The Effect of Noise in Raman Spectra on the Reconstruction of the Concentration of Amino Acids in the Mixture by Multivariate Curve Resolution (MCR) Analysis

Changes in the concentration of free amino acids in biological tissues is a sign of impaired protein metabolism in patients with cancer. Recently, Raman spectroscopy has been used for early diagnostics of oncological diseases. The concentrations of individual components of biological tissue (for instance, the concentrations of amino acids) can be obtained by decomposing the tissue Raman spectrum. This study was designed to evaluate the effect of noise in the Raman spectra of individual amino acids on the result of the decomposition of the spectra of an amino acid mixture. As a decomposition method, we used Multivariate Curve Resolution-Alternating Least Squares (MCR–ALS) analysis and investigate experimental Raman spectra of amino acids and mathematically simulated Raman spectra of amino acid mixtures. Noise with different signal-to-noise ratios (SNR) was artificially added to both the experimental spectra of pure amino acids and the spectra of the mixtures. Concentration values for each amino acid obtained as a result of applying the MCR–ALS analysis have been compared with the corresponding true values and the correlation coefficients have been calculated. The results show a less pronounced negative effect of noise in the case when the spectra of pure amino acids (which were used as a basis for the MCR–ALS analysis) are noisy, and a more pronounced negative effect when the spectrum of the mixture is noisy. The accuracy of reconstruction of an amino acid is also negatively affected by strong background fluorescence in the amino acid spectrum. Moreover, the results indicate that using the basis spectra with a high SNR (SNR = 5) makes it possible to successfully estimate the amino acid concentrations in a mixture even when the Raman spectrum of the mixture is noisy and has a low SNR (SNR < 5).

Influence of Dietary Supplementation with an Amino Acid Mixture on Inflammatory Markers, Immune Status and Serum Proteome in LPS-Challenged Weaned Piglets

In order to investigate the effect of a dietary amino acid mixture supplementation in lipopolysaccharide (LPS)-challenged weaned piglets, twenty-seven 28-day-old (8.2 ± 1.0 kg) newly weaned piglets were randomly allocated to one of three experimental treatments for five weeks. Diet 1: a CTRL treatment. Diet 2: an LPS treatment, where piglets were intraperitoneally administered LPS (25 μg/kg) on day 7. Diet 3: an LPS+MIX treatment, where piglets were intraperitoneally administered LPS on day 7 and fed a diet supplemented with a mixture of 0.3% of arginine, branched-chain amino acids (leucine, valine, and isoleucine), and cystine (MIX). Blood samples were drawn on day 10 and day 35, and serum was analysed for selected chemical parameters and proteomics. The LPS and LPS+MIX groups exhibited an increase in haptoglobin concentrations on day 10. The LPS group showed an increased cortisol concentration, while this concentration was reduced in the LPS+MIX group compared to the control group. Similarly, the LPS+MIX group showed a decreased haptoglobin concentration on day 35 compared to the two other groups. Immunoglobulin concentrations were affected by treatments. Indeed, on day 10, the concentrations of IgG and IgM were decreased by the LPS challenge, as illustrated by the lower concentrations of these two immunoglobulins in the LPS group compared to the control group. In addition, the supplementation with the amino acid mixture in the LPS+MIX further decreased IgG and increased IgM concentrations compared to the LPS group. Although a proteomics approach did not reveal important alterations in the protein profile in response to treatments, LPS-challenged piglets had an increase in proteins linked to the immune response, when compared to piglets supplemented with the amino acid mixture. Overall, data indicate that LPS-challenged piglets supplemented with this amino acid mixture are more protected against the detrimental effects of LPS.

Homocystinuria patient and caregiver survey: experiences of diagnosis and patient satisfaction

Background The main genetic causes of homocystinuria are cystathionine beta-synthase (CBS) deficiency and the remethylation defects. Many patients present in childhood but milder forms may present later in life. Some countries have newborn screening programs for the homocystinurias but these do not detect all patients. Results HCU Network Australia is one of the very few support groups for patients with homocystinurias. Here we report the results of its survey of 143 patients and caregivers from 22 countries, evaluating current diagnostic pathways and management for the homocystinurias. Most (110) of the responses related to patients with CBS deficiency. The diagnosis was made by newborn screening in 20% of patients and in 50% of the others within 1 year of the initial symptom but in 12.5% it took over 15 years. The delay was attributed mainly to ignorance of the disease. Physicians need to learn to measure homocysteine concentrations in children with neurodevelopmental problems, and in patients with heterogeneous symptoms such as thromboembolism, dislocation of the optic lens, haemolytic uraemic syndrome, and psychiatric disease. Even when the diagnosis is made, the way it is communicated is sometimes poor. Early-onset CBS deficiency usually requires a low-protein diet with amino acid supplements. More than a third of the participants reported problems with the availability or cost of treatment. Only half of the patients always took their amino acid mixture. In contrast, good adherence to the protein restriction was reported in 98% but 80% said it was hard, time-consuming and caused unhappiness. Conclusions There is often a long delay in diagnosing the homocystinurias unless this is achieved by newborn screening; this survey also highlights problems with the availability and cost of treatment and the palatability of protein substitutes.

Spontaneous emergence of membrane-forming protoamphiphiles from a lipid-amino acid mixture under wet-dry cycles

Dynamic interplay between peptide synthesis and membrane assembly would have been crucial for the emergence of protocells on the prebiotic Earth. However, the effect of membrane-forming amphiphiles on peptide synthesis,...

Spontaneous Emergence of Membrane-Forming Protoamphiphiles from a Lipid-Amino Acid Mixture Under Wet-Dry Cycles

<p>The prelude to the origin of cellular life on Earth would have involved a fundamental step, that of protocell formation. This involves the coming together of two crucial processes; abiotic synthesis of informational and catalytic polymers, and the assembly of membrane compartments. Mutual interactions between these processes would have likely affected the emergence and early stages of protocell evolution. Previous investigations have predominantly focused on cooperative interactions, often neglecting any competitive behavior that might ensue as ‘counterproductive cross-talk’. However, in a realistic scenario, both cooperative and competitive reactions would have occurred simultaneously in a complex prebiotic soup, generating a plethora of chemical species with their own prebiotic implications. In this study, we followed a systematic and unbiased approach to explore this interdependence. We used a lipid-amino acid system to demonstrate the above-mentioned phenomenon wherein we investigated the effect of a membrane-forming amphiphile on peptide synthesis, under prebiotically plausible conditions. </p><p><br></p> <p>Interestingly, our study shows the formation of a hitherto unobserved reaction product that could have played a significant role during the emergence of life on the early Earth. We do show that peptide synthesis occurs but with a decrease in the yield. This is due to another concurrent and competing reaction, wherein an amino acid covalently interacts with a phospholipid to generate new amphiphilic species called N-acyl amino acids (NAAs) via an ester-amide exchange process. These NAAs are thermostable and, hence, persistent even at high temperatures. Furthermore, this protoamphiphile is also able to self-assemble into vesicles at acidic pH. <i>Au contraire</i>, fatty acids, a widely accepted constituent of prebiotic compartments, have been shown to generate vesicles only at neutral to alkaline pH. Thus, NAAs could have had a selective advantage over fatty acids to form thermostable protocell compartments under acidic geothermal pool-like conditions, a niche that has gained prominence as one of the important geological settings where life could have originated. Our study underlines the importance of an unbiased exploration of the complex interactions between prebiotic processes, which could potentially open new avenues to solving the origin of life conundrum. </p> <p> </p>

Spontaneous Emergence of Membrane-Forming Protoamphiphiles from a Lipid-Amino Acid Mixture Under Wet-Dry Cycles

<p>The prelude to the origin of cellular life on Earth would have involved a fundamental step, that of protocell formation. This involves the coming together of two crucial processes; abiotic synthesis of informational and catalytic polymers, and the assembly of membrane compartments. Mutual interactions between these processes would have likely affected the emergence and early stages of protocell evolution. Previous investigations have predominantly focused on cooperative interactions, often neglecting any competitive behavior that might ensue as ‘counterproductive cross-talk’. However, in a realistic scenario, both cooperative and competitive reactions would have occurred simultaneously in a complex prebiotic soup, generating a plethora of chemical species with their own prebiotic implications. In this study, we followed a systematic and unbiased approach to explore this interdependence. We used a lipid-amino acid system to demonstrate the above-mentioned phenomenon wherein we investigated the effect of a membrane-forming amphiphile on peptide synthesis, under prebiotically plausible conditions. </p><p><br></p> <p>Interestingly, our study shows the formation of a hitherto unobserved reaction product that could have played a significant role during the emergence of life on the early Earth. We do show that peptide synthesis occurs but with a decrease in the yield. This is due to another concurrent and competing reaction, wherein an amino acid covalently interacts with a phospholipid to generate new amphiphilic species called N-acyl amino acids (NAAs) via an ester-amide exchange process. These NAAs are thermostable and, hence, persistent even at high temperatures. Furthermore, this protoamphiphile is also able to self-assemble into vesicles at acidic pH. <i>Au contraire</i>, fatty acids, a widely accepted constituent of prebiotic compartments, have been shown to generate vesicles only at neutral to alkaline pH. Thus, NAAs could have had a selective advantage over fatty acids to form thermostable protocell compartments under acidic geothermal pool-like conditions, a niche that has gained prominence as one of the important geological settings where life could have originated. Our study underlines the importance of an unbiased exploration of the complex interactions between prebiotic processes, which could potentially open new avenues to solving the origin of life conundrum. </p> <p> </p>

Experimental evidence on the efficacy of two new metabolic modulators on mitochondrial biogenesis and function in mouse cardiomyocytes

Proper maintenance of mitochondrial homeostasis is essential for cell health, and mitochondrial dysfunction underlies several metabolic and heart diseases. Stimulation of mitochondrial biogenesis represents a valuable therapeutic tool for the prevention and treatment of disorders characterized by a deficit in energy metabolism. The present study aimed to potentiate the mitochondrial biogenetic efficacy of an amino acid (AA) mixture, enriched in branched-chain amino acids (BCAAs), which we previously showed to boost mitochondrial biogenesis, leading to life span extension and reducing of muscle and liver damage. Hence, we designed and studied several innovative mixtures. Here, we report on two new AA formulas, α5 and E7, created on the BCAA-enriched amino acid mixture (BCAAem) template and enriched with Krebs cycle substrates, including succinate, malate, and citrate. Cardiomyocytes in culture exposed to either mixture showed increased mitochondrial DNA amount, mitochondrial biogenesis markers, and oxygen consump-tion. Furthermore, α5 and E7 also increased the expression of BCAA catabolic genes. Most importantly, all of these effects of α5 and E7 were more pronounced than those observed with BCAAem, confirming the higher mitochondrial biogenesis potential of these new formulas. Therefore, α5 and E7 could represent a more efficient tool for the nutritional treatment of diseases in which energy production is defective.