OBJECTIVETo investigate the characteristics of Zn2+ biosorption and the release of cations during the process of Zn2+ biosorption by intact cells of Saccharomyces cerevisiae.

METHODSThe batch adsorption test was used to study the biosorption equilibrium and isotherm. Zn2+ concentration was measured with atomic adsorption spectrophotometer (AAS) AAS 6 Vario.

RESULTSWhen the initial concentration of Zn2+ ranged between 0.08 and 0.8 mmol/L, the initial pH was natural (about 5.65), the sorbent concentration was about 1 g/L and the capacity of Zn2+ biosorption was from 74.8 to 654.8 micromol/g. The pH value increased by 0.55-1.28 and the intracellular cations (K+, Mg2+, Na+, Ca2+) of the cells were released during the process of Zn2+ biosorption.

CONCLUSIONIon exchange was one of the mechanisms for Zn2+ biosorption. The biomass of Saccharomyces cerevisiae is a potential biosorbent for the removal of Zn2+ from aqueous solution. More work needs to be done before putting it into practical application.

Hydrogen-Ion Concentration ; Saccharomyces cerevisiae ; metabolism ; Spectrophotometry, Atomic ; Zinc ; metabolism

Covalently anchoring of a ligand/metal via polar amino acid side chain(s) is often observed in metalloenzyme, while the substitutability of metal-binding sites remains elusive. In this study, we utilized a zinc-dependent alcohol dehydrogenase from Thermoanaerobacter brockii (TbSADH) as a model enzyme, analyzed the sequence conservation of the three residues Cys37, His59, and Asp150 that bind the zinc ion, and constructed the mutant library. After experimental validation, three out of 224 clones, which showed comparative conversion and ee values as the wild-type enzyme in the asymmetric reduction of the model substrate tetrahydrofuran-3-one, were screened out. The results reveal that the metal-binding sites in TbSADH are substitutable without tradeoff in activity and stereoselectivity, which lay a foundation for designing ADH-catalyzed new reactions via metal ion replacement.
Alcohol Dehydrogenase/metabolism* ; Catalytic Domain ; Ligands ; Protein Domains ; Zinc/metabolism*

In the present research, molecular simulation and quantum chemistry calculations were combined to investigate the thermal stability of three kinds of insulin aggregations and the effect of Zn (II) ion coordination on these aggregations. The results of molecular simulation indicated that the three insulin dimers in the same sphere closed hexamer had synergistic stability. It is the synergistic stability that enhances the structural and thermal stability of insulin, preserves its bioactivity during production, storage, and delivery of insulin formulations, and prolongs its halflife in human bodies. According to the results of quantum chemistry calculations, each Zn (II)-N (Im-insulin) bond energy can reach 73.610 kJ/mol for insulin hexamer and 79.907 kJ/mol for insulin tetramer. However, the results of Gibbs free energy changes still indicats that the coordination of zinc (II) ions is unfavorable for the formation of insulin hexamer, because the standard Gibbs free energy change of the coordinate reaction of zinc (II) ions associated with the formatting insulin hexamer is positive and increased.
Insulin ; chemistry ; metabolism ; Molecular Dynamics Simulation ; Protein Stability ; Zinc ; chemistry

Zn²⁺ is required for the activity of many mitochondrial proteins, which regulate mitochondrial dynamics, apoptosis and mitophagy. However, it is not understood how the proper mitochondrial Zn²⁺ level is achieved to maintain mitochondrial homeostasis. Using Caenorhabditis elegans, we reveal here that a pair of mitochondrion-localized transporters controls the mitochondrial level of Zn²⁺. We demonstrate that SLC-30A9/ZnT9 is a mitochondrial Zn²⁺ exporter. Loss of SLC-30A9 leads to mitochondrial Zn²⁺ accumulation, which damages mitochondria, impairs animal development and shortens the life span. We further identify SLC-25A25/SCaMC-2 as an important regulator of mitochondrial Zn²⁺ import. Loss of SLC-25A25 suppresses the abnormal mitochondrial Zn²⁺ accumulation and defective mitochondrial structure and functions caused by loss of SLC-30A9. Moreover, we reveal that the endoplasmic reticulum contains the Zn²⁺ pool from which mitochondrial Zn²⁺ is imported. These findings establish the molecular basis for controlling the correct mitochondrial Zn²⁺ levels for normal mitochondrial structure and functions.
Animals ; Caenorhabditis elegans/metabolism* ; Cation Transport Proteins/genetics* ; Homeostasis ; Mitochondria/metabolism* ; Zinc/metabolism*

OBJECTIVETo explore the effects of micro-elements fertilizers on the quality and yields of Artemisia annua.

METHODField experiments were conducted according to the method of random blocks design. After the harvest the yield was calculated and the content of artemisinin was determined.

RESULTBy applying 0.1%-0.5% Mn and 0.1%-0.5% Zn the dried leaf output and artemisinin content were increased.

CONCLUSIONThe suitable ranges of Mn and Zn can increased the yield and artemisinin content of A. annua.

Artemisia annua ; drug effects ; metabolism ; Artemisinins ; metabolism ; Boron ; pharmacology ; Manganese ; pharmacology ; Zinc ; pharmacology

AIMTo make approach to the relationship between the changes of free zinc and ischemic neuronal damage in hippocampus after forebrain ischemia/reperfusion.

METHODSThe models of forebrain ischemia/reperfusion were established in rats. The contents of free Zn2+ were measured by TSQ fluorescence method. The Zn2+ chelator (CaEDTA) was injected into lateral ventricles in order to evaluate the effect of free Zn2+ on ischemic neuronal damage.

RESULTS(1) Zn2+ fluorescence in the hilus of dentate gyrus, CA3 region and the stratum radiatum and stratum oriens of CA1 decreased slightly at forty-eight hours after reperfusion. From seventy-two hours to ninety-six hour after reperfusion, the decreased fluorescence gradually returned to the normal level, but some fluorescence dots were found in pyramidal neurons of CA1 and the hilus of dentate gyrus. Seven days after reperfusion, all the changes of the fluorescence almost recovered. (2) The cell membrane-impermeable Zn2+ chelator CaEDTA could reduce the intracellular concentration of free Zn2+ and reduced neuronal damage after forebrain ischemia/reperfusion.

CONCLUSION(1) The synaptic vesicle Zn2+ released and then translocated into postsynaptic neurons after forebrain ischemia/reperfusion and played a role in ischemic neuronal damage. (2) The cell membrane-impermeable chelator CaEDTA could provide neuroprotection.

Animals ; Brain Ischemia ; metabolism ; pathology ; Hippocampus ; pathology ; Male ; Neurons ; metabolism ; Rats ; Rats, Wistar ; Reperfusion Injury ; metabolism ; pathology ; Zinc ; metabolism

The effect of dexamethasone (10(-5)M) and epinephrine (10(-6)M) on the biosynthesis of metallothionein (MT) in the perfused rat liver was investigated. MT synthesis was determined by measuring the incorporation of 14C-L-aspartic acid into liver MT fraction after the perfusion for five hours of isolated liver by artificial blood containing 14C-L-U-aspartic acid (0.2uci) with dexamethasone or epinephrine. MT was isolated by Sephadex G-75 column chromatography and DEAE Sephadex column chromatography. Incorporation of radioactive 14C into the MT fraction of perfused liver cytosol (9.0grams of liver) from dexamethasone treated, epinephrine treated and control groups were, respective1y, 0.72, 0.34 and 0.33% of total radioactivity infused. Total protein content in the MT fraction of liver perfused with dexamethasone and epinephrine were 0.80, 0.64mg/g liver compared to 0.52mg/g liver in the control. MT, a protein having a high content of cystein and metals is synthesized in the perfused rat liver and its induction is stimulated by dexamethasone, while epinephrine increased the accumulation of Zn in the MT fraction of the perfused rat liver. The present experiment confirms that MT synthesis and degradation are somewhat regulated by glucocorticoid hormone and epinephrine.
Animal ; Dexamethasone/pharmacology* ; Epinephrine/pharmacology* ; Female ; In Vitro ; Liver/drug effects ; Liver/metabolism* ; Metalloproteins/metabolism* ; Metallothionein/metabolism* ; Perfusion ; Rats ; Zinc/metabolism

OBJECTIVETo study the mechanism of microelement including Cu and Zn on the accumulation of three danshinones in Salviae miltiorrhizae root and build a theory basis for its good quality and high yield.

METHODSand culture experiments were conducted to study the effect of Cu and Zn on the accumulation of three danshinones and oxidase including peroxidase and polyphenol oxidase activity in the plant root. The correlation between available Cu and Zn contents in matrix and oxidase activity in the plant root and, the correlation between available Cu and Zn contents in matrix and contents of tanshinones in the root were discussed.

RESULTContents of danshinones in the root increased with the increasing of Cu and Zn concentration. Dynamic monitoring on contents of dan-shinones of the plant roots growing in the pots with different Cu and Zn concentration in the whole growing season showed that the contents of danshinones for 60 days were the lowest, for 120 days the highest and then dropped for 150 days. In addition, among available Cu and Zn contents of matrix, oxidase including peroxidase and polyphenol oxidase activity and contents of tanshinones in the root,the correlation between two factors were significant difference (P < 0.05 or P < 0.01).

CONCLUSIONThe mechanism of Cu and Zn on the accumulation of danshinones may be that Cu and Zn improve the activity of peroxidase and polyphenol oxidase, which promote transformation of phenolic compounds to terpenes and therefore to increase contents of danshinones.

Catechol Oxidase ; metabolism ; Copper ; metabolism ; Diterpenes, Abietane ; Drugs, Chinese Herbal ; analysis ; metabolism ; Peroxidase ; metabolism ; Phenanthrenes ; metabolism ; Plant Proteins ; metabolism ; Salvia miltiorrhiza ; enzymology ; metabolism ; Zinc ; metabolism

This research use "3414" fertilizer effect experiments to handle zinc, boron and molybdenum trace element fertilizer, determined the dry matter accumulation and content of saikosaponion a and d, to investigate the different ratio of zinc, boron and molybdenum on yield and saikosaponin a, saikosaponin d contents of Bupleurum chinense. Found The suitable ratio of zinc, boron and molybdenum play an active role on dry matter accumulation and distribution, the treatment Zn2B2Mo3 is the best one to promote the dry matter accumulation and transfer to the underground part; in a certain range, only use zinc or molybdenum can promote the yield of B. chinense, the yield of treatment Zn2B2Mo1 is the highest one. According to the results of regression analysis: in accordance with Zn 48.45 g x hm(-2), B 355.05 g x hm(-2), Mo 86.40 g x hm(-2), can obtain the yield with 3313.05 kg x hm(-2); the treatment Zn2BMo2 is most effective to promote the total saikosaponin a and d accumulated, according to the results of regression analysis: in accordance with Zn 36.15 g x hm(-2), B 343.05 g x hm(-2), Mo 106.35 g x hm(-2), the content of total saikosaponin a and d can reach 1.23%. This research first discovered the suitable ratio of zinc, boron and molybdenum can promote the yield and saikosaponin a, saikosaponin d contents on B. chinense.
Boron ; metabolism ; Bupleurum ; metabolism ; Fertilizers ; Molybdenum ; metabolism ; Oleanolic Acid ; analogs & derivatives ; metabolism ; Plant Roots ; metabolism ; Saponins ; metabolism ; Trace Elements ; metabolism ; Zinc ; metabolism

Animals ; Calcium ; metabolism ; Copper ; metabolism ; Environmental Exposure ; prevention & control ; Erythrocytes ; metabolism ; Hazardous Substances ; metabolism ; poisoning ; Humans ; Mercury ; metabolism ; Metallothionein ; biosynthesis ; genetics ; metabolism ; Zinc ; metabolism