The binding of cardiac glycosides to bull spermatozoa

Resumen Se ha investigado la unión de glicósidos cardiacos al espermatozoide de toro. Dicha unión es sensible a inhibidores metabólicos y fué localizada en la membrana celular del segmento intermediario y la cola.     

Germ cell population of chick embryos incubated 5 1/2 days after ultraviolet irradiation of young blastoderms]

Chick blastoderms, incubated for 5 hrs., were wholly irradiated with ultraviolet light (2 537 A). With ultraviolet doses of 14,400 and 16,200 erg/mm2, the embryos, ofter morphologically abnormal, which developed from these blastoderms, were shown to contain, at 5 1/2 days of incubation, very few or no germ cells in the region of their primordia.     

The effect of N′-Nitro-N-Nitroso-N-Methylguanidine on the liver after administration to the rat

Résumé La nitrosoguanidine administrée à des rats par sonde stomacale provoque la formation de très nombreux kystes biliaires dans le foie et, dans chaque cas, de tumeurs d'estomac squameuses.     

Acid phosphatase activity of small intestine of mice after exposure to different doses of gamma rays

Summary Effect of whole-body radiation at 3 different dose levels on the activity of acid phosphatase was studied in the small intestine of Swiss albino mice. In all the 3 exposure groups the enzyme activity increased significantly at 24 h after irradiation; the time at which the maximum histological damage was seen. With the beginning of recovery the enzyme tended to decrease and gradually approached control values.     

Nitrogenase activity in a transfilter culture of rhizobia with a non-leguminous plant callus culture: Transfer of fixed15N2 from bacteria toPortulaca callus

Summary A transfilter culture of the non-leguminous plantPortulaca grandiflora var. JR andRhizobium sp. cowpea 32H1 was established. Using¹⁵N₂-analysis we demonstrated that¹⁵N-containing substances produced by the bacteria passed through the membrane and¹⁵N was enriched in the plant cells.Acknowledgment. The authors wish to express their gratitude to Prof. H. Marschner and Dr G. Hentschel for the determination of the nitrogen-content of our samples by the Dumasmethod and for advice on the optic emission method. Drs J. Burton, Milwaukee, Wisc., and Tjepkema, Oregon State University, are thanked for generous gifts ofRhizobium sp. cowpea 32H1. This work was supported by the DFG.     

Cerebrospinal fluid pH,pCO2 and bicarbonate of the conscious dog,under exposure to high ambient temperature

Zusammenfassung An 13 wachen Hunden wurde bei normaler und bei erhöhter Umgebungstemperatur der Kohlensäurepartialdruck, die Wasserstoffionenkonzentration und der Bikarbonatgehalt des arteriellen Blutes und des Liquor cerebrospinalis gemessen. Danach ergab sich, dass diese Werte sowohl im arteriellen Blut als auch im Liquor cerebrospinalis während der Wärmepolypnoe änderungen im Sinne einer respiratorischen Alkalose aufzeigen.     

Increase in the non-specific resistance to infection in mice after oral administration of 2 synthetic glycopeptides with adjuvant activity]

Two synthetic glycopeptides (MurNAc-L-Ala-D-isoGln and MurNAc-L-Ala-D-Glu), having adjuvant activity, were shown to enhance non-specific resistance to infection against K. pneumoniae. These compounds were active by various routes including oral administration and even if administered after the challenge. Two steroisomers lacking adjuvant activity did not protect the infected Mice.