DnrN protein activates dnrI, which in turn activates other pathway genes and DNR production commences (Furuya & Hutchinson, 1996; Tang et al., 1996). However, DnrO binding to its OP1 operator sequence results in autorepression (Fig. 6b). When DNR production steadily increases to reach a threshold level, it rate-limits the binding of DnrO to the promoter/operator sequence (Fig. 6c). Our in vitro experiments suggested that 2 ng of DNR 5FU can dislodge 30 ng of DnrO from 10 ng of 511-bp DNA. We conclude that the system is highly sensitive

to DNR accumulation in the cell, which effectively deals with activation/repression functions of regulatory genes. DnrO binding to its DNA sequence is in a continuous state of flux determined by DNR in the cell, and the DNR level is determined

by synthesis and efflux. This process modulates expression of dnrN and dnrI to ensure an equilibrium level of production that is matched by the rate of efflux. We propose that the stoichiometric ratio of DnrO and DNR inside the cell is one of the factors regulating antibiotic biosynthesis by a negative feedback loop. The authors thank the Department of Biotechnology, Government of India, for financial support. Additional funds from UPE project of Madurai Kamaraj University (MKU), India supported by University Grants Commission, India is acknowledged. The authors thank Prof. K. Dharmalingam for his critical comments and technical support. Instrument support given by the Bortezomib molecular weight DBT Centre for Genetic Engineering and Strain Manipulation, at MKU and School of Biotechnology, MKU confocal microscope facility is acknowledged. The authors thank Dr R. Usha and Dr H. Shakila for their help in confocal image acquisition. “
“In the paper through by Rettedal et al. (2010), the

replicate data to show that the same samples amplified with the same set of primers were more similar than samples amplified by different sets of primers was omitted. The data are shown in Fig. 1. “
“Factors underlying individual vulnerability to develop alcoholism are largely unknown. In humans, the risk for alcoholism is associated with elevated cue reactivity. Recent evidence suggests that in animal models, reactivity to reward-paired cues is predictive of addictive behaviors. To model cue reactivity in mice, we used a Pavlovian approach (PA) paradigm in which mice were trained to associate a cue with delivery of a food reinforcer. We then investigated the relationship between PA status with habitual and compulsive-like ethanol seeking. After training mice to respond for 10% ethanol, habitual behavior was investigated using both an outcome devaluation paradigm, in which ethanol was devalued via association with lithium chloride-induced malaise, and a contingency degradation paradigm in which the relationship between action and outcome was disrupted.