title: Use of protoplasts from paired heterogenic bacterial species to detect tin contaminants: prospects for biosensor development.
abstract: Two different bacteria gave different respiratory responses to the test analytes, tributyl tin (TBT) and cadmium as expressed by positive sigmoid responses by Halomonas sp. (slope, +1.71 [TBT]; +1.76 [Cd]) and negative sigmoid responses by Bacillus pumilis (slope, -1.06 [TBT]; -0.59 [Cd]). The EC50 values determined from Hill plots for the response of Halomonas sp. to the TBT and Cd were 1 and 8.5 mM, respectively, which were lower by a factor of 10 than the corresponding values for B. pumilis. With protoplasts of B. pumilis there was a major shift in the signal from sigmoid negative to positive with TBT (+1.35) but not Cd (-0.5), while the signals with the remaining protoplast-analyte combinations remained unchanged. For all four protoplast-analyte combinations the EC50 values were in the order of 10-100-fold lower than those for their whole cell counterparts. When other analytes were tested the protoplasts gave a similar response to tin as for TBT, but detected copper and 2,4-dichlorophenol with similar signal profiles to Cd and with lower sensitivity. The difference in signal and higher sensitivity of the two species protoplast system towards TBT/tin compared to the other analytes tested, suggests that it may feasible to develop this approach for the detection of tin residues.
authors.affiliation: Cawthron Institute, Private Bag 2, Nelson, New Zealand. douglas.mountfort@cawthron.org.nz
authors.forename: Douglas
authors.initials: D
authors.lastname: Mountfort
authors.forename: Olivier
authors.initials: O
authors.lastname: Laczka
authors.forename: Claire
authors.initials: C
authors.lastname: Debarnot
authors.forename: Audrey
authors.initials: A
authors.lastname: Bonnin
authors.forename: Neil
authors.initials: N
authors.lastname: Pasco
authors.forename: Gareth
authors.initials: G
authors.lastname: Lloyd-Jones
mesh_terms: D001407:Bacillus; D015374:Biosensing Techniques; D020632:Halomonas; D011523:Protoplasts; D014001:Tin / Q000032:analysis*
chemical_list: D014001:Tin