TY - JOUR
T1 - Mercury affects the distribution of culturable species of Pseudomonas in soil
AU - Holtze, M.S.
AU - Nielsen, P.
AU - Ekelund, Flemming
AU - Rasmussen, L.D.
AU - Johnsen, Kaare Eske
N1 - Keywords: 16S rDNA partial sequencing; FT-IR; Mercury; Pseudomonas; Resistance
PY - 2006
Y1 - 2006
N2 - Pseudomonas bacteria isolated during 52 days on Gould's S1 agar from soil spiked with 0, 3.5 and 15 mg Hg(II) kg soil-1 were characterised to reveal whether mercury affected them differently. Isolates from the treatments with 0 and 15 mg Hg kg-1 were characterised using FT-IR characterisation and subsequent 16S rDNA partial sequencing of representative isolates. To verify the selectivity of Gould's S1 agar and the FT-IR characterisation, all 450 isolates were subjected to the following tests: Gram-determination, catalase and oxidase activity, pigment production on PDA and growth at different temperatures. Furthermore, the isolates were tested for their ability to grow on agar amended with 10 mg Hg kg-1 as an indication of mercury resistance. We found that up to 80% of the isolates in soil amended with 15 mg Hg kg-1 were mercury-resistant, whereas only up to 20% were resistant in the treatments with 0 and 3.5 mg Hg kg-1. We found two groups of Pseudomonas, which probably represent non-described species since they did not group closely with any known species of Pseudomonas in the dendrogram. Hg-enhanced isolates were closely related to P. frederiksbergensis. Furthermore, Hg resistance was almost exclusively restricted to P. frederiksbergensis and P. migulae groups. We conclude that Hg caused a shift in the dominating species of culturable Pseudomonas.
AB - Pseudomonas bacteria isolated during 52 days on Gould's S1 agar from soil spiked with 0, 3.5 and 15 mg Hg(II) kg soil-1 were characterised to reveal whether mercury affected them differently. Isolates from the treatments with 0 and 15 mg Hg kg-1 were characterised using FT-IR characterisation and subsequent 16S rDNA partial sequencing of representative isolates. To verify the selectivity of Gould's S1 agar and the FT-IR characterisation, all 450 isolates were subjected to the following tests: Gram-determination, catalase and oxidase activity, pigment production on PDA and growth at different temperatures. Furthermore, the isolates were tested for their ability to grow on agar amended with 10 mg Hg kg-1 as an indication of mercury resistance. We found that up to 80% of the isolates in soil amended with 15 mg Hg kg-1 were mercury-resistant, whereas only up to 20% were resistant in the treatments with 0 and 3.5 mg Hg kg-1. We found two groups of Pseudomonas, which probably represent non-described species since they did not group closely with any known species of Pseudomonas in the dendrogram. Hg-enhanced isolates were closely related to P. frederiksbergensis. Furthermore, Hg resistance was almost exclusively restricted to P. frederiksbergensis and P. migulae groups. We conclude that Hg caused a shift in the dominating species of culturable Pseudomonas.
U2 - 10.1016/j.apsoil.2005.05.004
DO - 10.1016/j.apsoil.2005.05.004
M3 - Journal article
SN - 0929-1393
VL - 31
SP - 228
EP - 238
JO - Agriculture, Ecosystems & Environment. Applied Soil Ecology
JF - Agriculture, Ecosystems & Environment. Applied Soil Ecology
IS - 3
ER -