Occurrence, Molecular Characterization and Phylogenetic Relationship of <i>Aspergillus </i>Species Isolated from Garri Sold in Benue State, North Central, Nigeria

Characterization and identification of molds based on cultural and morphological characteristics are often not reliable and frail with limitations. The occurrence of Aspergillus species in garri on sale in markets in Benue State, Nigeria, was studied by molecular techniques. Aspergillus species were isolated and purified on Potato Dextrose Agar. DNA from the purified isolates was extracted using the ZR fungal DNA miniprep and amplified by PCR mix made up of 12.5 μL of Taq 2X Master Mix. Primer sequences for the fungi characterization were internal transcribed spacers ITS 4 and ITS 5. The phylogenetic tree was plotted between the isolated organisms and reference sequences and evolutionary analysis was conducted in MEGA X. Result revealed that one thousand, six hundred and forty-six Aspergilli were isolated comprising of 980 and 666 isolates from the white and yellow garri respectively. Aspergillus flavus, A. fumigatus, A. niger, A. aculeatinus, and A. aculeatus were identified. Twenty percent (20%) of the strains had aflatoxin D structural gene, 50% amplified AFLP and 70% of the strains expressed AFLQ genes needed for the biosynthesis of aflatoxin B1. Majority of the strains that showed the expression of these structural genes were consistent with Aspergillus flavus. Phylogenetic tree showed a close relationship among the isolates and their most identical sequence in the NCBI database.

Aflatoxin Contamination of Garri Sold in Some Selected Markets in Benue State, North Central, Nigeria

The presence of aflatoxin-producing fungi in foods consumed by humans and animals has often resulted in the health hazards and even death. Aflatoxin contaminations of garri sold in some markets of Benue State, Nigeria, were studied, to ascertain the health implications on the consumers. Sixty garri samples comprising of 30 white garri and 30 yellow garri respectively were studied. The garri samples were ground to a particle size of 250 μm using a sterile blender. The total aflatoxin was extracted using 70% (v/v) methanol. The total aflatoxin concentration was detected and quantified using the Enzyme-Linked Immunosorbent Assay technique. The results showed that overall, 76.67% of the white garri samples and 80% of the yellow garri samples were aflatoxin positive. The total aflatoxin concentration in white garri ranged from 0.3 μg/kg to 2.4 μg/kg and 0.2 to 2.4 μg/kg in yellow garri respectively. The total mean aflatoxin across the States recorded was 2.96 μg/kg in white garri and 3.07 μg/kg in yellow garri. All the aflatoxin-positive garri samples of both the white and yellow garri were within the NAFDAC permissible aflatoxin level. Even though the aflatoxins are within the approved standard consumable limits, the continuous consumption of these doses over a long period of time could lead to the accumulation of these toxins in the body. These may eventually constitute a toxic health challenge.

Chemosystematics Studies on Six Varieties of <i>Mangifera indica</i>L.

Taxonomic investigation was carried out on six (6) varieties of Mangifera indica (Julie, Broken, Peter, Kerosene, Opioro and Big fibre) using chemosystematics evidence. Extracts obtained from the leaf of each variety were phyto-chemically screened and quantified. Gravimetric and spectroscopic approaches were adopted in the quantification of active principles common to all the six varieties. Binary matrices computed from qualitative assessment were analysed to yield a dendrogram using the Average Linkage Method. Quantitative values were subjected to appropriate descriptive and inferential statistical analysis. All varieties possessed alkaloid except Big-fibre. Peter and Kerosene varieties lacked saponin, an active principle present in other varieties. Anthraquinone was present in all except in Julie and Opioro. Five out of the six varieties lacked phlobatannin. All varieties had tannin, steroid, flavonoid and reducing sugar. Tannin was lowest in Big-fibre (0.43%) but highest in Opioro (2.41%). Steroid ranged from 3.8% in Opioro to 9.0% in Julie with a standard deviation of 1.84. Julie variety recording the lowest composition in flavonoid (0.01%) and reducing sugar (0.04%) components was notable. Comparison of the mean values of phytochemicals has shown a statistically significant difference (p = 0.0005) with a large F-value (18.244). Using the LSD mean separation, steroid was the most remarkable phytochemical contributing to the significant differences. Dendrogram revealed very close relationship between Julie and Opioro varieties. The remaining four were divergent and distinct although Broken and Peter varieties arose from the same ancestral lineage with Julie and Opioro. However, Big-fibre and Kerosene varieties were clearly different from rest belonging to a different phylogenetic ancestor. With these remarkable differences, they ought to be given special taxonomic and systematic review for appropriate nomenclatural assignment. The six varieties of Mangifera indica investigated are thus clearly partitioned and therefore recommended to be circumscribed. This approach is maiden, and considered innovative as it is employed in this study for the first time in the taxonomy of Mangifera.