This work studied the immobilization of Cercospora kikuchii lipases on chitosan microparticles by chemical attachment on chitosan acetate microparticles activated by glutaraldehyde (CAM) added before or after the enzyme and physical adsorption on highly deacetylated chitosan hydrochloride microparticles (CHM). Lipases covalently immobilized on pre-activated CAM showed better performance retaining 88.4% of the enzymatic activity, with 68.2% of immobilization efficiency (IE). The immobilized enzyme retained an activity of about 53.5 % after five reuses, using p-NPP as substrate. Physical adsorption of lipase onto highly deacetylated CHM showed 46.2 % of enzymatic activity and 28.6% of IE. This immobilized derivative did not lose activity up to 80 days of storage at 4°C, while lipases immobilized on pre-activated CAM maintained its activity up to 180 days at same conditions. Taken together the results indicate that chitosan microparticles provide an optimal microenvironment for the immobilized enzyme to maintain good activity and stability.

Mesmo havendo grandes investimentos, a resistência a fármacos continua sendo um grave problema de saúde pública. Produtos naturais têm prevalecido como a maior fonte de novas drogas e muitos deles são isolados de sistemas simbióticos: microorganismos-plantas. Os fungos endofíticos Papulaspora immersa e Arthrinium state of Apiospora montagnei Sacc. foram isolados de raízes de Smallanthus sonchifolius (yacón). Extratos de culturas destes fungos apresentaram atividade antibacteriana frente Staphylococcus aureus, Kocuria rhizophila, Pseudomonas aeruginosa e Escherichia coli, sendo as mais relevantes observadas nas frações acetato de etila provenientes dos fungos P. immersa e Arthrinium state of Apiospora montagnei Sacc. frente a P. aeruginosa, apresentando CIM de 90µg/mL e 160µg/mL, respectivamente.

Papulaspora immersa and Arthrinium state of Apiospora montagnei Sacc. were isolated from the roots of Smallanthus sonchifolius (yacón). The crude extracts from their cultures inhibited the growth of Staphylococcus aureus, Kocuria rhizophila, Pseudomonas aeruginosa and Escherichia coli. The more relevant results were observed in the ethyl acetate extract from P immersa against P aeruginosa (90 µg/mL) and ethyl acetate extract from Arthrinium state of A montagnei Sacc. against P aeruginosa (160 µg/mL). The two endophytic fungi isolated from yacón roots as well as their antimicrobial activity detected in the crude extracts cultures were being reported for the first time.

A biotransformação da lignana tetraidrofurânica, (-)-grandisina, pelo fungo endofítico Phomopsis sp, obtido de Viguiera arenaria, conduziu à formação de um novo metabólito caracterizado como 3,4-dimetil-2-(4'-hidróxi-3',5'-dimetóxifenil)-5-metóxi-tetraidrofurano. O metabólito foi analisado contra o parasita Trypanosoma cruzi, o agente causador da doença de Chagas, e mostrou uma atividade tripanocida (IC50 9,8 μmol L-1) similar ao precursor natural (IC50 3,7 μmol L-1).

The biotrasformation of the tetrahydrofuran lignan, (-)-grandisin, by the endophitic fungus Phomopsis sp, obtained from Viguiera arenaria, led to the formation of a new compound determined as 3,4-dimethyl-2-(4'-hydroxy-3',5'-dimethoxyphenyl)-5-methoxy-tetrahydrofuran. The metabolite was evaluated against the parasite Trypanosoma cruzi, the causative agent of Chagas's disease, and showed a trypanocidal activity (IC50 9.8 μmol L-1) similar to the natural precursor (IC50 3.7 μmol L-1).

Os efeitos de compostos benzênicos de plantas, respectivamente ácido cinâmico, ácido coumárico, ácido ferúlico, ácido cafeico e aldeído cinâmico, sobre o crescimento da colônia e a morfologia das hifas de Neurospora crassa foram investigados. Ácido cinâmico, ácido ferúlico e aldeído cinâmico inibiram o crescimento colonial, mas não produziram diferenças visíveis sobre as hifas. Ácido cafeico e ácido coumárico não inibiram o crescimento, mas alteraram a morfologia das hifas. Os resultados sugerem que os ácidos cafeico e coumárico afetam provavelmente a manutenção da polaridade (a contínua deposição de material da parede na ponta em extensão), enquanto aldeído cinâmico e os ácidos cinâmicos e ferúlico diminuem a velocidade de crescimento, mas não alteram a polaridade das hifas. Actina no citoesqueleto e no Spitzenkörper apareceu difuso e não estava claramente visível na presença de um dos compostos benzênicos na cultura.

The effects of the benzene compounds from plants, respectively cinnamic acid, coumaric acid, ferulic acid, caffeic acid, and cinnamic aldehyde on growth and hyphal morphology of Neurospora crassa, were investigated. Cinnamic acid, ferulic acid and cinnamic aldehyde inhibited colony growth, but produced no visible alterations on hyphae. Caffeic acid and coumaric acid did not inhibit growth, but changed hyphal morphology. The results suggest that caffeic and coumaric acids probably affect polarity maintenance (the continued deposition of wall material at the extending tip), while cinnamic aldehyde, ferulic and cinnamic acids decrease growth rate, but did not change hyphal polarity. The actin cytoskeleton and the Spitzenkörper appeared diffuse and not clearly visible when one of the benzene compounds was present in the culture.

Estudos prévios realizados em nosso laboratório demonstraram que o fungo Penicillium frequentans produz altos níveis de poligalacturonase e pectinesterase. Endopoligalacturonase I (Endo-PG I) e Exopoligalacturonase I (Exo-PG I) já foram previamente purificadas e caracterizadas. No presente trabalho foram separadas, purificadas parcialmente e caracterizadas bioquimicamente duas poligalacturonases extracelulares. Ambas foram caracterizadas como exopoligalacturonases e então foram designadas exopoligalacturonase II (Exo-PG II) e exopoligalacturonase III (Exo-PG III) as quais apresentaram massa molecular de 63 kDa (Exo-PG II) e 79 kDa (Exo-PG III). Os valores de Km foram 1,6 e 0,059 g/L e os de Vmáx = 2571 e 185 U/mg, respectivamente. A temperatura ótima de ambas foi 50ºC e enquanto o pH ótimo da Exo-PG II foi 5,0 o da Exo-PG III foi 5,8.

Previous studies from our laboratory have demonstrated that the fungus Penicillium frequentans produces high levels of polygalacturonase and pectinesterase. Endopolygalacturonase I (Endo-PG I) and Exopolygalacturonase I (Exo-PG I) were previously purified and characterized. In the present study two extracellular polygalacturonases were separated, partially purified and biochemically characterized. Both were characterized as exopolygalacturonases so they were named exopolygalacturonase II (Exo-PG II) and exopolygalacturonase III (Exo-PG III) which had a molecular mass of 63 kDa (Exo-PG II) and 79 kDa (Exo-PG III). The Km values were 1.6 and 0.059 g/L and the Vmax values were 2571 and 185 U/mg, respectively. The optimum temperature was 50ºC for both enzymes, while the optimum pH was 5.0 for Exo-PG II and 5.8 for Exo-PG III.