Kurze Mitteilungen

Zusammenfassung Ein Paar Türkentauben brütete vom 29. 1. bis 15. 2. 1966 auf einem Straßenbaum in Berlin-Tempelhof. Es wurde nur ein Ei gelegt. Nach 17 Tagen schlüpfte das gelbbedaunte Junge. Es ist dann kurz danach, wahrscheinlich beim Umherkriechen auf dem Nestrand, erfroren. Die Umstände, unter denen die Brut erfolgte, waren äußerst ungünstig. Die Temperatur lag seit dem 7. 2. 1966 dauernd unter Null (–9 und –13 Grad). Die brütende Taube hatte von Anfang an auf dem Nestrand brüten müssen, da die Mulde schon vor der Eiablage völlig mit Schnee bedeckt war. Der brütende Vogel war mehrere Tage und Nächte von einem hohen Schneewall umgeben, der sich auf dem Nest gebildet hatte. Dieses Nest wurde von Mai 1964 an viermal von einem Türkentaubenpaar zum Brüten benutzt. Es wird vermutet, daß zum mindesten der eine Partner, der Tauber, während der ganzen Zeit derselbe geblieben ist.     

Über die histochemische Erfassbarkeit der Aminosäure-Dehydrogenasen in Säugetierorganen

Summary A study was conducted in order to contribute to the methodology and topochemical localization of amino acid dehydrogenases in mammals; Nitro-BT, Tetra-Nitro-BT and phenazine methosulphate were used in the tests. Under anaerobic incubation conditions varying amounts of some -amino acids (dextrorotators) are oxidized in the mammalian kidney. The positive test result is regarded as the manifestation of a d-amino acid dehydrogenase activity. The investigation reveals that the kidney of carnivores (cat, dog, mink) shows the highest d-AAD-activity. However, this activity is histochemically not detectable in the kidney of genuine herbivores (guinea pig, rabbit, cattle). Rat, mouse, pig, and sheep take an intermediate position. In most of the species investigated the oxidative deamination of the d-amino acids takes place in the pars recta (renal cortex). In humans and sheep, however, the entire renal cortex gives positive results. The reaction is negative in the liver of most of the species tested.Out of the l-amino acids, tested in the course of the investigation, it is only l-proline that gives a positive result on kidney sections. In contrast to the findings concerning d-AAD activity, the formazan deposits are seen in the pars convoluta. In all probability this activity can bei regarded as a specific proline-dehydrogenase.Zusammenfassung Es wurde der Versuch unternommen, zur Methodik sowie zur topochemischen Lokalisation der Aminosäure-Dehydrogenasen beim Säugetier unter Verwendung von Nitro-BT bzw. Tetra-Nitro-BT und Phenazinmethosulfat beizutragen. Unter anaeroben Inkubationsbedingungen werden dabei einige -Aminosäuren der d-Reihe in unterschiedlicher Rate in der Säugerniere oxydiert und der positive Reaktionsausfall als Ausdruck einer d-Aminosäure-Dehydrogenaseaktivität angesehen. Wie die Untersuchungen ergaben, zeigt die Niere von Carnivoren (Katze, Hund, Nerz) die stärkste d-ASD-Aktivität, während die Aktivität in der Niere reiner Herbivoren (Meerschweinchen, Kaninchen, Rind) histochemisch nicht faßbar ist. Ratte, Maus, Schwein und Schaf nehmen eine Zwischenstellung ein. In der Nierenrinde der meisten untersuchten Tierarten findet die oxydative Desaminierung der d-Aminosäuren vorwiegend in der Pars recta der Hauptstücke statt; bei Schaf und Mensch zeigt die gesamte Nierenrinde einen positiven Reaktionsausfall. An der Leber der meisten untersuchten Arten war die Reaktion negativ.Von den getesteten l-Aminosäuren konnte nur mit l-Prolin ein positiver Befund an Nierenschnitten erhoben werden. Im Gegensatz zur d-ASD finden sich die Formazanablagerungen bei den meisten untersuchten Spezies in der Pars convoluta der Hauptstücke. Auf Grund der Untersuchungen wird angenommen, daß es sich hierbei um eine spezifische Prolin-Dehydrogenase handelt.     

Image analysis of restriction enzyme fingerprint autoradiograms

A genome mapping system has been developed that reads and assemblesdata from clones analysed by restriction enzyme fragmentationand polyacrylamide gel electrophoresis. Input data for the systemcan be most effectively obtained by the use of a scanning densitometerand image-processing package, such as that described in thisarticle. The image-processing procedure involves preliminarylocation of bands, cooperative tracking of lanes by correlationof adjacent bands, a precise densitometric pass, alignment ofthe marker bands with the standard, optional interactive editing,and normalization of the accepted bands. Received on August 31, 1988; accepted on December 6, 1988     

Establishment of microscale vegetation pattern in maritime chaparral after fire

We quantified microscale pattern in vegetation and seed assemblages along a 24 m transect before and for two years following a controlled burn in chamise (Adenostoma fasciculatum) chaparral in central coastal California. Our objective was to document scale-dependent correlation between pre-burn seed assemblages, pre-burn canopy cover, microtopography, soil temperatures during burning, post-burn seed assemblages and post-burn vegetation. Scale-dependent correlations among pre- and post-burn seed densities, maximum soil temperatures during burning, microtopography and post-burn vegetation were measured based on two-term local covariance analysis.Seed distribution varied among species prior to fire, with seeds of some annual species concentrated in gap areas. Maximum soil temperatures during burning ranged from less than 50 °C to 225 °C, and were generally lowest in gaps in the pre-burn canopy. These gaps were associated with local topographic depressions. After burning, readily germinable seeds were concentrated in or near gaps in the pre-burn canopy. Germination of different species was variously enhanced, diminished or unchanged by the passage of fire. Post-burn vegetation was very patchy, with some areas nearly devoid of seedlings and other areas, especially pre-burn canopy gaps, supporting numerous seedlings. Seedling recruitment patterns in the second year were generally highly correlated with patterns in pre-burn seed banks and first year vegetation. Although many species exhibited similar recruitment patterns, several different mechanisms may have been responsible for the origin of those patterns.     

Diphtheria-tetanus overimmunization in children with no records: can it be prevented?

A pilot study was undertaken to assess the validity of two new tests for predicting the immune response of Toronto schoolchildren with no acceptable evidence of prior administration of diphtheria or tetanus toxoid to a routine booster injection of diphtheria and tetanus (DT) toxoid. The tests, an inexpensive enzyme-linked immunosorbent assay (ELISA) fingerprick test for tetanus antibodies and a modification of the Schick skin test for susceptibility to diphtheria, were administered before the booster injection. One week later the ELISA test was repeated and the result of the modified Schick test read. On both occasions a diphtheria microneutralization assay was done for "gold standard" evidence of prior exposure to diphtheria toxoid or toxin. The results were used to determine the sensitivity and specificity of a single prebooster tetanus ELISA test or a modified Schick test for predicting which children with no records could be safely protected with only one DT booster dose instead of the primary series of three or four doses usually given to such children. Only 6 of the 34 subjects (18%) were totally without prior exposure to tetanus toxoid. Two of the six (6% of 33 subjects) appeared to mount a primary immune response to diphtheria toxoid as well. An initial ELISA titre of 0.01 IU/ml or lower correctly identified all six children needing a full series of tetanus toxoid (sensitivity for a primary immune response 100%) and falsely identified only 3 of 28 immune children as needing the series (specificity for immunity 89.3%). The modified Schick test appeared to have even greater accuracy for identifying children needing a full series of diphtheria toxoid. However, its use, entailing the costs of an extra nurse visit, would have prevented only seven more children from receiving an unnecessary full series of diphtheria toxoid than use of the baseline tetanus ELISA test alone.     

Neural cell recognition molecule F11: homology with fibronectin type III and immunoglobulin type C domains

We report here the complete cDNA sequence of F11 130 kd polypeptide, a chick neural cell surface-associated glycoprotein implicated in neurite fasciculation and elongation. The predicted protein sequence of 1010 amino acids includes an amino-terminal signal peptide and a carboxy-terminal hydrophobic stretch, which is compatible with the consensus motif for covalent attachment of glycosyl-phosphatidylinositol. Accordingly, F11 lacks an intracellular domain, which is consistent with evidence obtained from protease protection experiments on isolated microsomes. In addition, the molecule comprises six domains related to the immunoglobulin domain type C and four resembling fibronectin repeat type III. Both types of repeats resemble those present in neural cell adhesion molecules L1 and N-CAM. The possible identity of F11 with the chick neural glycoprotein contactin is discussed.     

Stimulation of Muscarinic Acetylcholine Receptors Increases Synaptosomal Free Calcium Concentration by Protein Kinase-Dependent Opening of L-Type Calcium Channels

In synaptosomes prepared from rat cerebral cortex, free cytosolic calcium concentration ([Ca2+]i) was measured using the fluorescent dye fura-2. Incubation of fura-2-loaded synaptosomes with carbachol increased [Ca2+]i in a dose-dependent manner (1-1,000 microM), with a maximum response of 22 +/- 2% at approximately 100 microM and an EC50 (calculated concentration producing 50% of the maximum response) of 30 microM. The effect of carbachol (100 microM) on [Ca2+]i was antagonised by atropine, but not by hexamethonium (10 microM). The calculated concentration of atropine needed for 50% inhibition (IC50) was 260 nM. The rise in [Ca2+]i produced by carbachol was reduced in the absence of extrasynaptosomal Ca2+ and effectively blocked by the L-type calcium channel blocker nifedipine (with an IC50 of 29 nM). The response to carbachol was reduced if the synaptosomes were preincubated with the protein kinase inhibitors H7 [1-(5-isoquinolinylsulfonyl)-2- methylpiperazine] (from 17% in the solvent control to 4%) and staurosporine (from 20% in the solvent control to 3%). These results show that stimulation of muscarinic acetylcholine receptors in synaptosomes increases [Ca2+]i by protein kinase-dependent activation of 1,4-dihydropyridine-sensitive calcium channels.