Inactivation of the SecA2 protein export pathway in Listeria monocytogenes promotes cell aggregation, impacts biofilm architecture and induces biofilm formation in environmental condition. (18th September 2013)

• Record Type: Journal Article
• Authors: Renier, Sandra; Chagnot, Caroline; Deschamps, Julien; Caccia, Nelly; Szlavik, Julie; Joyce, Susan A.; Popowska, Magdalena; Hill, Colin; Knøchel, Susanne; Briandet, Romain; Hébraud, Michel; Desvaux, Mickaël
• Is Part Of: Environmental microbiology. Volume 16:Number 4(2014:Apr.)
• Page Start: 1176
• Page End: 1192
• Publication Date: 2013-09-18
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.12257
• Languages: English
• ISSNs: 1462-2912

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p> <italic>Listeria monocytogenes</italic> has a dichotomous lifestyle, existing as an ubiquitous saprophytic species and as an opportunistic intracellular pathogen. Besides its capacity to grow in a wide range of environmental and stressful conditions, <italic>L. monocytogenes</italic> has the ability to adhere to and colonize surfaces. Morphotype variation to elongated cells forming rough colonies has been reported for different clinical and environmental isolates, including biofilms. This cell differentiation is mainly attributed to the reduced secretion of two <italic>SecA</italic>2‐dependent cell‐wall hydrolases, <italic>CwhA</italic> and <italic>MurA</italic>. <italic>SecA</italic>2 is a non‐essential <italic>SecA</italic> paralogue forming an alternative translocase with the primary Sec translocon. Following investigation at temperatures relevant to its ecological niches, i.e. infection (37°C) and environmental (20°C) conditions, inactivation of this <italic>SecA</italic>2‐only protein export pathway led, despite reduced adhesion, to the formation of filamentous biofilm with aerial structures. Compared to the wild type strain, inactivation of the <italic>SecA</italic>2 pathway promoted extensive cell aggregation and sedimentation. At ambient temperature, this effect was combined with the abrogation of cell motility resulting in elongated sedimented cells, which got knotted and entangled together in the course of filamentous‐biofilm development. Such a cell differentiation provides a decisive advantage for listerial surface colonization under environmental condition. As further discussed, this morphotypic conversion has strong implication on listerial physiology and is also of potential significance for asymptomatic human/animal carriage.</p> </abstract>