@article{Arif_Howard_Tisa_2016, title={Calcium Homeostasis in Escherichia coli: Characterization of Mutants and Genome Expression of MG1655}, volume={31}, url={https://www.banglajol.info/index.php/BJM/article/view/28457}, DOI={10.3329/bjm.v31i1.28457}, abstractNote={<p>While the role of calcium ions as secondary messengers has been well described in eukaryotic cells, little is known about calcium homeostasis in bacteria at the physiological and molecular levels. Genetic and genomic approaches were used to address calcium regulation and to identify genes (<em>cal</em>) involved in calcium homeostasis. Transposon mutagenesis of <em>Escherichia coli </em>generated several calcium-sensitive mutants that fell into three categories: (i) Ca<sup>2+</sup>-sensitive chemotaxis mutants, (ii) Ca<sup>2+</sup>-sensitive cell division mutants, and (iii) Ca<sup>2+</sup>-sensitive mutants that showed no defects in cell division or chemotaxis. The physiological properties of these Ca<sup>2+</sup>-sensitive mutants were determined. Besides calcium-sensitivity to 75 m<em>M </em>calcium, all of the mutants exhibited increased sensitivities to several divalent cations including Ni<sup>2+</sup>, Mg<sup>2+</sup>, Mn<sup>2+</sup>, Co<sup>2+</sup>, Zn<sup>2+</sup>, Cu<sup>2+</sup>, and Cd<sup>2+</sup>. To identify the <em>cal </em>gene sequence in the Ca<sup>2+</sup>-sensitive mutants, the region of the genes fused to the reporter gene (<em>phoA</em>) on the transposon Tn<em>phoA </em>was amplified by PCR and sequenced. The sites of the gene fusion for three <em>cal </em>mutants were at the <em>fdoG</em>, <em>gpt </em>and <em>pqi5 </em>genes. The pleiotropic nature for the <em>cal </em>mutations suggested that many genes may be globally regulated by calcium. We then investigated global gene expression patterns of wild-type <em>E. coli </em>under calcium-depleted (addition of 10 m<em>M </em>EGTA) and calcium-elevated (addition of 75 m<em>M </em>Ca<sup>2+</sup>) conditions as compared to cultures grown under unstressed conditions. A comprehensive transcriptome analysis using macroarrys exhibited a global regulation of diverse genes within the <em>E. coli </em>genome during calcium homeostasis.</p><p>Bangladesh J Microbiol, Volume 31, Number 1-2,June-Dec 2014, pp 1-8</p>}, number={1}, journal={Bangladesh Journal of Microbiology}, author={Arif, Muhammad and Howard, Josh and Tisa, Louis S}, year={2016}, month={Jun.}, pages={1–8} }