Search Results (709)

The increasing prevalence of antimicrobial resistance, especially in methicillin-resistant Staphylococcus aureus (MRSA), underscores the need for alternative therapies from natural sources. This study investigated the chemical composition, antibacterial activity, and gene expression modulation of Melaleuca cajuputi essential oils. Gas chromatography–mass spectrometry (GC-MS) identified 91 compounds, with naphthalene (23.90%), guaiol (12.92%), caryophyllene oxide (9.69%), D-limonene 98% (8.59%), and gamma terpinene (7.54%) among the most abundant. In Silico molecular docking against MRSA virulence proteins revealed that alloaromadendrene had the strongest binding to toxic shock syndrome toxin-1 (TSST-1) (−7.948 kcal/mol), suggesting high inhibitory potential, while cyclohexane showed weak binding with staphylococcal enterotoxin A (SEA) (−3.532 kcal/mol). Antibacterial assays demonstrated concentration-dependent inhibition, with the zones ranging from 6.33 ± 0.33 mm to 16.67 ± 0.88 mm. MIC and MBC values ranged from 1.56 to 12.5% and 3.13 to 25%, respectively, with most isolates showing bactericidal effects (MBC/MIC ≤ 2). Gene expression analysis of MRSA isolate 4 indicated that sea was moderately upregulated (FC = 1.44), while sec remained unchanged (FC = 1.02). In contrast, fnbA (FC = 0.72), seb (FC = 0.33), and mecA (FC = 0.23) genes were downregulated, and the tsst-1 gene (FC = 0.05) was nearly silent. These findings highlight M. cajuputi essential oils as a promising candidate with both antibacterial efficacy and regulatory effects on MRSA virulence genes. Full article

The discrepancy between the genotypic and phenotypic expression of enterotoxins in S. aureus had long been a significant challenge in toxin detection. However, the accurate and rapid application of Raman spectroscopy for the genotypic and phenotypic characterisation of S. aureus enterotoxins remains problematic. To address this, the present study utilised a single-cell Raman spectra database from 31 S. aureus isolates, acquired via a Raman laser tweezer system. When combined with convolutional neural network analysis, this approach achieved an average accuracy of 99.71% for identifying single-gene toxin types and 99.44% for multi-gene toxin types, with an average phenotypic identification accuracy of 98.71%. Notably, the phenotypic identification accuracy for the three strains carrying the sea and seb genes reached 100%, and the validation accuracy using unknown genotypes and phenotypes exceeded 85%. Furthermore, the CNN analysis identified characteristic spectral peaks for S. aureus enterotoxin genotypes at 1663–1665 cm⁻¹, 1570 cm⁻¹, and 1117–1119 cm⁻¹, corresponding to protein α-helices, guanine, and nucleic acid backbones respectively. Representative peaks for the phenotype were found at 1302–1314 cm⁻¹ and 912–923 cm⁻¹, corresponding to proteins/lipids and polysaccharides, respectively. Representative peaks for different virulence phenotypes carrying multiple enterotoxin genes were located at 1074–1076 cm⁻¹, 1253–1255 cm⁻¹, 1326 cm⁻¹, and 1327 cm⁻¹, corresponding to proteins, nucleic acids, and lipids, respectively. Furthermore, metabolomic analysis of three S. aureus strains (sea+seb+, sea+seb−, sea−seb+) revealed metabolic differences in fatty acids, purines, phenylalanine, and aspartic acid, consistent with the corresponding distinct Raman spectral peaks (1458, 1179, 1406–1409 cm⁻¹). Thus, this study employed S. aureus as a proof-of-concept, establishing for the first time a method combining Raman laser tweezers with convolutional neural networks for identifying S. aureus enterotoxin genotypes and phenotypes. It clarified the Raman spectral differential peaks and their corresponding biomarkers among five classical enterotoxin genotypes and phenotypic strains, providing a novel approach for accurate toxin typing and virulence characterisation. Full article

Background: Deep vein thrombosis (DVT) is one of the most common cardiovascular diseases and is especially prevalent in areas with environmental pollution. Bioaccumulation of toxic heavy metals may lead to deterioration of homeostasis with cellular change, endothelial dysfunction, DNA impairment and cellular signaling. The reason for this is usually the accumulation of thrombogenic toxins in the body as a result of long-term exposure or a lack of regulatory gene expression. In this study, we aimed to measure the minerals that potentially accumulate in the nail. The measurement method was laser-induced breakdown spectroscopy (LIBS), which is a form of atomic emission spectroscopy. It uses a highly energetic laser source to form a plasma of excited atoms emitting light of characteristic wavelengths. It provides accurate quantification and reveals the relationship between tissue accumulation of toxic heavy metals and DVT formation. Methods: Between January 2020 and December 2021, 100 patients diagnosed with lower-extremity deep vein thrombosis were screened in a single tertiary healthcare center. Among them, 50 patients who met the eligibility criteria and consented to participate were included in the study. An additional 50 age-matched healthy volunteers were enrolled as controls. Demographic and clinical characteristics were recorded. Nail samples were obtained from each participant, and elemental emission intensities were quantitatively analyzed using laser-induced breakdown spectroscopy (LIBS). Results: No difference in clinical characteristics was detected between the groups. While iron, calcium and silicon were found to be high in DVT patients, magnesium was found to be low. Regarding the magnesium emission, ROC analysis showed 76–90% specificity and 69–82% sensitivity, respectively. Conclusions: LIBS is a useful method because it is easy to use and can be used with a small sample. According to the results of our study, information about the pathogenesis of DVT was obtained through nail analysis. Therefore, we believe that LIBS analysis is a method that may be useful in determining the causes and predisposing factors for DVT. Full article

Glioblastoma is a highly invasive primary brain tumor with a poor prognosis, highlighting the need for new therapeutic strategies. Toxins derived from Macrodactyla doreensis have attracted attention for their potential anticancer activity. This study evaluated the anticancer and cytotoxic effects of M. doreensis crude venom on two commonly used glioblastoma cell lines (U251 and LN229), which mirror the phenotype of primary tumors. Cell viability and proliferation were assessed using the CCK-8 assay and colony formation assay, while cell migration and invasion capabilities were detected via wound healing assay and Transwell assay. Annexin V/PI staining and PI-based cell cycle analysis indicated that the crude venom significantly induced cell apoptosis and caused S-phase arrest. Proteomic analysis combined with GO and KEGG enrichment analyses as well as bioinformatics approaches showed that M. doreensis crude venom inhibits glioblastoma cell proliferation by downregulating the expression of CDK2, RRM2, and CHEK1, thereby hindering cell cycle progression and regulating the p53 signaling pathway. Notably, the downregulation of these key glioblastoma-related target genes was validated by qPCR. In addition, network pharmacology analysis indicated that several peptide families present in the sea anemone crude venom, including ShK peptides, inhibitor cystine knot (ICK) peptides, and EGF-like peptides, exhibit notable antitumor potential. Combined with AlphaFold2-based structural modeling and molecular docking, these analyses further elucidated the potential molecular mechanisms underlying their interactions with key targets, such as MD-381 with RRM2, MD-322 with CDK2, and MD-429 with CHEK1. Collectively, these findings highlight the therapeutic potential of M. doreensis crude venom and lay a foundation for the subsequent isolation of novel peptides and their further development in glioblastoma treatment. Full article

Exposure to T2 toxin is known to induce hepatotoxicity and gut dysbiosis, yet effective dietary interventions remain underexplored. This study investigates the hepatoprotective and microbiota-modulating effects of lycopene against T2 toxin-induced toxicity in mice. Mice were exposed to T2 toxin with or without lycopene supplementation at low and high doses. The hepatic function, oxidative stress markers, inflammatory gene expression, detoxification pathway activity, and gut microbiota composition were assessed using histological, biochemical, and molecular analyses. T2 toxin exposure resulted in significant weight loss, oxidative liver damage, and gut dysbiosis—marked by a decline in beneficial phyla and an increase in pathogenic bacteria. Hepatic injury was accompanied by upregulated pro-inflammatory genes and downregulated PPAR pathway genes, leading to impaired lipid metabolism and disrupted liver histology. Lycopene supplementation effectively attenuated these effects: it reduced oxidative stress, enhanced antioxidant defense, lowered inflammatory markers, and restored gut microbial balance. Furthermore, lycopene upregulated PPAR pathway and phase I detoxification genes. Notably, the low-dose lycopene regimen demonstrated superior efficacy compared to the high-dose regimen. In conclusion, lycopene, particularly at a low dose, confers significant protection against T2 toxin-induced hepatotoxicity and gut dysbiosis, highlighting its potential as a dietary strategy for mitigating mycotoxin-induced health risks. Full article

Eucalyptus leaf blight is a globally distributed disease caused by Calonectria fungi, with C. pseudoreteaudii being the dominant pathogen in Fujian, China. The crude toxin produced by C. pseudoreteaudii is a key virulent factor. To investigate the resistance mechanism triggered by crude toxin infection, transcriptome sequencing, physiological observations, and qRT-PCR analyses were conducted. Transcriptome analysis of Arabidopsis thaliana treated with C. pseudoreteaudii crude toxin revealed that a flavin-containing monooxygenase 1 gene (AtFMO1) exhibited the highest differential expression with DMSO control. Compared with Arabidopsis ecotype Col-4 (the wild type, WT), AtFMO1 knockout mutant (Δfmo1) plants displayed dose-dependent leaf margin yellowing accompanied by reduced callose deposition and hydrogen peroxide (H₂O₂) accumulation under crude toxin treatment. qRT-PCR analysis of key genes from two immune pathways showed that the salicylic acid-dependent (SA-dependent) pathway was likely Arabidopsis’s primary response pathway for crude toxin. In E. grandis, a total of 38 EgFMOs were identified, with eight EgFMO1s, based on the protein sequence similarity, conserved domain, and motif pattern. qRT-PCR analysis of EgFMO1s revealed two major expression patterns in response to crude toxin treatment: an initial downregulation followed by upregulation, and continuous upregulation. Collectively, these results suggest FMO1 plays a positive role in resistance to C. pseudoreteaudii crude toxin in both A. thaliana and E. grandis. Full article

Monascus spp. are renowned for producing valuable Monascus azaphilone pigments (MonAzPs), yet their biosynthesis is intrinsically linked to the co-production of the mycotoxin citrinin, posing a significant safety challenge and limiting industrial application. Conventional approaches to disrupt citrinin synthesis often inadvertently reduce MonAzPs yield. To circumvent this limitation, we employed a dual-targeting strategy in Monascus ruber. In this study, we selected the mresa1-overexpressed strain—which can produce more MonAzPs and citrinin—as wild strain to construct a pksCT-deleted strain and explore whether pksCT deletion can affect the enhancement of MonAzPs caused by MrEsa1 overexpression. The results showed that the growth, development, and production of MonAzPs in △pksCT-M7::PtrpC-mresa1 were comparable to those in M7::PtrpC-mresa1, showing accelerated growth and higher MonAzPs yields than in M7. In addition, the relative expression levels of genes involved in MonAzPs synthesis in △pksCT-M7::PtrpC-mresa1 and M7::PtrpC-mresa1 showed the same trend compared with M7, indicating that MrEsa1 overexpression can resist the reduction in MonAzPs caused by pksCT deletion. This study establishes a novel and effective paradigm for decoupling desirable metabolite production from toxin synthesis in fungi, providing a strategic framework for the safe and enhanced production of MonAzPs. Full article

Field-evolved resistance of Helicoverpa zea to crops expressing Cry insecticidal proteins from Bacillus thuringiensis (Bt) is widespread across the United States. To comparatively evaluate physiological factors associated with Bt susceptibility, we analyzed two laboratory strains (Benzon and SIMRU) and one field colony obtained from a commercial corn field near Pickens, Arkansas. Biochemical assays of larval midgut extracts showed that Pickens exhibited significantly altered activities of chymotrypsin-like proteases, aminopeptidase N (APN), and alkaline phosphatase (ALP) compared with the SIMRU or Benzon colonies, with differences varying by larval instar. In contrast, trypsin-like protease activities did not differ significantly among the three colonies. Gene expression analyses of ten serine protease genes and seven candidate Cry receptor genes (including cadherin, ATP-binding cassette family C2, ALP, and four APN genes) revealed significant transcriptional differences in the Pickens relative to the lab colonies. Collectively, these results suggest that chymotrypsin-like proteases may play an important role in the activation of Cry toxins in H. zea. Altered chymotrypsin and APN activities, together with differential gene expressions in the Pickens population, likely contribute to reduced Bt susceptibility. The biochemical and molecular differences provide insight into potential physiological factors underlying reduced Bt susceptibility and may inform future Bt resistance monitoring and management strategies. Full article

The transport of metabolites across biological membranes is vital for normal cellular functions, including nutrient uptake, homeostasis, and toxin efflux. In eukaryotes, mitochondrial transporters in the inner mitochondrial membrane (IMM) play a pivotal role in energy production, metabolism, and the biosynthesis of a wide range of compounds. While functional assignments exist for over half of the mitochondrial transporters, emerging high-throughput methodologies underscore the need for reassessment and expansion of the current knowledge, particularly as evidence suggesting functional redundancy and substrate promiscuity has emerged. In this study, we investigated the substrate specificity of five yeast mitochondrial transporters—Crc1 (YOR100c), Ctp1 (YBR291c), Oac1 (YKL120w), Pet9 (YBL030c), and Yhm2 (YMR241w)—via heterologous gene expression in Xenopus laevis oocytes and liquid chromatography-mass spectrometry (LC-MS)-based transport assays. We used two substrate mixtures: a 17-compound organic acid mix and a ¹³C-labeled yeast metabolite extract. Our results revealed broader substrate specificities than previously reported, as partially supported by substrate docking simulations. Pet9 transported several organic acids and amino acids, while Yhm2 showed uptake of nine amino acids and fumaric acid. Additional promiscuous transport activity was observed for Crc1, indicating that these proteins may have more extensive metabolic roles than previously known. This study advances the understanding of yeast mitochondrial transporter function, demonstrating redundancy and broad substrate specificity among mitochondrial carriers. It highlights the importance of utilizing in vivo heterologous systems and physiologically relevant substrate mixtures to elucidate transporter functionality. Full article

Redox (reduction–oxidation) processes underlie all forms of life and are a universal regulatory mechanism that maintains homeostasis and adapts the organism to changes in the internal and external environments. From capturing solar energy in photosynthesis and oxygen generation to fine-tuning cellular metabolism, redox reactions are key determinants of life activity. Proteins containing sulfur- and selenium-containing amino acid residues play a crucial role in redox regulation. Their reversible oxidation by physiological oxidants, such as hydrogen peroxide (H₂O₂), plays the role of molecular switches that control enzymatic activity, protein structure, and signaling cascades. This enables rapid and flexible cellular responses to a wide range of stimuli—from growth factors and nutrient signals to toxins and stressors. Mitochondria, the main energy organelles and also the major sources of reactive oxygen species (ROS), play a special role in redox balance. On the one hand, mitochondrial ROS function as signaling molecules, regulating cellular processes, including proliferation, apoptosis, and immune response, while, on the other hand, their excessive accumulation leads to oxidative stress, damage to biomolecules, and the development of pathological processes. So, mitochondria act not only as a “generator” of redox signals but also as a central link in maintaining cellular and systemic redox homeostasis. Redox signaling forms a multi-layered cybernetic system, which includes signal perception, activation of signaling pathways, the initiation of physiological responses, and feedback regulatory mechanisms. At the molecular level, this is manifested by changes in the activity of redox-regulated proteins of which the redox proteome consists, thereby affecting the epigenetic landscape and gene expression. Physiological processes at all levels of biological organization—from subcellular to systemic—are controlled by redox mechanisms. Studying these processes opens a way to understanding the universal principles of life activity and identifying the biochemical mechanisms whose disruption causes the occurrence and development of pathological reactions. It is important to emphasize that new approaches to redox balance modulation are now actively developed, ranging from antioxidant therapy and targeted intervention on mitochondria to pharmacological and nutraceutical regulation of signaling pathways. This article analyzes the pivotal role of redox balance and its regulation at various levels of living organisms—from molecular and cellular to tissue, organ, and organismal levels—with a special emphasis on the role of mitochondria and modern strategies for influencing redox homeostasis. Full article

Hypertension is a major global health challenge, with excessive dietary salt intake recognized as a key environmental factor contributing to its pathogenesis. However, safe and effective dietary interventions for salt-sensitive hypertension remain limited. Vine tea (Ampelopsis grossedentata), a traditional herbal tea widely consumed for centuries in southern China, has been reported to exhibit antioxidant, anti-inflammatory, and hepatoprotective activities, yet its antihypertensive efficacy and underlying mechanisms remain unclear. In this study, the chemical profile of vine tea aqueous extract (VTE) was characterized by UPLC–Q–TOF–MS, identifying dihydromyricetin, isoquercitrin, and myricetin as the predominant flavonoids. The protective effects of VTE were evaluated in C57BL/6J mice with high-salt-diet (HSD)-induced hypertension. VTE treatment significantly lowered systolic blood pressure and ameliorated cardiac and renal injury, accompanied by reduced inflammation, fibrosis, and cardiac stress-related gene expression. Gut microbiota analysis using 16S rRNA gene sequencing revealed that VTE restored microbial richness and diversity, enriching short-chain fatty acid-producing taxa while suppressing pathogenic Desulfovibrio and Ruminococcus torques. Untargeted plasma metabolomic profiling based on UPLC–Q–TOF–MS further showed that VTE normalized tryptophan, bile acid, and glycerophospholipid metabolism, decreasing the uremic toxin indoxyl sulfate while increasing tauroursodeoxycholic acid. Notably, these protective effects were abolished under antibiotic-induced microbiota depletion, confirming that VTE acts through a gut microbiota-dependent mechanism. Collectively, VTE mitigates salt-induced hypertension and cardiorenal injury by remodeling the gut microbiota–metabolite axis, supporting its potential as a natural dietary intervention for managing hypertension. Full article

In tropical rubber-growing regions, Corynespora leaf fall disease stands as a predominant and economically significant threat to rubber trees. The toxin protein encoded by the cas5 gene is the main pathogenic factor of Corynespora cassiicola. To identify transcription factors capable of binding with the cas5 gene promoter sequence of C. cassiicola, the promoter of the cas5 gene was predicted by bioinformatics, and the 1000 bp promoter of the cas5 gene was isolated to construct a yeast one-hybrid bait vector for self-activation detection. A yeast one-hybrid cDNA expression library of C. cassiicola was constructed to screen for potential transcriptional regulators interacting with the 1000 bp promoter of the cas5 gene. The transcriptional regulators interacting with the cas5 gene were determined by the yeast one-hybrid (Y1H) point-to-point verification experiment. Y1H results showed that the bait vector did not have self-activation. The cDNA library had a titer of 2.516 × 10⁸ cfu/mL and a total clone count of 5.032 × 10⁸. Screening identified 30 candidate transcriptional regulators. Through point-to-point yeast one-hybrid verification, only one of the 30 candidate transcription factors (named CcbZIP3629) showed interaction with cas5. Molecular docking was performed using the AlphaFold3-predicted structure of CcbZIP3629, which revealed its binding to two ACGT core motifs within the promoter. These findings provide the groundwork for elucidating the regulatory mechanism of the cas5 gene, particularly by which CcbZIP3629 mediates the expression of the Cc-Cas5 toxin. Full article

Repeat-in-toxin (RTX) toxins are calcium-dependent exoproteins secreted by diverse Gram-negative bacteria and play central roles in cytotoxicity, immune modulation, and tissue colonization. While their structure and secretion mechanisms are well-characterized, the regulation of RTX toxin expression remains complex and species-specific. This review provides a comprehensive overview of the regulatory networks governing RTX gene expression, highlighting both conserved mechanisms and niche-specific adaptations. RTX genes are controlled by multilayered regulatory systems that integrate global transcriptional control, metabolic regulation, and environmental sensing. Expression is further shaped by host-derived signals, physical contact with host cells, and population-dependent cues. Quorum sensing, post-transcriptional regulation by small RNAs, and post-translational activation mechanisms contribute additional layers of control to ensure precise regulation of toxin production. We also explore how RTX regulation varies across anatomical niches, including the gut, lung, bloodstream, and biofilms, and how it is co-regulated with broader bacterial virulence. Finally, we discuss emerging insights from omics-based approaches and the potential of anti-virulence strategies targeting RTX regulatory pathways. Together, these topics underscore RTX regulation as a model for adaptive virulence control in bacterial pathogens. Full article

Saxitoxin (STX) is one of the most potent marine neurotoxins, produced by several species of freshwater cyanobacteria and marine dinoflagellates. Although omics-based approaches have advanced our understanding of STX biosynthesis in recent decades, the origin, regulation, and ecological drivers of STX in dinoflagellates remain poorly resolved. Specifically, dinoflagellate STX biosynthetic genes (sxt) are extremely fragmented, inconsistently expressed, and unevenly distributed between toxic and non-toxic taxa. Environmental studies further report inconsistent relationships between abiotic factors and STX production, suggesting regulation across multiple genomic, transcriptional, post-transcriptional, and epigenetic levels. These gaps prevent a comprehensive understanding of STX biosynthesis in dinoflagellates and limit the development of accurate predictive models for harmful algal blooms (HABs) and paralytic shellfish poisoning (PSP). Artificial intelligence (AI), including machine learning and deep learning, offers new opportunities in ecological pattern recognition, molecular annotation, and data-driven prediction. This review explores the current state of knowledge and persistent knowledge gaps in dinoflagellate STX research and proposes an AI-integrated multi-omics framework highlighting recommended models for sxt gene identification (e.g., DeepFRI, ProtTrans, ESM-2), evolutionary reconstruction (e.g., PhyloGAN, GNN, PhyloVAE, NeuralNJ), molecular regulation (e.g., MOFA+, LSTM, GRU, DeepMF), and toxin prediction (e.g., XGBoost, LightGBM, LSTM, ConvLSTM). By integrating AI with diverse biological datasets, this novel framework outlines how AI can advance fundamental understanding of STX biosynthesis and inform future applications in HAB monitoring, seafood safety, and PSP risk management in aquaculture and fisheries. Full article

Glomerella leaf spot (GLS), mainly caused by Colletotrichum fructicola, is a destructive disease of apple. However, the underlying pathogenesis mechanisms of GLS are still largely obscure. Previous infection transcriptome analysis showed that transcription factor CfGti1 was induced during leaf infection. The present study confirms that the CfGti1 gene is strongly expressed in conidia and early infection. To identify functions performed, we generated gene deletion mutant ΔCfGti1 by homologous recombination. Phenotypic analysis revealed that ΔCfGti1 lost pathogenicity to apple leaves by blocking appressorium-mediated host penetration, although penetration pegs still developed on cellophane. In addition, ΔCfGti1 colonization and hyphal extension in wounded apple fruit were dramatically decreased. The ΔCfGti1 mutant exhibited defects in growth and development of hyphae, which may be partly responsible for its inability to colonize apple. Comparative transcriptome and qRT-PCR analyses suggested that CfGti1 regulated appressorium-mediated host penetration by modulating genes related to metabolism of appressorial lipid droplets. Interestingly, CfGti1 also regulated the expression of ybtS and AKT1 or AFT1-1 related to biosynthesis of AK and AF host-specific toxins. This study demonstrated that CfGti1 is a pivotal regulator for apple GLS pathogenesis in C. fructicola. Full article