共查询到20条相似文献,搜索用时 46 毫秒
1.
Water loss either by desiccation or freezing causes multiple forms of cellular damage. The encysted embryos (cysts) of the crustacean Artemia franciscana have several molecular mechanisms to enable anhydrobiosis—life without water—during diapause. To better understand how cysts survive reduced hydration, group 1 late embryogenesis abundant (LEA) proteins, hydrophilic unstructured proteins that accumulate in the stress-tolerant cysts of A. franciscana, were knocked down using RNA interference (RNAi). Embryos lacking group 1 LEA proteins showed significantly lower survival than control embryos after desiccation and freezing, or freezing alone, demonstrating a role for group 1 LEA proteins in A. franciscana tolerance of low water conditions. In contrast, regardless of group 1 LEA protein presence, cysts responded similarly to hydrogen peroxide (H2O2) exposure, indicating little to no function for these proteins in diapause termination. This is the first in vivo study of group 1 LEA proteins in an animal and it contributes to the fundamental understanding of these proteins. Knowing how LEA proteins protect A. franciscana cysts from desiccation and freezing may have applied significance in aquaculture, where Artemia is an important feed source, and in the cryopreservation of cells for therapeutic applications. 相似文献
2.
3.
《Bioscience, biotechnology, and biochemistry》2013,77(12):3014-3018
To clarify the effect of superoxide dismutase (SOD) on the formation of hydroxyl radical in a standard reaction mixture containing 15 μM of xanthone, 0.1 M of 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and 45 mM of phosphate buffer (pH 7.4) under UVA irradiation, electron paramagnetic resonance (EPR) measurements were performed. SOD enhanced the formation of hydroxyl radicals. The formation of hydroxyl radicals was inhibited on the addition of catalase. The rate of hydroxyl radical formation also slowed down under a reduced oxygen concentration, whereas it was stimulated by disodium ethylenediaminetetraacetate (EDTA) and diethyleneaminepentaacetic acid (DETAPAC). Above findings suggest that O2, H2O2, and iron ions participate in the reaction. SOD possibly enhances the formation of the hydroxyl radical in reaction mixtures of photosensitizers that can produce O2 ?·. 相似文献
4.
《Harmful algae》2013
The dinoflagellate Lingulodinium polyedrum is a toxin producer that shows the ability of turning to resting cysts as a survival strategy when exposed to environmental unfavorable conditions, such as nitrogen and phosphorus depletion, abrupt changes in temperature or light, and chemical or mechanical stress. Algal adaptation to all these conditions involves hydrogen peroxide (H2O2) and nitric oxide (NO) as key redox signals for housekeeping cellular processes. Thus, we aim here to shed light on the role of H2O2 and NO (from aqueous decomposition of sodium nitroprusside, SNP) as prooxidant agents and putative redox signals for encystment of the dinoflagellate L. polyedrum. Harsh oxidative stress imposed by 500 μM H2O2 treatment forced L. polyedrum cells to rapidly encyst, in less than 30 min, whereas slower cyst formation was observed upon lower H2O2 doses. L. polyedrum encystment was marked by a significant increase in the antioxidant carotenoid peridinin, although other photosynthetic pigments (chlorophyll a and β-carotene) and light-harvesting complexes (peridinin complex protein, PCP) were all diminished in cyst forms. Although SOD activity (a frontline antioxidant enzyme) was severely inhibited by increasing doses of H2O2, a theoretical compensatory effect was provided by the dose-dependent increase of ascorbate peroxidase activity (APX), which resulted in significant lower levels of lipid peroxidation during cyst formation. Although SNP data cannot be fully compared to those found with H2O2 treatments, changes in APX activity and in biomarkers of lipid and protein oxidation matched the dose–responses found in H2O2 experiments, revealing similar biochemical and morphological responses against increasing oxidative conditions during cyst formation. Our data significantly contribute to a better understanding of the relationship between encystment, photosynthesis, and antioxidant responses triggered by H2O2 and NO in L. polyedrum, a harmful diarrhetic shellfish poisoning toxin (DSPs) producer. 相似文献
5.
When diapause and non‐diapause eggs of the same bivoltine strain of Bombyx mori were chilled at 5°C for more than 30 days, the hatchability of diapause eggs increased while that of non‐diapause eggs decreased, respectively. To investigate the relationship between effects of chilling on the hatchability and the metabolism of hydrogen peroxide (H2O2), content of H2O2 and activities of superoxide dismutase (SOD), xanthine oxidase (XO), and catalase (CAT) between diapause and non‐diapause eggs were determined during the chilling at 5°C. The significant enhancement of H2O2 occurred prior to the quick increase of the hatchability in diapause eggs and coincided with the quick decline of the hatchability in non‐diapause eggs, respectively. Diapause eggs contained significantly higher H2O2 and XO activity and lower CAT activity compared to non‐diapause eggs. Our results showed that there were significant differences in the metabolism of H2O2 between diapause and non‐diapause eggs during chilling and that significant enhancement of H2O2 may be involved in the diapause termination of diapause eggs and the cell damage of non‐diapause eggs. © 2010 Wiley Periodicals, Inc. 相似文献
6.
Generation of hydroxyl radicals by soybean nodule leghaemoglobin 总被引:4,自引:0,他引:4
Leghaemoglobin, a protein present in root nodules of soybean (Glycine max (L.) Merr.), generates the highly reactive hydroxyl radical (·OH) upon incubation with hydrogen peroxide (H2O2). The H2O2 appears to cause breakdown of the haem, releasing iron ions that convert H2O2 into ·OH outside the protein. Oxyleghaemoglobin (oxygenated ferrous protein) is more sensitive to attack by H2O2 than is metleghaemoglobin (ferric protein). The possibility of oxyleghaemoglobin breakdown by H2O2 and formation of damaging ·OH may explain why the root nodule is equipped with iron-storage proteins and enzymes that can remove H2O2. 相似文献
7.
Artemia franciscana embryos enter diapause as encysted gastrulae, a physiological state of metabolic dormancy and enhanced stress resistance. The objective of this study was to use RNAi to investigate the function of p26, an abundant, diapause-specific small heat shock protein, in the development and behavior of encysted Artemia embryos (cysts). RNAi methodology was developed where injection of Artemia females with dsRNA specifically eliminated p26 from cysts. p26 mRNA and protein knock down were, respectively, confirmed by RT-PCR and immuno-probing of western blots. ArHsp21 and ArHsp22, diapause-related small heat shock proteins in Artemia cysts sharing a conserved α-crystallin domain with p26, were unaffected by injection of females with dsRNA for p26, demonstrating the specificity of protein knock down. Elimination of p26 delayed cyst release from females demonstrating that this molecular chaperone influences the development of diapause-destined embryos. Although development was slowed the metabolic activities of cysts either containing or lacking p26 were similar. p26 inhibited diapause termination after prolonged incubation of cysts in sea water perhaps by a direct effect on termination or indirectly because p26 is necessary for the preservation of diapause maintenance. Cyst diapause was however, terminated by desiccation and freezing, a procedure leading to high mortality within cyst populations lacking p26 and indicating the protein is required for stress tolerance. Cysts lacking p26 were also less resistant to heat shock. This is the first in vivo study to show that knock down of a small heat shock protein slows the development of diapause-destined embryos, suggesting a role for p26 in the developmental process. The same small heat shock protein prevents spontaneous termination of diapause and provides stress protection to encysted embryos. 相似文献
8.
Irena Kruk Teresa Michalska Aleksandra Kładna Hassan Y. Aboul‐Enein 《Luminescence》2011,26(6):429-433
Carazolol [4‐(2‐hydroxy‐3‐isopropyl‐amino‐propoxy)‐carbazole], a β3‐adrenoceptor agonist, is clinically used in the treatment of hypertension, cardiac arrhythmias and angina pectoris. Despite the beneficial effect of the drug, its high dose may contribute to cardiotoxicity. This study was conducted to examine whether carazolol can influence hydroxyl radical formation by a Fenton‐like reaction [Co(II) + H2O2 + HO‐] in the presence of ethylenediaminetetraacetic acid. The oxygen free radicals and singlet oxygen (1O2) formation was traced by three different assay methods: chemiluminescence (CL), an electron spin resonance (ESR) spin trapping with 2,2,6,6‐tetramethyl‐4‐piperidine and 5,5‐dimethyl‐1‐pyrroline‐1‐oxide, and spectrophotometric determination of 1O2 based on bleaching of p‐nitrosodimethylaniline. The effect of hydroxyl radical inhibitors and 1O2 quenchers on peroxidation of carazolol was also examined. The results indicated that carazolol enhanced the HO radical and 1O2 formation in a Fenton‐like reaction. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
9.
《Bioscience, biotechnology, and biochemistry》2013,77(6):1324-1331
Phosvitin, a phosphoprotein known as an iron-carrier in egg yolk, binds almost all the yolk iron. In this study, we investigated the effect of phosvitin on Fe(II)-catalyzed hydroxyl radical (?OH) formation from H2O2 in the Fenton reaction system. Using electron spin resonance (ESR) with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and deoxyribose degradation assays, we observed by both assays that phosvitin more effectively inhibited ?OH formation than iron-binding proteins such as ferritin and transferrin. The effectiveness of phosvitin was related to the iron concentration, indicating that phosvitin acts as an antioxidant by chelating iron ions. Phosvitin accelerates Fe(II) autoxidation and thus decreases the availability of Fe(II) for participation in the ?OH-generating Fenton reaction. Furthermore, using the plasmid DNA strand breakage assay, phosvitin protected DNA against oxidative damage induced by Fe(II) and H2O2. These results provide insight into the mechanism of protection of the developing embryo against iron-dependent oxidative damage in ovo. 相似文献
10.
The recent spread of <Emphasis Type="Italic">Artemia parthenogenetica</Emphasis> in Western Australia 总被引:1,自引:1,他引:0
Kellie McMaster Alan Savage Terrie Finston Michael S. Johnson Brenton Knott 《Hydrobiologia》2007,576(1):39-48
In Western Australia, populations of Artemia parthenogenetica in coastal salt lakes at Rottnest Island and Lake Hayward, and in salterns at Port Hedland and Shark Bay, are widely accepted
to have been introduced by humans. Further, within the past 10 years, populations of A. parthenogenetica have been found in inland playa salt lakes in the wheatbelt of south-west Western Australia, where none had been recorded
in previous salt lake studies. Here we hypothesise that birds act as transport vectors for Artemia cysts both within Australia and between the Asian and Australian continents. Allozyme analysis was used to identify clonal
types (multi-locus genotypes), clonal frequencies, genotypic diversities and genotypic identity of six populations (three
coastal, three inland).
Overall, the inland populations displayed almost identical genotypic structure to the coastal population from Lake Hayward,
indicating that Lake Hayward could be the major source for dispersal and colonisation of inland populations. Results support
the hypothesis of dispersal inland by nomadic bird species. Furthermore, evidence suggests that the inland and Lake Hayward
populations may be an example of a metapopulation.
The greater variety of genotypes present in the Rottnest population indicates that this population has received a large number
of small immigrations, or that it received one large introduction. The former may indicate a long period of suitable salinities,
providing a greater time-span over which migration and succession of clonal types could occur in comparison to other populations.
While we cannot rule out the possibility of human introduction of A. parthenogenetica to Rottnest, the hypothesis of cyst dispersal along the Austral-Asian flyway remains possible.
Guest Editor: John M. Melack
Saline Waters and their Biota 相似文献
11.
MacRae TH 《Seminars in cell & developmental biology》2003,14(5):251-258
Embryos of the brine shrimp, Artemia franciscana, either develop directly into swimming larvae or are released from females as encysted gastrulae (cysts) which enter diapause, a reversible state of dormancy. Metabolic activity in diapause cysts is very low and these embryos are remarkably resistant to physiological stresses. Encysting embryos, but not those undergoing uninterrupted development, synthesize large amounts of two proteins, namely p26 and artemin. Cloning and sequencing demonstrated p26 is a small heat shock/alpha-crystallin protein while artemin has structural similarity to ferritin. p26 exhibits molecular chaperone activity in vitro, moves reversibly into nuclei during stress and confers thermotolerance on transformed organisms, suggesting critical roles in cyst development. The function of artemin is unknown. Encysted Artemia also contain an abundance of trehalose, a disaccharide capable of protecting embryos. Artemia represent a novel experimental system where the developmental functions of small heat shock/alpha-crystallin proteins and other stress response elements can be explored. 相似文献
12.
An ultraviolet (UV)-based advanced oxidation process (AOP), with hydrogen peroxide and medium-pressure (MP) UV light (H2O2/UV), was used as a pretreatment strategy for biofilm control in water. Suspended Pseudomonas aeruginosa cells were exposed to UV-based AOP treatment, and the adherent biofilm formed by the surviving cells was monitored. Control experiments using H2O2 or MP UV irradiation alone could inhibit biofilm formation for only short periods of time (<24 h) post-treatment. In a H2O2/filtered-UV (>295 nm) system, an additive effect on biofilm control was shown vs filtered-UV irradiation alone, probably due to activity of the added hydroxyl radical (OH?). In a H2O2/full-UV (ie full UV spectrum, not filtered) system, this result was not obtained, possibly due to the germicidal UV photons overwhelming the AOP system. Generally, however, H2O2/UV prevented biofilm formation for longer periods (days) only when maintained with residual H2O2. The ratio of surviving bacterial concentration post-treatment to residual H2O2 concentration played an important role in biofilm prevention and bacterial regrowth. H2O2 treatments alone resulted in poorer biofilm control compared to UV-based AOP treatments maintained with similar levels of residual H2O2, indicating a possible advantage of AOP. 相似文献
13.
Summary Effects of nonchelating and chelating agents at 10 mM on the serum-free culture of rat dermal fibroblasts were investigated. A strong iron-chelating agent, iminodiacetic acid
(IDA), and a weak one, dihydroxyethylglycine (DHEG), decreased iron permeation into preconfluent fibroblasts. A weak iron-chelating
agent, glycylglycine (GG), a nonchelating agent, N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES), and human apotransferrin (10 μg/ml) increased the permeation with time. Iron may be essential
for survival of fibroblasts because subconfluent fibroblasts exposed to 100 μM FeSO4 in combination with transferrin, HEPES, or GG significantly decreased to release lactate dehydrogenase into the medium. Superoxide
dismutase and dimethyl sulfoxide blocked the enzyme release, suggesting that superoxide and hydroxyl radical induce cellular
damage but hydrogen peroxide (H2O2) generated by superoxide dismutation does not. GG significantly reduced H2O2 cytotoxicity. DHEG acted as a potent promoter of the iron-stimulated cellular damage if ascorbate or H2O2 was added to the medium. FeSO4 and FeCl3 (50 to 100 μM) individually combined with IDA maximally promoted fibroblast proliferation. Ascorbate increased formation of thiobarbituric
acid-reactive substances from deoxyribose in the medium supplemented with FeSO4 and either IDA or DHEG. Conversely, ascorbate decreased the formation in the medium with FeSO4 and with or without other agents. Fibroblast proliferation may thus be stimulated through the active oxygen generation mediated
by a redox-cycling between Fe3+ and Fe2+, which are dissolved in the medium at a high concentration, rather than through delivery of iron into the cells. 相似文献
14.
Endogenous Superoxide Dismutase Levels Regulate Iron-Dependent Hydroxyl Radical Formation in Escherichia coli Exposed to Hydrogen Peroxide
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Michael L. McCormick Garry R. Buettner Bradley E. Britigan 《Journal of bacteriology》1998,180(3):622-625
Aerobic organisms contain antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, to protect them from both direct and indirect effects of reactive oxygen species, such as O2·− and H2O2. Previous work by others has shown that Escherichia coli mutants lacking SOD not only are more susceptible to DNA damage and killing by H2O2 but also contain larger pools of intracellular free iron. The present study investigated if SOD-deficient E. coli cells are exposed to increased levels of hydroxyl radical (·OH) as a consequence of the reaction of H2O2 with this increased iron pool. When the parental E. coli strain AB1157 was exposed to H2O2 in the presence of an α-(4-pyridyl-1-oxide)-N-tert-butyl-nitrone (4-POBN)–ethanol spin-trapping system, the 4-POBN–·CH(CH3)OH spin adduct was detectable by electron paramagnetic resonance (EPR) spectroscopy, indicating ·OH production. When the isogenic E. coli mutant JI132, lacking both Fe- and Mn-containing SODs, was exposed to H2O2 in a similar manner, the magnitude of ·OH spin trapped was significantly greater than with the control strain. Preincubation of the bacteria with the iron chelator deferoxamine markedly inhibited the magnitude of ·OH spin trapped. Exogenous SOD failed to inhibit ·OH formation, indicating the need for intracellular SOD. Redox-active iron, defined as EPR-detectable ascorbyl radical, was greater in the SOD-deficient strain than in the control strain. These studies (i) extend recent data from others demonstrating increased levels of iron in E. coli SOD mutants and (ii) support the hypothesis that a resulting increase in ·OH formation generated by Fenton chemistry is responsible for the observed enhancement of DNA damage and the increased susceptibility to H2O2-mediated killing seen in these mutants lacking SOD. 相似文献
15.
Qiang Dong Kai Yang Stephanie M. Wong Peter J. O’Brien 《Chemico-biological interactions》2010,188(1):31-37
Excessive sugar intake in animal models may cause tissue damage associated with oxidative and carbonyl stress cytotoxicity as well as inflammation. Fructose became a 100-fold more cytotoxic if hepatocytes were exposed to a non-toxic infusion of H2O2 so as to simulate H2O2 released by Kupffer cells or infiltrating immune cells. In order to determine the molecular mechanisms involved, protein carbonylation of fructose and its metabolites were determined using the 2,4-dinitrophenylhydrazine method. In a cell-free system, fructose was found to carbonylate bovine serum albumin (BSA) only if low concentrations of FeII/H2O2 were added. Protein carbonylation by the fructose metabolites glyceraldehyde or glycolaldehyde was also markedly increased by FeII/H2O2. The protein carbonylation may be attributed to glyoxal formation by hydroxyl radicals as the glyoxal trapping agent aminoguanidine or hydroxyl radical scavengers prevented protein carbonylation. Glyoxal was also much more effective than other carbonyls at causing protein carbonylation. When BSA was replaced by isolated rat hepatocytes, fructose metabolite glyceraldehyde in the presence of non-toxic 2 μM FeII:8-hydroxyquinoline (HQ) and a H2O2 generating system (glucose/glucose oxidase) markedly increased cytotoxicity, protein carbonylation and reactive oxygen species (ROS)/H2O2 formation. Furthermore this was prevented by hydroxyl radical scavengers or aminoguanidine, a glyoxal scavenger. CuII: 8-hydroxyquinoline increased H2O2 induced hepatocyte protein carbonylation less but was prevented by aminoguanidine. However, cytotoxicity and protein carbonylation induced by glyceraldehyde/CuII:HQ/H2O2 were not affected by hydroxyl radical scavengers. Although fatty liver induced by an excessive sugar diet in animal models has been proposed as the first hit for non-alcoholic steatohepatitis (NASH) we propose that oxidative stress induced by the oxidation of fructose or fructose metabolites catalysed by Fenton FeII/H2O2 could be a ‘second hit’. A perpetual cycle of oxidative stress in hepatocytes could lead to cytotoxicity and contribute to NASH development. 相似文献
16.
The 24 h effect of low (20°C) and high (43°C) temperature on the antioxidant enzyme activities and lipid peroxidation was
investigated in intact cells of the cyanobacteriumSynechocystis PCC 6803 grown at 36°C. At low temperature treated cells, the superoxide dismutase, catalase and glutathione peroxidase activities
were significantly higher and the protein content lower than in high temperature treated cells. The increase of hydroxyl free
radical level and malonyldialdehyde formation, when algal cells were exposed to low temperature, were due to the stimulated
production of superoxide radicals O2
− and hydrogen peroxide (H2O2). 相似文献
17.
O. Cantoni G. Brandi G.F. Schiavano A. Albano F. Cattabeni 《Chemico-biological interactions》1989,70(3-4)
The toxicity of H2O2 in Escherichia coli wild type and superoxide dismutase mutants was investigated under different experimental conditions. Cells were either grown aerobically, and then treated in M9 salts or K medium, or grown anoxically, and then treated in K medium. Results have demonstrated that the wild type and superoxide dismutase mutants display a markedly different sensitivity to both modes of lethality produced by H2O2 (i.e. mode one killing, which is produced by concentrations of H2O2 lower than 5 mM, and mode two killing which results from the insult generated by concentrations of H2O2 higher than 10 mM). Although the data obtained do not clarify the molecular basis of H2O2 toxicity and/or do not explain the specific function of superoxide ions in H2O2-induced bacterial inactivation, they certainly demonstrate that the latter species plays a key role in both modes of H2O2 lethality. A mechanism of H2O2 toxicity in E. coli is proposed, involving the action of a hypothetical enzyme which should work as an O2-• generating system. This enzyme should be active at low concentrations of H2O2 (<5 mM) and high concentrations of the oxidant (>5 mM) should inactivate the same enzyme. Superoxide ions would then be produced and result in mode one lethality. The resistance at intermediate H2O2 concentrations may be dependent on the inactivation of such enzyme with no superoxide ions being produced at levels of H2O2 in the range 5–10 mM. Mode two killing could be produced by the hydroxyl radical in concert with superoxide ions, chemically produced via the reaction of high concentrations of H2O2 (>10 mM) with hydroxyl radicals. The rate of hydroxyl radical production may be increased by the higher availability of Fe2+ since superoxide ions may also reduce trivalent iron to the divalent form. 相似文献
18.
The concentration of total ninhydrin-positive material (NPM) soluble in 5% trichloroacetic acid was measured in cysts of the brine shrimp, Artemia salina, as a function of hydration level. No net change in NPM was observed until the cysts had achieved a water content of about 0.65 g H2O/g of initially dry cysts. Above this hydration threshold the NPM content increased markedly. Examination of the free amino acid composition of cysts incubated at selected hydration levels revealed that almost all of the amino acids underwent net change above the hydration threshold. However, just below this threshold, the free amino acid composition was essentially the same as in fully dried cysts. The activity generating net changes in the concentration of free amino acids above the hydration threshold was shown to be metabolic in nature and restricted to the cellular component of the cyst. 相似文献
19.
Enriched peribacteroid membranes were prepared from Phaseolus vulgaris nodules and, in the presence of metleghemoglobin and H2O2, membranal lipid peroxidation was observed. The initial rate of the reaction was low and increased with time. Ferrous leghemoglobin was unable to induce this peroxidation with H2O2. Thus, it appears that leghemoglobin (IV) is not the activated species involved in this process. Heme plays a role in this peroxidation and the hydroxyl radical is not an intermediate of the reaction. Lipid peroxidation in peribacteroid membranes was also observed in the presence of iron ions. A mixture of iron (III) and iron (II) produced a maximal peroxidation. Senescing nodule extracts were able to provoke membranal lipid peroxidation; they contained nonprotein-bound iron. Peribacteroid membranes were more sensitive than microsomes to peroxidation, as measured by malonaldehyde formation. 相似文献
20.
Yusuke Katsuda Yoshimi Niwano Takuji Nakashima Takayuki Mokudai Keisuke Nakamura Satomi Oizumi Taro Kanno Hiroyasu Kanetaka Hiroshi Egusa 《PloS one》2015,10(8)
Cytoprotective effects of short-term treatment with grape seed extract (GSE) upon human gingival fibroblasts (hGFs) were evaluated in relation to its antioxidant properties and compared with those of a water-soluble analog of vitamin E: trolox (Tx). GSE and Tx showed comparable antioxidant potential in vitro against di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH; a stable radical), hydroxyl radical (•OH), singlet oxygen (1O2), and hydrogen peroxide (H2O2). Pretreatment or concomitant treatment with GSE for 1 min protected hGFs from oxidative stressors, including H2O2, acid-electrolyzed water (AEW), and 1O2, and attenuated the intracellular formation of reactive oxygen species induced by H2O2 and AEW. Tx also reduced the H2O2- and AEW-induced intracellular formation of reactive oxygen species, but showed no cytoprotective effects on hGFs exposed to H2O2, AEW, or 1O2. These results suggest that the cytoprotective effects of GSE are likely exerted independently of its antioxidant potential. 相似文献