Control of leaf morphogenesis by microRNAs

Plants with altered microRNA metabolism have pleiotropic developmental defects, but direct evidence for microRNAs regulating specific aspects of plant morphogenesis has been lacking. In a genetic screen, we identified the JAW locus, which produces a microRNA that can guide messenger RNA cleavage of several TCP genes controlling leaf development. MicroRNA-guided cleavage of TCP4 mRNA is necessary to prevent aberrant activity of the TCP4 gene expressed from its native promoter. In addition, overexpression of wild-type and microRNA-resistant TCP variants demonstrates that mRNA cleavage is largely sufficient to restrict TCP function to its normal domain of activity. TCP genes with microRNA target sequences are found in a wide range of species, indicating that microRNA-mediated control of leaf morphogenesis is conserved in plants with very different leaf forms.     

Contribution to the co-rotating magnetic field model of the pulsar

A new general solution of the electromagnetic field equations convenient for rotating field problems is used to analyse the case of low plasma number density. Two localized pulse emitting regions rotating with the star at approximately twice the velocity of light radius are predicted.     

Infusion of a novel peptide, PHI, in man. Pharmacokinetics and effect on gastric secretion

PHI, infused in man, achieved plateau plasma levels of 297 pmoles/1. The plasma half life was 3.1 min, metabolic clearance rate was 16.4 ml/kg/min and estimated volume of distribution was 73.2 ml/kg. No subjective side effects were noted during the infusion and there was no significant alteration in submaximal pentagastrin stimulated gastric acid or pepsin secretion.     

A source of cutaneous maternal semiochemicals in the mink?

Summary Unique hypertrophic apocrine sweat glands are described in the neck, perineal and inguinal skin of mink kits. These glands enlarge after birth, only to regress rapidly and become vestigal by weaning. No similar phenomenon has been recognized before in mammals. Behavioral studies indicate a possible role for the glandular secretion in maternal recognition of the young.     

Changes induced by the acute administration of iodide on secretion of iodinated components by the rat thyroid gland perfused in situ

Résumé Nous avons étudié l'effet de l'iodure 127 (10^–3 et 10^–4 M) sur la sécrétion de T₄ ^*, T₃ ^* et –I^* par la thyroïde de rat, prémarquée à l'iode 131 et perfusée in situ avec du sang non radioactif contenant 12 mU de TSH/ml. Il n'a pas été noté de changement significatif dans la sécrétion de T₄ ^* ou T₃ ^* jusqu'à 45 min après le début de l'administration d'iodure 127, qu'il y ait ou non du méthimazole (10^–3 M) dans le sang perfusé. Il y avait par contre une augmentation de la sécrétion d'-I^* pendant la perfusion de 10^–3 M d'ïodure, indiquant une décharge d'-I^* pendant la perfusion de 10^–3 M d'ïodure, indiquant une décharge d'-I^* de provenance intrathyroïdienne. Cet effet est similaire à celui noté auparavant pendant le perfusion de 10^–3 M de ClO ₄ ^– .