共查询到20条相似文献,搜索用时 15 毫秒
1.
Pepticare, a herbomineral formulation of the Ayurveda medicine consisting of the herbal drugs: Glycyrrhiza glabra, Emblica officinalis and Tinospora cordifolia, was tested for its anti-ulcer and anti-oxidant activity in rats. Effects of various doses (125, 250, 500 and 1000 mg/kg, p.o.) of Pepticare were studied on gastric secretion and gastric ulcers in pylorus-ligation and on ethanol-induced gastric mucosal injury in rats. The reduction in ulcer index in both the models along with the reduction in volume and total acidity, and an increase in the pH of gastric fluid in pylorus-ligated rats proved the anti-ulcer activity of Pepticare. It was also found that Pepticare was more potent than G. glabra alone in protecting against pylorus-ligation and ethanol-induced ulcers. The increase in the levels of superoxide dismutase, catalase, reduced glutathione and membrane bound enzymes like Ca 2+ATPase, Mg 2+ATPase and Na +K +ATPase and decrease in lipid peroxidation in both the models proved the anti-oxidant activity of the formulation. Thus it can be concluded that Pepticare possesses anti-ulcer activity, which can be attributed to its anti-oxidant mechanism of action. 相似文献
2.
The effect of calcium (Ca 2+) on Trifolium repens L. seedlings subjected to cadmium (Cd 2+) stress was studied by investigating plant growth and changes in activity of antioxidative enzymes. Physiological analysis
was carried out on seedlings cultured for 2 weeks on half-strength Hoagland medium with Cd 2+ concentrations of 0, 400 and 600 μM, and on corresponding medium supplied with CaCl 2 (5 mM). Exposure to increasing Cd 2+ reduced the fresh weight of the upper part (stems + leaves) of the seedlings more strongly than that of the root system.
In both parts of T. repens seedlings H 2O 2 level and lipid peroxidation increased. In the upper part, Cd 2+ exposure led to a significant decrease in the activity of superoxide dismutase, catalase and glutathione peroxidase and an
increase in ascorbate peroxidase activity. In contrast, the roots showed an increase in the activity of antioxidative enzymes
under Cd 2+ stress. Ca 2+ addition to medium reduced the Cd 2+ accumulation, and considerably reversed the Cd 2+-induced decrease in fresh mass as well as the changes in lipid peroxidation in the both parts of T. repens seedlings. Ca 2+ application diminished the Cd 2+ effect on the activity of antioxidative enzymes in the upper part, even though it did not significantly affect these enzymes
in the roots. So the possible mechanisms for the action of Ca 2+ in Cd 2+ stress were considered to reduce Cd 2+ accumulation, alleviate lipid peroxidation and promote activity of antioxidative enzymes. 相似文献
3.
The isolation and characterization of mutant alleles in a regulatory gene affecting NADP +-dependent enzymes are described. The locus, mex, is at position 26.5 ± 0.74 on the X chromosome of Drosophila melanogaster. The newly isolated mutant allele, mex
1, is recessive to either the mex allele found in Oregon-R wild-type individuals or that found in the cm v parental stock in which the new mutants were induced. The mex
1 mutant allele is associated with statistically significant decreases in malic enzyme (ME) specific activity and ME specific
immunologically cross-reacting material (ME-CRM) in newly emerged adult males. During this same developmental stage in males,
the NADP +-dependent isocitrate dehydrogenase specific activity increases to statistically significant levels. Females of the mex
1 mutant strain show statistically significant elevated levels of the pentose phosphate shunt enzymes, glucose-6-phosphate
dehydrogenase and 6-phosphogluconate dehydrogenase. Isoelectric focusing and thermolability comparisons of the active ME from
mutant and control organisms indicate that the enzyme is the same. Developmental profiles of mex
1 and control strains indicate that this mutant allele differentially modulates the levels of ME enzymatic activity and ME-CRM
during development.
This work was supported by an Operating Grant from the Natural Sciences and Engineering Research Council of Canada to M.M.B. 相似文献
4.
Spectroscopically, the modification of horse heart ferricytochrome c with N-chloro-4-toluolsul-fonamide (Chloramine-T, CT) occurs through a two-step process, the disruption of the methionine-80 sulfur-iron linkage and a reagent-independent change, an intramolecular rearrangement. Chromatographic purification of the preparation at a 2.5:1 reagent-to-protein ratio, pH 8.0–8.5, yields two major products, the F II and F III CT-cytochromes c. Both products contain modification of only the methionines, 80 and 65, to sulfoxides; both are monomeric, reduced by ascorbate, and the ferrous forms are oxidized by molecular oxygen and bind carbon monoxide. The redox potentials of F II and F III are 135 and 175±15 mV. The F III is indistinguishable from the native protein in its binding and the electron donor property toward mammalian cytochrome c oxidase. It also binds nearly as effectively as the native protein to yeast cytochrome c peroxidase, but is a less efficient donor. It is, however, a poor electron acceptor from both mammalian cytochrome c reductase and chicken liver sulfite oxidase. F II lacks cytochrome c oxidase activity and is also a poorer substrate for the other three enzymes. Both the derivatives are consistently better electron donors than acceptors. It is concluded that the binding of cytochrome c to cytochrome c oxidase and to cytochrome c peroxidase does not require the integrity of the methionine-80 sulfur linkage and that the complexation process has a finite degree of freedom with regard to the state of the heme crevice opening. The alterations of the oxidoreduction function have been analyzed in light of both prevailing models of cytochrome c function, the two-site model (one site for oxidizing and the other for reducing enzymes) and the single-site model (the same site for the oxidizing and reducing enzymes). These observations can be accommodated by either model, given the latitude that the binding domains for the oxidizing and the reducing enzymes have finite overlapping and nonoverlapping regions.To whom all correspondence related to the functional studies with cytochrome c peroxidase and sulfite oxidase is to be directed. 相似文献
5.
The present study was aimed to evaluate the therapeutic effects of Withania somnifera along with paclitaxel on lung tumor induced by benzo(a)pyrene in male Swiss albino mice. The levels of ATPase enzymes and lipid peroxidation were evaluated in lung cancer bearing mice, in erythrocyte membrane and tissues. The extent of peroxidation was estimated by measuring the thiobarbituric acid-reactive substances. Simultaneously the activities of different ATPases (Na +/K +-ATPases, Mg 2+-ATPases and Ca 2+-ATPases) were determined. The alterations of these enzyme activities in membrane and tissues were indicative of the tumor formation caused by benzo(a)pyrene (50 mg/kg body weight, orally) in cancer bearing animals. The activities of these enzymes were reversed to near normal control values in animals treated with Withania somnifera (400 mg/kg b.wt, orally) along with paclitaxel (33 mg/kg b.wt, i.p). Treatment with Withania somnifera along with paclitaxel altered these damage mediated through free radicals, and the treatment displays the protective role of these drugs by inhibiting free radical mediated cellular damages. Over, based on the data providing a correlation Withania somnifera along with paclitaxel provide stabilization of membrane bound enzyme profiles and decreased lipid peroxidation against benzo(a)pyrene induced lung cancer in mice. 相似文献
6.
High concentration of L-cystine (0.25%) when present in a glucose-mineral salt medium inhibited sporulation-specific events
like protease production, calcium uptake and dipicolinic acid synthesis in Bacillus thuringiensis var. thuringiensis. In addition, the enzymes of the Krebs cycle from aconitase onwards were completely inhibited by a high concentration of cystine.
At a low concentration of cystine (0.05%), none of the above mentioned macromolecular changes were affected. Lipid synthesis
monitored by [1,2 14 C]-acetate incorporation into lipid as well as into whole cells was completely inhibited. 相似文献
7.
The polar lipid fatty acids, lipopolysaccharide hydroxy-fatty acids, and respiratory quinones of Geobacter metallireducens str. GS-15, Geobacter sulfurreducens str. PCA, and Geobacter bemidjiensis str. Bem are reported. Also, the lipids of G. metallireducens were compared when grown with Fe 3+ or nitrate as electron acceptors and G. sulfurreducens with Fe 3+ or fumarate. In all experiments, the most abundant polar lipid fatty acids were 14:0, i15:0, 16:1ω7c, 16:1ω5c, and 16:0;
lipopolysaccharide hydroxy-fatty acids were dominated by 3oh16:0, 3oh14:0, 9oh16:0, and 10oh16:0; and menaquinone-8 was the
most abundant respiratory quinone. Some variation in lipid profiles with strain were observed, but not with electron acceptor.
D. C. White: Deceased. 相似文献
8.
Gram-positive bacteria of the genus Rhodococcus catabolize p-hydroxybenzoate (PHB) through the initial formation of 3,4-dihydroxybenzoate. High levels of p-hydroxybenzoate hydroxylase (PHBH) activity are induced in six different Rhodococcus species when these strains are grown on PHB as sole carbon source. The PHBH enzymes were purified to apparent homogeneity and appeared to be homodimers of about 95 kD with each subunit containing a relatively weakly bound FAD. In contrast to their counterparts from gram-negative microorganisms, the Rhodococcus PHBH enzymes prefer NADH to NADPH as external electron donor. All purified enzymes were inhibited by Cl – and for five of six enzymes more pronounced substrate inhibition was observed in the presence of chloride ions. 相似文献
9.
Biomass and lipid productivities of Chlorella vulgaris under different growth conditions were investigated. While autotrophic growth did provide higher cellular lipid content (38%),
the lipid productivity was much lower compared with those from heterotrophic growth with acetate, glucose, or glycerol. Optimal
cell growth (2 g l −1) and lipid productivity (54 mg l −1 day −1) were attained using glucose at 1% (w/v) whereas higher concentrations were inhibitory. Growth of C. vulgaris on glycerol had a similar dose effects as those from glucose. Overall, C. vulgaris is mixotrophic. 相似文献
10.
采用盆栽试验方法,分别设置0(对照,不添加镉)、30、60、90、120、150、180、210mg·kg-1共8个土壤镉处理水平,研究土壤不同镉水平对马缨丹(Lantana comara L.)生长及其抗氧化酶活性的影响,以探讨马缨丹对镉胁迫的生理响应机制。结果显示:(1)随着土壤镉处理浓度的升高,马缨丹干重呈先升高后降低的趋势,30mg·kg-1镉处理能促进植株的生长,而浓度高于60mg·kg-1时显著抑制马缨丹的生长。(2)马缨丹叶片和根系中O-·2产生速率、H2O2和MDA含量及电解质渗漏率均随土壤镉处理浓度的升高和胁迫时间的延长逐渐升高,胁迫90d时,叶片和根系中O-·2产生速率、H2O2和MDA含量及电解质渗漏率分别在镉浓度高于60和30mg·kg-1时显著低于对照。(3)叶片和根系抗氧化酶SOD、POD、APX和CAT活性随着土壤镉处理浓度的增加大体呈先升高后降低的趋势,并在镉浓度分别高于90和60mg·kg-1时,叶片和根系抗氧化酶活性显著低于对照。研究表明,低浓度镉处理土壤能促进马缨丹植株生长,而高浓度镉处理土壤显著降低了马缨丹体内抗氧化酶活性,导致活性氧大量积累,引起严重的膜脂过氧化伤害,从而显著抑制马缨丹植株的生长。 相似文献
11.
The potential of plant nutrients (such as sulphur, S) and phytohormones (such as salicylic acid, SA) has been explored in isolated studies by researchers in controlling the impact of abiotic stresses such as salinity in plants. However, information is scanty on the major mechanisms underlying the role of S and/or SA in modulation of enzymes involved in nitrogen (N) assimilation, GOGAT cycle, and antioxidant defence system; the cellular status of N-containing osmolyte proline, glucose, S-containing compounds; and their cumulative role in photosynthesis functions and growth in crop plants. The present study aimed to assess the role of cumulative effect of SA and S (SO42−) mediated induction of N assimilatory enzymes, GOGAT cycle, N-osmolyte proline and its metabolizing enzymes, glyoxylase enzymes, and antioxidant capacity in mungbean (Vigna radiata L.) exposed to NaCl with or without SO42− and SA. Salt-exposed V. radiate showed differential elevations in damage (O.2−, H2O2, lipid peroxidation; glucose) and defence (ascorbate peroxidase, APX; glutathione reductase, GR; superoxide dismutase, SOD; reduced GSH; proline) and inhibitions in the activities of NR and NiR; N content, photosynthesis, photosynthetic N-use-efficiency (NUE), and growth. The separate supplementation of SA and SO42− to 50 mM NaCl almost equally strengthened the antioxidant machinery and diminished NaCl-accrued damages. However, combined supply of SA and SO42− to NaCl-exposed cultivars led to significant improvements in NR and NiR activities, the accumulation of N, GSH, proline, enhanced activity of APX, GR, and reduced activity of SOD, and also decreases in O.2−, H2O2, lipid peroxidation and glucose. These observations were corroborated with SA, SO42− and NaCl-mediated changes in the traits of photosynthesis and growth, stomatal behaviour, and the polypeptide patterns of Rubisco in V. radiata. Overall, in V. radiata, SA-mediated higher enhancements in the activity of N assimilatory enzymes (NR, NiR, and GS), increase in the N and proline, and GSH; and decreases in the contents of Na+ and Cl− ions, and glucose (a photosynthesis repressor); maintenance of a fine tuning among SOD, APX, and GR enzymes; and higher minimization of ROS (O.2−, H2O2) and lipid peroxidation finally led to a higher promotion in photosynthesis and growth. 相似文献
12.
Here we present studies on the antioxidant status of a semi-natural grassland community, permanently growing in mini-FACE rings under elevated concentrations of atmospheric CO 2 (560 μmol mol −1). In general, in leaves of Dactylis glomerata L. and Trifolium repens L., no differences between ambient and elevated CO 2 were detected as concerns protein content, activity of oxidant-scavenging enzymes (catalase, superoxide dismutase, ascorbate peroxidase and guaiacol peroxidase), and lipid peroxidation. The activity of antioxidant-regenerating enzymes (monodehydroascorbate reductase, dehydroascorbate reductase and glutathione disulfide reductase) and the content of antioxidants (ascorbic acid, dehydroascorbic acid, reduced glutathione and glutathione disulfide) showed remarkable variability between leaves from plants grown in ambient and CO 2-enriched mini-FACE rings. Thus, in general it can be concluded that the effects of elevated CO 2 at environmentally relevant concentrations on the leaf antioxidant status of a grassland community are extremely variable, species-specific and rather limited. 相似文献
13.
Two ornithine carbamoyltransferases (OCT 1 and OCT 2) were isolated from Pseudomonas syringae pv. phaseolicola and purified by precipitation with ammonium sulfate, heat denaturation, chromatography on DEAE-Sephadex A-50 and Sephadex G-200. Molecular weights of both enzymes: 110,000; optimal activity: pH 8.5 to 9.5 (OCT 1), pH 8.4 (OCT 2); apparent K
m for ornithine: 7·10 -4 (both enzymes); apparent K
m for carbamoylphosphate: 7·10 -4 (OCT 1), 2.8·10 -3 (OCT 2). Both enzymes possess only an anabolic function. OCT 1 is highly inhibited by low concentrations of phaseolotoxin and Orn-P(O)(NH 2)-NH-SO 3H, OCT 2 is insensitive to both compounds. The inhibition of OCT 1 is reversible.Non-common abbreviation PNSOrn
Ornithine--P(O)(NH 2)-NH-SO 3H 相似文献
14.
Asparagine was found to be the main N compound exported from Discaria trinervis nodules. Aspartate (Asp), glutamate (Glu), alanine (Ala) and serine (Ser) were also detected in root xylem sap, but at lower concentrations. A comparable picture is found in nodulated alfalfa. We hypothesized that a similar set of enzymes for Asn synthesis was present in D. trinervis nodules. We demonstrate the expression of most of the enzymes involved in the synthesis of Asn from NH +
4 and oxoacids, in nodules – but not in roots – of fully symbiotic D. trinervis. By complementation of enzyme assays ( A) and immunodetection ( I) we detected glutamane-synthetase (GS A, I), Asp-aminotransferase (AAT A), malate-dehydrogenase (MDH A, I, at least two isoforms), Glu-dehydrogenase (GDH A), Glu-synthase (GOGAT I) and Asn-synthetase (AS I). PEP-carboxylase (PEPC) activity was not detected. We previously shown that N acts as a negative regulator of nodulation and nodule growth, while P is a strong stimulator for nodule growth. We present data on the regulation of nodule N metabolism by altering, during 4 weeks, the availability of N, P and light in symbiotic D. trinervis. NH 4NO 3 (2 m M) induced inactivation and degradation of nodule GS, MDH and AS, but activation of GDH and AAT; the amount of nitrogenase components was not affected. A 10-fold increase in P supply did not greatly affect activity and amount of enzymes, suggesting that N metabolism is not P-limited in nodules. On the other hand, suppression of P supply induced an important reduction of nodule GS, GOGAT, MDH and AS protein levels, although nitrogenase was not affected. GDH was the only measured activity that was stimulated by limiting P supply. Shading plants did result in complete degradation of nitrogenase and partial degradation of GS, AS and nodule-specific MDH isoform, but GDH and AAT were activated. These results are discussed in connection with the regulation of nodulation and nodule growth in D. trinervis. 相似文献
15.
Phallolysin, a water soluble protein of M
r
34,000 produced by the poisonous mushroom Amanita phalloides, causes lysis of various mammalian cell types. Lysis is thought to be initiated by the formation of ion permeable membrane channels. We therefore studied the interaction of phallolysin with solvent-free planar lipid bilayers. In the presence of low phallolysin concentrations (10–100 n M) single channel current fluctuations were observed. Unit channel conductances are 44 pS in 500 m M NaCl and 77 pS in 1 M NaCl. Although the channel does not significantly discriminate between alkali cations, its permeability to Cl - is lower ( P
K
+/ P
Cl
-=4/1). Gating kinetics display a pronounced bursting behavior and a dependence on membrane voltage, cis side pH-value, and on membrane lipid composition. An equivalence relation between membrane voltage and proton concentration was found, i.e. a pH change of one unit is equivalent to a corresponding voltage change of 130 mV. Dependence on the amount of negatively charged lipids is explained by changes of the actual pH due to surface charge effects.Abbreviations 1,3-SMPC
1-stearoyl-3-myristoyl-glycero-2-phosphocholine
- 1,2-DOPS
1,2-dioleoyl-glycero-3-phosphoserine 相似文献
16.
Cytophaga johnsonae Stanier strain C21 ( C. johnsonae C21) contains phosphatidylethanolamine (PE), an unusual glycine-containing lipid (glycine lipid), and two kinds of unidentified lipid as major lipid components. One of the latter lipids was identified by chemical and physicochemical methods as iso-3-hydroxy fatty acid, -amide linked to ornithine and esterified to iso-nonhydroxy fatty acid (ornithine lipid). The other lipid was identified as a sulfonolipid by a tracer experiment using 35S. PE, glycine lipid and sulfonolipid were found in all seven species of Cytophage examined, namely, C. huchinsonii, C. heparina, C. johnsonae C21, C. aquatilis, and three unidentified species of Cytophaga. However, ornithine lipid was found only in the latter five species. By contrast, a serine-containing lipid, which is a specific lipid component of Flavobacterium species, was not found in any species of Cytophaga examined. The possible use and significance of amino acid-containing lipids and sulfonolipids as chemosystematic markers of the Cytophaga species are discussed. 相似文献
17.
One- and two-dimensional 1H- and 13C-NMR spectra of lipid extracts from Ulva rigida, Gracilaria longa, Fucus virsoides and Codium tomentosum collected in the northern Adriatic Sea allowed screening of the content of fatty acid chains, carotenoids, free and acylated cholesterol and chlorophylls. The carotenoid-to-polyunsaturated fatty acid molar ratio was taken as a comparison parameter in samples of Ulva rigida collected in different loci and seasons; the value was markedly higher in samples from the Lagoon of Venice than from marine coastal waters. The total cholesterol concentration was evaluated by 1H-NMR spectroscopy and similar values were found for all species. Two-dimensional heterocorrelated NMR spectroscopy was shown to give characteristic fingerprints of the lipid extracts from algal samples as regards the content in chlorophylls, unsaturated fatty acids and carotenoids.author for correspondence 相似文献
18.
A NADP +-specific isocitrate dehydrogenase (EC 1.1.1.42) was isolated and purified over 400-fold from Anacystis nidulans. The enzyme activity responded slowly to rapid changes in ligand (NADP +, isocitrate, Mg 2+-ions) or enzyme concentration as well as to rapid changes in temperature. These are properties characteristic of the hysteretic enzymes. In addition, the enzyme activity was subject to product (-ketoglutarate) inhibition. ATP, ADP and CDP also inhibited the enzyme. Unlike several other cyanobacterial enzymes, the isocitrate dehydrogenase of Anacystis is not under redox control. 相似文献
19.
The thermoacidophilic Archaea Thermoplasma acidophilum (optimal growth at 60 °C and pH 1–2), Picrophilus torridus and Picrophilus oshimae (optimal growth at 60 °C and pH 0.7) were able to utilize starch as sole carbon source. During growth these microorganisms
secreted heat and acid-stable glucoamylases into the culture fluid. Applying SDS gel electrophoresis activity bands were detected
with appearent molecular mass (Mw) of 141.0, 95.0 kDa for T. acidophilum, 133.0, 90.0 kDa for P. torridus and 140.0, 85.0 kDa for P. oshimae. The purified enzymes were incubated with various polymeric substrates such as starch, pullulan, panose and isomaltose. The
product pattern, analyzed by HPLC, showed that in all cases glucose was formed as the sole product of hydrolysis. The purified
glucoamylases were optimally active at pH 2.0 and 90 °C and have an isoelectric points (pI) between 4.5 and 4.8. Enzymatic
activity was detected even at pH 1.0 and 100 °C. The glucoamylases were thermostable at elevated temperature with a half-life
of 24 h at 90 °C for both P. torridus and T. acidophilum, and 20 h at 90 °C for P. oshimae. The enzyme system of T. acidophilum has a lower K
m value for soluble starch (1.06 mg/ml) than the enzymes from P. oshimae and P. torridus (4.35 mg/ml and 2.5 mg/ml), respectively. Enzyme activity was not affected by Na +, Mg ++, Ca ++, Ni ++, Zn ++, Fe ++, EDTA and DTT.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
A serine protease and an enzyme preparation consisting of six chitinases, previously semi-purified from a liquid culture of Paecilomyces lilacinus strain 251, were applied to Meloidogyne javanica eggs to study the effect of the enzymes on eggshell structures. Transmission electron microscopic studies revealed that the protease and chitinases drastically altered the eggshell structures when applied individually or in combination. In the protease-treated eggs, the lipid layer disappeared and the chitin layer was thinner than in the control. The eggs treated with chitinases displayed large vacuoles in the chitin layer, and the vitelline layer was split and had lost its integrity. The major changes in the eggshell structures occurred by the combined effect of P. lilacinus protease and chitinases. The lipid layer was destroyed; the chitin layer hydrolyzed and the vitelline layer had lost integrity. The effect of P. lilacinus protease and chitinase enzymes on the hatching of M. javanica juveniles was also compared with a commercially available bacterial chitinase. The P. lilacinus protease and chitinase enzymes, either individually or in combination, reduced hatching of M. javanica juveniles whereas a commercial bacterial chitinase had an enhancing effect. Some juveniles hatched when the eggs were exposed to a fungal protease and chitinase mixture. We also established that P. lilacinus chitinases retained their activity in the presence of endogenous protease activity. 相似文献
|