The novel genes soxFGH were identified, completing the sox gene cluster of Paracoccus pantotrophus coding for enzymes involved in lithotrophic sulfur oxidation. The periplasmic SoxF, SoxG, and SoxH proteins were induced by thiosulfate and purified to homogeneity from the soluble fraction. soxF coded for a protein of 420 amino acids with a signal peptide containing a twin-arginine motif. SoxF was 37% identical to the flavoprotein reconstitute a system able to perform thiosulfate-, sulfite-, sulfur-, and hydrogen sulfide-dependent cytochrome c reduction, and this system is the first described for oxidizing different inorganic sulfur compounds. SoxF slightly inhibited the rate of hydrogen sulfide oxidation but not the rate of sulfite or thiosulfate oxidation. From use of a homogenote mutant with an in-frame deletion in soxF and complementation analysis, it was evident that the soxFGH gene products were not required for lithotrophic growth with thiosulfate.

With a 2.9-mM concentration of unlabelled bovine serum albumin (BSA), the FITC-albumin transport (2 mg included) across the omental monolayer (0.48 ± 0.16 mg/ml/30 min) was found to be significantly reduced as compared with the interstitial BSA concentration (290 µM) as it is the case, e.g., in peritonitis (0.79 ± 0.09 mg/ml/30 min). Adding 10 µg lipopolysaccharide (LPS)/ml from Escherichia coli, serotype 0128:B12, we did not see any differences from the control. Cultured mesothelial cells took up double the amount of FITC-albumin (4.2 ± 0.13 µg/10⁵ cells/30 min) and in the presence of LPS the uptake of FITC-albumin was reduced to half the control (2.15 ± 0.47 µg/10⁵ cells/30 min). The results reveal the active participation of the mesothelium because high concentrations of BSA reduced exocytosis and stimulated endocytosis. Applying 10 µg/ml of LPS turned out to influence endocytosis and to reduce it at a high BSA concentration.