Die auswirkungen der körpergrösse von Aphelinus semiflavus howard (HYM., Aphelinidae) auf einige Organe und ihre leistungsfähigkeit

Zusammenfassung Die Körpergröße von Aphelinus semillavus How. variiert in Abhängigkeit von Große und Qualität des Wirtes. Tiere aus dem gesamten Variationsbereich wurden auf größenabhängige Proportionsverschiebungen untersucht.Relative Länge und Breite des Kopfes (bezogen auf die Körperlange) nehmen mit zunehmender Körperlange ab. Die relative Lange des Abdomens wächst etwa um den gleichen Betrag:Es besteht eine negative Korrelation zwischen der relativen Länge des letzten Fühlergliedes, des Trägers wichtiger Sinnesorgane, und der Körperlange. Seine Oberfläche steht in einem etwa konstanten Verhältnis zur Körperlänge. Die Anzahl der Porenplatten nimmt mit der Körperlänge nur wenig, ihre Länge deutlicher zu.Im Komplexauge wächst die Anzahl der Ommatidien etwa proportional zur Korperlange, während seine gesamte Fläche zwar linear, aber ïiberproportional ansteigt, was durch zunehmende Große der einzelnen Facetten erreicht wird.Die Länge der Vorderfliigel ist bei Männchen und Weibchen von mehr als 1 mm Länge etwa der Körperlange proportional. Unterhalb 1 mm nimmt die relative Flügellänge mit der Körperlange ab, bis die Flügel nur noch funktionslose Rudimente bilden. Die Relation Flügel-fläche:Körpergewicht ist bei mittelgroßen Tieren am günstigsten.Jedes Ovar hat stets drei Ovariolen, unabhängig von der Körperlänge. Große Weibchen legen nur etwas größere, aber bedeutend mehr Eier als kleine. Die Anzahl der (am 7.–10. Lebenstag) täglich abgelegten Eier steigt etwa linear mit dem Logarithmus des Körpergewichts an.Die Eiablage wird während des ganzen Lebens (im Labor etwa 40 Tage) fortgesetzt, ist aber zum. Ende hin etwas geringer. Relativ zum Körper-gewicht produzieren mittelgroße Weibchen die größte Eimasse. Die Anzahl der zum Nahrungsgewinn ausgesaugten Läuse steigt mit dem Körpergewicht.Zwischen der relativen Länge des Legestachels und der Körperlange besteht eine fast lineare negative Korrelation.Die gröBenabhangigen Proportionsverschiebungen werden als Auswirkungen unterschiedlicher Wachstumstendenzen der einzelnen Organe gedeutet, die ihrerseits genetisch fixiert sind und den biologischen Sinn haben, die Lebensf ähigkeit modifikatorisch kleiner Exemplare zu sichern und damit die Ausnutzung entsprechend kleiner Wirte zu ermöglichen.Die Bedeutung der Proportionsverschiebungen für die Leistung der ganzen Population wird diskutiert. Sic ist abhängig von der Häufigkeits-verteilung der verschiedenen Körpergrößen und these wiederum von der Art-Zusammensetzung und Ernährung der Wirtsfauna.

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Summary The body size of Aphelinus semiflavus How. varies with the size and the quality of the hosts. Specimens from the whole range of variation were investigated for differences between organ proportions, which depended on size.The relative length and width of the head (based on the body length) are reduced with increasing body length. The relative length of the abdomen increases approximately by the same amount.There is a negative correlation between the relative length of the last joint of the antennae and the body length. Its surface shows a nearly constant proportion to the body length. The length of the pore plates increases with the body length more distinctly than their numbers.Within the compound eye, the number of ommatidia increases almost proportionally to the body length; the whole area of the eye increases more than proportionally because the size of the single facets also becomes greater.When the body length is greater than 1 mm, the length of the forewings is nearly proportional to the body length. At less than 1 mm, the relative length of the fore-wings is reduced with declining body length until, finally, only rudiments without any function remain. The ratio between wing area and body weight is most favourable at medium body size.Three ovarioles, independent of the body size, are present in each ovary. Big females produce considerably more eggs than small ones. The size of their eggs is only slightly enlarged. The daily egg production (at the 7^th–10^th day of life) increases nearly linearly with the logarithm of body weight. Oviposition is continued throughout the life-time of the insect (ca. 40 days in the laboratory) but it is somewhat reduced at the end. Relative to their body weight, females of medium size produce the biggest egg masses. The number of aphids utilized by the parasite for nourishment increases with the body weight of the female.A negative correlation exists between the relative length of the extended ovipositor and the body length.The proportion differences of the organs, dependent on size, are interpreted to be consequences of different growth tendencies which are genetically fixed. Apparently, the biological role of such different growth tendencies is to ensure the viability of phenotypically small specimens and in this way to make the utilisation of small hosts possible.The importance of the differences of body proportions for the effect of the whole population is discussed. It depends on the frequency distribution of the different body lengths which itself is the consequence of the composition of host species and the nutriation of the hosts.

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Herrn Prof. Dr. Hans Braun, emer. Direktor des Instituts für Pfanzenkrankheiten an der Universität Bonn, zu seinem 70. Geburts'ag am 2. Februar 1966 gewidmet.     

Direct effects of serotonin and ketanserin on the functional morphology of embryonic chick skin in vitro

Summary Different organotypical culture methods are used to test the direct effects of serotonin and ketanserin, a S₂, α₁, and H₁ receptor antagonist in vascular tissue, on fibroblasts and epidermal cells of embryonic chick skin in vitro. From light microscopic and electron microscopic analyses, we learn that serotonin enhances keratinization and differentiation, whereas ketanserin reduces differentiation in comparison to the control cultures. Incorporation data of fragments cultured with [³H]thymidine show that ketanserin, within a dose range from 0.05 to 5 μg/ml, stimulates proliferation. Serotonin at a concentration of 10 μg/ml slightly slows down proliferation, whereas lower doses of 0.1 and 1 μg/ml result in tritium activities that do not differ from control cultures. This investigation was financially supported by the National Fund of Scientific Research, Belgium, 3.0022.87.     

Rabbit distal colon epithelium: III. Ca2+-activated K+ channels in basolateral plasma membrane vesicles of surface and crypt cells

Summary In the mammalian distal colon, the surface epithelium is responsible for electrolyte absorption, while the crypts are the site of secretion. This study examines the properties of electrical potential-driven⁸⁶Rb⁺ fluxes through K⁺ channels in basolateral membrane vesicles of surface and crypt cells of the rabbit distal colon epithelium. We show that Ba²⁺-sensitive, Ca²⁺-activated K⁺ channels are present in both surface and crypt cell derived vesicles with half-maximal activation at 5×10^–7 m free Ca²⁺. This suggests an important role of cytoplasmic Ca²⁺ in the regulation of the bidirectional ion fluxes in the colon epithelium.The properties of K⁺ channels in the surface cell membrane fraction differ from those of the channels in the crypt cell derived membranes. The peptide toxin apamin inhibits Ca²⁺-activated K⁺ channels exclusively in surface cell vesicles, while charybdotoxin inhibits predominantely in the crypt cell membrane fraction. Titrations with H⁺ and tetraethylammonium show that both high-and low-sensitive⁸⁶Rb⁺ flux components are present in surface cell vesicles, while the high-sensitive component is absent in the crypt cell membrane fraction. The Ba²⁺-sensitive, Ca²⁺-activated K⁺ channels can be solubilized in CHAPS and reconstituted into phospholipid vesicles. This is an essential step for further characterization of channel properties and for identification of the channel proteins in purification procedures.     

Linkage analysis of the Duffy blood group marker with several chromosome 1 genes in an extended pedigree with Charcot-Marie-Tooth disease

Summary We have recently demonstrated tight linkage of the Duffy blood group marker to the -spectrin gene in an extended pedigree with Charcot-Marie-Tooth neuropathy. To determine a more precise location of the Duffy blood group locus on the chromosome 1 map we have tested several more chromosome 1 genes for linkage with this marker. We found suggestive linkage with the antithrombin III and apolipoprotein A2 genes and conclusive linkage with the gene coding for -nerve growth factor.     

Re-evalution of “Typothorax”meadei,a Late Triassic aetosaur from the United States

Aetosaur specimens from Howard County, Texas, USA, namedTypothorax meadei by Sawin (1947) represent a new genus here namedLongosuchus (type and only species -L. meadei). Longosu-chus is characterised by the possession of seven dentary teeth, a dentary excluded from the ventral margin of the lateral mandibular fenestra and by the angular, spinose lateral scutes throughout the dorsal region with lateral horns which have faceted sides.Longosuchus is found in mid-late Carnian strata in Texas, New Mexico and North Carolina, USA. Aetosaurs can be used to distinguish three successive biochrons in Late Triassic strata of the American Southwest, which are, in ascending order of age, theLongosuchus biochron, theStagonolepis biochron and theTypothorax biochron.     

Application of Asymmetric Alternating Voltage Pulse Series for Investigation of the Action Potential in Chara

An alternating (asymmetric) bipolar staircase voltage clamppulse series was used to investigate the action potential inChara corallina. Using this protocol, we found that the actionpotential was present in the hyperpolarized region of the current-voltagerelationship of the whole cell membrane. Effects of strong hyperpolarizingvoltage steps, during the excitation process, can thus be studied. (Received August 22, 1989; Accepted October 14, 1989)     

In Vivo and In Vitro Evidence for the Biosynthesis of Testosterone in the Telencephalon of the Female Frog

Abstract: Neurons and glial cells are capable of synthesizing various steroid hormones, but biosynthesis of testosterone in the CNS has never been reported. The aim of the present study was to demonstrate the synthesis of testosterone in the frog brain. The presence of 17β-hydroxysteroid dehydrogenase (17β-HSD)-like immunoreactivity was detected in a population of glial cells located in the telencephalon. Reversed-phase HPLC analysis of brain tissue extracts combined with radioimmunoassay detection revealed the presence of substantial amounts of testosterone and 5α-dihydrotestosterone (5α-DHT) in the telencephalon where 17β-HSD-positive cells were visualized. In male frogs, castration totally suppressed testosterone and 5α-DHT in the blood and in the rhombencephalon but did not affect the concentration of these two steroids in the telencephalon. Chemical characterization of testosterone in female frog telencephalon extracts was performed by coupling HPLC analysis with gas chromatography-mass spectrometry. Using the pulse-chase technique with [³H]pregnenolone as a precursor, the formation of a series of metabolites was observed, including dehydroepiandrosterone, androstenedione, testosterone, 5α-DHT, and estradiol. These data demonstrate the existence of an active form of 17β-HSD in the frog telencephalon, which is likely involved in testosterone biosynthesis within the brain.     

A proenkephalin A-derived peptide analogous to bovine adrenal peptide E from frog brain: Purification, synthesis, and behavioral effects

A peptide derived from the posttranslational processing of proenkephalin A was isolated from an extract of the brain of the European green frog Rana ridibunda and its primary structure established as: Tyr-Gly-Gly-Phe-Met-Arg-Arg-Val-Gly-Arg¹⁰-Pro-Glu-Trp-Trp-Gln-Asp-Tyr-Gln-Lys-Arg²⁰-Tyr-Gly-Gly-Phe-Met. The structure was confirmed by chemical synthesis. The peptide represents an amphibian equivalent of bovine adrenal peptide E [preproenkephalin A (206–230)-peptide] but the sequence contains two amino acid substitutions (Met¹⁵ → Gln and Leu²⁵ → Met) compared with the mammalian peptide. The data support previous hypotheses that the Leu-enkephalin sequence is not present in preproenkephalin A of amphibians. Intracerebroventricular injections of frog peptide E (10 and 100 ng) in mice had no significant effect on horizontal locomotor activity. The peptide, in doses up to 1 μg, had no effect on latency of escape jumping in the hot plate test and the peptide (100 ng) did not modify responses (paw licking, rearing, and escape jumping) in morphine-treated mice.