Appearance of growth-inhibiting activity (G1 chalone) during ontogenetic development of rat and chick epidermis in vivo and in vitro

Summary A comparative study was carried out between the stage of embryonic development of epidermis and its content of growth-inhibitory activity (G₁ chalone). Injections of aqueous extracts from keratinized fetal rat or chick embryo epidermis led to a depression of DNA-synthesis in adult mouse epidermis, whereas extracts from undifferentiated epidermis did not contain such an activity.This investigation was supported by the Deutsche Forschungsgemeinschaft.     

Role of Drosophila alkaline ceramidase (Dacer) in Drosophila development and longevity

Ceramidases catalyze the hydrolysis of ceramides to generate sphingosine (SPH) and fatty acids, and ceramide metabolism is implicated in various biological responses in Drosophila melanogaster. Here we report the cloning, biochemical characterization, and functional analysis of a Drosophila alkaline ceramidase (Dacer). Dacer, a membrane-bound protein of 284 amino acids, shares homology with yeast and mammalian alkaline ceramidases. Overexpression of Dacer in High Five insect cells increases ceramidase activity in the alkaline pH range, indicating that Dacer is a bona fide alkaline ceramidase. Dacer mRNA is highly expressed in the midgut and at the pupal stage. An inactivation of Dacer by insertional mutagenesis increases the levels of ceramides in both Drosophila pupae and adult flies. Dacer inactivation increases Drosophila pre-adult development time, lifespan, and anti-oxidative stress capacity. Collectively, these results suggest that Dacer plays an important role in the Drosophila development and longevity by controlling the metabolism of ceramides.     

Appearance of growth-inhibiting activity (G1 chalone) during ontogenetic development of rat and chick epidermis in vivo and in vitro.

A comparative study was carried out between the stage of embryonic development of epidermis and its content of growth-inhibitory activity (G1 chalone). Injections of aqueous extracts from keratinized fetal rat or chick embryo epidermis led to a depression of DNA-synthesis in adult mouse epidermis, whereas extracts from undifferentiated epidermis did not contain such an activity.     

Role of bacterial endotoxins in intestinal ischemic (SMA) shock

Zusammenfassung Es werden Versuche zur Aufklärung der Rolle der gram-negativen Bakterien im irreversiblen ischämischen Darmschock durchgeführt: Ratten erweisen sich unter dem Einfluss einer milden Form von ischämischem Darmschock keinesfalls für Endotoxemia empfindlicher als falsch operierte oder normale Tiere, die dieselben Dosen von bakteriellem Endotoxin erhalten haben. Dadurch wird die Rolle der Endotoxemia in der Pathogenese des irreversiblen Darmschocks fragwürdig.     

The effect of phenylthiocarbamide (PTC) on mouse brain development

Summary PTC-when dispensed during the whole fetal development-causes a disturbance of brain development in new born mice. This disturbance is manifested by a reduction of the cell number, a reduced protein content and a reduced activity of acetylcholinesterase in the brain.     

Effects of tricaine methane sulphonate (M.S. 222) on the blood glucose levels in adult salamanders (Diemicytlus viridescens)

Summary Exposure to M. S. 222 results in hyperglycemia in adult newts (Diemicytlus viridescens). A combination of higher anesthetic concentrations with reduced exposure periods reduces the magnitude of this form of stress response.This work was supported by National Research Council of Canada Grant No. A9753 to S. Vethamany-Globus and No. A6933 to M. Globus.     

Influence of an injection of chorionic hormone (HCG) on the accumulation of testicular fluid following ligature of the vas deferens in adult Wistar rats]

Using the weight gain of the testis after efferent duct ligation, we have measured the testis fluid secretion. A single injection of HCG to Rats before, at the time or after the ligation leads to three types of effects: no effect which can be explained by the metabolisation of the hormone: a positive and/or a negative one. If the stimulating action of HCG remains unexplained, it must be related with ether anaesthesia. It seems likely that the decrease of testicular fluid secretion may represent the fundamental action of HCG upon the exocrine function of the testis, but the mecanism by which this action occurs remains to be solved.     

Effect of the insecticide Sumithion (Fenitrothion) on embryonic development in a frog

Cellular and Molecular Life Sciences - The toxic effects of Sumithion on developing embryos of a frog,Microhyla ornata, were investigated for a period of 96h. Abnormalities observed were loss of...     

Morphological evidence for axonal transport of glycogen in neurons innervating cutaneous receptors inLacerta sicula (Squamata: Reptilia)

Summary Three types of glycogen-containing cutaneous nerve terminals — two of them hitherto unknown — are described. It is shown that the glycogen is synthesized in the perikaryon and transferred to the terminals by means of slow axoplasmic transport.