Sementes recalcitrantes: intolerantes a baixas temperaturas? Embriões recalcitrantes de Inga vera Willd. subsp. affinis (DC.) T. D. Penn. toleram temperatura sub-zero

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

Entomofauna visitante de Belamcanda chinensis (L.) DC (Iridaceae) durante o período de floração

A study of the reproductive biology of B. chinensis (L.) DC. (Iridaceae) was realized comprising floral biology and breeding systems. The floral biology studies included analyses of nectar production, occurence of osmophores, corolla pigments, ultraviolet reflexion and absortion patterns, viability of pollen, pollinators and flower visitors. The breeding systems were studied taking into account the results of manual pollinators tests. B. chinensis is self-compatible bul cross-pollination is more frequent. The effective pollinators are Plebeia droryana (Friese, 1906) (45,7%), Trigona spinipes (Fabricius, 1793) (27,3%), Tetragonisca angustula (Latreille, 1811) (9,3%). Others insects visitors are considered nectar and pollen thieves. The flowering begins generally in January and February. The complete reproductive cicle, as here considered, begining with floral bud production ending with development of mature fruits, lasts January to June. Seed dispersion is ornitocoric.

Composição química e produtividade dos principais componentes do óleo essencial de Baccharis dracunculifolia DC. em função da adubação orgânica

Objetivou-se avaliar a composição química e produtividade dos principais componentes do óleo essencial de Baccharis dracunculifolia DC. em função de doses de composto orgânico (0, 10, 20, 30, 40 e 50 t ha-1). Foi realizada uma colheita, aos 150 dias após o transplante das mudas. O óleo essencial, da massa seca útil da parte aérea, foi extraído por hidrodestilação e analisado em cromatógrafo a gás acoplado a espectrômetro de massas (Shimadzu, QP-5000). A identificação dos constituintes químicos foi realizada através da análise comparativa dos espectros de massas das substâncias com o banco de dados do sistema CG-EM (Nist 62.lib), literatura e índice de retenção. Os resultados foram submetidos à análise de variância pelo teste F, às médias obtidas foram submetidas à análise de regressão e o teste Tukey para o efeito das doses de composto orgânico. Os três componentes sesquiterpênicos, E-nerolidol, espatulenol e óxido de cariofileno, perfazem 58,44% da média relativa da composição química do óleo essencial de B. dracunculifolia, composto pela presença de 28 substâncias. Na produtividade dos componentes γ-muroleno, valenceno, δ-cadineno e E-nerolidol as dosagens estudadas influenciaram as plantas, que na dosagem 30 t ha-1 obtiveram os melhores resultados. Se o objetivo no cultivo de B. dracunculifolia for o componente espatulenol as dosagens 30 e 40 t ha-1 obtiveram os melhores resultados. Para a produtividade do componente óxido de cariofileno as dosagens estudadas influenciaram as plantas, que na dosagem 40 t ha-1 obtiveram os melhores resultados.

Change in the ascorbic-acid content of acerolas (Malpighia-glabra L) as function of harvest maturation degree and storage-temperature

The content of ascorbic acid was assayed in acerolas harvested in three phases of maturation: green-yellow fruits (I); light red (II) and wine-coloured (III). Phase I and Phase II fruit were packed in aluminium sheets and stoppered flasks and stored in freezer (-10o.C) and in refrigerator (8o.C). Samples of 8 fruits from each experimental condiction were analysed for ascorbic acid determination by 2-chlorophenol indophenol discolouration method. The averages of 1.393,5 mg./100g. for Phase I sample, 1024,9 for Phase II and 756,5 for Phase III fruits, showed a statistically significative linear decreasing of the ascorbic acid content related with the maturation extent Phase I samples stored in freezing showed statitically significative decreasing of that vitamin at 408 hours of storage in both: aluminium sheet and stoppered flask package; in chilling temperature there was significative reduction of ascorbic acid content after 240 and 312 hours, respectively, for fruits packed in aluminium sheet and stopped flasks. Phase Il samples showed significative lost at 72 hours of storage when maintained in freezing temperature either, in aluminium sheet or in stoppered flasks: When stored in chilling temperature showed progressive lost of ascorbic acid in all measuring periods in every package. After 144 hours suffered deterioration suggested by colour changes.

Constructive heuristic algorithm for the DC model in network transmission expansion planning

A novel constructive heuristic algorithm to the network expansion planning problem is presented the basic idea comes from Garver's work applied to the transportation model, nevertheless the proposed algorithm is for the DC model. Tests results with most known systems in the literature are carried out to show the efficiency of the method.

Production of low methoxyl pectin using immobilized pectin methylesterase silica from acerola (Malpighia glabra L.)

The aim of this work was to develop an efficient reactor for the production of low methoxyl pectin, using pectinmethylesterase (PME, EC 3.1.1.11) from acerola immobilized on silica. The immobilized enzyme was used in up to 50 successive bioconversion runs at 50 degrees C with an efficiency loss of less than 20%. The fixed-bed reactor (6.0 x 1.5 cm) was prepared using PME immobilized in glutaraldehyde-activated silica operated at 50 degrees C with an optimum flow rate of 10 mL h(-1). The bioconversion yield was shown to strongly depend on the nature of the enzymatic preparation. An efficiency of 44% was achieved when concentrated PME was used, compared with only 30% with purified PME, both after an 8-h run. The process described could provide the basis for the development of a commercial-scale process. (c) 2006 Society of Chemical Industry.

Immobilization of pectinmethylesterase from acerola (Malpighia glabra L.) in porous silica

The total and partially purified enzyme pectinmethylesterase from acerola fruit was covalently immobilized on porous silica particles. These efficiency values were 114% for the total PME and 351% for the partially purified PME. In both forms the immobilization resulted in compounds with high thermal stability.

Study of seed-germination and etiolation of seedlings in Emilia-sonchifolia (l) dc and Emilia-fosgerbii nicolson (Asteraceae)

The germination of seeds of Emilia sonchifolia (2n) and E. fosgerbii (4n) was analysed and our results indicate that the former present light insensitive seeds and the latter germinated only under continuous white light. The germination of seeds under shade light presented no differences between both species, However under continuous white light, which maintain 70% of Pfr, the velocity of germination was greater in Emilia sonchifolia when compared to Emilia fosbergii, indicating that the threshold of 4n seeds were greater than 2n seeds. The analysis of the fluence response curves for etiolating process indicated that the process presented no differences between both species. The same was observed for the effect of the shade light in the etiolating process.

Screening of supports for the immobilization of pectinmethylesterase from acerola (Malpighia glabra L)

A partially purified extract of pectinmethylesterase (PME) from acerola fruit was immobilized on various supports: glass, celite, chrysotile, agarose, concanavalin A Sepharose 4B, egg shell, polyacrylamide and gelatin. In addition, reticulation with glutaraldehyde was assessed, as well as the use of gelatin in the presence of celite, glass and silica. The highest immobilization yields were obtained when the pectinmethylesterase was immobilized in concanavalin A Sepharose 4B (81.7%) and in gelatin-water (78.0%). (C) 2004 Society of Chemical Industry.

THE B-FORM TO Z-FORM TRANSITION OF POLY(DG-M(5)DC) IS SENSITIVE TO NEUTRAL SOLUTES THROUGH AN OSMOTIC-STRESS

Several neutral solutes, ranging in size from methanol to a tetrasaccharide, stachyose, are shown to stabilize the left-handed Z form of the methylated polynucleotide poly(dG-m(5)dC). The action of these solutes is consistent with an osmotic stress, that is, with their effect on water chemical potentials coupled to a difference in the number of-associated water molecules between the B and Z conformations. The apparent difference in hydration between the two forms is, however, dependent on the particular solute used to probe the reaction. The effect of solutes is not consistent either with a direct binding of solute or with an indirect effect on electrostatics or ion binding through changes in the solution dielectric constant. The interplay of NaCl and neutral solute in modulating the B-Z transition suggests that salt also could be stabilizing the Z form through an osmotic stress.

Partial purification and characterization of pectin methylesterase from acerola (Malpighia glabra L.)

The enzyme pectin methylesterase (PME) is present in acerola fruit and was partially purified by gel filtration on Sephadex G-100. The results of gel filtration showed different PME isoforms. The total PME (precipitated by 70% salt saturation) and one of these isoforms (fraction from Sephadex G-100 elution) that showed a molecular mass of 15.5 +/- 1.0 kDa were studied. The optimum pH values of both forms were 9.0. The total and the partially purified PME showed that PME specific activity increases with temperature, the total acerola PME retained 13.5% of its specific activity after 90 min of incubation at 98 degreesC. The partially purified acerola (PME isoform) showed 125.5% of its specific activity after 90 min of incubation at 98 degreesC. The K-m values of the total PME and the partially purified PME isoform were 0.081 and 0.12 mg/mL, respectively. The V-max values of the total PME and the partially purified PME were 2.92 and 6.21 mumol/min/mL/mg of protein, respectively.

A 12 kW three-phase low THD rectifier with high-frequency isolation and regulated DC output

A robust 12 kW rectifier with low THD in the line currents, based on an 18-pulse transformer arrangement with reduced kVA capacities followed by a high-frequency isolation stage is presented in this work. Three full-bridge (buck-based) converters are used to allow galvanic isolation and to balance the dc-link currents, without current sensing or current controller. The topology provides a regulated dc output with a very simple and well-known control strategy and natural three-phase power factor correction. The phase-shift PWM technique, with zero-voltage switching is used for the high-frequency dc-dc stage. Analytical results from Fourier analysis of winding currents and the vector diagram of winding voltages are presented. Experimental results from a 12 kW prototype are shown in the paper to verify the efficiency, robustness and simplicity of the command circuitry to the proposed concept.

Abortive and teratogenic effect of Acanthospermum hispidum DC. and Cajanus cajan (L.) Millps. in pregnant rats

Extracts of Acanthospermum hispidum and Cajanus cajan have been used by Brazilian people in an attempt to produce abortion. In order to evaluate the possible abortive and/or teratogenic effect of these plant extracts, female Wistar rats were treated with the aqueous extract (infusion, proportion C. cajan and A. hispidum 1:1.3). Doses of 0, 150, 300 and 600 mg/kg were daily administered by gavage during the organogenic period. The animals were sacrificed at term. There was no significant change in the mean weight of the fetuses, and no change in the percentage of post implantation loss in the treated groups. However, there was an increase in the number of external malformations, and this was related to dose. No internal malformations were observed in fetuses at term, but there was a significant incidence of fetuses with visceral anomalies. The tendency of the pregnancy to continue or terminate did not change with the treatment.