Figueiredo J.M.,Federal University of Rio de Janeiro |
Figueiredo J.M.,Instituto Nacional da Propriedade Industrial INPI |
Rodrigues D.C.,Federal University of Rio de Janeiro |
Silva R.C.M.C.,Federal University of Rio de Janeiro |
And 7 more authors.
Molecular and Biochemical Parasitology | Year: 2012
In this study, we characterized ceramide synthase (CerS) of the protozoan parasite Trypanosoma cruzi at the molecular and functional levels. TcCerS activity was detected initially in a cell-free system using the microsomal fraction of epimastigote forms of T. cruzi, [ 3H]dihydrosphingosine or [ 3H]sphingosine, and fatty acids or acyl-CoA derivatives as acceptor or donor substrates, respectively. TcCerS utilizes both sphingoid long-chain bases, and its activity is exclusively dependent on acyl-CoAs, with palmitoyl-CoA being preferred. In addition, Fumonisin B 1, a broad and well-known acyl-CoA-dependent CerS inhibitor, blocked the parasite's CerS activity. However, unlike observations in fungi, the CerS inhibitors Australifungin and Fumonisin B 1 did not affect the proliferation of epimastigotes in culture, even after exposure to high concentrations or after extended periods of treatment. A search of the parasite genome with the conserved Lag1 motif from Lag1p, the yeast acyl-CoA-dependent CerS, identified a T. cruzi candidate gene (TcCERS1) that putatively encodes the parasite's CerS activity. The TcCERS1 gene was able to functionally complement the lethality of a lag1Δ lac1Δ double deletion yeast mutant in which the acyl-CoA-dependent CerS is not detectable. The complemented strain was capable of synthesizing normal inositol-containing sphingolipids and is 10 times more sensitive to Fumonisin B 1 than the parental strain. © 2011 Elsevier B.V. All rights reserved.
Nascimento L.B.S.,Federal University of Rio de Janeiro |
Leal-Costa M.V.,Federal University of Rio de Janeiro |
Coutinho M.A.S.,Federal University of Rio de Janeiro |
Moreira N.D.S.,Federal University of Rio de Janeiro |
And 5 more authors.
Photochemistry and Photobiology | Year: 2013
Antioxidant compounds protect plants against oxidative stress caused by environmental conditions. Different light qualities, such as UV-A radiation and blue light, have shown positive effects on the production of phenols in plants. Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) is used for treating wounds and inflammations. Some of these beneficial effects are attributed to the antioxidant activity of plant components. We investigated the effects of blue light and UV-A radiation supplementation on the total phenol content, antioxidant activity and chromatographic profile of aqueous extracts from leaves of K. pinnata. Monoclonal plants were grown under white light, white plus blue light and white plus UV-A radiation. Supplemental blue light improved the antioxidant activity and changed the phenolic profile of the extracts. Analysis by HPLC of supplemental blue-light plant extracts revealed a higher proportion of the major flavonoid quercetin 3-O-α-l-arabinopyranosyl (1→2) α-l-rhamnopyranoside, as well as the presence of a wide variety of other phenolic substances. These findings may explain the higher antioxidant activity observed for this extract. Blue light is proposed as a supplemental light source in the cultivation of K. pinnata, to improve its antioxidant activity. This study reports a potential use of blue light as a supplemental light source in cultivation of Kalanchoe pinnata, an important medicinal species. We investigated the effects of blue and UV-A light supplementation on the total phenol content, antioxidant activity and chromatographic profile of K. pinnata extracts. Supplemental blue light improved the antioxidant activity and changed the phenolic profile. Analysis by HPLC of supplemental blue-light plant extracts (A) revealed a higher proportion of the major flavonoid in K. pinnata, as well as the presence of quercitrin and a wide variety of other phenolic substances, when compared with control (B). © 2012 The American Society of Photobiology.
Cavalheiro G.M.D.C.,Getulio Vargas Foundation |
Cavalheiro G.M.D.C.,Instituto Nacional da Propriedade Industrial INPI |
Joia L.A.,Getulio Vargas Foundation |
World Patent Information | Year: 2014
For most of its history, Brazil needed to import oil to complement its internal production to supply the internal demand. However, in 2007, the Brazilian Federal Government announced the discovery of huge hydrocarbon resources in the pre-salt layer of the country's Southeastern coast. This study examines the impact of this discovery accomplished by Petróleo Brasileiro S.A. (Petrobras) on patent applications in Brazil associated with upstream oil and gas technologies. Then, this article provides empirical evidence that the pre-salt discovery significantly affected patent strategizing of Multi-Nationals Companies (MNCs) operating in the upstream oil and gas industry, thereby generating a boom in patent filings in Brazil from the official pre-salt announcement onwards. © 2014 Elsevier Ltd.
De Souza E.R.,Pontifical Catholic University of Rio de Janeiro |
De Souza E.R.,Instituto Nacional da Propriedade Industrial INPI |
Mont'Alvao C.,Pontifical Catholic University of Rio de Janeiro
Work | Year: 2012
It is essential that access to information must to be universal given the importance of having a truly global Internet. This study proposes to evaluate a government website with two semiautomatic accessibility evaluation tools. The results have demonstrated that the use of more than one semi-automatic assessment tool can provide enhanced results. The differences in results and presentation in the reports generated by the two tools indicate that there is more complete results by combining tests with different accessibility evaluation tools. © 2012 - IOS Press and the authors. All rights reserved.
Da Silva D.,Federal University of Rio de Janeiro |
Casanova L.M.,Federal University of Rio de Janeiro |
Marcondes M.C.,Federal University of Rio de Janeiro |
Espindola-Netto J.M.,Federal University of Rio de Janeiro |
And 6 more authors.
IUBMB Life | Year: 2014
The aim of this study was to evaluate the antidiabetic potential of a leaf extract and flavonoids from Sedum dendroideum (SD). Additionally, our goals were to establish a possible structure/activity relationship between these flavonoids and to assess the most active flavonoid on the glycolytic enzyme 6-phosphofructo-1-kinase (PFK). SD juice (LJ), a flavonoid-rich fraction (BF), and separately five flavonoids were evaluated intraperitoneally for their acute hypoglycemic activity in normal and streptozotocin-induced diabetic mice. First, the major flavonoids kaempferol 3,7-dirhamnoside or kaempferitrin (1), kaempferol 3-glucoside-7-rhamnoside (2), and kaempferol 3-neohesperidoside-7- rhamnoside (3) were tested. Then, the monoglycosides kaempferol 7-rhamnoside (5) and kaempferol 3-rhamnoside (6) were assayed to establish their structure/activity relationship. The effect of 1 on PFK was evaluated in skeletal muscle, liver, and adipose tissue from treated mice. LJ (400 mg/kg), BF (40 mg/kg), and flavonoid 1 (4 mg/kg) reduced glycemia in diabetic mice (120 min) by 52, 53, and 61%, respectively. Flavonoids 2, 3, 5, and 6 were inactive or showed little activity, suggesting that the two rhamnosyl moieties in kaempferitrin are important requirements. Kaempferitrin enhanced the PFK activity chiefly in hepatic tissue, suggesting that it is able to stimulate tissue glucose utilization. This result is confirmed testing kaempferitrin on C2C12 cell line, where it enhanced glucose consumption, lactate production, and the key regulatory glycolytic enzymes. The hypoglycemic activity of kaempferitrin depends on the presence of both rhamnosyl residues in the flavonoid structure when intraperitoneally administered. Our findings show for the first time that a flavonoid is capable of stimulating PFK in a model of diabetes and that kaempferitrin stimulates glucose-metabolizing enzymes. This study contributes to the knowledge of the mechanisms by which this flavonoid exerts its hypoglycemic activity. © 2014 International Union of Biochemistry and Molecular Biology.