TY - JOUR T1 - “<em>mazEF</em> mediated programmed cell death in Escherichia coli”: is it? JF - bioRxiv DO - 10.1101/048728 SP - 048728 AU - Bhaskar Chandra Mohan Ramisetty AU - Swati Raj AU - Dimpy Ghosh Y1 - 2016/01/01 UR - http://biorxiv.org/content/early/2016/04/14/048728.abstract N2 - Toxin-antitoxins systems (TAS) are prokaryotic operons containing two small overlapping genes which encode two components referred to as Toxin and Antitoxin. Involvement of TAS in bacterial programmed cell death (PCD) is highly controversial. MazEF, a typical type II TAS, is particularly implicated in mediating PCD in Escherichia coli. Hence, we compared the metabolic fitness and stress tolerance of E. coli strains (MC4100 and its mazEF- derivative) which were extensively used by proponents of mazEF- mediated PCD. We found that both the strains are deficient in relA gene and that the ΔmazEF strain has lower fitness and stress tolerance compared to wild type MC4100. Furthermore, these strains are likely not isogenic. We could not reproduce mazEF mediated PCD which emphasizes the need for skeptic approach to the PCD hypothesis. ER -