Bestimmung des isoelektrisch fällbaren Proteins aufgeschlossener Mikroorganismen mittels Coomassiebrillantblau G-250

An analytical method for a rapid determination of the protein dissolved from microorganisms after cell disintegration and protein extraction is presented, thereby distinguishing both the isoelectrical precipitable and the isoelectrical nonprecipitable protein fraction. The method is especially usefull for controlling disintegration and protein extraction steps in production of protein isolates from microbial biomasses.     

Rapid interorgan communications in higher plants with special reference to flowering

Several examples of transmission of rapid signals within plants are described. Most of these signals may be inhibited by pretreating plants with LiCl, with inhibitors of ionic permeability, or with substances interfering with Ca²⁺. Accordingly, they are dependent on ionic changes. LiCl also prevents or delays the onset of flowering in long-day plants. In addition isolated organs or tissues most often do not react to an external stimulus as do similar organs or tissues within an intact plant. All these facts lead to the conclusion that plants are highly integrated organisms. Any change in the ionic equilibrium occurring in one part of these organisms has rapid consequences in other parts. This hypothesis may be applied to the floral process: after perception of the appropriate environmental conditions, the leaves modify the orientation of meristem differentiation by promoting the redistribution of ions (especially Ca²⁺, which has a “second messenger” function).     

Expression and release of phosphatidylinositol anchored cell surface molecules by a cell line derived from sensory neurons.

Early postnatal mouse dorsal root ganglion neurons were found to express several glycosylphosphatidylinositol-anchored (GPI) molecules from the immunoglobulin superfamily (neural cell adhesion molecule 120 kD isoform, F3, Thy1) whose expression is developmentally regulated. A hybrid cell line (ND26), made by fusing postmitotic rat dorsal root ganglion (DRG) neurons with the mouse neuroblastoma N18Tg2, could be induced to differentiate by manipulating the composition of the culture medium and expressed similar GPI molecules to DRG neurons. We used this model system to investigate the metabolism of GPI-anchored molecules. We found that neural cell adhesion molecule 120 Kd isoform expression decreased upon differentiation, whereas the level of F3 and Thy1 increased, suggesting a role in neurite outgrowth processes. The ratio of molecules cleavable by exogenous phosphatidylinositol phospholipase C (PI-PLC) was similar for all the GPI-anchored molecules, which could mean that cell-specific modifications of the basic anchoring structure determine the level of potentially releasable molecules. Measurements of spontaneous release indicated that this reflected the overall level of expression of these molecules by the ND26 cell line. Finally, we observed an effect of dibutyryl cAMP on the level of expression of F3 and Thy1 but not of N-CAM. However, we could not detect any significant effect of nerve growth factor (NGF) either on the level of expression or on the amount of spontaneously released molecules.     

Ten types of microscopically identifiable airborne fungal spores at Leiden,The Netherlands

A universal method for the complete assessment of atmospheric fungal spores does not exist, which is continuous, volumetric and non-selective, and offers at the same time reliable identification of the collected spores. To perform a survey of airborne fungal spores, a choice has to be made between a viable and non-viable method. For the study carried out in Leiden, the non-viable, continuous volumetric method has been employed, showing the results over a period of 10 years, for 10 microscopically identifiable fungal spore types. Of this selection,Cladosporium spores have by far the highest airborne quantities, with an average annual total of the daily averages of over 700 000.Botrytis, Ustilago andAlternaria follow with much lower spore concentrations of between 20 000 and 30 000 as annual totals. The spore types ofEpicoccum, Erysiphe, Entomophthora, Torula, Stemphylium, andPolythrincium are represented with annual sums lower than 10 000. A spore calendar shows the overall seasonal appearance of the 10 selected types.     

Evaluation of Comparative DNA Amplification Fingerprinting for Rapid Species Identification within the Genus Clusia

Understanding the taxonomiy of the tropical genus Clusia (Fam. Clusiaceae, Ord. Theales) has been hampered by the difficulties inherent in studying tropical dioecious, succulent, arborescent, epi- or hemiepiphytic taxa. Species identification by morphological traits often requires the terminal inflorescences and/or the succulent capsular fruits. To allow species differentiation based exclusively on vegetative tissue, a frequent necessity during ecological field studies, a procedure has been developed for rapid isolation of genomic DNA from Clusia leaf tissue followed by DNA amplification fingerprinting with a set of single arbitrary oligomer primers (23–27 mers). Fingerprints obtained with independent DNA preparations from one individual as well as DNA preparations from several individuals of the same species were identical for the major amplification products, although minor bands were somewhat variable. Polymorphic fingerprints have been obtained with 3 different primers for 3 Clusia species (C. minor L., C. alata Pl. & Tr., C. multiflora H. B. K.), and the related Oedematopus obovatus Spruce ex. PL (Clusiaceae). The interspecific Randomly Amplified Polymorphic Markers (RAPDs) thus obtained allow a rapid identification of vegetative tissue samples collected in the field, and will assist in a revision of the controversial taxonomy of the genus Clusia.     

Untersuchungen über den Membraneffekt des Absorptionsgewebes und Über die Farbstoffaufnahme in die Lebende Zelle

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