mSphere最新文献

{"title":"The pan-variant potential of light: 425 nm light inactivates SARS-CoV-2 variants of concern and non-cytotoxic doses reduce viral titers in human airway epithelial cells.","authors":"Nathan Stasko, Leslee Arwood, Nicole Jandick, Derry Spragion, Rachel C Roberts, Mónica Setién, Ibrahim Henson, Abigail Annas, M Leslie Fulcher, Marisa Brotton, Larry Kummer, Frank Szaba, Matt Reagan, Kathleen Lanzer, Tres Cookenham, Sean Casey, Nagarama Kothapalli, Tricia Hart, Shelton S Bradrick, David Emerson, Adam S Cockrell, Scott H Randell, Jacob F Kocher","doi":"10.1128/msphere.00230-25","DOIUrl":"10.1128/msphere.00230-25","url":null,"abstract":"<p><p>Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) prolonged the coronavirus disease 2019 (COVID-19) pandemic. The continued development of novel pan-variant therapeutics to treat currently circulating and future VOCs is critically important. Photomedicine may offer broadly applicable, pan-variant treatments. In this study, we show that visible light centered around 425 nm inactivates each of the five SARS-CoV-2 VOC lineages that have been identified by the World Health Organization (Alpha, Beta, Delta, Gamma, and Omicron) in cell-free suspensions in a dose-dependent manner, including bamlanivimab-resistant variants. Specifically, 60 J/cm² of 425 nm light reduced SARS-CoV-2 titers by >4 log₁₀ relative to unilluminated controls. We observed that 425 nm light inactivates SARS-CoV-2 through restricted entry to host cells. In addition, a non-cytotoxic dosing regimen of 32 J/cm² of 425 nm light reduced infectious virus titers in well-differentiated air-liquid interface (ALI) human airway epithelial (HAE) cells infected with the Beta, Delta, and Omicron variants that incorporate mutations associated with immune evasion and/or increased transmissibility. Infectious SARS-CoV-2 titers were reduced when dosing began during the early stages of infection or in more established infections. Finally, we translated these findings to the RD-X19, a novel medical device that emits 425 nm light; our results showed that the RD-X19 restricted spike binding to ACE-2 and reduced SARS-CoV-2 titers in cell-free suspensions (by >2 log₁₀) and in the ALI HAE model (by >1 log₁₀). These findings indicate that photomedicine utilizing 425 nm visible light may serve as a novel, pan-variant treatment modality for COVID-19.<b>IMPORTANCE</b>The continued spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the emergence of variants that can evade public health measures, including vaccines and therapeutics. Thus, the continued development of broadly applicable measures to supplement current public health measures and standards of care remains critical. Photomedicine is one such approach. In this study, we show that non-ultraviolet visible light can inactivate each SARS-CoV-2 variant of concern (VOC) by preventing entry to host cells. Furthermore, visible light reduced the amount of virus produced in an infection model of the human airway at multiple stages of infection, demonstrating the antiviral capability of visible light. This study provides preclinical support for the development of visible light to serve as a SARS-CoV-2 countermeasure and warrants further investigation.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0023025"},"PeriodicalIF":3.7,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12188739/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144160693","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":"The pre-mRNA splicing modulator pladienolide B inhibits <i>Cryptococcus neoformans</i> germination and growth.","authors":"Sierra L Love, Megan C McKeon, Henrik Vollmer, Joshua C Paulson, Nanami Oshimura, Olivia Valentine, Sébastien C Ortiz, Christina M Hull, Aaron A Hoskins","doi":"10.1128/msphere.00248-25","DOIUrl":"https://doi.org/10.1128/msphere.00248-25","url":null,"abstract":"<p><p><i>Cryptococcus neoformans</i> is an opportunistic fungal pathogen responsible for life-threatening infections, particularly in immunocompromised individuals. The limitations of current antifungal therapies due to toxicity and the emergence of resistance highlight the need for novel treatment strategies and targets. <i>C. neoformans</i> has an intron-rich genome, and pre-mRNA splicing is required for expression of the vast majority of its genes. In this study, we investigated the efficacy of a human splicing inhibitor, pladienolide B (PladB), as an antifungal against <i>C. neoformans</i>. PladB inhibited the growth of <i>C. neoformans</i> in liquid culture and spore germination. The potency of PladB could be increased by simultaneous treatment with either FK506 or clorgyline. This combination treatment resulted in significant reductions in fungal growth and prevented spore germination. Transcriptomic analysis revealed that PladB inhibits splicing in <i>C. neoformans</i> and results in widespread intron retention. In combination with FK506, this resulted in downregulation of or intron retention in transcripts from processes vital for cellular growth, including translation, transcription, and RNA processing. Together, these results suggest that targeting RNA splicing pathways could be a promising antifungal strategy and that the effectiveness of splicing inhibitors as antifungals can be increased by co-administering drugs such as FK506.IMPORTANCEFungal infections, like those caused by <i>Cryptococcus neoformans</i>, can turn deadly for many patients. New treatments and therapeutic targets are needed to combat these pathogens. One potential target is the pre-mRNA processing pathway, which is required for expression of nearly all protein-coding genes in <i>C. neoformans</i>. We have determined that a pre-mRNA splicing inhibitor can inhibit both <i>C. neoformans</i> growth and germination and that the potency of this drug can be increased when used in combination with other molecules. This work provides evidence that targeting steps in pre-mRNA processing may be an effective antifungal strategy and avenue for the development of new medicines.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0024825"},"PeriodicalIF":3.7,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144476112","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":"Refinement of the Reference Viral Database (RVDB) for improving bioinformatics analysis of virus detection by high-throughput sequencing (HTS).","authors":"Pei-Ju Chin, Jaysheel D Bhavsar, Trent J Bosma, Madolyn L MacDonald, Shawn W Polson, Arifa S Khan","doi":"10.1128/msphere.00286-25","DOIUrl":"https://doi.org/10.1128/msphere.00286-25","url":null,"abstract":"<p><p>All biological products are required to demonstrate the absence of adventitious viruses (AVs), which may be inadvertently introduced at different steps involved in the manufacturing process. The currently recommended <i>in vitro</i> and <i>in vivo</i> virus detection assays have limitations for broad detection and are lengthy and laborious. Additionally, the use of animals is discouraged by the global 3 R's initiative for replacement, reduction, and refinement. High-throughput or next-generation sequencing (HTS/NGS) technologies can rapidly detect known and novel viruses in biological materials. There are, however, challenges for HTS detection of AVs due to differential abundance of viral sequences in public databases, which led to the creation of a non-redundant, Reference Viral Database (RVDB) containing all viral, viral-like, and viral-related sequences, with a reduced cellular sequence content. In this paper, we describe improvements in RVDB, which include the transition of RVDB production scripts from the original Python 2 to Python 3 codebase, updating the semantic pipeline to remove misannotated non-viral sequences and irrelevant viral sequences, use of taxonomy for the removal of phages, and inclusion of a quality-check step for SARS-CoV-2 genomes to exclude low-quality sequences. Additionally, RVDB website updates include search tools for exploring the database sequences and implementation of an automatic pipeline for providing annotation information to distinguish non-viral and viral sequences in the database. These updates for refining RVDB are expected to enhance HTS bioinformatics by reducing the computational time and increasing the accuracy for virus detection.IMPORTANCEHigh-throughput sequencing (HTS) has emerged as an advanced technology for demonstrating the safety of biological products. HTS can be used as an alternative adventitious virus detection method for replacing the currently recommended <i>in vivo</i> and PCR assays and supplementing or replacing the <i>in vitro</i> cell culture assays. However, HTS bioinformatics analysis for broad virus detection, including both known and novel viruses, depends on using a comprehensive and accurately annotated database. In this study, we have refined our original comprehensive Reference Virus Database (RVDB) for greater accuracy of virus detection with a reduced computational burden. Additionally, the production script for automating the generation of RVDB was updated to facilitate reliable database production and timely availability.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0028625"},"PeriodicalIF":3.7,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144476111","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":"Quorum sensing modulates microbial community structure through regulation of secondary metabolites.","authors":"April C Armes, Amy L Schaefer, Leah H Hochanadel, Dawn M Klingeman, Dana L Carper, Paul E Abraham, Larry M York, Alyssa A Carrell, Mitchel J Doktycz, Dale A Pelletier","doi":"10.1128/msphere.01050-24","DOIUrl":"10.1128/msphere.01050-24","url":null,"abstract":"<p><p>Bacteria are recognized for their diverse metabolic capabilities, yet the impact of microbe-microbe interactions on multispecies community structure and dynamics is poorly understood. Cell-to-cell signaling in the form of quorum sensing (QS) often regulates secondary metabolite production and microbial interactions. Here, we examine how acylhomoserine lactone (AHL)-mediated QS impacts microbial community structure in a 10-member synthetic community of isolates from <i>Populus deltoides</i>. To explore the role of QS in microbial community structure and dynamics, we disrupted AHL signaling by exogenous addition of AiiA-lactonase, an enzyme that cleaves the lactone ring. Microbial community structure resulting from signal inactivation, as measured by 16S rRNA amplicon sequencing and secondary metabolite production, was assessed after successive passaging of the community. Further, we investigated the impact of quorum quenching on specific microbe-microbe interactions using pairwise inhibition assays. Our results indicate that AHL inactivation alters the relative abundance of dominant community members at later passages but does not impact the overall membership in the community. Quorum quenching significantly alters the metabolic profile in lactonase-treated communities. This metabolic alteration impacts microbe-microbe interactions through decreased inhibition of other community members. Together, these results indicate that QS impacts microbial community structure through the regulation of secondary metabolites in dominant members and that the membership of microbial communities can be relatively stable despite changes in metabolic profiles.IMPORTANCEIn terrestrial ecosystems, bacteria exist as multispecies consortia and provide diverse ecosystem services. Interactions among microbes contribute to determining their abundance and population structure and are often mediated by cell-to-cell communication. However, the role of microbial communication in community assembly is poorly understood. In this study, we investigated the disruption of AHL-based quorum sensing on bacterial community structure using a synthetic microbial community derived from a plant host. We found that disrupting AHL signaling did not change the membership but shifted the relative abundance of the dominant community members. Metabolic profiles of disrupted communities reveal alterations in key secondary metabolites that likely reduce antagonistic behavior. Investigating the driving mechanisms underlying microbial community assembly is fundamental to understanding microbial ecosystem ecology and can be broadly applied toward understanding sustainable systems and facilitating agricultural applications where plant-associated microbes are of growing importance.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0105024"},"PeriodicalIF":3.7,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144333543","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":"NLP-like deep learning aided in identification and validation of thiosulfinate tolerance clusters in diverse bacteria.","authors":"Brendon K Myers, Anuj Lamichhane, Brian H Kvitko, Bhabesh Dutta","doi":"10.1128/msphere.00023-25","DOIUrl":"https://doi.org/10.1128/msphere.00023-25","url":null,"abstract":"<p><p>Allicin tolerance (<i>alt</i>) clusters in phytopathogenic bacteria, which provide resistance to thiosulfinates like allicin, are challenging to find using conventional approaches due to their varied architecture and the paradox of being vertically maintained within genera despite likely being horizontally transferred. This results in significant sequential diversity that further complicates their identification. Natural language processing (NLP), like techniques such as those used in DeepBGC, offers a promising solution by treating gene clusters like a language, allowing for identifying and collecting gene clusters based on patterns and relationships within the sequences. We curated and validated <i>alt</i>-like clusters in <i>Pantoea ananatis</i> 97-1R, <i>Burkholderia gladioli</i> pv. <i>gladioli</i> FDAARGOS 389, and <i>Pseudomonas syringae</i> pv. tomato DC3000. Leveraging sequences from the RefSeq bacterial database, we conducted comparative analyses of gene synteny, gene/protein sequences, protein structures, and predicted protein interactions. This approach enabled the discovery of several novel <i>alt</i>-like clusters previously undetectable by other methods, which were further validated experimentally. Our work highlights the effectiveness of NLP-like techniques for identifying underrepresented gene clusters and expands our understanding of the diversity and utility of <i>alt</i>-like clusters in diverse bacterial genera. This work demonstrates the potential of these techniques to simplify the identification process and enhance the applicability of biological data in real-world scenarios.IMPORTANCEThiosulfinates, like allicin, are potent antifeedants and antimicrobials produced by <i>Allium</i> species and pose a challenge for phytopathogenic bacteria. Phytopathogenic bacteria have been shown to utilize an allicin tolerance (<i>alt</i>) gene cluster to circumvent this host response, leading to economically significant yield losses. Due to the complexity of mining these clusters, we applied techniques akin to natural language processing to analyze Pfam domains and gene proximity. This approach led to the identification of novel <i>alt</i>-like gene clusters, showcasing the potential of artificial intelligence to reveal elusive and underrepresented genetic clusters and enhance our understanding of their diversity and role across various bacterial genera.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0002325"},"PeriodicalIF":3.7,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144317517","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":"The ionophore resistance genes <i>narA</i> and <i>narB</i> are geographically widespread and linked to resistance to medically important antibiotics.","authors":"Asalia Ibrahim, Jason Au, Alex Wong","doi":"10.1128/msphere.00243-25","DOIUrl":"https://doi.org/10.1128/msphere.00243-25","url":null,"abstract":"<p><p>Ionophores are a class of antibiotics used widely in animal production as anti-coccidials and for growth promotion. Since ionophores are not used in human medicine, it has largely been assumed that they do not contribute to medically important antimicrobial resistance (AMR). Nonetheless, there is increasing concern that ionophore usage could co-select for clinically relevant AMR, since the ionophore resistance genes <i>narA</i> and <i>narB</i> have been found in linkage with multiple AMR genes. We investigated the global distribution and AMR linkage of <i>narA</i> and <i>narB</i> using publicly available data. These ionophore resistance genes can be found worldwide, with >2,400 <i>narAB</i>-bearing isolates reported from 51 countries. Isolates were derived from a range of host species, including poultry, cattle, and humans. <i>narAB</i> was linked with an average of over 10 resistance determinants for AMR, including many medically important antibiotics. These observations indicate that we cannot assume that ionophore use is risk-free, with clear potential for co-selection for clinically relevant AMR.IMPORTANCEIonophores are a type of antibiotic used to promote growth in cattle and pigs and to treat parasitic infections in poultry. It has been assumed that ionophore use in animals does not pose a risk for humans. However, growing evidence suggests that ionophore use may select for medically relevant antibiotic resistance. Using analyses of public data, we found that ionophore resistance is widespread and that it is usually linked to resistance genes for medically relevant drugs. There is thus clear potential for ionophore use to impact the presence of antibiotic resistance genes in the food supply.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0024325"},"PeriodicalIF":3.7,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144317518","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":"The development of functional opsonophagocytic assays to evaluate antibody responses to <i>Klebsiella pneumoniae</i> capsular antigens.","authors":"Robert Lawrence, Emma Bownes, Marina Johnson, Heather Fox, Drew Huff, Ivan Olave, Anup Datta, David Goldblatt, Nathalie Karaky","doi":"10.1128/msphere.00176-25","DOIUrl":"https://doi.org/10.1128/msphere.00176-25","url":null,"abstract":"<p><p><i>Klebsiella pneumoniae</i> is one of the leading causes of nosocomial infections in low- and middle-income countries (LMICs), with a high mortality rate among the immunocompromised. With increasing antibiotic resistance, there is an urgent need for preventive measures such as vaccines, but none are currently licensed for use. In order to evaluate natural immunity and assess the immunogenicity of novel vaccines, we set out to develop functional assays that effectively measure the immune response of <i>K. pneumoniae</i> anti-capsular antibodies <i>in vitro</i>. Serotypes KL2, KL15, KL25, KL62, and KL102 were targeted as these are five of the most prevalent and invasive strains, particularly in LMIC settings, and are putative vaccine antigens. Opsonophagocytic killing assays (OPAs) for each serotype were developed and qualified. Serotype-specific IgG from vaccinated rabbit sera and human sera was used to demonstrate <i>in vitro</i> antibody and complement-mediated killing for all serotypes tested, whereas cross-reactivity between each serotype was minimal by competitive analyses. These assays act as a platform to allow further serological evaluation of natural immunity and the performance of <i>K. pneumoniae</i> vaccines. Understanding the function of vaccine-induced antibodies, as well as natural IgG induced by exposure to <i>K. pneumoniae</i>, will be crucial to determine correlates of protection and aid in the path to licensure of a <i>K. pneumoniae</i> vaccine.IMPORTANCE<i>K. pneumoniae</i> is a pathogen that causes serious infections such as pneumonia and sepsis globally. The increasing prevalence of antibiotic resistance in this pathogen has complicated treatment efforts, highlighting the need for preventive therapeutic strategies such as vaccination. However, no licensed vaccines are currently available. Standardized assays to assess the immunogenicity of new vaccines are crucial for vaccine development and evaluation of other therapeutics. Therefore, we have developed assays that can assess the functionality of antibodies, which can be used to evaluate the potential of novel <i>K. pneumoniae</i> conjugate vaccines, and inform which antibodies are most effective for preventing disease.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0017625"},"PeriodicalIF":3.7,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144275405","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":"Control of citrate utilization by <i>Candida albicans</i> Adr1.","authors":"Amelia M White, Aaron P Mitchell","doi":"10.1128/msphere.00311-25","DOIUrl":"https://doi.org/10.1128/msphere.00311-25","url":null,"abstract":"<p><p><i>Candida albicans</i>, a fungal commensal and pathogen, occupies diverse niches in the human host. Its broad metabolic repertoire is critical for its survival. The model yeast <i>Saccharomyces cerevisiae</i> provides a starting point for analysis of <i>C. albicans</i> physiology and regulatory circuitry, but there are many examples of rewired transcription factors that govern different processes in the two organisms. We focus here on Adr1, which in <i>S. cerevisiae</i> promotes alternative carbon source utilization and in <i>C. albicans</i> promotes ergosterol synthesis. We find that <i>C. albicans</i> Adr1 is also required for growth on citrate and compounds that feed into the citric acid cycle, like glutamate and malate. RNA-sequencing (RNA-seq) shows that predicted citrate metabolic genes, representing both the citric acid cycle and gluconeogenesis, are downregulated in an <i>adr1</i>Δ/Δ mutant. In fact, the three Adr1-dependent genes <i>HGT17, MDH1,</i> and <i>PCK1</i> are required for growth on citrate, as indicated by deletion mutant phenotypes. The hyphal regulator <i>EED1</i> has a negative role in citrate utilization, and an <i>adr1</i>Δ/Δ <i>eed1</i>Δ/Δ double mutant is defective for growth on citrate. This result argues that Adr1 acts downstream or independently of Eed1 to govern citrate utilization. <i>C. albicans</i> Adr1 is rewired compared to its <i>S. cerevisiae</i> ortholog to govern the ability to use citrate, which <i>S. cerevisiae</i> lacks, and potentially to respond to Eed1, for which <i>S. cerevisiae</i> lacks an ortholog.IMPORTANCE<i>Candida albicans</i> is a major fungal pathogen of humans, and its ability to grow on a range of carbon sources is critical for pathogenicity. Here, we find that a known regulator of ergosterol synthesis, Adr1, is also required to use citrate as a carbon source. Adr1 acts downstream or independently of Eed1, a well-known regulator of hypha formation and citrate utilization.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0031125"},"PeriodicalIF":3.7,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266808","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":"Dynamics of amylopectin granule accumulation during the course of chronic <i>Toxoplasma</i> infection is linked to intra-cyst bradyzoite replication.","authors":"Aashutosh Tripathi, Ryan W Donkin, Joy S Miracle, Robert D Murphy, Matthew S Gentry, Abhijit Patwardhan, Anthony P Sinai","doi":"10.1128/msphere.00205-25","DOIUrl":"10.1128/msphere.00205-25","url":null,"abstract":"<p><p>The contribution of amylopectin granules (AG), a branched chain storage homopolymer of glucose, to the maintenance and progression of the chronic <i>Toxoplasma gondii</i> infection has remained undefined. Here, we describe the role of AG in the physiology of encysted bradyzoites using a purpose-developed imaging-based application, AmyloQuant, which permitted the quantification of relative levels of AG within <i>in vivo</i>-derived tissue cysts during the initiation and maturation of chronic infection. Our findings establish that AG are dynamic, exhibiting considerable heterogeneity among tissue cysts at all post-infection time points examined. Quantification of relative steady-state AG levels within tissue cysts reveals a previously unrecognized temporal cycle involving both phases of AG accumulation and utilization over the first 6 weeks of the chronic infection. This AG cycle is temporally coordinated with overall bradyzoite mitochondrial activity. In addition, the staging of AG levels is defined by a period of low accumulation, leading into a phase of high accumulation, followed by apparent rapid utilization associated with a coordinated burst of intra-cyst bradyzoite replication. These findings suggest that AG may represent a key component in the licensing of bradyzoite replication, intimately linking stored metabolic potential to the course of the chronic infection, thereby extending the impact of AG beyond the previously assigned role in transmission. These findings force a fundamental reassessment of the chronic <i>Toxoplasma</i> infection, highlighting the critical need to address the temporal progression of this crucial stage in the parasite life cycle.IMPORTANCEAmylopectin granules (AG) represent a storage polymer of glucose within <i>Toxoplasma gondii</i> bradyzoites, the life cycle stage associated with the chronic infection. In this study, we report on the development of AmyloQuant, an image-based application, to investigate the levels and distribution of AG within encysted bradyzoites in the murine brain with the progression of the chronic infection. Quantification reveals that AG, although heterogeneous both within and across tissue cysts, exhibit a previously unrecognized temporal cycle that is linked to the overall mitochondrial activity and the capacity to replicate <i>in vivo</i>. This confirms that encysted bradyzoites, long considered dormant, retain considerable metabolic activity, with AG playing a potentially critical role in defining and perhaps licensing the progression of this life-long persistent infection.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0020525"},"PeriodicalIF":3.7,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258521","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":"<i>Streptococcus pneumoniae</i> carriage in adults during the COVID-19 pandemic in Portugal: dominance of serotypes included in broader PCVs and of serotype 3.","authors":"Sónia T Almeida, A Cristina Paulo, Alexandra S Simões, Bárbara Ferreira, Raquel Sá-Leão","doi":"10.1128/msphere.00082-25","DOIUrl":"https://doi.org/10.1128/msphere.00082-25","url":null,"abstract":"<p><p><i>Streptococcus pneumoniae</i> (pneumococcus) is a leading cause of infections, particularly in infants and the elderly. Recent advances in molecular methods suggest higher pneumococcal carriage rates among adults than previously estimated, raising questions about their role in transmission. This study aimed to estimate pneumococcal carriage prevalence, identify circulating serotypes, and assess risk factors for colonization among adults during the COVID-19 pandemic in Portugal. We conducted a prospective observational study among civil servants aged ≥18 years in Oeiras Municipality from February 2021 to February 2022. Paired nasopharyngeal and oropharyngeal samples were analyzed using qPCR to detect pneumococcal carriage and 66 serotypes/serogroups. This included novel primers and probes for serotypes 4 and 24B/F, overcoming previous concerns associated with false positivity. Risk factors were identified using Bayesian adaptive sampling for variable selection in generalized linear model. Among 3,574 participants, 6.9% were pneumococcal carriers through qPCR without prior culture enrichment. Carriage rates were higher in oropharyngeal than nasopharyngeal samples (5.3% vs 3.7%, <i>P</i> < 0.001). Twenty-six serotypes/serogroups were identified, with the most common being non-encapsulated (NT), 10A, 23B, 3, 11A/D, 33A/F/37, 16F, and 31. Excluding NT, the most frequent serotypes collectively accounted for 45.3% of all carriers. Vaccine coverage estimates were 13.5% for PCV13, 20.4% for PCV15, 40.0% for PCV20, and 64.1% for PCV21. Contact with children < 18 years increased the odds of colonization by 2.73-fold (95% confidence interval [CI], 2.01-3.75), while being male reduced the odds by 54% (odds ratio = 0.46; 95% CI, 0.30-0.69). These findings emphasize the need for ongoing surveillance to clarify adults' role in pneumococcal transmission and support prevention strategies, including adult vaccination and community-level interventions, to mitigate pneumococcal disease.IMPORTANCE<i>Streptococcus pneumoniae</i> is a major pathogen causing significant disease worldwide, yet adult carriage remains underexplored. By evaluating pneumococcal carriage among adults in Portugal during the COVID-19 pandemic, this study provides critical insights into circulating serotypes, including those not targeted by 13-valent pneumococcal conjugate vaccine (PCV13), and highlights key risk factors such as contact with children and sex differences. The findings reveal substantial potential coverage for newer PCVs. This work underscores the importance of adult-focused prevention strategies, including vaccination and ongoing surveillance, to reduce pneumococcal transmission and disease burden in the community.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0008225"},"PeriodicalIF":3.7,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258520","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}