'Z-RNA'--a left-handed RNA double helix

In contrast to double-stranded DNA, there has so far been little evidence that double-stranded RNA can undergo major conformational transitions. We have investigated the conformation in different conditions of the double-stranded RNA molecule poly(G-C).poly(G-C), by NMR, circular dichroism and absorbance spectroscopy. We report here evidence obtained by these different spectroscopic techniques that poly(G-C).poly(G-C) undergoes a transition from the A-form to a left-handed Z-form in conditions of high ionic strength and at temperatures above 35 degrees C. This conformational transition may be of relevance to the biological situations in which double-stranded RNA occurs, such as in ribosomes and in some viruses.     

Studio comparativo degli aminoacidi presenti negli estratti e negli idrolizzati di retina e di epitelio corneale di bue

Zusammenfassung Mittels Papierchromatographie wurde das Bild der freien Aminos?uren der Netzhaut und des Cornea-Epithels des Rindes untersucht und mit den Aminos?uren des Hydrolysats des gesamten Gewebes in Beziehung gebracht. Die Ergebnisse zeigen, dass das Bild der freien Aminos?uren ein charakteristischer Zug eines bestimmten Gewebes ist, obwohl er nicht ganz genau dessen Zusammensetzung an Aminos?uren wiedergibt.      

Sullo sviluppo delle uova diPhallusia mamillata in condizioni di anaerobiosi

Summary The development ofPhallusia mamillata in anaerobic conditions has been the subject of these studies. The anomalies of the larvae are caused by the muscular system of the tail. The results are explained on the grounds of the recent views acquired concerning the precocious segregation of the cytochromoxidase, tied to the mitochondria in the cells which are to form the muscle system.     

Real-space imaging of an orbital Kondo resonance on the Cr(001) surface

The Kondo effect is usually connected with the interaction between a localized spin moment and itinerant electrons. This interaction leads to the formation of a narrow resonance at the Fermi level, which is called the Abrikosov-Suhl or Kondo resonance. Scanning tunnelling microscopy is an ideal technique for real-space investigations of complicated electronic structures and many-body phenomena, such as the formation of the Kondo resonance or d-wave pairing in high-T(c) superconductors. Theory has predicted that similar, Kondo-like many-electron resonances are possible for scattering centres with orbital instead of spin degrees of freedom--the quadruple momenta in uranium-based compounds or two-level systems in metallic glasses are examples of such 'pseudo-Kondo' scattering centres. Here we present evidence for the orbital Kondo resonance on a transition-metal surface. Investigations of an atomically clean Cr(001) surface at low temperature using scanning tunnelling microscopy reveal a very narrow resonance at 26 meV above the Fermi level, and enable us to visualize the orbital character of the corresponding state. The experimental data, together with many-body calculations, demonstrate that the observed resonance is an orbital Kondo resonance formed by two degenerate d(xz), d(yz) surface states.     

Gene expression profiling predicts clinical outcome of breast cancer

Breast cancer patients with the same stage of disease can have markedly different treatment responses and overall outcome. The strongest predictors for metastases (for example, lymph node status and histological grade) fail to classify accurately breast tumours according to their clinical behaviour. Chemotherapy or hormonal therapy reduces the risk of distant metastases by approximately one-third; however, 70-80% of patients receiving this treatment would have survived without it. None of the signatures of breast cancer gene expression reported to date allow for patient-tailored therapy strategies. Here we used DNA microarray analysis on primary breast tumours of 117 young patients, and applied supervised classification to identify a gene expression signature strongly predictive of a short interval to distant metastases ('poor prognosis' signature) in patients without tumour cells in local lymph nodes at diagnosis (lymph node negative). In addition, we established a signature that identifies tumours of BRCA1 carriers. The poor prognosis signature consists of genes regulating cell cycle, invasion, metastasis and angiogenesis. This gene expression profile will outperform all currently used clinical parameters in predicting disease outcome. Our findings provide a strategy to select patients who would benefit from adjuvant therapy.     

Facioscapulohumeral muscular dystrophy is uniquely associated with one of the two variants of the 4q subtelomere

Contractions in the polymorphic D4Z4 repeat array of subtelomere 4qter cause autosomal dominant facioscapulohumeral muscular dystrophy in humans. A polymorphic segment of 10 kb directly distal to D4Z4 exists in two allelic forms, 4qA and 4qB. Although both alleles are equally common in the general population, we now report that FSHD is associated solely with the 4qA allele.