Ecdysone 20-hydroxylase from the midgut of the tobacco hornworm (Manduca sexta L.)

Summary An ecdysone 20-hydroxylase enzyme system that converts -ecdysone to 20-hydroxyecdysone was prepared from the midgut of the tobacco hornworm prepupa. This partially purified enzyme is NADPH dependent and is localized in the mitochondrial fraction of the midgut tissue.     

Hormonal manipulation of carrageenin-induced pyresis in rats

Summary The intensity of the hyperthermic response in rats promoted by subplantar injection of 1 mg of carrageenin is directly related to the irritant properties of the type of carrageenin. The overall pyretic response is more dramatic in female rats than in male rats. Subtle changes in the time-course hyperthermic profiles are seen after hormonal modifications.This work was supported by NIH, MBS research grant No. RR08111.     

Permeability of fresh and stored human erythrocytes to glycerol and its acylated derivatives

Summary The effect of copper ions on the permeation of glycerol and its mono-, di-, and triacetate derivatives was studied in fresh and stored erythrocytes. Permeability was unchanged with storage. Acylated glycerols permeate the cells mainly by non-facilitated mechanism, as their transport is almost unaffected by copper ions.Portions of this work were included in the graduate thesis of Dr. Yaeger in partial fulfillment of the requirements for the M. D. degree.Acknowledgement. We thank Mrs Dalia Mazor for expert technical assistance.     

Changes in photoelectron transport of chloroplasts isolated from dark stressed leaves of maize seedlings

Summary Transfer of light-grown maize seedlings to dark causes a loss in the contents of chlorophyll, protein and RNA of leaves, and a decline in DCPIP photoreduction by isolated chloroplasts. The loss in DCPIP-Hill reaction is attributed to the dark stress-induced damage of O₂ evolving system of thylakoid membranes.Acknowledgment. We thank Prof. M.C. Dash, School of Life Sciences, for encouragement and providing the facilities.     

Modification by levo-propranolol of tremors induced by harmine in mice

Summary It has been recently reported that the levo isomer of propranolol possesses anti-serotonin properties in animals. Since harmine-induced behavioural changes in mice are reported to be mediated through central serotonergic receptors, an attempt was made to test whether 1-propranolol would also modify harmine-induced responses by virtue of its antiserotonergic or anti-adrenergic property. The results indicated that 1- and dl-propranolol inhibited central serotonin receptor mediated responses to harmine in mice, a finding that is analogous to other recent observations.     

Pattern of cell damage due to ionizing radiation in the epithelial lining of the intestine inHeteropneustes fossilis bloch

Zusammenfassung Der Vorgang der Strahlenschädigung wurde an der Epithelzellschicht des Darmes des SüsswasserfischesHeteropneustes fossilis untersucht. Schon 2 h nach der Strahleneinwirkung ist eine Veränderung der Zellform und des Zellkerns zu erkennen. Die Zellen an den Spitzen der Fasern werden als erste in das Lumen ausgepresst. Becherzellen sind besonders strahlenanfällig und verschwinden schon nach kurzer Zeit. Die Neubildung beginnt vom 2. Tag an, und Becherzellen sind vom 4. Tag an wieder zu beobachten.     

The binding of FITC-insulin to ANAE-positive cells in rat thymus

Summary To determine if thymic macrophages have insulin receptors, alternate sections of rat thymus were stained with FITC-insulin and examined for nonspecific esterase (ANAE) activity. Cells showing a diffuse ANAE staining pattern also bound FITC-insulin. These cells were concentrated in the cortico-medullary border and increased in number following administration of cortisol. Thymic macrophages may be insulin-dependent and therefore could be malfunctional in diabetes.     

Presence-absence cycles of the mother and not light-darkness are the zeitgeber for the circadian rhythm of newborn mice

The relative roles of conflicting zeitgebers [presence/absence (PA) cycles versus light/dark (LD) cycles] on entrainment of circadian rhythm of locomotor activity were tested in pups of the night active mouse Mus booduga. During the early days of the pups' life the PA cycles of the mother acted as a zeitgeber and entrained their activity rhythm, even though the LD cycles were available. Entrainment by LD cycles took place only when the pups' eyes opened and probably became functional.