Involvement of the Type IX Secretion System in Capnocytophaga ochracea Gliding Motility and Biofilm Formation

Abstract

dCapnocytophaga ochracea is a Gram-negative, rod-shaped bacterium that demonstrates gliding motility when cultured on solid agar surfaces. C. ochracea possesses the ability to form biofilms; however, factors involved in biofilm formation by this bacterium are unclear. A type IX secretion system (T9SS) in Flavobacterium johnsoniae was shown to be involved in the transport of proteins (e.g., several adhesins) to the cell surface. Genes orthologous to those encoding T9SS proteins in F. johnsoniae have been identified in the genome of C. ochracea; therefore, the T9SS may be involved in biofilm formation by C. ochracea. Here we constructed three ortholog-deficient C. ochracea mutants lacking sprB (which encodes a gliding motility adhesin) or gldK or sprT (which encode T9SS proteins in F. johnsoniae). Gliding motility was lost in each mutant, suggesting that, in C. ochracea, the proteins encoded by sprB, gldK, and sprT are necessary for gliding motility, and SprB is transported to the cell surface by the T9SS. For the ⌬gldK, ⌬sprT, and ⌬sprB strains, the amounts of crystal violet-associated biofilm, relative to wild-type values, were 49%, 34%, and 65%, respectively, at 48 h. Confocal laser scanning and scanning electron microscopy revealed that the biofilms formed by wild-type C. ochracea were denser and bacterial cells were closer together than in those formed by the mutant strains. Together, these results indicate that proteins exported by the T9SS are key elements of the gliding motility and biofilm formation of C. ochracea.

Sickeningly Sweet: L‐rhamnose stimulates Flavobacterium columnare biofilm formation and virulence

“…), and more recent work has shown that Capnocytophaga ochracea, another Gram‐negative bacterium involved in periodontal disease utilizes its gliding motility system to facilitate the formation of biofilms (Kita et al . ). While little to no work has been done on the gliding motility system of F. columnare , in the terrestrial F. johnsoniae a broad number of studies have described gliding motility and the T9SS mechanisms (McBride & Nakane ).…”

“…Upon activation of an iron-depleted LV-359-01 phenotype, a survival phenotype may prevent resources from going towards biofilm formation even when adequate iron is added into the system. Interestingly, the depletion of iron has been shown to inhibit P. aeruginosa biofilms through the disruption of quorum sensing and twitching motility systems (Cai et al 2010), and more recent work has shown that Capnocytophaga ochracea, another Gram-negative bacterium involved in periodontal disease utilizes its gliding motility system to facilitate the formation of biofilms (Kita et al 2016). While little to no work has been done on the gliding motility system of F. columnare, in the terrestrial F. johnsoniae a broad number of studies have described gliding motility and the T9SS mechanisms (McBride & Nakane 2015).…”

The Carboxy-Terminal Region of Flavobacterium johnsoniae SprB Facilitates Its Secretion by the Type IX Secretion System and Propulsion by the Gliding Motility Machinery

“…The importance of T9SSs in the nutrition, physiology, motility, and virulence of members of the phylum Bacteroidetes has been demonstrated (1,3,19,36,(38)(39)(40). Most of the proteins with easily predicted functions that are secreted by T9SSs have type A CTDs.…”

A conserved motif of Porphyromonas Type IX secretion effectors C-terminal secretion signal specifies interactions with the PorKLMN core complex

“…Other Bacteroidetes members use the T9SS for the secretion of adhesins required for gliding motility, or enzymes required for supplying carbon, heme and metal sources [5][6][7][8]. P. gingivalis, the main causative agent of periodontal diseases, secretes a plethora of virulence factors at its cell surface, including the gingipains that play an important role in gum infections [9].…”