Real-time visualisation of the intracellular dynamics of conjugative plasmid transfer.

Conjugation is a contact-dependent mechanism for the transfer of plasmid DNA between bacterial cells, which contributes to the dissemination of antibiotic resistance. Here, we use live-cell microscopy to visualise the intracellular dynamics of conjugative transfer of F-plasmid in E. coli, in real time.

AES and ToF-SIMS combination for single cell chemical imaging of gold nanoparticle-labeled .

A chemical fingerprint of the Escherichia coli cell surface labeled by gelatin coated gold nanoparticles was obtained by combining Auger Electron Spectroscopy (AES) for single cell level chemical images, and Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) Tandem MS for unambiguous molecular identification of co-localized species.

Direct visualisation of drug-efflux in live Escherichia coli cells.

Drug-efflux by pump proteins is one of the major mechanisms of antibiotic resistance in bacteria. Here, we use quantitative fluorescence microscopy to investigate the real-time dynamics of drug accumulation and efflux in live E. coli cells.

Role of AcrAB-TolC multidrug efflux pump in drug-resistance acquisition by plasmid transfer.

Drug-resistance dissemination by horizontal gene transfer remains poorly understood at the cellular scale. Using live-cell microscopy, we reveal the dynamics of resistance acquisition by transfer of the fertility factor-conjugation plasmid encoding the tetracycline-efflux pump TetA. The entry of the single-stranded DNA plasmid into the recipient cell is rapidly followed by complementary-strand synthesis, plasmid-gene expression, and production of TetA.

MatP regulates the coordinated action of topoisomerase IV and MukBEF in chromosome segregation.

The Escherichia coli SMC complex, MukBEF, forms clusters of molecules that interact with the decatenase topisomerase IV and which are normally associated with the chromosome replication origin region (ori). Here we demonstrate an additional ATP-hydrolysis-dependent association of MukBEF with the replication termination region (ter). Consistent with this, MukBEF interacts with MatP, which binds matS sites in ter.

The bacterial chromosome: architecture and action of bacterial SMC and SMC-like complexes.

Structural Maintenance of Chromosomes (SMC) protein complexes are found in all three domains of life. They are characterized by a distinctive and conserved architecture in which a globular ATPase 'head' domain is formed by the N- and C-terminal regions of the SMC protein coming together, with a c. 50-nm-long antiparallel coiled-coil separating the head from a dimerization 'hinge'.

Co-evolution of segregation guide DNA motifs and the FtsK translocase in bacteria: identification of the atypical Lactococcus lactis KOPS motif.

Bacteria use the global bipolarization of their chromosomes into replichores to control the dynamics and segregation of their genome during the cell cycle. This involves the control of protein activities by recognition of specific short DNA motifs whose orientation along the chromosome is highly skewed. The KOPS motifs act in chromosome segregation by orienting the activity of the FtsK DNA translocase towards the terminal replichore junction.

Are two better than one? Analysis of an FtsK/Xer recombination system that uses a single recombinase.

Bacteria harbouring circular chromosomes have a Xer site-specific recombination system that resolves chromosome dimers at division. In Escherichia coli, the activity of the XerCD/dif system is controlled and coupled with cell division by the FtsK DNA translocase. Most Xer systems, as XerCD/dif, include two different recombinases.

The K-loop, a general feature of the Pyrococcus C/D guide RNAs, is an RNA structural motif related to the K-turn.

The C/D guide RNAs predicted from the genomic sequences of three species of Pyrococcus delineate a family of small non-coding archaeal RNAs involved in the methylation of rRNA and tRNA. The C/D guides assemble into ribonucleoprotein (RNP) that contains the methyltransferase. The protein L7Ae, a key structural component of the RNP, binds to a Kink-turn (K-turn) formed by the C/D motif.