HPLC-DAD based method for the quantification of flavonoids in the hydroethanolic extract of Tonina fluviatilis Aubl. (Eriocaulaceae) and their radical scavenging activity

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

Taxonomic studies of laelapid mites (Acari: Mesostigmata: Laelapidae) and their use in combination with entomopathogenic nematodes (Rhabditida: Steinernematidae, Heterorhabditidae) to control Frankliniella occidentalis (Thysanoptera: Thripidae)

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Genetic parameter estimates for feed efficiency and dry matter intake and their association with growth and carcass traits in Nellore cattle

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

Green tea extract and its major constituent, epigallocatechin-3-gallate, induce epithelial beta-defensin secretion and prevent beta-defensin degradation by Porphyromonas gingivalis

Background and Objective: Antimicrobial peptides, such as beta-defensins, secreted by gingival epithelial cells, are thought to play a major role in preventing periodontal diseases. In the present study, we investigated the ability of green tea polyphenols to induce human beta-defensin (hBD) secretion in gingival epithelial cells and to protect hBDs from proteolytic degradation by Porphyromonas gingivalis.Material and Methods: Gingival epithelial cells were treated with various amounts (25-200 mu g/mL) of green tea extract or epigallocatechin-3-gallate (EGCG). The secretion of hBD1 and hBD2 was measured using ELISAs, and gene expression was quantified by real-time PCR. The treatments were also carried out in the presence of specific kinase inhibitors to identify the signaling pathways involved in hBD secretion. The ability of green tea extract and EGCG to prevent hBD degradation by proteases of P. gingivalis present in a bacterial culture supernatant was evaluated by ELISA.Results: The secretion of hBD1 and hBD2 was up-regulated, in a dose-dependent manner, following the stimulation of gingival epithelial cells with a green tea extract or EGCG. Expression of the hBD gene in gingival epithelial cells treated with green tea polyphenols was also increased. EGCG-induced secretion of hBD1 and hBD2 appeared to involve extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase. Lastly, green tea extract and EGCG prevented the degradation of recombinant hBD1 and hBD2 by a culture supernatant of P. gingivalis.Conclusion: Green tea extract and EGCG, through their ability to induce hBD secretion by epithelial cells and to protect hBDs from proteolytic degradation by P. gingivalis, have the potential to strengthen the epithelial antimicrobial barrier. Future clinical studies will indicate whether these polyphenols represent a valuable therapeutic agent for treating/preventing periodontal diseases.

Study of thermal decomposition of ignition temperature of bagasse, coal and their blends

In Brazil, due to its availability, sugar cane bagasse has a high potential for power generation. The knowledge of ignition behavior, as well as the knowledge of the chemical kinetics, in of fuels combustion process is important features in boilers projects and in the stability of the combustion process control. The aim of this study is to investigate the thermal behavior of sugar cane bagasse, coal and their blends. The methodology proposed by Tognotti et al. (1985) was applied to determine the ignition temperature for all samples. Ignition temperatures were 256oC for neat bagasse and 427oC for neat coal, and 275oC for both blends (50-50% and 25-75%). The ModelFree Kinetics was applied to determine the apparent activation energy (Eα) of the thermal decomposition of sugar cane bagasse. For the two major events of mass loss of bagasse which correspond to the thermal decomposition of organic matter (mainly hemicellulose, cellulose and lignin), average values of Eα were obtained for both combustion and pyrolysis processes. In synthetic air atmosphere, the Eα were 170.8±26.3 kJ⋅mol-1 and 277.8±58.6 kJ⋅mol-1, while in nitrogen atmosphere, the Eα were 185.0 ± 11.4 kJ⋅mol-1 and 82.1±44.4 kJ⋅mol-1. The results obtained can be explained by synergistic effects when both bagasse and coal were blended, changing the fuel reactivity.

Phytotoxicity of extracts and fractions of Ouratea spectabilis (Mart. ex Engl.) Engl. (Ochnaceae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Green tea extract and its major constituent epigallocatechin-3-gallate inhibit growth and halitosis-related properties of Solobacterium moorei

Background: Solobacterium moorei is a volatile sulfide compound (VSC)-producing Gram-positive anaerobic bacterium that has been associated with halitosis. The aim of this study was to investigate the effects of green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) on growth and severalhalitosis-related properties of S. moorei.Methods: A microplate dilution assay was used to determine the antibacterial activity of green tea extract and EGCG against S. moorei. Their effects on bacterial cell membrane integrity were investigated by transmission electron microscopy and a fluorescence-based permeability assay. Biofilm formation was quantified by crystal violet staining. Adhesion of FITC-labeled S. moorei to oral epithelial cells was monitored by fluorometry. The modulation of beta-galactosidase gene expression in S. moorei was evaluated by quantitative RT-PCR.Results: The green tea extract as well as EGCG inhibited the growth of S. moorei, with MIC values of 500 and 250 mu g/ml, respectively. Transmission electron microscopy analysis and a permeabilization assay brought evidence that the bacterial cell membrane was the target of green tea polyphenols. Regarding the effects of green tea polyphenols on the S. moorei colonization properties, it was found that biofilm formation on EGCG-treated surfaces was significantly affected, and that green tea extract and EGCG can cause the eradication of pre-formed S. moorei biofilms. Moreover, both the green tea extract and EGCG were found to reduce the adherence of S. moorei to oral epithelial cells. The beta-galactosidase activity of S. moorei, which plays a key role in VSC production, was dose-dependently inhibited by green tea polyphenols. In addition, EGCG at 1/2 MIC significantly decreased the beta-galactosidase gene expression.Conclusion: Our study brought evidence to support that green tea polyphenols possess a number of properties that may contribute to reduce S. moorei-related halitosis. Therefore, these natural compounds may be of interest to be used to supplement oral healthcare products.

Effects of acetylation and acetylation-hydroxypropylation (dual-modification) on the properties of starch from Carioca bean (Phaseolus vulgaris L.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thrombocytopenia and platelet hypoaggregation induced by Bothrops asper snake venom Toxins involved and their contribution to metalloproteinase-induced pulmonary hemorrhage

Thrombocytopenia and platelet dysfunction occur in patients bitten by Bothrops sp snakes in Latin America. An experimental model was developed in mice to study the effects of B. asper venom in platelet numbers and function. Intravenous administration of this venom induces rapid and prominent thrombocytopenia and ex vivo platelet hypoaggregation. The drop in platelet numbers was primarily due to aspercetin, a protein of the C-type lectin family which induces von Willebrand factor-mediated platelet aggregation/agglutination. In addition, the effect of class P-III hemorrhagic metalloproteinases on the microvessel wall also contributes to thrombocytopenia since jararhagin, a P-III metalloproteinase, reduced platelet counts. Hypoaggregation was associated with the action of procoagulant and defibrin(ogen)ating proteinases jararacussin-1 (a thrombin-like serine proteinase) and basparin A (a prothrombin activating metalloproteinase). At the doses which induced hypoaggregation, these enzymes caused defibrin(ogen)ation, increments in fibrin(ogen) degradation products and D-dimer and prolongation of the bleeding time. Incubation of B. asper venom with batimastat and α 2-macroglobulin abrogated the hypoaggregating activity, confirming the role of venom proteinases in this effect. Neither aspercetin nor the defibrin(ogen)ating and hypoaggregating components induced hemorrhage upon intravenous injection. However, aspercetin, but not the thrombin-like or the prothrombin-activating proteinases, potentiated the hemorrhagic activity of two hemorrhagic metalloproteinases in the lungs. © 2005 Schattauer GmbH, Stuttgart.

Antimicrobial activity of six plant extracts from the brazilian savanna on periodontal pathogens

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

Validation of an alternative analitycal method for the quantification of antioxidant activity in plant extracts

SUMMARY. A new method was developed to evaluate the total antioxidant activity in plant extracts, which was based on radical scavenging using 2,2’-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid. The proposed method was linear in the range of 0.86 to 26.0 μg/mL, displaying a correlation coefficient of 0.999. Moreover, the accuracy and precision analysis showed agreement with ANVISA guidelines (96.66 to 98.46 % and < 5.0%, respectively). The method demonstrated sensitivity, robustness and efficiency in detecting low concentrations of plant extracts (detection and quantification limit of 0.86 and 2.87 μg/mL, respectively) that may be present in pharmaceuticals and cosmetics preparations, again in agreement with ANVISA. In addition, the assay is inexpensive and easy to perform.

Synergism of crude extracts and essential oils from medicinal plants with antimicrobial drugs

The emergence of resistant strains to conventional antimicrobial drugs has been constant as well as research aimed new alternatives of antibacterial agents. Therefore, considering that natural products have been an important potential source of new antimicrobial drugs, aim to verify the synergism by disk and time kill curve method between antimicrobials (extracts-Ext. and essential oils-EO) from four plant and eight antimicrobial drugs against Staphylococcus aureus and Escherichia coli strains from human specimens. The S. aures strains were highly susceptible with all plant antimicrobials (eg., 1.24 mg/ml with Vernonia polyanthes Ext. and 2.21 mg/ml with Eugenia uniflora EO for the Minimal Inhibitory Concentration-MIC). According disk method, the Bacharis dracunculifolia and V. polyanthes EO had synergism with all eight tested drugs while only Matricaria chamomilla Ext. showed synergism against S. aureus. The synergism was found with V. polyanthes and E. uniflora Ext. while M. chamomilla Ext. had antagonism against E. coli strains. By time kill curve, the bacterial growth inhibition was superior when drugs were tested alone and the synergism effect also was verified. The antagonism effect was detected only for E. coli strains and only with Ext. Results indicated the potential use of these products as coadjutants during treatment of infectious diseases.

THE GLYCOPROTEINS OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS AND THEIR ROLE IN INFECTION AND IMMUNITY

The porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important pathogen of swine and is known to cause abortion and infertility in pregnant sows and respiratory distress in piglets. PRRSV contains a major glycoprotein (GP5) and three minor glycoproteins (GP2a, GP3, and GP4) on the virion envelope, all of which are required for infectious virus production. To study their interactions amongst each other and with a cellular receptor for PRRSV, CD163, I cloned each of the viral glycoproteins and CD163 in various expression vectors. My studies have shown that while the GP2a, GP3, and GP4 are co-translationally glycosylated, the GP5 is post-translationally glycosylated. By using co-immunoprecipitation (co-IP) assays, strong interaction was demonstrated between GP4 and GP5 proteins, although weak interactions among the other envelope glycoproteins were also detected. Further, GP4 was found to mediate interactions leading to formation of multiprotein glycoprotein complex. My results also show that GP2a and GP4 proteins are the only two GPs that specifically interact with the CD163 molecule and that glycosylation of these GPs is required for efficient interaction. Based on these studies, I have developed an interactome map of the viral GPs and CD163 and have proposed a model of the viral glycoprotein complex and its interaction with CD163. Studies reported here also show that glycan addition at residue 184 (N184) of GP2a, and residues N42, N50, and N131 of GP3 is essential for recovery of infectious virus. Although single site glycosylation mutants of GP4 had no effect on infectious virus production, introduction of double mutations was lethal. The loss of glycan moieties of GP2a, GP3, and GP4 proteins had no effect on host neutralizing antibody production. Overall, I conclude that the PRRSV glycoproteins are co-translationally and post-translationally glycosylated, the GP4 protein is central to mediating interglycoprotein interactions, and along with GP2a, serves as the viral attachment protein that is responsible for interactions with the viral receptor, CD163. Further, glycosylation of GP2a, GP3, and GP4 proteins is required for infectious virus production, efficient interaction with CD163, but does not play any role in neutralizing antibody response in infected animals.

SEASONAL, HABITAT AND SEX-SPECIFIC PATTERNS OF FOOD UTILIZATION BY RED-WINGED BLACKBIRDS (Agelaius phoeniceous) IN EASTERN ONTARIO AND THEIR ECONOMIC IMPORTANCE

Crop depredation by red-winged blackbirds (Agelaius phoeniceus) causes serious economic losses to agricultural crops each year in both Canada and the United States. The concentration of vulnerable, monocultural crops, particularly corn, during periods when large flocks of blackbirds congregate in roosting areas prior to migration has invariably led to heavy feeding pressure (Stone et al., 1972; Wiens and Dyer, 1975; Tyler et al., 1978). Efforts to reduce damage levels by mechanical and chemical dispersal agents have been largely unsuccessful, at least in terms of a long-term solution to the problem. Recently, the lethal control of blackbird populations using surfactants has been proposed. However, the potential repercussions of the removal of substantial numbers of birds from northern breeding areas are virtually unknown (Robertson et al., 1978). Much of the research dealing with the feeding ecology of red-winged blackbirds has been limited to fall and winter periods when large aggregations of birds are actively involved in crop depredation (Goddad, 1969; Williams, 1976; Dolbeer et al., 1978) or pose a potential health hazard (Monroe and Cronholm, 1976). However, what is not known is the degree to which the removal of deleterious weed seed and insect pests cited in several studies (Bird and Smith, 1964; Mott et al., 1972; Robertson et al., 1978) might be of potential value to agriculture. The issue of whether the benefits derived from redwing foraging compensate for the negative aspects associated with crop depredation and health hazards remains largely unresolved. The present study attempted to evaluate the pest status of this species using diet information derived from food habits analysis conducted during the residency of red- winged blackbirds in a northern breeding area. By determining how the feeding ecology of red-winged blackbirds varies on a seasonal basis, among different breeding habitats and between sexes, we hoped to determine more realistically which segments of the population might be responsible for the greatest benefits or detriments and, thereby, more accurately evaluate the economic impact of the species as a whole. To achieve this aim, the study provides an accurate description of the common insects and weed pests utilized by redwings. By determining the relative proportions of those items known to be detrimental, we hoped to illustrate, at least qualitatively, the degree to which redwing foraging is comprised of both beneficial and harmful components.

Soil profile, relief features and their relation to structure and distribution of Brazilian Atlantic rain forest trees

In tropical forests, the environmental heterogeneity can provide niche partitioning at local scales and determine the diversity and plant species distribution. Thus, this study aimed to investigate the variations of tree species structure and distribution in response to relief and soil profile features in a portion of the largest remnant of Brazilian Atlantic rain forest. All trees >= 5 cm diameter at breast height were recorded in two 0.99 ha plots. Topographic survey and a soil characterization were accomplished in both plots. Topsoil samples (0-20 cm) were taken from 88 quadrats and analyzed for chemical and particle size properties. Differences for both diversity and tree density were identified among three kinds of soils. A canonical correspondence analysis (CCA) indicated that the specific abundance varied among the three kinds of soils mapped: a shallow Udept - Orthent / Aquent gradient, probably due to differences in soil drainage. Nutrient content was less likely to affect tree species composition and distribution than relief, pH, Al3+, and soil texture. Some species were randomly distributed and did not show restriction to relief and soil properties. However, preferences in niche occupation detected in this study, derived from the catenary environments found, rise up as an important explanation for the high tree species diversity in tropical forests.