Binding of exogenous DNA to marine sediments and the effect of DNA/sediment binding on natural transformation of Pseudomonas stutzeri strain ZoBell in sediment columns

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.

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CryoEM structure of the type IVa pilus secretin required for natural competence in Vibrio cholerae

Nature Communications ◽

10.1038/s41467-020-18866-y ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Sara J. Weaver ◽

Davi R. Ortega ◽

Matthew H. Sazinsky ◽

Triana N. Dalia ◽

Ankur B. Dalia ◽

...

Keyword(s):

Antibiotic Resistance ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Vibrio Cholerae ◽

Natural Transformation ◽

Domain Architecture ◽

Genetic Material ◽

Surface Binding ◽

Exogenous Dna ◽

Insight Into

Abstract Natural transformation is the process by which bacteria take up genetic material from their environment and integrate it into their genome by homologous recombination. It represents one mode of horizontal gene transfer and contributes to the spread of traits like antibiotic resistance. In Vibrio cholerae, a type IVa pilus (T4aP) is thought to facilitate natural transformation by extending from the cell surface, binding to exogenous DNA, and retracting to thread this DNA through the outer membrane secretin, PilQ. Here, we use a functional tagged allele of VcPilQ purified from native V. cholerae cells to determine the cryoEM structure of the VcPilQ secretin in amphipol to ~2.7 Å. We use bioinformatics to examine the domain architecture and gene neighborhood of T4aP secretins in Proteobacteria in comparison with VcPilQ. This structure highlights differences in the architecture of the T4aP secretin from the type II and type III secretion system secretins. Based on our cryoEM structure, we design a series of mutants to reversibly regulate VcPilQ gate dynamics. These experiments support the idea of VcPilQ as a potential druggable target and provide insight into the channel that DNA likely traverses to promote the spread of antibiotic resistance via horizontal gene transfer by natural transformation.

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Silencing of natural transformation by an RNA chaperone and a multitarget small RNA

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1601626113 ◽

2016 ◽

Vol 113 (31) ◽

pp. 8813-8818 ◽

Cited By ~ 60

Author(s):

Laetitia Attaiech ◽

Aïda Boughammoura ◽

Céline Brochier-Armanet ◽

Omran Allatif ◽

Flora Peillard-Fiorente ◽

...

Keyword(s):

Legionella Pneumophila ◽

Natural Transformation ◽

Bacterial Species ◽

Physiological State ◽

Uptake System ◽

Dna Uptake ◽

Exogenous Dna ◽

Major Mechanism ◽

Transcriptional Gene Regulation ◽

High Level

A highly conserved DNA uptake system allows many bacteria to actively import and integrate exogenous DNA. This process, called natural transformation, represents a major mechanism of horizontal gene transfer (HGT) involved in the acquisition of virulence and antibiotic resistance determinants. Despite evidence of HGT and the high level of conservation of the genes coding the DNA uptake system, most bacterial species appear non-transformable under laboratory conditions. In naturally transformable species, the DNA uptake system is only expressed when bacteria enter a physiological state called competence, which develops under specific conditions. Here, we investigated the mechanism that controls expression of the DNA uptake system in the human pathogenLegionella pneumophila. We found that a repressor of this system displays a conserved ProQ/FinO domain and interacts with a newly characterizedtrans-acting sRNA, RocR. Together, they target mRNAs of the genes coding the DNA uptake system to control natural transformation. This RNA-based silencing represents a previously unknown regulatory means to control this major mechanism of HGT. Importantly, these findings also show that chromosome-encoded ProQ/FinO domain-containing proteins can assisttrans-acting sRNAs and that this class of RNA chaperones could play key roles in post-transcriptional gene regulation throughout bacterial species.

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Natural transformation of Pseudomonas stutzeri by plasmids that contain cloned fragments of chromosomal deoxyribonucleic acid

Archives of Microbiology ◽

10.1007/bf00454915 ◽

1984 ◽

Vol 140 (2-3) ◽

pp. 134-138 ◽

Cited By ~ 13

Author(s):

Curtis A. Carlson ◽

Susan M. Steenbergen ◽

John L. Ingraham

Keyword(s):

Deoxyribonucleic Acid ◽

Natural Transformation ◽

Pseudomonas Stutzeri

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Biology of Pseudomonas stutzeri

Microbiology and Molecular Biology Reviews ◽

10.1128/mmbr.00047-05 ◽

2006 ◽

Vol 70 (2) ◽

pp. 510-547 ◽

Cited By ~ 315

Author(s):

Jorge Lalucat ◽

Antoni Bennasar ◽

Rafael Bosch ◽

Elena García-Valdés ◽

Norberto J. Palleroni

Keyword(s):

Natural Transformation ◽

Model Organism ◽

Pseudomonas Stutzeri ◽

Opportunistic Pathogen ◽

Denitrifying Bacterium ◽

The Past ◽

History Of ◽

Metabolic Properties ◽

Degradation Of Pollutants ◽

Made In

SUMMARY Pseudomonas stutzeri is a nonfluorescent denitrifying bacterium widely distributed in the environment, and it has also been isolated as an opportunistic pathogen from humans. Over the past 15 years, much progress has been made in elucidating the taxonomy of this diverse taxonomical group, demonstrating the clonality of its populations. The species has received much attention because of its particular metabolic properties: it has been proposed as a model organism for denitrification studies; many strains have natural transformation properties, making it relevant for study of the transfer of genes in the environment; several strains are able to fix dinitrogen; and others participate in the degradation of pollutants or interact with toxic metals. This review considers the history of the discovery, nomenclatural changes, and early studies, together with the relevant biological and ecological properties, of P. stutzeri.

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CryoEM structure of the Vibrio cholerae Type IV competence pilus secretin PilQ

10.1101/2020.03.03.975896 ◽

2020 ◽

Cited By ~ 1

Author(s):

Sara J. Weaver ◽

Matthew H. Sazinsky ◽

Triana N. Dalia ◽

Ankur B. Dalia ◽

Grant J. Jensen

Keyword(s):

Antibiotic Resistance ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Vibrio Cholerae ◽

Natural Transformation ◽

Structural Information ◽

Genetic Material ◽

Surface Binding ◽

Exogenous Dna ◽

Type Iv

AbstractNatural transformation is the process by which bacteria take up genetic material from their environment and integrate it into their genome by homologous recombination. It represents one mode of horizontal gene transfer and contributes to the spread of traits like antibiotic resistance. In Vibrio cholerae, the Type IV competence pilus is thought to facilitate natural transformation by extending from the cell surface, binding to exogenous DNA, and retracting to thread this DNA through the outer membrane secretin, PilQ. A lack of structural information has hindered our understanding of this process, however. Here, we solved the first ever high-resolution structure of a Type IV competence pilus secretin. A functional tagged allele of VcPilQ purified from native V. cholerae cells was used to determine the cryoEM structure of the PilQ secretin in amphipol to ∼2.7 Å. This structure highlights for the first time key differences in the architecture of the Type IV competence pilus secretin from the Type II and Type III Secretin System secretins. Based on our cryoEM structure, we designed a series of mutants to interrogate the mechanism of PilQ. These experiments provide insight into the channel that DNA likely traverses to promote the spread of antibiotic resistance via horizontal gene transfer by natural transformation. We prove that it is possible to reduce pilus biogenesis and natural transformation by sealing the gate, suggesting VcPilQ as a new drug target.

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