Influence of the Escherichia coli oxyR gene function on λ prophage maintenance

In Escherichia coli hosts, hydrogen peroxide is one of the factors that may cause induction of λ prophage. Here, we demonstrate that H2O2-mediated λ prophage induction is significantly enhanced in the oxyR mutant host. The mRNA levels for cI gene expression were increased in a λ lysogen in the presence of H2O2. On the other hand, stimulation of the pM promoter by cI857 overproduced from a multicopy plasmid was decreased in the ΔoxyR mutant in the presence of H2O2 but not under normal growth conditions. The purified OxyR protein did bind specifically to the pM promoter region. This binding impaired efficiency of interaction of the cI protein with the OR3 site, while stimulating such a binding to OR2 and OR1 sites, in the regulatory region of the pM promoter. We propose that changes in cI gene expression, perhaps in combination with moderately induced SOS response, may be responsible for enhanced λ prophage induction by hydrogen peroxide in the oxyR mutant. Therefore, OxyR seems to be a factor stimulating λ prophage maintenance under conditions of oxidative stress. This proposal is discussed in the light of efficiency of induction of lambdoid prophages bearing genes coding for Shiga toxins

Association of sports and physical activity with obesity among teenagers in Poland

Objectives The purpose of the study was to assess the relationship between the body mass index and sports and physical activities in an unbiased, simple, random sample of teenagers from mid-northeastern Poland. Material and Methods Children and adolescents aged 10–19 years old were surveyed. The Internet-based survey was conducted to collect information on physical activity, leisure time, studying hours, weight, and height. Results Obesity was found to be low in the study population. The overall prevalence of overweight was not higher than 8%. Only 0.6% of participants were underweight. Overall, 68% of them confirmed participating in sports. Boys were frequently more active than girls (> 70% boys and > 60% girls). Participants mostly played soccer, volleyball, handball, or basketball (30.5%); 7% of them practiced martial arts and 16.5% of them participated in swimming. Sports activity significantly influenced body mass index. Obesity was not related to the lack of participation for physical activity in girls but a significant relationship was observed in boys (p < 0.02). The risk of obesity or overweight for inactive teenagers increased 2-fold (p < 0.01). Conclusions We report the overall participation of teenagers from 2 cities in mid-northeastern Poland in sports and physical activities and demonstrate that the lack of statistically significant differences in the body mass index and obesity and overweight is prevalent among boys and girls. Obesity was significantly related to less physical activity in boys, and the likelihood of obesity or overweight increased in inactive teenagers. Thus, we suggest that the importance of overweight and obesity prevention programs should be emphasized. Int J Occup Med Environ Health 2018;31(6):771–78

J. Biol. Chem.

Apart from its function as an initiator of DNA replication, the Escherichia coli DnaA protein is also a specific transcription factor. It activates and represses a number of promoters. However, mechanisms of transcription stimulation by DnaA remained unknown. Bacteriophage pR promoter is one of the promoters activated by DnaA. It was reported previously that DnaA binds downstream of the pR promoter and perhaps interacts with the RNA polymerase subunit. Here we demonstrate that DnaA positively regulates transcription from pR by stimulation of two steps in transcription initiation: RNA polymerase binding to the promoter region and promoter escape. For this transcription activation, two weak DnaA boxes located downstream of pR are necessary and sufficient. Such a mechanism of transcription activation and location of the activator-binding sites relative to the transcription start point are unusual in prokaryotes. Changes in the distance between the transcription start point and the first DnaA box by 5 and 10 bp and alterations in the orientation of these boxes did not abolish the stimulation of transcription by DnaA, but the efficiency of the promoter activation was different for various mutations. It seems plausible that formation of higher order nucleoprotein structures, involving DNA looping, is necessary for effective stimulation of the pR promoter. At high concentrations, DnaA is a repressor of pR rather than an activator. This repression was found to be because of inhibition of RNA polymerase binding to the promoter region

The ICT as a Driving Force in the Field of Archaeological Research

The paper is a contribution to the domain of computer tools for archaeological excavations and research. The present project described in this paper has been undertaken in close co-operation of specialists from two universities including archaeologists and architects from the CAAD unit. The project objective is to assess the suitability of new media offering an alternative to the traditional methods in archaeological practice

Suppression of the Escherichia coli dnaA46 mutation by changes in the activities of the pyruvate-acetate node links DNA replication regulation to central carbon metabolism.

To ensure faithful transmission of genetic material to progeny cells, DNA replication is tightly regulated, mainly at the initiation step. Escherichia coli cells regulate the frequency of initiation according to growth conditions. Results of the classical, as well as the latest studies, suggest that the DNA replication in E. coli starts at a predefined, constant cell volume per chromosome but the mechanisms coordinating DNA replication with cell growth are still not fully understood. Results of recent investigations have revealed a role of metabolic pathway proteins in the control of cell division and a direct link between metabolism and DNA replication has also been suggested both in Bacillus subtilis and E. coli cells. In this work we show that defects in the acetate overflow pathway suppress the temperature-sensitivity of a defective replication initiator-DnaA under acetogenic growth conditions. Transcriptomic and metabolic analyses imply that this suppression is correlated with pyruvate accumulation, resulting from alterations in the pyruvate dehydrogenase (PDH) activity. Consequently, deletion of genes encoding the pyruvate dehydrogenase subunits likewise resulted in suppression of the thermal-sensitive growth of the dnaA46 strain. We propose that the suppressor effect may be directly related to the PDH complex activity, providing a link between an enzyme of the central carbon metabolism and DNA replication