title: HydrocarbonoclasticAlcanivoraxIsolates Exhibit Different Physiological and Expression Responses ton-dodecane.
abstract: Autochthonous microorganisms inhabiting hydrocarbon polluted marine environments play a fundamental role in natural attenuation and constitute promising resources for bioremediation approaches.Alcanivoraxspp. members are ubiquitous in contaminated surface waters and are the first to flourish on a wide range of alkanes after an oil-spill. Following oil contamination, a transient community of differentAlcanivoraxspp. develop, but whether they use a similar physiological, cellular and transcriptomic response to hydrocarbon substrates is unknown. In order to identify which cellular mechanisms are implicated in alkane degradation, we investigated the response of two isolates belonging to differentAlcanivoraxspecies,A. dieseloleiKS 293 andA. borkumensisSK2 growing onn-dodecane (C12) or on pyruvate. Both strains were equally able to grow on C12 but they activated different strategies to exploit it as carbon and energy source. The membrane morphology and hydrophobicity of SK2 changed remarkably, from neat and hydrophilic on pyruvate to indented and hydrophobic on C12, while no changes were observed in KS 293. In addition, SK2 accumulated a massive amount of intracellular grains when growing on pyruvate, which might constitute a carbon reservoir. Furthermore, SK2 significantly decreased medium surface tension with respect to KS 293 when growing on C12, as a putative result of higher production of biosurfactants. The transcriptomic responses of the two isolates were also highly different. KS 293 changes were relatively balanced when growing on C12 with respect to pyruvate, giving almost the same amount of upregulated (28%), downregulated (37%) and equally regulated (36%) genes, while SK2 transcription was upregulated for most of the genes (81%) when growing on pyruvate when compared to C12. While both strains, having similar genomic background in genes related to hydrocarbon metabolism, retained the same capability to grow on C12, they nevertheless presented very different physiological, cellular and transcriptomic landscapes.
authors.affiliation: Centre for Microbial Ecology and Technology, Ghent UniversityGhent, Belgium; Department of Food, Environmental and Nutritional Sciences, University of MilanMilan, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Barbato
authors.affiliation: Centre for Microbial Ecology and Technology, Ghent University Ghent, Belgium.
authors.forename: Alberto
authors.initials: A
authors.lastname: Scoma
authors.affiliation: Department of Food, Environmental and Nutritional Sciences, University of Milan Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Mapelli
authors.affiliation: Department of Medical and Forensic Pathology, University of Ghent Ghent, Belgium.
authors.forename: Rebecca
authors.initials: R
authors.lastname: De Smet
authors.affiliation: School of Biomedical Sciences, University of Ulster Coleraine, UK.
authors.forename: Ibrahim M
authors.initials: IM
authors.lastname: Banat
authors.affiliation: Department of Food, Environmental and Nutritional Sciences, University of MilanMilan, Italy; Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and TechnologyThuwal, Saudi Arabia.
authors.forename: Daniele
authors.initials: D
authors.lastname: Daffonchio
authors.affiliation: Centre for Microbial Ecology and Technology, Ghent University Ghent, Belgium.
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.affiliation: Department of Food, Environmental and Nutritional Sciences, University of Milan Milan, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Borin
keywords: Alcanivorax; alkanes; bioremediation; functional redundancy; transcriptomics