In summary, a pattern is becoming apparent in the various mechanisms that regulate expression of genes known or implicated in protection against nitrosative stress. Whatever

the growth conditions and, however, severe the nitrosative stress, groups of proteins are synthesized to protect the bacterial cytoplasm against the side effects of nitrate and nitrite reduction (Fig. 2). We are grateful to Professor www.selleckchem.com/products/PD-0332991.html David Richardson and Dr G. Rowley, University of East Anglia, for allowing us to cite data from their laboratory in advance of publication. “
“Candida albicans is an important human fungal pathogen. Resistance to all major antifungal agents has been observed in clinical isolates of Candida spp. and is a major clinical challenge. The rise and expansion of drug-resistant selleckchem mutants during exposure to antifungal agents occurs through a process of adaptive evolution, with potentially complex population dynamics. Understanding the population dynamics during the emergence of drug resistance is important for determining the fundamental principles of how fungal pathogens evolve for resistance. While few detailed

reports that focus on the population dynamics of C. albicans currently exist, several important features on the population structure and adaptive landscape can be elucidated from existing evolutionary studies in in vivo and in vitro systems. Evolution allows each organism to survive and adapt to changing environments and thus is the driving force behind the biodiversity on earth. The discovery and use of antibiotics is a major advancement in modern medicine. However, the widespread use of antimicrobial agents results in the emergence of drug-resistant strains among previously drug-susceptible

Parvulin populations. These drug-resistant strains arise in the population during the exposure to the antimicrobial agent through a process of adaptive evolution. During adaptive evolution, mutants arise spontaneously, and through a process of natural selection, the adaptive mutant will expand in the population until either it becomes the dominant clone or a fitter clone arises in the population. Depending on the selective pressure, adaptive landscape, frequency of beneficial mutations and population size, the population structure may be complex and consist of multiple-resistant genotypes.