Abstract The transposable elements are known by their ability to move and integrate into the genome of the host organism. They are classified in retrotransposons class I, which has, as intermediate of the transposition, the RNA and retrotransposons class II, which is composed of the DNA transposons, whose DNA migrates directly or is copied and inserted into the genome. The retrotransposable element Rex1 is a non-LTR retrotransposon found in several types of organisms. Many studies indicate that the Rex retrotransposons have the capacity to respond to environmental stress. The results found in this study corroborate the hypothesis that this retrotransposon possesses a response to environmental stress, since the chromosomal mapping, obtained through FISH, showed a higher number of markings on animals that were submitted to stress in 48h by the copper sulfate action. Furthermore, we can identify an increase in heterochromatic regions in the chromosomes. In the absolute quantification by Real-Time PCR, we found the largest numbers of Rex1 copies in the samples that were submitted to environmental stress by copper sulfate.

We evaluated the biomass of twenty Amazonian fungal isolates as a potential source of mycelium-bound lipases with hydrolytic, synthetic or enantioselective activity for biocatalysis application. We compared the hydrolytic activity of three biomass treatments (delipidated, non-delipidated and cultivated in medium without inducer). Delipidated biomass showed better results in the hydrolysis of p-nitrophenyl palmitate compared to the other two treatments for fifteen isolates. Delipidated biomass of six Aspergillus strains and UEA_115 strain showed a high synthesis activity of ethyl palmitate by transesterification in organic medium. Results were confirmed by spectrophotometry (410 nm) and gas chromatography. In this reaction, the isolate DPUA_1539 A. flavo-furcatis reached a maximum value of 668.5 ± 23.5 mU g-1. Enantioselective activity assays indicated that biomass-bound lipases from UEA_115 isolate (E = 3.58; ees = 7 ± 0) and in particular from the DPUA_1539 A. flavo-furcatis isolate (E = 24.15; ees = 91 ± 1) have the ability to discriminate enantiomers of the drug ibuprofen by ester synthesis, preferably with (R)-enantiomer. These results encourage further investigations of these fungi as potential lipase suppliers for biocatalytic processes such as biodiesel production and enantiopure drugs.

A survey of Microsporum gypseum was conducted in soil samples in different geographical regions of Brazil. The isolation of dermatophyte from soil samples was performed by hair baiting technique and the species were identified by morphology studies. We analyzed 692 soil samples and the recuperating rate was 19.2%. The activities of keratinase and elastase were quantitatively performed in 138 samples. The sequencing of the ITS region of rDNA was performed in representatives samples. M. gypseum isolates showed significant quantitative differences in the expression of both keratinase and elastase, but no significant correlation was observed between these enzymes. The sequencing of the representative samples revealed the presence of two teleomorphic species of M. gypseum (Arthroderma gypseum and A. incurvatum). The enzymatic activities may play an important role in the pathogenicity and a probable adaptation of this fungus to the animal parasitism. Using the phenotypical and molecular analysis, the Microsporum identification and their teleomorphic states will provide a useful and reliable identification system.