Free Amino Acid Content Research Articles

Structural and sensory characteristics of ultrasonic assisted wet-heating Maillard reaction products of Giant salamander protein hydrolysates.

Chinese giant salamander protein hydrolysates (CGSPH) are beneficial to human health as a result of their high content of amino acids and peptides. However, the formation of bitter peptides in protein hydrolysates (PHs) would hinder their application in food industry. The ultrasound assisted wet-heating Maillard reaction (MR) is an effective way to improve the flavor of PHs. Thus, the effect of ultrasonic assisted wet-heating MR on the structure and flavor of CGSPH was investigated in the present study. The results indicated that the ultrasound assisted wet-heating MR products (MRPs) exhibited a higher degree of graft and more significant changes in the secondary and tertiary structures of CGSPH compared to traditional wet-heating MRPs. Moreover, ultrasound assisted wet-heating MR could significantly increase the content of small molecule peptides and reduce the content of free amino acids of CGSPH, which resulted in more significant changes in flavor characteristics. The changed in flavor properties after MR (especially ultrasound assisted wet-heating MRPs) were mainly manifested by a significant reduction in bitterness, as well as a significant increase in the content of aromatic aldehyde ester compounds such as furan-2-carbaldehyde, butanal, benzaldehyde, furfural, etc. CONCLUSIONS: Ultrasound assisted wet-heating MR between CGSPH and xylose could be a promising way to improve the sensory characteristics of CGSPH. © 2024 Society of Chemical Industry.

Chloroplast-localized PvBASS2 regulates salt tolerance in the C4 plant seashore paspalum.

SODIUM SYMPORTER FAMILY PROTEIN 2 (BASS2) is localized within chloroplast membranes, facilitating the translocation of pyruvate and Na+ from the cytosol to the plastid, where pyruvate supports isopentenyl diphosphate (IPP) synthesis via the methylerythritol phosphate pathway in C3 plants. Nevertheless, the biological function of BASS2 in C4 plants has not been well defined. This study unveils a previously unidentified role of PvBASS2 in Na+ and pyruvate transport in seashore paspalum (Paspalum vaginatum), a halophytic C4 grass, indicating a specific cellular function within this plant species. Data showed that overexpression of PvBASS2 in seashore paspalum attenuated salt tolerance, whereas its RNAi lines exhibited enhanced salt resistance compared to wild-type plants, suggesting a negative regulatory role of PvBASS2 in seashore paspalum salt tolerance. The constitutive overexpression of PvBASS2 was also found to reduce salt tolerance in Arabidopsis. Further study revealed that PvBASS2 negatively regulates seashore paspalum salt tolerance, possibly due to elevated Na+/K+ ratio, disrupted chloroplast structure, and reduced photosynthetic efficiency following exposure to salinity. Importantly, our subsequent investigations revealed that modulation of PvBASS2 expression in seashore paspalum influenced carbon dioxide assimilation, intermediary metabolites of the tricarboxylic acid cycle, and enzymatic activities under salinity treatment, which in turn led to alterations in free amino acid concentrations. Thus, this study reveals a role for BASS2 in the C4 plant seashore paspalum and enhances our comprehension of salt stress responses in C4 plants.

Modulating Weak Protein-Protein Cross-Interactions by the Addition of Free Amino Acids at Millimolar Concentrations.

In this paper, we quantify weak protein-protein interactions in solution using cross-interaction chromatography (CIC) and surface plasmon resonance (SPR) and demonstrate that they can be modulated by the addition of millimolar concentrations of free amino acids. With CIC, we determined the second osmotic virial cross-interaction coefficient (B23) as a proxy for the interaction strength between two different proteins. We perform SPR experiments to establish the binding affinity between the same proteins. With CIC, we show that the amino acids proline, glutamine, and arginine render the protein cross-interactions more repulsive or equivalently less attractive. Specifically, we measured B23 between lysozyme (Lys) and bovine serum albumin (BSA) and between Lys and protein isolates (whey and canola). We find that B23 increases when amino acids are added to the solution even at millimolar concentrations, corresponding to protein/ligand stoichiometric ratios as low as 1:1. With SPR, we show that the binding affinity between proteins can change by 1 order of magnitude when 10 mM glutamine is added. In the case of Lys and one whey protein isolate (WPI), it changes from the mM to the M range, thus by 3 orders of magnitude. Interestingly, this efficient modulation of the protein cross-interactions does not alter the protein's secondary structure. The capacity of amino acids to modulate protein cross-interactions at mM concentrations is remarkable and may have an impact across fields in particular for specific applications in the food or pharmaceutical industries.

Deciphering the alleviation potential of nitric oxide, for low temperature and chromium stress via maintaining photosynthetic capacity, antioxidant defence, and redox homeostasis in rice (Oryza sativa)

Sodium nitroprusside (SNP) is a potent nitric oxide (NO) donor that enhances plant tolerance to various abiotic stresses. This research aims to assess the effect of SNP application on rice seedlings subjected to individual and combined exposure to two abiotic stresses viz., low-temperature (LT) and chromium (Cr). Exposure to LT, Cr, and LT+Cr caused severe oxidative damage by stimulating greater production and accumulation of reactive oxygen species (ROS) leading to lipid peroxidation and cell membrane instability. The combined LT+CR stress more intensly increased the cellular oxidative stress and excessive Cr uptake that in turn deteriorated the chlorophyll pigments and photosynthesis, as well as effected the level of tetrapyrrole biosynthesis in rice plants. The reduction in rice seedling growth was more obvious under LT+Cr treatment than their individual effects. The exogenous application of SNP diminished the toxic impact of LT and Cr stress. This was attributed to the positive role of SNP in regulating the endogenous NO levels, free amino acids (FAAs) contents, tetrapyrrole biosynthesis and antioxidants. Consequently, SNP-induced NO decreased photorespiration, ROS generation, lipid peroxidation, and electrolyte leakage. Moreover, exogenous SNP diminished the Cr uptake and accumulation by modulating the ionic homeostasis and strengthening the heavy metals detoxification mechanism, thus improving plant height, biomass and photosynthetic indexes. Essentially, SNP boosts plant tolerance to LT and Cr stress by regulating antioxidants, detoxification mechanism, and the plant's physio-biochemical. Hence, applying SNP is an effective method for boosting rice plant resilience and productivity in the face of escalating environmental stresses and pollutants.

Chicatana ant (Atta mexicana) as a potential source of biologically active substances

Atta mexicana (Smith, 1858) is a leaf-cutting ant from the neotropical forests and an important pest. The abdomens of the reproductive specimens are consumed as food and medicinal remedies in the southwest of Mexico. Because their high-quality proteins remain unexplored, the protein profile and the free amino acid content were analyzed through a metabolomic approach. We identified 2247 proteins in the abdomen and edible part of the Chicatana ant and 2098 proteins in the whole insect, visualizing a core of 1186 proteins. Thus, we carried out a targeted metabolomic approach with a bioinformatic prediction that suggests the occurrence of antimicrobial tryptic peptides in the Atta mexicana proteome. These findings are the first description of the free amino acid and protein profiles of Atta mexicana.

Characteristics of Umami Taste of Soy Sauce Using Electronic Tongue, Amino Acid Analyzer, and MALDI-TOF MS.

The objective of this study was to investigate the umami characteristics of soy sauce using electronic tongue evaluation and amino acid composition and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. The soy sauce peptides were isolated from soy sauce using XAD-16 macroporous resin combined with ethanol solution. The results showed that the soy sauce peptide fraction eluted by 60% ethanol (SS-60%) exhibited a prominent umami taste, and the umami scores were highly positively correlated with the amino acid nitrogen contents of soy sauces. The umami scores of SS-60% were significantly positively correlated with the contents of free amino acids. Especially, Phe showed the highest positive correlation with the umami scores. In addition, five characteristic ion peaks with m/z at 499, 561, 643, 649, and 855 were identified in the peptide mass fingerprinting. Therefore, this study provides new insights into the umami characteristics for the taste evaluation and reality identification of soy sauce.

The salinity impact on changes in some metabolites and some vital subcellular organelles in white maize

BackgroundThe great need to propagate new crop genotypes that are well adapted to the changing environmental conditions is urgently needed to support the high demand of food of the growing world population. In this work five white maize inbred lines (P4, P8, P12, P15, and P17) were studied for their salinity tolerance when exposed to: 0, 1000, 2000, 3000, and 10000 mg/L NaCl. The equilibrium balance between reactive oxygen species ROS and the detoxification cascades points to the plant’s performance under stress. The free amino acid and soluble sugar contents (non-enzymatic antioxidants) in addition to the superoxide dismutase & Phenylalanine ammonia-lyase SOD& PAL (enzymatic antioxidants) and some phenolic compounds contents were evaluated against hydrogen peroxide H2O2 as ROS product to classify plants to stress -tolerance or sensitive. Transmission electronic microscope (TEM) investigation is also, used to study the impact of the stress on the plant cells’ compartments after the direct treatment with saline water for 3 h as moderate soil holding time capacity to irrigation water.ResultsMaize line P8 followed by line P17 were the highest to cope with the irrigation of saline water in different ranges of concentrations of salt, accumulate the soluble sugars, free amino acids and antioxidants over control and other maize lines. These results are supported by the root ultrastructure observation with transmission electronic microscope.ConclusionMaize line P8 followed by the P17 line are highly recommended to be crossed and planted in the newly reclaimed lands irrigated with salty water.Graphical

Physiological, genetical changes and cdc2 gene expression for osmotic stressed Vicia faba reveal the alleviation effect of gamma radiation and putrescine

Climate change caused increasing in soil salinity worldwide. Therefore, it is critical to enhance the capability of plant to tolerate salinity stress. For this goal, putrescine and irradiation by gamma radiation were used to improve the salt tolerance of Vicia faba (the most important human crop). The results indicated depression in mitotic division and all growth parameters associated with the induction of micronucleus (MN) when salinity increased to 100mM, while there was increase in mitotic aberrations. NaCl decreased total soluble sugar, while total N%, total free amino acid, proline and protein contents showed slight increase with increasing salinity stress. Putrescine and gamma radiation mitigated the effect of salinity on cell division and growth parameters. Salt stress decreased the expression of gene encoding cyclin-dependent kinase 2 (cdc2). Both putrescine and gamma radiation increased cdc2 expression. The genetic diversity has been detected among control and treated V. faba using ISSR and SCoT markers. Ten primers had successfully generated 129 reproducible polymorphic amplicons that were suitable for studying the genetic diversity between studied genotypes. ISSR markers provided more discriminating data and were more informative than SCoT markers. Besides, cluster analysis using UPGMA and PAC successfully explained the genetic diversity within studied genotypes. These findings emphasize the efficiency of putrescine and gamma radiation for alleviating the negative impact of salt stress. Moreover, prove the importance of assessing mitotic activity, chromosomes behavior, physiological parameters, the expression level of cdc2 and molecular diversity in V. faba under stress to improve the salt tolerance of it.

The promotion and inhibition of proteolysis in silages during ensiling of citrus waste

Although waste generated from the production of citrus fruit juice is a suitable raw material for ensiling, excessive proteolysis greatly reduces the quality of silages and economic benefits. The driving force and factors influencing proteolysis during ensiling remain poorly understood. In this study, the degree of silage proteolysis was systematically evaluated through the analysis of silage composition, proteolysis promotion and inhibition under various ensiling factors were quantified, and the causes of proteolysis were explored through changes of microbiome. A reduction in soluble protein (SP) and in-solution protein (ISP) contents coupled with an increase in NH3-N were found after ensiling. A decrease in free amino acid content was evident in upper and middle sections, whereas there was an increase in the bottom section. The strongest proteolysis of silages was observed in the middle section. The main factor accelerating hydrolysis of protein into amino acid (the first stage of proteolysis) was acid protease activity (APA). The hydrolysis of amino acid into NH3-N (the second stage of proteolysis) was principally inhibited by lactic acids, acetic acids, pH, and soluble carbon, and accelerated by APA, moisture and total carbon. Acid protease was probably constituted mainly microbial protease, able to tolerate a pH range of 3.44–3.77. Bacterial coupled colony (B-CC), Trichocomaoute, and Trichocomaceae-1 presumably promoted the production and activity of acid protease. As inferred, the first stage of proteolysis was promoted by B-CC and fungal coupled colony (F-CC), and inhibited by Trichocomaoute. While the second stage of proteolysis was likely promoted by P. kudriavzevii and F-CC, and inhibited by B-CC and Trichocomaoute. Thus, the use of homofermentative lactic acid bacteria in raw materials is recommended to reduce the degree of proteolysis, particularly in the middle section of the silo.

Production of microcapsules by Maillard reaction of soy protein isolate and sodium carboxymethyl cellulose for protection of bifidobacterium lactis

Soy protein isolate (SPI) and sodium carboxymethyl cellulose (CMC-Na) were combined in varying proportions and subjected to the Maillard reaction through spray drying and dry-heat methods. The effects of different mixing ratios and reaction times on the physicochemical properties of the reaction products were investigated, with a focus on their application as wall material for bifidobacterium lactis BB-12. The solubility of the system was significantly enhanced by the Maillard reaction, reaching its maximum at an SPI:CMC-Na ratio of 1:2. At this proportion, after a 6-hour dry-heat Maillard reaction, there was a significant increase in ultraviolet absorption and browning degree of the product, while the free amino acid content decreased significantly. Fluorescence spectroscopy revealed that the conformation around tryptophan residues remained in its natural form, whereas circular dichroism spectroscopy showed a decrease in α-helix and Random coil structure content upon addition of CMC-Na, accompanied by an increase in β-sheet and β-turn content. This stretching effect on protein molecules facilitated functional property expression. Compared to unencapsulated probiotics BB-12 microcapsules prepared using secondary spray drying with a wall-core volume ratio of 6:1 exhibited higher encapsulation efficiency along with good storage stability, tolerance to gastrointestinal conditions, and heat stability. These findings have practical implications for preserving bioactive substances in the food industry.

Valorization of Saithe (Pollachius virens) Residuals into Protein Hydrolysates-Silaging as Preservation Technology.

Silaging can be used as preservation technology to valorize currently discarded raw material into protein hydrolysate on board deep-sea vessels. The aim of this study was to investigate the effect of sorting and raw material freshness on the quality and yield of protein hydrolysates obtained through silaging of saithe (Pollachius virens) viscera. Additionally, the effect of using acid-containing antioxidants was tested. Out sorting of the liver prior to silaging resulted in slightly higher hydrolysate yields. The hydrolysates with the highest protein contents were obtained from silages made from fresh raw materials (day 0), and the content decreased significantly after longer storage of the raw material (2-3 days at 4 °C). Storage of the raw material for 1 day did not affect the quality. However, a significantly higher degree of hydrolysis (DH), content of free amino acids (FAA), and total volatile basic nitrogen (TVB-N) were obtained when raw materials were stored for 3 days. The FAA composition was influenced by the raw material's freshness, with increases in free glutamic acid and lysine and a decrease in free glutamine after longer storage. None of the studied parameters were significantly affected by out sorting of liver or the addition of antioxidants. Overall, the results indicate that the whole fraction of the viscera can be utilized without reducing the quality of the hydrolysate and that the raw material should be stored for a maximum of 1 day prior to preservation to optimize the quality.

Fermentation with Lactic Acid Bacteria for Bean Flour Improvement: Experimental Study and Molecular Modeling as Complementary Tools.

Pulses are considered superfoods for the future world due to their properties, but they require processing to reduce antinutritional factors (ANFs) and increase bioactivity. In this study, bean flour (Phaseolus vulgaris L.) was fermented under different conditions (addition of Lactiplantibacillus plantarum CRL 2211 and/or Weissella paramesenteroides CRL 2182, temperature, time and dough yield) to improve its nutri-functional quality. Fermentation for 24 h at 37 °C with the mixed starter increased the lactic acid bacteria (LAB) population, acidity, polyphenol content (TPC) and ANF removal more than spontaneous fermentation. Statistical and rep-PCR analysis showed that fermentation was mainly conducted by Lp. plantarum CRL 2211. Metabolic modeling revealed potential cross-feeding between Lp. plantarum and W. paramesenteroides, while the molecular docking and dynamic simulation of LAB tannases and proteinases involved in ANF removal revealed their chemical affinity to gallocatechin and trypsin inhibitors. Fermentation was better than soaking, germination and cooking for enhancing bean flour properties: it increased the free amino acids content by 50% by releasing glutamine, glutamic acid, arginine, leucine and lysine and modified TPC by increasing gallic acid and decreasing caffeic, ferulic and vanillic acids and quercetin-3-glucoside. The combination of experimental and simulation data may help us to understand fermentation processes and to design products with desirable features.

The Increased aspartate levels in transgenic cotton (Gossypium hirsutum L.) lead to improved tolerance against whitefly (Bemisia tabaci, Gennadius).

The whitefly, a polyphagous insect pest feeding on nearly 1328 plant species, is a major threat to global cotton production and incurs up to 50% yield losses in cotton production in Pakistan. We investigated whether increased aspartate in phloem sap imparts whitefly toxicity and protects cotton plants from intense damage. The enzymatic step for aspartate production is carried through aspartate aminotransferase (AAT). In this study, we constitutively overexpressed the Oryza sativa cytoplasmic AAT (OsAAT2) under the CaMV35S promoter in Gossypium hirsutum cv. CIM-482. Real-time PCR analysis of the AAT transcripts revealed a 2.85- to 31.7-fold increase in mRNA levels between the different cotton lines. A substantial increase in the free-amino acid content of the major N-assimilation and transport amino acids (aspartate, glutamate, asparagine, and glutamine) was seen in the phloem sap of the transgenic cotton lines. The bioassay revealed that the two transgenic cotton lines with the highest free aspartate content in the phloem sap exhibited 97 and 94% mortality in the adult whitefly population and a 98 and 96% decline in subsequent nymph populations, respectively. There was also a significant change in the physiological behaviour of the transgenic cotton lines, with an increased net assimilation (A), gaseous exchange (Gs) and rate of transpiration (E). Improved morphological characteristics like plant height, total number of bolls and fiber yield were recorded in transgenic cotton lines. The AAT gene shows promise in mitigating whitefly infestations and enhancing the overall health and yield of cotton plants.

Comprehensive analysis of botanical origin and amino acid composition of bee pollen samples from various regions of Turkey

This study aimed to investigate the botanical diversity in bee pollen and amino acid composition of Turkish bee pollen samples collected from different regions. The monofloral bee pollen samples belonged to three different plant families: Asteraceae, Fabaceae, and Ranunculaceae. Additionally, Agean, Central Anatolian, Black Sea, and Marmara Regions have monofloral bee pollen samples with higher than 85% pollen frequency. The free amino acid (FAA) composition and content of the bee pollen samples were analyzed, with the essential amino acids comprising 13.13–18.28% of the total amino acid content. The Central Anatolian region displayed the highest ratio of essential amino acids, and the Aegean region exhibited a more diverse profile of FAA. Principal Component Analysis was performed to evaluate the variation in the data, with the eigenvalues of the two factors explaining 68.58% of the total variability. Moreover, cluster analysis revealed distinct dendrograms based on palynological characteristics and FAA composition.

Preparation and characterization of Maillard reaction products from enzymatic hydrolysate products of abalone viscera

The abalone viscera contain high levels of proteins, amino acids and other bioactive compounds that possess significant utilitarian value. In this study, abalone viscera were used as raw material and the enzymatic hydrolysates were hydrolyzed by biological enzymes. The flavor and taste of the enzymatic hydrolysates were improved by the Maillard reaction. The results showed the Maillard reaction products (MRPs) had a high antioxidant activity. The GC–MS with headspace solid phase microextraction results indicated aldehydes and ketones were the main volatile compounds, and the content of fishy and unpleasant odors in the MRPs decreased or even disappeared. E-tongue results showed the bitter and astringent flavors in the MRPs were significantly reduced. The content of free amino acids presenting bitter flavors was significantly reduced. In conclusion, the flavor of the enzymatic hydrolysates could be improved greatly after the Maillard reaction, and the MRPs had the potential to be used as flavorings.

EFFECT OF CRYO-STORAGE ON STORABILITY OF PAPAYA SEEDS

A fruit crop of significant economic importance, papayas are often propagated from seeds. Based on their freezing injury even at low moisture content, papaya seeds are classified as "intermediate seeds"; and rapid loss of viability in storage is assumed to be the primary cause of poor germination; thus, the development of appropriate technology is necessary to prolong the storability of papaya seeds. One such effective technology for prolonged seed storability is cryo-storage. The purpose of the current study was to investigate how cryostorage affects papaya seed storability. For this investigation, TNAU Papaya variety CO 8 seeds were utilised. Five distinct treatments were applied to the seeds, which were then kept for approximately six months at liquid nitrogen's vapour phase (-140°C). The biochemical parameters such as protein content, free amino acid, total carbohydrates, free sugars, total lipids, and dehydrogenase activity were measured on a monthly basis along with seed germination and seedling vigour in the cryopreserved papaya seeds. Results indicated that papaya seeds that had been vitrified (seeds with a 10% moisture content that had been soaked in loading solution for 20 minutes, then immersed in Plant Vitrification Solution 2 (PVS2) for another 20 minutes, packed in cryovials and kept in cryo-storage at -140°C) compared to papaya seeds that were packed in cloth bags and stored in ambient conditions had higher seed germination, dry matter production and vigour index at six months after storage. In comparison to fresh seeds, the results also showed that, after six months of cryo-storage, biochemical proximate, protein content, total carbohydrate content, total lipid content, and dehydrogenase activity were maintained in the aforementioned treatment with minimum reduction, while electrical conductivity, free amino acid content, and free sugar content gradually increased with the storage period at minimum rate. In crux, vitrified papaya seeds packaged in cryovials and kept in cryo-storage at -140°C preserved their quality for six months, meeting Indian Minimum Seed Certification Standards. This could be useful for storing papaya seeds for longer periods of time. Keywords: Papaya, vitrification, differential scanning calorimetry, liquid nitrogen, cryo-storage

Exploring the influence and mechanism of different frying methods on the flavor quality of low-salt sour meat

To obtain nutritious, healthy, and flavor-enriched sour meat products, the effects of different frying methods (microwave, air-frying, and traditional frying) on the flavor quality of low-salt sour meat were evaluated using metabolomics and other flavor analysis techniques. The pH value of the sour meat rose dramatically, while the TBARS value dropped significantly after frying. E-nose and E-tongue results showed that air-frying could reduce acidity and improve umami. The comprehensive analysis of all samples revealed the identification of 107 volatile flavor compounds, including 10 unique aroma compounds that were specifically detected in the AF group. Additionally, the air frying process notably increased the free amino acid and nucleotide concentrations in sour meat by 53.58% and 159.29%, respectively, while causing a significant reduction in both fatty acid and lactic acid content by 22.84% and 49.29%, respectively. All three frying methods altered the flavor of the samples, but air frying performed better in terms of flavor and texture.

Characterization of physicochemical properties, volatile compounds and microbial diversities of inoculated Dajiang on industrial scale

Dajiang has a long history of being an important condiment. Previous research on Dajiang has predominantly centered on laboratory-scale studies or extensive durations of natural fermentation, resulting in limited comprehension of the quality variations and microbial community succession in inoculation industrial-scale production. In this study, physicochemical attributes, volatile compounds and microbial communities of industrialized Dajiang were determined. During the fermentation process, notable increases in the content of free amino acids, total acids, volatile compounds and reddish-brown were observed. Aspergillus, Zygosaccharomyces, and Staphylococcus were identified as the dominant microorganisms. While Aspergillus showed a gradual decline in abundance, Zygosaccharomyces and Staphylococcus exhibited an increasing trend. Redundancy analysis revealed salinity as the primary driving force behind the changes in the microbial community during fermentation. Furthermore, Spearman's correlation analysis demonstrated significant positive associations between Zygosaccharomyces and Staphylococcus with the volatile compounds of Dajiang, suggesting their crucial role in shaping the unique flavor profile of Dajiang. This study provides a solid foundation for understanding the alterations in microbial community composition and physicochemical metabolites during industrial-scale inoculation fermentation of Dajiang.

Species-specific metabolome changes during salinity downshift in sub-Arctic populations of Mytilus edulis and M. trossulus

The blue mussels Mytilus edulis and Mytilus trossulus are ecologically and economically important species distributed widely across the Northern Hemisphere. Understanding their behavioral and physiological disparities is crucial for assessing their ecological success and aquacultural value. The recent finding of non-native M. trossulus in the White Sea raises concerns regarding its potential competition with native M. edulis and its prospective spread in light of climate change and surface water freshening. We investigated the responses of M. edulis and M. trossulus to salinity variations by examining shell closure thresholds and tissue levels of 35 metabolic intermediates in mussels acclimated to different salinities (25, 16, and 10). The salinity threshold for valve closure was similar in both studied species, but M. trossulus consistently opened at lower salinities (by 0.2–0.7 practical salinity units) compared to M. edulis. Salinity-induced changes in metabolite levels were similar between the two species. Taurine emerged as the dominant osmolyte, comprising over 50% of the total free amino acid pool, with aspartate and glycine contributing 15–30%. Concentrations of taurine, glycine, and total free amino acids declined with decreasing salinity. Taurine to glycine ratios were higher in M. edulis and increased in both species with declining salinity. Acclimation salinity significantly influenced urea cycle intermediates and methionine sulfoxide content, a cellular biomarker of amino acid oxidation. Species-specific differences were observed in purine metabolism, with higher levels of GMP and AMP found in M. edulis. Likewise, aromatic amino acids and histidine levels were higher in M. edulis compared to M. trossulus. However, no evidence suggests superior adaptation of M. trossulus metabolism to hypoosmotic stress compared to M. edulis. Further research is necessary to elucidate the functional implications of subtle metabolic differences between these Mytilus congeners and their ecological consequences in changing marine environments.

Gamma amino butyric acid (GABA) application modulated the morpho-physiological and yield traits of fragrant rice under well-watered and drought conditions

BackgroundChanging climate is causing erratic rainfall and prolonged drought periods, thus posing serious threats to crop productivity. Owing to severity of drought events, it is imperative to take proactive measures to enhance the resilience of drought sensitive crops like rice. Therefore, the present study was carried out to improve the drought stress tolerance in rice through gamma amino butyric acid (GABA) application.MethodsThe experiment was included four GABA concentrations i.e., 0 mM as control, 1 mM, 1.5 mM, and 2 mM, two water levels i.e., 100% and 50% field capacity (referred as FC100 for well-watered and FC50 for drought conditions, respectively), and two fragrant rice cultivars i.e., Super Basmati and Basmati-515.ResultsThe findings unveiled a comprehensive improvement in various parameters with GABA application in fragrant rice under both well-watered (FC100) and water-limited (FC50) conditions, compared to the control. Specifically, GABA induced enhancements were observed in plant height, root length, fresh weight, dry weight, total soluble protein content, and total free amino acid content across both cultivars. Moreover, GABA application significantly improved peroxidase (POD) and catalase (CAT) enzyme activities, alongside elevating anthocyanin levels, while concurrently reducing H2O2 contents in both FC100 and FC50 treatments. Furthermore, the positive impact of GABA extended to morphological traits, with notable increases in panicle length, total tillers and productive tillers per hill, branch and grain numbers per panicle, and 1000-grain weight for Super Basmati and Basmati 515 cultivars under both water regimes, compared to Ck. Similarly, the grain yield increased by 31.01% and 27.32% under FC100 and 36.85% and 27.71% under FC50 in Super Basmati and Basmati-515, respectively, in response to GABA application, compared to Ck. Additionally, principal component analysis (PCA) revealed significant variances attributed to Dim1 and Dim2, with 86.1% and 4.0% of the variance, respectively, across three bi-plots encompassing rice cultivars, water levels, and GABA treatments. Notably, all tested indices, except for H2O2 and non-productive tillers per hill, exhibited positive correlations amongst themselves and with rice yield, further emphasizing the beneficial effects of GABA application on fragrant rice under well-watered and drought conditions.ConclusionsGABA significantly improved fragrant rice performance under both well-watered (FC100) and water-limited (FC50) conditions. Moreover, integrating GABA application into rice cultivation practices could not only improve the crop resilience to drought stress but also potentially benefiting the future food and nutritional security globally. However, however; further research is needed to understand the cellular and molecular mechanisms of the functionality of GABA in fragrant rice, particularly under drought conditions.