Enzymes are biological catalysts that facilitate biochemical reactions in horses by lowering the activation energy required for these processes. They are involved in various physiological functions, including digestion, metabolism, and cellular repair. Common enzymes in equine biology include amylase, lipase, and lactate dehydrogenase, each playing a specific role in the breakdown of nutrients and energy production. The activity and concentration of these enzymes can vary in response to different physiological and pathological conditions, serving as potential indicators in veterinary diagnostics. This page compiles peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical implications of enzymes in equine health.
Bindi F, de Marchi L, Elias-Cortajarena A, Sala G, Vitale V, Spadari A, Rinnovati R, Bonelli F, Sgorbini M.Colic is a major cause of morbidity and mortality in horses, with oxidative stress implicated in its pathophysiology. Objective: Evaluate biomarkers (BIOs) of oxidative stress and antioxidant defense in healthy horses and those with non-strangulating colic (NSC) and strangulating colic (SC) and assess correlations with survival. Methods: Seventy-one adult horses: 10 healthy and 61 colic-affected (42 NSC, 19 SC) admitted to 3 veterinary teaching hospitals. Methods: Prospective, multicenter cohort study. Blood samples were collected at admission (T0) and up to 96 h post-admission. Biomarkers me...
Böckmann S, Trzebiatowski L, Georgiev P, Büttner K, Wehrend A.Immunoglobulins ingested via colostrum must remain intact to be absorbed by the neonate. Equine colostrum contains antitrypsin activity, which likely protects these proteins from proteolysis in the gastrointestinal tract. Objective: To quantify antitrypsin activity in equine colostrum and milk, describe its temporal changes during the first five days after parturition, compare actitvity between left and right mammary glands, evaluate differences between nulliparous and pluriparous mares, and examine associations with immunoglobulin G (IgG) concentrations and mare age. Methods: This retrospecti...
Bindi F, Cingottini D, Sorvillo B, Sala G, De Marchi L, Monni G, Celardo S, Bonelli F, Sgorbini M.During the perinatal period, neonates experience a sudden increase in oxygen exposure, predisposing them to oxidative stress. Objective: This prospective, in vivo study aimed to evaluate biomarkers of oxidative stress and antioxidant defence in healthy neonatal foals during the first 48 hours of life. Methods: Ten Standardbred foals were enrolled. Blood samples were collected at birth, 24 hours, and 48 hours after birth and analyzed for biomarkers using spectrophotometry assays. Statistical analysis was performed using non-parametric tests and linear regression. Results: The results revealed s...
He H, Han L, Ni W, Yu J, Liu K, Li W, Li C, Hu S, Li C, Li X.Herbivores represent crucial subjects for mining highly efficient carbohydrate-active enzymes (CAZymes) from gut microbiomes. Here, we analyzed 12,763 metagenome-assembled genomes (MAGs) from the horse gut, revealing that its microbial community as a rich reservoir of CAZymes diversity, with 5,204,848 glycoside hydrolases (GHs) and 4,596,191 glycosyl transferases (GTs) identified. Our findings demonstrate that Bacteroidota (5,479,287 CAZymes) and Bacillota_A (2,987,684 CAZymes) serve as the primary functional phyla for plant polysaccharide degradation. A total of 17,250 polysaccharide utilizat...
Baird JD, Arroyo LG, Lumsden JH.The objective of this study was to determine the effect of either oral supplementation of sodium selenite and alpha-tocopherol or intramuscular administration of a commercial preparation of selenium (Se) and vitamin E to Standardbred broodmares with low (21.0 ± 18.1 IU/g Hb) whole blood glutathione peroxidase (GPx) activity. Ten mares received 3 weekly intramuscular (IM) doses, whereas 9 mares were orally supplemented daily for 10 wk. Blood samples were collected jugular venipuncture and the whole blood GPx activity was measured at each sampling time for the 32-week period. Both oral and int...
Rump-Dierig I, Giers J, Frenzel C, Stöckle S, Gehlen H.This study examines seasonal changes in muscle and heart parameters in eventing horses over the course of a competition season. Blood levels of the enzymes creatine kinase (CK) and aspartate aminotransferase (AST) as well as the heart muscle-specific concentration of cardiac troponin I (cTnI) were measured before (pre), 30 min (p30) and 24 h (p24) after competitions. Creatine kinase (CK: median pre-competition = 175 U/L, 30 min post = 221 U/L, 24 h post = 140 U/L), aspartate aminotransferase (AST: pre = 319 U/L, p30 = 335 U/L, p24 = 333 U/L), and cardiac troponin I concentration (cTnI: pre = 0...
Cloteau C, Delcourt V, Loup B, Chabot B, Pescher M, Susdorf E, Kaabia Z, Garcia P, Popot MA, Le Bizec B, Dervilly G, Bailly-Chouriberry L.Biomarker identification by mass spectrometry represents a key step in the workflow of nontargeted metabolomic studies. Given the complexity of the data, this step, which must be carried out by a trained specialist, is time-consuming, and the biomarkers discovered are not always identified. While this stage is not an obstacle to the development of new screening and classification tools, it is nonetheless crucial to a better understanding of the results obtained. For this reason, the aim of this study was to perform structural elucidation of candidate biomarkers, which had previously been displ...
Sugimoto K, Nakamura J, Deng D, Hirano E.Indoxyl sulfate (IS) is a dietary metabolite of tryptophan that is produced in the liver. It is a uremic toxin that facilitates the progression of chronic kidney disease (CKD). We previously observed that equine placental extract (ePE) inhibited IS synthesis in an inhibition assay using the liver S9 fraction. Unassigned: This study was designed to investigate the effects of ePE on adenine-induced renal failure in mice at the histological and molecular levels to understand the mechanism of action of ePE. Unassigned: We assessed this effect through biochemical and histological analyses using a...
An N, Yang J, Zhao X, Basak P, Zhang Y, Suo H, Song J.High hydrostatic pressure (HHP) can modify protein structures to enhance functional properties, yet its effects on mare milk casein are unknown. This study investigated how HHP modifies mare milk casein's physicochemical, structural, and functional characteristics at pH 7 and 9. The results showed that HHP increased solubility, reduced turbidity, and altered particle size and surface charge. Structural analysis revealed conformational changes, including decreased β-sheet content (pH 7) and increased hydrophobic exposure. Functionally, at pH 7, HHP enhanced foaming and water-holding capacit...
Pires MJ, Cotovio M, Queiroga F, Pires CA, Silvestre-Ferreira AC.To date, serum biochemical analytes reference intervals (RIs) in Lusitano horses have not been studied. This study aimed to establish the RIs for biochemical analytes following the American Society of Veterinary Clinical Pathology guidelines and to compare them with the general equine population's RIs. Blood samples were collected from 76 clinically healthy adult Lusitano horses, and RIs of 22 biochemical variables were determined using Reference Value Advisor software. Lusitano horse-specific RIs are proposed for the following variables: total protein (3.9-7.0 g/dL), albumin (2.5-3.8 g/dL), g...
Andueza D, Martin-Rosset W.The nutritive value of forage for horses is closely dependent on the digestibility of organic matter (OMD), which is typically measured in vivo. Researchers have developed a variety of prediction methods to estimate the digestibility value of hay. In ruminants, pepsin-cellulase degradability, expressed as dry matter enzymatic degradability (dCS) and organic matter enzymatic degradability (dCO), is a commonly employed method for predicting OMD in forage types. The objective of this study was to evaluate the feasibility of predicting the dry matter digestibility (DMD), OMD, energy digestibility ...
Medica AJ, Swegen A, Seifi-Jamadi A, McIntosh K, Gibb Z.Oxidative stress plays a critical role in regulating sperm function, yet species-specific antioxidant mechanisms remain poorly understood. This study compared hydrogen peroxide (H2O2) tolerance in horse and human sperm and investigated the roles of catalase and glutathione peroxidase (GPx) in horses. A H2O2 dose-response assay (0-2000 µM) showed that horse sperm were significantly more resistant to oxidative damage, with an IC50 for progressive motility over 14-fold higher than that of human sperm (391.6 µM vs. 27.3 µM). Horse sperm also accumulated more intracellular H2O2 without loss of m...
Dosi M, Scott L, Payne H, Poldy J, Keen J, McGorum B, Malbon A, Morgan R.Hyperinsulinaemia (HI) is an important feature of Equine Metabolic Syndrome (EMS). It has been suggested that reduced hepatic clearance of insulin contributes to HI, particularly in humans affected by metabolic dysfunction-associated steatotic liver disease (MASLD). Objective: In obese horses with HI, insulin clearance is impaired and associated with MASLD. Methods: Tissue samples were collected at post-mortem from clinically well-characterized horses with HI (n = 13; basal insulin > 20 mIU/l) and without HI (control; n = 20). Methods: Retrospective observational study. Molecular d...
Becerro-Rey L, Martín-Cano FE, Silva-Rodríguez A, Ortega-Ferrusola C, da Silva-Álvarez E, Ortiz-Placín C, Tapia JA, Gil MC, Peña FJ.Three isoforms of lactate dehydrogenase (LDH) - LDHA (cytoplasmic), LDHB (mitochondrial), and LDHC (flagellar) - have been identified and localized in stallion spermatozoa. Functional inhibition assays indicate that these three isoforms constitute a lactate shuttle of crucial importance for sperm function. Unassigned: Stallion spermatozoa use different energy sources; while oxidative phosphorylation predominates, glycolysis and beta-oxidation of fatty acids are also present. Glycolysis depends on the availability of NAD+ as an electron acceptor. During glycolysis, NAD+ is reduced to NADH. To e...
Euppayo T, Siengdee P, Limlenglert P, Nganvongpanit K, Watanabe G, Kasashima Y, Arai K.The self-renewal capacity of chondrocytes in osteoarthritis (OA) joints is limited, and mesenchymal stem cells (MSCs) are crucial in disease treatment. This study established an OA model from equine bone marrow-derived mesenchymal stem cells (eBMSCs). The eBMSCs were cultured and differentiated into chondrocytes to generate cartilage pellets, which were induced for 7 d with inflammatory cytokines, interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) to mimic OA conditions. Treated culture medium was collected to estimate enzyme activity (MMP-2, MMP-3, and MMP-9) using zymograph...
Pipereau K, Trably E, Santa-Catalina G, García-Bernet D, Carrere H.Horse manure is a lignocellulosic biomass found in significant quantities with a vast indigenous flora, not yet fully valorized apart from anaerobic digestion. Its use in the fermentation process can lead to the production of higher-value metabolites. This study investigates three inoculation strategies coupled with five pretreatment conditions for horse manure fermentation. Two microwave pretreatments (200W and 1000W) were compared with a conventional thermal pretreatment, a thermo-acid pretreatment, and an unpretreated condition. The sole horse manure indigenous microorganisms were used in f...
The potential of effective microorganisms in composting animal manure might be significant. This work aimed at isolating promising microbial strains for composting cattle and horse manure. A total of forty-five isolates have been isolated from soils of Northern Kazakhstan as well as cattle and horse manure. These microorganisms were extensively studied for their cellulose-degrading capacity, non-pathogenicity, protease, nitrogenase and catalase activities, as well as their growth stimulation, antagonistic ability, and growth rate. As a result, 21 potent strains were selected and genotyped for ...
Filho RRR, França DS, Alonso MA, Riccio AV, Affonso FJ, Brito MM, Francischini MCP, Nichi M, Boakari Y, Fernandes CB.During gestation, there is a higher energy demand which increases oxygen requirements. As a result, there is an elevated production of reactive oxygen species. Notably, unlike in horses, the effects of maternal age and parity on women's oxidative profiles are well-documented. Thus, this study aimed to investigate oxidative changes in mares during the last third of gestation and the postpartum period, considering age and parity. Seventeen mares were categorized by age (3-7, 8-11, ≥12 years) and parity (nulliparous, 1-3, 4-6 parities). Oxidative processes were assessed using Thiobarbituric Aci...
Kaur K, Sharma D, Haldar KK, Kumar R.Au/ZnO nanocomposites (NCs) were synthesized and characterized by using various analytical techniques. Analysis of Au/ZnO NCs effect on H NMR, CD, fluorescence, and absorbance spectra of horse myoglobin (-Mb) at 0.0 and 5.0 M urea (pH 7.4) revealed that the Au/ZnO NCs weaken the heme-globin interactions and also disrupt the secondary/tertiary structure of -Mb. Furthermore, the Au/ZnO NCs effect of weakening the heme-globin interactions and disrupting the protein structures was detected more in the denaturant media than in the aqueous solution. Analysis of the Au/ZnO NCs effect on thermodynamic...
Connysson M, Jansson A.It is generally accepted that plasma muscle enzyme activity of creatine kinase (CK) and aspartate aminotransferase (AST) may increase in racehorses after exercise and racing, indicating muscle fibre damage and/or increased leakage from muscle fibres. However, other studies suggest that starch intake might influence plasma muscle enzyme activity reported postexercise. This study aimed to evaluate the effect of different starch allowances on plasma muscle enzyme activity in Standardbred trotters in professional training. Seventy-six horses from five professional trainers were sampled pre- and po...
Pipereau K, Trably E, Santa-Catalina G, García-Bernet D, Carrere H.This study focuses on thermal and non-thermal effects of microwave pretreatment on horse dung as indigenous inoculum before xylose and wheat straw fermentation, emphasizing metabolite production and microbial community changes. Two horse dung microwave pretreatments (MW40°C and MW95°C) were compared with a conventional thermal pretreatment (Th95°C) and an unpretreated condition (Ctrl). Microwave heating pretreatment (MW95°C) leads to similar production as a conventional thermal pretreatment (Th95°C) for xylose and wheat straw fermentation while MW40°C treatment was similar to the control...
Holbrook T, Hernandez J, McCarrel T, Lester G, Sleeper M, Domenig O, Adin D.The impact of exercise on the classical and alternative renin-angiotensin-aldosterone system (RAAS) pathways has not been studied in horses. Objective: We hypothesized that exercise would activate both RAAS pathways and that endurance exercise would cause more activation of the classical pathway compared to short-duration, high-intensity exercise in horses. Methods: Twenty-five horses (21 client-owned and 4 research) were included in 4 exercise groups (10 Arabians, 50-mile ride [A-E]; 4 thoroughbreds, 1-mile treadmill exercise [TB-TM]; 5 thoroughbreds, 1-1/16th-mile race [TB-R]; and 6 quarter ...
Hemeda AA, Zahran SA, Ali-Tammam M, Ewida MA, Kashef MT, Yassin AS, Mitra A, Youssef NH, Elshahed MS.The equine gut harbors a diverse microbial community and represents a rich source of carbohydrate-active enzymes (CAZymes). To identify and characterize potentially novel CAZymes from a horse's hindgut metagenome, shotgun metagenomic sequencing was performed on DNA extracted from a stool sample of a male horse, followed by CAZyme annotation. Here, we report on the characterization of a novel enzyme (AH2) that was identified, synthesized, cloned, and characterized from the obtained CAZyme dataset. AH2 was identified as a GH130 family member and displayed exclusive xylanase activity, a trait hit...
The protein journalFebruary 22, 2025
Volume 44, Issue 3 271-282 doi: 10.1007/s10930-025-10259-8
Akay MB, Sener K, Sari S, Bodur E.Butyrylcholinesterase (BChE; EC 3.1.1.8), a serine hydrolase found in various tissues, hydrolyses choline esters such as acetylcholine and succinylcholine, as well as other esters such as heroin and acetylsalicylic acid. It is considered to play a role in lipid metabolism as it belongs to the same enzyme group as lipases and its catalytic subunits are similar. In this study, the effects of unsaturated fatty acids, namely arachidonic (AA), linoleic (LA), alpha-linolenic (ALA) and oleic acid (OA), on equine serum BChE (EqBChE) were investigated. Enzyme activity was measured by the modified Ellma...
Alim S, Cheppali SK, Pawar SS, Swamy MJ.Fibronectin type-II (FnII) proteins are major constituents in the seminal plasma of many mammals and play a crucial role in sperm capacitation. Additionally, the seminal FnII proteins from bull and horse exhibit chaperone-like activity (CLA), by acting as small heat shock proteins (shsps). The present work demonstrates that the major FnII protein of donkey seminal plasma, DSP-1 exhibits CLA with broad specificity and protects various client proteins such as alcohol dehydrogenase, lactate dehydrogenase and enolase against thermal and oxidative stress. Binding of phosphorylcholine (PrC) - the he...
Byambaragchaa M, Park SH, Park MH, Kang MH, Min KS.Equine chorionic gonadotropin (eCG) hormone, comprising highly glycosylated α- and β-subunits, elicits responses similar to follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in non-equid species. This study aimed to establish a mass production of recombinant eCG (rec-eCG) using CHO DG44 cells. Single-chain rec-eCG β/α was expressed in CHO DG44 cells. FSH- and LH-like activities were evaluated in CHO-K1 and HEK 293 cells expressing the equine LH/CG receptor (eLH/CGR), rat LH/CGR (rLH/CGR), and rFSHR. pERK1/2 activation and β-arrestin 2 recruitment were assessed in PathHunter ...
Ma Z, Li Y, Zhao Z, Song Q, Wang Q, Lu S, Wang J.In this study, we purified and identified antioxidant peptides from equine plasma protein hydrolysates and assessed their protective effects against HO-induced oxidative stress in Caco-2 cells. Four antioxidant peptides were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in equine plasma protein hydrolysate, namely: GTMVGC (567.69 Da), FGMTST (662.88 Da), VGYHSHF (847.01 Da) and ALSPFFKE (939.18 Da). Among them, ALSPFFKE showed the strongest antidigestive properties after modelled digestion studies. Moreover, ALSPFFKE enhanced intracellular superoxide dismutase (SO...
Aleman M.Muscle disease has various clinical manifestations that range from exertional and non-exertional rhabdomyolysis, fasciculations, weakness, rigidity, stiffness, gait abnormalities, poor performance, and alterations in muscle mass and tone. Neurogenic disorders and non-neurogenic disorders such as primary muscle disease can cause muscle atrophy and changes in muscle tone. Myotonic disorders can have a genetic (eg, inherited channelopathies) or acquired (eg, electrolyte derangements) origin. Normal muscle enzyme activities do not rule out a myopathic disorder as the underlying cause of muscle atr...
Ishikawa Y, Tufa SF, Keene DR, Bächinger HP, Winand NJ.Mutations in the collagen-modifying enzyme lysyl hydroxylase 1 (LH1) cause Warmblood Fragile Foal Syndrome (WFFS) in horses. We investigated the impact of this mutation on collagen structure and function. Our results show that LH1 deficiency leads to reduced lysine hydroxylation, altered collagen fibril organization, and tissue abnormalities resembling human Ehlers-Danlos syndrome. These findings highlight the critical role of LH1 in collagen biosynthesis and provide insights into the pathogenesis of WFFS.
Aboelmaaty AM, Elgharieb AEA, El-Debaky HA, Alkhadrawy JMH, Abou-Ahmed MM, Ghallab AM.Senility influences fertility in women and companion animals, especially horses. Unassigned: This study aimed to investigate the effect of aging in horses on the daily changes in the dominant follicle (DF) dynamics and hemodynamics, antimüllerian hormone (AMH), enzymes, antioxidants, and ovarian hormones during the estrous cycle. Unassigned: Ovaries of old mares ( = 5, age >20 years) and young native mares ( = 6, age <10 years) were scanned during 6 different estrous cycles from March 2022 to August 2023 with Doppler ultrasound. The DF diameter and color area, the corpus luteum (CL) dia...
Gupta RC, Lall R, Srivastava A, Sinha A.Hyaluronic acid (also known as hyaluronan or hyaluronate) is naturally found in many tissues and fluids, but more abundantly in articular cartilage and synovial fluid (SF). Hyaluronic acid (HA) content varies widely in different joints and species. HA is a non-sulfated, naturally occurring non-protein glycosaminoglycan (GAG), with distinct physico-chemical properties, produced by synoviocytes, fibroblasts, and chondrocytes. HA has an important role in the biomechanics of normal SF, where it is partially responsible for lubrication and viscoelasticity of the SF. The concentration of HA and its ...
Science (New York, N.Y.)December 11, 1992
Volume 258, Issue 5089 1748-1755 doi: 10.1126/science.1334573
Pelletier H, Kraut J.The crystal structure of a 1:1 complex between yeast cytochrome c peroxidase and yeast iso-1-cytochrome c was determined at 2.3 A resolution. This structure reveals a possible electron transfer pathway unlike any previously proposed for this extensively studied redox pair. The shortest straight line between the two hemes closely follows the peroxidase backbone chain of residues Ala194, Ala193, Gly192, and finally Trp191, the indole ring of which is perpendicular to, and in van der Waals contact with, the peroxidase heme. The crystal structure at 2.8 A of a complex between yeast cytochrome c pe...
Costa MC, Silva G, Ramos RV, Staempfli HR, Arroyo LG, Kim P, Weese JS.The advance of new sequencing technologies has allowed more comprehensive characterization of complex microbial communities, including the ones inhabiting the intestinal tract. The presence of extreme environmental filters, such as low pH, digestive enzymes and anaerobic conditions along the tract, acts on the selection of unique bacteria in each compartment. The intestinal microbiota has an enormous impact on the maintenance of health. However, data about the bacteria present in the different intestinal compartments of horses are sparse. In this study, high throughput sequencing was used to c...
van Kasteren PB, Bailey-Elkin BA, James TW, Ninaber DK, Beugeling C, Khajehpour M, Snijder EJ, Mark BL, Kikkert M.Protein ubiquitination regulates important innate immune responses. The discovery of viruses encoding deubiquitinating enzymes (DUBs) suggests they remove ubiquitin to evade ubiquitin-dependent antiviral responses; however, this has never been conclusively demonstrated in virus-infected cells. Arteriviruses are economically important positive-stranded RNA viruses that encode an ovarian tumor (OTU) domain DUB known as papain-like protease 2 (PLP2). This enzyme is essential for arterivirus replication by cleaving a site within the viral replicase polyproteins and also removes ubiquitin from cell...
Schmoldt A, Benthe HF, Haberland G, Jallon JM, Risler Y, Iwatsubo M, Karuzina II, Bachmanova GI, Kuznetsova GP, Izotov MV, Archakov AI, Kröger H....It has been found that NADPH-dependent hydroxylation of dimethylaniline, aniline, p- and o-nitroanisol and lipid peroxidation is inhibited by the tyrosine-copper (II) complex (low molecular weight analog of superoxide dismutase), which is indicative of a possibility of superoxide radicals formation in these reactions. The inhibition of the above-mentioned reactions with Tyr2-Cu2+ is less pronounced or absent, if cumole hydroperoxide is used as cosubstrate instead of NADPH. Differences in the Tyr2-Cu2+ complex effects on the cumule hydroperoxide-dependent xenobiotics hydroxylation and lipid per...
Snijder EJ, Wassenaar AL, Spaan WJ.To study the proteolytic processing of the equine arteritis virus (EAV) replicase open reading frame 1a (ORF1a) protein, specific antisera were raised in rabbits, with six synthetic peptides and a bacterial fusion protein as antigens. The processing of the EAV ORF1a product in infected cells was analyzed with Western blot (immunoblot) and immunoprecipitation techniques. Additional information was obtained from transient expression of ORF1a cDNA constructs. The 187-kDa ORF1a protein was found to be subject to at least five proteolytic cleavages. The processing scheme, which covers the entire OR...
Angele P, Abke J, Kujat R, Faltermeier H, Schumann D, Nerlich M, Kinner B, Englert C, Ruszczak Z, Mehrl R, Mueller R.Collagen-based scaffolds are appealing products for the repair of cartilage defects using tissue engineering strategies. The present study investigated the species-related differences of collagen scaffolds with and without 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS)-crosslinking. Resistance against collagenase digestion, swelling ratio, amino acid sequence, shrinkage temperature, ultrastructural matrix morphology, crosslinking density and stress-strain characteristics were determined to evaluate the physico-chemical properties of equine- and bovine-collagen...
Russo AT, White MA, Watowich SJ.Alphavirus replication and propagation is dependent on the protease activity of the viral nsP2 protein, which cleaves the nsP1234 polyprotein replication complex into functional components. Thus, nsP2 is an attractive target for drug discovery efforts to combat highly pathogenic alphaviruses. Unfortunately, antiviral development has been hampered by a lack of structural information for the nsP2 protease. Here, we report the crystal structure of the nsP2 protease (nsP2pro) from Venezuelan equine encephalitis alphavirus determined at 2.45 A resolution. The protease structure consists of two dist...
Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Marshall WL, Stoian M, Andrews WR.It has been shown that for the reaction catalyzed by "biodegradative" L-threonine dehydratase from E. coli strains K-12 and 980 in 0.5 M phosphate-carbonate buffer, pH 8.4 and pH 9.5, the plots of initial reaction rate (v) versus the initial substrate concentration ([S]0 are characterized by several inflection points, i. e. an intermediate plateau. The plot of v versus the allosteric activator (AMP) concentration have very complicated shapes: there are several inflection points, and also the maximum at L-threonine concentration equal to 3-10(2) and 5-10(-2) M. High AMP concentrations inhibit t...
Lees P, Landoni MF, Giraudel J, Toutain PL.This review summarises selected aspects of the pharmacokinetics (PK) and pharmacodynamics (PD) of nonsteroidal anti-inflammatory drugs (NSAIDs). It is not intended to be comprehensive, in that it covers neither minor species nor several important aspects of NSAID PD. The limited objective of the review is to summarise those aspects of NSAID PK and PD, which are important to an understanding of PK-PD integration and PK-PD modelling (the subject of the next review in this issue). The general features of NSAID PK are: usually good bioavailability from oral, intramuscular and subcutaneous administ...
van Aken D, Zevenhoven-Dobbe J, Gorbalenya AE, Snijder EJ.The positive-stranded RNA genome of the arterivirus Equine arteritis virus (order Nidovirales) encodes the partially overlapping replicase polyproteins pp1a (1727 aa) and pp1ab (3175 aa). Previously, three viral proteinases were reported to cleave these large polyproteins into 12 non-structural proteins (nsps). The chymotrypsin-like viral main proteinase residing in nsp4 is responsible for eight of these cleavages. Processing of the C-terminal half of pp1a (the nsp3-8 region) was postulated to occur following either of two alternative proteolytic pathways (the 'major' and 'minor' pathways). He...
Prokhorov NS, Riccio C, Zdorovenko EL, Shneider MM, Browning C, Knirel YA, Leiman PG, Letarov AV.Bacteriophages recognize and bind to their hosts with the help of receptor-binding proteins (RBPs) that emanate from the phage particle in the form of fibers or tailspikes. RBPs show a great variability in their shapes, sizes, and location on the particle. Some RBPs are known to depolymerize surface polysaccharides of the host while others show no enzymatic activity. Here we report that both RBPs of podovirus G7C - tailspikes gp63.1 and gp66 - are essential for infection of its natural host bacterium E. coli 4s that populates the equine intestinal tract. We characterize the structure and funct...
Cross AR, Higson FK, Jones OT, Harper AM, Segal AW.1. The absorption coefficient of human neutrophil plasma-membrane reduced-minus-oxidized cytochrome b-245 was determined [delta epsilon (mM; 559-540 nm) = 21.6 cm-1]. 2. Neutrophil polymorphonuclear leucocytes (neutrophils) were prepared from human, ox, horse and pig blood. In each case plasma-membrane fractions were found to contain low-potential cytochrome b. When membranes from horse neutrophils were incubated anaerobically with either NADH or NADPH the cytochrome b became reduced. Prior stimulation of the cells with phorbol myristate acetate did not increase the rate or extent of cytochrom...
Schenkman KA, Marble DR, Burns DH, Feigl EO.Multiwavelength optical spectroscopy was used to determine the oxygen-binding characteristics for equine myoglobin. Oxygen-binding relationships as a function of oxygen tension were determined for temperatures of 10, 25, 35, 37, and 40 degrees C, at pH 7.0. In addition, dissociation curves were determined at 37 degrees C for pH 6.5, 7.0, and 7.5. Equilibration was achieved with a myoglobin solution, at the desired temperature and pH, and 16 oxygen-nitrogen gas mixtures of known oxygen fraction. Correction for the inevitable presence of metmyoglobin was made by using a three-component least squ...
Magneson GR, Puvathingal JM, Ray WJ.The enzyme phosphoglucomutase can be used as a metal ion indicator to measure the concentrations of free Mg2+ and free Zn2+ in physiological fluids. In horse plasma, the concentration of free Mg2+ is close to 0.5 mM, whereas that of free Zn2+ is about 2 X 10(-10) M, although numerous physiological roles for Zn2+ have been postulated that would require free Zn2+ concentration orders of magnitude higher than this. A titration of plasma with Zn2+ shows that the fractional increase in free Zn2+ is essentially the same as the fractional increase in total exchangeable Zn2+, and the results are consi...
Visser J, Levett PA, te Moller NC, Besems J, Boere KW, van Rijen MH, de Grauw JC, Dhert WJ, van Weeren PR, Malda J.Decellularized tissues have proven to be versatile matrices for the engineering of tissues and organs. These matrices usually consist of collagens, matrix-specific proteins, and a set of largely undefined growth factors and signaling molecules. Although several decellularized tissues have found their way to clinical applications, their use in the engineering of cartilage tissue has only been explored to a limited extent. We set out to generate hydrogels from several tissue-derived matrices, as hydrogels are the current preferred cell carriers for cartilage repair. Equine cartilage, meniscus, a...
Westhoff D, Kamp G.Evidence is provided that the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase is covalently linked to the fibrous sheath. The fibrous sheath is a typical structure of mammalian spermatozoa surrounding the axoneme in the principal piece of the flagellum. More than 90% of boar sperm glyceraldehyde 3-phosphate dehydrogenase activity is sedimented after cell disintegration by centrifugation. Detergents, different salt concentrations or short term incubation with chymotrypsin do not solubilize the enzyme, whereas digestion with trypsin or elastase does. Short term incubation with trypsin...
Lichtenstein DL, Rushlow KE, Cook RF, Raabe ML, Swardson CJ, Kociba GJ, Issel CJ, Montelaro RC.As an important enzyme in DNA synthesis, dUTPase is present in a wide variety of organisms and viruses and has been identified as a component of the equine infectious anemia virus (EIAV) pol gene. The role of EIAV dUTPase, designated DU, in virus replication in vitro and in vivo was investigated with a recently described infectious molecular clone of EIAV. A deletion mutant that was deficient in dUTPase activity was constructed, and its replication kinetics was examined in fetal equine kidney (FEK) cells and primary equine bone marrow macrophage (EBMM) cells. In FEK cells, which are permissive...
Kamm JL, Nixon AJ, Witte TH.Understanding the expression of catabolic and anabolic genes during osteoarthritis progression should help to identify the major mediators of the disease. Objective: To compare the cytokine and anabolic marker concentrations in synovium, synovial fluid and cartilage between normal and osteoarthritic joints. Methods: Carpi from horses age 2-11 years were used. Tissues were harvested at the time of surgery or euthanasia, and RNA was isolated for RT-PCR analysis. Tumour necrosis factor alpha (TNFα), interleukin-1beta (IL-1β), aggrecanase 1 (ADAMTS-4), aggrecanase 2 (ADAMTS-5), matrix metallopro...
Barrachina L, Remacha AR, Romero A, Vitoria A, Albareda J, Prades M, Roca M, Zaragoza P, Vázquez FJ, Rodellar C.This study aimed at assessing the effectiveness and safety of repeated administrations of allogeneic bone marrow-derived mesenchymal stem cells (BM-MSCs) primed with tumor necrosis factor (TNF)-α and interferon-γ in an equine model of chemically-induced osteoarthritis. Arthritis was induced in both radio-carpal (RC)-joints by amphotericin-B in 18 ponies, divided into three groups depending on the treatment injected: MSC-naïve (n = 7), MSC-primed (n = 7) and control (n = 4). The study consisted of two phases and used one RC-joint of each animal in each phase, with four months tim...
Liu JX, Höglund AS, Karlsson P, Lindblad J, Qaisar R, Aare S, Bengtsson E, Larsson L.This comparative study of myonuclear domain (MND) size in mammalian species representing a 100,000-fold difference in body mass, ranging from 25 g to 2500 kg, was undertaken to improve our understanding of myonuclear organization in skeletal muscle fibres. Myonuclear domain size was calculated from three-dimensional reconstructions in a total of 235 single muscle fibre segments at a fixed sarcomere length. Irrespective of species, the largest MND size was observed in muscle fibres expressing fast myosin heavy chain (MyHC) isoforms, but in the two smallest mammalian species studied (mouse and r...
Threadgill DS, Steagall WK, Flaherty MT, Fuller FJ, Perry ST, Rushlow KE, Le Grice SF, Payne SL.The putative dUTPase domain was deleted from the polymerase (pol) gene of equine infectious anemia virus (EIAV) to produce a recombinant delta DUpol Escherichia coli expression cassette and a delta DU proviral clone. Expression of the recombinant delta DUpol polyprotein yielded a properly processed and enzymatically active reverse transcriptase, as determined by immunoblot analysis and DNA polymerase activity gels. Transfection of delta DU provirus into feline (FEA) cells resulted in production of virus that replicated to wild-type levels in both FEA cells and fetal equine kidney cells. In con...
Higgins AJ, Lees P.Arachidonic acid is a polyunsaturated fatty acid covalently bound in esterified form in the cell membranes of most body cells. Following irritation or injury, arachidonic acid is released and oxygenated by enzyme systems leading to the formation of an important group of inflammatory mediators, the eicosanoids. It is now recognised that eicosanoid release is fundamental to the inflammatory process. For example, the prostaglandins and other prostanoids, products of the cyclooxygenase enzyme pathway, have potent inflammatory properties and prostaglandin E2 is readily detectable in equine acute in...
Doré M.Cyclooxygenase (COX; also known as prostaglandin endoperoxide synthase) is a key enzyme in the biochemical pathway leading to the synthesis of prostaglandins. A large amount of epidemiological and experimental evidence supports a role for COX-2, the inducible form of the enzyme, in human tumorigenesis, notably in colorectal cancer. COX-2 mediates this role through the production of PGE(2) that acts to inhibit apoptosis, promote cell proliferation, stimulate angiogenesis, and decrease immunity. Similarly, COX-2 is believed to be involved in the oncogenesis of some cancers in domestic animals. H...
Beretta C, Garavaglia G, Cavalli M.We report on the inhibitory activity of the NSAIDs meloxicam, carprofen, phenylbutazone and flunixin, on blood cyclooxygenases in the horse using in vitro enzyme-linked assays. As expected, comparison of IC50 indicated that meloxicam and carprofen are more selective inhibitors of COX-2 than phenylbutazone and flunixin; meloxicam was the most advantageous for horses of four NSAIDs examined. However at IC80, phenylbutazone (+134.4%) and flunixin (+29.7%) had greater COX-2 selectivity than at IC50, and meloxicam (-41.2%) and carprofen (-12.9%) had lower COX-2 selectivity than at IC50. We therefor...
Lindholm A, Piehl K.LINDHOLM, ARNE and KARIN PIEHL: Acta vet. scand. 1974, , 287–309. — Measurements of metabolites, electrolytes, water, RNA and protein concentrations, the activity of certain muscle enzymes (SDH and PFK) and muscle fibre composition were made on biopsy specimens from the gluteus medius muscle of 68 standardbred horses, ½ to 8 years old. The muscle fibres were classified in 3 major categories, slow twitch (ST), fast twitch and high oxidative (FTH) and fast twitch (FT) fibres. The percentage of FTH fibres was higher after the age of 4 years, averaging 54 %. ST fibres comprised 24 % and this...
