Search Results (192)

Background/Objectives: Antimicrobial resistance (AMR) contributes to millions of deaths globally each year, creating an urgent need for new therapeutic agents. Antimicrobial peptides (AMPs) have emerged as promising candidates due to their potential to combat AMR pathogens. This study aimed to evaluate the antimicrobial activity of an AMP from a soil-derived bacterial isolate against Gram-negative bacteria. Method: Soil bacteria were isolated and screened for antimicrobial activity. The bioactive peptide was purified and determined its structure and antimicrobial efficacy. Genomic analysis was conducted to predict the biosynthetic gene clusters (BGCs) responsible for AMP production. Results: Genomic analysis identified the isolate as Paenibacillus sp. Na14, which exhibited low genomic similarity (61.0%) to other known Paenibacillus species, suggesting it may represent a novel species. The AMP from the Na14 strain exhibited heat stability up to 90 °C for 3 h and retained its activity across a broad pH range from 3 to 11. Structural analysis revealed that the Na14 peptide consisted of 14 amino acid residues, adopting an α-helical structure. This peptide exhibited bactericidal activity at concentrations of 2–4 µg/mL within 6–12 h, and its killing rate was concentration-dependent. The peptide was found to disrupt the bacterial membranes. The Na14 peptide shared 64.29% sequence similarity with brevibacillin 2V, an AMP from Brevibacillus sp., which also belongs to the Paenibacillaceae family. Genomic annotation identified BGCs associated with secondary metabolism, with a particular focus on non-ribosomal peptide synthetase (NRPS) gene clusters. Structural modeling of the predicted NRPS enzymes showed high similarity to known NRPS modules in Brevibacillus species. These genomic findings provide evidence supporting the similarity between the Na14 peptide and brevibacillin 2V. Conclusions: This study highlights the discovery of a novel AMP with potent activity against Gram-negative pathogens and provides new insight into conserved AMP biosynthetic enzymes within the Paenibacillaceae family. Full article

This study reports the development of a sustainable biocatalyst system for free fatty acid (FFA) production from cocoa bean shell (CBS) oil using Burkholderia cepacia lipase (BCL). CBS was explored as both a support material and a reaction substrate. Six immobilized systems were prepared using organic (CBS), inorganic (silica), and hybrid (CBS–silica) supports via physical adsorption or covalent binding. Among them, the covalently immobilized enzyme on CBS (ORG-CB) showed the most balanced performance, achieving a catalytic efficiency (Ke) of 0.063 mM⁻¹·min⁻¹ (18.6% of the free enzyme), broad pH–temperature tolerance, and over 50% activity retention after eight reuse cycles. Thermodynamic analysis confirmed enhanced thermal resistance for ORG-CB (Ed = 32.3 kJ mol⁻¹; ΔH‡ = 29.7 kJ mol⁻¹), while kinetic evaluation revealed that its thermal deactivation occurred faster than for the free enzyme under prolonged heating. In application trials, ORG-CB reached 60.1% FFA conversion from CBS oil, outperforming the free enzyme (49.9%). These findings validate CBS as a dual-function material for enzyme immobilization and valorization of agro-industrial waste. The results also reinforce the impact of immobilization chemistry and support composition on the operational and thermal performance of biocatalysts, contributing to the advancement of green chemistry strategies in enzyme-based processing. Full article

Dryopteris fragrans (L.) Schott synthesizes volatile sesquiterpenes through the mevalonate pathway (MVA), in which 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) serves as the key rate-limiting enzyme. Although HMGR plays a crucial role in terpenoid biosynthesis, its functional characteristics in D. fragrans and its involvement in stress responses remain unclear. This study identified three HMGR genes (DfHMGR1/2/3) from the transcriptome data of D. fragrans. Bioinformatics analysis revealed that the encoded proteins are localized to the endoplasmic reticulum and share high sequence similarity with fern homologs. Under abiotic stress conditions, DfHMGRs exhibited differential expression patterns, with marked upregulation under salt and drought stress. To validate the functions of these genes, we generated transgenic Nicotiana tabacum L. plants overexpressing DfHMGRs. Compared with wild-type controls, the transgenic lines showed enhanced tolerance to drought and heat stress. Promoter analysis identified functional regulatory regions controlling DfHMGR expression, and co-expression network analysis predicted 21 potential transcriptional regulators. This study validates the function of D. fragrans HMGRs in a heterologous system and provides candidate genes for improving stress resistance in plants. Full article

Gamma-aminobutyric acid (GABA), a ubiquitous non-protein amino acid, plays a vital role in the response of plants to biotic and abiotic stresses. This review summarizes the underlying mechanisms through which GABA contributes to plant stress resistance, including its biosynthetic and metabolic pathways, as well as its regulatory roles in enhancing stress tolerance and improving fruit quality. In plants, GABA is primarily synthesized from glutamate by the enzyme glutamate decarboxylase (GAD) and further metabolized by GABA transaminase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH). The accumulation of GABA regulates various physiological and biochemical processes, including the control of stomatal closure, enhancement of antioxidant capacity, maintenance of ionic homeostasis, and stabilization of cellular pH. Moreover, GABA interacts with phytohormones to regulate plant growth, development, and stress tolerance. Notably, increasing GAD expression through genetic engineering has been shown to enhance tolerance to stresses, such as drought, saline-alkali, cold, and heat, in various plants, including tomato, rice, and creeping bentgrass. Additionally, GABA has effectively improved the storage quality of various fruits, including citrus fruits, apples, and strawberries. In conclusion, GABA holds significant research potential and promising applications in agricultural production and plant science. Full article

Polysaccharides isolated from Radix Cyathula officinalis Kuan (RCP) are key bioactive components with immunomodulatory, antioxidant, and anti-inflammatory effects. Their efficacy varies according to their geographic origin and processing methods. However, the systemic anti-aging mechanisms and antioxidant efficacy of RCP have not yet been comprehensively characterized. This study investigated the antioxidant and anti-aging effects of RCP in vitro and in vivo using a Caenorhabditis elegans heat stress model, comparing rRCP (RCP from raw samples) and wRCP (RCP from wine-processed samples) from key production areas. Among these, the RCP collected from the Zhonggang region exhibited the strongest antioxidant activity. Both rRCP and wRCP enhanced worms’ oxidative stress resistance, reduced their ROS levels, increased their antioxidant enzyme activities, prolonged their lifespan, and improved their reproductive capacity under thermal stress. Notably, the wRCP exhibited more pronounced benefits. Additionally, 16S rRNA sequencing revealed that RCP altered the gut microbiota’s composition by increasing its microbial diversity, enriching beneficial bacteria like Bacillus, and decreasing potential pathogens such as Escherichia and Citricoccus. The treatment also led to an increased abundance of Firmicutes and a slight reduction in Bacteroidetes. Collectively, these findings suggest that RCP, particularly wRCP, holds promise as a therapeutic agent for combating oxidative stress and promoting longevity, in part by modulating the gut microbiome. Full article

The gut microbiome is vital in maintaining metabolic health, and dietary habits can significantly impact its composition. A high-fat diet (HFD) can disrupt gut microbial balance, contributing to obesity, insulin resistance, and fatty liver disease. This study explores the potential benefits of heat-killed Enterococcus faecalis EF-2001 (EF-2001) in restoring gut balance and improving metabolic health in HFD-fed mice (HFD-mice). HFD mice administered EF-2001 had 18% less body fat, 22% lower triglyceride levels, and significantly reduced liver enzyme markers, including aspartate aminotransferase (AST) by 28% and alanine aminotransferase (ALT) by 31%. Additionally, EF-2001 improved glucose metabolism, increasing glucose tolerance by 20% and insulin sensitivity by 15%, while reducing fat buildup in the liver by 24%, indicating protection against fatty liver disease. These changes correlated with better metabolic health and reduced inflammation. Our results show that EF-2001 supplementation helped counteract HFD-induced gut imbalances by increasing microbial diversity and supporting beneficial bacteria, such as Akkermansia and Ligilactobacillus spp. Our findings highlight the potential of heat-killed EF-2001 as a promising strategy to restore gut balance and mitigate diet-related metabolic issues. Furthermore, analysis of antibiotic resistance genes (ARGs) revealed that HFD mice exhibited an increased abundance of multidrug resistance genes, particularly those associated with antibiotic efflux mechanisms, such as bcrA, cdeA, and msbA. Notably, EF-2001 supplementation mitigated this increase, reducing the relative abundance of the above ARGs and suggesting a protective role in limiting the spread of antibiotic resistance linked to dysbiosis. EF-2001 offers a compelling approach to managing obesity and metabolic disorders, paving the way for microbiome-based health interventions. Full article

4-coumarate-CoA ligase (4CL) plays a crucial role in the phenylpropanoid metabolic pathway and is a key enzyme involved in plant growth and stress responses. Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) is a major bacterial disease affecting the production of global cruciferous crop-like cabbage (Brassica oleracea var. capitata). However, the role of 4CL genes in cabbage resistance to black rot remains unclear. In this study, transcriptome sequencing was conducted using resistant cabbage MY and susceptible cabbage LY at 0, 6, 24, and 48 h post-inoculation. KEGG analysis identified the enrichment of the phenylpropanoid biosynthesis pathway, and significant expression changes of 4CL genes were determined through the expression heat map. Further genome-wide analysis revealed 43 Bol4CL gene family members on the cabbage genome distributed across nine chromosomes. Gene structure and protein motif analysis revealed similarities in motifs within the same evolutionary branch, but variations in gene structure. A combination of Bol4CL gene expression profiles and differentially expressed genes (DEGs) from the transcriptome identified Bol4CL41 as a key gene for further study. Inoculation of overexpressed Bol4CL41 T₂ generation stably expressed cabbage seedlings demonstrated significantly larger lesion areas compared to wild type cabbage, indicating that Bol4CL41 negatively regulates resistance to black rot in cabbage. The analysis of multi-time point transcriptomes in cabbage and the functional study of the Bol4CL gene family enhance our understanding of the mechanisms underlying plant disease resistance. This provides compelling evidence and experimental support for elucidating the mechanisms of black rot resistance in cabbage. Full article

Xylanases, important enzymes in the food industry, have severely limited use in industrial applications due to insufficient thermal stability. This study focused on improving the thermostability of XynASP, a glycoside hydrolase family 11 (GH11) xylanase from Aspergillus saccharolyticus JOP 1030-1, through modular assembly and rational mutagenesis. By aligning XynASP with nine thermostable GH11 homologs, six variable structural modules (β1, β3, β6, β7, α1, β14) and eight non-conserved residues were identified. Six chimeras (Z1, Z2, Z3, Z4, Z5, Z6) and eight single mutants (S131T, Y133T, A137G, A144T, T147Y, A156R, V198M, and Y204Q) were constructed. Among these, the β3-module-substituted chimera Z2 exhibited a 15.4-fold extended half-life at 45 °C compared to wild-type XynASP. Single-point mutagenesis revealed that V198M showed the highest residual activity after thermal treatment. To further optimize stability, combinatorial mutagenesis was performed: the double mutant A144T/V198M demonstrated a 4.3-fold longer half-life at 50 °C. Combining Z2 with the A144T/V198M mutations yielded the chimeric ZM, which demonstrated a 26.5-fold increase in half-life at 50 °C and a 5.5-fold improvement in catalytic efficiency (197.4 U/mg) compared to wild-type XynASP. Structural analysis and molecular dynamics simulations showed that increased hydrophobic interactions at both the N- and C-termini improved the structural stability of chimeric ZM, while increasing the flexibility of the thumb can offset the negative impact on catalytic activity during thermal stability modification of GH11 xylanase. This study further confirmed that modular assembly is an effective approach for obtaining high-activity, heat-resistant xylanases. This study also notably deepened our understanding of the thermal stability mechanisms of xylanases. Full article

Maize (Zea mays L.) is a staple cereal crop worldwide, but its productivity is significantly affected by extreme weather conditions such as drought and heat stress. Plant growth, physiological processes, and yield potential are all affected by these conditions; as such, resilient maize crops are required to tackle these abiotic challenges. With an emphasis on morphological, physiological, and biochemical reactions, this review paper investigates the processes that underlie resistance to certain environmental challenges. Features including deep root systems, osmotic adaptations, and antioxidant enzyme activity help maize withstand drought. Activation of drought- and heat-responsive genes, accumulation of osmoregulatory compounds, and changes in membrane fluidity are all components of abiotic stress tolerance. Likewise, improved transpiration efficiency, modified photosynthetic processes, and improved heat shock proteins are used to produce heat resistance. Enhancing resilience requires progress in breeding methods, genetic engineering, and agronomic techniques, such as the use of stress-tolerant cultivars, biotechnology interventions, and climate-smart agriculture tactics. A special focus was given to cutting edge technologies like CRISPER-Cas9-mediated recent advances in heat and drought resistance. This review sheds light on recent studies and potential avenues for enhancing resilience to harsh climatic conditions, guaranteeing food security in the face of climate change. Full article

Natural rubber is a widely used biological polymer material because of its excellent comprehensive performance. Nevertheless, the performance of domestic natural rubber cannot meet the requirements for high-end products such as aviation tires, which has become a constraint on the innovation and upgrading of high-end manufacturing enterprises and the enhancement of global competitiveness in China. To solve the bottleneck problem of natural rubber processing technology, this study systematically analyzed the effects of different varieties of fresh latex ratios on the processing and dynamic properties of bio-coagulated natural rubber. By mixing PR107 and Reyan72059 fresh latex with Reyan73397 fresh latex according to proportion, the fresh latex was coagulated by enzyme-assisted microbials, and the effects of the fresh latex ratio on physical and chemical indexes, molecular weight distribution, vulcanization characteristics, processing properties, cross-link density and physical and mechanical properties of the natural rubber were analyzed. The results showed that the aging resistance of natural rubber coagulated with enzyme-assisted microbial decreased, and the aging resistance of natural rubber increased with the increase in the mixing ratio of PR107 and Reyan72059 fresh latex. The proportion of high molecular weight of the natural rubber coagulated with the enzyme-assisted microbial increased, and the fresh latex mixing had little effect on the molecular weight distribution curve. Under the carbon black formulation, the CRI of the enzyme-assisted microbial coagulated natural rubber compound was relatively larger. Under the same strain conditions, the H-3 compound (PR107:Reyan72059:Reyan73397 = 1:1:3) had the best viscoelasticity and the least internal resistance of rubber molecules. In addition, the cross-link density, tensile strength, elongation at break, and tear strength of H-3 vulcanized rubber were the largest, improved by 23.08%, 5.32%, 12.45% and 3.70% compared with the same H-2 vulcanized rubber. In addition, the heat generation performance was reduced by 11.86%, and the wear resistance improved. Full article

The European Food Safety Authority (EFSA) has raised concerns regarding the use of alkaline phosphatase (ALP) as a pasteurization marker in non-cow milk due to compositional differences. This study investigates the thermal inactivation kinetics of ALP in six milk species (cow, sheep, goat, donkey, buffalo and camel) to assess its reliability as an indicator. The thermal inactivation of ALP in different milk types was evaluated by heating samples at 63–75 °C at various times, then measuring residual enzyme activity using a spectrophotometric method. The results revealed a sharp increase in ALP inactivation with rising temperatures, consistent with previous findings on the enzyme’s thermal sensitivity. Notably, donkey milk exhibited the highest ALP inactivation at 72 °C, probably due to lower fat content compared to the rest of milk types studied, while camel milk showed the lowest inactivation rate constant (k_T) at 75 °C, highlighting its higher heat resistance compared to bovine milk. These findings highlight potential limitations of using the ALP test to verify pasteurization in non-bovine milk, which is directly linked to microbial safety, as well as the preservation of nutritional and sensory characteristics. This study reinforces the importance of considering milk composition, particularly fat and protein structures, in optimizing pasteurization conditions for diverse milk varieties. Full article

This study evaluated the effects of dietary dill weed (DW) on growth, hematological profile, digestive enzyme activities, antioxidative response, heat tolerance, gut microbiota composition, and disease resistance in African catfish (Clarias gariepinus). A control diet (basal diet) was compared to three DW diets (DW5, DW10, and DW15) with increasing DW levels (0.5, 1.0, and 1.5%, respectively). After eight weeks, fish fed DW diets exhibited significantly higher growth performance (p < 0.05) compared to the control group, as evidenced by increased final weight (FW), specific growth rate (SGR), and weight gain (WG). Conversely, the feed conversion ratio (FCR), hepatosomatic index (HSI), and visceral somatic index (VSI) were significantly lower (p < 0.05) in fish fed DW diets compared to the control. Dietary DW supplementation significantly enhanced (p < 0.05) hematological profiles, including red blood cell (RBC), white blood cell (WBC), hematocrit (HCT), and hemoglobin (HBG), compared to the control group. Similarly, antioxidant responses, including superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activity, significantly increased (p < 0.05) in fish fed DW diets before or after the heat tolerance assay. Fish fed DW diets displayed a higher relative abundance of beneficial gut microbiota, including Cetobacterium spp., Akkermansia muciniphila, Phocaeicola spp., and Niameybacter massiliensis. Furthermore, dietary DW supplementation stimulated disease resistance against Edwardsiella tarda infection in African catfish. Regression analysis indicated that the optimal DW inclusion level for promoting growth performance and health status in African catfish ranged from 0.229 to 0.433%. Full article

Background: Acyl-CoA oxidase (ACX), a ubiquitous eukaryotic enzyme, catalyzes the initial steps of fatty acid β oxidation and plays an important role in the biosynthesis of jasmonic acid (JA). At present, no studies have been reported on ACX family members of maize and their function in disease resistance. Objectives: This study aims to lay a foundation for clarifying the functions of ACX family genes in maize growth, development, and stress response by conducting a genome-wide identification of ACX family genes in maize, analyzing the expression characteristics of these genes in maize growth and development, hormone treatment and response to biotic and abiotic stresses, and exploring the functions of key genes in the maize disease resistance process through the use of mutants. Methods: ProtParam, TBtools, MEME, MEGA, and IBS tools were used to identify maize ACX family genes and analyze the physicochemical properties of their proteins, chromosome location, phylogenetic relationships among family members, conserved domains, conserved motifs, and cis-acting elements. Meanwhile, the expression patterns of maize ACX family genes in different tissues and their expression patterns under abiotic and biotic stresses were studied by using the data from the maize GDB database and qRT-PCR technology. Moreover, the mutants of ZmACX1, ZmACX3, ZmACX4, and ZmACX5 genes were obtained, and the disease resistance of the mutants was detected to further determine the functions of ACX genes in the maize disease resistance process. This study identified maize ACX family genes using bioinformatics methods. Results: We discovered that six ACX genes in the maize genome are distributed across four different chromosomes. Cluster analysis further classified these genes into three subfamilies. All maize ACX genes possess a conserved ACOX domain, and their promoter regions are enriched with cis-acting elements associated with heat stress and the plant hormone response. Under various tissue, biotic, and abiotic stress conditions, as well as treatments with methyl jasmonate (MeJA) and salicylic acid (SA), the expression levels of maize ACX family genes exhibited significant differences. Notably, the expression levels of ZmACX1, ZmACX3, ZmACX4, and ZmACX5 were significantly up-regulated following stress and pathogen infection, suggesting their involvement in maize growth, development, and disease resistance. To elucidate the function of these genes in maize disease resistance, the resistance of ZmACX1, ZmACX3, ZmACX4, and ZmACX5 mutants to Cochliobolus heterostrophus, Curvularia lunata, and Fusarium graminearum were further examined. The results revealed that compared to the wild-type B73, the lesion area of the mutants was significantly increased after inoculation with pathogens. This directly demonstrated the crucial role of these genes in maize resistance to C. heterostrophus, C. lunata, and F. graminearum. Conclusions: In summary, this study systematically identified maize ACX family genes, and thoroughly investigated their expression patterns and functions in maize disease resistance. Our findings provide valuable insights into the comprehensive understanding of the function and mechanism of maize ACX family genes. Full article

Intestinal stem cells (ISCs) maintain epithelial renewal through their proliferation and differentiation capabilities, responding to various intestinal insults. However, the impact of iturin A, a natural antimicrobial peptide, on ISC viability and its potential to mitigate heat-stable enterotoxin b (STb)-induced intestinal damage remains unclear. Our recent study demonstrated that oral administration of iturin A enhances tight junction protein expression, accelerates crypt-villus regeneration, and restores epithelial barrier integrity in STb-exposed mice. Furthermore, iturin A promotes ISC proliferation and differentiation, significantly increasing the numbers of goblet and Paneth cells in the jejunum following STb exposure. Notably, iturin A regulates intestinal homeostasis by scavenging reactive oxygen species (ROS), while elevating total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) levels in both serum and jejunal mucosa. Mechanistically, iturin A facilitates nuclear factor-erythroid 2- related factor 2 (Nrf2) release by disrupting Kelch-like ECH-associated protein 1 (Keap1), leading to the upregulation of the antioxidant enzyme glutathione peroxidase 4 (GPX4). In conclusion, our findings indicate that iturin A alleviates oxidative stress induced by STb through modulation of the Keap1/Nrf2 pathway and promotes ISC differentiation into goblet and Paneth cells, thereby enhancing resistance to STb-induced damage. Full article

Background/Objectives: The glyceraldehyde-3-phosphate dehydrogenase (GAPDH) enzyme, encoded by OsGAPDHC6, plays a crucial role in glycolysis while participating in various physiological and stress response pathways. Methods: In this study, the expression levels of the OsGAPDHC1 and OsGAPDHC6 genes were investigated over time by treating various abiotic stresses (ABA, PEG, NaCl, heat, and cold) in rice seedlings. Results: As a result, the expression levels of both genes in the ABA-treated group increased continuously for 0–6 h and then de-creased sharply from 12 h onwards. The mutational induction of the GAPDHC6 gene by the CRISPR/Cas9 system generated a stop codon through a 1 bp insertion into protein production. The knockout (KO) lines showed differences in seed length, seed width, and seed thickness compared to wild-type (WT) varieties. In addition, KO lines showed a lower germination rate, germination ability, and germination index of seeds under salt treatment compared to WT, and leaf damage due to 3,3′-diaminobenzidine (DAB) staining was very high due to malondialdehyde (MDA) accumulation. The KO line was lower regarding the expression level of stress-related genes compared to WT. Conclusions: Therefore, the OsGAPDHC6 gene is evaluated as a gene that can increase salt resistance in rice as it actively responds to salt stress in the early stages of growth, occurring from seed germination to just before the tilling stage. Full article