Alteration in the SAT-chromosome ofAllium cepa affecting the size of the nucleolus

Resumen Se describe el hallazgo de un bulbo deAllium cepa en el cual los dos nucleolos de cada nÚcleo muestran una clara diferencia de tamaño. El nucleolo menor posee aproximadamente la mitad del diámetro del nucleolo normal. Esta alteración de la morfología nucleolar se correlaciona con la ausencia de satélite en uno de los dos cromosomas normalmente satelizados.

---

---

The work reported in this paper was undertaken during the tenure of a Research Training Fellowship awarded by the International Agency for Research on Cancer.     

On the possible existence of muscarinic cholinoreceptors on the postsynaptic membrane of the frog muscle

Zusammenfassung An den postsynaptischen Muskelzellmembranen werden Befunde erhoben, welche darauf hinweisen, dass qualitativ keine Differenzierung zwischen muskarin- und nikotinartigen Rezeptoren möglich ist.     

Effect of ions on the light-sensitive current in retinal rods

The effect of ions on the light-sensitive current of retinal rods was studied by sucking the inner segment into a tightly fitting capillary with the outer segment projecting into a flowing solution. This new method showed that the light-sensitive pathway, in which Na+ is the normal carrier of current, has an ionic selectivity different from that of other known sodium channels. Externàl calcium has a striking effect on the current, which increased about 20-fold when all calcium was removed. Reducing the sodium concentration gradient greatly prolonged the response to a flash of light, as would be expected if internal calcium blocks sodium channels and if light releases calcium which is subsequently extruded by a sodium-calcium exchange mechanism.     

Kompensation der teratogenen Wirkung eines Thalidomid-Metaboliten durchl-Glutaminsäure

Summary Skeletal defects were observed in the off-spring of SWS-mice following i.p. administration of phthaloyl-l-glutamic acid, a metabolite of thalidomide. The fetuses of animals which receivedl-glutamic acid in addition to the teratogenic drug, did not show any malformations, whereas concurrent i.p. administration of thed-isomer of glutamic acid failed to reverse teratogenicity induced by phthaloyl-l-glutamic acid.