Dynamics of the IncW genetic backbone imply general trends in conjugative plasmid evolution.

Plasmids cannot be understood as mere tools for genetic exchange: they are themselves subject to the forces of evolution. Their genomic and phylogenetic features have been less studied in this respect. Focusing on the IncW incompatibility group, which includes the smallest known conjugative plasmids, we attempt to unveil some common trends in plasmid evolution.

Transcription modulation of Salmonella enterica serovar Typhimurium promoters by sub-MIC levels of rifampin.

Promoter-lux fusions that showed rifampin-modulated transcription were identified from a Salmonella enterica serovar Typhimurium 14028 reporter library. The transformation of a subset of fusions into mutants that lacked one of six global regulatory proteins or were rifampin resistant showed that transcription modulation was independent of the global regulators, promoter specific, and dependent on the interaction of rifampin with RNA polymerase.

The relaxase of the Rhizobium etli symbiotic plasmid shows nic site cis-acting preference.

Genetic and biochemical characterization of TraA, the relaxase of symbiotic plasmid pRetCFN42d from Rhizobium etli, is described. After purifying the relaxase domain (N265TraA), we demonstrated nic binding and cleavage activity in vitro and thus characterized for the first time the nick site (nic) of a plasmid in the family Rhizobiaceae. We studied the range of N265TraA relaxase specificity in vitro by testing different oligonucleotides in binding and nicking assays.

The transmembrane domain provides nucleotide binding specificity to the bacterial conjugation protein TrwB.

In order to understand the functional significance of the transmembrane domain of TrwB, an integral membrane protein involved in bacterial conjugation, the protein was purified in the native, and also as a truncated soluble form (TrwBDeltaN70). The intact protein (TrwB) binds preferentially purine over pyrimidine nucleotides, NTPs over NDPs, and ribo- over deoxyribonucleotides. In contrast, TrwBDeltaN70 binds uniformly all tested nucleotides.

Immobility response elicited by clamping the neck induces antinociception in a "tonic pain" test in mice.

Clamping the neck followed by body inversion to a supine position in mice elicits an immobility response called immobility by clamping the neck (ICN). The noxious pinch to the scruff of the neck produces antinociception in "phasic pain" models (e.g.

Commensurability and stability in nonperiodic systems.

We have investigated the response of 3D Bi(2)Sr(2)CaCu(2)O(8) vortex structures to a weak perturbation induced by 2D Fe pinning structures acting on one extremity of vortex lines. The pinning patterns were nano-engineered at the sample surface by means of either a Bitter decoration of the vortex lattice or electron-beam lithography. The commensurability conditions between 2D rigid pinning potentials and 3D elastic structures with short-range positional and long-range orientational correlation have been experimentally determined.

Unveiling the molecular mechanism of a conjugative relaxase: The structure of TrwC complexed with a 27-mer DNA comprising the recognition hairpin and the cleavage site.

TrwC is a DNA strand transferase that catalyzes the initial and final stages of conjugative DNA transfer. We have solved the crystal structure of the N-terminal relaxase domain of TrwC in complex with a 27 base-long DNA oligonucleotide that contains both the recognition hairpin and the scissile phosphate. In addition, a series of ternary structures of protein-DNA complexes with different divalent cations at the active site have been solved.

TrwB: an F(1)-ATPase-like molecular motor involved in DNA transport during bacterial conjugation.

The mechanism by which TrwB acts as a DNA transporter in bacterial conjugation is analyzed. Based on a parallelism between TrwB and F(1)-ATPase, TrwB would use the energy derived from ATP hydrolysis to pump DNA through its central channel, in a manner similar to that used by F(1)-ATPase to produce a rotary movement of the central gamma-subunit.

Achromobacter xylosoxidans endophthalmitis diagnosed by polymerase chain reaction and gene sequencing.

Purpose: To report a patient with Achromobacter xylosoxidansendophthalmitis that was diagnosed using polymerase chain reaction and gene sequencing.

Methods: Case report. A patient with culture-negative endophthalmitis underwent an anterior chamber tap.

Unsaturated fatty acids are inhibitors of bacterial conjugation.

This report describes a high-throughput assay to identify substances that reduce the frequency of conjugation in Gram-negative bacteria. Bacterial conjugation is largely responsible for the spread of multiple antibiotic resistances in human pathogens. Conjugation inhibitors may provide a means to control the spread of antibiotic resistance.

Functional interactions between type IV secretion systems involved in DNA transfer and virulence.

This paper reports an analysis of the functional interactions between type IV secretion systems (T4SS) that are part of the conjugative machinery for horizontal DNA transfer (cT4SS), and T4SS involved in bacterial pathogenicity (pT4SS). The authors' previous work showed that a conjugative coupling protein (T4CP) interacts with the VirB10-type component of the T4SS in order to recruit the protein-DNA complex to the transporter for conjugative DNA transfer. This study now shows by two-hybrid analysis that conjugative T4CPs also interact with the VirB10 element of the pT4SS of Agrobacterium tumefaciens (At), Bartonella tribocorum (Bt) and Brucella suis (Bs).

Site-specific recombinase and integrase activities of a conjugative relaxase in recipient cells.

Conjugative relaxases are the proteins that initiate bacterial conjugation by a site-specific cleavage of the transferred DNA strand. In vitro, they show strand-transferase activity on single-stranded DNA, which suggests they may also be responsible for recircularization of the transferred DNA. In this work, we show that TrwC, the relaxase of plasmid R388, is fully functional in the recipient cell, as shown by complementation of an R388 trwC mutant in the recipient.

Cesarean plus anoxia at birth induces hyperresponsiveness to locomotor activity by dopamine D2 agonist.

Transient global anoxia after Cesarean birth in rats may produce alterations in the subcortical DA function and related behaviors. The reports only tested the behavioral changes induced by a general DA agonist, such as amphetamine or apomorphine, in adult rats. Here we investigated the role of perinatal anoxia on the locomotion induced by a specific dopamine (DA) agonist and its relation to the DA D1-like and D2-like receptors, measured by autoradiography at two different ages, prepubertal (35 days old, P35) and postpubertal (60 days old, P60).

Regulation of finP transcription by DNA adenine methylation in the virulence plasmid of Salmonella enterica.

DNA adenine methylase (Dam(-)) mutants of Salmonella enterica serovar Typhimurium contain reduced levels of FinP RNA encoded on the virulence plasmid. Dam methylation appears to regulate finP transcription, rather than FinP RNA stability or turnover. The finP promoter includes canonical -10 and -35 modules and depends on the sigma(70) factor.

TrwB, the coupling protein involved in DNA transport during bacterial conjugation, is a DNA-dependent ATPase.

Bacterial conjugation is an example of macromolecular trafficking between cells, based on the translocation of single-stranded DNA across membranes through a type IV secretion system. TrwBDeltaN70 is the soluble domain of TrwB, an essential integral membrane protein that couples the relaxosome (a nucleoprotein complex) to the DNA transport apparatus in plasmid R388 conjugation. TrwBDeltaN70 crystallographic structure revealed a hexamer with six equivalent subunits and a central channel.

Short-lasting impairment of temperature perception by high frequency rTMS of the sensorimotor cortex.

Objective: Repetitive transcranial magnetic stimulation (rTMS) has become a useful tool for investigating and even modulating human brain function. RTMS of the human motor cortex can produce changes in excitability that outlast the period of stimulation. To investigate the persistent effect of high-frequency rTMS of sensorimotor cortex (SM1) on somatosensory function.

Strain differences of dopamine receptor levels and dopamine related behaviors in rats.

Here we have investigated whether differences in levels of dopamine D1-like, D2-like receptors, dopamine D3 receptors, and dopamine transporter could be related to behaviors such as immobility response and locomotion between Wistar rats and Sprague-Dawley rats. The levels of the dopamine receptors and transporter were measured by autoradiographic study at the level of basal ganglia and the limbic subregion. The behavioral study was done by open-field and immobility response tests.

Bacterial conjugation: a potential tool for genomic engineering.

Bacterial conjugation is a mechanism for horizontal DNA transfer with potential for universal DNA delivery. The conjugal machinery can be separated into three functional modules: the relaxosome, the coupling protein, and a type IV protein secretion system. Module interchangeability among different conjugative systems opens up the possibility of "a la carte" engineering of DNA delivery into virtually any cell type.

Maternal Phenylketonuria Collaborative Study (MPKUCS)--the 'outliers'.

Analysis of outcome data from 305 of the 414 offspring from the Maternal Phenylketonuria Collaborative Study (MPKUCS), plus 70 control offspring, revealed significant deficits in the IQ (intelligence quotient), as measured by the Wechsler Intelligence Scale for Children--Revised (WISC-R), when maternal metabolic control during pregnancy was delayed and/or inadequate. There were, however, 23 'outliers' (7.5% of the 305) in which the offspring's intellectual IQ was worse (n =10) or better (n =13) than expected.

DNA binding properties of protein TrwA, a possible structural variant of the Arc repressor superfamily.

Conjugative DNA processing of plasmid R388 requires the concerted action of two proteins, the relaxase-helicase TrwC and the relaxase enhancer TrwA. TrwA can be aligned with DNA binding proteins belonging to the ribbon-helix-helix (RHH) protein family. To further analyse TrwA function, the structural domains of the protein have been identified and dissected by limited proteolysis.

Vortex nanoliquid in high-temperature superconductors.

Using a differential magneto-optical technique to visualize the flow of transport currents, we reveal a new delocalization line within the reversible vortex liquid region in the presence of a low density of columnar defects. This line separates a homogeneous vortex liquid, in which all the vortices are delocalized, from a heterogeneous "nanoliquid" phase, in which interconnected nanodroplets of vortex liquid are caged in the pores of a solid skeleton formed by vortices pinned on columnar defects. The nanoliquid phase displays high correlation along the columnar defects but no transverse critical current.

Coupling factors in macromolecular type-IV secretion machineries.

Type IV secretion systems (T4SSs) are bacterial multiprotein organelles specialised in the transfer of (nucleo)protein complexes across cell membranes. They are essential for conjugation, bacterial-induced tumour formation in plant cells, as observed in Agrobacterium, toxin secretion, like in Bordetella and Helicobacter, cell-to-cell translocation of virulence factors, and intracellular activity of mammalian pathogens like Legionella. By enabling conjugative DNA delivery, these systems contribute to the spread of antibiotic resistance genes among bacteria.

Smith predictor based-sliding mode controller for integrating processes with elevated deadtime.

An approach to control integrating processes with elevated deadtime using a Smith predictor sliding mode controller is presented. A PID sliding surface and an integrating first-order plus deadtime model have been used to synthesize the controller. Since the performance of existing controllers with a Smith predictor decrease in the presence of modeling errors, this paper presents a simple approach to combining the Smith predictor with the sliding mode concept, which is a proven, simple, and robust procedure.

A classification scheme for mobilization regions of bacterial plasmids.

Transmissible plasmids can be classified according to their mobilization ability, as being conjugative (self-transmissible) or mobilizable (transmissible only in the presence of additional conjugative functions). Naturally occurring mobilizable plasmids carry the genetic information necessary for relaxosome formation and processing, but lack the functions required for mating pair formation. Mobilizable plasmids have a tremendous impact in horizontal gene transfer in nature, including the spread of antibiotic resistance.

Role of the transmembrane domain in the stability of TrwB, an integral protein involved in bacterial conjugation.

TrwB is an integral membrane protein encoded by the conjugative plasmid R388. TrwB binds ATP and is essential for R388-directed bacterial conjugation. The protein consists of a cytosolic domain, which contains an ATP-binding site, and a transmembrane domain.