Tissue Mn Research Articles

Elemental Composition and Health Risk Assessment of Giant Mudskipper (Periophthalmodon schlosseri) From the Intertidal Zone of the West Coast of Peninsular Malaysia

The elemental pollution in the intertidal zone of the West Coast of Peninsular Malaysia is of concern because this place is an ultimate sink of anthropogenic contaminants. In this study, the elemental concentrations (Al, Fe, Ba, Co, Cu, Cr, Mn, Ni, Pb, Zn, As, and Cd) in various tissues (muscle, gill, liver, gastrointestinal tract, and scale) of the giant mudskippers (Periophthalmodon schlosseri) from the West Coast of Peninsular Malaysia were determined by the inductively coupled plasma-mass spectrometry. The potential health risks associated with fish muscle consumption were assessed using estimated weekly intake (EWI), target hazard quotient (THQ), and target cancer risk (TR). The results showed that relatively high concentrations of Fe (1,641.91 ± 96.77 mg/kg), Ba (7.07 ± 0.05 mg/kg), Co (0.32 ± 0.00 mg/kg), Mn (36.08 ± 0.04 mg/kg), and Ni (4.43 ± 0.06 mg/kg) were found in the fish scales, suggesting the uptake waterborne elements via dermal exposure. However, all studied elements in the fish muscle were below the national and international food permissible limits. Health risk assessment through the estimation of THQ suggested that long-term exposure of As through fish consumption would cause possible non-carcinogenic risk. Also, the estimation of TR indicated that consumers are susceptible to cancer risks because of Cr and As exposure via fish consumption. Thus, for a developing country like Malaysia, it is recommended to include continuous monitoring of intertidal zones, using potential bioindicators, to assess ecosystem health status and safeguard human health. Additionally, mitigation strategies to address estuaries contamination and efforts to conserve and sustain natural resources should be established.

Experimental Investigation of Some Heavy Metals in the Muscle Tissue of Cultured African Catfish (Clarias gariepinus)

Often times, environmental scientist believes that heavy metal contamination of aquatic ecosystem is related only to fishes in aquatic environment. The present study was therefore undertaken to investigate the bioaccumulation of Manganese (Mn), Cobalt (Co), Mercury (Hg), Asernic (As), Chronium (Cr) and Nickel (Ni) in the muscle tissue of Cultured African Catfish (Clarias gariepinus). A total of two (2) fish were used (male and female) weighing 390g and 310g. They were sacrificed and all the internal organs were removed and was oven dried at initial temperature of 1050c and later adjust to 650c until a constant weight was obtained. The samples were grinded and were digested with tri acid mixture (HNO3: HCL: H2SO4). Digestion continued until the liquor become clear. The samples were analyzed using Dez Elmer Analyst 300 Atomic Spectroscopy (AAS). The result showed that Mn recorded 896.94±0.577mg/l; Co 78.10±0.577mg/l; and Ni, 78.725±0.578mg/l in feed 1 and Mn recorded 506.823±1.155mg/l; Co 32.499±0.577mg/l; Hg, 0.001±0.00001mg/l; As, 0.006±0.0000mg/l; Cr, 122.794±0.577mg/l. and Ni 56.180±0.578mg/l in feed 2. The result of the muscle tissue of male and female C.gariepinus shows the presence of heavy metals at different concentrations and the highest concentration was observed in female recorded Ni (44.200±0.5774mg/l) and the lowest observed in males recorded in Cr (-0.007±0.0001mg/l). There was a significant difference (P>0.05) among male and female C.gariepinus. This study has proved the availability of Mn, Co, Hg, As, Cr and Ni in the muscle tissue of C.gariepinus and also in the water and feeds used in culture the fish. This metal concentration observed in muscle tissue feeds and water was beyond the maximum permissible limit by WHO/FAO and NOAA for human consumption contrary to the most view that bioaccumulation of heavy metals is related to environmentally polluted water. Based on these findings, it is recommended that proper quality control analysis should be carried out in the cultured fish to determine its safety.

Title Changes in the Mineral Composition of Rat Femoral Bones Induced by Implantation of LNCaP Prostate Cancer Cells and Dietary Supplementation.

Prostate cancer (PCa) is the second most frequent cancer in men and the fifth most common cause of death worldwide, with an estimated 378,553 deaths in 2020. Prostate cancer shows a strong tendency to form metastatic foci in the bones. A number of interactions between cancer cells attacking bones and cells of the bone matrix lead to destruction of the bone and growth of the tumour. The last few decades have seen increased interest in the precise role of minerals in human health and disease. Tumour cells accumulate various minerals that promote their intensive growth. Bone, as a storehouse of elements, can be a valuable source of them for the growing tumour. There are also reports suggesting that the presence of some tumours, e.g., of the breast, can adversely affect bone structure even in the absence of metastasis to this organ. This paper presents the effect of chronic dietary intake of calcium, iron and zinc, administered in doses corresponding maximally to twice their level in a standard diet, on homeostasis of selected elements (Ca, K, Zn, Fe, Cu, Sr, Ni, Co, Mn and Mo) in the femoral bones of healthy rats and rats with implanted cancer cells of the LNCaP line. The experiment was conducted over 90 days. After the adaptation period, the animals were randomly divided into four dietary groups: standard diet and supplementation with Zn, Fe and Ca. Every dietary group was divided into experimental group (with implanted cancer cells) and control group (without implanted cancer cells). The cancer cells (LnCaP) were implanted intraperitoneally in the amount 1 × 106 to the rats at day 90 of their lifetime. Bone tissue was dried and treated with microwave-assisted mineral digestation. Total elemental content was quantified by ICP-MS. Student’s t-test and Anova or Kruskal–Wallis tests were applied in order to compare treatment and dietary groups. In the case of most of the diets, especially the standard diet, the femoral bones of rats with implanted LNCaP cells showed a clear downward trend in the content of the elements tested, which may be indicative of slow osteolysis taking place in the bone tissue. In the group of rats receiving the standard diet, there were significant reductions in the content of Mo (by 83%), Ca (25%), Co (22%), Mn (13%), K (13%) and Sr (9%) in the bone tissue of rats with implanted LNCaP cells in comparison with the control group receiving the same diet but without LNCaP implantation. Supplementation of the rat diet with calcium, zinc and iron decreased the frequency of these changes relative to the standard diet, which may indicate that the diet had an inhibitory effect on bone resorption in conditions of LNCaP implantation. The principal component analysis (PCA) score plot confirms the pronounced effect of implanted LNCaP cells and the standard diet on bone composition. At the same time, supplementation with calcium, zinc and iron seems to improve bone composition. The microelements that most often underwent quantitative changes in the experimental conditions were cobalt, manganese and molybdenum.

Manganese accumulation and tolerance in Eucalyptus globulus and Corymbia citriodora seedlings under increasing soil Mn availability

Manganese (Mn) is a nutrient that can cause phytotoxicity if above a threshold concentration. Acid soils are prone to excessive Mn levels that under certain environmental conditions may increase availability and exacerbate deleterious effects on plants. Apart from oxidative stress, excess Mn usually affects photosynthetic apparatus. Nonetheless, some plants are known to tolerate high Mn contents without negative consequences. We carried out a greenhouse experiment with two eucalypt species (Eucalyptus globulus and Corymbia citriodora), treated with four Mn additions in the soil substrate (0, 50, 150 and 300 mg kg−1) for 18 weeks. Before harvest, shoot height and the chlorophyll a fluorescence parameters were assessed, then leaves, stems and roots were sampled, weighted and nutrients determined. Manganese addition increased height for both species while biomass production remained unchanged, even though foliar concentrations ranged from 600 to 800 mg kg−1 at the highest Mn in soil. High root-to-shoot translocation of Mn was observed, yet—contrary to our hypothesis—photochemical efficiency of photosystem II was barely affected, except for the slight decrease in C. citriodora under 300 mg kg−1 Mn. The capacity to accumulate high Mn in photosynthetic tissues without chlorophyll damage seems to be a feature of Mn tolerant species. Nutritional imbalances such as magnesium decrease due to Mn exposure was observed, but not enough to cause deficiency. Both eucalypt species were therefore tolerant to high Mn concentrations in soil, especially E. globulus, and have the potential to be employed in reforestation/afforestation of lands with high risk of Mn phytotoxicity.

Pleiotropic ZIP8 A391T implicates abnormal manganese homeostasis in complex human disease.

ZIP8 is a metal transporter with a role in manganese (Mn) homeostasis. A common genetic variant in ZIP8 (rs13107325; A391T) ranks in the top 10 of pleiotropic SNPs identified in GWAS; A391T has associations with an increased risk of schizophrenia, obesity, Crohn’s disease, and reduced blood Mn. Here, we used CRISPR/Cas9-mediated knockin (KI) to generate a mouse model of ZIP8 A391T (Zip8 393T-KI mice). Recapitulating the SNP association with blood Mn, blood Mn was reduced in Zip8 393T-KI mice. There was restricted abnormal tissue Mn homeostasis, with decreases in liver and kidney Mn and a reciprocal increase in biliary Mn, providing in vivo evidence of hypomorphic Zip8 function. Upon challenge in a chemically induced colitis model, male Zip8 393T-KI mice exhibited enhanced disease susceptibility. ZIP8 391-Thr associated with reduced triantennary plasma N-glycan species in a population-based cohort to define a genotype-specific glycophenotype hypothesized to be linked to Mn-dependent glycosyltransferase activity. This glycophenotype was maintained in a cohort of patients with Crohn’s disease. These data and the pleiotropic disease associations with ZIP8 391-Thr suggest underappreciated roles of Mn homeostasis in complex human disease.

Ahtapotun (Octopus vulgaris) metal düzeylerinin değerlendirilmesi: sağlık riskleri tahmini

The levels of 13 different metals (Mg, P, K, Fe, Cu, Zn, Mn, Se, Al, Cr, As, Cd and Pb) in mantle and arm tissues of Octopus vulgaris species, which were caught from Mersin Bay in winter, spring and summer seasons, were determined. The results were compared between the tissues and seasons. Potential health risks of consumption of common octopus, which is an economically important species, were evaluated with the possibility that adult and child consumers will consume common octopus 1, 3 or 5 days a week. In this context, Estimated Weekly Intake Level (EWI), non-carcinogenic Target Hazard Quotient (THQ) and Lifetime Carcinogenic Risk (CR) were determined. Pb level was found to be above the limit level determined by FAO, EU and Turkish Food Codex. EWI values were found to be below the PTWI values determined by EFSA and FAO / WHO. THQ and ∑THQ values, which are indicative of non-cancer health risks for consumers, were determined as <1. In terms of carcinogenic risk, it was determined that these values (> 10-5) for As, Cr and Cd elements pose a carcinogenic risk to the consumer, but Pb values do not pose a risk.

St. Augustinegrass quality and nutrient content in response to granular and foliar iron, manganese, and magnesium

AbstractIron, manganese (Mn), and magnesium (Mg) are common components of turfgrass nutrition programs. A 2‐yr study was conducted simultaneously in Jay and Citra, FL, to determine the influence of Fe, Mn, and Mg on ‘Palmetto’ St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze.] quality and leaf nutrient concentration. Treatments included foliar Fe, Mn, and Mg sulfate and glucoheptonate; and granular Fe, Mn, and Mg sulfate and sucrate. Treatments were applied monthly from June to September during 2014 and 2015. Turfgrass receiving foliar Fe resulted in increased annual average turfgrass quality compared with untreated turfgrass in Citra during 2014 and in Jay during 2014 and 2015, which was associated with increased Fe in leaf tissue. Granular Mg did not influence turfgrass quality, whereas foliar Mg increased turfgrass quality by ∼10% during the last 4 wk of 2014 in Jay. Generally, foliar Mn did not influence turfgrass quality or tissue Mn concentrations, whereas granular Mn reduced turfgrass quality by ∼20% in Citra during 2015. Granular and foliar forms of Mn or Mg may not be warranted on turfgrass grown under similar conditions. Foliar Fe appears to be a reliable method of increasing St. Augustinegrass quality. Moreover, few differences were measured between foliar Fe sources, indicating that the least expensive foliar Fe source may be the most effective option for consumers. Evidence suggests that granular Fe does not improve turfgrass quality or tissue Fe concentrations and can therefore be removed from St. Augustinegrass nutritional programs without concerns of repercussions.

Heavy metal bioaccumulation, oxidative stress and genotoxicity in African catfish Clarias gariepinus from Orontes river.

One of the major problems affecting the ecosystem health is the exposure of heavy metals due to anthropogenic activities. These exposures may induce toxiogenetic damage and carcinogenesis in aquatic organism. DNA damage biomarkers for fish species detect genotoxic parameters for ecological risk assessment. In the present study, the effect of heavy metals (Cr, Cd, Cu, Fe and Mn) on DNA damage and oxidative stress of Clarias gariepinus was examined by Comet assay at Reference site and two different sampling sites of the Orontes River. Moreover, the relationship between DNA damage and physiological response to oxidative stress caused in C. gariepinus was investigated by sampling seasonal water and fish samples for one year. In this study, Cr, Cd and Cu in water column of Orontes River and the concentrations of Fe and Mn in liver tissue of C. gariepinus were highly exceed the maximum permissible limit set by EPA (1999, 2016) WHO (1989) and TEG (2012) that can cause adverse effects on environment health. SOD activities in liver tissues were significantly higher than those in muscle tissues. SOD, CAT activity and MDA levels of both Site 1 and Site 2 at Orontes River were higher than those of the Reference site. In result of the COMET analysis, the highest levels of DNA damage were found at gill and liver tissues in Site 2 (17.746 ± 1.072% T-DNA; 16.014 ± 0.710% T-DNA respectively) at Orontes river. A higher level of DNA damage in gill cells compared to liver cells was observed in all regions of the Orontes River. In Principal component analysis (PCA), the heavy metals Cd, Cr and Cu (in the water column) and MDA in liver and muscle revealed strong contribution to the observed DNA damage that were scattered opposite to each other's along the principal components. Moreover, correlations between parameters revealed a positive significant relationship between Cd, Cr and Cu in water and DNA damage levels in C. gariepinus. Pearson correlation analysis detected a positive relationship between MDA, CAT and SOD and DNA damage levels in African catfish. Consequently, this study exposed genotoxic damage and oxidative stress of C. gariepinus due to metal pollution in Orontes River and lead to the better understanding of genotoxicty, oxidative stress and heavy metal relationships.

Impacts of the Samarco Tailing Dam Collapse on Metals and Arsenic Concentration in Freshwater Fish Muscle from Doce River, Southeastern Brazil.

On November 2015, Samarco tailings dam in Mariana, Minas Gerais, Brazil, collapsed, releasing 62 million tons of tailings that advanced through 668 km of the Doce River and adjacent floodplain. Although the collapse was the worst environmental disaster in Brazil, little is known about its consequences to aquatic biota. Here we evaluate the effects of the tailings mudflow on metal and As concentration in fish and how concentration correlates with water and fish characteristics. We quantified semitotal amounts of Ag, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn in fish muscle tissue using inductively coupled plasma mass spectrometry (ICP-MS) in 255 individuals (34 species) sampled in unaffected and affected areas along the Doce River basin. Arsenic and Hg were higher in fish from affected sites, likely due to turbulent mixing of previously sedimented material by the giant tailings wave. Silver and Zn concentrations were higher in unaffected sites. Arsenic concentration in Geophagus brasiliensis decreased with increasing fish weight. Copper and Zn decreased with increasing fish weight considering the whole assembly of fish. The tailings mudflow increased water conductivity, and conductivity increased Al concentration in fish, so we expected a larger Al concentration in fishes from affected sites. However, the observed Al concentration in fishes from affected sites was lower than expected by water conductivity. Thus, the tailings mudflow reduced Al uptake or accumulation in fishes. Mercury decreased with increasing water conductivity in both unaffected and affected sites considering all species and in G. brasiliensis alone. Despite the relatively low concentration range of metals and As found in fish, fishes from sites affected by the Fe ore tailings mudflow showed higher As and Hg concentration, compared to fishes from unaffected sites. The higher As and Hg in affected sites require further detailed monitoring to ensure safeguards of human health by fishing activity along the Doce River. Integr Environ Assess Manag 2020;16:622-630. © 2020 SETAC.

The effect of manganese oxide nanoparticles on chicken growth and manganese content in excreta

Manganese in animal organisms is responsible for proper bone formation and many biochemical processes. The aim of the study was to determine the effect of manganese oxide nanoparticles (NanoMn2O3) as a mineral additive to the feed mixture on the growth, slaughter characteristics, femur bone strength, mineral content of tissues and Mn excretion. The male chickens were randomly divided between a control group without Mn2O3 in a premix, three groups receiving NanoMn2O3 (nano group 30, 60 and 100 % of the standard level) and three groups receiving Mn2O3 (30, 60 and 100 % of the standard level). Each group consisted of seven birds. The highest feed intake and body weight at 42 day was in the 60 % nano group, but there were no differences in the feed conversion rate. Slaughter characteristics, physicochemical properties, bone morphometry, the content of Mn in tissues and health status evaluated by blood parameters were not affected by supplying different forms of Mn2O3. Furthermore, the excretion of Mn was lower in NanoMn2O3 than in Mn2O3 groups. The results indicate that the application of NanoMn2O3 had no negative effects on chicken growth and development, but reduces Mn excretion, suggesting that commercial Mn2O3 can be replaced by NanoMn2O3 in broiler diets. However, follow-up research at farm conditions is necessary to validate the results.

Fly Ash and Compost Amendments and Mycorrhizal Inoculation Enhanced the Survival and Growth of Delonix regia in Cu-Ni Mine Tailings

Delonix regia, an ornamental tree that can tolerate an elevated level of heavy metals, was evaluated for phytoremediation potential in mine tailings with fly ash, compost, and mycorrhiza. A two-factorial experiment was conducted under screen house conditions using mine tailings from Bamangwato Concessions Limited (BCL) Cu-Ni mine. The treatments are mine tailing (MT) without mycorrhiza (MT – AM), MT with mycorrhiza (MT + AM), MT with 10% fly ash (FA) without mycorrhiza (MT + FA – AM), mine tailings with 10% FA with mycorrhiza (MT + FA + AM), MT with 10% compost (CP) without mycorrhiza (MT + CP – AM), and MT with 10% CP with mycorrhiza (MT + CP + AM). After 40 wk, results showed an interaction effect of amendments and mycorrhiza wherein compost and FA enhanced the survival, AM root colonization, plant height, and dry matter yield of D. regia seedlings. Mycorrhiza further enhanced these growth parameters, especially in pure mine tailings. The As, Cu, Mn, Ni, Pb, and Zn concentration in plant tissues were reduced substantially by FA and compost amendments. Mycorrhiza also reduced the As, Cu, Ni, Pb, and Zn in pure mine tailings but enhanced the concentration of these metals in the presence of FA and compost. These results could be attributed to the decrease of heavy metal availability and increase of nutrients due to FA and compost while mycorrhiza decreased the translocation of heavy metals regardless of the presence of FA and compost. Overall, results indicated that the survival and growth of D. regia in BCL Cu-Ni mine tailings could be enhanced by the combined application of fly ash, compost, and mycorrhiza.

Soil and Plant Analyses to Diagnose Hop Fields Irregular Growth

In cultivated fields, patches of poorly developed vegetation often appear without a clear indication of what is affecting the growth of the plants. The purpose of this study was to investigate the causes behind these irregularities in the hop (Humulus lupulus L.) fields of NE Portugal which are greatly reducing crop yield and farmers’ profits and to provide guidance to farmers as to appropriate remedial action. Patches of different levels of plant development were selected within hop fields and categorized according to plant vigour (weak, fair and good). Several soil properties were determined and related to the plant nutritional status and dry matter yield of different parts of the plant (hops, leaves, stems). Data was subjected to analysis of variance and principal component analysis. The results suggest that crop yield is reduced mostly due to poor soil aeration and excessive soil and tissue Mn and Fe levels. The plants from the plots of weaker vigour seem to be particularly affected by toxic levels of Mn and the plants from the plots of fair vigour by Fe levels. pH, texture (clay content), cation exchange capacity and organic carbon seem to be other soil properties with some degree of influence on plant performance. From these results, farmers are advised to increase soil aeration by implementing a drainage system and converting to a drip irrigation system, in addition to increasing soil pH by liming to reduce Mn toxicity.

Potential Effects of Heavy Metals Bioaccumulation on Oxidative stress Enzymes of Mediterranean clam Ruditapes decussatus

The bivalves have capability to accumulate the toxicant substances as heavy metals in their body tissues, therefore, they might be used as a good bio-indicators of water contamination. The present work aimed to measure the concentration of Cd, Cu, Pb, Mn, and Zn in the soft tissues of Ruditapes decussatus which collected between December 2018 and February 2019 from two sites of Mediterranean Sea. One from Alexandrian Port (Site I) and the other from Port Said (Site II), Egypt, as well as to estimate the potential physiological change of the clam affected by these pollutants. Samples from Site I gives comparatively higher water salinity and metals concentration in soft tissues. The statistical analysis shows significant increase in the level of malondialdehyde (MDA) while superoxide dismutase (SOD) and glutathione peroxidase were found decreased in the R. decussatus soft tissue collected from Site I. The correlation coefficient of physicochemical parameters, heavy metals and oxidative stress biomarkers in Site I shows that glutathione peroxidase and superoxide dismutase have positive correlation with acetylcholinesterase (r=0.912) and (r=0.929), respectively. SOD, on the other hand, was having negative correlation with MDA (r= -0.886). The reported values in this study are considered as basic data in monitor of the anthropogenic activities in future along the coast, as well as it is starter point in assessment of pollution that maybe effect on the aquatic organisms in the Mediterranean marine environment.

Potential Effects of Heavy Metals Bioaccumulation on Oxidative stress Enzymes of Mediterranean clam Ruditapes decussatus

The bivalves have capability to accumulate the toxicant substances as heavy metals in their body tissues, therefore, they might be used as a good bio-indicators of water contamination. The present work aimed to measure the concentration of Cd, Cu, Pb, Mn, and Zn in the soft tissues of Ruditapes decussatus which collected between December 2018 and February 2019 from two sites of Mediterranean Sea. One from Alexandrian Port (Site I) and the other from Port Said (Site II), Egypt, as well as to estimate the potential physiological change of the clam affected by these pollutants. Samples from Site I gives comparatively higher water salinity and metals concentration in soft tissues. The statistical analysis shows significant increase in the level of malondialdehyde (MDA) while superoxide dismutase (SOD) and glutathione peroxidase were found decreased in the R. decussatus soft tissue collected from Site I. The correlation coefficient of physicochemical parameters, heavy metals and oxidative stress biomarkers in Site I shows that glutathione peroxidase and superoxide dismutase have positive correlation with acetylcholinesterase (r=0.912) and (r=0.929), respectively. SOD, on the other hand, was having negative correlation with MDA (r= -0.886). The reported values in this study are considered as basic data in monitor of the anthropogenic activities in future along the coast, as well as it is starter point in assessment of pollution that maybe effect on the aquatic organisms in the Mediterranean marine environment.

Remediation of Cadmium-Polluted Soil Using Plant Growth-Promoting Rhizobacteria and Natural Zeolite

The impact of two strains of Pseudomonas bacteria and natural zeolite on the growth and elemental composition of barley plants was studied in an agrogray soil (Luvisol) artificially contaminated with cadmium in pot experiments. Application of P. fluorescens 21, or P. putida 23, or zeolite eliminated the heavy metal toxicity for plants. The cumulative effect of co-application of P. fluorescens 21 and zeolite was insignificant. The bacteria- or zeolite-mediated plant tolerance to cadmium was attributed to the enhanced root system development, decreased cadmium translocation into the roots, and improved mineral nutrition of the plants. Elevated nutrient uptake by the plants under the influence of bacteria and zeolite was the result of plant growth stimulation without significant changes in the concentrations of macronutrients N, P, K, Ca, and Mg, as well as Fe and micronutrients Zn, Mn, and Cu in plant tissues, including grain. Application of P. fluorescens 21 enhanced the Cd fixation in the soil organic matter in the first half of the growing season, which could be due to the metal sequestration by bacterial siderophores. Thus, application of the bacteria and natural zeolite can be recommended in the strategies for Cd-polluted soil remediation based on environment-friendly technologies.

Huntington's disease genotype suppresses global manganese-responsive processes in pre-manifest and manifest YAC128 mice.

Manganese (Mn) is an essential micronutrient required for the proper function of several enzymes. Accumulating evidence demonstrates a selective decrease of bioavailable Mn in vulnerable cell types of Huntington's Disease (HD), an inherited progressive neurodegenerative disorder with no cure. Amelioration of underlying pathophysiology, such as alterations in Mn-dependent biology, may be therapeutic. We therefore sought to investigate global Mn-dependent and Mn-responsive biology following various Mn exposures in a mouse model of HD. YAC128 and wildtype (WT) littermate control mice received one of three different Mn exposure paradigms by subcutaneous injection of 50 mg kg-1 MnCl2·4(H2O) across two distinct HD disease stages. "Pre-manifest" (12-week old mice) mice received either a single (1 injection) or week-long (3 injections) exposure of Mn or vehicle (H2O) and were sacrificed at the pre-manifest stage. "Manifest" (32-week old) mice were sacrificed following either a week-long Mn or vehicle exposure during the manifest stage, or a 20-week-long chronic (2× weekly injections) exposure that began in the pre-manifest stage. Tissue Mn, mRNA, protein, and metabolites were measured in the striatum, the brain region most sensitive to neurodegeneration in HD. Across all Mn exposure paradigms, pre-manifest YAC128 mice exhibited a suppressed response to transcriptional and protein changes and manifest YAC128 mice showed a suppressed metabolic response, despite equivalent elevations in whole striatal Mn. We conclude that YAC128 mice respond differentially to Mn compared to WT as measured by global transcriptional, translational, and metabolomic changes, suggesting an impairment in Mn homeostasis across two different disease stages in YAC128 mice.

Unprecedented Kinetic Inertness for a Mn2+ -Bispidine Chelate: A Novel Structural Entry for Mn2+ -Based Imaging Agents.

The search for more biocompatible alternatives to Gd3+ -based MRI agents, and the interest in 52 Mn for PET imaging call for ligands that form inert Mn2+ chelates. Given the labile nature of Mn2+ , high inertness is challenging to achieve. The strongly preorganized structure of the 2,4-pyridyl-disubstituted bispidol ligand L1 endows its Mn2+ complex with exceptional kinetic inertness. Indeed, MnL1 did not show any dissociation for 140 days in the presence of 50 equiv. of Zn2+ (37 °C, pH 6), while recently reported potential MRI agents MnPyC3A and MnPC2A-EA have dissociation half-lives of 0.285 h and 54.4 h under similar conditions. In addition, the relaxivity of MnL1 (4.28 mm-1 s-1 at 25 °C, 20 MHz) is remarkable for a monohydrated, small Mn2+ chelate. In vivo MRI experiments in mice and determination of the tissue Mn content evidence rapid renal clearance of MnL1 . Additionally, L1 could be radiolabeled with 52 Mn and the complex revealed good stability in biological media.

Unprecedented Kinetic Inertness for a Mn2+‐Bispidine Chelate: A Novel Structural Entry for Mn2+‐Based Imaging Agents

AbstractThe search for more biocompatible alternatives to Gd3+‐based MRI agents, and the interest in 52Mn for PET imaging call for ligands that form inert Mn2+ chelates. Given the labile nature of Mn2+, high inertness is challenging to achieve. The strongly preorganized structure of the 2,4‐pyridyl‐disubstituted bispidol ligand L1 endows its Mn2+ complex with exceptional kinetic inertness. Indeed, MnL1 did not show any dissociation for 140 days in the presence of 50 equiv. of Zn2+ (37 °C, pH 6), while recently reported potential MRI agents MnPyC3A and MnPC2A‐EA have dissociation half‐lives of 0.285 h and 54.4 h under similar conditions. In addition, the relaxivity of MnL1 (4.28 mm−1 s−1 at 25 °C, 20 MHz) is remarkable for a monohydrated, small Mn2+ chelate. In vivo MRI experiments in mice and determination of the tissue Mn content evidence rapid renal clearance of MnL1. Additionally, L1 could be radiolabeled with 52Mn and the complex revealed good stability in biological media.

Effect of cage culture environment on farmed fish in terms of metal accumulation

Metal pressure under farm conditions was examined on the gill and muscle tissues of farmed Sparus aurata and compared with their wild counterparts (Sparus aurata, Trachurus trachurus, Mullus barbatus). Al, Mn, Cd, Co, Cr, Cu, Ni, Pb and Zn accumulation amounts in gill tissue of farmed fish were 28.821, 37.620, 0.136, 0.300, 3.730, 2.441, 3.222, 2.474 and 127.494 mg/kg respectively. Among them, Cd, Cr, Cu and Pb concentrations in gill tissue of farmed fish were higher than that in wild fishes. Metal depositions in muscle tissue of farmed fish were far below that in the gill tissue. The accumulated Al (6.700 mg/kg) in the muscle tissue of farmed fish was higher than in wild ones. The results showed that metal accumulation levels (especially Cd, Cr, Cu and Pb) in the gill tissue of farmed fish indicate metal pressure under captive conditions. Furthermore, the calculated hazard index (HI) and total hazard index (THI) of the considered elements in the edible part of farmed fish were below the level considered safe, which elucidates that farmed fish do not pose any threat to the human consumer in terms of metal toxicity.

Essential trace elements in placental tissue and risk for fetal neural tube defects

This study examined the associations between concentrations of cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se), and zinc (Zn) in placental tissue and risks for NTDs with a case-control design consisting of 408 fetuses or newborns with neural tube defects (NTDs) and 593 non-malformed fetuses or newborns. The concentrations of Zn and Fe were determined by inductively coupled plasma-emission spectrometer and the other four elements by inductively coupled plasma-mass spectrometer. Element concentrations were presented in ng/g or µg/g dry weight of placental tissue. The associations between the levels of each of the six ETEs and risk for NTDs were evaluated using multivariable logistic regression, and the associations between overall levels of all six ETEs and risk for NTDs were examined using Bayesian kernel machine regression (BKMR). Concentrations above the median concentration of all participants for an individual element were associated with increased risk for NTDs: Mn, 3.17-fold (95% CI 2.35–4.28); Mo, 3.73-fold (95% CI 2.74–5.07); Se, 3.28-fold (95% CI 2.44–4.42); and Zn, 2.85-fold (95% CI 2.13–3.83), and a decreased risk for Co [OR, 0.18 (95% CI 0.14–0.25)]. The risk for NTDs increased with the increase in the concentrations of Mn, Mo, Se, and Zn, but decreased for Co, in the second, third, and fourth quartiles, respectively, compared to their lowest quartile (all Pstrend < 0.01). In BKMR model, the risk for NTDs increased constantly when the overall exposure levels were higher than the median of the six ETEs as a co-exposure mixture, and the associations between Co, Mn, Se, and Zn and NTD risk remained when the remaining five elements were taken into consideration simultaneously. Taken together, when evaluated individually, higher levels of Mn, Se, and Zn in placental tissue are associated with increased risk for NTDs, while higher levels of Co are associated with decreased risk for NTDs; when examined collectively, the risk of NTDs increases continuously when exposure levels are higher than the median of the six ETE mixture.