Adhesion of Shewanella oneidensis MR-1 to iron (Oxy)(Hydr)oxides: microcolony formation and isotherm.
The adhesion of dissimilatory metal reducing bacteria (DMRB) to iron (oxy)(hydr)oxides may play an important role in their respiration on ferric iron-containing minerals, but few quantitative surface cell density measurements have been made thus far. We used confocal microscopy to examine the adhesion of a common DMRB species, Shewanella oneidensis MR-1, onto iron (oxy)(hydr)oxide particulate-coated glass slides across a broad range of bulk (i.e., solution phase) cell densities from 10(5) cells/mL to 2 x 10(9) cells/mL. At bulk cell densities less than 1 x 10(7) cells/mL, cells adhered to the slide surface formed an evenly distributed, homogeneous monolayer, while at the bulk cell densities higher than 2 x 10(8) cells/mL the adhered cells formed distinct microcolonies. As a result of this complex adhesion behavior, simple Langmuir or Freundlich adsorption isotherms do not capture the relationship between the surface cell density and the bulk cell density over the entire range of bulk cell densities. Thus a new, two-step isotherm was developed that incorporated both isolated attached cells at low cell densities as well as microcolonies at higher cell densities.
School of Earth and Atmospheric Sciences, and School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Mengni
M
Zhang
Brian R
BR
Ginn
Thomas J
TJ
Dichristina
Andrew G
AG
Stack
D000327:Adsorption; D001422:Bacterial Adhesion / Q000502:physiology*; D002455:Cell Division; D003470:Culture Media; D005290:Ferric Compounds / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005898:Glass; D018613:Microscopy, Confocal; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D020592:Shewanella / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013816:Thermodynamics
D003470:Culture Media; D005290:Ferric Compounds