Chromosome segregation in bacteria is a critical process ensuring that each daughter cell receives an accurate copy of the genetic material during cell division. Active segregation factors, such as the ParABS system or SMC complexes, are usually essential for this process, but they are surprisingly dispensable in Streptococcus pneumoniae. Rather, chromosome segregation in S. pneumoniae relies on the protein Regulator of Chromosome Segregation (RocS), although the molecular mechanisms involved remain elusive. By combining genetics, in vivo imaging, and biochemical approaches, we dissected the molecular features of RocS involved in chromosome segregation. We investigated the respective functions of the three RocS domains, specifically the C-terminal amphipathic helix (AH), the N-terminal DNA-binding domain (DBD), and the coiled-coil domain (CCD) separating the AH and the DBD. Notably, we found that a single AH is not sufficient for membrane binding and that RocS requires prior oligomerization to interact with the membrane. We further demonstrated that this self-interaction was driven by the N-terminal part of the CCD. On the other hand, we revealed that the C-terminal part of the CCD corresponds to a domain of unknown function (DUF 536) and is defined by three conserved glutamines, which play a crucial role in RocS-mediated chromosome segregation. Finally, we showed that the DBD is phosphorylated by the unique serine-threonine kinase of S. pneumoniae StkP and that mimicking this phosphorylation abrogated RocS binding to DNA. Overall, this study offers new insights into chromosome segregation in Streptococci and paves the way for a deeper understanding of RocS-like proteins in other bacteria.IMPORTANCEBacteria have evolved a variety of mechanisms to properly segregate their genetic material during cell division. In this study, we performed a molecular dissection of the chromosome partitioning protein Regulator of Chromosome Segregation (RocS), a pillar element of chromosome segregation in S. pneumoniae that is also generally conserved in the Streptococcaceae family. Our systematic investigation sheds light on the molecular features required for successful pneumococcal chromosome segregation and the regulation of RocS by phosphorylation. In addition, our study also revealed that RocS shares functional domains with the Par protein, involved in an atypical plasmid segregation system. Therefore, we expect that our findings may serve to extend our understanding of RocS and RocS-like proteins while broadening the repertoire of partitioning systems used in bacteria.
细菌中的染色体分离是一个关键过程,可确保每个子细胞在细胞分裂过程中获得准确的遗传物质拷贝。活性分离因子(如 ParABS 系统或 SMC 复合物)通常对这一过程至关重要,但令人惊讶的是,肺炎链球菌中的这些因子却可有可无。相反,肺炎链球菌的染色体分离依赖于染色体分离调节蛋白(RocS),但其中涉及的分子机制仍然难以捉摸。通过结合遗传学、体内成像和生化方法,我们剖析了 RocS 参与染色体分离的分子特征。我们研究了 RocS 三个结构域各自的功能,特别是 C 端两亲螺旋(AH)、N 端 DNA 结合结构域(DBD)以及分隔 AH 和 DBD 的盘绕结构域(CCD)。值得注意的是,我们发现单个 AH 并不足以与膜结合,RocS 需要事先寡聚化才能与膜相互作用。我们进一步证明,这种自我相互作用是由 CCD 的 N 端部分驱动的。另一方面,我们揭示了 CCD 的 C 端部分对应于一个未知功能域(DUF 536),由三个保守的谷氨酸定义,它们在 RocS 介导的染色体分离中起着至关重要的作用。最后,我们发现 DBD 被肺炎双球菌 StkP 独特的丝氨酸-苏氨酸激酶磷酸化,模拟这种磷酸化会减弱 RocS 与 DNA 的结合。总之,这项研究为链球菌的染色体分离提供了新的见解,并为深入了解其他细菌中的 RocS 类似蛋白铺平了道路。 重要意义细菌进化出了多种机制,在细胞分裂过程中正确分离遗传物质。在这项研究中,我们对染色体分离蛋白染色体分离调节器(RocS)进行了分子剖析。RocS是肺炎双球菌染色体分离的支柱元件,在链球菌家族中也普遍保守。我们的系统研究揭示了肺炎球菌染色体成功分离所需的分子特征,以及磷酸化对 RocS 的调控。此外,我们的研究还发现,RocS 与参与非典型质粒分离系统的 Par 蛋白共享功能域。因此,我们希望我们的研究结果能有助于扩展我们对 RocS 和 RocS 类似蛋白的了解,同时扩大细菌中使用的分离系统的范围。
{"title":"Molecular dissection of the chromosome partitioning protein RocS and regulation by phosphorylation.","authors":"Margaux Demuysere, Adrien Ducret, Christophe Grangeasse","doi":"10.1128/jb.00291-24","DOIUrl":"https://doi.org/10.1128/jb.00291-24","url":null,"abstract":"<p><p>Chromosome segregation in bacteria is a critical process ensuring that each daughter cell receives an accurate copy of the genetic material during cell division. Active segregation factors, such as the ParABS system or SMC complexes, are usually essential for this process, but they are surprisingly dispensable in <i>Streptococcus pneumoniae</i>. Rather, chromosome segregation in <i>S. pneumoniae</i> relies on the protein Regulator of Chromosome Segregation (RocS), although the molecular mechanisms involved remain elusive. By combining genetics, <i>in vivo</i> imaging, and biochemical approaches, we dissected the molecular features of RocS involved in chromosome segregation. We investigated the respective functions of the three RocS domains, specifically the C-terminal amphipathic helix (AH), the N-terminal DNA-binding domain (DBD), and the coiled-coil domain (CCD) separating the AH and the DBD. Notably, we found that a single AH is not sufficient for membrane binding and that RocS requires prior oligomerization to interact with the membrane. We further demonstrated that this self-interaction was driven by the N-terminal part of the CCD. On the other hand, we revealed that the C-terminal part of the CCD corresponds to a domain of unknown function (DUF 536) and is defined by three conserved glutamines, which play a crucial role in RocS-mediated chromosome segregation. Finally, we showed that the DBD is phosphorylated by the unique serine-threonine kinase of <i>S. pneumoniae</i> StkP and that mimicking this phosphorylation abrogated RocS binding to DNA. Overall, this study offers new insights into chromosome segregation in Streptococci and paves the way for a deeper understanding of RocS-like proteins in other bacteria.IMPORTANCEBacteria have evolved a variety of mechanisms to properly segregate their genetic material during cell division. In this study, we performed a molecular dissection of the chromosome partitioning protein Regulator of Chromosome Segregation (RocS), a pillar element of chromosome segregation in <i>S. pneumoniae</i> that is also generally conserved in the <i>Streptococcaceae</i> family. Our systematic investigation sheds light on the molecular features required for successful pneumococcal chromosome segregation and the regulation of RocS by phosphorylation. In addition, our study also revealed that RocS shares functional domains with the Par protein, involved in an atypical plasmid segregation system. Therefore, we expect that our findings may serve to extend our understanding of RocS and RocS-like proteins while broadening the repertoire of partitioning systems used in bacteria.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-22DOI: 10.1128/jb.00227-24
Zachary A Taylor, Ping Chen, Payam Noeparvar, Danniel N Pham, Alejandro R Walker, Todd Kitten, Lin Zeng
As a biological byproduct from both humans and microbes, glycerol's contribution to microbial homeostasis in the oral cavity remains understudied. In this study, we examined glycerol metabolism by Streptococcus sanguinis, a commensal associated with oral health. Genetic mutants of glucose-PTS enzyme II (manL), glycerol metabolism (glp and dha pathways), and transcriptional regulators were characterized with regard to glycerol catabolism, growth, production of hydrogen peroxide (H2O2), transcription, and competition with Streptococcus mutans. Biochemical assays identified the glp pathway as a novel source for H2O2 production by S. sanguinis that is independent of pyruvate oxidase (SpxB). Genetic analysis indicated that the glp pathway requires glycerol and a transcriptional regulator, GlpR, for expression and is negatively regulated by PTS, but not the catabolite control protein, CcpA. Conversely, deletion of either manL or ccpA increased the expression of spxB and a second, H2O2-non-producing glycerol metabolic pathway (dha), indicative of a mode of regulation consistent with conventional carbon catabolite repression (CCR). In a plate-based antagonism assay and competition assays performed with planktonic and biofilm-grown cells, glycerol greatly benefited the competitive fitness of S. sanguinis against S. mutans. The glp pathway appears to be conserved in several commensal streptococci and actively expressed in caries-free plaque samples. Our study suggests that glycerol metabolism plays a more significant role in the ecology of the oral cavity than previously understood. Commensal streptococci, though not able to use glycerol as a sole carbohydrate source for growth, benefit from the catabolism of glycerol through production of both ATP and H2O2.
Importance: Glycerol is an abundant carbohydrate in the oral cavity. However, little is understood regarding the metabolism of glycerol by commensal streptococci, some of the most abundant oral bacteria. This was in part because most streptococci cannot grow on glycerol as the sole carbon source. In this study, we show that Streptococcus sanguinis, a commensal associated with dental health, can degrade glycerol for persistence and competition through two pathways, one of which generates hydrogen peroxide at levels capable of inhibiting Streptococcus mutans. Preliminary studies suggest that several additional commensal streptococci are also able to catabolize glycerol, and glycerol-related genes are actively expressed in human dental plaque samples. Our findings reveal the potential of glycerol to significantly impact microbial homeostasis, which warrants further exploration.
{"title":"Glycerol metabolism contributes to competition by oral streptococci through production of hydrogen peroxide.","authors":"Zachary A Taylor, Ping Chen, Payam Noeparvar, Danniel N Pham, Alejandro R Walker, Todd Kitten, Lin Zeng","doi":"10.1128/jb.00227-24","DOIUrl":"10.1128/jb.00227-24","url":null,"abstract":"<p><p>As a biological byproduct from both humans and microbes, glycerol's contribution to microbial homeostasis in the oral cavity remains understudied. In this study, we examined glycerol metabolism by <i>Streptococcus sanguinis,</i> a commensal associated with oral health. Genetic mutants of glucose-PTS enzyme II (<i>manL</i>), glycerol metabolism (<i>glp</i> and <i>dha</i> pathways), and transcriptional regulators were characterized with regard to glycerol catabolism, growth, production of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), transcription, and competition with <i>Streptococcus mutans</i>. Biochemical assays identified the <i>glp</i> pathway as a novel source for H<sub>2</sub>O<sub>2</sub> production by <i>S. sanguinis</i> that is independent of pyruvate oxidase (SpxB). Genetic analysis indicated that the <i>glp</i> pathway requires glycerol and a transcriptional regulator, GlpR, for expression and is negatively regulated by PTS, but not the catabolite control protein, CcpA. Conversely, deletion of either <i>manL</i> or <i>ccpA</i> increased the expression of <i>spxB</i> and a second, H<sub>2</sub>O<sub>2</sub>-non-producing glycerol metabolic pathway (<i>dha</i>), indicative of a mode of regulation consistent with conventional carbon catabolite repression (CCR). In a plate-based antagonism assay and competition assays performed with planktonic and biofilm-grown cells, glycerol greatly benefited the competitive fitness of <i>S. sanguinis</i> against <i>S. mutans</i>. The <i>glp</i> pathway appears to be conserved in several commensal streptococci and actively expressed in caries-free plaque samples. Our study suggests that glycerol metabolism plays a more significant role in the ecology of the oral cavity than previously understood. Commensal streptococci, though not able to use glycerol as a sole carbohydrate source for growth, benefit from the catabolism of glycerol through production of both ATP and H<sub>2</sub>O<sub>2</sub>.</p><p><strong>Importance: </strong>Glycerol is an abundant carbohydrate in the oral cavity. However, little is understood regarding the metabolism of glycerol by commensal streptococci, some of the most abundant oral bacteria. This was in part because most streptococci cannot grow on glycerol as the sole carbon source. In this study, we show that <i>Streptococcus sanguinis</i>, a commensal associated with dental health, can degrade glycerol for persistence and competition through two pathways, one of which generates hydrogen peroxide at levels capable of inhibiting <i>Streptococcus mutans</i>. Preliminary studies suggest that several additional commensal streptococci are also able to catabolize glycerol, and glycerol-related genes are actively expressed in human dental plaque samples. Our findings reveal the potential of glycerol to significantly impact microbial homeostasis, which warrants further exploration.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411925/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142017521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-22DOI: 10.1128/jb.00004-24
Jingjun Lin, Sook Yin Chong, Myung Whan Oh, Shi Qian Lew, Luchang Zhu, Xuejin Zhang, William H Witola, Gee W Lau
Streptococcus pneumoniae (pneumococcus) causes a wide range of important human infectious diseases, including pneumonia, pneumonia-derived sepsis, otitis media, and meningitis. Pneumococcus produces numerous secreted proteins that are critical for normal physiology and pathogenesis. The membrane targeting and translocation of these secreted proteins are partly mediated by the signal recognition particle (SRP) complex, which consists of 4.5S small cytoplasmic RNA (ScRNA), and the Ffh, and FtsY proteins. Here, we report that pneumococcal ∆scRNA, ∆ffh, and ∆ftsY mutants were significantly impaired in competence induction, competence pili production, exogenous DNA uptake, and genetic transformation. Also, the ∆scRNA mutant was significantly attenuated in the mouse models of bacteremia and pneumonia. Interestingly, unlike the ∆scRNA, both ∆ffh and ∆ftsY mutants had growth defects on Todd-Hewitt Agar, which were alleviated by the provision of free amino acids or serum. Differences in nutritional requirements between ∆ffh and ∆ftsY vs ∆scRNA suggest that Ffh and FtsY may be partially functional in the absence of ScRNA. Finally, the insertase YidC2, which could functionally rescue some SRP mutations in other streptococcal species, was not essential for pneumococcal genetic transformation. Collectively, these results indicate that ScRNA is crucial for the successful development of genetic competence and virulence in pneumococcus.
Importance: Streptococcus pneumoniae (pneumococcus) causes multiple important infectious diseases in humans. The signal recognition particle (SRP) complex, which comprised 4.5S small cytoplasmic RNA (ScRNA), and the Ffh and FtsY proteins, mediates membrane targeting and translocation of secreted proteins in all organisms. However, the role of SRP and ScRNA has not been characterized during the induction of the competence system for genetic transformation and virulence in pneumococcus. By using a combination of genetic, biochemical, proteomic, and imaging approaches, we demonstrated that the SRP complex plays a significant role in membrane targeting of competence system-regulated effectors important for genetic transformation, virulence during bacteremia and pneumonia infections, and nutritional acquisition.
{"title":"Signal recognition particle RNA is critical for genetic competence and virulence of <i>Streptococcus pneumoniae</i>.","authors":"Jingjun Lin, Sook Yin Chong, Myung Whan Oh, Shi Qian Lew, Luchang Zhu, Xuejin Zhang, William H Witola, Gee W Lau","doi":"10.1128/jb.00004-24","DOIUrl":"10.1128/jb.00004-24","url":null,"abstract":"<p><p><i>Streptococcus pneumoniae</i> (pneumococcus) causes a wide range of important human infectious diseases, including pneumonia, pneumonia-derived sepsis, otitis media, and meningitis. Pneumococcus produces numerous secreted proteins that are critical for normal physiology and pathogenesis. The membrane targeting and translocation of these secreted proteins are partly mediated by the signal recognition particle (SRP) complex, which consists of 4.5S small cytoplasmic RNA (ScRNA), and the Ffh, and FtsY proteins. Here, we report that pneumococcal ∆<i>scRNA</i>, ∆<i>ffh,</i> and ∆<i>ftsY</i> mutants were significantly impaired in competence induction, competence pili production, exogenous DNA uptake, and genetic transformation. Also, the ∆<i>scRNA</i> mutant was significantly attenuated in the mouse models of bacteremia and pneumonia. Interestingly, unlike the ∆<i>scRNA</i>, both ∆<i>ffh</i> and ∆<i>ftsY</i> mutants had growth defects on Todd-Hewitt Agar, which were alleviated by the provision of free amino acids or serum. Differences in nutritional requirements between ∆<i>ffh</i> and ∆<i>ftsY</i> vs ∆<i>scRNA</i> suggest that Ffh and FtsY may be partially functional in the absence of ScRNA. Finally, the insertase YidC2, which could functionally rescue some SRP mutations in other streptococcal species, was not essential for pneumococcal genetic transformation. Collectively, these results indicate that ScRNA is crucial for the successful development of genetic competence and virulence in pneumococcus.</p><p><strong>Importance: </strong><i>Streptococcus pneumoniae</i> (pneumococcus) causes multiple important infectious diseases in humans. The signal recognition particle (SRP) complex, which comprised 4.5S small cytoplasmic RNA (ScRNA), and the Ffh and FtsY proteins, mediates membrane targeting and translocation of secreted proteins in all organisms. However, the role of SRP and ScRNA has not been characterized during the induction of the competence system for genetic transformation and virulence in pneumococcus. By using a combination of genetic, biochemical, proteomic, and imaging approaches, we demonstrated that the SRP complex plays a significant role in membrane targeting of competence system-regulated effectors important for genetic transformation, virulence during bacteremia and pneumonia infections, and nutritional acquisition.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11412328/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142017523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-19DOI: 10.1128/jb.00173-24
Brandon Robin, Amélie Dewitte, Véronique Alaimo, Cecile Lecoeur, François Pierre, Gabriel Billon, Florent Sebbane, Sébastien Bontemps-Gallo
The adaptation of Yersinia pestis, the flea-borne plague agent, to fluctuating environmental conditions is essential for the successful colonization of the flea vector. A previous comparative transcriptomic analysis showed that the Cpx pathway of Y. pestis is up-regulated in infected fleas. The CpxAR two-component system is a component of the envelope stress response and is critical for maintaining the integrity of the cell. Here, a phenotypic screening revealed a survival defect of the cpxAR mutant to oxidative stress and copper. The measured copper concentration in the digestive tract contents of fed fleas increased fourfold during the digestive process. By direct analysis of phosphorylation of CpxR by a Phos-Tag gel approach, we demonstrated that biologically relevant concentrations of copper triggered the system. Then, a competitive challenge highlighted the role of the CpxAR system in bacterial fitness during flea infection. Lastly, an in vitro sequential exposure to copper and then H2O2 to mimic the flea suggests a model in which, within the insect digestive tract, the CpxAR system would be triggered by copper, establishing an oxidative stress response.
Importance: The bacterium Yersinia pestis is the agent of flea-borne plague. Our knowledge of the mechanisms used by the plague bacillus to infect the flea vector is limited. The up-regulation of the envelope stress response under the control of the Cpx signaling pathway was previously shown in a transcriptomic study. Here, our in vivo and in vitro approaches suggest a model in which Y. pestis uses the CpxAR phosphorelay system to sense and respond to the copper present in the flea gut, thereby optimizing the flea gut colonization. In other words, the system is essential for bacterial fitness in the flea.
{"title":"The CpxAR signaling system confers a fitness advantage for flea gut colonization by the plague bacillus.","authors":"Brandon Robin, Amélie Dewitte, Véronique Alaimo, Cecile Lecoeur, François Pierre, Gabriel Billon, Florent Sebbane, Sébastien Bontemps-Gallo","doi":"10.1128/jb.00173-24","DOIUrl":"10.1128/jb.00173-24","url":null,"abstract":"<p><p>The adaptation of <i>Yersinia pestis</i>, the flea-borne plague agent, to fluctuating environmental conditions is essential for the successful colonization of the flea vector. A previous comparative transcriptomic analysis showed that the Cpx pathway of <i>Y. pestis</i> is up-regulated in infected fleas. The CpxAR two-component system is a component of the envelope stress response and is critical for maintaining the integrity of the cell. Here, a phenotypic screening revealed a survival defect of the <i>cpxAR</i> mutant to oxidative stress and copper. The measured copper concentration in the digestive tract contents of fed fleas increased fourfold during the digestive process. By direct analysis of phosphorylation of CpxR by a Phos-Tag gel approach, we demonstrated that biologically relevant concentrations of copper triggered the system. Then, a competitive challenge highlighted the role of the CpxAR system in bacterial fitness during flea infection. Lastly, an <i>in vitro</i> sequential exposure to copper and then H<sub>2</sub>O<sub>2</sub> to mimic the flea suggests a model in which, within the insect digestive tract, the CpxAR system would be triggered by copper, establishing an oxidative stress response.</p><p><strong>Importance: </strong>The bacterium <i>Yersinia pestis</i> is the agent of flea-borne plague. Our knowledge of the mechanisms used by the plague bacillus to infect the flea vector is limited. The up-regulation of the envelope stress response under the control of the Cpx signaling pathway was previously shown in a transcriptomic study. Here, our <i>in vivo</i> and <i>in vitro</i> approaches suggest a model in which <i>Y. pestis</i> uses the CpxAR phosphorelay system to sense and respond to the copper present in the flea gut, thereby optimizing the flea gut colonization. In other words, the system is essential for bacterial fitness in the flea.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411919/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141999929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-14DOI: 10.1128/jb.00116-24
Jeffrey S Bourgeois, Linden T Hu
Don't Panic. In the nearly 50 years since the discovery of Lyme disease, Borrelia burgdorferi has emerged as an unlikely workhorse of microbiology. Interest in studying host-pathogen interactions fueled significant progress in making the fastidious microbe approachable in laboratory settings, including the development of culture methods, animal models, and genetic tools. By developing these systems, insight has been gained into how the microbe is able to survive its enzootic cycle and cause human disease. Here, we discuss the discovery of B. burgdorferi and its development as a model organism before diving into the critical lessons we have learned about B. burgdorferi biology at pivotal stages of its lifecycle: gene expression changes during the tick blood meal, colonization of a new vertebrate host, and developing a long-lasting infection in that vertebrate until a new tick feeds. Our goal is to highlight the advancements that have facilitated B. burgdorferi research and identify gaps in our current understanding of the microbe.
不要惊慌自莱姆病被发现以来的近 50 年里,鲍氏不动杆菌已成为微生物学中一个不太可能的主力军。人们对研究宿主与病原体之间相互作用的兴趣推动了在实验室环境中接近这种难以捉摸的微生物方面取得的重大进展,包括培养方法、动物模型和基因工具的开发。通过开发这些系统,我们深入了解了这种微生物是如何在其流行周期中存活下来并引发人类疾病的。在这里,我们将讨论伯氏菌的发现及其作为模式生物的发展,然后深入探讨我们在伯氏菌生命周期的关键阶段所获得的生物学方面的重要经验:蜱虫血餐期间的基因表达变化、新脊椎动物宿主的定殖以及在新蜱虫进食之前在该脊椎动物体内形成持久感染。我们的目标是强调促进 B. burgdorferi 研究的进展,并找出我们目前对该微生物了解的不足之处。
{"title":"Hitchhiker's Guide to <i>Borrelia burgdorferi</i>.","authors":"Jeffrey S Bourgeois, Linden T Hu","doi":"10.1128/jb.00116-24","DOIUrl":"10.1128/jb.00116-24","url":null,"abstract":"<p><p>Don't Panic. In the nearly 50 years since the discovery of Lyme disease, <i>Borrelia burgdorferi</i> has emerged as an unlikely workhorse of microbiology. Interest in studying host-pathogen interactions fueled significant progress in making the fastidious microbe approachable in laboratory settings, including the development of culture methods, animal models, and genetic tools. By developing these systems, insight has been gained into how the microbe is able to survive its enzootic cycle and cause human disease. Here, we discuss the discovery of <i>B. burgdorferi</i> and its development as a model organism before diving into the critical lessons we have learned about <i>B. burgdorferi</i> biology at pivotal stages of its lifecycle: gene expression changes during the tick blood meal, colonization of a new vertebrate host, and developing a long-lasting infection in that vertebrate until a new tick feeds. Our goal is to highlight the advancements that have facilitated <i>B. burgdorferi</i> research and identify gaps in our current understanding of the microbe.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411949/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141975662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-23DOI: 10.1128/jb.00195-24
Liwei Fang, Chance Cosgriff, Francis Alonzo
The accessory gene regulatory (Agr) system is required for virulence factor gene expression and pathogenesis of Staphylococcus aureus. The Agr system is activated in response to the accumulation of a cyclic autoinducing peptide (AIP), which is matured and secreted by the bacterium. The precursor of AIP, AgrD, consists of the AIP flanked by an N-terminal [Formula: see text]-helical Leader and a charged C-terminal tail. AgrD is matured to AIP by the action of two proteases, AgrB and MroQ. AgrB cleaves the C-terminal tail and promotes the formation of a thiolactone ring, whereas MroQ cleaves the N-terminal Leader in a manner that depends on the four-amino acid linker immediately following a conserved IG helix breaker motif. However, the attributes of AgrD that dictate the sequence of events in peptide maturation are not fully defined. Here, we used engineered AgrD peptide intermediates to ascertain the sufficiency of MroQ for N-terminal peptide cleavage, peptide export, and generation of mature AIP. We found that MroQ promotes the removal of the N-terminal Leader peptide from both linear and cyclic peptide intermediates, while peptide cyclization remained essential for signaling. The expression of the Leader peptide in isolation was sufficient for MroQ-dependent cleavage proximal to the four-amino-acid linker. In addition, active site mutations within AgrB destabilized full-length AgrD and thiolactone-containing intermediates and prevented the release of the Leader peptide. Altogether, our data support a tandem peptide maturation event involving both MroQ and AgrB that appears to couple protease activity and export of bioactive AIP.IMPORTANCEThe accessory gene regulatory (Agr) system is important for S. aureus pathogenesis. Activation of the Agr system requires recognition of a cyclic peptide pheromone, which must be fully matured to exert its biological activity. The complete events in cyclic peptide maturation and export from the bacterial cell remain to be fully defined. We and others recently discovered that the membrane peptidase MroQ is required for pheromone maturation. This study builds off the identification of MroQ and considers the attributes of the pheromone pro-peptide that are required for MroQ-mediated processing as well as uncovers features important for peptide stability and export. Overall, the findings in this study have implications for understanding bacterial pheromone maturation and virulence.
{"title":"Determinants of maturation of the <i>Staphylococcus aureus</i> autoinducing peptide.","authors":"Liwei Fang, Chance Cosgriff, Francis Alonzo","doi":"10.1128/jb.00195-24","DOIUrl":"10.1128/jb.00195-24","url":null,"abstract":"<p><p>The <u>a</u>ccessory <u>g</u>ene <u>r</u>egulatory (Agr) system is required for virulence factor gene expression and pathogenesis of <i>Staphylococcus aureus</i>. The Agr system is activated in response to the accumulation of a cyclic autoinducing peptide (AIP), which is matured and secreted by the bacterium. The precursor of AIP, AgrD, consists of the AIP flanked by an N-terminal [Formula: see text]-helical Leader and a charged C-terminal tail. AgrD is matured to AIP by the action of two proteases, AgrB and MroQ. AgrB cleaves the C-terminal tail and promotes the formation of a thiolactone ring, whereas MroQ cleaves the N-terminal Leader in a manner that depends on the four-amino acid linker immediately following a conserved IG helix breaker motif. However, the attributes of AgrD that dictate the sequence of events in peptide maturation are not fully defined. Here, we used engineered AgrD peptide intermediates to ascertain the sufficiency of MroQ for N-terminal peptide cleavage, peptide export, and generation of mature AIP. We found that MroQ promotes the removal of the N-terminal Leader peptide from both linear and cyclic peptide intermediates, while peptide cyclization remained essential for signaling. The expression of the Leader peptide in isolation was sufficient for MroQ-dependent cleavage proximal to the four-amino-acid linker. In addition, active site mutations within AgrB destabilized full-length AgrD and thiolactone-containing intermediates and prevented the release of the Leader peptide. Altogether, our data support a tandem peptide maturation event involving both MroQ and AgrB that appears to couple protease activity and export of bioactive AIP.IMPORTANCEThe <u>a</u>ccessory <u>g</u>ene <u>r</u>egulatory (Agr) system is important for <i>S. aureus</i> pathogenesis. Activation of the Agr system requires recognition of a cyclic peptide pheromone, which must be fully matured to exert its biological activity. The complete events in cyclic peptide maturation and export from the bacterial cell remain to be fully defined. We and others recently discovered that the membrane peptidase MroQ is required for pheromone maturation. This study builds off the identification of MroQ and considers the attributes of the pheromone pro-peptide that are required for MroQ-mediated processing as well as uncovers features important for peptide stability and export. Overall, the findings in this study have implications for understanding bacterial pheromone maturation and virulence.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11412329/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142035929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-09DOI: 10.1128/jb.00272-24
Matthew R Hauserman, Leia E Sullivan, Kimberly L James, Mariola J Ferraro, Kelly C Rice
Staphylococcus aureus is commonly isolated from astronauts returning from spaceflight. Previous analysis of omics data from S. aureus low Earth orbit cultures indicated significantly increased expression of the Agr quorum sensing system and its downstream targets in spaceflight samples compared to ground controls. In this current study, the rotary cell culture system (RCCS) was used to investigate the effect of low-shear modeled microgravity (LSMMG) on S. aureus physiology and Agr activity. When cultured in the same growth medium and temperature as the previous spaceflight experiment, S. aureus LSMMG cultures exhibited decreased agr expression and altered growth compared to normal gravity control cultures, which are typically oriented with oxygenation membrane on the bottom of the high aspect rotating vessel (HARV). When S. aureus was grown in an inverted gravity control orientation (oxygenation membrane on top of the HARV), reduced Agr activity was observed relative to both traditional control and LSMMG cultures, signifying that oxygen availability may affect the observed differences in Agr activity. Metabolite assays revealed increased lactate and decreased acetate excretion in both LSMMG and inverted control cultures. Secretomics analysis of LSMMG, control, and inverted control HARV culture supernatants corroborated these results, with inverted and LSMMG cultures exhibiting a decreased abundance of Agr-regulated virulence factors and an increased abundance of proteins expressed in low-oxygen conditions. Collectively, these studies suggest that the orientation of the HARV oxygenation membrane can affect S. aureus physiology and Agr quorum sensing in the RCCS, a variable that should be considered when interpreting data using this ground-based microgravity model.IMPORTANCES. aureus is commonly isolated from astronauts returning from spaceflight and from surfaces within human-inhabited closed environments such as spacecraft. Astronaut health and immune function are significantly altered in spaceflight. Therefore, elucidating the effects of microgravity on S. aureus physiology is critical for assessing its pathogenic potential during long-term human space habitation. These results also highlight the necessity of eliminating potential confounding factors when comparing simulated microgravity model data with actual spaceflight experiments.
{"title":"Response of <i>Staphylococcus aureus</i> physiology and Agr quorum sensing to low-shear modeled microgravity.","authors":"Matthew R Hauserman, Leia E Sullivan, Kimberly L James, Mariola J Ferraro, Kelly C Rice","doi":"10.1128/jb.00272-24","DOIUrl":"10.1128/jb.00272-24","url":null,"abstract":"<p><p><i>Staphylococcus aureus</i> is commonly isolated from astronauts returning from spaceflight. Previous analysis of omics data from <i>S. aureus</i> low Earth orbit cultures indicated significantly increased expression of the Agr quorum sensing system and its downstream targets in spaceflight samples compared to ground controls. In this current study, the rotary cell culture system (RCCS) was used to investigate the effect of low-shear modeled microgravity (LSMMG) on <i>S. aureus</i> physiology and Agr activity. When cultured in the same growth medium and temperature as the previous spaceflight experiment, <i>S. aureus</i> LSMMG cultures exhibited decreased <i>agr</i> expression and altered growth compared to normal gravity control cultures, which are typically oriented with oxygenation membrane on the bottom of the high aspect rotating vessel (HARV). When <i>S. aureus</i> was grown in an inverted gravity control orientation (oxygenation membrane on top of the HARV), reduced Agr activity was observed relative to both traditional control and LSMMG cultures, signifying that oxygen availability may affect the observed differences in Agr activity. Metabolite assays revealed increased lactate and decreased acetate excretion in both LSMMG and inverted control cultures. Secretomics analysis of LSMMG, control, and inverted control HARV culture supernatants corroborated these results, with inverted and LSMMG cultures exhibiting a decreased abundance of Agr-regulated virulence factors and an increased abundance of proteins expressed in low-oxygen conditions. Collectively, these studies suggest that the orientation of the HARV oxygenation membrane can affect <i>S. aureus</i> physiology and Agr quorum sensing in the RCCS, a variable that should be considered when interpreting data using this ground-based microgravity model.IMPORTANCE<i>S. aureus</i> is commonly isolated from astronauts returning from spaceflight and from surfaces within human-inhabited closed environments such as spacecraft. Astronaut health and immune function are significantly altered in spaceflight. Therefore, elucidating the effects of microgravity on <i>S. aureus</i> physiology is critical for assessing its pathogenic potential during long-term human space habitation. These results also highlight the necessity of eliminating potential confounding factors when comparing simulated microgravity model data with actual spaceflight experiments.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411946/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141906640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-12DOI: 10.1128/jb.00145-24
Grazia Vizzarro, Alexandre Lemopoulos, David William Adams, Melanie Blokesch
In response to predation by bacteriophages and invasion by other mobile genetic elements such as plasmids, bacteria have evolved specialized defense systems that are often clustered together on genomic islands. The O1 El Tor strains of Vibrio cholerae responsible for the ongoing seventh cholera pandemic (7PET) contain a characteristic set of genomic islands involved in host colonization and disease, many of which contain defense systems. Notably, Vibrio pathogenicity island 2 contains several characterized defense systems as well as a putative type I restriction-modification (T1RM) system, which, interestingly, is interrupted by two genes of unknown function. Here, we demonstrate that the T1RM system is active, methylates the host genomes of a representative set of 7PET strains, and identify a specific recognition sequence that targets non-methylated plasmids for restriction. We go on to show that the two genes embedded within the T1RM system encode a novel two-protein modification-dependent restriction system related to the GmrSD family of type IV restriction enzymes. Indeed, we show that this system has potent anti-phage activity against diverse members of the Tevenvirinae, a subfamily of bacteriophages with hypermodified genomes. Taken together, these results expand our understanding of how this highly conserved genomic island contributes to the defense of pandemic V. cholerae against foreign DNA.
Importance: Defense systems are immunity systems that allow bacteria to counter the threat posed by bacteriophages and other mobile genetic elements. Although these systems are numerous and highly diverse, the most common types are restriction enzymes that can specifically recognize and degrade non-self DNA. Here, we show that the Vibrio pathogenicity island 2, present in the pathogen Vibrio cholerae, encodes two types of restriction systems that use distinct mechanisms to sense non-self DNA. The first system is a classical Type I restriction-modification system, and the second is a novel modification-dependent type IV restriction system that recognizes hypermodified cytosines. Interestingly, these systems are embedded within each other, suggesting that they are complementary to each other by targeting both modified and non-modified phages.
为了应对噬菌体的捕食和质粒等其他移动遗传因子的入侵,细菌进化出了专门的防御系统,这些系统通常聚集在基因组岛上。造成目前第七次霍乱大流行(7PET)的霍乱弧菌 O1 El Tor 菌株含有一组参与宿主定殖和疾病的特征性基因组岛,其中许多含有防御系统。值得注意的是,致病性弧菌岛 2 包含多个特征性防御系统以及一个假定的 I 型限制性修饰(T1RM)系统,有趣的是,该系统被两个功能未知的基因打断。在这里,我们证明了 T1RM 系统是活跃的,它能使一组具有代表性的 7PET 菌株的宿主基因组甲基化,并确定了一个特定的识别序列,该序列能对非甲基化质粒进行限制。我们进而证明,T1RM 系统中的两个基因编码一种新型的双蛋白修饰依赖性限制系统,与 GmrSD 家族的 IV 型限制酶有关。事实上,我们发现该系统对特文病毒科(Tevenvirinae)的不同成员具有很强的抗噬菌体活性,特文病毒科是一个具有超修饰基因组的噬菌体亚家族。总之,这些结果拓展了我们对这一高度保守的基因组岛如何帮助大流行性霍乱弧菌抵御外来 DNA 的理解:防御系统是一种免疫系统,可使细菌抵御噬菌体和其他移动遗传因子的威胁。虽然这些系统种类繁多且高度多样化,但最常见的类型是限制酶,它能特异性地识别和降解非自身 DNA。在这里,我们发现病原体霍乱弧菌中的致病性弧菌岛 2 编码两种类型的限制性系统,它们使用不同的机制来感知非自身 DNA。第一种系统是经典的 I 型限制-修饰系统,第二种是新型的依赖修饰的 IV 型限制系统,它能识别超修饰的胞嘧啶。有趣的是,这些系统彼此内嵌,表明它们通过靶向修饰和非修饰噬菌体而相互补充。
{"title":"<i>Vibrio cholerae</i> pathogenicity island 2 encodes two distinct types of restriction systems.","authors":"Grazia Vizzarro, Alexandre Lemopoulos, David William Adams, Melanie Blokesch","doi":"10.1128/jb.00145-24","DOIUrl":"10.1128/jb.00145-24","url":null,"abstract":"<p><p>In response to predation by bacteriophages and invasion by other mobile genetic elements such as plasmids, bacteria have evolved specialized defense systems that are often clustered together on genomic islands. The O1 El Tor strains of <i>Vibrio cholerae</i> responsible for the ongoing seventh cholera pandemic (7PET) contain a characteristic set of genomic islands involved in host colonization and disease, many of which contain defense systems. Notably, <i>Vibrio</i> pathogenicity island 2 contains several characterized defense systems as well as a putative type I restriction-modification (T1RM) system, which, interestingly, is interrupted by two genes of unknown function. Here, we demonstrate that the T1RM system is active, methylates the host genomes of a representative set of 7PET strains, and identify a specific recognition sequence that targets non-methylated plasmids for restriction. We go on to show that the two genes embedded within the T1RM system encode a novel two-protein modification-dependent restriction system related to the GmrSD family of type IV restriction enzymes. Indeed, we show that this system has potent anti-phage activity against diverse members of the <i>Tevenvirinae</i>, a subfamily of bacteriophages with hypermodified genomes. Taken together, these results expand our understanding of how this highly conserved genomic island contributes to the defense of pandemic <i>V. cholerae</i> against foreign DNA.</p><p><strong>Importance: </strong>Defense systems are immunity systems that allow bacteria to counter the threat posed by bacteriophages and other mobile genetic elements. Although these systems are numerous and highly diverse, the most common types are restriction enzymes that can specifically recognize and degrade non-self DNA. Here, we show that the <i>Vibrio</i> pathogenicity island 2, present in the pathogen <i>Vibrio cholerae</i>, encodes two types of restriction systems that use distinct mechanisms to sense non-self DNA. The first system is a classical Type I restriction-modification system, and the second is a novel modification-dependent type IV restriction system that recognizes hypermodified cytosines. Interestingly, these systems are embedded within each other, suggesting that they are complementary to each other by targeting both modified and non-modified phages.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411939/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141916733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Members of the kingdom Nanobdellati, previously known as DPANN archaea, are characterized by ultrasmall cell sizes and reduced genomes. They primarily thrive through ectosymbiotic interactions with specific hosts in diverse environments. Recent successful cultivations have emphasized the importance of adhesion to host cells for understanding the ecophysiology of Nanobdellati. Cell adhesion is often mediated by cell surface carbohydrates, and in archaea, this may be facilitated by the glycosylated S-layer protein that typically coats their cell surface. In this study, we conducted glycoproteomic analyses on two co-cultures of Nanobdellati with their host archaea, as well as on pure cultures of both host and non-host archaea. Nanobdellati exhibited various glycoproteins, including archaellins and hypothetical proteins, with glycans that were structurally distinct from those of their hosts. This indicated that Nanobdellati autonomously synthesize their glycans for protein modifications probably using host-derived substrates, despite the high energy cost. Glycan modifications on Nanobdellati proteins consistently occurred on asparagine residues within the N-X-S/T sequon, consistent with patterns observed across archaea, bacteria, and eukaryotes. In both host and non-host archaea, S-layer proteins were commonly modified with hexose, N-acetylhexosamine, and sulfonated deoxyhexose. However, the N-glycan structures of host archaea, characterized by distinct sugars such as deoxyhexose, nonulosonate sugar, and pentose at the nonreducing ends, were implicated in enabling Nanobdellati to differentiate between host and non-host cells. Interestingly, the specific sugar, xylose, was eliminated from the N-glycan in a host archaeon when co-cultured with Nanobdella. These findings enhance our understanding of the role of protein glycosylation in archaeal interactions.IMPORTANCENanobdellati archaea, formerly known as DPANN, are phylogenetically diverse, widely distributed, and obligately ectosymbiotic. The molecular mechanisms by which Nanobdellati recognize and adhere to their specific hosts remain largely unexplored. Protein glycosylation, a fundamental biological mechanism observed across all domains of life, is often crucial for various cell-cell interactions. This study provides the first insights into the glycoproteome of Nanobdellati and their host and non-host archaea. We discovered that Nanobdellati autonomously synthesize glycans for protein modifications, probably utilizing substrates derived from their hosts. Additionally, we identified distinctive glycosylation patterns that suggest mechanisms through which Nanobdellati differentiate between host and non-host cells. This research significantly advances our understanding of the molecular basis of microbial interactions in extreme environments.
{"title":"<i>N</i>-linked protein glycosylation in <i>Nanobdellati</i> (formerly DPANN) archaea and their hosts.","authors":"Satoshi Nakagawa, Hiroyuki D Sakai, Shigeru Shimamura, Yoshiki Takamatsu, Shingo Kato, Hirokazu Yagi, Saeko Yanaka, Maho Yagi-Utsumi, Norio Kurosawa, Moriya Ohkuma, Koichi Kato, Ken Takai","doi":"10.1128/jb.00205-24","DOIUrl":"10.1128/jb.00205-24","url":null,"abstract":"<p><p>Members of the kingdom <i>Nanobdellati</i>, previously known as DPANN archaea, are characterized by ultrasmall cell sizes and reduced genomes. They primarily thrive through ectosymbiotic interactions with specific hosts in diverse environments. Recent successful cultivations have emphasized the importance of adhesion to host cells for understanding the ecophysiology of <i>Nanobdellati</i>. Cell adhesion is often mediated by cell surface carbohydrates, and in archaea, this may be facilitated by the glycosylated S-layer protein that typically coats their cell surface. In this study, we conducted glycoproteomic analyses on two co-cultures of <i>Nanobdellati</i> with their host archaea, as well as on pure cultures of both host and non-host archaea. <i>Nanobdellati</i> exhibited various glycoproteins, including archaellins and hypothetical proteins, with glycans that were structurally distinct from those of their hosts. This indicated that <i>Nanobdellati</i> autonomously synthesize their glycans for protein modifications probably using host-derived substrates, despite the high energy cost. Glycan modifications on <i>Nanobdellati</i> proteins consistently occurred on asparagine residues within the N-X-S/T sequon, consistent with patterns observed across archaea, bacteria, and eukaryotes. In both host and non-host archaea, S-layer proteins were commonly modified with hexose, <i>N</i>-acetylhexosamine, and sulfonated deoxyhexose. However, the <i>N</i>-glycan structures of host archaea, characterized by distinct sugars such as deoxyhexose, nonulosonate sugar, and pentose at the nonreducing ends, were implicated in enabling <i>Nanobdellati</i> to differentiate between host and non-host cells. Interestingly, the specific sugar, xylose, was eliminated from the <i>N</i>-glycan in a host archaeon when co-cultured with <i>Nanobdella</i>. These findings enhance our understanding of the role of protein glycosylation in archaeal interactions.IMPORTANCE<i>Nanobdellati</i> archaea, formerly known as DPANN, are phylogenetically diverse, widely distributed, and obligately ectosymbiotic. The molecular mechanisms by which <i>Nanobdellati</i> recognize and adhere to their specific hosts remain largely unexplored. Protein glycosylation, a fundamental biological mechanism observed across all domains of life, is often crucial for various cell-cell interactions. This study provides the first insights into the glycoproteome of <i>Nanobdellati</i> and their host and non-host archaea. We discovered that <i>Nanobdellati</i> autonomously synthesize glycans for protein modifications, probably utilizing substrates derived from their hosts. Additionally, we identified distinctive glycosylation patterns that suggest mechanisms through which <i>Nanobdellati</i> differentiate between host and non-host cells. This research significantly advances our understanding of the molecular basis of microbial interactions in extreme environments.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411935/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142080391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19Epub Date: 2024-08-13DOI: 10.1128/jb.00271-24
Rebecca J Prest, Konstantin V Korotkov, Patricia A Champion
Pathogenic mycobacteria are a significant global health burden. The ESX-1 secretion system is essential for mycobacterial pathogenesis. The secretion of ESX-1 substrates is required for phagosomal lysis, which allows the bacteria to enter the macrophage cytoplasm, induce a Type I IFN response, and spread to new host cells. EspE and EspF are dual-functioning ESX-1 substrates. Inside the mycobacterial cell, they regulate transcription of ESX-1-associated genes. Following secretion, EspE and EspF are essential for lytic activity. The link between EspE/F secretion and regulatory function has not been investigated. We investigated the relationship between EspE and EspF using molecular genetics in Mycobacterium marinum, a non-tuberculous mycobacterial species that serves as an established model for ESX-1 secretion and function in Mycobacterium tuberculosis. Our data support that EspE and EspF, which require each other for secretion, directly interact. The disruption of the predicted protein-protein interaction abrogates hemolytic activity and secretion but does not impact their gene regulatory activities in the mycobacterial cell. In addition, we predict a direct protein-protein interaction between the EsxA/EsxB heterodimer and EspF. Our data support that the EspF/EsxA interaction is also required for hemolytic activity and EspE secretion. Our study sheds light on the intricate molecular mechanisms governing the interactions between ESX-1 substrates, regulatory function, and ESX-1 secretion, moving the field forward.IMPORTANCETuberculosis (TB), caused by Mycobacterium tuberculosis, is a historical and pervasive disease responsible for millions of deaths annually. The rise of antibiotic and treatment-resistant TB, as well as the rise of infection by non-tuberculous mycobacterial species, calls for a better understanding of pathogenic mycobacteria. The ESX-1 secreted substrates, EspE and EspF, are required for mycobacterial virulence and may be responsible for phagosomal lysis. This study focuses on the mechanism of EspE and EspF secretion from the mycobacterial cell.
{"title":"The regulatory functions of ESX-1 substrates, EspE and EspF, are separable from secretion.","authors":"Rebecca J Prest, Konstantin V Korotkov, Patricia A Champion","doi":"10.1128/jb.00271-24","DOIUrl":"10.1128/jb.00271-24","url":null,"abstract":"<p><p>Pathogenic mycobacteria are a significant global health burden. The ESX-1 secretion system is essential for mycobacterial pathogenesis. The secretion of ESX-1 substrates is required for phagosomal lysis, which allows the bacteria to enter the macrophage cytoplasm, induce a Type I IFN response, and spread to new host cells. EspE and EspF are dual-functioning ESX-1 substrates. Inside the mycobacterial cell, they regulate transcription of ESX-1-associated genes. Following secretion, EspE and EspF are essential for lytic activity. The link between EspE/F secretion and regulatory function has not been investigated. We investigated the relationship between EspE and EspF using molecular genetics in <i>Mycobacterium marinum</i>, a non-tuberculous mycobacterial species that serves as an established model for ESX-1 secretion and function in <i>Mycobacterium tuberculosis</i>. Our data support that EspE and EspF, which require each other for secretion, directly interact. The disruption of the predicted protein-protein interaction abrogates hemolytic activity and secretion but does not impact their gene regulatory activities in the mycobacterial cell. In addition, we predict a direct protein-protein interaction between the EsxA/EsxB heterodimer and EspF. Our data support that the EspF/EsxA interaction is also required for hemolytic activity and EspE secretion. Our study sheds light on the intricate molecular mechanisms governing the interactions between ESX-1 substrates, regulatory function, and ESX-1 secretion, moving the field forward.IMPORTANCETuberculosis (TB), caused by <i>Mycobacterium tuberculosis</i>, is a historical and pervasive disease responsible for millions of deaths annually. The rise of antibiotic and treatment-resistant TB, as well as the rise of infection by non-tuberculous mycobacterial species, calls for a better understanding of pathogenic mycobacteria. The ESX-1 secreted substrates, EspE and EspF, are required for mycobacterial virulence and may be responsible for phagosomal lysis. This study focuses on the mechanism of EspE and EspF secretion from the mycobacterial cell.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411940/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141971188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}