High-moisture extrusion and formulation-induced structural differences are associated with differences in dynamic gastric disintegration and subsequent intestinal protein hydrolysis in meat analogues; however, the underlying mechanisms remain unclear. This study compared the in vitro digestive behaviours of high-moisture-extruded meat analogues incorporated with 20% air-classified quinoa flour (QF) (MA-20QF), QF-free analogues (MA-0QF) and cooked chicken. Samples were subjected to dynamic gastric digestion (240 min) followed by static small intestinal digestion (120 min). Gastric-emptied digesta collected at 60 and 180 min were further digested in the intestinal phase. Gastric pH, solid and protein retention, particle size, protein degradation, degree of hydrolysis (DH) and peptide molecular weight distribution were analysed. QF incorporation reduced structural anisotropy, weakened textural properties and accelerated gastric acidification (ΔpH = 0.2784/min for MA-20QF, 0.2491/min for MA-0QF and 0.2431/min for chicken; R[2] > 0.995). During gastric digestion, meat analogues exhibited slower solid and protein emptying than chicken and retained larger particle sizes. After 240 min, meat analogues fragmented into 10-100 μm particles, whereas chicken fragmented into 5-10 μm particles. DH followed the order of MA-20QF > chicken > MA-0QF. Furthermore, gastric digesta collected at 180 min exhibited higher DH in the subsequent intestinal phase than that collected at 60 min. Although gastric digestion predominantly produced peptides with a molecular weight of 1000-5000 Da for all samples (>93%), intestinal digestion drove extensive hydrolysis. Cooked chicken generated the largest proportion of <1000-Da peptides, followed by MA-20QF and MA-0QF. Overall, formulation-induced matrix structure and gastric pre-processing were associated with differences in gastrointestinal proteolysis, highlighting the importance of formulation strategies in modulating the digestive behaviour of plant-based meat analogues.

Bioconversion with black soldier fly larvae (BSFL) is an efficient method for disposing of chicken manure. However, large amounts of ammonia (NH3) are released during bioconversion, resulting in significant nitrogen loss. Previous studies generally neglected the synergistic regulation of ammonification and ammonia assimilation for mitigating NH3 emissions. In this study, a novel biotechnological strategy combining propionic acid, probiotics, and glucose (PPG) was established. Specifically, acidification combined with Bacillus was applied to inhibit ammonification, while glucose was added to regulate substrate carbon to nitrogen ratio (C/N) and promote ammonia assimilation during BSFL mediated chicken manure bioconversion. The results showed that PPG significantly reduced NH3 emissions by 70.98 % compared to the control (CK) (p < 0.05). Metagenomics was used to analyze microbial regulatory mechanisms. PPG treatment resulted in a significantly higher relative abundance of ammonia assimilation gene (glnA) and lower abundance of ammonification associated genes (ureC, glsA, gcvT, gudB) (p < 0.05). These observations could be attributed to microbial community perturbations. Genera including Proteiniphilum and Petrimonas were primary contributors to ammonification and ammonia assimilation in CK, whereas genera such as Limosilactobacillus and Romboutsia dominated these two nitrogen metabolic functions in PPG. Further, the applicability of PPG strategy was effectively verified in high-density BSFL cultivation system. Finally, application of cost-optimized biotechnological strategy using calcium propionate and industrial carbon sources achieved a net profit of 10.81 USD/t. In summary, this study provided a promising biotechnological strategy for NH3 mitigation and elucidated the microbial response mechanism underlying the synergistic regulation of ammonification and ammonia assimilation.

Solar photoaging endows maize leaf residues with persistent redox activity through the spontaneous generation of oxygen-centered environmentally persistent free radicals (EPFRs). Upon soil incorporation, these long-lived radicals and their derived dissolved organic matter (DOM) act as electron donors that promote Fe(III) reduction to Fe(II), followed by Fe(II) reoxidation and reprecipitation, thereby promoting reduction-initiated Fe(III)/Fe(II) redox cycling. This process profoundly shapes soil properties by expanding the organic carbon pool, yet it accelerates soil acidification and triggers root-localized oxidative stress, which induces lipid peroxidation and partially offsets the growth-promoting effect of biomass amendment. Concurrently, the persistent oxidative pressure and oxygen consumption reshape the indigenous soil microbiome, shifting it toward iron-reducing consortia (e.g., Gammaproteobacteria and Bacillus circulans). Crucially, this radical-Fe process is associated with the conversion of labile ion-exchangeable Cd into more stable Fe/Mn oxide-bound fractions. Consequently, heavy metal translocation in the soil-plant system is effectively blocked, mitigating root and shoot Cd accumulation in Ipomoea aquatica by up to 50%. This study demonstrates a novel nature-based strategy coupling organic waste recycling with sustainable in-situ heavy metal remediation.

Age-related deterioration of skeletal muscle contributes to loss of mobility, frailty, and disability. Altered autophagy-lysosome competence has been proposed as a mechanism linking impaired proteostasis, mitochondrial damage, inflammation, and regenerative failure to sarcopenia. Chronological muscle aging and clinically defined sarcopenia overlap, but evidence from healthy aging, frailty, disuse, cachexia, obesity, or chronic disease cannot be treated as interchangeable. This narrative review examines how lysosomal acidification, degradative capacity, biogenesis, and turnover influences autophagic flux in aging muscle and evaluates the strength of evidence across experimental models and human studies. Genetic and pharmacological studies show that severe disruption of autophagy or specific lysosomal functions can cause myofiber damage, mitochondrial impairment, defective regeneration, and weakness. However, direct evidence that lysosomal acidification, fusion, hydrolase activity, membrane integrity, recycling, cargo degradation, or completed autophagic flux is impaired in aging human muscle remains limited. Much of the human literature relies on static abundance of LC3-II, SQSTM1/p62, lysosomal proteins, or transcriptional signatures, which cannot distinguish increased autophagosome formation from impaired degradation. We therefore separate causal experimental evidence from human associations and focus on V-ATPase, TMEM175, LAMP proteins, TFEB/TFE3, lysophagy, and crosstalk with mitophagy and the ubiquitin-proteasome system. Exercise improves clinically relevant outcomes in older adults, but mediation through completed autophagic flux has not been established. Recent trials of metformin and once-weekly sirolimus did not improve prespecified functional outcomes in the tested populations and regimens, whereas urolithin A produced endpoint-specific signals while missing key primary outcomes.

Climate-driven warming, oxygen loss, acidification, salinity change, and extreme events increasingly challenge fish performance and persistence. This review mapped the global development of fish-adaptation research from 1975 to 2025 using 83,614 articles and 4,272,627 cited references. Publication, collaboration, keyword, citation-burst, and reference co-citation analyses were integrated with critical biological synthesis. Annual output increased at an estimated 9.02% per year from 1975 to 2024, although proposed boundaries at 2010 and 2019 were not statistically significant publication-growth breakpoints and were retained only as interpretive periods. Research evolved cumulatively from salmonid and organismal physiology toward climate-oriented, molecular, disease, genomic, and field-monitoring approaches. Global output and network connectivity remained concentrated among a limited number of countries and institutions, while established model species continued to dominate major research themes. Citation bursts also showed strong methodological visibility, which should not be equated with biological importance. Emerging priorities include multi-stressor experiments, sensitive life stages, tropical and other underrepresented systems, long-term monitoring, environmental DNA, and stronger linkage of molecular responses to demographic outcomes. The evidence is limited by single-database coverage, English-language and document-type restrictions, broad search terminology, metadata inconsistencies, citation bias, and parameter-dependent network construction. Equitable funding, capacity building, and research leadership in climate-vulnerable regions are needed to improve the biological and management relevance of future fish-adaptation research.

Brain-type creatine kinase (CK-BB) buffers local ATP demand through reversible phosphotransfer between ATP and phosphocreatine, yet how this soluble metabolic enzyme couples to dynamic membrane compartments remains unclear. Here, we integrate immunofluorescence microscopy, DEER spectroscopy, hydrogen-deuterium exchange and native mass spectrometry, DEER- and AlphaFold-guided modeling, and long-timescale molecular dynamics to define the acid- and substrate-regulated conformational landscape of human CK-BB. Acidification redistributes endogenous and recombinant CK-BB from a diffuse cytosolic pool to punctate vesicular structures and membrane ruffles. DEER and modeling reveal a spatially asymmetric dimer in which the convex surface remains comparatively restrained, whereas the concave catalytic-regulatory surface samples pH- and substrate-dependent conformational intermediates. We identify progressive dimer opening as a novel regulatory mechanism by which acidic pH and substrate binding increase dynamics across the convex surface and NTD-NTD interface and sensitize the His191/Ser199 module to graded pH-dependent exchange. Substrate binding buffers acid-induced deprotection while preserving localized dynamics near this regulatory interface. Together, these data support a model in which protonation and substrate occupancy generate membrane-competent CK-BB conformations, coupling local ATP regeneration to curved vesicular and actin-remodeling membranes.

In milk, casein proteins are oriented into spherical micellar structures. During gastric digestion, casein is destabilized via the pepsin-induced cleavage of κ-casein, forming a clot that certain populations (e.g., infants, elderly) have a difficult time digesting. Emulsifying salts (ES), such as sodium citrate (SC) and sodium hexametaphosphate (SHMP), are used in some dairy products (e.g., protein-fortified beverages, infant formula) and serve several beneficial functions including protein stabilization. As an investigative study, this research aims to determine whether SC or SHMP addition (1-100 mM) impact the pepsin-mediated hydrolysis of casein proteins by monitoring the interaction between milk proteins and pepsin in 2 distinct acidification stages: (1) high pH, reflecting infant or early-stage adult digestion, and (2) low pH, representing late-stage adult digestion. The high pH stage (pH 6.0), represented by the initial interaction of milk within the infant or adult gastrointestinal tract, is characterized by protein destabilization and clotting. During this stage, rheology was used to determine clotting kinetics, protein clots were periodically extracted and weighed, and gel electrophoresis was used to monitor κ-casein hydrolysis. The low pH stage (pH 2.2) corresponds to when the milk system has reached typical gastric acidity, and the rate of protein hydrolysis during this stage was monitored by gel electrophoresis. During the high pH stage, the control acidified skim milks formed a strong clot with a relative strength of 304.9 ± 40.6 Pa after 30 min. However, the acidified skim milks containing 10 or 100 mM SC failed to form any pepsin-induced clot, reflected by consistently low storage modulus values (<0.70 Pa) and lack of clot separation. In the low pH stage, pepsin-induced hydrolysis occurred in all samples, yet the 100 mM SC-containing sample had a reduced level of casein hydrolysis after 15 min. In contrast, samples with SHMP (10 and 100 mM) had severely inhibited hydrolysis rates compared with the control skim milks, reflecting SHMP-induced pepsin inactivation. Specifically, all of the casein was hydrolyzed in the control skim milks after 60 min, while 40.5 ± 14.5% and 43.5 ± 6.7% intact casein remained in the samples containing 10 mM and 100 mM of SHMP, respectively. These results indicate that SC and SHMP impact the pepsin-induced hydrolysis of acidified skim milk systems, and these differences are dependent on ES type and concentration. By resisting clotting, ES addition might allow for a faster transit rate through the gastric digestion phase and offer options for populations that struggle to metabolize casein clots, but there is a need to further investigate digestion and nutrient absorption using more advanced digestion protocols (e.g., INFOGEST).

Deoxynivalenol (DON) is a widespread mycotoxin contaminating cereal grains and animal feed, posing significant risks to livestock health and food safety. However, the molecular mechanisms underlying DON-induced nephrotoxicity remain poorly understood. In this study, we identify cuproptosis as a critical driver of DON-induced nephrotoxicity in chickens and investigate the protective role of nano-selenium (Nano-Se). DON exposure disrupted copper homeostasis and induced cuproptosis, as evidenced by dysregulation of FDX1, LIAS, and DLAT, resulting in mitochondrial oxidative damage and electron transport chain (ETC) dysfunction. Excessive mitochondrial reactive oxygen species (mtROS) further impaired lysosomal acidification, resulting in lysosomal membrane permeabilization (LMP) and blockade of mitophagic flux, ultimately triggering a robust inflammatory response. Nano-Se supplementation effectively mitigated DON-induced renal injury by suppressing cuproptosis, restoring mitochondrial redox balance, preserving ETC function, rescuing lysosomal function, re-establishing mitophagic flux, and attenuating inflammatory responses in vivo and in vitro. Mechanistically, pharmacological modulation targeting copper levels, mtROS generation, or mitophagic flux abolished the protective effects of Nano-Se. Collectively, these findings reveal that DON induces nephrotoxicity via the cuproptosis-mtROS-mitophagy axis and that Nano-Se ameliorates DON-induced renal inflammation by suppressing cuproptosis, reducing mtROS accumulation, and restoring mitophagic flux. This study provides a mechanistic basis for the use of Nano-Se as a potential therapeutic agent against mycotoxin-associated renal injury, with implications for environmental health risk assessment and livestock production.

Mycobacterium tuberculosis (Mtb) cultured in minimal medium at acidic pH arrests growth when provided specific single carbon sources, including glycerol, propionate, and lactate, a phenomenon we refer to as acid growth arrest. To define the mechanisms of acid growth arrest on lactate, we selected transposon mutants that grew under these conditions. Five mutants carried insertions in phoT or pstC2, which encode components of a phosphate ABC transporter. Depleting phosphate restored Mtb growth in minimal medium supplemented with lactate at acidic pH, demonstrating that growth arrest on lactate depended on phosphate. The combination of lactate and phosphate at acidic pH acidified the cytoplasm to below pH 6.7, whereas the phoT mutant maintained a cytoplasmic pH > 7.2. Lactate slightly decreased membrane potential in a dose-dependent manner in wild-type Mtb, whereas the phoT mutant maintained a higher membrane potential. Transcriptional profiling identified a lactate-associated PMF stress signature, including upregulation of electron transport chain genes. Together, these findings associate lactate- and phosphate-dependent cytoplasmic acidification with proton motive force (PMF) stress and acid growth arrest. The phoT mutant grown in lactate at acidic pH upregulated the senX3/regX3 regulon. Using a regX3 mutant, we found that growth on lactate under low-phosphate conditions required regX3. We propose a model in which (1) acidic pH, lactate, and phosphate together modulate cytoplasmic pH homeostasis and are associated with PMF stress and acid growth arrest; and (2) low phosphate induces SenX3-RegX3 activity, which may alter cell-envelope physiology through ESX-5- and PE/PPE-dependent pathways and promote growth on lactate at acidic pH.

Potassium solubilizing bacteria (KSB) represent a sustainable strategy for enhancing soil K bioavailability through the dissolution of K-bearing minerals, thereby facilitating nutrient cycling. However, the multifaceted biochemical mechanisms driving mineral weathering remain partially understood. The present study explores the K solubilization characteristic and mechanisms of KSB by analyzing the organic acids they metabolize and their interactions with mineral surfaces. Over 30 d, the strain S1 classified to genus Burkholderia achieved a maximum soluble K+ concentration of 39.8 mg/L, representing a 4.5-fold increase over abiotic controls. Mechanistic analysis revealed a synergistic "dual-attack" strategy: continuous acidification (pH 6.42 to 3.82) promoted proton-driven K+ release, while the dominant secretion of citric and malic acids facilitated ligand-mediated complexation of structural cations, destabilizing the aluminosilicate framework. Additionally, the temporal accumulation of polar and acidic amino acids likely served as biogenic regulators, enhancing bacteria-mineral adhesion and interface interactions. Scanning electron microscopy corroborated these chemical findings, revealing extensive surface etch pits and edge exfoliation. These results suggest that the synergistic interaction of proton attack, ligand-mediated chelation, and amino acid-assisted micro-environment regulation drives mineral weathering. This study provides a comprehensive structural framework for KSB-mediated nutrient mobilization, highlighting the potential of Burkholderia as an efficient bio-fertilizer for potassium-deficient soils.

Acidification, nutrient deficiency, and poor carbon pool stability are key bottlenecks restricting the sustainable development of agriculture in lateritic red soils. In this study, we isolated strains GC05 (Paracoccus communis) and GC07 (Advenella kashmirensis). A composite microbial consortium was constructed and then combined with a biochar-montmorillonite-chicken manure carrier to produce an organic-inorganic composite microbial inoculant. After applying the inoculant to acidic lateritic red soil, we investigated its mechanisms in simultaneously ameliorating acidic lateritic red soil and driving soil organic carbon stabilization. After a 30-day incubation, the inoculant ameliorated the soil environment and enhanced both nutrient availability and carbon stability. Soil pH increased from 4.86 to 5.76, the ratio of recalcitrant carbon to total organic carbon increased from 0.72 to 0.86. The inoculant promoted the enrichment of carbon assimilation-dominant functional microbial taxa. Microbial carbon use efficiency increased from 0.02 to 0.41, and the metabolic focus shifted from enzymatic depolymerization and catabolism to biomass synthesis and anabolism. Structural equation modeling further suggested that microbial biomass exerted a dominant direct effect on the stable soil carbon pool, driving the conversion of labile organic carbon into recalcitrant organic carbon via biomass synthesis and microbial necromass accumulation, which constituted an early-stage microbial carbon pump. This study provides a theoretical foundation and practical strategy for the development of bioaugmented technologies with potential for long‑term carbon sequestration in acidic lateritic red soils.

Canastra artisanal Minas cheese is a traditional Brazilian raw-milk cheese whose fermentation relies on "pingo", an endogenous whey culture that harbors autochthonous lactic acid bacteria (LAB) with technological relevance. This study evaluated the safety and technological properties of LAB isolated from pingo and cheeses from Serra da Canastra region, Brazil. Among 199 presumptive LAB isolates screened for hemolytic activity, mucin degradation, and antibiotic susceptibility, 116 met the preliminary safety criteria. Rep-PCR and partial 16S rRNA gene sequencing revealed 16 genetic groups, mainly represented by Streptococcus lutetiensis (32%), Lactiplantibacillus plantarum (28%), Lpb. paraplantarum (14%), Lactococcus lactis (12%), and Leuconostoc mesenteroides (12%). Vancomycin resistance genes were not detected, whereas biogenic amine-related genes were identified in some strains, and Enterococcus durans 14A3 produced tyramine in vitro. Technological characterization showed variability in acidification capacity (ΔpH/t24 = 0.010-0.061), proteolytic and lipolytic activities, diacetyl production and enzymatic profiles. Genes associated with bacteriocin production, adhesion, and γ-aminobutyric acid (GABA) synthesis were also detected in selected strains. The integration of safety and technological traits identified Lpb. plantarum 2B3 and L. lactis 6D5 as the most promising candidates, combining favorable safety profiles with consistent technological characteristics. These findings highlight the potential of the autochthonous microbiota of Canastra artisanal Minas cheese as a source of adjunct cultures for artisanal dairy production, while reinforcing the importance of strain-level safety assessment.

The vacuolar ATPase (V-ATPase) is essential for lysosomal acidification and autophagy, and its activity is regulated by nutrient-sensitive reversible assembly of its V1 and Vo domains. While mTORC1 is known to inhibit V-ATPase assembly, the precise molecular mechanisms remain incompletely understood. Here, using TurboID-based proximity labeling and quantitative mass spectrometry, we identified the R2TP complex subunits RPAP3 and PIH1D1 as novel autophagy-responsive interactors of the V-ATPase V1A subunit (encoded by ATP6V1A). We found that mTORC1 inhibition disrupts the R2TP-V1A interaction, promoting the relocation of the V1 domain to lysosomes and its assembly with the Vo domain to form active proton pumps. Functionally, knockdown of RPAP3 or PIH1D1 enhanced autophagic flux, increased lysosomal proteolytic activity, and promoted the clearance of soluble α-synuclein in a cellular model of Parkinson's disease (PD). Our study reveals the R2TP complex as a critical molecular switch that couples mTORC1 signaling to V-ATPase assembly and lysosomal function, thereby identifying a new pathway for regulating lysosomal catabolism with significant therapeutic potential for neurodegenerative disorders.

Direct sample extraction methods suitable for lipids such as desorption electrospray ionization (DESI), rapid evaporative ionization mass spectrometry (REIMS), and liquid extraction surface analysis (LESA) are combined with ionization or direct sample delivery to a mass spectrometer. Here, we describe three types of off-line direct sample extraction methods and their combination with multiple reaction monitoring (MRM) profiling to survey lipids present on the surface of beef and chicken meat as proof-of-concept samples. A collection of 679 MRMs selected from over 3200 MRMs related to lipids was profiled using a conventional capillary binary pump, autosampler and a triple quadrupole mass spectrometer system. The surface extraction experiments were performed manually by simply dispensing solvent onto the surface of the samples and recovering it immediately (liquid surface extraction - LSE), or by using solvent loaded into a large orifice tip to contact the sample for 5 seconds without dispensing (solvent "touch" extraction - STE). The third approach, surface vaporization extraction (SVE), was based on extracting vapors from the surface of the sample created using the tip of a wood-burning tool, collecting the vapors in a microtube, and diluting them for flow injection. LSE was used to evaluate the effect of different solvent compositions on the number of MRMs detected. Solvent acidification was also evaluated. Compared to the Bligh & Dyer extraction method using homogenized beef samples, LSE provided a consistently lower number of MRMs detected and the most informative solvent for surface extraction was pure acetonitrile. Since meat samples' surfaces are not completely flat and also present natural irregularities, the solvent volume recovered was variable. Therefore, we turned to STE to evaluate whether the lipid composition of beef brown spots was different from the red regions and to probe changes in composition due to one freeze-thaw cycle. Also, the reproducibility of STE between three users was evaluated. The third surface extraction approach, SVE, was applied to study the lipid profiles of vapors collected from raw and cooked meat. Overall, the three surface methods were able to provide informative discrimination for the different aspects assayed.