Search Results (3,410)

Excessive chemical fertilization in maize production has reduced fertilizer-use efficiency and increased pressure on soil quality, whereas reducing fertilizer input without yield loss remains challenging. This challenge has shifted attention toward strategies that improve crop nutrient acquisition and utilization under lower fertilizer supply. Harpin protein-based enzyme complexes may provide a regulatory approach, but their field performance under reduced fertilization remains unclear. A two-year field experiment was conducted from 2023 to 2024 using two maize cultivars, Heyu236 and Fuyuan2. In 2023, the harpin protein-based enzyme complex was applied at 200-fold and 300-fold dilutions under conventional fertilization to identify effective spraying concentrations. In 2024, the same two concentrations were evaluated under conventional fertilization and 15%, 30%, and 45% fertilizer reductions. In the 2023 concentration screening trial under conventional fertilization, the enzyme complex increased kernels per ear by 5.6–9.7% and tended to increase the yield by 0.4–17.2% (not significant). In 2024, under reduced fertilization, enzyme application combined with 30% fertilizer reduction produced a stable yield response. In particular, the 300-fold dilution combined with 30% fertilizer reduction increased kernels per ear by 18.1% and 13.2% and grain yield by 16.9% and 9.5% in Fuyuan2 and Heyu 236, respectively. Soil analyses showed that the enzyme treatment mainly improved nutrient availability, as reflected by higher available P, available K, alkali-hydrolyzable N, organic matter, and available Cu, Zn, Fe, and Mn in the soil. These findings suggest that the harpin protein-based enzyme complex helped maintain maize yield under moderate fertilizer reduction by improving kernel formation and soil nutrient availability. Among the tested treatments, foliar application at 300-fold dilution combined with 30% fertilizer reduction showed the greatest potential for reducing fertilizer input while sustaining maize productivity. Full article

Alpine grasslands and alpine deserts represent two major ecosystems on the Tibetan Plateau. However, whether the two ecosystems differ in soil microbial community diversity and co-occurrence network structure remains poorly understood. This study assessed the composition and diversity of soil bacterial communities across alpine grasslands and alpine deserts on the Tibetan Plateau via 16S high-throughput sequencing, analysis of variance(ANOVA), mantel test, and other methods. Our results revealed that soil alkaline-hydrolyzable nitrogen (SAN), soil total nitrogen (STN), soil total phosphorus (STP), soil available phosphorus (SAP), and soil organic carbon (SOC) were significantly higher in grassland than in desert (p < 0.05). The microbial community composition and diversity differed significantly between alpine grasslands and alpine deserts. Analysis of microbial co-occurrence networks revealed that grassland systems possessed significantly more nodes, edges, and a higher average degree than desert systems, along with greater network robustness—indicating a more complex and stable microbial community structure. Correlation analysis further revealed that SOC and STN were positively correlated with microbial diversity, while electrical conductivity (EC), SOC, STN, and SAN showed positive associations with microbial community composition. In conclusion, alpine grasslands harbor greater soil microbial diversity and more stable microbial co-occurrence networks than alpine deserts, suggesting that alpine grasslands may hold greater ecological value than alpine deserts in maintaining soil biodiversity and ecosystem functioning. This study not only elucidates the distribution patterns and diversity of soil microbial communities across Tibetan grasslands, but also offers critical insights into the mechanisms governing ecosystem functioning, thereby informing ecological conservation and sustainable management strategies on the plateau. Full article

Biological soil crusts (BSCs) play key roles in arid, semi-arid regions and ecological marginal habitats. This study focused on four types of sand-fixing plantations established in 1990 in alpine sandy land (Salix psammophila, SL; Caragana korshinskii, NT; Salix cheilophila, WL; Populus simonii, XYY). Soil samples were collected from bare sand, algae crusts, and moss crusts. Soil particle size distribution, physicochemical properties, and enzyme activity were determined. Then bacterial communities were analyzed using high-throughput (Illumina) sequencing and the correlations among these three factors were examined. The results showed that: (1) From bare sand to algae and moss crusts, the content of fine particles (clay + silt) gradually increased. (2) Soil water content (SWC), nutrients and enzyme activities increased progressively. (3) In the study area, the dominant bacterial phyla of BSCs included Pseudomonadota, Cyanobacteria, Actinobacteriota and Vibrionota. Principal Coordinates Analysis (PCoA) and Analysis of Similarities (ANOSIM) results showed that BSCs drive the differentiation of bacterial communities during succession, while forest stands influence their spatial distribution. (4) Spearman’s correlation and redundancy analysis (RDA) showed that available phosphorus (AP), alkaline hydrolyzable nitrogen (AN), soil organic matter (SOM), catalase (CAT), pH, soil water content (SWC), and alkaline phosphatase (ALP) are key physicochemical factors shaping the bacterial community structure of BSCs. Mantel’s test confirmed that these variables mediated BSCs’ bacterial community structure. This study elucidates the mechanisms underlying ecological restoration via BSCs and provides a theoretical basis for future restoration efforts in alpine sandy land. Full article

The Lysobacter capsici XL1 β-lytic protease (Blp) is a bacteriolytic enzyme that hydrolyzes peptide bonds in the interpeptide bridge of the peptidoglycan of Gram-positive bacteria, including antibiotic-resistant strains of pathogenic bacteria. The Blp has been extensively characterized. The only unexplored aspect is the mechanism by which this enzyme recognizes target cells. In this work, we demonstrated for the first time that the Blp structure contained a C-terminal subdomain that can be responsible for this interaction. Molecular modeling suggested a hydrophobic nature of the interaction between the Blp and peptidoglycan. Model mutant forms of the Blp, which have fewer hydrophobic areas in the C-terminal subdomain, also had fewer sites for potential interaction with the ligand. Wet lab experiments showed that these mutant Blp forms exhibited poorer binding to peptidoglycan and living Staphylococcus aureus 209P cells, resulting in decreased bacteriolytic and proteolytic activity. Amino acid residues N136 and Y160 in the C-terminal subdomain were identified and can be important for the interaction of the enzyme with target cells. Further research into the mechanism of target cell recognition by bacterial bacteriolytic proteases will enable the use of this knowledge to expand the specificity of action of these enzymes, including as antimicrobial agents for medical applications. Full article

Staphylococcus aureus, including methicillin- and vancomycin-resistant variants (MRSA, VRSA), causes infections that are increasingly difficult to treat with conventional antibiotics. One of the approaches to developing new therapeutics to treat staphylococcal infections is the use of bacteriophages specific to these bacteria or the lytic enzymes of such bacteriophages, which are capable of hydrolyzing the cell walls of these bacteria. Phage-encoded endolysins offer an alternative promising class of antimicrobial agents. In this study, LysSA120, a 250-amino-acid endolysin encoded by the S. aureus podophage vB_SauP_120, was cloned, expressed in Escherichia coli, and characterized. The domain organization and tertiary structure of LysSA120 were predicted. Recombinant LysSA120 hydrolyzed cell walls were obtained from S. aureus, S. epidermidis, S. haemolyticus, S. warneri, S. auricularis and S. saprophyticus. It was shown that treatment of S. aureus planktonic cells with endolysin LysSA120 led to reduced viability. Furthermore, LysSA120 could hydrolyze mature biofilm formed by VRSA. The lytic spectrum and antibiofilm activity of LysSA120 warrant its further evaluation as an enzybiotic against drug-resistant staphylococcal infections. Full article

This study aimed to identify novel umami peptides from both natural and enzymatically hydrolyzed peptides from Jinhua ham, and to characterize their properties. Following LC–MS identification, known flavor sequences were annotated using a curated flavor-peptide database containing 2617 known flavor peptides, and potential novel umami peptides were screened through an integrated approach combining multiple machine learning models and LibDock molecular docking. From over 2000 identified peptides, this integrated virtual screening pipeline precisely yielded 10 candidate umami peptides, which were confirmed to possess distinct umami characteristics by sensory evaluation and electronic tongue analysis. These peptides had umami intensities ranging from 2.87 ± 1.38 to 3.90 ± 1.56 and significantly lower taste thresholds (0.1109–0.2634 mg/mL) than that of monosodium glutamate (MSG, 0.3 mg/mL). Subsequent CDOCKER analysis demonstrated significantly stronger binding affinity and stability of these peptides to the T1R1/T1R3 receptor compared with MSG, with -CDOCKER ENERGY values of 78.45–94.95 and -CDOCKER INTERACTION ENERGY values of 56.67–86.71, both significantly higher than those of MSG (22.27 and 46.58, respectively). Hydrogen bonds were identified as the dominant binding force, accounting for over 66% of total interactions, and HIS145 and ARG247 were confirmed as the key residues maintaining the stability of the peptide-receptor complex. Overall, these findings provide mechanistic insight into the umami properties of Jinhua ham peptides and support their potential application in food processing. Full article

In this study, the formation of Maillard reaction products (MRPs), namely acrylamide (AA) and fluorescent advanced glycation end products (f-AGEs), was evaluated in four quinoa and four cañihua flours subjected to heating at 185 °C. The influence of endogenous phenolic compounds and the addition of tara hydrolyzed gallotannins on MRPs formation was investigated. Varieties with higher quercetin and rutin contents showed lower AA and f-AGEs formation. AA formation kinetics differed between species, increasing with heating time in quinoa, whilst decreasing after 20 min in cañihua. Maximum AA levels ranged from 18.6 to 87.0 μg/kg, remaining below the EU benchmark value for non-wheat-based bread (300 μg/kg). Compared with the Asn–Glc control system, flour systems reduced AA formation by approximately 18.7 to 60.3%, while tara hydrolyzed extract further enhanced inhibition, reaching reductions above 72.7 to 96.2%. Similar trends were observed for f-AGEs, with mitigation levels up to 54.1 to 77.4%. Cañihua varieties showed higher AA inhibition capacity than quinoa, likely associated with differences in phenolic composition and antioxidant capacity. These findings demonstrate the potential of Andean pseudocereals and tara-derived polyphenols as natural strategies to mitigate thermally induced contaminants in processed foods. Full article

In this study, 20% ethanol elution fraction(PC-20), 40% ethanol elution fraction(PC-40), 60% ethanol elution fraction(PC-60), and 80% ethanol elution fraction (PC-80)of Penthorum chinense polyphenols were obtained using AB-8 macroporous resin . Their in vitro bioactivities were compared to explore potential applications. A comprehensive phytochemical analysis identified 85 compounds, including 16 phenolic acids, 36 flavonoids, 24 hydrolyzed tannins, 7 anthocyanins, and 2 others. The results showed clear ethanol concentration-dependent variations in both compound composition and bioactivity. PC-20 had the highest levels of total polyphenols (418.45 mg/g), proanthocyanidins (84.95 mg/g), and tannins (10.61 mg/g), and also showed the best antioxidant capacity. PC-40 contained the most flavonoids (227.55 mg/g). PC-60 gave the strongest α-glucosidase inhibition (IC₅₀ = 0.79 µg/mL), while PC-20 was most effective against pancreatic lipase (IC₅₀ = 101.06 µg/mL) and also significantly activated the enzymes ADH and ALDH. Overall, PC-20 appears more suitable for applications aimed at antioxidant, anti-obesity, or liver-protective effects, whereas PC-60 is more promising for blood glucose control. This work provides a practical basis for selecting different ethanol fractions of P. chinense polyphenols according to specific functional needs. Full article

Lignocellulosic biorefineries are limited by the high cost of cellulolytic enzymes. Consolidated bioprocessing (CBP), which integrates saccharification and fermentation in one step, offers a solution to this challenge. In this study, a cellulase-hyperproducing mutant of Talaromyces pinophilus, Y117, was generated from the parental strain TP117 via sequential ultraviolet irradiation and NTG (N-methyl-N′-nitro-N-nitrosoguanidine) mutagenesis. Enzymatic secretion and lignocellulose degradation capacities were evaluated, focusing on agricultural residues, particularly corncob. Y117’s performance was compared with TP117 and Trichoderma reesei Rut-C30 (TR30) under high-solids fermentation. Furthermore, the lactate dehydrogenase A (ldhA) gene from Rhizopus oryzae was heterologously expressed in Y117 to direct hydrolyzed sugars toward lactic acid (LA). Y117 exhibited significantly enhanced enzymatic secretion, achieving FPase activity of 8.9 IU/mL and a substrate utilization rate of 72.2% at 125 g/L corncob solids. Y117 outperformed TP117 and TR30 in cellulase, xylanase, and CMCase activities, as well as growth under high-solids fermentation conditions. In the LA fermentation process, Y117 produced 14.20 g/L LA, a notable improvement compared to TP117 (5.33 g/L) and TR30 (2.71 g/L). While LA productivity and yield currently remain below bacterial benchmarks, the unique CBP capability of Y117 provides a foundation for further metabolic engineering toward industrial viability. The engineered T. pinophilus Y117 demonstrates promising potential as a CBP platform for efficient straw-to-LA conversion, providing a sustainable approach for third-generation biobased materials production. Full article

Plant growth-promoting fungi (PGPF) have shown broad potential to improve soil conditions and enhance root growth and development. However, few studies have examined the effects of exogenous PGPF inoculation on the growth of the medicinal plant Saposhnikovia divaricata and the associated changes in the rhizosphere microbiome. In this study, Aspergillus neoalliaceus MR-86 exhibited phosphate solubilization, growth in nitrogen-free medium, potassium solubilization, IAA production, and siderophore production. PCR assays did not detect the aflatoxin biosynthesis-related genes aflR, aflS, and omtA in strain MR-86. Pot trials demonstrated that inoculation with MR-86 significantly increased the plant height and root dry weight of S. divaricata by 10.32% and 21.05%, respectively (p < 0.05). In the rhizosphere, soil pH decreased, whereas soil alkaline-hydrolyzable nitrogen and available phosphorus levels, as well as the activities of protease, urease, and cellulase, increased significantly. Illumina NovaSeq sequencing revealed that MR-86 inoculation altered the soil microbial community structure and specifically enriched several microbial taxa, including Talaromyces, Subulicystidium, and Aspergillus. Moreover, MR-86 inoculation did not alter the composition of dominant bacterial and fungal phyla, but significantly modified microbial interactions and the topology of microbial networks. Correlation analysis indicated that the specific microbial taxa Subulicystidium, Aspergillus, and Talaromyces were positively associated with soil nutrient indices, enzyme activities, and plant growth parameters. Functional prediction analysis indicated that MR-86 treatment was predicted to be enriched bacterial metabolic pathways, including flavone and flavonol biosynthesis and ether lipid metabolism, and was predicted to increase the relative abundance of functional fungal groups such as ectomycorrhizal and wood-decomposing fungi. In summary, A. neoalliaceus MR-86 may contribute to improved growth of S. divaricata by enhancing nutrient availability and transformation and by modulating the structure and function of the rhizosphere microbiome. Full article

Recycling cotton–PET textile blends using alkaline solutions has gained increasing attention, with studies showing promising treatment pathways with diverse process setups. However, these separation processes use various input materials and focus on a small number of treatment parameter values which render the comparison of results over a large parameter range difficult. This study presents the feasibility of recovering cotton or PET at fabric level from cotton–PET blends across a wide range of temperatures (from −30 °C to 95 °C) and alkaline concentrations (from 0 to 40% (w/w)). The focus of this study is centered on the share of separation and recoverable fiber mass after hydrolyzing one component using alkaline hydrolysis or alkaline pre-treatment followed by enzymatic hydrolysis. A comparison of purity and material loss of the recovered polymers for all parameter sets is given. Experiments were performed on two distinct textiles while process parameters were selected in a straightforward manner, excluding catalysts, co-solvents and defibration. The results map temperature and alkaline concentration areas where these cotton–PET separation processes are feasible regarding recoverable fiber mass. Based on these results, separation efficiency could be optimized to design economic and environmentally friendlier process conditions. Full article

Arbuscular mycorrhizal fungi (AMF) can improve plant performance, but how they coordinately influence root metabolism and associated bacterial communities in sweet potato remains unclear. Here, a pot experiment was conducted to investigate the effects of Glomus intraradices inoculation on sweet potato seedlings by integrating analyses of rhizosphere soil properties, plant growth and nutrient uptake, root metabolomics, and rhizosphere and endophytic bacterial communities using 16S rRNA gene sequencing with FAPROTAX-based functional prediction. AMF inoculation significantly increased whole-plant fresh and dry biomass, potassium concentration and accumulation, and the accumulation of starch and water-soluble carbohydrates, while no significant effects were observed on dry matter rate or plant nitrogen and phosphorus concentration. In the rhizosphere, AMF reduced soil electrical conductivity and increased organic matter content without significantly affecting pH, alkali-hydrolyzable nitrogen, available phosphorus, or available potassium. Root metabolomic profiling identified 289 differential metabolites, with enrichment of phenylpropanoid biosynthesis, glycerophospholipid metabolism, porphyrin metabolism, and nucleotide metabolism, together with broad up-regulation of lipid-related metabolites. Bacterial communities showed strong compartment specificity, with the root endosphere displaying lower alpha diversity than the rhizosphere. Higher rhizosphere bacterial Shannon diversity was observed in the AMF treatment, together with compartment-dependent shifts in bacterial community composition; enrichment of endophytic taxa such as Devosia and Niastella was detected following AMF inoculation. Functional prediction further suggested niche differentiation between rhizosphere and endophytic bacteria, together with AMF-associated shifts in carbon- and nitrogen-related functions. Overall, these results suggest that G. intraradices inoculation is associated with enhanced sweet potato growth and enhanced potassium and carbohydrate accumulation in association with coordinated changes in rhizosphere conditions, root metabolism, and bacterial community assembly. Full article

Mycoplasmas are frequently recovered from the upper respiratory tract of birds of prey, yet many isolates remain taxonomically unresolved. In the present study, a collection of ten previously unclassified Mycoplasma strains, predominantly isolated from the trachea of the common buzzard (Buteo buteo), was subjected to comprehensive phenotypic and genomic characterization. All strains grew well in modified Hayflick’s medium and formed colonies with the characteristic fried-egg appearance. None of the strains produced acid from glucose or hydrolyzed arginine or urea. Phylogenetic analyses based on 16S rRNA gene, 16S–23S intergenic spacer, and partial rpoB gene sequences placed the strains within the Mycoplasma synoviae cluster, in close proximity to five recently described Mycoplasma species associated with raptors such as eagles and kites. Matrix-assisted laser desorption ionization–time of flight (MALDI-ToF) mass spectrometry enabled the clear discrimination of the investigated strains from closely related taxa. Whole-genome comparisons, together with phylogenomic analyses, supported the assignment of these strains to a novel species within the genus Mycoplasma. The name Mycoplasma tracheobuteonis sp. nov. is proposed, corresponding to its preference for colonizing the upper respiratory tract of the common buzzard, with strain 48589B^T (=DSM 115882^T = NCTC 14927^T) designated as the type strain. Full article

This study evaluated the effects of crayfish shell meal (CSM) processed by drying, enzymatic hydrolysis, or fermentation on juvenile largemouth bass (Micropterus salmoides). A total of 320 fish (initial body weight, approximately 5.69 g) were distributed into 16 tanks, with 20 fish per tank and four replicates per treatment. Four isonitrogenous and isoenergetic diets were prepared: a fish meal-based control diet (FM) and three diets containing 4.5% dried CSM (DCSM), enzymatically hydrolyzed CSM (ECSM), or fermented CSM (FCSM), in which fish meal was reduced from 45.0% to 39.6%, and were fed for 8 weeks. Compared with the FM group, DCSM significantly reduced final body weight, weight gain rate, specific growth rate, and protein efficiency ratio, and increased feed conversion ratio (p < 0.05). ECSM generally showed intermediate responses, whereas FCSM did not differ significantly from FM in these growth and feed utilization indices (p > 0.05). DCSM also significantly increased serum aspartate aminotransferase and blood urea nitrogen levels and induced a pro-inflammatory intestinal response, as indicated by decreased il10 and increased il1b and tnfa expression (p < 0.05). Compared with DCSM, FCSM significantly improved these serum and inflammatory indices, increased intestinal trypsin, Na⁺/K⁺-ATPase and γ-glutamyl transferase activities (p < 0.05), and showed more favorable antioxidant and gut microbiota responses. Overall, fermentation was more effective than enzymatic hydrolysis in improving the feeding value of CSM for largemouth bass. These results suggest that FCSM is a promising alternative ingredient for aquafeeds and may contribute to the high-value utilization of crayfish processing by-products. Full article

The amphiphilic peptides formed by moderate enzymatic hydrolysis of proteins can self-assemble into various structures at different pH levels, resulting in differences in the encapsulation efficiency of hydrophobic substances. In this work, a new plant protein of edible dock protein (EDP) was moderately hydrolyzed by Bacillus licheniformis proteinase to prepare hydrolyzed edible dock protein (HEDP). The self-assembly behavior and interaction mechanism of HEDP with myricetin (Myr) at different pHs were explored. The results showed that the loading capacity of Myr by HEDP was 13.86% higher than that of EDP before enzymatic hydrolysis. Moreover, under pH 9.0, the zeta potential, particle size, and PDI of the Myr-HEDP were −34.77 mV, 119 nm, and 0.33, respectively. Meanwhile, the Myr at this pH had the highest encapsulation efficiency (94.55%) and loading capacity (24.8%). Transmission electron microscopy exhibited that the Myr-HEDP nanomicelles had an obvious core–shell structure. Spectroscopy experiments confirmed that there were varying intensities of hydrogen bonding and hydrophobic interactions between HEDP and Myr at different pHs, wherein the binding intensity was largest at pH 9.0. Additionally, the stability evaluation indicated that the UV, thermal, storage, and digestive stability of Myr within the Myr-HEDP nanomicelles at pH 9.0 were more stable than at other pH conditions. In summary, pH 9.0 was more conducive to the self-assembly of HEDP and Myr, forming stable composite nanomicelles. This study will provide an important input into designing more stable and efficacious EDP delivery systems. Full article