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1.
Braz J Microbiol ; 45(1): 294-302, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24948948

RESUMO

Lipases produced by a newly isolated Sporidiobolus pararoseus strain have potential catalytic ability for esterification reactions. After production, the enzymatic extracts (conventional crude and precipitated, 'CC' and 'CP', and industrial crude and precipitated, 'IC' e 'IP') were partially characterized. The enzymes presented, in general, higher specificity for short chain alcohols and fatty acids. The precipitated extract showed a good thermal stability, higher than that for crude enzymatic extracts. The 'CC' and 'CP' enzymes presented high activities after exposure to pH 6.5 and 40 °C. On the other hand, the 'IC' and 'IP' extracts kept their activities in a wide range of pH memory but presented preference for higher reaction temperatures. Preliminary studies of application of the crude lipase extract in the enzymatic production of geranyl propionate using geraniol and propionic acid as substrates in solvent-free system led to a reaction conversion of 42 ± 1.5%.


Assuntos
Basidiomycota/enzimologia , Lipase/isolamento & purificação , Lipase/metabolismo , Álcoois/metabolismo , Basidiomycota/crescimento & desenvolvimento , Estabilidade Enzimática , Ácidos Graxos/metabolismo , Concentração de Íons de Hidrogênio , Lipase/química , Especificidade por Substrato , Temperatura
2.
Langmuir ; 30(15): 4301-9, 2014 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-24605942

RESUMO

Graphite microparticles (d50 6.20 µm) were oxidized by strong acids, and the resultant graphite oxide was thermally exfoliated to graphene oxide sheets (MPGO, C/O 1.53). Graphene oxide was treated with nonthermal plasma under a SO2 atmosphere at room temperature. The XPS spectrum showed that SO2 was inserted only as the oxidized intermediate at 168.7 eV in the S 2p region. Short thermal shocks at 600 and 400 °C, under an Ar atmosphere, produced reduced sulfur and carbon dioxide as shown by the XPS spectrum and TGA analysis coupled to FTIR. MPGO was also submitted to thermal reaction with SO2 at 630 °C, and the XPS spectrum in the S 2p region at 164.0 eV showed that this time only the nonoxidized episulfide intermediate was inserted. Plasma and thermal treatment produced a partial reduction of MPGO. The sequence of thermal reaction followed by plasma treatment inserted both sulfur intermediates. Because oxidized and nonoxidized intermediates have different reactivities, this selective insertion would allow the addition of selective types of organic fragments to the surface of graphene oxide.

3.
Braz. j. microbiol ; 45(1): 294-301, 2014. ilus, tab
Artigo em Inglês | LILACS | ID: lil-709490

RESUMO

Lipases produced by a newly isolated Sporidiobolus pararoseus strain have potential catalytic ability for esterification reactions. After production, the enzymatic extracts (conventional crude and precipitated, 'CC' and 'CP', and industrial crude and precipitated, 'IC' e 'IP') were partially characterized. The enzymes presented, in general, higher specificity for short chain alcohols and fatty acids. The precipitated extract showed a good thermal stability, higher than that for crude enzymatic extracts. The 'CC' and 'CP' enzymes presented high activities after exposure to pH 6.5 and 40 ºC. On the other hand, the 'IC' and 'IP' extracts kept their activities in a wide range of pH memory but presented preference for higher reaction temperatures. Preliminary studies of application of the crude lipase extract in the enzymatic production of geranyl propionate using geraniol and propionic acid as substrates in solvent-free system led to a reaction conversion of 42 ± 1.5%.


Assuntos
Basidiomycota/enzimologia , Lipase/isolamento & purificação , Lipase/metabolismo , Álcoois/metabolismo , Basidiomycota/crescimento & desenvolvimento , Estabilidade Enzimática , Ácidos Graxos/metabolismo , Concentração de Íons de Hidrogênio , Lipase/química , Especificidade por Substrato , Temperatura
4.
Braz. j. microbiol ; 43(4): 1490-1498, Oct.-Dec. 2012. ilus, graf, tab
Artigo em Inglês | LILACS | ID: lil-665836

RESUMO

The lipase produced by a newly isolate Sporidiobolus pararoseus strain has potential catalysis ability for esterification reactions. In order to improve its synthetic activity, this work aimed at optimizing 'synthetic lipase' production by submerged fermentation of a conventional media based on peptone, yeast extract, NaCl and olive oil using experimental design technique. According to the results obtained in the first experimental design (2(4-1)), yeast extract and NaCl concentrations were tested to further optimization by response surface methodology. The maximum 'synthetic lipase' activity obtained was 26.9 U/mL in the optimized media (5.0, 6.8, 7.0 and 1.0% (wt/v) of peptone, yeast extract, NaCl and olive oil, respectively), representing a 6.36-fold increase compared to the initial medium. The time course of 'synthetic lipase' production in the optimized condition was evaluated in terms of synthetic activity, protease activity, biomass and total carbon and the maximum synthetic activity was observed during the stationary phase of growth.


Assuntos
Sequência de Bases , Blastomyces/isolamento & purificação , Fermentação , Fungos Mitospóricos/genética , Fungos Mitospóricos/isolamento & purificação , Leveduras/isolamento & purificação , Lipase/análise , Lipase/isolamento & purificação , Ativação Enzimática , Microbiologia Industrial , Metodologia
5.
Braz J Microbiol ; 43(4): 1490-8, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24031980

RESUMO

The lipase produced by a newly isolate Sporidiobolus pararoseus strain has potential catalysis ability for esterification reactions. In order to improve its synthetic activity, this work aimed at optimizing 'synthetic lipase' production by submerged fermentation of a conventional media based on peptone, yeast extract, NaCl and olive oil using experimental design technique. According to the results obtained in the first experimental design (2(4-1)), yeast extract and NaCl concentrations were tested to further optimization by response surface methodology. The maximum 'synthetic lipase' activity obtained was 26.9 U/mL in the optimized media (5.0, 6.8, 7.0 and 1.0% (wt/v) of peptone, yeast extract, NaCl and olive oil, respectively), representing a 6.36-fold increase compared to the initial medium. The time course of 'synthetic lipase' production in the optimized condition was evaluated in terms of synthetic activity, protease activity, biomass and total carbon and the maximum synthetic activity was observed during the stationary phase of growth.

6.
Environ Technol ; 31(4): 365-71, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20450110

RESUMO

A sequential experimental design strategy is used to optimize the extraction of lead from slag. The slag is composed mainly of iron (= 60%) and lead (= 6%), and cannot be disposed of in conventional landfill due to its high lead content. The extraction of lead is based on the complexing properties of ethylenediaminetetra-acetic acid (EDTA), the iron being masked with fluoride ions. Atomic absorption spectroscopy (AAS) has been used for monitoring iron and lead concentrations. In a first step, Plackett-Burman PB-12 experimental design was used for screening the variables and for selecting those to be used. Two central composite designs (CCDs) were then carried out to determine the optimal conditions for lead extraction. The optimized experimental conditions were established to be: contact time with the fluoride solution 30 min; particle size of slag between 150 and 600 microm; molecular concentration of fluoride solution 2.4 x 10(-3) mol and of EDTA 5 x 10(-4) mol; pH 1.5; 8 h contact time with the EDTA solution; and temperature 60 degrees C. Under these experimental conditions the lead content was reduced by 57% compared with the raw sample.


Assuntos
Quelantes/química , Ácido Edético/química , Resíduos Industriais , Chumbo/isolamento & purificação , Gerenciamento de Resíduos/métodos , Concentração de Íons de Hidrogênio
7.
Clin Breast Cancer ; 10(3): 238-45, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20497923

RESUMO

INTRODUCTION: Analysis of nipple aspirate fluid (NAF) allows the noninvasive identification of both cellular and biomolecular markers of human breast cancer, the most common female malignancy in developed countries. Cytosolic superoxide dismutase (SOD-1) represents a detoxifying enzyme able to regulate the balance between oncogenic and oncosuppressor reactive oxygen species. PATIENTS AND METHODS: We analyzed SOD-1 expression in 126 NAF samples collected from 67 women with and 59 without breast cancer, using enzyme-linked immunosorbent assay, immunoprecipitation, Western blotting, and immunocytochemistry. RESULTS: SOD-1 median values in plasma presented no difference between the no-cancer and cancer subgroups. No significant difference in the median level of SOD-1 between matched plasma and NAF from cancer patients was found, whereas SOD-1 median level in no-cancer NAF was significantly higher when compared with matched plasma. Finally, the SOD-1 median value in no-cancer NAF was significantly higher (about 2-fold) than in cancer NAF. CONCLUSION: NAF measurement of SOD-1 is a useful tool to identify intracellular redox status of the breast microenvironment, mirroring the oxidative metabolic pathways occurring in breast tissue, both in physiologic and cancer conditions and in improving the identification of women at increased breast cancer risk. SOD-1 activity in the breast microenvironment may represent a functional "switch" between the detrimental/oncogenic properties and the oncosuppressor/proapoptotic role of this antioxidant enzyme.


Assuntos
Neoplasias da Mama/enzimologia , Fluido do Aspirado de Mamilo/enzimologia , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Adulto , Idoso , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Superóxido Dismutase/sangue , Superóxido Dismutase-1
8.
J Hazard Mater ; 172(2-3): 1677-80, 2009 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-19643541

RESUMO

The pyrometallurgic process that the exhausted batteries are submitted for the recovery of metallic lead generates great amount of a by-product called slag. The slag is composed mainly of iron ( approximately 60%) and lead ( approximately 6%), and this residue cannot be disposed in conventional landfill due to the high lead content. This work presents a new methodology for the extraction of lead from slag, based on the complexing effect of EDTA, a chelating ligand that has the ability to solubilize several heavy metals. As the iron (Fe(2+)/Fe(3+)) have a formation's constant with EDTA higher than the lead and is present in high concentrations in the samples, the fluoride ion (F(-)) was employed to mask the iron ions. The tests were carried out in a qualitative way, confirming the lead extraction by the formation of a yellow precipitate of lead iodide.


Assuntos
Conservação dos Recursos Naturais , Eletrônica , Chumbo/isolamento & purificação , Quelantes , Ácido Edético , Resíduos Industriais/prevenção & controle , Ferro/isolamento & purificação
9.
Expert Rev Endocrinol Metab ; 4(5): 493-505, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30736188

RESUMO

Breast cancer, a complex and multifactorial disease, is the most commonly diagnosed malignancy affecting women. Methods currently available for breast cancer detection have well-described limitations; in this respect, the intraductal approaches directly assess the microenvironment of the breast. Nipple aspirate fluid (NAF) can be noninvasively obtained from the breast in most women and represents a promising biological tool to assess metabolic, hormonal and molecular changes occurring in the cells lining the ducts, from which breast cancer arises. The aim of this review is to highlight the application of NAF studies in the field of biomarker discovery, which provide results useful for early detection and prevention of breast cancer risk; in fact, the analysis of NAF (mirroring the ductal-lobular microenvironment) is a reliable method for assessment of metabolic/hormonal pathways within the mammary gland, identifying biomolecular mechanisms of breast cancer initiation and progression. The intracrinology of breast microenvironment (i.e., hormonal status in NAF) may provide independent diagnostic/prognostic factors, highlighting the importance of early altered hormonal metabolism (e.g., aromatase, estrogen sulfotransferase and steroid sulfatase pathway) in relation to breast cancer initiation. The possible application of targeted therapies through the inhibition of intratumoral enzymes involved in steroid metabolism is also discussed. The intraductal approach to hormone analyses may provide a further panel of biomarkers providing clinical benefits and strengthening the armory against breast cancer.

10.
Water Res ; 38(17): 3699-704, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15350421

RESUMO

In this work the adsorption features of Na Y zeolite with the magnetic properties of iron oxides have been combined in a composite to produce a magnetic adsorbent. These magnetic composites can be used as an adsorbent for metallic contaminants in water and subsequently removed from the medium by a simple magnetic process. The zeolites:iron oxide magnetic composites, were prepared by using Na Y with weight ratio of 3:1 and were characterized by powder X-ray diffraction (XRD), magnetization measurements, chemical analyses, N(2) adsorption isotherms and Mössbauer spectroscopy. Nitrogen adsorption isotherms showed that the surface area decreased from 505 m(2)g(-1) for the pure Na Y to 353 m(2)g(-1) for the Na Y:Fe oxide 3:1 composite. The adsorption isotherms of metal ions Cr(3+), Cu(2+) and Zn(2+) from aqueous solution onto the composites also showed that the presence of iron oxide does not affect the adsorption capacity.


Assuntos
Cromo/isolamento & purificação , Cobre/isolamento & purificação , Poluentes da Água/isolamento & purificação , Purificação da Água/métodos , Zeolitas/química , Zinco/isolamento & purificação , Adsorção , Magnetismo
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