scholarly journals Molecular Mechanisms Influencing Bacterial Conjugation in the Intestinal Microbiota

2021 ◽  
Vol 12 ◽  
Author(s):  
Kevin Neil ◽  
Nancy Allard ◽  
Sébastien Rodrigue
Keyword(s):  
Intestinal Microbiota ◽  
Molecular Mechanisms ◽  
Antibiotic Resistance Genes ◽  
Dna Transfer ◽  
Conjugative Plasmid ◽  
Microbial Populations ◽  
Bacterial Conjugation ◽  
Mating Pair ◽  
Dense Population ◽  
Factors Influencing

Bacterial conjugation is a widespread and particularly efficient strategy to horizontally disseminate genes in microbial populations. With a rich and dense population of microorganisms, the intestinal microbiota is often considered a fertile environment for conjugative transfer and a major reservoir of antibiotic resistance genes. In this mini-review, we summarize recent findings suggesting that few conjugative plasmid families present in Enterobacteriaceae transfer at high rates in the gut microbiota. We discuss the importance of mating pair stabilization as well as additional factors influencing DNA transfer efficiency and conjugative host range in this environment. Finally, we examine the potential repurposing of bacterial conjugation for microbiome editing.

scholarly journals Bacterial Conjugation in the Cytoplasm of Mouse Cells

2008 ◽  
Vol 76 (11) ◽  
pp. 5110-5119 ◽  
Author(s):  
Yin Mei Lim ◽  
Ad J. C. de Groof ◽  
Mrinal K. Bhattacharjee ◽  
David H. Figurski ◽  
Eric A. Schon
Keyword(s):  
High Frequency ◽  
Mammalian Cells ◽  
Yersinia Pseudotuberculosis ◽  
Shigella Flexneri ◽  
Antibiotic Resistance Genes ◽  
Conjugative Plasmid ◽  
Bacterial Conjugation ◽  
3T3 Cells ◽  
Transfer Genes ◽  
Mouse Cells

ABSTRACT Intracellular pathogenic organisms such as salmonellae and shigellae are able to evade the effects of many antibiotics because the drugs are not able to penetrate the plasma membrane. In addition, these bacteria may be able to transfer genes within cells while protected from the action of drugs. The primary mode by which virulence and antibiotic resistance genes are spread is bacterial conjugation. Salmonellae have been shown to be competent for conjugation in the vacuoles of cultured mammalian cells. We now show that the conjugation machinery is also functional in the mammalian cytosol. Specially constructed Escherichia coli strains expressing Shigella flexneri plasmid and chromosomal virulence factors for escape from vacuoles and synthesizing the invasin protein from Yersinia pseudotuberculosis to enhance cellular entry were able to enter 3T3 cells and escape from the phagocytic vacuole. One bacterial strain (the donor) of each pair to be introduced sequentially into mammalian cells had a conjugative plasmid. We found that this plasmid could be transferred at high frequency. Conjugation in the cytoplasm of cells may well be a general phenomenon.

scholarly journals Monitoring Bacterial Conjugation by Optical Microscopy

2021 ◽  
Vol 12 ◽  
Author(s):  
Gerardo Carranza ◽  
Tamara Menguiano ◽  
Fernando Valenzuela-Gómez ◽  
Yolanda García-Cazorla ◽  
Elena Cabezón ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Optical Microscopy ◽  
Resistance Genes ◽  
Fluorescent Protein ◽  
Antibiotic Resistance Genes ◽  
Conjugative Plasmid ◽  
Bacterial Conjugation ◽  
Transfer Device

Bacterial conjugation is the main mechanism for horizontal gene transfer, conferring plasticity to the genome repertoire. This process is also the major instrument for the dissemination of antibiotic resistance genes. Hence, gathering primary information of the mechanism underlying this genetic transaction is of a capital interest. By using fluorescent protein fusions to the ATPases that power conjugation, we have been able to track the localization of these proteins in the presence and absence of recipient cells. Moreover, we have found that more than one copy of the conjugative plasmid is transferred during mating. Altogether, these findings provide new insights into the mechanism of such an important gene transfer device.

scholarly journals Initiation and Termination of DNA Transfer during Conjugation of IncI1 Plasmid R64: Roles of Two Sets of Inverted Repeat Sequences within oriT in Termination of R64 Transfer

2000 ◽  
Vol 182 (11) ◽  
pp. 3191-3196 ◽  
Author(s):  
Nobuhisa Furuya ◽  
Teruya Komano
Keyword(s):  
Inverted Repeat ◽  
Dna Transfer ◽  
Conjugative Plasmid ◽  
Bacterial Conjugation ◽  
Binding Ability ◽  
Rolling Circle ◽  
Region Sequence ◽  
Repeat Sequences ◽  
Plasmid R64 ◽  
Termination Process

ABSTRACT Intercellular transfer of plasmid DNA during bacterial conjugation initiates and terminates at a specific origin of transfer,oriT. We have investigated the oriT structure of conjugative plasmid R64 with regard to the initiation and termination of DNA transfer. Using recombinant plasmids containing two tandemly repeated R64 oriT sequences with or without mutations, the subregions required for initiation and termination were determined by examining conjugation-mediated deletion between the repeated oriTs. The oriT subregion required for initiation was found to be identical to the 44-bp oriT core sequence consisting of two units, the conserved nick region sequence and the 17-bp repeat A sequence, that are recognized by R64 relaxosome proteins NikB and NikA, respectively. In contrast, the nick region sequence and two sets of inverted repeat sequences within the 92-bp minimal oriT sequence were required for efficient termination. Mutant repeat A sequences lacking NikA-binding ability were found to be sufficient for termination, suggesting that the inverted repeat structures are involved in the termination process. A duplication of the DNA segment between the repeated oriTs was also found after mobilization of the plasmid carrying initiation-deficient but termination-proficient oriT and initiation-proficient but termination-deficient oriT, suggesting that the 3′ terminus of the transferred strand is elongated by rolling-circle-DNA synthesis.

scholarly journals Isolation and Characterization of cLV25, a Bacteroides fragilis Chromosomal Transfer Factor Resembling Multiple Bacteroides sp. Mobilizable Transposons

2002 ◽  
Vol 184 (7) ◽  
pp. 1895-1904 ◽  
Author(s):  
Kathleen A. Bass ◽  
David W. Hecht
Keyword(s):  
Transfer Factor ◽  
Sequence Similarity ◽  
Shuttle Vector ◽  
Bacteroides Fragilis ◽  
Antibiotic Resistance Genes ◽  
Dna Transfer ◽  
Conjugative Plasmid ◽  
Significant Similarity ◽  
Transfer Factors ◽  
Isolation And Characterization

ABSTRACT Horizontal DNA transfer contributes significantly to the dissemination of antibiotic resistance genes in Bacteroides fragilis. To further our understanding of DNA transfer in B. fragilis, we isolated and characterized a new transfer factor, cLV25. cLV25 was isolated from B. fragilis LV25 by its capture on the nonmobilizable Escherichia coli-Bacteroides shuttle vector pGAT400ΔBglII. Similar to other Bacteroides sp. transfer factors, cLV25 was mobilized in E. coli by the conjugative plasmid R751. Using Tn1000 mutagenesis and deletion analysis of cLV25, two mobilization genes, bmgA and bmgB, were identified, whose predicted proteins have similarity to DNA relaxases and mobilization proteins, respectively. In particular, BmgA and BmgB were homologous to MocA and MocB, respectively, the two mobilization proteins of the B. fragilis mobilizable transposon Tn4399. A cis-acting origin of transfer (oriT) was localized to a 353-bp region that included nearly all of the intergenic region between bmgB and orf22 and overlapped with the 3′ end of orf22. This oriT contained a putative nic site sequence but showed no significant similarity to the oriT regions of other transfer factors, including Tn4399. Despite the lack of sequence similarity between the oriTs of cLV25 and Tn4399, a mutation in the cLV25 putative DNA relaxase, bmgA, was partially complemented by Tn4399. In addition to the functional cross-reaction with Tn4399, a second distinguishing feature of cLV25 is that predicted proteins have similarity to proteins encoded not only by Tn4399 but by several Bacteroides sp. transfer factors, including NBU1, NBU2, CTnDOT, Tn4555, and Tn5520.

scholarly journals Functional Characterization of IS1999, an IS4 Family Element Involved in Mobilization and Expression of β-Lactam Resistance Genes

2006 ◽  
Vol 188 (18) ◽  
pp. 6506-6514 ◽  
Author(s):  
Daniel Aubert ◽  
Thierry Naas ◽  
Claire Héritier ◽  
Laurent Poirel ◽  
Patrice Nordmann
Keyword(s):  
Resistance Genes ◽  
Consensus Sequence ◽  
Functional Characterization ◽  
Antibiotic Resistance Genes ◽  
Conjugative Plasmid ◽  
Transposition Frequency ◽  
Transposase Gene ◽  
Reverse Transcription Pcr ◽  
Mutant Derivative ◽  
Rapid Amplification

ABSTRACT IS1999 and a point mutant derivative, IS1999.2, have been described inserted upstream of emerging antibiotic resistance genes bla VEB-1 and bla OXA-48. 5′ Rapid amplification of cDNA ends experiments revealed that expression of these β-lactamase genes was driven by the outward-directed promoter, Pout, located in the IS1999 elements. These findings led us to study IS1999-mediated gene mobilization. Thus, the transposition properties of IS1999 and of IS1999-based composite transposons, made of two copies of IS1999 in different orientations, were investigated. IS1999 or IS1999-based composite transposons were capable of transposing onto the conjugative plasmid pOX38-Gen. Sequence analysis of the insertion sites revealed that IS1999 inserted preferentially into DNA targets containing the consensus sequence NGCNNNGCN. Transposition was more efficient when at least one left inverted repeat end was located at an outside end of the transposon. The transposition frequency of IS1999.2 was 10-fold lower than that of IS1999, and transposition frequencies of the putative natural transposon, Tn1999, were below detection limits of our transposition assay. This reduced transposition frequency of IS1999.2-based elements may result from a lower transcription of the transposase gene, as revealed by reverse transcription-PCR analyses.

Factors Influencing T-DNA Transfer into Wheat and Barley Cells by Agrobacterium Tumefaciens

1998 ◽  
Vol 26 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Guangqin Guo ◽  
Frank Maiwald ◽  
Petra Lorenzen ◽  
Hans-Henning Steinbiss
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Dna Transfer ◽  
Factors Influencing

scholarly journals Modeling Diet-Induced NAFLD and NASH in Rats: A Comprehensive Review

Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 378
Author(s):  
Lydie Carreres ◽  
Zuzana Macek Jílková ◽  
Guillaume Vial ◽  
Patrice N. Marche ◽  
Thomas Decaens ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver Disease ◽  
Molecular Mechanisms ◽  
Preclinical Study ◽  
External Factors ◽  
Important Research ◽  
Research Activity ◽  
Nonalcoholic Fatty Liver ◽  
Rat Models ◽  
Factors Influencing

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, characterized by hepatic steatosis without any alcohol abuse. As the prevalence of NAFLD is rapidly increasing worldwide, important research activity is being dedicated to deciphering the underlying molecular mechanisms in order to define new therapeutic targets. To investigate these pathways and validate preclinical study, reliable, simple and reproducible tools are needed. For that purpose, animal models, more precisely, diet-induced NAFLD and nonalcoholic steatohepatitis (NASH) models, were developed to mimic the human disease. In this review, we focus on rat models, especially in the current investigation of the establishment of the dietary model of NAFLD and NASH in this species, compiling the different dietary compositions and their impact on histological outcomes and metabolic injuries, as well as external factors influencing the course of liver pathogenesis.

scholarly journals Complete Nucleotide Sequence of the pCTX-M3 Plasmid and Its Involvement in Spread of the Extended-Spectrum β-Lactamase Gene blaCTX-M-3

2007 ◽  
Vol 51 (11) ◽  
pp. 3789-3795 ◽  
Author(s):  
M. Gołębiewski ◽  
I. Kern-Zdanowicz ◽  
M. Zienkiewicz ◽  
M. Adamczyk ◽  
J. Żyliǹska ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Conjugative Plasmid ◽  
Bacterial Strains ◽  
Extended Spectrum ◽  
Gene Coding ◽  
Kluyvera Ascorbata ◽  
Almost All ◽  
Lactamase Gene

ABSTRACT Here we report the nucleotide sequence of pCTX-M3, a highly conjugative plasmid that is responsible for the extensive spread of the gene coding for the CTX-M-3 extended-spectrum β-lactamase in clinical populations of the family Enterobacteriaceae in Poland. The plasmid belongs to the IncL/M incompatibility group, is 89,468 bp in size, and carries 103 putative genes. Besides bla CTX-M-3, it also bears the bla TEM-1, aacC2, and armA genes, as well as integronic aadA2, dfrA12, and sul1, which altogether confer resistance to the majority of β-lactams and aminoglycosides and to trimethoprim-sulfamethoxazole. The conjugal transfer genes are organized in two blocks, tra and trb, separated by a spacer sequence where almost all antibiotic resistance genes and multiple mobile genetic elements are located. Only bla CTX-M-3, accompanied by an ISEcp1 element, is placed separately, in a DNA fragment previously identified as a fragment of the Kluyvera ascorbata chromosome. On the basis of sequence analysis, we speculate that pCTX-M3 might have arisen from plasmid pEL60 from plant pathogen Erwinia amylovora by acquiring mobile elements with resistance genes. This suggests that plasmids of environmental bacterial strains could be the source of those plasmids now observed in bacteria pathogenic for humans.

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