Preharvest Management Strategies and Their Impact on Mycotoxigenic Fungi and Associated Mycotoxins

Mycotoxigenic fungi that contaminate grain crops can lead to reduced grain quality, crop yield reduction and mycotoxicosis among humans and livestock. Preharvest management of fungi and mycotoxin contamination is considered among the most important mitigating strategies. Approaches include the breeding of resistant cultivars, use of microorganisms chemical control, production practises and the management of plant stressors. Resistant plants provide an effective and environmentally sound strategy to control mycotoxigenic fungi and mycotoxins; and have been documented. Their incorporation into commercial cultivars is, however, slow and complex. Therefore, emphasis should be placed on determining the resistance of cultivars and landraces currently used by producers. Chemical control has been successfully used for wheat; yet little to no research has been done on other important crops. Biological control strategies have focussed on Aspergillus flavus that produces aflatoxins and infects commercially important crops like maize and groundnuts. Commercial biological control products have been developed and field-tested in several African countries with promising results. The impacts of production practises are unclear under variable environmental conditions; but subsequent disease manifestation and mycotoxin contamination can be reduced. Each preharvest approaches contribute to managing mycotoxigenic fungi and their mycotoxins but integrating approaches may provide more effective management of fungal and mycotoxin contamination in crops

Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study

A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4

Studies towards optimising the isolation of diplonine, a neurotoxin isolated from cultures of <i>Stenocarpella maydis</i> (Berk.) Sacc.

Diplonine, a mycotoxin that induces neurotoxic clinical signs in the guinea pig, resembling those occurring in cattle and sheep with diplodiosis, was isolated previously from a Stenocarpella maydisculture. Knowledge of the chemical properties of the toxin, which was characterised as a substituted ß-cyclopropylamino acid, enabled amendments in the present study to the initial steps of the isolation procedure. Extraction with water and fractionation by cation exchange chromatography improved the efficiency of isolation, potentially allowing the preparation of larger amounts of the toxin

Mycotoxigenic Fusarium species associated with grain crops in South Africa – a review

CITATION: Beukes, I., et al. 2017. Mycotoxigenic Fusarium species associated with grain crops in South Africa – a review. South African Journal of Science, 113((3/4), Art. #2016-0121, doi:10.17159/sajs.2017/20160121.The original publication is available at http://sajs.co.zaCereal grains include some of the most important crops grown in South Africa and play a major role in the local economy. Maize, wheat and sorghum are extensively consumed by humans and farm animals, and are also utilised in industrial processes. Grain crops that are grown commercially contribute up to 33% of the country’s total gross agricultural production, whereas subsistence farmers grow grains mainly to sustain their families. In rural communities an average intake of maize grain of more than 300 g dry weight per person per day is not uncommon. The production of grains is often constrained by pests and diseases that may reduce their yields and quality. In South Africa, 33 mycotoxin-producing Fusarium species have been associated with grain crops. Mycotoxins, such as fumonisins and deoxynivalenol, have been found in levels exceeding the maximum levels imposed by the US Food and Drug Administration and the European Union and therefore pose a serious public health concern. We provide an extensive overview of mycotoxigenic Fusarium species associated with grain crops in South Africa, with particular reference to maize, wheat and sorghum.https://www.sajs.co.za/article/view/3660Publisher's versio

Agricultural practices and their potential role in mycotoxin contamination of maize and groundnut subsistence farming

Mycotoxigenic fungi are common pathogens of maize and groundnuts; they produce mycotoxins which reduce the yield and quality of these grain crops. Numerous agricultural practices including crop rotation and storage methods have been shown to impact mycotoxin accumulation. Therefore, the farming and storage practices in maize and groundnut subsistence farming systems in Pongola, Vryheid, Jozini, Manguzi and Mbazwana Districts of northern KwaZulu-Natal (South Africa) were surveyed to determine their potential role in promoting or mitigating mycotoxin contamination. A questionnaire about agricultural farming practices and storage facilities was presented to 65 subsistence maize and/or groundnut farmers. At least 90% of the farmers surveyed were not aware of mycotoxins and their consequences to animal and human health. The majority of the farmers did not practise crop rotation. However, they practised intercropping and sorted damaged and mouldy grain (maize and groundnuts) before storage. The damaged or mouldy grain was largely used as animal feed, thereby exposing animals to an increased risk of mycotoxicoses. Metal tanks and inqolobane (a type of wooden structure) were identified as the most common storage structures. Harvested homegrown maize was mostly used for the farmers’ own consumption but also sometimes sold to the local community. The implementation of mycotoxin awareness campaigns is necessary, particularly in these districts. The storage facilities used by the subsistence farmers allowed increased moisture and insect invasion. The need for the surveillance of mycotoxins in subsistence-farmed food crops is vital. Significance: The main finding of this study is the extent of post-harvest losses and mycotoxin contamination of maize produced by smallholder farmers in South Africa. We further identify methods to manage the risk of mycotoxin exposure to smallholder farmers and their communities as well as reduce post-harvest losses

Diplonine, a neurotoxin isolated from cultures of the fungus Stenocarpella maydis (Berk.) Sacc. that induces Diplodiosis

Diplodiosis is a neuromycotoxicosis of cattle and sheep caused by ingestion of maize infected with the ear-rot fungus Stenocarpella (= Diplodia) maydis. Apart from ataxia, paresis, and paralysis, the toxin is responsible for stillbirths and neonatal losses characterized by the presence of spongiform degeneration in the white matter of the brain in the offspring of dams exposed to infected maize cobs. In the present study a toxin, named diplonine, which induced neurological signs in guinea pigs resembling some of those occurring in cattle and sheep, was isolated from S. maydis cultures. Purification of diplonine was achieved by methanol extraction followed by chromatographic separation on silica gel and RP-18 stationary phases. The structure and relative configuration of diplonine were defined by analysis of NMR and MS data as (S)-2-amino-2-[(1R,2S)-1-hydroxy-2-methylcyclopropyl] acetic acid or the (S)-2-amino-2-[(1S,2R)-diastereomer.The Maize Trust and the Gauteng Department of Agriculture, Conservation and Environment through the Directorate: Technology Development and Support.http://pubs.acs.org/JAF

Diplonine, a Neurotoxin Isolated from Cultures of the Fungus Stenocarpella maydis (Berk.) Sacc. that Induces Diplodiosis

Diplodiosis is a neuromycotoxicosis of cattle and sheep caused by ingestion of maize infected with the ear-rot fungus Stenocarpella (= Diplodia) maydis. Apart from ataxia, paresis, and paralysis, the toxin is responsible for stillbirths and neonatal losses characterized by the presence of spongiform degeneration in the white matter of the brain in the offspring of dams exposed to infected maize cobs. In the present study a toxin, named diplonine, which induced neurological signs in guinea pigs resembling some of those occurring in cattle and sheep, was isolated from S. maydis cultures. Purification of diplonine was achieved by methanol extraction followed by chromatographic separation on silica gel and RP-18 stationary phases. The structure and relative configuration of diplonine were defined by analysis of NMR and MS data as (S)-2-amino-2-[(1R,2S)-1-hydroxy-2-methylcyclopropyl] acetic acid or the (S)-2-amino-2-[(1S,2R)-diastereomer.The Maize Trust and the Gauteng Department of Agriculture, Conservation and Environment through the Directorate: Technology Development and Support.http://pubs.acs.org/JAF