RecBCD enzyme of Escherichia coli is required for the major pathway of homologous recombination following conjugation. The enzyme has an ATP-dependent DNA unwinding activity, ATP-dependent single-stranded (ss) and double-stranded (ds) DNA exonuclease activities, and an activity that makes a ss DNA endonucleolytic cut near Chi sites. We have isolated and characterized ten mutations that reduced ...

Improving students’ understanding of the nature of experimental physics is often an explicit or implicit goal of undergraduate laboratory physics courses. However, lab activities in traditional lab courses are typically characterized by highly structured, guided labs that often do not require or encourage students to engage authentically in the process of experimental physics. Alternatively, op...

The aim of this study was to examine Iranian EFL university students’ level of anxiety and their perceptions towards in-class activities during speaking courses and possible causes of apprehension. Moreover, this study investigated whether or not EFL university students’ gender differences affect their perceptions of foreign language speaking anxiety. To this end, data were collecte...

Trypanosoma cruzi, the causative agent of Chagas' disease in humans, is an intracellular protozoan parasite with the ability to invade a wide variety of mammalian cells by a unique and remarkable process in cell biology that is poorly understood. Here we present evidence suggesting a role for the host phosphatidylinositol (PI) 3-kinases during T. cruzi invasion. The PI 3-kinase inhibitor wortma...

Alcohol dehydrogenase (ADH) participates in the formation of retinoic acid from retinol in various organs including the gastric mucosa. However, its clinical significance still remains to be clarified. In this study, we identified the ADH isoforms responsible for the retinoic acid formation among various ADH isoforms and examined associations among the ADH activities, the retinoic acid formatio...

Different isoforms of chitinases and [beta]-1,3-glucanases of tobacco (Nicotiana tabacum cv Samsun NN) were tested for their antifungal activities. The class I, vacuolar chitinase and [beta]-1,3-glucanase isoforms were the most active against Fusarium solani germlings, resulting in lysis of the hyphal tips and in growth inhibition. In additon, we observed that the class I chitinase and [beta]-1...

To reuse an electronic educational material, a teacher has to understand its availability and methodology. This paper proposed the technique of integrating electronic class text, such as HTML/XML, into automated records of activities in a class. Our hypothesis is that an activity has influence on both the automated records and the class text. We designed structured record expression and event r...

While the advantages of cooperative learning activities have been extensively acknowledged in L2 literature, this type of pedagogy has not received due attention in the Iranian EFL context. Indeed, the traditional reading method still dominates in most Iranian EFL university classes even though it fails to meet its main objective which is training competent EFL readers. In an attempt to address...