Difference in electrical activity during wakefulness and the phase of ‘sleep with muscular twitches’ as recorded from the cortex of the marsupialDidelphis azarae (South American opossum)

Resumen Se ha observado una neta diferencia entre los registros electroencefalográficos de la vigilia y la fase de « Sueño con sacudidas musculares » del MarsupialDidelphis azarae según sea la posición de los electrodos sobre la corteza cerebral.     

Rocket UV flash spectra from the solar eclipse of March 7, 1970

Flash spectra of the total solar eclipse throughout all its phases have been obtained in the extreme ultraviolet for the first time.     

Demonstration of a net movement of water through the lens

Résumé Des cristallins de lapins couvés dans des diméthylsilicones sécrètent un fluide à leur surface antérieure. Ce fluide peut prendre le même aspect et la même réticulation qu'un morceau du tissu de la surface postérieure, si le cristallin est excisé promptement après la mort.

---

---

This work was supported in part by a grant from the Institute of Neurological Diseases and Blindness N.I.H., No. NBO1979. The technical assistance ofR. Lukanen and CarolynMcDonald with picture taking and lens preparation respectively is gratefully acknowledged. The author gives a special thanks to Prof.J. E. Harris for helpful discussions and encouragement wihch led to this work.     

Amplification of immunoglobulin lambda constant genes in populations of wild mice

The lambda immunoglobulin light chain (Ig lambda) locus of BALB/c inbred mice consists of two variable region gene segments (V lambda)1-3, and four constant region gene segments (C lambda)1,2,4,5. Each C lambda gene segment is associated with a unique joining segment (J lambda)2,4-7, and they are organized in two paired units, J3C3-J1C1 and J2C2-J4C4 (refs 4, 8). Using cDNA probes specific for C lambda 1 and C lambda 2 (ref. 9) we have analysed the genomic organization of the C lambda gene segments in wild-derived and inbred strains of mice. Although Southern blots of the genomic DNA of inbred mice show a constant pattern of hybridization, wild-derived mice show a high degree of variation in the number, size and intensity of hybridizing fragments. We have now found that, per haploid genome, mice of a Mus musculus musculus stock isolated from Sladeckovce, Czechoslovakia (CzII) have at least 12 C lambda segments, and mice of a Mus musculus domesticus stock 'Centreville Lights' from Centreville, Maryland (CL) have at least 8 C lambda segments. There appears to have been relatively recent amplifications of the C lambda gene segments in wild mice.