Studies onxHaynaldoticum sardoum Meletti et Onnis metabolism during seed life-span: α-amylase and glutamate decarboxylase activity

Summary Embryo GAD activity and -amylase in the endosperm of 2 different physiological lines (CP; CV) ofxHaynaldoticum sardoum Meletti et Onnis were evaluated and different stages of seed ripening and progressively older seeds were examined. Results concerning GAD activity during ripening show differences between CP and CV seeds, the former being more active. In the ageing seeds, the GAD remains constant (CP is twice as much as CV) up to 4th year and greatly decreases at the 5th. The -amylase activity is fairly constant during ripening in CV endosperm and increases in CP: at the fully-ripe stage, both show similar values. During seed ageing, the activity decreases progressively in CV endosperm while, in CP, values are greater but fairly constant. The results are discussed in connection with dormancy and the different physiological ageing of seeds.This work was supported by a grant from the Consiglio Nazionale delle Ricerche (Rome, Italy).Acknowledgments. The authors wish to thank Mr F. Saviozzi, Mr V. Sbrana and Mr R. Bertini for their expert technical assistance.     

Reduced carbonic anhydrase and Na−K-ATPase activity in gills of salmonids exposed to aluminium-containing acid water

Summary Exposure of young specimens ofS. salar andS. gairdneri to aluminium concentrations of 200 g/l in water at pH 5 induced reductions of 25–40% in the activity of carbonic anhydrase and Na–K-ATPase in the gills.Fish were generously supplied by Settefiskanlegget A/S, Lundamo and the Research Station for Salmonids, Sunndalsøra.     

Experiments concerning the incorporation of labelled adenine into ribonucleic acid in normal sea urchin embryos and in the hybridParacentrotus ♀ xArbacia ♂

Zusammenfassung Inkubation der Seeigelkeime mit¹⁴C-Adenin ergab, dass bei reinen Arten der Einbau der markierten Substanz in die RNS von der Mesenchymblastula bis zum Pluteus eindeutig zunimmt. Parallel zur DNS-Synthese verläuft die Zunahme beiParacentrotus undSphaerechinus viel rascher als beiArbacia. Beim Bastard PA nimmt dieser Einbauprozess mit Beginn der morphogenetischen Hemmung (nach ca. 26 h) rasch ab.     

‘Binding’ of glycine andγ-aminobutyric acid to synaptosomal fractions of 6 regions of the feline brain; effects of strychnine

Summary GABA (6×10^–6 M) binding to synaptosome-enriched fractions of cat CNS exhibited a clear rostro-caudal gradient, whereas glycine (6×10^–6 M) binding was greatest to particles of cerebellar cortex, and this was followed by medulla caudate nucleus cerebral cortex pons > corona radiata. Strychnine-SO₄ (10^–3 or 10^–4 M) inhibited the binding of GABA and glycine in all brain regions studied; at 10^–5 M this drug inhibited the binding of both GABA and glycine only to particles of the cerebral cortex.This study was supported by Centro Nacional Ramón y Cajal and Fundación Juan March. P. M. was a summer student from Eastern Nazarene College, Wollaston, Mass., USA.