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1.
Assessment of the Zn status of chickpea by plant analysis 总被引:1,自引:0,他引:1
Chickpea (Cicer arietinum L.) is extensively grown in areas where soils are deficient in zinc (Zn). To determine the response of chickpea to Zn nutrition and to diagnose Zn status in plant tissue, two glasshouse experiments were conducted using Zn-deficient siliceous sandy soil. In Experiment 1, two genotypes of desi chickpea (Dooen and Tyson) were grown at five Zn levels (0, 0.04, 0.2, 1.0 and 5.0 mg kg-1 of soil). After 4 weeks, no difference in growth and no visible symptoms of Zn deficiency were detected. After 6–8 weeks of growth, chlorosis of younger leaves and stipules occured in the Zn0 treatment, with shoot dry weight being only 24% of that recorded at the highest Zn level. Root growth increased from 0.52 g/plant when no Zn was applied to 1.04 g/plant in the treatment with 0.2 mg Zn kg-1 of soil; no response to further increase of Zn fertilization occurred. Zinc concentration in the whole shoot increased significantly with increased in Zn application. The critical Zn concentration in the shoot tissue, associated with 90% of maximum growth, was 20 mg kg-1 for both genotypes at flowering stage.In the second experiment, two genotypes of desi chickpea (Tyson and T-1587) were grown at three Zn levels (0, 0.5 and 2.5 mg kg-1 of soil) under two moisture regimes (field capacity 12% w/w, and water stress 4% w/w). Shoot growth was influenced by both Zn supply and water stress. The effect of water stress was severe in the 0.5 and 2.5 mg Zn treatments where shoot dry matter was reduced 52 and 46%, respectively. T-1587 was less sensitive to Zn deficiency and produced higher shoot dry weight than Tyson in the Zn0 treatment. Zinc concentration in shoots increased from 5 mg kg-1 when no Zn was applied to 40 mg kg-1 at the highest Zn level. The critical Zn concentration in shoots was 21 mg kg-1.The results of the two experiments showed that the critical concentration for Zn did not differ amongst the three cultivars used and was not affected by soil moisture. Similar studies should be undertaken with a wider number of genotypes to discover if a critical concentration of 20–21 mg kg-1 in the shoot can be used to diagose the Zn status of chickpea genotypes. 相似文献
2.
Recent studies with rats force-fed zinc-deficient diets containing various types of fat failed to demonstrate a role of zinc
in desaturation of linoleic acid. The present study was conducted to investigate the effect of zinc deficiency on desaturation
of linoleic acid in rats that were initially force-fed fat-free diets to stimulate activity of desaturases. Therefore, rats
were fed zinc-adequate and zinc-deficient fat-free diets for 6 d. After that period, the groups were divided and half of the
rats continued feeding the fat-free diet for another 3.5 d whereas the other half was switched to a fat diet by supplementing
the fat-free diet with 5% safflower oil. In order to assess desaturation of linoleic acid, fatty acid compositions of liver
phosphatidylcholine, ethanolamine, and-serine were considered, particularly levels of individual (n-6) polyunsaturated fatty
acids (PUFA). Levels of total and individual (n-6) PUFA were similar in zinc-adequate and zinc-deficient rats fed the fat-free
diet throughout the experiment. Addition of 5% safflower oil increased levels of total and individual (n-6) PUFA in both zinc-adequate
and zinc-deficient rats. However, total (n-6) PUFA in all types of phospholipids were higher in zinc-adequate rats than in
zinc-deficient rats. Additionally, in zinc-deficient rats there were changes of (n-6) PUFA levels typical for impaired Δ5
and Δ6 desaturation: linoleic acid and dihomo-γ-linolenic acid were elevated; arachidonic acid, docosatetraenoic acid, and
docosapentaenoic were lowered by zinc deficiency. Therefore, the study shows that zinc deficiency impairs desaturation of
linoleic acid in rats force-fed fat-free diets and therefore supports results from former convential zinc deficiency experiments
suggesting a role of zinc for desaturation of linoleic acid. 相似文献
3.
In 1985, Paterson and Bettger found hypoplastic hematopoiesis in severely zinc-deficient rats. Therefore, we investigated
plasma erythropoietin concentration in zinc-deficient rats. Forty 4-wk-old male Sprague-Dawley rats were assigned into 4 dietary
treatment groups of 10 for the 4-wk study: zinc-deficient group (4.5 mg zinc and 35 mg iron/kg; −Zn), iron-deficient group
(30 mg zinc/kg, no supplemental iron; −Fe), zinc/iron-deficient group (4.5 mg zinc/kg, no supplemental iron; −Zn−Fe), and
control group (AIN-93G; Cont). Water intake determined at d 19 was similar among all treatment groups. At d 27–28, bioimpedance
was measured. The intracellular water/extracellular water ratio was significantly increased in the −Zn group (p<0.05). Compared to the Cont, group, the plasma erythropoietin concentration was increased by iron deficiency and decreased
by zinc deficiency (p<0.01). Hematocrit was significantly decreased in both the −Fe and −Zn−Fe groups and was significantly increased in the −Zn
group (p<0.01). Transferrin saturation in the −Fe and −Zn−Fe groups was significantly lower than the Cont group (p<0.01), and that of the −Zn group was highest among all groups. The low plasma erythropoietin concentration might account
for depressed hematopoiesis associated with zinc deficiency. 相似文献
4.
Ton H. J. Naber Cornelis J. A. van den Hamer Wim J. M. van den Broek Jan H. M. van Tongeren 《Biological trace element research》1992,35(2):137-152
In zinc deficiency, the function of leukocytes is impaired. However, the results of studies on the zinc concentration of blood
cells in zinc deficiency are conflicting, probably in part because of technical and analytical problems. The aim of this study
was to investigate, under standard conditions, the uptake of65Zn-labeled zinc by blood cells, taken from zinc-deficient rats and from rats in which an inflammation is induced. In both
conditions, the serum zinc concentration is reduced. In clinical practice, this makes it difficult to determine whether the
decrease in serum zinc is the result of a real or an apparent zinc deficiency. In stress, like an inflammatory disease, the
decrease of zinc reflects an apparent zinc deficiency because of redistribution of serum zinc into the liver and because of
decrease in serum albumin concentration. Over 70% of the serum zinc is bound to albumin. Blood cells from zinc-deficient and
control rats were isolated using a discontinuous Percoll gradient and incubated under nearly physiological conditions in a65Zn-containing medium. A significant increase in the in vitro uptake of65Zn-labeled zinc by the blood cells of zinc-deficient rats was seen: erythrocytes 1.3, mononuclear cells 2.0, and polymorphonuclear
cells 2.6 times the control values. During inflammation, no change in65Zn-labeled zinc uptake by erythrocytes and mononuclear cells was demonstrated after 2 d, although the serum zinc and albumin
concentrations were decreased, but a small but significant increase in zinc uptake by polymorphonuclear cells was observed.
This study of65Zn uptake in vitro under standard conditions may prove of value for distinguishing in patients real zinc deficiency from apparent
zinc deficiency owing to, e.g., stress, although additional experiments should be performed.
A part of this study has been presented at the Meeting of The American Gastroenterological Association on May 12–18, 1990,
San Antonio, TX, and has been published in abstract inGastroenterology
98 suppl., A423. 相似文献
5.
Variation in carbon isotope discrimination within and among Sphagnum species in a temperate wetland 总被引:1,自引:0,他引:1
S. K. Rice 《Oecologia》2000,123(1):1-8
Field samples of bryophytes are highly variable in carbon isotope discrimination values (Δ, a measure of 13CO2 uptake relative to 12CO2), but it is unknown what affects Δ under field conditions, or how variation in Δ relates to bryophyte performance. This study
employed field and greenhouse common garden studies to evaluate the influence of microsite, seasonal, and genetic variation
on Δ in peatmosses. Three species of Sphagnum that occupy hollow (S. recurvum), carpet (S. palustre), and hummock (S. tenerum) habitats were sampled for relative growth rates (RGR), C:N ratio, and Δ throughout a growing season. Values of Δ ranged
from 19.0 to 27.1‰. This variation was unrelated to species (P=0.61). However, Δ varied seasonally (P<0.001), with lower discrimination in the spring (mean 22.5‰), followed by summer (23.8‰) and winter (24.7‰). There was also
significant microsite variation (P=0.015) which disappeared when plants were grown in a common garden. In both spring and summer, microsite variation in Δ was
inversely related to RGR (P<0.001), but unrelated to C:N ratios (P>0.08). These results suggest that environmental, not genetic, variation at microsites affects Δ in non-vascular plants. However,
environmental control of Δ is unlike that in vascular plants where water limitation lowers chloroplastic demand and increases
resistance to carbon uptake. In non-vascular plants, water limitation lowers chloroplastic demand and decreases resistance
to carbon uptake. These processes have additive effects and generate high spatial and seasonal variability in Δ.
Received: 29 April 1999 / Accepted: 8 November 1999 相似文献
6.
In previous studies, water stress has induced variable and sometimes contradictory changes in respiration. We used isothermal calorimetry to measure the response of foliar respiration to water deficit in nine eucalypt genotypes. Specific growth rates (R
SG) of shoots and leaves of variable age were measured independently, and the data were applied to both the growth-maintenance and enthalpy balance models. We calculated the oxidation state of respiratory substrate and the enthalpy change for the conversion of substrate carbon to biomass (ΔH
B). Moderate water stress reduced the R
SG of shoots by 38% (P<0.01) and carbon conversion efficiency by 15% (P<0.05). The relationship between carbon conversion efficiency and R
SG was not affected by water deficit for shoots, but was significantly altered for leaves. Water deficit increased maintenance respiration by about 23% (P<0.001). The growth coefficient of respiration was not significantly altered. However, changes in oxidation states of substrate and biomass suggest that the energy requirements of biosynthesis were increased under water stress. Our results confirm that carbohydrates are the major respiratory substrates in growing tissues, though mature leaves utilized a substantial component of more reduced substrate. Mature leaves had variable oxidation states for respiration substrate, which indicates a variable relationship between CO2 evolution and ATP production. Measured ΔH
B in shoots and leaves were too small for reliable estimation of R
SG by the enthalpy balance model. We also found significant effects of water stress on the oxidation state of substrate and ΔH
B. 相似文献
7.
Hybrids of willow (Salix spp.) are today grown as biomass crops for energy in several cool-temperate regions including Sweden. These trees have great
growth potential also under warmer climates, but may suffer from drought and heat. Research on tree growth under drought has
often focused on the responses to permanent water stress. Less attention has been paid to the effects of temporary water stress
on tree growth, although periods of strong water shortage are recurrent in many regions of the world. We performed a greenhouse
experiment to assess the impact of five treatments including permanent (PWS; 30 days of water shortage) and temporary (TWS;
4–12 days of water shortage followed by normal watering) water stress on growth and leaf traits of 15 Salix genotypes. Plant biomass and height increment decreased across treatments in the order control (well-watered) > TWS > PWS,
but there was also a significant genotype × treatment interaction. The pattern in growth traits was not directly reflected
by the leaf traits, for which there was no significant genotype × treatment interaction (except for leaf angle). The significant
genotype × treatment interactions for growth traits indicate a potential for breeding. Permanent water shortage does not necessarily
represent an appropriate environment for the selection of genotypes for environments characterised by temporary water stress. 相似文献
8.
Photosynthetic parameters and leaf water potential of five common bean genotypes under mild water deficit 总被引:2,自引:0,他引:2
The leaf water potential, gas exchange and chlorophyll fluorescence were evaluated in five common bean (Phaseolus vulgaris) genotypes A222, A320, BAT477, Carioca and Ouro Negro subjected to moderate water deficit. At the maximum water deficit (10
d of water withholding), the leaf water potential of genotypes A320 and A222 was higher (−0.35 and −0.50 MPa) when compared
to the other genotypes (−0.67 to −0.77 MPa). The stomatal conductance and net photosynthetic rate were significantly reduced
in all genotypes due to the water deficit. The greater reduction in stomatal conductance of A320 under drought resulted in
high intrinsic water use efficiency. Mild water deficit affected the photochemical apparatus in bean genotypes probably by
down-regulation since plants did not show photoinhibition. The photochemical apparatus of A222 and A320 genotypes was more
sensitive to drought stress, showing reduced apparent electron transport even after the recovery of plant water status. On
the other hand, even after 10 d of water withholding, the maximum efficiency of photosystem 2 was not affected, what suggest
efficiency of the photoprotection mechanisms. 相似文献
9.
The present study was conducted to investigate the effect of zinc deficiency on fatty acid desaturation in rats fed two different
types of dietary fat, a mixture of coconut oil and safflower oil (7∶1, w/w, “coconut oil diet”) or linseed oil (“linseed oil
diet”). In order to ensure an adequate food intake, all rats were force-fed by gastric tube. Zinc deficiency caused statistical
significant reducion of Δ9-desaturase activity in liver microsomes of rats fed coconut oil diet and tendencial reduction (p<0.15) in rats fed linseed oil diet compared with control rats fed diets with the same type of fat. In agreement with this
effect, zinc deficiency in the rats fed both types of dietary fat increased the ratio between total saturated and total monounsaturated
fatty in liver phospholipids and liver microsomes. Zinc deficient rats on the coconut oil diet had unchanged Δ6-desaturase
activity with linoleic acid as substrate and lowered activity with α-linolenic acid as substrate. In contrast, zinc deficient
rats on the linseed oil diet had increased Δ6-desaturase activity with linoleic acid as substrate and unchanged activity with
α-linolenic acid. Because linoleic acid is the main substrate for Δ6-desaturase in the rats fed coconut oil diet, and α-linolenic
acid is the main substrate in the rats fed linseed oil diet, it is concluded that in vivo Δ6-desaturation was not changed
by zinc deficiency in the rats fed both types of dietary fat. Activity of Δ5-desaturase was also not changed by zinc deficiency
in the rats fed both dietary fats. Levels of fatty acids in liver phospholipids and microsomes derived by Δ4-, Δ5-, and Δ6-desaturation
were not consistently changed by zinc deficiency in the rats fed both types of dietary fat. Thus, the enzyme studies and also
fatty acid composition data of liver phospholipids and microsomes indicate that zinc deficiency does not considerably disturb
desaturation of linoleic and α-linolenic acid. Therefore, it is suggested that similarities between deficiencies of zinc and
essential fatty acids described in literature are not due to disturbed desaturation of linoleic acid in zinc deficiency. The
present study also indicates that zinc deficiency enhances incorporation of eicosapentaenoic acid into phosphatidylcholine
of rats fed diets with large amounts ofn-3 polyunsaturated fatty acids. 相似文献
10.
Chickpea genotypes differ in their sensitivity to Zn deficiency 总被引:4,自引:1,他引:3
Zinc (Zn) deficiency is common in most of the chickpea growing areas of the world and growing Zn-efficient genotypes on Zn-deficient soil is a benign approach of universal interest. Response of 13 chickpea genotypes (10 desi and 3 kabuli) to Zn nutrition was studied in a pot experiment under glasshouse conditions. Plants were grown in a Zn-deficient siliceous sand for 6 weeks and fertilized with 0 (Zn–) and 2.5 mg Zn per kg soil (Zn+). When grown with no added Zn, Zn deficiency symptoms (chlorosis of younger leaves and stipules followed by necrosis of leaf margins) appeared 3–4 weeks after planting and were more apparent in cultivars Tyson, Amethyst and Dooen than Kaniva and T-1587. Zn deficiency reduced shoot growth, but it was less affected in breeding lines T-1587 and CTS 11308 than cultivars Tyson, Dooen, Amethyst and Barwon. Among all genotypes, Tyson produced the lowest root dry weight in Zn– treatment. Zinc efficiency based on shoot dry weight showed marked differences among genotypes; breeding lines CTS-60543, CTS-11308 and T-1587 were 2-fold more Zn-efficient than cultivars Tyson and Dooen. A higher Zn accumulation per plant and higher Zn uptake per g. of root dry weight were recorded in T-1587 and CTS-11308 when compared with Tyson. Root:shoot ratio was increased and proportionally more Zn was transported to the shoot when the soil was deficient. Cultivars that were very sensitive to Zn deficiency tended to have their root:shoot ratio increased by Zn deficiency more than less sensitive cultivars. The insensitive lines T-1587 and CTS-11308 transported more than 70% of the total absorbed Zn to the shoot. It is concluded that chickpea genotypes vary in their sensitivity to Zn deficiency. Advanced breeding lines T-1587 and CTS-11308 are relatively more Zn-efficient compared with Australian chickpea cultivar Tyson. Zn efficiency in chickpea genotypes is probably related to an efficient Zn absorption coupled with a better root to shoot transport. 相似文献
11.
Leaf carbon isotope discrimination and nitrogen content for riparian trees along elevational transects 总被引:20,自引:0,他引:20
Leaf carbon isotope discrimination (Δ), seasonal estimates of the leaf-to-air water vapor gradient on a molar basis (ω),
and leaf nitrogen contents were examined in three riparian tree species (Populus fremontii, P. angustifolia, and Salix exigua) along elevational transects in northern and southern Utah USA (1500–2670 m and 600–1820 m elevational gradients, respectively).
The ω values decreased with elevation for all species along transects. Plants growing at higher elevations exhibited lower
Δ values than plants at lower elevations (P. fremontii, 22.9‰ and 19.5‰, respectively; P. angustifolia, 23.2‰ and 19.2‰, respectively; and S.␣exigua, 21.1‰ and 19.1‰, respectively). Leaf nitrogen content increased with elevation for all species, suggesting that photosynthetic
capacity at a given intercellular carbon dioxide concentration was greater at higher elevations. Leaf Δ and nitrogen content
values were highly correlated, implying that leaves with higher photosynthetic capacities also had lower intercellular carbon
dioxide concentrations. No significant interannual differences were detected in carbon isotope discrimination.
Received: 25 February 1996 / Accepted: 8 September 1996 相似文献
12.
Elzbieta I. Szczurek Chris S. Bjornsson Amy D. Noto Carla G. Taylor 《Journal of trace elements in medicine and biology》2009,23(3):176-182
Metallothionein (MT) is important for heavy metals and free radical protection in the kidney. MT is responsive to zinc and primarily localized within the renal cortex. However, site-specific renal responses to dietary zinc repletion are understudied. The objective of this study was to examine the effects of dietary zinc deficiency and repletion on renal MT concentration and immunolocalization in rats. Weanling male Sprague Dawley rats were randomly assigned to either a zinc-deficient, zinc control, or pair-fed to zinc-deficient group. Half of the zinc-deficient and pair-fed rats were repleted with the control diet ad libitum for an additional 24 h. Renal tissue samples were assessed for total zinc, MT concentrations and MT immunostaining. Dietary zinc deficiency reduced renal zinc and MT concentrations, and attenuated intensity and localization of MT. Dietary zinc repletion for 24 h restored renal zinc and MT concentrations, the latter primarily in the proximal convoluted tubules of the cortex. Concentrations of renal MT, but not zinc, were elevated by diet restriction and MT (μg/mg protein) and partially normalized by 24 h diet repletion. In conclusion, renal MT modification due to zinc deficiency or diet restriction can be rapidly normalized in a site-specific manner with normal dietary zinc intake. The results support a role for MT in kidney homeostasis, in particular at the level of the proximal tubules in the cortex. The speed of MT repletion may have clinical implications for dietary zinc in the treatment of acute and chronic renal pathology due to toxins and free radicals. 相似文献
13.
Oztürk A Baltaci AK Bediz CS Mogulkoc R Güngör S 《Biological trace element research》2003,96(1-3):255-262
The present study was designed to investigate the effects of zinc and/or melatonin deficiency on rat testes. A total of 24
adult male Sprague-Dawley rats were used in this study. The rats were divided into four groups of six rats each, as follows:
(I) controls, (II) zinc deficient, (III) pinealectomized, zinc normal, and (IV) pinealectomized, zinc deficient. The plasma
zinc levels in the control group were higher than in all the other groups (p<0.01), and those of the zinc-deficient groups II and IV were significantly lower than for group III (p<0.01). The melatonin levels in the controls were also significantly higher than for all other groups (p<0.01) There was no significant difference in sperm production between the controls and the group of animals that had no epiphysis.
A significant suppression was observed in the spermatogenetic activity of the zinc-deficient groups (p<0.01). The suppression was higher in group II than in group IV. These results indicate that testicular damage caused by zinc
deficiency may be reduced by melatonin deficiency. 相似文献
14.
Eight chickpea advanced breeding lines (ABLs) and their parents were evaluated for osmotic adjustment (OA), leaf carbohydrates and gas exchange under dryland field . These (ABLs) were derived from crosses between CTS 60543 x Kaniva and Tyson x Kaniva. Mean leaf water potential (LWP) fell down from -1.00 MPa at pre-stress level to about -2.25 MPa during terminal stress. Relative water content (RWC) showed periodic changes with alternate decrease or increase at certain interval, which also influenced the values of OA (low or high) in number of genotypes e.g. Kaniva, CTS 60543, Tyson and M 75. Significant variation in OA ranging 0.45 to 0.88 MPa was observed at high level of stress at -2.5 MPa. However, none of the genotypes showed stability of OA over the period of stress. Leaf starch declined even at mild stress (LWP, -1.6 MPa) resulting in an increase in hexose sugars and activation state of sucrose-phosphate synthase (SPS) that led to accumulation of sucrose. Both photosynthesis (Pmax) and transpiration decreased concurrently in two chickpea lines M 129 and Tyson with increasing water stress. However, rate of decline in the photosynthesis slowed down even drought was further intensified. The observed periodic changes in OA, RWC and photosynthesis appeared to be associated with drought-induced changes in SPS and carbohydrates which modify water uptake of the leaves. 相似文献
15.
Abdulkerim Kasim Baltaci Hakki Gokbel Rasim Mogulkoc Nilsel Okudan Kagan Ucok Ihsan Halifeoglu 《Biological trace element research》2010,134(1):79-83
The objective of the present study was to determine the effects of exercise and zinc deficiency on some elements in rats.
Forty adult male Sprague–Dawley species male rats were allocated to four groups as follows: Group 1: control, Group 2: zinc-deficient,
Group 3: exercise in which exercise group fed with a normal diet, Group 4: zinc-deficient exercise, exercise group fed by
a zinc-deficient diet for 15 days. After the procedure ended, rats in groups 3 and 4 were exercised on the treadmill for 60 min
at a speed of 6 m/min until the exhaustion. The rats were decapitated 48 h after exercise together with their controls, and
blood samples were collected to determine copper (Cu), iron (Fe), magnesium (Mg), calcium (Ca), and phosphorus (P) levels.
The highest Cu and Fe values in the serum were obtained in group 2 (p < 0.01). The levels of these elements in group 4 were lower than those in group 2 and higher than the levels in groups 1
and 3 (p < 0.01). Serum Mg levels did not differ significantly between groups. Group 4 had the lowest serum Ca and P levels (p < 0.01). These same parameters in Group 2 were higher than those in group 4 but significantly lower than those in groups
1 and 3 (p < 0.01). There was no significant difference between Ca and P levels of groups 1 and 3. The results of the study indicate
that zinc deficiency adversely affects copper, iron, calcium, and phosphorus mechanisms and that these adverse effects much
more marked after an effort exercise. 相似文献
16.
Stable isotope measurements are employed extensively in plant–water relations research to investigate physiological and hydrological
processes from whole plant to ecosystem scales. Stable isotopes of hydrogen and oxygen are routinely measured to identify
plant source water. This application relies on the assumption that no fractionation of oxygen and hydrogen isotopes in water
occurs during uptake by roots. However, a large fraction of the water taken up through roots in halophytic and xerophytic
plants transverses cell membranes in the endodermis before entering the root xylem. Passage of water through this symplastic
pathway has been hypothesized to cause fractionation leading to a decrease in 2H of root xylem water relative to that in the surrounding soil medium. We examined 16 woody halophytic and xerophytic plant
species in controlled conditions for evidence of hydrogen isotope fractionation during uptake at the root–soil interface.
Isotopic separation (Δ2H = δ2Hsoil water − δ2Hxylem water) ranging from 3‰ to 9‰ was observed in 12 species. A significant positive correlation between salinity tolerance and the
magnitude of Δ2H was observed. Water in whole stem segments, sapwood, and roots had significantly lower δ2H values relative to soil water in Prosopis velutina Woot., the species expressing the greatest Δ2H values among the 16 species examined. Pressurized water flow through intact root systems of Artemisia tridentata Nutt. and Atriplex canescens (Pursh) Nutt. caused the δ2H values to decrease as flow rate increased. This relationship was not observed in P. velutina. Destroying the plasma membranes of root cells by excessive heat from boiling did not significantly alter the relationship
between δ2H of expressed water and flow rate. In light of these results, care should be taken when using the stable isotope method to
examine source-water use in halophytic and xerophytic species. 相似文献
17.
The effect of dietary zinc deficiency on the mossy fiber zinc content of the rat hippocampus was investigated using PIXE (Particle Induced X-Ray Emission) spectroscopy. Using the proton microbeam (60 X 60 microns), 2 mm line-scans were made on hippocampal sections and the data were expressed as absolute zinc concentrations. Values of 55 and 136 ppm (dry weight) were found for the mean background zinc level and the maximum mossy fiber zinc level, respectively, in animals fed a control diet containing 50 ppm zinc. Treatment of these animals with dithizone caused about 50% reduction in the maximum mossy fiber zinc level. Feeding a zinc-deficient diet for 28 days did not cause a decrease in the mossy fiber zinc level, however, feeding the zinc-deficient diet for 90 days reduced the maximum mossy fiber zinc level by about 30%. The results are discussed in relation to the behavioral abnormalities that have been observed in zinc-deficient animals. 相似文献
18.
Susceptibility to kainate-induced seizures is enhanced by zinc deficiency. To evaluate kainate-induced excitotoxicity in zinc deficiency, the relationship between kainate-induced seizures and hippocampal cell death was examined in control and zinc-deficient mice. Mice were fed a control and zinc-deficient diet for 4 weeks, and then intraperitoneally injected with 12 mg/kg kainate every 60 min three times. The rate of dead mice to the total mice was higher in zinc-deficient group than in control group 3 days after the last injection of kainate. In the survivals, which exhibited tonic convulsions in both control and zinc-deficient groups, kainate-induced hippocampal cell death was also analyzed by cresyl violet staining. Neuronal loss was more observed in the CA1, CA2 and CA3 pyramidal cell layers of zinc-deficient group than those of the control group. TUNEL-positive cells were significantly more detected in the CA1 and CA3 pyramidal cell layers of zinc-deficient group. These results demonstrate that kainate-induced hippocampal cell death occurs more easily in zinc deficiency. Extracellular zinc concentration detected with ZnAF-2 was significantly decreased in the hippocampal CA3 of zinc-deficient mice, in agreement with the previous data measured by in vivo microdialsysis. Synaptically released zinc may be less involved in kainate-induced hippocampal cell death in zinc deficiency. 相似文献
19.
Effects of zinc on the induction of metallothionein isoforms in hippocampus in stress rats 总被引:1,自引:0,他引:1
Chen WQ Cheng YY Zhao XL Li ST Hou Y Hong Y 《Experimental biology and medicine (Maywood, N.J.)》2006,231(9):1564-1568
Metallothioneins (MTs) are involved in the cellular metabolism of zinc and in cytoprotection against stress factors. Hippocampus plays a specific role in the body's response to stressors. The present study was conducted to evaluate the effects of zinc on the expression of metallothionein isoforms in the hippocampus of stress rats. The animal model of psychologic stress was developed by restraint for 4 weeks. Wistar rats were randomly assigned to 6 groups: control group, zinc-deficient group, zinc-supplemented group, and the corresponding 3 stress groups. Three separate diets of different zinc contents (1.73 ppm, 17.7 ppm, and 41.4 ppm, respectively) were used in this study. Compared with the control group, the stress groups had higher inductions of MTs and MT-1 and MT-3 mRNA in hippocampus. On the one hand, the expressions of MTs and their mRNAs in hippocampus were downregulated in the zinc-deficient group; however, their expressions were evidently enhanced in the stress zinc-deficient group. MT induction in the zinc-supplemented group was increased. Furthermore, the stress zinc-supplemented group had a more significant yield of MTs and their mRNAs. In addition, the levels of plasma cortisol, interleukin-6 (IL-6), IL-1, and nitric oxide (NO) were increased clearly in the zinc-deficient group and the stress groups. The results suggest that zinc deficiency may decrease and zinc supplementation may increase the expressions of MTs and their mRNAs in hippocampus; moreover, stress can increase their expressions dramatically. The impairment of stress on the body may be involved with the nutrition status of zinc, and zinc deficiency can lower the body's adaptability to stress. 相似文献
20.
Wided Fatmi Zine Kechrid Mustafa Nazıroğlu Manuel Flores-Arce 《Biological trace element research》2013,152(2):243-250
Diabetes mellitus is associated to a reduction of antioxidant defenses that leads to oxidative stress and complications in diabetic individuals. The present study was undertaken to investigate the effect of selenium on blood biochemical parameters, antioxidant enzyme activities, and tissue zinc levels in alloxan-induced diabetic rats fed a zinc-deficient diet. The rats were divided into two groups; the first group was fed a zinc-sufficient diet, while the second group was fed a zinc-deficient diet. Half of each group was treated orally with 0.5 mg/kg sodium selenite. Tissue and blood samples were taken from all animals after 28 days of treatment. At the end of the experiment, the body weight gain and food intake of the zinc-deficient diabetic animals were lower than that of zinc-adequate diabetic animals. Inadequate dietary zinc intake increased glucose, lipids, triglycerides, urea, and liver lipid peroxidation levels. In contrast, serum protein, reduced glutathione, plasma zinc and tissue levels were decreased. A zinc-deficient diet led also to an increase in serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and liver glutathione-S-transferase and to a decrease in serum alkaline phosphatase activity and glutathione peroxidase. Selenium treatment ameliorated all the values approximately to their normal levels. In conclusion, selenium supplementation presumably acting as an antioxidant led to an improvement of insulin activity, significantly reducing the severity of zinc deficiency in diabetes. 相似文献