RESUMO
Pineapple (Ananas comosus) is native to South America and widely planted as a fruit crop in the tropics and sub-tropics. This plant is susceptible to a number of fungal diseases of which the most severe is fusariosis. The disease is caused by Fusarium guttiforme and occurs only in South and Central America. The occurrence of a similar disease on pineapples in South Africa has prompted a re-evaluation of the Fusarium sp. associated with pineapple fruit rot. Phylogenetic relationships of isolates from pineapples collected in Brazil and South Africa were assessed based on sequence data for the translation elongation factor-1-α, histone H3 and ß-tubulin gene regions. Analyses showed that the South African isolates represent a species distinct from Brazilian isolates. The South African isolates are characterised by a concentration of aerial mycelium at the centres of the colonies, different to the Brazilian isolates that have an even distribution of aerial mycelium. Both phylogenetic and morphological data show that the disease on pineapple in South Africa is caused by a new Fusarium species described here as F. ananatum sp. nov.
Assuntos
Ananas/microbiologia , Fusarium/classificação , Gibberella/classificação , Doenças das Plantas/microbiologia , Brasil , Frutas/microbiologia , Proteínas Fúngicas/genética , Fusarium/genética , Fusarium/isolamento & purificação , Gibberella/genética , Gibberella/isolamento & purificação , Dados de Sequência Molecular , Fator 1 de Elongação de Peptídeos/genética , Filogenia , África do SulRESUMO
Fumonisins are a family of toxic and carcinogenic mycotoxins produced by Fusarium verticillioides (formerly Fusarium moniliforme), a common fungal contaminant of maize. Fumonisins inhibit ceramide synthase, causing accumulation of bioactive intermediates of sphingolipid metabolism (sphinganine and other sphingoid bases and derivatives) as well as depletion of complex sphingolipids, which interferes with the function of some membrane proteins, including the folate-binding protein (human folate receptor alpha). Fumonisin causes neural tube and craniofacial defects in mouse embryos in culture. Many of these effects are prevented by supplemental folic acid. Recent studies in LMBc mice found that fumonisin exposure in utero increases the frequency of developmental defects and administration of folate or a complex sphingolipid is preventive. High incidences of neural tube defects (NTD) occur in some regions of the world where substantial consumption of fumonisins has been documented or plausibly suggested (Guatemala, South Africa, and China); furthermore, a recent study of NTD in border counties of Texas found a significant association between NTD and consumption of tortillas during the first trimester. Hence, we propose that fumonisins are potential risk factors for NTD, craniofacial anomalies, and other birth defects arising from neural crest cells because of their apparent interference with folate utilization.
Assuntos
Ácido Fólico/metabolismo , Contaminação de Alimentos , Fumonisinas/farmacologia , Defeitos do Tubo Neural/induzido quimicamente , Esfingolipídeos/metabolismo , Zea mays , Animais , Transporte Biológico , Anormalidades Craniofaciais/induzido quimicamente , Técnicas de Cultura , Modelos Animais de Doenças , Humanos , México , Camundongos , Fatores de Risco , TexasRESUMO
In Brazil, the southern region has the highest incidence of esophageal cancer and also the highest production and consumption of corn (Zea mays) products. Corn samples intended for human consumption from the western, northern, and southern regions of the state of Santa Catarina, southern Brazil, had mean total fumonisin B (B(1), B(2), and B(3)) levels of 3.2, 3.4, and 1.7 mg/kg, respectively. Fusarium verticillioides, the predominant fungus in the corn samples, had mean incidences (percent of kernels infected) of 14, 11, and 18% for the three regions, respectively. Additional corn samples intended for animal feed from the southern region had a mean total fumonisin level of 1.5 mg/kg and a mean F. verticillioides incidence of 10%. The fumonisin levels in corn from the state of Santa Catarina, Brazil, were similar to the high levels determined in other high esophageal cancer incidence regions of the world.
Assuntos
Contaminação de Alimentos , Fumonisinas/análise , Fusarium/isolamento & purificação , Zea mays/química , Zea mays/microbiologia , Ração Animal , Animais , Brasil/epidemiologia , Neoplasias Esofágicas/epidemiologia , HumanosRESUMO
The current AOAC International methods for the determination of fumonisins have been validated for corn and cornflakes but have produced low recoveries and high variability when applied to processed corn products for infants. Hence, an investigation was undertaken to improve the extraction efficiency for fumonisins by investigating the use of different extraction solvents. Corn-based infant foods containing cornmeal, corn starch, and corn flour were purchased in the city of Campinas, state of Sao Paulo, Brazil, and were analyzed for fumonisins B1 (FB1), B2 (FB2), and B3 (FB3) following extraction with a range of solvents. Comparison of the results from each of the samples indicated that acidified 70% aqueous methanol at pH 4.0 provided the best overall performance, whereas a methanol/boric acid (pH 9.2) mixture displayed poor extraction efficiency. Extraction with acidified 70% aqueous methanol showed seven of eight test samples to be positive for FB1 (range, 30 to 6,127 microg/kg; relative SD, 4.2 to 51.7%), two of eight samples to be positive for FB2 (range, 53 to 1,738 microg/kg; relative SD, 4.5 to 5.3%), and one of eight samples to be positive for FB3 (575 microg/kg). For samples in which extraction with phosphate-buffered mixtures (pH 3) proved superior, the method suffered from poor chromatography due to interfering compounds. The findings indicate that matrix interferences play a significant role in the extractability, cleanup, and chromatography of the fumonisins.