This study explores the electrochemical properties of the carbonaceous Allende CV3 meteorite, focusing on its potential as a Fe-based catalyst derived from Mackinawite iron sulfide for electrocatalytic reactions facilitating nitrogen (N2) fixation into ammonia. Through comprehensive analysis, we not only monitored the evolution of key compounds such as CN-, sulfur/H2S, H2 and carbonyl compounds, but also identified potential reagent carriers, indicating significant implications for the Strecker synthesis of amino acids in space environments. Initial examination revealed the presence of polypeptides, notably sequences including trimer Gly3, pentamer Gly3-Ala2, and hexamer Gly4-(HO-Gly)2. These discoveries greatly enhance our understanding of astrobiological chemistry, offering valuable insights into prebiotic processes and the potential presence of life-building blocks throughout the universe.

The abundance of potentially habitable hypersaline environments in our solar system compels us to understand the impacts of high-salt matrices and brine dynamics on biosignature detection efforts. We identified and quantified organic compounds in brines from South Bay Salt Works (SBSW), where evapoconcentration of ocean water enables exploration of the impact of NaCl- and MgCl2-dominated brines on the detection of potential biosignature molecules. In SBSW, organic biosignature abundance and distribution are likely influenced by evapoconcentration, osmolyte accumulation, and preservation effects. Bioluminescence assays show that adenosine triphosphate (ATP) concentrations are higher in NaCl-rich, low water activity (aw) samples (<0.85) from SBSW. This is consistent with the accumulation and preservation of ATP at low aw as described in past laboratory studies. The water-soluble small organic molecule inventory was determined by using microchip capillary electrophoresis paired with high-resolution mass spectrometry (µCE-HRMS). We analyzed the relative distribution of proteinogenic amino acids with a recently developed quantitative method using CE-separation and laser-induced fluorescence (LIF) detection of amino acids in hypersaline brines. Salinity trends for dissolved free amino acids were consistent with amino acid residue abundance determined from the proteome of the microbial community predicted from metagenomic data. This highlights a tangible connection up and down the \"-omics\" ladder across changing geochemical conditions. The detection of water-soluble organic compounds, specifically proteinogenic amino acids at high abundance (>7 mM) in concentrated brines, demonstrates that potential organic biomarkers accumulate at hypersaline sites and suggests the possibility of long-term preservation. The detection of such molecules in high abundance when using diverse analytical tools appropriate for spacecraft suggests that life detection within hypersaline environments, such as evaporates on Mars and the surface or subsurface brines of ocean world Europa, is plausible and argues such environments should be a high priority for future exploration. Key Words: Salts-Analytical chemistry-Amino acids-Biosignatures-Capillary electrophoresis-Preservation. Astrobiology 24, 795-812.

BACKGROUND: Maple syrup urine disease (MSUD) is caused by the deficiency of branched-chain keto acid dehydrogenase (BCKAD) and, it is well described that BCKAD contributed by an allograft following liver transplantation (LT) phenotypically normalizes this inborn error of metabolism (IEM). There is, however, a paucity of data especially with regards to the neurodevelopmental aspects and catch-up growth profiles after LT in a resource-challenged setting. We present our series of children under 6 years of age who underwent LT for MSUD particularly focusing on their amino acid homeostasis, neurodevelopmental and somatic growth profiles.
METHODS: Of 580 consecutive pediatric LT (PLT) performed between January 2011 and December 2022, all children who underwent LT for MSUD were included for analysis. Data accrued included peri-LT details, pre- and post-LT metabolic profile, neurodevelopmental assessment, somatic growth evaluation, and long-term outcomes.
RESULTS: Six children underwent LT for MSUD with a median age and weight at LT of 20.5 (IQR: 8-60) months and 10.1 (IQR: 6.7-15.8) kg, respectively. One explanted liver was used as a domino graft for Arginase deficiency. Median follow-up period was 52.5 (IQR: 27-94) months. None had vascular or biliary complications. Following LT, all children were started on an unrestricted protein diet and had normalization of BCAA levels. Post-LT height and weight improved by 1 SD but did not achieve the normal profile. None of the children had neuro-deterioration and have achieved new milestones.
CONCLUSIONS: This is the first-report presenting the growth aspects, amino acid and neurodevelopmental profiles of children who underwent LT for MSUD within the socio-economic-cultural idiosyncrasies and constraints prevalent in our part of the world.

OBJECTIVE: To analyze the nutrient composition and nutritional value evaluation of 5 potatoes in Anqing City.
METHODS: According to the requirements of the Technical Manual for Food Composition Monitoring Projects, 5 types of potato samples were collected from Anqing City, Anhui Province. National standard detection method were used to determine the nutritional components such as water, ash, protein, fat, dietary fiber, sugar, minerals, vitamins, and amino acids in the samples. The index of nutritional quality(INQ) method was used to evaluate proteins, vitamins, and minerals, and the amino acid scoring standard mode(FAO/WHO mode) was used to evaluate the nutritional value of amino acids.
RESULTS: Among the 5 types of potatoes, purple potato had the highest protein(2.3 g/100 g) and dietary fiber content(3.6 g/100 g). Sweet potato(red) had the highest carotene content(4003 μg/100 g), sweet potato(white) had the highest content of vitamin C(15.4 mg/100 g). Sugar in potatoes mainly existed in three forms: fructose, glucose, and sucrose; Purple potatoes had the highest levels of calcium(47 mg/100 g) and phosphorus(74 mg/100 g), respectively. Potatoes(white) had the highest content of potassium(401 mg/100 g), while sweet potatoes(red) had the highest content of magnesium(31 mg/100 g). Sodium(104.0 mg/100 g), iron(0.9 mg/100 g), copper(0.17 mg/100 g), and manganese(0.40 mg/100 g) had the highest content in sweet potatoes(white). The Na/K ratio range of the 5 potato varieties was 0.003-0.456, and the INQ of phosphorus, potassium, magnesium, copper, and manganese were greater than 1. The detection result of 5 potatoes all contain 18 amino acids, and aspartic acid was the highest. The amino acid score(AAS) was 0.29-1.35, and the ratio coefficient(RC) was 0.47-1.69.
CONCLUSIONS: The 5 types of potatoes are rich in dietary fiber, vitamin C and minerals, and belong to the high potassium and low sodium type of food. Potatoes can meet the daily needs of the human body for phosphorus, potassium, magnesium copper, and manganese elements. Lysine is rich in content and can be used as a nutritional supplement for grains. The AAS score and RC are close to 1, and the AAS evaluation mode is closer to the human amino acid composition mode, which can meet the daily needs of the human body for this essential amino acid.

The protein value of any food item is determined by the quantity and ileal digestibility of indispensable amino acids in that food. To determine the ileal digestibility of amino acids, an animal model needs to be used, and the pig is the preferred model because values for ileal digestibility obtained in pigs are representative of values obtained in humans. In addition, pigs are omnivorous animals like humans, they are meal eaters, they consume most diets that humans consume, they are easy to work with, and they can be used for repeated determinations of digestibility in many foods. It is, therefore, possible to use pigs to establish a database with digestibility values for human foods and by correcting digestibility values obtained in pigs for the basal endogenous losses of amino acids, it is possible to calculate true ileal digestibility values that are additive in mixed meals. As a consequence, the protein quality of a meal consisting of several food items can be calculated based on digestibility values obtained in pigs. Future work needs to focus on expanding existing databases for amino acid digestibility in foods to include more food items, which will make it possible to estimate the amino acid value of more mixed meals. It is also necessary that the amino acid values in mixed meals be related to requirements for digestible indispensable amino acids in the individuals consuming the meals. The current contribution describes the basic steps in determining amino acid digestibility in human foods using the pig as a model and also outlines future steps needed to further improve amino acid nutrition in humans.

This research aims to assess the effect of amino acids as lipid antioxidants in reducing the formation of volatile aldehydes in frying oil. Methionine, histidine, and glycine at concentrations of 2.5, 5, and 10 mM were added to high oleic sunflower oil (HOSO) to investigate their effects on the distribution and formation of saturated, monounsaturated, and polyunsaturated volatile aldehydes. The results showed that the proportion of saturated volatile aldehydes was greater than that of unsaturated ones; Methionine exhibited the best inhibitory effect, after 12 h of frying, 10 mM methionine reduced the content of saturated volatile aldehydes by 24.21 %, monounsaturated by 52.4 %, and polyunsaturated by 54.73 % compared to the control. Methionine\'s sulfur-containing side chain was also proven to have strong antioxidant activity. Combined with the results of this study, this can also provide insights for using amino acids as lipid antioxidants.

To investigate the quality of different ozone-oxidized surimi gels and their in vitro digestion and absorption characteristics, surimi rinsed with different concentrations of ozonated water (0, 8, 26 mg/L) were prepared. Then, the degree of oxidation and gel structure of surimi were determined, the in vitro digestion and absorption of the gels were simulated, and the digestion and absorption products were analyzed by LC-MS/MS. The results showed that the quality of surimi gels was improved after proper ozone oxidation. After ozone water rinsing, the dry matter digestibility, peptide, and amino acid content increased, and the changes of all three were in line with the Logistic kinetic model (R2 = 0.95-0.99). Caco-2 cell absorption experiments showed that the absorption rate of peptides and amino acids decreased after ozone water rinsing. In summary, ozone oxidation can promote the digestion of surimi gels, but it also reduces the absorption of peptides and amino acids by Caco-2 cells. This study provides a reference for the application of ozone in the food field.

The structure of helical polymers is dictated by the molecular chirality of their monomer units. Particularly, macromolecular helices with monomer sequence control have the potential to generate chiral topologies. In α-helical folded peptides, the sequential repetition of amino acids generates a chiral layer defined by the amino acid side chains projected outside the amide backbone. Despite being closely related to peptides\' structural and functional properties, to the best of our knowledge, a general exo-helical symmetry model has not been yet described for the α-helix. Here, we perform the theoretical, computational, and spectroscopic elucidation of the α-helix principal exo-helical topologies. Non-canonical labeled amino acids are employed to spectroscopically characterize the different exo-helical topologies in solution, which precisely match the theorical prediction. Backbone-to-chromophore distance also shows the expected impact in the exo-helices\' geometry and spectroscopic fingerprint. Theoretical prediction and spectroscopic validation of this exo-helical topological model provides robust experimental evidence of the chiral potential on the surface of helical peptides and outlines an entirely new structural scenario for the α-helix.

Chemosensory cells across the body of Drosophila melanogaster evaluate the environment to prioritize certain behaviors. Previous mapping of gustatory receptor neurons (GRNs) on the fly labellum identified a set of neurons in L-type sensilla that express Ionotropic Receptor 94e (IR94e), but the impact of IR94e GRNs on behavior remains unclear. We used optogenetics and chemogenetics to activate IR94e neurons and found that they drive mild feeding suppression but enhance egg laying. In vivo calcium imaging revealed that IR94e GRNs respond strongly to certain amino acids, including glutamate, and that IR94e plus co-receptors IR25a and IR76b are required for amino acid detection. Furthermore, IR94e mutants show behavioral changes to solutions containing amino acids, including increased consumption and decreased egg laying. Overall, our results suggest that IR94e GRNs on the fly labellum discourage feeding and encourage egg laying as part of an important behavioral switch in response to certain chemical cues.

Pacific spiny dogfish, Squalus suckleyi, move to shallow coastal waters during critical reproductive life stages and are thus at risk of encountering hypoxic events which occur more frequently in these areas. For effective conservation management, we need to fully understand the consequences of hypoxia on marine key species such as elasmobranchs. Because of their benthic life style, we hypothesized that S. suckleyi are hypoxia tolerant and able to efficiently regulate oxygen consumption, and that anaerobic metabolism is supported by a broad range of metabolites including ketones, fatty acids and amino acids. Therefore, we studied oxygen consumption rates, ventilation frequency and amplitude, blood gasses, acid-base regulation, and changes in plasma and tissue metabolites during progressive hypoxia. Our results show that critical oxygen levels (P crit) where oxyregulation is lost were indeed low (18.1% air saturation or 28.5 Torr at 13°C). However, many dogfish behaved as oxyconformers rather than oxyregulators. Arterial blood PO2 levels mostly decreased linearly with decreasing environmental PO2. Blood gases and acid-base status were dependent on open versus closed respirometry but in both set-ups ventilation frequency increased. Hypoxia below Pcrit resulted in an up-regulation of anaerobic glycolysis, as evidenced by increased lactate levels in all tissues except brain. Elasmobranchs typically rely on ketone bodies as oxidative substrates, and decreased concentrations of acetoacetate and β-hydroxybutyrate were observed in white muscle of hypoxic and/or recovering fish. Furthermore, reductions in isoleucine, glutamate, glutamine and other amino acids were observed. After 6 hours of normoxic recovery, changes persisted and only lactate returned to normal in most tissues. This emphasizes the importance of using suitable bioindicators adjusted to preferred metabolic pathways of the target species in conservation physiology. We conclude that Pacific spiny dogfish can tolerate severe transient hypoxic events, but recovery is slow and negative impacts can be expected when hypoxia persists.