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1.
We investigated the application of fungus Phallus impudicus loaded γ-Fe2O3 nanoparticles as a biosorbent for magnetic solid phase extractions of trace levels of Zn(II) and Cr(III) ions from natural samples before their measurements by inductively coupled plasma optical emission spectrometry. The characterization of magnetized P. impudicus was performed using the scanning electron microscope, the energy dispersive X-ray and Fourier transform infrared spectroscopy. Important experimental factors were investigated. The experimental results fitted well to the Langmuir adsorption model and pseudo-second order kinetic model. Limit of detections of targeted ions by magnetic solid phase extraction method based on use of P. impudicus were found as 10.5 ngL−1 and 12.6 ngL−1 respectively for Cr(III) and Zn(II). The sorption capacities of the biosorbent were 22.8 mgg−1 for Cr(III) and 25.6 mgg−1 for Zn(II). The preconcentration factors were achieved as 100 for both of ions. RSDs for inter- and intraday precisions were found as lower than 2.0% and 2.1% respectively for both of targeted ions. The accuracy of the recommended process was tested by recovery measurements on the certificated reference materials and successfully applied for quantification recoveries of Cr(III) and Zn(II) ions from water and food samples. 相似文献
2.
Summary The developing pigment strand of rice (Oryza sativa L.) was studied by conventional electron microscopy and also by use of thick sections post-fixed with zinc iodide and osmium (ZIO).When the rice caryopsis achieves maximum length, a suberised adcrusting wall layer is laid down over the original primary walls of the pigment strand. Concomitant with suberin deposition a proliferation of tubular endoplasmic reticulum occurs in the cytoplasm giving rise to numerous interconnected vesicles which bear ribosomes. The vesicles in the general cytoplasm retain their ribosomes while those close to the wall become smooth and contain an electron-opaque granular material which is eventually deposited to the outside of the plasmalemma. This granular material may be the precursor(s) from which suberin is polymerised. The suberised wall attains about six times the width of the original primary wall and plasmodesmata, which traverse both primary wall and suberised wall layers, become greatly elongated.Lipid bodies increase in both size and frequency during development, eventually coalescing to form a complete plug across the pigment strand and occluding the symplast of this tissue. The significance of these ultrastructural observations is discussed in relation to the previously demonstrated role of the pigment strand as a translocation pathway for water and assimilates during grain filling.Abbreviations ER
endoplasmic reticulum
- ZIO
zinc iodide-osmium fixation 相似文献
3.
Summary The mechanism of higher grain production of wheat (Triticum aestivum L.) by four tillage methods was explored on a sandy calcareous soil of Sahl-Al Jafara, Libya, during the year 1976–77. Tillage methods increased grain yield and dry matter weight at the boot stage in the order of no-tillage<rotovator=disc plough < subsoiler. Rotovation to 15 cm and disc ploughing to 25 cm depth enhanced grain production mainly by eliminating weed competition. In both the cases, roots penetrated < 25 cm where plough-pan existed.Further yield increases by 50 cm deep subsoiling seems to be mainly explained by N and Cu rise in plants from their marginal to optimum levels and by reduction of Mn deficiency in plant shoots. Penetration of roots beyond the 25 cm plough-pan apparently resulted in higher absorption of these nutrients from leached or native soil supplies. Subsoiling also resulted in greater Zn concentration in plant shoots which, under marginal to deficient conditions, will also increase grain production. 相似文献
4.
Zenon Lukaszewski Ryszard Siwecki Jadwiga Opydo Wlodzimierz Zembrzuski 《Trees - Structure and Function》1993,7(3):169-174
Summary The patterns of radial distribution of copper, lead, zinc and cadmium in two species of poplar, growing under polluted conditions near a copper smelter, were investigated. Populus marilandica is very resistant to such pollution, but P. balsamifera is sensitive. Soils were examined for concentrations of these metals, and only a surface layer of soil was polluted with copper and lead. P. balsamifera absorbed much more cadmium than P. marilandica under the same conditions. P. marilandica shows a pattern of copper radial distribution with significantly increased concentration of the meral in the layers in the middle of the trunk compared to P. balsamifera. Zinc and cadmium have a pattern with increased metal concentration from the bark towards the pith of the tree. In the case of copper and lead the pattern indicates increased concentrations of these metals in the rings adjacent to the pith while the pattern in other parts of the tree remains unconfirmed due to poor precision. Poplar xylem seems to accumulate zinc and cadmium while the content of lead in xylem is much lower than in the adjacent soil.This paper is dedicated to the memory of Professor Stefan Bialobok, Institute of Dendrology, Polish Academy of Sciences in Kornik 相似文献
5.
The purpose of the present study was to determine whether zinc and calcium could interact at the tissue level. In the first
part of the study, adult rats were injected with ZnCl2 dissolved in a physiological saline solution to determine the effects of Zn on Ca levels in various tissues. In the second
part of the study, weaned rats (at day 22 postnatally) were fed a diet supplemented with Zn until day 50 and were then sacrificed.
In both instances, blood, brain, heart, liver, and skeletal muscle were taken and analyzed. In the Zn-injected group, the
brain, heart, and liver showed no interaction between Zn and Ca. The skeletal muscle, in contrast, showed a decrease in Ca
in the homogenate, whereas Zn contents showed a significant increase at the sarcoplasmic reticulum (SR). Likewise, in the
Zn-supplemented group, the Zn content of the SR vesicle of the skeletal muscle showed an increase, whereas Ca content of the
pellet (14,000 g), which contains cell debris, nucleus, mitochondria, and SR vesicles of this group, showed a decrease. Current
findings suggest antagonistic effects between Zn and Ca on this tissue. Zn may play a critical role in cellular function through
the alteration of itnracellular distribution of Ca in skeletal muscle. 相似文献
6.
BackgroundGlial cells such as astrocytes and microglia play an important role in the central nervous system via communication between these glial cells. Activated microglia can exhibit either the inflammatory M1 phenotype or the anti-inflammatory M2 phenotype, which influences astrocytic neuroprotective functions, including engulfment of cell debris. Recently, extracellular zinc has been shown to promote the inflammatory M1 phenotype in microglia through intracellular zinc accumulation and reactive oxygen species (ROS) generation.PurposeHere, we investigated whether the zinc-enhanced inflammatory M1 phenotype of microglia affects the astrocytic engulfing activity.MethodsEngulfing activity was assessed in astrocytes treated with microglial-conditioned medium (MCM) from lipopolysaccharide (LPS)-activated or from ZnCl2-pretreated LPS-activated M1 microglia. The effect of zinc on microglia phenotype was also validated using the zinc chelator N,N,N’,N’-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and the ROS scavenger Trolox.ResultsAlthough treatment of astrocytes with LPS showed no significant effect on the engulfing activity, MCM from LPS-induced M1 microglia increased the beads uptake by astrocytes. This increased uptake activity was suppressed when MCM from LPS-induced M1 microglia pretreated with ZnCl2 was applied to astrocytes, which was further abolished by the intracellular zinc chelator TPEN and the ROS scavenger Trolox. In addition, expression of P2×7 receptors (P2×7R) was increased in astrocytes treated with MCM derived from M1 microglia but not in the M1 microglia pretreated with ZnCl2.ConclusionThese findings suggest that zinc pre-treatment abolishes the ability of LPS-induced M1 microglia to increase the engulfing activity in astrocytes via alteration of astrocytic P2×7R. 相似文献
7.
8.
Margarita Burguera-Pascu Alberto Rodríguez-Archilla Pilar Baca 《Journal of trace elements in medicine and biology》2007,21(2):92-101
The antimicrobial efficacy of zinc (Zn) salts (sulfate and acetate) against Streptococcus mutans (S. mutans) present in the oral cavity was tested in this study. The substantivity of Zn salts was assessed by determining the concentration of Zn in whole, unstimulated saliva and by measuring the magnitude of suppression of salivary S. mutans, 2h after rinsing. The concentration of Zn was measured by atomic absorption spectrometry (AAS) with electrothermal atomization (ET AAS) in saliva sampled before (basal) and 24h after mouth rinsing with different concentrations of Zn (0.1%, 0.5% and 1%) administrated as sulfate and acetate. The estimation of Zn levels in samples collected 30, 60, 90 and 120 min after rinsing was carried out by AAS with flame atomization (FAAS). Immediately after rinsing, the concentration of Zn in saliva sharply increased with respect to the baseline values (0.055+/-0.017 mg/L), followed by a sustained decrease, probably due to clearance of salivary flow or swallowing during sampling. A significant reduction (>87%) in the total mean S. mutans counts was found 2h after rinsing either with sulfate or acetate solutions, as evidence of the high substantivity and effectiveness of the Zn salts tested. A statistically significant inverse relationship (p<0.001 and the Pearson correlation coefficients between -34% and -50%) was found between Zn levels and the respective pH values measured in the samples collected 60 and 120 min after rinsing, sustaining the theory of bacterial glycolysis inhibition. 相似文献
9.
Z. Zachwieja J. Chlopicka M. Schlegel-Zawadzka P. Zagrodzki J. Wypchlo M. Krośniak 《Biological trace element research》1995,47(1-3):141-145
The zinc content in the hair of 654 children living in various rural and industrial areas in southern Poland was assayed by
means of the atomic absorption spectrometry, following the dry digestion procedure. The hair of girls exhibited statistically
significant higher level of Zn than the boys’ hair, although in the site of extremal Zn contamination, the inverse relation
was found. 相似文献
10.
Autophagy is a conserved catabolic process that plays an important role in cellular homeostasis. The study of the interplay between autophagy and zinc has gained interest over the last years. Multiple studies have indicated that zinc stimulates autophagy and is critical for basal and induced autophagy in mammalian cells. Conversely, autophagy is induced by zinc starvation in yeast. There are no studies analyzing the role of zinc in either Microautophagy or Chaperone-Mediated-Autophagy. The mechanisms by which zinc modulates autophagy are still poorly understood. Studies examining loss of function of genes involved in cellular zinc homeostasis have provided novel insights into the role of zinc in autophagy. Autophagy may help cells adapt to changes in zinc availability in medium by controlling zinc mobilization, recycling, and secretion. Zinc is a key player in toxic and protective autophagy. 相似文献