RESUMO

Secondary metabolites from fungi have become a major source of chemical innovation in programs searching for lead molecules with bioactivities, especially over the last 50 years. In this review, we discuss the fundamental considerations in the discovery of molecules for agricultural and medicinal uses. This group of organisms possesses a strong potential for scientific and industrial communities. Recently, the incorporation of new technologies for the artificial cultivation of fungi and the use of better equipment to isolate and identify active metabolites has allowed the discovery of leading molecules for the design of new and safer drugs and pesticides. The geographical region including the Patagonian Andes mountains harbors a wide diversity of fungi, many of them still unknown and so far associated with Chilean-Argentinian Andean endemic forests. There have been very few chemical studies of the fungi located in this region. However, those few studies have allowed the discovery of new molecules. We argue that the richness of fungal biodiversity in this region offers an interesting source for the discovery of bioactive molecules for the basic and applied sciences.

Assuntos

RESUMO

The fungal species Fusarium graminearum is related to deoxynivalenol (DON) formation. The aim of this study was to evaluate mycoflora and DON occurrence in 53 whole wheat grain samples collected in Southern Brazil during the 2012 crop. Wheat grains showed adequate values of water activity ranging from 0.48 to 0.72, within the required limits of moisture content, ranging from 9.1% to 13.9%. In addition, low counts of fungal colonies, ranging from 10 to 8.2 × 10(2), were found. For Fusarium genera, there was predominance of Fusarium verticillioides (34%) and F graminearum (30.2%). For Aspergillus species, 37.7% of Aspergillus flavus was determined. Regarding the Penicillium species, Penicillium digitatum (49%) was the most found species. DON was detected in 47.2% (25 out of 53) of the samples analysed, with levels ranging from 243.7 to 2281.3 µg kg(-1) (mean: 641.9 µg kg(-1)).

Assuntos

RESUMO

Based on morphology, fungal species have been considered widespread and as a result names of species from Europe or eastern North America were applied to species in western North America. However, DNA sequences have shown that many western taxa are different from their European counterparts; one such case is presented here. Comparisons of ITS and LSU rDNA sequences from ectomycorrhizal root tips and ascomata of specimens identified as Helvella lacunosa from North America, Europe and Asia revealed that the taxa from western North America and Mexico formed a well supported clade different from the eastern North American, European and Asian taxa. Within this western North American clade there are at least four taxa. Here we describe two of these western taxa as new species: Helvella vespertina and Helvella dryophila. Helvella vespertina is a bigger version of H. lacunosa, is variable in hymenial color and shape and forms ectomycorrhizae with conifers; it fruits typically Oct-Jan. Helvella dryophila is characterized by a dark almost black, squat pileus, a light stipe when young, medium size and forms ectomycorrhizae with Quercus species; it fruits Jan-Jun. Due to insufficient material, the two other Helvella taxa are discussed but not formally described here. We also examined the Hypomyces and other mycoparasites associated with the ascomata of Helvella species and discuss misleadingly labeled sequences in public databases.

Assuntos

RESUMO

The mycoflora of the environment: wheat conditioning, milling and screening, and filling zone, as well as, raw material -wheat-, intermediate product -grits- and end product -flour- on day 1, and after cleaning improvements -days 45 and 90- were studied in an Argentine wheat mill. Samples were incubated at 28°C for 5-7 days on Malt Extract Agar with chloramphenicol (100 mg L-1) and the results were expressed in colony forming units per cubic meter of air (CFU m-3) or per gram of sample (CFU g-1), respectively. Fungal genera and species were isolated and identified and the potential toxicogenic capacity of the Aspergillus flavus and Fusarium graminearum isolated was studied. Time-Place and Time-Product multifactorial ANOVA were carried out. After cleaning improvements, CFU m-3 of air decreased as a function of time. Cladosporium and Alternaria were abundant in every zone, Aspergillus predominated in the wheat conditioning zone and Penicillium and Eurotium decreased with time. Wheat was more contaminated than grits and flour; Aspergillus, Eurotium and Mucoraceae family were the most abundant. Deoxynivalenol was above the levels allowed in wheat, being acceptable in grits and flour. Aflatoxin and Zearalenone showed acceptable levels. When studied in vitro, 53% of Aspergillus flavus and 100% of Fusarium graminearum isolates, produced Total Aflatoxins, and Deoxynivalenol and Zearalenone, respectively.

Assuntos

RESUMO

The mycoflora of the environment: wheat conditioning, milling and screening, and filling zone, as well as, raw material -wheat-, intermediate product -grits- and end product -flour- on day 1, and after cleaning improvements -days 45 and 90- were studied in an Argentine wheat mill. Samples were incubated at 28°C for 5-7 days on Malt Extract Agar with chloramphenicol (100 mg L-1) and the results were expressed in colony forming units per cubic meter of air (CFU m-3) or per gram of sample (CFU g-1), respectively. Fungal genera and species were isolated and identified and the potential toxicogenic capacity of the Aspergillus flavus and Fusarium graminearum isolated was studied. Time-Place and Time-Product multifactorial ANOVA were carried out. After cleaning improvements, CFU m-3 of air decreased as a function of time. Cladosporium and Alternaria were abundant in every zone, Aspergillus predominated in the wheat conditioning zone and Penicillium and Eurotium decreased with time. Wheat was more contaminated than grits and flour; Aspergillus, Eurotium and Mucoraceae family were the most abundant. Deoxynivalenol was above the levels allowed in wheat, being acceptable in grits and flour. Aflatoxin and Zearalenone showed acceptable levels. When studied in vitro, 53% of Aspergillus flavus and 100% of Fusarium graminearum isolates, produced Total Aflatoxins, and Deoxynivalenol and Zearalenone, respectively.(AU)

Assuntos

RESUMO

THE MYCOFLORA OF THE ENVIRONMENT: wheat conditioning, milling and screening, and filling zone, as well as, raw material -wheat-, intermediate product -grits- and end product -flour- on day 1, and after cleaning improvements -days 45 and 90- were studied in an Argentine wheat mill. Samples were incubated at 28°C for 5-7 days on Malt Extract Agar with chloramphenicol (100 mg L(-1)) and the results were expressed in colony forming units per cubic meter of air (CFU m(-3)) or per gram of sample (CFU g(-1)), respectively. Fungal genera and species were isolated and identified and the potential toxicogenic capacity of the Aspergillus flavus and Fusarium graminearum isolated was studied. Time-Place and Time-Product multifactorial ANOVA were carried out. After cleaning improvements, CFU m(-3) of air decreased as a function of time. Cladosporium and Alternaria were abundant in every zone, Aspergillus predominated in the wheat conditioning zone and Penicillium and Eurotium decreased with time. Wheat was more contaminated than grits and flour; Aspergillus, Eurotium and Mucoraceae family were the most abundant. Deoxynivalenol was above the levels allowed in wheat, being acceptable in grits and flour. Aflatoxin and Zearalenone showed acceptable levels. When studied in vitro, 53% of Aspergillus flavus and 100% of Fusarium graminearum isolates, produced Total Aflatoxins, and Deoxynivalenol and Zearalenone, respectively.

RESUMO

Este trabalho objetivou avaliar a qualidade sanitária de 50 lotes comerciais de sementes de braquiária, produzidos em diferentes regiões nas safras de 2004-2005 e 2005-2006. Sementes de Brachiaria brizantha cvs. Marandu e Xaraés, B. decumbens cv. Basilisk, B. humidicola cv. Humidicola e B. ruziziensis cv. Ruziziensis, destinadas ao comércio interno, foram submetidas ao teste de sanidade pelo método de papel de filtro. Adicionalmente, avaliou-se a sanidade de sementes de 'Marandu' (2 lotes) e 'Basilisk' (1 lote) destinadas à exportação. As sementes foram distribuídas sobre papel de filtro acondicionado em gerbox e incubadas a 20º C, com fotoperíodo de 12h, durante sete dias. Os fungos secundários ou de armazenamento (FSA) mais frequentemente detectados nos lotes de braquiária foram Aspergillus sp. e Rhizopus sp. Quanto aos fungos potencialmente patogênicos (FP), constatou-se elevada frequência dos gêneros Bipolaris. Curvularia. Fusarium e Phoma. Em geral, foi elevada a incidência de Bipolaris sp., Fusarium sp. e Phoma sp. nas sementes. A ocorrência de Phoma sp. foi crítica, pois 42% dos lotes registraram índices superiores a 70%. Bipolaris sp., Fusarium sp. e Phoma sp. também foram associados às sementes de braquiária tipo exportação, em alguns casos, com incidência considerável. Os resultados revelaram que as sementes comerciais de braquiária apresentam baixa qualidade sanitária e que, em todas as regiões produtoras, existe pelo menos um fator afetando a sanidade dessas sementes.

This work aimed to evaluate the sanitary quality of 50 commercial lots of seeds of braquiaria grass, produced in different regions in the crop of 2004­2005 and 2005­2006. The lots consisted of seeds of the cultivars Brachiaria brizantha cvs. Marandu and Xaraes, B. decumbens cv. Basilisk, B. humidicola cv. Humidicola and B. ruziziensis cv. Ruziziensis. Additionally, seeds of 'Marandu' (2 lots) and 'Basilisk' (1 lot) for exportation were analyzed. The blotter test was used, at 20º C under alternating light and darkness in a 12h photoperiod, for 7 days. Aspergillus sp. and Rhizopus sp. were the secondary or storage fungi with greatest frequency in lots of seeds. High frequency of potential pathogenic fungi, specifically of the Bipolaris. Curvularia. Fusarium and Phoma genera, was observed. In general, there was a high incidence of Bipolaris sp., Fusarium sp. and Phoma sp. in braquiaria grass seeds. The occurrence of Phoma sp. was severe, because 42% of the lots showed incidence superior to 70%. Bipolaris sp., Fusarium sp. and Phoma sp. were associated to braquiaria grass seeds for exportation, in some cases, with significant incidence. The results evidenced the low sanitary quality of commercial seeds of braquiaria grass, and demonstrated that in all producer regions there is at least one factor affecting the sanitary quality of these seeds.

Assuntos

RESUMO

ABSTRACT This work aimed to evaluate the sanitary quality of 50 commercial lots of seeds of braquiaria grass, produced in different regions in the crop of 20042005 and 20052006. The lots consisted of seeds of the cultivars Brachiaria brizantha cvs. Marandu and Xaraes, B. decumbens cv. Basilisk, B. humidicola cv. Humidicola and B. ruziziensis cv. Ruziziensis. Additionally, seeds of Marandu (2 lots) and Basilisk (1 lot) for exportation were analyzed. The blotter test was used, at 20º C under alternating light and darkness in a 12h photoperiod, for 7 days. Aspergillus sp. and Rhizopus sp. were the secondary or storage fungi with greatest frequency in lots of seeds. High frequency of potential pathogenic fungi, specifically of the Bipolaris. Curvularia. Fusarium and Phoma genera, was observed. In general, there was a high incidence of Bipolaris sp., Fusarium sp. and Phoma sp. in braquiaria grass seeds. The occurrence of Phoma sp. was severe, because 42% of the lots showed incidence superior to 70%. Bipolaris sp., Fusarium sp. and Phoma sp. were associated to braquiaria grass seeds for exportation, in some cases, with significant incidence. The results evidenced the low sanitary quality of commercial seeds of braquiaria grass, and demonstrated that in all producer regions there is at least one factor affecting the sanitary quality of these seeds.

RESUMO Este trabalho objetivou avaliar a qualidade sanitária de 50 lotes comerciais de sementes de braquiária, produzidos em diferentes regiões nas safras de 2004-2005 e 2005-2006. Sementes de Brachiaria brizantha cvs. Marandu e Xaraés, B. decumbens cv. Basilisk, B. humidicola cv. Humidicola e B. ruziziensis cv. Ruziziensis, destinadas ao comércio interno, foram submetidas ao teste de sanidade pelo método de papel de filtro. Adicionalmente, avaliou-se a sanidade de sementes de Marandu (2 lotes) e Basilisk (1 lote) destinadas à exportação. As sementes foram distribuídas sobre papel de filtro acondicionado em gerbox e incubadas a 20º C, com fotoperíodo de 12h, durante sete dias. Os fungos secundários ou de armazenamento (FSA) mais frequentemente detectados nos lotes de braquiária foram Aspergillus sp. e Rhizopus sp. Quanto aos fungos potencialmente patogênicos (FP), constatou-se elevada frequência dos gêneros Bipolaris. Curvularia. Fusarium e Phoma. Em geral, foi elevada a incidência de Bipolaris sp., Fusarium sp. e Phoma sp. nas sementes. A ocorrência de Phoma sp. foi crítica, pois 42% dos lotes registraram índices superiores a 70%. Bipolaris sp., Fusarium sp. e Phoma sp. também foram associados às sementes de braquiária tipo exportação, em alguns casos, com incidência considerável. Os resultados revelaram que as sementes comerciais de braquiária apresentam baixa qualidade sanitária e que, em todas as regiões produtoras, existe pelo menos um fator afetando a sanidade dessas sementes.

RESUMO

Natural mycoflora and co-occurrence of fumonisins (FB(1), FB(2)) and aflatoxins (AFB(1), AFB(2), AFG(1) and AFG(2)) in freshly harvested corn grain samples from four regions of Brazil were investigated. Fusarium verticillioides was predominant in all samples. Analysis of fumonisins showed that 98% of the samples were contaminated with FB(1) and 74.5% with FB(1) + FB(2), with toxin levels ranging from 0.015 to 9.67 microg/g for FB(1) and from 0.015 to 3.16 microg/g for FB(2). Twenty-one (10.5%) samples were contaminated with AFB(1), seven (3.5%) with AFB(2) and only one (0.5%) with AFG(1) and AFG(2) Co-contamination with aflatoxins and fumonisins was observed in 7% of the samples. The highest contamination of fumonisins and aflatoxins was observed in Nova Odessa (SP) and Várzea Grande (MT), respectively. The lowest contamination of these mycotoxins was found in Várzea Grande and Nova Odessa, respectively.

Assuntos

RESUMO

The present study aimed to correlate the mycoflora and mycotoxins production with nitrogen, zinc, and boro levels used during the corn grain crop. For the experiment, following treatments were done: use of four doses of nitrogen (0, 50, 100, and 150 kg/ha), two levels of zinc (0.5 and 1.0 kg/ha), two of boro (0.25 and 0.5 kg/ha), and two l evels of zinc and boro (0.5 and 1.0 , 0.25 and 0.5 kg/ha, respectively). Twenty-five treatments were performed. The corn mycoflora profiles showed that  Aspergillus ,  Penicillium and  Fusarium contaminations prevailed in 42.7, 38.9, and 41.5% of samples, respectively. The highest frequencies of isolated fungal were detected mainly at a w values of 0.53-0.63. Fumonisins analysis indicated a contamination in 100% of corn samples, at concentrations ranging from 1.7 to 27.9 mg/kg for FB 1 , and from 0.3 to 11.2 mg/kg for FB 2 . Seven corn grain samples were contaminated with aflatoxin B 1 at concentrations ranging from 16.0 to 1,858.3 mg/kg, and three samples were contaminated with aflatoxin B 2 at concentrations that ranged from 14.6 to 110.3 mg/kg. Statistical analysis indicated that the nitrogen did influence on the prevalence of  Fusarium spp. in corn grains (p 0.05). A significant negative correlation was observed between nitrogen and the genus  Aspergillus prevalence in corn grains (p 0.10).  

O presente experimento teve como objetivo correlacionar os resultados obtidos da microbiota fúngica e produção de micotoxinas com os níveis de nitrogênio, zinco e boro utilizados no plantio do milho. Foram realizados tratamentos com quatro concentrações de nitrogênio (0, 50, 100 e 150 kg/ha) de forma interativa com duas concentrações de zinco (0,5 e 1,0 kg/ha), duas concentrações de boro (0,25 e 0,5 kg/ ha) e duas concentrações de zinco mais boro (0,5 e 1,0; 0,25 e 0,5 kg/ha respectivamente), perfazendo um total de 25 tratamentos. A média de contaminação das amostras de milho pelos gêneros  Aspergillus, Penicillium e Fusarium  foi de 42,7; 38,9 e 41,5% respectivamente, principalmente na faixa de 0,53 a 0,63 de atividade de água. A análise de fumonisinas revelou uma contaminação em 100% das amostras, em níveis que variaram de 1,7 a 27,9 mg/kg para FB 1 e de 0,3 a 11,2 mg/kg para FB 2 . Foi detectada aflatoxina B 1 em 7 amostras de milho (16,0 a 1858,3   g/kg) e B 2 em 3 amostras (14,6 a 110,3   g/kg). A Análise de Variância demonstrou que o nitrogênio foi positivamente significativo (p 0,05) sobre a porcentagem de contaminação pelo gênero  Fusarium , enquanto que para o gênero  Aspergillus foi negativamente significativo (p 0,10).  

RESUMO

This paper reports a study on the mycobiota in the digestive tract of four important species of triatomines: Rhodnius prolixus, R. neglectus, Diptelanogaster maximus and Panstrongylus megistus. The digestive tracts of 90 adults and 425 nymphs of these four triatomine species were studied and 365 fungal strains were isolated. The genera with the greatest number of species were Aspergillus, Penicillium (14 species in each genus), Acremonium and Cladosporium (three species in each genus), and the most frequent species, in decreasing order, were Aspergillus awamori, Penicillium corylophilum, Cladosporium herbarum and Aspergillus niger. It was concluded that, among the isolated fungi, Aspergillus niger and Penicillium corylophilum might be part of the natural flora of the digestive tract of triatomines.

Um estudo da micobiota do trato digestivo de quatro importantes espécies de triatomíneos, Rhodnius prolixus, R. neglectus, Diptelanogaster maximus e Panstrongylus megistus, foi realizado. Foram examinados os tratos digestivos de 90 adultos e 425 ninfas destas espécies de triatomíneos e 365 cepas fúngicas foram isoladas. Os gêneros com o maior número de espécies encontradas foram Aspergillus, Penicillium (14 espécies cada), Acremonium e Cladosporium (3 espécies cada) e as espécies mais freqüentes, em ordem decrescente, foram Aspergillus awamori, Penicillium corylophilum, Cladosporium herbarum e Aspergillus niger. Dentre os fungos isolados, concluímos que Aspergillus niger e Penicillium corylophilum possam fazer parte da flora natural do trato digestivo destes triatomíneos.