mSphere最新文献

{"title":"<i>Chlamydia trachomatis</i> TmeA promotes pedestal-like structure formation through N-WASP and TOCA-1 interactions.","authors":"Alix McCullough, C A Jabeena, Steve Huang, Brianna Steiert, Robert Faris, Mary M Weber","doi":"10.1128/msphere.00101-25","DOIUrl":"10.1128/msphere.00101-25","url":null,"abstract":"<p><p><i>Chlamydia trachomatis</i> (<i>C.t</i>.) is the causative agent of several human diseases, including the sexually transmitted infection chlamydia and the eye infection trachoma. As an obligate intracellular bacterial pathogen, invasion is critical for establishing infection and subsequent pathogenesis. During invasion, <i>C.t</i>. secretes effector proteins via its type III secretion system (T3SS), which manipulate host actin cytoskeletal regulation to promote bacterial entry. Previous studies identified the T3SS effector protein TmeA as a key factor in <i>C.t</i>. invasion, as it recruits and activates N-WASP. This interaction, in turn, activates the Arp2/3 complex, driving cytoskeletal rearrangements at the invasion site to drive <i>C.t</i>. uptake. In this study, we define the role of the N-WASP CRIB domain in mediating this interaction and demonstrate that TmeA functions as a mimic of Cdc42 as part of its established role in activating N-WASP. Additionally, we identified TOCA-1 as another host protein that directly interacts with TmeA. In other bacterial pathogens, notably an enterohemorrhagic <i>E. coli</i>, N-WASP and TOCA-1 are hijacked to mediate pedestal formation. Using siRNA-mediated knockdown of N-WASP and TOCA-1, followed by transmission electron microscopy, we found that both proteins are important for <i>C.t</i>.-mediated pedestal-like structure formation. Collectively, these findings expand our understanding of the intricacies of <i>C.t</i>. invasion, highlighting how TmeA-mediated interactions with N-WASP and TOCA-1 contribute to pedestal-like structure formation, which may represent an early step in <i>C.t</i>. infection.</p><p><strong>Importance: </strong><i>Chlamydia trachomatis</i> (<i>C.t.</i>) is an obligate intracellular bacterial pathogen that poses a significant threat to human health, being associated with various diseases, including chlamydia-the most prevalent bacterial sexually transmitted infection-and trachoma. Although often asymptomatic, chlamydia infections can lead to severe complications, such as infertility, ectopic pregnancy, and an increased risk of cervical and ovarian cancers. As an intracellular pathogen, host cell invasion is critical for <i>C.t.</i> survival and pathogenesis. In this study, we provide new insights into the interactions between the <i>C.t.</i> invasion effector protein TmeA and the host proteins N-WASP and TOCA-1, revealing that both host proteins are involved in pedestal-like structure formation during early stages of <i>C.t.</i> infection. These findings deepen our understanding of the mechanisms underlying TmeA-mediated host cell invasion and highlight a key pathway contributing to <i>C.t.</i>-mediated pathogenesis.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0010125"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108077/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144032126","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":"Characterizing antimicrobial activity of environmental <i>Streptomyces</i> spp. and oral bacterial and fungal isolates from <i>Canis familiaris</i> and <i>Felis catus</i>.","authors":"Audrey Cowen, Bonnie Yiu, Sara Fallah, Kirsten J Meyer, Emily Puumala, Yunjin Lee, Haley L Zubyk, Nicole Robbins, Justin R Nodwell, Jessie MacAlpine, Leah E Cowen","doi":"10.1128/msphere.00098-25","DOIUrl":"10.1128/msphere.00098-25","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Antimicrobials are a pillar of modern medicine, yet our limited arsenal of antibiotics and antifungals is currently threatened by widespread drug resistance. Ongoing efforts are focused on developing strategies to identify compounds that enhance the efficacy of current antimicrobials and develop novel, resistance-evasive therapeutic strategies. In this study, we characterized microbial isolates from two distinct environments to identify those that exhibit antimicrobial activity alone and in combination with current antimicrobials: (i) oral isolates from domesticated animals and (ii) environmental &lt;i&gt;Streptomyces&lt;/i&gt; spp. First, conditioned media prepared from bacterial and fungal oral isolates that were collected from &lt;i&gt;Canis familiaris&lt;/i&gt; and &lt;i&gt;Felis catus&lt;/i&gt; were screened for antibacterial and antifungal activity. Three supernatants from bacterial isolates exhibited antifungal activity against the human fungal pathogen &lt;i&gt;Candida albicans&lt;/i&gt; in the presence of subinhibitory concentrations of fluconazole, the most widely deployed antifungal. Additionally, two bacterial isolates displayed antibacterial activity against &lt;i&gt;Escherichia coli&lt;/i&gt; alone and in combination with the antibacterial ampicillin. Furthermore, 32 environmental isolates of confirmed and predicted &lt;i&gt;Streptomyces&lt;/i&gt; spp. were screened for activity against &lt;i&gt;C. albicans&lt;/i&gt; and &lt;i&gt;E. coli&lt;/i&gt;. Cell-free media harvested from isolates WAC5038 and WAC5287 exhibited antifungal activity against &lt;i&gt;Candida&lt;/i&gt; spp., while only the WAC5038-conditioned medium displayed antibacterial activity. Bioactivity-guided fractionation, coupled with UV/Vis absorbance spectra, suggested that the bioactive compound in WAC5287 has a similar absorbance spectrum to the antifungal class of polyenes, while the bioactive component of WAC5038 remains unknown. Overall, this work highlights a strategy to collect and screen environmental isolates for the identification of novel antimicrobials.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Importance: &lt;/strong&gt;The emergence and spread of antimicrobial resistance presents a global health challenge. As such, researchers are focused on developing pipelines to discover novel antimicrobials. In this study, we screened two distinct collections of microbes for antimicrobial activity. First, we collected bacterial and fungal isolates from the oral cavities of domesticated dogs and cats and identified these isolates using 16S (bacteria) and ITS (fungi) sequencing. Follow-up analyses confirmed that some conditioned media from bacterial isolates had antibacterial activity against &lt;i&gt;Escherichia coli&lt;/i&gt; and antifungal activity against &lt;i&gt;Candida albicans&lt;/i&gt; both alone and in combination with the current antimicrobial drugs. Additionally, screening 32 predicted or confirmed Streptomyces environmental isolates for antifungal and antibacterial activity identified two isolates with antifungal activity (WAC5038 and WAC5287), with only one isolate demonstrating antibacterial activity (WAC5038).","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0009825"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108073/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143983285","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":"Role of the multiple telomeric repeat arrays in integration, persistence, and efficacy of the commercial CVI988 vaccine.","authors":"Luca D Bertzbach, Yu You, Tereza Vychodil, Ahmed Kheimar, Lisa Kossak, Mohammad A Sabsabi, Andelé M Conradie, Benedikt B Kaufer","doi":"10.1128/msphere.00142-25","DOIUrl":"10.1128/msphere.00142-25","url":null,"abstract":"<p><p>Marek's disease virus (MDV) is a highly oncogenic alphaherpesvirus that causes fatal T cell lymphomas in chickens. Oncogenic MDV strains can integrate their genome into the host telomeres of latently infected and tumor cells. This integration process is facilitated by telomeric repeat arrays (TMR) present at the ends of the MDV genome, which consist of the hexanucleotide (TTAGGG)_<i>n</i> that is identical to host telomere sequences. In addition, integration of the virus genome is crucial for the development of lymphomas. Live-attenuated vaccines play a vital role in protecting chickens against this deadly disease, yet our understanding of their biology remains limited. Intriguingly, the commercial gold standard MDV vaccine, the live-attenuated MDV strain CVI988, also possesses TMR at the ends of its genome. In this study, we investigated the role of the multiple TMR arrays (mTMR) in vaccine virus integration, latency, reactivation, and protection against very virulent MDV. Our data revealed that the mTMR present in CVI988 are important for virus genome integration and maintenance in latently infected cells <i>in vitro</i>. In addition, virus latency, reactivation, and vaccine efficacy were reduced in an mTMR deleted mutant compared to the wild-type vaccine. These results provide valuable insights into the biology of this important vaccine virus and shed light on the roles of the mTMR in vaccine integration, latency, and protection against very virulent MDV.IMPORTANCEMarek's disease virus (MDV) is an oncogenic herpesvirus and causes lethal lymphomas in chickens. The gold standard vaccine is the live-attenuated MDV strain CVI988 (a.k.a. Rispens). CVI988 is extensively used in chickens worldwide due to its high efficacy in preventing disease and lymphomas. The CVI988 vaccine harbors telomere arrays (TMR) at the ends of its genome. TMR facilitate genome integration of oncogenic MDV strains into the host telomeres. This study provides critical insights into the biology of the widely used MDV vaccine strain CVI988, demonstrating the crucial role of mTMR in viral genome integration, latency, and protection against very virulent MDV. Furthermore, our findings enhance the understanding of MDV vaccine biology and may guide future strategies to improve Marek's disease control.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0014225"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108085/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144030085","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":"TEAL-Seq: targeted expression analysis sequencing.","authors":"Georgia Doing, Priya Shanbhag, Isaac Bell, Sara Cassidy, Efthymios Motakis, Elizabeth Aiken, Julia Oh, Mark D Adams","doi":"10.1128/msphere.00984-24","DOIUrl":"10.1128/msphere.00984-24","url":null,"abstract":"<p><p>Metagenome sequencing enables the genetic characterization of complex microbial communities. However, determining the activity of isolates within a community presents several challenges, including the wide range of organismal and gene expression abundances, the presence of host RNA, and low microbial biomass at many sites. To address these limitations, we developed \"targeted expression analysis sequencing\" or TEAL-seq, enabling sensitive species-specific analyses of gene expression using highly multiplexed custom probe pools. For proof of concept, we targeted about 1,700 core and accessory genes of <i>Staphylococcus aureus</i> and <i>S. epidermidis</i>, two key species of the skin microbiome. Two targeting methods were applied to laboratory cultures and human nasal swab specimens. Both methods showed a high degree of specificity, with >90% reads on target, even in the presence of complex microbial or human background DNA/RNA. Targeting using molecular inversion probes demonstrated excellent correlation in inferred expression levels with bulk RNA-seq. Furthermore, we show that a linear pre-amplification step to increase the number of nucleic acids for analysis yielded consistent and predictable results when applied to complex samples and enabled profiling of expression from as little as 1 ng of total RNA. TEAL-seq is much less expensive than bulk metatranscriptomic profiling, enables detection across a greater dynamic range, and uses a strategy that is readily configurable for determining the transcriptional status of organisms in any microbial community.IMPORTANCEThe gene expression patterns of bacteria in microbial communities reflect their activity and interactions with other community members. Measuring gene expression in complex microbiome contexts is challenging, however, due to the large dynamic range of microbial abundances and transcript levels. Here we describe an approach to assessing gene expression for specific species of interest using highly multiplexed pools of targeting probes. We show that an isothermal amplification step enables the profiling of low biomass samples. TEAL-seq should be widely adaptable to the study of microbial activity in natural environments.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0098424"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108068/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144021195","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":"Meningococcal vaccine 4CMenB elicits a robust cellular immune response that targets but is not consistently protective against <i>Neisseria gonorrhoeae</i> during murine vaginal infection.","authors":"Joseph J Zeppa, Jamie E Fegan, Pauline Maiello, Epshita A Islam, Isaac S Lee, Christine Pham, Laura-Lee Caruso, Scott D Gray-Owen","doi":"10.1128/msphere.00940-24","DOIUrl":"10.1128/msphere.00940-24","url":null,"abstract":"<p><p>Retrospective epidemiological studies suggest that the licensed serogroup B meningococcal vaccine 4CMenB (Bexsero) provides some protection against the closely related pathogen <i>Neisseria gonorrhoeae</i> in humans. This result has been replicated in murine models of gonococcal colonization, with a gonococci-reactive humoral response and more rapid clearance of vaginal infection. However, immunization with 4CMenB consistently elicits a robust humoral response but does not protect all individuals; hence, the correlates of protection remain undefined. Herein, we exploit the fact that 4CMenB promotes gonococcal clearance in only a subset of immunized mice to perform a broad analysis of the adaptive response in animals that are or are not protected. We observe that 4CMenB vaccination induces high levels of anti-neisserial antibodies in both serum and the vaginal lumen, and a robust cellular response highlighted by an increase in both conventional naïve and memory populations as well as unconventional lymphocyte subsets. Multiplex and flow cytometry results show that 4CMenB vaccination generates a robust, multi-faceted cytokine response that spans numerous T cell subsets (T_H1, T_H2, T_reg, and T_H17) and that non-T non-B lymphocytes play an important role in this response, as indicated by an unbiased principal component analysis. Together, this work provides the first comprehensive analysis of the robust humoral and complex cellular response to 4CMenB so as to reveal the effector mechanisms that may contribute to immunity against vaginal gonococcal infection.IMPORTANCEGonorrhea, a sexually transmitted infection caused by the human-specific pathogen <i>Neisseria gonorrhoeae</i> (Ngo), is a growing public health concern due to its rise in prevalence and increasing antibiotic resistance against first-line agents. There is currently no vaccine available for this important bacterium due, in part, to our lack of understanding of immune correlates of protection. Interestingly, a human-approved vaccine (4CMenB; Bexsero) against a related pathogen (<i>N. meningitidis</i>; a cause of meningitis) has demonstrated some protection against gonorrhea in epidemiologic studies. Herein, we provide the first detailed analysis of cellular and antibody-mediated immune responses to this vaccine in animals protected against gonococcal colonization. These findings provide new understanding regarding immune correlates of protection against <i>N. gonorrhoeae</i>, providing new insight into immune protection and helping guide the development of a much-needed vaccine.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0094024"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108064/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144019829","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":"Signal sequences target enzymes and structural proteins to bacterial microcompartments and are critical for microcompartment formation.","authors":"Elizabeth R Johnson, Nolan W Kennedy, Carolyn E Mills, Shiqi Liang, Swetha Chandrasekar, Taylor M Nichols, Grant A Rybnicky, Danielle Tullman-Ercek","doi":"10.1128/msphere.00962-24","DOIUrl":"10.1128/msphere.00962-24","url":null,"abstract":"<p><p>Spatial organization of pathway enzymes has emerged as a promising tool to address several challenges in metabolic engineering, such as flux imbalances and off-target product formation. Bacterial microcompartments (MCPs) are a spatial organization strategy used natively by many bacteria to encapsulate metabolic pathways that produce toxic, volatile intermediates. Several recent studies have focused on engineering MCPs to encapsulate heterologous pathways of interest, but how this engineering affects MCP assembly and function is poorly understood. In this study, we investigated the role of signal sequences, short domains that target proteins to the MCP core, in the assembly of 1,2-propanediol utilization (Pdu) MCPs. We characterized two novel Pdu signal sequences on the structural proteins PduM and PduB, which constitute the first report of metabolosome signal sequences on structural proteins rather than enzymes. We then explored the role of enzymatic and structural Pdu signal sequences on MCP assembly by deleting their encoding sequences from the genome alone and in combination. Deleting enzymatic signal sequences decreased the MCP formation, but this defect could be recovered in some cases by overexpressing genes encoding the knocked-out signal sequence fused to a heterologous protein. By contrast, deleting structural signal sequences caused similar defects to knocking out the genes encoding the full-length PduM and PduB proteins. Our results contribute to a growing understanding of how MCPs form and function in bacteria and provide strategies to mitigate assembly disruption when encapsulating heterologous pathways in MCPs.IMPORTANCESpatially organizing biosynthetic pathway enzymes is a promising strategy to increase pathway throughput and yield. Bacterial microcompartments (MCPs) are proteinaceous organelles that many bacteria natively use as a spatial organization strategy to encapsulate niche metabolic pathways, providing significant metabolic benefits. Encapsulating heterologous pathways of interest in MCPs could confer these benefits to industrially relevant pathways. Here, we investigate the role of signal sequences, short domains that target proteins for encapsulation in MCPs, in the assembly of 1,2-propanediol utilization (Pdu) MCPs. We characterize two novel signal sequences on structural proteins, constituting the first Pdu signal sequences found on structural proteins rather than enzymes, and perform knockout studies to compare the impacts of enzymatic and structural signal sequences on MCP assembly. Our results demonstrate that enzymatic and structural signal sequences play critical but distinct roles in Pdu MCP assembly and provide design rules for engineering MCPs while minimizing disruption to MCP assembly.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0096224"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108088/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144030088","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":"Rhizosphere-colonizing bacteria persist in the protist microbiome.","authors":"Stephen J Taerum, Ravikumar R Patel, Justin E Alamo, Daniel Gage, Blaire Steven, Lindsay R Triplett","doi":"10.1128/msphere.00037-25","DOIUrl":"10.1128/msphere.00037-25","url":null,"abstract":"<p><p>Soils contain diverse predatory protists that affect the abundance and behavior of rhizosphere bacteria, including bacteria that may benefit plant health. Protists harbor their own bacterial microbiomes, and we previously observed that plants inoculated with protists harbored rhizosphere bacteria similar to those in the protist inoculum. To determine how protist microbiomes affect the rhizosphere, we profiled the bacteria of eight diverse rhizosphere protist isolates after 2 years of laboratory culture. We then compared the protist culture microbiomes to maize rhizosphere communities 6 weeks after protist inoculation. Introduction of protists enriched 13 protist-associated bacterial amplicon sequence variants (ASVs) in the rhizosphere, which comprised ~10% of the rhizosphere bacterial community. Additional bacterial ASVs ranked highly in abundance in both rhizosphere (top 100) and protist (top 20) microbiomes; together, a median 47% of the protist microbiome was enriched or in high rank abundance in the rhizosphere. Inoculation with three out of eight protist cultures positively affected root biomass traits, but a protist mixture had no effect, indicating that the impact of protist-associated bacteria on plant growth is context dependent. Isolates of protist-associated bacteria had both positive and negative effects on protist growth in culture, suggesting that the bacteria use multiple strategies to survive in proximity to predators. This study demonstrates that even after long-term laboratory culture, rhizosphere protist cultures host bacteria that can colonize the rhizosphere of maize. The findings also identify diverse groups of rhizosphere-colonizing bacteria that persist among protist predators, which suggests that these bacteria could associate with or benefit from protists in the soil.</p><p><strong>Importance: </strong>Understanding the impact of predatory protists on the plant microbiome will be essential to deploy protists in sustainable agriculture. This study shows that eight rhizosphere protist isolates hosted diverse and distinct bacterial communities and that a large proportion of these bacteria could be found colonizing the maize root environment 6 weeks after protists were inoculated onto seedlings. This study demonstrates that certain bacteria from the maize rhizosphere can persist for years in protist cultures and retain the ability to colonize rhizosphere soil, suggesting that protists might support the survival of these rhizosphere bacteria in the absence of the plant.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0003725"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108058/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144037475","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":"Antibiofilm properties of 4-hydroxy-3-methyl-2-alkenylquinoline, a novel <i>Burkholderia</i>-derived alkaloid.","authors":"McKinley D Williams, Taylor R Sweeney, Sabrina Trieu, Ravi Orugunty, Abdelahhad Barbour, Fereshteh Younesi, Michael Glogauer, Nopakorn Hansanant, Ronald Shin, Shi-En Lu, Kevin Cao, Abraham Tenorio, Sigmund J Haidacher, Anthony M Haag, Thomas D Horvath, Leif Smith","doi":"10.1128/msphere.01081-24","DOIUrl":"10.1128/msphere.01081-24","url":null,"abstract":"<p><p>Biofilms are an important colonization mechanism employed by several microbial species to better establish themselves and monopolize the acquisition of resources across different environs. Some bacteria have evolved specialized metabolites that, when secreted, disrupt the formation and stability of biofilms generated by competing heterospecies, providing the producing organism with an ecological advantage. Soil-derived species are probable candidates for the identification of such compounds, given the intense level of competition that occurs within the terrestrial ecosystem. The MS14 strain of <i>Burkholderia contaminans</i> isolated from soil in Mississippi has previously been shown to produce antimicrobial compounds like occidiofungin and ornibactin. In this report, we demonstrate that this strain also produces 4-hydroxy-3-methyl-2-alkenylquinoline (HMAQ-7), an alkaloid-based metabolite structurally similar to others produced by <i>Burkholderia</i>. HMAQ-7 was isolated and purified in sufficient quantities to enable the elucidation of its covalent structure and the evaluation of its biological effects. The compound was found to possess a unique ability to inhibit biofilm biosynthesis in several species, including opportunistic pathogens like <i>Staphylococcus haemolyticus</i> and within saliva-derived multispecies biofilms. HMAQ-7 also demonstrated an ability to modulate additional cellular behaviors in <i>Bacillus subtilis,</i> including motility and sporulation, suggesting that this molecule is important to the interspecies dynamics present across many diverse microenvironments.IMPORTANCEThe present study furthers our understanding of the structural complexity and the biological functions of the 2-alkyl-4(1H)-quinolone metabolites produced by <i>Burkholderia</i> spp. Low micromolar concentrations of HMAQ-7' induced observable bacterial growth morphology differences. The antibiofilm properties of the HMAQ-7' characterized in this study will promote future investigations into possible biological and applied roles. The ability to alter biofilm formation using HMAQ-7' may facilitate <i>Burkholderia</i> spp. colonization in a multitude of environments, that is, aquatic, soil, and possibly during infection. HMAQ may subvert competition by potential competitor species in natural environments of <i>Burkholderia</i> spp. and possibly lung infections of cystic fibrosis patients.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0108124"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108052/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144009033","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 host and bacterial genetic approaches to define virulence strategies and protective immunity during <i>Mycobacterium tuberculosis</i> infection.","authors":"Andrew J Olive","doi":"10.1128/msphere.00517-24","DOIUrl":"10.1128/msphere.00517-24","url":null,"abstract":"<p><p>Infections with <i>Mycobacterium tuberculosis</i> (Mtb) resulted in over one million deaths in 2024, the highest number for any infectious disease. With no vaccines that protect against pulmonary tuberculosis (TB) and the challenges associated with antibiotic therapy, there is a critical need to better understand host-Mtb interactions to help curb this major public health problem. Mtb is arguably the most successful human pathogen, and it survives in diverse environments, resulting in heterogeneous disease outcomes in patients. Five years ago, in my commentary in mSphere, I discussed how Mtb virulence strategies that sense, adapt, and evade killing in the host can be uncovered using genetic approaches. Here, I will come full circle to highlight genetic approaches that recently uncovered new mechanisms regulating protective host responses and Mtb survival tactics. The goal is to highlight a genetic framework to probe a range of unexplored Mtb phenotypes, increase our understanding of host-Mtb interactions, and identify new therapeutic targets that may help prevent TB.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0051724"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108062/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144028822","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":"Toward a deeper understanding of dengue: novel method for quantification and isolation of envelope protein epitope-specific antibodies.","authors":"Sokchea Lay, Candice Bohaud, Sopheak Sorn, Sreymom Ken, Felix A Rey, Kevin K Ariën, Sowath Ly, Veasna Duong, Giovanna Barba-Spaeth, Heidi Auerswald, Tineke Cantaert","doi":"10.1128/msphere.00961-24","DOIUrl":"10.1128/msphere.00961-24","url":null,"abstract":"<p><p>The dengue viruses (DENV) envelope (E) protein is the main target of the antibody (Ab) response. Abs target different epitopes on the E-protein, including sE-dimer, E domain III (EDIII), and fusion loop (FL). Anti-EDIII Abs are mainly serotype-specific, whereas anti-FL Abs can induce antibody-dependent enhancement (ADE) <i>in vitro</i>. Abs targeting sE-dimer epitopes can cross-neutralize different DENV serotypes. However, the involvement of each Ab subset in disease pathogenicity and/or protection remains unclear. We aimed to optimize the quantification and purification of DENV E-protein epitope-specific Abs from human samples. C-terminal biotinylated DENV2 E recombinant proteins (EDIII, soluble E [sE], and sE-dimer) were coupled to color-coded magnetic microspheres for a multiplex immunoassay (MIA), testing different antigen concentrations. Assay performance was evaluated using well-characterized anti-DENV monoclonal antibodies (mAbs) and total IgG from DENV seronegative and seropositive human plasma. Specific FL epitopes were blocked with mouse mAb clone 4G2 to quantify anti-FL- and sE-dimer-specific Abs, measuring antigen-antibody reactions as median fluorescence intensity (MFI). For isolation of E-protein epitope-specific antibodies, sE-proteins were conjugated to streptavidin resin beads. Total IgG from human plasma was incubated with immobilized EDIII to elute anti-EDIII Abs. The flow-through was incubated with sE-dimer resin beads to elute sE-dimer specific Ab enriched fraction, and the flow-through was applied to immobilized sE to elute anti-FL Abs. In conclusion, we have developed a serological assay to detect E-protein epitope-specific Abs in DENV-infected humans. Additionally, we successfully isolated anti-EDIII, anti-FL, and an enriched fraction of sE-dimer specific Abs from human samples.IMPORTANCEThe development of effective dengue virus (DENV) vaccines has been hampered by limited insights into the immunological mechanisms of protection. Our study addresses this gap by introducing a refined multiplex microsphere-based immunoassay (MIA) to quantify and isolate antibodies (Abs) targeting specific E-protein epitopes, such as E domain III (EDIII), the fusion loop (FL), and the sE-dimer specific Abs. This method provides detailed epitope-specific Ab profiling with high sensitivity and requires minimal sample volumes. The ability to isolate specific Ab subsets from human plasma also enables detailed investigations into their roles in protection or pathogenesis, paving the way for more effective dengue interventions.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0096124"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108060/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143991362","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}