The formation of protochlorophyllide and protochlorophyllide phytyl ester was investigated during etioplast biogenesis in order to study the biosynthetic relation of these two compounds. Protochlorophyllide accumulates slowly during the first 2 days of germination, its rate of formation increases sharply during the 3rd day, and then it decreases. Protochlorophyllide phytyl ester starts accumula...

This investigation describes the synthesis and biological evaluation of a series of oxabicyclic analogues related to the helminthosporins. Four oxabicycles were prepared by [4+3] cycloaddition of an oxyallyl carbocation, generated in situ from 2,4-dibromopentan-3-one, with selected furans. Functional group manipulations of the oxabicyclic architecture generated nine further derivatives. The phy...

We present a simple subtraction procedure of GDDSC as a modification of the original DSC and GDRDA methods. Genetically Directed Differential Subtraction Chain (GDDSC) is a process by which highly related genomes are compared in order to isolate tags carrying the polymorphisms. To detect specific DNA fragment (tag), we can then monitor offspring plants for efficient molecular breeding. The GDDS...

1-Aminocyclopropane-1-carboxylic acid (ACC) level, ACC synthase activity, and ethylene production in cucumbers (Cucumis sativus L.) remain low while the fruit are held at a temperature which causes chilling injury (2.5 degrees C) and increase rapidly only upon transfer to warmer temperatures. The increase in ACC synthase activity during the warming period is inhibited by cycloheximide but not c...

O ácido 6α,7β-di-hidroxivouacapan-17β-óico (1) e o 6α,7β-di-hidroxivouacapan-17β-oato de metila (2) são produtos naturais isolados do extrato hexânico de frutos de Pterodon polygalaeflorus Benth. Este trabalho descreve a preparação e caracterização por espectroscopias no infravermelho, de ressonância magnética nuclear e por análise elementar do derivado inédito 6α,7βtiocarbonildioxivouacapan-17...

Five-day-old etiolated cucumber (Cucumis sativus L. var. Alpha Green) cotyledons produced more chlorophyll over a 4-hour illumination period after a prolonged exposure (12 to 72 hours) in the dark to ethylene concentrations ranging from 0.1 to 10 mul/l. Intact seedlings and excised cotyledons responded in the same way to this treatment. This effect does not involve a shortening of the lag phase...