This study aimed to investigate the reaction of unripe and ripe fruits of Capsicum spp. accessions to Colletotrichum gloeosporioides during the pre- and post-harvest periods, and to identify sources of resistance for use in plant breeding programs. Thirty-seven Capsicum spp. accessions of the Universidade Estadual do Norte Fluminense Darcy Ribeiro were evaluated. They were cultivated in a greenhouse and arranged in a completely randomized design with five replications. Twenty fruits from each accession were inoculated at two stages (unripe and ripe) in two different environments (fruits inoculated in the plant and detached fruit inoculated under laboratory conditions). The symptoms were assessed every 24 hours between the 1st and 8th days after inoculation. There were highly significant differences in the values of the area under the disease progress curve and in severity, considering all sources of individual variation and their interactions. Values of low and moderate correlation were observed for inoculation of unripe and ripe fruit in both environments. These results indicate the existence of distinct genes responsible for resistance at different stages of fruit development. Complete lack of symptoms was registered only for accessions UENF 1718 and UENF 1797 (C. baccatum var. pendulum).

Evidence based on immunological cross-reactivity and anti-diabetic properties has suggested the presence of insulin-like peptides in plants. The objective of the present study was to investigate the presence of insulin-like proteins in the leaves of Bauhinia variegata ("pata-de-vaca", "mororó"), a plant widely utilized in popular medicine as an anti-diabetic agent. We show that an insulin-like protein was present in the leaves of this plant. A chloroplast protein with a molecular mass similar to that of bovine insulin was extracted from 2-mm thick 15% SDS-PAGE gels and fractionated with a 2 x 24 cm Sephadex G-50 column. The activity of this insulin-like protein (0.48 mg/mL) on serum glucose levels of four-week-old Swiss albino (CF1) diabetic mice was similar to that of commercial swine insulin used as control. Further characterization of this molecule by reverse-phase hydrophobic HPLC chromatographic analysis as well as its antidiabetic activity on alloxan-induced mice showed that it has insulin-like properties. Immunolocalization of the insulin-like protein in the leaves of B. variegata was performed by transmission electron microscopy using a polyclonal anti-insulin human antibody. Localization in the leaf blades revealed that the insulin-like protein is present mainly in chloroplasts where it is also found associated with crystals which may be calcium oxalate. The presence of an insulin-like protein in chloroplasts may indicate its involvement in carbohydrate metabolism. This finding has strengthened our previous results and suggests that insulin-signaling pathways have been conserved through evolution.

Experimentos relativos à purificação do vírus da necrose branca do fumo, em geral instável aos processos de purificação, mostraram ser possível obter preparações razoàvelmente homogêneas partindo-se de plantas por êle infetadas. O processo de purificação constou de uma clarificação preliminar através da adsorção de diversos componentes do suco de planta, ao qual foi adicionado dietilditiocarbamato de sódio a 0,1 M e tampão de fosfato pH 8,0 e a 0,1 M em fosfato hidradatado de cálcio, seguida de ultracentrifugações diferenciais. Os resultados das purificações a partir de Nicotiana tabacum L. var. xanthi, Solanum nigrum L. e Datura stramonium L. doentes, mostraram-se consistentes com respeito à presença de pellets após duas ultracentrifugações, o mesmo não acontecendo com as plantas contrôles. Tais preparações apresentaram infetuosidade até o terceiro dia após a extração do suco. Exames ao microscópio eletrônico das suspensões das pellets acima mencionadas em água destilada, mostraram a existência de partículas esferóides com um diâmetro ao redor de 50 milimicra. Injeções em coelho, via íntravenosa, num total de 7 doses de 2-3 ml de suspensão do vírus da necrose branca do fumo, preparadas diariamente pelo processo já referido, mas com uma só ultracentrifugação, provocaram a formação de anticorpos para o mesmo, conforme se pôde constatar pelos testes de precipitina de difusão em ágar.

This work presents the results of the purification of the Brazilian tobacco streak virus from material of different three host plant species. The procedure consisted of a preliminar clarification through the adsorption of several components of the juice from diseased plants extracted with phosphate buffer at pH 8,0, 0,1, M and sodium diethyl ditbio carbamate at 0,1 M on hidrated calcium phosphate and two or more ultracentrifugation cycles. Pellets were obtained from diseased Nicotiana tubacum L. var. xanthi Solanum nigrum L. and Datura stramonium and never from the healthy control plants after two ultracentrifugations. Suspension of such pellets in phosphate buffer and sodium diethyl ditio carbamate were infectious up to the third day after the juice extraction. The purified preparations when examined under electron microscope showed particles approximately spherical with a diameter around 50 mn. The preparations obtained after the clarification and one ultracentrifugation cycle when infected daily, intravenously, in one rabbit during 7 days promoted antibody formation to the Brazilian streak virus. The presence of antibody in the antiserum could be demonstrated in gel diffusion tests, but not in precipitin tests.

O vírus do mosaico do quenopódio foi purificado por meio de centrifugações alternadas de baixa e alta velocidade, complementadas pelo tratamento com clorofórmio e álcool amílico. Foram obtidas preparações altamente ativas, que apresentaram as reações características das proteínas e um espectro de absorção da luz ultravioleta igual ao das nucleoproteínas, e que não apresentavam o fenômeno de anisotropia de fluxo. O sedimento dessas preparações purificadas, obtido na ultracentrífuga, retomado em um pequeno volume de solução de sulfato de amônio 0,2 saturada e guardado a 4°C, produz um grande número de microcristais. As partículas que compõem as preparações examinadas ao microscópio são de aspecto e dimensões bastante uniformes; são "esféricas" e de cerca de 30 milimicros de diâmetro. O material purificado se assemelha ao vírus do mosaico "southern bean", quanto ao aspecto dos cristais, mas os testes de hospedeiros e sorológicos indicaram tratar-se de dois vírus perfeitamente distintos.

The Chenopodium mosaic virus was purified by means of alternated low and high speed centrifugations combined with chloroform N-amyl alcohol treatment. Such preparations have a high activity, give positive tests for protein and its ultra-violet absorption spectrum is that of a nucleoprotein solution. They do not show the phenomenon of anisotropy of flow. When examined in the electron microscope they showed to be constituted of "spherical" particles of uniform size having an approximate diameter of 30 mμ.. If a pellet of the purified virus is resuspended in a small volume of 0,2 saturated (NH4)2 SO4 solution and kept at 4°C for several hours, masses of roughly rhombic crystals are formed. As far as the size of particles and the form of crystals are concerned, the Chenopodium mosaic virus resembles the southern bean mosaic virus. They differ, however, in their host range and are not related serologically.