Inhibition of Nitric Oxide and Tumour Necrosis Factor-alpha Production in Peritoneal Macrophages by Aspergillus nidulans Melanin

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Theoretical insight into the mechanism for the inhibition of the cysteine protease cathepsin B by 1,2,4-thiadiazole derivatives

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Inhibition of Lysozyme by Taurine Dibromamine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Investigação das atividades alelopática, fitotóxica e antioxidante de extratos e frações de Tridax procumbens L. (Asteraceae). e Ouratea spectabilis (mart. ex engl.) engl. (Ochnaceae)

Pós-graduação em Biociências - FCLAS

Angiotensin II AT(1) receptor mutants expressed in CHO cells caused morphological change and inhibition of cell growth

To assess the importance of the leucine residues in positions 262 and 265 of the angiotensin AT, receptor for signaling pathways and receptor expression and regulation, we compared the properties of CHO cells transfected with the wild type or the L262D or L265D receptor point mutants. It was found that the two mutants significantly increased the basal intracellular cyclic AMP (cAMP) formation in an agonist-independent mode. The morphology transformation of CHO cells was correlated with the increased cAMP formation, since forskolin, a direct activator of adenylate cyclase mimicked this effect on WT-expressing CHO cells. DNA synthesis was found to be inhibited in these cell lines, indicating that cAMP may also have determined the inhibitory effect on cell growth, in addition to the cell transformation from a tumorigenic to a non-tumorigenic phenotype. However a role for an increased Ca2(+) influx induced by the mutants in non-stimulated cells cannot be ruled out since this ion also was shown to cause transformed cells to regain the morphology and growth regulation. (c) 2005 Elsevier B.V. All rights reserved.

Fluoride release and secondary caries inhibition by adhesive systems on root dentine

This study tested the fluoride-release rate and the root caries inhibitory effect of dental adhesives. In phase 1, the fluoride released from samples (n = 5) of the adhesives A (Optibond Solo), B (One-up Bond F), C (Prime & Bond NT), D (Tenure Quick), and also of the controls [+] (glass-ionomer cement) and [-] (non-fluoride releasing adhesive), was quantified on a daily basis during a pH-cycling, caries-simulating phenomenon. In phase 2, restorations were made in bovine root dentine slabs (n = 16) with the same adhesives associated with a non-fluoridated composite. Control [+] restorations were made entirely with glass-ionomer cement. Specimens were thermocycled and submitted to the pH-cycling regimen. Demineralization areas and the presence of the wall lesion (WL) and the inhibition zone (IZ) were determined by polarizing light microscopy in dentine adjacent to the restoration. The highest concentration of fluoride was released by the control [+]; adhesives A, B and C, also released fluoride. No detectable amount of fluoride was released by D or [-]. Smaller areas of demineralization were found with control [+], whereas the demineralization areas of adhesives A-D and [-] did not differ from each other. No WL was detected, and higher percentages of IZ were recorded to [+] and to adhesive A. Although some dental adhesives were able to release fluoride, they could not inhibit secondary caries development as well as the glass-ionomer cement.

Caries progression and inhibition in human and bovine root dentine in situ

Since the use of bovine instead of human dentine to evaluate cariogenic and anticariogenic substances is not well established, this in situ study was conducted. Eleven volunteers wore palatal acrylic devices containing 4 dentine slabs (2 human and 2 bovine). Sucrose solution (20%) was dripped over all slabs 4 times a day, simulating a cariogenic challenge. Dentifrice slurries, fluoridated or not, were dripped over specified dentine slabs 3 times a day to evaluate caries reduction. After 14 days, the biofilm formed on the dentine slabs was collected for microbiological analysis. In dentine, mineral loss (DeltaZ) and lesion depth (LD) were determined by cross-sectional microhardness and by polarized light microscopy, respectively. The total streptococci and mutans streptococci counts in the biofilm formed either on human or on bovine slabs, whether treated or not with fluoride dentifrice, were not statistically different. The DeltaZ and the LID values of dentine treated with fluoride dentifrice were significantly lower than the values of dentine treated with non-fluoride dentifrice. The differences in the DeltaZ and LD values between the human and bovine dentine were not statistically significant. The results suggest that bovine dentine can be used instead of human to evaluate caries development and inhibition. Copyright (C) 2003 S. Karger AG, Basel.

Allelopathic potential and survey of natural seed bank under the canopy of Copaifera Langsdorffii Desf

The aim of this study was to evaluate the allelopathic effect of soil samples collected under the canopies of three specimens of Copaifera langsdorffii the germination of Lactuca sativa and survey the natural seed bank according to seasonality. To test the allelopathic effect was carried experiments of pre and post-emergence with seeds of L. sativa and to quantify the stock of seeds, soil samples were collected from three specimens at three distances from the stem (1, 2 and 3 m) and at three depths (0-5, 5-10 and 10-15cm) in the region of savanna in the dry and wet seasons. The samples tested in bioassay of pre-emergence no significant influence on germinability, mean germination time and mean germination speed, but showed a difference in the synchronism of germination, these data were independent of sampling station. In test for post-emergence was observed statistical difference in the parameters evaluate (length of primary roots and hypocotyls) in both seasons. To quantify the natural seed bank were macroscopic analysis of each soil sample with the help of stereoscopic microscope. The analysis of the natural seed bank showed a larger number of seeds in the 0-5cm and in distance of 2m for both seasons. The results suggest the presence of allelochemical substances in soil samples collected under the canopy of Copaifera langsdorffii.

Evaluation of allelopathic potential of leaf extract of kielmeyera coriacea on lactuca sativa l

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of leaf extracts of Myrcia guianensis (Aubl.) DC. on growth and gene expression during root development of Sorghum bicolor (L.) Moench

The allelopathic potential of leaf extracts from the medicinal plant Myrcia guianensis (Aubl.) DC. was studied in Petri dish bioassays on sorghum and determined the seed germination, germination rate index (GRI), root growth, secondary root number, the genes involved in root development (SHR, PHB, PHV and REV) and microRNA 166 that regulates these genes. The hydroalcoholic extract was more inhibitory than methanol extract (moderate inhibition) and aqueous extract at 25 and 100% concentration were least inhibitory. Application of higher dose of hydroalcoholic M. guianenesis leaf extracts on sorghum seeds, inhibited the root development and changed the expression of SHR and PHB genes and microRNA 166. This suggested that the expression of these genes could be indicator of allelopathic potential for inhibition of root development in sorghum.

Phytotoxicity of Solanum aculeatissimum Jacq: leaves extract

The objective of this study was to evaluate the phytotoxicity of Solanum aculeatissimum Jacq. leaves ethanolic extract in seeds germination, development and fixation of Lactuca sativa seedlings. The same study also aimed to assess the mitotic index of lettuce roots meristematic cells, quantification of phenols and total flavonoids and triage by mean of phytochemical testing of the main secondary metabolites classes. Bioassays of germination, development of root and hypocotyl were carried out in Petri dishes using achenes of Lactuca sativa L. cv. 'Grand Rapids' (lettuce). Concomitantly, were evaluated the physico-chemical characteristics (pH, osmotic potential and electrical conductivity), mitotic index, quantification of total phenols and flavonoids and determination of phytochemical profile of the treatments extract. The results obtained in the bioassays demonstrate that the ethanol extract of S. aculeatissimuma presents phytotoxic potential in the development of lettuce seedlings, given that the concentration of 20 mg/ml showed greater inhibition (41% of germination). The extract contains significant amounts of antioxidants, total flavonoid and phenols, where the concentration 1000µg/mL showed higher values (86.50%). Furthermore, it was possible to observe the presence of compounds with allelopathic activity in the phytochemical screening test as coumarins, tannins, terpenes, flavonoids and alkaloids. Given the above it is clear that the ethanolic extract of S. aculeatissimum presents allelopathic substances with phytotoxic activity that can affect the germination and development of other plant species in their natural environment.

Inhibition of bladder cancer cell proliferation by allyl isothiocyanate (mustard essential oil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)