In other bacterial species, there are now several examples of DnaA-regulated genes whose expression was shown to depend on both the concentration and the nucleotide-bound state of DnaA , but the role of the nucleotide bound to DnaA in the regulation of the activity of DnaA as a transcription factor still remains poorly understood in most cases . Thus, the full extend to which DnaA is utilized to regulate the timing of gene expression during the bacterial cell cycle is an interesting avenue for future research and C. crescentus is an ideal model to study such questions. Rifampicin-treated cells were fixed and stained with the DNAbinding Vybrant DyeCycle Orange , as previously described . Rifampicin treatment of cells blocks the initiation of chromosomal replication, but allows ongoing rounds of replication to finish. Fixed cells were analyzed using a FACSCalibur cytometer, equipped with an air-cooled argon laser . Flow cytometry data were acquired using the CellQuest software. 30000 cells were analyzed from each biological sample. To quantify the AP24534 results , the proportion of cells having 1N, 2N or .2N chromosomes was estimated on the basis of the fluorescence area given by the flow cytometer for each cell. The data were normalized so that the fluorescence value for the maximum of the 1N peak is equal for all data sets. The average difference N between the 2N and the 1N peak maximum was estimated from representative data sets. In each data set, all cells whose fluorescence is greater than 0.5N and smaller than 1.5N fall in the 1N category; all cells whose fluorescence is greater than 1.5N and smaller than 2.5N fall in the 2N category; all cells whose fluorescence is greater that 2.5N fall in the .2N category. The autism spectrum disorders are a group of neurodevelopmental diseases caused by multiple genetic and environmental factors . Despite the immense etiological heterogeneity in ASDs, affected individuals have common behavioral manifestations that may arise due to perturbation of common neurodevelopmental processes. In the long term, identification of common cell- and molecular-level elements underlying the ASDs will require a broad study of both idiopathic and genetically correlated cases. One of the major TWS119 supplier obstacles to identification of therapeutic interventions for the ASDs has been the difficulty of studying the step-by-step development of the disease in systems that are amenable to drug and functional genomic screening. Recent advances in stem cell biology and the advent of somatic cell reprogramming technology now enable the generation of patientspecific induced pluripotent stem cells that can be differentiated in vitro into a variety of cell types of the nervous system.