New insights on the reorganization of gene transcription in Pseudomonas putida KT2440 at elevated pressure

Follonier, Stéphanie (School of Engineering, HES-SO Valais-Wallis, HEI, HES-SO // University of Applied Sciences Western Switzerland ; Empa Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland) ; Escapa, Isabel F. (Environmental Biology Department, Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain) ; Fonseca, Pilar M (Environmental Biology Department, Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain) ; Henes, Bernhard (Empa Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland) ; Panke, Sven (ETH Zurich, Basel, Switzerland) ; Zinn, Manfred (Empa Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland) ; Zinn, Manfred (Empa Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland ; School of Engineering, HES-SO Valais-Wallis, HEI, HES-SO // University of Applied Sciences Western Switzerland) ; Prieto, Maria Auxiliadora (Environmental Biology Department, Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain)

Background : Elevated pressure, elevated oxygen tension (DOT) and elevated carbon dioxide tension (DCT) are readily encountered at the bottom of large industrial bioreactors and during bioprocesses where pressure is applied for enhancing the oxygen transfer. Yet information about their effect on bacteria and on the gene expression thereof is scarce. To shed light on the cellular functions affected by these specific environmental conditions, the transcriptome of Pseudomonas putida KT2440, a bacterium of great relevance for the production of medium-chain-length polyhydroxyalkanoates, was thoroughly investigated using DNA microarrays. Results : Very well defined chemostat cultivations were carried out with P. putida to produce high quality RNA samples and ensure that differential gene expression was caused exclusively by changes of pressure, DOT and/or DCT. Cellular stress was detected at 7 bar and elevated DCT in the form of heat shock and oxidative stress-like responses, and indicators of cell envelope perturbations were identified as well. Globally, gene transcription was not considerably altered when DOT was increased from 40 ± 5 to 235 ± 20% at 7 bar and elevated DCT. Nevertheless, differential transcription was observed for a few genes linked to iron-sulfur cluster assembly, terminal oxidases, glutamate metabolism and arginine deiminase pathway, which shows their particular sensitivity to variations of DOT. Conclusions : This study provides a comprehensive overview on the changes occurring in the transcriptome of P. putida upon mild variations of pressure, DOT and DCT. Interestingly, whereas the changes of gene transcription were widespread, the cell physiology was hardly affected, which illustrates how efficient reorganization of the gene transcription is for dealing with environmental changes that may otherwise be harmful. Several particularly sensitive cellular functions were identified, which will certainly contribute to the understanding of the mechanisms involved in stress sensing/response and to finding ways of enhancing the stress tolerance of microorganisms.


Keywords:
Article Type:
scientifique
Faculty:
Ingénierie et Architecture
School:
HEI-VS
Institute:
Institut Technologies du vivant
Date:
2013-03
Pagination:
18 p.
Published in:
Microbial Cell Factories
Numeration (vol. no.):
2013, vol. 12, article no. 30
DOI:
ISSN:
1475-2859
Appears in Collection:



 Record created 2021-07-02, last modified 2021-07-06

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