Hasel-Pollengehalt der Luft in Mitteleuropa

Jahreszeitliche und tageszeitliche Veränderungen des Haselpollengehalts der Luft nach Untersuchungen aus den Jahren 1967 bis 1972 an elf mitteleuropäischen Meßstellen. Vergleich mit einigen anderen europäischen Daten über den Haselpollengehalt der Luft. In Mitteleuropa kamen die meisten Haselpollen zu Beginn oder gegen Ende des Monats März vor. Stündliche Höchstwerte wurden in den Tag- und Abendstunden gemessen. Morgens kamen keine hohen Stundenwerte vor. Temperaturmessungen lassen vermuten, daß für hohe Haselpollengehalte der Luft in Norddeutschland höhere Temperaturen nötig sind als in südwestdeutschen Gebieten.     

Model interpretation of visual-vestibular interaction in patients with labyrinthine and cerebellar pathologies

Oculomotor responses to combined optokinetic and vestibular stimulations in labyrinthine and cerebellar defective patients are discussed in terms of parametric changes in a model describing the interaction between the vestibulo-ocular reflex (VOR) and the optokinetic reflex (OKR). By making a few reasonable hypotheses about model parameter variations in relation to the type of pathology, the experimental results obtained by several authors can correctly be predicted and explained by the model. The model can therefore be used to define a set of parameters giving an estimate of the state of the system subserving VOR-OKR interaction in the examined patients. The model is also shown to be a powerful tool to assess the validity and the diagnostic significance of the procedures used to test VOR-OKR interaction.Work supported by CNR, Rome, Italy. Some results reported in this paper have been previously presented at the Eighth Extraordinary Meeting of the Bàràny Society, Basle, June 22th-25th, 1982.     

The organization of macronuclear DNA sequences associated with C4A4 repeats in the polytene chromosomes of Stylonychia lemnae

Gene libraries of the micronucleus and the macronuclear anlagen of the polytene chromosome stage of Stylonychia lemnae were screened for internal C₄A₄ repeats. The number of these internal repeats was shown to be identical in both kinds of nuclei. Analysis of macronuclear sequences associated with C₄A₄ in the polytene chromosomes showed that several macronuclear DNA sequences are clustered. However, interspersed between short exons of one gene are located exons of several other genes, i.e. the exon of one gene is an intron for several other genes.by M. Trendelenburg     

Early ventral expression of the Drosophila neurogenic locus mastermind

The neurogenic locus mastermind (mam) of Drosophila is required for the segregation of epidermal from neural cell lineages. Previous studies have shown that during neurogenesis mam appears to be expressed throughout the ectoderm, mesoderm, and neuroblast layer of the germ band. Here it is demonstrated that during early embryogenesis mam is expressed ubiquitously; however, the predominant domains of accumulation of mam RNA and protein during gastrulation are along the ventral longitudinal surface, including cells of the mesoderm, endoderm, mesectoderm, and neuroectoderm. The regions of elevated mam accumulation coincide with the realm of action of dorsoventral patterning genes.     

Comparative study of the structure/function relationship of wild-type and structurally modified maltopentaose-producing amylase.

Amylase A-180, which is secreted by a new alkaliphilic organism, isolate 163-26, consists of a single type of polypeptide chain of 186.5 kDa and hydrolyses starch by exo-attack releasing malto-pentaose as preferential product. The structure/function relationship of this unusual starch-degrading enzyme was analysed by introducing 3' deletions into the structural gene. It was found that removal of up to a 110-kDa portion from the C-terminus leaving 563 N-terminal amino acids still led to the formation of a fully active enzyme. The part of the structural gene coding for these 563 N-terminal amino acids was fused with the signal peptide-encoding segment of the cyclodextrin glucanotransferase gene from Klebsiella oxytoca and was cloned into an expression vector. The resulting truncated A-180 derivative, A-180/21, was efficiently transported through the cytoplasmic membrane and released into the medium by an Escherichia coli strain which 'leaks' periplasmatic components. A-180/21 was purified and its catalytic properties, i.e. specific activity and product specificity, proved to be identical to those of the wild-type enzyme; however, in contrast to the wild-type enzyme, it was unable to bind to raw starch and it displayed an altered temperature and pH dependence of activity.     

Cold hardiness of the green gemmules of Spongilla lacustris L. (Porifera: Spongillidae)

Most green gemmules of Spongilla lacustris survived enclosure in ice at –20 °C for up to 30 days; however, their rate of germination at 20 °C was less rapid than that of control gemmules. The length of time spent at low temperature had little effect on gemmule survival. In contrast, repeated cooling to –20 °C and warming to 4 °C led to a progressive decline in gemmule viability. These results indicate that cold injury occurs primarily during transitions between high and low temperatures.     

Cytosol- and clathrin-dependent stimulation of endocytosis in vitro by purified adaptors

Using stage-specific assays for receptor-mediated endocytosis of transferrin (Tfn) into perforated A431 cells we show that purified adaptors stimulate coated pit assembly and ligand sequestration into deeply invaginated coated pits. Late events in endocytosis involving membrane fission and coated vesicle budding which lead to the internalization of Tfn are unaffected. AP2, plasma membrane adaptors, are active at physiological concentrations, whereas AP1, Golgi adaptors, are inactive. Adaptor-dependent stimulation of Tfn sequestration requires cytosolic clathrin, but is unaffected by clathrin purified from coated vesicles suggesting that soluble and assembled clathrin pools are functionally distinct. In addition to adaptors and cytosolic clathrin other, as yet unidentified, cytosolic factors are also required for efficient coated pit invagination. These results provide new insight into the mechanisms and regulation of coated pit assembly and invagination.     

The complete primary structure of the boar spermadhesin AQN-1, a carbohydrate-binding protein involved in fertilization.

Gamete recognition and adhesion are essential steps in the complex process of fertilization. In mammals and in other species, increasing evidence indicates that carbohydrate-binding proteins on the sperm surface play a pivotal role as counter-receptors for certain oligosaccharide moieties attached to the oocyte zona pellucida glycoproteins. Although different sperm-associated zona-pellucida-binding proteins have been identified in a number of species, few of them have been isolated and structurally characterized. In this paper we report the primary structural characterization of AQN-1, a 12-kDa boar-sperm-associated carbohydrate-binding and zona-pellucida-binding protein. The molecular mass of AQN-1 was determined by time-of-flight plasma-desorption mass spectrometry. Determination of its amino acid sequence and location of disulphide bridges were accomplished by a combination of proteochemical and mass spectrometric methods. The primary structure of AQN-1 failed to show any significant similarity to the protein structures deposited with the Martinsried Institute for Protein Sequences data bank, indicating that it may belong to a novel protein family involved in fertilization. AQN-1 shares extensive structural, as well as functional, similarity with two other boar sperm zona-pellucida-binding proteins, AQN-3 and AWN, which we have recently characterized. To name this protein family, we have coined the term spermadhesin. Our data may be relevant for identification of spermadhesins in other species, and thus may contribute to a better understanding of the species-specific sperm-egg recognition mechanism.     

Purification and some properties of an extracellular l-amino acid oxidase from Cellulomonas cellulans AM8 isolated from soil

Summary The soil isolate Cellulomonas cellulans AM8 produces an extracellular l-amino acid oxidase (L-AAO) with broad substrate specificity. The strain produced up to 0.35 unit (U)/ml of the extracellular L-AAO in a simple medium containing glycerol and yeast extract. The enzyme was easily purified up to 30 U/mg protein using Phenyl-Sepharose fast flow. The purified enzyme migrated as single band on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) with a molecular mass of 55 kDa. On native PAGE the molecular mass was approx. 300 000 kDa, which may be due to aggregation. With the exception of glycine, proline, and threonine, all the amino acids normally constituting proteins were oxidized. The V _max values from 0.7 to 35.2 U/mg for aspartic acid and lysine, respectively, and the K _m values from 0.007 to 7.1 mm for cysteine and valine, respectively, were obtained at 25° C and pH 7.0 in oxygen-saturated solutions. The L-AAO had a pH optimum of 6.5–7.5. It was stable for several months at — 30° C and for some days at 35° C. Ferricyanide served as an electron acceptor with a V _max of 50 U/mg and K _m for 0.3 mm with phenylalanine as the substrate. Correspondence to: R. D. Schmid