title: Light Modulates Metabolic Pathways and Other Novel Physiological Traits in the Human Pathogen Acinetobacter baumannii.
abstract: Light sensing in chemotrophic bacteria has been relatively recently ascertained. In the human pathogenAcinetobacter baumannii, light modulates motility, biofilm formation, and virulence through the blue-light-sensing-using flavin (BLUF) photoreceptor BlsA. In addition, light can induce a reduction in susceptibility to certain antibiotics, such as minocycline and tigecycline, in a photoreceptor-independent manner. In this work, we identified new traits whose expression levels are modulated by light in this pathogen, which comprise not only important determinants related to pathogenicity and antibiotic resistance but also metabolic pathways, which represents a novel concept for chemotrophic bacteria. Indeed, the phenylacetic acid catabolic pathway and trehalose biosynthesis were modulated by light, responses that completely depend on BlsA. We further show that tolerance to some antibiotics and modulation of antioxidant enzyme levels are also influenced by light, likely contributing to bacterial persistence in adverse environments. Also, we present evidence indicating that surfactant production is modulated by light. Finally, the expression of whole pathways and gene clusters, such as genes involved in lipid metabolism and genes encoding components of the type VI secretion system, as well as efflux pumps related to antibiotic resistance, was differentially induced by light. Overall, our results indicate that light modulates global features of theA. baumanniilifestyle.IMPORTANCEThe discovery that nonphototrophic bacteria respond to light constituted a novel concept in microbiology. In this context, we demonstrated that light could modulate aspects related to bacterial virulence, persistence, and resistance to antibiotics in the human pathogenAcinetobacter baumanniiIn this work, we present the novel finding that light directly regulates metabolism in this chemotrophic bacterium. Insights into the mechanism show the involvement of the photoreceptor BlsA. In addition, tolerance to antibiotics and catalase levels are also influenced by light, likely contributing to bacterial persistence in adverse environments, as is the expression of the type VI secretion system and efflux pumps. Overall, a profound influence of light on the lifestyle ofA. baumanniiis suggested to occur.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Rosario, Argentina.|Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Gabriela L
authors.initials: GL
authors.lastname: Müller
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Rosario, Argentina.
authors.forename: Marisel
authors.initials: M
authors.lastname: Tuttobene
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Rosario, Argentina.
authors.forename: Matías
authors.initials: M
authors.lastname: Altilio
authors.affiliation: Instituto de Química Rosario (IQUIR), CONICET, Rosario, Argentina.
authors.forename: Maitena
authors.initials: M
authors.lastname: Martínez Amezaga
authors.affiliation: Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, California, USA.
authors.forename: Meaghan
authors.initials: M
authors.lastname: Nguyen
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Rosario, Argentina.|Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Pamela
authors.initials: P
authors.lastname: Cribb
authors.affiliation: Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Larisa E
authors.initials: LE
authors.lastname: Cybulski
authors.affiliation: Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, California, USA.
authors.forename: María Soledad
authors.initials: MS
authors.lastname: Ramírez
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Rosario, Argentina.|Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Silvia
authors.initials: S
authors.lastname: Altabe
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Rosario, Argentina mussi@cefobi-conicet.gov.ar.|Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: María Alejandra
authors.initials: MA
authors.lastname: Mussi
mesh_terms: D040981:Acinetobacter baumannii / Q000502:physiology* / Q000528:radiation effects*; D000975:Antioxidants / Q000378:metabolism; D008027:Light; D050356:Lipid Metabolism / Q000528:radiation effects; D053858:Metabolic Networks and Pathways / Q000528:radiation effects*; D010648:Phenylacetates / Q000378:metabolism; D013501:Surface-Active Agents / Q000378:metabolism; D014199:Trehalose / Q000096:biosynthesis; D000069376:Type VI Secretion Systems / Q000528:radiation effects
chemical_list: D000975:Antioxidants; D010648:Phenylacetates; D013501:Surface-Active Agents; D000069376:Type VI Secretion Systems; D014199:Trehalose; C025136:phenylacetic acid
keywords: Acinetobacter baumannii; light; metabolism