Transcription profiling of Sinorhizobium meliloti strain 1021FDC5 grown in liquid, solid or semi-solid media
ABSTRACT: S. meliloti 1021FDC5 was grown at 30ºC in 20 ml of TY broth with shaking to late logarithmic phase (optical density at 600 nm = 1-1.2). After incubation, cells were pelleted, washed twice in MM and resuspended in 2 ml of the latter medium. For time course experiments in liquid, 0.5 ml of the inoculation culture was added to 50 ml of fresh MM. At various times, samples were removed for determining viable cells counts as well as for RNA isolation/preparation (7 and 14 hours). For experiments on plates, 20 ml of MM containing 0.7% (Semisolid) or 1.3% (Solid) agar was dispensed onto each Petri dish and allowed to gel. The plates were air dried at room temperature for 15 min. 0.1 ml of the inoculation culture was plated onto the surface of the plates and allowed to dry for 10 min. The plates were then inverted and incubated at 30ºC.
BACKGROUND: Swarming is a multicellular phenomenom characterized by the coordinated and rapid movement of bacteria across semisolid surfaces. In Sinorhizobium meliloti this type of motility has been described in a fadD mutant. To gain insights into the mechanisms underlying the process of swarming in rhizobia, we compared the transcriptome of a S. meliloti fadD mutant grown under swarming inducing conditions (semisolid medium) to those of cells grown under non-swarming conditions (broth and soli ...[more]
Project description:Hfq-dependent transcriptional alterations in the nitrogen-fixing endosymbiont S. meliloti. Comparison: S. meliloti 1021 strain Vs S. meliloti 1021Dhfq (containing a deletion of the hfq ORF).
Project description:RctR encodes a protein belonging to the GntR family of transcriptional regulators and is involved in regulation of conjugative transfer of symbiotic plasmids of Sinorhizobium meliloti. In order to identify genes differentially expressed in a 1021RctR mutant, the transcriptome of S. meliloti 1021RctR was compared with that of the wild-type 1021, using Sm6kOligo DNA microarrays. Cells of 1021 and 1021RctR were grown at 30C in TY broth to mid logarothmic phase (OD600nm)=0.7-0.8 before RNA isolation.
Project description:P388D1 murine macrophages were cultured in 85 mm tissue culture plates to about semi confluency. L. monocytogenes serotypes (1/2a EGD-e, 4a L99, 4b CLIP80459 and 4b F2365) were infected to the P388D1 cell monolayer at a MOI of 100 per eukaryotic cell. Infection was carried for 45 min and followed by addition of fresh medium containing 20 µg/ml gentamicin. The medium of the plates (containing 20 µg/ml gentamicin) infected with L. monocytogenes serotypes were replaced after 2 h post infection with fresh medium containing 50 µg/ml gentamicin. At each step the plates were washed extensively with 1x PBS. Incubation of the bacterial tissue culture plates was carried out in a humidified incubator for up to 4 h post infection.