Characterizing RecA-Independent Induction of Shiga toxin2-Encoding Phages by EDTA Treatment

Background: The bacteriophage life cycle has an important role in Shiga toxin (Stx) expression. The induction of Shiga toxin-encoding phages (Stx phages) increases toxin production as a result of replication of the phage genome, and phage lysis of the host cell also provides a means of Stx toxin to exit the cell. Previous studies suggested that prophage induction might also occur in the absence of SOS response, independently of RecA. Methodology/Principal Findings: The influence of EDTA on RecA-independent Stx2 phage induction was assessed, in laboratory lysogens and in EHEC strains carrying Stx2 phages in their genome, by Real-Time PCR. RecA-independent mechanisms described for phage l induction (RcsA and DsrA) were not involved in Stx2 phage induction. In addition, mutations in the pathway for the stress response of the bacterial envelope to EDTA did not contribute to Stx2 phage induction. The effect of EDTA on Stx phage induction is due to its chelating properties, which was also confirmed by the use of citrate, another chelating agent. Our results indicate that EDTA affects Stx2 phage induction by disruption of the bacterial outer membrane due to chelation of Mg 2+. In all the conditions evaluated, the pH value had a decisive role in Stx2 phage induction. Conclusions/Significance: Chelating agents, such as EDTA and citrate, induce Stx phages, which raises concerns due to their frequent use in food and pharmaceutical products. This study contributes to our understanding of the phenomenon o

Worldwide acceleration of mountain erosion under a cooling climate

Climate influences the erosion processes acting at the Earth’s surface. However, the effect of cooling during the Late Cenozoic era, including the onset of Pliocene–Pleistocene Northern Hemisphere glaciation (about two to three million years ago), on global erosion rates remains unclear1, 2, 3, 4. The uncertainty arises mainly from a lack of consensus on the use of the sedimentary record as a proxy for erosion3, 4 and the difficulty of isolating the respective contributions of tectonics and climate to erosion5, 6, 7. Here we compile 18,000 bedrock thermochronometric ages from around the world and use a formal inversion procedure8 to estimate temporal and spatial variations in erosion rates. This allows for the quantification of erosion for the source areas that ultimately produce the sediment record on a timescale of millions of years. We find that mountain erosion rates have increased since about six million years ago and most rapidly since two million years ago. The increase of erosion rates is observed at all latitudes, but is most pronounced in glaciated mountain ranges, indicating that glacial processes played an important part. Because mountains represent a considerable fraction of the global production of sediments9, our results imply an increase in sediment flux at a global scale that coincides closely with enhanced cooling during the Pliocene and Pleistocene epochs10, 11

Dieting and overeating

Item does not contain fulltextPurpose: After a calorie-restricted diet, most people regain most of their lost body weight. The present chapter focuses on two possible psychological explanations for this weight regain (1) as caused by possible side effects of dieting, specifically the disinhibition effect (the overeating by dieters after they abandoned their dietary restraint), and (2) as caused by the fact that most treatments do not address possible causes of emotional eating (EE). Findings: The disinhibition effect, though a robust phenomenon when dietary restraint was measured with the Restraint Scale, could not be replicated with other measures for restraint. This generated a discussion i) how restraint should best be measured and conceptualized and (ii) whether the disinhibition effect holds true for all dieters or whether it is only found in a subgroup of dieters, the so-called unsuccessful dieters. Unsuccessful dieters combine high dietary restraint with high overeating tendencies. It is further noted that the disinhibitor "ego threat" elicits EE. However, disinhibition requires prior inhibition (i.e., restraint) by definition. Because restrained eating may be both cause and consequence of EE, also evidence on possible causes of EE (independent from dieting) is presented, in addition to evidence on EE as marker of atypical depression (the subtype of depression associated with increased appetite and weight gain). Implications for treatment: Side effects of dieting and associations of EE with alexithymia (difficulty in identifying and describing emotions) and atypical depression suggest that treatment of obesity should not automatically consist of prescribing calorie-restricted diets. Instead treatments should match with an individual’s eating style. The DEBQ (Dutch Eating Behavior Questionnaire) enables such matched treatment of obesity

Legislation on direct-to-consumer genetic testing in seven European countries

An increasing number of private companies are now offering direct-to-consumer (DTC) genetic testing services. Although a lot of attention has been devoted to the regulatory framework of DTC genetic testing services in the USA, only limited information about the regulatory framework in Europe is available. We will report on the situation with regard to the national legislation on DTC genetic testing in seven European countries (Belgium, the Netherlands, Switzerland, Portugal, France, Germany, the United Kingdom). The paper will address whether these countries have legislation that specifically address the issue of DTC genetic testing or have relevant laws that is pertinent to the regulatory control of these services in their countries. The findings show that France, Germany, Portugal and Switzerland have specific legislation that defines that genetic tests can only be carried out by a medical doctor after the provision of sufficient information concerning the nature, meaning and consequences of the genetic test and after the consent of the person concerned. In the Netherlands, some DTC genetic tests could fall under legislation that provides the Minister the right to refuse to provide a license to operate if a test is scientifically unsound, not in accordance with the professional medical practice standards or if the expected benefit is not in balance with the (potential) health risks. Belgium and the United Kingdom allow the provision of DTC genetic tests