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  • Iron–oxide minerals in the human tissues
    Biometals (IF 2.455) Pub Date : 2020-01-22
    H. Svobodova, D. Kosnáč, H. Tanila, A. Wagner, M. Trnka, P. Vitovič, J. Hlinkova, E. Vavrinsky, H. Ehrlich, Š. Polák, M. Kopani

    Abstract Iron is critically important and highly regulated trace metal in the human body. However, in its free ion form, it is known to be cytotoxic; therefore, it is bound to iron storing protein, ferritin. Ferritin is a key regulator of body iron homeostasis able to form various types of minerals depending on the tissue environment. Each mineral, e.g. magnetite, maghemite, goethite, akaganeite or hematite, present in the ferritin core carry different characteristics possibly affecting cells in the tissue. In specific cases, it can lead to disease development. Widely studied connection with neurodegenerative conditions is widely studied, including Alzheimer disease. Although the exact ferritin structure and its distribution throughout a human body are still not fully known, many studies have attempted to elucidate the mechanisms involved in its regulation and pathogenesis. In this review, we try to summarize the iron uptake into the body. Next, we discuss the known occurrence of ferritin in human tissues. Lastly, we also examine the formation of iron oxides and their involvement in brain functions.

    更新日期:2020-01-23
  • Zinc gluconate supplementation impacts the clinical improvement in patients with ulcerative colitis
    Biometals (IF 2.455) Pub Date : 2020-01-19
    Mayara Storel Beserra de Moura, Nina Rosa Mello Soares, Susy Érika de Lima Barros, Flaviane Alves de Pinho, Tomas Magno Costa Silva, Débora Cavalcante Bráz, Edivan Carvalho Vieira, Murilo Moura Lima, José Miguel Luz Parente, Dilina do Nascimento Marreiro, Adalberto Socorro da Silva, Nadir do Nascimento Nogueira

    Abstract Ulcerative colitis is an inflammatory bowel disease that affects the mucous membrane of the colon. The pathogenesis is not clear, but there is evidence of a complex interaction between genetic, environmental, and immunological factors. In this regard, we highlight the role of zinc in the immune system and probable control of the disease. This study evaluated the effect of zinc supplementation on the inflammatory response in patients with ulcerative colitis. A blind interventional study involving 41 patients of both sexes, who underwent either zinc gluconate supplementation (n = 23), or treatment with a placebo (corn starch) (n = 18). Patients were evaluated for dietary zinc intake, plasma and erythrocyte zinc concentrations, and serum levels of Th1/Th2/Th17 type cytokines at baseline (T0) and 30 (T1) and 60 (T2) days after intervention. Patients in the zinc supplementation group had a lower probability of having an adequate zinc intake than placebo. In this same group, there was a significant difference between plasma zinc concentrations (T1 in relation to T0, T2 in relation to T1, and T2 in relation to T0) and erythrocyte zinc (T1 in relation to T0 and T2 in relation to T1). Zinc supplementation resulted in significant changes in the concentrations of IL-2 and IL-10 without differences in the other interleukins. Zinc gluconate intervention in patients with ulcerative colitis improves the nutritional status of this mineral in these patients and positively influences their clinical outcome, reinforcing the role of zinc as an important dietary component in disease control.

    更新日期:2020-01-21
  • Estimation and in-situ detection of thorium in human liver cell culture by arsenazo-III based colorimetric assay
    Biometals (IF 2.455) Pub Date : 2020-01-02
    Rakhee Yadav, Badri N. Pandey, Amit Kumar

    Abstract To understand the biological effects of Thorium-232 (Th) in human cells and animal models as well as to assess mitigation strategies for its detoxification, there is a need to develop a sensitive, specific, high-throughput and easily-implementable assay for detection and estimation of Th in biological samples. Here, we have optimized arsenazo-III dye based colorimetric assay to detect Th in biological samples. The concentration of arsenazo-III (i.e. 50 µM) was optimized, which can reliably estimate Th in the concentration range of 2.5 to 40 µM. The optimized assay can specifically detect Th without interference from other metal ions (La, Ce, U, Fe, Ca, Cu, Zn and Mn). A significant correlation (R2 = 0.999) was found between arsenazo-III-based detection of Th and total reflection X-ray fluorescence. The conditions of present assay successfully estimated Th in cell culture medium, cell harvesting (trypsin-EDTA) solution and cell lysate obtained from human liver cell culture. Moreover, for the first time, we detected Th in-situ in adherent liver cells in culture after staining with arsenazo-III. This study confirms that Th can be specifically determined in biological samples using arsenazo-III with the sensitivity, which is relevant to thorium toxicity research. Graphic abstract

    更新日期:2020-01-04
  • Quantitative proteomic analysis reveals that the Rap1/MAPK/ERK pathway is inhibited through selenomethionine strengthening antioxidant activity
    Biometals (IF 2.455) Pub Date : 2019-12-13
    Zhe Liu, Feng Zhang, Lina Cui, Jihong Wang, Ping Lu, Rui Zhao, Hua Zhang, Jianfa Wang, Chunqiu Li, Rui Wu

    To investigate the influence on the proteome of chicken skeletal muscles of Selenomethionine (SeMet) use, 36 chicks were fed with SeMet feeding for 35 days. A total of 72 1-day old broiler chicks were randomly allocated into two groups (n = 36/group): the control group (C group), the SeMet supplemented group (SeMet group). The Selenium (Se) concentrations of skeletal muscles from the chicks with basal diet (negative control group) and SeMet feeding were found to be 0.01 mg/kg and 0.40 mg/kg, respectively. The skeletal muscles from the two groups were investigated using isobaric Tags for Relative and Absolute Quantitation (iTRAQ), coupled with liquid chromatography-tandem mass spectrometry (LC–MS/MS) analysis. This proteomic analysis identified proteins that were differentially expressed between the two groups. A total of 3564 proteins from the SeMet and the control (C) groups at 35 days were analyzed. 86 proteins were found by iTRAQ to be differentially expressed in the SeMet group, including 38 up-regulated proteins and 48 down-regulated proteins. These differential proteins were later identified as being mainly involved in antioxidant and enzyme-regulating activities. Fluorescent quantitative PCR(qPCR) and Western blot analyse proved to be consistent with the results of iTRAQ identification. The differentially expressed proteins (DEPs) identified in our work could be specific biomarkers related to SeMet intake in chicks. SeMet intake may strengthen antioxidant activity through Rap1/mitogen-activated protein kinases (MAPK)/extracellular signal-regulated kinase (ERK) signal pathways.

    更新日期:2019-12-13
  • Investigation of total zinc contents and zinc-protein profile in medicinal plants traditionally used for diabetes treatment
    Biometals (IF 2.455) Pub Date : 2019-12-06
    Ammar M. Ebrahim, Ahmed O. Alnajjar, Maged E. Mohammed, Abubakr M. Idris, Mohammed E. A. Mohammed, Bernhard Michalke

    This study aims at the assessment of total zinc contents, water zinc extract contents and zinc-protein profile in medicinal plants traditionally used for diabetes treatment. While zinc-protein profile was screened in plant samples using the online coupling of size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC–ICP–MS), total zinc contents and zinc water extract contents were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). The analysis of two certified reference materials with similar matrix for total zinc content revealed recovery values of 97.1% and 100.5% while the average of recovery of the summed Zn concentrations from protein fractions compared to total Zn was 103.0 ± 4.8%. Based on the FAO/WHO classification, Sesamum indicum, Nigella sativa, Trigonella Foenum-graecum and Pennisetum glaucum are classified as highest Zn-content. For protein profile, zinc was quantified in 330–430 and 50–60 kDa fractions of all examined plants while no contents were quantified in the inorganic fraction 0.05–0.4 kDa of all plant species. Also, only three plant species recorded Zn contents in the phytate fraction (0.9–1.5 kDa fraction). The fruits of the Momordica Charantia and the Citrullus colocynthis were with the highest extractable zinc concentration; 13.55 ± 0.45 and 10.08 ± 0.63 mg/kg, respectively. The highest Zinc capturing capacity was reported for the 50–60 and 70–87 KDa protein fractions.

    更新日期:2019-12-06
  • Investigation of PIC1 (permease in chloroplasts 1) gene’s role in iron homeostasis: bioinformatics and expression analyses in tomato and sorghum
    Biometals (IF 2.455) Pub Date : 2019-12-04
    Ertugrul Filiz, M. Aydın Akbudak

    Iron (Fe) is a crucial micronutrient in plant metabolism; thus, iron homeostasis is critical for plant development. Permease in chloroplast 1 (PIC1) is the first protein determined in the chloroplast playing a role iron homeostasis. In the present study, the PIC1 gene was investigated at a genome-wide scale in four plant genomes; Arabidopsis, tomato, maize and sorghum. Based on the gene ontology database, 21 GO terms were found related to the PIC1 gene, most of which were involved in iron hemostasis and transport. The digital expression data revealed that the expression of the majority of PIC1 genes (62.5%) in Arabidopsis decreased under abiotic stress conditions. Expression profiles of tomato PIC1 (SlPIC1) and sorghum PIC1 (SbPIC1) genes were also analyzed under salt and drought stress conditions using Real Time-quantitative PCR (RT-qPCR). Our wet-lab studies demonstrated that the SbPIC1 gene was down-regulated under salt and drought stresses in all tissues, while SlPIC1 was up-regulated in all but root tissue under drought stress. Some structural variations were detected in predicted 3D structures of PIC1 proteins and the structural similarity values varied between 0.23 and 0.35. Consequently, these results may contribute to the understanding of the PIC1 gene in iron transport and homeostasis in plants.

    更新日期:2019-12-04
  • Using FluoZin-3 and fura-2 to monitor acute accumulation of free intracellular Cd 2+ in a pancreatic beta cell line
    Biometals (IF 2.455) Pub Date : 2019-11-21
    Latha M. Malaiyandi, Harsh Sharthiya, Ameir N. Barakat, Joshua R. Edwards, Kirk E. Dineley

    The understanding of cellular Cd2+ accumulation and toxicity is hampered by a lack of fluorescent indicators selective for intracellular free Cd2+ ([Cd2+]i). In this study, we used depolarized MIN6 mouse pancreatic beta cells as a model for evaluating [Cd2+]i detection with commercially available fluorescent probes, most of which have been traditionally used to visualize [Ca2+]i and [Zn2+]i. We trialed a panel of 12 probes including fura-2, FluoZin-3, Leadmium Green, Rhod-5N, indo-1, Fluo-5N, and others. We found that the [Zn2+]i probe FluoZin-3 and the traditional [Ca2+]i probe fura-2 responded most consistently and robustly to [Cd2+]i accumulation mediated by voltage-gated calcium channels. While selective detection of [Cd2+]i by fura-2 required the omission of Ca2+ from extracellular buffers, FluoZin-3 responded to [Cd2+]i similarly in the presence or absence of extracellular Ca2+. Furthermore, we showed that FluoZin-3 and fura-2 can be used together for simultaneous monitoring of [Ca2+]i and [Cd2+]i in the same cells. None of the other fluorophores tested were effective [Cd2+]i detectors in this model.

    更新日期:2019-11-21
  • Correction to: Structural and solution chemistry, antiproliferative effects, and serum albumin binding of three pseudohalide derivatives of auranofin
    Biometals (IF 2.455) Pub Date : 2019-11-19
    Damiano Cirri, Maria Giulia Fabbrini, Lara Massai, Serena Pillozzi, Annalisa Guerri, Alessio Menconi, Luigi Messori, Tiziano Marzo, Alessandro Pratesi

    In the initial online publication, the given name of the first author was incorrectly displayed and should have read Damiano. The original article has been corrected and the proper representation of the authors’ names and their affiliation is also listed here.

    更新日期:2019-11-19
  • Structural and solution chemistry, antiproliferative effects, and serum albumin binding of three pseudohalide derivatives of auranofin
    Biometals (IF 2.455) Pub Date : 2019-11-04
    Damino Cirri, Maria Giulia Fabbrini, Lara Massai, Serena Pillozzi, Annalisa Guerri, Alessio Menconi, Luigi Messori, Tiziano Marzo, Alessandro Pratesi

    Three pseudohalide analogues of the established gold drug auranofin (AF hereafter), of general formula Au(PEt3)X, i.e. Au(PEt3)CN, Au(PEt3)SCN and Au(PEt3)N3 (respectively denoted as AFCN, AFSCN and AFN3), were prepared and characterized. The crystal structure was solved for Au(PEt3)SCN highlighting the classical linear geometry of the 2-coordinate gold(I) center. The solution behaviour of the compounds was then comparatively analysed through 31PNMR providing evidence for an acceptable stability under physiological-like conditions. Afterward, the reaction of these gold compounds with bovine serum albumin (BSA) and consequent adduct formation was investigated by 31PNMR. For all the studied gold compounds, the [Au(PEt3)]+ moiety was identified as the reactive species in metal/protein adducts formation. The cytotoxic effects of the complexes were subsequently measured in comparison to AF against a representative colorectal cancer cell line and found to be still relevant and roughly similar in the three cases though far weaker than those of AF. These results show that the nature of the anionic ligand can modulate importantly the pharmacological action of the gold-triethylphosphine moiety, affecting the cytotoxic potency. These aspects may be further explored to improve the pharmacological profiles of this family of metal complexes.

    更新日期:2019-11-04
  • Characterization of the copper-sensing transcriptional regulator CopR from the hyperthermophilic archeaon Thermococcus onnurineus NA1
    Biometals (IF 2.455) Pub Date : 2019-11-01
    Seo-Yeon Kim, Hong Joo Jeong, Minwook Kim, Ae Ran Choi, Min-Sik Kim, Sung Gyun Kang, Sung-Jae Lee

    A putative copper ion-sensing transcriptional regulator CopR (TON_0836) from Thermococcus onnurineus NA1 was characterized. The CopR protein consists of a winged helix-turn-helix DNA-binding domain in the amino-terminal region and a TRASH domain that is assumed to be involved in metal ion-sensing in the carboxyl-terminal region. The CopR protein was most strongly bound to a region between its own gene promoter and a counter directional promoter region for copper efflux system CopA. When the divalent metals such as nickel, cobalt, copper, and iron were present, the CopR protein was dissociated from the target promoters on electrophoretic mobility shift assay (EMSA). The highest sensible ion is copper which affected protein releasing under 10 µM concentrations. CopR recognizes a significant upstream region of TATA box on CopR own promoter and acts as a transcriptional repressor in an in vitro transcription assay. Through site-directed mutagenesis of the DNA-binding domain, R34M mutant protein completely lost the DNA-binding activity on target promoter. When the conserved cysteine residues in C144XXC147 motif 1 of the TRASH domain were mutated into glycine, the double cysteine residue mutant protein alone lost the copper-binding activity. Therefore, CopR is a copper-sensing transcriptional regulator and acts as a repressor for autoregulation and for a putative copper efflux system CopA of T. onnurineus NA1.

    更新日期:2019-11-04
  • DIBI, a novel 3-hydroxypyridin-4-one chelator iron-binding polymer, inhibits breast cancer cell growth and functions as a chemosensitizer by promoting S-phase DNA damage
    Biometals (IF 2.455) Pub Date : 2019-10-17
    Anna L. Greenshields, Melanie R. Power Coombs, Wasundara Fernando, Bruce E. Holbein, David W. Hoskin

    Breast cancer is a leading cause of cancer-related death in women; however, chemotherapy of breast cancer is often hindered by dose-limiting toxicities, demonstrating the need for less toxic approaches to treatment. Since the rapid growth and metabolism of breast cancer cells results in an increased requirement for iron, withdrawal of bioavailable iron using highly selective iron chelators has been suggested to represent a new approach to breast cancer treatment. Here we show that the recently developed iron-binding polymer DIBI inhibited the growth of five different breast cancer cell lines (SK-BR3, MDA-MB-468, MDA-MB-231, MCF-7, and T47D). In cultures of MDA-MB-468 breast cancer cells, which were most sensitive to DIBI-mediated growth inhibition, iron withdrawal was associated with increased expression of transferrin receptor 1 and ferritin H mRNA but decreased expression of ferroportin mRNA. MDA-MB-468 cells that were exposed to DIBI experienced double-strand DNA breaks during the S phase of the cell cycle. DNA damage was not mediated by reactive oxygen species (ROS) since DIBI-treated MDA-MB-468 cells exhibited a reduction in intracellular ROS. DIBI-treated MDA-MB-468 cells also showed increased sensitivity to growth inhibition by the chemotherapeutic drugs cisplatin, doxorubicin, and 4-hydroperoxy cyclophosphamide (active metabolite of cyclophosphamide). Combination treatment of MDA-MB-468 cells with DIBI and cisplatin caused greater DNA damage than either treatment alone, which was also associated with an increase in apoptotic cell death. Taken together, these findings suggest that DIBI-mediated iron withdrawal may enhance the effect of chemotherapeutic agents used in breast cancer treatment.

    更新日期:2019-11-04
  • Wilson disease missense mutations in ATP7B affect metal-binding domain structural dynamics
    Biometals (IF 2.455) Pub Date : 2019-10-09
    Kumaravel Ponnandai Shanmugavel, Ranjeet Kumar, Yaozong Li, Pernilla Wittung-Stafshede

    Wilson disease (WD) is caused by mutations in the gene for ATP7B, a copper transport protein that regulates copper levels in cells. A large number of missense mutations have been reported to cause WD but genotype–phenotype correlations are not yet established. Since genetic screening for WD may become reality in the future, it is important to know how individual mutations affect ATP7B function, with the ultimate goal to predict pathophysiology of the disease. To begin to assess mechanisms of dysfunction, we investigated four proposed WD-causing missense mutations in metal-binding domains 5 and 6 of ATP7B. Three of the four variants showed reduced ATP7B copper transport ability in a traditional yeast assay. To probe mutation-induced structural dynamic effects at the atomic level, molecular dynamics simulations (1.5 μs simulation time for each variant) were employed. Upon comparing individual metal-binding domains with and without mutations, we identified distinct differences in structural dynamics via root-mean square fluctuation and secondary structure content analyses. Most mutations introduced distant effects resulting in increased dynamics in the copper-binding loop. Taken together, mutation-induced long-range alterations in structural dynamics provide a rationale for reduced copper transport ability.

    更新日期:2019-11-04
  • Ytterbium increases transmembrane water transport in Zea mays roots via aquaporin modulation
    Biometals (IF 2.455) Pub Date : 2019-10-05
    Vladimir N. Vorob’ev, Timur A. Sibgatullin, Kseniya A. Sterkhova, Evgeniy A. Alexandrov, Yuri V. Gogolev, Olga A. Timofeeva, Vladimir Y. Gorshkov, Vladimir V. Chevela

    In our study, the rare earth element ytterbium (Yb3+) was demonstrated to affect water exchange in roots of Zea mays seedlings. Herewith, the overall membrane permeability (Pd) increased. The Pd increase was determined by aquaporin activity but not the membrane lipid component since the closure of aquaporin channels due to low intracellular pH abolished the positive effect of Yb3+ on Pd. Additionally, the expression level of aquaporin genes ZmPIP2;2, ZmPIP2;6 and ZmTIP2;2 was increased when plants were grown in the presence of Yb3+. Our results indicate that previously described positive influence of rare earth metals on plant growth and productivity may be mediated (at least partially) by the modification of the plant hydraulic system.

    更新日期:2019-11-04
  • Cadmium-dependent expression of a new metallothionein identified in Trichomonas vaginalis
    Biometals (IF 2.455) Pub Date : 2019-10-04
    Bryan Alexis Netzahualcoyotzi, Jonathan Puente-Rivera, Rodrigo Arreola, Julio César Torres Romero, Maximo Martínez Benitez, Rosalia Lira Carmona, Jorge Antonio Moreno Reyes, Jose de Jesús Olivares Trejo, María Elizbeth Alvarez Sánchez

    Metallothioneins (MTs) have been identified in a wide variety of organisms from bacteria to humans. The biological functions of these MTs have a key role in metalloregulatory metabolism and its expression is induced in response to different stimuli, particularly by divalent metal cations. Also, the action of MTs have been implicated in the survival of pathogens in presence of microbicidal concentration of divalent cations, which allows the establishment of the infection. Trichomonas vaginalis is a protozoan parasite that adapts to the microenvironment of the male urogenital tract, where cations such as zinc (Zn2+) and cadmium (Cd2+) are present. Nevertheless, the molecular mechanisms of metal tolerance and homeostasis is not yet dilucidated in this parasite. In this study, we have identified 4 potential MT-like sequences (tvmt´s) in T. vaginalis genome. Because tvmt-2, -3, and -4 corresponds to truncated partial genes, we characterized the trichomonad tvmt-1 gene. The bioinformatic analyses and the predicted protein (TvMT-1) show similar properties to the reported in other MTs. The expression patterns of tvmt-1 in the presence of several divalent cations (Fe2+, Mn2+, Zn2+ and Cd2+) were analyzed and we demonstrated that Cd2+ induce significantly their expression. By indirect immunofluorescence assays, we corroborated this positive regulation of TvMT-1 in the cytoplasm of parasites grown in the presence of Cd2+. The tvmt-1 promoter contains putative metal responsive elements, which are probably the responsible for the Cd2+-dependent expression of this gene. Our results suggest that tvmt-1 gene encode a metallothionein that may be responsible for the homeostatis and detoxification of Cd+2 in T. vaginalis.

    更新日期:2019-11-04
  • Protein kinase CK2 is involved in zinc homeostasis in breast and prostate cancer cells
    Biometals (IF 2.455) Pub Date : 2019-10-03
    Mohammad S. Zaman, Adam J. Johnson, Gayani Petersingham, Gerald W. Muench, Qihan Dong, Ming J. Wu

    The intracellular zinc profiles of breast and prostate cancer cells are diametrically opposed, with hyper-accumulation of zinc in breast cancer, and low level in prostate cancer. This phenomenon is poorly understood. This study employs two breast and two prostate cancer cell lines to investigate the role of protein kinase CK2 in regulating zinc homeostasis. CK2 was targeted by its specific inhibitors 4,5,6,7-tetrabromobenzotriazole (TBB) and CX-4945, and by the specific siRNA against each of the three CK2 genes. The effect of zinc exposure after the above CK2 manipulation was observed by MTT [3-(4,5-dimethyliazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] cell viability assay and confocal microscopy for intracellular zinc level. The results demonstrate that CK2 is involved in regulating zinc homeostasis in breast and prostate cancer cells as both TBB and CX-4945 substantially decreased cell viability upon zinc exposure. siRNA-mediated knockdown of the three CK2 subunits (α, α′ and β) revealed their discrete roles in regulating zinc homeostasis in breast and prostate cancer cells. Knockdown of CK2α′ decreased the intracellular zinc level of breast cancer cells and in turn increased the cell viability while the opposite findings were obtained for the prostate cancer cells. Knockdown of CK2β expression substantially increased the zinc level in breast cancer cell lines whilst decreased the zinc level in prostate cancer cells. Taken together, this study shows that CK2 is involved in zinc homeostasis of breast and prostate cancer cells and opens a new avenue for research on these cancers.

    更新日期:2019-11-04
  • The leading established metal-based drugs: a revisitation of their relevant physico-chemical data
    Biometals (IF 2.455) Pub Date : 2019-08-31
    Damiano Cirri, Maria Giulia Fabbrini, Alessandro Pratesi, Lorenzo Ciofi, Lara Massai, Tiziano Marzo, Luigi Messori

    The study of metal-based drugs represents an important branch of modern bioinorganic chemistry. The growing importance of this field is linked to the large success in medicine of a few metal based drugs, either in clinical use or still experimental. Moreover, these metal-based drugs are frequently used as reference compounds to assess comparatively the behavior of newly synthesized metallodrugs. For the convenience of researchers working in this area we report here a compilation of the relevant analytical and spectroscopic data of ten representative metallodrugs based on Platinum, Ruthenium, Gold and Mercury. The selected compounds, namely Cisplatin, Oxaliplatin, Carboplatin, Auranofin, Sodium Aurothiomalate, NAMI-A, KP1019, Thimerosal, Merbromin and Phenylmercury Acetate, were chosen owing to their importance in the field. We believe that this compilation may turn very helpful to researchers as these data are difficult to find and generally scattered over a large number of (old) publications.

    更新日期:2019-11-04
  • Bismuth(III) interactions with Desulfovibrio desulfuricans : inhibition of cell energetics and nanocrystal formation of Bi 2 S 3 and Bi 0
    Biometals (IF 2.455) Pub Date : 2019-09-23
    Larry L. Barton, Alex S. Granat, Seungyeol Lee, Huifang Xu, Nathaniel L. Ritz, Robert Hider, Henry C. Lin

    Sulfate-reducing bacteria have been suggested to have an etiological role in the development of inflammatory bowel diseases and ulcerative colitis in humans. Traditionally. bismuth compounds have been administered to alleviate gastrointestinal discomfort and disease symptoms. One mechanism by which this treatment occurs is through binding bacterial derived hydrogen sulfide in the intestines. With the addition of bismuth-deferiprone, bismuth-citrate and bismuth subsalicylate to reactions containing cells of D. desulfuricans ATCC 27774, the oxidation of H2 with sulfate as the electron acceptor was inhibited but H2 oxidation with nitrate, nitrite and sulfite was not reduced. Our research suggests that a target for bismuth inhibition of D. desulfuricans is the F1 subunit of the ATP synthase and, thus, dissimilatory sulfate reduction does not occur. At sublethal concentrations, bismuth as Bi(III) is precipitated by hydrogen sulfide produced from respiratory sulfate reduction by D. desulfuricans. Nanocrystals of bismuth sulfide were determined to be Bi2S3 through the use of high resolution transmission electron microscopy imaging with X-ray energy-dispersive spectroscopy analysis. In the absence of sulfate, D. desulfuricans oxidizes H2 with the reduction of Bi(III) to Bi0 and this was also established by X-ray energy-dispersive spectroscopy analysis.

    更新日期:2019-11-04
  • Functional analysis of recombinant buffalo lactoferrin and monoferric lobes and their cytotoxic effect on buffalo mammary epithelial cells
    Biometals (IF 2.455) Pub Date : 2019-09-25
    Surender Singh, Shalini Kalra, Parvesh Bubber, Tirtha K. Datta, Ashok K. Mohanty, Jai K. Kaushik

    Lactoferrin (Lf) has been involved in diverse type of cellular activities and its biochemical properties are species specific. Lf is a bilobal molecule in which each lobe binds with one Fe2+/Fe3+ ion. A lot of physiological effects of Lf are regulated by its iron binding and release properties; however these properties are species-specific. To understand the iron-binding, thermal stability and cytotoxic effect of buffalo Lf (buLf) and contribution of individual N- and C-terminal lobes therein, buLf and the truncated monoferric lobes were expressed in Kluyveromyces lactis or Pichia pastoris yeast expression systems. The iron-uptake/release behavior and thermal stability of recombinant buLf was observed similar to the Lf purified from buffalo milk. Supplementation of recombinant buLf to the buffalo mammary epithelial cells (BuMEC) culture decreased their proliferation and the cell viability in a dose dependent manner. The cell growth decreased by 37% at 1.0 mg/ml Lf. C-lobe decreased the viability of BuMEC by 15% at 1 mg/ml. The C-lobe showed greater cytotoxic effect against BuMEC in comparison to N-lobe. buLf caused a reduced expression of the casein in BuMEC. At 1.0 mg/ml of buLf, CSN2 transcript level was reduced by 74% and 78% in the normal and hormone free media, respectively. The expression of IL-1β gene in BuMEC increased by 4–5 fold in the presence of 1.0 mg/ml of Lf. The effect was similar to that observed in the involutory mammary gland, suggesting the role of elevated level of Lf in remodeling of buffalo mammary tissue during involution.

    更新日期:2019-11-04
  • Vanadium compounds induced damage of human umbilical vein endothelial cells and the protective effect of berberine
    Biometals (IF 2.455) Pub Date : 2019-09-24
    Cong-Cong Hou, Hong-Yu Liang, Yi-Hui Pan, Man Wang, Li-Li Zhao, Yuan Bian, Duan-Yuan Cao, Ding Zhao

    This study was conducted to investigate the damage caused by vanadium compounds and to explore the protective effects of berberine (BBR) in human umbilical vein endothelial cells (HUVECs). BBR is a biologically active small molecule found in Coptis rhizome, a remedy used in traditional Chinese medicine to treat diabetes. BBR has also been shown to lower blood glucose in diabetic patients. MTT assay was performed to observe the influence of bis(acetylacetonato)-oxidovanadium [VO(acac)2] or sodium metavanadate (NaVO3) and BBR on viability of HUVECs. The monolayer permeability of the HUVECs was assessed by measuring the transendothelial electrical resistance (TER). The endothelial nitric oxide synthase (eNOS) activity was detected by ELISA. Flow cytometry was performed to detect the generation of reactive oxygen species (ROS). The results showed that the viability of HUVECs was decreased by treatment with vanadium compounds 50–400 μM in a concentration-dependent manner, while 0.01–1 μM BBR effectively protected HUVECs from the inhibitory effects of vanadium compounds on cell viability. Also 100 and 200 μM VO(acac)2 induced high permeability and decreased eNOS activity in HUVECs. While 0.01–1 μM BBR showed no improvement in the permeability, and failed to reverse the VO(acac)2-induced changes of eNOS activity, but BBR treatment increased the eNOS activity in control cells. The addition of 200 μM VO(acac)2 significantly induced ROS generation in HUVECs, while 0.01 or 0.1 μM BBR reversed the change of ROS. In summary, BBR has protective effects in HUVECs damage induced by vanadium compounds, which is not mediated by eNOS, but related to reduced intracellular ROS.

    更新日期:2019-11-04
  • A direct comparison of divalent metal-ion transporter (DMT1) and hinokitiol, a potential small molecule replacement
    Biometals (IF 2.455) Pub Date : 2019-07-31
    Michael D. Garrick, Laura M. Garrick, Lin Zhao, James F. Collins, Joleen Soukup, Andrew J. Ghio

    Hinokitiol, a natural lipophilic chelator, appears capable of replacing several iron transporters after they have been genetically ablated. Divalent metal-ion transporter (DMT1) is the major iron importer in enterocytes and erythroblasts. We have compared DMT1 and hinokitiol in multiple fashions to learn if the smaller molecule is a suitable substitute using two HEK293 cell lines engineered to overexpress different isoforms of DMT1. Both the macromolecule and the lipophilic chelator enable import of ferrous ions into HEK293 cells. Hinokitiol also mediates ferric ion import but DMT1 cannot do so. While DMT1 can also import Mn2+ ions, hinokitiol lacks this ability. The Michaelis–Menten analysis for kinetics of macromolecular catalysis is also suitable for hinokitiol-supported iron import. To compare hinokitiol to DMT1 relative to other metal ions that DMT1 can transport, we employed an organic extraction procedure with which we initially matched the results obtained for Fe2+, Fe3+ and Mn2+, and then showed that multiple other cations were unlikely to enter via hinokitiol. The small chelator thus shares some functional properties with DMT1, but distinct difference were also noted.

    更新日期:2019-11-04
  • Reactive oxygen species, auxin and nitric oxide in metal-stressed roots: toxicity or defence
    Biometals (IF 2.455) Pub Date : 2019-09-21
    Loriana Demecsová, Ladislav Tamás

    The presented review is a summary on the current knowledge about metal induced stress response in plants, focusing on the roles of reactive oxygen species, auxin and nitric oxide in roots. The article focuses mainly on the difference between defence and toxicity symptoms of roots during metal-induced stress. Nowadays, pollution of soils by heavy metals is a rapidly growing issue, which affects agriculture and human health. In order to deal with these problems, we must first understand the basic mechanisms and responses to environmental conditions in plants growing under such conditions. Studies so far show somewhat conflicting data, interpreting the same stress responses as both symptoms of defence and toxicity. Therefore, the aim of this review is to give a report about current knowledge of heavy metal-induced stress research, and also to differentiate between toxicity and defence, and outline the challenges of research, focusing on reactive oxygen and nitrogen species, auxin, and the interplay among them. There are still remaining questions on how reactive oxygen and nitrogen species, as well as auxin, can activate either symptoms of toxicity or defence, and adaptation responses.

    更新日期:2019-11-04
  • Novel contrast media based on the liquid metal gallium for in vivo digestive tract radiography: a feasibility study
    Biometals (IF 2.455) Pub Date : 2019-09-25
    Huan Liu, Yang Yu, Wei Wang, Ying Liu, Yonghui An, Qian Wang, Jing Liu

    The barium sulfate has been playing an important role as the contrast medium in gastrointestinal radiography and disease diagnosis. However, its application has been gradually reduced due to the limitation of its imaging effect and the progress of other imaging techniques. Here, the liquid metal gallium was proposed as an improved contrast agent, which was applied in the in vivo digestive tract radiography of the mice for the first time. Under the CT scanning, the gallium produced excellent contrast effect intuitively. According to the records of discharge time, the tissue sections of organs, the survival state and body weight, the liquid metal was proven to be capable and safe for gastrointestinal radiography. Further, the mixture of the gallium and the barium sulfate has been tested, which showed better performance in both contrast and detail. Therefore, with the characteristics of better imaging contrast effect and acceptable safety, the gallium and its mixture with the barium sulfate might be useful as potential candidates for digestive tract contrast agent in animal experiments, even possibly as alternative contrast agents for clinical use.

    更新日期:2019-11-04
  • Molecular cloning, expression and characterization of secreted ferritin in the silkworm, Bombyx mori
    Biometals (IF 2.455) Pub Date : 2019-07-30
    Yang Zhou, Xiao-Dong Yuan, Jing-Chi Wang, Hai-Tao Liu, Frank Addai Peprah, Ting-Ya Jiang, Jie Gu, Hai-Feng Shi

    Ferritin is a ubiquitous iron storage protein which plays key role in regulating iron homeostasis and metabolism. In this paper, the ferritin heavy chain homologs (HCH) and light chain homologs (LCH) from Bombyx mori (BmFerHCH and BmFerLCH) were amplified through PCR and cloned into the expression vector pET-30a(+). The recombinant BmFerHCH and BmFerLCH expressed in Escherichia coli were in the form of insoluble inclusion bodies, indicating that the two proteins were not in their natural structural conformation. In order to obtain refolded ferritin in vitro, the inclusion bodies (BmFerHCH and/or BmFerLCH) were dissolved in denaturing buffer (100 mM Tris, 50 mM Glycine, 8 M urea, 5 mM DTT, pH 8.0) and then refolded in refolding buffer (100 mM Tris, 400 mM l-arginine, 0.2 mM PMSF, 0.5 mM DTT). The result showed that it was only when both BmFerHCH and BmFerLCH were present together in the denaturing buffer that refolding was successful and resulted in the formation of heteropolymers (H–L chain dimers) over homopolymers (H–H chain or L–L chain dimers). Moreover, the molecules (NaCl, Triton and glycerol) were found to enhance protein refolding. The optimum temperature, pH and ratios of BmFerHCH/BmFerLCH required for refolding were found to be 10 °C, pH 7, 1:1 or 1:2, respectively. Finally, the refolded ferritin had the ability to store iron, exhibited ferroxidase activity, and could withstand high temperatures and pH treatment, which is consistent with ferritin in other species.

    更新日期:2019-11-04
  • Zinc deficiency alters the susceptibility of pancreatic beta cells (INS-1) to arsenic exposure
    Biometals (IF 2.455) Pub Date : 2019-09-21
    Annie L. Cao, Laura M. Beaver, Carmen P. Wong, Laurie G. Hudson, Emily Ho

    Pancreatic beta cells produce and release insulin, a hormone that regulates blood glucose levels, and their dysfunction contributes to the development of diabetes mellitus. Zinc deficiency and inorganic arsenic exposure both independently associate with the development of diabetes, although the effects of their combination on pancreatic beta cell health and function remain unknown. We hypothesized zinc deficiency increases the toxicity associated with arsenic exposure, causing an increased susceptibility to DNA damage and disruption of insulin production. Zinc deficiency decreased cell proliferation by 30% in pancreatic INS-1 rat insulinoma cells. Arsenic exposure (0, 50 or 500 ppb exposures) significantly decreased cell proliferation, and increased mRNA levels of genes involved in stress response (Mt1, Mt2, Hmox1) and DNA damage (p53, Ogg1). When co-exposed to both zinc deficiency and arsenic, zinc deficiency attenuated this response to arsenic, decreasing the expression of Mt1, Hmox1, and Ogg1, and significantly increasing DNA double-strand breaks 2.9-fold. Arsenic exposure decreased insulin expression, but co-exposure did not decrease insulin levels beyond the arsenic alone condition, but did result in a further 33% decline in cell proliferation at the 500 ppb arsenic dose, and a significant increase in beta cell apoptosis. These results suggest zinc deficiency and arsenic, both independently and in combination, adversely affect pancreatic beta cell health and both factors should be considered in the evaluation of health outcomes for susceptible populations.

    更新日期:2019-11-04
  • H-Aquil: a chemically defined cell culture medium for trace metal studies in Vibrios and other marine heterotrophic bacteria
    Biometals (IF 2.455) Pub Date : 2019-09-21
    Donald E. Martocello, François M. M. Morel, Darcy L. McRose

    A variety of trace metals, including prominently iron (Fe) are necessary for marine microorganisms. Chemically defined medium recipes have been used for several decades to study phytoplankton, but similar methods have not been adopted as widely in studies of marine heterotrophic bacteria. Medium recipes for these organisms frequently include tryptone, casamino acids, as well as yeast and animal extracts. These components introduce unknown concentrations of trace elements and organic compounds, complicating metal speciation. Minimal medium recipes utilizing known carbon and nitrogen sources do exist but often have high background trace metal concentrations. Here we present H-Aquil, a version of the phytoplankton medium Aquil adapted for marine heterotrophic bacteria. This medium consists of artificial seawater supplemented with a carbon source, phosphate, amino acids, and vitamins. As in Aquil, trace metals are controlled using the synthetic chelator EDTA. We also address concerns of EDTA toxicity, showing that concentrations up to 100 µM EDTA do not lead to growth defects in the copiotrophic bacterium Vibrio harveyi or the oligotrophic bacterium Candidatus Pelagibacter ubique HTCC1062, a member of the SAR11 clade. H-Aquil is used successfully to culture species of Vibrio, Phaeobacter, and Silicibacter, as well as several environmental isolates. We report a substantial decrease in growth rate between cultures grown with or without added Fe, making the medium suitable for conducting Fe-limitation studies in a variety of marine heterotrophic bacteria.

    更新日期:2019-11-04
  • ZIP14 is degraded in response to manganese exposure
    Biometals (IF 2.455) Pub Date : 2019-09-20
    Khristy J. Thompson, Marianne Wessling-Resnick

    Manganese (Mn) is an essential element necessary for proper development and brain function. Circulating Mn levels are regulated by hepatobiliary clearance to limit toxic levels and prevent tissue deposition. To characterize mechanisms involved in hepatocyte Mn uptake, polarized human HepaRG cells were used for this study. Western blot analysis and immunofluorescence microscopy showed the Mn transporter ZIP14 was expressed and localized to the basolateral surface of polarized HepaRG cells. HepaRG cells took up 54Mn in a time- and temperature-dependent manner but uptake was reduced after exposure to Mn. This loss in transport activity was associated with decreased ZIP14 protein levels in response to Mn exposure. Mn-induced degradation of ZIP14 was blocked by bafilomycin A1, which increased localization of the transporter in Lamp1-positive vesicles. Mn exposure also down-regulated the Golgi proteins TMEM165 and GPP130 while the ER stress marker BiP was induced. These results indicate that Mn exposure decreases ZIP14 protein levels to limit subsequent uptake of Mn as a cytoprotective response. Thus, high levels of Mn may compromise first-pass-hepatic clearance mechanisms.

    更新日期:2019-11-04
  • Genome-wide analysis of zinc- and iron-regulated transporter-like protein family members in apple and functional validation of ZIP10
    Biometals (IF 2.455) Pub Date : 2019-06-19
    Xiaocen Ma, Heng Liu, Huairong Cao, Ruyu Qi, Kuo Yang, Rongrong Zhao, Wei Lv, Yuanhu Zhang

    Deficiency of zinc (Zn) and iron (Fe) is common in apple grown in orchards, which affects fruit yield and quality. However, the mechanisms of absorption and transport of Zn and Fe in apples are still unclear. In the present study, we aimed to identify MdZIP genes and explore the mechanism of response of MdZIPs to Zn and Fe deficiencies. Eighteen Zn- and Fe-regulated transporter-like protein (ZIP) family members were identified in apple (Malus domestica L.) and named according to their chromosomal location. Phylogenetic analysis divided MdZIPs into four groups, and the most closely related MdZIPs in the phylogenetic tree showed similar gene structures and protein motifs. Expression pattern analysis indicated that ZIP genes in apple were differentially expressed among tissues and developmental stages under Zn and Fe deficiency. The overexpression of MdZIP10 increased the content of Zn and Fe in Arabidopsis thaliana L. and MdZIP10 played crucial roles in the uptake and transport of Zn and Fe. MdZIP10 was able to rescue growth of Zn2+ and Fe2+ uptake defective yeast mutants under Zn2+ and Fe2+ deficient conditions, respectively. Symptoms of Zn and Fe deficiency were alleviated in the MdZIP10 transgenic plants. The expression of genes related to Fe and Zn uptake and transport was induced in the MdZIP10 transgenic plants, thereby stimulating endogenous Fe and Zn uptake and transport mechanisms. The present study lays the foundation for future functional analysis of ZIP genes in apple.

    更新日期:2019-11-04
  • Synthesis, structural elucidation and antiradical activity of a copper (II) naringenin complex
    Biometals (IF 2.455) Pub Date : 2019-03-25
    Gustavo Celiz, Sebastián A. Suarez, Analía Arias, José Molina, Carlos D. Brondino, Fabio Doctorovich

    Coupling the extraction and derivatization of flavonoids to the Citrus processing industry is attractive from both the environmental and economic points of view. In the present work, the flavonoid naringin, obtained by “green” extraction with a water:ethanol mixture from waste grapefruit industry, was hydrolyzed to obtain naringenin. This flavonoid was used to synthesize the complex trans-di(aqua) bis(7-hydroxy-2-(4-hydroxyphenyl)-4-oxo-5-chromanolato) copper (II). This compound was characterized by spectroscopic techniques (UV/Vis, IR, Raman, NMR and EPR), and by thermal analysis (TG and DSC). Then, a monocrystal of the complex obtained by dissolution and recrystallization in DMF was analyzed by single crystal X-ray diffraction. This is the first report of the crystal structure of a Citrus flavonoid complex. Additionally, its antiradical activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) was determined and compared with that for naringenin, demonstrating that coordination to copper enhances the antiradicalar activity of naringenin. According to the Mulliken population analysis conducted, by copper favors the delocalization and stabilization of the produced radical, since it acts as an electronic density acceptor.

    更新日期:2019-11-04
  • A key gene bHLH115 in iron homeostasis: comprehensive bioinformatics analyses in Arabidopsis , tomato, rice, and maize
    Biometals (IF 2.455) Pub Date : 2019-05-06
    Fırat Kurt, Ertugrul Filiz, Barıs Kurt

    bHLH115 transcription factor (TF) is a positive regulator of the Fe-deficiency and plays essential roles in the stress-related regulation network. In this study, orthologous bHLH115 genes in Arabidopsis, tomato, rice, and maize were analyzed using in silico methods. All bHLH115 proteins contained PF00010 (HLH: Helix-loop-helix DNA-binding domain) domain structure and their sub-cellular localizations were predicted as nucleus. The bHLH115 orthologues in monocots and dicots clearly diverged from each other. The expression analyses revealed that orthologous genes of bHLH115 in queried species were highly expressed in seed parts, leaf, stem, and flower parts. The bHLH115 genes were co-expressed with genes in plant defense system, and with genes involving in biotic and abiotic stress responses. In terms of protein structures, OsbHLH115 and ZmbHLH115, and AtbHLH115 and SlbHLH115 had the highest protein structure similarities. In addition, bHLH115 proteins have bZIP, bHLH and MYB transcription factor binding sites strengthens their engagement in various metabolic ways. Molecular docking analyses showed the different binding sites based on plant species, suggesting functional flexibilities of bHLH115 gene.

    更新日期:2019-11-02
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