Search results for "Trace"

Dysfunction of Torr causes a Harlequin-type ichthyosis-like phenotype in Drosophila melanogaster

2019

AbstractPrevention of desiccation is a constant challenge for terrestrial organisms. Land insects have an extracellular coat, the cuticle, that plays a major role in protection against exaggerated water loss. Here, we report that the ABC transporter Torr - a human ABCA12 paralog - contributes to the waterproof barrier function of the cuticle in the fruit fly Drosophila melanogaster. We show that the reduction or elimination of Torr function provokes rapid desiccation. Torr is also involved in defining the inward barrier against xenobiotics penetration. Consistently, the amounts of cuticular hydrocarbons that are involved in cuticle impermeability decrease markedly when Torr activity is redu…

2002

Previous observations have suggested a role for nitric oxide in the activity of the globus pallidus, but this functional involvement has not yet been tested in vivo. The extracellular activity of single units of the globus pallidus was recorded, and neuronal nitric oxide synthase was inhibited by systemically administering 7-nitro-indazole to a group of anaesthetised rats. Forty-five per cent of cells responded with a decrease in the firing rate. In another group of rats, the microiontophoretic administration of 3-morpholino-sydnonimin-hydrocloride (a nitric oxide donor) induced an increase in neuronal firing rate (24/28 cells), whereas the administration of Nω-nitro-L-arginine methyl ester…

Onset of DNA synthesis in experimentally activated ascidian eggs

1994

DNA synthesis was studied autoradiographically in unfertilized ascidian eggs (Ascidia malaca and Ciona intestinalis) that had been artificially activated by a K+-free external medium or a Ca-ionophore. Naked eggs of A. malaca were incubated in K+-free seawater that contained [3H]-thymidine for 30 min, and naked eggs of C. intestinalis were incubated in seawater supplemented with a Ca-ionophore and [3H]-thymidine for 15 min. The observations revealed limited activation in eggs treated with K+-free seawater. Activation consisted of surface modifications and the onset of DNA synthesis. Incorporation of [3H]-thymidine was detected in female nuclei of treated eggs which had not ejected their pol…

Hypoxia-Induced Extracellular Acidosis Increases p-Glycoprotein Activity and Chemoresistance in Tumors in Vivo via p38 Signaling Pathway

2011

Due to inadequate perfusion, tumors develop hypoxia and extracellular acidosis. In vitro, this acidic environment (pH=6.6) has a strong impact on the acitvity of the p-glycoprotein (pGP) drug transporter responsible for multidrug resistance. This effect is most probably mediated via p38 and/or ERK1/2 signalling pathways. The aimof the studywas to analyzewhether these findings also play a role for chemosensitivity in solid growing tumors in vivo. Therefore, experimental R3327-AT1 tumors of the rat were exposed to an acidifying treatment leading to forced glycolysis. The intratumoral pO21 was determined polarographically and the extracellular pH was measured with needle electrodes. In additio…

DNA barcoding for Arecaceae and Fabaceae species identification of two plant collections

2021

DNA barcoding is a well-known technique that enable species identification by using universal DNA sequences from a small fragment of the genome. In this work, the effectiveness of DNA barcoding approach was evaluated in order to identify different taxonomic groups among two families (Arecaceae and Fabaceae) from two flowering plant collections: some were economically important taxa from nursery production and Mediterranean plants with ornamental attitude for possible new introduction. Three chloroplast DNA barcode regions (matK, rbcL and trnH-psbA) proposed by the Consortium for the Barcode of Life (CBOL) were tested in 22 Arecaceae species and in eight Fabaceae species, including Ceratonia…

Isotope Fractionation of Selenium During Fungal Biomethylation by Alternaria alternata

2011

The natural abundance of stable Se isotopes may reflect sources and formation conditions of methylated Se. We aimed at (1) quantifying the degree of methylation of selenate [Se(VI)] and (hydro)selenite [Se(IV)] by the fungus Alternaria alternata at pH 4 and 7 and (2) determining the effects of these different Se sources and pH values on 82Se/76Se ratios (δ82/76Se) in methylselenides. Alternaria alternata was incubated with Se(VI) and Se(IV) in closed microcosms for 11-15 days and additionally with Se(IV) for 3-5 days at 30 °C. We determined Se concentrations and δ82/76Se values in source Se(VI) and Se(IV), media, fungi, and trapped methylselenides. In Se(VI) incubations, methylselenide vola…

Differences in Attachment and Phagocytosis of Salmonella minnesota Strains (S Form, Re Mutant) by Mouse Peritoneal Macrophages: Participation of Endo…

1985

The virulence of bacteria in many phagocytic systems has been studied for several years and it is known that macrophages play an important role in host defence against invading microorganisms and in cooperation with cellular and humoral immune mechanisms. Pathogenic bacteria can be divided into two groups with regard to their fate within phagocytes: (a) extracellular bacteria which are promptly killed after phagocytosis and (b) facultative intracellular bacteria which are resistant to intracellular killing unless macrophages are activated. Humoral immune mechanisms (antibody, complement) deal mainly with extracellular bacteria, while cellular immune mechanisms (T cells, macrophages) deal wi…

Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica …

2010

The element chemistry of biogenic carbonates can provide important data on past environments. However, the Sr/Ca and Mg/Ca ratios as well as the Mg and Sr concentrations of biological carbonates, especially aragonitic bivalves often depart from apparent thermodynamic equilibrium. When measured in situ by means of LA-ICP-MS, the Mg concentration is often substantially enriched (two- to threefold) near the organic-rich, annual growth lines. To test the hypothesis that some organic components exert a major influence on the skeletal metal content, the element chemistry of different shell components (insoluble organic matrix, IOM; dissolved CaCO3 and soluble organics, SOM) of Arctica islandica w…

[9] Identification of carrier systems in plasma membranes of mammalian cells involved in transport of l-arginine

1999

Publisher Summary This chapter describes the transport systems and the corresponding carrier proteins involved in the L-arginine transport that have been described till date. The chapter also discusses the methods that have been used to characterize L-arginine transport in nitric oxide (NO) producing cells or tissues. L-arginine transport is mediated by multiple carrier systems, some of which have not yet been identified at a molecular level. It is conceivable that a modification of a carrier or an associated protein could alter its transport activity, resulting in the appearance of a carrier with altered transport characteristics. Considerable progress has been made in identifying cationic…

Electron microscopy and biochemical characterization of a 350-kDa annular hemolymph protein from the keyhole limpet Megathura crenulata

1994

The isolation and biochemical characterization of an annular non-hemocyanin hemolymph protein from a marine gastropod, the Californian giant keyhole limpet (Megathura crenulata) is presented. By analytical ultracentrifugation, the protein has a sedimentation coefficient of 12S and molecular mass of approximately 350 kDa. The subunit mass, obtained by SDS/PAGE in the presence of -SH reagent and 8 M urea, is approximately 35 kDa, thereby indicating the presence of 10 subunits in the native molecule. By negative staining, the protein is revealed in one predominant image projection as a pentagonal approximately 8 nm ring-like structure with an approximately 2-nm stain-filled centre and, in anot…