Metal Ions Activate the Human Taste Receptor TAS2R7.

Divalent and trivalent salts exhibit a complex taste profile. They are perceived as being astringent/drying, sour, bitter, and metallic. We hypothesized that human bitter-taste receptors may mediate some taste attributes of these salts. Using a cell-based functional assay, we found that TAS2R7 responds to a broad range of divalent and trivalent salts, including zinc, calcium, magnesium, copper, manganese, and aluminum, but not to potassium, suggesting TAS2R7 may act as a metal cation receptor mediating bitterness of divalent and trivalent salts. Molecular modeling and mutagenesis analysis identified 2 residues, H943.37 and E2647.32, in TAS2R7 that appear to be responsible for the interaction of TAS2R7 with metallic ions. Taste receptors are found in both oral and extraoral tissues. The responsiveness of TAS2R7 to various mineral salts suggests it may act as a broad sensor, similar to the calcium-sensing receptor, for biologically relevant metal cations in both oral and extraoral tissues.

Tolerance Mechanisms to Copper and Zinc Excess in Rhizophora mucronata Lam. Seedlings Involve Cell Wall Sequestration and Limited Translocation.

Rhizophora mucronata is a common mangrove growing in habitats subjected to heavy metal (HM) contamination. Understanding their physiological responses to copper (Cu) and zinc (Zn) excess and underlying tolerance mechanisms is crucial to assess impacts of metal pollution on mangrove community. Seedlings were treated with Cu or Zn (0, 50 or 100 mg per plant) by means of a single addition. At day 3 and 7, Cu and Zn accumulation, photosynthetic efficiency, superoxide dismutase and peroxidase activity, non-protein thiols, reactive oxygen species and lipid peroxidation in roots and leaves were measured. R. mucronata restricted Cu and Zn translocation, thus accumulated HM mainly in roots while kept the leaves unaffected. However, high root HM did not induce oxidative stress nor anti-oxidative defense as HM were largely deposited in cell wall. We concluded that HM tolerance strategies of R. mucronata seedlings are exclusion and restriction of translocation to the vital photosynthetic tissue.

Selenium-binding protein 1: a sensitive urinary biomarker to detect heavy metal-induced nephrotoxicity.

Identifying novel biomarkers to detect nephrotoxicity is clinically important. Here, we attempted to identify new biomarkers for mercury-induced nephrotoxicity and compared their sensitivity to that of traditional biomarkers in animal models. Comparative proteomics analysis was performed in kidney tissues of Sprague-Dawley rats after oral treatment with HgCl2 (0.1, 1, or 5 mg/kg/day) for 21 days. Kidney cortex tissues were analyzed by two-dimensional gel electrophoresis/matrix-assisted laser desorption/ionization, and differentially expressed proteins were identified. The corresponding spots were quantitated by RT-PCR. Selenium-binding protein 1 (SBP1) was found to be the most markedly upregulated protein in the kidney cortex of rats after HgCl2 administration. However, blood urea nitrogen, serum creatinine, and glucose levels increased significantly only in the 1 or 5 mg/kg HgCl2-treated groups. A number of urinary excretion proteins, including kidney injury molecule-1, clusterin, monocyte chemoattractant protein-1, and ß-microglobulin, increased dose-dependently. Histopathological examination revealed severe proximal tubular damage in high-dose (5 mg/kg) HgCl2-exposed groups. In addition, urinary excretion of SBP1 significantly increased in a dose-dependent manner. To confirm the critical role of SBP1 as a biomarker for nephrotoxicity, normal kidney proximal tubular cells were treated with HgCl2, CdCl2, or cisplatin for 24 h. SBP1 levels significantly increased in conditioned media exposed to nephrotoxicants, but decreased in cell lysates. Our investigations suggest that SBP1 may play a critical role in the pathological processes underlying chemical-induced nephrotoxicity. Thus, urinary excretion of SBP1 might be a sensitive and specific biomarker to detect early stages of kidney injury.

Health risk assessment of potentially harmful elements and dietary minerals from vegetables irrigated with untreated wastewater, Pakistan.

In the developing world, vegetables are commonly grown in suburban areas irrigated with untreated wastewater containing potentially harmful elements (PHEs). In Pakistan, there is no published work on the bioaccessibility aspect of PHEs and dietary minerals (DMs) in sewage-irrigated soil or the vegetables grown on such soils in Pakistan. Several industrial districts of Pakistan were selected for assessment of the risk associated with the ingestion of vegetables grown over sewage-irrigated soils. Both the total and bioaccessible fraction of PHEs (Cd, Co, Cr, Ni, and Pb) and DMs (Fe, Cu, Mn, Zn, Ca, Mg, and I) in soils and vegetable samples were measured. The concentrations of these PHEs and DMs in sewage-irrigated and control soils were below published upper threshold limits. However, compared to control soils, sewage irrigation over the years decreased soil pH (7.7 vs 8.1) and enhanced dissolved organic carbon (1.8 vs 0.8 %), which could enhance the phyto-availability of PHEs and DMs to crops. Of the PHEs and DMs, the highest transfer factor (soil to plant) was noted for Cd and Ca, respectively. Concentrations of PHEs in most of the sewage-irrigated vegetables were below the published upper threshold limits, except for Cd in the fruiting portion of eggplant and bell pepper (0.06-0.08 mg/kg Cd, dry weight) at three locations in Gujarat and Kasur districts. The bioaccessible fraction of PHEs can reduce the context of dietary intake measurements compared to total concentrations, but differences between both measurements were not significant for Cd. Since the soils of the sampled districts are not overly contaminated compared to control sites, vegetables grown over sewage-irrigated soils would provide an opportunity to harvest mineral-rich vegetables potentially providing consumers 62, 60, 12, 104, and 63 % higher dietary intake of Cu, Mn, Zn, Ca, and Mg, respectively. Based on Fe and vanadium correlations in vegetables, it is inferred that a significant proportion of total dietary Fe intake could be contributed by soil particles adhered to the consumable portion of vegetables. Faecal sterol ratios were used to identify and distinguish the source of faecal contamination in soils from Gujranwala, Gujarat, and Lahore districts, confirming the presence of human-derived sewage biomarkers at different stages of environmental alteration. A strong correlation of some metals with soil organic matter concentration was observed, but none with sewage biomarkers.

Production of an antibiotic enterocin from a marine actinobacteria strain H1003 by metal-stress technique with enhanced enrichment using response surface methodology.

Elicitation by chemical means including heavy metals is one of a new technique for drug discoveries. In this research, the effect of heavy metals on marine actinobacteria Streptomyces sp. H-1003 for the production of enterocin, with a strong broad spectrum activity, along optimized fermented medium was firstly investigated. The optimum metal stress conditions consisted of culturing marine actinobacteria strain H-1003 with addition of cobalt ions at 2mM in optimized Gause's medium having starch at 20mg/L for 10 days at 180 revolution/min. Under these conditions, enterocin production was enhanced with a value of 5.33mg/L, which was totally absent at the normal culture of strain H-1003 and much higher than other tested metal-stress conditions. This work triumphantly announced a prodigious effect of heavy metals on marine actinobacteria with fringe benefits as a key tool of enterocin production.

Comparison of microbial taxonomic and functional shift pattern along contamination gradient.

BACKGROUND: The interaction mechanism between microbial communities and environment is a key issue in microbial ecology. Microbial communities usually change significantly under environmental stress, which has been studied both phylogenetically and functionally, however which method is more effective in assessing the relationship between microbial communities shift and environmental changes still remains controversial. RESULTS: By comparing the microbial taxonomic and functional shift pattern along heavy metal contamination gradient, we found that both sedimentary composition and function shifted significantly along contamination gradient. For example, the relative abundance of Geobacter and Fusibacter decreased along contamination gradient (from high to low), while Janthinobacterium and Arthrobacter increased their abundances. Most genes involved in heavy metal resistance (e.g., metc, aoxb and mer) showed higher intensity in sites with higher concentration of heavy metals. Comparing the two shift patterns, there were correlations between them, because functional and phylogenetic ß-diversities were significantly correlated, and many heavy metal resistance genes were derived from Geobacter, explaining their high abundance in heavily contaminated sites. However, there was a stronger link between functional composition and environmental drivers, while stochasticity played an important role in formation and succession of phylogenetic composition demonstrated by null model test. CONCLUSIONS: Overall our research suggested that the responses of functional traits depended more on environmental changes, while stochasticity played an important role in formation and succession of phylogenetic composition for microbial communities. So profiling microbial functional composition seems more appropriate to study the relationship between microbial communities and environment, as well as explore the adaptation and remediation mechanism of microbial communities to heavy metal contamination.

Effects of heavy metal exposure on the morphological and microscopical characteristics of the paddy plant.

The objective of the study was to determine the effects of heavy metal exposure on the morphology and anatomy of paddy plant (Oryza sativa L.). Paddy plants were treated with single and combined close of Cd and Pb (5, 10, 15, 20 and 25 ppm) at 35 days after germination. The results showed leaf chlorosis, decrease in number of roots and shoot height under both single and combined treatment. Heavy metal content in paddy was in the order of root>stem>grain>leaf and was highest at reproductive stage. A positive correlation was obtained between Cd, Pb and Cd-Pb concentrations in paddy plant parts with the concentrations of these metals in the soil. Scanning Electron Microscopic studies showed changes in the microscopic features due to accumulation of heavy metal and these included cell degeneration and thickening of cell walls, as well as increase in the number of treacherous elements in vascular cylinder and as residue in cells. Light microscope studies showed that Cd exposure caused dark deposits in the endodermal cells and vascular cylinder, as well as rupturing of parenchyma tissue. Results of the study indicated that paddy plants seemed to have some degree of tolerance to heavy metals.

Nanodiamonds act as Trojan horse for intracellular delivery of metal ions to trigger cytotoxicity.

BACKGROUND: Nanomaterials hold great promise for applications in the delivery of various molecules with poor cell penetration, yet its potential for delivery of metal ions is rarely considered. Particularly, there is limited insight about the cytotoxicity triggered by nanoparticle-ion interactions. Oxidative stress is one of the major toxicological mechanisms for nanomaterials, and we propose that it may also contribute to nanoparticle-ion complexes induced cytotoxicity. METHODS: To explore the potential of nanodiamonds (NDs) as vehicles for metal ion delivery, we used a broad range of experimental techniques that aimed at getting a comprehensive assessment of cell responses after exposure of NDs, metal ions, or ND-ion mixture: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Trypan blue exclusion text, optical microscope observation, synchrotron-based scanning transmission X-ray microscopy (STXM) and micro X-ray fluorescence (µXRF) microscopy, inductively coupled plasma-mass spectrometry (ICP-MS), reactive oxygen species (ROS) assay and transmission electron microscopy (TEM) observation. In addition, theoretical calculation and molecular dynamics (MD) computation were used to illustrate the adsorption properties of different metal ion on NDs as well as release profile of ion from ND-ion complexes at different pH values. RESULTS: The adsorption capacity of NDs for different metal ions was different, and the adsorption for Cu2+ was the most strong among divalent metal ions. These different ND-ion complexes then had different cytotoxicity by influencing the subsequent cellular responses. Detailed investigation of ND-Cu2+ interaction showed that the amount of released Cu2+ from ND-Cu2+ complexes at acidic lysosomal conditions was much higher than that at neutral conditions, leading to the elevation of intracellular ROS level, which triggered cytotoxicity. By theoretical approaches, we demonstrated that the functional carbon surface and cluster structures of NDs made them good vehicles for metal ions delivery. CONCLUSIONS: NDs played the Trojan horse role by allowing large amounts of metal ions accumulate into living cells followed by subsequent release of ions in the interior of cells, which then led to cytotoxicity. The present experimental and theoretical results provide useful insight into understanding of cytotoxicity triggered by nanoparticle-ion interactions, and open new ways in the interpretation of nanotoxicity.

Establishment of toxicity thresholds in subpopulations of coelomocytes (amoebocytes vs. eleocytes) of Eisenia fetida exposed in vitro to a variety of metals: implications for biomarker measurements.

Coelomocytes comprise the immune system of earthworms and due to their sensitivity responding to a wide range of pollutants have been widely used as target cells in soil ecotoxicology. Recently, in vitro assays with primary cultures of coelomocytes based in the neutral red uptake (NRU) assay have been developed as promising tools for toxicity assessment chemical in a reproducible and cost-effective manner. However, NRU showed a bimodal dose-response curve previously described after in vivo and in vitro exposure of earthworm coelomocytes to pollutants. This response could be related with alterations in the relative proportion of coelomocyte subpopulations, amoebocytes and eleocytes. Thus, the aims of the present work were, first, to establish the toxicity thresholds that could be governed by different cell-specific sensitivities of coelomocytes subpopulations against a series of metals (Cu, Cd, Pb, Ni), and second to understand the implication that coelomocyte population dynamics (eleocytes vs. amoebocytes) after exposure to pollutants can have on the viability of coelomocytes (measured by NRU assay) as biomarker of general stress in soil health assessment. Complementarily flow cytometric analyses were applied to obtain correlative information about single cells (amoebocytes and eleocytes) in terms of size and complexity, changes in their relative proportion and mortality rates. The results indicated a clear difference in sensitivity of eleocytes and amoebocytes against metal exposure, being eleocytes more sensitive. The bimodal dose-response curve of NRU after in vitro exposure of primary cultures of coelomocytes to metals revealed an initial mortality of eleocytes (decreased NRU), followed by an increased complexity of amoebocytes (enhanced phagocytosis) and massive mortality of eleocytes (increased NRU), to give raise to a massive mortality of amoebocytes (decrease NRU). A synergistic effect on NRU was exerted by the exposure to high Cu concentrations and acidic pH (elicited by the metal itself), whereas the effects on NRU produced after exposure to Cd, Ni and Pb were due solely to the presence of metals, being the acidification of culture medium meaningless.

In-feed use of heavy metal micronutrients in U.S. swine production systems and its role in persistence of multidrug-resistant salmonellae.

The study aimed to characterize the role of heavy metal micronutrients in swine feed in emergence of heavy-metal-tolerant and multidrug-resistant Salmonella organisms. We conducted a longitudinal study in 36 swine barns over a 2-year period. The feed and fecal levels of Cu(2+) and Zn(2+) were measured. Salmonella was isolated at early and late finishing. MICs of copper sulfate and zinc chloride were measured using agar dilution. Antimicrobial susceptibility was tested using the Kirby-Bauer method, and 283 isolates were serotyped. We amplified pcoA and czcD genes that encode Cu(2+) and Zn(2+) tolerance, respectively. Of the 283 isolates, 113 (48%) showed Cu(2+) tolerance at 24 mM and 164 (58%) showed Zn(2+) tolerance at 8 mM. In multivariate analysis, serotype and source of isolates were significantly associated with Cu(2+) tolerance (P < 0.001). Fecal isolates were more likely to be Cu(2+) tolerant than those of feed origin (odds ratio [OR], 27.0; 95% confidence interval [CI], 2.8 to 250; P = 0.0042) or environmental origin (OR, 5.8), implying the significance of gastrointestinal selective pressure. Salmonella enterica serotypes Typhimurium and Heidelberg, highly significant for public health, had higher odds of having >20 mM MICs of Cu(2+) than did "other" serotypes. More than 60% of Salmonella isolates with resistance type (R-type) AmStTeKm (32 of 53) carried pcoA; only 5% with R-type AmClStSuTe carried this gene. czcD gene carriage was significantly associated with a higher Zn(2+) MIC (P < 0.05). The odds of having a high Zn(2+) MIC (≥8 mM) were 14.66 times higher in isolates with R-type AmClStSuTe than in those with R-type AmStTeKm (P < 0.05). The findings demonstrate strong association between heavy metal tolerance and antimicrobial resistance, particularly among Salmonella serotypes important in public health.

Association of recent exposure to ambient metals on fractional exhaled nitric oxide in 9-11 year old inner-city children.

Exposure to ambient metals in urban environments has been associated with wheeze, and emergency room visits and hospitalizations due to respiratory illness. However, the effect of ambient metals exposure on airway inflammation, and how these associations may be modified by seroatopy, has not been determined. Fractional exhaled nitric oxide (FENO) is a reliable proxy marker of airway inflammation. We hypothesized that recent ambient concentrations of Ni, V, Zn and Fe would be associated differentially with proximal and distal fractions of exhaled NO, and that these associations would be modified by seroatopy. As part of the Columbia Center for Children's Environmental Health (CCCEH) birth cohort study, 9-11 year old children (n=192) were evaluated. Ambient measures of Ni, V, Zn and Fe were obtained from a local central monitoring site and averaged over 9 days based on three 24h measures every third day. Fractional exhaled nitric oxide (FENO) samples were obtained at constant flows of 50 (FENO50), 83 and 100mL/s, and used to determine surrogate measures for proximal (JNO) and alveolar (Calv) inflammation. Seroatopy was determined by specific IgE at age 7. Data were analyzed using multivariable linear regression. Ambient V and Fe concentrations were associated positively with FENO50 (p=0.018, p=0.027). Ambient Fe was associated positively with JNO (p=0.017). Ambient Ni and V concentrations were associated positively with Calv (p=0.004, p=0.018, respectively). A stronger association of Ni concentrations with Calv was observed among the children with seroatopy. These results suggest that ambient metals are associated differentially with different fractions of FENO production, and this relationship may be modified by seroatopy.

Oxidative stress biomarkers in Eurasian eagle owls (Bubo bubo) in three different scenarios of heavy metal exposure.

The main aim of the present study is the assessment of oxidative stress related to metals in the Eurasian eagle owl (Bubo bubo) from three areas (agricultural and rural area, industrial area, and mining area) of Murcia, Southern Spain. Mean blood metal concentrations were Cd=0.07±0.21, Pb=3.27±5.21, Cu=10.62±4.77, Zn=311.47±67.14, Hg=2.32±3.83 µg/dl wet weight. Although individuals from the mining area had significant higher Pb and Hg concentrations, and significant lower glutathione-S-transferase (GST) and catalase (CAT) activities in red blood cells (RBC); the lack of differences in oxidative damage to membrane lipids (TBARS) among areas suggests that the antioxidant capacity of the different populations is able to deal with oxidant species and maintain TBARS levels in the same amount. Despite the low levels of metals, several oxidative stress biomarkers were correlated with metal concentrations. This study provides threshold concentrations at which metals cause effects on the antioxidant system in Eagle owls. Blood Cd concentrations greater than 0.3 µg/dl produced an inhibition in GPx (32%) and CAT (26%) activity in RBC. However, Cd concentrations higher than 0.02 µg/dl were enough to produce an inhibition of these enzymes. Regarding Pb levels, blood concentrations above 2 µg/dl produced an inhibition of 8% and 10.5% in GPx and CAT activities, respectively, in RBC. A depletion of 16% and 4% in tGSH levels was associated with Pb concentrations higher than 15 and 3 µg/dl, respectively, in individuals from the ancient mine site. In addition, Pb concentrations above 2 and 10 µg/dl produced a TBARS induction of 10% and 28%, respectively, in individuals from both the industrial and the mining area. Finally, Hg concentrations greater than 3 and 10 µg/dl resulted in a TBARS induction of 102% and 190%, respectively, in Eurasian eagle owls from the industrial area. Our findings show that Pb may produce effects on oxidative stress biomarkers in Strigiformes at lower concentrations than those typically accepted for considering physiological effects in Falconiformes (20 µg/dl in blood). In addition, we provide new data on Hg and Cd concentrations related to effects in the antioxidant system.

Oral bioaccessibility of toxic metals in contaminated oysters and relationships with metal internal sequestration.

The Hong Kong oysters Crassostrea hongkongensis are widely farmed in the estuarine waters of Southern China, but they accumulate Cu and Zn to alarmingly high concentrations in the soft tissues. Health risks of seafood consumption are related to contaminants such as toxic metals which are bioaccessible to humans. In the present study, we investigated the oral bioaccessibility of five toxic metals (Ag, Pb, Cd, Cu and Zn) in contaminated oysters collected from different locations of a large estuary in southern China. In all oysters, total Zn concentration was the highest whereas total Pb concentration was the lowest. Among the five metals, Ag had the lowest oral bioaccessibility (38.9-60.8%), whereas Cu and Zn had the highest bioaccessibility (72.3-93.1%). Significant negative correlation was observed between metal bioaccessibility and metal concentration in the oysters for Ag, Cd, and Cu. We found that the oral bioaccessibility of the five metals was positively correlated with their trophically available metal fraction (TAM) in the oyster tissues, and negatively correlated with metal distribution in the cellular debris. Thus, metal partitioning in the TAM and cellular debris controlled the oral bioaccessibility to humans. Given the dependence of oral bioaccessibility on tissue metal contamination, bioaccessibility needs to be incorporated in the risk assessments of contaminated shellfish.

Comparative study of hematological responses to platinum group metals, antimony and silver nanoparticles in animal models.

Research was conducted to examine the hematological effects of heavy metals (platinum (Pt ((IV))), palladium (Pd ((II))), rhodium (Rh ((III))), antimony (Sb ((III)) and Sb ((V))), and silver nanoparticles (AgNPs)) on white blood cells in mammalian (rat) and avian (chick embryo) models. These metals are used in many everyday products and are accumulating in our environment. Six-week old Sprague-Dawley female rats were treated daily by gavage and six-day old, fertile, specific pathogen-free white leghorn strain chick embryos' eggs were injected on days 7 and 14 of incubation with 0.0, 1.0, 5.0 or 10.0 ppm concentrations of Pt ((IV)) and a platinum group metal (PGM) mix of Pt ((IV)), Pd ((II)) and Rh ((III)). Chick embryos were also tested with 1.0 or 5.0 ppm of antimony compounds (Sb ((III)) and Sb ((V))) and 0.0, 15.0, 30.0, 60.0, or 100.0 ppm of silver nanoparticles (AgNPs). After 8 weeks of treatment, blood was obtained from the rats by jugular cut down and from chick embryos on day 20 of incubation by heart puncture. Blood smears were made and stained and a differential white cell count was performed on each. Examination of the smears revealed unconventional dose responses, stimulation of the immune response, and decreases in leukocyte production with various metals and concentrations. Chick embryos responded differently than rats to Pt and the PGM mix; suggesting that species differences and/or stage of development are important components of response to heavy metals. Route of administration of the metals might also influence the response. All of the heavy metals tested affected the immune responses of the tested animals as demonstrated by changes in the types and numbers of leukocytes. Our findings warrant further research to determine the mechanism of these effects and to understand and prevent toxicological effects in humans and other living organisms.

From tolerance to acute metabolic deregulation: contribution of proteomics to dig into the molecular response of alder species under a polymetallic exposure.

Alnus spp. are actinorhizal trees commonly found in wet habitats and able to grow effectively in soil slightly contaminated with metal trace- elements. Two clones belonging to two Alnus species, namely, A. incana and A. glutinosa, were grown in hydroponics and exposed for 9 weeks to a Cd + Ni + Zn polymetallic constraint. Although responding by a similar decrease in total biomass production, the proteomic analysis associated with the study of various biochemical parameters including carbohydrate and mineral analyses revealed that the two clones have a distinct stress-responsive behavior. All parameters indicated that the roots, the organ in direct contact with the media, are more affected than the leaves. In fact, in A. glutinosa the response was almost completely confined to the roots, whereas many proteins change significantly in the roots and in the leaves of the treated A. incana. In both clones, the changes affected a broad range of metabolic processes such as redox regulation and energy metabolism and induced the production of pathogenesis-related proteins. In particular, changes in the accumulation of bacterial proteins that were not identified as coming from the known symbionts of Alnus were reported. Further investigation should be performed to identify their origin and exact role in the plant response to the polymetallic exposure tested here.

Chronic ingestion of cadmium and lead alters the bioavailability of essential and heavy metals, gene expression pathways and genotoxicity in mouse intestine.

Chronic ingestion of environmental heavy metals such as lead (Pb) and cadmium (Cd) causes various well-documented pathologies in specific target organs following their intestinal absorption and subsequent accumulation. However, little is known about the direct impact of the non-absorbed heavy metals on the small intestine and the colon homeostasis. The aim of our study was to compare the specific bioaccumulation and retention of Cd and Pb and their effect on the essential metal balance in primary organs, with those occurring specifically in the gastrointestinal tract of mice. Various doses of Cd (5, 20 and 100 mg l(-1)) and Pb (100 and 500 mg l(-1)) chloride salts were provided in drinking water for subchronic to chronic exposures (4, 8 and 12 weeks). In contrast to a clear dose- and time-dependent accumulation in target organs, results showed that intestines are poor accumulators for Cd and Pb. Notwithstanding, changes in gene expression of representative intestinal markers revealed that the transport-, oxidative- and inflammatory status of the gut epithelium of the duodenum, ileum and colon were specifically affected by both heavy metal species. Additionally, in vivo comet assay used to evaluate the impact of heavy metals on DNA damage showed clear genotoxic activities of Cd, on both the upper and distal parts of the gastrointestinal tract. Altogether, these results outline the resilience of the gut which balances the various effects of chronic Cd and Pb in the intestinal mucosa. Collectively, it provides useful information for the risk assessment of heavy metals in gut homeostasis and further disease's susceptibility.

Toxic effects of the ingestion of water-soluble elements found in soil under the atmospheric influence of an industrial complex.

In this study, we investigated the toxic effects of water-soluble elements from a contaminated soil via gavage in a single dose, simulating a geophagy event. The contaminated soil was collected in a field located in an industrial complex, and the control soil was collected in a reference area. Metabolic and behavioral parameters in Wistar male rats were measured after 24 and 96 h of gavage. After 96 h, the major organs were weighed, blood was collected to check hematological parameters, the bone marrow was taken for the micronucleus test, and the liver was used for evaluating the total antioxidant capacity, lipoperoxidation and protein carbonylation. Animals exposed to contaminated soil presented a few significant alterations by comparison with control animals: TBARS and protein carbonyl levels increased, the relative weight of the kidneys increased, metabolic parameters (body weight gain, food intake, water consumption, urine and feces production) depressed and there was behavioral alteration. These findings suggest that soils impacted by atmospheric contaminants can affect the organism physiological status jeopardizing the health of populations living in industrial areas. Finally, this study reassures that ingestion of potentially contaminated soils, even for short periods of time, can cause health risks.

Assessment of essential and nonessential metals and different metal exposure biomarkers in the human placenta in a population from the south of Portugal.

The general population is exposed to metals as trace amounts of metallic compounds are present in air, water, and food. Information on background exposures and biomarker concentrations of environmental chemicals in the general Portuguese population is limited. Therefore, the purpose of this study was to determine the levels of important nonessential metals with recognized toxicity cadmium (Cd) and lead (Pb) and essential metals copper (Cu), nickel (Ni), chromium (Cr), and zinc (Zn) in placentas of mothers living in south Portugal (Algarve). Due to the difficulty in establishing the effects of chemicals in a complex and variable environment, this study also aimed to examine the response of biomarkers, such as biochemical changes that occurs at subcellular levels in the presence of contaminants. The investigated biomarkers in placentas indicative of metal exposure or damage included the metallothioneins (MT), delta-aminolevulinic acid dehydratase (ALAD) (specific for Pb), and lipid peroxidation (LPO) as an index of oxidative stress damage. Moreover, HJ-BIPLOT was applied in order to identify and categorize mothers vulnerable to environmental contamination in this region. Metal concentrations in the placenta were not excessive but within the range found in most European studies. In general, the biomarkers MT and LPO were positively correlated with metal levels, while with ALAD the opposite occurred, indicating the selected battery of biomarkers were suitable to study the effects of metals on human placenta. Further, the application of multivariate analysis with HJ-BIPLOT showed that most significant factors contributing to maternal and fetal exposures via placenta were dietary and smoking habits.

Metal(loid) levels in biological matrices from human populations exposed to mining contamination--Panasqueira Mine (Portugal).

Mining activities may affect the health of miners and communities living near mining sites, and these health effects may persist even when the mine is abandoned. During mining processes various toxic wastes are produced and released into the surrounding environment, resulting in contamination of air, drinking water, rivers, plants, and soils. In a geochemical sampling campaign undertaken in the Panasqueira Mine area of central Portugal, an anomalous distribution of several metals and arsenic (As) was identified in various environmental media. Several potentially harmful elements, including As, cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se), were quantified in blood, urine, hair, and nails (toe and finger) from a group of individuals living near the Panasqueira Mine who were environmentally and occupationally exposed. A group with similar demographic characteristics without known exposure to mining activities was also compared. Genotoxicity was evaluated by means of T-cell receptor (TCR) mutation assay, and percentages of different lymphocyte subsets were selected as immunotoxicity biomarkers. Inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis showed elevated levels of As, Cd, Cr, Mn, and Pb in all biological samples taken from populations living close to the mine compared to controls. Genotoxic and immunotoxic differences were also observed. The results provide evidence of an elevated potential risk to the health of populations, with environmental and occupational exposures resulting from mining activities. Further, the results emphasize the need to implement preventive measures, remediation, and rehabilitation plans for the region.

Immune responses in lactating Holstein cows supplemented with Cu, Mn, and Zn as sulfates or methionine hydroxy analogue chelates.

The aim of this study was to compare effects of inorganic sulfate versus chelated forms of supplemental Cu, Mn, and Zn on milk production, plasma and milk mineral concentrations, neutrophil activity, and antibody titer response to a model vaccination. Holstein cows (n=25) were assigned in 2 cohorts based on calving date to a 12-wk randomized complete block design study. The first cohort consisted of 17 cows that had greater days in milk (DIM; mean of 77 DIM at the start of the trial) than the second cohort of 8 cows (32 DIM at the start of the trial). Diets were formulated to supplement 100% of National Research Council requirements of Cu, Mn, and Zn by either inorganic trace minerals (ITM) in sulfate forms or chelated trace minerals (CTM) supplied as metal methionine hydroxy analog chelates, without accounting for trace mineral contribution from other dietary ingredients. Intake and milk production were recorded daily. Milk composition was measured weekly, and milk Cu, Mn, and Zn were determined at wk 0 and 8. Plasma Cu and Zn concentrations and neutrophil activity were measured at wk 0, 4, 8, and 12. Neutrophil activity was measured by in vitro assays of chemotaxis, phagocytosis, and reactive oxygen species production. A rabies vaccination was administered at wk 8, and vaccine titer response at wk 12 was measured by both rapid fluorescent focus inhibition test and ELISA. Analyzed dietary Cu was 21 and 23mg/kg, Mn was 42 and 46mg/kg, and Zn was 73 and 94mg/kg for the ITM and CTM diets, respectively. No effect of treatment was observed on milk production, milk composition, or plasma minerals. Dry matter intake was reduced for CTM compared with ITM cows, but this was largely explained by differences in body weight between treatments. Milk Cu concentration was greater for CTM than ITM cows, but this effect was limited to the earlier DIM cohort of cows and was most pronounced for multiparous compared with primiparous cows. Measures of neutrophil function were unaffected by treatment except for an enhancement in neutrophil phagocytosis with the CTM treatment found for the later DIM cohort of cows only. Rabies antibody titer in CTM cows was 2.8 fold that of ITM cows as measured by ELISA, with a trend for the rapid fluorescent focus inhibition test. Supplementation of Cu, Mn, and Zn as chelated sources may enhance immune response of early lactation dairy cows compared with cows supplemented with inorganic sources.