Autoradiographic studies of yolk nucleus in fish oocytes

Résumé L'expulsion de la matière nucléolaire dans les ufs du poisson est étudiée ici par autoradiographie. Employant la cytidine-H₃, nous avons vu que le RNA nucléolaire passe dans le cytoplasme sous forme diffuse, et non comme un nucléole complet appelé « noyau-jaune ».

---

---

I wish to thank Dr.D. J. Fluke and Dr.H. S. Roberts for the supply of autoradiographic material.     

Endogenous synthesis of lipid yolk in mosquito oocytes

Summary Morphological and physiological evidence indicate that lipid yolk in the mosquito is synthesized only within the oocyte within dense fields of free ribosomes. It does not come from the fat body or any other exogenous source.We are grateful to Dr A. L. Steinhauer for his support. Scientific article No. A2373, contribution No. 5388 of the Maryland Agricultural Experiment Station.     

Distribution ofγ-aminobutyric acid (GABA) in the ganglia ofAplysia kurodai

Summary The concentration of GABA was determined in each ganglion ofAplysia kurodai by microassay. Highest concentration was observed in buccal ganglia.The authors are indebted to Miss C. Shimada for her skillful assistance and are also grateful to Dr. H. Koike in our institute for his advice to handleAplysia, to Dr. S. Ameniya, Misaki Marine Biology Station, University of Tokyo, for his support to get the animals.     

Esterase polymorphisms in European and American populations of the periwinckle,Littorina littorea (Gastropoda)

Résumé La structure génétique de 7 populations du gastéropode marinLittorina littorea a été étudiée par analyse de phénotypes d'estérases révélés par électrophorèse sur gel de polyacrylamide. Les populations des USA (Maine, Massachusetts), d'origine récente, ont davantage de variation géographique que celles de France, d'origine ancienne. De plus, parmi ces dernières il y a réduction de l'hétérozygotie dans l'échantillon semi-isolé du Golfe du Morbihan.     

Organization of the multifunctional neural network regulating visceral organs inHelix pomatia L (Mollusca,Gastropoda)

Summary InHelix pomatia L. the overlapping neuronal network was found to regulate the visceral functions (e.g. cardiorenal, respiratory and genital functions). The neural network is organized around the multifunctional interneurons, which take part in forming both afferent and efferent pathways. The interneurons are sensitive to a wide range of neurotransmitters or transmitter candidates including low molecular weight substances (ACh, 5HT, DA, octopamine, glutamate) and several oligopeptides. In this system both selection of information and modification of membrane properties (for example habituation) are carried out by a combination of simultaneously liberated active agents.     

Selected decrease of haemocytes of the freshwater snailPlanorbarius corneus (L.) (Gastropoda,Pulmonata) after bacteria injection

Summary The decrease of haemolymph phagocytic cells (SH) inPlanorbarius corneus after bacterial injection seems to be mediated by humoral factor(s) released into the haemolymph. SH show different adhesiveness in vitro in the presence of bacterial metabolic products.     

The identification of ecdysterone (20-hydroxyecdysone) in 3 species of molluscs (Gastropoda: Pulmonata)

Summary Ecdysterone has been identified in the schistosomiasis vectorBiomphalaria glabrata Say and inHelix aspersa Müller as well as inLymmaea stagnalis L. by chromatography, bioassay, radioimmunoassay, derivatization and by mass spectroscopy. Analysis of the food, faeces and hepatopancreas suggest that the sterol is derived from the diet. The probable function of ecdysterone in relation to calcification of the shell is discussed in this paper.We wish to thank Professor P. Karlson and Dr J. Koolman (Phillips University, Marburg-Lahn, FRG) for providing facilities for RIA. The initial study was begun at the University of Sussex and continued at the Courtauld Institute of Biochemistry, Middlesex Hospital Medical School, London, while D.L.W. was supported by the Ministry of Overseas Development. London and the Medical Research Council of Great Britain (grant G974/525/T). We thank Mr P. Mellon for the mass spectrum and Dr G.B. Russell for his interest in the earlier part of this study. We also thank Professor E. Scherer and Dr Q. Uwe (University of Essen, FRG) for their help in the irradiation ofL. stagnalis.Gauss Str. 82, D-4630 Bochum 5 (Federal Republic of Germany). Research results usingL. stagnalis were submitted for the Philips Europa Wettbewerb für junge Forscher und Erfinder (1979) in a thesis entitled Zur Frage der Existenz von Steroiden und Gonadoliberin bei der Grossen Schlammschnecke (Lymmaea stagnalis L.): ein Beitrag zur Evolution der Insekten- und Wirbeltierhormone.     

Selected decrease of haemocytes of the freshwater snail Planorbarius corneus (L.) (Gastropoda, Pulmonata) after bacteria injection

The decrease of haemolymph phagocytic cells (SH) in Planorbarius corneus after bacterial injection seems to be mediated by humoral factor(s) released into the haemolymph. SH show different adhesiveness in vitro in the presence of bacterial metabolic products.     

Polarity and symmetry in composite oocytes ofCarausius morosus Br. (Cheleutoptera,Phasmidae)

Zusammenfassung Der Follikelbau mit mehreren Oocyten in den panoistischen Ovariolen vonCarausius morosus wird beschrieben. Die Follikelentwicklung ist polar oder apolar und die Oocytenkerne konzentrieren sich bei rotations- oder bilateralsymmetrischem Oocytenkomplex.     

A specific protein in the genusRhynchosciara (Diptera,Sciaridae)

Summary Proteins immunologically related toRhynchosciara americana larval protein 10 occur in the hemolymph and ovaries of five different fly species of the genusRhynchosciara. Electrophoretic analyses showed these proteins to have a mol.wt similar to that of theR. americana protein 10 (43,000), e.g. theR. hollanderi protein 44,300, theR. milleri protein 45,500.