mSphere最新文献

{"title":"Diversity of <i>Campylobacter</i> spp. circulating in a rhesus macaque (<i>Macaca mulatta</i>) breeding colony using culture and molecular methods.","authors":"Rebecca L Bacon, Carolyn L Hodo, Jing Wu, Shannara Welch, Colette Nickodem, Javier Vinasco, Deborah Threadgill, Stanton B Gray, Keri N Norman, Sara D Lawhon","doi":"10.1128/msphere.00560-24","DOIUrl":"10.1128/msphere.00560-24","url":null,"abstract":"&lt;p&gt;&lt;p&gt;&lt;i&gt;Campylobacter jejuni&lt;/i&gt; and &lt;i&gt;Campylobacter coli&lt;/i&gt; represent the leading causes of bacterial gastroenteritis in humans, and infections can produce post-infectious irritable bowel syndrome (PI-IBS). Rhesus macaques (&lt;i&gt;Macaca mulatta&lt;/i&gt;) (RM) are similarly susceptible to acute campylobacteriosis and represent a potential model of PI-IBS. We characterized the &lt;i&gt;Campylobacter&lt;/i&gt; species circulating in an RM breeding colony using culture, qPCR, and whole genome sequencing (WGS). We also compared the &lt;i&gt;C. jejuni&lt;/i&gt; and &lt;i&gt;C. coli&lt;/i&gt; prevalence in RM as detected with qPCR versus culture and identified risk factors for bacteria presence and intestinal disease. Culture of 275 samples yielded &lt;i&gt;C. coli&lt;/i&gt; (103) and &lt;i&gt;C. jejuni&lt;/i&gt; (8), of which 21.6% were resistant to quinolones and 3.6% were resistant to macrolides. Multidrug-resistant isolates were obtained exclusively from animals exhibiting diarrhea or with histologically confirmed chronic enterocolitis. WGS revealed a non-clonal population of &lt;i&gt;Campylobacter&lt;/i&gt; spp. Genotypic predictions of resistance were excellent except for aminoglycosides. All sequenced isolates contained genes for all subunits of cytolethal distending toxin. qPCR detected a prevalence of 45.9% for &lt;i&gt;C. coli&lt;/i&gt; and 29.6% for &lt;i&gt;C. jejuni&lt;/i&gt;. The quantity of either bacteria was significantly higher (&lt;i&gt;P&lt;/i&gt; &lt; 0.05) in animals with intestinal disease compared to healthy animals, though only young age was significantly associated with the presence of &lt;i&gt;Campylobacter&lt;/i&gt; sp. or intestinal disease. Significantly more &lt;i&gt;C. jejuni&lt;/i&gt; positive animals were detected with qPCR than with culture. These results provide a comprehensive characterization of &lt;i&gt;Campylobacter&lt;/i&gt; spp. circulating in a breeding colony of RM in the United States and suggest that qPCR is superior for the detection of &lt;i&gt;C. jejuni&lt;/i&gt; in RM.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Importance: &lt;/strong&gt;Gastrointestinal disease is one of the most common reasons for hospitalization in non-human primate colonies and accounts for over one-third of non-research related euthanasia. In rhesus macaques, this manifests as both acute diarrhea and chronic enterocolitis (CE), a syndrome of chronic diarrhea resulting in poor weight gain or weight loss which is minimally responsive to treatment. &lt;i&gt;Campylobacter&lt;/i&gt; spp. are major causes of acute enterocolitis in rhesus macaques and may predispose individuals to the development of CE, similar to post-infectious irritable bowel syndrome in humans. Despite these concerns, there are few studies characterizing &lt;i&gt;Campylobacter&lt;/i&gt; in rhesus macaque colonies, in particular utilizing whole genome sequencing and assessing findings with respect to the health status of the host. Our findings provide insight into &lt;i&gt;Campylobacter&lt;/i&gt; strains circulating in rhesus macaque colonies, which can improve clinical monitoring, assist in treatment decisions, and provide new avenues of investigation into campylobacteriosis as a catalyst for CE.&lt;/","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0056024"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580467/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504669","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":"Insights into human norovirus cultivation in human intestinal enteroids.","authors":"Khalil Ettayebi, Gurpreet Kaur, Ketki Patil, Janam Dave, B Vijayalakshmi Ayyar, Victoria R Tenge, Frederick H Neill, Xi-Lei Zeng, Allison L Speer, Sara C Di Rienzi, Robert A Britton, Sarah E Blutt, Sue E Crawford, Sasirekha Ramani, Robert L Atmar, Mary K Estes","doi":"10.1128/msphere.00448-24","DOIUrl":"10.1128/msphere.00448-24","url":null,"abstract":"<p><p>Human noroviruses (HuNoVs) are a significant cause of epidemic and sporadic acute gastroenteritis worldwide. The lack of a reproducible culture system hindered the study of HuNoV replication and pathogenesis for almost a half-century. This barrier was overcome with our successful cultivation of multiple HuNoV strains in human intestinal enteroids (HIEs), which has significantly advanced HuNoV research. We optimized culture media conditions and generated genetically modified HIE cultures to enhance HuNoV replication in HIEs. Building upon these achievements, we now present new insights into this culture system, which involve testing different media, unique HIE lines, and additional virus strains. HuNoV infectivity was evaluated and compared in new HIE models, including HIEs generated from different intestinal segments of individual adult organ donors, HIEs from human intestinal organoids produced from directed differentiation of human embryonic stem cells that were then transplanted and matured in mice before making enteroids (H9tHIEs), genetically engineered (J4<i>FUT2</i> knock-in [<i>KI</i>]<i>,</i> J2<i>STAT1</i> knockout [<i>KO</i>]) HIEs, as well as HIEs derived from a patient with common variable immunodeficiency (CVID) and from infants. Our findings reveal that small intestinal HIEs, but not colonoids, from adults, H9tHIEs, HIEs from a CVID patient, and HIEs from infants support HuNoV replication with segment and strain-specific differences in viral infection. J4<i>FUT2-KI</i> HIEs exhibit the highest susceptibility to HuNoV infection, allowing the cultivation of a broader range of genogroup I and II HuNoV strains than previously reported. Overall, these results contribute to a deeper understanding of HuNoVs and highlight the transformative potential of HIE cultures in HuNoV research.<b>IMPORTANCE</b>Human noroviruses (HuNoVs) cause global diarrheal illness and chronic infections in immunocompromised patients. This paper reports approaches for cultivating HuNoVs in secretor positive human intestinal enteroids (HIEs). HuNoV infectivity was compared in new HIE models, including ones from (i) different intestinal segments of single donors, (ii) human embryonic stem cell-derived organoids transplanted into mice, (iii) genetically modified lines, and (iv) a patient with common variable immunodeficiency disease. HIEs from small intestine, but not colon, support HuNoV replication with donor, segment, and strain-specific variations. Unexpectedly, HIEs from one donor are resistant to GII.3 infection. The genetically modified J4<i>FUT2</i> knock-in (<i>KI</i>) HIEs enable cultivation of a broad range of GI and GII genotypes. New insights into strain-specific differences in HuNoV replication in HIEs support this platform for advancing understanding of HuNoV biology and developing potential therapeutics.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0044824"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580437/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142470811","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":"Structured reviews pilot in <i>mSphere</i>.","authors":"Michael J Imperiale","doi":"10.1128/msphere.00847-24","DOIUrl":"10.1128/msphere.00847-24","url":null,"abstract":"","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0084724"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580444/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504672","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":"Circulating extracellular vesicles from severe COVID-19 patients induce lung inflammation.","authors":"Huifeng Qian, Ruoxi Zang, Ruoyang Zhang, Guoping Zheng, Guanguan Qiu, Jianbiao Meng, Jiangmei Wang, Jie Xia, Ruoqiong Huang, Zhenkai Le, Qiang Shu, Jianguo Xu","doi":"10.1128/msphere.00764-24","DOIUrl":"10.1128/msphere.00764-24","url":null,"abstract":"<p><p>Circulating extracellular vesicles (EVs) have been associated with the development of COVID-19 due to their roles in viral infection, inflammatory response, and thrombosis. However, the direct induction of lung inflammation by circulating EVs from severe COVID-19 patients remains unknown. EVs were extracted from the plasma of severe COVID-19 patients admitted to intensive care and healthy controls. To study the effect of COVID-19 EVs on lung inflammation, mice were intratracheally instilled with EVs. To examine the proinflammatory effects of EVs <i>in vitro</i>, bone marrow-derived macrophages were treated with EVs. COVID-19 but not control EVs triggered lung inflammation, as assessed by total protein level, total cell count, neutrophil count, and levels of proinflammatory cytokines in the bronchoalveolar lavage. COVID-19 EVs also promoted M1 polarization of alveolar macrophages <i>in vivo</i>. Treatment of bone marrow-derived macrophages with COVID-19 EVs enhanced the M1 phenotype and augmented the production of IL-1β, IL-6, and TNF-α. In summary, circulating EVs from severe COVID-19 patients induce lung inflammation in mice. EVs could become a potential therapeutic target for alleviating lung injury in COVID-19.</p><p><strong>Importance: </strong>Extracellular vesicles (EVs) have been reported to facilitate cytokine storm, coagulation, vascular dysfunction, and the spread of the virus in COVID-19. The direct role of circulating EVs from severe COVID-19 patients in lung injury remains unrecognized. Our study demonstrated that plasma EVs obtained from severe COVID-19 patients induced lung inflammation and polarization of alveolar macrophages <i>in vivo</i>. <i>In vitro</i> experiments also revealed the proinflammatory effects of COVID-19 EVs. The present study sheds fresh insight into the mechanisms of COVID-19-induced lung injury, highlighting EVs as a potential therapeutic target in combating the disease.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0076424"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580465/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546504","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":"Strain variation in <i>Candida albicans</i> glycolytic gene regulation.","authors":"Min-Ju Kim, Amelia M White, Aaron P Mitchell","doi":"10.1128/msphere.00579-24","DOIUrl":"10.1128/msphere.00579-24","url":null,"abstract":"<p><p>Central carbon metabolism is vital for the proliferation of <i>Candida albicans</i>, a fungus that is prominent as a commensal and pathogen. Glycolytic genes are activated by overlapping activities of the transcription factors Tye7 and Gal4, as shown by studies in the SC5314 genetic background. However, regulatory relationships can vary among <i>C. albicans</i> isolates. Here, we analyzed Tye7- and Gal4-related phenotypes in five diverse clinical isolates of <i>C. albicans</i>. We tested growth properties and gene expression impact through Nanostring profiling and, for the two strains SC5314 and P87, RNA sequencing. Our results lead to three main conclusions. First, the functional redundancy of Tye7 and Gal4 for glycolytic gene activation is preserved among all strains tested. Second, at the gene expression level, strain P87 is an outlier with regard to <i>tye7</i>Δ/Δ impact, and strain SC5314 is an outlier with regard to <i>gal4</i>Δ/Δ impact. Third, while Gal4 is well known to be dispensable for induction of the <i>GAL1</i>, <i>GAL7</i>, and <i>GAL10</i> galactose-specific metabolic genes, we find that <i>gal4</i>Δ/Δ mutants of several strains have a mild galactose fermentation defect, as assayed by growth on galactose with the respiration inhibitor antimycin A. Our findings indicate that even a central metabolic regulatory network is subject to strain variation and illustrates an unexpected genotype-phenotype relationship.The fungal commensal and pathogen <i>Candida albicans</i> rely upon metabolic flexibility to colonize and infect host niches. Central carbon metabolism is governed by two regulators, Tye7 and Gal4, as defined in the reference strain SC5314. Here, we have explored the impact of Tye7 and Gal4 on carbon utilization and gene expression across five diverse <i>C. albicans</i> clinical isolates. Novel aspects of this study are the finding that even a central metabolic regulatory network is subject to strain variation and the observation of an unexpected mutant phenotype.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0057924"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580466/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142470717","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 putative type 4 secretion system effector BspD is involved in maintaining envelope integrity of the pathogen <i>Brucella</i>.","authors":"Maren Ketterer, Petra Chiquet, Mara Esposito, Jaroslaw Sedzicki, Maxime Québatte, Christoph Dehio","doi":"10.1128/msphere.00232-24","DOIUrl":"10.1128/msphere.00232-24","url":null,"abstract":"<p><p>Brucellosis is a debilitating disease caused by the Gram-negative, facultative intracellular zoonotic pathogen <i>Brucella.</i> En route to its intracellular replicative niche, <i>Brucella</i> encounters various stressful environments that may compromise envelope integrity. Here we show that the proposed type 4 secretion system (T4SS) effector BspD is a conserved protein of the Rhizobiales, which does not show signs of co-evolution with the presence of a T4SS or a certain lifestyle. We further present data indicating that BspD is critical for the envelope integrity of <i>Brucella abortus</i> in the stationary phase and in the presence of EDTA, a compound known to destabilize the outer membrane. Deletion of <i>bspD</i> resulted in abnormal bacterial morphologies, indicating its involvement in maintaining envelope integrity. Additionally, the absence of BspD led to the formation of fewer and smaller intracellular microcolonies in a macrophage infection model. From our observations, we propose that BspD of <i>B. abortus</i> is critical for preserving the integrity of the bacterial envelope, particularly under stressful conditions, which may enhance <i>Brucella</i>'s ability to survive within host cells.</p><p><strong>Importance: </strong>Brucellosis, caused by the intracellular pathogen <i>Brucella</i>, poses a significant health threat. Understanding how <i>Brucella</i> adapts to stressful environments is crucial. This study unveils BspD, a conserved protein within the Rhizobiales order, as a key player in maintaining <i>Brucella</i>'s envelope integrity. Remarkably, BspD's presence within the Rizobiales appears independent of the presence of a T4SS or a specific lifestyle. Deletion of <i>bspD</i> resulted in compromised envelope integrity, abnormal bacterial morphologies, and reduced intracellular microcolony formation. These findings underscore BspD's critical role, particularly in stressful conditions like the stationary phase and EDTA exposure, and highlight its significance for the survival of <i>Brucella</i> within host cells. This elucidation deepens our understanding of <i>Brucella</i> pathogenesis and may inform future therapeutic strategies against brucellosis.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0023224"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580434/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142470718","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":"<i>Burkholderia pseudomallei</i> BopE suppresses the Rab32-dependent defense pathway to promote its intracellular replication and virulence.","authors":"Chenglong Rao, Ziyuan Zhang, Jianpeng Qiao, Dongqi Nan, Pan Wu, Liting Wang, Changhao Yao, Senquan Zheng, Jinzhu Huang, Yaling Liao, Wenzheng Liu, Zhiqiang Hu, Shiwei Wang, Yuan Wen, Jingmin Yan, Xuhu Mao, Qian Li","doi":"10.1128/msphere.00453-24","DOIUrl":"10.1128/msphere.00453-24","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Melioidosis is a serious infectious disease caused by the Gram-negative bacterium &lt;i&gt;Burkholderia pseudomallei&lt;/i&gt;. Recently, Rab32-dependent immune vesicles emerge as a critical defense pathway to restrict the intracellular &lt;i&gt;B. pseudomallei&lt;/i&gt;. However, &lt;i&gt;B. pseudomallei&lt;/i&gt; can evade host immune vesicles and survive in the cytoplasm, although this mechanism is not well understood. In this study, we found Rab32-dependent vesicles could effectively combat &lt;i&gt;B. pseudomallei&lt;/i&gt; infection, but not all intracellular &lt;i&gt;B. pseudomallei&lt;/i&gt; were encapsulated in Rab32-positive vesicles. To explore how &lt;i&gt;B. pseudomallei&lt;/i&gt; counteracted the Rab32-dependent defense pathway, transcriptomic profiling of &lt;i&gt;B. pseudomallei&lt;/i&gt; was performed to characterize the response dynamics during infection. We found that the type III secretion system of &lt;i&gt;B. pseudomallei&lt;/i&gt; was activated, and a variety of effector proteins were highly upregulated. Among them, BopE, BprD, and BipC were shown to interact with Rab32. Interestingly, BopE directly interacts with host Rab32, potentially suppressing Rab32 function by interfering with nucleotide exchange, which in turn restricts the recruitment of Rab32 to bacterial-containing vesicles. Knocking out of BopE can increase the proportion of Rab32-positive vesicles, suppressing the intracellular replication and virulence of &lt;i&gt;B. pseudomallei&lt;/i&gt;. Collectively, our findings have demonstrated that BopE may be an important effector for &lt;i&gt;B. pseudomallei&lt;/i&gt; to evade from the Rab32-dependent killing vesicles into the cytosol for survival and replication. Therefore, a deeper understanding of the interaction between BopE and the host Rab32-dependent restriction pathway may provide an effective therapeutic strategy for the elimination of intracellular &lt;i&gt;B. pseudomallei&lt;/i&gt;.IMPORTANCE&lt;i&gt;B. pseudomallei&lt;/i&gt; is facultative intracellular bacterium that has evolved numerous strategies to evade host immune vesicles and survive in the cytoplasm. Rab32-dependent vesicles are one of these immune vesicles, but the mechanism by which &lt;i&gt;B. pseudomallei&lt;/i&gt; escape Rab32-dependent vesicles remains elusive. Here, we find &lt;i&gt;B. pseudomallei&lt;/i&gt; infection leading the activation of the type III secretion system (T3SS-3) and increasing the expression of various effectors. Specifically, we identify that BopE, an effector secreted by T3SS-3, triggers vesicle escape to promote &lt;i&gt;B. pseudomallei&lt;/i&gt; pathogenicity and survival. Mechanistically, BopE suppresses the activation of Rab32 by interfering with nucleotide exchange, ultimately triggering vesicle escape and intracellular survival. We also find knocking out the &lt;i&gt;bopE&lt;/i&gt; gene can increase the proportion of Rab32-positive vesicles that trap &lt;i&gt;B. pseudomallei&lt;/i&gt;, dampening the survival of &lt;i&gt;B. pseudomallei&lt;/i&gt; both &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt;. Taken together, our findings provide insights into the molecular mechanisms of pathogen effector-induced vesicle escape, indicating a p","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0045324"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580396/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142470805","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":"Kinase function of TgTKL1 is essential for its role in <i>Toxoplasma</i> propagation and pathogenesis.","authors":"Dima Hajj Ali, Ramu Anandakrishnan, Vern B Carruthers, Rajshekhar Y Gaji","doi":"10.1128/msphere.00779-24","DOIUrl":"10.1128/msphere.00779-24","url":null,"abstract":"<p><p>The Tyrosine Kinase-Like (TKL) family of proteins are a set of poorly studied kinases that have garnered attention in recent years for their role in <i>Toxoplasma</i> biology. The <i>Toxoplasma</i> genome contains eight TKL kinases, of which six have been predicted to be important for parasite propagation. We have previously shown that TgTKL1 is a nuclear kinase that is critical for the parasite lytic cycle and is essential for acute virulence in the animal model. However, the contribution of the kinase domain to the functioning of TgTKL1 was not known. Hence to determine the significance of its catalytic function, we first validated that TgTKL1 is a true kinase using purified recombinant protein. Furthermore, we successfully generated a TgTKL1 kinase mutant strain of <i>Toxoplasma</i> via CRISPR-Cas9 gene editing. Our studies revealed that the kinase mutant of TgTKL1 displays defects in parasite growth and host-cell invasion. Additionally, loss of kinase function alters the transcriptomic profile of the parasite, including downregulation of the invasion-related gene, TgSUB1. Importantly, this dysregulation of TgSUB1 expression leads to defects in post-exocytosis processing of micronemal proteins, an event critical for normal host-cell invasion. Furthermore, the TgTKL1 kinase mutant is completely avirulent in the mouse model of acute toxoplasmosis. Since the loss of kinase function leads to phenotypic manifestations seen previously with TgTKL1 knockout parasites, we conclude that kinase activity is important for TgTKL1 function in <i>Toxoplasma</i> propagation and virulence.</p><p><strong>Importance: </strong><i>Toxoplasma gondii</i> is a protozoan parasite that can cause life-threatening disease in humans. Hence, identifying key factors required for parasite growth and pathogenesis is important to develop novel therapeutics. We have previously shown that a member of the TKL protein kinase family, TgTKL1, is a plant-like kinase that is required for effective Toxoplasma growth <i>in vitro</i> and essential for virulence <i>in vivo</i>. Herein, we show that the TgTKL1 is, indeed, a <i>bona fide</i> kinase, and loss of its kinase function in the Toxoplasma leads to similar defects seen in parasites with complete loss of TgTKL1. More specifically, the TgTKL1 kinase mutant exhibits defects in parasite growth, host-cell invasion, gene expression profile, and virulence in the animal model. Together, these findings suggest that TgTKL1 is a true kinase, and loss of its kinase activity leads to disruption of TgTKL1 function in <i>Toxoplasma</i>.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0077924"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580469/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546509","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 promiscuous biotin ligase TurboID reveals the proxisome of the T3SS chaperone IpgC in <i>Shigella flexneri</i>.","authors":"Nathaline Haidar-Ahmad, Kyle Tomaro, Mathieu Lavallée-Adam, François-Xavier Campbell-Valois","doi":"10.1128/msphere.00553-24","DOIUrl":"10.1128/msphere.00553-24","url":null,"abstract":"<p><p>Promiscuous biotin ligases derived from the bacterial enzyme BirA are used to identify proteins vicinal to a bait protein, thereby defining its proxisome. Despite the popularity of this approach, surprisingly little is known about its use in prokaryotes. Here, we compared the activity of four widely used promiscuous biotin ligases in the cytoplasm of <i>Shigella flexneri</i>, a pathogenic subgroup of <i>Escherichia coli</i>. Our data indicate that the kinetics of TurboID's biotinylating activity is the highest of those tested. In addition, TurboID showed reduced interaction with the natural BirA binding partners, BccP and the biotin operator, when compared to its ancestor BioID. We therefore evaluated the ability of TurboID to probe the proxisome of the type III secretion system (T3SS) chaperone IpgC and the transcriptional activator MxiE. When the T3SS is inactive (off-state), these proteins are inhibited by forming complexes with the T3SS substrates OspD1 and IpaBC, respectively. In contrast, when the T3SS is active (on-state), OspD1 and IpaBC are secreted allowing MxiE and IpgC to interact together and activate their target genes. The results obtained with the IpgC and TurboID fusions capture a good fraction of these known interactions. It also suggests that the availability of IpgC increases in the on-state, resulting in a greater number of proteins detected in its vicinity. Among these is the T3SS ATPase SpaL (also known as Spa47 or SctN), further supporting the notion that chaperones escort their substrate to the T3SS. Interestingly, a specific subset of proteins conserved in <i>E. coli</i> completes the IpgC proxisome in the on-state.IMPORTANCEPromiscuous biotin ligases are widely used to study protein function in eukaryotes. Strikingly, their use in prokaryotes has been rare. Indeed, the small volume and the cytoplasmic location of the biotin ligase's natural binding partners in these organisms pose unique challenges that can interfere with the study of the proxisome of proteins of interest. Here, we evaluated four of the most common promiscuous biotin ligases and found TurboID was best suited for use in the cytoplasm of <i>Shigella flexneri</i>. Using this method, we extended the proxisome of IpgC beyond its known direct binding partners involved in the regulation of the type III secretion system (T3SS) signaling cascade. Of particular interest for further study are transcription factors and housekeeping proteins that are enriched around IpgC when the T3SS is active. We propose a model in which the increased availability of IpgC in the on-state may allow cross-talk of the T3SS with other cellular processes.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0055324"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580435/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546510","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":"First insights into the prevalence, genetic characteristics, and pathogenicity of <i>Bacillus cereus</i> from generations worldwide.","authors":"Cuihong Tong, Danyu Xiao, Qi Li, Jing Gou, Shuang Wang, Zhenling Zeng, Wenguang Xiong","doi":"10.1128/msphere.00702-24","DOIUrl":"10.1128/msphere.00702-24","url":null,"abstract":"<p><p><i>Bacillus cereus</i>, a global threat, is one of the major causes of toxin-induced foodborne diseases. However, a comprehensive assessment of the prevalence and characteristics of <i>B. cereus</i> worldwide is still lacking. Here, we applied whole-genome sequence analysis to 191 <i>B. cereus</i> collected in Africa, America, Asia, Europe, and Oceania from the 1900s to 2022, finding that CC142 dominated the global <i>B. cereus</i> clonal complex. The results provided direct evidence that <i>B. cereus</i> could spread through the food chain and intercontinentally. <i>B. cereus</i> from different generations worldwide showed coherence in the antibiotic-resistant gene and virulence and biofilm gene profiles, although with high genomic heterogeneity. The <i>BCI-BCII-vanZF-fosB</i> profiles and virulence and biofilm genes were detected at high rates, and we emphasized that <i>B. cereus</i> would pose a serious challenge to global public health and clinical treatment.IMPORTANCEThis study first emphasized the prevalence, genetic characteristics, and pathogenicity of <i>Bacillus cereus</i> worldwide from the 1900s to 2022 using whole-genome sequence analysis. The CC142 dominated the global <i>Bacillus cereus</i> clonal complex. Moreover, we revealed a close evolutionary relationship between the isolates from different sources. <i>B. cereus</i> isolates from different generations worldwide showed coherence in potential pathogenicity, although with high genomic heterogeneity. The <i>BCI-BCII-vanZF-fosB</i> profiles and virulence and biofilm genes were detected at high rates, and we emphasized that <i>B. cereus</i> would pose a serious challenge to global public health and clinical treatment.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0070224"},"PeriodicalIF":3.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580406/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504671","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}