Investigation of mercury metallothionein complexes in tissues of rat after oral intake of HgCl2

Abstract

Mercury, a highly toxic metal found widely throughout the environment, is a potent inducer of metallothionein (MT) expression. The role of MTs in the detoxification of mercury after its oral intake in mammals is studied. After feeding rats with mercuric chloride by gastric gavage, the distribution of heavy metals in rat tissues was investigated by inductively coupled plasma mass spectrometry (ICP-MS). Extensive accumulation of mercury, copper and zinc in kidney and liver is observed. A homemade preparative size-exclusion chromatography (SEC) column (30cm x 1.9cm) packed with Sephadex G-75 (40-120 mum particle size) gel (Pharmacia) was used for the purification of NIT fractions in rat tissues. Preliminary results from SEC indicate that the mercury-binding MT levels in liver were much lower than in kidney. The NIT fractions were collected, desalted, and then separated by reversed-phase high-performance liquid chromatography (HPLC) with UV-Vis spectrometry, ICP-MS and electrospray ionization MS detection. One major and several minor peaks were observed in the HPLC chromatograms of the MT fraction for the kidney sample. UV absorption spectra indicate that MTs were found to bind with mercury. There were no significant mercury-binding MTs detected in the liver sample using UV detection. ICP-MS detection showed that mercury-binding MTs in kidney contained large amounts of mercury and copper but little zinc. Further characterization with ESI-MS showed that the major peak found in kidney contained Hg6Cu, Hg5Cu2-MT-2c and Hg-6-MT-2beta, Hg6Cu-MT-1gamma, Hg-7-MT-2alpha. However, distinction between copper and zinc could not be made based on current mass spectrometric analysis because of instrumental resolution limitations. Copyright (C) 2004 John Wiley Sons, Ltd

A sensitive negative-ion electrospray ionization mass spectrometry detection for metallothionein in tris(hydroxymethyl)aminomethane acetate buffer

“…The second was to find an effective buffer system to maintain a neutral condition and for a sensitive NI-MS detection for MTs. Buffers beyond ammonium acetate and ammonium bicarbonate, which are popularly used, would be taken into consideration since they were found to ineffective to the MS detection [20,23]. TRIS buffer is popularly used to maintain a physiologic condition, which is crucial in the studying of weakly bound, non-covalent complexes.…”

Changes in the oxidative status and damage by non-essential elements in the digestive gland of the gastropod Pomacea canaliculata

“…It is likely that this cellular response is associated with the affinities of Hg, As, and U for different functional biological groups or with different degrees of effectiveness of antioxidant defenses. Inorganic Hg and As have a high affinity for reduced sulfur groups ( Sharma et al, 1993 ; Quig, 1998 ; Ravichandran, 2004 ; Shen et al, 2005 ; Maltez et al, 2009 ), depleting intracellular reserve of thiols ( Valko et al, 2005 ). Furthermore, As and U (in the form of uranyl ion) are prooxidant elements that may respectively increase the superoxide anion and hydrogen peroxide levels ( Shi et al, 2004 ), hydroxyl radicals, and hydrogen peroxide ( Garmash et al, 2014 ), thus producing oxidative stress and macromolecules damage ( Barescut et al, 2005 ; Bergmann et al, 2018 ).…”

Bioindication of mercury, arsenic and uranium in the apple snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Bioconcentration and depuration in tissues and symbiotic corpuscles

“…Hg (class B) has a high affinity for reduced sulfur groups of aquatic ecosystems (Ravichandran, 2004;Sharma et al, 1993) (i.e. Maltez et al, 2009Quig, 1998;Shen et al, 2005). As (intermediate class) has affinity for sulfur and oxygen groups present in natural minerals (Bostick et al, 2003;Gao and Mucci, 2001;Saada et al, 2003) and in cellular metallothioneins (Albores et al, 1992;Diniz et al, 2007;Merrifield et al, 2004); U (class A) has a high affinity for phosphates groups of sources of environmental water and of animal's tissues and organs (Hursh and Spoor, 1973;Kurttio et al, 2005).…”