Search Results (31,489)

To identify chitinase genes from the genome of the mycoparasitic Cladosporium sp. strain SYC23, bioinformatical analyses and real-time quantitative PCR (RT-qPCR) were employed to screen mycoparasitism-associated genes at 12, 24, 48, and 72 h post-induction with Aecidium pourthiaea rust spores. A total of eight chitinase genes were identified from SYC23 via bioinformatics analysis and designated CaChi34, CaChi40, CaChi45, CaChi67, CaChi82, CaChi92, CaChi93, and CaChi286 based on sequence and phylogenetic analyses. Analysis of the chitinase protein sequence characteristics revealed molecular weights ranging from 33.86 to 286.03 kDa and theoretical isoelectric points from 4.48 to 7.7. All CaChi genes contained the conserved GH18 domain, and promoter analysis showed that each harbored MYB-binding sites and pathogen-responsive elements. Mycoparasitism-related sequence clustering analysis indicated that the chitinase sequences of SYC23 shared the closest phylogenetic relationship with those from Trichoderma sp. RT-qPCR results following rust spore induction showed that five CaChi genes reached their highest expression levels at 24 h post-induction, CaChi45 was most highly expressed at 72 h post-induction, CaChi93 was continuously upregulated, and CaChi82 was continuously downregulated throughout the induction period. His-tagged recombinant CaChi93 protein was purified from E. coli and characterized. The results demonstrate that the enzymatic activity of CaChi93 was 0.929 U/mg, with optimal reaction conditions at 65 °C and pH 7. Treatment of A. pourthiaea rust spores with the recombinant CaChi93 chitinase confirmed that CaChi93 could effectively dissolve rust spore walls. In conclusion, this study confirms that the mycoparasitic Cladosporium sp. strain SYC23 can secrete chitinase to degrade the rust spore wall and induce spore death, thereby providing novel gene resources and a theoretical basis for the biological control of A. pourthiaea. Full article

Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by high metabolic activity, chronic endoplasmic reticulum stress, and persistent redox imbalance. Excessive immunoglobulin synthesis and adaptation to the hypoxic bone marrow microenvironment lead to sustained production of reactive oxygen species (ROS). Their excessive accumulation promotes genomic instability, disease progression, osteolytic bone disease, and resistance to therapy. Paradoxically, MM cells adapt to oxidative stress by activating antioxidant and metabolic defense mechanisms, including Nuclear factor erythroid 2-related factor 2 (NRF2)- and Heme Oxygenase 1 (HMOX1)-dependent pathways, metabolic reprogramming, and overexpression of ROS-scavenging enzymes such as peroxiredoxin 6 (PRDX6), allowing survival at the threshold of oxidative toxicity. Evidence indicates that biomarkers of oxidative stress—such as lipid and protein oxidation products, antioxidant enzyme activity, and the Oxidative Stress Score—correlate with disease stage, prognosis, and treatment response. Redox-modulating therapeutic strategies, including pharmacological ROS induction, inhibition of antioxidant defenses, and the use of natural pro-oxidant compounds, are emerging as promising adjuncts to standard MM therapies. Recent studies also highlight the gut microbiota as an indirect regulator of oxidative balance, immune modulation, and metabolic homeostasis in MM. This review summarizes current knowledge on oxidative stress in multiple myeloma, emphasizing its role in pathogenesis, drug resistance, biomarker development, and emerging therapeutic and supportive strategies. Full article

Jujube (Ziziphus jujuba Mill.) cultivation in arid regions of China faces severe soil constraints, including high alkalinity, low organic matter content, and poor water retention. Although soil amendments have demonstrated potential for improving soil quality, their combined effects on soil–plant–microbe interactions in desert agroecosystems remain poorly understood. This study conducted a three-year field experiment in a desert jujube orchard in southern Xinjiang, China, to evaluate six nitrogen fertilizer management strategies: urea alone (CK) or combined with biochar (NB), bentonite (NP), graphene (NS), biochar plus bentonite (NBP), or microbial inoculants (NW). Soil physicochemical properties, enzyme activities, bacterial community structure, and jujube yield were analyzed. Structural equation modeling (SEM) was employed to elucidate the pathways linking soil amendments to crop productivity. Results showed that NBP was the most effective in improving soil physical structure, significantly reducing bulk density and enhancing water retention capacity compared to the control. The NBP treatment also enhanced soil organic matter (30% increase), available phosphorus (119% increase), and urease activity (44% increase), resulting in the highest jujube yield (7.14 kg per tree). Bacterial community analysis revealed that NBP significantly increased Shannon diversity and enriched Actinobacteriota and Proteobacteria. SEM analysis indicated that urease activity served as a significant mechanistic pathway linking soil organic matter improvements to enhanced crop productivity. These findings demonstrate that combined application of biochar and bentonite with nitrogen fertilizer represents an effective strategy for improving soil quality, enhancing microbial functionality, and increasing crop yield in desert jujube orchards, providing a practical and synergistic amendment combination for sustainable soil management and productivity enhancement in arid agroecosystems. Full article

Immunosuppression is associated with impaired immune responses and increased susceptibility to disease, highlighting the need for safe and effective immunomodulatory strategies. Oligosaccharides derived from natural sources have attracted growing interest due to their bioactivity and regulatory effects on host immunity. The present study was designed to evaluate the immune-enhancing potential of Periplaneta americana oligosaccharides (PAOSs) and to explore their association with SCFA-producing gut microbiota and metabolic regulation in an immunosuppressed mouse model. PAOS administration significantly increased serum immunoglobulin levels (IgG and IgM), promoted the secretion of immunoregulatory cytokines (IFN-γ, IL-2, TNF-α, IL-10, and IL-4), and elevated the proportion of CD4⁺ T cells in the spleen. In addition, PAOSs alleviated oxidative stress by reducing malondialdehyde accumulation while promoting the activity of key antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase. Metabolomic analysis revealed that PAOSs altered host metabolic profiles, particularly enhancing pyrimidine metabolism. Furthermore, PAOSs markedly enriched short-chain fatty acid (SCFA)-producing bacteria, and elevated colonic short-chain fatty acid levels. These changes were closely associated with the observed improvement in immune function. Collectively, this study demonstrated that PAOSs exerted immunomodulatory effects through coordinated regulation of SCFA-producing gut microbiota and host metabolism, elucidating the mechanisms underlying the bioactivity of insect-derived oligosaccharides. Full article

Raspberry (Rubus idaeus L.) fruits have been widely used due to their abundance of diverse polyphenolic compounds, whereas research on the chemical composition and bioactivity of their stems and leaves remains limited. In this study, the ethyl acetate extract of raspberry stems and leaves was evaluated for inhibitory activity against α-glucosidase and α-amylase. Guided by affinity ultrafiltration–mass spectrometry, 16 potential active components were further isolated and characterized. Among these, 13 compounds exhibited binding affinity for α-amylase, while 5 compounds showed binding affinity for α-glucosidase. Quercetin-3-O-β-D-glucoside-7-O-β-D-gentiobioside was isolated from raspberry stems and leaves for the first time. Procyanidin C₃ and quercetin exhibited significant inhibitory effects on the two enzymes. Molecular docking studies hinted at the interactions between these compounds and the key active sites of the two enzymes. These findings suggest that phenolic compounds in raspberry stems and leaves may possess potential as α-glucosidase and α-amylase inhibitors, providing a scientific basis for further research on their application as functional components for blood glucose control. Full article

Plantain (Musa paradisiaca) peel is an agro-industrial waste product with remarkable functional potential, attributed to its composition of bioactive compounds with antioxidant and antimicrobial properties. Given this scenario, this scoping review aimed to map and synthesize the scientific evidence regarding the nutritional composition and potential functionalities of plantain peel. A scoping review approach was used, and data were reported using the PRISMA-ScR checklist. The studies evaluating the use of plantain peel were included without restrictions on language or publication date. The following databases were searched: Embase, MEDLINE (via PubMed), Scopus, and Web of Science. Additional searches were conducted through Google Scholar. The protocol has been registered prospectively on the Open Science Framework. This review’s findings included 53 studies. All of them presented methodological limitations that hindered further analysis and the generation of robust evidence. This analysis detailed the chemical composition of the peel, showing that it varies with ripeness stage and processing and is an excellent source of fiber and minerals. Several technological applications are explored, including the use of peel in the production of functional foods, the development of nanoparticles with antimicrobial activity, and its use as a substrate for the biosynthesis of industrial enzymes and citric acid. This review also addresses the possible health benefits that have already been studied in animal and in vitro models. Plantain peel is a promising agro-industrial by-product with high fiber, starch, and bioactive compound content and functional properties. Despite advances, challenges in sensory acceptance and process standardization limit industrial application. A key research gap remains in the systematic evaluation of antinutrient reduction (e.g., oxalates, phytates) and pesticide residue levels during the processing of plantain peel, a mandatory step before its widespread application in the food industry (e.g., flours and food additives). Further research on optimization and bioactive mechanisms is essential to enable its large-scale use and strengthen its role in the circular bioeconomy and human health. Full article

The enzymatic valorization of agarose, a major polysaccharide in red algae, is critical for its application in the food, pharmaceutical, and biotechnology industries. In this study, a gene encoding a thermostable α-neoagarobiose hydrolase, aga2457, was cloned from an epiphytic bacterium associated with Indonesian macroalgae. Unlike typical mesophilic GH117 enzymes, recombinant Aga2457 displayed a higher optimal temperature at 50 °C and retained 55% activity after 12 days of incubation at 50 °C. The enzyme specifically hydrolyzes neoagarobiose into D-galactose and 3,6-anhydro-L-galactose, thereby facilitating the complete depolymerization of agarose. Combined molecular dynamics (MD) simulations and site-directed mutagenesis revealed that residues P253, N256, and Q285 are pivotal for substrate recognition and active site stability. These findings highlight Aga2457 as a robust biocatalyst for industrial agar processing and provide structural insights for the rational design of thermostable agarolytic enzymes. Full article

Early intervention is pivotal for mitigating the progression of Alzheimer’s disease (AD). This study presents an electrochemical immunosensor targeting synaptic vesicle glycoprotein 2A (SV2A) to facilitate early AD diagnosis. A sensing interface was engineered using a nanocomposite of graphene oxide (GO) and 3-carboxyl polypyrrole (3-COOH-PPy). Leveraging the synergistic effects between the large specific surface area of GO and the superior conductivity of 3-COOH-PPy, the composite established an efficient electron transport network. This architecture provided abundant active sites for capture antibody immobilization while significantly enhancing interfacial electron transfer kinetics. Coupling this interface with an enzyme-mediated signal amplification strategy based on the horseradish peroxidase (HRP)-catalyzed TMB/H₂O₂ system, the immunosensor achieved high sensitivity. It exhibited a wide linear range of 2 ng/mL to 16 μg/mL with a low limit of detection (LOD) of 0.15 ng/mL. Furthermore, successful detection in C57 mouse serum samples validated the method’s reliability and potential for clinical application. In conclusion, this immunosensor offers a sensitive and robust platform for the early diagnosis of AD. Full article

Complex I (NADH:quinone oxidoreductase, CI) is central to cellular aerobic energy metabolism. The L-shaped structure of CI is unique, where the hydrophilic arm is responsible for the electron transfer function and the membrane arm operates proton pumping. These two functional sites are spatially far apart yet functionally connected. This basic core subunit architecture is highly conserved from bacterial to mammalian CI. Here, to gain detailed mechanistic insight into the role of the membrane subunit ND2 in the coupling mechanism, we mutated several highly conserved residues in the middle of the membrane axis of NuoN, the E. coli CI homolog of ND2. To more precisely investigate the consequences of mutational effects on highly conserved residues, we purified each mutant CI and compared the mutational effects on electron transfer and proton pumping activity using our instant membrane reconstitution method with E. coli double knockout (DKO) membrane vesicles lacking both CI and alternative NADH dehydrogenase (NDH-2). Thre results were corroborated by conventional proteoliposome reconstitution experiments. We found that Lys247 and Lys395 are absolutely essential for both electron transfer and proton pumping activities, while about 50% reduction of NADH oxidase activity but no reduction in proton pumping activity was observed in Lys217, and no significant decrease was detected in Glu133. Furthermore, unexpectedly, we were able to purify an NuoN knockout (ΔNuoN) mutant, which contained stoichiometric peripheral subunits NuoB, NuoCD, NuoE, NuoF, NuoG, and NuoI; and a substoichiometric amount of NuoH and a reduced amount of quinone. However, surprisingly, this isolated ΔNuoN CI showed CI activities (~30% of the WT) after being reconstituted into DKO membranes but not into proteoliposomes. Later, we confirmed by blue native PAGE that the wild-type CI was partially formed from ΔNuoN CI by recruiting its missing membrane subunits that existed in DKO membranes. Our data strongly suggest that ND2/NuoN plays an essential role in the coupling mechanism in CI. CI is the entry respiratory chain enzyme and is central to cellular energy metabolism. Two highly conserved lysine residues in the center of the antiporter-like membrane subunit ND2 are essential for the coupling mechanism between electron transfer and proton translocation. Full article

Charge transport underpins essential biological processes, including cellular respiration, photosynthesis, and enzymatic catalysis. Advances in molecular electronics have enabled single-molecule measurements that unequivocally establish redox-active proteins as efficient electron conductors, with their metal cofactors serving as intrinsic redox relays. By contrast, ubiquitous non-redox proteins lacking such redox centers have long been considered poor conductors. However, recent research has challenged this view, demonstrating that efficient charge transport in non-redox proteins can be mediated through polypeptide backbones, aromatic side-chain arrays, and hydrogen bond networks. This review surveys progress in understanding the single-molecule conductance of non-redox proteins. Firstly, we elucidate the fundamental transport mechanisms, highlighting the interplay between coherent tunneling and thermally activated hopping. We then provide an overview of state-of-the-art experimental techniques for single-molecule characterization. Through analysis of diverse systems spanning short peptides to large enzymes, we illustrate how aromatic amino acid networks and dynamic conformational fluctuations govern conductance, enabling emerging applications in label-free biosensing and single-molecule protein/DNA sequencing. Finally, we discuss persistent challenges and outline future opportunities for integrating protein-based conductors into bioelectronic devices. This review aims to stimulate further research and pave the way for novel applications harnessing protein conductance. Full article

This study aims to investigate the effects of low-energy diets (LE) supplemented with Lactobacillus reuteri postbiotics (HSY) on growth performance and intestinal health of broiler chickens. A total of 2400 one-day-old Ross 308 broiler chicks with an average initial body weight of 46.10 ± 0.04 g were randomly assigned to a 2 × 2 factorial arrangement of treatments with 12 pens and 50 broiler chickens/pen for 39 days. Treatments were (1) CTR (basal diet), (2) LE (CTR-70 kcal ME/kg), (3) HSY (CTR + 0.5 kg/t HSY), and (4) LEHSY (LE + 0.5 kg/t HSY). LE increased the feed conversion ratio (FCR) of broilers (p = 0.03) without altering ADG, ADFI, and final BW. Supplementation with HSY significantly reduced the FCR of broilers (p = 0.001). HSY upregulated the activities of amylase and trypsin in jejunal digesta (p < 0.01). Furthermore, LE upregulated the expression of intestinal barrier-related genes such as Mucin-2, Claudin-1 and Occludin, and HSY upregulated the expression of Claudin-1 (p < 0.05). LE upregulated the expression of nutrient transport carriers such as SGLT1 and TRPV6 (p < 0.01), and HSY upregulated the expression of TRPV6 (p < 0.01). LE upregulated the expression of immune-related genes such as MHC-II (p = 0.002), and HSY upregulated the expression of IFN-γ, IL-10, and TGF-β (p < 0.05). LE and HSY both downregulated the expression of intestinal lipid metabolism-related genes like ACC, while upregulating the expression of FABP4 (p < 0.05). 16S rRNA sequencing showed that the HSY increased the Chao1 index of the jejunal microbiota and enriched beneficial bacteria such as Lactobacillus salivarius and Lactobacillus avium. LE and HSY both increased the concentrations of propionic and butyrate (p < 0.05). In summary, HSY can improve gut health and mitigate the negative impact of low-energy treatment on broiler growth performance by increasing the content of endogenous enzymes in the jejunum, improving gut microbiota structure, and increasing the content of short-chain fatty acids in the jejunum. Full article

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by irreversible fibrosis. Aberrant cell differentiation plays a crucial role in the development of IPF. Although recent studies have suggested that mitochondrial dysfunction may play a role in IPF, its direct impact on fibrosis remains unclear. This study aimed to clarify the role of mitochondria in lung cell differentiation and pulmonary fibrosis development by employing mito-mice ND6^M, in which the activity of respiratory chain complex I is decreased due to a mitochondrial DNA mutation (G13997A). Pulmonary fibrosis was induced by administering bleomycin (BLM) to both wild-type and mito-mice ND6^M. Bone marrow-derived macrophages and primary lung fibroblasts, generated from both types of mice, were analyzed to evaluate M1/M2 polarization and myofibroblast differentiation, respectively. Compared to wild-type mice, mito-mice ND6^M exhibited more severe fibrosis and lower survival rates following BLM inoculation. Lactate production in the lungs after BLM administration was significantly higher in mito-mice ND6^M than in wild-type mice. TGF-β1-treated fibroblasts from mito-mice ND6^M exhibited increased α-smooth muscle actin expression. While type I collagen expression was not different between these mice, TGF-β1-induced expression of phosphoserine phosphatase and serine hydroxymethyltransferase2, two of the enzymes involved in the serine–glycine pathway, was significantly higher in mito-mice ND6^M than in wild-type mice. On the other hand, mitochondrial dysfunction had a small effect on pulmonary inflammation and on M1/M2 macrophage polarization. In conclusion, mitochondrial dysfunction promotes TGF-β1-induced myofibroblast differentiation and BLM-induced pulmonary fibrosis. Mitochondria-dependent metabolic reprogramming may therefore represent a promising therapeutic target in IPF. Full article

Temperature and nitrogen fertilizer are key environmental factors that significantly affect rice growth and grain quality. There remains a lack of systematic research on the effects of temperature and nitrogen fertilizer on carbon–nitrogen metabolism during grain-filling, and consequently on the taste quality of rice varieties with different taste characteristics. To bridge this gap, pot experiments were conducted under different temperature and nitrogen fertilizer conditions to investigate the changes in carbon and nitrogen metabolism and the quality of different high-quality and stable-taste rice varieties during the grain filling stage. Our research results indicate that high-temperature conditions inhibit both carbon and nitrogen metabolism; however, the variations differ among rice varieties with differing taste stability. Under both normal and high nitrogen levels, compared to Akita Komachi (AK), a variety with poor taste stability, Jikedao 606 (J 606), a variety with strong taste stability, maintained a certain photosynthetic capacity under high-temperature conditions, with smaller decreases in net photosynthetic rate and soil–plant analysis development values, declining by 4.30–5.59% and 4.30–5.59% respectively. The decline in the activities of nitrate reductase, glutamine synthetase, and glutamate synthase in nitrogen metabolism was relatively small; in comparison, the decrease in the activities of ADP-glucose pyrophosphorylase, granule-bound starch synthase, starch branching enzyme, and starch debranching enzyme in carbon metabolism was comparatively minor. The content of amylose and amylopectin in the grains was maintained, improving the milled rice rate and head rice rate, thereby ensuring strong stability of excellent sensory quality. Under both high-temperature and high-nitrogen conditions, the yields of the two rice varieties were maintained. In summary, variations exist in carbon and nitrogen metabolism among different rice varieties with stable excellent taste under varying temperature and nitrogen fertilizer conditions. These metabolic differences affect starch synthesis in the endosperm, ultimately influencing the stability of rice sensory quality. This study provides a theoretical basis for nitrogen fertilizer application under high-temperature conditions and the cultivation of rice varieties with excellent taste stability. Full article

The physicochemical and bioactive properties of polysaccharides from blue honeysuckle (Lonicera caerulea L.) berries were comprehensively investigated. Fourier transform infrared spectroscopy confirmed that both samples were acid heteropolysaccharides. High-performance liquid chromatography detailed a monosaccharide profile of arabinose, galacturonic acid, rhamnose, galactose, and glucose in specific molar ratios. High-performance gel permeation chromatography further revealed variations in molecular weight and distribution among the samples. Functionally, the polysaccharides exhibited significant in vitro antioxidant capacity. For the first time, the polysaccharides are shown to inhibit pancreatic lipase, in addition to α-amylase and α-glucosidase, demonstrating potent inhibitory activity with low IC₅₀ values (2.80 ± 0.12 mg/mL). This bioactivity, particularly toward lipase, was correlated with structural properties such as monosaccharide profile and molecular weight. These results highlight the potential of these polysaccharides as functional food ingredients for managing hyperglycemia and obesity and provide novel insights into their structure–activity relationships. Full article

Synthetic dyes discharged from the textile and dyeing industry present a significant environmental and health hazard due to their inherent toxicity, environmental persistence, and potential carcinogenicity. Microbial degradation has garnered significant interest as a cost-effective and eco-friendly strategy for dye wastewater treatment in recent years. The study systematically evaluated the decolorization performance, degradation pathways, and detoxification effects of three bacterial strains, including Rhodopseudomonas palustris gh32, Bacillus cereus HL7, and Bacillus safensis X64, on the dye indigo carmine (IC) and three azo dyes: reactive black 5 (RB5), direct black G (DBG), and direct blue 15 (DB15). The degradation mechanisms were elucidated through UV-Vis spectroscopy, UPLC-Orbitrap-HRMS analysis, and enzyme activity assays. Molecular docking simulations were employed to investigate the interactions between key redox enzymes (such as laccase, tyrosinase, and azoreductase) and the dye molecules. The results demonstrated that the strain-specific enzymatic systems effectively disrupted the dye structures. Significant detoxification effects were further confirmed through a series of bio toxicity assays involving Escherichia coli, Bacillus subtilis, plant seeds, and erythrocytes. The addition of Fe³⁺, sodium citrate, or yeast extract significantly enhanced both the decolorization efficiency and enzyme activity. This study provides an in-depth understanding of the bacterial dye degradation process at the mechanistic level, highlighting the potential of customized bacterial systems for eco-friendly dye wastewater treatment. It offers theoretical support for elucidating the mechanisms of bacterial dye degradation and advancing bioremediation technologies. Full article