Fatty acid content during reconstitution of the photosynthetic apparatus in the air-dried leaves of Xerophyta scabrida after rehydration

Desiccation of Xerophyta scabrida caused considerable damage of chloroplast ultrastructure together with a complete loss of chlorophyll. Upon rehydration, the relative water content of the pale-green leaves almost reached that of the dark-green ones, however, the Chl content and photosynthetic activity remained lower. The process of reconstitution of the photosynthetic apparatus in the re-greening leaves was accompanied by changes in fatty acid (FA) content. The amount of the FA methyl esters was more than 2-fold higher in the green leaves as compared to the dry ones and slightly increased after rehydration in the pale-green leaves. Among the three main fatty acids in the leaves, oleic, palmitic and linoleic acid, the latter increased more than 3-fold during rehydration. This acid is concentrated mainly in the glycolipids and this was an indirect indication for the restoration of the photosynthetic apparatus. Our results showed that rehydration of X. scabrida led to a decrease of the saturated FA in parallel with an increase of the unsaturated FA, thus indicating increased membrane permeability. The observed changes in the lipid content can be considered as a characteristic feature of X. scabrida and most probably of other poikilochlorophyllous species.     

Chemical composition of the sponge Chondrosia reniformis from [2pt] the Canary Islands

Lake Zempoala was studied throughout 16 months in 1996–1997. It is a shallow monomictic lake situated at 2800 masl at the Neovolcanic Belt, well within the Mexican tropical zone. Most of the phytoplankton species in this lake may be characterized as temperate, according to their geographical distribution. A break down in phytoplankton biomass was observed before the lake's circulation, and open to question if a clear-water phase could be present in a tropical lake.     

Vitamin D-dependent protein of smooth endoplasmic reticulum membranes of rat enterocytes

DEAE-cellulose chromatography and SDS-PAAG electrophoresis were used to study proteins from endoplasmic reticulum of smooth and rough enterocyte membranes in the vitamin D-replete and deficient rat. The membrane-bound vitamin-D-dependent protein with a molecular weight of 21-25 kDa is shown to consist of the endoplasmic reticulum of smooth membranes. The intensive binding of calcium by these membranes is established.