Total Zinc Content Research Articles

Modelling zinc changes at the hippocampal mossy fiber synaptic cleft.

Zinc, a transition metal existing in very high concentrations in the hippocampal mossy fibers from CA3 area, is assumed to be co-released with glutamate and to have a neuromodulatory role at the corresponding synapses. The synaptic action of zinc is determined both by the spatiotemporal characteristics of the zinc release process and by the kinetics of zinc binding to sites located in the cleft area, as well as by their concentrations. This work addresses total, free and complexed zinc concentration changes, in an individual synaptic cleft, following single, short and long periods of evoked zinc release. The results estimate the magnitude and time course of the concentrations of zinc complexes, assuming that the dynamics of the release processes are similar to those of glutamate. It is also considered that, for the cleft zinc concentrations used in the model (≤ 1μM), there is no postsynaptic zinc entry. For this reason, all released zinc ends up being reuptaken in a process that is several orders of magnitude slower than that of release and has thus a much smaller amplitude. The time derivative of the total zinc concentration in the cleft is represented by the difference between two alpha functions, corresponding to the released and uptaken components. These include specific parameters that were chosen assuming zinc and glutamate co-release, with similar time courses. The peak amplitudes of free zinc in the cleft were selected based on previously reported experimental cleft zinc concentration changes evoked by single and multiple stimulation protocols. The results suggest that following a low amount of zinc release, similar to that associated with one or a few stimuli, zinc clearance is mainly mediated by zinc binding to the high-affinity sites on the NMDA receptors and to the low-affinity sites on the highly abundant GLAST glutamate transporters. In the case of higher zinc release brought about by a larger group of stimuli, most zinc binding occurs essentially to the GLAST transporters, having the corresponding zinc complex a maximum concentration that is more than one order of magnitude larger than that for the high and low affinity NMDA sites. The other zinc complexes considered in the model, namely those formed with sites on the AMPA receptors, calcium and KATP channels and with ATP molecules, have much smaller contributions to the synaptic zinc clearance.

In Vitro Zinc Protoporphyrin IX Formation in Different Meat Sources Related to Potentially Important Intrinsic Parameters

For several years, researchers have studied the formation of zinc protoporphyrin IX in meat, as it is considered to be an important natural colouring agent in dry cured or fermented meat products in the absence of nitrite and/ or nitrate. Until now, however, mainly pork meat is used for these investigations. The goal of this research was to relate in vitro zinc protoporphyrin IX and protoporphyrin IX formation in eight meat sources (chicken, turkey, pork, lamb, beef, veal, horse and porcine liver) to eight intrinsic parameters using partial least squares regression (PLS) analysis. Significant differences in pH, initial metmyoglobin formation, metmyoglobin reduction ability, total heme, zinc chelatase activity, and total iron and zinc concentration between meat sources were found. Water activity, however, was not significantly different between meat sources. Liver tissue and horse meat showed the best ability to form zinc protoporphyrin IX. Formation of protoporphyrin IX was limited in all meat sources. PLS analysis revealed that mainly zinc chelatase activity, followed by total heme, total iron and zinc content, were predominant intrinsic parameters to explain variations in zinc protoporphyrin IX formation. These findings could be important for meat industry in order to establish the production of red coloured nitrite-free meat products.

Organic Wheat Farming Improves Grain Zinc Concentration.

Zinc (Zn) nutrition is of key relevance in India, as a large fraction of the population suffers from Zn malnutrition and many soils contain little plant available Zn. In this study we compared organic and conventional wheat cropping systems with respect to DTPA (diethylene triamine pentaacetic acid)-extractable Zn as a proxy for plant available Zn, yield, and grain Zn concentration. We analyzed soil and wheat grain samples from 30 organic and 30 conventional farms in Madhya Pradesh (central India), and conducted farmer interviews to elucidate sociological and management variables. Total and DTPA-extractable soil Zn concentrations and grain yield (3400 kg ha-1) did not differ between the two farming systems, but with 32 and 28 mg kg-1 respectively, grain Zn concentrations were higher on organic than conventional farms (t = -2.2, p = 0.03). Furthermore, multiple linear regression analyses revealed that (a) total soil zinc and sulfur concentrations were the best predictors of DTPA-extractable soil Zn, (b) Olsen phosphate taken as a proxy for available soil phosphorus, exchangeable soil potassium, harvest date, training of farmers in nutrient management, and soil silt content were the best predictors of yield, and (c) yield, Olsen phosphate, grain nitrogen, farmyard manure availability, and the type of cropping system were the best predictors of grain Zn concentration. Results suggested that organic wheat contained more Zn despite same yield level due to higher nutrient efficiency. Higher nutrient efficiency was also seen in organic wheat for P, N and S. The study thus suggests that appropriate farm management can lead to competitive yield and improved Zn concentration in wheat grains on organic farms.

Differences in Breast Milk Composition of HIV-Infected and HIV-Uninfected Mothers of Premature Infants: Effects of Antiretroviral Therapy.

A key strategy to prevent mother-to-child transmission of the human immunodeficiency virus (HIV) and to reduce infant morbidity and mortality includes providing the HIV-exposed premature infant with breast milk accompanied by dual anti-retroviral therapy (ART). The effects of HIV and ART on premature breast milk composition are largely unknown. The aim of the study was to assess and compare the breast milk composition of HIV-infected mothers receiving ART and HIV-uninfected mothers who gave birth to premature infants. Lactating HIV-infected women receiving ART (n = 38) and HIV-uninfected women (n = 36) with premature infants provided two breast milk samples on days 7 and 9, respectively, of lactation. Breast milk samples were analyzed for total energy, protein, carbohydrates, fat, phosphate, iron, zinc, and copper content. Breast milk of HIV-infected women contained higher protein (1.95 versus 1.78 g/100 g; p = 0.04), fat (4.42 versus 3.49 g/100 g; p = 0.01), and copper (0.64 versus 0.56 mg/L; p = 0.02) levels; whereas carbohydrate (5.37 versus 6.67 g/100 g; p = 0.002) and zinc (5.26 versus 5.78 mg/L; p = 0.04) levels were lower compared with those of HIV-uninfected women. Zinc levels were significantly lower in HIV-infected women with early gestation periods, and the lowest levels were observed in women who received ART for ≤4 weeks (0.58 mg/L; p = 0.03). Total energy (78.22 versus 61.48 kCal/100 mL) and fat levels (5.39 versus 3.00 g/100 mL) were significantly higher in the late gestation period HIV-infected women. Copper levels (0.61 mg/L) were higher in the late gestation period women who received >4 weeks of ART exposure (p = 0.05). Differences existed in the breast milk composition of HIV-infected women on ART compared with HIV-uninfected women. ART exposure period may influence breast milk composition.

Zinc status, dietary zinc intake and metabolic risk in Australian children and adolescents; Nepean Longitudinal Study.

Zinc is essential for normal growth and metabolism. We aimed to characterise the total and bioavailable dietary zinc intake and plasma zinc concentrations in healthy children, longitudinally, and to examine the association between plasma zinc concentrations, dietary zinc intake and cardiometabolic markers in the same cohort. A secondary data analysis of a prospective cohort study, the Nepean Longitudinal Study, which followed an Australian birth cohort at ages 8 (n=436) and 15years (n=290) collecting dietary, anthropometry and biochemistry data (plasma zinc, fasting glucose, insulin and lipid profile). Diet was assessed by a 3-day food record and a food frequency questionnaire at 8 and 15years, respectively. Zinc bioavailability was determined by the phytate/zinc molar ratio. At 8years, the median zinc intake was 7.84mg (interquartile range 6.57-9.35) for boys and 7.06mg (5.98-8.30) for girls. Three of 345 children reported inadequate absorbable zinc intake, and none reported inadequate total zinc intake. At 15years, median zinc intake was 11.8mg (9.41-14.8) for boys and 8.54mg (6.76-10.7) for girls. The prevalence of inadequate intakes of absorbable zinc and total zinc was 19 and 29%, respectively. Plasma zinc concentration was not correlated with dietary zinc intake, adiposity nor lipids at either time point, but it was inversely correlated with fasting glucose at 8year and with insulin at 15years. Australian children had an overall adequate zinc status. However, adolescents who reported suboptimal dietary zinc intakes were more likely to have raised insulin concentrations.

Metallothioneins 1 and 2, but not 3, are regulated by nutritional status in rat white adipose tissue.

BackgroundCumulating evidence underlines the role of adipose tissue metallothionein (MT) in the development of obesity and type 2 diabetes. Fasting/refeeding was shown to affect MT gene expression in the rodent liver. The influence of nutritional status on MT gene expression in white adipose tissue (WAT) is inconclusive. The aim of this study was to verify if fasting and fasting/refeeding may influence expression of MT genes in WAT of rats.ResultsFasting resulted in a significant increase in MT1 and MT2 gene expressions in retroperitoneal, epididymal, and inguinal WAT of rats, and this effect was reversed by refeeding. Altered expressions of MT1 and MT2 genes in all main fat depots were reflected by changes in serum MT1 and MT2 levels. MT1 and MT2 messenger RNA (mRNA) levels in WAT correlated inversely with serum insulin concentration. Changes in MT1 and MT2 mRNA levels were apparently not related to total zinc concentrations and MTF1 and Zn transporter mRNA levels in WAT. Fasting or fasting/refeeding exerted no effect on the expression of MT3 gene in WAT. Addition of insulin to isolated adipocytes resulted in a significant decrease in MT1 and MT2 gene expressions. In contrast, forskolin or dibutyryl-cAMP (dB-cAMP) enhanced the expressions of MT1 and MT2 genes in isolated adipocytes. Insulin partially reversed the effect of dB-cAMP on MT1 and MT2 gene expressions.ConclusionsThis study showed that the expressions of MT1 and MT2 genes in WAT are regulated by nutritional status, and the regulation may be independent of total zinc concentration.Electronic supplementary materialThe online version of this article (doi:10.1186/s12263-016-0533-3) contains supplementary material, which is available to authorized users.

Acceptability and solubility of iron and zinc contents of modified Moringa oleifera sauces consumed in the Far-north region of Cameroon.

Consumption of Moringa oleifera leaves is a local and inexpensive solution to iron and zinc deficiencies in the Far‐north region of Cameroon. However, traditional household's cooking techniques result in sauces with high pH levels and low leaves incorporation rates that compromise the bioavailability of iron and zinc. The aim of our study was to investigate the effect of modifying a standard Moringa sauce on consumer acceptability and the solubility of iron and zinc, which is an indicator of their bioavailability. Lime juice or tamarind pulp was added to a standard recipe in order to reduce the pH by about one unit, and Moringa leaf powder was incorporated in each acidulated sauce at three levels (1, 2, and 4 g/100 g of sauce). All the formulations were evaluated for their acceptability by 30 housewives using a five‐point hedonic scale. The pH was measured by a digital electronic pH‐meter. Moisture and ash were determined by AOAC methods. Total iron and zinc contents were determined by atomic absorption spectrophotometry, and soluble iron and zinc by HCl‐extractability. The lime juice‐acidulated sauce and the tamarind pulp‐acidulated sauce enriched with 1 g of Moringa leaf powder were the most acceptable formulations with scores of 3.4 and 3.6, respectively. Their chemical analysis showed a reduced pH (6.4 and 6.1, respectively), compared to the Control (7.2). Lime juice‐acidulated sauce improved iron and zinc solubility from 42.19 to 66.38% and 54.03 to 82.03%, respectively. Tamarind pulp‐acidulated sauce enriched with 1 g of Moringa leaf powder showed a decrease in iron solubility from 42.19 to 38.26% and an increase in zinc solubility from 54.03 to 72.86%. These results confirm the beneficial effect of lime juice in improving iron and zinc bioavailability.

Validation of artificial neural network models for predicting biochemical markers associated with male infertility

ABSTRACTSeminal fluid is the secretion from many glands comprised of several organic and inorganic compounds including free amino acids, proteins, fructose, glucosidase, zinc, and other scavenging elements like Mg2+, Ca2+, K+, and Na+. Therefore, in the view of development of novel approaches and proper diagnosis to male infertility, overall understanding of the biochemical and molecular composition and its role in regulation of sperm quality is highly desirable. Perhaps this can be achieved through artificial intelligence. This study was aimed to elucidate and predict various biochemical markers present in human seminal plasma with three different neural network models. A total of 177 semen samples were collected for this research (both fertile and infertile samples) and immediately processed to prepare a semen analysis report, based on the protocol of the World Health Organization (WHO [2010]). The semen samples were then categorized into oligoasthenospermia (n=35), asthenospermia (n=35), azoospermia (n=22), normospermia (n=34), oligospermia (n=34), and control (n=17). The major biochemical parameters like total protein content, fructose, glucosidase, and zinc content were elucidated by standard protocols. All the biochemical markers were predicted by using three different artificial neural network (ANN) models with semen parameters as inputs. Of the three models, the back propagation neural network model (BPNN) yielded the best results with mean absolute error 0.025, -0.080, 0.166, and -0.057 for protein, fructose, glucosidase, and zinc, respectively. This suggests that BPNN can be used to predict biochemical parameters for the proper diagnosis of male infertility in assisted reproductive technology (ART) centres.Abbreviations: AAS: absorption spectroscopy; AI: artificial intelligence; ANN: artificial neural networks; ART: assisted reproductive technology; BPNN: back propagation neural network model; DT: decision tress; MLP: multilayer perceptron; PESA: percutaneous epididymal sperm spiration; RBFN: radical basis function network; SRNN: simple recurrent neural network; SVM: support vector machines; TSE: testicular sperm extraction; WHO: World Health Organization

Temporal variation of total and DTPA-extractable heavy metal contents as influenced by sewage sludge and perlite in a calcareous soil

ABSTRACTContinuous application of sewage sludge (SS) as a source of organic matter, may increase available heavy metals (HMs) up to their critical levels. As a consequence their uptake by plants, risks of accumulation in food chain and groundwater pollution increases. To evaluate the effects of perlite and SS on total content and available fraction of iron (Fe), manganese (Mn), lead (Pb), copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) over 45 and 90 days a completely randomized pot experiment was conducted. Treatments consisted of SS (0, 2 and 4%) and combined SS and perlite levels (1:1, 1.5:0.5 and 0.5:1.5% SS:perlite). Mean available Fe, Ni, Cd, Mn and Zn fractions decreased over time by 7–27%, whereas, total contents did not change. Available HMs in SS-treated soils increased by 0.5–25%; whereas, only total Zn, Cu and Pb concentrations increased with SS application (although concentrations fall in the range of critical levels). The lowest (1.6 fold) and highest (22.1 fold) increases obtained for available Cu and Zn, respectively. Perlite could mitigate the adverse effect of high rate application of SS on amplification of HMs extractability. Therefore, their concomitant applications can be suggested considering the perlite durability and its positive effects on soil physical properties.

Level of zinc in maize seeds and maize growing soils of central Mecha, Amhara National Regional State of Ethiopia

Ethiopia is one of the world countries with reported zinc deficiency or high probability of zinc deficiency. Zinc deficiency is an important soil constraint to crop production, food quality and human health. The aim of this study was to evaluate the zinc concentration of different cultivars of maize seeds and soil samples in central Mecha area using a laboratory analysis to establish whether the roles and effects of zinc in crop productivity and quality in the area could be significant due to plant factors (e.g. cultivar) or changes in soil nutrient zinc concentration or both. Thirty representative soil samples from seven kebeles of the central Mecha and six genotypes of maize grains (Bako Hybrid-540, Bako Hybrid-543, Bako Hybrid-660, Pioneer Hybrid-3253, Melkassa Hybrid-2, and Melkassa Hybrid-4) available in the region for farmers archived by Ethiopian Seed Enterprise (ESE) were collected and analyzed in the laboratory. Zinc levels were determined by FAAS using wet digestion and dilute acid extraction methods. The mean pH (KCl) value of the soils indicated the samples studied are acidic (pH = 4.60). The means and ranges of concentrations of total zinc using strong acids wet digestion and available HCl-extractable zinc in soils (mg Kg -1 DW) were 50.49 mg Kg -1 (44.80 to 65.22 mg Kg -1 ) and 2.95 mg Kg -1 (1.76 to 4.94 mg Kg -1 ), respectively. ANOVA analysis revealed significant differences (P < 0.05) between maize varieties in zinc levels. There was significant genetic variability in the level of zinc between the maize cultivars from 16.18 mg Kg -1 for Bako Hybrid-540; 20.08 mg Kg -1 for Bako Hybride-660; 21.08 mg Kg -1 for Pioneer Hybrid-3253; 23.26 mg Kg -1 for Bako Hybrid-543; 29.38 mg Kg-1 for Melkassa-2 to 32.52 mg kg -1 for Melkassa-4. Chemical analysis of composite soil samples indicated that inherent zinc level was on the borderline sufficiency to support good crop growth for now, however; the variations in the level of zinc among the different maize cultivars should be significant in limiting high and quality yield for consumption. Adequate zinc in soils and high zinc concentrations in seeds ensure agronomic and nutritional benefits resulting in high yield and nutritional quality crops. Keywords : Crops, Micronutrients, Zinc deficiency, Soil acidity, Ethiopia

Comparison of serum trace elements and antioxidant levels in terrier dogs with or without behavior problems

The aim of the present study was to investigate the amounts of serum trace elements (copper, iron and zinc) and antioxidants (malondialdehyde, total antioxidant capacity and thiol group) in terrier dogs with six common behavior problems, namely, excessive activity, inappropriate elimination, fearfulness, destructiveness, aggression towards people, and aggression towards dogs. Information was collected from successfully completed questionnaires and two groups of dogs were selected: control group (dogs without any behavior problem, n=14) and test group (dogs with at least one common behavior problem, n=16). Serum total antioxidant capacity and zinc concentration in terrier dogs with behavior problem was significantly lesser than those in the control dogs (p<0.05). No significant differences were observed for malondialdehyde, thiol group, copper and iron concentration between the two groups. The present study showed different amounts of serum antioxidants and zinc in terrier dogs with behavior problems compared to the healthy dogs. This finding support the hypothesis that improved zinc and antioxidant status with food supplements may favor the prevention and resolution of behavioral problems in dogs.

Assessment of Selected Heavy metals and Enzymes in Soil within the Range of Impact of Illegal Dumping Sites

The paper demonstrates the result of changes in the physicochemical and biological properties in soil as a result of the operation of illegal dumping sites. Soil was sampled from the research points located on the outskirts of the city of Bydgoszcz (Poland) from the site not affected by illegal dumping sites (control C), within the dumping sites, having removed the waste layer (W), and 10 m away from the dumping sites (W 10). In the soil the content of phosphorus, potassium, magnesium and sulphur, total content of copper, zinc, lead and nickel as well as the activity of enzymes were assayed. The content of Pb, Zn, Cu and Ni in the soil samples qualifies the soils as representing the soil category with natural content. The greatest activity of all the enzymes analysed was identified in the soil sampled from the control point affected by waste, whereas the highest content of macroelements was reported in the soil from the dumping sites (W 10). A high variation in the enzymes under study in soils confirms a high value of the coefficient of variation (CV >36%). The analysis of correlation confirmed the relationship between the content of organic carbon compounds and the content of zinc, lead, nickel. The soils show a slight value of the coefficient of contamination for heavy metals (CF<1). The contamination degree (Cdeg) ranged from 1.993 to 5.116, which points to a low level of soil contamination with Zn, Cu, Pb and Ni.

A Comparative Study of Total and Bioavailable Cadmium and Zinc Concentrations and Distributions among Different Land Use Types within Baghdad City

Total and bioavailable levels of Cd and Zn in topsoil (0–20) cm taken from four different land use types (residential, commercial, industrial and mixed) of the urban area of Bagdad, Iraq, were analyzed by the flame atomic absorption spectrophotometer. This was with a view to appraising the influence of a variety of anthropogenic activities on heavy metal contamination of the urban soil. Results showed that the range of Cd and Zn were (0.00-6.35) mg/kg and (5.20-219.95) mg/kg respectively. As compared with the calculated world average of unpolluted soils, cadmium displays higher concentrations while the zinc concentration was within this common world range. The level of pollution was assessed using geoaccumulation index (Igeo), for all land use types Igeo decreasing order, followed the order of (Cd> Zn). The relative bioavailability for Cd, and Zn has been observed as 2.46-5 % and 2.80-9.78 % respectively. It can be concluded that, although total concentrations of the examined heavy metals were generally high, but at the same time the bioavailable ones were relatively low. This can be an indicator that with the recent environmental factors (alkaline to sub-alkaline soil pH), the toxicity of heavy metals to humans was in its minimum level.

Multibiomarker toxicity characterization of uranium mine drainages to the fish Carassius auratus.

The release of acidic effluents, naturally enriched in metals and radionuclides, is the main legacy of uranium mines. Generally, metals dissolved by these acidic effluents can cause significant alterations in exposed organisms, with distinct toxicological outcomes. In this study, 72 individuals of the freshwater fish species Carassius auratus were exposed in situ for different periods (8, 16, 24, and 48h) to water from a pond (treatment pond (TP)) with a chemically treated effluent and a reference pond (PRP), in the vicinity of the Cunha Baixa uranium mine (Portugal). Comparing the water of the two ponds, the PRP pond was characterized by higher pH and oxygen values and lower conductivity and hardness values. Regarding total metal concentrations, among others, magnesium (56,000μg/L), sodium (17,400μg/L), zinc (86μg/L), manganese (6340μg/L), and uranium (1380μg/L) concentrations in the TP pond were above the values obtained for the PRP pond. The values of manganese and uranium exceeded the values of quality criteria established for surface waters for cyprinids and for irrigation purposes. After exposure to pond water, significant differences were recorded for several biomarkers: (i) between ponds for acetylcholinesterase (AChE) with higher activities for animals from the PRP and glutathione-S-transferase (GST) activities that were particularly enhanced in animals from the TP pond; (ii) between ponds and exposure periods for lactate dehydrogenase (LDH) activity, since organisms from PRP pond presented always higher values than those from the TP pond, and among these, organisms exposed for the longer period presented a further depression in LDH activity; and (iii) between exposure periods for erythrocyte micronucleus. GSTs and LDH were the most sensitive biomarkers within the timeframe of the in situ assay performed. Despite the alleged efficacy of the chemical treatment (evidenced by a significantly lower pH), some metals persisted in the treated effluent (TP pond), potentially contributing to the induction of oxidative stress or increased conjugation metabolic activity in fish.

Untreated runoff quality from roof and road surfaces in a low intensity rainfall climate

Sediment and heavy metals in stormwater runoff are key pollutants of urban waterways, and their presence in stormwater is driven by climatic factors such as rainfall intensity. This study describes the total suspended solids (TSS) and heavy metal concentrations found in runoff from four different urban surfaces within a residential/institutional catchment, in a climate where rainfall is typically of low intensity (<5.1mm·h−1). The results were compared to untreated runoff quality from a compilation of international studies. The road runoff had the highest TSS concentrations, while copper and galvanized roof runoff had the highest copper and zinc concentrations, respectively. Pollutant concentrations were found to be significantly different between surfaces; quantification and prediction of pollutant contributions from urban surfaces should thus take account of the different surface materials, instead of being aggregated into more generalized categories such as land use. The TSS and heavy metal concentrations were found to be at the low to medium end of ranges observed internationally, except for total copper and zinc concentrations generated by dissolution of copper and galvanized roofing material respectively; these concentrations were at least as high as those reported internationally. TSS wash-off from the roofs was seen to be a source-limited process, where all available TSS is washed off during the rain event despite the low intensity rainfall, whereas both road TSS and heavy metals wash-off from roof and road surfaces appeared to all be transport-limited and therefore some carryover of pollutants occurs between rain events. A first flush effect was seen from most surfaces for TSS, but not for heavy metals. This study demonstrates that in low intensity rainfall climates, quantification of untreated runoff quality from key individual surface types in a catchment are needed to enable development of targeted and appropriately sized stormwater treatment systems.

Zinc sensing by metal-responsive transcription factor 1 (MTF1) controls metallothionein and ZnT1 expression to buffer the sensitivity of the transcriptome response to zinc.

Only a small number of genes are known direct targets of the zinc-responsive transcription factor MTF1; therefore, the aim of this study was to gain a more complete understanding of the MTF-1 regulated zinc-responsive component of the transcriptome. A targeted siRNA was used to deplete MTF1 expression in the human intestinal cell line Caco-2. We predicted that the response to zinc of direct MTF1 target genes would be abrogated by MTF1 knockdown. Surprisingly, a greater number of genes were regulated by zinc following MFT1 knockdown, and most genes that responded to zinc under both control and MTF1-depleted conditions had an augmented response in the latter condition. Exceptions were the zinc effluxer ZnT1 and a suite of metallothionein genes, suggesting that responses of other genes to zinc are usually buffered by increases in these proteins. We propose that MTF1 heads a hierarchy of zinc sensors, and through controlling the expression of a raft of metallothioneins and other key proteins involved in controlling intracellular zinc levels (e.g. ZnT1) alters zinc buffering capacity and total cellular zinc content. We tested and validated this model by overexpressing metallothionein and observing the predicted curtailment in response of the zinc-repressed SLC30A5 (ZnT5) promoter. The model provides the framework for an integrated understanding of cellular zinc homeostasis. Because MTs can bind metals other than zinc, this framework links with overall cellular metal homeostasis.

Sugar and Mineral Content Analysis in Mungbean (Vigna radiata L.) Cultivars

The experimental trial on 12 mungbean cultivars were conducted and the findings of the pooled data of two years revealed that total soluble sugar, reducing sugar, non-reducing sugar, iron, copper and zinc content varied highly significantly across the tested cultivars and ranged from 3.64–5.22%, 0.65–0.85%, 2.85–4.57%, 10.95–15.27 mg/100g, 1.59–3.26 mg/100g and 2.59–3.55 mg/100g, respectively. The cultivar MUM-2 was found to contain maximum amount of total soluble sugar as well as non-reducing sugar and the minimum amount of reducing sugar. The minimum amount of total soluble sugar and non-reducing sugar were found in Pant M-4 and Pairy Mung, respectively. The reducing sugar was recorded highest in BPMR145 and lowest in MUM-2 along with Pant M-4. Iron as well as zinc were recorded highest in Samrat, while copper was recorded highest in Pusa-0672. The minimum amounts of these three minerals were present in PKV AKM-4.

Zinc Absorption by Adults Is Similar from Intrinsically Labeled Zinc-Biofortified Rice and from Rice Fortified with Labeled Zinc Sulfate

Biofortification of staple food crops is a promising strategy to combat zinc deficiency, and it is of particular interest for rice and crops that are not consumed as flours and therefore not suitable for postharvest fortification. Because zinc absorption is decreased by phytic acid (PA) and perhaps other dietary components, it is important to measure the absorption of zinc from a biofortified crop before determining its efficacy. In this study, we compared the zinc absorption from zinc-biofortified rice (hydroponically enriched with (70)Zn) with that from a control rice of the same variety fortified with (70)ZnSO4 at point of use to reach the same total zinc content of 1.1 mg/meal. Both rice meals had a PA:Zn molar ratio of 12. Fractional absorption of zinc (FAZ) was measured with the use of the double-isotope tracer ratio method in 16 apparently healthy adults [18-45 y old; BMI (in kg/m(2)) 19-25] who consumed 2 single meals at 4-wk intervals in random order in a crossover design. The FAZ from the biofortified rice (mean ± SD: 25.1 ± 8.7%) did not differ significantly from that of the point-of-use fortified rice (mean ± SD: 20.8 ± 7.1%) (P = 0.08). These results suggest that the native zinc accumulated in the biofortified rice was readily released from the rice matrix and that its absorption by adults was influenced by PA and other food components in a similar way to the inorganic zinc compound added to the rice at point of use. Moreover, rice biofortification is likely to be as good as postharvest zinc fortification as an intervention strategy to combat zinc deficiency. This trial was registered at clinicaltrials.gov as NCT01633450.

Zinc flexes its muscle: Correcting a novel analysis of calcium for zinc interference uncovers a method to measure zinc.

The divalent cation chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), often used to buffer physiological changes in cytosolic Ca(2+), also binds Zn(2+) with high affinity. In a recently published method (Lamboley et al. 2015. J. Gen. Physiol. http://dx.doi.org/10.1085/jgp.201411250), the absorbance shift of BAPTA at 292 nm was successfully used to determine the total calcium concentrations of various skeletal muscle tissues. In the present study, we show that endogenous Zn(2+) in rat skeletal muscle tissue can be unknowingly measured as "Ca(2+)," unless appropriate measures are taken to eliminate Zn(2+) interference. We analyzed two rat skeletal muscle tissues, soleus and plantaris, for total calcium and zinc using either inductively coupled plasma mass spectrometry (ICP-MS) or the BAPTA method described above. ICP-MS analysis showed that total zinc contents in soleus and plantaris were large enough to affect the determination of total calcium by the BAPTA method (calcium = 1.72 ± 0.31 and 1.96 ± 0.14, and zinc = 0.528 ± 0.04 and 0.192 ± 0.01; mean ± standard error of the mean [SEM]; n = 5; mmole/kg, respectively). We next analyzed total calcium using BAPTA but included the Zn(2+)-specific chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) that buffers Zn(2+) without affecting Ca(2+)/BAPTA binding. We found that estimated concentrations of total calcium ([CaT]WM) in soleus and plantaris were reduced after TPEN addition ([CaT]WM = 3.71 ± 0.62 and 3.57 ± 0.64 without TPEN and 3.39 ± 0.64 and 3.42 ± 0.62 with TPEN; mean ± SEM; n = 3; mmole/kg, respectively). Thus, we show that a straightforward correction can be applied to the BAPTA method to improve the accuracy of the determination of total calcium that should be applicable to most any tissue studied. In addition, we show that using TPEN in combination with the BAPTA method allows one to make reasonable estimates of total zinc concentration that are in agreement with the direct determination of zinc concentration by ICP-MS.

Potential of Tamarix africana and other halophyte species for phytostabilisation of contaminated salt marsh soils

Salt marsh plants are colonising wastes from a steel plant deposited on the Coina River Banks posing a potential contamination risk to the Tagus estuary ecosystem. The objectives of this study were to assess the uptake, accumulation and translocation of hazardous elements/nutrients in three spontaneous halophytic species, to evaluate the capacity of Tamarix africana to stabilise a contaminated salt marsh soil, and to evaluate the ecotoxicity of the pore water and elutriates from phytostabilised soils. The work comprises the following: fieldwork collection of soil samples from Coina River (an affluent of Tagus River) bank landfill, estuarine water and spontaneous plants (Aster tripolium, Halimione portulacoides and Sarcocornia sp.), and greenhouse studies (microcosm assay) with T. africana growing in one landfill salt marsh soil, for 97 days, and watered with estuarine water. Soils were analysed for pH, EC, Corganic, NPK, iron and manganese oxides. Soils total (acid digestion) elemental concentrations were determined by ICP/INAA. Estuarine waters, plants roots and shoots (acid digestion), soils available fraction (diluted organic acids extraction-RHIZO or pore water), and salts collected from the T. africana leaves surface were analysed for metals/metalloids (ICP-MS). Ecotoxicity assays were performed in T. africana soil elutriates and pore waters using Artemia franciscana and Brachionus plicatillis. Soils were contaminated, containing high total concentrations of arsenic, cadmium, chromium, copper, lead and zinc. However, their concentrations in the available fraction were <4 % of the total. The estuarine waters were contaminated with cadmium, but negligible ecotoxicological effect was observed. The spontaneous plants had significant uptake of the above elements, being mostly stored in the roots. Elemental concentrations in the shoots were within the normal range for plants. These species are not hazardous elements accumulators. Tamarix africana was well adapted to the contaminated saline soils, stored the contaminants in the roots, and had small concentrations of hazardous elements in the shoots. Excretion of hazardous elements by the salt glands was also observed. Elutriates from soils with and without plant did not show ecotoxicity. The salt marsh species play an important role in the stabilisation of the soils in natural conditions. Tamarix africana showed potential for phytostabilisation of saline-contaminated soils. The low translocation of the elements from roots to shoots and/or active excretion of the elements by the salt glands was a tolerance mechanism in T. africana.