Mechanisms of fluoroquinolone and macrolide resistance in Campylobacter spp.

The incidence of human Campylobacter infections is increasing worldwide, as well as the proportion of isolates resistant to fluoroquinolones and/or macrolides, the drugs of choice to treat campylobacteriosis. In this review, we report recent developments in the understanding of the resistance mechanisms to fluoroquinolones and macrolides. In addition, we will discuss the recent findings on multidrug resistance in Campylobacter spp.

Burridge-Knopoff model: Exploration of dynamic phases.

Slider-block models are often used to simulate earthquake dynamics. However, the models' origins are more conceptual than analytical. This study uses Navier's equations of an elastic bulk to derive a one-dimensional slider-block model, the Burridge-Knopoff model.

Phenotypic and genotypic anti-microbial resistance profiles of campylobacters from untreated feedlot cattle and their environment.

Anti-microbial resistance is an emerging public health issue. Farmed animals may act as reservoirs and potential sources of anti-microbial resistant Campylobacters. The aim of this study was to investigate the anti-microbial resistance profile of cattle and environmental Campylobacter isolates from normal untreated feedlot cattle, the role of the gyrA Thr-86-Ile mutation in ciprofloxacin-resistant Campylobacter jejuni isolates and the involvement of the tripartite CmeABC efflux system for multi-resistant C.

Suppressed expression of genes involved in transcription and translation in in vitro compared with in vivo cultured bovine embryos.

In vivo-derived bovine embryos are of higher quality than those derived in vitro. Many of the differences in quality can be related to culture environment-induced changes in mRNA abundance. The aim of this study was to identify a range of mRNA transcripts that are differentially expressed between bovine blastocysts derived from in vitro versus in vivo culture.

Deregulation of common genes by c-Myc and its direct target, MT-MC1.

In addition to its role in cancer, the c-Myc oncoprotein controls many normal cellular processes as a consequence of its function as a basic helix-loop-helix leucine zipper transcription factor. Determining which of the myriad genes under c-Myc control are relevant for these various roles is thus a major challenge. mt-mc1 is a direct c-Myc target gene whose overexpression recapitulates multiple c-Myc phenotypes, including transformation.

Characterization of a cmeABC operon in a quinolone-resistant Campylobacter coli isolate of Irish origin.

In this study, a tripartite-operon-encoding efflux system together with its regulatory gene was characterized in an Irish Campylobacter coli isolate CIT-382 showing high-level resistance to nalidixic acid and ciprofloxacin. Sequence comparisons revealed significant homology between C. coli and the cmeABC operon of Campylobacter jejuni.

An investigation of the molecular mechanisms contributing to high-level erythromycin resistance in Campylobacter.

The molecular mechanisms contributing to high-level erythromycin resistance in Campylobacter jejuni and Campylobacter coli isolates were investigated. The A2075G mutation in the 23S rRNA target genes was identified in all high-level erythromycin-resistant isolates. A number of amino acid substitutions together with insertions and deletions were identified in the corresponding genes encoding L4 and L22 ribosomal proteins both of resistant and susceptible isolates.

Effect of culture environment on gene expression and developmental characteristics in IVF-derived embryos.

It is generally accepted that mammalian preimplantation embryos are sensitive to their environment and that conditions of culture can affect future growth and developmental potential both pre- and postnatally. Evidence suggests that while culture conditions during bovine in vitro embryo production can impact somewhat on the developmental potential of the early embryo, the intrinsic quality of the oocyte is the key factor determining the proportion of oocytes developing to the blastocyst stage. In addition, evidence suggests that the period of post fertilization embryo culture is the most critical period affecting blastocyst quality assessed in terms of cryotolerance, gene expression pattern and ability to establish a pregnancy.

Relative contribution of target gene mutation and efflux to varying quinolone resistance in Irish Campylobacter isolates.

The contribution of target gene mutations and active efflux to varying levels of quinolone resistance in Irish Campylobacter isolates was studied. The Thr-86-Ile modification of GyrA did not correlate with the level of quinolone resistance. The efflux pump inhibitor Phe-Arg-beta-Naphthylamide (PAbetaN) had no effect on the MICs to ciprofloxacin.

Predicting embryo quality: mRNA expression and the preimplantation embryo.

To overcome the low implantation rate (10-20%) following IVF in humans, more than two embryos are commonly replaced, potentially leading to high order multiple pregnancies with associated significantly elevated risks. Selecting the most viable embryos and transferring fewer of them could reduce this risk. Prolonged culture of embryos in vitro to the blastocyst stage may expose the embryo to hazards not normally encountered in the female reproductive tract.

Problem-based, peer-facilitated education about antibiotic prescribing.

Aims: To assess the feasibility and acceptability of a problem-based, peer-facilitated educational workshop about antibiotic prescribingfor GPs.

Participants: All 39 GPs working in an average sized Local Health Care Co-operative (LHCC) in Glasgow.

Intervention: Prospective collection of information about 10 prescriptions for antibiotics to assess learning needs in relation to antibiotic prescribing.

Workload and short-term outcome of babies weighing 2,500 grams or more at birth admitted to the paediatric unit of the Rotunda Hospital.

Background: Audit is important in ensuring adequate use of resources and maintaining optimum standards of care. Most of the emphasis in neonatal audit is focused on very low birth weight infants. However, term and near-term infants account for a significant proportion of the workload in neonatal units and warrant regular audit.

FOOTER: a web tool for finding mammalian DNA regulatory regions using phylogenetic footprinting.

FOOTER is a newly developed algorithm that analyzes homologous mammalian promoter sequences in order to identify transcriptional DNA regulatory 'signals'. FOOTER uses prior knowledge about the binding site preferences of the transcription factors (TFs) in the form of position-specific scoring matrices (PSSMs). The PSSM models are generated from known mammalian binding sites from the TRANSFAC database.

enoLOGOS: a versatile web tool for energy normalized sequence logos.

enoLOGOS is a web-based tool that generates sequence logos from various input sources. Sequence logos have become a popular way to graphically represent DNA and amino acid sequence patterns from a set of aligned sequences. Each position of the alignment is represented by a column of stacked symbols with its total height reflecting the information content in this position.

Footer: a quantitative comparative genomics method for efficient recognition of cis-regulatory elements.

The search for mammalian DNA regulatory regions poses a challenging problem in computational biology. The short length of the DNA patterns compared with the size of the promoter regions and the degeneracy of the patterns makes their identification difficult. One way to overcome this problem is to use evolutionary information to reduce the number of false-positive predictions.

Criticality in the Burridge-Knopoff model.

Criticality is a potential origin of the scale invariance observed in the Gutenberg-Richter law for earthquakes. In support of this hypothesis, the Burridge-Knopoff (BK) model of an earthquake fault system is known to exhibit a dynamic phase transition, but the critical nature of the transition is uncertain. Here it is shown that the BK model exhibits a dynamic transition from large-scale stick-slip to small-scale creep motion and through a finite size scaling analysis the critical nature of this transition is established.

Campylobacter.

Species within the genus, Campylobacter, have emerged over the last three decades as significant clinical pathogens, particularly of human public health concern, where the majority of acute bacterial enteritis in the Western world is due to these organisms. Of particular concern are the species, C. jejuni and C.

Secondary nucleation of the beta-polymorph of L-glutamic acid on the surface of alpha-form crystals.

Evidence is presented for the secondary nucleation of beta-L-glutamic acid on the surface of the alpha-polymorph, using a combination of Scanning Electron Microscopy and Raman spectroscopy.

Basin of attraction of a bounded self-organized critical state.

The robustness of the self-organized critical (SOC) state observed in the motion of an annular plate rotating over a granular medium is studied in this paper. In particular, we investigate the effect of parameters to which the emergent SOC state may be sensitive, including the initialization scheme, driving velocity, and confining pressure. The results indicate that the critical state is not a universal attractor, but has a finite basin of attraction.

Insulin-like growth factor receptor levels are regulated by cell density and by long term estrogen deprivation in MCF7 human breast cancer cells.

This work describes a reciprocal relationship between cell density and levels of insulin-like growth factor receptors (IGFR) in MCF7 human breast cancer cells, which adds a new dimension to the mechanism of cross-talk between estrogen and insulin-like growth factors in the regulation of breast cancer cell growth. The reduced binding of both (125)I-IGF1 and alphaIR3 anti-IGFR antibody to whole cells showed that IGFR are lost from the surface of MCF7 cells as cell density increases, and this occurred irrespective of the presence or absence of estradiol. Western immunoblotting further confirmed loss of type I IGFR from MCF7 cells with increasing cell density.