title: The Pseudomonas community in metal-contaminated sediments as revealed by quantitative PCR: a link with metal bioavailability.
abstract: Pseudomonas bacteria are ubiquitous Gram-negative and aerobic microorganisms that are known to harbor metal resistance mechanisms such as efflux pumps and intracellular redox enzymes. Specific Pseudomonas bacteria have been quantified in some metal-contaminated environments, but the entire Pseudomonas population has been poorly investigated under these conditions, and the link with metal bioavailability was not previously examined. In the present study, quantitative PCR and cell cultivation were used to monitor and characterize the Pseudomonas population at 4 different sediment sites contaminated with various levels of metals. At the same time, total metals and metal bioavailability (as estimated using an HCl 1 m extraction) were measured. It was found that the total level of Pseudomonas, as determined by qPCR using two different genes (oprI and the 16S rRNA gene), was positively and significantly correlated with total and HCl-extractable Cu, Co, Ni, Pb and Zn, with high correlation coefficients (>0.8). Metal-contaminated sediments featured isolates of the Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas lutea and Pseudomonas aeruginosa groups, with other bacterial genera such as Mycobacterium, Klebsiella and Methylobacterium. It is concluded that Pseudomonas bacteria do proliferate in metal-contaminated sediments, but are still part of a complex community.
authors.affiliation: Proteomics and Microbiology Lab, Research Institute for Biosciences, Université de Mons, 20 Place du Parc, B-7000 Mons, Belgium. Electronic address: stephanie.roosa@umons.ac.be.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Roosa
authors.affiliation: Institut de Recherches Microbiologiques JMW, 1 Av. E. Gryzon, 1070 Bruxelles, Belgium. Electronic address: cvdwauve@ulb.ac.be.
authors.forename: Corinne Vander
authors.initials: CV
authors.lastname: Wauven
authors.affiliation: Géosystèmes Lab, UFR de Chimie, Lille-1 University, Sciences and Technologies, 59655 Villeneuve d'Ascq, France. Electronic address: gabriel.billon@univ-lille1.fr.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Billon
authors.affiliation: Institut de Recherches Microbiologiques JMW, 1 Av. E. Gryzon, 1070 Bruxelles, Belgium. Electronic address: slmatthi@ulb.ac.be.
authors.forename: Sandra
authors.initials: S
authors.lastname: Matthijs
authors.affiliation: Proteomics and Microbiology Lab, Research Institute for Biosciences, Université de Mons, 20 Place du Parc, B-7000 Mons, Belgium. Electronic address: ruddy.wattiez@umons.ac.be.
authors.forename: Ruddy
authors.initials: R
authors.lastname: Wattiez
authors.affiliation: Proteomics and Microbiology Lab, Research Institute for Biosciences, Université de Mons, 20 Place du Parc, B-7000 Mons, Belgium. Electronic address: david.gillan@umons.ac.be.
authors.forename: David C
authors.initials: DC
authors.lastname: Gillan
mesh_terms: D001682:Biological Availability; D058448:Biota; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology*; D008670:Metals / Q000378:metabolism*; D008969:Molecular Sequence Data; D011549:Pseudomonas / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D008670:Metals; D012336:RNA, Ribosomal, 16S
keywords: Bioavailability; Metals; Pseudomonas; Quantitative PCR; Resistance; Sediments