Oxidative enzymes activity during abiotic and biotic stresses in Zea mays leaves and roots exposed to Cu, methyl jasmonate and Trigonotylus caelestialium.

The activities of antioxidative enzymes, i.e. superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX), in the leaves and roots of Zea mays L. plants exposed to abiotic (methyl jasmonate, MJ, or/and copper, Cu) and biotic (Trigonotylus caelestialium) factors were examined. The contribution of MJ as a signal molecule in the defense mechanism against abiotic and biotic stresses was studied. All plants were cultivated hydroponically and divided into three groups: not treated by abiotic factors (control), treated by MJ only (MJ) and by MJ and Cu (MJ + Cu) and in each group half of the plants were exposed to T. caelestialium attack. The enzymatic activities of SOD, CAT, APX, and GPX in the leaves were higher in the insect-treated than non-insect-treated control plants, but lower in both MJ + Cu- or MJ- and insect-treated plants. In the roots, the enzyme activities were elevated in all insect-treated plants with the highest rise in MJ + Cu, in comparison with the MJ-treated plants. The results showed that MJ and MJ + Cu were efficient in reducing the activity of the antioxidative enzymes in the leaves under the insect influence by elevating enzyme activity in the roots.

In vitro evaluation of antifungal and cytotoxic activities as also the therapeutic safety of the oxidized form of amphotericin B.

The aim of this study was to evaluate the antifungal and cytotoxic activities of the oxidized form of amphotericin B (AmB-Ox) as well as to determine whether oxidation process of AmB is therapeutically beneficial in vitro. The antifungal activity was estimated against Candida albicans ATCC 10231 and Candida parasilosis ATCC 22019 by broth microdilution method according to the NCCLS M27-A2 standards. The in vitro cytotoxicity was evaluated using normal green monkey kidney cells (GMK) by MTT assay. The obtained results demonstrated that AmB-Ox possesses 16-fold decreased antifungal properties against the two Candida strains and 5-fold lower cytotoxic activity towards GMK cells in comparison with AmB. The therapeutic safety in vitro assessed by calculating the ratio between cytotoxicity (CC50 value) to antifungal activity (MIC value) showed that oxidation of AmB is a very unfavourable process in vitro, because leads to formation of derivative (AmB-Ox) that lost antifungal properties much more rapidly than cytotoxic activity. Thus, the process of the oxidation of AmB in vivo (if it occurs) can be also highly harmful for patient.