Short communication - activity of essential oil and phenolic acid extracts of pepperfruit (Dennetia tripetala G. Barker; Anonaceae) against some food-borne microorganisms

A previous report showed that the essential oil and phenolic acid extracts of pepperfruit (Dennetia tripetala ) inhibited the growth of tomato-rot fungi. The study was subsequently extended to other food-borne microorganisms (Staphylococcus aureus , Salmonella sp. Pseudomonas aeruginosa ., Proteus sp., Escherichia coli ., Enterococcus faecalis ., Serratia sp., Bacillus sp., Clostridium sp., Penicillium sp., Aspergillus flavus ) isolated from food products. All the isolates were susceptible to the extracts with a minimum inhibitory concentration (MIC) range of 1.0-4.0 mg/ml. The essential oil inhibited the food-borne organisms better (MIC: 1.0-2.5) than the phenolic acid (MIC: 1.5-4.0). The challenge organisms in fresh, boiled or roasted beef, treated with the extracts were either not detected, declined significantly in number (p<0.05) or did not change significantly in population (p>0.05) after 7 days. A role for pepperfruit extracts in natural food protection is further indicated

Isolamento e seleção de fungos causadores da podridão-branca da madeira em florestas de Eucalyptus spp. com potencial de degradação de cepas e raízes Isolation and screening of wood white rot fungi from Eucalyptus spp. forests with potential for use in degradation of stumps and roots

Este trabalho objetivou isolar fungos causadores da podridão-branca da madeira, a partir de basidiocarpos e de fragmentos de madeira de eucalipto coletados em várias regiões do país, bem como testar seu potencial de degradação de cepas e raízes mortas em plantios comerciais de eucalipto, após o corte raso. Para o isolamento dos fungos foi desenvolvido um meio de cultura de serragem de eucalipto-ágar. Dentre 292 isolados obtidos e submetidos ao teste de Bavendamm, 144 foram classificados como causadores de podridão-branca, capazes de produzir fenoloxidases. Dentre as nove relações C/N testadas, observou-se uma tendência de ocorrer maior degradação de cavacos naquelas iguais a 60 : 1, 200 : 1 e 300 : 1. Utilizando a relação C/N igual a 60 : 1, realizaram-se dois experimentos para avaliar a degradação de cavacos de Eucalyptus saligna por isolados fúngicos de podridão-branca. No primeiro experimento, avaliado aos 90 dias de incubação, foram selecionados sete isolados, que causaram perda de peso em cavacos superior ou igual à causada por Trametes versicolor, usado para comparação. No segundo experimento foram testados 46 isolados fúngicos. Dentre os mais eficientes estavam os sete isolados selecionados no primeiro teste, além de outros quatro isolados. Baseado na análise de DNA, seis isolados foram identificados, sendo três pertencentes à espécie Pycnoporus sanguineus, um ao gênero Peniophora sp., um ao gênero Pestalotiopsis sp. e um ao gênero Ganoderma sp.<br>The aim of this work was to isolate native wood white-rot fungi from fungal fruit-bodies and eucalyptus wood fragments from different regions of Brazil and to test their potential for degrading dead stumps and roots in Eucalyptus plantings after harvest. Fungi isolates were obtained in a culture medium composed by Eucalyptus sawdust and agar. Among 292 isolates submitted to the Banvedamm test, 144 were classified as phenoloxidases producing isolates. Among nine C/N ratios tested, it was observed a tendency of occurring larger chip decay in the C/N ratios equal to 60 : 1, 200 : 1 and 300 : 1. Two decay assays were performed in wood chips of Eucalyptus saligna using the C/N ratio 60 : 1 in order to verify which isolates were able to cause larger reduction of dry matter. In the first assay, which was evaluated at 90 days of incubation, seven isolates that stood out in relation to Trametes versicolor were selected. The second assay evaluated the capacity of 46 isolates in promoting decay. The isolates selected in the first assay were among the 11 most efficient in the second assay. Based on DNA analysis, six isolates were identified as Pycnoporus sanguineus (3 isolates), Peniophora sp., Pestalotiopsis sp. e Ganoderma sp