Protein Enhancement of Yam (Dioscorea rotundata) Peels with Single-or Co-Inoculation of Aspergillus niger Van Tieghem and Trichoderma viride Pers Ex Fr. Under Solid-State Fermentation

This study assessed the protein enrichment of sterilized and non-sterilised yam peels substrates fermented for 21 days at 25°C with mono- and co-cultures of Aspergillus niger and Trichoderma viride. Yam substrates were harvested at 0, 7, 14, and 21 days intervals for protein content and other chemical composition analyses. Results showed an overall percentage increase in protein contents of sterilised yam peels by 71.80% for A. niger, 58.03% for T. viride, and 80.60% for co-culture of A. niger and T. viride. Protein contents in non-sterilised yam peels increased by 113.30%, 95.00%, and 96.45% for A. niger, T. viride and co-culture of the test fungi, respectively. The significantly (p ≤ 0.05) higher protein contents of the fermented, non-sterilised yam peels suggest possible successional microbial colonization of the substrate, and their combined, cumulative contributions to protein enhancement, unlike the sterilised yam peels. Ash content significantly (p ≤ 0.05) increased in both sterilised and non-sterilised yam peels. These findings underscore the fact that, through fungal bioprocessing, protein contents of yam peels can be significantly enriched for value-addition. The practical implications of the findings are discusse

Microbiological Contamination of some Fresh Leafy Vegetables Sold in Cape Coast, Ghana

This study evaluated the microbiological contamination of cabbage, lettuce, and scallions sold  in Abura and Kotokuraba markets in Cape Coast, Ghana. These vegetables were analyzed for the presence and levels of microorganisms using standard microbiological procedures. Re­sults revealed bacterial and fungal contaminations of the vegetables from Abura and Kotoku­raba markets. Mean bacterial counts recorded in Nutrient Agar, for example, from Kotokuraba market were 1.93x108, 1.23x108, and 1.17x108 cfu/ml for cabbage, lettuce and scallion, respec­tively, higher than mean bacterial counts recorded from Abura market at 9.9x107, 2.8x107, and 6.60x107 cfu/ml for cabbage, lettuce and scallion, respectively. Conversely, the mean fungal counts for cabbage, lettuce and scallion were higher at Abura market than Kotokuraba market. Bacteria isolated from the vegetables include Escherichia coli, Enterobacter spp., Klebsiella spp., Salmonella spp., Serratia marcescens, and Staphylococcus, whereas fungi of the genera Aspergillus, Candida, Fusarium, Penicillium, and Rhodotorula were isolated. These results indicate that the vegetables are significantly contaminated, and have poor microbiological quality that could potentially result in outbreak of foodborne illnesses. Contaminations of the vegetables were due to poor pre- and post-harvest handling practices. The implications of findings of this study on tourism and hospitality industries in Cape Coast are discussed. Keywords: cabbage, food microbiology, foodborne microorganisms, Ghana, lettuce, scallio

The Fastest Flights in Nature: High-Speed Spore Discharge Mechanisms among Fungi

BACKGROUND: A variety of spore discharge processes have evolved among the fungi. Those with the longest ranges are powered by hydrostatic pressure and include "squirt guns" that are most common in the Ascomycota and Zygomycota. In these fungi, fluid-filled stalks that support single spores or spore-filled sporangia, or cells called asci that contain multiple spores, are pressurized by osmosis. Because spores are discharged at such high speeds, most of the information on launch processes from previous studies has been inferred from mathematical models and is subject to a number of errors. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we have used ultra-high-speed video cameras running at maximum frame rates of 250,000 fps to analyze the entire launch process in four species of fungi that grow on the dung of herbivores. For the first time we have direct measurements of launch speeds and empirical estimates of acceleration in these fungi. Launch speeds ranged from 2 to 25 m s(-1) and corresponding accelerations of 20,000 to 180,000 g propelled spores over distances of up to 2.5 meters. In addition, quantitative spectroscopic methods were used to identify the organic and inorganic osmolytes responsible for generating the turgor pressures that drive spore discharge. CONCLUSIONS/SIGNIFICANCE: The new video data allowed us to test different models for the effect of viscous drag and identify errors in the previous approaches to modeling spore motion. The spectroscopic data show that high speed spore discharge mechanisms in fungi are powered by the same levels of turgor pressure that are characteristic of fungal hyphae and do not require any special mechanisms of osmolyte accumulation

A Novel Gene, ROA, Is Required for Normal Morphogenesis and Discharge of Ascospores in Gibberella zeae▿†

Head blight, caused by Gibberella zeae, is a significant disease among cereal crops, including wheat, barley, and rice, due to contamination of grain with mycotoxins. G. zeae is spread by ascospores forcibly discharged from sexual fruiting bodies forming on crop residues. In this study, we characterized a novel gene, ROA, which is required for normal sexual development. Deletion of ROA (Δroa) resulted in an abnormal size and shape of asci and ascospores but did not affect vegetative growth. The Δroa mutation triggered round ascospores and insufficient cell division after spore delimitation. The asci of the Δroa strain discharged fewer ascospores from the perithecia but achieved a greater dispersal distance than those of the wild-type strain. Turgor pressure within the asci was calculated through the analysis of osmolytes in the epiplasmic fluid. Deletion of the ROA gene appeared to increase turgor pressure in the mutant asci. The higher turgor pressure of the Δroa mutant asci and the mutant spore shape contributed to the longer distance dispersal. When the Δroa mutant was outcrossed with a Δmat1-2 mutant, a strain that contains a green fluorescence protein (GFP) marker in place of the MAT1-2 gene, unusual phenotypic segregation occurred. The ratio of GFP to non-GFP segregation was 1:1; however, all eight spores had the same shape. Taken together, the results of this study suggest that ROA plays multiple roles in maintaining the proper morphology and discharge of ascospores in G. zeae