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Boletus edulis mushroom behaved as an accumulating biosystem with respect to Ag, Rb, Zn, and K. The mushroom was not an efficient accumulator of toxic As, Pb, and Cr, but Se and Cd displayed much higher concentrations in the mushroom than in the substrate samples. Other elements were bioexclusive. Different elements had different within-mushroom mobilities. The highest mobilities were displayed by Zn and Ag, and the lowest by Ti. The mushroom’s fruiting body preferentially took up lighter Mg, Cu, and Cd isotopes (Δ26MgFB-soil = −0.75‰; Δ65CuFB-soil = −0.96‰; Δ114CdFB-soil = −0.63‰), and the heavier 66Zn isotope (Δ66ZnFB-soil = 0.92‰). Positive within-mushroom Zn isotope fractionation resulted in accumulation of the heavier 66Zn (Δ66Zncap-stipe = 0.12‰) in the mushroom’s upper parts. Cadmium displayed virtually no within-mushroom isotope fractionation. Different parts of the fruiting body fractionated Mg and Cu isotopes differently. The middle part of the stipe (3–6 cm) was strongly depleted in the heavier 26 Mg with respect to the 0–3 cm (Δ26Mgstipe(3–6)-stipe(0–3) = −0.73‰) and 6–9 cm (Δ26Mgstipe(6–9)-stipe(3–6) = 0.28‰) sections. The same stipe part was strongly enriched in the heavier 65Cu with respect to the 0–3 cm (Δ65Custipe(3–6)-stipe(0–3) = 0.63‰) and 6–9 cm (Δ65Custipe(6–9)-stipe(3–6) = −0.42‰) sections. An overall tendency for the upper mushroom’s parts to accumulate heavier isotopes was noted for Mg (Δ26Mgcap-stipe = 0.20‰), Zn (Δ66Zncap-stipe = 0.12‰), and Cd (Δ114Cdcap-stipe = 0.04‰), whereas Cu showed the opposite trend (Δ65Cucap-stipe = −0.08‰).

Two Neoproterozoic-Cambrian shale suites that consist of normal (NBS) and metal-rich (HMBS) black shales from the Tepla-Barrandian Unit, Bohemian Massif (Czech Republic) are studied in terms of their Cu, Zn, Cr and Re–Os isotopic compositions to improve our knowledge of elemental and isotopic mass balance of these elements in Earth's oceans in the past and the extent of surface oxygenation at the Neoproterozoic–Cambrian boundary. The rock compositions indicate that the inputs of Cu and Zn have been controlled by variable proportions of metal-rich authigenic and low-metal terrigenous sources, the latter having exceptionally low δ65Cu and partially δ66Zn. In this respect, our data confirm previous studies conclusions that organic-rich sediments with high a terrigenous flux play an important role in the sinking of light Zn in the oceans and provide new evidence that these types of rocks also represent the currently unidentified burial of very light Cu in the ocean. The chromium isotopic composition reveals a complex history of Cr uptake and fractionation through the dominant Cr input from different terrigenous sources with variable δ53Cr followed by Cr fractionation that was controlled by redox states (NBS). On the other hand, mixing and/or continuous equilibrium isotopic exchange between seawater and hydrothermal Cr was the dominant process for the HMBS. The Re–Os contents of the NBS were controlled by hydrogenous components, which yield a poorly defined Re–Os age for the least disturbed samples of 555 ± 60 Ma, indicating an open-system behavior, while the HMBS Re–Os composition was largely influenced by hydrothermal fluids during deposition. The calculated authigenic δ65Cu, which is similar to that in the present-day ocean, and highly positive δ53Cr values of the HMBS suggest high levels of surface oxygenation during the Neoproterozoic–Cambrian transition. Furthermore, the authigenic δ66Zn, which is indistinguishable from that in the present-day ocean, may imply a constant Zn isotopic composition of the oceans from the Neoproterozoic because of the well-balanced cycle of phosphates, which were strongly adsorbed by Fe-hydroxides. The radiogenic nature of the initial 187Os/188Os (~0.6), although with a high associated error, seems to not confirm previous indications of an abrupt increase of seawater 187Os/188Os during the late Neoproterozoic due to the large-scale radiogenic Os flux into the ocean.

Natural attenuation of groundwater contaminated by toxic hexavalent chromium [Cr(VI)] was studied at two industrial sites in the eastern U.S. Concentration and isotope composition of the residual Cr(VI) were determined at site A in Connecticut whose aquifer was polluted by electroplating solutions between 1930 and 1995, and at site B in New Jersey whose aquifer was polluted by soluble chromium-processing wastes between 1911 and 1963. Site A was characterized by lower mean Cr(VI) concentrations (2 mg L−1) and lower mean δ53CrCr(VI) values (1.84‰) in groundwater than site B (200 mg L−1 and 2.89‰, respectively). δ53CrCr(VI) values were strongly positively correlated with dissolved organic carbon (DOC; p = 0.002), but not with dissolved ferrous iron [Fe(II)], or divalent manganese [Mn(II)], indicating that DOC may have played a major role in spontaneous reduction of the mobile carcinogenic Cr(VI) to immobile non-toxic Cr(III). At site B, the supply of DOC may be nearly unlimited, due to the presence of a buried organic meadow mat at a depth of six meters below the ground surface. At site A, contaminated groundwater has been extracted and treated since 1995. The mean δ53CrCr(VI) values of the residual aqueous contamination at site A significantly decreased over the past 15 years (p

Headwater catchments underlain by ultramafic bedrock may release toxic amounts of hexavalent chromium [Cr(VI)] into runoff. Redox cycling of Cr during weathering, pedogenesis and runoff generation can be constrained by studying 53Cr/52Cr isotope systematics. We report a 12-month time-series of δ53Cr values of runoff from a small serpentinite-dominated catchment in Central Europe, complemented with a 5-year monitoring of Cr and DOC concentrations. δ53Cr values of bulk bedrock, rock-forming minerals, and bulk soil were also determined. Cr(VI) concentrations in runoff exceeded the 10-ppb maximum contaminant level by 70%. Concentrations of Cr(VI) in runoff were positively correlated with water discharge and DOC concentrations. Chromium export flux in winter was significantly higher than in summer. Runoff δ53Cr exhibited a temporal trend, with negative values (− 0.6‰) in winter and positive values (0.5‰) in summer. On an annual basis, the mass-weighted δ53Cr value of runoff was − 0.4‰. Dissolved Cr exported in winter was isotopically lighter than the within-site Cr sources: δ53Cr of bulk bedrock ranged from − 0.2 to 0.0‰, and δ53Cr of soil ranged from − 0.2 to 0.3‰. Chromium isotope analysis of seven rock-forming minerals separated from serpentinites, tremolite/actinolite schists and amphibolites revealed a much wider range of δ53Cr values, from − 0.4‰ (hornblende) to 1.7‰ (albite). Most of the variability in runoff δ53Cr can be explained by incongruent oxidative weathering, with a contribution of isotope-selective processes related to pedogenesis. Isotopically light Cr was preferentially mobilized from weathered bedrock and soil in cold, water-rich periods and exported via stream water. In these periods, precipitation water more rapidly penetrates into the soil than in summer months, characterized by lower rainfall and larger evapotranspiration, and more efficiently leaches the accumulated Cr(VI).

Chromium isotope systematics and concentrations of dissolved Cr were studied in shallow aquifers at four industrial sites in the Czech Republic, Central Europe. Chromium plating baths and wastewaters started to contaminate groundwater in the late 1940s. Since plating shops at all sites still operate, it was possible to determine the δ 53 Cr signatures of the plating baths. The mean δ 53 Cr values of the Cr plating baths, representing contamination sources, were 0.0‰ at Zlate Hory (ZH), 0.5‰ at Loucna nad Desnou (LD), 0.3‰ at Letnany (AV), and 0.1‰ at Velesin (JI). At all sites, groundwater Cr was isotopically heavier, compared to the contamination source, reflecting natural in-situ Cr(VI) reduction to insoluble Cr(III). The magnitude of the average positive isotope shift from the plating bath Cr(VI) to groundwater Cr aq , mostly residual Cr(VI), was 1.1‰, 1.3‰, 3.3‰ and 3.3‰ at ZH, LD, AV, and JI, respectively. The mean concentration of Cr aq was 0.43, 0.47, 2.38 and 4.32 mg L − 1 , respectively. AV and JI, the sites with lower residual Cr aq concentrations in groundwater, had higher δ 53 Cr values, suggesting higher rates/efficiency of Cr(VI) reduction, and of toxicity removal. Simple Rayleigh models indicated that as much as 60% of Cr(VI) has been removed from the groundwater by spontaneous reduction at AV and JI. At ZH and LD, the same models indicated a 30% Cr removal from the solution. Even if uncertainties in model application and Cr fractionation factors are considered, it appears that natural attenuation at Cr(VI)-polluted sites can improve groundwater quality by tens of percent in a relatively short period of time of several decades.

A number of shallow aquifers in industrial regions have been polluted by toxic Cr(VI). At some sites, spontaneous reduction of dissolved Cr(VI) to insoluble Cr(III) has been observed. Precipitation of non-toxic Cr(III) is accompanied by a Cr isotope fractionation, with the residual Cr(VI) becoming enriched in the heavier isotope 53 Cr, and depleted in the lighter isotope 52 Cr. Thus far, δ 53 Cr values of the contamination source have been poorly constrained. These values are needed to quantify the extent of Cr(VI) reduction in the aquifers. We present δ 53 Cr values of solutions generated during Cr-electroplating, chromating and anodizing at nine industrial sites. The source chemical, CrO 3 , had a mean δ 53 Cr of 0.0‰. A small-to-negligible Cr isotope fractionation was observed between the solutions of the plating baths and the source chemical. Across all sample types, the mean δ 53 Cr(VI) value was 0.2‰. The mean δ 53 Cr(VI) value of contaminated groundwater in the same region, studied previously, was significantly higher (2.9‰), indicating Cr(VI) reduction. Based on low δ 53 Cr(VI) values of plating baths and rinsewaters as potential contamination sources, and their low variability, we suggest that most aquifer δ 53 Cr(VI) values higher than 1.0‰ are a result of in-situ Cr(VI) reduction.

Our study represents ϵ(114/110) Cd NIST3108 values of materials resulting from anthropogenic activities such as coal burning, smelting, refining, metal coating, and the glass industry. Additionally, primary sources (ore samples, pigment, coal) processed in the industrial premises were studied. Two sphalerites, galena, coal and pigment samples exhibited ϵ(114/110) CdNIST3108 values of 1.0±0.2, 0.2±0.2, 1.3±0.1, -2.3±0.2 and -0.1±0.3, respectively. In general, all studied industrial processes were accompanied by Cd isotope fractionation. Most of the industrial materials studied were clearly distinguishable from the samples used as a primary source based on ϵ(114/110) Cd NIST3108 values. The heaviest ϵ(114/110) CdNIST3108 value of 58.6±0.9 was found for slag resulting from coal combustion, and the lightest ϵ(114/110) CdNIST3108 value of -23±2.5 was observed for waste material after Pb refinement. It is evident that ϵ(114/110) Cd NIST3108 values depend on technological processes, and in case of incomplete Cd transfer from source to final waste material, every industrial activity creates differences in Cd isotope composition. Our results show that Cd isotope analysis is a promising tool to track the origins of industrial waste products.

The alpha5beta1 integrin represent a new therapeutic target for glioblastoma, which are malignant brain tumors difficult to cure with conventional therapies. Glioblastoma are known to be highly resistant to chemotherapy. We, therefore, investigated whether blocking alpha5beta1 integrin with specific nonpeptidic antagonists concomitantly with chemotherapy (ellipticine and temozolomide) may impact the response to chemotherapy of human glioblastoma. Here we show that inhibiting alpha5beta1 integrin with 2 selective ligands (SJ749 and K34c) decreases chemotherapy-induced premature senescence and facilitates cell apoptosis in a functional p53 background (U87MG cells). When p53 is mutated and inactive (U373 cells), chemotherapy induces p53-independent cell apoptosis instead of senescence that is not improved by integrin antagonists. Silencing p53 in U87MG cells with siRNA as well as evaluating HCT116 p53+/+ and p53-/- colon carcinoma cell behavior support the hypothesis of an as yet unknown effect of alpha5beta1 integrin antagonists on the control of chemotherapy-induced premature senescence and apoptosis. alpha5beta1 integrin antagonists modulate the p53 signaling induced by chemotherapy. Our results highlight a new role of the alpha5beta1 integrin in the control of glioblastoma aggressiveness and responsiveness to chemotherapy, which may have a crucial impact in the clinical management of patients suffering from brain tumors.

Ellipticine is a potent antineoplastic agent exhibiting multiple mechanisms of action with promising brain tumor specificity. This anticancer agent should be considered a pro-drug, whose pharmacological efficiency and/or genotoxic side effects are dependent on its cytochrome P450 (CYP) - and/or peroxidase-mediated activation to species forming covalent DNA adducts. Ellipticine can also act as an inhibitor or inducer of biotransformation enzymes, thereby modulating its own metabolism leading to its genotoxic and pharmacological effects. The toxicity of ellipticine to U87MG glioblastoma cells and mechanisms of its action to these cells are aims of this study.Ellipticine metabolites formed in U87MG cells were analyzed using HPLC. Covalent DNA modifications by ellipticine were detected by 32P-postlabeling. CYP enzyme expression was examined by QPCR and Western blot.U87MG glioblastoma cell proliferation was efficiently inhibited by ellipticine. This effect might be associated with formation of two covalent ellipticine-derived DNA adducts, identical to those formed by 13-hydroxy- and 12-hydroxyellipticine, the ellipticine metabolites generated by CYP1A1, 1B1 and 3A4, lactoperoxidase and cyclooxygenase 1, the enzymes expressed in U87MG cells. Moreover, by inducing CYP1B1, 3A4 and 1A1 enzymes in U87MG cells, ellipticine increases its own enzymatic activation, thereby enhancing its own genotoxic and pharmacological potential in these cells. Ellipticine concentration used for U87MG cell treatment is extremely important for its pharmacological effects, as its metabolite profiles differed substantially predicting ellipticine to be either detoxified or activated.The results found in this study are the first report showing cytotoxicity and DNA adduct formation by ellipticine in glioblastomas.