Molecular characterisation of pathogenic fungi of maize grains

Fungi differ from each other phylogenetically, ecologically, metabolically, biochemically, physiologically and morphologically. Despite industrial, medicinal and agricultural importance of fungi, their identification remains daunting for young mycologists. A study was conducted to identify the common fungal pathogens causing post-harvest contamination of stored maize grains purchased from the Rumuokoro daily market in Port Harcourt, Rivers State. Fungal cultures were isolated and morphologically identified using both standard blotter method and Potato Dextrose Agar (PDA) media. The DNA of the most common fungal isolate, coded M-11, was molecularly characterised using Internal Transcribed Spacer 1 (ITS-1) molecular marker. The M-11 isolate DNA sequence was aligned using the Basic Local Alignment Search Tool for nucleotide (BLASTN) 2.8.0 version of the National Centre for Biotechnology Information (NCBI) database. The amplified DNA sequence of the millet isolates yielded 569 base pairs. The results indicated that the M-11 isolate sequence was 89.34% identical to Aspergillus flavus var. flavus strain CSS 130026 and 88.11% identical to Aspergillus flavus isolate AA 133. The above outcome shows that one of the causal organisms associated with stored maize grains is Aspergillus flavus. It is anticipated that these results will improve on the current information available, provide information for developing effective disease control strategy for alleviating the post-harvest losses caused by Aspergillus flavus and also provide a foundation for further study of potential mycotoxic effect of consuming diseased maize seeds

Potent Antioxidant and Genoprotective Effects of Boeravinone G, a Rotenoid Isolated from Boerhaavia diffusa

Background and Aims: Free radicals are implicated in the aetiology of some gastrointestinal disorders such as gastric ulcer, colorectal cancer and inflammatory bowel disease. In the present study we investigated the antioxidant and genoprotective activity of some rotenoids (i.e. boeravinones) isolated from the roots of Boerhaavia diffusa, a plant used in the Ayurvedic medicine for the treatment of diseases affecting the gastrointestinal tract. Methods/Principal Findings: Antioxidant activity has been evaluated using both chemical (Electron Spin Resonance spectroscopy, ESR) and Caco-2 cells-based (TBARS and ROS) assays. DNA damage was evaluated by Comet assay, while pERK 1/2 and phospho-NF-kB p65 levels were estimated by western blot. Boeravinones G, D and H significantly reduced the signal intensity of ESR induced by hydroxyl radicals, suggesting a scavenging activity. Among rotenoids tested, boeravinone G exerted the most potent effect. Boeravinone G inhibited both TBARS and ROS formation induced by Fenton's reagent, increased SOD activity and reduced H 2O 2-induced DNA damage. Finally, boeravinone G reduced the levels of pERK 1 and phospho-NF-kB p65 (but not of pERK 2) increased by Fenton's reagent. Conclusions: It is concluded that boeravinone G exhibits an extraordinary potent antioxidant activity (significant effect in the nanomolar range). The MAP kinase and NF-kB pathways seem to be involved in the antioxidant effect of boeravinone G. Boeravinone G might be considered as lead compound for the development of drugs potentially useful against those pathologies whose aetiology is related to ROS-mediated injuries

Effect of Zn Substitutions in YBa2Cu3O6 + x Phases on Reactivity during the Ammoxidation of Toluene

Zn substitution in Y-Ba-Cu-O phases influences the catalytic ammoxidation of toluene. The activity for formation of both benzonitrile and CO2 at low and high O2 pressures, respectively, decreases strongly with increasing Zn content up to 4%. Above this substitution level, the activity, however, increases slightly. Characterisations of the surface by XPS and of the bulk by XRD analysis, indicate the presence of overlayers on the catalysts. In these overlayers, irrespective of the Zn content of catalysts, Cu1 states predominate at low O2 pressure and Cu11 at high pressure. These states are associated with selective and non-selective properties, respectively. The activity of the catalysts shows a general tendency to increase with surface copper concentrations as found from XPS studies. However, strong deviations from linearity indicate that the activity of the overlayer is greatly influenced by the bulk acting as a support