Identification of genes essential for anaerobic growth of Listeria monocytogenes.
The facultative anaerobic bacterium Listeria monocytogenes encounters microaerophilic or anaerobic conditions in various environments, e.g. in soil, in decaying plant material, in food products and in the host gut. To elucidate the adaptation of Listeria monocytogenes to variations in oxygen tension, global transcription analyses using DNA microarrays were performed. In total, 139 genes were found to be transcribed differently during aerobic and anaerobic growth; 111 genes were downregulated and 28 genes were upregulated anaerobically. The oxygen-dependent transcription of central metabolic genes is in agreement with results from earlier physiological studies. Of those genes more strongly expressed under lower oxygen tension, 20 were knocked out individually. Growth analysis of these knock out mutants did not indicate an essential function for the respective genes during anaerobiosis. However, even if not essential, transcriptional induction of several genes might optimize the bacterial fitness of Listeria monocytogenes in anaerobic niches, e.g. during colonization of the gut. For example, expression of the anaerobically upregulated gene lmo0355, encoding a fumarate reductase α chain, supported growth on 10 mM fumarate under anaerobic but not under aerobic growth conditions. Genes essential for anaerobic growth were identified by screening a mutant library. Eleven out of 1360 investigated mutants were sensitive to anaerobiosis. All 11 mutants were interrupted in the atp locus. These results were further confirmed by phenotypic analysis of respective in-frame deletion and complementation mutants, suggesting that the generation of a proton motive force via F1F0-ATPase is essential for anaerobic proliferation of Listeria monocytogenes.
Lehrstuhl für Mikrobielle Ökologie, Department Biowissenschaften, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.|Abteilung Mikrobiologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung, Technische Universität München, Freising, Germany.
Stefanie
S
Müller-Herbst
Lehrstuhl für Mikrobielle Ökologie, Department Biowissenschaften, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.
Stefanie
S
Wüstner
Lehrstuhl für Mikrobielle Ökologie, Department Biowissenschaften, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.
Anna
A
Mühlig
Abteilung Mikrobiologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung, Technische Universität München, Freising, Germany.
Daniela
D
Eder
Lehrstuhl für Mikrobielle Ökologie, Department Biowissenschaften, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.|Abteilung Mikrobiologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung, Technische Universität München, Freising, Germany.
Thilo
T
M Fuchs
Lehrstuhl für Mikrobiologie, Department Biowissenschaften, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.
Claudia
C
Held
Lehrstuhl für Mikrobiologie, Department Biowissenschaften, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.
Armin
A
Ehrenreich
Lehrstuhl für Mikrobielle Ökologie, Department Biowissenschaften, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.|Abteilung Mikrobiologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung, Technische Universität München, Freising, Germany.
Siegfried
S
Scherer
D000222:Adaptation, Physiological; D000693:Anaerobiosis; D020869:Gene Expression Profiling; D055786:Gene Knockout Techniques; D005798:Genes, Bacterial; D020043:Genes, Essential; D008089:Listeria monocytogenes / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA