Phytotoxic Components Produced by Pathogenic Fusarium against Morning Glory

A pathogenic isolate of Fusarium, F. oxysporum f. sp. batatas O-17 (PF), causes wilt disease in leaf etiolation in sweet potato (Ipomoea batatas) and morning glory (Ipomoea tricolor). Extracts from PF cultures were screened for phytotoxic components using a growth inhibition assay with morning glory seedlings. The extracts were fractionated using differential solvent extraction and two active compounds, ergosterol and fusalanipyrone, were isolated from the less-polar fraction. Growth inhibition of morning glory seedlings showed a sigmoidal doseresponse relationship, with fusalanipyrone exhibiting a two order of magnitude higher EC50 value than ergosterol (18 nᴍ and 1.6 μᴍ, respectively). Both compounds showed lower growth inhibition activity towards lettuce seedlings (Lactuca sativa). This study provides information on the phytotoxic components of PF and discusses the mechanism behind PFfinduced phytotoxicity.

Drug therapy: dose-response relationship of oral mesalazine in inflammatory bowel disease

Mesalazine is widely used in the treatment of inflammatory bowel disease. Little is known about the doseresponse relationship and about possible dose related side effects. In ulcerative colitis higher dosages of mesalazine (3 g) are more effective in maintaining a remission than lower dosages (1.5 g). In mild to moderately active ulcerative colitis, studies also indicate that higher dosages might be more effective in inducing remission. Dose-comparing studies in Crohn's disease are even more sparse, but the available results indicate higher efficacy at higher dose levels.None of the known side effects of mesalazine are clearly dose-related. A pH-dependent release system, however, can cause a sudden release of high doses of mesalazine. Consequent peak levels in serum have been implicated in mesalazine induced nephrotoxicity. In conclusion, despite the current practice of using increasing dosages of mesalazine in inflammatory bowel disease, both efficacy and safety have been established tentatively.