Finally, plant-root and epiphytic biofilms have become an interest for microbiologists interested in crop protection or

crop enhancement, as microbial community structures have demonstrated repeatedly their influence on plant health and agricultural yield [37]. In this report we PLX-4720 datasheet examine swarming motility and biofilms formed by the aerobic soil bacterium Variovorax paradoxus. We demonstrate that swarming is a fundamental behavior of this microorganism, and examine the effect of Congo Red, an acidic dye that disrupts flagellar function, on swarming. In this context we observe the production of a wetting agent, possibly a surfactant. We examine carbon sources, nitrogen sources and water content in the agar as key factors in swarming motility. We also examine the biofilms formed under similar nutrient conditions in a 96-well polystyrene microtiter plate assay, as well as the role of fluid shear on biofilm formation by V. paradoxus attached to a glass surface.

Finally, we observe that dense, structurally complex biofilms are formed readily by this microorganism in continuous culture. We suggest that V. paradoxus EPS is a valuable additional model of complex selleck kinase inhibitor coordinated surface behavior in proteobacteria, and can be used to understand the role of this microbial ARN-509 population in soil and rhizosphere environments. These surface behaviors and the signals

that drive them are likely related to the nutrient cycles driven by plant root exudates in the rhizosphere. Methods Bacteria used V. paradoxus strain EPS was cultivated from the soil in the Land Lab at CSU San Bernardino. Cisplatin purchase Pseudomonas aeruginosa PAO1 was obtained from the Pseudomonas Genetic Stock Center (East Carolina University), S17-1 was obtained from ATCC (ATCC# 47055). Swarming motility Swarming motility was routinely assayed using freshwater (FW) base medium (Table 1) [5] solidified with 0.5% agarose (Low EEO, Fisher Scientific), supplemented with 1:1000 dilutions of a trace metal mixture (ATCC TM-S) and a vitamin mixture (ATCC TV-S). This medium was buffered to pH 7 with 5 mM MOPS. Additional swarming assays were performed using M8/M9 minimal media [22](Table 1, Difco) supplemented with the same constituents. In all swarming motility assays, triplicate samples on an individual petri dish were measured, and diameters recorded to the nearest millimeter in each measurement. Table 1 Composition of minimal media used (per liter) M8/M9 salts FW medium 0.2% w/v carbon sourcea 0.2% w/v carbon sourcea 0.1% w/v nitrogen sourcea, b 0.1% w/v nitrogen sourcea 3.0 g KH2PO4 0.2 g KH2PO4 8.18 g Na2HPO4 dihydrate   0.5 g Mg2SO4heptahydrate 0.15 g Na2SO4   0.4 g MgCl2 hexahydrate 0.15 g CaCl2dihydrate 0.1 g CaCl2 dihydrate 0.5 g NaCl 1.