scholarly journals Refining the Pneumococcal Competence Regulon by RNA Sequencing

2019 ◽  
Vol 201 (13) ◽  
Author(s):  
Jelle Slager ◽  
Rieza Aprianto ◽  
Jan-Willem Veening
Keyword(s):  
Antibiotic Resistance ◽  
Streptococcus Pneumoniae ◽  
Rna Sequencing ◽  
Genome Annotation ◽  
Stress Factors ◽  
Microarray Technology ◽  
Human Pathogen ◽  
Exogenous Dna ◽  
Content Type ◽  
Opportunistic Human Pathogen

ABSTRACTCompetence for genetic transformation allows the opportunistic human pathogenStreptococcus pneumoniaeto take up exogenous DNA for incorporation into its own genome. This ability may account for the extraordinary genomic plasticity of this bacterium, leading to antigenic variation, vaccine escape, and the spread of antibiotic resistance. The competence system has been thoroughly studied, and its regulation is well understood. Additionally, over the last decade, several stress factors have been shown to trigger the competent state, leading to the activation of several stress response regulons. The arrival of next-generation sequencing techniques allowed us to update the competence regulon, the latest report on which still depended on DNA microarray technology. Enabled by the availability of an up-to-date genome annotation, including transcript boundaries, we assayed time-dependent expression of all annotated features in response to competence induction, were able to identify the affected promoters, and produced a more complete overview of the various regulons activated during the competence state. We show that 4% of all annotated genes are under direct control of competence regulators ComE and ComX, while the expression of a total of up to 17% of all genes is affected, either directly or indirectly. Among the affected genes are various small RNAs with an as-yet-unknown function. Besides the ComE and ComX regulons, we were also able to refine the CiaR, VraR (LiaR), and BlpR regulons, underlining the strength of combining transcriptome sequencing (RNA-seq) with a well-annotated genome.IMPORTANCEStreptococcus pneumoniaeis an opportunistic human pathogen responsible for over a million deaths every year. Although both vaccination programs and antibiotic therapies have been effective in prevention and treatment of pneumococcal infections, respectively, the sustainability of these solutions is uncertain. The pneumococcal genome is highly flexible, leading to vaccine escape and antibiotic resistance. This flexibility is predominantly facilitated by competence, a state allowing the cell to take up and integrate exogenous DNA. Thus, it is essential to obtain a detailed overview of gene expression during competence. This is stressed by the fact that administration of several classes of antibiotics can lead to competence. Previous studies on the competence regulon were performed with microarray technology and were limited to an incomplete set of known genes. Using RNA sequencing combined with an up-to-date genome annotation, we provide an updated overview of competence-regulated genes.

scholarly journals The ParB-parS Chromosome Segregation System Modulates Competence Development in Streptococcus pneumoniae

mBio ◽  
2015 ◽  
Vol 6 (4) ◽  
Author(s):  
Laetitia Attaiech ◽  
Anita Minnen ◽  
Morten Kjos ◽  
Stephan Gruber ◽  
Jan-Willem Veening
Keyword(s):  
Streptococcus Pneumoniae ◽  
Chromosome Segregation ◽  
Dna Sequences ◽  
Molecular Mechanisms ◽  
Developmental Process ◽  
Competence Development ◽  
Human Pathogen ◽  
Transcription Analysis ◽  
Exogenous Dna ◽  
Content Type

ABSTRACT ParB proteins bind centromere-like DNA sequences called parS sites and are involved in plasmid and chromosome segregation in bacteria. We previously showed that the opportunistic human pathogen Streptococcus pneumoniae contains four parS sequences located close to the origin of replication which are bound by ParB. Using chromatin immunoprecipitation (ChIP), we found here that ParB spreads out from one of these parS sites, parS(−1.6°), for more than 5 kb and occupies the nearby comCDE operon, which drives competence development. Competence allows S. pneumoniae to take up DNA from its environment, thereby mediating horizontal gene transfer, and is also employed as a general stress response. Mutating parS(−1.6°) or deleting parB resulted in transcriptional up-regulation of comCDE and ssbB (a gene belonging to the competence regulon), demonstrating that ParB acts as a repressor of competence. However, genome-wide transcription analysis showed that ParB is not a global transcriptional regulator. Different factors, such as the composition of the growth medium and antibiotic-induced stress, can trigger the sensitive switch driving competence. This work shows that the ParB-parS chromosome segregation machinery also influences this developmental process. IMPORTANCE Streptococcus pneumoniae (pneumococcus) is an important human pathogen responsible for more than a million deaths each year. Like all other organisms, S. pneumoniae must be able to segregate its chromosomes properly. Not only is understanding the molecular mechanisms underlying chromosome segregation in S. pneumoniae therefore of fundamental importance, but also, this knowledge might offer new leads for ways to target this pathogen. Here, we identified a link between the pneumococcal chromosome segregation system and the competence-developmental system. Competence allows S. pneumoniae to take up and integrate exogenous DNA in its chromosome. This process plays a crucial role in successful adaptation to—and escape from—host defenses, antibiotic treatments, and vaccination strategies. We show that the chromosome segregation protein ParB acts as a repressor of competence. To the best of our knowledge, this is the first example of a ParB protein controlling bacterial competence.

scholarly journals JMM Profile: Streptococcus pneumoniae: sugar-coated captain of the men of death

2021 ◽  
Vol 70 (11) ◽  
Author(s):  
Tina H. Dao ◽  
Jason W. Rosch
Keyword(s):  
Antibiotic Resistance ◽  
Streptococcus Pneumoniae ◽  
Virulence Factors ◽  
Immune Evasion ◽  
Type Species ◽  
Genetic Material ◽  
Human Pathogen ◽  
Content Type ◽  
Invasive Diseases ◽  
Respiratory Microbiota

Streptococcus pneumoniae is a highly adept human pathogen. A frequent asymptomatic member of the respiratory microbiota, the pneumococcus has a remarkable capacity to cause mucosal (pneumonia and otitis media) and invasive diseases (bacteremia, meningitis). In addition, the organism utilizes a vast battery of virulence factors for tissue and immune evasion. Though recognized as a significant cause of pneumonia for over a century, efforts to develop more effective vaccines remain ongoing. The pathogen’s inherent capacity to exchange genetic material is critical to the pneumococcus’ success. This feature historically facilitated essential discoveries in genetics and is vital for disseminating antibiotic resistance and vaccine evasion.

scholarly journals Complete Genome Sequence of Stenotrophomonas Phage Mendera

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Kameron D. Garza ◽  
Heather Newkirk ◽  
Russell Moreland ◽  
Carlos F. Gonzalez ◽  
Mei Liu ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Stenotrophomonas Maltophilia ◽  
Human Pathogen ◽  
Base Pairs ◽  
Content Type ◽  
Genomic Annotation ◽  
Opportunistic Human Pathogen

Stenotrophomonas maltophilia is an emerging opportunistic human pathogen. In this report, we describe the isolation and genomic annotation of the S. maltophilia-infecting bacteriophage Mendera. A myophage of 159,961 base pairs, Mendera is T4-like and related most closely to Stenotrophomonas phage IME-SM1.

scholarly journals Serum Albumin and Ca2+Are Natural Competence Inducers in the Human Pathogen Acinetobacter baumannii

2016 ◽  
Vol 60 (8) ◽  
pp. 4920-4929 ◽  
Author(s):  
German Matias Traglia ◽  
Brettni Quinn ◽  
Sareda T. J. Schramm ◽  
Alfonso Soler-Bistue ◽  
Maria Soledad Ramirez
Keyword(s):  
Acinetobacter Baumannii ◽  
Natural Transformation ◽  
Hospital Environment ◽  
Human Pathogen ◽  
Nosocomial Pathogen ◽  
Natural Competence ◽  
Exogenous Dna ◽  
Content Type ◽  
Resistance Determinants ◽  
Main Protein

ABSTRACTThe increasing frequency of bacteria showing antimicrobial resistance (AMR) raises the menace of entering into a postantibiotic era. Horizontal gene transfer (HGT) is one of the prime reasons for AMR acquisition.Acinetobacter baumanniiis a nosocomial pathogen with outstanding abilities to survive in the hospital environment and to acquire resistance determinants. Its capacity to incorporate exogenous DNA is a major source of AMR genes; however, few studies have addressed this subject. The transformation machinery as well as the factors that induce natural competence inA. baumanniiare unknown. In this study, we demonstrate that naturally competent strain A118 increases its natural transformation frequency upon the addition of Ca2+or albumin. We show thatcomEAandpilQare involved in this process since their expression levels are increased upon the addition of these compounds. An unspecific protein, like casein, does not reproduce this effect, showing that albumin's effect is specific. Our work describes the first specific inducers of natural competence inA. baumannii. Overall, our results suggest that the main protein in blood enhances HGT inA. baumannii, contributing to the increase of AMR in this threatening human pathogen.

scholarly journals Bacteriophages LIMElight and LIMEzero of Pantoea agglomerans, Belonging to the “phiKMV-Like Viruses”

2011 ◽  
Vol 77 (10) ◽  
pp. 3443-3450 ◽  
Author(s):  
Evelien M. Adriaenssens ◽  
Pieter-Jan Ceyssens ◽  
Vincent Dunon ◽  
Hans-Wolfgang Ackermann ◽  
Johan Van Vaerenbergh ◽  
...  
Keyword(s):  
Soil Samples ◽  
Pantoea Agglomerans ◽  
Open Reading Frames ◽  
Human Pathogen ◽  
Content Type ◽  
Host Diversity ◽  
Double Stranded Dna ◽  
Opportunistic Human Pathogen ◽  
Reading Frames

ABSTRACTPantoea agglomeransis a common soil bacterium used in the biocontrol of fungi and bacteria but is also an opportunistic human pathogen. It has been described extensively in this context, but knowledge of bacteriophages infecting this species is limited. Bacteriophages LIMEzero and LIMElight ofP. agglomeransare lytic phages, isolated from soil samples, belonging to thePodoviridaeand are the firstPantoeaphages of this family to be described. The double-stranded DNA (dsDNA) genomes (43,032 bp and 44,546 bp, respectively) encode 57 and 55 open reading frames (ORFs). Based on the presence of an RNA polymerase in their genomes and their overall genome architecture, these phages should be classified in the subfamily of theAutographivirinae, within the genus of the “phiKMV-like viruses.” Phylogenetic analysis of all the sequenced members of theAutographivirinaesupports the classification of phages LIMElight and LIMEzero as members of the “phiKMV-like viruses” and corroborates the subdivision into the different genera. These data expand the knowledge ofPantoeaphages and illustrate the wide host diversity of phages within the “phiKMV-like viruses.”

scholarly journals Global transcriptome analysis of Stenotrophomonas maltophilia in response to growth at human body temperature

2021 ◽  
Vol 7 (7) ◽  
Author(s):  
Prashant P. Patil ◽  
Sanjeet Kumar ◽  
Amandeep Kaur ◽  
Samriti Midha ◽  
Kanika Bansal ◽  
...  
Keyword(s):  
Body Temperature ◽  
Human Body ◽  
Transcriptome Analysis ◽  
Stenotrophomonas Maltophilia ◽  
Type Species ◽  
Human Pathogen ◽  
Content Type ◽  
Link Type ◽  
Human Body Temperature ◽  
Opportunistic Human Pathogen

Stenotrophomonas maltophilia is a typical example of an environmental originated opportunistic human pathogen, which can thrive at different habitats including the human body and can cause a wide range of infections. It must cope with heat stress during transition from the environment to the human body as the physiological temperature of the human body (37 °C) is higher than environmental niches (22–30 °C). Interestingly, S. rhizophila a phylogenetic neighbour of S. maltophilia within genus Stenotrophomonas is unable to grow at 37 °C. Thus, it is crucial to understand how S. maltophilia is adapted to human body temperature, which could suggest its evolution as an opportunistic human pathogen. In this study, we have performed comparative transcriptome analysis of S. maltophilia grown at 28 and 37 °C as temperature representative for environmental niches and the human body, respectively. RNA-Seq analysis revealed several interesting findings showing alterations in gene-expression levels at 28 and 37 °C, which can play an important role during infection. We have observed downregulation of genes involved in cellular motility, energy production and metabolism, replication and repair whereas upregulation of VirB/D4 type IV secretion system, aerotaxis, cation diffusion facilitator family transporter and LacI family transcriptional regulators at 37 °C. Microscopy and plate assays corroborated altered expression of genes involved in motility. The results obtained enhance our understanding of the strategies employed by S. maltophilia during adaptation towards the human body.

scholarly journals Studies on Bd0934 and Bd3507, Two Secreted Nucleases from Bdellovibrio bacteriovorus, Reveal Sequential Release of Nucleases during the Predatory Cycle

2020 ◽  
Vol 202 (18) ◽  
Author(s):  
Ewa Bukowska-Faniband ◽  
Tilde Andersson ◽  
Rolf Lood
Keyword(s):  
Antibiotic Resistance ◽  
Life Cycle ◽  
Antibiotic Resistance Genes ◽  
Human Pathogens ◽  
Temporal Expression ◽  
Bdellovibrio Bacteriovorus ◽  
Exogenous Dna ◽  
Content Type ◽  
Genes Encoding ◽  
Predatory Bacteria

ABSTRACT Bdellovibrio bacteriovorus is an obligate predatory bacterium that invades and kills a broad range of Gram-negative prey cells, including human pathogens. Its potential therapeutic application has been the subject of increased research interest in recent years. However, an improved understanding of the fundamental molecular aspects of the predatory life cycle is crucial for developing this bacterium as a “living antibiotic.” During intracellular growth, B. bacteriovorus secretes an arsenal of hydrolases, which digest the content of the host cell to provide growth nutrients for the predator, e.g., prey DNA is completely degraded by the nucleases. Here, we have, on a genetic and molecular level, characterized two secreted DNases from B. bacteriovorus, Bd0934 and Bd3507, and determined the temporal expression profile of other putative secreted nucleases. We conclude that Bd0934 and Bd3507 are likely a part of the predatosome but are not essential for the predation, host-independent growth, prey biofilm degradation, and self-biofilm formation. The detailed temporal expression analysis of genes encoding secreted nucleases revealed that these enzymes are produced in a sequential orchestrated manner. This work contributes to our understanding of the sequential breakdown of the prey nucleic acid by the nucleases secreted during the predatory life cycle of B. bacteriovorus. IMPORTANCE Antibiotic resistance is a major global concern with few available new means to combat it. From a therapeutic perspective, predatory bacteria constitute an interesting tool. They not only eliminate the pathogen but also reduce the overall pool of antibiotic resistance genes through secretion of nucleases and complete degradation of exogenous DNA. Molecular knowledge of how these secreted DNases act will give us further insight into how antibiotic resistance, and the spread thereof, can be limited through the action of predatory bacteria.

scholarly journals Complex Control of a Genomic Island Governing Biofilm and Rugose Colony Development in Vibrio vulnificus

2018 ◽  
Vol 200 (16) ◽  
Author(s):  
Daniel M. Chodur ◽  
Dean A. Rowe-Magnus
Keyword(s):  
Food Chain ◽  
Horizontal Transfer ◽  
Vibrio Vulnificus ◽  
Regulatory Control ◽  
Colony Development ◽  
Dependent Manner ◽  
Human Pathogen ◽  
Content Type ◽  
Regulatory Pathways ◽  
Opportunistic Human Pathogen

ABSTRACT Vibrio vulnificus is a potent opportunistic human pathogen that contaminates the human food chain by asymptomatically colonizing seafood. The expression of the 9-gene brp exopolysaccharide locus mediates surface adherence and is controlled by the secondary signaling molecule c-di-GMP and the regulator BrpT. Here, we show that c-di-GMP and BrpT also regulate the expression of an adjacent 5-gene cluster that includes the cabABC operon, brpT, and another VpsT-like transcriptional regulator gene, brpS. The expression of the 14 genes spanning the region increased with elevated intracellular c-di-GMP levels in a BrpT-dependent manner, save for brpS, which was positively regulated by c-di-GMP and repressed by BrpT. BrpS repressed brpA expression and was required for rugose colony development. The mutation of its consensus WFSA c-di-GMP binding motif blocked these activities, suggesting that BrpS function is dependent on binding c-di-GMP. BrpT specifically bound the cabA, brpT, and brpS promoters, and binding sites homologous to the Vibrio cholerae VpsT binding site were identified upstream of brpA and brpT. Transcription was initiated distal to brpA, and a conserved RfaH-recruiting ops element and a potential Rho utilization (rut) terminator site were identified within the 100-bp leader region, suggesting the integration of early termination and operon polarity suppression into the regulation of brp transcription. The GC content and codon usage of the 16-kb brp region was 5.5% lower relative to that of the flanking DNA, suggesting its recent assimilation via horizontal transfer. Thus, architecturally, the brp region can be considered an acquired biofilm and rugosity island that is subject to complex regulation. IMPORTANCE Biofilm and rugose colony formation are developmental programs that underpin the evolution of Vibrio vulnificus as a potent opportunistic human pathogen and successful environmental organism. A better understanding of the regulatory pathways governing theses phenotypes promotes the development and implementation of strategies to mitigate food chain contamination by this pathogen. c-di-GMP signaling is central to both pathways. We show that the molecule orchestrates the expression of 14 genes clustered in a 16-kb segment of the genome that governs biofilm and rugose colony development. This region exhibits the hallmarks of horizontal transfer, suggesting complex regulatory control of a recently assimilated genetic island governing the colonization response of V. vulnificus.

scholarly journals Contextual Flexibility in Pseudomonas aeruginosa Central Carbon Metabolism during Growth in Single Carbon Sources

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Stephen K. Dolan ◽  
Michael Kohlstedt ◽  
Stephen Trigg ◽  
Pedro Vallejo Ramirez ◽  
Clemens F. Kaminski ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Metabolic Flux ◽  
Antimicrobial Agents ◽  
Carbon Sources ◽  
Aerobic Denitrification ◽  
Human Pathogen ◽  
Content Type ◽  
Opportunistic Human Pathogen

ABSTRACT Pseudomonas aeruginosa is an opportunistic human pathogen, particularly noted for causing infections in the lungs of people with cystic fibrosis (CF). Previous studies have shown that the gene expression profile of P. aeruginosa appears to converge toward a common metabolic program as the organism adapts to the CF airway environment. However, we still have only a limited understanding of how these transcriptional changes impact metabolic flux at the systems level. To address this, we analyzed the transcriptome, proteome, and fluxome of P. aeruginosa grown on glycerol or acetate. These carbon sources were chosen because they are the primary breakdown products of an airway surfactant, phosphatidylcholine, which is known to be a major carbon source for P. aeruginosa in CF airways. We show that the fluxes of carbon throughout central metabolism are radically different among carbon sources. For example, the newly recognized “EDEMP cycle” (which incorporates elements of the Entner-Doudoroff [ED] pathway, the Embden-Meyerhof-Parnas [EMP] pathway, and the pentose phosphate [PP] pathway) plays an important role in supplying NADPH during growth on glycerol. In contrast, the EDEMP cycle is attenuated during growth on acetate, and instead, NADPH is primarily supplied by the reaction catalyzed by isocitrate dehydrogenase(s). Perhaps more importantly, our proteomic and transcriptomic analyses revealed a global remodeling of gene expression during growth on the different carbon sources, with unanticipated impacts on aerobic denitrification, electron transport chain architecture, and the redox economy of the cell. Collectively, these data highlight the remarkable metabolic plasticity of P. aeruginosa; that plasticity allows the organism to seamlessly segue between different carbon sources, maximizing the energetic yield from each. IMPORTANCE Pseudomonas aeruginosa is an opportunistic human pathogen that is well known for causing infections in the airways of people with cystic fibrosis. Although it is clear that P. aeruginosa is metabolically well adapted to life in the CF lung, little is currently known about how the organism metabolizes the nutrients available in the airways. In this work, we used a combination of gene expression and isotope tracer (“fluxomic”) analyses to find out exactly where the input carbon goes during growth on two CF-relevant carbon sources, acetate and glycerol (derived from the breakdown of lung surfactant). We found that carbon is routed (“fluxed”) through very different pathways during growth on these substrates and that this is accompanied by an unexpected remodeling of the cell’s electron transfer pathways. Having access to this “blueprint” is important because the metabolism of P. aeruginosa is increasingly being recognized as a target for the development of much-needed antimicrobial agents.

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