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PubMed1996

The autometallographic zinc-sulphide method. A new approach involving in vivo creation of nanometer-sized zinc sulphide crystal lattices in zinc-enriched synaptic and secretory vesicles.

A new version of Timm's sulphide silver method involving in vivo binding of zinc ions in zinc enriched terminals is presented. By injecting sodium sulphide into the vena cava of deeply anaesthetized animals, it is possible to bind chemically the vesicular zinc, i.e. chelatable zinc (zinc ions), in secretory and synaptic vesicles, in the form of zinc sulphide crystal lattices. Four minutes after the intravenous injection the animal is perfused transcardially with a phosphate-buffered solution of glutaraldehyde, glutaraldehyde and formaldehyde, or with a saline solution. The nanometer-sized catalytic crystals can then be silver-amplified in cryostat and vibratome sections by exposure to an autometallographic developer. It is demonstrated that contemporaneously with silver enhancement, the zinc sulphide crystals are transformed to the corresponding silver sulphide crystals. For ultrastructural studies, autometallographic development of vibratome sections is recommended. From these sections tissue blocks are cut from the areas of interest, blockstained with osmium tetroxide and embedded in Epon. This approach results in a zinc-specific autometallographic staining of the sections of a hitherto unseen, high technical quality.

Animals↗
PubMed1997

The tyrosine photophysics of a primase-derived peptide are sensitive to the peptide's zinc-bound state: proof that the bacterial primase hypothetical zinc finger sequence binds zinc.

A 35-amino acid peptide corresponding to the putative "zinc finger" sequence of primase was prepared to study its zinc binding properties. When zinc was added to the peptide, it was found that the fluorescence quantum yield of the single tyrosine increased by 46% and the average lifetime by 34%. The binding stoichiometry was one zinc per peptide. Below pH 6.0 and above pH 8.5, the zinc-peptide binding affinity was less than 1 microM and could be accurately determined. Interpolation from those binding constants suggested that the affinity at pH 7.5 was between 10 and 100 nM. The absorption spectrum of the cobalt(II)-peptide complex was consistent with tetrahedral metal coordination by three sulfur and one imidazole nitrogen ligands. The peptide affinity for cobalt was less than for zinc, indicating metal specificity. Analysis of the fluorescence intensity pH profile, circular dichroism spectra, the effect of extrinsic quenchers indicated that at neutral pH (1) the free peptide up into a structure to place the tyrosine in an environment protected from solvent, (2) the peptide bound zinc via its three cysteines and one of its histidines resulting in little change to the polypeptide secondary structure or to the tyrosine solvent accessibility, and (3) when the peptide bound zinc, it bound directly to or caused the immobilization of the groups that had been intramolecularly collisionally quenching the tyrosine which resulted in the observed increases in tyrosine quantum yield and lifetime.

DNA Primase↗
PubMed2005

Normal growth rate in rats is recovered after a period of zinc deficiency by restoration of zinc supply by means of a zinc-fortified Petit Suisse cheese.

Fortification of a Petit Suisse cheese with zinc sulfate and zinc gluconate stabilized with glycine was used as a tool to overcome zinc-deficiency effects on total-body growth and skeletal growth. Animals were divided in 4 groups of 10 rats: basal (B), control (C), depletion-repletion 1 (DR1), and depletion-repletion 2 (DR2). These four groups were fed with four diets: basal (2 ppm Zn), control (30 ppm Zn), DR1, and DR2; they received a basal diet for 14 d and a control diet for the other 14 d of the experiment, using zinc sulfate for DR1 and zinc gluconate stabilized with glycine for DR2. After 28 d of the experiment, total-body weight and weight gain of the control and DR1 and DR2 animals were not statistically different (p<0.05), Femur weight and femur zinc content of DR1 and DR2 did not achieve the values of control animals (p<0.05), but they were higher than that of basal animals. Our results show that restoration of dietary zinc levels by means of food fortification normalized weight gain, as an indicator of total-body growth, and presented a trend to normalize bone weight, as a marker of skeletal growth, in young rats and independently of the zinc source used.

Animals↗
PubMed2005

Zinc-specific autometallographic in vivo selenium methods: tracing of zinc-enriched (ZEN) terminals, ZEN pathways, and pools of zinc ions in a multitude of other ZEN cells.

In vivo-applied sodium selenide or sodium selenite causes the appearance of zinc-selenium nanocrystals in places where free or loosely bound zinc ions are present. These nanocrystals can in turn be silver enhanced by autometallographic (AMG) development. The selenium method was introduced in 1982 as a tool for zinc-ion tracing, e.g., in vesicular compartments such as synaptic vesicles of zinc-enriched (ZEN) terminals in the central nervous system, and for visualization of zinc ions in ZEN secretory vesicles of, e.g., somatotrophic cells in the pituitary, zymogene granules in pancreatic acinar cells, beta-cells of the islets of Langerhans, Paneth cells of the crypts of Lieberkühn, secretory cells of the tubuloacinar glands of prostate, epithelium of parts of ductus epididymidis, and osteoblasts. If sodium selenide/selenite is injected into brain, spinal cord, spinal nerves containing sympathetic axons, or intraperitoneally, retrograde axonal transport of zinc-selenium nanocrystals takes place in ZEN neurons, resulting in accumulation of zinc-selenium nanocrystals in lysosomes of the neuronal somata. The technique is, therefore, also a highly specific tool for tracing ZEN pathways. The present review includes an update of the 1982 paper and presents evidence that only zinc ions are traced with the AMG selenium techniques if the protocols are followed to the letter.

Animals↗
PubMed1988

The effect of burn injury and zinc nutriture on fecal endogenous zinc, tissue zinc distribution, and T-lymphocyte subset distribution using a murine model.

The interrelationship among burn injury, zinc metabolism, and circulating T-lymphocyte distribution was studied using a rat model. Sixty Sprague-Dawley male rats were fed a zinc-deficient (less than 0.5 ppm) semipurified diet and given daily subcutaneous injections of 1 mg Zn/kg body wt for 14 days. On Day 15, 24 of the rats were subjected to a full-thickness dorsal scald injury of 30% of the total body surface. Half of the burned rats were continued on the zinc supplementation (BS) while the other half were maintained on the zinc-deficient (BD) regimen by injecting physiological saline. Feces and urine were collected for 10 days postburn and subsequently analyzed for zinc content. On Day 10 postburn all the rats were sacrificed. Zinc bound to cytosol proteins in hepatic and intestinal mucosal tissue was determined by gel column chromatography procedures and T-lymphocyte subset distributions were determined by flow cytometry. No significant difference (P less than 0.05) in total endogenous zinc excretion was seen among treatment groups. A dramatic increase was seen in zinc bound to a 12,000 mol wt protein in hepatic tissue from the BS group only. The only significant (P less than 0.05) change in T-lymphocyte populations was an increase in T-suppressor cells in the BD group.

Animals↗
PubMed1993

The effect of zinc in the form of erythromycin-zinc complex (Zineryt lotion) and zinc acetate on metallothionein expression and distribution in hamster skin.

The occurrence of zinc-induced synthesis of metallothionein in skin after topical application of the anti-acne drug Zineryt lotion was investigated in hamster ears. The dinitrophenyl hapten-sandwich immunohistochemical method involving a monoclonal anti-metallothionein (MT) antibody (E9) was used to detect and localize zinc-binding MT in the 'treated' and untreated hamster skin. Atomic absorption spectrophotometry and dithizone histochemistry indicated that zinc penetrated the skin more readily, and accumulated more efficiently within the sebaceous glands, when applied to the skin surface as the organo-zinc complex, rather than as the inorganic zinc salt. MT and zinc had similar distributions in hamster skin exposed to the metal. Thus, MT immunoreactivity was especially intense in the sebaceous glands of Zineryt lotion-treated skin, with evidence of nuclear distribution in some cells. Zinc delivered to the sebaceous glands, and released from the organo-complex under the prevailing aqueous conditions, certainly induced MT synthesis; the cysteine-rich protein may protect the pilosebaceous units during the inflammatory phase of acne by scavenging generated oxyradical species.

Acetates↗
PubMed1982

Zinc and zinc ligands in human seminal plasma. III. The principal low molecular weight zinc ligand in prostatic secretion and seminal plasma.

The principal zinc binding component in human prostatic fluid and seminal plasma has been found to bind zinc reversible and to be of low molecular weight. Treatment of this zinc containing complex (LMW-Zn) with trypsin and pronase or acid hydrolysis failed to alter its zinc binding properties or gel chromatographic characteristics. Removal of citrate with a combination of citrate lyase, malate dehydrogenase and lactate dehydrogenase did, however, completely abolish its ability to bind zinc. Spectrographical scanning of LMW-Zn preparations obtained by gel chromatography of prostatic fluid or seminal plasma on a Sephadex G-25 column gave identical absorption curves with those obtained by scanning of a zinc-citrate solution. Application of the same analysis to LMW-Zn of human breast milk yielded similar results. It is concluded that citrate is the major low molecular weight zinc ligand in prostatic fluid, seminal plasma and breast milk.

Amino Acids↗
PubMed1998

Influence of dietary lysine on the utilization of zinc from zinc sulfate and a zinc-lysine complex by young pigs.

We conducted two trials (n = 144 and 96) to evaluate the response of feeding either ZnSO4 x H2O or a zinc-lysine complex (ZnLys) in combination with various lysine levels on growth performance, liver, kidney, and 10th rib Zn concentration, serum Zn humoral immune response and absorption of Zn (chromic oxide method) of young pigs. The following treatments were started after a 7-d postweaning adjustment during which all pigs were fed a common diet adequate in zinc. Diets were as follows: 1) basal 1 (B1), .8% dietary lysine without added Zn (basal contained 32 ppm Zn); 2) B1 plus 100 ppm Zn from ZnSO4; 3) B1 plus 100 ppm Zn from ZnLys, 4) basal 2 (B2), 1.1% lysine without added Zn; 5) B2 plus 100 ppm Zn from ZnSO4; 6) B2 plus 100 ppm Zn from ZnLys. In Trial 1 only, 100 ppm Zn from ZnSO4 (diet 7) or ZnLys (diet 8) was added to a .95% lysine basal diet. The basal 20% CP diet contained 9.0% corn gluten meal to lower the total lysine level. Within lysine level, all diets were made isolysinic by using crystalline lysine. Zinc sulfate, ZnLys, or lysine replaced dextrose in the basal diet. After 4 wk on test, one barrow in each pen was killed; liver, kidney, left 10th rib, and contents of the stomach, small intestine, and lower colon were removed for Zn analyses. Performance (ADG and ADFI) was only improved (P < .05) in one of the two trials when either zinc source was added to the basal diets, but performance was higher (P < .01) for pigs fed 1.1% lysine diets compared with .8% lysine diets in both trials. Serum Zn concentrations were lower (P < .001) for pigs fed both dietary lysine basal diets without added Zn. The humoral response to sheep red blood cells and ovalbumin was not influenced (P > .20) by lysine level, or Zn level and source. Pigs fed diets without added Zn had lower (P < .001) liver, kidney, and rib Zn concentrations than pigs fed diets with added Zn regardless of Zn source. Dietary lysine did not influence liver Zn, but kidney (P < .01) and rib (P < .001) Zn concentrations were lower for pigs fed the higher lysine level. Digestibility coefficients of Zn were lower in the stomach for pigs fed diets without added Zn, similar among Zn levels and sources in the small intestine, and higher in the lower colon for pigs fed the basal diets without added Zn. Lysine level and Zn source did not influence Zn absorption. The ZnSO4 and a zinc lysine complex seemed to be equally effective in promoting growth performance, zinc absorption, and tissue stores of young pigs when diets contained deficient, adequate, or slightly more than adequate levels of lysine.

Animal Nutritional Physiological Phenomena↗
PubMed2002

Effects of cadmium and zinc on solar-simulated light-irradiated cells: potential role of zinc-metallothionein in zinc-induced genoprotection.

Zinc is an essential oligoelement for cell growth and cell survival and has been demonstrated to protect cells from oxidative stress induced by UVA or from genotoxic stress due to UVB. In a recent work we demonstrated that the antioxidant role of zinc could be related to its ability to induce metallothioneins (MTs). In this study we identified the mechanism of zinc protection against solar-simulated light (SSL) injury. Cultured human keratinocytes (HaCaT) were used to examine MTs expression and localization in response to solar-simulated radiation. We found translocation to the nucleus, with overexpression of MTs in irradiated cells, a novel observation. The genoprotective effect of zinc was dependent on time and protein synthesis. DNA damage was significantly decreased after 48 h of ZnCl(2) (100 microM) treatment and is inhibited by actinomycin D. ZnCl(2) treatment (100 microM) led to an intense induction, redistribution, and accumulation of MT in the nucleus of irradiated cells. MT expression correlated with the time period of ZnCl(2) treatment. CdCl(2), a potent MT inducer, did not show any genoprotection, although the MTs were expressed in the nucleus. Overall our findings demonstrate that MTs could be a good candidate for explaining the genoprotection mediated by zinc on irradiated cells.

Cadmium↗
PubMed1994

Size of the zinc pools that exchange rapidly with plasma zinc in humans: alternative techniques for measuring and relation to dietary zinc intake.

A relatively simple technique was used to estimate the size of the combined pools of zinc with which plasma zinc exchanges within 2 d (EZP). EZP size was determined from the amount of isotope introduced into the plasma and the coefficient of the simple exponential decay function fitting enrichment data between d 3 and 9 after isotope administration. Using data from 11 healthy adults, comparisons were made of EZP size estimations using oral and intravenous isotopes (r = 0.93 using urine) and urine and plasma enrichment (r = 0.85 for intravenous). EZP size estimations from urine and plasma enrichment following intravenous isotope administration were 2.35 +/- 0.84 and 2.83 +/- 0.86 mmol, respectively (mean +/- SD, P < 0.01). EZP size correlated with habitual dietary zinc intake (partial r = 0.74, P < 0.02). Cumulative declines in EZP size in two healthy adults after 3 wk of consuming a moderately zinc-restricted diet followed by 1 wk of severe zinc restriction were 26 and 32%. These results indicated that EZP size is dependent on dietary intake. We conclude that this technique is adequate to demonstrate EZP differences that are of nutritional and physiological interest. EZP size estimates can be obtained using orally or intravenously administered isotope and using plasma or urine enrichment data.

Administration, Oral↗
PubMed2003

Role of zinc in eukaryotic cells, zinc transporters and zinc-containing proteins. Review article.

As a catalytic and/or structural cofactor for countless of zinc-dependent enzymes and proteins, zinc is an essential element for all organisms. This review summarizes the basics of human zinc physiology and biochemistry. The role of zinc in the regulation of gene expression and cellular signal transmission is described in more details. The present explosive growth of new knowledge about various biological roles of zinc will undoubtedly lead to the future development of new powerful drugs and to treatment of many diseases including cancer.

Animals↗
PubMed2004

Di-mu-sulfito-bis[(4,4'-dimethyl-2,2'-bipyridine)zinc(II)] dihydrate and poly[[aqua(1,10-phenanthroline)zinc(II)]-mu3-sulfito-zinc(II)-mu3-sulfito].

Two different zinc sulfite compounds have been prepared through the decomposition of pyrosulfite-dithionite ions in aqueous solution, viz. a dimeric complex, di-mu-sulfito-kappa3O,O':O'';kappa3O:O',O''-bis[(4,4'-dimethyl-2,2'-bipyridine-kappa2N,N')zinc(II)] dihydrate, [Zn2(SO3)2(C12H12N2)2].2H2O, (I), which was solved and refined from a twinned sample, and an extended polymer, poly[[aqua(1,10-phenanthroline-kappa2N,N')zinc(II)]-mu3-sulfito-kappa2O:O':O''-zinc(II)-mu3-sulfito-kappa3O:O:O'], [Zn2(SO3)2)(C12H10N2)(H2O)]n, (II). In (I), the dinuclear Zn(II) complex has a center of symmetry. The cation is five-coordinate in a square-pyramidal arrangement, the anion fulfilling a bridging chelating role. Compound (II) comprises two different zinc units, one being five-coordinate (square pyramidal) and the other four-coordinate (trigonal pyramidal), and two independent sulfite groups with different binding modes to the cationic centers.

Journal Article↗
PubMed1991

A high-performance liquid chromatographic assay for phenylmercuric nitrate in the presence of zinc ions and its application to an assessment of the stability of phenylmercuric nitrate in zinc sulphate and zinc sulphate and adrenaline eye drops.

A high-performance liquid chromatographic assay for phenylmercuric nitrate in the presence of zinc ions has been developed. Application of the assay to zinc sulphate and zinc sulphate and adrenaline drops before and after autoclaving demonstrates that the phenylmercuric nitrate is chemically degraded in the zinc sulphate and adrenaline drops.

Chromatography, High Pressure Liquid↗
PubMed2005

[Moscow schoolchildren zinc status: correction of zinc insufficiency by organic zinc compounds].

The paper presents the results of study of zinc hair content in 43 Moscow schoolchildren, aged 9-11 years of both sex (May 2003 to December 2003). Significant drop of zinc hair content was established in 67% of schoolchildren. It was shown that the organic form of zinc enchanted zinc hair content. The findings will be used to implement preventive and health-promoting measures among schoolchildren.

Child↗
PubMed1999

Effect of dietary zinc content and sources on the growth, body zinc deposition and retention, zinc excretion and immune response in chickens.

1. In areas of intensive animal production heavy metals such as zinc (Zn), which is present at high concentrations in poultry excreta in relation to plant requirements, may be at the origin of soil phytotoxicity This study was conducted in order to determine the effect of decreasing dietary Zn content on growth, plasma, tibia and whole body Zn concentrations, immune function, enzyme activity, Zn body retention and Zn concentration in excreta in broilers. 2. Two experiments were carried out using 160 and 80 1-day-old chicks. Broilers received diets with increased Zn contents of 20 to 190 mg/kg. In experiment 1, two sources of zinc methionine were compared to zinc sulphate. 3. A dietary Zn concentration of 45 mg/kg was sufficient to obtain normal broiler performance at 21 d of age. 4. Tibia and plasma Zn concentrations increased linearly with Zn dietary content and reached a plateau at 75 mg/kg, whereas the whole body Zn was saturated when the dietary Zn content was 90 mg/kg. 5. Antibody titres in response to SRBC injection and plasma alkaline phosphatase activity were not affected by dietary zinc concentration. 6. When the dietary Zn content was decreased from 190 to 65 mg/kg, body Zn retention was increased from 8% to 20% and Zn concentration in broiler manure was reduced by 75%. 7. Zn sources had no effect on the parameters measured in this study. 8. A nutritional approach, that is by lowering dietary Zn supplementation may reduce the risks of phytotoxicity in the soil resulting from excessive Zn concentration in manure.

Animal Feed↗