The physico-chemical properties of strawberry tree (Arbutus unedo L.) fruits

The physico-chemical properties of ripe fruits of strawberry tree (Arbutus unedo L.) were determined. The water content, ash, crude fat, proteins, total phenols, sugar, and the content of vitamin C were determined in ripe strawberry tree fruits. Fruits contain 46.7 % of water, 23.5 % of soluble solids, 0.48 % of ash, 118.61 mg/100 g of potassium, 20.63 mg/100 g of sodium, 36.05 mg/100 g of calcium, 9.66 mg/100 g of magnesium, 1.29 mg/100 g of iron, 19.99 mg/100 g of phosphorus, 0.45 mg/100 g of zinc, < 0.99 mg/100 g of manganese, < 0.99 mg/100 g of chromium, < 0.10 mg/100 g of nickel, < 1.32 mg/100 g of lead and < 0.10 mg/100 g of cadmium. Among nutritionally important components found in fruits were: total fat (0.43 %), proteins (0.82 %), fibres (18.5 g/100 g) of which 14.3 g/100g was insoluble and 4.19 g/100 g was soluble fibre, titratable acids (5.1 mg/100 g), glucose (6.2 g/100 g) and fructose (17.2 g/100 g). Ripe fruits contained 271.5 mg/100 g vitamin C, of which 255.3 mg/ 100 g was L-ascorbic acid and 16.2 mg/100 g was dehydroascorbic acid

Phenolic Compounds in Extracts from Eucalyptus globulus Leaves and Calendula officinalis Flowers

Selection of the optimal solvent system for extraction of the phenolics from Eucalyptus globules leaves and Calendula officinalis flowers, determination of the reducing potential and identification of the phenolics in these extracts was performed. The highest content of phenolics was obtained for methanol: water extracts from both sources. All of the Eucalyptus leaf extracts had higher reducing potential than those from the Calendula flowers. Solid-phase purification of the crude extracts removed 57% to 78% of the compounds in the crude extracts. The reducing potential of the purified extracts varied from 0.17 to 2.92 mg caffeic acid/g dry weight. The extracts from Eucalyptus leaves and Calendula flowers both contained chlorogenic acid, rutin and quercetin 3-glucuronide. Ellagic acid derivatives were identified only in the leaves of Eucalyptus, while beside caffeic acid and salicylic acid, quercetin 3-glucuronide, and pinobanksin 3-acetate was found in the Calendula flower extract for the first time.Fil: Dos Santos Ferreira, Cristina Isabel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; ArgentinaFil: Pereyra, A.. University of Ljubljana. Biotechnical Faculty; EsloveniaFil: Patriarca, Andrea Rosana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Mazzobre, Maria Florencia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Polak, T.. University of Ljubljana. Biotechnical Faculty; EsloveniaFil: Abram, V.. University of Ljubljana. Biotechnical Faculty; EsloveniaFil: Buera, Maria del Pilar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Poklar Ulrih, N.. University of Ljubljana. Biotechnical Faculty; Esloveni

Enzymatic Degradation of PrPSc by a Protease Secreted from Aeropyrum pernix K1

BACKGROUND: An R30 fraction from the growth medium of Aeropyrum pernix was analyzed for the protease that can digest the pathological prion protein isoform (PrP(Sc)) from different species (human, bovine, deer and mouse). METHODOLOGY/PRINCIPAL FINDINGS: Degradation of the PrP(Sc) isoform by the R30 fraction and the purified protease was evaluated using the 6H4 anti-PrP monoclonal antibody. Fragments from the N-terminal and C-terminal of PrP(Sc) were also monitored by Western blotting using the EB8 anti-PrP monoclonal antibody, and by dot blotting using the C7/5 anti-PrP monoclonal antibody, respectively. For detection of smaller peptides from incomplete digestion of PrP(Sc), the EB8 monoclonal antibody was used after precipitation with sodium phosphotungstate. Characterization of the purified active protease from the R30 fraction was achieved, through purification by fast protein liquid chromatography, and identification by tandem mass spectrometry the serine metalloprotease pernisine. SDS-PAGE and zymography show the purified pernisine plus its proregion with a molecular weight of ca. 45 kDa, and the mature purified pernisine as ca. 23 kDa. The purified pernisine was active between 58 °C and 99 °C, and between pH 3.5 and 8.0. The temperature and pH optima of the enzymatic activity of the purified pernisine in the presence of 1 mM CaCl(2) were 105 °C ± 0.5 °C and pH 6.5 ± 0.2, respectively. CONCLUSIONS/SIGNIFICANCE: Our study has identified and characterized pernisine as a thermostable serine metalloprotease that is secreted from A. pernix and that can digest the pathological prion protein PrP(Sc)

Simulation of Small Peptide Using Combined Wang-Landau-Transition Matrix Monte Carlo Algorithm

published i

Effects of pH on the stability of cyanidin and cyanidin 3-O-β-glucopyranoside in aqueous solution

The colour variation, colour intensity and stability at various pH values (2.0, 4.0, 7.0 and 9.0) of cyanidin 3-O-β-glucopyranoside (Cy3Glc) and its aglycone cyanidin was investigated during a period of 8 hours storage at 25ºC. Our data showed that pH of aqueous solution had impact on spectroscopic profile of cyanidin and Cy3Glc. Beginning with the most acidic solutions, increasing the pH induce bathochromic shifts of absorbance maximum in the visible range for all examined pH values (with the exception pH 4.0 for cyanidin), while the presence of the 3-glucosidic substitution induce hypsochromic shift. Compared to cyanidin, Cy3Glc has higher colour intensity and higher stability in the whole pH range, except at pH 7.0. The 3-glucosidic substitution influences on the colour intensity of Cy3Glc in the alkaline region. After 8-hour incubation of Cy3Glc and cyanidin at pH 2.0 and 25 ºC, 99% of Cy3Glc and only 27% of cyanidin remained unchanged

Multi-analytical Approach to Oxidative Stability of Unrefined Argan, Chia, Rosa Mosqueta and Olive Oils

Fresh, unrefined argan (AR), chia (CH), rosa mosqueta (RM) and olive (OL) oils were evaluated for thermal stability with dielectric spectroscopy, differential scanning calorimetry, peroxide values (PV) and free fatty acids (FFAs). The dielectric constant (E´), dielectric loss (E´´), and melting temperature (Tm) of the oils correlated with degree of unsaturation, with the highest static dielectric constant (εs´) for CH oil (3.311), the most unsaturated. AR and CHoils showed the highest electrical conductivities at 500 Hz (505, 230 pS/m, respectively), and CH and RM oils the lowest Tm (-41.0, -36.6°C, respectively). All oils stored at 65°C for 432 hr showed minor changes in εs´. After 180°Cfor 28 h, εs´ and ε´´ increased from 5% to 7%. Initial PVs of these oils were <3.7 mmol O2/kg, and for highly unsaturated CH oil this increased to 221 mmol O2/kg after 65°C for 432 hr. At 180°C, the FFAs increased in all oils,except AR oil. Oxidation onset temperature of the oils correlated with PVs after 65°C for 432 h (r=-0.91) and with FFAs and εs´ after 180°C for 28 hr (r=-0.81, -0.83, respectively).Fil: Leiva, Graciela Edith. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Segatin, Natasa. University of Ljubljana; EsloveniaFil: Mazzobre, Maria Florencia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Abramovich, H.. University of Ljubljana; EsloveniaFil: Abram, V.. University of Ljubljana; EsloveniaFil: Vidrih, R.. University of Ljubljana; EsloveniaFil: Buera, Maria del Pilar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Poklar, Ulrih N. University of Ljubljana; Esloveni