High Levels Of Manganese Research Articles

Growth and Ethylene Production in Eucalyptus Clones Sensitive to Shoot Blight, Submitted to Hypoxia and High Levels of Manganese

Eucalyptus shoot blight in the Rio Doce Valley (ESBVRD) is a physiological anomaly that has been related to hypoxic environment and Mn excess. This study had the objective of understanding the mechanisms involved in the differential tolerance of eucalyptus clones to ESBVRD. Two experiments were carried out: (I) two clones, a sensitive and a ESBVRD tolerant, two O2 concentrations (normal and hypoxic) and five concentrations of Mn (0, 5, to 90 mg L-1); (II) same two eucalyptus clones, two O2 concentrations (normal and mild hypoxic) and two Mn concentrations (30 and 300 mg L-1). The hypoxic condition reduced the plant dry weight and increased the production of ethylene in the two clones, both more strikingly in the sensitive clone. The O2 deficiency was the first factor predisposing the clones to ESBVRD, in contrast to Mn excess, that appeared to act over a longer period for the expression of the symptoms.

Study of Groundwater in Northeast Cairo Area, Egypt

This paper presents a comprehensive hydrogeologic view of the Quaternary aquifer in north eastern Cairo area, Egypt. The hydrogeologic, hydrochemical and isotopic features of the aquifer are determined to assess the groundwater geochemistry and quality for different uses. The groundwater in the aquifer is shallow and flows towards the heavily pumping areas (cultivated and industrial areas). The concentrations of total dissolved solids (TDS) vary considerably in the aquifer, ranging from 225.6 mg/L to 1219 mg/L. Wide variations in the concentrations of major ions, trace elements, nitrate, δ18O and δ2H are detected, indicating the variation in the geologic and recharge conditions. This further indicates the effect of natural processes (weathering, dissolution and ion exchange) as well as anthropogenic activities on the quality of groundwater. Moderate levels of contamination with nitrate, aluminum and manganese are recorded in the groundwater below the cultivated area. The contamination is linked to the extensive use of fertilizers for agriculture and the leakage of wastewater from improper sewage system. The computed nitrate pollution index reveals that about 69.69% of groundwater is safe for drinking, while the rest of groundwater is unsuitable. The calculated water quality index indicates that about 78.79% of groundwater is safe for human consumption and the rest of groundwater is poor for consumption because of the contamination with the high levels of manganese, total hardness, pH, sulphate, aluminum, and nitrate. The contaminated groundwater needs to be treated before consumption. Hence, periodic groundwater quality checks are recommended.

Effect of superoxide dismutase and manganese on superoxide tolerance in Lactobacillus casei strain Shirota and analysis of multiple manganese transporters.

The Lactobacillus casei/paracasei group accumulates a high level of manganese, which works to scavenge superoxide anions produced during aerobic growth. The genome of L. casei strain Shirota, however, also codes the gene for superoxide dismutase (SOD), sodA, which catalyzes the dismutation of superoxide anion into hydrogen peroxide and oxygen. We anticipated that the SOD and/or manganese may contribute to the aerobic growth of L. casei Shirota and tried to clarify how L. casei Shirota can eliminate the toxicity of superoxide anion. When the sodA of L. casei Shirota was cloned and expressed in Escherichia coli as well as in L. casei Shirota, there was no increase in SOD activity detected, meaning that the protein is in an inactive form, even if it is produced in L. casei Shirota. We next focused on the role of the manganese transport system of L. casei Shirota. One ABC-type manganese transporter (mtsCBA cluster) and three NRAMP-type manganese transporters (mntH1, mntH2, and mntH3) are coded in the genome. To clarify the role of these genes, we disrupted one or more of these manganese transporter genes in different combinations and analyzed the intracellular manganese levels. As a result, we found that NRAMP-type manganese transporters coded by mntH1 and mntH2 and ABC-type manganese transporter coded by mtsCBA cluster are complementarily involved in the accumulation of intracellular manganese and are necessary for aerobic growth of L. casei Shirota. These results indicate that intracellular manganese accumulated by multiple complementary manganese transporters, but not SOD, plays a pivotal role in tolerance to superoxide in L. casei Shirota.

Terras pretas: Approaches to formation processes in a new paradigm

AbstractTerras pretas (Amazonian Dark Earths) are a remarkable kind of archaeological site found in the Amazon region. Rich in cultural artifacts and other occupational debris, these dark anthropogenic soil matrices are very fertile, presenting high levels of organic carbon, phosphorus, calcium, magnesium, zinc, and manganese. Their high nutrient levels come from decomposed organic matter, including remains of fish, shellfish, game, and other refuse, while their dark color has been linked to residual charcoal from intentional fires associated with daily activities and landscape management. Studies of anthropogenic earths in the Amazon have a deep history, as much in the geosciences as in archaeology and other historical sciences. Terras pretas have been studied as evidence of a major shift in human–environment relations, but also within the lens of environmental resiliency and sustainability. We review representative studies from various disciplinary fields and trace the development of knowledge about terra preta. We present a growing consensus with regard to the origin and significance of anthropogenic soils, concomitant with increased efforts toward interdisciplinary study. We argue that terras pretas constitute a genuinely interdisciplinary research topic that bridges scientific and traditional knowledge and applied contexts.

Hypothyroidism induced by loss of the manganese efflux transporter SLC30A10 may be explained by reduced thyroxine production

SLC30A10 and SLC39A14 are manganese efflux and influx transporters, respectively. Loss-of-function mutations in genes encoding either transporter induce hereditary manganese toxicity. Patients have elevated manganese in the blood and brain and develop neurotoxicity. Liver manganese is increased in patients lacking SLC30A10 but not SLC39A14. These organ-specific changes in manganese were recently recapitulated in knockout mice. Surprisingly, Slc30a10 knockouts also had elevated thyroid manganese and developed hypothyroidism. To determine the mechanisms of manganese-induced hypothyroidism and understand how SLC30A10 and SLC39A14 cooperatively mediate manganese detoxification, here we produced Slc39a14 single and Slc30a10/Slc39a14 double knockout mice and compared their phenotypes with that of Slc30a10 single knockouts. Compared with wild-type controls, Slc39a14 single and Slc30a10/Slc39a14 double knockouts had higher manganese levels in the blood and brain but not in the liver. In contrast, Slc30a10 single knockouts had elevated manganese levels in the liver as well as in the blood and brain. Furthermore, SLC30A10 and SLC39A14 localized to the canalicular and basolateral domains of polarized hepatic cells, respectively. Thus, transport activities of both SLC39A14 and SLC30A10 are required for hepatic manganese excretion. Compared with Slc30a10 single knockouts, Slc39a14 single and Slc30a10/Slc39a14 double knockouts had lower thyroid manganese levels and normal thyroid function. Moreover, intrathyroid thyroxine levels of Slc30a10 single knockouts were lower than those of controls. Thus, the hypothyroidism phenotype of Slc30a10 single knockouts is induced by elevated thyroid manganese, which blocks thyroxine production. These findings provide new insights into the mechanisms of manganese detoxification and manganese-induced thyroid dysfunction.

Shiraz (Vitis vinifera L.) Berry and Wine Sensory Profiles and Composition Are Modulated by Rootstocks

Sensory and compositional measures were conducted on berries and wines of Vitis vinifera L. cv Shiraz vines grown on own roots or grafted to three different rootstocks. The study was conducted in an experimental rootstock vineyard in the Barossa Valley, South Australia during two growing seasons (2009/2010 and 2010/2011). Wines produced from fruit from vines grown on their own roots were characterized by red berry aroma, whereas wines produced using grapes grown on vines grafted to either 110 Richter or Schwarzmann rootstocks had a darker rim and more intense body color, dark berry aroma, and red berry flavor, as well as more intense and coarser tannins. Juice and wines from rootstock treatments had higher levels of manganese, magnesium, and boron, while sodium level was higher in juice and wines produced from vines grown on their own roots. The majority of the acetate esters were higher in the wines made from vines on their own roots in both seasons. The highest wine quality scores were obtained by 110 Richter wines and the lowest by wines from own-roots treatment in both seasons. Differences in fruit exposure (moderated by rootstock) may affect fruit composition and sensory results and remains to be clarified. This study demonstrated that the use of rootstocks can have a positive effect on wine composition, sensory properties, and wine quality.

Ovarian hyperandrogenism in polycystosis which is associated with stress caused by exposure of manganese and nickel

Objective. High concentrations of manganese and nickel in the serum of women with polycystic ovary syndrome (PCOS) have been detected in our previous studies. The aim of this investigation was to study the features of the adrenal hormones metabolism in women with polycystic ovarian syndrome (PCOS) with a high level of manganese and nickel exposure. Material and Methods . Two groups of women were formed for study. The first group consisted of women with PCOS. Patients with Cushing's syndrome were not included in this group. The second group – control group, consisted of healthy women of reproductive age. Serum total testosterone (T), dehydroepiandrosterone sulfate (DHEAS), dihydrotestosterone (DHT), 17-hydroxyprogesterone (17-OP), cortisol (C) were identified using ELISA in the early follicular phase. Statistical analysis of the results was performed using Student's test and Mann-Whitney. Results . Women with PCOS had enhanced levels of all studied hormones and metabolites in serum in comparison with the control group (P <0,05). An analysis of reference values frequency exceeding was done. Results showed that most often there was an increase in 17-OP level in 60.0% of cases and DHEAS in 52.38% of cases. Since 17-OP is not synthesized in the ovaries of women with PCOS, we assume that its synthesis is associated with activation of adrenal function. 17-ОР is a precursor for the synthesis of cortisol and androgens. According to the authors, adrenal function activation is associated with stress caused by manganese and nickel toxic concentrations. Cortisol relates to hormonal markers of stress. Women with PCOS had increased levels of C in 30.56%. In conditions of manganese and nickel increased level exposure determining of 17-OP can be useful in the diagnosis of hyperandrogenism. Conclusions . Significantly increased levels of hormones and metabolites predominantly of adrenal origin have been noted in women with PCOS. Revealed violations could be a manifestation of hormonal stress caused by toxic effects of manganese and nickel and are a protective mechanism of organism adaptation to adverse conditions. The process of adaptation to environmental stress is accompanied by dysfunction of the hypothalamic-pituitary-adrenal system.

Use of portable X-ray fluorescence in the analysis of surficial sediments in the exploration of hydrothermal vents on the Southwest Indian Ridge

Hydrothermal plumes released from the eruption of sea floor hydrothermal fluids contain large amounts of oreforming materials. They precipitate within certain distances from the hydrothermal vent. Six surficial sediment samples from the Southwest Indian Ridge (SWIR) were analyzed by a portable X-ray fluorescence (PXRF) analyzer on board to find a favorable method fast and efficient enough for sea floor sulfide sediment geochemical exploration. These sediments were sampled near, at a moderate distance from, or far away from hydrothermal vents. The results demonstrate that the PXRF is effective in determining the enrichment characteristics of the oreforming elements in the calcareous sediments from the mid-ocean ridge. Sediment samples (>40 mesh) have high levels of elemental copper, zinc, iron, and manganese, and levels of these elements in sediments finer than 40 mesh are lower and relatively stable. This may be due to relatively high levels of basalt debris/glass in the coarse sediments, which are consistent with the results obtained by microscopic observation. The results also show clear zoning of elements copper, zinc, arsenic, iron, and manganese in the surficial sediments around the hydrothermal vent. Sediments near the vent show relatively high content of the ore-forming elements and either high ratios of copper to iron content and zinc to iron content or high ratios of copper to manganese content and zinc to manganese content. These findings show that the content of the ore-forming elements in the sediments around hydrothermal vents are mainly influenced by the distance of sediments to the vent, rather than grain size. In this way, the PXRF analysis of surface sediment geochemistry is found to satisfy the requirements of recognition geochemical anomaly in mid-ocean ridge sediments. Sediments with diameters finer than 40 mesh should be used as analytical samples in the geochemical exploration for hydrothermal vents on mid-oceanic ridges. The results concerning copper, zinc, arsenic, iron, and manganese and their ratio features can be used as indicators in sediment geochemical exploration of seafloor sulfides.

The Joint Effect of Prenatal Exposure to Metal Mixtures on Neurodevelopmental Outcomes at 20-40 Months of Age: Evidence from Rural Bangladesh.

Background:Exposure to chemical mixtures is recognized as the real-life scenario in all populations, needing new statistical methods that can assess their complex effects.Objectives:We aimed to assess the joint effect of in utero exposure to arsenic, manganese, and lead on children’s neurodevelopment.Methods:We employed a novel statistical approach, Bayesian kernel machine regression (BKMR), to study the joint effect of coexposure to arsenic, manganese, and lead on neurodevelopment using an adapted Bayley Scale of Infant and Toddler Development™. Third Edition, in 825 mother–child pairs recruited into a prospective birth cohort from two clinics in the Pabna and Sirajdikhan districts of Bangladesh. Metals were measured in cord blood using inductively coupled plasma-mass spectrometry.Results:Analyses were stratified by clinic due to differences in exposure profiles. In the Pabna district, which displayed high manganese levels [interquartile range (IQR): 4.8, ], we found a statistically significant negative effect of the mixture of arsenic, lead, and manganese on cognitive score when cord blood metals concentrations were all above the 60th percentile (, , ) compared to the median (, , ). Evidence of a nonlinear effect of manganese was found. A change in log manganese from the 25th to the 75th percentile when arsenic and manganese were at the median was associated with a decrease in cognitive score of (, ) standard deviations. Our study suggests that arsenic might be a potentiator of manganese toxicity.Conclusions:Employing a novel statistical method for the study of the health effects of chemical mixtures, we found evidence of neurotoxicity of the mixture, as well as potential synergism between arsenic and manganese. https://doi.org/10.1289/EHP614

Derivation of an occupational exposure level for manganese in welding fumes

Exposure to high levels of manganese (Mn) in occupational settings is known to lead to adverse neurological effects. Since Mn is an essential nutrient, there are mechanisms that maintain its homeostatic control in the body, and there is some level of Mn in air that does not perturb Mn homeostasis. However, the Mn exposure concentrations at which no adverse effects are expected in occupational settings vary considerably across regulatory agencies. We set out to derive a Mn Occupational Exposure Level (OEL) for welders based on a review of studies that evaluated Mn exposure concentrations from welding fumes and: (1) neurological effects in welders; (2) levels of Mn in the brains of welders (via pallidal index [PI] estimated from magnetic resonance imaging [MRI]); (3) other biomarkers of Mn exposure in welders (i.e., blood and urine); and (4) Mn brain concentrations, PI, and corresponding neurological effects in non-human primates. Our analysis suggests uncertainty in quantifying dose-response associations for Mn from many of the occupational welding studies. The few welding studies that adequately estimate exposure suggest a possible OEL of 100–140μg/m3 for respirable Mn. This range is consistent with other epidemiology studies, studies of biomarkers of Mn exposure in welders, and with studies in non-human primates, though future studies could provide a stronger basis for deriving a Mn occupational guideline for welders.

Evaluation of Trace Elements in Iraqi Patients with Rheumatoid Arthritis by using Atomic Absorption Spectrophotometer (AAS)

Zinc, Copper, Selenium, Magnesium, Manganese, Chromium, Iron, Nickel, Cobalt, Vanadium and Germanium were determined by atomic absorption spectrophotometer (AAS) in blood serum of patients with rheumatoid arthritis, (30) patients (14male and 16female) with age range (37-60) years compared with normal tensive control. The analysis of results showed that the mean value of concentration (Magnesium, Manganese and Nickel) were significantly higher in patients with rheumatoid arthritis compared to that of healthy, while the mean levels of serum (Zinc, Copper, Selenium, Chromium, Iron, Cobalt and Germanium) were significantly lower than controls. There were no significant changes in overall mean concentration of serum Vanadium in patients with rheumatoid arthritis and control group. There were no significant variations in trace elements levels in relation to sex.Our results suggest that low level of trace elements of Zinc, Copper, Selenium, Chromium, Iron, Cobalt and Germanium , and high levels of Magnesium, Manganese and Nickel may provide good clues to the physician about the high probability of the individual for developing of rheumatoid arthritis disease unless the imbalance of these elements in blood serum to be corrected.&#x0D; Key words: Trace elements, Rheumatoid arthritis,Atomic absorption spectrophotometer (AAS).

Survey on Metals Contained in Stainless Steel Kitchenware and Tableware.

Stainless steel kitchenware and tableware on sale in Japan were investigated. Surface elemental composition ratios of 172 samples were analyzed by the fluorescence X-ray method. High levels of manganese (9.59-20.03%)were detected in 17 samples. This finding was confirmed by ICP analysis. Next, we conducted migration tests. Samples conformed to the Italian Specific Migration Limits. Moreover, lead and antimony were not detected in these samples, in accordance with the Japanese Food Sanitation Law.

Preliminary Data on the Interaction between Some Biometals and Oxidative Stress Status in Mild Cognitive Impairment and Alzheimer's Disease Patients.

Increased interest regarding the biometal mechanisms of action and the pathways in which they have regulatory roles was lately observed. Particularly, it was shown that biometal homeostasis dysregulation may lead to neurodegeneration including Alzheimer's disease, Parkinson disease, or prion protein disease, since important molecular signaling mechanisms in brain functions implicate both oxidative stress and redox active biometals. Oxidative stress could be a result of a breakdown in metal-ion homeostasis which leads to abnormal metal protein chelation. In our previous work, we reported a strong correlation between Alzheimer's disease and oxidative stress. Consequently, the aim of the present work was to evaluate some of the biometals' levels (magnesium, manganese, and iron), the specific activity of some antioxidant enzymes (superoxide dismutase and glutathione peroxidase), and a common lipid peroxidation marker (malondialdehyde concentration), in mild cognitive impairment (n = 15) and Alzheimer's disease (n = 15) patients, compared to age-matched healthy subjects (n = 15). We found increased lipid peroxidation effects, low antioxidant defense, low magnesium and iron concentrations, and high manganese levels in mild cognitive impairment and Alzheimer's disease patients, in a gradual manner. These data could be relevant for future association studies regarding the prediction of Alzheimer's disease development risk or circling through stages by analyzing both active redox metals, oxidative stress markers, and the correlations in between.

Biological activities and secondary compound composition from Crithmum maritimum aerial parts

ABSTRACTThis study aimed to assess the biological activities and secondary compound composition from Algerian Crithmum maritimum and, therefore, to better characterize local medicinal plants. The aerial parts were investigated regarding their mineral, antioxidant and essential oil content, and composition. The C. maritimum aerial parts contained high levels of potassium, calcium, manganese, and iron. The phenolic fraction was composed by at least 10 identified hydroxycinnamic acids that exhibited scavenging activity against DPPH and ABTS+. Moreover, the C. maritimum essential oil had a strong antimicrobial activity. The essential oil was composed by a least 10 molecules comprising monoterpene hydrocarbons and oxygenated monoterpenes.

442 - Oxidative Stress Induced by Formation of the Peroxidase FeSOD2 in Mitochondria of Cells

Cellular aerobic respiration leads to the production of potentially deleterious reactive by-products such as the free radical superoxide anion (O2●–). Organisms have superoxide dismutases (SODs) to catalyze the conversion of O2●– to H2O2 and molecular oxygen. Superoxide dismutase 2 (SOD2) is a mitochondrial-resident protein essential for organisms to be able to cope with oxygen respiration. Even though SOD2 is primarily considered a cellular antioxidant enzyme, higher levels of this enzyme in some cells and tissues have been shown to be prooxidant and responsible for mitochondrial dysfunction. Here we explain this discrepancy by showing that the manganese-dependent SOD2 when alternatively incorporated with iron displays a prooxidant peroxidase activity, a gain of function that enables this enzyme to utilize H2O2 to oxidize other molecules. Human SOD2 incorporated with manganese (MnSOD2) displays negligible peroxidase activity in vitro, but a switch from manganese to iron (FeSOD2) promotes the prooxidant peroxidase activity while preventing its capacity to function as an antioxidant. We detected the formation of FeSOD2 in human cells that overexpress this protein. Human cells with FeSOD2 showed detrimental changes in mitochondrial function and gene expression profile, and showed a shift in metabolism from oxidative phosphorylation to glycolysis. They had higher synthesis of mitochondrial proteins, even though they did not show changes in mitochondrial mass, which suggests mitochondrial instability and dysfunction. Even more important, those cells showed higher susceptibility to oxidative stress induced by H2O2 or paraquat exposure. The formation of FeSOD2 in mitochondria could be prevented by cultivating cells with higher levels of manganese in the medium. The ratio of iron to manganese in combination with the level of SOD2 in cells is shown to be essential to determine the fate of SOD2 as an antioxidant or a prooxidant. Occurrence of this fundamental antioxidant enzyme in a prooxidant state when incorporated with iron represents an important biological source of free radical generation since formation of FeSOD2 impacts mitochondrial function, changes cellular bioenergetics and decreases overall cellular resistance to oxidative stress. Formation of FeSOD2 might be implicated in disease development in humans since higher levels of iron and SOD2 are commonly observed in diseases related to oxidative stress.

Comparative studies on nutrient profiling of two deep sea fish (Neoepinnula orientalis and Chlorophthalmus corniger) and brackish water fish (Scatophagus argus)

Extensive researches are in progress to explore the deep sea resources in our planet to conquer the dilemma and diminish the size of malnourished community. Nowadays the limelight has been broadened toward the deeper ocean. In the present study the nutrient profiling of two deep sea fish species (Neoepinnula orientalis and Chlorophthalmus corniger) was compared with a well-known edible brackish water fish (Scatophagus argus). The deep sea fish of interest (N. orientalis and C. corniger) were observed to possess relatively similar quantities of crude protein (18.6±0.9 and 19.4±0.9% respectively) as that of S. argus (20.4±0.8%). The fat content of N. orientalis is commensurate with that of spotted scat, whereas C. corniger was found to contain very high fat content (14.6±0.7%). Though their amino acid composition display slight variation with that of the brackish water fish, the deep sea fish were analyzed to contain significant amount of the essential amino acids viz. lysine, phenyl alanine, histidine, as well as the non essential amino acids aspartate, arginine, serine, glutamate, proline, glycine, alanine. The studies have also conceded that the fish from deep waters are the comparable sources of minerals, with those of the brackish water fish. Among the three fish of interest N. orientalis was noticed to be the richest source of sodium (5746±27mgkg−1), potassium (3438±19mgkg−1), calcium (4247±16mgkg−1) and magnesium (2253±21mgkg−1). Meanwhile, C. corniger is having highest levels of iron (120±1.5mgkg−1) and zinc (135±2.8mgkg−1), whereas S. argus was found to have the highest levels of manganese (35.8±2.8mgkg−1) and nickel (10.1±0.8mgkg−1). The level of cadmium in N. orientalis (0.75±0.01mgkg−1) was demonstrated to be slightly higher than the prescribed limit. The present study has revealed that both deep sea fish of interest exhibit an analogous nutritive value with that of the common edible brackish water fish, S. argus.

Determination of the inorganic composition and short term effect of aqueous extracts of root, pod, and stem of Telfairia occidentalis on some hematological parameters in rats

Aims and Objectives: This study is to investigate the inorganic composition and the effect of fourteen (14) -day oral administration of aqueous extracts of root, pod and stem of Telfairia occidentalis in rats.Materials and Methods: Plant samples were analyzed for K, P, Mg, Ca, S, Mn, Fe, Cu, Zn, Pb, and Cr using atomic absorption spectrophotometry (AAS). Wister rats of both sexes were assigned to sixteen (16) groups of 4 animals per group. Different animal groups received distilled water and root, stem, and pod extracts at the doses of 250, 750, 1500, 2250, and 3000mg/kg of body weight. All animals were treated for 14 days and sacrificed on the 15th day.Results: The inorganic composition result showed that potassium (K) was the highest in abundance in all the samples (root, pod, and stem), compared to the other mineral elements. The root contained high levels of potassium and manganese; the stem had magnesium, manganese and iron while the pod contained high amount of potassium, manganese and iron. Hematological assay results showed reduction in the values of white blood cell (WBC) count for higher doses of root extract and all doses (except for 1500mg/kg bw) of pod extract. Platelet count (PLT) was significantly high for root extract at 750mg/kg bw. The stem extract showed a consistent decrease in the red blood cell (RBC) count for all dose administered.Conclusion: Telfairia occidentalis root, pod, and stem may be a good source of inorganic elements. The extracts have varying effects on hematological parameters which may be dosage- and duration- dependent.Asian Journal of Medical Sciences Vol.7(5) 2016 75-80

The association of prenatal metals exposure with children’s growth in Bangladesh

Introduction: Arsenic, lead, and manganese are all known health hazards. However, most information of these metals exposure come from studies on adults. The effects of exposure to metals during fetal life and later growth and development still remain uncertain. This is one area that urgently need exploring with major public health implications. In this study, we seek to characterize the association of prenatal metals exposure with childhood growth parameters. Methods: Study population was taken from 819 women recruited between 2004 and 2011 in Bangladesh. Height and weight measurements were taken at birth, 12 months and again between 24-36 months. Umbilical cord blood measurements were collected at the time of delivery and analyzed via ICP-MS. The association between prenatal metals exposure and child height and weight was investigated using multivariate linear and mixed models. Results: In this study, we showed that, among the three cord blood metals tested, early arsenic (As) exposure had the strongest and most consistent inverse association with infant parameters of birth weight (beta=-0.13 kg +/- 0.05 kg) and birth height (beta=-0.09 cm +/-0.06 cm). Manganese (Mn) also indicated statistically significant inverse relationship with birth height, however only at higher quartile levels compared to the reference. There is inverse association found with child height changes up to 36 months of age due to early exposure to arsenic (beta= =- 0.14 cm +/- 0.08 cm) and at high levels of manganese (Mn: beta=-0.09cm, p=0.05 at highest quartile). No association has been apparent with Lead. Conclusion: Results indicate that prenatal arsenic and manganese exposure adversely affect child height and weight development at birth and up to 36 months of age.

Identification and Characterization of a Putative Manganese Export Protein in Vibrio cholerae

Manganese plays an important role in the cellular physiology and metabolism of bacterial species, including the human pathogen Vibrio cholerae The intracellular level of manganese ions is controlled through coordinated regulation of the import and export of this element. We have identified a putative manganese exporter (VC0022), named mneA (manganese exporter A), which is highly conserved among Vibrio spp. An mneA mutant exhibited sensitivity to manganese but not to other cations. Under high-manganese conditions, the mneA mutant showed an almost 50-fold increase in intracellular manganese levels and reduced intracellular iron relative to those of its wild-type parent, suggesting that the mutant's manganese sensitivity is due to the accumulation of toxic levels of manganese and reduced iron. Expression of mneA suppressed the manganese-sensitive phenotype of an Escherichia coli strain carrying a mutation in the nonhomologous manganese export gene, mntP, further supporting a manganese export function for V. cholerae MneA. The level of mneA mRNA was induced approximately 2.5-fold after addition of manganese to the medium, indicating regulation of this gene by manganese. This study offers the first insights into understanding manganese homeostasis in this important pathogen. Bacterial cells control intracellular metal concentrations by coordinating acquisition in metal-limited environments with export in metal-excess environments. We identified a putative manganese export protein, MneA, in Vibrio cholerae An mneA mutant was sensitive to manganese, and this effect was specific to manganese. The mneA mutant accumulated high levels of intracellular manganese with a concomitant decrease in intracellular iron levels when grown in manganese-supplemented medium. Expression of mneA in trans suppressed the manganese sensitivity of an E. coli mntP mutant. This study is the first to investigate manganese export in V. cholerae.

U-Shaped Association between Plasma Manganese Levels and Type 2 Diabetes.

Background:Manganese is both an essential element and a known toxicant, and it plays important roles in many mechanisms in relation to type 2 diabetes (T2D). However, epidemiological studies of this relationship are rare.Objective:We investigated the association between plasma manganese and newly diagnosed T2D as well as whether the association could be modified by manganese superoxide dismutase (MnSOD) polymorphisms.Methods:We conducted a case–control study of 3,228 participants in China: 1,614 T2D patients and 1,614 controls. Concentrations of plasma magnesium were measured, and all participants were genotyped for the MnSOD Val16Ala polymorphism (rs4880).Results:A U-shaped association was observed between plasma manganese and T2D, with increased odds ratios (ORs) in relation to either low or high plasma manganese levels. Compared with the middle tertile, the multivariate-adjusted ORs [95% confidence intervals (CIs)] of T2D associated with the lowest tertile and the highest tertile of plasma manganese were 1.89 (1.53, 2.33) and 1.56 (1.23, 1.97), respectively. In spline analysis, the U-shaped association was consistently indicated, with the lowest odds of T2D at the plasma manganese concentration of 4.95 μg/L. Minor allele frequencies (C allele) of the MnSOD Val16Ala polymorphism (rs4880) in the normal glucose tolerance (NGT) and the T2D groups were 13.57% and 14.50%, respectively. The MnSOD rs4880 polymorphism was not associated with T2D, and no interaction was found between plasma manganese and the MnSOD rs4880 polymorphism in relation to T2D.Conclusions:Our results suggested a U-shaped association between plasma manganese and T2D; both low and high levels of plasma manganese were associated with higher odds of newly diagnosed T2D. The U-shaped association was not modified by the MnSOD rs4880 polymorphism.Citation:Shan Z, Chen S, Sun T, Luo C, Guo Y, Yu X, Yang W, Hu FB, Liu L. 2016. U-shaped association between plasma manganese levels and type 2 diabetes. Environ Health Perspect 124:1876–1881; http://dx.doi.org/10.1289/EHP176