scholarly journals Fine-tuning cellular levels of DprA ensures transformant fitness in the human pathogenStreptococcus pneumoniae

2018 ◽  
Author(s):  
Calum Johnston ◽  
Isabelle Mortier-Barriere ◽  
Vanessa Khemici ◽  
Patrice Polard
Keyword(s):  
Streptococcus Pneumoniae ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Physiological State ◽  
Fine Tuning ◽  
Primary Role ◽  
Human Pathogen ◽  
Adaptive Potential ◽  
Genetic Traits ◽  
Full Expression

AbstractNatural genetic transformation is a widespread mechanism of bacterial horizontal gene transfer. Transformation involves the internalization of exogenous DNA as single strands, followed by chromosomal integration via homologous recombination, promoting acquisition of new genetic traits. Transformation occurs during a distinct physiological state called competence, during which all proteins required to transform are produced. In the human pathogenStreptococcus pneumoniae, competence is controlled by a two-component system ComDE, which is induced by an exported peptide pheromone. DprA is universal among transformable species, strongly and specifically induced during pneumococcal competence, and crucial for pneumococcal transformation. Pneumococcal DprA plays three crucial roles in transformation and competence. Firstly, DprA protects internalized single-stranded (ss) DNA from degradation. Secondly, DprA loads the homologous recombinase RecA onto transforming ssDNA to promote transformation. Finally, DprA interacts with the response regulator ComE to shut-off pneumococcal competence. Pneumococcal shut-off has been linked to physiology, with long growth delays in competentdprA-cells. Here, we explored the effect of altering the cellular levels of DprA on these three roles. High cellular levels of DprA were not required for the primary role of DprA as a transformation-dedicated recombinase loader or for protection of transforming ssDNA. In contrast, full expression ofdprAwas required for optimal competence shut-off. Full expression ofdprAwas also crucial for transformant fitness. High cellular levels of DprA in competent cells thus ensure the fitness of pneumococcal transformants by promoting competence shut-off. This promotes survival and propagation of transformants, thus maximizing the adaptive potential of this human pathogen.ImportanceTransformation is a widespread mechanism of horizontal gene transfer that allows bacteria to acquire new genetic traits by internalizing foreign DNA and integrating it into their chromosomes. Transformation occurs during a transient physiological state called competence. DprA is conserved in transformable species and crucial for the protection and integration of transforming DNA. In the human pathogenStreptococcus pneumoniae, DprA is highly abundant and is also crucial for competence shut-off. Here, we show that high DprA expression is not required for transformation. In contrast, full expression ofdprAwas required for competence shut-off and transformant fitness. These findings thus link high cellular levels of DprA to survival and propagation of pneumococcal transformants, maximizing the adaptive potential of this human pathogen.

scholarly journals Complete Genome Sequence of Neisseria gonorrhoeae NCCP11945

2008 ◽  
Vol 190 (17) ◽  
pp. 6035-6036 ◽  
Author(s):  
Gyung Tae Chung ◽  
Jeong Sik Yoo ◽  
Hee Bok Oh ◽  
Yeong Seon Lee ◽  
Sun Ho Cha ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Neisseria Gonorrhoeae ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Multidrug Resistant ◽  
Human Pathogen ◽  
Korean Patient

ABSTRACT Neisseria gonorrhoeae is an obligate human pathogen that is the etiological agent of gonorrhea. We explored variations in the genes of a multidrug-resistant N. gonorrhoeae isolate from a Korean patient in an effort to understand the prevalence, antibiotic resistance, and importance of horizontal gene transfer within this important, naturally competent organism. Here, we report the complete annotated genome sequence of N. gonorrhoeae strain NCCP11945.

scholarly journals Direct Visualization of Horizontal Gene Transfer by Transformation in Live Pneumococcal Cells Using Microfluidics

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 675
Author(s):  
Isabelle Mortier-Barrière ◽  
Patrice Polard ◽  
Nathalie Campo
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Expression Profiles ◽  
Physiological State ◽  
Microfluidic System ◽  
Live Cells ◽  
Microfluidic Channels ◽  
Dna Uptake ◽  
Fluorescent Reporters ◽  
Natural Genetic Transformation

Natural genetic transformation is a programmed mechanism of horizontal gene transfer in bacteria. It requires the development of competence, a specialized physiological state during which proteins involved in DNA uptake and chromosomal integration are produced. In Streptococcus pneumoniae, competence is transient. It is controlled by a secreted peptide pheromone, the competence-stimulating peptide (CSP) that triggers the sequential transcription of two sets of genes termed early and late competence genes, respectively. Here, we used a microfluidic system with fluorescence microscopy to monitor pneumococcal competence development and transformation, in live cells at the single cell level. We present the conditions to grow this microaerophilic bacterium under continuous flow, with a similar doubling time as in batch liquid culture. We show that perfusion of CSP in the microfluidic chamber results in the same reduction of the growth rate of individual cells as observed in competent pneumococcal cultures. We also describe newly designed fluorescent reporters to distinguish the expression of competence genes with temporally distinct expression profiles. Finally, we exploit the microfluidic technology to inject both CSP and transforming DNA in the microfluidic channels and perform near real time-tracking of transformation in live cells. We show that this approach is well suited to investigating the onset of pneumococcal competence together with the appearance and the fate of transformants in individual cells.

scholarly journals Horizontal gene transfer rate is not the primary determinant of observed antibiotic resistance frequencies in Streptococcus pneumoniae

2019 ◽  
Author(s):  
Sonja Lehtinen ◽  
Claire Chewapreecha ◽  
John Lees ◽  
William P. Hanage ◽  
Marc Lipsitch ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Streptococcus Pneumoniae ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Evolutionary Dynamics ◽  
Epidemiological Data ◽  
Unified Framework ◽  
Genetic Lineages ◽  
Pneumococcal Carriage ◽  
Primary Determinant

The extent to which evolution is constrained by the rate at which horizontal gene transfer (HGT) allows DNA to move between genetic lineages is an open question, which we address in the context of antibiotic resistance in Streptococcus pneumoniae. We analyze microbiological, genomic and epidemiological data from the largest-to-date sequenced pneumococcal carriage study in 955 infants from a refugee camp on the Thailand-Myanmar border. Using a unified framework, we simultaneously test prior hypotheses on rates of HGT and a key evolutionary covariate (duration of carriage) as determinants of resistance frequencies. We conclude that in this setting, there is only weak evidence for the rate of HGT playing a role in the evolutionary dynamics of resistance. Instead, observed resistance frequencies are best explained as the outcome of selection acting on a pool of variants, irrespective of the rate at which resistance determinants move between genetic lineages.

scholarly journals Generation of Genic Diversity among Streptococcus pneumoniae Strains via Horizontal Gene Transfer during a Chronic Polyclonal Pediatric Infection

2010 ◽  
Vol 6 (9) ◽  
pp. e1001108 ◽  
Author(s):  
N. Luisa Hiller ◽  
Azad Ahmed ◽  
Evan Powell ◽  
Darren P. Martin ◽  
Rory Eutsey ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Genic Diversity ◽  
Pediatric Infection

scholarly journals TheblpLocus of Streptococcus pneumoniae Plays a Limited Role in the Selection of Strains That Can Cocolonize the Human Nasopharynx

2016 ◽  
Vol 82 (17) ◽  
pp. 5206-5215 ◽  
Author(s):  
Carina Valente ◽  
Suzanne Dawid ◽  
Francisco R. Pinto ◽  
Jason Hinds ◽  
Alexandra S. Simões ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Experimental Models ◽  
Nasopharyngeal Colonization ◽  
Content Type ◽  
Limited Role ◽  
Multiple Strains ◽  
The Impact

ABSTRACTNasopharyngeal colonization is important forStreptococcus pneumoniaeevolution, providing the opportunity for horizontal gene transfer when multiple strains co-occur. Although colonization with more than one strain of pneumococcus is common, the factors that influence the ability of strains to coexist are not known. A highly variableblp(bacteriocin-like peptide) locus has been identified in all sequenced strains ofS. pneumoniae. This locus controls the regulation and secretion of bacteriocins, small peptides that target other bacteria. In this study, we analyzed a series of cocolonizing isolates to evaluate the impact of theblplocus on human colonization to determine whether competitive phenotypes of bacteriocin secretion restrict cocolonization. We identified a collection of 135 nasopharyngeal samples cocolonized with two or more strains, totaling 285 isolates. Theblplocus of all strains was characterized genetically with regard to pheromone type, bacteriocin/immunity content, and potential for locus functionality. Inhibitory phenotypes of bacteriocin secretion and locus activity were assessed through overlay assays. Isolates from single colonizations (n= 298) were characterized for comparison. Cocolonizing strains had a high diversity ofblpcassettes; approximately one-third displayed an inhibitory phenotypein vitro. Despitein vitroevidence of competition, pneumococci cocolonized the subjects independently ofblppheromone type (P= 0.577), bacteriocin/immunity content,blplocus activity (P= 0.798), and inhibitory phenotype (P= 0.716). In addition, no significant differences were observed when single and cocolonizing strains were compared. Despite clear evidence ofblp-mediated competition in experimental models, the results of our study suggest that theblplocus plays a limited role in restricting pneumococcal cocolonization in humans.IMPORTANCENasopharyngeal colonization withStreptococcus pneumoniae(pneumococcus) is important for pneumococcal evolution, as the nasopharynx represents the major site for horizontal gene transfer when multiple strains co-occur, a phenomenon known as cocolonization. Understanding how pneumococcal strains interact within the competitive environment of the nasopharynx is of chief importance in the context of pneumococcal ecology. In this study, we used an unbiased collection of naturally co-occurring pneumococcal strains and showed that a biological process frequently used by bacteria for competition—bacteriocin production—is not decisive in the coexistence of pneumococci in the host, in contrast to what has been shown in experimental models.

scholarly journals Horizontal gene transfer rate is not the primary determinant of observed antibiotic resistance frequencies in Streptococcus pneumoniae

2020 ◽  
Vol 6 (21) ◽  
pp. eaaz6137 ◽  
Author(s):  
Sonja Lehtinen ◽  
Claire Chewapreecha ◽  
John Lees ◽  
William P. Hanage ◽  
Marc Lipsitch ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Streptococcus Pneumoniae ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Epidemiological Data ◽  
Unified Framework ◽  
Genetic Lineages ◽  
Pneumococcal Carriage ◽  
Primary Determinant ◽  
Open Question

The extent to which evolution is constrained by the rate at which horizontal gene transfer (HGT) allows DNA to move between genetic lineages is an open question, which we address in the context of antibiotic resistance in Streptococcus pneumoniae. We analyze microbiological, genomic, and epidemiological data from the largest-to-date sequenced pneumococcal carriage study in 955 infants from a refugee camp on the Thailand-Myanmar border. Using a unified framework, we simultaneously test prior hypotheses on rates of HGT and a key evolutionary covariate (duration of carriage) as determinants of resistance frequencies. We conclude that in this setting, there is little evidence of HGT playing a major role in determining resistance frequencies. Instead, observed resistance frequencies are best explained as the outcome of selection acting on a pool of variants, irrespective of the rate at which resistance determinants move between genetic lineages.

A kinetic model of gene transfer via natural transformation of Azotobacter vinelandii

2015 ◽  
Vol 1 (3) ◽  
pp. 363-374 ◽  
Author(s):  
Nanxi Lu ◽  
Arash Massoudieh ◽  
Xiaomeng Liang ◽  
Tamir Kamai ◽  
Julie L. Zilles ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Kinetic Model ◽  
Aquatic Environment ◽  
Natural Transformation ◽  
Azotobacter Vinelandii ◽  
Genetic Traits

Horizontal gene transfer allows antibiotic resistance and other genetic traits to spread among bacteria in the aquatic environment.

Sign in / Sign up

Export Citation Format

Share Document