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1.
Changes in lipid peroxidation, the redox system and ATPase activities in plasma membranes of rice seedling roots caused by lanthanum chloride 总被引:10,自引:0,他引:10
Hai-Lei Zheng Zhong-Qiu Zhao Chun-Guang Zhang Jin-Zhao Feng Zen-Lian Ke Ming-Jia Su 《Biometals》2000,13(2):157-163
Highly purified plasma membranes were isolated by aqueous two-phase partitioning from rice (Oryza sativa) seedling roots. The effects of lanthanum chloride (LaCl3) on the activities of lipid peroxidation, the redox system and H+-ATPase, Ca2+-ATPase of plasma membranes were studied. The lipid peroxidation of plasma membranes could be depressed by certain low concentrations of LaCl3 and enhanced by high concentrations of LaCl3, while the lipid peroxidation was also dependent on the plasma membrane protein and incubation time. The relative activity of O2 uptake of plasma membranes was inhibited by all tested LaCl3 concentrations. In contrast, the reduction rate of Fe(CN)6
3– by plasma membranes was stimulated below 40 M of LaCl3, but was reduced above 60 M of LaCl3. The relative activities of both H+-ATPase and Ca2+-ATPase increased constantly from control to LaCl3 of concentration 60 M where the activities of both enzymes were the maximum, but decreased remarkably at 80 M LaCl3 concentrations various LaCl3 were added to culture solutions. In the other measurement case in which various LaCl3 concentrations were added directly to reaction medium and the plasma membrane vesicles only came from the control cultured rice seedling roots, the response of H+-ATPase activity to La3+ was similar to the response in culture solution. However, the La3+ concentration was only 20 M when the activity of H+-ATPase was the maximum. In contrast to the case of LaCl3 addition to culture solution, Ca2+-ATPase activity was inhibited by all concentrations of La3+ which were added directly to the reaction medium. The above results revealed that REEs inhibited electron transfer from NADH to oxygen in plant plasma membranes, depressed the production of active oxygen radicals, and reduced the formation of lipid peroxides through plasma membrane lipid peroxidation. REEs ions also enhanced the H+ extrusion by both standard redox system and H+-ATPase in plasma membranes at certain concentrations. A possible role for the plant cell wall in REEs effects on plasma membranes was also suggested. 相似文献
2.
La3+ stimulated quiescent Swiss 3T3 and 3T6 ceils to enter the DNA-synthesizing S phase of the cell cycle. La3+ and insulin interacted synergistically to increase DNA synthesis. A brief exposure of the cells to soluble LaCl3 optimally stimulated entry into S. La3+ was similar to Al3+ in its mitogenic properties (J. Cell. Physiol.118 , 298, 1984), but La3+ was 10 times more potent than Al3+. 相似文献
3.
Analytical electron microscopical investigations on the apoplastic pathways of lanthanum transport in barley roots 总被引:5,自引:0,他引:5
In transmission electron microscopy studies, lanthanum ions have been used as electron-opaque tracers to delineate the apoplastic
pathways for ion transport in barley (Hordeum vulgare L.) roots. To localize La3+ on the subcellular level, e.g. in cell walls and on the surface of membranes, electron-energy-loss spectroscopy and electron-spectroscopic
imaging were used. Seminal and nodal roots were exposed for 30 min to 1 mM LaCl3 and 10 mM LaCl3, respectively. In seminal roots, possessing no exodermis, La3+ diffusion through the apoplast was stopped by the Casparian bands of the endodermis. In nodal roots with an exodermis, however,
La3+ diffusion through the cortical apoplast had already stopped at the tight junctions of the exodermal cell walls resembling
the Casparian bands of the endodermis. Therefore, we conclude that in some specialized roots such as the nodal roots of barley,
the physiological role of the endodermis is largely performed by the exodermis.
Received: 28 July 1999 / Accepted: 24 February 2000 相似文献
4.
The heat flux of Tetrahymena thermophila BF5 during growth and the effects of La3+ and Ca2+ on them were investigated with microcalorimetry; simultaneously, morphological changes of T. thermophila were obtained by light microscope. La3+ in low concentration (0–5.0 × 10–4 mol/l) remarkably stimulated T. thermophila metabolism, but high dose of La3+ (5.8–8.6 × 10–4 mol/l) restrained it in a linear manner with IC50 being 7.2 × 10–4 mol/l. In contrast, low concentration of Ca2+ did not manifest obvious stimulation on T. thermophila metabolism; moreover, the IC50 of Ca2+ was much higher than that of La3+. Low concentration of La3+ did not lead to changes in appearance of T. thermophila, but low dose of Ca2+ clearly promoted the cell proliferation. In addition, the morphological changes of T. thermophila evoked by high concentrations of La3+ and Ca2+ were consistent with relevant microcalorimetric results. It is concluded that La and Ca influence T. thermophila via different pathways, and La represents toxic action rather than Ca analogy. 相似文献
5.
Min Fei Na Li Yuguan Ze Jie Liu Xiaolan Gong Yanmei Duan Xiaoyang Zhao Han Wang Fashui Hong 《Biological trace element research》2011,139(1):72-80
In order to study the mechanisms underlying the effects of lanthanoid (Ln) on the liver, ICR mice were injected with LaCl3, CeCl3, and NdCl3 at a dose of 20 mg/kg BW into the abdominal cavity daily for 14 days. We then examined oxidative stress-mediated responses
in the liver. The increase of lipid peroxide in the liver produced by Ln suggested an oxidative attack that was activated
by a reduction of antioxidative defense mechanisms as measured by analyzing the activities of superoxide dismutase, catalase,
and ascorbate peroxidase, as well as antioxidant levels such as glutathione and ascorbic acid, which were greatest in Ce3+ treatment, medium in Nd3+, and least in La3+. Our results also implied that the oxidative stress in the liver caused by Ln likely is Ce3+ > Nd3+ >La3+, but the mechanisms need to be further studied in future. 相似文献
6.
Summary The effects of lanthanum on the activity of purified preparations of acetylcholinesterase (AChE) from the electric organ ofE. electricus and on the activity of AChE in intact electro-plaques from the same species were studied. 0.1mm LaCl3 produced an initial inhibition of purified AChE which was followed by a delayed activation of the enzyme. Upon pretreatment of purified enzyme with LaCl3, initial activity was markedly increased. LaCl3 exerted a marked, concentration-dependent inhibition of intact cell AChE.La3+ and Ca2+ appear to interact competitively. In the presence of both 10mm CaCl2 and 0.1mm LaCl3, the initial activity of purified AChE was increased at lower ACh concentrations and inhibited at ACh concentrations greater than 3 × 10–4
m. Inhibition of intact cell enzyme by 0.1mm LaCl3 was relieved by increasing the CaCl2 concentration to 10mm at ACh concentrations less than 2 × 10–4
m.The data were analyzed assuming Michaelis-Menten kinetics and interpreted with reference to the differential binding of divalent and trivalent cations to regulatory anionic sites which are separate and distinct from the anionic site of the active center of the enzyme. 相似文献
7.
Haiquan Zhao Zhe Cheng Renping Hu Jie Chen Mengmeng Hong Min Zhou Xiaolan Gong Ling Wang Fashui Hong 《Biological trace element research》2011,142(2):174-189
The organ toxicity of lanthanides (Ln) on organisms had been recognized, but very little is known about the oxidative injury
of brain caused by Ln. In order to study the mechanisms underlying the effects of Ln on the brain, ICR mice were injected
with a single 20 mg/kg body weight dose of LaCl3, CeCl3, and NdCl3 into the abdominal cavity daily for 14 days. We then examined the coefficient of the brain, the brain pathological changes
and oxidative stress-mediated responses, and the accumulation of Ln and levels of neurochemicals in the brain. The results
showed that CeCl3 and NdCl3 could induce some neurons to turn inflammatory cells and slight edema but did not observe the brain pathological changes
from LaCl3-treated group. The concentrations of La, Ce, and Nd in the brain were significantly different and ranked in the order of
Ce, Nd, and La. The injury of the brain and oxidative stress occurred as Ln appeared to trigger a cascade of reactions such
as lipid peroxidation, the decreases of the total antioxidation capacity and activities of antioxidative enzymes, the excessive
release of nitric oxide, the increase of glutamic acid, and the downregulated level of acetylcholinesterase activities. Furthermore,
both Ce3+ and Nd3+ exhibited higher oxidative stress and toxicity on brain than La3+, and Ce3+ caused more severe brain injuries and oxidative stress than Nd3+, implying that the differences in the brain injuries caused by Ln might be related to the number of 4f electrons of Ln. 相似文献
8.
Phosphorus fixation in lake sediments using LaCl3-modified clays 总被引:1,自引:0,他引:1
Fourteen types of clay, including soils and sediments from Lake Taihu, were modified by LaCl3, and their abilities of phosphorus (P) sorption (the total P up-taken) and fixation (the unleachable P retained in modified clays) were investigated. Results showed that P sorption rates of LaCl3-modified clays were all higher than 90%, while the fixation rates were raised from 3–14% to 52–95%. Kaolinite was selected to study the pH effect on P sorption and desorption of La3+ from the modified clays. In the pH range of 4–8, P sorption on LaCl3-modified kaolinite could reach over 80%, with a maximum of 97% at pH 5. The desorption rate of La3+ decreased with the increase of pH, which was lower than <0.006% at pH > 6.12. This study may provide a solution for internal P pollution from lake sediments. 相似文献
9.
Effects of Lanthanum on Calcium and Magnesium Contents and Cytoplasmic Streaming of Internodal Cells of Chara corallina 总被引:1,自引:0,他引:1
Zijie Li Zhiyong Zhang Ming Yu Yunlong Zhou Yuliang Zhao 《Biological trace element research》2011,143(1):555-561
Biological and environmental effects of lanthanide series of elements have received much attention recently due to their wide
applications. In this study, effects of La3+ treatments on calcium and magnesium concentrations as well as cytoplasmic streaming of internodal cells of Chara corallina were investigated. At all treatment concentrations (10, 100, and 1,000 μM), La3+ significantly decreased calcium concentrations in the cell-wall fractions after 5-h treatments. Calcium concentrations in
the cell contents and magnesium concentrations in the cell-wall fractions were reduced by 100 and 1,000 μM La3+ treatments. However, cytoplasmic streaming as an indicator of [Ca2+]cyt was only inhibited at the highest La3+ concentration (1,000 μM). The results suggest that La3+ may affect cellular calcium homeostasis by actions other than as a simple Ca2+ antagonist. La3+ could partially compensate for calcium deficiency at certain concentrations. 相似文献
10.
The involvement of extracellular calcium in rhythmic and nyctinasticmovement oi Albizzia lophantha Benth. leaflets has been studiedby testing the effect of LaCl3 and its interaction with thephytochrome control of these movements. A 2h pulse of LaCl3(1050 mM) promotes a loss of rhythmicity, leaving leafletsin an open position, and also overrides the phase shift causedby phytochrome. A 2 h pulse of LaCl3 (1 mM) decreases the amplitudeof rhythmic oscillations but does not promote arhythmicity normodify the phase shift caused by red light. The red light pulseabolishes the damping effect of 1 mM La3+. LaCl3 inhibits nyctinasticclosure and decreases the phytochrome control of nyctinasticclosure. A subsequent supply of CaCl2 (10 to 100 mM) does notreverse La3+ (10 mM) inhibition of closure. Light-induced openingis independent of LaCl, but rhythmic opening in darkness showsdifferent responses to La3+ depending on the time at which La3+is applied. Data suggest that extracellular calcium is requiredfor the closure mechanism and for the expression of rhythmicmovement. It could also be involved in the phytochrome transductionpathway and/or in the linking steps between phytochrome andthe circadian clock. Key words: Albizzia lophantha, calcium, circadian rhythm, lanthanum, phytochrome 相似文献
11.
The effects of La3+ on the antioxidant enzyme activities and the relative indices of cellular damage in cucumber seedling leaves were studied. When cucumber seedlings were treated with low concentrations of LaCl3 (0.002 and 0.02 mM), peroxidase (PO) activity increased, and catalase (CAT) activity was similar to that of control leaves at 0.002 mM La3+ and increased at 0.02 mM La3+, whereas superoxide dismutase (SOD) activity did not change significantly. The increase in the contents of chlorophyll (including chlorophylls a and b), carotenoids in parallel with the decrease in the level of malondialdehyde (MDA) suggested that low concentration of La3+ promoted plant growth. However, except the increase in SOD activity at 2 mM La3+, CAT and PO activities and the contents of pigments decreased at high concentrations of La3+ (0.2 and 2 mM), leading to the increase of MDA content and the inhibition of plant growth. It is suggested that lanthanum ion is involved in the regulation of active oxygen-scavenging enzyme activities during plant growth.__________From Fiziologiya Rastenii, Vol. 52, No. 3, 2005, pp. 338–342.Original English Text Copyright © 2005 by Shi, Chen, Huang.This article was submitted by the authors in English. 相似文献
12.
In order to explore the role of mitochondria in proliferation promotion and/or apoptosis induction of lanthanum, the mutual
influences between La3+ and Ca2+ on mitochondrial permeability transition pore (PTP) opening were investigated with isolated mitochondria from rat liver.
The experimental results revealed that La3+ influence the state of mitochondria in a concentration-dependent biphasic manner. La3+ in nanomolar concentrations, acting as a Ca2+ analog, entered mitochondrial matrix via the RuR sensitive Ca2+ channel and elevated ROS level, leading to opening of PTP indicated by mitochondrial swelling, reduction of ΔΨm and cytochrome c release. Inhibition of PTP with 10 μM CsA attenuated the effects of La3+. However, micromolar concentrations La3+ acted mainly as a Ca2+ antagonist, inhibiting PTP opening induced by Ca2+. We postulated that this action of La3+ on mitochondria through interaction with Ca2+ might be involved in the proliferation-promoting and apoptosis induction by La3+. 相似文献
13.
Hongmei Liu Congcong Zhang Kaixun Huang 《Journal of biological inorganic chemistry》2011,16(5):671-681
Experimental studies have demonstrated that oral administration of lanthanum chloride (LaCl3) inhibits the development of atherosclerosis, but the related mechanism has not been fully elucidated. Oxysterols are toxic
to the vascular endothelial cells which are important in preventing the formation and progression of atheromatous plaque.
In this study, we examined the effect of LaCl3 on oxysterol cholestane-3β,5α,6β-triol (Triol)-induced apoptosis and the related mechanisms in ECV-304 cells, a presumptive
endothelial cell line. Incubation with Triol resulted in apoptosis of ECV-304 cells, as determined by Hoechst 33342 staining,
fluorescein isothiocyanate labeled annexin V/propidium iodide double staining, and the loss of mitochondrial membrane potential.
Triol activated extracellular-signal-regulated kinase (ERK) and nuclear factor κB (NF-κB), and inhibition of Triol-activated
ERK and NF-κB signaling by specific inhibitors attenuated apoptosis induction by Triol in ECV-304 cells. Pretreatment with
LaCl3 (1 μM) for 12 h before exposure to Triol decreased Triol-mediated apoptosis as well as activation of ERK and NF-κB. In addition,
Triol induced oxidative stress in ECV-304 cells, manifested by the increase of intracellular reactive oxygen species generation
and malondialdehyde level, and the reduction of the content of total protein thiols and the activity of antioxidant glutathione
peroxidases; LaCl3 pretreatment significantly reversed these effects. Finally, LaCl3 pretreatment significantly inhibited the increases of intracellular Ca2+ concentration induced by Triol. Our study suggests that Triol induced ECV-304 cell apoptosis, and LaCl3 could suppress this effect probably by inhibiting intracellular Ca2+ concentration elevation, oxidative stress, as well as activation of ERK and NF-κB signaling pathways. 相似文献
14.
The effects of phosphorus, Zn2+, CO2, and light intensity on growth, biochemical composition, and the activity of extracellular carbonic anhydrase (CA) in Isochrysis galbana were investigated. A significant change was observed when the concentration of phosphorus in the medium was increased from
5 μmol/L to 1000 μmol/L affecting I. galbana’s cell density, biochemical composition, and the activity of extracellular CA. Phosphorous concentration of 50 μmol/L to 500
μmol/L was optimal for this microalgae. The Zn2+ concentration at 10 μmol/L was essential to maintain optimal growth of the cells, but a higher concentration of Zn2+ (≥ 1000 μmol/L) inhibited the growth of I. galbana. High CO2 concentrations (43.75 mL/L) significantly increased the cell densities compared to low CO2 concentrations (0.35 mL/L). However, the activity of extracellular CA decreased significantly with an increasing concentration
of CO2. The activity of extracellular CA at a CO2 concentration of 43.75 mL/L was approximately 1/6 of the activity when the CO2 concentration was at 0.35 mL/L CO2. Light intensity from 4.0 mW/cm2 to 5.6 mW/cm2 was beneficial for the growth, biochemical composition and the activity of extracellular CA. The lower and higher light intensity
was restrictive for growth and changed its biochemical composition and the activity of extracellular CA. These results indicate
that phosphorus, Zn2+, CO2, and light intensity are important factors that impact growth, biochemical composition and the activity of extracellular
CA in I. galbana. 相似文献
15.
Larry M. Gordon Richard D. Sauerheber Judy A. Esgate 《Journal of cellular biochemistry》1978,9(3):299-326
The structures of rat liver and heart plasma membranes were studied with the 5-nitroxide stearic acid spin probe, I(1 2,3). The polarity-corrected order parameters (S) of liver and heart plasma membranes were independent of probe concentration only if experimentally determined low I(1 2,3)/lipid ratios were employed. At higher probe/lipid ratios, the order parameters of both membrane systems decreased with increasing probe concentration, and these effects were attributed to enhanced nitroxide radical interactions. Examination of the temperature dependence of approximate and polarity-corrected order parameters indicated that lipid phase separations occur in liver (between 19° and 28°C) and heart (between 21° and 32°C) plasma membranes. The possibility that a wide variety of membrane-associated functions may be influenced by these thermotropic phase separations is considered. Addition of 3.9 mM CaCl2 to I(1 2,3)-labeled liver plasma membrane decreased the fluidity as indicated by a 5% increase in S at 37°C. Similarly, titrating I(1 2,3)-labeled heart plasma membranes with either CaCl2 or LaCl3 decreased the lipid fluidity at 37°C, although the magnitude of the La3+ effect was larger and occurred at lower concentrations than that induced by Ca2+; addition of 0.2 mM La3+ or 3.2 mM Ca2+ increased S by approximately 7% and 5%, respectively. The above cation effects reflected only alterations in the membrane fluidity and were not due to changes in probe–probe interactions. Ca2+ and La3+ at these concentrations decrease the activities of such plasma membrane enzymes as Na+, K+-ATPase and adenylyl cyclase, and it is suggested that the inhibition of these enzymes may be due in part to cation-mediated decreases in the lipid fluidity. 相似文献
16.
17.
We tried to determine the mechanisms by which Ca2+ mediated NO-induced programmed cell death (PCD) in tobacco protoplasts. Treatment of tobacco protoplasts with the NO donor
sodium nitroprusside (SNP) resulted in a rapid [Ca2+]cyt accumulation and decrease in mitochondrial membrane potential (ΔΨm) before the appearance of PCD. NO-induced PCD could be largely prevented not only by NO scavenger c-PTIO, but also by EGTA
(Ca2+ chelator), LaCl3 (Ca2+-channel blocker) or CsA (a specific mitochondrial permeability transition pore inhibitor, which also inhibit Ca2+ cycling by mitochondria). All results suggested that NO-induced PCD is mediated through mitochondrial pathway and regulated
by Ca2+. 相似文献
18.
Effect of lanthanum ions (La3+) on the reactive oxygen species scavenging enzymes in wheat leaves 总被引:1,自引:0,他引:1
Physiological effects of lanthanum ions on the activities of the enzymes in the reactive oxygen species (ROS) scavenging system
in leaves of wheat (Triticum aestivum L.) seedlings were studied. Wheat leaves treated in Hogland solution with 0.1 mM LaCl3 for 48 h showed increased levels of superoxide dismutase (SOD), catalase (CAT), ascorbate-specific peroxidase (AsA-POD),
and dehydroascorbate reductase (DHAR). However, a minor effect was observed on the levels of monodehydroascorbate reductase
(MDAR) and glutathione reductase (GR), which regulate the release of energy required by the ROS scavenging system. The whole
system was linked up by H+ transmission. Our results indicated that the activities of the enzymes that function directly to remove ROS were elevated
by La3+ treatment, which is consistent with the observations that La3+-treated plants had increased tolerance to environmental stresses. The remaining levels of MDAR and GR suggested that these
two enzymes might be regulated differently from that of the other four enzymes studied. 相似文献
19.
Enhancement of Lanthanum (III) on Sodium Currents in Acutely Isolated Hippocampal CA1 Neurons of Rat
The effects of lanthanum (III) (La3+) on voltage-gated sodium channel currents (I
Na) in freshly dissociated rat hippocampal CA1 neurons were studied using the whole-cell patch clamp techniques. La3+ reversibly enhanced I
Na in a concentration- and voltage-dependent manner. The 50% enhancement concentration (EC50) of La3+ on I
Na was 9.93 μM. In addition, 10 μM La3+ shifted the steady state activation curve of I
Na towards positive potential and the steady state inactivation curve towards negative potential without changing the slope
factor. These results indicated that La3+ could increase the amplitudes of I
Na and change the activation and inactivation courses of I
Na even in very low concentration. 相似文献
20.
Magdalena Ehrström L.E.Göran Eriksson Jacob Israelachvili Anders Ehrenberg 《Biochemical and biophysical research communications》1973,55(2):396-402
The effects of CaCl2, MgCl2, LaCl3 and some alkali halides on cytoplasmic membranes were studied using stearic acid spin labels. The results indicate that two mechanisms are operating when these ions interact with membranes. At low ionic concentrations (0 to 0.1 M) there is direct cation binding to the anionic membranes which in the case of Ca2+, Mg2+ and La3+, confers rigidity on the membranes and reaches saturation when the number of cations present equals the number of anionic sites on the lipids. At high concentrations there is a further effect on the membranes that parallels the known organizing/disorganizing effects that the ions studied have on water structure. 相似文献