Differential expression after UV-B radiation and characterization of chalcone synthase from the Patagonian hairgrass Deschampsia antarctica.

Deschampsiaantarctica inhabits the maritime territory of Antarctica and South Patagonia. It grows under very harsh environmental conditions. The survival of this species in low freezing temperatures and under high levels of UV-B radiation may constitute some of the most remarkable adaptive plant responses and suggests that this plant possesses genes associated with cold and UV tolerance.

Sesquiterpenes, flavonoids, shikimic acid derivatives and pyrrolizidine alkaloids from Senecio kingii Hook.

Twenty-four compounds including eleven eremophilanolides (1-11), one eremophilane (13), five shikimic acid derivatives (14-18), six flavonoids (19-24), and the macrocyclic unsaturated pyrrolizidine alkaloid integerrimine (25) were isolated from Senecio kingii, an endemic species from the Magallanes Region (Chile). Compounds 3, 5, 6, 8-11 and 13-18 have not been previously reported as natural products. Their molecular structures were determined by NMR spectroscopic analysis and comparison with published NMR data.

The recurvatianes: a suite of oxygenated guaiane sesquiterpenes from Perezia recurvata.

Six guaiane sesquiterpenes recurvatiane A-F, including the previously known recurvatiane E and xanthomicrol, were isolated from the Andean Perezia recurvata and their structures determined by spectroscopic evidence. The absolute stereochemistry of recurvatiane A was established by derivatization with (R)- and (S)-α-methoxy-α-phenylacetic acids (MPA). The suite of guaiane-based metabolites here reported, which we have named recurvatianes A-F, provide an example of a pathway by which molecular diversity is generated by the occurrence of specific oxidation reactions in the late biosynthetic steps of the frame structure.

Effects of UV-B radiation in morpho-genetic characters of Gnaphalium luteo-album.

Genetic analyses of Gnaphalium's DNA showed a high degree of polymorphism in UV-B irradiated plants when compared to controls. Among the five tested primers the four ISSR primers selected for this analysis generated a total of 189 fragments. A high proportion of polymorphic bands ranging from 70% to 28% were found using these ISSR markers.

Pronuciferine N-oxide, a proaporphine N-oxide alkaloid from Berberis coletioides.

Pronuciferine N-oxide (1), a proaporphine N-methyl-N-oxide alkaloid, along with the parent alkaloid pronuciferine (2) were isolated from Berberis coletioides. The structure of the new compound was determined by spectroscopic evidence. Compound 1 is the first naturally occurring proaporphinoid alkaloid with an N-oxide functionality.

Biological activity of some Patagonian plants.

Citotoxicity (inhibition of cell division in fertilized eggs of Loxechinus albus) and general toxicity (using embryos of Artemia salina) of plants belonging to the genera Senecio, Deschampsia, Alstroemeria, Anarthrophyllum, Chloraea and Geranium were investigated.

Effects of UV-B radiation on the Patagonian Jaborosa magellanica Brisben.

Treatment of Jaborosa magellanica with artificial UV-B radiation caused changes in plant growth, plant chemistry and increase DNA polymorphisms. Spectrophotometric analysis showed that UV-B radiation decreases the chlorophylls content, and increases the amount of UV-B absorbing compounds (e.g.