Excess bioavailability of zinc may cause obesity in humans

The body weight or body weight/height ratio exhibits a positive linear correlation to hair zinc (Zn) concentration which is more strongly positive in men than in women. The obese of both sexes possess higher Zn concentrations in their hair than those with normal body weight/height. The degree of obesity increases with the increase in the hair Zn concentration.     

Homeostatic regulation of NCAM polysialylation is critical for correct synaptic targeting

During development, axonal projections have a remarkable ability to innervate correct dendritic subcompartments of their target neurons and to form regular neuronal circuits. Altered axonal targeting with formation of synapses on inappropriate neurons may result in neurodevelopmental sequelae, leading to psychiatric disorders. Here we show that altering the expression level of the polysialic acid moiety, which is a developmentally regulated, posttranslational modification of the neural cell adhesion molecule NCAM, critically affects correct circuit formation. Using a chemically modified sialic acid precursor (N-propyl-D: -mannosamine), we inhibited the polysialyltransferase ST8SiaII, the principal enzyme involved in polysialylation during development, at selected developmental time-points. This treatment altered NCAM polysialylation while NCAM expression was not affected. Altered polysialylation resulted in an aberrant mossy fiber projection that formed glutamatergic terminals on pyramidal neurons of the CA1 region in organotypic slice cultures and in vivo. Electrophysiological recordings revealed that the ectopic terminals on CA1 pyramids were functional and displayed characteristics of mossy fiber synapses. Moreover, ultrastructural examination indicated a "mossy fiber synapse"-like morphology. We thus conclude that homeostatic regulation of the amount of synthesized polysialic acid at specific developmental stages is essential for correct synaptic targeting and circuit formation during hippocampal development.     

Hairiness in wool in relation to blood potassium types in Marwari sheep

Zusammenfassung Schafe mit geringem Kaliumgehalt im Blut haben an mehreren Körperstellen weniger markhaltige Haare als Tiere mit höherem K-Gehalt.     

Effect of some insecticides on cellular lipids of the neurosecretory complex of the red cotton bug,Dysdercus koenigii

Summary In normal specimens of the bug,Dysdercus koenigii, the cells of the pars intercerebralis stain highly positively with Sudan black B and acid haematein, while the corpora cardiaca and allata stain lightly. After the administration of parathion, carbamate and endrin the situation is reversed. The increased level of lipids in the corpora cardiaca and allata coincides with the degree of loss of lipids from the cells of the pars intercerebralis.The authors are thankful to Professor G.P. Sharma for the encouragement and to Dr H. S. Vasisht, for providing them the laboratory facilities. Financial assistance provided to Dr Suman Taneja by C.S.I.R., New Delhi is gratefully acknowledged.