We examined the effect of phosphate-buffered saline (PBS) solution with different pH values on the formation of porosity in the DNA/chitosan complexes, and evaluated the intercalation behavior of the complexes . Four different PBS solutions with pH = 6.0, 7.0, 7.4, and 7.8 were used for rinsing water-insoluble DNA-chitosan complexes . All complexes showed high porosities ranging from 83 to 95%. Rinsing with PBS at pH 7.0, 7.4, and 7.8 reduced the porosity of the DNA-chitosan complexes. Re-rinsing with PBS at pH 7.4 reduced the porosity of the DNA-chitosan complex rinsed with PBS at pH 6 .0. The appearances for porous formation were influenced by the differences in pH of PBS . Daunorubicin hydrochloride intercalated and bound in the grooves of DNA within all of the DNA-chitosan complexes , indicating that DNA in the complexes maintained its double-stranded helical structure. These results suggested that PBS-rinsed DNA -chitosan complex is promising as a scaffold material in tissue engineering.

To investigate the usefulness of multi-color luciferase technology as reporter genes in higher plants, we assayed the transient expression of click beetle luciferase genes introduced into plant cells by microprojectile bombardment. Although their expression levels were relatively low, luminescence from green and red luciferases were separable under the CCD camera equipped with interference filters. Results of time-course experiments and the inducible promoter assay suggest that the multi-color luciferase system optimized primarily for mammalian cells is also applicable to monitor reporter activities in plant cells.

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The fungicide tolprocarb (TPC) is a melanin biosynthesis inhibitor, but it may also have another mode of action. Here in tests of TPC for inducing plant systemic acquired resistance (SAR), TPC induced promoter activity of the tobacco pathogenesisrelated gene PR-1a in Arabidopsis thaliana and genes for PBZ1, β-1,3-glucanase, and chitinase 1 in the defense-related salicylic acid (SA) signaling pathway in rice, but not genes for the jasmonate signaling pathway. Probenazole (PBZ), a commercially used plant defense activator, induced genes in both signaling pathways. The antibacterial activity of TPC was equivalent to that of PBZ. Irrigation with 200 μM TPC prevented growth by Pseudomonas syringae pv. maculicola in A. thaliana, and 30 μM TPC inhibited Xanthomonas oryzae pv. oryzae growth in rice. The results of this study suggest that TPC functions not only as a melanin biosynthesis inhibitor but also as an SAR inducer and is applicable as a novel bacterial control agent that induces SAR activity in both A. thaliana and rice.