Search results for "conjugation"

A Selenium-Nitrogen Chain with Selenium in Different Oxidation States

2017

Conjugation is necessary for a bacterial plasmid to survive under protozoan predation

2016

Horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. Interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. Here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid RP4 in populations of the opportunist bacterial pathogenSerratia marcescens. A conjugation-defective mutant plasmid was unable to survive under predation, suggesting that conjugative transfer is required for plasmid persistence under the realistic condition of predation. These results indicate that multi-trophic interactions can affect the maintenance of con…

Alkyne-Functionalized Coumarin Compound for Analytic and Preparative 4-Thiouridine Labeling

2017

Bioconjugation of RNA is a dynamic field recently reinvigorated by a surge in research on post-transcriptional modification. This work focuses on the bioconjugation of 4-thiouridine, a nucleoside that occurs as a post-transcriptional modification in bacterial RNA and is used as a metabolic label and for cross-linking purposes in eukaryotic RNA. A newly designed coumarin compound named 4-bromomethyl-7-propargyloxycoumarin (PBC) is introduced, which exhibits remarkable selectivity for 4-thiouridine. Bearing a terminal alkyne group, it is conductive to secondary bioconjugation via “click chemistry”, thereby offering a wide range of preparative and analytical options. We applied PBC to quantita…

Conjugative ESBL plasmids differ in their potential to rescue susceptible bacteria via horizontal gene transfer in lethal antibiotic concentrations.

2017

Conjugative ESBL plasmids differ in their potential to rescue susceptible bacteria via horizontal gene transfer in lethal antibiotic concentrations

Scoping the effectiveness and evolutionary obstacles in using plasmid-dependent phages to fight antibiotic resistance

2016

Aim: To investigate the potential evolutionary obstacles in the sustainable therapeutic use of plasmid-dependent phages to control the clinically important conjugative plasmid-mediated dissemination of antibiotic resistance genes to pathogenic bacteria. Materials & methods: The lytic plasmid-dependent phage PRD1 and the multiresistance conferring plasmid RP4 in an Escherichia coli host were utilized to assess the genetic and phenotypic changes induced by combined phage and antibiotic selection. Results & conclusions: Resistance to PRD1 was always coupled with either completely lost or greatly reduced conjugation ability. Reversion to full conjugation efficiency was found to be rare…

Protein-Free Hapten-Carbon Nanotube Constructs Induce the Secondary Immune Response

2017

Carbon nanotubes are novel technological tools with multiple applications. The interaction between such nanoparticles and living organisms is nowadays a matter of keen research by academic and private institutions. In this study, carbon nanotube constructs were investigated as delivery vehicles for immunostimulation and induction of the secondary immune response to a small organic molecule, namely, a hapten. Two types of nanoconstructs were prepared: on one hand, carbon nanotubes carrying a protein bioconjugate of a hapten covalently linked to the carbon surface, and on the other hand, covalent carbon nanotube constructs of the same model chemical compound without the carrier protein. Nanot…

Functional comparison of bacteria from the human gut and closely related non-gut bacteria reveals the importance of conjugation and a paucity of moti…

2016

International audience; The human GI tract is a complex and still poorly understood environment, inhabited by one of the densest microbial communities on earth. The gut microbiota is shaped by millennia of evolution to co-exist with the host in commensal or symbiotic relationships. Members of the gut microbiota perform specific molecular functions important in the human gut environment. This can be illustrated by the presence of a highly expanded repertoire of proteins involved in carbohydrate metabolism, in phase with the large diversity of polysaccharides originating from the diet or from the host itself that can be encountered in this environment. In order to identify other bacterial fun…

Transcriptome analysis revealed that a quorum sensing system regulates the transfer of the pAt megaplasmid in Agrobacterium tumefaciens.

2016

Background Agrobacterium tumefaciens strain P4 is atypical, as the strain is not pathogenic and produces a for this species unusual quorum sensing signal, identified as N-(3-hydroxy-octanoyl)-homoserine lactone (3OH,C8-HSL). Results By sequence analysis and cloning, a functional luxI-like gene, named cinI, has been identified on the At plasmid of A. tumefaciens strain P4. Insertion mutagenesis in the cinI gene and transcriptome analyses permitted the identification of 32 cinI-regulated genes in this strain, most of them encoding proteins responsible for the conjugative transfer of pAtP4. Among these genes were the avhB genes that encode a type 4 secretion system (T4SS) involved in the forma…

Arabidopsis TCP Transcription Factors Interact with the SUMO Conjugating Machinery in Nuclear Foci

2017

In Arabidopsis more than 400 proteins have been identified as SUMO targets, both in vivo and in vitro. Among others, transcription factors (TFs) are common targets for SUMO conjugation. Here we aimed to exhaustively screen for TFs that interact with the SUMO machinery using an arrayed yeast two-hybrid library containing more than 1,100 TFs. We identified 76 interactors that foremost interact with the SUMO conjugation enzyme SCE1 and/or the SUMO E3 ligase SIZ1. These interactors belong to various TF families, which control a wide range of processes in plant development and stress signaling. Amongst these interactors, the TCP family was overrepresented with several TCPs interacting with diffe…

Biological Peer-To-Peer Networks: From Bacterial Communication To The Development Of Synthetic Distributed Systems

2014

We address Bacterial Computing from the study of bacterial communication mechanisms, by assuming a conceptual framework between Computer Science and Biology in which cells are conceived as nodes. This nodes process information through modules formed of DNA as encoded software (biobricks) and are connected to other nodes. In order to understand how peerto-peer mechanisms operate in bacteria, we have studied Quorum sensing and Conjugation with an engineering perspective. Learning how cells process and exchange information we try to glimpse new theoretical approaches to develop synthetic networks and to transfer complex algorithms to natural environments. Extending bacterial communications we …