Variabilidade de produção de aflatoxinas por linhagens de Aspergillus flavus em diferentes tempos de manutenção

O presente trabalho fui realizado com a finalidade de se estudar a produção de aflatoxinas por linhagens de A. flavus, recém isoladas, em diferentes tempos de manutenção, a fim de contribuir para um melhor entendimento do mecanismo de variação na produção de aflatoxinas. Para isso, foram utilizadas três linhagens de A. flavus produtoras de aflatoxinas, classificadas como: a) grande produtora; b) média produtora e c) baixa produtora. Neste experimento, que se estendeu por 280 dias, os fungos foram estudados em dois métodos de preservação: mantido em óleo mineral, no meio Czapeck, e repicado periodicamente em meio Czapeck modificado. A análise da produção de aflatoxinas foi efetuada de 30 em 30 dias. A quantificação da toxina foi feita por cromatografía em camada delgada, pela técnica de avaliação visual, de diluição até extinção. Foi constatada uma variação na produção de toxina em todas as linhagens, contudo elas não perderam suas características originais.Aflatoxin production by strains recently isolated of Aspergillus flavus was studied, after different storage times understand the mechanisms of possible variations in aflatoxin production. Three A. flavus aflatoxin producing strains were utilized, classified as: a) high producer; b) medium producer and c) low producer. The experiment lasted 280 days and the moulds were studied by two preservation methods: oil covered slants on Czapeck's medium and periodic transfer on Czapeck's modified medium. Quantification of the aflatoxin produced was made at 30 day intervals, on thin-layer chromatography and visual determination by the dilution-to-extinction technique. The production of aflatoxin by all strains varied but they did not lose their initial characteristics. Microscopic examinations revealed thickened zones and hifal enlargements over some globous structures that may be related to aflatoxin production sites

Phanerochaete chrysosporium cellobiohydrolase and cellobiose dehydrogenase transcripts in wood

The transcripts of structurally related cellobiohydrolase genes in Phanerochaete chrysosporium-colonized wood chips were quantified. The transcript patterns obtained were dramatically different from the transcript patterns obtained previously in defined media. Cellobiose dehydrogenase transcripts were also detected, which is consistent with the hypothesis that such transcripts play an important role in cellulose degradation.Articl

Athenian eye cups in context.

Since the late 1970s, scholars have explored Athenian eye cups within the presumed context of the symposion, privileging a hypothetical Athenian viewer and themes of masking and play. Such emphases, however, neglect chronology and distribution, which reveal the complexity of the pottery trade during the late sixth and the fifth centuries B.C.E. Although many eye cups have been found in Athens—namely on the Acropolis and mainly from late in the series—the majority come from funerary, sanctuary, and domestic contexts to the west and east. Most of the earliest, largest, and highest-quality examples were exported to Etruria, where the symposion as the Athenians knew it did not exist. Workshops and traders were clearly aware of their audiences at home and abroad and shifted production and distribution of vases to suit. The Etruscan consumers of eye cups made conscious choices regarding their purchase and use. Tomb assemblages from Vulci and elsewhere reveal their multivalent significance: they are emblematic of banqueting in life and death, apotropaic entities, likely with ritual uses. Rather than being signs of hellenization in a foreign culture, Athenian eye cups—like all Greek vases—were brought into Etruria, then integrated, manipulated, and even transformed to suit local needs and beliefs