Exploiting bacterial DNA gyrase as a drug target: current state and perspectives

DNA gyrase is a type II topoisomerase that can introduce negative supercoils into DNA at the expense of ATP hydrolysis. It is essential in all bacteria but absent from higher eukaryotes, making it an attractive target for antibacterials. The fluoroquinolones are examples of very successful gyrase-targeted drugs, but the rise in bacterial resistance to these agents means that we not only need to seek new compounds, but also new modes of inhibition of this enzyme. We review known gyrase-specific drugs and toxins and assess the prospects for developing new antibacterials targeted to this enzyme

Essay Prompts and the ESOL Student

Recent research on writing prompts which fit the preferences of English NS writers has found that NS writers prefer prompts in question form (Brossell & Ash, 1984) and that anticipating a good grade will positively influence writers' choices (Hayward, 1988). Little is known about whether this applies to L2 writers, however. The present study surveyed 142 ESOL students for their preferences as to form of prompt, and also surveyed for other factors relating to their choices such as perceived difficulty of a topic. Each student used a 5-point Likert scale to respond to ten potential prompts. The data were then analyzed using ANOVA, correlation analysis, and multiple regression analysis. No statistically significant difference was found in students' preference for prompts in different forms (question or statement). However, perceived ease, degree of interest, and potential prolificacy of prompt individually and as a group correlated strongly with students' preferences. It seems that ESOL students, while perhaps not alert to potentially helpful syntactic clues in prompts, are nonetheless probably using appropriate strategies when given a choice of prompt to write on

Drug-induced relaxation of supercoiled plasmid DNA in Bacillus subtilis and induction of the SOS response.

Whereas treatment with many different drugs led to induction of the SOS response in Bacillus subtilis, only inhibitors of DNA gyrase subunit B and, unexpectedly, polyether antibiotics (membrane ionophores) led to relaxation of supercoiled plasmid DNA. However, treatment with DNA gyrase subunit B inhibitors but not with polyethers led to SOS induction. Thus, the presence of underwound supercoiled DNA was not sufficient to induce the SOS response. Possible mechanisms by which polyethers induce relaxation of supercoiled DNA in vivo are discussed