BIOSYSTEMATIC STUDIES IN SEDUM OF TURKEY (CRASSULACEAE) .3. S-EUXINUM, A NEW SPECIES FROM NORTHEASTERN ANATOLIA

A new, yellow-flowered Sedum species is described from Turkey, S. euxinum. It is reported from three localities in the northeastern part of Anatolia. S. euxinum is classified in Sedum series Alpestria Berger. Its chromosome number is 2n = 48, but the species is considered to be diploid (x = 24). S. euxinum is regarded as a neo-endemic because of its high secondary basic number and restricted distribution at the periphery of the area of S. series Alpestria

BIOSYSTEMATIC STUDIES IN SEDUM (CRASSULACEAE) FROM TURKEY .4. THE CYTOLOGY OF SEDUM SUBSECT SPATHULATA BORISS

The diploid cytotypes of the species of Sedum series Involucrata and S. series Propontica of S. subsect. Spathulata differ more than five-fold in nuclear DNA amount, even though some occur in similar habitats and sometimes in mixed populations. Morphologically the two series are quite similar, but the basic chromosome numbers and karyotypes differ considerably, and they are probably only distantly related. The dysploid series in S. series Propontica, ranging from x = 7 to x = 5, is not a result of a simple series of successive Robertsonian translocations, but involves different kinds of chromosomal rearrangements as well. The 2C value of S. obtusifolium (x = 6) with the chromosome number 2n = 30 would indicate an octoploid (8x) level of ploidy, but the karyotype structure offers no explanation for the implicit loss of 18 chromosomes

ALKALOIDS OF SOME EUROPEAN AND MACARONESIAN SEDOIDEAE AND SEMPERVIVOIDEAE (CRASSULACEAE)

Some 22 pyrrolidine and piperdine alkaloids were detected in the leafy parts of Sedum acre, S. aetnense, S. anglicum, S. brissemoreti, S. farinosum, S. fusiforme, S. lancerottense, S. melanantherum, and S. nudum. In addition to the alkaloids known from S. acre, 1-(2-pyrrolidyl)-propan-2-one and 2-monosubstituted piperidine alkaloids bearing butan-2-one, butan-2-ol, pentan-2-one and pentan-2-ol sidechains were identified. Phenylethylamine was isolated from the vegetative parts of S. album. In S. lydium, S. meyeri-johannis, and 16 species of S. series Rupestria, Aeonium, Greenovia, Jovibarba and Sempervivum no alkaloids could be detected. The results indicate a correlation between the presence of alkaloids and the major evolutionary trends in the European and Macaronesian Crassulaceae

ALKALOIDS OF THE SEDUM ACRE-GROUP (CRASSULACEAE)

The 16 species of the Sedum acre-group were investigated for the presence of alkaloids. They are S. acre of S. ser. Acria, S. alpestre, S. annuum, S. apoleipon, S. borissovae, S. euxinum, S. grisebachii, S. laconicum, S. multiceps, S. sexangulare, S. tuberiferum, S. tuberosum, S. ursi, and S. urvillei of S. ser. Alpestria, S. samium of S. ser. Samia, and S. litoreum of S. ser. Litorea. S. acre differs significantly from the other species. It contains sedamine, ''hydroxy'' sedamine, and a number of 2,6-disubstituted piperidine alkaloids. The leafy parts of the species of S. ser. Alpestria, S. ser. Samia, and S. ser. Litorea contain 4 piperidine alkaloids which also occur in S. acre, and in addition 4 pyrrolidine alkaloids not present in S. acre. The composition of the alkaloid fraction agrees with the infrageneric classification (series) based on the hybridization patterns of the species (comparia)

EPICUTICULAR WAX COMPOSITION OF SOME EUROPEAN SEDUM SPECIES

Epicuticular waxes from 30 species of Sedum and 2 species of Sempervivoideae, i.e. Aeonium spathulatum and Sempervivum nevadense, have been analysed by GC and GC-MS. The Sedum taxa examined were S. acre, S. album, S. series Alpestria (13 species), S. anglicum, S. brevifolium, S. litoreum, S. lydium, S. series Macaronesia (four species), S. melanantherum and S. series Rupestria (five species) of S. sect. Sedum and S. meyeri-johannis of S. sect. Africana. The waxes consist of alkanes, alkanols, fatty acids, fatty acid methyl esters, aldehydes, wax esters and triterpenes. Some 14 triterpenes were detected in waxes of Sedum, the major triterpenes being beta-amyrenyl acetate, germanicyl formate (not previously reported from a natural source), multiflorenyl acetate and taraxeryl acetate. Waxes of the pruinose and glaucous taxa of Sedum were found to have a high triterpene content. In waxes of Aeonium spathulatum and Sempervivum nevadense, no triterpenes could be detected. Variation in the alkane and triterpene profiles proved to be of significant systematic value. In general, the distribution of the triterpenes in Sedum agrees with the infrageneric classification based on hybridization patterns and related morphological characters

An insulin receptor mutant (Asp(707)->Ala), involved in leprechaunism, is processed and transported to the cell surface but unable to bind insulin

We have identified a homozygous mutation near the carboxyl terminus of the insulin receptor (IR) alpha subunit from a leprechaun patient, changing Asp(707) into Ala, Fibroblasts from this patient had no high affinity insulin binding sites, To examine the effect of the mutation on IR properties, the mutant IR was stably expressed in Chinese hamster ovary cells, Western blot analysis and metabolic labeling showed a normal processing of the mutant receptor to alpha and beta subunits, No increase in high affinity insulin binding sites was observed on Chinese hamster ovary cells expressing the mutant receptor, and also, affinity cross-linking of I-125-labeled insulin by di-succinimidyl suberate to these cells failed to label the mutant alpha subunit, Biotinylation of cell surface proteins by biotin succinimidyl ester resulted in efficient biotinylation of the mutant IR alpha and beta subunits, showing its presence on the cell surface, On solubilization of the mutant insulin receptor in Triton X-100-containing buffers, I-125-insulin was efficiently cross-linked to the receptor alpha subunit by disuccinimidyl suberate