Optimization and partial purification of beta‑galactosidase production by Aspergillus niger isolated from Brazilian soils using soybean residue

β-Galactosidases are widely used for industrial applications. These enzymes could be used in reactions of lactose hydrolysis and transgalactosylation. The objective of this study was the production, purification, and characterization of an extracellular β-galactosidase from a filamentous fungus, Aspergillus niger. The enzyme production was optimized by a factorial design. Maximal β-galactosidase activity (24.64 U/mL) was found in the system containing 2% of a soybean residue (w/v) at initial pH 7.0, 28 °C, 120 rpm in 7 days. ANOVA of the optimization study indicated that the response data on temperature and pH were significant (p < 0.05). The regression equation indicated that the R2 is 0.973. Ultrafiltration at a 100 and 30 kDa cutoff followed by gel filtration and anion exchange chromatography were carried out to purify the fungal β-galactosidase. SDS-PAGE revealed a protein with molecular weight of approximately 76 kDa. The partially purified enzyme showed an optimum temperature of 50 °C and optimum pH of 5.0, being stable under these conditions for 15 h. The enzyme was exposed to conditions approaching gastric pH and in pepsin’s presence, 80% of activity was preserved after 2 h. These results reveal a A. niger β-galactosidase obtained from residue with favorable characteristics for food industries

Experimental and computational studies of the interactions between carbon nanotubes and ionic liquids used for detection of acetaminophen

The interactions between multi-walled carbon nanotubes and different amounts of an ionic liquid (IL), as well asthe interactions between this system (used as electrochemical sensor) and acetaminophen (ACOP), were in-vestigated through both experimental and theoretical methodologies. Experiments indicated that there is anoptimal concentration of ionic liquid for ACOP detection. A host of techniques and model systems were em-ployed to investigate the adsorption and oxidation processes. To investigate the source of the increased elec-trochemical current in the presence of an IL, we computed the adsorption energy values of ACOP in the nanotube–IL system via Monte Carlo simulations and Density Functional Theory (DFT). DFT allowed us to explore thechanges in adsorption energy due to oxidation. Our theoretical results support the experimentalfindings thatmoderate amounts of IL modulates ACOP/ACOP+adsorption, pointing to a cooperative effect that tends to wanewith increasing amounts of IL pairs. We observed that the IL favors desorption of the oxidized species andfacilitates charge transfer from the ACOP to the nanotube. Therefore, our studies point towards multifactorialeffects with clear physical basis that modulates binding leading to an optimal ratio to promote ACOP detectionThe authors wish to thank the Brazilian research funding institu-tions Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq) and Fundação de Amparo à Pesquisa do Estado de São Paulo(FAPESP) for theirfinancial support (CNPq proc. 400223/2014-7,303596/2014-7, 306177/2016-1, 302801/2014-6, 154089/2016-8,573925/2008-9 and 573548/2008-0; FAPESP 2017/23416-9) andCAPES (Funcap–2133/2012/proc. 23038.007973/2012-90),PRONEM/FUNCAP/CNPq (PNE-0112-00048.01.00/16), PRONEX/FUNCAP (proc. PR2-0101-00030.01.00/15). This study wasfinanced inpart by the Coordenação de Aperfeiçoamento de Pessoal de NívelSuperior–Brasil (CAPES)–Finance Code 00. Camila P. Sousa thanksCAPES- PNPD for her grantinfo:eu-repo/semantics/publishedVersio

第949回千葉医学会例会・第19回千葉大学第三内科懇話会

<p>Accuracy of chlorogenic acid, rutin and isoquercitrin.</p

Density Functional Theory Applied to Excited State Intramolecular Proton Transfer in Imidazole-, Oxazole-, and Thiazole-Based Systems

Excited state intramolecular proton transfer (ESIPT) is a photoinduced process strongly associated to hydrogen bonding within a molecular framework. In this manuscript, we computed potential energy data using Time Dependent Density Functional Theory (TDDFT) for triphenyl-substituted heterocycles, which evidenced an energetically favorable proton transfer on the excited state (i.e., ESIPT) but not on the ground state. Moreover, we describe how changes on heterocyclic functionalities, based on imidazole, oxazole, and thiazole systems, affect the ESIPT process that converts an enolic species to a ketonic one through photon-induced proton transfer. Structural and photophysical data were obtained theoretically by means of density functional theory (DFT) calculations and contrasted for the three heterocyclics. Different functionals were used, but B3LYP was the one that adequately predicted absorption data. It was observed that the intramolecular hydrogen bond is strengthened in the excited state, supporting the occurrence of ESIPT. Finally, it was observed that, with the formation of the excited state, there is a decrease in electronic density at the oxygen atom that acts as proton donor, while there is a substantial increase in the corresponding density at the nitrogen atom that serves as proton acceptor, thus, indicating that proton transfer is indeed favored after photon absorption

Extracts of Morus nigra L. Leaves Standardized in Chlorogenic Acid, Rutin and Isoquercitrin: Tyrosinase Inhibition and Cytotoxicity.

Melanogenesis is a process responsible for melanin production, which is stored in melanocytes containing tyrosinase. Inhibition of this enzyme is a target in the cosmetics industry, since it controls undesirable skin conditions such as hyperpigmentation due to the overproduction of melanin. Species of the Morus genus are known for the beneficial uses offered in different parts of its plants, including tyrosinase inhibition. Thus, this project aimed to study the inhibitory activity of tyrosinase by extracts from Morus nigra leaves as well as the characterization of its chromatographic profile and cytotoxicity in order to become a new therapeutic option from a natural source. M. nigra leaves were collected, pulverized, equally divided into five batches and the standardized extract was obtained by passive maceration. There was no significant difference between batches for total solids content, yield and moisture content, which shows good reproducibility of the extraction process. Tyrosinase enzymatic activity was determined for each batch, providing the percentage of enzyme inhibition and IC50 values obtained by constructing dose-response curves and compared to kojic acid, a well-known tyrosinase inhibitor. High inhibition of tyrosinase activity was observed (above 90% at 15.625 μg/mL). The obtained IC50 values ranged from 5.00 μg/mL ± 0.23 to 8.49 μg/mL ± 0.59 and were compared to kojic acid (3.37 μg/mL ± 0.65). High Performance Liquid Chromatography analysis revealed the presence of chlorogenic acid, rutin and, its major compound, isoquercitrin. The chromatographic method employed was validated according to ICH guidelines and the extract was standardized using these polyphenols as markers. Cytotoxicity, assessed by MTT assay, was not observed on murine melanomas, human keratinocytes and mouse fibroblasts in tyrosinase IC50 values. This study demonstrated the potential of M. nigra leaf extract as a promising whitening agent of natural source against skin hyperpigmentation

Carcinoma verrucoso: uma variante clínico-histopatológica do carcinoma espinocelular Verrucous carcinoma: a clinical-histopathologic variant of squamous cell carcinoma

O carcinoma verrucoso é uma rara e indolente forma do carcinoma espinocelular descrita por Ackerman em 1948. Sua localização preferencial é a cavidade oral. Clinicamente manifesta-se como lesão verrucosa, de progressivo e lento crescimento e bom prognóstico. O tratamento de escolha é a exérese cirúrgica, devendo o paciente ser regularmente acompanhado devido ao risco de recorrências.<br>Verrucous carcinoma is a rare and indolent variant of the squamous cell carcinoma described by Ackerman in 1948. The oral cavity is a most common site. Clinically, it presents most often as a slow-growing verrucous lesion. The prognosis is good. Treatment of choice is surgery. Patients require frequent reevaluation because recurrences may occur

Robustness of chlorogenic acid, rutin and isoquercitrin.

<p>Robustness of chlorogenic acid, rutin and isoquercitrin.</p

HPLC chromatogram of standardized extract of <i>M</i>. <i>nigra</i> leaves (2 mg/mL).

<p>(A) Batch 1. (B) Batch 2. (C) Batch 3. (D) Batch 4. (E) Batch 5.</p