RESUMO
Researchers have reported the benefits of feeding rumen-protected methionine (RPM) during the peripartum on the health parameters of dairy cows. Rumen-protected Met has reportedly improved milk yield, milk components, and liver health, but the literature is scarce on its effects in commercial herds. Therefore, we aimed to determine the effects of feeding RPM (Smartamine M, Adisseo Inc., Antony, France) prepartum (8 g/cow per day) and postpartum (15 g/cow per day) on performance, metabolic profile, and culling rate of Holstein cows in a commercial herd. One hundred sixty-six (n = 166) Holstein cows, 58 nulliparous and 108 parous, were randomly assigned to 1 of 2 dietary treatments, consisting of TMR top-dressed with RPM (RPMet; 2.35% and 2.24% Met of MP for close-up and fresh cows, respectively) or without (control [CON] 2.03% and 1.89% Met of MP for close-up and fresh cows, respectively), fed from 21 ± 6 d prepartum until 16 ± 5 d postpartum. From 17 DIM until dry-off, all cows received RPMet. Daily milk yield was recorded, and milk samples were collected in the first and second weeks after calving to determine their composition. Blood samples were collected before the morning feeding on -14, -7, +1, +7, and +14 d relative to calving. Mortality and morbidity were recorded during the first 60 DIM. Cows supplemented with RPMet had greater milk yield during the first 16 DIM (31.76 vs. 30.37 kg/d; SEM = 1.04, respectively), and had greater milk fat content (4.45 vs. 4.10%; SEM = 0.11, respectively), but not milk total protein (3.47 vs. 3.39%; SEM = 0.04, respectively) and casein contents (2.74 vs. 2.66%; SEM = 0.04, respectively) than CON cows. Cows in RPMet had increased plasma Met concentrations than cows in CON (24.9 vs. 21.0 µmol/L; SEM = 1.2, respectively). Although morbidity was similar between treatments, the culling rate from calving until 60 DIM was lower for RPMet cows than for CON cows (2.4% vs. 12.1%; SEM = 0.02). In conclusion, cows receiving RPMet have greater milk yield, improved milk fat content, and a lower culling rate at 60 DIM than CON cows.
Assuntos
Ração Animal , Dieta , Lactação , Metionina , Leite , Período Periparto , Rúmen , Animais , Bovinos , Metionina/metabolismo , Metionina/administração & dosagem , Feminino , Leite/química , Leite/metabolismo , Dieta/veterinária , Rúmen/metabolismo , Ração Animal/análiseRESUMO
The oxidation of Met to methionine sulfoxide (MetSO) by oxidants such as hydrogen peroxide, hypochlorite, or peroxynitrite has profound effects on protein function. This modification can be reversed by methionine sulfoxide reductases (msr). In the context of pathogen infection, the reduction of oxidized proteins gains significance due to microbial oxidative damage generated by the immune system. For example, Mycobacterium tuberculosis (Mt) utilizes msrs (MtmsrA and MtmsrB) as part of the repair response to the host-induced oxidative stress. The absence of these enzymes makes Mycobacteria prone to increased susceptibility to cell death, pointing them out as potential therapeutic targets. This study provides a detailed characterization of the catalytic mechanism of MtmsrA using a comprehensive approach, including experimental techniques and theoretical methodologies. Confirming a ping-pong type enzymatic mechanism, we elucidate the catalytic parameters for sulfoxide and thioredoxin substrates (kcat/KM = 2656 ± 525 M-1 s-1 and 1.7 ± 0.8 × 106 M-1 s-1, respectively). Notably, the entropic nature of the activation process thermodynamics, representing â¼85% of the activation free energy at room temperature, is underscored. Furthermore, the current study questions the plausibility of a sulfurane intermediate, which may be a transition-state-like structure, suggesting the involvement of a conserved histidine residue as an acid-base catalyst in the MetSO reduction mechanism. This mechanistic insight not only advances our understanding of Mt antioxidant enzymes but also holds implications for future drug discovery and biotechnological applications.
Assuntos
Metionina Sulfóxido Redutases , Mycobacterium tuberculosis , Metionina Sulfóxido Redutases/metabolismo , Mycobacterium tuberculosis/metabolismo , Oxirredução , Catálise , Estresse Oxidativo , Metionina/metabolismoRESUMO
Rickettsia typhi is the causative agent of murine typhus (endemic typhus), a febrile illness that can be self-contained, though in some cases it can progress to death. The three dimensional structure of Methionyl-tRNA Synthetase from R. typhi (RtMetRS) in complex with its substrate l-methionine was solved by molecular replacement and refined at 2.30 Å resolution in space group P1 from one X-ray diffraction dataset. Processing and refinement trials were decisive to establish the lower symmetry space group and indicated the presence of twinning with four domains. RtMetRS belongs to the MetRS1 family and was crystallized with the CP domain in an open conformation, what is distinctive from other MetRS1 enzymes whose structures were solved with a bound L-methionine (therefore, in a closed conformation). This conformation resembles the ones observed in the MetRS2 family.
Assuntos
Metionina tRNA Ligase , Animais , Camundongos , Metionina tRNA Ligase/química , Metionina tRNA Ligase/genética , Metionina tRNA Ligase/metabolismo , Aminoácidos , Rickettsia typhi/metabolismo , Difração de Raios X , Metionina/metabolismoRESUMO
Tambaqui (Colossoma macropomum) is a species of great cultural and economic importance in aquaculture in the Amazon region. Methionine is considered the first limiting sulfur amino acid in practical fish diets, which encourages investigating its use in diets for tambaqui. This study aimed to verify the digestible methionine plus cystine (Met + Cys) requirement in diets for tambaqui (89.52 ± 0.53 g) for 60 days. The treatments investigated were: 6.50, 7.80, 9.10, 10.40, 11.70, and 13.00 g Met + Cys kg diet-1. The estimated requirement based on final weight, weight gain, feed conversion ratio, and specific growth rate was 9.04, 8.92, 8.91, and 8.58 g Met + Cys kg diet-1, respectively, while on body protein deposition, body fat deposition, body ash deposition, and nitrogen retention efficiency was 9.29, 9.20, 9.19, and 8.72 g Met + Cys kg diet-1, respectively. Linear regression demonstrated that increased digestible Met + Cys in the diet decreased plasma total protein, globulin, and liver total protein levels. Quadratic regression showed that the highest value for liver glycogen was found with a 10.40 g Met + Cys kg diet-1. Another quadratic regression demonstrated a lower hepatic aspartate aminotransferase (AST) enzymatic activity in fish fed between 7.80 and 11.70 g Met + Cys kg diet-1. The different treatments did not influence the erythrogram. In conclusion, when considering an integrative view of the results for growth performance, whole-body deposition, and liver parameters without harming the physiological and metabolic status, we recommended choosing a diet with digestible Met + Cys between 8.58 and 9.29 g kg- 1 for tambaqui.
Assuntos
Aminoácidos Sulfúricos , Metionina , Animais , Metionina/metabolismo , Cistina/metabolismo , Aminoácidos Sulfúricos/metabolismo , Racemetionina/metabolismo , Dieta/veterinária , Composição Corporal , Fígado/metabolismo , Ração Animal/análiseRESUMO
Trypanosoma cruzi is the causal agent of Chagas Disease and is a unicellular parasite that infects a wide variety of mammalian hosts. The parasite exhibits auxotrophy by L-Met; consequently, it must be acquired from the extracellular environment of the host, either mammalian or invertebrate. Methionine (Met) oxidation produces a racemic mixture (R and S forms) of methionine sulfoxide (MetSO). Reduction of L-MetSO (free or protein-bound) to L-Met is catalyzed by methionine sulfoxide reductases (MSRs). Bioinformatics analyses identified the coding sequence for a free-R-MSR (fRMSR) enzyme in the genome of T. cruzi Dm28c. Structurally, this enzyme is a modular protein with a putative N-terminal GAF domain linked to a C-terminal TIP41 motif. We performed detailed biochemical and kinetic characterization of the GAF domain of fRMSR in combination with mutant versions of specific cysteine residues, namely, Cys12, Cys98, Cys108, and Cys132. The isolated recombinant GAF domain and full-length fRMSR exhibited specific catalytic activity for the reduction of free L-Met(R)SO (non-protein bound), using tryparedoxins as reducing partners. We demonstrated that this process involves two Cys residues, Cys98 and Cys132. Cys132 is the essential catalytic residue on which a sulfenic acid intermediate is formed. Cys98 is the resolutive Cys, which forms a disulfide bond with Cys132 as a catalytic step. Overall, our results provide new insights into redox metabolism in T. cruzi, contributing to previous knowledge of L-Met metabolism in this parasite.
Assuntos
Metionina Sulfóxido Redutases , Trypanosoma cruzi , Metionina Sulfóxido Redutases/genética , Metionina Sulfóxido Redutases/química , Metionina Sulfóxido Redutases/metabolismo , Trypanosoma cruzi/genética , Oxirredução , Cisteína/química , Metionina/metabolismoRESUMO
Supplementation of rumen-protected amino acids may improve dairy cow performance but few studies have evaluated the implications of supplementing low-forage diets. Our objective was to evaluate the effects of supplementing rumen-protected methionine (Met) and lysine (Lys) on milk production and composition as well as on mammary gland health of mid-lactating Holstein cows from a commercial dairy farm feeding a high by-product low-forage diet. A total of 314 multiparous cows were randomly assigned to control (CON; 107 g of dry distillers' grains) or rumen-protected Met and Lys (RPML; 107 g dry distillers' grains + 107 g of RPML). All study cows were grouped in a single dry-lot pen and fed the same total mixed ration diet twice a day for a total of 7 weeks. Treatments were top-dressed on the total mix ration immediately after morning delivery with 107 g of dry distillers' grains for 1 week (adaptation period) and then with CON and RPML treatments for 6 weeks. Blood samples were taken from a subset of 22 cows per treatment to determine plasma AA (d 0 and 14) and plasma urea nitrogen and minerals (d 0, 14, and 42). Milk yield and clinical mastitis cases were recorded daily, and milk components were determined bi-weekly. Body condition score change was evaluated from d 0 to 42 of the study. Milk yield and components were analyzed by multiple linear regression. Treatment effects were evaluated at the cow level considering parity and milk yield and composition taken at baseline as a covariate in the models. Clinical mastitis risk was assessed by Poisson regression. Plasma Met increased (26.9 vs 36.0 µmol/L), Lys tended to increase (102.5 vs 121.1 µmol/L), and Ca increased (2.39 vs 2.46 mmol/L) with RPML supplementation. Cows supplemented with RPML had higher milk yield (45.4 vs 46.0 kg/d) and a lower risk of clinical mastitis (risk ratio = 0.39; 95% CI = 0.17-0.90) compared to CON cows. Milk components yield and concentrations, somatic cell count, body condition score change, plasma urea nitrogen, and plasma minerals other than Ca were not affected by RPML supplementation. Results suggest that RPML supplementation increases milk yield and decreases the risk of clinical mastitis in mid-lactation cows fed a high by-product low-forage diet. Further studies are needed to clarify the biological mechanisms for mammary gland responses to RPML supplementation.
Assuntos
Lactação , Lisina , Gravidez , Feminino , Bovinos , Animais , Lisina/metabolismo , Lactação/fisiologia , Metionina/metabolismo , Paridade , Rúmen/metabolismo , Dieta/veterinária , Suplementos Nutricionais , Leite/metabolismo , Racemetionina/metabolismo , Nitrogênio/metabolismo , Minerais/metabolismo , Ureia/metabolismo , Ração Animal/análiseRESUMO
This study investigated the hypothesis that methionine supplementation of Japanese quail (Coturnix coturnix japonica) hens can reduce the effects of oxidative stress and improve the performance of the offspring exposed to heat stress during growth. For that, the quail hens were fed with three diets related to the methionine supplementation: methionine-deficient diet (Md); diet supplemented with the recommended methionine level (Met1); and diet supplemented with methionine above the recommended level (Met2). Their chicks were identified, weighed, and housed according to the maternal diet group from 1 to 14 d of age. On 15 d of age, chicks were weighed and divided into two groups: thermoneutral ambient (constant temperature of 23 °C) and intermittent heat stress ambient (daily exposure to 34 °C for 6 h). Methionine-supplemented (Met1 and Met2) hens had higher egg production, better feed conversion ratio, higher hatchability of total and fertile eggs, and offspring with higher body weight. Supplemented (Met1 and Met2) hens showed greater expression of glutathione synthase (GSS) and methionine sulfoxide reductase A (MSRA) genes, greater total antioxidant capacity, and lower lipid peroxidation in the liver. The offspring of hens fed the Met2 diet had lower death rate (1 to 14 d), higher weight on 15 d of age, weight gain, and better feed conversion ratio from 1 to 14 d of age. Among chicks reared under heat stress, the progeny of methionine-supplemented hens had higher weight on 35 d, weight gain, expression of GSS, MSRA, and thermal shock protein 70 (HSP70) genes, and total antioxidant capacity in the liver, as well as lower heterophil/lymphocyte ratio. Positive correlations between expression of glutathione peroxidase 7 (GPX7) and MSRA genes in hens and offspring were observed. Our results show that maternal methionine supplementation contributes to offspring development and performance in early stages and that, under conditions of heat stress during growth, chicks from methionine-supplemented hens respond better to hot environmental conditions than chicks from nonsupplemented hens. Supplementation of quail hens diets with methionine promoted activation of different metabolic pathways in offspring subjected to stress conditions.
The deficiency of nutrients such as methionine in the diet of birds is affecting fertility rate, egg production, egg weight, and progeny weight. In addition, the maternal environment influences gene expression through epigenetic mechanisms, where the conditions experienced by the parental generation during embryonic development can produce effects on the progeny. This study investigates how methionine supplementation in the diet of quail hens can reduce the effects of oxidative stress and improve the performance of progeny subjected to heat stress during growth. For that, the quail hens were fed with diets containing three different levels of methionine; and their chicks were created (15 on 35 d of age) into thermoneutral and/or intermittent heat stress ambient. It was observed that methionine supplementation in the quail hens had a positive effect on mortality during the initial phase and greater weight gain in the progeny growth phase. In addition, genetic inheritance was observed through the positive correlation between the expression of genes (maternal and progeny) related to oxidative stress. The results show that methionine supplementation in the maternal diet contributes to the development and performance of the progeny when subjected to heat stress during the growth phase.
Assuntos
Antioxidantes , Coturnix , Animais , Feminino , Antioxidantes/metabolismo , Coturnix/fisiologia , Dieta/veterinária , Suplementos Nutricionais , Resposta ao Choque Térmico , Metionina/farmacologia , Metionina/metabolismo , Óvulo , Codorniz , Racemetionina/metabolismo , Aumento de PesoRESUMO
Nonalcoholic steatohepatitis (NASH) is a disease with a high incidence worldwide, but its diagnosis and treatment are poorly managed. In this study, NASH pathophysiology and DNA damage biomarkers were investigated in mice with NASH treated and untreated with melatonin (MLT). C57BL/6 mice were fed a methionine- and choline-deficient (MCD) diet for 4 weeks to develop NASH. Melatonin was administered at 20 mg/kg during the last 2 weeks. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured, and hepatic tissue was dissected for histological analysis, evaluation of lipoperoxidation, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as nuclear factor-erythroid 2 (Nrf2), tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), and transforming growth factor beta (TGF-ß) expression by immunohistochemistry. DNA damage was evaluated using Comet assay, while a micronucleus test in bone marrow was performed to assess the genomic instability associated with the disease. Melatonin decreased AST and ALT, liver inflammatory processes, balloonization, and fibrosis in mice with NASH, decreasing TNF-α, iNOS, and TGF-ß, as well as oxidative stress, shown by reducing lipoperoxidation and intensifying Nrf2 expression. The SOD and GPx activities were increased, while CAT was decreased by treatment with MLT. Although the micronucleus frequency was not increased in mice with NASH, a protective effect on DNA was observed with MLT treatment in blood and liver tissues using Comet assay. As conclusions, MLT slows down the progression of NASH, reducing hepatic oxidative stress and inflammatory processes, inhibiting DNA damage via anti-inflammatory and antioxidant actions.
Assuntos
Deficiência de Colina , Melatonina , Hepatopatia Gordurosa não Alcoólica , Alanina Transaminase , Animais , Anti-Inflamatórios/farmacologia , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Aspartato Aminotransferases , Biomarcadores/metabolismo , Catalase/metabolismo , Colina/análise , Colina/metabolismo , Colina/farmacologia , Deficiência de Colina/complicações , Deficiência de Colina/metabolismo , Dano ao DNA , Dieta , Glutationa Peroxidase/metabolismo , Inflamação/metabolismo , Fígado/metabolismo , Melatonina/farmacologia , Melatonina/uso terapêutico , Metionina/análise , Metionina/genética , Metionina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Estresse Oxidativo , Superóxido Dismutase/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
1. Cobb and Ross broilers (200 of each sex and breed) were fed four phases of diets ad libitum formulated with balanced protein to match their amino acid requirements throughout growth. Ten birds per genotype were sampled and euthanised at two-weekly intervals from 14 to 112 d of age. All feathers were dry-plucked from each of the seven tracts (specific skin areas) and pulp (the centre of the feather filament) was removed from primary and secondary remiges.2. Daily losses of feathers were collected from an additional 20 individually-caged broilers of each breed. These feathers were separated into natal down, contour feathers, remiges and rectrices and then pooled by type, sex and genotype to quantify water and protein contents. Only those feathers collected from male Cobb 500 MX broilers were analysed for amino acid content.3. Amino acid contents of feathers from the seven tracts were measured only in Cobb males on days 1, 28 and 70; for pulp on days 28 and 70; and for the four types of moulted feathers.4. Protein content on a dry matter basis remained relatively constant over all ages and tracts during growth. Water content decreased with age in both sexes and genotype. Lysine and methionine content in feathers decreased with age while cystine, valine, leucine and serine increased. Lysine, methionine and histidine levels were higher in pulp than in mature feathers whereas cystine and valine were higher in mature feathers than in pulp.5. These results, together with information about moulting patterns in broilers, enabled the effects of age of the bird and of the type of feather, to be taken into account when determining the rate of deposition of amino acids in feathers.
Assuntos
Galinhas , Plumas , Aminoácidos/metabolismo , Animais , Cistina/metabolismo , Plumas/química , Feminino , Genótipo , Lisina/análise , Masculino , Metionina/metabolismo , Proteínas/análise , Valina/análise , Valina/metabolismo , Água/análiseRESUMO
Amyloid aggregation of α-synuclein (AS) is one of the hallmarks of Parkinson's disease (PD). Copper ions specifically bind at the N-terminus of AS, accelerating protein aggregation. Its protein homolog ß-synuclein (BS) is also a copper binding protein, but it inhibits AS aggregation. Here, a comparative spectroscopic study of the Cu2+ binding properties of AS and BS has been performed, using electronic absorption, circular dichroism (CD) and electronic paramagnetic resonance (EPR). Our comparative spectroscopic study reveals striking similarities between the Cu2+ binding features of the two proteins. The Cu2+ binding site at the N-terminal group of BS protein, modeled by the BS (1-15) fragment is identical to that of AS; however, its rate of reduction is three times faster as compared to the AS site, consistent with BS having an additional Met residue in its Met1-Xn-Met5-Xn-Met10 motif. The latter is also evident in the cyclic voltammetry studies of the Cu-BS complex. On the other hand, the Cu2+ binding features of the His site in both proteins, as modeled by AS(45-55) and BS(60-70), are identical, indicating that the shift in the His position does not affect its coordination features. Finally, replacement of Glu46 by Ala does not alter Cu2+ binding to the His site, suggesting that the familial PD E46K mutation would not impact copper-induced aggregation. While further studies of the redox activity of copper bound to His50 in AS are required to understand the role of this site in metal-mediated aggregation, our study contributes to a better understanding of the bioinorganic chemistry of PD.