Special forms of amitotic nuclear division in striated muscle and other insect tissues

Résumé On décrit quelques aspects morphologiques de l'appareil nucléaire des fibres musculaires striées des insectes. Le nom Polykaryonéma est proposé pour désigner les noyaux filamenteux géants qui par fragmentations successives produisent des chaÎnes de noyaux indépendants, placées dans le centre des fibres musculaires adultes. Ce phénomène offre un bon exemple de division nucléaire amitotique.     

Diurnal variations in cholinesterase activities in the slug,Laevicaulis alte

Summary Cyclical variations in acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) levels in foot muscle (FM) and AChE activity in central nervous system (CNS) ofLaevicaulis, during 24-h-day, were maximal at 04.00 h and minimal at 12.00 h. But BuChE activity was 180°C out of phase with AChE in CNS. The rhythmic trend of AChE in CNS might be due to true cholinesterase activity.Acknowledgements. The Senior Fellowship (CSIR) awarded to TPK is thankfully acknowledged.     

Cross-linked arabinogalactan: A new affinity matrix for the purification ofRicinus communis lectins

Summary Arabinogalactan has been cross-linked to give a new high capacity affinity matrix for the purification ofRicinus communis lectins. It shows a capacity which is 50 times greater than that of the conventional affinity matrices.     

Cadmium-113 FT NMR-spectra of rabbit liver metallothioneins

Summary Cadmium-113 FT NMR-spectra of rabbit liver metallothionein-I and-II gave 6 and 7 NMR-signals, respectively, at between 610 and 670 ppm downfield from aqueous Cd(ClO₄)₂ solution (0.1 M).We thank Mr M. Imanari (JEOL) for the NMR-data and Dr K. Kubota (NIES) for encouragement.     

Modification of the action of pentagastrin on acid secretion by botulinum toxin

Summary I.v. botulinum toxin after 60–90 min abolished the dose-response relationship between pentagastrin and gastric acid secretion in anesthetized rats and guinea-pigs. The toxin reduced but did not abolish the acid stimulatory effect of histamine. As expected, the acid response to vagal stimulation was abolished and that to methacholine in rats was unaltered by the toxin.Acknowledgment. We are grateful to the generosity of Dr Edward J. Schantz, Food Research Institute, University of Wisconsin, for the botulinum toxin used. — This research was supported by NIH grant 1 RO1 AM 17125, The Secretion of Pepsin.     

Purification and structural characterisation of human HLA-linked B-cell antigens.

The human B cell-specific alloantigen which is closely linked genetically to HLA contains two non-covalently associated, sialogycoprotein subunits of molecular weight (MW) 29,000 (p29), and 34,000 (p34). Although p29 and p34 have different amino-terminal sequences, their tyrosine peptide maps indicate considerable similarity in other portions of their polypeptide chains. Thus the genes for their proteins may have evolved by duplication of a common ancestral gene. Another lymphocyte cell surface protein of MW 16,000 (p16) has also been characterised. Both p16 and p44 (the heavy chain of HLA-A,B antigens) have been compared with p29 and p34.     

Nicotinamide administration alters the activities of hepatic microsomal mixed function oxidases

Summary Systemic action of nicotinamide significantly alters the activities of hepatic drug metabolizing enzymes. Male rats injected with nicotinamide have reduced levels of cytochrome P450, demethylases and aniline hydroxylase. The changes appear to be sex-dependent since in the case of female rats activities of p-nitroanisole-o-demethylase and aniline hydroxylase are enhanced whereas cytochrome P450 content remains unaltered.Authors gratefully acknowledge the encouragement given by Professor A.S. Paintal during the course of this investigation. One of us (J.K.B.) is grateful to the Council of Scientific and Industrial Research, New Delhi, for the award of a research fellowship.