Perforated ray cells in the wood of roots and branches of cerrado species from Brazil

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

The Tomato (Solanum Lycopersicum cv. Micro-Tom) Natural Genetic Variation Rg1 and the DELLA Mutant Procera Control the Competence Necessary to Form Adventitious Roots and Shoots

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

Anti-inflammatory effects and acute toxicity of hydroethanolic extract of Jacaranda decurrens roots in adult male rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anti-clastogenic effect of beta-glucan extracted from barley towards chemically induced DNA damage in rodent cells

beta-Glucan (BG) was tested in vitro to determine its potential clastogenic and/or anti-clastogenic activity, and attempts were made to elucidate its possible mechanism of action by using combinations with an inhibitor of DNA polymerase. The study was carried out on cells deficient (CHO-k1) and cells proficient (HTC) in phases I and II enzymes, and the DNA damage was assessed by the chromosomal aberration assay. BG did not show a clastogenic effect, but was anti-clastogenic in both cell lines used, and at all concentrations tested (2.5, 5 and 10 mg/mL) in combination with damage inducing agents (methylmethane sulfonate in cell line CHO-k1, and methylmethane sulfonate or 2-aminoanthracene in cell line HTC). BG also showed a protective effect in the presence of a DNA polymerase beta inhibitor (cytosine arabinoside-3-phosphate, Ara-C), demonstrating that BG does not act through an anti-mutagenic mechanism of action involving DNA polymerase beta.

Evaluation of antimutagenic activity and mechanisms of action of beta-glucan from barley, in CHO-k1 and HTC cell lines using the micronucleus test

Due to the need to identify new antimutagenic agents and to determine their mechanism of action, the present study examined the mechanism of action of the P-glucan with regard to antimutagenicity using the micronucleus assay in CHO-kl and HTC cell lines. The mutagenicity experiments were performed with three different concentrations of P-glucan (5, 10, and 20 mu g/mL), in wich only the highest dose showed mutagenic activity. In the antimutagenicity experiments, the same concentrations of P-glucan were combined with a mutagenic agent, methylmethane sulfonate, or 2-aminoanthracene, using four different treatment protocols: pre-treatment, simultaneous treatment (simple and with pre-incubation), and post-treatment. The results indicate that the CHO-kl cell line treated with MMS presented a chemopreventive activity for all the doses of P-glucan in the different treatment protocols, except for the lowest dose in post-treatment. When HTC cell line treated with MMS is analysed, a chemopreventive activity can be verified for the highest dose in both pre- and post-treatment. For the simple simultaneous treatment, the three doses demonstrated efficacy, while for the simultaneous treatment with pre-incubation only the intermediate concentration was effective. In HTC treated with 2AA both the lowest dose in the pre-treatment protocol and the post-treatment protocol did not show efficacy in preventing DNA damage. The evaluation of the different protocols and the damage decrease percentages observed suggest that P-glucan has both desmutagenic and bioantimutagenic activity. It is necessary, however, to note that efficacy and mechanism of action are subject to variation when compared the two cell lines, since in HTC, representing a drug-metabolizing system, this substance can show a diminished chemopreventive capacity. (c) 2006 Elsevier Ltd. All rights reserved.

Protective effects of beta-glucan extracted from barley against benzo[a]pyrene-induced DNA damage in hepatic cell HepG2

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Intracellular papillae of Actinocephalus (Eriocaulaceae-Poales) roots and their interaction with fungi: A light and transmission electron microscopy study

The genus Actinocephalus comprises 25 species and is restricted to Brazil, occurring mainly in the Espinhaco Mountains of Minas Gerais and Bahia States. Previous anatomical studies have reported the occurrence of intracellular papillae in the Actinocephalus roots, without dealing with their ultrastructure and function. The purpose of this paper is to investigate the structure, the composition and the probable function of the intracellular papillae of Actinocephalus roots, based on light microscopy, transmission electron microscopy and histochemical tests. The intracellular papillae occurred in all root tissues, from the rhizodermis to the vascular cylinder; they presented different forms and sizes and, ultrastructurally, they corresponded to material deposited between the cell wall and the plasma membrane. The histochemical tests carried out were positive for cellulose, pectin and callose. The intracellular papillae are responses of the plant cells to the interaction with fungi. They work as a physical barrier restricting fungal penetration, and they may also favor the supply of water and nutrients to the plant, since they increase root absorption surface. This might explain why the species of Actinocephalus are among the tallest Eriocaulaceae despite their reduced radicular system and the nutritional deficiency of the soil in which they grow. (C) 2006 Elsevier Ltd. All rights reserved.

Resistance to compression of weakened roots subjected to different root reconstruction protocols

Objective: This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. Material and methods: Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10), according to the root reconstruction protocol: Group I (control): non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45 degrees in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (alpha=0.05). Results: Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. Conclusion: The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol.

Postharvest conservation of the tuberous roots of Pachyrhizus Ahipa (Wedd) Parodi

O objetivo deste trabalho foi avaliar o período de armazenamento em diferentes temperaturas e embalagens na conservação das raízes de Pachyrhizus ahipa. As raízes foram colhidas, lavadas e armazenadas em bandejas de isopor, no refrigerador, câmara fria e à temperatura ambiente. As embalagens utilizadas foram PVC, saco plástico e sem embalagem (controle). As bandejas foram retiradas do seu ambiente de armazenamento e analisadas quanto a acidez total titulável, sólidos solúveis totais, pH, teores de cinzas, lipídios, carboidrato total e proteínas em base seca. A menor perda de massa das raízes foi em câmara fria e em saco plástico. A ATT manteve-se maior nas raízes armazenadas em câmara fria e na embalagem de PVC; os menores teores de SST foram observados em câmara fria não variando entre as embalagens. em todos os tratamentos a porcentagem média de carboidratos foi 84,9%. A porcentagem de lipídios foi maior nas raízes armazenadas em temperatura ambiente, entretanto, o teor de proteína e cinzas foram maiores nas armazenadas na geladeira. A melhor condição para o armazenamento das raízes é em câmara fria e embaladas com saco plástico, onde as raízes mantiveram a qualidade apropriada para comercialização durante até 30 dias de armazenamento.

Planting time, developmental stages and characteristics of roots and starch of Pachyrhizus ahipa

De forma geral, as características do amido variam não somente com a planta de origem, mas também com o estádio de desenvolvimento desta. Neste trabalho objetivou-se avaliar a influência da época de plantio e estádio de desenvolvimento da planta de ahipa sobre as características físico-químicas das raízes, tamanho de grânulos do amido e suas propriedades viscográficas. Constatou-se influência do estádio de desenvolvimento da planta nas características físico-químicas das raízes e do amido, independentemente da época de plantio. A melhor época para o plantio de Pachyrhizus ahipa é outubro e a colheita deve ser feita no máximo com 9 meses, adotando-se o procedimento de retirada das flores a partir dos 3 meses.

Action of auxins and/or boron, in the process of formation of roots in cuttings of coffee (Coffea-Arabica L CV Mundo-Novo)

The objective of present research was to verify the IBA and/or NAA effects with boron, on rooting of coffee (Coffea arabica L. cv 'Mundo Novo') stem cuttings. Therefore it were used stem cuttings from semi-hardwood orthotropous branches, having two nodes, with aproximately 10 cm of lenght. The cuttings were treateds during 24 hours with IBA and/or NAA plus boron solutions. The treatments' effect was observed trough the following observation, 90 days after planting: rooting percentage and number of cuttings with ''callus''. Trough the resultS obtained, it was concluded that, for obtaining more rooting of cuttings, the best treatment was NAA at 200 ppm plus boron or, the combination of IBA and NAA at 200 ppm plus boron.

Antifungal constituents from roots of Virola surinamensis

Chromatographic fractionation of the dichloromethane extract from roots of Virola surinamensis yielded two new natural products, 3-epi-juruenolide C and 2'-hydroxy-7,4'-dimethoxyisoflavone, as well as various known steroids, lignans, isoflavones, flavonoids and diarylpropanes. of these, alpha,2'-dihydroxy-4,3'-dimethoxydihydrochal biochanin A and 2'-hydroxy-7,4'-dimethoxyisoflavone displayed antifungal activity against Cladosporium cladosporioides at a minimum amount of 5 mu g, whereas 7-hydroxyflavanone and 7-hydroxy-4'-methoxyisoflavone exhibited an antifungal activity 10-fold higher than the positive control Nystatin. (C) 1999 Elsevier B.V. Ltd. All rights reserved.