Ultrastruktur der Ovozyten vonOrnithodorus moubata,Murray (Ixodoidea:Argasidae) nach Triple-Fixation

Summary The triple-fixation (simultaneous fixation in a mixture of glutaraldehyde and osmium tetroxide and post-treatment in aqueous uranylacetate) is especially suitable for the demonstration of membranes and to distinguish different types of vesicles in the oocytes of the soft tickOrnithodorus moubata.

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Die Arbeit wurde vom Schweiz. Nationalfonds unterstützt.

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Frau S.Latscha-Stoller danke ich für ihre unentbehrliche technische Mitarbeit.     

Zum Proliferations-Stoffwechsel der Rattenleber nach Teilhepatektomie. Autoradiographische Untersuchungen mit3H-Cytidin,-Phenylalanin und -Thymidin

Summary During the first wave of parenchymal liver regeneration in adult rats after partial hepatectomy, the cellular synthesis and migration of RNA and the metabolism of protein were studied by autoradiography following an injection of³H-cytidine or³H-l-phenylalanine and double injections of 1 of these precursors +³H-thymidine. The following results were obtained: the synthesis and migration of RNA and the metabolism of protein are enhanced under these conditions of proliferation. In spite of this, the relation of metabolic activity in nucleolus, karyoplasm and cytoplasm remains constant. By double injection techniques it is proved that no differences exist in migration of RNA into the cytoplasm and cytoplasmic protein synthesis between cells with or without DNA synthesizing nuclei.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Artbastarde in der GattungTilapia (Cichlidae,Teleostei) und ihr Verhalten

Summary The young ofTilapia mossambica (mouth-brooder) show a characteristic contact-behaviour, which is related to the behaviour of the mother fish, who takes them back into the mouth cavity in cases of disturbance. This contacting is lacking in the young ofTilapia tholloni (substrate spawner). Contacting, as studied in our experiments with models, is genetically determined and is dominant over thetholloni pattern in the crossT. mossambica ×T. tholloni .     

Aktivität der Aldolase und der Succinatdehydrogenase (SDH) in der weissen und roten Skelettmuskulatur junger und alter Ratten

Summary The activity of aldolase and succinatdehydrogenase (SDH) in white and red skeletal muscle of young (3–7 months) and old (20–30 months) rats has been determined. In addition also the SDH of liver was measured. The activity of aldolase is higher in white than in red muscles, while SDH shows a higher activity in red than in white muscles. The activity of aldolase is not influenced by ageing in white muscles, but decreased in red muscles by 23%. In old animals the activity of SDH is 34% less in white and 52% less in red muscles. In liver the activity is 44% less. The significance of these changes for the energy metabolism of skeletal muscle is discussed.     

Raster-elektronenmikroskopische Untersuchungen an der Hausstaub- und Asthma-MilbeDermatophagoides pteronyssinus (Trouessart, 1897) (Acarina: Astigmata)

Summary Various methods of fixation ofDermatophagoides pteronyssinus for the REM were tested. OsO₄ vapor yielded the best results. The morphology of male and female mites is described, based on REM exposures.

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Naturhistorisches Museum Basel.     

Das Auftreten von Koproporphyrin in Kulturen vonPoteriochromonas stipitata nach Inkubation mit 3-Amino-l,2,4-triazol (Amitrol)

Summary In the presence of more than 2×10^–3 M amitrole, a red pigment was synthesized in the unicellular algaPoteriochromonas stipitata. By means of TLC it was confirmed that it consists mainly of coproporphyrine.     

Die Veränderungen der Succinodehydrase-Aktivität in Detroit-6 (VA) Zellen,infolge der Infektion mit demHepatitis-infectiosa-Virus

Summary The inhibitory action ofHepatitis infectiosa virus on the SDH activity of Detroit-6 (VA) cell lines was investigated. The full inhibition of the SDH activity took place at the end of the third day after the infection. As this phenomenon precedes the cytopathogenetic effect of viral infection, it may be of some help in the early detection of the infection.     

Form und Zellzahl der akustischen Nervenzentren in der Medulla oblongata von Eulen (Striges)

Summary The special form and the number of nerve cells of the auditory centres in the owl's medulla are described and compared with those of other birds. The highest degree of differentiation is found in the most nocturnal species,Tyto alba. Comparing the number of auditory nerve cells in the medulla with the weight of the brain in birds of different size, an unexpectedly low rate of increase was found.     

Kolbenzellen in der Epidermis der Galaxiidae,Galaxias attenuatus (Salmoniformes)

Summary The epidermis ofGalaxias attenuatus (Galaxiidae, Salmoniformes) was found to contain club cells that are like the alarm substance cells of the Gonorhynchiformes and Cypriniformes. Whether they are alarm substance cells, can be decided only by experiments on the fright reaction. The existence of club cells in the Galaxiidae confirms the opinion that both the Gonorhynchiformes and the Ostariophysi derived from salmonoid-like fish.     

Veränderungen der aggressiven Handlungsbereitschaft männlicher Schwertträger,Xiphophorus helleri,nach sozialer Isolation (Fische,Poeciliidae)

Summary IfXiphophorus helleri males are kept in social isolation for 14–56 days, the fights for rank order position showed an increasing duration and intensity. These results support the idea of a spontaneous accumulation of attack readiness and are in contrast to the results in cichlid fishes. It is supposed that the different influence of social isolation to aggressive behaviour corresponds to different types of social organisation anp ecological adaptations.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

The effect of locality,breed and previous tick experience on seasonal changes in the resistance of cattle toBoophilus microplus (Ixodoidea: Ixodidae)

Summary A seasonal cycle in the expression of resistance to the tickBoophilus microplus occurs in cattle in central and southeastern Queensland, Australia. This is due to a seasonal fluctuation in the capacity of cattle to mount an effective immune response against the parasitic tick and is manifest as a waning of the expression of resistance in autumn and early winter which occurs irrespective of breed or the nutritional state of the cattle.     

Einbau von H3-thymidin in zellen und gewebe vonHelix pomatia L. (gastropoda,pulmonata)

Summary It has been demonstrated by injections of H³-Thymidine into adult and juvenile snails (Helix pomatia) that the mitotic activity in the central nervous system, the connective tissue and epidermis was generally higher in juvenile animals than in adult ones. Data are given for the amount of triated thymidine labelled nuclei in the tissues, which are investigated.     

Visual spatial memory in desert ants,Cataglyphis bicolor (Hymenoptera: Formicidae)

Summary For navigation, desert ants apply piloting and dead-reckoning strategies based on terrestrial and celestial visual cues, respectively. Visual spatial memories, rather than general concepts derived from landmark constellations, are most probably used to define points on earth by nearby landmarks. The visual field of a specialized dorsal part of the ant's retina is mapped on to the celestial sphere to consider the possibility that similar mechanisms are used to define directions on earth by exploiting skylight patterns present at infinity.Supported by the Hescheler Foundation (Zurich) and the Swiss National Science Foundation grants Nos 3.529-0.75 and 3.313-0.78.     

The acceptance response ofEphestia cautella (Walker) (lepidoptera: Phycitidae) females,obtained in the absence of courting males

Summary Ephestia cautella females will respond to a jet of air with an acceptance posture, and will respond more frequently when the air carries volatiles, probably male sex pheromones, from the male wings.     

Ontogenetic fate of the neurosecretory cells in the larval brain ofSarcophaga ruficornis (fabricius, 1794) (diptera: Cyclorrhapha)

Résumé Il y a quatre groupes, 1, 2, 3 et 4, de cellules neurosécrétrices dans chaque demi-sphère du cerveau larvaire duSarcophaga ruficornis. Pendant la métamorphose, les groupes 1 et 2 deviennent antérieurs dorsaux et forment des cellules neurosécrétrices médiales de la mouche adulte; le groupe 3 devient ventral mais s'évanouit après l'éclosion de la mouche; le groupe 4 s'évanouit aussi, mais plus tôt.     

Y chromosome in the sibling speciesAnopheles atroparvus (van Thiel, 1927) andA. labranchiae (Falleroni, 1926) (Diptera: Culicidae): Differential behaviour of the short arm after acid-alkaline treatment and Coriphosphine-O staining

Summary An acid-alkaline treatment followed by Coriphosphine-O staining was used for detecting chromosomal differences between the 2 sibling speciesAnopheles atroparvus (van Thiel) andA. labranchiae (Falleroni) (Diptera: Culicidae). The short arm of the Y chromosome was found to stain differently in the 2 species.The authors wish to thank the entomologist C. Contini for collecting and classifyingA. labranchiae larvae and Prof. U. Bianchi and Prof. U. Laudani for helpful discussions and suggestions on the subject.     

Ecdysteroid titre and caste determination in the ant,Pheidole pallidula (Nyl.) (Hymenoptera: Formicidae)

Summary In the antPheidole pallidula, ecdysteroid level is higher in worker-biased eggs than queen-biased eggs. Moreover queens laying worker-biased eggs exhibit a higher ecdysteroid level than queens laying queen-biased eggs.