Yeast pheromone alpha-factor is synthesized as a high molecular weight precursor

The sex pheromone alpha-factor of Saccharomyces cerevisiae, a tridecapeptide of approx. 1,700 molecular weight, was found to be synthesized in vivo as a high molecular weight precursor of Mr = 28,000. Inhibition of N-linked glycosylation by tunicamycin leads to three precursor species of lower molecular weight indicating three carbohydrate residues linked to the alpha-factor precursor molecule. A molecular weight of 18,000 was determined for the unglycosylated molecule.     

Cholinesterase activity in some species of theAllium genus

In partly purified protein complexes obtained from 22 species of theAllium genus and 6 cultivars ofAllium cepa the activity of cholinesterases was detected and measured using the method of Ellman et al. The degree of its inhibition with 10^-4 M neostigmine was also tested. It was found that the activity of cholinesterase differed in individual species up to two hundred times, while the differences in the inhibitory activity of 10^-4 M neostigmine occurred only in a few cases. Individual sections and cultivars could not be characterized on the basis of the differences in the activities of the cholinesterases. Of all the sections that ofPhyllodolon shows the highest average activity. In the case of the tested cultivars distinctly the lowest activity was observed in cv. Kastická. The values of the enzymatic activity measured by Ellman’s method in this plant material include the activity of specific and unspecific cholinesterases and the part uninhibitable by neostigmine.     

Developmental changes in gene expression during pollen differentiation and maturation inNicotiana tabacum L

Total and polysome-bound ribosomes and the uptake and incorporation of³H-uridine and¹⁴C-leucine were examined in dividing microspores and in pollen grains isolated from anthers of 6 different developmental stages. Direct evidence was obtained that the formation of cytoplasm of the vegetative cell following microspore division is related to a rapid activation of RNA and protein synthesis and of ribosomes in differentiating pollen. Total ribosomes associated with gametophytic programme rose about 10times and the process of differentiation was accompanied by a rapid increase in uptake capacity of pollen grains for both uridine and leucine. Pollen development after cytoplasm synthesis and starch deposition continued by pollen maturation, which was characterized by a decline in RNA synthesis, dissociation of polysomes and by a further rise of transport activity of pollen grain wall for exogenous substrates, indicating probable pollen adaptation for utilization of metabolites from the degenerating tapetal cytoplasm.     

Comparison of malate dehydrogenase isoenzymes in someAllium species by isoelectric focusing

Malate dehydrogenase isoenzymes were studied in tenAllium species and in six cultivars ofA. cepa by isoelectric focusing in polyacrylamide gel with Ampholine pH 3.5–10.0. Using this method better resolution was obtained than by polyacrylamide gel electrophoresis. The number of MDH isoenzymes obtained by isoelectric focusing is from five to ten in the range of pH 3.65 to 6.75. MDH isoenzymes can be used for characterization on the level of species and cultivars (inA. cepa), but its use on the level of sections and subgenera is questionable.     

The comparison of seed protein patterns within the genusArachis by polyacrylamide gel electrophoresis

The seed protein patterns of 12Arachis species were compared by polyacrylamide gel electrophoresis (PAGE), similarities between patterns were measured by the Jaccard index. Results obtained confirm the close relationships established between members of the genus on morphological grounds and support the more recent classification schemes.A. villosa andA. correntina could well be regarded as distinct species on grounds of protein differences whileA. macedoi andA. villosulicarpa (although members of the same section, Extranervosae) show considerable differentiation of their protein patterns. Surprisingly, the formA. ×batizogaea showed less similarity in protein pattern to those of its parental species than might have been expected. The principle value of seed protein pattern data appears to be in distinguishing species within sections.     

Convenient,laboratory procedure for producing solid d-arabino-hexos-2-ulose (d-glucosone)

The production of solid d-arabino-hexos-2-ulose (d-glucosone) from d-glucose by use of an enzyme, pyranose-2-oxidase (EC 1.1.3.10), is described. The enzyme is extracted from the mycelia of Polyporus obtusus, partially purified, and then immobilized on activated CH-Sepharose 4B. The enzymic conversion of d-glucose into d-glucosone is simple and convenient, and provides a product free from residual d-glucose. Lyophilization of the filtered reaction-solution yields the product, solid d-glucosone. Assay methods have been developed for monitoring the enzymic reaction and evaluating the purity of the final product.     

Hilgendorf’s (1863) dissertation on the steinheim planorbids (Gastropoda; Miocene): The development of a phylogenetic research program for paleontology

Hilgendorf’s (1866) publication on the phylogenyof Planorbis multiformis from Steinheim, Swabian Mountains, is one of the most important contributions of paleontology to early Darwinism. At the same time it helped to lay the foundation for paleontological phylogenetics. Hilgendorf’s unpublished dissertation of 1863, the newly rediscovered collection to his dissertation and the document-file ofHilgendorf’s graduation from Tübingen University help to trace back the origin of Hilgendorf’s ideas.Hilgendorf’s collection contains the oldest phylogenetic tree, which is known so far.     

Foraminifers from the uppermost devonian and the dinantian of the rhenish massif (Federal Republic of Germany)

Foraminifers from typical Kulm environments are described from 4 localities at the eastern and northern border of the Rhenish Massif: aQuasiendothyra fauna of uppermost Devonian age (Famennian); a Chernyshinellinae fauna of the lower Dinantian Cf1 Zone (middle Tournaisian); upper Dinantian foraminifers from the Cf4δ to Cf6γ Zones (Middle and Upper Viséan). The foraminifer assemblages of the Cf6 Zone (V3b + c), in theGoniatites crenistria schmidtianus toNeoglyphioceras spirale Subzones, seem to be variegated in Germany and Belgium, but they are definitively poorer than contemporaneous faunes in the British Isles and the Russian Platform.