Nature. 2025 Feb 26. doi: 10.1038/s41586-025-08635-6. Online ahead of print.

ABSTRACT

Metabolic flux, or the rate of metabolic reactions, is one of the most fundamental metrics describing the status of metabolism in living organisms. However, measuring fluxes across the entire metabolic network remains nearly impossible, especially in multicellular organisms. Computational methods based on flux balance analysis have been used with genome-scale metabolic network models to predict network-level flux wiring1-6. However, such approaches have limited power because of the lack of experimental constraints. Here, we introduce a strategy that infers whole-animal metabolic flux wiring from transcriptional phenotypes in the nematode Caenorhabditis elegans. Using a large-scale Worm Perturb-Seq (WPS) dataset for roughly 900 metabolic genes7, we show that the transcriptional response to metabolic gene perturbations can be integrated with the metabolic network model to infer a highly constrained, semi-quantitative flux distribution. We discover several features of adult C. elegans metabolism, including cyclic flux through the pentose phosphate pathway, lack of de novo purine synthesis flux and the primary use of amino acids and bacterial RNA as a tricarboxylic acid cycle carbon source, all of which we validate by stable isotope tracing. Our strategy for inferring metabolic wiring based on transcriptional phenotypes should be applicable to a variety of systems, including human cells.

PMID:40011784 | DOI:10.1038/s41586-025-08635-6

Nat Rev Gastroenterol Hepatol. 2025 Feb 26. doi: 10.1038/s41575-025-01042-2. Online ahead of print.

ABSTRACT

The demonstration that Helicobacter pylori is a pathogenic bacterium with marked carcinogenic potential has paved the way for new preventive approaches for gastric cancer. Although decades of research have uncovered complex interactions of H. pylori with epithelial cells, current insights have refined our view on H. pylori-associated carcinogenesis. Specifically, the cell-type-specific effects on gastric stem and progenitor cells deep in gastric glands provide a new view on the ability of the bacteria to colonize long-term, manipulate host responses and promote gastric pathology. Furthermore, new, large-scale epidemiological data have shed light on factors that determine why only a subset of carriers progress to gastric cancer. Currently, technological advances have brought yet another revelation: H. pylori is far from the only microorganism able to colonize the stomach. Instead, the stomach is colonized by a diverse gastric microbiota, and there is emerging evidence for the occurrence and pathological effect of dysbiosis resulting from an aberrant interplay between H. pylori and the gastric mucosa. With the weight of this evidence mounting, here we consider how the lessons learned from H. pylori research inform and synergize with this emerging field to bring a more comprehensive understanding of the role of microbes in gastric carcinogenesis.

PMID:40011753 | DOI:10.1038/s41575-025-01042-2

Nat Microbiol. 2025 Feb 26. doi: 10.1038/s41564-025-01935-7. Online ahead of print.

ABSTRACT

Bacteriophages constitute one of the largest reservoirs of genes of unknown function in the biosphere. Even in well-characterized phages, the functions of most genes remain unknown. Experimental approaches to study phage gene fitness and function at genome scale are lacking, partly because phages subvert many modern functional genomics tools. Here we leverage RNA-targeting dCas13d to selectively interfere with protein translation and to measure phage gene fitness at a transcriptome-wide scale. We find CRISPR Interference through Antisense RNA-Targeting (CRISPRi-ART) to be effective across phage phylogeny, from model ssRNA, ssDNA and dsDNA phages to nucleus-forming jumbo phages. Using CRISPRi-ART, we determine a conserved role of diverse rII homologues in subverting phage Lambda RexAB-mediated immunity to superinfection and identify genes critical for phage fitness. CRISPRi-ART establishes a broad-spectrum phage functional genomics platform, revealing more than 90 previously unknown genes important for phage fitness.

PMID:40011704 | DOI:10.1038/s41564-025-01935-7

Nat Med. 2025 Feb 26. doi: 10.1038/s41591-025-03533-w. Online ahead of print.

ABSTRACT

The role of endothelial cell (EC) dysfunction in contributing to an individual's susceptibility to coronary atherosclerosis and how low-density lipoprotein cholesterol (LDL-C) concentrations might modify this relationship have not been previously studied. Here, from an examination of genome-wide significant single nucleotide polymorphisms associated with coronary artery disease (CAD), we identified variants with effects on EC function and constructed a 35 single nucleotide polymorphism polygenic risk score comprising these EC-specific variants (EC PRS). The association of the EC PRS with the risk of incident cardiovascular disease was tested in 3 cohorts: a primary prevention population in the UK Biobank (UKBB; n = 348,967); a primary prevention cohort from a trial that tested a statin (JUPITER, n = 8,749); and a secondary prevention cohort that tested a PCSK9 inhibitor (FOURIER, n = 14,298). In the UKBB, the EC PRS was independently associated with the risk of incident CAD (adjusted hazard ratio (aHR) per 1 s.d. of 1.24 (95% CI 1.21-1.26), P < 2 × 10-16). Moreover, LDL-C concentration significantly modified this risk: the aHR per 1 s.d. was 1.26 (1.22-1.30) when LDL-C was 150 mg dl-1 but 1.00 (0.85-1.16) when LDL-C was 50 mg dl-1 (Pinteraction = 0.004). The clinical benefit of LDL-C lowering was significantly greater in individuals with a high EC PRS than in individuals with low or intermediate EC PRS, with relative risk reductions of 68% (HR 0.32 (0.18-0.59)) versus 29% (HR 0.71 (0.52-0.95)) in the primary prevention cohort (Pinteraction = 0.02) and 33% (HR 0.67 (0.53-0.83)) versus 8% (HR 0.92 (0.82-1.03)) in the secondary prevention cohort (Pinteraction = 0.01). We conclude that EC PRS quantifies an independent axis of CAD risk that is not currently captured in medical practice and identifies individuals who are more sensitive to the atherogenic effects of LDL-C and who would potentially derive substantially greater benefit from aggressive LDL-C lowering.

PMID:40011692 | DOI:10.1038/s41591-025-03533-w

Nat Cell Biol. 2025 Feb 26. doi: 10.1038/s41556-025-01622-z. Online ahead of print.

ABSTRACT

Recent advancements in functional genomics have provided an unprecedented ability to measure diverse molecular modalities, but predicting causal regulatory relationships from observational data remains challenging. Here, we leverage pooled genetic screens and single-cell sequencing (Perturb-seq) to systematically identify the targets of signalling regulators in diverse biological contexts. We demonstrate how Perturb-seq is compatible with recent and commercially available advances in combinatorial indexing and next-generation sequencing, and perform more than 1,500 perturbations split across six cell lines and five biological signalling contexts. We introduce an improved computational framework (Mixscale) to address cellular variation in perturbation efficiency, alongside optimized statistical methods to learn differentially expressed gene lists and conserved molecular signatures. Finally, we demonstrate how our Perturb-seq derived gene lists can be used to precisely infer changes in signalling pathway activation for in vivo and in situ samples. Our work enhances our understanding of signalling regulators and their targets, and lays a computational framework towards the data-driven inference of an 'atlas' of perturbation signatures.

PMID:40011560 | DOI:10.1038/s41556-025-01622-z

Nat Commun. 2025 Feb 26;16(1):1995. doi: 10.1038/s41467-025-57182-1.

ABSTRACT

Hepatitis E virus (HEV) causes 3.3 million symptomatic cases and 44,000 deaths per year. Chronic infections can arise in immunocompromised individuals, and pregnant women may suffer from fulminant disease as a consequence of HEV infection. Despite these important implications for public health, no specific antiviral treatment has been approved to date. Here, we report combined functional, biochemical, and X-ray crystallographic studies that characterize the human antibody response in convalescent HEV patients. We identified a class of potent and broadly neutralizing human antibodies (bnAbs), targeting a quaternary epitope located at the tip of the HEV capsid protein pORF2 that contains an N-glycosylation motif and is conserved across members of the Hepeviridae. These glycan-sensitive bnAbs specifically recognize the non-glycosylated pORF2 present in infectious particles but not the secreted glycosylated form acting as antibody decoy. Our most potent bnAb protects human liver-chimeric mice from intraperitoneal HEV challenge and co-housing exposure. These results provide insights into the bnAb response to this important emerging pathogen and support the development of glycan-sensitive antibodies to combat HEV infection.

PMID:40011441 | DOI:10.1038/s41467-025-57182-1

Life Sci. 2025 Feb 24:123507. doi: 10.1016/j.lfs.2025.123507. Online ahead of print.

ABSTRACT

AIMS: The association between aging-related hyperphosphatemia and sarcopenia has been documented, and evidence suggests that inflammaging is involved in the manifestation of sarcopenia. The present study investigates whether hyperphosphatemia triggers inflammation, thereby inducing the appearance of sarcopenia along with the cytokines involved in these processes.

MATERIALS AND METHODS: RAW 264.7 macrophages were incubated with β-glycerophosphate (BGP), as a phosphate donor, at different time intervals, to assess the production of proinflammatory markers. Conditioned medium from macrophages was collected and added to cultured C2C12 myoblasts to analyse whether proinflammatory molecules, released by macrophages, modified myogenic differentiation, cell senescence or myokine IL-15 expression. A neutralising antibody anti-TNF-α and recombinant IL-15 were added to evaluate the role of these cytokines in the observed effects. Additionally, TNF-α, IL-15, serum phosphate, and sarcopenia signs were evaluated in 5-month-old mice, 24-month-old mice and 24-month-old mice fed with a hypophosphatemic diet.

KEY FINDINGS: BGP increased TNF-α expression in macrophages through NFkB activation. Conditioned medium from BGP-treated macrophages impaired myogenic differentiation in differentiating myoblasts and promoted cellular senescence and reduced IL-15 expression in undifferentiated myoblasts. These effects were mediated by TNF-α. Old mice displayed reduced expression of muscle IL-15 and elevated circulating TNF-α, along with increased serum phosphate levels, which correlated with the appearance of sarcopenia indicators. The hypophosphatemic diet prevented these changes in old mice.

SIGNIFICANCE: Hyperphosphatemia induces TNF-α production in macrophages, which contributes to the reduced expression of muscular IL-15. This mechanism may play a role in inducing sarcopenia in elderly mice.

PMID:40010633 | DOI:10.1016/j.lfs.2025.123507

Int J Sports Physiol Perform. 2025 Feb 26:1-4. doi: 10.1123/ijspp.2024-0303. Online ahead of print.

ABSTRACT

BACKGROUND: The role of high-volume low-intensity training for enhancing endurance performance has gained growing interest in recent years. Specifically, so-called "zone 2 training" is currently receiving much attention, and many propose that this is the target intensity at which a large proportion of total endurance training should be performed. However, despite the popularity of this concept, there is no clear consensus among coaches, athletes, and scientists regarding the definition of zone 2 training.

PURPOSE: This commentary summarizes the perspectives, experience, and knowledge of an expert panel of 14 applied sport scientists and professional coaches with the aim of providing insight and a basis for definitional consensus on zone 2 training. Moreover, potential training strategies at this intensity are proposed, and the expected physiological adaptations when exercising at this intensity and related research gaps are also discussed.

RESULTS: Experts reached consensus that zone 2 training should preferably be performed at intensities located immediately below the first lactate or ventilatory threshold through continuous, variable, or interval-type sessions. Furthermore, experts expected a broad range of central and peripheral adaptations from zone 2 training. These expected adaptations might not be unique to zone 2 and could also be induced with sessions performed at slightly higher and lower intensities.

CONCLUSIONS: This commentary provides practical insight and unified criteria regarding the preferred intensity, duration, and session type for the optimization of zone 2 training based on the perspectives of acknowledged sport scientists and professional coaches.

PMID:40010355 | DOI:10.1123/ijspp.2024-0303

Phytomedicine. 2025 Feb 14;139:156518. doi: 10.1016/j.phymed.2025.156518. Online ahead of print.

ABSTRACT

BACKGROUND: Drug discovery from nature has a long, ethnopharmacologically-based background. Today, natural resources are undeniably vital reservoirs of active molecules or drug leads. Advances in (bio)informatics and computational biology emphasized the role of herbal medicines in the drug discovery pipeline.

PURPOSE: This review summarizes bioinformatic approaches applied in recent drug discovery from nature.

STUDY DESIGN: It examines advancements in molecular networking, pathway analysis, network pharmacology within a systems biology framework and AI for assessing the therapeutic potential of herbal preparations.

METHODS: A comprehensive literature search was conducted using Pubmed, SciFinder, and Google Database. Obtained data was analyzed and organized in subsections: AI, systems biology integrative approach, network pharmacology, pathway analysis, molecular networking, structure-based virtual screening.

RESULTS: Bioinformatic approaches is now essential for high-throughput data analysis in drug target identification, mechanism-based drug discovery, drug repurposing and side-effects prediction. Large datasets obtained from "omics" approaches require bioinformatic calculations to unveil interactions, and patterns in disease-relevant conditions. These tools enable databases annotations, pattern-matching, connections discovery, molecular relationship exploration, and data visualisation.

CONCLUSION: Despite the complexity of plant metabolites, bioinformatic approaches assist in characterization of herbal preparations and selection of bioactive molecule. It is perceived as powerful tool for uncovering multi-target effects and potential molecular mechanisms of compounds. By integrating multiple networks that connect gene-disease, drug-target and gene-drug-target, drug discovery from natural sources is experiencing a remarkable comeback.

PMID:40010031 | DOI:10.1016/j.phymed.2025.156518

Biochem Cell Biol. 2025 Feb 26. doi: 10.1139/bcb-2024-0287. Online ahead of print.

ABSTRACT

Estrogen (E2) regulates the differentiation and proliferation of mammary progenitor cells by modulating the transcription of multiple genes. One of the genes that is downregulated by E2 is SOX2, a transcription factor associated with stem and progenitor cells that is overexpressed during breast tumourigenesis. To elucidate the mechanisms underlying E2-mediated SOX2 repression, we investigated epigenome and transcriptome changes following short- and long-term E2 exposure in breast cancer cells. We found that short-term E2 exposure reduces chromatin accessibility at the downstream SOX2 SRR134 enhancer, decreasing SOX2 expression. In contrast, long-term E2 exposure completely represses SOX2 transcription while maintaining accessibility at the SRR124-134 enhancer cluster, keeping it poised for reactivation. This repression was accompanied by widespread epigenome and transcriptome changes associated with commitment towards a more differentiated and less invasive luminal phenotype. Finally, we identified a role for the transcription factor NFIB in this process, suggesting it collaborates with the estrogen receptor to mediate SOX2 repression and genome-wide epigenome accessibility changes.

PMID:40009831 | DOI:10.1139/bcb-2024-0287

Sci Adv. 2025 Feb 28;11(9):eadv2067. doi: 10.1126/sciadv.adv2067. Epub 2025 Feb 26.

ABSTRACT

3D organization of the genome plays a critical role in regulating gene expression. How 3D-genome organization differs among different cell types and relates to cell type-dependent transcriptional regulation remains unclear. Here, we used genome-scale DNA and RNA imaging to investigate 3D-genome organization in transcriptionally distinct cell types in the mouse cerebral cortex. We uncovered a wide spectrum of differences in the nuclear architecture and 3D-genome organization among different cell types, ranging from the size of the cell nucleus to higher-order chromosome structures and radial positioning of chromatin loci within the nucleus. These cell type-dependent variations in nuclear architecture and chromatin organization exhibit strong correlations with both the total transcriptional activity of the cell and transcriptional regulation of cell type-specific marker genes. Moreover, we found that the methylated DNA binding protein MeCP2 promotes active-inactive chromatin segregation and regulates transcription in a nuclear radial position-dependent manner that is highly correlated with its function in modulating active-inactive chromatin compartmentalization.

PMID:40009678 | DOI:10.1126/sciadv.adv2067

Proc Natl Acad Sci U S A. 2025 Mar 4;122(9):e2417695122. doi: 10.1073/pnas.2417695122. Epub 2025 Feb 26.

ABSTRACT

Advances in sequencing technology have unveiled examples of nucleus-encoded polycistrons, once considered rare. Exclusively polycistronic transcripts are prevalent in green algae, although the mechanism by which multiple polypeptides are translated from a single transcript is unknown. Here, we used bioinformatic and in vivo mutational analyses to evaluate competing mechanistic models for translation of bicistronic mRNAs in green algae. High-confidence manually curated datasets of bicistronic loci from two divergent green algae, Chlamydomonas reinhardtii and Auxenochlorella protothecoides, revealed a preference for weak Kozak-like sequences for ORF 1 and an underrepresentation of potential initiation codons before the ORF 2 start codon, which are suitable conditions for leaky ribosome scanning to allow ORF 2 translation. We used mutational analysis in A. protothecoides to test the mechanism. In vivo manipulation of the ORF 1 Kozak-like sequence and start codon altered reporter expression at ORF 2, with a weaker Kozak-like sequence enhancing expression and a stronger one diminishing it. A synthetic bicistronic dual reporter demonstrated inversely adjustable activity of green fluorescent protein expressed from ORF 1 and luciferase from ORF 2, depending on the strength of the ORF 1 Kozak-like sequence. Our findings demonstrate that translation of multiple ORFs in green algal bicistronic transcripts is consistent with episodic leaky scanning of ORF 1 to allow translation at ORF 2. This work has implications for the potential functionality of upstream open reading frames (uORFs) found across eukaryotic genomes and for transgene expression in synthetic biology applications.

PMID:40009642 | DOI:10.1073/pnas.2417695122

Appl Biochem Biotechnol. 2025 Feb 26. doi: 10.1007/s12010-025-05200-9. Online ahead of print.

ABSTRACT

Colorectal cancer (CRC) is one of the common deadliest cancers worldwide. In Malaysia, the numbers of new CRC cases were horrific and worrisome. Telomerase is both prognostic indicator and predictor of carcinogenesis in CRC patients. Berberine, a telomerase inhibitor, was used in clinical trials and metabolomic studies; however, the association of telomerase with metabolites and metabolic pathways was not fully understood. Colorectal cancer cell line HCT 116 was cultured and treated with 10.54 µg/mL berberine. The cells were harvested at different time points to conduct subsequent analyses. The methods used in this research were real time-polymerase chain reaction (RT-PCR) to assess RNA expressions; Western blot to determine protein levels; TELOTAGGG Telomerase PCR ELISA to determine relative telomerase activity (RTA); 4',6-diamidino-2-phenylindole (DAPI) staining to determine percentage of nuclei damage; fluorescence microscopy for cell area; spectrophotometric potassium iodide assay for intracellular hydrogen peroxide concentration [H2O2]; as well as liquid chromatography mass spectrometry (LCMS) and tandem mass spectrometry (MS/MS) to investigate the intracellular metabolites. Partial least square-discriminant analysis (PLS-DA) score plot exhibited an improved separation compared to principal component analysis (PCA) when metabolomic data analysis of HCT 116 at various berberine treatment durations was conducted. Time and berberine treatment had an impact on RTA in HCT 116. RTA was discovered to be positively and negatively correlated to 14 and 2 metabolites, respectively. Glutamic acid was consistently found correlated to RTA. Other four metabolites, i.e., MG(14:0), [3-[hydroxy(phosphonooxy)phosphoryl]oxyphenyl] phosphono hydrogen phosphate), (3S,6S)-6-[[(3S,6R)-6-[(2S,3S,5S)-2,5-diiodo-4-methoxy-6-methyloxan-3-yl]oxy-3,4,5-trihydroxyoxan-2-yl]methoxy]-3,4,5-trihydroxyoxane-2-carboxylic acid, and 1-[5-O-(5'-adenylyloxyphosphonyl)-beta-D-ribofuranosyl]-5-amino-1H-imidazole-4-carboxamide, were newly discovered to be connected to RTA in HCT 116. Four metabolic pathways that majorly affected shared glutamic acid and glutamine. Nitrogen metabolism, D-glutamine and D-glutamate metabolism, glyoxylate and dicarboxylate metabolism, and aminoacyl-tRNA biosynthesis have been identified to be associated with RTA. Network analyses hinted that glutamic acid was also associated with oxidative stress mechanism. The multiple roles glutamic acid acted in diverse metabolic pathways and interaction networks emphasized the importance of glutamic acid in HCT 116 regarding RTA. This research establishes the association between RTA and several chosen RNAs, proteins, metabolites, and oxidative stress mechanisms, consequential in morphological alteration in HCT 116, to expand the knowledge of the intricate biological relationships and telomerase mechanism in CRC.

PMID:40009339 | DOI:10.1007/s12010-025-05200-9

Mol Oncol. 2025 Feb 26. doi: 10.1002/1878-0261.70005. Online ahead of print.

ABSTRACT

Glioblastoma (GBM) is the most aggressive and lethal type of glioma, characterized by aberrant expression of noncoding RNAs including circular RNAs (circRNAs). CircRNAs may impact cellular processes by interacting with other molecules-like RNA-binding proteins (RBPs). The diagnostic value of circRNA and circRNA/RBP complexes is still largely unknown. To explore circRNA and RBP transcript expression in GBM, we performed and further analyzed RNA-seq data from GBM patients' primary and recurrent tumor samples. We identified circRNAs differentially expressed in primary tumors, the circRNA progression markers in recurrent GBM samples, and the expression profile of RBP genes. Furthermore, we demonstrated the clinical potential of circRNAs and RBPs in GBM and proposed them as stratification markers in de novo assembled tumor subtypes. Additionally, we experimentally validated the subcellular localization of select circRNAs and their interactions with FUS. Subsequently, we showed that circARID1A may play a role in promoting GBM cell proliferation. Overall, we described circRNA-RBP interactions that could play a regulatory role in gliomagenesis and GBM progression and provided a list of molecular players in GBM for further extensive studies.

PMID:40008750 | DOI:10.1002/1878-0261.70005

RSC Med Chem. 2025 Feb 11. doi: 10.1039/d4md00475b. Online ahead of print.

ABSTRACT

The stimulator of interferon genes (STING) has been an attractive target in cancer immunotherapy. However, natural ligand cyclic dinucleotides (CDNs) and CDN derivatives have demonstrated limited efficacy in clinical trials. This limitation stems from the inherent structure of CDNs, which leads to enzymatic degradation, poor cell internalisation, rapid clearance from the tumour microenvironment, and dose-limiting toxicity. In this study, we developed an amphipathic STING agonist, termed albumin-binding CDNs (AlbiCDNs), to enhance the efficacy of c-di-GMP (CDG) via a lipid-conjugated strategy. The lipid provided a platform for albumin hitchhiking, which facilitated the cytoplasmic delivery of CDG without the use of any exogenous components. In addition, incorporating a stimuli-responsive lipid motif further enhanced the cellular release of CDG. Our results indicated that CDG-1C14, an AlbiCDN, efficiently stimulated the maturation and activation of antigen-presenting cells through STING activation. Furthermore, CDG-1C14 exhibited a significant inhibitory effect on the tumour therapeutic model. Therefore, AlbiCDN is a potent platform for cancer immunotherapy that can expedite clinical translation.

PMID:40008189 | PMC:PMC11848399 | DOI:10.1039/d4md00475b

Front Microbiol. 2025 Feb 11;16:1495971. doi: 10.3389/fmicb.2025.1495971. eCollection 2025.

ABSTRACT

INTRODUCTION: Bacteroides fragilis (Bf)'s T6SS locus has been characterized and shown to have functional activity in competition experiments. It has been demonstrated that symbiont nontoxigenic Bf strains have a more effective "weapon" effect on pathogenic Bf, which is realized through the activity of effector-immune (E-I) protein pairs. Intensive study of the T6SS structure has led to an understanding of certain issues related to its functional activity, but the exact regulatory mechanisms of E-I protein pair activity remain unclear. Proteomic annotation of T6SS components and detailed descriptions of all immune-effector pairs are currently available. In this research, we performed detailed proteogenomic analysis and subsequent proteomic annotation of the T6SS components of the toxigenic Bf BOB25.

MATERIAL AND METHODS: Fractionated cells, cultivated media and vesicles were prepared for proteome analysis by HPLC-MS/MS. Proteogenomic annotation and comparative genomic study of the T6SS loci of the toxigenic Bf BOB25 were carried out by comparison with the reference genomes of the following Bf strains: JIM10, NCTC 9343 and 638R.

RESULTS: According to the data obtained, T6SS components were represented in all types of the analysed samples. The following components of the T6SS were identified in culture media and cells: ClpV (TssH), TssK, TssC, TssB, Hcp (TssD), and TetR. The predicted effector protein AKA51715.1 (VU15_08315) was also detected in media. The greatest amount of T6SS proteins, including the Hcp protein, was detected in the vesicle samples, which was also observed by TEM. Potential effectors, including AKA51715.1 (VU15_08315), AKA51716.1 (VU15_08320), AKA51728.1 (VU15_08385) and the immune protein AKA51727.1 (VU15_08380), were detected in vesicles.

DISCUSSION: The presence of the immune and effector proteins in the Bf secretome indicates the high activity of the T6SS without bacterial competition. It is possible that the T6SS is also used by bacteria to regulate population size by altering the activity of different repertoires of E-I pairs.

PMID:40008042 | PMC:PMC11854122 | DOI:10.3389/fmicb.2025.1495971

Front Microbiol. 2025 Feb 11;16:1541797. doi: 10.3389/fmicb.2025.1541797. eCollection 2025.

ABSTRACT

The ArcAB two-component system includes a histidine kinase sensor (ArcB) and a regulator (ArcA) that respond to changes in cell oxygen availability. The ArcA transcription factor activates genes related to metabolism, membrane permeability, and virulence, and its presence is required for pathogenicity in Salmonella Typhimurium, which can be phosphorylated independently of its cognate sensor, ArcB. In this study, we aimed to characterize the transcriptional response to hypochlorous acid (HOCl) mediated by the presence of the ArcB sensor. HOCl is a powerful microbicide widely used for sanitization in industrial settings. We used wild-type S. Typhimurium and the mutant lacking the arcB gene exposed to NaOCl to describe the global transcriptional response. We also infected murine neutrophils to evaluate the expression levels of relevant genes related to the resistance and infection process while facing ROS-related stress. Our results indicate that the absence of the arcB gene significantly affects the ability of S. Typhimurium to grow under HOCl stress. Overall, 6.6% of Salmonella genes varied their expression in the mutant strains, while 8.6% changed in response to NaOCl. The transcriptional response associated with the presence of ArcB is associated with metabolism and virulence, suggesting a critical role in pathogenicity and fitness, especially under ROS-related stress. Our results show that ArcB influences the expression of genes associated with fatty acid degradation, protein secretion, cysteine and H2S biosynthesis, and translation, both in vitro and under conditions found within neutrophils. We found that protein carbonylation is significantly higher in the mutant strain than in the wild type, suggesting a critical function for ArcB in the response and repair processes. This study contributes to the understanding of the pathogenicity and adaptation mechanisms that Salmonella employs to establish a successful infection in its host.

PMID:40008041 | PMC:PMC11850377 | DOI:10.3389/fmicb.2025.1541797

Biophys J. 2025 Feb 25:S0006-3495(25)00106-7. doi: 10.1016/j.bpj.2025.02.015. Online ahead of print.

ABSTRACT

The molecular interactions between a fungal membrane model and SJGAP, a 32-amino-acid antimicrobial peptide (AMP) derived from skipjack tuna GAPDH, as well as four analogs, were investigated using molecular dynamics simulations and Fourier-transform infrared (FTIR) spectroscopy. In a previous study, Analog 7, modified by replacing three alanine residues with leucine residues, exhibited unique antifungal activity without any antibacterial effect. This contrasts with other analogs, which showed both antifungal and antibacterial effects. In the present study, Analog 7 displayed the strongest interactions with the membrane's hydrophobic core, inserting more deeply and causing significantly greater membrane deformation and thinning compared to the other analogs. Its presence caused significant membrane deformation, evident from the displacement of both the phosphate groups and terminal methyls of the lipids. Notably, Analog 7 was the only analog to induce a marked depletion of ergosterol around the peptide insertion site. Fourier-transform infrared (FTIR) spectroscopy experiments further confirmed the distinctive impact of Analog 7 on a fungal membrane model. The combined results from molecular dynamics simulations and spectroscopy emphasize the critical role of leucine substitutions in Analog 7, particularly at residues 18 and 19 within the central α helix, in promoting membrane thinning and inducing ergosterol depletion, suggesting increased membrane permeabilization, which could explain its previously reported antifungal specificity. This study provides the first insights into the molecular interactions between a GAPDH-derived AMP and a fungal membrane model, offering valuable information about its antifungal mechanism of action.

PMID:40007119 | DOI:10.1016/j.bpj.2025.02.015

Sensors (Basel). 2025 Feb 19;25(4):1264. doi: 10.3390/s25041264.

ABSTRACT

Perennial ryegrass is an important temperate grass used for forage and turf worldwide. It forms symbiotic relationships with endophytic fungi (endophytes), conferring pasture persistence and resistance to herbivory. Endophyte performance can be influenced by the host genotype, as well as environmental factors such as seed storage conditions. It is therefore critical to confirm seed quality and purity before a seed is sown. DNA-based methods are often used for quality control purposes. Recently, near-infrared spectroscopy (NIRS) coupled with hyperspectral imaging was used to discriminate perennial ryegrass cultivars and endophyte presence in individual seeds. Here, a NIRS-based analysis of bulk seeds was used to develop models for discriminating perennial ryegrass cultivars (Alto, Maxsyn, Trojan and Bronsyn), each hosting a suite of eight to eleven different endophyte strains. Sub-sampling, six per bag of seed, was employed to minimize misclassification error. Using a nested PLS-DA approach, cultivars were classified with an overall accuracy of 94.1-98.6% of sub-samples, whilst endophyte presence or absence was discriminated with overall accuracies between 77.8% and 96.3% of sub-samples. Hierarchical classification models were developed to discriminate bulked seed samples quickly and easily with minimal misclassifications of cultivars (<8.9% of sub-samples) or endophyte status within each cultivar (<11.3% of sub-samples). In all cases, greater than four of the six sub-samples were correctly classified, indicating that innate variation within a bag of seeds can be overcome using this strategy. These models could benefit turf- and pasture-based industries by providing a tool that is easy, cost effective, and can quickly discriminate seed bulks based on cultivar and endophyte content.

PMID:40006495 | DOI:10.3390/s25041264

Pharmaceuticals (Basel). 2025 Jan 24;18(2):152. doi: 10.3390/ph18020152.

ABSTRACT

In the original publication [...].

PMID:40006093 | DOI:10.3390/ph18020152