Alicia M. Seldes

BLUE PIGMENTS IN SOUTH AMERICAN PAINTING (1610–1780)

AbstractThis article shows the results reached by an interdisciplinary team of chemists and art historians following studies of the use of blue pigments in a group of 106 paintings done in the Andes region during the colonial period (1610–1780). It describes the methods employed and the results obtained in the analysis of these pigments, along with important observations on the historical dimension of the practices developed by South American artists of that period.

GREEN, YELLOW, AND RED PIGMENTS IN SOUTH AMERICAN PAINTING, 1610–1780

Abstract A multidisciplinary team of chemists and art historians from the University of Buenos Aires and the National Council of Scientific and Technological Research (CONICET) has examined the green, yellow, and red pigments used in a collection of 29 paintings from the highlands of Peru in the Andean region during the colonial period (1610–1780). The results described in this paper are a continuation of previous research on blue pigments found in the same corpus (JAIC 38[1999]: 100–23). The results show how the artists from the big workshops of Cusco and the cities of the Alto Peru (the highlands of Bolivia and N.W Argentina) followed the recipes for color preparation included in the technical treatises written by Spanish painters. Once again, the figure of Mateo Pisarro, an artist active in the Puna of Atacama at the end of the 17th century, emerges as an exceptional investigator of color-rendering problems.

A 3,4-seco-cycloartane derivative from Tillandsia usneoides

Abstract From Tillandsia usneoides a new 3,4- seco -cycloartane has been isolated and identified by spectroscopic methods as dimethyl3,4- seco -cycloart-4(29), 24 E -diene-3,26-dioate.

Anasterocerebroside A, a New Glucosylceramide from the Patagonian Starfish Anasterias minuta

Abstract Eight glucosylceramides (1-8) were isolated from the water-insoluble lipid fraction of a methylene chloride/methanol/water extract of the Patagonian starfish Anasterias minuta. One of the constituents was identified as a new glucosylceramide, anasterocerebroside A (1), while the known glucosylceramide 7 was isolated and characterized for the first time as a pure compound. The structures of 1 and 7 were established by spectroscopic and chemical methods.

Sulfated Polyhydroxysteroids from the Antartic Ophiuroid Gorgonocephalus Chilensis

Five disulfated steroids and a mixture of monosulfated steroids were isolated from the ethanolic extract of the antarctic ophiuroid Gorgonocephalus chilensis. The structures were determined by 1H-NMR, 13C-NMR and FABMS.

MAIN STEROLS FROM THE OPHIUROIDS OPHIOCOMA ECHINATA, OPHIOCOMA WENDTII, OPHIOPLOCUS JANUARII AND OPHIONOTUS VICTORIAE

Abstract Sterol compositions of the cold water ophiuroids Ophioplocus januarii and Ophionotus victoriae and of the tropical ophiuroids Ophiocoma echinata and Ophiocoma wendtii are reported. The four sterol mixtures contain Δ 5 mono- and di-unsaturated common 3β-hydroxy-sterols. Ophioplocus januarii and O. victoriae contain 24-methylcholesta-5,24(28)-dien-3β-ol and 24ζ-ethylcholesta-5,24(28)-dien-3β-ol in higher abundance than in O. echinata . These sterols were not found in O. wendtii . An interesting finding is the presence of Δ 5,24(28) -24- n -propylidenecholesterol in 7.6% in Ophionotus victoriae .