RESUMO
We developed a novel one-pot strategy for synthesizing biologically important 1,2,4-triazole motifs from easily accessible 4-hydroxy phenylacetic acid, formamidine hydrochloride and hydrazine derivatives under mild conditions. This strategy enabled us to synthesize the natural penipanoid A and its analogues in one step.
RESUMO
Methanolic extracts of four cultivated edible mushrooms of Pleurotus spp. namely Pleurotus florida, Pleurotus sajor-caju, Pleurotus cystidiosus and Pleurotus djamor along with the sporeless/low sporing mutants of Pleurotus florida, and Pleurotus sajor-caju were analyzed for their antioxidant activity using different chemical assays. The electrochemical behaviors of these extracts were also analyzed using cyclic voltammetry and differential pulse voltammetry. Results showed that scavenging effects on 2,2-diphenyl-1-picrylhydrazyl radicals were good (73.3-42.4 %) at 1.5 mg/ml. At 12 mg/ml, the reducing powers (2.54-1.71) and chelating effects on ferrous ions (56.0-78.5 %) were excellent. H2O2 scavenging abilities at 1.5 mg/ml showed a wide range (20.0-85.4 %). Scavenging of superoxide radicals were excellent and were found to be in the range of 61.1-90.0 % at 16 mg/ml concentration. FRAP results were in the range of 1.20 - 0.98 at 16 mg/ml. Total phenolic and total flavonoid contents of the methanolic extracts ranged from 22.67 to 36.03 mg/g and 1.19-2.94 µg/g respectively. The study assessed the amount of variation in antioxidant activities exhibited by different cultivated species and their sporeless/low sporing mutants.
RESUMO
Methanolic extracts of cap and stipe of commercially obtained mushrooms Agaricus bisporus, Hypsizygus ulmarius, and Calocybe indica were analyzed for their antioxidant activity in different chemical systems including reducing power, free radical scavenging, ferric reducing antioxidant power (FRAP), superoxide scavenging, peroxide scavenging, metal chelating activities and electrochemical behavior. Scavenging effects on 2,2-diphenyl-1-picrylhydrazyl radicals were moderate (43.5-59.0%) at 1.5 mg/ml. Chelating effects on ferrous ions were moderate to excellent (40.6-96.1%) at 20 mg/ml. At 12 mg/ml, the reducing powers were excellent (2.54-1.71). FRAP results were in the range 2.15-0.98 at 16 mg/ml. The ability to scavenge H2O2 was moderate to excellent (48.9-97.7%) at 1.5 mg/ml. At 10 mg/ml, Agaricus bisporus cap proved to be better at scavenging superoxide radicals than others. Similar electrochemical responses of all extracts suggested similar electroactive chemical composition. The total phenols in the extracts ranged from 14.73-26.72 mg/g.The total flavonoid content ranged from 1.12-2.17 µg/g.
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This study presents the synthesis of zirconia/multi-walled carbon nanotube (ZrO2/MWCNTs) hybrid as a novel sorbent for water defluoridation. The synthesis was facilitated by the high degree of functionalization of MWCNTs using a microwave assisted process. In the final product, nearly 3% of the carbon atoms were attached to ZrO2. The ZrO2/MWCNTs were effective in fluoride removal and mechanistic aspects of the process are presented. The research findings highlight the potential application for the use of MWCNT hybrids in environmental remediation.
Assuntos
Fluoretos/isolamento & purificação , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Água/química , Zircônio/química , Absorção , Fluoretos/química , Teste de Materiais , Tamanho da PartículaRESUMO
Nanosecond laser pulses (lambda = 355 nm) were used to cut mechanosensory neurons in Caenorhabditis elegans and motorneurons in Drosophila melanogaster larvae. A pulse energy range of 0.8-1.2 microJ and < 20 pulses in single shot mode were sufficient to generate axonal cuts. Viability post-surgery was >95% for C. elegans and 60% for Drosophila. Cavitation bubble dynamics generated due to laser-induced plasma formation were observed in vivo by time-resolved imaging in both organisms. Bubble oscillations were severely damped in vivo and cavitation dynamics were complete within 100 ns in C. elegans and 800 ns in Drosophila. We report the use of this system to study axonal transport for the first time and discuss advantages of nanosecond lasers compared to femtosecond sources for such procedures.
Assuntos
Axotomia/instrumentação , Terapia a Laser/instrumentação , Microcirurgia/instrumentação , Nanotecnologia/instrumentação , Vesículas Sinápticas/fisiologia , Vesículas Sinápticas/ultraestrutura , Transporte Biológico Ativo/fisiologia , Desenho de Equipamento , Análise de Falha de Equipamento , Nanotecnologia/métodosRESUMO
A simple fluorescent detection based on the ligand exchange mechanism is proposed for the fluoride ion in aqueous media. This procedure is based on the exchange of 8-hydroxyquinoline (oxine) coordinated to Zr(IV) by fluoride ion without interference from other common anions. The ternary complex of oxine with [Zr(H(2)O)(2)EDTA].2H(2)O formed by replacing two water molecules in aqueous solution provides a sensitive signalling system for fluoride ion in the concentration range from 6 x 10(-7)M to 8 x 10(-4)M. The green fluorescence (lambda(max)=532 nm) exhibited by the complex upon excitation at 247 nm decreases in intensity with fluoride addition with a detection limit of 12 ppb. The complexation reaction between oxine and Zr(IV)-EDTA and the ligand exchange reaction with fluoride ion has been investigated by UV-vis and fluorescence spectroscopies combined with the PM3 semi-empirical quantum chemical calculations. Job's method of continuous variation and the molar ratio method ascertain a 1:1 stoichiometry composition of the chelate in aqueous media.
Assuntos
Fluoretos/análise , Compostos Organometálicos/química , Quinolinas/química , Espectrometria de Fluorescência/métodos , Íons/análise , Oxiquinolina/químicaRESUMO
Database of Databases (DoD) is a collection of molecular biology databases extracted from Nucleic Acids Research, 2005 Database issue. DoD is constructed using javascript and html code. The 14 categories of 719 databases are provided with a search option, keyword help and database description linked to respective pages. Keyword help lists the search strings used to perform an individual search against categorized databases. Database description provides brief information about the database with a link to full-text article and main web page. DoD is available online and can be accessed at http://www.progenebio.in/DoD/DoD.htm.