Amino Acid Mixture Research Articles

IR76b-expressing neurons in Drosophila melanogaster are necessary for associative reward learning of an amino acid mixture.

Learning where to find nutrients while at the same time avoiding toxic food is essential for survival of any animal. Using Drosophila melanogaster larvae as a study case, we investigate the role of gustatory sensory neurons expressing IR76b for associative learning of amino acids, the building blocks of proteins. We found surprising complexity in the neuronal underpinnings of sensing amino acids, and a functional division of sensory neurons. We found that the IR76b receptor is dispensable for amino acid learning, whereas the neurons expressing IR76b are specifically required for the rewarding but not the punishing effect of amino acids. This unexpected dissociation in neuronal processing of amino acids for different behavioural functions provides a study case for functional divisions of labour in gustatory systems.

Nitrogen and phosphorus uptake kinetics in cultures of two novel picoplankton groups responsible for a recent bloom event in a subtropical estuary (Indian River Lagoon, Florida)

IntroductionSuccessful management and mitigation of harmful algal blooms (HABs) requires an in-depth understanding of the physiology and nutrient utilization of the organisms responsible. We explored the preference of various nitrogen (N) and phosphorus (P) substrates by two novel groups of HAB-forming phytoplankton originating from the Indian River Lagoon (IRL), Florida: 1) a consortium of picocyanobacteria (Crocosphaera sp. and ‘Synechococcus’ sp.) and 2) ananochlorophyte (Picochlorum sp.).MethodsShort-term kinetic uptake experiments tested algal use and affinity for inorganic and organic N substrates (ammonium (NH4+), nitrate (NO3-), urea, and an amino acid (AA) mixture) through 15N and 13C isotope tracing into biomass.ResultsPicocyanobacteria exhibited Michaelis-Menten type uptake for the AA mixture only, while nanochlorophytes reached saturation for NH4+, the AA mixture, and urea at or below 25 µM-N. Both picocyanobacteria and nanochlorophyte cultures had highest affinity (Vmax/Ks) for NH4+ followed by the AA mixture and urea. Neither culture showed significant uptake of isotopically-labeled nitrate. Disappearance of glucose-6-phosphate (G6P) added to culture medium suggesting use of organic P by both cultures was confirmed by detection of alkaline phosphatase activity and the tracing of 13C-G6P into biomass.DiscussionTogether, our results suggest that these HAB-forming phytoplankton groups are able to use a variety of N and P sources including organic forms, and prefer reduced forms of N. These traits are likely favorable under conditions found in the IRL during periods of significant competition for low concentrations of inorganic nutrients. Bloom-forming phytoplankton are therefore able to subsist on organic or recycled forms of N and P that typically dominate the IRL nutrient pools.

Effect of polyamine precursors and antioxidants on growth and metabolism of salt-stressed barley

Background Salt stress, a significant environmental problem was studied in barley cultivars Giza 124 and Giza 119 at various stages (seedling, pre-flowering, and yield). This study aimed to investigate the impact of salt stress on these cultivars, examine the effects of polyamine precursors (arginine, methionine, and ornithine) on their response to salt stress, and assess the efficacy of antioxidants (glutathione and ascorbic acid) in alleviating the harmful effects of salt stress on barley plants. Methods Barley grains were germinated and subjected to salinity stress, with subsequent treatment using glutathione, ascorbic acid, or an amino acid mixture. Growth criteria, photosynthetic pigments, metabolites, antioxidant enzymes, mineral content, and polyamines were analyzed. Results The impact of 100Mm NaCl, with or without glutathione, ascorbic acid, or amino acid mixtures, on various physiological parameters in G124 and G119 were investigated. The levels of chlorophyll a, chlorophyll b, and carotenoids significantly varied under different treatments. For instance, chlorophyll a in G 124 exhibited a 23% reduction under salt stress compared to the control, while the addition of glutathione mitigated this effect, resulting in a 17% increase compared to the NaCl treatment. Similar trends were observed for chlorophyll b and carotenoids. At the yield stage, both cultivars demonstrated a significant decrease in the the weight of grains per plant under salinity, which was alleviated by the addition of ascorbic acid, glutathione, or amino acid mixtures. Conclusion The application of glutathione, ascorbic acid, or an amino acid mixture mitigated the adverse effects of salt stress on various parameters. The results highlight the potentail of these compounds in enhancing plant tolerance to salinity stress and offer insights into the physiological response of barley cultivars under adverse conditions.

Amino Acids Biostimulants and Protein Hydrolysates in Agricultural Sciences.

The effects of different types of biostimulants on crops include improving the visual quality of the final products, stimulating the immune systems of plants, inducing the biosynthesis of plant defensive biomolecules, removing heavy metals from contaminated soil, improving crop performance, reducing leaching, improving root development and seed germination, inducing tolerance to abiotic and biotic stressors, promoting crop establishment and increasing nutrient-use efficiency. Protein hydrolysates are mixtures of polypeptides and free amino acids resulting from enzymatic and chemical hydrolysis of agro-industrial protein by-products obtained from animal or plant origins, and they are able to alleviate environmental stress effects, improve growth, and promote crop productivity. Amino acids involve various advantages such as increased yield and yield components, increased nutrient assimilation and stress tolerance, and improved yield components and quality characteristics. They are generally achieved through chemical or enzymatic protein hydrolysis, with significant capabilities to influence the synthesis and activity of some enzymes, gene expression, and redox-homeostasis. Increased yield, yield components, and crop quality; improved and regulated oxidation-reduction process, photosynthesis, and physiological activities; decreased negative effects of toxic components; and improved anti-fungal activities of plants are just some of the more important benefits of the application of phenols and phenolic biostimulants. The aim of this manuscript is to survey the impacts of amino acids, different types of protein hydrolysates, phenols, and phenolic biostimulants on different plants by presenting case studies and successful paradigms in several horticultural and agricultural crops.

Differential local ordering of mixed crowders determines effective size and stability of ss-DNA capped gold nanoparticle.

Understanding the influence of a crowded intracellular environment on the structure and solvation of DNA functionalized gold nanoparticles (ss-DNA AuNP) is necessary for designing applications in nanomedicine. In this study, the effect of single (Gly, Ser, Lys) and mixture of amino acids (Gly+Ser, Gly+Lys, Ser+Lys) at crowded concentrations is examined on the structure of the ss-DNA AuNP using molecular dynamics simulations. Using the structural estimators such as pair correlation functions and ligand shell positional fluctuations, the solvation entropy is estimated. Combining the AuNP-solvent interaction energy with the solvation entropy estimates, the free energy of solvation of the AuNP in crowded solutions is computed. The solvation entropy favours the solvation free energy which becomes more favourable for larger effective size of AuNP in crowded solutions relative to that in water. The effective size of AuNP depends on the different propensity of the crowders to adsorb on Au surface, with the smallest crowder (Gly) having the highest propensity inducing the least effective AuNP size as compared to other single crowder solutions. In mixed crowded solutions of amino acids of variable size and chemistry, distinctive local adsorption of the crowders on the gold surface is observed that controls the additive or non-additive crowding effects which govern an increase (in Gly+Ser) or decrease (in Gly+Lys) in nanoparticle effective size respectively. The results shed light into the fundamental understanding of the influence of intracellular crowding on structure of ss-DNA AuNP and plausible employability of crowding as a tool to design programmable self-assembly of functionalized nanoparticles.

Pubertal origin of growth retardation in inborn errors of protein metabolism: A longitudinal cohort study

ObjectivesInherited amino-acid metabolism disorders (IAAMDs) require lifelong protein-restricted diet. We aimed to investigate: 1/ whether IAAMDs was associated with growth, pubertal, bone mineral apparent density (BMAD) or body composition impairments; 2/ associations linking height, amino-acid mixture (AAM), plasma amino-acids and IGF1 concentrations. DesignRetrospective longitudinal study of 213 patients with neonatal-onset urea cycle disorders (UCD,n = 77), organic aciduria (OA,n = 89), maple syrup urine disease (MSUD,n = 34), or tyrosinaemia type 1 (n = 13). MethodsWe collected growth parameters, pubertal status, BMAD, body composition, protein-intake, and IGF1 throughout growth. ResultsOverall final height (n = 69) was below target height (TH): −0.9(1.4) vs. -0.1(0.9) SD, p < 0.001. Final height was ≤ TH-2SD in 12 (21%) patients. Height ≤ − 2SD was more frequent during puberty than during early-infancy and pre-puberty: 23.5% vs. 6.9%, p = 0.002; and vs. 10.7%, p < 0.001. Pubertal delay was frequent (26.7%). Height (SD) was positively associated with isoleucine concentration: β, 0.008; 95%CI, 0.003 to 0.012; p = 0.001. In the pubertal subgroup, height (SD) was lower in patients with vs. without AAM supplementation: −1.22 (1.40) vs. -0.63 (1.46) (p = 0.02). In OA, height and median (IQR) isoleucine and valine concentrations(μmol/L) during puberty were lower in patients with vs. without AAM supplementation: −1.75 (1.30) vs. −0.33 (1.55) SD, p < 0.001; and 40 (23) vs. 60 (25) (p = 0.02) and 138 (92) vs. 191 (63) (p = 0.01), respectively. No correlation was found with IGF1. Lean-mass index was lower than fat-mass index: −2.03 (1.15) vs. -0.44 (0.89), p < 0.001. ConclusionsIn IAAMDs, growth retardation worsened during puberty which was delayed in all disease subgroups. Height seems linked to the disease, AAM composition and lower isoleucine concentration, independently of the GH-IGF1 pathway. We recommend close monitoring of diet during puberty.

Bioavailability of essential amino acids after ingestion of fortified biscuits with a mixture of essential amino acid in healthy subjects

Bioavailability of essential amino acids after ingestion of fortified biscuits with a mixture of essential amino acid in healthy subjects

Catalytic enantiospecific deuteration of complex amino acid mixtures with ruthenium nanoparticles

Hydrogen Isotope Exchange (HIE) of a mixture of amino acids has been studied with the purpose of producing deuterated proteins.

STABILITY PROPERTIES OF ALKALINE PROTEASES SOURCES AT DIFFERENT OPTIMUM CONDITIONS

– Alkaline proteases possess considerable industrial potential due to their biochemical diversity and wide applications in tannery and food industries, medicinal formulations, detergents and processes like waste treatment, silver recovery and resolution of amino acid mixtures. The genus Bacillus contains a number of industrially important species and approximately half of the present commercial production of bulk enzymes derives from the strains of Bacillus sp. These strains are specific producers of extracellular proteases and can be cultivated under extreme temperature and pH conditions to give rise to products that are, in turn, stable in a wide range of harsh environments.

Values for the Digestibility of Pea Protein Isolate or Casein Amino Acids Determined using the Dual Isotope Method Are Not Similar to Those Derived with the Standard Ileal Balance Method in Healthy Volunteers

BackgroundThe measurement of ileal amino acid (AA) digestibility is invasive and inappropriate when applied to vulnerable populations. The dual isotope method has been developed over the past 5 y as an alternative method. ObjectiveThe aim of this work was to compare the indispensable amino acid (IAA) digestibility values of 2 different proteins obtained using the dual isotope and the standard ileal balance methods in the same subjects. MethodsFifteen healthy adults completed the study. Over 4 h, they ingested 9 successive portions of mashed potatoes containing the test protein (pea protein or casein) labeled intrinsically with 15N and 2H, and a 13C-free AA mixture as a reference for the dual isotope method. Plasma was sampled regularly over the 8-h postprandial period, whereas the ileal digesta was collected continuously via a naso-ileal tube. Isotopic enrichments (15N and 13C) were measured in the digesta for the direct determination of ileal IAA digestibility, whereas plasma enrichments (2H and 13C) were measured to determine IAA digestibility using the dual isotope method. ResultsThe 4-h repeated meal procedure enabled the almost complete digestion of test proteins at 8 h and the attainment of a plasma isotopic plateau between 2.5 and 4 h. These conditions were necessary to perform the ileal balance and dual isotope methods simultaneously. For pea protein, the mean IAA digestibility was similar between the 2 methods, but significant differences (from 10% to 20%) were observed for individual IAA values. For casein, IAA digestibility was significantly lower with the dual isotope method for all the IAA analyzed. ConclusionsUnder our experimental conditions, the degree of agreement between the dual isotope and ileal balance methods varied among AAs and depended on the protein source. Further research is needed to validate the dual isotope method.This study was registered at clinicaltrials.gov as NCT04072770.

Plant testing with hemp and miscanthus to assess phytomanagement options including biostimulants and mycorrhizae on a metal-contaminated soil to provide biomass for sustainable biofuel production

The need of biofuels from biomass, including sustainable aviation fuel, without using agricultural land dedicated to food crops, is in constant demand. Strategies to intensify biomass production using mycorrhizal fungi, biostimulants and their combinations could be solutions for improving the cultivation of lignocellulosic plants but still lack well-established validation on metal-contaminated soils. This study aimed to assess the yield of Miscanthus x giganteus J.M. Greef & Deuter and Cannabis sativa L. grown on a metal-contaminated agricultural soil (11 mg Cd, 536 mg Pb and 955 mg Zn kg−1) amended with biostimulants and/or arbuscular mycorrhizal fungi, and the shoot Cd, Pb and Zn uptake. A pot trial was carried out with soil collected from a field near a former Pb/Zn smelter in France and six treatments: control (C), protein hydrolysate (a mixture of peptides and amino acids, PH), humic/fulvic acids (HFA), arbuscular mycorrhizae fungi (AMF), PH combined with AMF (PHxAMF), and HFA combined with AMF (HFAxAMF). Metal concentrations in the soil pore water (SPW), pH and electrical conductivity were measured over time. Miscanthus and hemp shoots were harvested on day 90. Both PH and PHxAMF treatments increased SPW Cd, Pb, and Zn concentrations (e.g. by 26, 1.9, and 22.9 times for miscanthus and 9.7, 4.7, and 19.3 times for hemp in the PH and PHxAMF treatments as compared to the control one, respectively). This led to phytotoxicity and reduced shoot yield for miscanthus. Conversely, HFA and HFAxAMF treatments decreased SPW Cd and Zn concentrations, increasing shoot yields for hemp and miscanthus. Shoot Cd, Pb, and Zn uptakes peaked for PH and PHxAMF hemp plants (in μg plant-1, Cd: 310–334, Pb: 34–38, and Zn: 232–309 for PHxAMF and PH, respectively), while lowest values occurred for PH miscanthus plants mainly due to low shoot yield. Overall, this study suggested that humic/fulvic acids can be an effective biostimulant for increasing shoot biomass production in a metal-contaminated soil. These results warrant further investigations of the HFAxAMF in field trials.

Эффективность различных терапевтических подходов в лечении детей с эозинофильным эзофагитом

Eosinophilic esophagitis (EoE) is a multifactorial disease characterized by variable clinical manifestations and varying responses to therapy, especially in pediatric patients. The purpose of this research was to analyze the results of EoE various treatment methods in children. Materials and methods used: a single-center retrospective cohort study conducted in 2020-2023 that included patients from 6 y/o to 17 years and 11 months old whose condition was assessed when verifying the EoE diagnosis and after prescribing therapy at least once. Symptoms of dysphagia were assessed using the Dysphagia Symptom Questionnaire, the endoscopic signs of EoE were recorded using the EREFS scoring system, and the number of eosinophils in biopsy samples of the mucous membrane (MM) of the esophagus was counted (at a magnification of 400) as well. Physical development was assessed using the WHO AnthroPlus application. Results: 18 patients were divided into 3 groups: G1 (n=5) of those who received monotherapy with topical glucocorticosteroids (tGCS), G2 (n=10) of those who received combination therapy with proton pump inhibitors (PPIs) and tGCS, and G3 (n=3) of those receiving dupilumab therapy. The three patients from G2 were prescribed with amino acid mixture as nutritional support. Statistically significant decrease in symptoms of dysphagia (p&lt;0.001), decrease in the total score on the EREFS as well as decrease in the peak number of eosinophils in biopsy specimens of the esophagus were detected after 8 to 12 weeks after the start of treatment in all patients. However, statistically insignificant deterioration in clinical and histological parameters (p=0.06 and 0.2, respectively) coupled with statistically significant increase in EREFS scores (p=0.02) were revealed during the second control esophagogastroduodenoscopies in patients from Groups 1 and 2. Dupilumab therapy was effective in all considered parameters. In addition to the regression in clinical symptoms, endoscopic and histological signs, there was a significant improvement in nutritional status detected on the background of the amino acid mixture in all patients. Signs of esophageal candidiasis were recorded during the long-term therapy with corticosteroids in a singles patient. Conclusion: the too early reduction of therapy in children with EoE happening on the background of signs of clinical and histological remission could lead to the disease relapse. Management of children with EoE requires regular monitoring of the disease activity and dietary therapy taking into consideration the individual characteristics of each patient with EoE.

Effect of Protein Concentrate Withdrawal and Reducing the Crude Protein in Diets and Supporting Them with a Mixtures of Essential Amino Acids on some Physiological Traits of Laying Hens

The study was conducted to show Effect of protein concentrate Withdrawal and reducing the crude Protein in diets and supporting them with a mixtures of essential amino acids on some physiological traits of laying hens. (128) laying hens, type Lohmann Brown, at the age of (21) weeks, was randomly distributed among 8 treatments, with 8 replications for each treatment, as each replication was carried out on (2) hen (16 chickens/treatment), And the experimental treatments were as follows: T1 control (standard diet) and T2 (a treatment devoid of protein concentration ), and treatments T3, T4, and T5 (in which the percentage of crude protein was reduced by 1% and add on a mixture of amino acids consisting of methionine, lysine, and threonine was added by 1, 1.5, and 2%, respectively), and treatments T6, T7, and T8 (in which the percentage of crude protein was reduced by 2%, and add on a mixture of amino acids consisting of methionine, lysine, and threonine was added by 1, 1.5, and 2%, respectively). The results showed that there were no significant differences between the treatments of the experiment, but it was noted that there was a significant superiority (P < 0.05) for the treatments of adding the mixture of amino acids in favor of the treatments T1 and T10 in terms of cholesterol, total protein and albumin, compared with the treatment of T1 and T2 control, as well as treatment recorded T1, T2 and T3 Highly significant (P<0.01) superiority in IgM and IgA traits. It can be concluded from this study that adding the mixture of amino acids by 1.5 and 2% and reducing the protein percentage by (1 and 2%) led to a significant improvement in some physiological characteristics compared with the control treatment

Effect of a Low-Protein Diet with Different Levels of Amino Acid Mixture in Laying Hens on their Performance and Some Qualitative Characteristics of Eggs

This study was conducted for the period from 1/1/2022 to 1/8/2022 (210 days), to study the effect of replacing the mixture of amino acids (methionine, lysine, and threonine) instead of the protein concentrate in the diets of laying hens that reduced crude protein by (1, 1.5, 2%) in some qualitative characteristics of eggs. In the study, (128) laying hens of the Lohmann Brown type were used, at the age of (21) weeks, preceded by two weeks of preparation for the herd. They were randomly distributed among 8 treatments, with 8 replications for each treatment, as each repetition includes (2) chickens (16 chickens/treatment). And the experimental treatments were as follows: T1 the control (standard diet), T2 (a treatment devoid of the protein concentrate), and the treatments T3, T4, and T5 (in which the percentage of crude protein was reduced by 1% and a mixture of amino acids consisting of methionine, lysine, and threonine was added by 1, 1.5, and 2%, respectively)., and treatments T6, T7, and T8 (in which the percentage of crude protein was reduced by 2% and a mixture of amino acids consisting of methionine, lysine, and threonine was added by 1, 1.5, and 2%, respectively). The results showed that there was a significant (P < 0.05) superiority for the treatments T1, T4, and T8 in yolk weight, yolk diameter, yolk relative weight, and yolk index at the middle of the experiment at the age of (21-32) weeks, while both were significantly superior (P < 0.05) From the coefficients T2, T9, T10 in the yolk weight, yolk height, yolk diameter, and the relative weight of the yolk in the last period of the experiment, The results showed a significant superiority (P < 0.05) for treatments T1, T8, and T10 when calculating the Albumin weight, Albumin height, Albumin diameter, and the relative weight of the egg, Treatments T2 and T3 were significantly (P<0.05) superior when measuring the weight of the eggshell, the relative weight of the eggshell, and the average thickness of the eggshell, compared with most of the experimental treatments. These results indicate that there is a qualitative improvement for some of the studied traits when adding the mixture of amino acids and reducing the percentage of total protein by 1.2% compared to the control group that does not contain amino acids.

Meal anabolic capacity, measured by either non- or compartmental analysis after pulse tracer administration, is not different between HMB or LEU added to an essential amino acid mixture in older adults

Meal anabolic capacity, measured by either non- or compartmental analysis after pulse tracer administration, is not different between HMB or LEU added to an essential amino acid mixture in older adults

Aqueous Extracts from Hemp Seeds as a New Weapon against Staphylococcus epidermidis Biofilms.

This study investigated the antibiofilm activity of water-soluble extracts obtained under different pH conditions from Cannabis sativa seeds and from previously defatted seeds. The chemical composition of the extracts, determined through GC-MS and NMR, revealed complex mixtures of fatty acids, monosaccharides, amino acids and glycerol in ratios depending on extraction pH. In particular, the extract obtained at pH 7 from defatted seeds (Ex7d) contained a larger variety of sugars compared to the others. Saturated and unsaturated fatty acids were found in all of the analysed extracts, but linoleic acid (C18:2) was detected only in the extracts obtained at pH 7 and pH 10. The extracts did not show cytotoxicity to HaCaT cells and significantly inhibited the formation of Staphylococcus epidermidis biofilms. The exception was the extract obtained at pH 10, which appeared to be less active. Ex7d showed the highest antibiofilm activity, i.e., around 90%. Ex7d was further fractionated by HPLC, and the antibiofilm activity of all fractions was evaluated. The 2D-NMR analysis highlighted that the most active fraction was largely composed of glycerolipids. This evidence suggested that these molecules are probably responsible for the observed antibiofilm effect but does not exclude a possible synergistic contribution by the other components.

Amino acid supplementation during the adaptation period did not affect the standardized ileal digestibility of amino acids in corn and soybean meal fed to pigs.

The objective was to determine the influence of amino acid (AA) supplementation during the adaptation period on the ileal digestibility of crude protein and AA in corn and soybean meal (SBM) fed to pigs. Six barrows with an initial body weight of 30.9±2.6 kg fitted with a T-cannula at the distal ileum were assigned to a 6×6 Latin square design with 6 dietary treatments and 6 periods. Two experimental diets contained corn or SBM as the sole AA source and an N-free diet was additionally prepared. For AA supplementation groups, an AA mixture consisted of Gly, Lys, Met, Thr, Trp, Ile, Val, His, and Phe was added to the corn diet and the N-free diet at the expense of cornstarch, and an AA mixture of Lys, Met, and Thr was added to the SBM diet. All diets contained 0.5% of chromic oxide. The 6 experimental diets were fed to the pigs for four and half days, and the 3 diets containing an AA mixture were switched to the respective diets without AA mixture during the following two and half days. Ileal digesta were collected on days 6 and 7. The addition of an AA mixture during the adaptation period increased apparent ileal digestibility of Arg and Trp in corn (p<0.05) but did not affect that in SBM. The addition of an AA mixture during the adaptation period increased apparent ileal digestibility of Pro and Gly regardless of feed ingredient (p<0.05) but did not affect that of other AA. All AA except Pro in corn and SBM were unaffected by the addition of the AA mixture during the adaptation period. The addition of amino acids to a low-protein diet during the adaptation period does not affect the standardized ileal digestibility of indispensable amino acids in pigs.

Synergistic Effect of Charged Amino Acids on the Stability and Fibril Formation of Lysozyme

AbstractOsmolytes alter the stability and aggregation of proteins. The effect of mixture of osmolytes is generally not a simple additive of their individual effects. Here, we examine the effect of different mixtures of charged amino acids (AAs) on the stability and fibrillation of lysozyme. Arg, Asp and Glu induce three‐state unfolding. The addition of Lys, Asp and Glu increases the thermal stability of lysozyme, whereas Arg does not alter the stability. The mixture of AAs destabilizes the intermediate, but the overall stability of lysozyme is increased. Arg with other AAs in the ratio of 1 : 0.5 and 1 : 1, and the equimolar ratio of Glu+Asp synergistically increases the stability, whereas the other mixtures counteract the stabilizing effects of each other. The apparent time taken for fibrillation is reduced with lower concentrations of Arg (≤0.75 M) and Glu (0.25 M) and at higher concentrations of Lys (1 M). In the mixed AAs, Arg and Lys with other AAs, and 1 : 1 ratio of Glu+Asp synergistically increases the fibrillation time. These observations suggest that Arg induces more synergistic stabilization and the presence of basic AAs in the mixture increases the fibrillation time compared to acidic AAs which show synergy only at equimolar concentrations.

Dietary Amino Acid Source Elicits Sex-Specific Metabolic Response to Diet-Induced NAFLD in Mice.

Non-alcoholic fatty liver disease (NAFLD) is a sexually dimorphic disease influenced by dietary factors. Here, the metabolic and hepatic effects of dietary amino acid (AA) source is assessed in Western diet (WD)-induced NAFLD in male and female mice. The AA source is either casein or a free AA mixture mimicking the composition of casein. As expected, males fed a casein-based WD display glucose intolerance, fasting hyperglycemia, and insulin-resistance and develop NAFLD associated with changes in hepatic gene expression and microbiota dysbiosis. In contrast, males fed the AA-based WD show no steatosis, a similar gene expression profile as males fed a control diet, and a distinct microbiota composition compared to males fed a casein-based WD. Females are protected against WD-induced liver damage, hepatic gene expression, and gut microbiota changes regardless of the AA source. Free dietary AA intake prevents the unhealthy metabolic outcomes of a WD preferentially in male mice.

The role of dopamine in visual imagery-An experimental pharmacological study.

Mental imagery enables people to simulate experiences in their minds without the presence of an external stimulus. The underlying biochemical mechanisms are poorly understood but there is vague evidence that dopamine may play a significant role. A better understanding at the biochemical level could help to unravel the mechanisms of mental imagery and related phenomena such as aphantasia (= lack of voluntary mental imagery), but also opens up possibilities for interventions to enhance or restore mental imagery. To test the hypothesis that acute dopamine depletion leads to a decrease in the strength of mental imagery, N = 22 male participants will be administered an amino acid mixture containing branched-chain amino acids (BCAAs) and tryptophan (TRP) to transiently reduce dopamine synthesis and further N = 22 male participants will receive a placebo. Plasma prolactin (PRL) levels are determined as a peripheral marker of brain dopamine function. The strength of mental imagery will be measured before and after ingestion of the BCAA/TRP mixture using the method of mental imagery priming. Additional exploratory analyses will use genetic data to investigate possible effects of variations on dopaminergic gene loci (e.g., DAT1) on dopamine levels and strength of mental imagery. The results show […].