Loss of alleles at loci on human chromosome 11 during genesis of Wilms' tumour

Evidence that recessive cellular alleles at specific chromosomal loci are involved in tumorigenesis has been recently shown by work on tissues from patients with retinoblastoma, a neoplasm of embryonic retina whose predisposition is inherited as an autosomal dominant trait. A comparison of germ-line and tumour genotypes at loci on human chromosome 13, defined by restriction fragment length polymorphisms, showed that loss of the chromosome bearing the wild-type allele at the Rb-1 locus occurred frequently in the development of retinoblastoma. We report here results of similar studies of another embryonal neoplasm, Wilms' tumour of the kidney. Examination of germ-line and tumour genotypes from seven patients showed that five cases were consistent with the presence on human chromosome 11 of a locus in which recessive mutational events are expressed after abnormal chromosomal segregation events during mitosis.     

A novel reaction at low temperature between nucleotides and protein enhancing biological activity

Résumé Une protéine du foie, en partie purifiée, congelée en présence de nucléotides ou de thymine a montré un accroissement d'activité. Ceci résulte en une augmentation de 50 fois la valeur nutritive, lorsque ajoutée au milieu chimique défini pour la culture du nématodeCaenorhabiditis briggsae. Un changement physique de la protéine est postulé, à cause du changement de la rotation optique de l'absorption aux UV qui accompagne l'accroissement d'activité.

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This investigation was supported in part by Research Grant E-926 made to Kaiser Foundation by the National Institute of Allergy and Infectious Diseases, Public Health Service, Bethesda (Maryland).

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The authors acknowledge the valuable technical assistance of Mrs.Gladys Perez-Mendez and Mrs.Barbara Washauer Clarke.     

Extreme climate of the global troposphere and stratosphere in 1940-42 related to El Niño

Although the El Ni?o/Southern Oscillation phenomenon is the most prominent mode of climate variability and affects weather and climate in large parts of the world, its effects on Europe and the high-latitude stratosphere are controversial. Using historical observations and reconstruction techniques, we analyse the anomalous state of the troposphere and stratosphere in the Northern Hemisphere from 1940 to 1942 that occurred during a strong and long-lasting El Ni?o event. Exceptionally low surface temperatures in Europe and the north Pacific Ocean coincided with high temperatures in Alaska. In the lower stratosphere, our reconstructions show high temperatures over northern Eurasia and the north Pacific Ocean, and a weak polar vortex. In addition, there is observational evidence for frequent stratospheric warmings and high column ozone at Arctic and mid-latitude sites. We compare our historical data for the period 1940-42 with more recent data and a 650-year climate model simulation. We conclude that the observed anomalies constitute a recurring extreme state of the global troposphere-stratosphere system in northern winter that is related to strong El Ni?o events.     

An interplanetary shock traced by planetary auroral storms from the Sun to Saturn

A relationship between solar activity and aurorae on Earth was postulated long before space probes directly detected plasma propagating outwards from the Sun. Violent solar eruption events trigger interplanetary shocks that compress Earth's magnetosphere, leading to increased energetic particle precipitation into the ionosphere and subsequent auroral storms. Monitoring shocks is now part of the 'Space Weather' forecast programme aimed at predicting solar-activity-related environmental hazards. The outer planets also experience aurorae, and here we report the discovery of a strong transient polar emission on Saturn, tentatively attributed to the passage of an interplanetary shock--and ultimately to a series of solar coronal mass ejection (CME) events. We could trace the shock-triggered events from Earth, where auroral storms were recorded, to Jupiter, where the auroral activity was strongly enhanced, and to Saturn, where it activated the unusual polar source. This establishes that shocks retain their properties and their ability to trigger planetary auroral activity throughout the Solar System. Our results also reveal differences in the planetary auroral responses on the passing shock, especially in their latitudinal and local time dependences.     

Hox cluster disintegration with persistent anteroposterior order of expression in Oikopleura dioica

Tunicate embryos and larvae have small cell numbers and simple anatomical features in comparison with other chordates, including vertebrates. Although they branch near the base of chordate phylogenetic trees, their degree of divergence from the common chordate ancestor remains difficult to evaluate. Here we show that the tunicate Oikopleura dioica has a complement of nine Hox genes in which all central genes are lacking but a full vertebrate-like set of posterior genes is present. In contrast to all bilaterians studied so far, Hox genes are not clustered in the Oikopleura genome. Their expression occurs mostly in the tail, with some tissue preference, and a strong partition of expression domains in the nerve cord, in the notochord and in the muscle. In each tissue of the tail, the anteroposterior order of Hox gene expression evokes spatial collinearity, with several alterations. We propose a relationship between the Hox cluster breakdown, the separation of Hox expression domains, and a transition to a determinative mode of development.