sialic acid is the major factor in determining pI and polymorphism in FSH and LH. Appropriate fractions were labelled with 125I, purified further and used in kinetic studies. FSH and LH molecules of similar pI had similar kinetics; however, LH...
Hueso P, Rocha M.The present paper deals with a comparative study on six methods for isolation of peripheral blood lymphocytes from various mammalian sources: Bos taurus L. (adult cow), Equus caballus L. (adult horse), Equus asinus L. (adult and young donkeys) and Sus scropha L. (adult pig). The following systems were used: a) Filtration through sand columns (a modification of Blaszczyszyn's method); b) Sodium metrizoate and "Ficoll 400" c) "Lymphoprep"; d) "Urovison" and dextran T150 (a modification of GILI et al.'s method); e) "Urografin" and dextran T150; f) "Ficoll-Paque". The final preparation of lymphocy...
Glöckner WM, Newman RA, Dahr W, Uhlenbruck G.Phenol extraction of horse, sheep, cow, pig and human erythrocyte membranes and human milk fat globule membranes gave glycoprotein fractions, all of which were shown by gas chromatography to contain the reduced disaccharide beta-D-galactosyl (1-3)-N-acetyl-D-galactosaminital after treatment with alkaline borohydride. Cow and pig erythrocyte membrane glycoproteins were found however to contain much lower amounts than the erythrocyte membrane glycoproteins of the other species tested. After gel filtration, a tetrasaccharide was isolated from horse and sheep glycoproteins containing the disacchar...
Fujita S, Cleve H.The major glycoproteins of horse and swine erythrocyte membranes were isolated and examined chemically and immunologically. The major glycoprotein of horse erythrocyte membranes had a molecular weight of 33 000 and consisted of 46.2% protein and 53.8% carbohydrate, of which 9.4% was hexose, 10.1% hexosamine and 33.7% sialic acid. This glycoprotein was associated with activity for the infectious mononucleosis heterophile antigen. There were two different major glycoproteins in swine erythrocyte membranes. One major glycoprotein had a molecular weight of 46 200 and consisted of 34.2% protein and...
Saxena A, Ashani Y, Raveh L, Stevenson D, Patel T, Doctor BP.To understand the role of glycosylation in the circulation of cholinesterases, we compared the mean residence time of five tissue-derived and two recombinant cholinesterases (injected intravenously in mice) with their oligosaccharide profiles. Monosaccharide composition analysis revealed differences in the total carbohydrate, galactose, and sialic acid contents. The molar ratio of sialic acid to galactose residues on tetrameric human serum butyrylcholinesterase, recombinant human butyrylcholinesterase, and recombinant mouse acetylcholinesterase was found to be approximately 1.0. For Torpedo ca...
Saxena A, Raveh L, Ashani Y, Doctor BP.Cholinesterases are serine hydrolases that can potentially be used as pretreatment drugs for organophosphate toxicity, as drugs to alleviate succinylcholine-induced apnea, and as detoxification agents for environmental toxins such as heroin and cocaine. The successful application of serum-derived cholinesterases as bioscavengers stems from their relatively long residence time in the circulation. To better understand the relationship between carbohydrate structure and the stability of cholinesterases in circulation, we determined the monosaccharide composition, the distribution of various oligo...
Glöckner WM, Newman RA, Dahr W, Uhlenbruck G.Phenol extraction of horse, sheep, cow, pig and human erythrocyte membranes and human milk fat globule membranes gave glycoprotein fractions, all of which were shown by gas chromatography to contain the reduced disaccharide beta-D-galactosyl (1-3)-N-acetyl-D-galactosaminital after treatment with alkaline borohydride. Cow and pig erythrocyte membrane glycoproteins were found however to contain much lower amounts than the erythrocyte membrane glycoproteins of the other species tested. After gel filtration, a tetrasaccharide was isolated from horse and sheep glycoproteins containing the disacchar...
Nakamura T, Amikawa S, Harada T, Saito T, Arai I, Urashima T.The colostrum of horses (thoroughbreds) was extracted and fractionated to yield Gal(beta1-4)GlcNAcalpha1-phosphate, which has not previously been detected in any mammalian milk or colostrum, as well as Neu5Ac(alpha2-3)Gal(beta1-4)Glc. The structures of these saccharides were established by NMR spectroscopy and MALDI-TOF mass spectrometry.
Yasui T, Tsukise A, Fukui K, Kuwahara Y, Meyer W.The distribution of complex glycoconjugates and antimicrobial substances in the ceruminous glands of the horse (Equus przewalskii f. dom., type: pony) was studied using carbohydrate histochemical and immunohistochemical methods. The epithelial cells and luminal secretion of these glands exhibited considerable amounts of glycoconjugates with various saccharide residues, such as alpha-D-mannose, alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine and sialic acid, including O-acetylated sialic acid. Several sugars (alpha-D-mannose, alpha-L-fucose, and beta-D-galactose) were also detecta...
Spruit CM, Zhu X, Tomris I, Ríos-Carrasco M, Han AX, Broszeit F, van der Woude R, Bouwman KM, Luu MMT, Matsuno K, Sakoda Y, Russell CA, Wilson IA....Influenza A viruses (IAV) initiate infection by binding to glycans with terminal sialic acids on the cell surface. Hosts of IAV variably express two major forms of sialic acid, -acetylneuraminic acid (NeuAc) and -glycolylneuraminic acid (NeuGc). NeuGc is produced in most mammals, including horses and pigs, but is absent in humans, ferrets, and birds. The only known naturally occurring IAV that exclusively bind NeuGc are extinct highly pathogenic equine H7N7 viruses. We determined the crystal structure of a representative equine H7 hemagglutinin (HA) in complex with NeuGc and observed high simi...
Verini-Supplizi A, Stradaioli G, Fagioli O, Parillo F.The testes of prepubertal and adult horses were investigated using 10 horseradish peroxidase conjugated lectins combined with sialidase digestion and potassium hydroxide treatment, to localise the oligosaccharide sequences of glycoconjugates during spermatid maturation. In adult animals, the lectins showed a variable affinity for spermatids and Sertoli cell apical extensions. Soybean agglutinin (SBA), peanut agglutinin (PNA), Ricinus communis agglutinin (RCA-I) and wheat germ agglutinin (WGA) bound to the acrosomal structures of spermatids, whereas Griffonia simplicifolia agglutinin (GSA-II) l...
Fujita S, Cleve H.The major glycoproteins of horse and swine erythrocyte membranes were isolated and examined chemically and immunologically. The major glycoprotein of horse erythrocyte membranes had a molecular weight of 33 000 and consisted of 46.2% protein and 53.8% carbohydrate, of which 9.4% was hexose, 10.1% hexosamine and 33.7% sialic acid. This glycoprotein was associated with activity for the infectious mononucleosis heterophile antigen. There were two different major glycoproteins in swine erythrocyte membranes. One major glycoprotein had a molecular weight of 46 200 and consisted of 34.2% protein and...
Hueso P, Rocha M.The present paper deals with a comparative study on six methods for isolation of peripheral blood lymphocytes from various mammalian sources: Bos taurus L. (adult cow), Equus caballus L. (adult horse), Equus asinus L. (adult and young donkeys) and Sus scropha L. (adult pig). The following systems were used: a) Filtration through sand columns (a modification of Blaszczyszyn's method); b) Sodium metrizoate and "Ficoll 400" c) "Lymphoprep"; d) "Urovison" and dextran T150 (a modification of GILI et al.'s method); e) "Urografin" and dextran T150; f) "Ficoll-Paque". The final preparation of lymphocy...
Irvine CH.Isoelectric focussing of crude extracts of equine pituitaries was used to obtain fractions containing FSH and LH. By comparison with FSH, LH was distributed over a similar but wider pH range indicating more marked polymorphism as determined from their isoelectric point (pI). Molecules with more sialic acid showed lower pI consistent with the concept that sialic acid is the major factor in determining pI and polymorphism in FSH and LH. Appropriate fractions were labelled with 125I, purified further and used in kinetic studies. FSH and LH molecules of similar pI had similar kinetics; however, LH...
Parillo F, Rossi G, Busoni V, Magi GE, Verini Supplizi A.The aim of this study was to investigate the carbohydrate composition of mucosubstances in the equine guttural pouches using conventional histochemical tests in conjunction with glycolytic digestion to degrade different classes of glycosoaminoglycans. In the goblet cells, the mucopolysaccharides contained chondroitin sulfate B, heparin, heparan sulfate and sialic acid residues. The acinar cells also expressed these substances (except for heparin), whereas the ductal cells produced chondroitin sulfate B and sialic acid. Neutral sugars were also found in each cell type. The diversity of the glyc...
