Excess Zinc Research Articles

COMPARATIVE ANALYSIS OF THE EFFECT OF ZINC EXCESS ON THE SHOOT GROWTH OFSINAPIS ALBA AND BRASSICA JUNCEA

The effect of zinc excess on shoot growth of white mustard ( Sinapisalba ) andsareptskaya mustard ( Brassicajuncea ) was studied. Nowadays, supposed that B.juncea is a zinc hyperaccumulator – accumulating its high concentrations in the aboveground organs. In contrast, S.alba belongs to the “excluders” and accumulate the zinc mostly in the roots. It is known, that both species are able to grow on zinc-contaminated soils, but too less known about their metal tolerance. The data about their physiological reactions to excess metal influence are contradictory.In a laboratory experiment, the effect of zinc at concentration of 5 (control), 25, 50, 100, 150 and 200 mg/kg of substrate on a shoot growth parameters in S.alba cv. Radugaand B.juncea cv. Slavanka was studied. Our studies showed, that the effect of zinc on shoot growth mostly depends on the zinc concentration in the substrate as well as the plant species. Thus, zinc at concentration of 25 and 50 mg/kg had a stimulating effect on the growth of shoots of S.alba and only higher concentration of the zinc (100-200 mg/kg) led to decrease in the studied parameters. In B.juncea, even at a metal concentration of 50 mg/kg decrease in shoot height and leaf area. In concentration dependent matter the negative effect was observed. We supposed the the stronger negative effect of zinc at the studied concentrations on the shoot growth of B. juncea as a hyperaccumulator compared to S.alba is associated with a higher content of the metal in its aboveground part. Our results demonstrate the possibility of using studied varieties of S.alba and B. juncea in phytoremediation of zinc contaminated soils.

Association of Zinc with Anemia.

Zinc is an essential trace element, and anemia is the most common blood disorder. The association of zinc with anemia may be divided into three major forms: (1) zinc deficiency contributing to anemia, (2) excess intake of zinc leading to anemia, and (3) anemia leading to abnormal blood-zinc levels in the body. In most cases, zinc deficiency coexists with iron deficiency, especially in pregnant women and preschool-age children. To a lesser extent, zinc deficiency may cooperate with other factors to lead to anemia. It seems that zinc deficiency alone does not result in anemia and that it may need to cooperate with other factors to lead to anemia. Excess intake of zinc is rare. However, excess intake of zinc interferes with the uptake of copper and results in copper deficiency that leads to anemia. Animal model studies indicate that in anemia, zinc is redistributed from plasma and bones to the bone marrow to produce new red blood cells. Inadequate zinc status (zinc deficiency or excess) could have effects on anemia; at the same time, anemia could render abnormal zinc status in the body. In handling anemia, zinc status needs to be observed carefully, and supplementation with zinc may have preventive and curative effects.

Biogeochemical specificity in the Forest-Steppe zone of the country

Living organisms need all chemical elements in trace amounts, but exceeding their regulatory concentrations can have a toxic effect. The toxicity of heavy metals is due to their ability to accumulate in living organisms, to be included in the metabolic cycle and to form highly toxic organometallic compounds. Therefore, the article analyzes the distribution of chemical elements, in particular heavy metals, in the soil and plants of the Forest-Steppe zone. It should be remembered that the influence of deficiency and excess of zinc and copper can cause endemic disorders in plant organisms. Winter wheat plants affected by fusarium root rot viruses and powdery mildew were found in research farms. The distribution and development of diseases in the conditions of the Forest-Steppe of Ukraine was studied. Diagnostic signs of diseases and features of their causative agents are also clarified.

Effect of zinc ion on synthesis of chromium-containing spinel from wastewater and insight into the synthesis mechanism

Stable spinel can be synthesized in chromium-containing wastewater by ferrite process, which can not only realize the purification of chromium-containing wastewater, but also make chromium resource in the wastewater recycle. However, zinc ion often exists in the chromium-containing wastewater, and easily enters the spinel structure when the wastewater is treated by the ferrite process. Therefore, the effect of zinc ion on the synthesis of chromium-containing spinel from the wastewater was investigated, and the synthesis mechanisms was revealed. The quality of the filtrate, stability and magnetic properties of products synthesized at different initial concentrations of zinc ion were examined, and the results verified that moderate zinc ion enhanced the stability of chromium and magnetic properties of synthetic products, but excessive zinc ion reduced the quality of the filtrate. The synthetic path of products was illustrated by examining the stability and crystal evolution of synthetic product, monitoring the potential and pH, testing the dissolved oxygen, and analyzing the contents of metal ions in the filtrate. The synthesis mechanism was further confirmed by SEM-EDS and mössbauer spectra, and the results demonstrated that the gained solid products were mainly composed of goethite and spinel. It was deduced that the molecular formula of synthetic spinel wasFe3.243+(Fex2+⋅Fe2-x3+⋅Cry3+)O1.5y-0.5x+7.86 in the absence of zinc ion. However, the molecular formula of synthetic spinel was (Zn0.52+⋅Fe2.743+)(Fex2+⋅Fe2-x3+⋅Cry3+)O1.5y-0.5x+7.61 in the presence of zinc ion. The study laid a theoretical foundation for the industrial application of ferrite process in the chromium-containing wastewater.

1-Phenyl-3-tosyl-1H-pyrrole

1-Phenyl-3-tosyl-1H-pyrrole was prepared, in moderate yield, by the electrophilic aromatic substitution of 1-phenyl-1H-pyrrole with tosyl chloride in the presence of excess zinc oxide under solvent-free conditions. A minor product was its isomer, 1-phenyl-2-tosyl-1H-pyrrole.

Zinc Carboxylate Surface Passivation for Enhanced Optical Properties of In(Zn)P Colloidal Quantum Dots.

Indium phosphide (InP) colloidal quantum dots (CQDs) have generated great interest as next-generation light-emitting materials owing to their narrow emission spectra and environment-friendly components. The minimized surface defects is essential to achieve narrow full-width at half-maximum (FWHM) and high photoluminescence quantum yield (PLQY). However, InP CQDs are readily oxidized in ambient condition, which results in formation of oxidation defect states on the surface of InP CQDs. Herein, we introduce a strategy to successfully passivate the surface defects of InP core by zinc complexes. The zinc carboxylates passivation reduces FWHM of InP CQDs from 130 nm to 70 nm and increases PLQY from 1% to 14% without shelling. Furthermore, the photoluminescence (PL) peak has shifted from 670 nm to 510 nm with an increase of zinc carboxylates passivation, which suggests that excessive zinc carboxylates functions as a size-regulating reagent in the synthesis.

Evaluation of the effectiveness of the use of carbon fibres using salt of ethylenediaminetetraacetic acid for the purification of water bodies from heavy metals

As a result of various human activities, a large amount of heavy metals enters water bodies. Restoration of the environment with the help of plants is of great interest all over the world due to the possibilities offered by phytoremediation technology. This article is devoted to the development of an approach to wastewater treatment from heavy metals using Eichhornia using carbon fibre, which contributes to greater absorption capacity. It is proposed to use carbon fibre as “artificial roots” of plants. The article presents a scheme of an experimental setup with the use of carbon fibre in various combinations, including the use of a chelating agent - disodium salt of ethylenediaminetetraacetic acid (Trilon B) with various degrees of washing. It has been established that Eichhornia shows good results in the accumulation of heavy metals (Cu, Ni, Zn) in plant organs. The results indicate a positive effect from the use of carbon fibre as “artificial roots” in combination with Trilon B in relation to copper and zinc. The amount of remaining сopper and zinc in the water is the lowest at 4% and 8%. • Wastewater treatment from excess zinc, copper, and nickel. • Use of carbon fibres and chelating agent Trilon B for water treatment. • Sorption of copper, zinc, and nickel from wastewater using carbon fibres and Trilon B. • The efficiency of wastewater treatment from zinc and copper was more than 90%. • Carbon fibre and Trilon B can be used to improve wastewater treatment from heavy metals (Zn, Cu).

PO112 / #709 A MODEL OF SYNAPTIC CLEFT ZINC CHANGES IN HIPPOCAMPAL CA3 AREA ASSOCIATED WITH STRONG STIMULATION: E-POSTER VIEWING

The passage of information in neuronal chemical synapses is largely mediated by the excitatory neurotransmitter glutamate. Zinc, a transition metal highly abundant in hippocampal mossy fibers, is co-released with glutamate from their terminals. Following excessive vesicular zinc release to the synaptic cleft, zinc may enter the postsynaptic region. Temporal zinc concentration changes in the mossy fiber synaptic cleft were modelled for maximum free zinc concentrations of 10 μM to 500 μM. The model considers various zinc-dependent synaptic mechanisms, including glutamate receptors and voltage-dependent calcium channels (VDCCs), which contain specific zinc binding sites.

Excess dietary zinc drives a Cushing's-like syndrome in ovariectomized mice – Implications for postmenopausal obesity

Postmenopausal women have an increased risk of obesity, but the underlying cause is not clear. We unexpectedly found that excess dietary zinc induced severe obesity and a Cushing's-like syndrome without increased food intake in ovariectomized (Ovx) but not in sham-operated mice. Zinc accumulated in the adrenal glands and inhibited adrenal 17,20-lyase activity and steroid synthesis. As adrenal steroids are the only source of estrogen in Ovx mice, estrogen deficiency induced adrenal hyperplasia, glucocorticoid overproduction, and consequent development of a Cushing's-like syndrome. Adrenal steroid supplementation prevented the effects of zinc. Plasma zinc was positively correlated with cortisol level and negatively correlated with the levels of adrenal steroids and estrogen in obese postmenopausal women. The finding of a link between dietary zinc, estrogen deficiency, and postmenopausal obesity, implies that postmenopausal obesity might be prevented by supplementation with a adrenal steroid and avoiding excess dietary zinc.

Combined Impact of Excess Zinc and Cadmium on Elemental Uptake, Leaf Anatomy and Pigments, Antioxidant Capacity, and Function of Photosynthetic Apparatus in Clary Sage (Salvia sclarea L.).

Clary sage (Salvia sclarea L.) is a medicinal plant that has the potential to be used for phytoextraction of zinc (Zn) and cadmium (Cd) from contaminated soils by accumulating these metals in its tissues. Additionally, it has been found to be more tolerant to excess Zn than to Cd stress alone; however, the interactive effects of the combined treatment with Zn and Cd on this medicinal herb, and the protective strategies of Zn to alleviate Cd toxicity have not yet been established in detail. In this study, clary sage plants grown hydroponically were simultaneously exposed to Zn (900 µM) and Cd (100 μM) for 8 days to obtain more detailed information about the plant responses and the role of excess Zn in mitigating Cd toxicity symptoms. The leaf anatomy, photosynthetic pigments, total phenolic and anthocyanin contents, antioxidant capacity (by DPPH and FRAP analyses), and the uptake and distribution of essential elements were investigated. The results showed that co-exposure to Zn and Cd leads to an increased leaf content of Fe and Mg compared to the control, and to increased leaf Ca, Mn, and Cu contents compared to plants treated with Cd only. This is most likely involved in the defense mechanisms of excess Zn against Cd toxicity to protect the chlorophyll content and the functions of both photosystems and the oxygen-evolving complex. The data also revealed that the leaves of clary sage plants subjected to the combined treatment have an increased antioxidant capacity attributed to the higher content of polyphenolic compounds. Furthermore, light microscopy indicated more alterations in the leaf morphology after Cd-only treatment than after the combined treatment. The present study shows that excess Zn could mitigate Cd toxicity in clary sage plants.

Excessive Zinc Ion Caused PC12 Cell Death Correlating with Inhibition of NOS and Increase of RAGE in Cells.

Zinc ion (Zn2+) is an important functional factor; however, excessive Zn2+ can be toxic. To understand the neurotoxicity of excessive Zn2+ and the underlying mechanism, PC12 cells were treated with excessive Zn2+ and Zn2+ plus N, N, N', N'-Tetrakisethylenediamine (TPEN), a zinc ion chelator agent. Trypan blue and 3-(4,5-dimethyl-2- thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, thiazolyl blue tetrazolium bromide (MTT) assays were used to test cell viability; the relative kits were used to detect the activity of NOS synthase and the content of the receptor for advanced glycation end product (RAGE) in cells. We observed that excessive zinc caused PC12 cell damage and that TPEN partially reversed cell damage caused by excessive zinc. In addition, excessive zinc decreased total nitric oxide synthase (TNOS) activity in cells, in which constitutive nitric oxide synthase (cNOS) activity was significantly reduced; however, inducible nitric oxide synthase (iNOS) activity was extremely promoted. Moreover, excessive zinc upregulated the expression of RAGE, and TPEN effectively reversed the increase in RAGE induced by excessive zinc ions. Therefore, we concluded that excessive zinc caused PC12 cell damage, correlating with the inhibition of NOS and increase of RAGE induced in cells.

Adverse Effects of Excessive Zinc Intake in Infants and Children Aged 0-3 Years: A Systematic Review and Meta-Analysis.

Zinc supplementation reduces morbidity, but evidence suggests that excessive intakes can have negative health consequences. Current guidelines of upper limits (ULs) of zinc intake for young children are extrapolated from adult data. This systematic review (PROSPERO; registration no. CRD42020215187) aimed to determine the levels of zinc intake at which adverse effects are observed in young children. Studies reporting potential adverse effects of zinc intake in children aged 0-3 y were identified (from inception to August 2020) in MEDLINE, Embase, and the Cochrane Library, with no limits on study design. Adverse clinical and physical effects of zinc intake were synthesized narratively, and meta-analyses of biochemical outcomes were conducted. Random effects models were used to generate forest plots to examine the evidence by age category, dose, dose duration, chemical formula of zinc, and zinc compared with placebo. The Joanna Briggs Institute Critical Appraisal Checklist, Cochrane Risk of Bias 2, and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guideline were employed to assess risk of bias and to appraise the certainty of evidence. Fifty-eight studies assessed possible adverse effects of zinc doses ranging from 3 to 70mg/d. Data from 39 studies contributed to meta-analyses. Zinc supplementation had an adverse effect on serum ferritin, plasma/serum copper concentration, serum transferrin receptor, hemoglobin, hematocrit, and the odds of anemia in ≥1 of the subgroups investigated. Lactulose:mannitol ratio was improved with zinc supplementation, and no significant effect was observed on C-reactive protein, erythrocyte superoxide dismutase, zinc protoporphyrin, blood cholesterol, and iron deficiency anemia. The certainty of the evidence, as assessed using GRADE, was very low to moderate. Although possible adverse effects of zinc supplementation were observed in some subgroups, it is unclear whether these findings are clinically important. The synthesized data can be used to undertake a dose-response analysis to update current guidelines of ULs of zinc intake for young children.

Investigation of Biomarkers in Sub-Acute Hepatorenal Toxicity against Bulk and Zinc Oxide Nanoparticles Exposed Mice

Zinc oxide nanoparticles have been utilized and produced at a very large scale due to their wide range of applications. Nevertheless, its toxicity is one of the concerns addressed by various researchers. Widely used methods of measuring plasma zinc have poor sensitivity and impaired specificity. Currently, there is no specific biomarker for determination of excess zinc inside our body is explored well. Furthermore, it is vital to know the toxic effects of zinc oxide nanoparticles and their bulk counterparts at early exposure level on human health due to day to day increased use of zinc oxide nanoparticles in various applications. In current study we investigate the kidney and liver as the primary target organs for toxicity and their oxidative stress parameters. Twenty-four male mice were divided into three groups(n=8). Control (group I) served as vehicle control; group II:50mg/kg ZnO (bulk) and group III:ZnO NPs (50mg/kg nano). The mice were sacrificed after 14 days exposure, liver and kidney tissue toxicity biomarkers were performed. Our results demonstrate increased levels of GPx, metallothionein, GST, and decrease level of ceruloplasmin, GSH:GSSG ratio in bulk ZnO administered animals. The acute kidney toxicity was further confirmed by increased levels of their biomarkers i.e. Kim-1 and Clusterin. The levels of serum cytokines and caspase were also analyzed. Hence, this study investigated the comparative effect of early exposure of zinc oxide nanoparticles (nZnO) and its bulk form and we conclude that at 50mg/kg b.wt dose, ZnO NPs is comparatively safe to bulk ZnO.

Consumption of young child formulae in the Netherlands

PurposeAdequate micronutrient intakes are essential for young children. Special young child formulae (YCF) intended for children from 1 year old are available in the Dutch market. Since YCF are enriched with many micronutrients, it has the potential to have a beneficial effect on young children, or might pose a risk on excessive micronutrient intakes. The current study investigated the characteristics of YCF users, and the effect of YCF use on micronutrient intakes.MethodsData from the Dutch National Food Consumption Survey (2012–2016; n = 440 children aged 1–2 year old) and the Dutch Food Composition Database (NEVO version 2016) were used to assess micronutrient intakes. Habitual intakes of users and non-users of YCF were calculated using Statistical Program to Assess Dietary Exposure (SPADE) and compared.ResultsIn the Netherlands, YCF was consumed by 21% of the 1–2-year-olds. YCF contributed mostly to total vitamin D intake (76%) and between 0 and 50% for other micronutrients. Higher vitamin A, B1, C, D, E, total folate, iron and zinc intakes were observed among users, and higher potassium and phosphorus intakes were found among non-users. Risk of inadequate intake was low among both users and non-users for most nutrients, and the only elevated risk of excessive intake found was for zinc among YCF users.ConclusionYCF increased micronutrient intake, however, for most of the micronutrients there is already a low risk of inadequate intake. YCF increased the risk of excessive zinc intake. It is important that the addition of micronutrients to YCF is regulated, to prevent excessive intake.

Spastic Paraplegia and Ataxia in a Welder.

A 51-year-old welder (nonsmoker) developed subacute lower paresthesias and progressive spastic paraplegia and ataxia. Symptoms appeared 10 days after the first zinc exposure in the yacht construction site (8-hour day/40 days in a confined space with face shield only). Examination revealed loss of vibratory sensation, spasticity, hyperreflexia, and sensory ataxia. Serum heavy metals (Cu 1 mg/L and Pb 4,22 μg/L), B-complex vitamins, and paraneoplastics on serum and CSF were unremarkable. The elevated zinc level (137 μg/dL) was found. Spinal MRI showed combined degeneration (Figure). Myelopathy in zinc smelter workers was reported in the 19th century1 and recently rediscovered in excessive zinc ingestion. Copper secondary deficiency is hypothesized even if the normal copper serum level is reported.2 Two months later, copper became low (0.8 mg/L), a time-dependent process might explain late copper deficiency in our case. Symptoms ameliorated 4 months later with normalization of serum zinc/copper levels.

Nanomaterial-Based Zinc Ion Interference Therapy to Combat Bacterial Infections.

Pathogenic bacterial infections are the second highest cause of death worldwide and bring severe challenges to public healthcare. Antibiotic resistance makes it urgent to explore new antibacterial therapy. As an essential metal element in both humans and bacteria, zinc ions have various physiological and biochemical functions. They can stabilize the folded conformation of metalloproteins and participate in critical biochemical reactions, including DNA replication, transcription, translation, and signal transduction. Therefore, zinc deficiency would impair bacterial activity and inhibit the growth of bacteria. Interestingly, excess zinc ions also could cause oxidative stress to damage DNA, proteins, and lipids by inhibiting the function of respiratory enzymes to promote the formation of free radicals. Such dual characteristics endow zinc ions with unparalleled advantages in the direction of antibacterial therapy. Based on the fascinating features of zinc ions, nanomaterial-based zinc ion interference therapy emerges relying on the outstanding benefits of nanomaterials. Zinc ion interference therapy is divided into two classes: zinc overloading and zinc deprivation. In this review, we summarized the recent innovative zinc ion interference strategy for the treatment of bacterial infections and focused on analyzing the antibacterial mechanism of zinc overloading and zinc deprivation. Finally, we discuss the current limitations of zinc ion interference antibacterial therapy and put forward problems of clinical translation for zinc ion interference antibacterial therapy.

The Impact of Zinc and Zinc Homeostasis on the Intestinal Mucosal Barrier and Intestinal Diseases.

Zinc is an essential trace element for living organisms, and zinc homeostasis is essential for the maintenance of the normal physiological functions of cells and organisms. The intestine is the main location for zinc absorption and excretion, while zinc and zinc homeostasis is also of great significance to the structure and function of the intestinal mucosal barrier. Zinc excess or deficiency and zinc homeostatic imbalance are all associated with many intestinal diseases, such as IBD (inflammatory bowel disease), IBS (irritable bowel syndrome), and CRC (colorectal cancer). In this review, we describe the role of zinc and zinc homeostasis in the intestinal mucosal barrier and the relevance of zinc homeostasis to gastrointestinal diseases.

Zinc supplementation prevents arsenic-induced dysregulation of ZRANB2 splice function

Environmentally relevant (100 nM) inorganic arsenic (iAs) exposure displaces zinc from zinc fingers of upstream splice regulator ZRANB2 disrupting the splicing of its target TRA2B. Excess zinc displaced iAs from ZRANB2 zinc fingers in cell free system. Thus, the hypothesis that zinc supplementation could prevent iAs-mediated disruption of ZRANB2 splice function in human keratinocytes was tested. The data show that zinc supplementation prevented iAs-induced dysregulation of TRA2B splicing by ZRANB2 as well as the induction of ZRANB2 protein expression. These results provide additional support for the hypothesis that zinc supplementation could prevent iAs-mediated disease in iAs-exposed populations.

A single sensor controls large variations in zinc quotas in a marine cyanobacterium

Marine cyanobacteria are critical players in global nutrient cycles that crucially depend on trace metals in metalloenzymes, including zinc for CO2 fixation and phosphorus acquisition. How strains proliferating in the vast oligotrophic ocean gyres thrive at ultra-low zinc concentrations is currently unknown. Using Synechococcus sp. WH8102 as a model we show that its zinc-sensor protein Zur differs from all other known bacterial Zur proteins in overall structure and the location of its sensory zinc site. Uniquely, Synechococcus Zur activates metallothionein gene expression, which supports cellular zinc quotas spanning two orders of magnitude. Thus, a single zinc sensor facilitates growth across pico- to micromolar zinc concentrations with the bonus of banking this precious resource. The resultant ability to grow well at both ultra-low and excess zinc, together with overall lower zinc requirements, likely contribute to the broad ecological distribution of Synechococcus across the global oceans.

127 Hypocupraemia-induced anaemia, sensory ataxia and cognitive impairment secondary to zinc-containing dental adhesive

A previously fit and well 67 year old male presented with a 5-month history of gradually worsening memory impairment and sensory gait ataxia on the background of recent symptomatic anaemia. He experienced multiple falls and became agitated and socially withdrawn over a 3-week period, resulting in hospital admission. On examination, he had sensory gait ataxia consistent with a dorsal column syndrome. He had a Montreal Cognitive Assessment score of 13. Serum analysis showed normocytic anaemia and leukopenia, severe hypocupraemia, reduced caeruloplasmin and normal zinc levels. Overuse of zinc- containing denture cream was identified as being a cause of excess zinc ingestion and resultant copper deficiency, leading to blood dyscrasia and myelopathy. The cream was withdrawn and IV copper followed by oral supplementation was implemented. Direct questions with regards to excess zinc in the diet and serological testing of copper and zinc should be considered in any patient with a dorsal column syndrome, particularly with concurrent anaemia. Copper deficiency may also have a role in exacerbat- ing pre-existing cognitive impairment.rnj1e16@soton.ac.uk