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1.
Three species, Zygophyllum album L., Z. coccineum L. and Z. simplex L. , from family Zygophyllaceae were collected from two locations in Egypt to study their response to environmental conditions. Organic solutes (amino acids, soluble proteins and soluble sugars) and inorganic solutes (Na +, K +, Ca 2+, Mg 2+, Cl ?, PO 43? and SO 42?) were estimated to study their role in osmotic adjustment under the effect of drought and salinity. The study showed that Z. coccineum is most tolerant for drought and salinity than Z. simplex. Z. coccineum was dependent on soluble proteins and soluble sugars, to increase its content of bound water, to undergo water deficit in desert. Z. simplex accumulated inorganic solutes more than Z. coccineum and less organic solutes. Amino acids content increased in Z. coccineum and Z. simplex survived in saline conditions to play a role in osmotic adjustment. Under the effect of salinity, all the studied species showed a tendency and high capacity to accumulate inorganic solutes. The main inorganic salutes were Ca 2+, Mg 2+ and Cl ?. The role of Na + was less than Ca 2+ and Mg 2+. Z. album and Z. simplex preferred Mg 2+ more than Z. coccineum which preferred Ca 2+. 相似文献
2.
Azadirachtin (Az), as a botanical insecticide, is relatively safe and biodegradable. It affects a wide vaariety of biological
processes, including the reduction of feeding, suspension of molting, death of larvae and pupae, and sterility of emerged
adults in a dose-dependent manner. However, the mode of action of this toxin remains obscure. By using ion chromatography,
we analyzed changes in six inorganic cation (Li +, Na +, NH 4
+, K +, Mg 2+, and Ca 2+) distributions of the whole body and hemolymph in Ostrinia furnacalis (G.) after exposure to sublethal doses of Az. The results showed that Az dramatically interfered with Na +, NH 4
+, K +, Mg 2+, and Ca 2+ distributions in hemolymph of O. furnacalis (G.) and concentrations of these five cations dramatically increased. However, in the whole body, the levels of K +, Mg 2+, and Ca 2+ significantly, decreased after exposure to Az, except that Na + and NH 4
+ remained constant. Li + was undetected in both the control and treated groups in the whole body and hemolymph. It is suggested that Az exerts its
insecticidal effects on O. furnacalis (G.) by interfering with the inorganic cation distributions related to ion channels. 相似文献
3.
Cellular pH estimated from cell extract pH, and the ion compositions of major inorganic ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl ?, Br ?, NO 3?, S0 42‐) were studied by ion chromatography in 15 species of 4 orders (Cladophorales, Codiales, Siphonocladales and Ulvales) of Ulvophyceae and 49 species of 8 orders (Bangiales, Ceramiales, Corallinales, Cryptonemiales, Gelidiales, Gigartinales, Nemaliales and Rhodymeniales) of Rhodophyceae. Among the Rhodophyceae, relatively low intracellular pH (approximately 2.0 within cells) and high concentration of S0 42‐ was demonstrated in Plocamium telfairiae(Harvey) Harvey. Furthermore, five species of Hypnea Lamouroux were shown to contain high concentrations of S0 42‐ balanced by relatively high concentrations of Na +. Among the Ulvophyceae, Codium cylindricum Holmes and Ulva pertusa Kjellman contained high concentrations of S0 42‐ balanced by relatively high concentrations of Mg 2+. 相似文献
4.
The accumulation of inorganic and organic osmolytes and their role in osmotic adjustment were investigated in roots and leaves
of vetiver grass ( Vetiveria zizanioides) seedlings stressed with 100, 200, and 300 mM NaCl for 9 days. The results showed that, although the contents of inorganic
(K +, Na +, Ca 2+, Mg 2+, Cl −, NO 3−, SO 42− and H 2PO 3−)) and organic (soluble sugar, organic acids, and free amino acids) osmolytes all increased with NaCl concentration, the contribution
of inorganic ions (mainly Na +, K +, and Cl −) to osmotic adjustment was higher (71.50–80.56% of total) than that of organic solutes (19.43–28.50%). The contribution of
inorganic ions increased and that of organic solutes decreased in roots with the enhanced NaCl concentration, whereas the
case in leaves was opposite. On the other hand, the osmotic adjustment was only effective for vetiver grass seedlings under
moderate saline stress (less than 200 mM NaCl). 相似文献
5.
The effects of optimal sources and concentrations of major nutrients (supplying N, S, P, K +, Na +, Ca 2+, Mg 2+, and inorganic carbon) and organic buffers on growth and secondary metabolite accumulation in Scytonema ocellatum strain FF-66-3 were determined. Nitrate, phosphate, magnesium, and sulfur had no specific stimulatory or inhibitory effects on scytophycin accumulation within the range of concentrations that supported optimal growth. Calcium concentrations greater than those required for growth (0.1 mM) stimulated scytophycin accumulation. Sodium carbonate concentrations in excess of 0.25 mM strongly inhibited growth. Ammonium (2.5 mM) inhibited both growth and product formation. 3-[N-Morpholino]propanesulfonic acid at 3–5 mM effectively controlled pH and facilitated both growth and product formation. 相似文献
6.
Kochia sieversiana (Pall.) C. A. M., a naturally alkali-resistant halophyte, was chosen as the test organism for our research. The seedlings
of K. sieversiana were treated with varying (0–400 mM) salt stress (1:1 molar ratio of NaCl to Na 2SO 4) and alkali stress (1:1 molar ratio of NaHCO 3 to Na 2CO 3). The concentrations of various solutes in fresh shoots, including Na +, K +, Ca 2+, Mg 2+, Cl −, SO 42−, NO 3−, H 2PO 3−, betaine, proline, soluble sugar (SS), and organic acid (OA), were determined. The water content (WC) of the shoots was calculated
and the OA components were analyzed. Finally, the osmotic adjustment and ion balance traits in the shoots of K. sieversiana were explored. The results showed that the WC of K. sieversiana remained higher than 6 [g g −1 Dry weight (DW)] even under the highest salt or alkali stress. At salinity levels >240 mM, proline concentrations increased
dramatically, with rising salinity. We proposed that this was not a simple response to osmotic stress. The concentrations
of Na + and K + all increased with increasing salinity, which implies that there was no competitive inhibition for absorption of either in
K. sieversiana. Based on our results, the osmotic adjustment feature of salt stress was similar to that of alkali stress in the shoots of
K. sieversiana. The shared essential features were that the shoots maintained a state of high WC, OA, Na +, K + and other inorganic ions, accumulated largely in the vacuoles, and betaine, accumulated in cytoplasm. On the other hand,
the ionic balance mechanisms under both stresses were different. Under salt stress, K. sieversiana accumulated OA and inorganic ions to maintain the intracellular ionic equilibrium, with close to equal contributions of OA
and inorganic ions to anion. However, under alkali stress, OA was the dominant factor in maintaining ionic equilibrium. The
contribution of OA to anion was as high as 84.2%, and the contribution of inorganic anions to anion was only 15.8%. We found
that the physiological responses of K. sieversiana to salt and alkali stresses were unique, and that mechanisms existed in it that were different from other naturally alkali-resistant
gramineous plants, such as Aneurolepidium chinense, Puccinellia tenuiflora.
Responsible Editor: John McPherson Cheeseman. 相似文献
7.
At 0°C, when Na + was the only cation present in the incubation medium, increasing the Na + concentration from 3 to 10 m M enhanced the affinity of [ 3H]l-[2-(di-phenylmethoxy)ethyl]-4-(3-phenyl-2-propenyl)piperazine ([ 3H]GBR 12783) for the specific binding site present in rat striatal membranes without affecting the 5 max. For higher Na + concentrations, specific binding values plateaued and then slightly decreased at 130 m M Na +. In a 10 m M Na + medium, the KD and the B max were, respectively, 0.23 n M and 12.9 pmol/mg of protein. In the presence of 0.4 n M [ 3H]GBR 12783, the half-maximal specific binding occurred at 5 m M Na +. A similar Na + dependence was observed at 20°C. Scatchard plots indicated that K +, Ca 2+, Mg 2+, and Tris + acted like competitive inhibitors of the specific binding of [ 3H]GBR 12783. The inhibitory potency of various cations (K +, Ca 2+, Mg 2+, Tris +, Li + and choline) was enhanced when the Na + concentration was decreased from 130 to 10 m M. In a 10 m M Na + medium, the rank order of inhibitory potency was Ca 2+ (0.13 m M) > Mg 2+ > Tris + > K + (15 m M). The requirement for Na + was rather specific, because none of the other cations acted as a substitute for Na +. No anionic requirement was found: Cl -, Br -, and F - were equipotent. These results suggest that low Na + concentrations are required for maximal binding; higher Na + concentrations protect the specific binding site against the inhibitory effect of other cations. 相似文献
8.
Essentially all bacteria have genes for toxic metal ion resistances and these include those for Ag+, AsO
−2
, AsO
3−4
, Cd2+, Co2+, CrO
2−4
, Cu2+, Hg2+, Ni2+, Pb2+, TeO
2−3
, Tl+ and Zn2+. The largest group of resistance systems functions by energy-dependent efflux of toxic ions. Fewer involve enzymatic transformations (oxidation, reduction, methylation, and demethylation) or metal-binding proteins (for example, metallothionein SmtA, chaperone CopZ and periplasmic silver binding protein SilE). Some of the efflux resistance systems are ATPases and others are chemiosmotic ion/proton exchangers. For example, Cd2+-efflux pumps of bacteria are either inner membrane P-type ATPases or three polypeptide RND chemiosmotic complexes consisting of an inner membrane pump, a periplasmic-bridging protein and an outer membrane channel. In addition to the best studied three-polypeptide chemiosmotic system, Czc (Cd2+, Zn2+, and Co2), others are known that efflux Ag+, Cu+, Ni2+, and Zn2+. Resistance to inorganic mercury, Hg2+ (and to organomercurials, such as CH3Hg+ and phenylmercury) involve a series of metal-binding and membrane transport proteins as well as the enzymes mercuric reductase and organomercurial lyase, which overall convert more toxic to less toxic forms. Arsenic resistance and metabolizing systems occur in three patterns, the widely-found ars operon that is present in most bacterial genomes and many plasmids, the more recently recognized arr genes for the periplasmic arsenate reductase that functions in anaerobic respiration as a terminal electron acceptor, and the aso genes for the periplasmic arsenite oxidase that functions as an initial electron donor in aerobic resistance to arsenite. 相似文献
9.
AbstractThis paper examines the inorganic complexing capacity of seawater, where chloride and sulfate ions are present in high concentration, towards mono- di- and tri-organotin(IV) cations which show a different trend of acidity, depending on cation charges, and a corresponding tendency to hydrolysis. By considering hydrolytic species and chloride and sulphate complex formation, a basic inorganic speciation model of organotins in synthetic seawater (Na +, K +, Ca 2+, Mg 2+, Cl ?, SO 42?) has been built up. The model has been extended to also consider interactions of organotins with carbonate and fluoride ions, which are other important components of seawater. Because of the strength of hydrolysis processes, the main complexes formed are in general mixed hydroxo-species. No species are formed by organotin cations and/or their hydroxo-species with fluoride owing to their very low concentration in fluoride, in comparison to the other components of seawater. In order to simplify calculations and to establish a cumulative inorganic binding capacity for seawater, we applied a chemical complexation model, according to which the major inorganic components of seawater are considered as a single salt BA. 相似文献
10.
Glutathione S‐transferases (GSTs) are the superfamily of multifunctional detoxification isoenzymes and play important role cellular signaling. The present article focuses on the role of Cd 2+, Cu 2+, Zn 2+, and Ag + in vitro inhibition of GST. For this purpose, GST was purified from Van Lake fish ( Chalcalburnus tarichii Pallas) gills with 110.664 EU mg ?1 specific activity and 79.6% yield using GSH‐agarose affinity chromatographic method. The metal ions were tested at various concentrations on in vitro GST activity. IC 50 values were found for Cd +2, Cu +2, Zn +2, Ag + as 450.32, 320.25, 1510.13, and 16.43 μM, respectively. K i constants were calculated as 197.05 ± 105.23, 333.10 ± 152.76, 1670.21 ± 665.43, and 0.433 ± 0.251 μM, respectively. Ag + showed better inhibitory effect compared with the other metal ions. The inhibition mechanisms of Cd 2+ and Cu 2+ were non‐competitive, whereas Zn 2+ and Ag + were competitive. Co 2+, Cr 2+, Pb 2+, and Fe 3+ had no inhibitory activity on GST. 相似文献
11.
Acetone fractionation of Bacillus lentus culture filtrate yielded the highest -amylase activity and the 66.6% fraction reached 13-fold that of the crude enzyme preparation. Gel filtration and ion exchange chromatography afforded a pure -amylase (relative molecular mass, 42 000). The pure enzyme was highly active on starch and dextrin. It produced a mixture of oligosaccharides as major products of starch hydrolysis. Maximal activity was reached at 70° C and pH 6.1. Ca 2+, Na +, K + and Sr 2+ ions stabilized or slightly stimulated the enzyme whereas Ag +, Co 2+, Hg 2+, Zn 2+, Cd 2+ and Fe 3+ ions strongly inhibited the activity. The enzyme contained 16 amino acids, of which aspartic and glutamic acids were present in the highest proportions.
Correspondence to: S. H. Omar 相似文献
12.
The effects of an auxin herbicide, 2,4-D, at a concentration of 0.01 m M, on the K + uptake and efflux of excised roots of wheat ( Triticum aestivum L. cv. Rannaya) were investigated at different pH values. The K + movement was monitored with a K + ( 86Rb) tracer. In parallel experiments the ATPase activities of microsomal fractions were determined by the inorganic phosphate liberation method. 2,4-D inhibited the K + uptake especially at low pH, irrespective of whether Ca 2+ was present or not. No marked changes were observed in the K + efflux properties at pH values above 4. The inhibitory effect on K + uptake exhibited a correlation with the hydrocarbon solubility of the herbicide, but not with the 2,4-D-induced decrease of the ATPase activity. It is suggested that 2,4-D exerts a non-specific effect on the lipid-protein interactions, giving rise to a generalized alteration of the transport barrier properties of the plasma membrane even at as low a concentration as 0.01 m M. 相似文献
13.
The gene for a putative cation calcium exchanger (CCX) from Arabidopsis thaliana, AtCCX5, was cloned and its function was analyzed in yeast. Green fluorescent protein-tagged AtCCX5 expressed in yeast was localized in the plasma membrane and nuclear periphery. The yeast transformants expressing AtCCX5 were created and their growth in the presence of various cations (K +, Na +, Ca 2+, Mg 2+, Fe 2+, Cu 2+, Co 2+, Cd 2+, Mn 2+, Ba 2+, Ni 2+, Zn 2+, and Li +) were analyzed. AtCCX5 expression was found to affect the response to K + and Na + in yeast. The AtCCX5 transformant also showed a little better growth to Zn 2+. The yeast mutant 9.3 expressing AtCCX5 restored growth of the mutant on medium with low K + (0.5 mM), and also suppressed its Na + sensitivity. Ion uptake experiments showed that AtCCX5 mediated relatively high-affinity K + uptake and was also involved in Na + transport in yeast. Taken together, these findings suggest that the AtCCX5 is a novel transport protein involves in mediating high-affinity K + uptake and Na + transport in yeast. 相似文献
14.
Zn 2+ at 5 ppm and phosphate at 20 and 40 ppm improved the growth and nodulation of chickpea ( Cicer arietinum L.) at two levels of salinity (4.34 and 8.3 dS m –1). Augmentation with Zn 2+ at 5 ppm provided protection to the plant under saline conditions by reducing the Na +:K + ratio in the shoot. The shoot nitrogen content with 5 ppm Zn 2+ and 20 ppm phosphate was equal to that of a non-saline control. No significant effect on nitrogenase activity was observed. 相似文献
15.
Most of the fine root tips of boreal and temperate forests are colonized by ectomycorrhizal fungi. Thus ectomycorrhizal (ECM)
symbiosis is an important factor in supplying trees with water and a wide range of nutrients. ECM are frequently patchily
distributed and often form dense systems in small areas. One of the reasons for this uneven distribution might be a heterogeneous
and patchy distribution of nutrients. The present study compares the occurrence of ECM of Cortinarius obtusus, Lactarius decipiens, L. theiogalus, and Russula ochroleuca and soil nutrient concentrations at a micro-scale (1 cm 2) in the O F layer of a pure Norway spruce stand. In addition to the macronutrients K +, Mg 2+, Ca 2+, NO 3
−, NH 4
+, the concentrations of Na +, Fe 3++Mn 2+, Al 3+, Cl −, SO 4
2− are studied, as well as pH. Whereas Russula ochroleuca and Lactarius decipiens did not reveal any significant correlation with any of the tested nutrients or pH, the occurrence of L. theiogalus was significantly (p < 5 %) positively correlated with NH 4
+, K +, Na +, Mg 2+, Fe 3++Mn 2+, and pH. Cortinarius obtusus was positively correlated at the same significance level only with NH 4
+ and Mg 2+. 相似文献
16.
The Tl +-induced opening of the MPTP in Ca 2+-loaded rat liver mitochondria energized by respiration on the substrates succinate or glutamate plus malate was recorded as increased swelling and dissipation of mitochondrial membrane potential as well as decreased state
4, or state 3, or 2,4-dinitrophenol-stimulated respiration. These effects of Tl + increased in nitrate media containing monovalent cations in the order of Li + < NH 4+ ≤ Na + < K +. They were potentiated by inorganic phosphate and diminished by the MPTP inhibitors (ADP, CsA, Mg 2+, Li +, rotenone, EGTA, and ruthenium red) both individually and more potently in their combinations. Maximal swelling of both non-energized
and energized Ca 2+-loaded mitochondria in rotenone-free media is an indication of Ca 2+ uptake driven by respiration on mitochondrial endogenous substrates. It is suggested that Tl + (distinct from Cd 2+, Hg 2+, and other heavy metals and regardless of the used respiratory substrates) can stimulate opening of the MPTP only in the
presence of Ca 2+. We discuss the possible participation of Ca 2+-binding sites, located near the respiratory complex I and the adenine nucleotide translocase, in inducing opening of the
MPTP. 相似文献
17.
In the present paper, we show the existence of a furosemide-sensitive Na +-stimulated, Mg 2+-dependent ATPase activity in cell lysates of Malpighian tubular cells from Rhodnius prolixus, which could be the biochemical expression of the Na +-pump. The main characteristics of this activity are: (1) K0.5 for Na +=1.49±0.18 mM, (2) Vmax=2.8±0.1 nmol inorganic orthophosphate (Pi)·mg prot −1·min −1, (3) it is fully abolished by 2 mM furosemide, (4) it is insensitive to ouabain concentrations up to 10 −2 M, (5) it is sensitive to the presence of vanadate in the incubation medium indicating it to be a P-type ATPase, and (6) it is stimulated by nanomolar concentrations of Ca 2+ in the incubation medium. 相似文献
18.
采用盆栽试验,对彩叶草进行PEG-6000浓度为0(对照)、5%、10%、15%、20%(W/V)模拟干旱胁迫,研究在干旱胁迫下彩叶草的生长、渗透调节能力及抗氧化酶活性的变化。结果表明:与对照相比,随着PEG-6000浓度的增加,鲜质量、干质量、含水量、水势、根系脱氢酶活性、无机离子含量包括K+、Na+、Ca2+、Mg2+等均呈下降趋势;NO-3含量呈先下降后上升趋势;硝酸还原酶活性、可溶性蛋白含量、可溶性糖含量、超氧化物歧化酶活性均呈先上升后下降趋势;脯氨酸含量、游离氨基酸含量、过氧化物酶活性、过氧化氢酶活性、超氧阴离子(O-2·)产生速率、质膜透性则呈上升趋势。因此,模拟干旱胁迫对彩叶草生长有抑制作用,且随着PEG-6000浓度增加,其生长受抑制和水分胁迫程度加重;模拟干旱胁迫下,彩叶草不积累K+、Na+、Ca2+、Mg2+和NO-3等无机离子进行渗透调节,而积累脯氨酸、可溶性蛋白、可溶性糖、游离氨基酸等有机小分子物质进行渗透调节,但这4种小分子物质增加幅度不尽相同;轻度模拟干旱胁迫虽增强彩叶草抗氧化酶活性,但仍表现轻度的氧化伤害;重度模拟干旱胁迫加重彩叶草氧化伤害。研究结果可为彩叶草耐旱生理机制的研究积累资料,也为其节水型栽植和养护提供依据。 相似文献
19.
AbstractThe present study aims at evaluating a batch scale biosorption potential of Moringa oleifera leaves (MOL) for the removal of Pb(II) from aqueous solutions. The MOL biomass was characterized by FTIR, SEM, EDX, and BET. The impact of initial concentrations of Pb (II), adsorbent dosage, pH, contact time, coexisting inorganic ions (Ca 2+, Na +, K +, Mg 2+, CO 32?, HCO 3?, Cl ?), electrical conductivity (EC) and total dissolved salts (TDS) in water was investigated. The results revealed that maximum biosorption (45.83?mg/g) was achieved with adsorbent dosage 0.15?g/100?mL while highest removal (98.6%) was obtained at adsorbent biomass 1.0?g/100?mL and pH 6. The presence of coexisting inorganic ions in water showed a decline in Pb(II) removal (8.5% and 5%) depending on the concentrations of ions. The removal of Pb(II) by MOL decreased from 97% to 89% after five biosorption/desorption cycles with 0.3?M HCl solution. Freundlich model yielded a better fit for equilibrium data and the pseudo-second-order well described the kinetics of Pb(II) biosorption. FTIR spectra showed that –OH, C–H, –C–O, –C?=?O, and –O–C functional groups were involved in the biosorption of Pb(II). The change in Gibbs free energy (ΔG = ?28.10?kJ/mol) revealed that the biosorption process was favorable and thermodynamically driven. The results suggest MOL as a low cost, environment-friendly alternative biosorbent for the remediation of Pb(II) contaminated water. 相似文献
20.
A venacin, the resistance factor in oat roots against Ophiobolus graminis var. graminis, and a related triterpeneglycoside, aescin, inhibited the uptake of K + and Mg 2+ in the fungal mycelium both in phosphate and succinate buffers. The uptake of the cations in Neurospora crassa was similarly inhibited when the inhibitors were dissolved in phosphate or acetatebuffer, while no decrease in the uptake of K + and Mg 2+ was observed when the inhibitors were dissolved in succinate buffer. The uptake of cations in Aspergillus niger and Pythium irregulare was more or less unaffected by aescin. The uptake of inorganic phosphate was in no case inhibited, but some decrease of the accumulation of inorganic phosphate in Ophiobolus graminis and Ncurospora crassa due to inhibitor treatment in phosphate buffer was observed. No accumulation of Ca 2+ was observed in any of the tested fungi. 相似文献
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