mSphere最新文献

{"title":"Characterization of a novel <i>Leishmania</i> antigen containing a repetitive domain and its potential use as a prophylactic and therapeutic vaccine.","authors":"Bianca de Oliveira, Wanessa M Goes, Frederico C Nascimento, Juliana B T Carnielli, Eden R Ferreira, Alex Fiorini de Carvalho, Pablo Victor Mendes Dos Reis, Milton Pereira, Tiago Queiroga Nery Ricotta, Liliane Martins Dos Santos, Renan Pedra de Souza, Diego Esteban Cargnelutti, Jeremy C Mottram, Santuza R Teixeira, Ana Paula Fernandes, Ricardo T Gazzinelli","doi":"10.1128/msphere.00097-25","DOIUrl":"10.1128/msphere.00097-25","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Human visceral leishmaniasis (HVL) is the second most lethal tropical parasitic disease. Currently, no prophylactic or therapeutic vaccines exist for HVL. Thus, the development of an efficacious vaccine is still needed. We previously performed an immunoproteomics analysis on &lt;i&gt;Leishmania amazonensis&lt;/i&gt; parasite extracts to identify immunodominant antigens recognized by the sera of vaccinated and protected mice. Among the identified antigens, we discovered a novel, previously unstudied repetitive protein, initially annotated in &lt;i&gt;Leishmania&lt;/i&gt; genomes as a kinetoplast-associated protein-like protein from &lt;i&gt;Leishmania infantum&lt;/i&gt; (LinKAP), containing conserved domains (trichohyalin-plectin-homology [TPH] and TolA) that are associated with other mitochondrial proteins. LinKAP sequences are conserved across trypanosomatids, including &lt;i&gt;Endotrypanum, Leishmania,&lt;/i&gt; and &lt;i&gt;Trypanosoma&lt;/i&gt; species. Using differential centrifugation of &lt;i&gt;Leishmania&lt;/i&gt; subcellular structures, we showed that LinKAP was enriched in fractions colocalizing with other mitochondrial proteins. mNeonGreen labeling at the endogenous locus using CRISPR-Cas9 and confocal microscopy confirmed that LinKAP is a mitochondrial-associated protein in &lt;i&gt;Leishmania&lt;/i&gt; but not specifically colocalized with kDNA. We cloned and expressed a truncated version of LinKAP (rLinKAP), containing part (15) of the several LinKAP amino acid repeats, demonstrating over 85% homology across &lt;i&gt;L. infantum, L. amazonensis, L. braziliensis,&lt;/i&gt; and &lt;i&gt;L. mexicana&lt;/i&gt; species. An adjuvanted formulation of LinKAP with Poly ICLC, a polyinosinic-polycytidylic acid (Poly I:C) stabilized with carboxymethylcellulose and polylysine, was used to vaccinate mice and hamsters as a prophylactic vaccine for visceral leishmaniasis. Animals immunized with rLinKAP showed a potent cellular and humoral response and a significant decrease in tissue parasitism when challenged with &lt;i&gt;L. infantum&lt;/i&gt;. We also tested rLinKAP as a therapeutic vaccine in mice. Following therapeutic vaccination, antibody responses were enhanced, and cellular responses became apparent. Our treatment protocol inhibited splenic parasite burden by 75% in treated mice. In conclusion, our antigen discovery strategy and the observed protective effect highlight rLinKAP as a promising vaccine candidate for leishmaniasis.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Importance: &lt;/strong&gt;A previous reverse vaccinology study identified kinetoplast-associated protein-like protein from &lt;i&gt;Leishmania infantum&lt;/i&gt; (LinKAP) as a potential new vaccine target, as this protein was recognized by the sera of protected mice in extracts of &lt;i&gt;Leishmania&lt;/i&gt; promastigotes. Interestingly, LinKAP is a repetitive protein containing trichohyalin-plectin-homology (TPH) and TolA domains and was initially annotated as a kinetoplast-associated protein. We further characterized LinKAP as a mitochondrial-associated protein highly conserved among trypanosomatids. We also validated LinKAP as a promis","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0009725"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108087/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144064161","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":"Pear flower and leaf microbiome dynamics during the naturally occurring spread of <i>Erwinia amylovora</i>.","authors":"Aia Oz, Orly Mairesse, Shira Raikin, Hila Hanani, Hadar Mor, Mery Dafny Yelin, Itai Sharon","doi":"10.1128/msphere.00011-25","DOIUrl":"10.1128/msphere.00011-25","url":null,"abstract":"<p><p><i>Erwinia amylovora</i> is the causal pathogen of fire blight, a contagious disease that affects apple and pear trees and other members of the family Rosaceae. In this study, we investigated the community dynamics of the pear flower microbiome in an agricultural setting during the naturally occurring infection of <i>E. amylovora</i>. Five potential factors were considered: collection date, the flower's phenological stage, location on the tree, location within the orchard, and pear cultivar. The phenological stage and the collection date were identified as the most important factors associated with pear flower microbiome composition, while the location of the tree in the orchard and the flower's location on the tree had a marginal effect. The leaf microbiome reflected that of the abundant phenological stage on each date. The flower microbiome shifted toward <i>E. amylovora</i> dominating the community as time and phenological stages progressed, leading to a decreased community diversity. The <i>E. amylovora</i> population was represented almost exclusively by six amplicon sequence variants (ASVs) with similar proportions throughout the entire collection period. Other taxa, including <i>Pseudomonas</i>, <i>Pantoea</i>, <i>Lactobacillus</i>, and <i>Sphingomonas</i>, were represented by dozens of ASVs, and different succession patterns in their populations were observed. Some of the taxa identified include known antagonists to <i>E. amylovora</i>. Overall, our results suggest that flower physiology and the interaction with the environment are strongly associated with the pear flower microbiome and should be considered separately. Taxon-specific succession patterns under <i>E. amylovora</i> spread should be considered when choosing candidates for antagonist-based treatments for fire blight.IMPORTANCEThe spread of pathogens in plants is an important ecological phenomenon and has a significant economic impact on agriculture. Flowers serve as the entry point for <i>E. amylovora,</i> but members of the flower microbiome can inhibit or slow down the proliferation and penetration of the pathogen. Knowledge about leaf and flower microbiome response to the naturally occurring spread of <i>E. amylovora</i> is still lacking. The current study is the first to describe the Rosaceae flower microbiome dynamics during the naturally occurring infection <i>of E. amylovora</i>. Unlike previous studies, the study design enabled us to evaluate the contribution of five important environmental parameters to community composition. We identified different ASV succession patterns across different taxa in the flower consortia throughout the season. These results contribute to our understanding of plant microbial ecology during pathogen spread and can help improve biological treatments for fire blight.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0001125"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108086/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144037472","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":"Adaptation of the tetracycline-repressible system for modulating the expression of essential genes in <i>Cryptococcus neoformans</i>.","authors":"Ci Fu, Nicole Robbins, Leah E Cowen","doi":"10.1128/msphere.01018-24","DOIUrl":"10.1128/msphere.01018-24","url":null,"abstract":"<p><p>The opportunistic human fungal pathogen <i>Cryptococcus neoformans</i> has an enormous impact on human health as the causative agent of cryptococcal meningitis, and there is a dire need to expand our current antifungal arsenal. Essential gene products often serve as ideal targets for antimicrobials, and identifying and characterizing essential genes in a pathogen of interest is critical for drug development. Unfortunately, characterization of essential genes in <i>C. neoformans</i> is limited due to its haploid nature and lack of genetic tools for generating effective conditional-expression mutants. To date, the copper-repressible promoter <i>pCTR4</i> is the most widely used system to regulate essential gene expression; however, its expression is leaky and copper has pleiotropic effects. In diverse fungal species, including <i>Saccharomyces cerevisiae</i>, <i>Candida albicans</i>, and <i>Candida auris</i>, the tetracycline-repressible promoter system is a powerful tool to regulate gene expression; however, it has yet to be adapted for <i>C. neoformans</i>. In this study, we successfully implemented the tetracycline-repressible system in <i>C. neoformans</i> to regulate the expression of the essential genes <i>HSP90</i> and <i>FKS1</i>. Supplementation of cultures with the tetracycline analog doxycycline efficiently depleted <i>HSP90</i> at both transcript and protein levels and inhibited <i>C. neoformans</i> growth and viability. Similarly, the depletion of <i>FKS1</i> with doxycycline enhanced sensitivity of the strain to the echinocandin caspofungin, an antifungal that targets the glucan synthase but is generally ineffective against <i>C. neoformans</i>. Thus, this work unveils a novel approach to generate conditional-expression mutants in <i>C. neoformans,</i> providing unprecedented potential to systematically study essential gene function in this important human fungal pathogen.IMPORTANCEInvasive fungal infections cause millions of deaths annually, while the number of antifungals available to combat these pathogens is limited to only three classes: polyenes, azoles, and echinocandins. The largest source of novel antifungal drug targets are essential gene products, which are required for cellular viability. However, tools to identify and characterize essential genes in <i>C. neoformans</i> are extremely limited. Here, we adapted the tetracycline-repressible promoter system, that has been widely used in other organisms, to study essential gene function in <i>C. neoformans</i>. By placing this regulatable promoter upstream of the essential genes <i>HSP90</i> and <i>FKS1</i>, we confirmed that the growth of the strains in the presence of the tetracycline analog doxycycline results in the depletion of essential gene expression. This approach provides a significant advance for the systematic study of essential genes in <i>C. neoformans</i>.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0101824"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108051/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143973522","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":"Risk of death during acute infection is accelerating across diverse host-pathogen systems and consistent with multiple models of host-pathogen interaction.","authors":"Tim O'Sullivan, Canan Karakoç, Kristofer Wollein Waldetoft, Sam P Brown","doi":"10.1128/msphere.00953-24","DOIUrl":"10.1128/msphere.00953-24","url":null,"abstract":"<p><p>Infectious diseases remain a major cause of global mortality, yet basic questions concerning the relationship between within-host processes governing pathogen burden (pathogen replication, immune responses) and population-scale (epidemiological) patterns of mortality remain obscure. We use a structured literature review to leverage the extensive biomedical data generated by controlled host infections to address the epidemiological question of whether infection-induced mortality is constant, accelerating, or follows some other pattern of change and to infer the within-host mechanistic basis of this pattern. We show that across diverse lethal infection models, the risk of death increases approximately exponentially in time since infection, in a manner phenomenologically similar to the dynamics of all-cause death. We further show that this pattern of accelerating risk is consistent with multiple alternate mechanisms of pathogen growth and host-pathogen interaction, underlining the limitations of current experimental approaches to connect within-host processes to epidemiological patterns. We review critical experimental questions that our work highlights, requiring additional non-invasive data on pathogen burden throughout the course of infection.IMPORTANCEHere, we ask a simple question: what are the dynamics of pathogen-induced death? Death is a central phenotype in both biomedical and epidemiological infectious disease biology, yet very little work has attempted to link the biomedical focus on pathogen dynamics within a host and the epidemiological focus on populations of infected hosts. To systematically characterize the dynamics of death in controlled animal infections, we analyzed 209 data sets spanning diverse lethal animal infection models. Across experimental models, we find robust support for an accelerating risk of death since the time of infection, contrasting with conventional epidemiological models that assume a constant elevated risk of death. Using math models, we show that multiple processes of growth and virulence are consistent with accelerating risk of death, and we end with a discussion of critical experiments to resolve how within-host biomedical processes map onto epidemiological patterns of disease.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0095324"},"PeriodicalIF":3.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12108055/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144036083","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":"Reply to Nachamkin, \"Diversity of <i>Campylobacter</i> species in a rhesus macaque breeding colony\".","authors":"Rebecca L Bacon, Carolyn L Hodo, Sara D Lawhon","doi":"10.1128/msphere.00041-25","DOIUrl":"10.1128/msphere.00041-25","url":null,"abstract":"","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0004125"},"PeriodicalIF":3.7,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12039219/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143701126","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":"A response to iron involving carbon metabolism in the opportunistic fungal pathogen <i>Candida albicans</i>.","authors":"Ritu Garg, Zhengkai Zhu, Francisco G Hernandez, Yiran Wang, Marika S David, Vincent M Bruno, Valeria C Culotta","doi":"10.1128/msphere.00040-25","DOIUrl":"10.1128/msphere.00040-25","url":null,"abstract":"<p><p>Iron (Fe) is an essential micronutrient, and during infection, the host attempts to starve pathogens of this vital element through a process known as nutritional immunity. Successful pathogens have evolved means to evade this attack, an example being <i>Candida albicans,</i> the most prevalent human fungal pathogen. When Fe-starved, <i>C. albicans</i> induces multiple pathways for Fe uptake using the SEF1 trans-regulator, and we now describe a previously unrecognized effect of Fe on <i>C. albicans</i> metabolism that occurs independent of SEF1. Specifically, Fe limitation leads to inhibition of pyruvate dehydrogenase (PDH) connecting glycolysis to mitochondrial respiration. PDH inactivation involves loss of the LAT1 catalytic subunit harboring a lipoic acid co-factor. Protein lipoylation is a Fe-S dependent process, and lipoylated alpha-ketoglutarate dehydrogenase is also inhibited in Fe-starved <i>C. albicans</i>. SEF1 does not protect against PDH inactivation, and despite SEF1 induction of Fe import genes, cellular Fe levels drop dramatically during chronic Fe starvation. Such loss of LAT1 and lipoylation is also seen in Fe-starved bakers' yeast <i>Saccharomyces cerevisiae</i>. In both yeast species, glucose is diverted toward the pentose phosphate pathway (PPP) and PPP production of NADPH is increased in response to low Fe and PDH loss. Additionally, glucose consumption is lowered in Fe-starved <i>C. albicans</i>, and non-PDH alternatives to producing Ac-CoA are induced, including pyruvate bypass and fatty acid oxidation pathways. <i>C. albicans</i> can adapt well to the effects of micronutrient loss on cell metabolism.</p><p><strong>Importance: </strong>We describe a new response to Fe-starvation in a fungal pathogen involving carbon metabolism. Pyruvate dehydrogenase (PDH) that is central to glucose metabolism is inactivated at the post-translational level in Fe-starved cells. Nevertheless, the fungal pathogen can thrive by activating backup systems for metabolizing glucose. Methods that inhibit these compensatory pathways for carbon metabolism may prove beneficial in future anti-fungal strategies.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0004025"},"PeriodicalIF":3.7,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12039268/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143780615","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":"Variable phylosymbiosis and cophylogeny patterns in wild fish gut microbiota of a large subtropical river.","authors":"Yaqiu Liu, Xinhui Li, Konstantinos Ar Kormas, Yuefei Li, Huifeng Li, Jie Li","doi":"10.1128/msphere.00982-24","DOIUrl":"10.1128/msphere.00982-24","url":null,"abstract":"<p><p>The persistence and specificity of fish host-microbial interaction during evolution is an important part of exploring the host-microbial symbiosis mechanism. However, it remains unclear how the environmental and host factors shape fish host-microbe symbiotic relationships in subtropical rivers with complex natural environments. Freshwater fish are important consumers in rivers and lakes and are considered keystone species in maintaining the stability of food webs there. In this study, patterns and mechanisms shaping gut microbiota community in 42 fish species from the Pearl River, in the subtropical zone of China, were investigated. The results showed that fish host specificity is a key driver of gut microbiota evolution and diversification. Different taxonomic levels of the host showed different degrees of contribution to gut microbiota variation. Geographical location and habitat type were the next most important factors in shaping gut microbiota across the 42 fishes, followed by diet and gut trait. Our results emphasized the contribution of stochastic processes (drift and homogenizing dispersal) in the gut microbial community assembly of freshwater fishes in the middle and lower reaches of the Pearl River. Phylosymbiosis is evident at both global and local levels, which are jointly shaped by complex factors including ecological or host physiological filtration and evolutionary processes. The core microbiota showed co-evolutionary relationships of varying degrees with different taxonomic groups. We speculate that host genetic isolation or habitat variation facilitates the heterogeneous selection (deterministic process), which occurs and results in different host-core bacterium specificity.</p><p><strong>Importance: </strong>Freshwater fish are regarded as the dominant consumers in rivers and lakes. Due to their diverse feeding modes, fish significantly enhance the trophic link and nutrient recycling/retention in aquatic habitats. For this, they are often considered keystone species in maintaining the stability of food webs in rivers and lakes. A significant part of fish nutrition is essentially mediated by their gut microbiota, which can enhance fish tolerance to fluctuations in external resources and improve the efficiency of nutrients extracted from various food sources. As gut bacterial symbionts have a profound impact on the nutrition and development of their hosts, as well as their overall fitness, it is critical to answer the question of how hosts maintain these benefits by procuring or inheriting these vital symbionts, which is still largely unanswered, especially for freshwater fish. Our study provides new insights into the co-evolutionary relationship between wild fish and their symbiotic microbiome, the hidden diversity of gut microbiome, and the ecological adaptation potential of wild freshwater fish.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0098224"},"PeriodicalIF":3.7,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12039269/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143731036","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":"Alarmone ppGpp modulates bacterial motility, zeamine production, and virulence of <i>Dickeya oryzae</i> through the regulation of and cooperation with the putrescine signaling mechanism.","authors":"Zurong Shi, Zhibin Liang, Qian Yang, Lian-Hui Zhang, Qingwei Wang","doi":"10.1128/msphere.00682-24","DOIUrl":"10.1128/msphere.00682-24","url":null,"abstract":"<p><p>Putrescine is an important interspecies and interkingdom communication signal, modulating the bacterial motility, biofilm formation, and virulence of <i>D. oryzae</i>. The understanding of the regulation of putrescine biosynthesis and transport in <i>D. oryzae</i> is limited. In this study, we report that alarmone ppGpp hierarchically modulates putrescine biosynthesis and transport and synergistically cooperates with putrescine to regulate virulence traits and the virulence of <i>D. oryzae</i>. We found that the alarmone ppGpp synthesized by RelA regulated putrescine biosynthesis through modulating <i>speA</i> expression, and the product putrescine would thus inhibit the expression of <i>potF</i> and <i>plaP</i>. Remarkably, we unveiled the synergistic effect of alarmone ppGpp and putrescine on the modulation of swimming motility and zeamine production. Compared with the single deletion of either <i>relA</i> or <i>speA</i>, the double deletion of <i>relA</i> and <i>speA</i> could decrease the expression of RNA chaperone encoded gene <i>hfq</i> and the production of phytotoxin zeamine, which further attenuated the capability of <i>D. oryzae</i> EC1 in inhibition of rice seed germination. Collectively, the findings from this study depict alarmone ppGpp regulation on putrescine biosynthesis and transport and present the cooperation of regulation of alarmone ppGpp and putrescine in the virulence of <i>D. oryzae</i>.IMPORTANCE<i>Dickeya oryzae</i> is the causal agent of rice root rot disease. Bacterial motility and phytotoxic zeamines are characterized as two major virulent factors during <i>D. oryzea</i> infecting rice seed. Putrescine, as an interspecies and interkingdom communication signal for the infections of <i>D. oryzae</i>, has been previously demonstrated to be involved in the modulation of bacterial motility. Here we report the novel synergistic effect of putrescine signal and alarmone ppGpp on the regulation of both zeamine production and bacterial motility via modulating the expression of RNA chaperone-encoded gene <i>hfq</i>. In addition, we also showed that alarmone ppGpp hierarchically modulates putrescine biosynthesis and transport. Therefore, the findings of this study unveil the previously undetermined contribution of putrescine in the modulation of virulence determinants, and the regulatory mechanism of putrescine biosynthesis and transport in <i>D. oryzae</i>.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0068224"},"PeriodicalIF":3.7,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12039241/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143664088","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":"Assessment of periodontitis vaccine using three different bacterial outer membrane vesicles in canine model.","authors":"Ryoma Nakao, Takehiro Yamaguchi, Haruka Shibasaki, Jun Saeki, Aoi Takahashi, Ryunosuke Tominaga, Kimihiro Abe, Yukihiro Akeda, Tomoyo Nakagawa-Nakamura, Tomohiko Nishino, Kazuyuki Ishihara, Atsushi Jinno-Oue, Satoshi Inoue","doi":"10.1128/msphere.01033-24","DOIUrl":"10.1128/msphere.01033-24","url":null,"abstract":"<p><p>Canines frequently develop periodontitis, which is similar and relevant to immunopathology and microbiology of human periodontitis. The aim of this study was to investigate whether bacterial outer membrane vesicle (OMV)-based periodontal vaccines induced humoral immune response in canines from a human vaccine development perspective. <i>Porphyromonas gingivalis</i> (Pg) and <i>Treponema denticola</i> (Td), two major periodontal pathobionts, were chosen as vaccine targets. Intranasal (IN) immunization with Pg OMVs and Td OMVs strongly elicited humoral immune responses against the two respective species in preparative mouse experiments, particularly when adjuvanted with a probiotic <i>Escherichia coli</i> derivative (EcNΔ<i>flhD</i>)-derived OMVs. However, in beagles, intranasal immunization with the same Pg/Td/EcNΔ<i>flhD</i> OMV vaccine insufficiently elicits humoral immune responses. Nevertheless, the subcutaneous booster with the same OMVs dramatically improved antibody responses in both systemic blood circulation and mucosal sites such as eyes, oral cavity, and upper and lower respiratory tracts. Metagenomic analysis of salivary microbiota revealed that the OMV vaccine might change the microbial composition, while not reducing the number of any periodontal pathobionts at least during the timeframe of the present beagle study. In <i>in vitro</i> Pg growth inhibition assay, serum samples from OMV-immunized beagles significantly inhibited growth of the gingipain-deficient strain but not the gingipain-expressing wild-type strain. Taken together, our data offer the trivalent OMV vaccine strategy by IN-prime/SC-boost regimen, which could elicit robust mucosal immune responses, while suggesting the requirement of revised periodontal vaccine regimen toward achievement of sterilizing immunity in the oral cavity.</p><p><strong>Importance: </strong>Bacterial outer-membrane vesicles (OMVs) are attractive for use as novel nanoparticle adjuvants, as well as delivery platforms. Periodontal diseases are the most prevalent oral diseases in humans and have serious health and economic burdens, greatly reducing quality of life. The aim of this study is to investigate the humoral immune responses to an OMV-based periodontal disease vaccine in beagles. The vaccine elicited strong mucosal immune responses when administered to beagles by a four-dose heterologous immunization (IN-IN-IN prime and subcutaneous [SC] boost). The OMV vaccine significantly altered the composition of the microbial community in the oral cavity. These findings suggest the utility of the intranasal (IN) prime followed by the SC boost regimen as a rational option to elicit robust humoral immune responses in canines, and most probably in humans as well. We here discuss the outcomes of beagle experiments, the mechanism behind immunological escape of Pg from host immunity, and a rational perspective toward sterilizing immunity in the oral cavity.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0103324"},"PeriodicalIF":3.7,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12039265/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657432","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":"Simple growth conditions improve targeted gene deletion in <i>Cryptococcus neoformans</i>.","authors":"Rebekah G Watson, Camaron R Hole","doi":"10.1128/msphere.01070-24","DOIUrl":"10.1128/msphere.01070-24","url":null,"abstract":"<p><p><i>Cryptococcus neoformans</i> infections are a significant cause of morbidity and mortality among AIDS patients and the third most common invasive fungal infection in organ transplant recipients. The cryptococcal cell wall is very dynamic and can be modulated depending on growth conditions. It was reported that when <i>C. neoformans</i> is grown in unbuffered yeast nitrogen base (YNB) for 48 hours, the pH of the media drastically drops, and the cells start to shed their cell walls. With this observation, we sought to determine if YNB-grown cells could be used directly for genetic transformation. To test this, we targeted <i>ADE2</i> using TRACE (transient CRISPR-Cas9 coupled with electroporation) in YNB-grown or competent cells. Deletion of the <i>ADE2</i> gene results in red-pigmented colonies, allowing visual confirmation of disruption. We were able to successfully delete <i>ADE2</i> in YNB-grown cells with better efficiency compared to competent cells. Recent studies have shown that gene deletion can be accomplished using short (50  bp) homology arms in place of the normal long arms (~1 kb). However, it was inefficient, leading to more insertions and gene disruption than gene deletions. We tested short homology with YNB-grown cells vs. competent cells and found that gene deletion was significantly improved in YNB-grown cells, at around 60% compared to 6% in competent cells. This was also observed when we deleted <i>LAC1</i> with the short arms. Altogether, using simple growth conditions, we have greatly improved the speed and efficiency of cryptococcal genetic transformations.IMPORTANCEThe World Health Organization recently ranked <i>C. neoformans</i> as the highest-priority fungal pathogen based on unmet research and development needs and its public health importance. Understanding cryptococcal pathogenicity is key for developing treatments. We found that using simple growth conditions can greatly improve the speed and efficiency of cryptococcal genetic transformations. This finding will advance the field by expanding the ease of cryptococcal genetic manipulations.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0107024"},"PeriodicalIF":3.7,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12039239/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764470","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}