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1.
Copper- and arsenate-induced oxidative stress in Holcus lanatus L. clones with differential sensitivity 总被引:5,自引:0,他引:5
The biochemical responses of Holcus lanatus L. to copper and arsenate exposure were investigated in arsenate‐tolerant and ‐non‐tolerant plants from uncontaminated and arsenic/copper‐contaminated sites. Increases in lipid peroxidation, superoxide dismutase (SOD) activity and phytochelatin (PC) production were correlated with increasing copper and arsenate exposure. In addition, significant differences in biochemical responses were observed between arsenate‐tolerant and ‐non‐tolerant plants. Copper and arsenate exposure led to the production of reactive oxygen species, resulting in significant lipid peroxidation in non‐tolerant plants. However, SOD activity was suppressed upon metal exposure, possibly due to interference with metallo‐enzymes. It was concluded that in non‐tolerant plants, rapid arsenate influx resulted in PC production, glutathione depletion and lipid peroxidation. This process would also occur in tolerant plants, but by decreasing the rate of influx, they were able to maintain their constitutive functions, detoxify the metals though PC production and quench reactive oxygen species by SOD activity. 相似文献
2.
R Liang 《Biochemical and biophysical research communications》1984,120(3):741-746
Primary cell cultures were prepared from breast muscles of 11 day 4 hour-embryonic chicks. Cytoplasmic RNAs were isolated from the cultured cells at various time intervals from day 3 to day 8. A [P32] DNA probe complementary to messenger RNA of myosin heavy chain was used to hybridize with the RNAs after gel electrophoresis. A transient species of polyadenylated RNA with a decreased mobility in electrophoresis was detected during a period of time when contractions of syncytial fibers were first observed. 相似文献
3.
A new brain protein is described which forms an insoluble complex with tubulin, with concomitant stoichiometric hydrolysis of GTP. The complex contains a maximum of one tubulin-binding protein (MW 52,500) per two tubulin dimers. The tubulin-binding protein (TBP) does not compete with colchicine, but in the presence of microtubule-associated proteins tubulin appeared less accessible to it. Proteins such as TBP might sequester tubulin and thereby function either to inhibit indiscriminate polymerization, or to promote ordered nucleation by maintaining high local concentrations. 相似文献
4.
A review of in vitro mutagenesis assessment of metal compounds in mammalian and nonmammalian test systems has been compiled.
Prokaryotic assays are ineffective or inconsistent in their detection of most metals as mutagens, with the notable exception
of hexavalent chromium. Mammalian assay systems appear to be similarly inappropriate for the screening of metal compounds
based upon the limited number of studies that have employed those compounds having known carcinogenic activity. Although of
limited value as screening tests for the detection of potentially carcinogenic metal compounds, the well-characterized in
vitro mutagenesis systems may prove to be of significant value as a means to elucidate mechanisms of metal genotoxicity. 相似文献
5.
《Journal of molecular biology》2021,433(4):166764
Apical sodium-dependent bile acid transporter (ASBT) catalyses uphill transport of bile acids using the electrochemical gradient of Na+ as the driving force. The crystal structures of two bacterial homologues ASBTNM and ASBTYf have previously been determined, with the former showing an inward-facing conformation, and the latter adopting an outward-facing conformation accomplished by the substitution of the critical Na+-binding residue glutamate-254 with an alanine residue. While the two crystal structures suggested an elevator-like movement to afford alternating access to the substrate binding site, the mechanistic role of Na+ and substrate in the conformational isomerization remains unclear. In this study, we utilized site-directed alkylation monitored by in-gel fluorescence (SDAF) to probe the solvent accessibility of the residues lining the substrate permeation pathway of ASBTNM under different Na+ and substrate conditions, and interpreted the conformational states inferred from the crystal structures. Unexpectedly, the crosslinking experiments demonstrated that ASBTNM is a monomer protein, unlike the other elevator-type transporters, usually forming a homodimer or a homotrimer. The conformational dynamics observed by the biochemical experiments were further validated using DEER measuring the distance between the spin-labelled pairs. Our results revealed that Na+ ions shift the conformational equilibrium of ASBTNM toward the inward-facing state thereby facilitating cytoplasmic uptake of substrate. The current findings provide a novel perspective on the conformational equilibrium of secondary active transporters. 相似文献
6.
The accumulation of heavy metals in Typha latifolia L. grown in a stream carrying secondary effluent
Typha latifolia L. from aquatic plants is widely found throughout Kehli Stream (Elazig, Turkey). This study examined the uptake of some metals by T. latifolia and the transfer from roots to other plant parts. The accumulation of Mn in T. latifolia L. can be suggested as a tolerance strategy due to its transfer factor higher than 1.0. The enrichment coefficients in the leaves of T. latifolia L. were higher than 1.0 for Zn and Mn and often lower than 1.0 for other metals. Similarly, the enrichment coefficients of all metals, except for Cr, in roots of T. latifolia L. were higher than 1.0. This study demonstrated that T. latifolia L. could be considered as either a bio-indicator or a bio-accumulator for sediments and water polluted by metals. 相似文献
7.
Annette Graham 《Free radical research》1998,28(6):611-621
Compelling evidence suggests that low-density lipoprotein (LDL) is oxidized by cells within the arterial intima and that, once oxidized, it is profoundly atherogenic. The precise mechanism(s) by which cells promote the oxidation of LDL in vivo are not known; in vitro, however, oxidation of LDL can be enhanced by a number of differing mechanisms, including reaction with free and protein-bound metal ions, thiols, reactive oxygen species, lipoxygenase, myeloperoxidase and peroxynitrite. This review is concerned with the mechanisms by which cells enhance the oxidation of LDL in the presence of transition metals; in particular, the regulation, pro- and anti-oxidant consequences, and mechanism of action of cellular thiol production are examined, and contrasted with thiol-independent oxidation of LDL in the presence of transition metals. 相似文献
8.
A simple method is described for picomole determinations of fatty acid metal salts. Fatty acid salts are directly labeled with 4-bromomethyl-7-methoxycoumarin in the presence of excess ethylenediaminetetraacetic acid tripotassium salt without any solvent extractions. The fluorescence derivatives of fatty acids are separated by reverse-phase high-performance liquid chromatography followed by fluorometric detection. The response of each fatty acid (C8-C18) calcium salt is linear from 1 to 50 micrograms/ml of samples. The detection limit is about 7 pmol. Good recoveries are obtained for the calcium salts of myrystic acid and soap (C8-C18, C18:1,2). The new method is successfully applied to the study on biodegradation of fatty acids in river water. 相似文献
9.
10.