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Intact pathogenic Mycoplasma hyopneumoniae at 100 microg protein ml(-1) induced transcription of proinflammatory cytokines such as cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-alpha, interleukin(IL)-1, IL-6 and inducible nitric oxide synthase (iNOS) in RAW 264.7 cells. After pretreatment with 50 microg surfactin C/ml, purified from Bacillus subtilis, transcription of the COX-2, IL-1beta, IL-6 and iNOS genes induced by M. hyopneumoniae was inhibited by 43%, 82%, 72% and 59%, respectively.

To evaluate the anti-endotoxin activity of surfactin C, we studied its lipopolysaccharide-binding activity in vitro and therapeutic efficacy in experimental models of gram-negative septic shock. The ability of surfactin C to bind LPS from Escherichia coli O111:B4 was determined using a limulus chromogenic assay. Male ICR mice and Sprague-Dawley rats were given intraperitoneal administration of 1x10(9) colony forming units of E. coli ATCC 25922. After bacterial challenge, all animals were randomized to receive intraperitoneally saline, polymyxin B or surfactin C. Surfactin C not only completely bound to the LPS (its median effective concentration being 13.75 microM) but also improved the survival and reduced of the number of inoculated bacteria in the mouse model of septic shock. Surfactin C reduced the plasma endotoxin, tumor necrosis factor-alpha and nitric oxide levels in response to septic shock in rats.

This study was designed to investigate the effect of surfactin C, which is derived from Bacillus subtilis, on platelet aggregation and homotypic leucocyte aggregation. Surfactin C strongly and dose-dependently inhibited platelet aggregation, which was stimulated both by thrombin (0.1 U mL(-1)), a potent agonist that activates the G protein-coupled protease receptor, and by collagen (5 microg mL(-1)), a potent ligand that activates alpha(IIb)beta(3) with IC50 values (concentration inhibiting platelet aggregation by 50%) of 10.9 and 17.0 microM, respectively. Moreover, surfactin C significantly suppressed the intracellular Ca(2+) mobilization in thrombin-activated platelets. Surfactin C, however, did not affect various integrin-mediated U937 cell aggregation, implying that the anti-platelet activity of surfactin C was not due to its detergent effect but by its action on the downstream signalling pathway. Therefore, the results suggest that surfactin C may have a beneficial therapeutic effect on aberrant platelet aggregation-mediated cardiovascular diseases.

Platelet aggregation was inhibited and the density of platelet-rich plasma (PRP) clots was decreased by the preincubation of PRP with surfactins, an acidic lipopeptide of Bacillus subtilis complex BC1212 isolated from soybean paste, in dose-dependent manner. Our findings suggest that surfactins are able to prevent a platelet aggregation leading to an inhibition of additional fibrin clot formation, and to enhance fibrinolysis with facilitated diffusion of fibrinolytic agents.

The anti-inflammatory activity of the surfactin C derived from Bacillus subtilis isolate was investigated in lipopolysaccharide (LPS, 1 microg ml(-1))-treated mouse RAW 264.7 cells. LPS increased mRNA transcription of cyclooxygenase (COX)-2, interleukin (IL)-1beta and inducible nitric oxide synthase (iNOS). However, surfactin C at 50 microg ml(-1 )inhibited the LPS-induced increase in the transcription of IL-1beta and iNOS and nitric oxide (NO) production in a dose-dependent manner.