Acid phosphatases in the tea leaf

Résumé Les isozymes des phosphatases acides de la feuille du thé ont été séparés par électrophorèse et localisés par une méthode histochimique.     

The carbohydrate metabolism accompanying intoxication by aluminium salts in the rat

Zusammenfassung Bei Intoxikation von Versuchsratten durch Aluminiumsalze wurden Störungen im Glyzid-Metabolismus festgestellt. Er ergab sich ein Glykogenrückfall in Leber und Muskelgewebe und eine Erhöhung des Brenztraubensäure- und Milchsäurespiegels. Es wird angenommen, dass die beobachteten Veränderungen mit Störungen des Phosphormetabolismus und der Phosphorilationsreaktionen durch die Aluminiumtoxikation zusammenhängen.     

Receptor and nonreceptor protein tyrosine phosphatases in the nervous system

Protein tyrosine phosphatases (PTPs) have emerged as a new class of signaling molecules that play important roles in the development and function of the central nervous system. They include both tyrosine-specific and dual-specific phosphatases. Based on their cellular localization they are also classified as receptor-like or intracellular PTP. However, the intracellular mechanisms by which these PTPs regulate cellular signaling pathways are not well understood. Evidence gathered to date provides some insight into the physiological function of these PTPs in the nervous system. In this review, we outline what is currently known about the functional role of PTPs expressed in the brain.Received 31 March 2003; received after revision 7 May 2003; accepted 22 May 2003     

Comparison of the inhibition of avian and mammalian bone alkaline phosphatases by levamisole and compound R8231

Summary Alkaline phosphatases from mammalian bone are inhibited much more than chick bone alkaline phosphatase by levamisole and compound R8231. Doses of R8231 (10^–4 to 10^–5 M) that almost completely inhibit mammalian alkaline phosphatases do not inhibit the growth of embryonic rat femurs in vitro. R8231 should be an excellent biological probe for the function of alkaline phosphatase in bone metabolism.Acknowledgments. This work has been supported by funds from the Medical Research Council.     

Selectivity of carbohydrate films as influenced by their moisture content

Zusammenfassung Der Einfluss des Wassergehaltes auf die beim Trocknen pflanzlicher Säfte und Extrakte an der Flüssigkeitsoberfläche sich bildende, nahezu trockene, hydrophile Haut wurde untersucht.     

Unique occurrence of fenchol in the animal kingdom

Summary (–)--Fenchol, a compound occurring in plants but not heretofore reported to occur in an animal product, was isolated from volatiles released by adult male Mediterranean fruit flies,Ceratitis capitata Wiedemann, with the male's previously identified sex pheromones. It neither attracts females nor synergizes the pheromones, and its function remains unknown.The editors do not hold themselves responsible for the opinions expressed in the authors' brief reports. — Les auteurs sont seuls responsables des opinions exprimées dans ces brèves communications. — Für die Kurzmitteilungen ist ausschliesslich der Autor verantwortlich.—Per le brevi comunicazioni è responsabile solo l'autore. — . — Solo los autores son responsables de las opiniones expresadas en estas communicationes breves.Mention of a proprietary product in this paper does not constitute a recommendation or an endorsement of the product by the US Department of Agriculture.Acknowledgments. We thank C. Harding for assistance with extractions and fractionations, R.M. Waters for spectral analyses, M.S. Fujimoto and H. Higa for collecting the volatiles and conducting laboratory and cage bioassays, and T. Urago and S. Nakagawa for conducting the field tests.     

Localization of acid phosphatases in the cell fractions of chick liver

Summary 3 molecular forms (P1, P2 and P3) of acid phosphatase (E.C.3.1.3.2) have been detected in chicken liver homogenate. The different intracellular localization of these molecules has been demonstrated by cellular fractionation and electrophoretic analysis. P1 and P2 phosphatases are both present in the particulate fraction. P3 is present in a pure form in the soluble fraction. The difference between the enzyme molecules present in the particulate fraction and that in the soluble one is confirmed by the different activation-inhibition effect of various ions and substances on the enzymatic activity of subcellular fractions.     

On the carbohydrate utilization by the larvae ofTrogoderma granarium everts. (Dermestidae: Coleoptera)

Zusammenfassung Trogoderma-Larven reagieren auf verschiedenartige Kohlehydrate verschieden. Disaccharide erweisen sich als die besten, Trisaccharide, Stärke und Hexosen als ziemlich gute, Pentosen und Zuckeralkohole als sehr schlechte Kohlehydratquellen.     

Modulation of protein kinases and phosphoprotein phosphatases by a small acidic protein from bovine brains

Summary A small, acidic and heat-stable protein was purified from bovine brains by column chromatography on DEAE-cellulose, Bio-Gel HTP, Affi-Gel phenothiazine and Sephadex G-75. This protein stimulates megamodulin-dependent protein kinase I from brains and phosphoprotein phosphatases from either brain or yeast. However, it inhibits cyclic AMP-dependent protein kinases from skeletal muscle.Acknowledgments. This work was supported by a grant (RR-08229) from the National Institutes of Health, USA. W.N. Kuo is a recipient of a Distinguished Faculty Scholar Award from United Negro College Fund, Inc., USA.     

Regulation of carbohydrate metabolism by the optic tentacles of the garden snailCryptozona ligulata (Gastropoda-Stylommatophora)

Summary The presence of a hyperglycemic factor in the optic tentacles of the snailC. ligulata is reported here. A preliminary characterization based on crude extracts indicates the factor to be water-soluble, heat labile and to be an albumin. The ablation of optic tentacles and injection of optic tentacle extract into operated and normal snails caused a rise in blood sugar, total carbohydrate and glycogen in the foot muscle and mantle and a decrease in hepatopancreatic glycogen. The ablation also caused a fall in blood free amino acids and a rise in the tissues, which was reversed in the blood and foot muscle by injection of the extract. Possible conversion of amino acids to total carbohydrates and glycogen by gluconeogenesis is suggested.     

Modulation of protein kinases and phosphoprotein phosphatases by a small acidic protein from bovine brains

A small, acidic and heat-stable protein was purified from bovine brains by column chromatography on DEAE-cellulose, Bio-Gel HTP, Affi-Gel phenothiazine and Sephadex G-75. This protein stimulates megamodulin-dependent protein kinase I from brains and phosphoprotein phosphatases from either brain or yeast. However, it inhibits cyclic AMP-dependent protein kinases from skeletal muscle.     

Implication of phosphoinositide phosphatases in genetic diseases: the case of myotubularin

Phosphoinositides play a central role in the control of major eukaryotic cell signaling mechanisms. Accordingly, the list of phosphoinositide-metabolizing enzymes implicated in human diseases has considerably increased these last years. Here we will focus on myotubularin, the protein mutated in the X-linked myotubular myopathy (XLMTM) and the founding member of a family of 13 related proteins. Recent data demonstrate that myotubularin and several other members of the family are potent lipid phosphatases showing a marked specificity for phosphatidylinositol 3-phosphate [PtdIns(3)P]. This finding has raised considerable interest as PtdIns(3)P is implicated in vesicular trafficking and sorting through its binding to specific protein domains. The structure of myotubularin, the molecular mechanisms of its function and its implication in the etiology of XLMTM will be discussed, as well as the potential function and role of the other members of the family.Received 14 February 2003; received after revision 10 April 2003; accepted 14 April 2003     

Unique gene structure and paralogy define the 7D-cadherin family

Cadherins are Ca²⁺-dependent transmembrane glycoproteins crucial for cell-cell adhesion in vertebrates and invertebrates. Classification of this superfamily due to their phylogenetic relationship is currently restricted to three major subfamilies: classical, desmosomal and protocadherins. Here we report evidence for a common phylogenetic origin of the kidney-specific Ksp- (Cdh16) and the intestine-specific LI-cadherin (Cdh17). Both genes consist of 18 exons and the positions of their exon-intron boundaries as well as their intron phases are perfectly conserved. We found an extensive paralogy of more than 40 megabases in mammals as well as teleost fish species encompassing the Ksp- and LI-cadherin genes. A comparable paralogy was not detected for other cadherin gene loci. These findings suggest that the Ksp- and LI-cadherin genes originated by chromosomal duplication early during vertebrate evolution and support our assumption that both proteins are paralogues within a separate cadherin family that we have termed 7D-cadherins. Received 16 January 2006; received after revision 18 April 2006; accepted 11 May 2006     

Neuroendocrine control of carbohydrate metabolism in the freshwater bivalve molluscLamellidens marginalis

Summary Blood sugars and foot muscle glycogen were measured in the mussel,L. marginalis after ablation of the cerebral ganglia, and in mussels injected with cerebral ganglionic extract 3 h after ablation. There is a rise in the blood sugar and decrease in foot muscle glycogen 3 h after operation, but no change in sham-operated controls. The effect of ablation is reversed by injecting brain extract into ablated mussels. No such effect could be seen in the controls. The results are suggestive of the presence, in the cerebral ganglia, of a hypoglycaemic factor similar to insulin.     

Effect of Progesterone on the in vivo binding of estrogens by uterine cells

Summary Progesterone selectively inhibits estradiol upltake by the nuclei of the luminal epithelial cells but not by other uterine cells. This inhibition in estrogen binding parallels the inhibition by progesterone of some estrogenic responses in the luminal epithelial cells only.Acknowledgments. This work was supported by Grant No. 2015 From the Oficina Técnica de Desarrollo Cientifico y Creación Artística of the University of Chile.     

Evidence of soluble proteins binding adriamycin by affinity chromatography

Summary The presence in various tissues of soluble proteins binding adriamycin is evidenced by affinity chromatography.     

Dynamics of estrogen binding by uterine cells in vivo

Summary The dynamics of the in vivo binding and release of tritiated estradiol in different uterine cell types are described. The very early binding of estrogens by the cytosol-nuclear and the eosinophil receptor systems is in accordance with the hypothesis that some estrogenic effects are mediated by these receptor systems.Acknowledgments. This work was supported in part by grant 2015 from the Servicio Técnico de Desarrollo Científico y Creación Artística of the University of Chile to the Laboratory of Experimental Endocrinology, Department of Experimental Morphology, University of Chile Medical School, by a Population Council Fellowship to Dr A. Tchernitchin from 1970 to 1972, by a Rockefeller Foundation grant to the Laboratories of Reproductive Biology, University of North Carolina Medical School, and by USPHS grant HD00371 to the Children's Hospital of Philadelphia. We wish to thank Drs W. E. Stumpf (Laboratories of Reproductive Biology, University of North Carolina Medical School) and A. M. Bongiovanni (Children's Hospital of Philadelphia) for the facilities available.