Toxins

7521 KiB

Open AccessReview

Phytotoxins Produced by Fungi Associated with Grapevine Trunk Diseases

by Anna Andolfi, Laura Mugnai, Jordi Luque, Giuseppe Surico, Alessio Cimmino and Antonio Evidente

Toxins 2011, 3(12), 1569-1605; https://doi.org/10.3390/toxins3121569 - 20 Dec 2011

Cited by 168 | Viewed by 16577

Abstract

Up to 60 species of fungi in the Botryosphaeriaceae family, genera Cadophora, Cryptovalsa, Cylindrocarpon, Diatrype, Diatrypella, Eutypa, Eutypella, Fomitiporella, Fomitiporia, Inocutis, Phaeoacremonium and Phaeomoniella have been isolated from decline-affected grapevines all around the World. The main grapevine trunk diseases of mature vines are Eutypa dieback, the esca complex and cankers caused by the Botryospheriaceae, while in young vines the main diseases are Petri and black foot diseases. To understand the mechanism of these decline-associated diseases and the symptoms associated with them, the toxins produced by the pathogens involved in these diseases were isolated and characterised chemically and biologically. So far the toxins of only a small number of these decline fungi have been studied. This paper presents an overview of the toxins produced by the most serious of these vine wood pathogens: Eutypa lata, Phaeomoniella chlamydospora, Phaeoacremonium aleophilum and some taxa in the Botryosphaeriaceae family, and examines how these toxins produce decline symptoms. The chemical structure of these metabolites and in some cases their vivotoxin nature are also discussed. Full article

(This article belongs to the Special Issue Phytotoxins: Chemistry, Bioactivity and Potential Practical Applications)

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482 KiB

Open AccessArticle

Observation of T-2 Toxin and HT-2 Toxin Glucosides from Fusarium sporotrichioides by Liquid Chromatography Coupled to Tandem Mass Spectrometry (LC-MS/MS)

by Mark Busman, Stephen M. Poling and Chris M. Maragos

Toxins 2011, 3(12), 1554-1568; https://doi.org/10.3390/toxins3121554 - 20 Dec 2011

Cited by 75 | Viewed by 9187

Abstract

The trichothecenes produced by solid and liquid cultures of Fusarium sporotrichioides were evaluated with high performance liquid chromatography—tandem mass spectrometry (LC-MS/MS). Along with the expected T-2 toxin HT-2 toxin and neosolaniol, two additional compounds were detected, which had ions 162 m/z higher than those in the mass spectra of T-2 toxin or HT-2 toxin. Fragmentation behavior of these two compounds was similar to that of T-2 toxin and HT-2 toxin. Based on LC-MS/MS behavior, it is proposed that the two compounds are T-2 toxin 3-O-glucoside and HT-2 toxin 3-O-glucoside. Production of the two glucosides was measured in kernels from wheat and oat inoculated with F. sporotrichiodes, as well as in cultures grown in liquid media and on cracked corn or rice. Production of glucosides in wheat and oats suggest that they may also be present in naturally contaminated cereals. Full article

(This article belongs to the Special Issue Trichothecenes)

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946 KiB

Open AccessReview

Current and Future Experimental Strategies for Structural Analysis of Trichothecene Mycotoxins—A Prospectus

by Roxanne A. Shank, Nora A. Foroud, Paul Hazendonk, François Eudes and Barbara A. Blackwell

Toxins 2011, 3(12), 1518-1553; https://doi.org/10.3390/toxins3121518 - 19 Dec 2011

Cited by 37 | Viewed by 9683

Abstract

Fungal toxins, such as those produced by members of the order Hypocreales, have widespread effects on cereal crops, resulting in yield losses and the potential for severe disease and mortality in humans and livestock. Among the most toxic are the trichothecenes. Trichothecenes have various detrimental effects on eukaryotic cells including an interference with protein production and the disruption of nucleic acid synthesis. However, these toxins can have a wide range of toxicity depending on the system. Major differences in the phytotoxicity and cytotoxicity of these mycotoxins are observed for individual members of the class, and variations in toxicity are observed among different species for each individual compound. Furthermore, while diverse toxicological effects are observed throughout the whole cellular system upon trichothecene exposure, the mechanism of toxicity is not well understood. In order to comprehend how these toxins interact with the cell, we must first have an advanced understanding of their structure and dynamics. The structural analysis of trichothecenes was a subject of major interest in the 1980s, and primarily focused on crystallographic and solution-state Nuclear Magnetic Resonance (NMR) spectroscopic studies. Recent advances in structural determination through solution- and solid-state NMR, as well as computation based molecular modeling is leading to a resurgent interest in the structure of these and other mycotoxins, with the focus shifting in the direction of structural dynamics. The purpose of this work is to first provide a brief overview of the structural data available on trichothecenes and a characterization of the methods commonly employed to obtain such information. A summary of the current understanding of the relationship between structure and known function of these compounds is also presented. Finally, a prospectus on the application of new emerging structural methods on these and other related systems is discussed. Full article

(This article belongs to the Special Issue Trichothecenes)

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2084 KiB

Open AccessReview

Pea Albumin 1 Subunit b (PA1b), a Promising Bioinsecticide of Plant Origin

by Frédéric Gressent, Pedro Da Silva, Vanessa Eyraud, Lamis Karaki and Corinne Royer

Toxins 2011, 3(12), 1502-1517; https://doi.org/10.3390/toxins3121502 - 8 Dec 2011

Cited by 49 | Viewed by 9249

Abstract

PA1b (Pea Albumin 1, subunit b) is a peptide extract from pea seeds showing significant insecticidal activity against certain insects, such as cereal weevils (genus Sitophilus), the mosquitoes Culex pipiens and Aedes aegyptii, and certain species of aphids. PA1b has great potential for use on an industrial scale and for use in organic farming: it is extracted from a common plant; it is a peptide (and therefore suitable for transgenic applications); it can withstand many steps of extraction and purification without losing its activity; and it is present in a seed regularly consumed by humans and mammals without any known toxicity or allergenicity. The potential of this peptide to limit pest damage has stimulated research concerning its host range, its mechanism of action, its three-dimensional structure, the natural diversity of PA1b and its structure–function relationships. Full article

(This article belongs to the Special Issue Insecticidal Toxins)

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1277 KiB

Open AccessArticle

Trichothecene Mycotoxins Inhibit Mitochondrial Translation—Implication for the Mechanism of Toxicity

by Mohamed Anwar Bin-Umer, John E. McLaughlin, Debaleena Basu, Susan McCormick and Nilgun E. Tumer

Toxins 2011, 3(12), 1484-1501; https://doi.org/10.3390/toxins3121484 - 2 Dec 2011

Cited by 54 | Viewed by 9962

Abstract

Fusarium head blight (FHB) reduces crop yield and results in contamination of grains with trichothecene mycotoxins. We previously showed that mitochondria play a critical role in the toxicity of a type B trichothecene. Here, we investigated the direct effects of type A and type B trichothecenes on mitochondrial translation and membrane integrity in Saccharomyces cerevisiae. Sensitivity to trichothecenes increased when functional mitochondria were required for growth, and trichothecenes inhibited mitochondrial translation at concentrations, which did not inhibit total translation. In organello translation in isolated mitochondria was inhibited by type A and B trichothecenes, demonstrating that these toxins have a direct effect on mitochondrial translation. In intact yeast cells trichothecenes showed dose-dependent inhibition of mitochondrial membrane potential and reactive oxygen species, but only at doses higher than those affecting mitochondrial translation. These results demonstrate that inhibition of mitochondrial translation is a primary target of trichothecenes and is not secondary to the disruption of mitochondrial membranes. Full article

(This article belongs to the Special Issue Trichothecenes)

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Toxins, Volume 3, Issue 12 (December 2011) – 5 articles , Pages 1484-1605

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