mSphere最新文献

{"title":"Nasal microbionts differentially colonize and elicit cytokines in human nasal epithelial organoids.","authors":"Andrea I Boyd, Leah A Kafer, Isabel F Escapa, Amal Kambal, Hira Tariq, Susan G Hilsenbeck, Hoa Nguyen-Phuc, Anubama Rajan, Joshua M Lensmire, Kathryn A Patras, Pedro A Piedra, Sarah E Blutt, Katherine P Lemon","doi":"10.1128/msphere.00493-25","DOIUrl":"10.1128/msphere.00493-25","url":null,"abstract":"<p><p>Nasal colonization by <i>Staphylococcus aureus</i> or <i>Streptococcus pneumoniae</i> is associated with an increased risk of infection by these pathobionts, whereas nasal colonization by <i>Dolosigranulum</i> species is associated with health. <u>H</u>uman <u>n</u>asal epithelial <u>o</u>rganoids (HNOs) differentiated at air-liquid interface (ALI) physiologically recapitulate human nasal respiratory epithelium with a robust mucociliary blanket. Due to their natural stem-like properties, HNO lines are a long-term experimental resource that offers genetic diversity based on the different donors. To develop HNOs as a new model system for bacterial nasal colonization, we reproducibly monocolonized HNOs differentiated at ALI with <i>S. aureus</i>, <i>S. pneumoniae</i>, or <i>Dolosigranulum pigrum</i> for up to 48 h with varying kinetics across species. HNOs tolerated bacterial monocolonization with localization of bacteria to the mucus layer and with minimal cytotoxicity compared to uncolonized HNOs. Human nasal epithelium exhibited both species-specific and general cytokine responses, without induction of type I interferons, which is consistent with colonization rather than infection. Only live <i>S. aureus</i> colonization robustly induced epithelial cell production of interleukin-1 family cytokines, suggestive of inflammasome signaling. <i>D. pigrum</i> and live <i>S. aureus</i> decreased CXCL10, whereas <i>S. pneumoniae</i> increased CXCL11, chemokines involved in antimicrobial responses to both viruses and bacteria. Overall, HNOs are a new model system for uncovering microbe-epithelial cell dynamics at the human nasal mucosa.</p><p><strong>Importance: </strong>Human nasal microbiota often includes highly pathogenic members, many of which are antimicrobial resistance threats, e.g., methicillin-resistant <i>Staphylococcus aureus</i> and drug-resistant <i>Streptococcus pneumoniae</i>. Preventing colonization by nasal pathobionts decreases infections and transmission. In contrast, nasal microbiome studies identify candidate beneficial bacteria that might resist pathobiont colonization, e.g., <i>Dolosigranulum pigrum</i>. Learning how these microbionts interact with the nasal epithelium and identifying new means to reduce pathobiont colonization are key goals in the field. As a tool to advance this research, we developed human nasal epithelial organoids (HNOs) differentiated at an air-liquid interface as a new model system of bacterial nasal colonization. HNOs accurately represent the mucosal surface of the human nasal passages, enabling exploration of bacterial-epithelial interactions, which is important since the epithelium is an instigator of the initial innate immune response to bacteria. Here, we identified differential epithelial cytokine responses to these three bacteria, setting the stage for future research.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0049325"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145192230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum for Schöpf et al., \"The antibacterial activity and therapeutic potential of the amphibian-derived peptide TB_KKG6K\".","authors":"Cristina Schöpf, Magdalena Knapp, Jakob Scheler, Débora C Coraça-Huber, Alessandra Romanelli, Peter Ladurner, Anna C Seybold, Ulrike Binder, Reinhard Würzner, Florentine Marx","doi":"10.1128/msphere.00469-25","DOIUrl":"10.1128/msphere.00469-25","url":null,"abstract":"","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0046925"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482140/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144855867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of temperature on microbial communities in bentonite for use in engineered barrier systems.","authors":"Rachel C Beaver, Cailyn M Perry, Chang Seok Kim, Josh D Neufeld","doi":"10.1128/msphere.00313-25","DOIUrl":"10.1128/msphere.00313-25","url":null,"abstract":"<p><p>Bentonite is an important component of deep geological repository (DGR) designs, where it will serve as a buffer between used fuel containers (UFCs) and subsurface rock walls of the repository. The potential for microbial activity in bentonite is being studied to understand the influence of microbial metabolisms (e.g., sulfate reduction by sulfate-reducing bacteria) on the long-term safety of the DGRs (e.g., through contributions to microbiologically influenced corrosion). Most studies of microorganisms in bentonite involved culturing microorganisms at 30°C or below, even though the placement room in a DGR is expected to experience elevated temperatures for up to one thousand years after used fuel placement. The purpose of this study was to test the abundance and community composition of microorganisms in as-received and hydrated bentonite at a range of DGR-relevant temperatures (15-105°C) using a combination of cultivation and DNA-based techniques. In certain clays tested, aerobic heterotrophs, anaerobic heterotrophs, and sulfate-reducing bacteria were culturable at 15, 30, 45, and 60°C from both the as-received and hydrated bentonite, demonstrating that the bentonite microbial community includes representatives capable of growth at a range of DGR-relevant temperatures. Although cultivation results showed no significant increase in the abundance of culturable microorganisms from as-received bentonite to hydrated bentonite at temperatures greater than 45°C, sequencing results for two bentonite samples hydrated and incubated at 60°C revealed that 16S rRNA gene profiles were dominated (>99%) by sequences associated with the putative thermophilic family Thermoactinomycetaceae, which was not detectable in the as-received bentonite starting material. Not only does this suggest that as-received bentonite harbours viable thermophiles, but it also highlights the importance of a multifaceted (e.g., cultivation coupled to DNA sequencing) approach to study microbial communities of bentonite.IMPORTANCEPredicting the abundances and types of microorganisms that may be active within a deep geological repository is critical to ensure that DGR design specifications minimize or prevent microbially mediated deterioration of DGR components. To date, research in this area has focused on the effect of bentonite dry density and the associated swelling pressure on suppression of microbial growth, but most of these experiments have been conducted at relatively low temperatures (e.g., 30°C). Studying the microbiology of bentonite exposed to elevated temperatures is critical given that a DGR is expected to experience high temperatures for up to one thousand years.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0031325"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482174/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144799733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unc-51-like kinase 1 (ULK1) regulates bacterial ubiquitylation and p62 recruitment during xenophagic clearance of <i>Listeria monocyt</i>ogenes.","authors":"J S Ribeiro, M S Siqueira, T S M Farias, T D P Spinasse, P L O Correia, R M Ribeiro, F M Bastos de Oliveira, L A M Carneiro, L H Travassos","doi":"10.1128/msphere.00308-25","DOIUrl":"10.1128/msphere.00308-25","url":null,"abstract":"<p><p>Autophagy is an essential cellular homeostatic process that also serves as an innate immune mechanism against intracellular bacterial pathogens through a highly selective form of autophagy known as xenophagy. Despite advances in understanding how bacteria are targeted for autophagic degradation, the specific regulatory mechanisms that drive the initial steps and ensure bacterial selection remain incompletely defined. Our study uncovers a pivotal role for Unc-51-like kinase 1 (ULK1) in the xenophagic clearance of the intracellular bacterial pathogen <i>Listeria monocytogenes</i>. We observed that ULK1 is essential for the efficient ubiquitylation of bacteria and subsequent recruitment of the autophagic adaptor protein p62 to the bacterial surface. Furthermore, we show that the impact of ULK1 deficiency in these early events-reduction in bacterial ubiquitylation, followed by impaired p62 targeting, results in diminished formation of bacteria-targeted autophagosomes. Notably, phosphorylation of p62 at the S409 residue, which is known to be dependent on ULK1 to enhance its affinity for ubiquitin, is necessary for the recruitment of p62 to the bacterial surface and adequate bacterial clearance, highlighting the regulatory role of ULK1 in this process. These findings unveil a previously unrecognized function of ULK1 in modulating early xenophagy steps, contributing to the autophagic control of intracellular pathogens. Our findings offer new perspectives into the manipulation of ULK1 activity for therapeutic interventions against infectious diseases.IMPORTANCEAutophagy is a vital process in eukaryotic cells that enables them to digest intracellular components, helping them respond to various stresses, including starvation, the accumulation of dysfunctional organelles, and infections. While the autophagic flux has been extensively studied over the past few decades, some key mechanisms remain poorly understood. Our research aimed to clarify one such mechanism: how the autophagic machinery specifically targets intracellular bacteria. We identified a novel role for the protein ULK1 in this process, demonstrating that ULK1 is essential for tagging bacteria with ubiquitin within the cell and recruiting the protein p62. These are critical steps for adequate bacterial clearance. Our results underscore the pivotal role of ULK1 in initiating the cellular defense against bacterial infections. Our findings could pave the way for new therapeutic strategies to enhance the body's capacity to combat bacterial infections.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0030825"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482158/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144962349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of sporogeny in the malaria transmission-blocking symbiont of <i>Anopheles</i> mosquitoes.","authors":"Jeremy K Herren","doi":"10.1128/msphere.00325-25","DOIUrl":"10.1128/msphere.00325-25","url":null,"abstract":"<p><p>In recent work, Parry et al. provide a detailed visualization of <i>Microsporidia</i> MB sporogeny (E. R. S. Parry, R. Pevsner, B. C. Poulton, D.-K. Purusothaman, et al., mSphere 10:e00851-24, 2025, https://doi.org/10.1128/msphere.00851-24). Their findings reveal that <i>Microsporidia</i> MB is localized to mosquito germline tissues and undergoes octosporogony within developing oocytes, suggesting both vertical and potential horizontal transmission routes. The identification of spores with hallmark microsporidian structures strengthens the case for environmental dissemination via egg deposition. These results fill key biological knowledge gaps and set new methodological standards for <i>in vivo</i> symbiont imaging. This work advances <i>Microsporidia</i> MB's feasibility as a transmission-blocking symbiont and supports its development as a novel, sustainable malaria control tool.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0032525"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482168/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144855866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthetic communities of maize root bacteria interact and redirect benzoxazinoid metabolization.","authors":"Lisa Thoenen, Christine Pestalozzi, Tobias Zuest, Marco Kreuzer, Pierre Mateo, Mikiko Karasawa, Gabriel Deslandes, Christelle A M Robert, Rémy Bruggmann, Matthias Erb, Klaus Schlaeppi","doi":"10.1128/msphere.00159-25","DOIUrl":"10.1128/msphere.00159-25","url":null,"abstract":"<p><p>Plant roots are colonized by diverse microbial communities. These communities are shaped by root exudates, including plant-specialized metabolites. Benzoxazinoids are such secreted compounds of maize. Individual microbes differ in their ability to tolerate and metabolize antimicrobial benzoxazinoids. To investigate how these traits combine in a community, we designed two synthetic communities of maize root bacteria that share six common strains and differ in their ability to metabolize benzoxazinoids based on the seventh strain. We exposed both communities to the benzoxazinoid MBOA (6-methoxybenzoxazolin-2(3H)-one) <i>in vitro</i> and found that the metabolizing community did not degrade MBOA to its aminophenoxazinone, as observed for individual strains, but, as a community, they formed the corresponding acetamide. MBOA shaped the differential compositions of both communities and increased the fraction of MBOA-tolerant strains. The benzoxazinoid-metabolizing community showed a higher tolerance to MBOA and was able to utilize MBOA as their sole carbon source for growth. Hence, bacterial interaction results in alternative benzoxazinoid metabolization and increases community performance in the presence of these antimicrobial compounds. Future work is needed to uncover the genetics of this metabolic interaction and ecological consequences for the bacterial community and the host plant.IMPORTANCEWe investigated how maize root bacteria-alone or in community-tolerate and metabolize antimicrobial compounds of their host plant. We found that the capacity to metabolize such a compound impacts bacterial community size and structure and, most importantly, benefits community fitness. We also found that interacting bacteria redirected the metabolization of the antimicrobial compound to an alternative degradation pathway. Our work highlights the need to study the teamwork of microbes to uncover their community traits to ultimately understand the ecological consequences for the bacterial community and eventually the host plant.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0015925"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12483121/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144961650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative characterization of bronchial and nasal mucus reveals key determinants of influenza A virus inhibition.","authors":"Marie O Pohl, Kalliopi Violaki, Lu Liu, Elisabeth Gaggioli, Irina Glas, Josephine von Kempis, Carina Messerli, Chia-Wei Lin, Céline Terrettaz, Shannon C David, Frank W Charlton, Ghislain Motos, Nir Bluvshtein, Aline Schaub, Liviana K Klein, Beiping Luo, Nicole C Leemann, Markus Ammann, Walter Hugentobler, Ulrich K Krieger, Thomas Peter, Tamar Kohn, Athanasios Nenes, Silke Stertz","doi":"10.1128/msphere.00365-25","DOIUrl":"10.1128/msphere.00365-25","url":null,"abstract":"<p><p>Differentiated primary human respiratory epithelial cells grown at air-liquid interface have become a widely used cell culture model of the human conducting airways. These cultures contain secretory cells such as goblet and club cells, which produce and secrete mucus. Here, we characterize the composition of mucus harvested from airway cultures of nasal and bronchial origin. We find that despite inter-donor variability, the salt, sugar, lipid, and protein content and composition are very similar between nasal and bronchial mucus. However, subtle differences in the abundance of individual components in nasal versus bronchial mucus can influence its antimicrobial properties. The ability of mucus to neutralize influenza A virus varies with the anatomical origin of the airway cultures and correlates with the abundance of triglycerides and specific sialylated glycoproteins and glycolipids.IMPORTANCERespiratory mucus plays an important role during the transmission and infection process of microbes in the human respiratory tract. In the case of influenza A virus, the mucus stabilizes the virions in infectious respiratory particles and droplets but hampers virus particles before they reach the respiratory epithelium through its physicochemical properties and the presence of sialylated decoy receptors. However, it is thus far not well understood which components of mucus mediate protection and inhibition. Our study now provides a comprehensive analysis of bronchial and nasal mucus from primary human airway cultures that can be used as a resource for future experimental designs and interpretations.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0036525"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482186/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144962304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using BONCAT to dissect the proteome of <i>S. aureus</i> persisters.","authors":"Eva D C George Matlalcuatzi, Thomas Bakkum, Pooja S Thomas, Stephan Hacker, Bogdan I Florea, Bastienne Vriesendorp, Daniel E Rozen, Sander I van Kasteren","doi":"10.1128/msphere.00431-25","DOIUrl":"10.1128/msphere.00431-25","url":null,"abstract":"<p><p>Bacterial persisters are a subpopulation of cells that exhibit a transient non-susceptible phenotype in the presence of bactericidal antibiotic concentrations. This phenotype can lead to the survival and regrowth of bacteria after treatment, resulting in relapse of infections. It is also a contributing factor to antibacterial resistance. Multiple processes are believed to cause persister formation; however, identifying the proteins expressed during the induction of persistence is challenging because the persister state is rare, transient, and does not result in genetic changes. In this study, we used Bio-Orthogonal Non-Canonical Amino Acid Tagging (BONCAT) to label and retrieve the proteome expressed during persistence and recovery for two strains of <i>Staphylococcus aureus</i> exposed to β-lactam and fluoroquinolone antibiotics. After incubating antibiotic-exposed bacteria with the methionine ortholog L-azidohomoalanine to label the proteins of persister cells, we retrieved labeled proteins using click chemistry-pulldown methodology. Analysis of the retrieved proteome of persisters with Label-Free Quantification-Liquid chromatography mass spectrometry (LFQ-LCMS)-based proteomics revealed widespread changes in translation. Our analysis uncovered previously identified persister genes, including, for example, <i>relA/spot</i>-system, changes in purine and amino acid metabolism, the upregulation and downregulation of transcription factors, and changes to influx and efflux pumps, thus validating our methodology. In addition, we also identified numerous novel persister-associated proteins. Few changes were conserved across the two strains and both antibiotics. Instead, results suggest that the mechanisms of persister formation vary across genotypes and the drugs to which strains are exposed. These findings provide evidence that the entry into persistence is an active process that dramatically alters the translational behavior of cells and suggest that downregulation of metabolism, by diverse but functionally similar processes, in persister cells enables cells to survive antibiotic pressure.IMPORTANCEIn this study, we have applied a technique called \"Bioorthogonal Non-Canonical Amino Acid-Tagging,\" or BONCAT, to identify which proteins are expressed when bacteria are in the persister state. Our work makes novel contributions to our understanding of persister cells, a bacterial sub-population that gives rise to recurrent infections, and establishes BONCAT as a valuable tool to study phenotypic heterogeneity in bacterial populations.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0043125"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482189/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145015818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of polyamine resistance in <i>Staphylococcus aureus</i> through modulation of potassium transport.","authors":"Killian Campbell, Caitlin H Kowalski, Kristin M Kohler, Mara R Kebret, Matthew F Barber","doi":"10.1128/msphere.00613-24","DOIUrl":"10.1128/msphere.00613-24","url":null,"abstract":"<p><p>Microbes must adapt to diverse biotic and abiotic factors encountered in host environments. Polyamines are an abundant class of aliphatic molecules that play essential roles in fundamental cellular processes across the tree of life. Surprisingly, the bacterial pathogen <i>Staphylococcus aureus</i> is highly sensitive to polyamines encountered during infection, and acquisition of a polyamine resistance locus has been implicated in the spread of the prominent USA300 methicillin-resistant <i>S. aureus</i> lineage. At present, alternative pathways of polyamine resistance in staphylococci are largely unknown. Here, we applied experimental evolution to identify novel mechanisms and consequences of <i>S. aureus</i> adaptation when exposed to increasing concentrations of the polyamine spermine. Evolved populations of <i>S. aureus</i> exhibited striking evidence of parallel adaptation, accumulating independent mutations in the potassium transporter genes <i>ktrA</i> and <i>ktrD</i>. Mutations in either <i>ktrA</i> or <i>ktrD</i> are sufficient to confer polyamine resistance and function in an additive manner. Moreover, we find that <i>ktr</i> mutations provide protection against multiple classes of unrelated cationic antibiotics, suggesting a common mechanism of resistance. Consistent with this hypothesis, ktr mutants exhibit alterations in cell surface charge indicative of reduced affinity and uptake of cationic molecules. Finally, we observe that laboratory-evolved <i>ktr</i> mutations are also present in diverse natural <i>S. aureus</i> isolates, suggesting these mutations contribute to antimicrobial resistance during human infections. Collectively, this study identifies a new role for the <i>S. aureus</i> potassium transport system in resistance to both host-derived and clinically used antimicrobials.</p><p><strong>Importance: </strong><i>Staphylococcus aureus</i> is a leading cause of infectious disease-related deaths globally. Understanding factors that govern adaptation and survival of <i>S. aureus</i> and other pathogens in the host environment is critical for improving infection outcomes. It has been known for several years that <i>S. aureus</i> is highly sensitive to polyamines, a broadly produced class of molecules that play important cellular functions across bacteria and eukaryotes. How <i>S. aureus</i> is capable of adapting to polyamine toxicity remains largely mysterious. Using experimental evolution, our study reveals that changes in potassium transport are sufficient to confer high-level polyamine resistance in <i>S. aureus</i> while simultaneously increasing resistance to unrelated classes of clinically used antibiotics. Our results identify new roles for bacterial potassium transport in polyamine resistance as well as highlighting the utility of experimental evolution for identifying new genetic determinants of pathogen adaptation.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0061324"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482181/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144874236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kre6-dependent β-1,6-glucan biosynthesis only occurs in the conidium of <i>Aspergillus fumigatus</i>.","authors":"Kalpana Singh, Christine Henry, Isabelle Mouyna, Anne Beauvais, Yifan Xu, Aswath Karai, Norman van Rhijn, Jean-Paul Latgé, Tuo Wang","doi":"10.1128/msphere.00341-25","DOIUrl":"10.1128/msphere.00341-25","url":null,"abstract":"<p><p>The structural role of β-1,6-glucan has remained under-investigated in filamentous fungi compared to other fungal cell wall polymers, and previous studies have shown that the cell wall of the mycelium of <i>A. fumigatus</i> did not contain β-1,6-glucans. In contrast, the current solid-state NMR investigations showed that the conidial cell wall contained a low amount of β-1,6-glucan. ssNMR comparisons of the <i>A. fumigatus</i> and <i>C. albicans</i> β-1,6-glucans showed they are structurally similar. The deletion of the <i>KRE6</i> gene which is the only <i>KRE</i> gene in the <i>A. fumigatus</i> genome resulted in a mutant depleted of β-1,6-glucan which has a growth phenotype similar to the parental strain. Even though it is not an essential polymer in <i>A. fumigatus</i>, β-1,6-glucan plays a role in cell wall organization since the <i>kre6</i>Δ mutant showed a higher sensitivity to Congo-red and Calcofluor white which are known to be general cell wall inhibitors. It is also another example of the significant structural differences seen between conidium and mycelium of filamentous fungi.IMPORTANCEThis study shows for the first time that β-1,6-glucans are found in <i>Aspergillus fumigatus</i>. Interestingly, this polysaccharide was specifically identified in conidia.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0034125"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12482176/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145015895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}