Alcaligenes eutrophus CH34 is a facultative chemolithotroph with plasmid-bound resistance to heavy metals

Abstract

Akaligenes eutrophus strain CH34, which was isolated as a bacterium resistant to cobalt, zinc, and cadmium ions, shares with A. eutrophus strain H16 the ability to grow lithoautotrophically on molecular hydrogen, to form a cytoplasmic NAD-reducing and a membrane-bound hydrogenase, and most metabolic attributes; however, it does not grow on fructose. Strain CH34 contains two plasmids, pMOL28 (163 kilobases) specifying nickel, mercury, and cobalt resistance and pMOL30 (238 kilobases) specifying zinc, cadmium, mercury, and cobalt resistance. The plasmids are self-transmissible in homologous matings, but at low frequencies. The transfer frequency was strongly increased with IncPl plasmids RP4 and pUZ8 as helper plasmids. The phenotypes of the wild type, cured strains, and transconjugants are characterized by the following MICs (Micromolar) in strains with the indicated phenotypes: Nic+, 2.5; Nic-, 0.6; Cob+A, 5.0; Cob+B, 20.0; Cob-, < 9.07; Zin+, 12.0; Zin-, 0.6; Cad', 2.5; and Cad-, 0.6. Plasmid-free cells of strain CH34 are still able to grow lithoautotrophicaily and to form both hydrogenases, indicating that the hydrogenase genes are located on the chromosome, in contrast to the Hox structural genes of strain H16, which are located on the megaplasmid pHG1 (450 kilobases).

Paleomicrobiology to investigate copper resistance in bacteria: isolation and description of Cupriavidus necator B9 in the soil of a medieval foundry

“…Plates were then incubated at 258C and examined periodically during one month. Medium 284 contained (final concentrations) Tris 50 mM pH 7.0, NaCl 80 mM, KCl 20 mM, NH 4 Cl 20 mM, Na 2 SO 4 3 mM, MgCl 2 6H 2 O 1 mM, CaCl 2 2H 2 O 0.2 mM, Na 2 HPO 4 2H 2 O 0.004%, Fe(III)NH 4 citrate 0.00048%, gluconate 0.2% and Difco Bac-toAgar 15 g L 21 (Mergeay et al, 1985). One mL of the trace element solution SL7 of Biebl and Pfennig (1981) was also added per liter of medium.…”

“…One mL of the trace element solution SL7 of Biebl and Pfennig (1981) was also added per liter of medium. Medium 284 is a Tris-buffered and low phosphate medium designed to reduce metal complexation and determine accurate minimal inhibitory concentrations (MICs) (Mergeay et al, 1985).…”

Rock geochemistry induces stress and starvation responses in the bacterial proteome

“…Cupriavidus metallidurans was routinely cultured at 30°C in Tris salts minimal medium (MM284) at pH 7 with 0.2% (w/v) sodium gluconate and ferric ammonium citrate as the iron source, as described previously (Mergeay et al, 1985).…”

Species variation and plasmid incidence among fluorescent Pseudomonas strains isolated from agricultural and industrial soils

“…P. putidu PF015 (HgS) and P. putida PF015 (pGTE271 (Hg') were used as controls. Resistance to cadmium, nickel and zinc was determined by comparison of growth of the soil strains to that of a multiple heavy metal-resistant Alcaligenes eutrophus strain CH34 on Tris-gluconate medium supplemented with heavy metal solutions as recommended by Mergeay et al [16]. These heavy metal solutions were applied as 2.5 mM CdCl, .…”