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PubMed2024

Role of the Pseudomonas plecoglossicida fliL gene in immune response of infected hybrid groupers (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂).

Pseudomonas plecoglossicida, a gram-negative bacterium, is the main pathogen of visceral white-point disease in marine fish, responsible for substantial economic losses in the aquaculture industry. The FliL protein, involved in torque production of the bacterial flagella motor, is essential for the pathogenicity of a variety of bacteria. In the current study, the fliL gene deletion strain (ΔfliL), fliL gene complement strain (C-ΔfliL), and wild-type strain (NZBD9) were compared to explore the influence of the fliL gene on P. plecoglossicida pathogenicity and its role in host immune response. Results showed that fliL gene deletion increased the survival rate (50%) and reduced white spot disease progression in the hybrid groupers. Moreover, compared to the NZBD9 strain, the ΔfliL strain was consistently associated with lower bacterial loads in the grouper spleen, head kidney, liver, and intestine, coupled with reduced tissue damage. Transcriptomic analysis identified 2 238 differentially expressed genes (DEGs) in the spleens of fish infected with the ΔfliL strain compared to the NZBD9 strain. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, the DEGs were significantly enriched in seven immune system-associated pathways and three signaling molecule and interaction pathways. Upon infection with the ΔfliL strain, the toll-like receptor (TLR) signaling pathway was activated in the hybrid groupers, leading to the activation of transcription factors (NF-κB and AP1) and cytokines. The expression levels of proinflammatory cytokine-related genes IL-1β, IL-12B, and IL-6 and chemokine-related genes CXCL9, CXCL10, and CCL4 were significantly up-regulated. In conclusion, the fliL gene markedly influenced the pathogenicity of P. plecoglossicida infection in the hybrid groupers. Notably, deletion of fliL gene in P. plecoglossicida induced a robust immune response in the groupers, promoting defense against and elimination of pathogens via an inflammatory response involving multiple cytokines.

Animals↗

PubMed2026

The Small Noncoding RNA, RsaC, Is Essential for Staphylococcus aureus Virulence.

BACKGROUND: Bacterial small noncoding RNAs (sRNAs) play critical roles in virulence, stress adaptation, and host-pathogen interactions. Transcriptomic analyses during infection can help reveal pathogen-derived sRNAs required for pathogenesis, providing valuable insights for the development of novel therapeutic strategies. However, the low abundance of pathogen biomass within the host tissues poses a significant challenge for such analyses. METHODS: We employed 2-step cell disruption to enrich Staphylococcus aureus cells from infected mouse organs and conducted RNA sequencing (RNA-seq) analysis to examine staphylococcal sRNAs expressed during infection. qRT-PCR was used to confirm the gene expression. A knockout mutant of highly expressed sRNA, RsaC, was generated, and RNA-seq under in vivo as well as in vitro aerobic and anaerobic conditions were compared between the wild-type and ΔrsaC strains. Virulence of S. aureus was assessed using both mouse and silkworm survival assays. RESULTS: We identified RsaC as one of the most highly expressed sRNAs in mouse organs with consistent increment over time postinfection. Through gene disruption and complementation, we demonstrated that RsaC is an independent virulence determinant required for full pathogenicity of S. aureus in a murine infection model. In addition, RsaC influenced gene expression in response to oxygen availability and host-associated stress. Further analysis revealed that mutation of 2 genes downregulated in ΔrsaC in vivo, NWMN_RS03420 (sodium: proton antiporter) and NWMN_RS12015 (hypothetical protein), reduced S. aureus virulence in a silkworm model. CONCLUSIONS: These findings identify RsaC as a novel independent virulence determinant that supports S. aureus adaptation within the host.

Animals↗

PubMed2025

Hatching of whipworm eggs induced by bacterial contact is serine-protease dependent.

Whipworms (Trichuris spp) are ubiquitous parasites of humans and domestic and wild mammals that cause chronic disease, considerably impacting human and animal health. Egg hatching is a critical phase in the whipworm life cycle that marks the initiation of infection, with newly hatched larvae rapidly migrating to and invading host intestinal epithelial cells. Hatching is triggered by the host microbiota; however, the physical and chemical interactions between bacteria and whipworm eggs, as well as the bacterial and larval responses that result in the disintegration of the polar plug and larval eclosion, are not completely understood. Here, we examined hatching in the murine whipworm, Trichuris muris, and investigated the role of specific bacterial and larval structures and molecules in this process. Using scanning and transmission electron microscopy, we characterised the physical interactions of both fimbriated (Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa) and non-fimbriated (Staphylococcus aureus) bacteria with the egg polar plugs during the induction/initiation stage, and visualised the effects of structural changes in the polar plugs, leading to larval eclosion. Further, we found that protease inhibitors blocked whipworm hatching induced by both fimbriated and non-fimbriated bacteria in a dose-dependent manner, suggesting the partial involvement of bacterial enzymes in this process. In addition, we identified the minimal egg developmental timing required for whipworm hatching, and transcriptomic analysis of T. muris eggs through embryonation revealed the specific upregulation of serine proteases (S01A family) in fully embryonated eggs containing 'hatch-ready' L1 larvae. Finally, we demonstrated that inhibition of serine proteases with the serine-protease inhibitor Pefabloc ablated T. muris egg hatching induced by bacteria. Collectively, our findings unravel the temporal and physicochemical bacterial-egg interactions leading to whipworm hatching and indicate serine proteases of both bacterial and larval origin mediate these processes.

Animals↗

PubMed2026

Genome-wide transcriptional landscape of Mycobacterium tuberculosis during acute lung infection.

Tuberculosis (TB) remains a major global health burden, yet the mechanisms by which Mycobacterium tuberculosis (Mtb) adapts to host environments to drive disease pathology are incompletely defined. A key limitation has been reliance on axenic culture systems that fail to recapitulate the complex, host-imposed stresses encountered by Mtb in vivo. Here, we report the first microarray-based genome-wide transcriptomic profiling of Mtb in rabbit lungs with active TB, which closely mirrors human disease features, including granuloma heterogeneity, necrosis, and cavitation. Using Mtb RNA isolated from infected lung homogenates or broth-culture, we capture bacterial transcriptional states shaped by the host microenvironments. The transcriptional data analyses reveal extensive, context-dependent reprogramming of Mtb metabolic, respiratory, and stress-response networks that diverges markedly from in vitro expression profiles, including activation of stress adaptation, lipid catabolism, nucleic acid metabolism, and transcriptional regulation pathways. These data uncover pathways and networks that are selectively engaged in vivo and likely critical for Mtb survival within granulomatous lesions. Our findings demonstrate that transcriptional states most relevant to TB pathogenesis are underrepresented in standard lab-grown Mtb models and highlight the importance of in vivo bacterial profiling. By characterizing Mtb gene expression within diseased lungs, this study provides a systems-level framework for understanding TB pathogenesis and reveals in vivo-essential pathways, offering potential targets for translational drug discovery and the development of more effective anti-TB therapies.

Animals↗

PubMed2026

Genomic and transcriptomic characterization of genes expressed at 20 MPa by the marine actinobacterium Kocuria flava.

A marine hydrocarbonoclastic actinobacterium Kocuria flava IOS11 was isolated from 3500 m deep-sea water of the Indian Ocean. The isolate efficiently degraded phenanthrene (250 mg/L) achieving 82 and 98% of degradation at 0.1 MPa and 20 MPa, respectively within a period of 5 days. Whole genome, transcriptomee and metabolomic analysis elucidated its phenanthrene biodegradation efficiency under in situ deep-sea conditions. The genome sequence comprises 3.47 Mb distributed across 88 scaffolds with a high GC content of 74.30%. The genome analysis encoded 3126 genes including 3052 protein coding sequences with functional annotation identifying a broad array of genes associated with PAHs degradation, environmental stress adaptation, biosurfactant and siderophore synthesis. Transcriptome profiling under 0.1 and 20 MPa conditions with phenanthrene as a sole carbon source revealed enhanced expression of hydrocarbon degrading genes, transporters, biosurfactant associated enzymes and stress responsive genes including integrases, DNA repair protein Rad, alanine ligase, heat and cold shock proteins under high pressure conditions underscoring the deep-sea adaptation capabilities of the strain. The degradation pathway of phenanthrene was proposed through integrated genome, transcriptome and metabolomic analysis. These studies provided K. flava IOS11 as a metabolically versatile and pressure adapted bacterium with promising potential for bioremediation application in extreme marine environment.

Transcriptome↗

PubMed2024

Nonlethal deleterious mutation-induced stress accelerates bacterial aging.

Random mutagenesis, including when it leads to loss of gene function, is a key mechanism enabling microorganisms' long-term adaptation to new environments. However, loss-of-function mutations are often deleterious, triggering, in turn, cellular stress and complex homeostatic stress responses, called "allostasis," to promote cell survival. Here, we characterize the differential impacts of 65 nonlethal, deleterious single-gene deletions on Escherichia coli growth in three different growth environments. Further assessments of select mutants, namely, those bearing single adenosine triphosphate (ATP) synthase subunit deletions, reveal that mutants display reorganized transcriptome profiles that reflect both the environment and the specific gene deletion. We also find that ATP synthase α-subunit deleted (ΔatpA) cells exhibit elevated metabolic rates while having slower growth compared to wild-type (wt) E. coli cells. At the single-cell level, compared to wt cells, individual ΔatpA cells display near normal proliferation profiles but enter a postreplicative state earlier and exhibit a distinct senescence phenotype. These results highlight the complex interplay between genomic diversity, adaptation, and stress response and uncover an "aging cost" to individual bacterial cells for maintaining population-level resilience to environmental and genetic stress; they also suggest potential bacteriostatic antibiotic targets and -as select human genetic diseases display highly similar phenotypes, - a bacterial origin of some human diseases.

Escherichia coli↗

PubMed2026

Host-driven evolution shapes the polysaccharide utilization profiles of alga-associated Flavobacteriaceae.

BACKGROUND: Marine algae represent major producers of complex polysaccharides and serve as hosts for diverse microbial communities in the phycosphere. Flavobacteriaceae are among the key bacterial taxa involved in polysaccharide degradation and carbon remineralization in this environment. However, the extent to which algal hosts drive the divergence of polysaccharide utilization profiles in these bacteria remains unclear. RESULTS: We conducted a genome-resolved analysis of 103 cultured Flavobacteriaceae strains isolated from red, green, and brown macroalgae, as well as from diatoms and dinoflagellates. We found that macroalga-associated strains generally harbored more abundant and diverse CAZyme-encoding genes than their microalga-associated counterparts. Moreover, strains associated with different algal phyla showed distinct metabolic specializations that aligned with the typical polysaccharides of their respective hosts, strongly supporting host-specific adaptation. In four widely distributed genera (Maribacter, Flagellimonas, Polaribacter, Winogradskyella), CAZyme profile dissimilarity and key glycoside hydrolase gene divergence exhibited phylogenetic congruence with algal host phylogeny (Mantel r up to 0.76 and 0.85, respectively), indicative of host-associated functional adaptation. Using Maribacter as a model, cultivation experiments and transcriptome characterization demonstrated that polysaccharide utilization efficiency is not solely linked to the organization of genes into polysaccharide utilization loci (PULs), but also associated with the expression dynamics of key transcription factors (TFs), particularly those from AraC and DeoR families, whose expression patterns were coordinated with laminarin degradation. Notably, these two TF families also exhibited host-associated divergence patterns similar to those of CAZyme-encoding genes. Furthermore, analysis of the Tara Oceans metagenomic data indicated that, within the AraC and DeoR families, a higher proportion of genes were positively correlated with chlorophyll a content compared to other TF families, reinforcing their specialized roles in alga-associated bacterial lifestyles. CONCLUSIONS: Our integrative genomic and transcriptomic analyses reveal evolutionary and regulatory adaptation of marine Flavobacteriaceae to distinct algal hosts. These findings highlight algae-derived habitats as specialized niches that shape microbial metabolic potential, and suggest that carbohydrate metabolism plays a key role in host-driven bacterial evolution across global oceans. Video Abstract.

Flavobacteriaceae↗

PubMed2026

Intestinal blood vessel-associated macrophages and gut-vascular barrier dysfunction in cirrhosis.

BACKGROUND: Bacterial translocation in cirrhosis can trigger infection and hepatic decompensation, leading to systemic inflammation, organ failure and increased mortality. These infections often originate from the gastrointestinal tract after bacteria breach the intestinal barrier and disseminate to systemic sites. OBJECTIVE: In this study, we explore the mechanisms underlying intestinal barrier dysfunction in cirrhosis using an experimental cirrhosis model and patient-derived intestinal biopsies. DESIGN: We developed a murine model of cirrhosis through chronic administration of carbon tetrachloride for up to 20 weeks. We investigated both the intestinal epithelial and vascular compartments and performed single-cell transcriptomic profiling of myeloid cells isolated from cirrhotic mice and from individuals with compensated and decompensated cirrhosis. RESULTS: Our findings indicate that bacterial translocation in cirrhosis is the result of failure at multiple checkpoints, including aberrant epithelial cell death, vascular barrier damage and dysfunction of gut-vascular macrophages. In a preclinical model of cirrhosis, macrophages exhibited increased levels of monocyte-attracting chemokines, reduced bacterial clearance and impaired interactions with blood vessels. Importantly, depleting vascular-lining macrophages resulted in bacterial translocation to systemic sites, even in the absence of experimental liver disease. Transcriptional profiling of macrophages from duodenal biopsies of patients with cirrhosis indicated similar dysregulation of pathways supporting blood vessels and elevated expression of chemokines. CONCLUSIONS: This study emphasises the critical role of intestinal macrophages in preventing the dissemination of luminal bacteria and highlights the multifaceted breakdown of the intestinal barrier in cirrhosis and the importance of the gut-vascular barrier.

Animals↗

PubMed2026

Interaction analysis of miRNA and mRNA reveals the regulatory mechanism of immune response in golden pompano (Trachinotus ovatus) spleen to Streptococcus iniae infection.

Streptococcus iniae is a major warm-water pathogen that cause high mortality and severe economic losses in golden pompano industry. In the present study, we performed the mRNA-miRNA integrated transcriptomic analysis of spleen of golden pompano challenged with S. iniae to explore the possible regulatory mechanism to bacterial infection. In total, we excavated 5072 DEGs, of which 2765 up-regulated and 2307 down-regulated genes. KEGG enrichment analysis indicated that the DEGs were primarily enriched in immune-related pathways, such as proteasome, cytokine-cytokine receptor interaction, p53 signaling pathway, lysosome, phagosome, Herpes simplex virus 1 infection. Additionally, a protein-protein interaction (PPI) network was constructed to extract hub genes. And the result showed that 4 hub genes, comprising cd4, il10, tnfsf2, myd88, may play vital roles in response to S. iniae infection. Furthermore, a total of 46 differentially expressed miRNAs (DEMs) were identified, containing 23 known and 23 novel DEMs. By integrating mRNA and miRNA joint analysis, we established a miRNA-mRNA regulatory network, including 12 miRNAs and 14 genes. Among them, novel-miR-357 were identified as a multi-target hub miRNA. These results provide important insights into the molecular regulatory mechanisms of immune response and inflammation processes in the defense of golden pompano against S. iniae infection.

Integrative interaction↗

PubMed2025

Metagenomic and Transcriptomic Datasets of Plateau Brown Frogs (Rana kukunoris) from the Helan Mountains.

Global climate change has become a primary driving factor behind the biodiversity crisis in amphibians, making it crucial to understand how climate change affects species and their potential responses. The plateau brown frog (Rana kukunoris) is often regarded as an ideal ecological indicator species, yet research on its environmental adaptation mechanisms based on transcriptomic and microbiomic studies remains limited. Therefore, this study investigates the adaptation strategies of the plateau brown frog to environmental changes, providing extensive transcriptomic and the first comprehensive metagenomic dataset from two distinctly different environmental regions (eastern and western slopes of the Helan Mountains). We gathered transcriptomic data from three tissues (blood, liver, and muscle), resulting in 294,962 unigenes and 570,192 transcripts. Metagenomic sequencing identified major bacterial groups, including Firmicutes, Proteobacteria, Bacteroidetes, Spirochetes, and Actinobacteria. In summary, the results of this study can be used to further explore the associations among microbiota, host, and environment, which are crucial for comprehending the mechanisms of environmental adaptation in this species and contributing to the conservation of amphibian biodiversity.

Animals↗

PubMed2025

Dual RNA isolation from blood: an optimized protocol for host and bacterial RNA purification for dual RNA-sequencing analysis in whole blood sepsis samples.

Dual RNA-sequencing (dual RNA-seq) holds significant promise for deciphering bacterial virulence mechanisms during systemic infections. However, its application in sepsis research is hindered by technical challenges, including a low bacterial burden in blood and limited sample volumes and RNA yield from vulnerable populations, such as neonates. We developed an optimized protocol [dual RNA isolation from blood (DRIB)] for simultaneous stabilization, isolation and purification of high-quality host leukocyte and bacterial RNA from low-volume whole blood samples (0.5 ml). This protocol is compatible with clinical sample collection workflows and high-throughput RNA sequencing. The feasibility of DRIB for dual RNA-seq was validated using a pilot cohort of clinical adult sepsis samples, enabling the investigation of host-bacterial gene expression during sepsis. The DRIB protocol yielded 2.10-6.91 µg of total RNA per clinical sample in our pilot cohort. Dual-species ribosomal RNA (rRNA) depletion and RNA-seq generated 16.6-24.8 million filtered reads per sample, with 63±7% of reads uniquely mapped to host or bacterial sequences. Host genes accounted for 51-68% (8.4-10.9 million) reads, while 0.5-6.7% (79,496-789,808 reads) mapped to bacterial genomes. Bioinformatic analysis revealed that both shared and individual transcriptional patterns were identified in host and bacterial responses, including pathways related to immune metabolism and metal-ion binding. Our optimized DRIB protocol and RNA-seq pipeline effectively captured both host and bacterial RNA transcription in clinical sepsis samples. Expanding this approach to larger cohorts and varying disease timepoints will provide crucial new insights into host-bacterial gene co-expression dynamics in sepsis progression and outcomes.

Humans↗

PubMed2026

Ecr positively regulates activity of the PhoQ/PhoP signalling system in Klebsiella pneumoniae.

BACKGROUND: The rising prevalence of polymyxin resistance in multidrug-resistant Klebsiella pneumoniae presents a critical situation with limited therapeutic options. METHODS: Methods Genomic sequencing of 15 clinical polymyxin-resistant K. pneumoniae strains with multidrug resistance revealed that MgrB inactivation, predominantly disrupted by insertion sequences (ISs) in the IS1, IS4, and IS5 families, was the leading cause of polymyxin resistance. Comparative transcriptomics of wild-type, ΔmgrB, and ΔmgrBΔphoP were performed to elucidate the MgrB-PhoPQ regulatory network. RESULTS: This study conducted a system-wide analysis of the regulatory network and identified a species-specific PhoPQ regulon in K. pneumoniae.Beyond the classical MgrB-PhoPQ-ArnBCADTEF pathway, we identified a previously unannotated PhoPQ-regulated gene, 144 bp LN739_RS09850, encoding an Ecr homologue from Enterobacter cloacae. This protein has been reported to confer colistin heteroresistance, with the underlying mechanism not yet functionally validated. This study revealed that overexpression of Ecr homologues decreased colistin susceptibility in both K. pneumoniae and E. cloacae, but this phenotype was abolished upon phoP deletion, confirming PhoP's essential role. Consistent with this dependency, comparative transcriptomics of Ecr-overexpressing K. pneumoniae vs. control revealed significant upregulation of mgrB, phoPQ, arnBCADTE, and pmrD. Two-hybrid bacterial assays further demonstrated direct Ecr-PhoQ interaction. Electrophoretic mobility shift assay confirmed that PhoP directly binds to the ecr promoter in vitro, and a β-galactosidase reporter assay demonstrated that PhoP enhanced ecr promoter activity, indicating that PhoP regulates ecr expression by directly controlling its transcription. CONCLUSION: Collectively, these findings suggest that PhoP may directly activate the transcription of Ecr, with Ecr feedback activating the PhoPQ system via interaction with PhoQ, leading to induction of the arn operon and consequent polymyxin resistance.

Klebsiella pneumoniae↗

PubMed2024

From dysbiosis to homeostasis: Oleic acid matters in the vagina.

The role of fatty acids in shaping vaginal microbiota remains unclear. In an issue of Cell, Zhu et al. use genomic and transcriptomic analyses to reveal that oleic acid (OA) selectively inhibits L. iners while promoting L. crispatus, suggesting new strategies for the treatment of bacterial vaginosis (BV).

Female↗

PubMed2026

A conserved partner-switching system controls terminal differentiation in multicellular cyanobacteria.

UNLABELLED: Canonical partner-switching systems (PSSs) regulate sigma factor activity through reversible phosphorylation, but their established roles have been largely limited to stress responses and sporulation in Firmicutes. Whether this regulatory mechanism also controls developmental cell fate decisions in other bacterial phyla has remained unknown. Here, we identify a canonical PSS that governs heterocyst differentiation in the multicellular cyanobacterium Anabaena sp. PCC 7120. This system comprises the anti-sigma factor All2284 (NfsS) and the anti-anti-sigma factor All2283 (NfsR). Structural predictions and biochemical assays showed that NfsS phosphorylates NfsR on a conserved serine residue, whereas bacterial two-hybrid and co-purification assays demonstrated that NfsS binds the developmental sigma factors SigC and SigE. Deletion of nfsR abolished heterocyst formation and diazotrophic growth, and transcriptomic analysis revealed broad failure to induce late heterocyst genes, including nitrogen fixation functions such as nifHDK and fdxH. Phylum-wide comparative genomics further showed that PSS genes and putative functional clusters are strongly enriched in filamentous and heterocyst-forming taxa, indicating an association between the expansion of these signaling modules and the emergence of multicellularity and developmental specialization. Together, these findings establish a PSS as a direct regulator of terminal cell differentiation in a gram-negative bacterium and reveal partner switching as a conserved regulatory principle linking environmental signaling to developmental fate in a major bacterial phylum. IMPORTANCE: While partner-switching systems are classically associated with stress responses and sporulation control in Firmicutes, whether this regulatory logic governs developmental decisions in other bacterial phyla has remained unknown. Here, we establish that a related partner-switching mechanism operates in a distinct bacterial lineage, the cyanobacteria, where it controls a major developmental transition involving terminal cell differentiation. Specifically, we show that a phosphorylation-dependent checkpoint involving the anti-sigma factor NfsS and the anti-anti-sigma factor NfsR directly regulates heterocyst formation. Disruption of this switch abolishes cell differentiation and diazotrophic growth, revealing that this system is an obligate gatekeeper for terminal differentiation. Conceptually, these findings substantially extend the known functional repertoire of partner-switching circuits: rather than controlling stress adaptation or spore dormancy, this module has been co-opted to govern a complex, multicellular developmental program in an organism that underpins global carbon and nitrogen cycles. This work, therefore, establishes a new paradigm for phosphorylation-based control of developmental sigma factors and provides a tractable model for dissecting how conserved signaling modules are rewired to drive lineage-specific innovations across the bacterial domain.

cell differentiation↗

PubMed2026

Insights into the mechanism of enhanced tetramethylpyrazine production in dehulled adlay fermented by Bacillus subtilis BJ3-2.

Tetramethylpyrazine (TTMP) is a vital bioactive alkaloid and characteristic flavor compound in fermented foods. Our previous study found that fermentation of adlay by Bacillus subtilis BJ3-2 efficiently accumulates TTMP, whereas the underlying high-yield mechanism remains unclear. This study investigated the fermentation characteristics, gene transcription and protein expression of B. subtilis BJ3-2 in dehulled adlay (BDA) and soybean (BSB), respectively, and elucidated the mechanism responsible for high-yield TTMP production. The results showed that glutamate, leucine and phenylalanine were major free amino acids in BDA. The TTMP yield in BDA at 48 h (6.11 mg/g dry weight) was 360-fold higher than that in BSB. Transcriptomic and proteomic analysis demonstrated that compared with the soybean substrate, dehulled adlay substrate significantly up-regulated the expression of alsSD and ilvBH genes and their encoding proteins in B. subtilis BJ3-2, which were involved in C5-branched dibasic acid metabolism, 2-oxocarboxylic acid metabolism, and valine, leucine and isoleucine biosynthesis. Meanwhile, acetoin degradation was inhibited by down-regulating acetoin dehydrogenase complex (acoABCL) in citrate cycle, glycolysis/gluconeogenesis and carbon metabolism. Additionally, nitrogen metabolism pathway was transcriptionally enhanced to guarantee sufficient ammonium supply. Notably, protein-protein interaction and molecular docking analyses revealed that acetohydroxyacid synthase (ilvBH) interacted tightly with α-acetolactate decarboxylase (alsD), potentially forming a metabolic channel for acetoin synthesis. In conclusion, the efficient synthesis of TTMP in BDA was primarily attributed to the high synthesis and low degradation of acetoin, and the moderate synthesis of ammonium/ammonia. This study provided a theoretical basis for the targeted and efficient biosynthesis of TTMP.

Bacillus subtilis↗

PubMed2026

Airway microbiome diversity, intramucosal bacteria, and spatial immunity in asthmatic adults and controls.

RATIONALE: Asthma is characterized by disruption of the thoracic airway mucosae and loss of microbial diversity. Spatial profiling of the mucosal transcriptome may systematically discover mechanisms for microbial influences on immunity. OBJECTIVES: We investigated relationships between clinical measures, microbial communities, and the host mucosal transcriptome within different strata of bronchial biopsies in subjects with and without asthma. METHODS: We performed bronchoscopy in 65 asthmatic adults and 44 healthy controls, quantifying bacterial operational taxonomic units (OTUs) in bronchial brushings by 16S ribosomal RNA (rRNA) gene amplicon sequences. Biopsy histologic features were scored blind to diagnosis. Following 16S rRNA in situ hybridization of 44 biopsies, bacterial foci were scored in epithelium, basement membrane, and stroma. Global human gene expression was quantified in epithelial and stromal compartments using digital spatial profiling. MEASUREMENTS AND MAIN RESULTS: Clinical asthma was independently predicted by basement membrane abnormalities (BaseMA), endobronchial bacterial diversity, and circulating eosinophil counts, but not by specific OTU abundances. 16S rRNA staining revealed bacteria within epithelium and mucosa of all biopsies. Intramucosal bacteria counts correlated negatively with spatially organized coexpression networks encoding antigen-specific immunity, neutrophil functions, and matrix activation, whereas BaseMA correlated positively with the adaptive immunity module. Eosinophil counts correlated with epithelial bacterial counts and senescence pathways. Clinical asthma was accompanied by upregulation of a regulatory T-cell network. CONCLUSIONS: Asthma and its related phenotypes are accompanied by complex mucosal events that extend beyond eosinophilic pathways. Components of diverse airway microbiota may modify immunity by beneficial interactions within the mucosa.

Humans↗

PubMed2026

Optimized Hot Phenol-Based RNA Extraction from Mycobacteria: A Robust Approach for Reliable Gene Expression Analysis.

Mycobacterium tuberculosis (Mtb) remains a major global health threat, underscoring the need for reliable transcriptomic studies to understand its biology and drug resistance mechanisms. Such analyses depend on obtaining high-quality, high-yield RNA. Although several RNA extraction methods are available, many require expensive reagents, large culture volumes, or specialized equipment, limiting their suitability for large-scale studies, particularly in resource-constrained settings. Here, an optimized Hot Phenol based RNA extraction method specifically tailored for mycobacteria is presented. The method uses minimal culture volume and commonly available reagents to consistently yield high-quality RNA suitable for high-throughput transcriptomic applications. RNA quantity and integrity were assessed by gel electrophoresis and RNA integrity analysis (RIN), and its suitability for downstream applications was confirmed by qPCR and Qubit 4. To benchmark the performance of the optimized method, a parallel RNA extraction using TRIzol and RNeasy under identical experimental conditions was carried out, including the same Mycobacterium species, culture volume, growth phase (logarithmic and stationary), and lysis conditions. This allowed a direct comparison of yield, quality, feasibility, and cost. The optimized Hot Phenol method demonstrated comparable or improved RNA yield and quality while significantly reducing reagent cost and dependence on specialized equipment. Owing to its efficiency, reproducibility, and affordability, this protocol provides a practical alternative for large-scale gene expression and transcriptomic studies in Mtb and other mycobacterial species.

RNA, Bacterial↗

PubMed2025

Proteomic snapshot of pattern triggered immunity in the Arabidopsis leaf apoplast.

The apoplast is a critical interface in plant-pathogen interactions, particularly in the context of pattern-triggered immunity (PTI), which is initiated by recognition of microbe-associated molecular patterns. Our study characterizes the proteomic profile of the Arabidopsis apoplast during PTI induced by flg22, a 22-amino-acid bacterial flagellin epitope, to elucidate the output of PTI. Apoplastic washing fluid was extracted with minimal cytoplasmic contamination for liquid chromatography-tandem mass spectrometry analysis. By comparing our data to publicly available transcriptome profiles of flg22 treatment from 1 to 18 h, we observed that several highly abundant proteins exhibit relatively unchanged gene expression across all time points. We also observed topological bias in peptide recovery of 19 enriched receptor-like kinases with peptides predominantly recovered from their ectodomains. Notably, tetraspanin 8, an exosome marker, was enriched in PTI samples. We additionally confirmed increased concentrations of exosomes during PTI. This study enhances our understanding of the proteomic changes in the apoplast during plant immune responses and lays the groundwork for future investigations into the molecular mechanisms of plant defense under recognition of pathogen molecular patterns.

Arabidopsis↗