Minimal quota for zinc

Value 200000 Zinc atoms/cell
Organism Bacteria Escherichia coli
Reference Outten CE, O'Halloran TV. Femtomolar sensitivity of metalloregulatory proteins controlling zinc homeostasis. Science. 2001 Jun 29 292(5526):2488-92. p.2488 right column 2nd paragraph and p.2491 middle column top paragraphPubMed ID11397910
Method "21.E. coli strain BW25113 ( 37 ) was grown with shaking at 37°C in LB or Chelex-treated (Bio-Rad) A minimal medium ( 38 ) containing 0.2% glucose and 40 m g/ml of all 20 L -amino acids to an optical density at 600 nm of 0.5 to 0.6. The cells were harvested at midlog growth and washed three times with fresh media containing 1 mM EDTA and one time with Milli-Q water. The pelleted cells were dried overnight at 80°C in Teflon tubes, dissolved in concentrated nitric acid, and the metal content measured by ICP-MS (PQ ExCell, TJA Solutions, Franklin, MA). Parallel control experiments were run to determine the background metal contamination in the materials used. All glassware and plasticware was acid-washed before use. 22. The total cellular concentration of each element was calculated assuming a maximal cellular volume of 1.8 m m 3 for cells grown in minimal medium and 3.5 m m 3 in LB medium ( 23 , 31 ). Metal concentrations in media were determined by inductively coupled plasma atomic emission spectroscopy (Thermo Jarrell Ash AtomScan 25 ICP-AES) for Mg, Ca, and K and ICP-MS for all other elements. Because transition metal concentrations in minimal medium were substantially lower than in LB, ICP-MS measurements of minimal media samples employed the standard addition method. This reduced matrix effects."
Comments "Growth in a metal-depleted medium establishes the minimal quota for this element, or 2?10^5 atoms of zinc per cell [determined here as a colony-forming unit (CFU)] (measurement method) (Fig. 1A)"
Entered by Uri M
ID 108829