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G Quagliarotti

Publications and source records attributed to G Quagliarotti.

9 recordsLinked to original sources
PubMed1991

Recent progress in vertebrate limb morphogenesis.

Morphogenesis of vertebrate limb, specifically that of the chick wing, has been recognized as a suitable model to study the cellular and molecular mechanisms of pattern formation. The importance of cellular inductive phenomena and the relevance of the processes such as cell division and cell death in the above model are discussed. These studies have revealed the retinoic acid (RA) and retinols as convincing candidates for vertebrate morphogens. The recent discovery that the RA receptors belong to the steroid hormone receptor superfamily might indicate the universality of the RA morphogen and might enlighten the possible mode of its action. Identification and characterization of the 1d locus genes associated with the mouse limb morphogenesis and the possible involvement of the homeobox proteins in chick wing development have opened new prospects in understanding the molecular mechanisms of vertebrate morphogenesis.

Animals↗
PubMed1986

Structuring of H1 histone. Evidence of high-affinity binding sites for phosphate ions.

Circular dichroism studies show that low concentrations of phosphate ions induce folding of the H1 histones. Sulfate and perchlorate anions have effects similar to phosphate indicating the presence on H1 histones of binding sites with high affinity for ions with tetrahedral geometry. In fact, the structuring efficiency of different ions, as determined by the midpoint value of the effect/concentration curve, is 0.05 M for NaCl, 0.005 M for NaClO4, 0.001 M for sodium phosphate and 0.0003 M for sodium sulfate on H1 histone from Chaetopterus variopedatus sperm chromatin. Phosphate shows similar folding efficiency also on calf thymus and on sea-urchin sperm H1 histones. The effect of phosphate ions on the H1 molecule is observed also by differential absorption spectroscopy in the region of absorption of amino acid side-chains. Binding studies by gel filtration chromatography on Sephadex columns show that phosphate binding occurs in the presence of structuring concentrations of sodium chloride. About 9 ATP molecules bind to H1 histones derived from non-active cell chromatins while only 3.5 ATP molecules bind to H1 derived from active somatic chromatins. The fluorescence of the tyrosine residues of Chaetopterus sperm H1 is enhanced by chloride ions and heavily quenched by phosphate ions in correlation with structuring of the molecule, demonstrating direct interactions between tyrosine residues and phosphate ions. The defined and limited number of phosphate groups bound per histone molecule, the high affinity of the interaction and the effect on the structure of the histone suggest the participation of phosphate groups in the binding of H1 histones to DNA.

Animals↗