V. vulnificus cells (107 CFU/mL) suspended in PBS with 1% BSA were inoculated into each 5 cm segment. After 8 hr, the rabbit was killed and the intestine removed. The fluid within the loops was collected with a syringe and the viable bacterial counts in each determined by plating on 2.5% NaCl HI agar plates. Overnight cultures of V. vulnificus strains were inoculated into fresh 2.5% NaCl HI broth and grown for 2 hr. After staining with Ruthenium red, the bacterial cells were observed with a JEOL JEM 1200 EXП electron microscope (Jeol, Tokyo, Japan). Vibrio vulnificus strains Selleckchem Torin 1 were freshly grown on HI agar plates with 1.5% agar at 37°C. The bacteria

were inoculated onto semisolid HI agar plates containing this website 0.3% agar and incubated for at 37°C for approximately 8 hr, as previously described [31]. HeLa cells were seeded into four-well LabTec chamber slides (Nunc, Naperville, IL, USA) and bacterial adhesion assayed as previously reported [31]. Briefly, V. vulnificus cells were infected at an MOI of 250 for 30 min. HeLa cells were thoroughly washed three times with pre-warmed DMEM and stained with Giemsa solution (Merck, Darmstadt, Germany). Bacterial cells adhering to 90 HeLa cells were counted and the results reported as the average number of adhered bacteria per HeLa cell. Hemolytic and proteolytic activities in bacterial culture supernatants were assayed according to a previous report [12]. β-galactosidase activities

of PvvhA::lacZ and PvvpE::lacZ transcriptional reporters in V. vulnificus strains were assayed as previously described [12]. SPF 7-day-old CD-1 female mice were used for oral administration and 8-week-old mice for intraperitoneal injections. For each dose, five mice were given 10-fold serially diluted log Fossariinae phase bacterial suspensions. For iron-overload experiment, 8-week-old CD-1 mice were injected intraperitoneally with 900 µg of ferric ammonium citrate for 30 min before bacterial challenge. The infected mice were observed for 48 hr and LD50 values calculated by the Reed and Muench method [32]. This animal study was carried out in strict accordance with the recommendations of the Guide for the Care and Use of Laboratory Animals

of the Korean Food and Drug Administration. The protocol was approved by the Chonnam National University Committee on the Ethics of Animal Experiments. All efforts were made to treat the mice humanely. Human cervical adenocarcinoma HeLa cells (Korean Cell Line Bank, Seoul, Korea) were maintained in high-glucose DMEM with 10% FBS (Gibco Invitrogen, Auckland, New Zealand) in a 37°C incubator with 5% CO2. HeLa cells cultured in eight-well glass chamber plates (Nalge Nunc International, Rochester, NY, USA) were infected with V. vulnificus strains at a MOI of 100 for 1 hr. F actin was visualized by Alexa Fluor 594-conjugated phalloidin and nuclei were stained with 4′,6-diamidino-2-phenylindole (Molecular Probes, Eugene, OR, USA) as described previously [7].