Structural and Gene Characterization of a New Antifungal Peptide Obtained from Penicillium crustosum FP11 Strain

A novel antifungal peptide, PcAFP (6.48 kDa, pI 8.83 ), was obtained from the culture supernatant of the fungus Penicillium crustosum . The gene encoding the PcAFP peptide was isolated b ased on its homologue in Penicillium chrysogenum , PgAFP. PcAFP is a small, cystine-rich peptide, and th e mature peptide consists of 58 amino acid residues. The i mmature P. crustosum antifungal protein (AFP) showed 95.65% identity to the antifungal prote in of P. chrysogenum , while the mature peptide showed 98.28% identity with PgAFP. Molecular modeling of the tertiary structure of the mature peptide revealed details of the conserved stru cture of the AFPs, such as the ? -barrel motif stabilized by three disulfide bonds and the ? -core motif. Analysis of the extract by 16% tricine SD S- PAGE showed a 6.9 kDa peptide, which was close to the pr edicted molecular mass of the mature peptide of 6.48 kDa. Assays of antimicrobial activity , performed by broth microdilution using the crude extract obtained from the culture medium, showe d activity against Candida albicans . These results demonstrate the conservation of the PcAPF gene and the high level of identity with the PgAFP antifungal protein of P. chrysogenum . Given these structural and biochemical characteristics, PcAFP could be a potential candidate for future investigations that may aid in the development of new antifungal compounds.

Enhance of Cellulase Production and Biomass Degradation by Transformation of the Trichoderma reesei RUT-C30∆ zface1 Strain

Abstract The second-generation bioethanol employs lignocellulosic materials degraded by microbial cellulases in their production. The fungus Trichoderma reesei is one of the main microorganisms producing cellulases, and its genetic modification can lead to the optimization in obtaining hydrolytic enzymes. This work carried out the deletion of the sequence that encodes the zinc finger motif of the transcription factor ACE1 (cellulase expression repressor I) of the fungus T. reesei RUT-C30. The transformation of the RUT-C30 lineage was confirmed by amplification of the 989 bp fragment relative to the selection marker, and by the absence of the zinc finger region amplification in mutants, named T. reesei RUT-C30Δzface1. The production of cellulases by mutants was compared to RUT-C30 and measured with substrates carboxymethylcellulose (CMC), microcrystalline cellulose (Avicel®) and Whatman filter paper (PF). The results demonstrated that RUT-C30Δzface1 has cellulolytic activity increased 3.2-fold in Avicel and 2.1-fold in CMC and PF. The mutants presented 1.4-fold higher sugar released in the hydrolysis of the biomass assays. These results suggest that the partial deletion of ace1 gene is an important strategy in achieving bioethanol production on an industrial scale at a competitive price in the fuel market.

High levels of ß-xylosidase in Thermomyces lanuginosus: potential use for saccharification

ABSTRACT A new strain of Thermomyces lanuginosus was isolated from the Atlantic Forest biome, and its β-xylosidases optimization in response to agro-industrial residues was performed. Using statistical approach as a strategy for optimization, the induction of β-xylosidases activity was evaluated in residual corn straw, and improved so that the optimum condition achieved high β-xylosidases activities 1003 U/mL. According our known, this study is the first to show so high levels of β-xylosidases activities induction. In addition, the application of an experimental design with this microorganism to induce β-xylosidases has not been reported until the present work. The optimal conditions for the crude enzyme extract were pH 5.5 and 60 °C showing better thermostability at 55 °C. The saccharification ability of β-xylosidase in the presence of hemicellulose obtained from corn straw raw and xylan from beechwood substrates showed a xylo-oligosaccharide to xylose conversion yield of 80 and 50%, respectively, at 50 °C. Our data strongly indicated that the β-xylosidases activities was not subjected to the effects of potential enzyme inhibitors often produced during fermentation process. These data suggest the application of this enzyme studied for saccharification of hemicellulose, an abundant residue in the American continents, thus providing an interesting alternative for future tests for energy production.

Short-chain fructooligosaccharides do not alter glucose homeostasis but improve the lipid profile in obese rats / Frutooligossacarídeos de cadeia curta na dieta não altera homeostase glicêmica, porém melhora o perfil lipídico em ratos obesos

The present study investigated the effects of short-chain fructooligosaccharides (scFOS) feeding on body weight, fat accumulation, glucose homeostasis and lipid profile in cafeteria (CAF) obese rats. Male Wistar rats were divided randomly into two groups: control group (CTL, n = 10), which received a chow diet and water and CAF (n = 20), which received the cafeteria diet, standard chow and soda. After 30 weeks of diet, 10 animals of CAF group received scFOS in the diet (50 g kg-1 of diet) over a period of 50 days, forming the CAF FOS group. Were evaluated the body weight, fat pad as well as, quantity of feces, glucose tolerance, insulin resistance (IR) and serum lipids levels. Animals submitted to the CAF diet displayed obesity, hyperglycemia, glucose intolerance, hyperinsulinemia and IR. The scFOS feeding not altered obesity, glucose intolerance, hyperinsulinemia and IR. CAF rats also presented hypertriglyceridemia and lower levels of HDL-cholesterol. The CAF FOS animals had reduced serum triglycerides (TG) and increased HDL-cholesterol. Thus, the use of scFOS in the diet can be considered as a hypolipidemic agent in the obese state.

O presente estudo investigou os efeitos da adição de frutooligossacarídeos de cadeia curta (scFOS) sobre o peso corporal, acúmulo de gordura, homeostase glicêmica e perfil lipídico em ratos obesos pela dieta de cafeteria (CAF). Ratos Wistar foram divididos em dois grupos: controle (CTL, n = 10), que receberam dieta padrão e água e CAF, que receberam dieta de CAF, ração padrão e refrigerante (n = 20). Após 30 semanas, dez animais do grupo CAF receberam 50 g kg-1 de dieta de scFOS na ração padrão durante 50 dias, formando o grupo CAF FOS. Foram avaliados o peso corporal e o peso das gorduras, bem como, quantidade de fezes, homeostase glicêmica e concentração de lipídios séricos. Animais do grupo CAF apresentaram obesidade, hiperglicemia, intolerância à glicose, hiperinsulinemia e RI. A adição scFOS não alterou a obesidade, intolerância à glicose, hiperinsulinemia e RI no grupo CAF FOS comparado ao grupo CAF. Animais CAF também apresentaram hipertrigliceridemia e redução na concentração de HDL-colesterol. Os animais CAF FOS apresentaram redução na concentração sérica de triglicerídeos (TG) e aumento no HDL-colesterol. Desta forma, a utilização de scFOS na dieta pode ser considerado como um agente hipolipidêmico nos estados de obesidade.

Copper improves the production of laccase by the white-rot fungus Pleurotus pulmonarius in solid state fermentation

Pleurotus pulmonarius (Fr) Quélet, produced laccase as the main ligninolytic enzyme when cultivated on solid-state cultures using corn cob as substrate. The addition of copper greatly increased the production of enzyme. The addition of 25.0 mM CuSO4 increased the level of laccase from 270 to 1,420 U.L-1 and the fungus showed high resistance to copper under the conditions used in this work.

Pleurotus pulmonarius (Fr) Quélet, um basidiomiceto causador da podridão branca da madeira produz lacase como principal enzima ligninolítica quando cultivado em meio em estado sólido utilizando sabugo de milho como substrato. O íon cobre tem grande efeito na produção da enzima. Os melhores resultados foram obtidos pela adição de 25.0 mM de CuSO4 que causou uma elevação dos níveis enzimáticos de 270 U.L-1 para 1.420 U.L-1 O fungo mostrou uma alta resistência ao íon cobre nas condições de cultivo utilizadas neste trabalho.