Amino Acid Fraction Research Articles

A new technique to study nutrient flow in host-parasite systems by carbon stable isotope analysis of amino acids and glucose

Stable isotope analysis of individual compounds is emerging as a powerful tool to study nutrient origin and conversion in host-parasite systems. We measured the carbon isotope composition of amino acids and glucose in the cestode Schistocephalus solidus and in liver and muscle tissues of its second intermediate host, the three-spined stickleback (Gasterosteus aculeatus), over the course of 90 days in a controlled infection experiment. Similar linear regressions of δ13C values over time and low trophic fractionation of essential amino acids indicate that the parasite assimilates nutrients from sources closely connected to the liver metabolism of its host. Biosynthesis of glucose in the parasite might occur from the glucogenic precursors alanine, asparagine and glutamine and with an isotope fractionation of − 2 to – 3 ‰ from enzymatic reactions, while trophic fractionation of glycine, serine and threonine could be interpreted as extensive nutrient conversion to fuel parasitic growth through one-carbon metabolism. Trophic fractionation of amino acids between sticklebacks and their diets was slightly increased in infected compared to uninfected individuals, which could be caused by increased (immune-) metabolic activities due to parasitic infection. Our results show that compound-specific stable isotope analysis has unique opportunities to study host and parasite physiology.

Evidence of gastrointestinal sensing and gut-brain communication in rainbow trout (Oncorhynchus mykiss) in response to the aqueous extract of fishmeal and its free amino acid fraction

Using rainbow trout (Oncorhynchus mykiss) as a model, we aimed to obtain information about the gastrointestinal tract (GIT) amino acid sensing capacity and hormone production along regions of the GIT, in response to proline (Pro), to a solution of free amino acids (FAA) mimicking the composition of a fishmeal (FM) aqueous extract (FM-FAA), or to the whole FM aqueous extract (FM-AQE). In addition, we evaluated central responses (in hypothalamus) in mechanisms regulating food intake, 2 h following intragastric administration of these treatments. The presence of Pro in the GIT elicited changes in amino acid sensing systems and in the production of GIT hormones, especially in the more proximal regions in parallel with an anorectic response in hypothalamus. The intragastric administration of FM-AQE induced increased production of the anorectic hormones peptide tyrosine-tyrosine (PYY) and cholecystokinin (CCK) that occurred 20 min post-treatment in the proximal and middle intestine of this treatment. These changes occurred in parallel with an anorectic response in the hypothalamus 2 h post-treatment. The treatment with FM-FAA elicited a comparable anorectic response in the hypothalamus at 2 h post-treatment, which was associated however with a more complex response in the GIT. This included a comparable increased production of the anorectic hormones PYY and CCK in the proximal and middle intestine, but also a decreased production of the orexigenic hormone ghrelin (GHRL) in the stomach, 20 min after FM-FAA administration. These effects were also accompanied by some changes in parameters related to amino acid sensing systems mediated by receptors, which were not observed in the FM-AQE treatment. Overall, results indicate that all treatments elicited a response in elements of gut sensing mechanisms and gut-brain axis, despite important differences in the specific genes (likely having different substrate specificities), GIT areas and times in which responses were observed.

Effects of metabiotic Bacillus subtilis for microbiocenosis formation in early-weaned piglets

This paper discusses the results of research related to cultivation of the probiotic microorganism B. subtilis on a grain-based nutrient medium of naked oat (Avena nuda) and studies the possibility of using metabolites as a liquid dietary supplement to correct microbiocenosis gastrointestinal tract disorders in early-weaned piglets. The weight fraction of proteinogenic amino acids in the experimental probiotic suspensions was determined by means of capillary electrophoresis. The metabolic activity of Bacillus subtilis DSM-32424 strain was studied on both sprouted as well as non-sprouted naked oat (Avena nuda) ‘Nemchinovsky’ variety grain-based nutrient medium. It was proved that the maximum microbial count reached 4.9×107 CFU/cm3 on the 6th day of cultivation on the medium based on sprouted naked oat. The use of dietary supplement based on Bacillus subtilis DSM-32424 strain in amount of at least 1×109 CFU/pig had a positive impact in terms of the formation of microbiocenosis in animals at the time of transferring piglets to plant diet.

PAWG pilot study on quantification of SARS-CoV-2 monoclonal antibody - Part 2

Main textUnder the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P216, was coordinated by the Chinese National Institute of Metrology (NIM), National Research Council of Canada (NRC) and the Bureau International des Poids et Mesures (BIPM).The global coronavirus pandemic has also led to increased focus on antibody quantitation methods. IgG are among the immunoglobulins produced by the immune system to provide protection against SARS-CoV-2. Anti-SARS-CoV-2 IgG can therefore be detected in samples from affected patients. Antibody tests can show whether a person has been exposed to SARS-CoV-2, and whether or not they potentially show lasting immunity to the disease. With the constant spread of the virus and the high pressure of re-opening economies, antibody testing played a critical role in the fight against COVID-19 by helping healthcare professionals to identify individuals who have developed an immune response, either via vaccination or exposure to the virus. Many countries have launched large-scale antibody testing for COVID-19. The development of measurement standards for the antibody detection of SARS-CoV-2 is critically important to deal with the challenges of the COVID-19 pandemic. In this study, the SARS-CoV-2 monoclonal antibody is being used as a model system to build capacity in methods that can be used in antibody quantification.The purpose of this pilot study was to develop measurement capabilities for larger proteins using a recombinant humanized IgG monoclonal antibody against Spike glycoprotein of SARS-CoV-2 (Anti-S IgG mAb) in solution. A Final Report on the first round of CCQM-P216 PAWG Pilot Study on Quantification of SARS-CoV-2 Monoclonal Antibody - Part 1 focusing on the assessment of both mass fraction determinations of different AAs in the material and mass fraction determinations of proteotypic peptides belonging to the constant region of the mAb has already been published in Metrologia. The present Final Report on the second round of CCQM-P216 - Part 2 was designed to investigate optional methods for the characterization of Anti-S IgG mAb in solution for the assessment of size heterogeneity purity determinations, mass fraction measurements of SARS-CoV-2 monoclonal antibody in the material by UV-VIS spectrophotometry, mass fraction measurements of proteotypic peptides belonging to the variable region of the mAb and mass fraction measurements of monomeric mAb in the material. Six Metrology Institutes or Designated Institutes and the BIPM participated in the second phase of the pilot study (Part 2).Acceptable agreement between all laboratories was for the assessment of size heterogeneity of the anti-S IgG mAb material. For example, a reference value with its corresponding expanded uncertainties of (99.48 ± 0.49) % has been obtained for the monomer. Good between laboratories for UV-VIS spectrophotometric analysis at a pre-agreed wavelength of 280 nm was obtained with individual relative expanded uncertainties from 2.8 % to 15.5 % and a mass concentration reference value and corresponding expanded uncertainty of (500.8 ± 15.4) mg/L.Mass fraction assignments of the target proteotypic peptide YSPSFQGQVTISADK in the variable region of the anti-S IgG mAb material by NIM and BIPM resulted in a reference value and corresponding expanded uncertainty of (9.8 ± 2.0) mg/kg.Both NIM and BIPM have provided estimates for the mass fraction of monomeric mAb in the material with individual relative expanded uncertainties of 4.3 % and 4.1 %, respectively. A mass fraction reference value and corresponding expanded uncertainty of (411 ± 88) mg/kg was calculated by applying an 'excess-variance' approach for the monomeric mAb mass fraction.In addition, a post-hoc assessment of the monomeric mAb mass fraction from the subset of that produced both amino acid and proteotypic peptide-based mass fraction results and SEC measurements during the 1st and present study round provided more detailed information. A reference value and its expanded uncertainty for the mass fraction of monomeric mAb in the anti-S IgG mAb material was calculated to be (434.3 ± 11.9) mg/kg applying an 'excess-variance' approach.The level of agreement was not significantly poorer than that achieved in previous studies with smaller or less complex proteins. The two-stage pilot study was a big step forward to build and improve capacity within NMIs/DIs to undertake future key comparisons in the field of mass fraction determinations of antibodies and other large proteins.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparative Analysis of the Amino Acid Composition of Beverages Based on Plant Raw Materials and Cow's Milk

Knowledge of the peculiarities of technological processes for the production of cow's milk analogues, optimal parameters for production, the chemical composition of raw materials and the resulting finished product, in particular the amino acid composition, plays an essential role in the development of new types of functional products, improvement of their stability, taste, and nutritional properties, and allows them to be enriched with additional components through various modifications. The purpose of the study is to compare the amino acid composition and balance of amino acids of various types of beverages based on plant raw materials: almond, rice and coconut, oatmeal with respect to the amino acid composition of cow's milk protein. The following methods were used: capillary electrophoresis – to determine the amino acid composition of the protein in analogues of milk and cow's milk, mathematical – to calculate the amino acid score and utility coefficient. The composition, organoleptic quality indicators, main technological stages, and safety of production of plant-based analogues of animal milk are presented. Three types of plant-based beverages were used for the study: almond with a mass fraction of fat of 1.5%; oatmeal with a mass fraction of fat of 2.5%; rice and coconut with a mass fraction of fat of 1.8%; and cow's milk with a mass fraction of fat of 2.5%. A comparative estimate of the mass fraction of amino acids valine, isoleucine, leucine, lysine, methionine, threonine, and phenylalanine in the protein of beverages based on plant raw materials is presented relative to the mass fraction of amino acids in the milk protein, and the reference protein. The limiting amino acid in the protein composition of the studied analogues of cow's milk is methionine. The highest amino acid protein scores were observed in oatmeal drink; however, they did not exceed those of pasteurised milk. To assess the balance of the amino acid composition, the utility coefficient was determined. The findings are of practical importance, because they can be used in the production of functional products, in particular, analogues of cow's milk, to improve the composition, increase biological value, and enrichment with nutrients and additional components

HPAEC-PAD analysis for determination of the amino acid profiles in protein fractions from oat flour combined with correction of amino acid loss during hydrolysis

Current derivatization-dependent approaches for amino acid composition analysis of cereal proteins have significant variability due to lack of direct analysis opportunities and loss of amino acids during protein-hydrolysis. To tackle these drawbacks, a novel direct, derivatization-free approach was successfully introduced, using HPAEC-PAD, and applied for analysis of hydrolyzed defatted oat flour and extracted flour protein fractions. The approach ensured reliable detection of amino acids, including L-tryptophan, as well as oxidation products of L-cysteine and L-methionine. A time course study, analysed by nonlinear least-square regression to determine rates of hydrolysis and loss of each amino acid, allowed comparison of the original mass fraction (AA0) of the respective amino acid in the oat flour mixture with the mass fraction obtained after 24 h hydrolysis (AA24). The difference between (AA0) and (AA24) was less than 0.05%, except for L-arginine (0.61%), glycine (0.14%), L-isoleucine (0.27%), and L-tryptophan (0.17%). The (AA0)s obtained corresponded to literature-data, and fitted with the amino acid composition estimated from deduced proteins encoded in the oat genome, except for L-arginine (27%) and L-glutamic acid/L-glutamine (10%). The amino acid composition estimation from sequence data indirectly confirmed that the high presence of L-arginine observed was a result of co-elution with unknown flour components.

Testing the effect of oxidizing pre-treatments on amino acids in benthic and planktic foraminifera tests

Amino acid racemization (AAR) is a geochronological method that uses the ratio of D- to L-configurations in optically active amino acids from carbonate fossils to determine the time elapsed since the death of an organism. Although AAR techniques have been widely applied to foraminiferal tests, there have been limited dedicated assessments of the potential of isolating a bleach-resistant, intra-crystalline fraction of proteins to improve the reliability of AAR in this biomineral system. In this study, we evaluate the effect of two oxidative pre-treatments (hydrogen peroxide and bleach) on amino acid concentrations and D/L values in sub-modern benthic foraminifers ( Ammonia spp. and Haynesina germanica ) and well-preserved mid Holocene and mid Pleistocene planktic foraminifers ( Pulleniatina obliquiloculata , Globorotalia truncatulinoides , and Globorotalia tumida ). The oxidative pre-treatments successfully reduced the amino acid content of the foraminiferal tests to a residual fraction, and with the exception of Ammonia spp., neither pre-treatment substantially affected the relative proportion of individual amino acids. The bleaching pre-treatment does not consistently alter D/L values when compared to peroxide pre-treatment, but it does tend to reduce the subsample variability in D/L values, albeit only to a small degree in an inconsistent fashion. Therefore, we recommend that a relatively weak oxidative pre-treatment with 3% hydrogen peroxide is sufficient for foraminifera-based AAR applications. • Intra-crystalline fraction of amino acids in foraminiferal tests was isolated using oxidative pre-treatments • Difference in concentration between the inter- and intra-crystalline fractions of amino acids decreases with increased sample age • No consistent improvement in intra-sample variability when foraminiferal tests are treated with bleach • Pretreating foraminiferal tests with peroxide rather than bleach is recommended

Effects of Primary Processing and Pre-Salting of Baltic Herring on Contribution of Digestive Proteases in Marinating Process

The low-technological quality of herring caught during the feeding season makes it impossible to achieve full ripeness of the meat in marinades. One solution may be to assist ripening using herring digestive tract proteases. Therefore, whole herring, headed herring and fillets were marinated for 2–14 days using the German (direct) and Danish (pre-salted) methods. The results showed that the mass of marinades from fillets was lower than from herring with intestines and correlated strongly with salt concentration in the Danish method, in contrast to the German method. Marinades from whole and headed herring had significantly higher trypsin, chymotrypsin, carboxypeptidase-A and cathepsin activities than marinated fillets. The herring marinated with viscera had 2–3 times higher non-protein nitrogen, peptide and amino acid fractions, as well as ripened 3 days faster than the marinated fillets. After 2 weeks of marinating, the fillets did not achieve full ripeness of the meat, unlike marinades made from whole and headed herring. The pre-salting stage in the Danish method significantly reduced cathepsin D activity by the tenth day of marinating, which was compensated by digestive proteases only in the case of whole or headed herring. The digestive proteases activity in the fillets was too low to achieve the same effect. Sensory evaluation of texture and hardness-TPA correlated strongly with several proteases in whole herring marinades, in contrast to a weak correlation with only one protease when marinating fillets. Marinating with intestines makes it possible to produce marinades faster, more efficiently and with higher sensory quality from herring of low-technological quality.

Metabolic Remodeling with Hepatosteatosis Induced Vascular Oxidative Stress in Hepatic ERK2 Deficiency Mice with High Fat Diets.

We previously demonstrated the marked hepatosteatosis and endothelial dysfunction in hepatocyte-specific ERK2 knockout mice (LE2KO) with a high-fat/high-sucrose diet (HFHSD), but detailed metabolic changes and the characteristics in insulin-sensitive organs were not tested. This study aimed to characterize metabolic remodeling with changes in insulin-sensitive organs, which could induce endothelial dysfunction in HFHSD-LE2KO. The serum glucose and fatty acid (FA) were modestly higher in HFHSD-LE2KO than HFHSD-Control. FA synthesis genes were up-regulated, which was associated with the decreased phosphorylation of AMPK and ACC, and with the up-regulation of SREBP-1 in the liver from HFHSD-LE2KO. In FA and amino acids fraction analysis, arachidonic acid/eicosapentaenoic acid ratio, L-ornithine/arginine ratio, asymmetric dimethylarginine and homocysteine levels were elevated in HFHSD-LE2KO. Insulin-induced phosphorylation of AKT was blunted in skeletal muscle. Serum leptin and IL-1β were elevated, and serum adiponectin was decreased with the enlargement of epididymal adipocytes. Finally, the enhanced superoxide levels in the aorta, which were blunted with CCCP, apocynin, and tempol, were observed in HFHSD-LE2KO. A pre-incubation of aortic rings with tempol improved endothelial dysfunction in HFHSD-LE2KO. HFHSD-LE2KO revealed an acceleration of FA synthesis in the liver leading to insulin resistance in skeletal muscle and the enlargement of visceral adipocytes. Global metabolic remodeling such as changes in arginine metabolism, ω3/ω6 ratio, and adipocytokines, could affect the vascular oxidative stress and endothelial dysfunction in HFHSD-LE2KO.

Insights into amino acid fractionation and incorporation by compound-specific carbon isotope analysis of three-spined sticklebacks

Interpretation of stable isotope data is of upmost importance in ecology to build sound models for the study of animal diets, migration patterns and physiology. However, our understanding of stable isotope fractionation and incorporation into consumer tissues is still limited. We therefore measured the δ13C values of individual amino acids over time from muscle and liver tissue of three-spined sticklebacks (Gasterosteus aculeatus) on a high protein diet. The δ13C values of amino acids in the liver quickly responded to small shifts of under ± 2.0‰ in dietary stable isotope compositions on 30-day intervals. We found on average no trophic fractionation in pooled essential (muscle, liver) and non-essential (muscle) amino acids. Negative Δδ13C values of − 0.7 ± 1.3‰ were observed for pooled non-essential (liver) amino acids and might indicate biosynthesis from small amounts of dietary lipids. Trophic fractionation of individual amino acids is reported and discussed, including unusual Δδ13C values of over + 4.9 ± 1.4‰ for histidine. Arginine and lysine showed the lowest trophic fractionation on individual sampling days and might be useful proxies for dietary sources on short time scales. We suggest further investigations using isotopically enriched materials to facilitate the correct interpretation of ecological field data.

Biological aspects of cultivation and application of active metabolites of B. subtilis probiotic

Relevance. In modern research, the topic of metabiotics is considered as one of the current directions in the development of probiotics, in the future — as a new class of metabiotics. The article presents the results of studies during the cultivation of the probiotic microorganism B. subtilis in a grain nutrient medium from naked oats, and a scientific and practical substantiation of an experimental probiotic suspension during the formation of microbiocenosis and metabolism of the gastrointestinal tract in early weaning piglets.Methods. As the basis of nutrient media for obtaining metabolites of the probiotic culture of Bacillus subtilis, sprouted and non-sprouted oat grains of the naked variety Nemchinovsky were used at the rate of 100 g of crushed raw material per 3 l of water. The mass fraction of proteinogenic amino acids in experimental probiotic suspensions (EPS) was studied by capillary electrophoresis. The scientific and economic experiment was carried out according to the method of A.I. Ovsyanikov, 1976.Results. In nutrient media based on oats (O, OP), the number of CFU of probiotic microorganisms has a certain variability. The increase in the abundance of B. subtilis CFU continued up to 6 days, in the OP sample it reached 5.8·107 CFU/cm, after what it decreased until 8th day down to 15.5·106 CFU/cm3. At the same time, the synthesis of amino acids is higher compared to control (germinated grain): lysine — in the range of 7.85–10.53 g/l, methionine — 2.03–2.35 g/l, leucine + isoleucine — in the range 5.79– 9.7 g/l. Indicators of protein metabolism are within the physiological norm in piglets of experimental groups. In piglets that received an experimental probiotic suspension, a more pronounced antagonistic effect, during the formation of microbiocenosis, was manifested to conditionally pathogenic bacteriaif they were given B. subtilis, obtained on a medium based on sprouted oats.

Proteome reallocation enables the selective de novo biosynthesis of non-linear, branched-chain acetate esters

The one-carbon recursive ketoacid elongation pathway is responsible for making various branched-chain amino acids, aldehydes, alcohols, ketoacids, and acetate esters in living cells. Controlling selective microbial biosynthesis of these target molecules at high efficiency is challenging due to enzyme promiscuity, regulation, and metabolic burden. In this study, we present a systematic modular design approach to control proteome reallocation for selective microbial biosynthesis of branched-chain acetate esters. Through pathway modularization, we partitioned the branched-chain ester pathways into four submodules including ketoisovalerate submodule for converting pyruvate to ketoisovalerate, ketoacid elongation submodule for producing longer carbon-chain ketoacids, ketoacid decarboxylase submodule for converting ketoacids to alcohols, and alcohol acyltransferase submodule for producing branched-chain acetate esters by condensing alcohols and acetyl-CoA. By systematic manipulation of pathway gene replication and transcription, enzyme specificity of the first committed steps of these submodules, and downstream competing pathways, we demonstrated selective microbial production of isoamyl acetate over isobutyl acetate. We found that the optimized isoamyl acetate pathway globally redistributed the amino acid fractions in the proteomes and required up to 23–31% proteome reallocation at the expense of other cellular resources, such as those required to generate precursor metabolites and energy for growth and amino acid biosynthesis. From glucose fed-batch fermentation, the engineered strains produced isoamyl acetate up to a titer of 8.8 g/L (>0.25 g/L toxicity limit), a yield of 0.22 g/g (61% of maximal theoretical value), and 86% selectivity, achieving the highest titers, yields and selectivity of isoamyl acetate reported to date.

Serum autoantibodyome reveals that healthy individuals share common autoantibodies

SUMMARYAutoantibodies are a hallmark of both autoimmune disease and cancer, but they also occur in healthy individuals. Here, we perform a meta-analysis of nine datasets and focus on the common autoantibodies shared by healthy individuals. We report 77 common autoantibodies based on the protein microarray data obtained from probing 182 healthy individual sera on 7,653 human proteins and an additional 90 healthy individual sera on 1,666 human proteins. There is no gender bias; however, the number of autoantibodies increase with age, plateauing around adolescence. We use a bioinformatics pipeline to determine possible molecular-mimicry peptides that can contribute to the elicitation of these common autoantibodies. There is enrichment of intrinsic properties of proteins like hydrophilicity, basicity, aromaticity, and flexibility for common autoantigens. Subcellular localization and tissue-expression analysis reveal that several common autoantigens are sequestered from the circulating autoantibodies.

Optimization of Protein Extraction from Tuna Cooking Liquid and Its Property Analysis

In order to provide scientific basis for the comprehensive utilization of high nitrogen waste water from tuna processing industry. Besides, it can provide theoretical guidance for pollution reduction in the industry. On the basis of single factor experiment, the effects of liquid-to-material ratio, temperature, time, pH, and solid content on the ethanol extraction of tuna cooking liquid protein were studied by response surface test. Further, the structure of the extracted protein was characterized by Ultraviolet Scanning, Infrared Spectroscopy, Aamino Acid Analyzer and Circular Dichroism. The results showed that the optimal process conditions were temperature 36 ℃, time 2 h, liquid-to-material ratio 2.4, and the maximum protein extraction rate was 76.83%. The protein extracted by this method had the maximum absorption peak at about 218 nm, but no obvious absorption peak at 280 nm. The amino acid composition showed that the mass fraction of amino acids was 18.79%, and the content of hydroxyproline was 10.21%. The infrared spectrum had the characteristic absorption peak of gelatin. The above results indicate that the protein extracted from the cooking liquid by this process is gelatin.

Raman Fingerprints of Rice Nutritional Quality: A Comparison between Japanese Koshihikari and Internationally Renowned Cultivars.

Raman spectroscopy was applied to characterize at the molecular scale the nutritional quality of the Japanese Koshihikari rice cultivar in comparison with other renowned rice cultivars including Carnaroli from Italy, Calrose from the USA, Jasmine rice from Thailand, and Basmati from both India and Pakistan. For comparison, two glutinous (mochigome) cultivars were also investigated. Calibrated and validated Raman analytical algorithms allowed quantitative determinations of: (i) amylopectin and amylose concentrations, (ii) fractions of aromatic amino acids, and (iii) protein content and secondary structure. The Raman assessments non-destructively linked the molecular composition of grains to key nutritional parameters and revealed a complex intertwine of chemical properties. The Koshihikari cultivar was rich in proteins (but with low statistical relevance as compared to other investigated cultivars) and aromatic amino acids. However, it also induced a clearly higher glycemic impact as compared to long-grain cultivars from Asian countries. Complementary to genomics and wet-chemistry analyses, Raman spectroscopy makes non-destructively available factual and data-driven information on rice nutritional characteristics, thus providing customers, dietitian nutritionists, and producers with a solid science-consolidated platform.

Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids

Proteins of halophilic organisms, which accumulate molar concentrations of KCl in their cytoplasm, have a much higher content in acidic amino acids than proteins of mesophilic organisms. It has been proposed that this excess is necessary to maintain proteins hydrated in an environment with low water activity, either via direct interactions between water and the carboxylate groups of acidic amino acids or via cooperative interactions between acidic amino acids and hydrated cations. Our simulation study of five halophilic proteins and five mesophilic counterparts does not support either possibility. The simulations use the AMBER ff14SB force field with newly optimized Lennard-Jones parameters for the interactions between carboxylate groups and potassium ions. We find that proteins with a larger fraction of acidic amino acids indeed have higher hydration levels, as measured by the concentration of water in their hydration shell and the number of water/protein hydrogen bonds. However, the hydration level of each protein is identical at low (bKCl = 0.15 mol/kg) and high (bKCl = 2 mol/kg) KCl concentrations; excess acidic amino acids are clearly not necessary to maintain proteins hydrated at high salt concentration. It has also been proposed that cooperative interactions between acidic amino acids in halophilic proteins and hydrated cations stabilize the folded protein structure and would lead to slower dynamics of the solvation shell. We find that the translational dynamics of the solvation shell is barely distinguishable between halophilic and mesophilic proteins; if such a cooperative effect exists, it does not have that entropic signature.

لا يوجد عنوان بالعربي في ملف الطلب على النظام

1,2-Indanedione (IND) is a chemical method for the detection of latent fingermarks on dry, porous surfaces such as paper, cardboard etc. It is an amino acid sensitive fluorescent reagent for developing latent fingermarks. The method is based on interaction of IND with amino acid fraction of latent fingermarks. The method develops clear, stable, pink (also known as Joullie pink) colored fingerprints which are fluorescent in nature. It is an efficient and non-destructive procedure for developing latent fingermarks on wide range of surfaces of forensic importance. Standardized testing of IND formulation is suggested to improve the eficiency of this reagent to develop latent fingermarks on wide range of surfaces of forensic importance.

Predicted Succinated Dehydrogenase Subunit Variant Pathogenicity: Why Are SDHB Variants “Bad”?

Variants in the 4 genes encoding subunits A-D of succinate dehydrogenase (SDH) are associated with paraganglioma and pheochromocytoma. Intuitively, loss-of-function variants affecting any of the subunits should equally diminish SDH function leading to succinate accumulation and tumorigenesis after loss of heterozygosity. However, variants in SDHB are associated with a higher prevalence of metastatic disease and a more aggressive clinical course. Evaluation of the SDH protein structure shows the fraction of amino acids in contact with other subunits or essential prosthetic groups to be: 13% (SDHA), 40% (SDHB), 28% (SDHC), and 28% (SDHD). We therefore hypothesized that SDHB missense variants are more penetrant because a larger fraction alter sensitive interfaces with other SDH subunits or essential molecular features (e.g. the three SDHB iron-sulfur clusters). We also wondered if truncating variants are more common for SDHB than other subunits. To test these hypotheses, we combined three databases (Genome Aggregation Database, ClinVar-NCBI-NIH, and Leiden Open Variant Database) and our institution’s data to create a pool of all known SDH variants. We categorized variants as truncating or missense and evaluated missense variants in the context of the SDH protein structure, scoring each variant in relation to important structures/interfaces and the severity of the amino acid change. This provided an ad hoc impact score for each variant, where a higher score predicts a more deleterious effect. We compared these scores to those obtained using the “Sorting Intolerant from Tolerant” (SIFT) tool that predicts impacts of amino acid changes based on evolutionary sequence conservation. SIFT scores of 0 to 0.05 predict deleterious effects. Both mean impact and SIFT scores could be weighted for the prevalence of each variant in the population. Our database included 2333 total SDH variants: SDHA (838, 36%), SDHB (703, 30%), SDHC (381, 16%), and SDHD (412, 18%). The fractions of truncating variants were 38%, 50%, 51%, and 53% for A-D subunits, respectively. When weighted for prevalence, these fractions were 0.39%, 6.8%, 8.2%, and 0.2%. The number of truncating variants per coding region length and the distribution of locations were similar between subunits. Ad hoc impact scores for A-D subunits were 3.08, 14.9, 9.93, and 11.0, respectively and, when weighted for prevalence, were 0.28, 3.25, 6.32, and 1.15. Mean SIFT scores for subunits A-D were: 0.185, 0.162, 0.238, and 0.410 respectively, and, when weighted for prevalence, were 0.58, 0.70, 0.22, and 0.018. Our results do not support the hypothesis SDHB variants predict a worse clinical outcome because average SDHB variants are, by chance, more biochemically severe. This suggests that SDHB loss may uniquely impact SDH biochemical function.

Effect of Hay Soaking Duration on Metabolizable Energy, Total and Prececal Digestible Crude Protein and Amino Acids, Non-Starch Carbohydrates, Macronutrients and Trace Elements

Soaking hay before feeding has been documented to reduce airborn respirable particles and water-soluble carbohydrate (WSC) content which may have positive benefits for horses suffering from Equine Asthma (EA) or Equine Metabolic Syndrome (EMS). Prolonged soaking also leaches minerals, but to-date no measurement of the loss of small intestine digestible crude protein has been documented. One aim of this study was to investigate various soaking durations on nutrient contents of hay, WSC, macronutrients, and trace elements levels. Another objective was to determine the prececal digestible crude protein (pcd CP) and amino acid (pcd AA) fraction contents and prececal digestibility (pcD). Four different batches of meadow hay were soaked in water (20° C during preparation) for 0 minutes, 15 minutes, 30 minutes, 60 minutes, and 12 hours and drained for 20 minutes. A 15 minutes soaking duration significantly reduced the levels of nearly all investigated nutrients (e.g. for fructans, and WSC, macronutrients and trace elements). However, the crude fiber, acid detergent fiber (ADF), and acid detergent lignin content increased. Metabolizable energy (ME) contents decreased by 5−15 %, pcd CP and pcd AA fell by 35 %, and the pcD declined by up to 49 %. In contrast, the pcD was 56 % before soaking. Longer soaking durations did not enhance the wash-out effect. Horse owners should be aware that soaking hay, regardless of reason, may negatively alter the nutritional value. The wide range of wash-out effects may pose risks in calculating the correct dry matter portion to prevent weight loss and maintain ME, pcd CP and pcd AA requirements, especially for horses with EMS and EA.

A new approach to recycling cephalosporin fermentation residue into plant biostimulants

Cephalosporin fermentation residue (CFR), a byproduct of the pharmaceutical industry, mainly contains the mycelial biomass and unutilized culture medium, which can be reused as a high-quality protein source. This study first reports the recycling CFR into plant biostimulants using partial acid hydrolysis. Temperature, reaction time and ratio of hydrochloric acid/dry matter (H/S) were optimized for yielding both free amino acid and low molecular weight fraction based on response surface methodology. The crude protein concentration of CFR is 55%, with glutamic acid being the dominant amino acid (12.5%). Two favorable hydrolysis conditions were obtained: (1) 140 °C, 10.7 h, 17 H/S for maximizing the amino acid yield of 45.5 g/100 g CFR dw and (2) 100 °C, 10.7 h, 19 H/S for maximizing the low molecular weight fraction of 28.2%. The CFR-derived biostimulants obtained from two optimum conditions possessed two biostimulant modes of action: plant growth promotors/inhibitors and stress alleviators. However, they showed the differences in aminograms and profiles of low molecular weight compounds. Neither residual cephalosporin C nor its byproduct was detected in the CFR-derived biostimulants, suggesting that partial acid hydrolysis appears capable of recycling CFR into plant biostimulant safely.