Water-soluble Proteins Research Articles

Re-Examination Characterization and Screening of Stripe Rust Resistance Gene of Wheat TaPR1 Gene Family Based on the Transcriptome in Xinchun 32

Pathogenesis-related protein-1 (PR1) encodes a water-soluble protein produced in plants after pathogen infection or abiotic stimulation. It plays a crucial role in plant-induced resistance by attacking pathogens, degrading cell wall macromolecules and pathogen toxins, and inhibiting the binding of viral coat proteins to plant receptor molecules. Compared to model plants, the mechanism of action of PR1 in wheat remains underexplored. In this study, the recently published wheat genome database (IWGSC RefSeq V2.1) was used to identify 83 genes in the TaPR1 gene family. Compared to previous work, the duplicate genes were removed and we corrected misannotated genes. Fourteen TaPR1 genes involved in the wheat–Pst interaction were identified based on RNA sequencing from Xinchun 32. The expression patterns of eight genes were validated using qRT-PCR, and the results showed that PR1 was highly expressed following Puccinia striiformis f. sp. tritici (Pst) infection. This study enhances previous research on wheat PR1, contributing to a more comprehensive understanding of the TaPR1 gene family and providing a reference for the screening of more broad-spectrum and high-resistance wheat populations.

Enhancing Soybean Salt Tolerance with GSNO and Silicon: A Comprehensive Physiological, Biochemical, and Genetic Study

Soil salinity is a major global challenge affecting agricultural productivity and food security. This study explores innovative strategies to improve salt tolerance in soybean (Glycine max), a crucial crop in the global food supply. This study investigates the synergistic effects of S-nitroso glutathione (GSNO) and silicon on enhancing salt tolerance in soybean (Glycine max). Two soybean cultivars, Seonpung (salt-tolerant) and Cheongja (salt-sensitive), were analyzed for various physiological, biochemical, and genetic traits under salt stress. The results showed that the combined GSNO and Si treatment significantly improved several key traits, including plant height, relative water content, root development, nodule numbers, chlorophyll content, and stomatal aperture, under both control and salt stress conditions. Additionally, this treatment optimized ion homeostasis by enhancing the Na/K ratio and Ca content, while reducing damage markers such as electrolyte leakage, malondialdehyde, and hydrogen peroxide. The stress-responsive compounds, including proline, ascorbate peroxidase, and water-soluble proteins, were elevated under stress conditions, indicating improved tolerance. Gene expression analysis revealed significant upregulation of genes such as GmNHX1, GmSOS2, and GmAKT1, associated with salt stress response, while GmNIP2.1, GmNIP2.2, and GmLBR were downregulated in both varieties. Notably, the salt-sensitive variety Cheongja exhibited higher electrolyte leakage and oxidative damage compared to the salt-tolerant Seonpung. These findings suggest that the combination of GSNO and silicon enhances salt tolerance in soybean by improving physiological resilience, ion homeostasis, and stress-responsive gene expression.

Chlorophyll-Based Optogenetics to Control Membraneless Organelles.

Membraneless organelles (MLOs) formed via protein phase separation have garnered significant attention recently due to their relevance to cellular physiology and pathology. However, there is a lack of tools available to study their behavior and control their bioactivity in complex biological systems. This chapter describes a new optogenetic tool based on water-soluble chlorophyll protein (WSCP), a redlight-induced singlet oxygen-generating protein, to control syntheticMLOs. Upon exposure to red light, WSCP generates singlet oxygen, which triggers the crosslinking of the proteins in theMLOs, resulting in their liquid-to-solid phase transition. The effective delivery of chlorophylls enables the successful reconstitution of WSCP in living cells, thusoffering a potential approach to biological regulation at the subcellular level.

Structural bioinformatic study of six human olfactory receptors and their AlphaFold3 predicted water-soluble QTY variants and OR1A2 with an odorant octanoate and TAAR9 with spermidine

Abstract The molecular mechanism of olfaction, namely, how we smell with limited olfactory receptors to recognize exceedingly diverse and large numbers of scents remains unknown despite the recent advances in chemistry, chemical, structural, and molecular biology. Olfactory receptors are notoriously difficult to study because they are fully embedded in the cell membrane. After decades of efforts and significant funding, there are only three olfactory receptor structures known. To understand olfaction, we carried out the structural bioinformatic study of six human olfactory receptors including OR51E1, OR51E2, OR52cs, OR1A1, OR1A2, TAAR9, and their AlphaFold3 predicted water-soluble QTY variants with odorants. We applied the QTY code to replace leucine (L) with glutamine (Q), isoleucine (I) and valine (V) with threonine (T), and phenylalanine (F) with tyrosine (Y) only in the transmembrane helices. Therefore, these QTY variants become water-soluble. We also present the superimposed structures of native olfactory receptors and their water-soluble QTY variants. The superimposed structures show remarkable similarity with RMSDs between 0.441 and 1.275 Å despite significant changes to the protein sequence of the transmembrane domains (43.03%–50.31%). We also show the differences in hydrophobicity surfaces between the native olfactory receptors and their QTY variants. Furthermore, we also used AlphaFold3 and molecular dynamics to study the odorant octanoate with OR1A2 and spermidine with TAAR9. Our bioinformatics studies provide insight into the differences between the hydrophobic helices and hydrophilic helices, and will likely further stimulate designs of water-soluble integral transmembrane proteins and other aggregated proteins.

Phycocyanin Additives Regulate Bacterial Community Structure and Antioxidant Activity of Alfalfa Silage.

Phycocyanin is a water-soluble pigment protein extracted from prokaryotes such as cyanobacteria and has strong antioxidant activity. As a silage additive, it is expected to enhance the antioxidant activity and fermentation quality of alfalfa silage. This study revealed the effects of different proportions of phycocyanin (1%, 3%, 5%) on the quality, bacterial community and antioxidant capacity of alfalfa silage. The results showed that 5% phycocyanin supplementation could maintain dry matter (DM), crude protein (CP) and water-soluble carbohydrate (WSC) content; increase lactic acid (LA) content; decrease pH and butyric acid (BA) and ammonia nitrogen (NH3-N) content; and improve fermentation quality. At the same time, the contents of total antioxidant capacity (TAOC), total phenol content (TP), polysaccharide content (P) and total flavonoid content (F) in the addition group were significantly increased, the antioxidant capacity was enhanced and the abundance of lactic acid bacteria was increased, which was positively correlated with silage quality. Phycocyanin can improve the metabolic function of carbohydrates and amino acids and promote the production of secondary metabolites. The application of phycocyanin broadens the variety of additives for alfalfa silage.

Structural molecular modeling of bacterial integral membrane protein enzymes and their AlphaFold2 predicted water-soluble QTY variants

ContextBeta-barrel enzymes are an important area of study in the field of structural biology. These proteins serve crucial roles, acting as porins, transporters, enzymes, virulence factors, and receptors. Recent research has unveiled a novel role for beta-barrel enzymes in the bacterial integral membrane as sentinels. They remain inactive when the integral membrane is intact but activate to carry out enzymatic catalysis in response to host immune responses and antibiotics that breach this barrier. Understanding their structure and function is pivotal in grasping their sentinel role in the bacterial integral membrane. Here we present our structural molecular modeling analyses on four bacterial integral membrane beta-barrel enzymes: (a) OMPLA, (b) OmpT, (c) PagP from E. coli, and (d) PagL from Pseudomonas aeruginosa. We superposed the structures of native beta-barrel integral membrane enzymes with their AlphaFold2-predicted QTY variant structures that showed remarkable similarity despite the replacement of at least 22.95% amino acids in transmembrane regions, the superposed structures displayed notable structural similarity, indicated by RMSD values ranging from 0.181 Å to 0.286 Å. We also analyze the hydrophobicity patches and the enhanced hydrophilic surfaces. Our research provide insights into the structural similarity of hydrophobic and hydrophilic beta-barrel enzymes, validating the utility of the QTY code for investigating beta-barrel membrane enzymes. Our results not only demonstrate that the QTY code serves as a straightforward tool for designing water-soluble membrane proteins across various biological contexts, but it may also stimulate experiments to validate our molecular modeling studies.MethodsAll the QTY variant beta-barrel enzyme structure prediction was performed using the AlphaFold2 program (https://github.com/sokrypton/ColabFold) following the provided instructions. Computations were carried out on 11th Gen Intel Core i5-11300H processor with 16 GB RAM and Iris Xe Graphics, 512 GB NVMe SSD. The structures are publicly available on the AlphaFold2 database (https://alphafold.ebi.ac.uk) at the European Bioinformatics Institute (EBI). A custom Python script was used to extract the relevant information from the UniProt database. To predict the structures of the QTY variants, AlphaFold2 was utilized. The native sequences for these enzymes were retrieved from UniProt https://www.uniprot.org, and AlphaFold2 structural predictions were performed using the open-source implementation at https://github.com/sokrypton/ColabFold. The predicted variant structures were then superposed with the native structures using PyMOL https://pymol.org/2/ for structural analysis and comparison. This work leverages public databases PDB, UniProt and open-source software AlphaFold2 and PyMOL to computationally model and analyze QTY variant integral membrane beta-barrel enzyme structures.Graphical abstract

Antioxidant properties of the soluble carotenoprotein AstaP and its feasibility for retinal protection against oxidative stress.

Photodamage to the outer segments of photoreceptor cells and their impaired utilization by retinal pigment epithelium (RPE) cells contribute to the development of age-related macular degeneration (AMD) leading to blindness. Degeneration of photoreceptor cells and RPE cells is triggered by reactive oxygen species (ROS) produced by photochemical reactions involving bisretinoids, by-products of the visual cycle, which accumulate in photoreceptor discs and lipofuscin granules of RPE. Carotenoids, natural antioxidants with high potential efficacy against a wide range of ROS, may protect against the cytotoxic properties of lipofuscin. To solve the problem of high hydrophobicity of carotenoids and increase their bioaccessibility, specialized proteins can ensure their targeted delivery to the affected tissues. In this study, we present new capabilities of the recombinant water-soluble protein AstaP from Coelastrella astaxanthina Ki-4 (Scenedesmaceae) for protein-mediated carotenoid delivery and demonstrate how zeaxanthin delivery suppresses oxidative stress in a lipofuscin-enriched model of photoreceptor and pigment epithelium cells. AstaP in complex with zeaxanthin can effectively scavenge various ROS (singlet oxygen, free radical cations, hydrogen peroxide) previously reported to be generated in AMD. In addition, we explore the potential of optimizing the structure of AstaP to enhance its thermal stability and resistance to proteolytic activity in the ocular media. This optimization aims to maximize the prevention of retinal degenerative changes in AMD.

Investigating the Presence of Selenoneine, Ergothioneine, and Selenium-Containing Biomolecules in Fish and Fish-Derived Commercial Products.

Two potent antioxidants, selenoneine and ergothioneine, have been determined simultaneously for the first time in the muscle of highly consumed fish and in fish-derived products. The extraction methods were optimized, and their subsequent analysis was performed by HPLC-ESI-MS/MS. Best extraction efficiency (106 ± 3 and 104 ± 5%) was attained by performing a simple aqueous extraction containing 100 mmol L-1 ammonium acetate or ammonium formate as extractants. Selenoneine and ergothioneine were simultaneously detected in tuna (0.306 ± 0.006 and 3.5 ± 0.2 μg g-1) and swordfish (0.14 ± 0.02 and 1.1 ± 0.4 μg g-1) muscle tissues, while in fish roe and in farmed salmon, only ergothioneine was detected (with contents ranging 0.03-3.3 μg g-1). Moreover, the presence of their respective methylated forms was also considered. Additionally, Se-containing biomolecule profiles from water-soluble proteins were obtained by SEC-ICP-MS analysis. Results revealed similar profiles between fish and fish roe, whereas for ultraprocessed fish products, Se seems to be mostly associated with low-molecular-weight biomolecules. The results included in this work may contribute to a better understanding of the relations between selenoneine and ergothioneine in fishery products as well as their fate and potential modifications of Se-containing biomolecule profiles during fish processing.

Upcycling of melanoidin-rich Chinese distilled spent grain through solid-state fermentation by Aspergillus awamori

This study investigated the upcycling of distilled spent grain (DSG), a melanoidin-rich by-product of the Chinese liquor industry, via fungal solid-state fermentation (SSF). Two fungi, Aspergillus oryzae and Aspergillus awamori, were tested, with A. awamori growing better on DSG than A. oryzae. SSF with A. awamori increased the concentration of water-soluble protein and phenolic compounds in DSG extracts by 46.5 % and 52.5 %, respectively, and reduced melanoidin level by 73.5 % w/w of DSG, suggesting A. awamori could metabolize melanoidins. Submerged fermentation (SmF) using isolated DSG melanoidins as sole carbon and nitrogen sources confirmed this observation. After 3 days of fermentation, A. awamori and A. oryzae biomass reached 2.5 g/L and 1.5 g/L, quenching melanoidin color by 24.4 % and 12.4 %, respectively. SmF by A. awamori also released free arabinose, glucose, and xylose. Data highlighted the possibility of converting melanoidins into edible mycelia resources, potentially applicable to various melanoidin-rich food by-products.

УДОСКОНАЛЕННЯ ТЕХНОЛОГІЇ КЕКСІВ З ВИКОРИСТАННЯМ ЛЮПИНОВОГО БОРОШНА

The article is devoted to improving the technology of cupcakes by introducing lupine flour into their recipe. Lupine flour has been determined to be free of cholesterol, gluten and stomach irritants; modern sweet varieties do not contain alkaloids. Due to its low starch content and high dietary fiber content, it has a very low glycemic index (GI) and is recommended as an element in the diet of diabetics or people who want to lose weight, lower blood cholesterol and triglycerides and regulate blood pressure. Lupine flour contains up to 40% protein. Its fractional composition contains salt- and water-soluble proteins - 82-85%, alkali-soluble - 5-8%, insoluble fraction - 9-10%, alcohol-soluble proteins are completely absent. In terms of amino acid composition, lupine protein has a high content of lysine, threonine and leucine compared to other proteins contained in legumes. These amino acids have a positive effect on the young body (lysine and threonine) and are used in the treatment of diseases such as liver disease and anemia (leucine). In the work, 3 samples of cupcakes were developed with a partial replacement of wheat flour with lupine flour. After baking, samples with the addition of lupine flour were determined by organoleptic quality indicators, namely taste, smell, shape, texture, surface, structure and cross-sectional view. Research data showed that the addition of lupine flour in the amount of 15.0%...30.0% significantly improved the texture of the muffins compared to the control sample. The sample of the cake with a partial replacement of wheat flour with lupine flour meets the requirements of a healthy diet to the greatest extent due to the increased content of proteins (22.83%) and the reduced content of carbohydrates (36.33%). In general, the analysis of the chemical composition according to the content of proteins, fats, and carbohydrates showed the advantage of the improved recipes of the "Stolichny" cake, in particular, according to the content of the amino acid composition of proteins and fats, as well as reduced calorie content. Based on the results of the research, it can be concluded that the improved muffins expand the assortment of flour confectionery products for healthy nutrition with the content of essential amino acids in their optimal ratio.

The effects of different processing treatments to active ingredients, nutrients, volatile components and antioxidant activity in Poria cocos wolf

The study compared the triterpenoid ingredients, polysaccharide, protein, amino acid, and volatile components of PC. The PC was treated with traditional sweating (TST), steaming sweating for 1 to 4 h (SS1h-SS4h, Δ = 1 h) and non-sweating (NS). The results showed the content of six triterpenoids (1.03 mg/g), water-soluble protein (0.33 mg/g) and total triterpenoid (3.81 mg/g) were the highest in NS; the content of alkali-soluble polysaccharide (51.96 mg/g) was the highest in SS1h; the content of crude protein (16.18 mg/g) and total amino acid (53.07 mg/g) were highest in TST. Moreover, the predominant volatile component of SS1h was hexanal, SS2h-SS4h and TST were Linalool, NS was D-limonene. Ulteriorly, the correlation analysis showed antioxidant effect of PC may be related to the content of alkali-soluble polysaccharide, Furan-2-pentyl, and 2-Octenal, PCA result indicated the score of SS1h-treated PC was the highest. This study could provide a new solution for the industrial production of PC.

Whole-genome sequencing and assessment of a novel protein- and gossypol-degrading Bacillus subtilis strain isolated from intestinal digesta of Tibetan Pigs

BackgroundWith the rapid development of animal husbandry, the demand for protein feed resources is increasing. Cottonseed meal (CSM) and soybean meal (SBM) are rich sources of protein. However, their application is limited due to the existence of anti-nutrients, which can be harmful to the digestion and absorption. A strain of Bacillus subtilis (Mafic-Y7) was isolated from digesta of intestines of Tibetan pigs. The strain showed high protease activity, which helps in degrading proteinic anti-nutritional factors in grain meal and in vitro degradation of free gossypol. In order to better understand this isolated strain, whole genome of Mafic-Y7 strain was sequenced and analyzed. Different effects on various grain meals were identified.ResultThe GC-depth Poisson distributions showed no bias suggesting high-quality genome assembly of Mafic-Y7. The whole genome sequencing showed that one chromosome with 4,248,845 base pairs(bp)and the genes total length with 3,736,524 bp was predicted in Mafic-Y7. Additionally, Mafic-Y7 possessed 4,254 protein-coding genes, and several protease genes were annotated by aligning them with databases. There are 55 protease genes, one phytase gene and one laccase gene were annotated in the gene sequence of Mafic-Y7. The average nucleotide identity between Mafic-Y7 and the GCA-000009045.1 homologous genome was 0.9938, suggesting a close genetic relationship between them at the species level. Compared with the closest four whole genomes, Mafic-Y7 was annotated the most abundant of protease genes (55 genes). The fermentation supernatant of Mafic-Y7 could increase the content of small peptides, water-soluble proteins, and acid-soluble proteins in vitro by 411%, 281% and 317% in SBM and 420%, 257% and 338% in CSM. After fermentation in grain meal by Mafic-Y7, the degradation rate of anti-nutritional factors in SBM, such as trypsin inhibitor, glycinin, and β-conglycinin was greater than 70%, and lectin was greater than 30%. The degradation rates of anti-nutritional factors in CSM, such as gossypol and phytic acid, were 82% and 26%, respectively.

The interplay of excitonic delocalization and vibrational localization in optical lineshapes: A variational polaron approach.

The dynamics of molecular excitonic systems are complicated by a competition between electronic coupling (which drives delocalization) and vibrational-electronic (vibronic) interactions (which tend to encourage electronic localization). A particular challenge of molecular systems is that they typically possess a large number of independent vibrations, with frequencies often spanning the entire spectrum of relevant electronic energy gaps. Recent spectroscopic observations and numerical simulations on a water-soluble chlorophyll-binding protein (WSCP) reveal a transition between two regimes of vibronic behavior, a Redfield-like regime in which low-frequency vibrations respond to a delocalized excitonic state, and a Förster-like regime where high-frequency vibrations act as incoherent excitations on individual pigments. Although numerical simulations can reproduce these effects, there is a need for a simple, systematic theory that accurately describes the smooth transition between these two regimes in experimental spectra. Here we address this challenge by generalizing the variational polaron transform approach of [Bloemsma et al., Chem. Phys. 481, 250 (2016)] to include arbitrary bath densities for systems with or without symmetry. We benchmark this theory against both numerical matrix-diagonalization methods and experimental 77K fluorescence spectra for two WSCP variants, obtaining quite satisfactory agreement in both cases. We apply this theory to offer an explanation for the large loss in apparent electronic coupling in the WSCP Q57K mutant and to examine the likely impact of the interplay between excitonic delocalization and vibrational localization on vibrational sideband shapes and apparent coupling strengths in high-resolution optical spectra for chlorophyll-protein complexes such as WSCP.

Enhancement of nutritional, organoleptic, and umami qualities of chicken soup induced by enzymatic pre-treatment of chicken

To enhance both the quality and cooking efficiency of chicken soup, the effect of enzymatic pre-treatment of chicken on the quality of the chicken soup was investigated in this study. Results indicated that the application of enzymatic pre-treatment markedly enhanced the sensory attributes, physicochemical properties, and nutritional value, compared with the control sample. Specifically, the chicken soup with enzymatic pre-treatment exhibited a significant increase in the concentration of water-soluble proteins, 5′-nucleotides, and umami amino acids (P < 0.05). There were 52 umami peptides identified in enzymatic pre-treatment chicken soup, and eight abundant umami peptides were chosen for molecular docking. The analysis revealed that the primary active sites for interaction between the umami peptide and the T1R1/T1R3 receptor were ASP-30, GLU-27, and MET-342. Therefore, enzymatic pre-treatment of chicken facilitates high-value-added chicken soup products and provides a new approach to improve the quality and efficiency of chicken soup.

Адаптация форм Pinus sylvestris с разным цветом семян на избыточно увлажненных почвах

Adaptive changes in biochemical parameters of different pine forms under conditions of constant excessive soil moisture in the northern latitudes of the European part of Russia have been studied. The influence of seasonal variability on the dynamics of the photosynthetic pigment complex of pine forms with different seed colours has been shown. It has been established that elevated temperatures in early autumn contribute to the accumulation of chlorophyll, and this can negatively affect the hardening of trees in preparation for overwintering. The proportion of chlorophylls localized in the light-harvesting complexes of chloroplasts fluctuates from May to November from 43 to 60 %, which is associated with the adaptation of the photosynthetic apparatus of trees of different forms to the light conditions of high latitudes and other environmental factors. It has been determined that anthocyanins accumulate significantly more in pine needles in autumn, which increases their antioxidant role in this season. It has been revealed that peroxidase activity in 1-year-old needles increases in the autumn period. This can be considered as a protective reaction of different forms of pine, preventing the development of uncontrolled processes with a limited oxygen supply to the organs. A significant new formation of water-soluble proteins in pine needles with dark-coloured seeds has been detected due to the deterioration of weather conditions. This form, compared to pine with light seeds, probably reacts more strongly to the effect of stress factors that increase hypoxia of the root system. It has been concluded that the concentration of proline in needles is a very variable indicator, reacting sharply to the action of stress factors. No general trends in the seasonal dynamics of the indicator have been identified. It has been established that the content of ascorbic acid in the needles of trees of different forms of pine in late spring is significantly lower than in the summer and autumn seasons. This indicates the development of protective mechanisms to prevent oxidative stress under adverse weather conditions.

Quantitative trait locus mapping for water-soluble protein content in soybean across six environments

Quantitative trait locus mapping for water-soluble protein content in soybean across six environments

Physiological research of young Russian sturgeons in modern ecological conditions of the Caspian sea

In the Volga-Caspian fisheries basin, artificial reproduction of sturgeon species is the primary source of replenishing their natural populations. The aim of this study is to conduct physiological research on juvenile Russian sturgeon (Acipenser gueldenstaedtii) in the western part of the Northern Caspian Sea, to establish the features of fish homeostasis. The physiological condition of the specimens was studied using a set of physiological and biochemical parameters. Hematological, biochemical, and morpho-histological parameters were evaluated. In the blood of the fish, the contents of hemoglobin, total protein, glucose, inorganic phosphorus, calcium, creatinine, bilirubin, total lipids, cholesterol, and triglycerides were determined. In the muscle tissue of juvenile Russian sturgeon, the physiological and biochemical indicators studied included the content of the main reserve substances of the body — total lipids and water-soluble protein. Histological methods were used to assess the morpho-functional state of the gills. The variability of physiological and biochemical parameters in juvenile Russian sturgeon was calculated using descriptive statistics based on parametric and non-parametric criteria in the blood and muscles. According to the results of correlation statistical analysis, significant changes were observed in the tissues of the sturgeon juveniles, aimed at providing the body with sources of energy and nutrients used for the functioning of body tissues and serving as reserve stocks, as well as maintaining regulatory mechanisms of metabolism and its changes depending on fluctuating environmental conditions. The morphological examination of the gills revealed vascular disorders, hyperplasia, swelling, and hypertrophy of the respiratory epithelium cells, corresponding to borderline disturbances from mild to moderate damage, which was the organ’s response to external environmental influences.

The Effects of Substrates and Sonication Methods on the Antioxidant Activity of Kefir Postbiotics

Sonoporation stimulates cell growth as it improves the permeability of the membrane and increases the uptake of impermeable molecules in the extracellular matrix. We evaluated the effects of substrates (whey, whole, and skim milk) and ultrasonic treatments (ultrasonication and thermosonication) on the antioxidant activity (AA) of water-soluble kefir postbiotics (WSKPs). The samples were evaluated in terms of antioxidant activity (ABTS, DPPH, FRAP, and ORAC), water-soluble protein content, proteolysis (SDS-PAGE profiles), and cell membrane permeability. The levels of AA in all WSKPs depended on the substrate and method of obtaining them. However, the WSKPs from whey had higher antioxidant activity with DPPH (11.11 mg TE/100 mL), ABTS (12.77 mg TE/100 mL), and FRAP (5.18 mg TE/100 mL). Also, the WSKPs from whey had the highest values for water-soluble protein (1.45–1.32 mg/mL) and proteolysis degree and the lowest percentage of dead cells (11.4–28%). These results suggest that the production of WSKPs from whey might add value to whey production. Furthermore, WSKPs have potential as a functional ingredient in the production of beverages or foods with antioxidant activity.

Exploring mercury detoxification in fish: The role of selenium from tuna byproduct diets for sustainable aquaculture

Exposure to mercury (Hg) through fish consumption poses significant environmental and public health risks, given its status as one of the top ten hazardous chemicals. Aquaculture is expanding, driving a surge in demand for sustainable aquafeeds. Tuna byproducts, which are rich in protein, offer potential for aquafeed production, yet their use is challenged by the high content of heavy metals, particularly Hg. However, these byproducts also contain elevated levels of selenium (Se), which may counteract Hg adverse effects. This study examines the fate of dietary Hg and Se in an aquaculture model fish. Biomolecular speciation analyses through hyphenated analytical approaches were conducted on the water-soluble protein fraction of key organs of juvenile rainbow trout (Oncorhynchus mykiss) exposed to various combinations of Hg and Se species, including diets containing tuna byproducts, over a six-month period. The findings shed light on the dynamics of Hg and Se compounds in fish revealing potential Hg detoxification mechanisms through complexation with Hg-biomolecules, such as cysteine, glutathione, and metallothionein. Furthermore, the trophic transfer of selenoneine is demonstrated, revealing novel opportunities for sustainable aquafeed production. Understanding the interactions between Hg and Se in aquaculture systems is crucial for optimizing feed formulations and mitigating environmental risks. This research contributes to the broader goal of advancing sustainable practices in aquaculture while addressing food security challenges.

Controlling Vibronic Coupling in Chlorophyll Proteins: The Effects of Excitonic Delocalization and Vibrational Localization.

Vibrational-electronic (vibronic) coupling plays a critical role in excitation energy transfer in molecular aggregates and pigment-protein complexes (PPCs). But the interplay between excitonic delocalization and vibronic interactions is complex, often leaving even qualitative questions as to what conceptual framework (e.g., Redfield versus Förster theory) should be used to interpret experimental results. To shed light on this issue, we report here on the interplay between excitonic delocalization and vibronic coupling in site-directed mutants of the water-soluble chlorophyll protein (WSCP), as reflected in 77 K fluorescence spectra. Experimentally, we find that in PPCs where excitonic delocalization is disrupted (either by mutagenesis or heterodimer formation), the relative intensity of the vibrational sideband (VSB) in fluorescence spectra is suppressed by up to 37% compared to that of the native protein. Numerical simulations reveal that this effect results from the localization of high-frequency vibrations in the coupled system; while excitonic delocalization suppresses the purely electronic transition due to H-aggregate-like dipole-dipole interference, high-frequency vibrations are unaffected, leading to a relative enhancement of the VSB. By comparing VSB intensities of PPCs both in the presence and absence of excitonic delocalization, we extract a set of "local" Huang-Rhys (HR) factors for Chl a in WSCP. More generally, our results suggest a significant role for geometric effects in controlling energy-transfer rates (which depend sensitively on absorption/fluorescence line shapes) in molecular aggregates and PPCs.