Addition of dietary methionine but not dietary taurine or methyl donors/receivers to a grain-free diet increases postprandial homocysteine concentrations in adult dogs

Grain based ingredients are replaced in part by pulse ingredients in grain-free pet foods. Pulse ingredients are lower in methionine and cysteine, amino acid (AA) precursors to taurine synthesis in dogs. While recent work has investigated plasma and whole blood taurine concentrations when feeding grain-free diets, supplementation of a grain-free diet with various nutrients involved in the biosynthesis of taurine has not been evaluated. This study aimed to investigate the effects of supplementing a complete grain-free dry dog food with either methionine (MET), taurine (TAU), or methyl donors (choline) and methyl receivers (creatine and carnitine; CCC) on postprandial AA concentrations. Eight healthy Beagle dogs were fed 1 of 3 treatments or the control grain-free diet (CON) for 7 d in a 4 × 4 Latin square design. On d7, cephalic catheters were placed and one fasted sample (0 min) and a series of 9 post-meal blood samples were collected at 15, 30, 60, 90, 120, 180, 240, 300 and 360 min. Data were analyzed as repeated measures using the PROC GLIMMIX function in SAS (Version 9.4). Dogs fed MET had greater plasma and whole blood methionine concentrations from 30 - 360 min after a meal (P < 0.0001) and greater plasma homocysteine concentrations from 60 - 360 min after a meal (P < 0.0001) compared to dogs fed CON, TAU and CCC. Dogs fed TAU had greater plasma taurine concentrations over time compared to dogs fed CON (P = 0.02), but were not different than dogs fed MET and CCC (P > 0.05). In addition, most AA remained significantly elevated at 6 h post-meal compared to fasted samples across all treatments. Supplementation of creatine, carnitine and choline in grain-free diets may play a role in sparing the methionine requirement without increasing homocysteine concentrations. Supplementing these nutrients could also aid in the treatment of disease that causes metabolic or oxidative stress, including cardiac disease in dogs, but future research is required.

Renocardiac Syndrome Induced by Renal Ischemia and Reperfusion: Vibrational Markers

Renal injury caused by renal ischemia and reperfusion is capable to change heart morphology, electrophysiology, and redox unbalance. The so-called cardio-renal syndrome is an important class of dysfunction since heart and kidneys are responsible for hemodynamic stability and organ perfusion through a complex network. In the present work we investigate the Fourier-Transform Raman vibrational spectral features of cardiac hypertrophy induced by renal ischemic reperfusion. C57BL/6J mice were subjected to unilateral occlusion of the renal pedicle for 60 minutes and reperfused for 5 days, 8 days, and 15 days. It was observed that bands around 540, 1100, 1300, 1450, 1650, and 2500 cm-1 dominates the spectra. They are associated to stretching of S-S in Cysteine amino acid, stretching of C-C in lipids, twisting of CH2 in collagen and phospholipids, bending modes of CH3 in lipids and amino acids side chains, Amide I vibration of proteins. The intensities of these vibrations are modulated during renocardiac syndrome. We find that tyrosine, tryptophan, cystine/cysteine, fibroblast growth factors, collagen III alterations from homeostasis were the metabolites associate with these changes. These findings are clinically relevant once the presented bands can be used as molecular markers of preventing cardiac diseases’ development in patients with renal injury.

Intrinsic folding of the cysteine residue: competition between folded and extended forms mediated by the –SH group

A dual microwave and optical spectroscopic study of a capped cysteine amino acid isolated in a supersonic expansion, combined with quantum chemistry modelling, enabled us to access the conformational preferences of Cys embedded in a protein chain.

Effects of Methionine-Cysteine Amino Acid Supplementations in the Aflatoxin B1 Contaminated Diet on Broiler Production Performance

This research aimed to observe the interaction of methionine-cysteine amino acid supplementation to decrease the effect of aflatoxin B1 (AFB1) on diet against production performance of broiler chicken. A number of 240 mixed sex broiler chickens were treated in 9 treatments by factorial design 3 x 3 with methionine-cysteine amino acid (M+C) (75,100, dan 125%) factors and AFB1 levels (0, 200, dan 400 ppb). Variables observed were: Weight gain, feed consumption, and feed conversion ratio (FCR). The results showed that increased AFB1 content in diet from 0 to 400 ppb increased chicken body weight (P <0.05) in each age group. The high body weight was balanced with high feed consumption along with increased nutrient needs, mainly sulfuric amino acid (M+C) as the precursor of glutathione to eliminate toxic through conjugation reactions. The interaction effect was firstly occurred between M + C and AFB1 treatment (P <0.05). Meanwhile increased supplementation of M + C from 75 to 125% caused decreased feed consumption in each age group of chickens, but increased AFB1 levels further increased feed consumption (P<0.05). The interaction effect between the level of M + C and AFB1 contamination in diets on feed consumption were seen in 21-day-old chickens (P<0.05). FCR was also increased (P <0.05) with the reduction of M + C content in diet at 7 days old. The effect of AFB1 on diet and interaction between M + C and AFB1 on chicken FCR in this study was not significant in all age groups. It can be concluded from the current study that supplying methionine-cystine amino acid with 75, 100 and 125% in AFB1 contaminated diet of 0, 200 and 400 ppb improves the performance of broiler chicken production.

The Mystery of "Magic Blood" - Familial Macrothrombocytopenia Associated with a Novel Variant in GP1BA Gene

Introduction: Inherited macrothrombocytopenias comprise a heterogeneous group of rare inherited disorders characterized by decreased platelet count with enlarged platelet size. Glycoprotein Ib (GP Ib) is a platelet surface membrane glycoprotein that is encoded by GP1BA gene, and functions as a receptor for von Willebrand factor (VWF). Mutations in the GP1BA gene are seen in Bernard-Soulier syndrome (BSS). Here we describe a family with an isolated giant platelet disorder and a novel variant in the GP1BA gene following an autosomal dominant mode of inheritance. In our kindred this variant was not associated with clinical history or specific laboratory evidence of BSS. Case Presentation: 34-year-old female reported first being diagnosed with macrothrombocytopenia at the age of 13 on routine blood work. The patient and 11 of her relatives spanning 5 generations have reported asymptomatic macrothrombocytopenia (Figure 1), described as "Magic Blood" by her family. Her platelet count fell below 20,000/microL during one of her pregnancies. She was treated as idiopathic thrombocytopenic purpura (ITP) and was given corticosteroids to increase platelet count without improvement. On presentation, patient's complete blood count was significant for low platelet at 55,000/microL and macrothrombocytes were observed on blood smear. Methods/Results: VWF assays, including Factor VIII activity, VWF Ag, and Ristocetin Cofactor, were within normal limits. VWF multimer analysis revealed a normal pattern and distribution of bands. Patient had a normal platelet aggregation in response to ADP, Collagen, Epinephrine, Ristocetin and Arachidonate. Flow Cytometry detected normal GP Ib and GP IIb/ IIIa expression. Whole exome sequencing and copy number analysis of 29 genes associated with thrombocytopenia revealed a c.97T>G substitution in the GP1BA gene predicted to result in the amino acid substitution p.Cys33Gly (Figure 2). To our knowledge, this variant has not been reported in the literature or public databases. To confirm this novel variant is the cause of the familiar macrothrombocytopenia, two relatives with macrothrombocytopenia, a maternal uncle and a first cousin, also underwent genetic testing and were found to have the same variant. Discussion: Variants in GP1BA are associated with both autosomal dominant and recessive forms of BSS and with autosomal dominant platelet-type VWD. Our kindred is surprisingly asymptomatic given the location and specific amino acid substitution generated by the variant. Amino acid residue p.Cys33 resides in an extracellular N-terminal domain that is critical for VWF binding and proper assembly of the GP1B-IX complex. A heterozygous substitution involving the same amino acid residue defined as p.Cys33Arg was observed in two patients with macrothrombocytopenia with no reported bleeding complications (MC, unpublished data). Substitution of a nearby cysteine residue defined as p.Cys20Gly has been reported in a case of monoallelic chronic macrothrombocytopenia without bleeding diathesis similar to our patient. Amino acid residues p.Cys20 and p.Cyc33 are highly conserved among divergent species and substitution of these amino acid residues appears to not be tolerated. Substitution of other cysteine amino acid residues in the extracellular domain of the GP1BA protein (p.Cys81 and p.Cys225) has also been reported in patients with biallelic BSS, suggesting that perturbation of cysteine amino acid residues is likely to affect protein structure and function. Conclusion:We think the p.Cys33Gly substitution found in our patient and her relatives is likely to be a primary cause of monoallelic GP1BA-associated macrothrombocytopenia. It is important to distinguish inherited macrothrombocytopenia from ITP in order to avoid unnecessary and potentially toxic treatment. Disclosures No relevant conflicts of interest to declare.