Table of Contents

Abstract: Toxins are ubiquitous in nature and as such they impact our daily life. Toxins may come from a wide variety of sources and influence a myriad of biological functions. Research on toxins may address their production, structure, chemical properties, biological activity, and economic impact. On the one hand, toxins may be used to decipher biological mechanisms, to favourably influence disease or to combat unwanted organisms. On the other hand, toxins may be a hazard jeopardizing health of humans, animals or plants. [...]

Abstract: In vitro trials were conducted to evaluate the effect of Azadirachta indica (neem) extracts on mycelial growth, sporulation, morphology and ochratoxin A production by P. verrucosum and P. brevicompactum. The effect of neem oil extract from seeds and leaf was evaluated at 0.125; 0.25 and 0.5% and 6.25 and 12.5 mg/mL, respectively, in Yeast Extract Sucrose (YES) medium. Ochratoxin A production was evaluated by a thin-layer chromatography technique. Oil extracts exhibited significant (p ≤ 0.05) reduction of growth and sporulation of the fungi. No inhibition of ochratoxin A production was observed. Given its accessibility and low cost, neem oil could be implemented as part of a sustainable integrated pest management strategy for plant disease, as it has been shown to be fungitoxic by inhibition of growth and sporulation.

Abstract: River pollution in Taiwan is rather serious, but so far there have been no reports of fish intersex problems. This report reveals that 50% male tilapia in the Era-Jiin River of southern Taiwan were found to be feminized in an October 8, 1994 collection from station EJ-2 of this river. After discounting all other possible causative factors, and correlating with endocrine disrupting chemicals found in this river, we suggest that there is a great possibility that the occurrence of intersex tilapia was caused by these chemicals. The above finding suggests that greater attention needs to be given to endocrine disrupting chemicals problems.

Abstract: The purpose of this study was to establish a model of delayed type hypersensitivity (DTH) reaction in the ear skin of large animals such as adult Yucatan pigs, which may aid in evaluating the efficacy of therapeutic modalities of newly developed anti-inflammatory drugs. The pigs were sensitized with oxazolone, re-challenged with the same irritant six days later, and dosed with either vehicle or with cyclosporine A (CsA) before and after challenge. CsA reduced the redness, inhibited the accumulation of ear fluid and inflammatory cells, as well as the release of the inflammatory mediators. Further, CsA inhibited the proliferation of T cells collected from the spleens or PBMCs of CsA-treated pigs when these cells were stimulated in vitro with PMA plus Ionomycin. These results indicate that pig skin can be used to evaluate modalities for the purpose of developing drugs that may be used to treat DTH in humans.

Abstract: Biosynthesis of the toxic and carcinogenic aflatoxins (AFs) requires the activity of more than 27 enzymes. The roles in biosynthesis of newly described enzymes are discussed in this review. We suggest that HypC catalyzes the oxidation of norsolorinic acid anthrone; AvfA (AflI), the ring-closure step in formation of hydroxyversicolorone; HypB, the second oxidation step in conversion of O-methylsterigmatocystin to AF; and HypE and NorA (AflE), the final two steps in AFB₁ formation. HypD, an integral membrane protein, affects fungal development and lowers AF production while AflJ (AflS), has a partial methyltransferase domain that may be important in its function as a transcriptional co-activator.