Edible plants such as sweet potato are sources of natural antioxidants that can be exploited in the management and treatment of insulin resistance. This present study investigated the effects of the extracts of an orange-fleshed sweet potato on oxidative stress biomarkers (glutathione status and lipid peroxidation) and activities of antioxidant enzymes (catalase, CAT and glutathione peroxidase, GPx) in palmitate-induced insulin resistant C2C12 cells. The intracellular antioxidant status of the cells was also measured using Ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays. Furthermore, this study determined the effect of the extracts on the regulation of some type 2 diabetes associated genes; glucose transporter 4 (glut4), Nuclear respiratory factor 1 (nrf1), Myocyte enhanced factor 2A (mef2a), Carnitine palmitoyltransferase 1 (cpt1) and Acetyl-CoA carboxylase 2 (acc2). The results showed a significant (p < 0.05) increase in intracellular GSH level, a significant reduction in the level of malonaldehyde and a significant improvement in the intracellular antioxidant status upon treatment of the insulin resistant cells with the extracts. The extracts were also able to positively modulate the expression levels of the type 2 diabetes associated genes. On the other hand, HPLC-MS analysis of the extracts showed the presence of polyphenols which could have contributed to the bioactivity of the extracts through their antioxidant effects.

Using nematode resistant varieties is one of effective and environmental sound strategies being adopted in the management of economically important Meloidogyne species. Wild cucumber (Cucumis africanus) has been reported to possess resistance to Meloidogyne species. Two mechanism of nematode resistance, pre- and post-penetration resistance, had been identified, with post-penetration mechanism being used in plant breeding programs and crop rotation systems. The objective of this study was to determine the mechanism of nematode resistance in C. africanus to M. incognita and M. javanica. 6 weeks old C. africanus seedlings were separately inoculated with 100 s-stage juveniles (J2) of M. incognita and M. javanica. For 30 days, five seedlings were harvested from both M. incognita and M. javanica experiments every other day. Seedlings’ roots were examined for necrotic spots, rootlet interferences, giant cells and root gall numbers as indicators of successful or unsuccessful nematode penetration. Harvesting times were highly significant (P ≤ 0.01) on necrotic spot, rootlet interference and root gall numbers in both C. africanus—M. incognita and—M. javanica relations, but were not significant for giant cell number in C. africanus—M. incognita. The results suggested that C. africanus have post-penetration nematode resistance to both Meloidogyne species.

Effects of various hormonally treated substrates on mycelial development, pinning and biomass of Pleurotus ostreatus were investigated. A 3 × 4 experimental layout was used i.e. three substrates: Urochloa panicoides, Zea mays and Datura stramonium and four hormonal treatments: cytokinins; auxins; gibberellins and control. Treatments were replicated three times and arranged in a Completely Randomize Block Design. The results indicated significant differences on mycelial, pinning, fruit caps and biomass (p ≤ 0.05). Mycelial development in respective substrates was as follows: U. panicoides (100%), Z. mays (84.78%) and D. stramonium (36.31%) and pinning rate was 65.48, 32.99, and 12.23% respectively. Hormones also had significant effect on cap size and style length (p ≤ 0.05). Cap sizes were: auxins: 13.42 cm, cytokinins: 9.9 cm and gibberellins: 7.13 cm and style lengths were: 6.93, 8.83 and 11.03 cm respectively. Mushroom biomasses from different substrates were: U. panicoides (7,609.56 g), Z. mays (7,296.42 g) and D. stramonium (4,368.15 g) indicating significant influence of substrate on mushroom biomass.

Dry bean (Phaseolus vulgaris L.) is an important commercialized field crop in South Africa for aiding in food security as a cheap protein source. However, it is highly susceptible to root-knot nematodes (RKN), Meloidogyne species. Use of indigenous nematophagous fungi as bio-control agents (BCA) of Meloidogyne nematodes is a promising research focus area. This is because indigenous fungal species are naturally part of the ecosystem and therefore compatible with other biological processes unlike most synthetic chemicals. The objective of the study was to identify indigenous nematophagous fungal BCA and establish their potential efficacy in reducing M. enterolobii population densities on dry bean with and without incorporation of compost. Screened indigenous fungal species included Aspergillus terreus, Talaromyces minioluteus, T. sayulitensis, Trichoderma ghanense, and T. viride. There were observed significant parasitism differences (P ≤ 0.05) among the BCA, with T. ghanense showing the highest egg parasitism (86%), followed by T. minioluteus (72%) and T. sayulitensis (70%). On the other hand, the highest J2 parasitism was observed on T. minioluteus (95%), followed by A. terreus and T. viride (63%). A similar trend was observed under in vivo conditions, with higher efficacy with compost incorporation. This provides a highly encouraging alternative and ecologically complementary Meloidogyne management in dry bean production.