Dial variations in the levels of blood glucose and hepatopancreatic glycogen in the slug,Laevicaulis alte (Ferussac 1821)

Summary InLaevicaulis alte maximal blood glucose level at 00.00 h alternates with minimal level at 12.00 h of the day, while hepatopancreatic glycogen showed an opposite trend. Variations in blood glucose levels are inversely proportional to the corresponding variations in hepatopancreatic glycogen content, while blood glucose level shoots up to a maximum, hepatopancreatic glycogen declines to a minimum and vice versa.Acknowledgment. The authors thank Prof. K.S. Swami for providing facilities. The financial assistance rendered by ICMR (DCR), UGC (VJ) and CSIR (KS), New Delhi, India is gratefully acknowledged.     

Post-transcriptional gene silencing of ribosomal protein S6 kinase 1 restores insulin action in leucine-treated skeletal muscle

Excessive nutrients, especially amino acids, impair insulin action on glucose metabolism in skeletal muscle. We tested the hypothesis that the branched-chain amino acid leucine reduces acute insulin action in primary myotubes via a negative feedback mechanism involving ribosomal protein S6 kinase 1 (S6K1). The effect of S6K1 on glucose metabolism was determined by applying RNA interference (siRNA). Leucine (5 mM) reduced glucose uptake and incorporation to glycogen by 13% and 22%, respectively, compared to the scramble siRNA-transfected control at the basal level. Leucine also reduced insulin-stimulated Akt phosphorylation, glucose uptake and glucose incorporation to glycogen (39%, 39% and 37%, respectively), and this reduction was restored after S6K1 silencing. Depletion of S6K1 enhanced basal glucose utilization and protected against the development of impaired insulin action, in response to excessive leucine. In conclusion, S6K1 plays an important role in the regulation of insulin action on glucose metabolism in skeletal muscle. Received 22 December 2008; received after revision 19 February 2009; accepted 23 February 2009     

Freeze tolerance in the frog,Rana sylvatica

Summary Wood frogs survive extracellular freezing at moderate subzero temperatures (–4°C) for at least 11 days. Freezing survival is aided by the accumulation of high concentrations of glucose as a cryoprotectant in blood and tissues. Glucose production was accompanied by a rapid decline in liver, but not muscle, glycogen levels suggesting that liver is the organ controlling cryoprotectant synthesis.Acknowledgments. This study was supported by grants to L.M.G. from the Kroc Foundation (Santa Ynez, California) and from the National Institute of Dental Research (Grant No. DE-03987). The authors wish to thank K. Yorko, M. Shakin, J. Finan and Mrs N. Manivannan for their technical and secretarial assistance.Acknowledgments. I thank Dr J. Ballantyne, Dr F. Schueler and I. McMurray for help with frog collections and Dr. W. Schmid, Dr J. Bogart and Dr F. Cook for helpful discussions. Supported by an N.S.E.R.C. operating grant and by a grant from the Atkinson Charitable Foundation.     

Circadian rhythmicity in phosphorylase activity and glycogen content in the heart muscle of the scorpion,Heterometrus fulvipes,C.L. Koch

Summary Maximal activity levels of phosphorylase A and AB at 20.00 h alternate with minimal levels at 08.00 h of the day, while the glycogen content exhibited a reverse trend in the heart of the scorpion,Heterometrus fulvipes.Acknowledgment. The authors thank Prof. K.S. Swami, for providing facilities. The financial assistance rendered by UGC (to VJ) and ICMR (to DCR) is gratefully acknowledged.     

On the binding of steroid sulfates to albumin

Summary ³H-Labeled steroid sulfates, sulfate of estrone (E₁S) or dehydroepiandrosterone (DHAS), were dialyzed against delipidated human serum albumin or human plasma in the presence of increasing amounts of competing non-labeled sulfates (DHAS or E₁S). The apparent equilibrium constants (K) of the tracers did not measuraby change at concentrations of the non-radioactive sulfates below 10^–5 mol/l. At higher concentrations, K decreased gradually. The apparent equilibrium constant of³H-E₁S was diminished by plasma in a similar fashion. It may be concluded that albumin possesses one strong, non-specific binding site. This site, however, does not seem to be utilized for the binding of E₁S in vivo, because of its preferetial occupation by other ligands. This may be true for other steroid sulfates as well, depending on their relative abundance in plasma.Acknowledgment. This investigation received financial support from the Special Programme of Research, Development and Research Training in Human Reproduction, World Health Organisation, and from the Ford Foundation.     

Glycogen contents in the rat uterus: Response toHibiscus rosa-sinensis Linn. extracts

Summary Ethanolic extracts (50%), as well the benzene extracts, ofH. rosa-sinensis Linn. have reduced significantly the glycogen contents in the uterus of adult rat. Both the extracts exhibit a clear-cut dose-response relation. The inhibition in glycogen contents increases as the dose is increased. Of the 2, benzene extract seems to be more potent. The results are due to antiestrogenic nature of the extracts.This investigation was supported by a grant from Council of Scientific & Industrial Research, New Delhi.     

Correlation of histochemical and physiological properties of muscle units in the striped skunk

Summary Single motor units in striped skunk medial gastrocnemias were isolated and physiologically characterized. Individual muscle unit fibres tagged by glycogen depletion were analyzed histochemically and found to have histochemical profiles consistently correlated with the physiological findings.This work was supported by the Organized Research Committee, Northern Arizona University.     

A mechanical study of the cat retractor bulbi muscle

Zusammenfassung Die mechanischen Eigenschaften des M. retractor bulbi in der Katze (Anstiegs- und Abfallzeiten der Einzelzuckung und der tetanischen Kontraktion und Fusionsfrequenz) liegen zwischen den Eigenschaften der schnellen und langsamen Zuckungsfasern des M. obliquus inferior.

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This investigation was supported by Public Health Service Program Project Research Grant No. NB 06038, General Research Support Grant No. 5 S01 FR-05566, and Research Career Program Award No. K3-NB-14,094 to Dr.Bach-y-Rita from the National Institute of Neurological Diseases and Blindness.     

Forecasting the economic recession in the U.K. 1979-1982: A comparison of model-based ex ante Forecasts

This paper compares the forecasts of recession and recovery made by five non-government U.K. teams modelling the economy (Cambridge Econometrics, the London Business School, the National Institute of Economic and Social Research, the Cambridge Economic Policy Group and the Liverpool Research Group). The paper concentrates on annual ex ante projections as published over the period 1978-1982, i.e. forecasts made, before the event, of the onset, length, depth and character of the economic recession in the U.K. which began in 1979. The comparison is in terms of year by year changes in production, unemployment, prices and other variables. It concludes that no group was systematically better or worse than other groups (confirming U.S. experience) and that the groups tended to perform better in their chosen areas of specialization, e.g. medium-term groups did better at forecasting the medium-term outcome.     

The electron microscopy of fluorescent dextrans (FITC-dextrans) in thin sections of tissue

Summary Fluorescein-coupled dextrans (FITC-Ds) were detected in sections in the electron microscope using 4 different contrasting methods when tissue was postfixed in osmium tetroxide. Endogeneous glycogen was also stained by the methods used, but FITC-D particles appeared smaller and more irregular, and in other locations. In dextranase treated specimens glycogen was still visible, while FITC-D was not.Acknowledgments. The author is grateful to Susan Max-Jacobsen, Kjeld Stub and Sonja Fich for excellent technical assistance. The author was supported by a research fellowship from the Danish Medical Research Council (12–1688).     

Effect of p-coumaric acid on immature estrogen treated and cyclic female mice

Summary Oral administration of p-coumaric acid to estrogen-primed immature female mice exerts neither estrogenic nor anti-estrogenic activity, but when it is administered to cyclic female mice in single dose at proestrus or in repeated doses, induces alteration in estrus cycle, ovarian and uterine weight and structure.The authors wish to thank Dr S. C. Pakrashi and his associates of Medicinal Chemistry Department for isolating the compound. Thanks are also due for granting Senior Research Fellowship to P.P. and Junior Research Fellowship to S.N.K. respectively.     

Measurement of orientation responses of caterpillars indoors and outdoors on a grid

Summary A method has been developed to measure orientation responeses of caterpillars to various sources of stimuli at predetermined distances on a grid of intersecting ribs indoors and outdoors.The authors are grateful to the University Grants Commission, New Delhi, for grant which partially supported this work and to the Council of Scientific and Industrial Research, New Delhi, for the Junior Research Fellowships to P. K. and S. G.     

Rhythmicity of aminotransferase in the cockroach,Periplaneta americana

Summary Aspartate (AAT) and alanine aminotransferase (AIAT) activities in nervous system and coxal leg muscle of the cockroach showed circadian variations with maximal activity around midnight, alternating with minimal activity at 12.00 noon of the solar day. The enhanced activity levels of the enzymes observed during night dark hours may be related to higher energy requirements during increased locomotor activity of the animals.We thank Prof. K. S. Swami, for providing facilities. The financial help rendered by UGC and CSIR, in the form of Junior (to SV) and Senior (to TPK) Research Fellowships is acknowledged.     

Influence ofBotryodiplodia infection on the ascorbic acid content of two varieties of guava

Zusammenfassung Der Ascorbinsäuregehalt nimmt in reifen Guavafrüchten nach Infektion durchBotryodiploida theobromae rasch ab, was wahrscheinlich auf enzymatischer Oxydation der Ascorbinsäure beruht.

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This research has been financed in part by grant No. P.L. 480, Fg In-133 made by the United States Department of Agriculture, Agricultural Research Service. The authors are thankful to Drs. S. N. Bhargava and A. K. Ghosh for their help.     

On the possible mode of action of neurohormones on cholinesterase activity in the ventral nerve cord of scorpion,Heterometrus fulvipes

Summary It is shown that K_m of ChE is not affected by the neurohormones but V_max is increased and decreased in presence of acceleratory and inhibitory neurohormones respectively. Hence it is suggested that the neurohormones might modulate the enzyme activity by altering the maximal velocities (V_max) rather than affecting the enzyme affinity (K_m) towards the substrate.Acknowledgment. The present study was carried out at S. V. University, Tirupati, A. P. India, and the authors are highly beholden to Prof. K. S. Swami, Head of the Department of Zoology, S. V. University, for his kind help and encouragement. Thanks are also due to the University Grants Commission, New Delhi, India, for placing one of them (N. V.) as a National Research Associate which made the present work possible.     

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.     

A comparative study of tryptophan metabolism in skins and livers of black and albino rats

Summary The skin of black rats contains less tryptophan than the skin of albino rats, possibly because the activity of tryptophan pyrrolase is higher. The opposite is found in liver, possibly because tryptophan pyrrolase activity is lower in the livers of black rats.Acknowledgments. The authors wish to thank Dr S.C. Bhattacharyya and Dr A. K. Barua, Bose Institute, for their interest in the work. The work was supported by the Council of Scientific and Industrial Research, New Delhi.     

Dissociation of separate mechanisms of estrogen action by actinomycin D

Summary Pretreatment with actinomycin D 1 h before estrogen administration completely blocks estrogen-induced increases in uterine RNA and protein content, but does not counteract estrogen-induced uterine eosinophilia, edema and increase in glycogen content.Acknowledgments. This work was supported by the Belgian Ministry of Scientific Policy (Concerted Actions of Research) and by the Servicio de Desarrollo Cientifico, Artistico y de Cooperacion Internacional from the University of Chile.     

Metabolic status of temperature induced swollen conidia ofAspergillus nidulans

Summary There is an active synthesis of DNA, RNA, protein, and carbohydrate in conidia incubated at 48°C. DNA increases more or less 3 times; while RNA, protein and carbohydrate are synthesized at a much faster rate. Conidia do not germinate at this temperature.Acknowledgments. Grateful thanks are due to Professor B. M. Johri for valuable suggestions. R. K. S. acknowledges with thanks a Senior Research Fellowship of the Council of Scientific and Industrial Research, New Delhi.     

Muscle specific structural differences in piscine muscle glycogens

Summary Piscine red muscles are rich in glycogen content. Structurally white muscle glycogens have one glucosidal unit more in their external branches than the red muscles.The author wishes to thank the CSIR, New Delhi for the award of a Junior Research Fellowship.