Nurse anesthetists have been providing anesthesia care to patients in the United States for more than 150 years. The credential CRNA (Certified Registered Nurse Anesthetist) came into existence in 1956.
E. coli Replication Origin. The E. coli replication origin oriC is an â240-bp DNA segment present at the start site for replication of E. coli chromosomal DNA. Plasmids or any other circular DNA containing oriC are capable of independent and controlled replication in E. coli cells.. coli Replication Origin. The E. coli replication origin oriC is an â240-bp DNA segment present at the start site for replication of E. coli chromosomal DNA. Plasmids or any other circular DNA containing oriC are capable of independent and controlled replication in E. coli cells.
The first model for a DNA synthesis regulatory circuit was described about 50 years ago (Jacob et al. 1963), based on the idea that an early, key step in building new replication forks was the binding of a chromosomally encoded initiator protein to specialized DNA regions, termed replication origins (Fig. 1). The number of replication origins in a genome is, for the most part, dependent on chromosome size. Bacterial and archaeal genomes, which usually consist of a small circular chromosome, frequently have a single replication origin (Barry and Bell 2006; Gao and Zhang 2007).