Biophysical properties of membrane lipids of anammox bacteria: II. Impact of temperature and bacteriohopanoids.
Anammox bacteria possess unique membranes that are mainly comprised of phospholipids with extraordinary "ladderane" hydrocarbon chains containing 3 to 5 linearly concatenated cyclobutane moieties that have been postulated to form relatively impermeable membranes. In a previous study, we demonstrated that purified ladderane phospholipids form fluid-like mono- and bilayers that are tightly packed and relatively rigid. Here we studied the impact of temperature and the presence of bacteriohopanoids on the lipid density and acyl chain ordering in anammox membranes using Langmuir monolayer and fluorescence depolarization experiments on total lipid extracts. We showed that anammox membrane lipids of representatives of Candidatus "Kuenenia stuttgartiensis", Candidatus "Brocadia fulgida" and Candidatus "Scalindua" were closely packed and formed membranes with a relatively high acyl chain ordering at the temperatures at which the cells were grown. Our findings suggest that bacteriohopanoids might play a role in maintaining the membrane fluidity in anammox cells.
Department of Marine Organic Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB, Den Burg, Texel, The Netherlands.
Henry A
HA
Boumann
Pieter
P
Stroeve
Marjorie L
ML
Longo
Bert
B
Poolman
Johanna M
JM
Kuiper
Ellen C
EC
Hopmans
Mike S M
MS
Jetten
Jaap S
JS
Sinninghe Damsté
Stefan
S
Schouten
D001419:Bacteria / Q000737:chemistry* / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry*; D005453:Fluorescence; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D013696:Temperature
D008563:Membrane Lipids; D010743:Phospholipids; D000644:Quaternary Ammonium Compounds