Marine diatoms affecting the stability of oil-in-water emulsions and hydrocarbon distribution in sea water

Summary The importance of phytoplankton in stabilizing oil-in-water emulsion and affecting hydrocarbon distribution in the sea was studied by using marine diatoms. All microalgae tested increased emulsion stability and favored the presence of polycyclic aromatics in the sea water.     

Leydig cell andΔ 5-3β-hydroxysteroid dehydrogenase activity in the testis of toad (Bufo melanostictus) following cold exposuredehydrogenase activity in the testis of toad (Bufo melanostictus) following cold exposure

Summary Leydig cell nuclear area and ⁵-3-hydroxysteroid dehydrogenase activity were increased in the testis ofBufo melanostictus 2 days after a single short-term cold exposure. Both parameters returned to normal values 4 days later.     

Identification of an acyclic diterpene alcohol in the defense secretion of soldiers ofReticulitermes lucifugus

Summary The defense secretion of soldiers ofReticulitermes lucifugus has been shown to contain, predominantly, (R)-(–)-(E,E)-geranyllinalool together with germacrene A and -farnesene.This report covers part of a collaborative study with J.-L. Clément, Lab. d'Evolution, Université P. et M. Curie, Paris, to whom we are grateful for supplies of material and discussions. We also thank Dr O.T. Jones for collections ofReticulitermes lucifugus.     

Birefringence signals and tension development in single frog muscle fibres at short stimulus intervals

Summary The early large birefringence signal and mechanical activity were studied together in isolated single fibres of frog skeletal muscle with double stimulation at short stimulus intervals (2–60 msec) at room temperature and at 4–6°C. In all fibres tested, extra tension and additional birefringence signal in response to the second stimulus appeared simultaneously and suddenly upon increasing the stimulus interval. The shape of the stimulus-interval versus tension-development curve makes it highly improbable that subthreshold calcium release occurs at shorter stimulus intervals; therefore, tension development reliably reflects Ca-release in these experiments. In contrast to the report by Suarez-Kurtz and Parker, birefringence signal and calcium release are shown not to be dissociated by double stimulation. This result supports the hypothesis that the early large birefringence signal is an intrinsic indicator of calcium release from the sr during EC-coupling in skeletal muscle.     

Spierule cells inDrosophila species

Summary Spherule cells are restricted to the larval stage and make up 5–16% of cells in the hemolymph. Their morphology varies between species, mainly due to the shape of their inclusions which may be oval (spheroidocytes), polyhedral (crystalloid cells), or clearly crystalline (crystal cells). These inclusions are very rich in tyrosine. They liquefy rapidly in vitro, whereby the cells become hyaline (coagulocytes).Acknowledgments. We thank Mr B. Barandun for excellent technical assistance. This investigation was supported by the Swiss National Science Foundation, grant No. 3.792.076.     

Blocking by picrotoxin of nigra-evoked inhibition of neurons of ventromedial nucleus of the thalamus

Summary The transmitter substance released by nigro-thalamic fibres is proposed to be -aminobutyric acid, since picrotoxin blocked nigra-evoked monosynaptic inhibition of thalamic neurons.Supported by grants Nos 212009 and 311410 from Ministry of Education of Japan.The authors wish to thank Dr Marjorie Anderson, University of Washington, Seattle, for improving the English.     

Chemotherapeutic effects of 4-isothiocyanato-4′-nitrodiphenylamine (C9333-Go/CGP 4540) on infections withNematospiroides dubius,Hymenolepis diminuta,Hymenolepis nana andSpirometra mansonoides

Summary 4-Isothiocyanato-4-nitrodiphenylamine possessed anthelmintic activity againstNippostrongylus dubius andHymenolepis nana in mice andH. diminuta in rats as determined by both egg counts and recovery of parasites at autopsy. No activity was detected against the cestode,Spirometra mansonoides, in cats.This investigation was supported in part by grants AI-10512 and AI-09483 from the National Institutes of Health. The authors are indebted to Dr P.P. Weinstein for providing animals infected withSpirometra mansonoides.     

Production and detection of antibody against estradiol receptor in the calf uterus. Interaction with the estrogen receptor from the hen oviduct]

The antibodies against estrogen receptor were obtained after injecting Rabbits with a cytoplasmic receptor fraction isolated from Calf uterus. The estrogen receptor was partially proteolysed by the action of trypsin and subsequently purified by affinity chromatography (purification 4,000 to 10,000 fold, to a purity of 5-20%). The affinity of the antibody for the proteolysed receptor is KD approximately 1 nM and serum titres have reached values of approximately 50 nM. The values remained constant after the third injection. Preliminary results indicate that the antibody has approximately the same affinity for "native" cytoplasmic estrogen receptor from Calf uterus, as well as for the "trypsinized" forms of estrogen receptor isolated from Calf uterine cytosol and Hen oviduct nuclei.     

Plasma growth hormone in the rabbit fetus. Relation to maturation of the liver and lung]

Day 25 after insemination is a date of peculiar importance in the maturation of several organs in the Rabbit fetus. From day 25 onward the fetal liver stores increasing amounts of glycogen and the lung stores increasing amounts of lecithins, concomitant with sudden rise in the activity of lung phosphatidic-acid phosphohydrolase. Earlier studies on decapitated fetuses established that glycogen storage in the liver is dependent on a dual hormonal control, comprising a pituitary hormone like growth hormone or prolactin (some placental hormones share the same activity) and corticosteroids (Jost, 1961). Since the variations in endogenous corticosteroids do not seem to herald these liver or lung changes (Mulay et al., 1973), a study was made of growth hormone. Plasma immunoreactive growth hormone--determined with a heterologous Rat system (Kervran et al., 1976)--increases eightfold between days 23 and 25. During the same time plasma prolactin does not change according to McNeily and Friesen, 1978, and to unpublished data obtained with Dr McNeilly. In preliminary assays, Rat growth hormone was seen to increase phosphorylase "a" activity in the lung of 18.5 day-old Rat fetuses, thus anticipating normal development. We suggest that growth hormone plays a role in initiating liver and lung maturation.     

Stereotype and plasticity of utterances in gibbons (Hylobates concolor leucogenys)]

The "great call" of adult male and female Hylobates concolor leucogenys was studied in different conditions of social stimulation, using quantitative (i. e. sonographic) analysis. Vocal sequences are generally made up of mixed sounds, appearing in a fixed order and constituting a species-specific character. Qualitative diversification appears in the repetition of sequences. Different social situations alter parameters of the calling pattern: especially the length and intensity of homologous modulated sounds, and the qualitative complexity of sequences. The capacity of controlling length and intensity of modulated sounds has been shown in earlier papers for H. c. gabriellae, and by several authors, in Cebus and Rhesus monkeys. The "great call" of H. c. leucogenys shows the two fundamental characteristics of instinctive (i. e. genetically determined) activity-patterns.