G. Tedesco

Characterization of the major proteins from Vitis vinifera seeds

Abstract The major protein from the endosperm of Vitis vinifera cv. Chardonnay is a globulin, homogeneous by size ( M τ ⩾ 400 kD after PAGE) and highly heterogenous by charge, 23 bands being resolved by IEF, with pI values 4.8–5 for the major components, and up to pH 7 for the minor ones. The native structure is assembled from non-covalently bound subunits, with M r which in turn are composed of disulfide-bridged peptides, M τ 19–21 kD and 38–44 kD. The focusing pattern of the denatured protein includes 15 acidic (pI values = 4.25–4.8) and two alkaline ( M τ = 26 kD, pI = 6.8–6.9) components. None of the major bands contains sugar or lipid mojeties. Several enzymatic activities are detected: esterase, phosphoglucomutase, acid phosphatase, peroxydase, malic, alcohol and a little lactic dehydrogenase; no protease inhibitors can be identified. The quali-quantitative variability among proteins extracted from individual seeds amounts to approx. 10%; only large samples, including 20–30 seeds, are thus likely to be representative of the genetic set-up of a given Vitis clone.

Considérations sur l'Anatomie dePosidonia oceanica (Zosteraceae)

The rhizome ofPosidonia oceanica shows an arrangement of vascular tissue not yet observed in other plants: a series of vascular cylinders all laid out in a single plane. There is a central cylinder, an atactostele, and six lateral cylinders, three on each side. These lateral cylinders are quite unusual too, each of them being formed by a single perixylematic bundle. For these structures the authors suggest the term haploendoleptostele; the whole arrangement might be called xestomeristele.

An electrophoretic approach to Basidiomycetes taxonomy: Intraspecific variability, varieties, ecological influences

Abstract Basidiospores of several Basidiomycetes species were treated with electrophoretic techniques, comparing the different protein fractions of the soluble component of the spores wall. The electrophoretic data were elaborated to obtain dendrograms indicating the similarity degree. The method was set up and tested for its validity. The technique showed that the degree of variability within the observed species escaped any generalization, covering a broad range; it was possible to identify the varieties in dendrograms of species grown in the same/different geographical zones; the growing environment and the symbiotic host often influenced the electrophoretic pattern of the spore wall proteins and resulted in dendrograms reflecting the ecological conditions. Abbreviations: ACP, acid phosphatases; EST, esterases; UPGMA, unweighed pair‐group method using arithmetical average

Proteins and chlorophyllase activity in Hedera helix L. with green or variegated leaves

Abstract Chlorophyllase activity and photosynthetic membrane proteins of two lots of Hedera helix were studied. Both the HV variety with variegated leaves and HC variety with green leaves were observed. Proteins from green, white and white-green portions of leaves differing in age were compared using dodecyl-sulfate-polyacrylamide gel electrophoresis. The white or white-green regions of Hedera helix var. aureomarginata (HV) did not differ significantly in chlorophyllase activity.