Metallomics Research Research Articles

The influence of physiological and lifestyle factors on essential mineral element isotopic compositions in the human body: implications for the design of isotope metallomics research.

In the last 20 years, the application of high-precision isotopic analysis of essential mineral elements (Mg, K, Ca, Fe, Cu, and Zn) to biomedicine (sometimes referred to as isotope metallomics) has revealed that their stable isotopic compositions are altered by the metal dysregulation that is fundamental to the pathogenesis of many cancers and other diseases. Despite many published works showing the diagnostic and prognostic potential of this approach, a number of factors that may influence the stable isotopic composition of these essential mineral elements in healthy individuals remain unstudied. In this perspective article, we summarize the available evidence from trophic level studies, animal models, and ancient and modern humans, relating to physiological and lifestyle factors that appear likely (there is evidence indicating their influence) or unlikely (there is evidence indicating their lack of influence) to require controlling for when investigating variations in essential mineral element isotopic compositions in human subjects. We also discuss factors that require additional data to properly assess. There is evidence that sex, menopausal status, age, diet, vitamin and metal supplementation, genetic variation, and obesity influence the isotopic composition of at least one essential mineral element in the human body. The task of investigating potential influences on essential mineral element isotopic compositions in the human body is sizeable, but presents an exciting research opportunity, with each incremental advance helping to improve the quality of research output in the context of isotope metallomics.

Recent Advances in ICP-MS Analysis for Metallomics Research of Heart and Kidney Diseases

Recent Advances in ICP-MS Analysis for Metallomics Research of Heart and Kidney Diseases

Two-dimensional (weak anion exchange chromatography-gel electrophoresis) separations coupling to inductively coupled plasma mass spectrometry strategy for analysis of metalloproteins

A two-dimensional (2-D, weak anion exchange chromatography-gel electrophoresis, WAX-GE) separations coupling to inductively coupled plasma mass spectrometry (ICP-MS) strategy was developed for efficient tracking of metalloproteins. Samples were fractionized with the primary dimension (WAX) and the collected fractions were subsequently subjected to the secondary dimension (GE) and finally detected with ICP-MS. The metalloproteins of interest from the secondary dimension were online split and collected for further manipulation. The molecular weight of metalloprotein was calibrated with a home-made protein marker including six iodine-labelled proteins with molecular weights ranging from 14 kDa to 77 kDa. The developed 2-D system is of higher separation resolution as compared to one-dimensional (1-D) system. Metalloproteins in Escherichia coli were further examined for validation of the method preformation. Several known or unknown metal-associated proteins were identified, evidencing the feasibility of the proposed method. Taken together, we established a solid methodology for efficient separation and qualitative study of metalloproteomics, providing a new strategy for the metallomics research.

New Frontiers of Metallomics: Elemental and Species-Specific Analysis and Imaging of Single Cells.

Single cells represent the basic building units of life, and thus their study is one the most important areas of research. However, classical analysis of biological cells eludes the investigation of cell-to-cell differences to obtain information about the intracellular distribution since it only provides information by averaging over a huge number of cells. For this reason, chemical analysis of single cells is an expanding area of research nowadays. In this context, metallomics research is going down to the single-cell level, where high-resolution high-sensitive analytical techniques are required. In this chapter, we present the latest developments and applications in the fields of single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS), mass cytometry, laser ablation (LA)-ICP-MS, nanoscale secondary ion mass spectrometry (nanoSIMS), and synchrotron X-ray fluorescence microscopy (SXRF) for single-cell analysis. Moreover, the capabilities and limitations of the current analytical techniques to unravel single-cell metabolomics as well as future perspectives in this field will be discussed.

Development of metallomics research on environmental toxicology

Metallomics is newly coined terms and defined as a comprehensive analysis of the entirety of metal and metalloid species within a cell or tissue type. Then, metallome is defined as the entire category of metalloproteins and any other metal-containing biomolecules. Metallomics and research on metallome require analytical techniques that can provide information on the identification and quantification of metal/metalloid-containing biomolecules. This concept has been called speciation, and the acquisition of data according to the concept is performed using hyphenated techniques involving both separation and detection methods. In this review, the author intends to present several applications of complementary use of HPLC-inductively coupled plasma mass spectrometry (ICP-MS) and HPLC-electrospray ionization tandem mass spectrometry for identification of unknown selenium-containing metabolites, and also to present a newly developed technique, capillary LC-ICP-MS to be used for the analysis of metal-binding proteins.

Chip-based array magnetic solid phase microextraction on-line coupled with inductively coupled plasma mass spectrometry for the determination of trace heavy metals in cells.

Determination of trace elements in cells is critical to metallomics research and still faces tremendous difficulties even with the help of highly sensitive inductively coupled plasma mass spectrometry (ICP-MS). Microfluidic chips offer a functional tool-set for cell analysis with features of miniaturization, integration and automation. In this work, we proposed a chip-based array magnetic solid phase microextraction (MSPME) system and on-line combined it with ICP-MS via microflow concentric nebulization for the determination of trace Cu, Zn, Cd, Hg, Pb and Bi in cells. Under the optimized conditions, the limits of detection of the developed on-line chip-based array MSPME-ICP-MS system are 49, 43, 4.2, 6.1, 13 and 18 ng L(-1) for Cu, Zn, Cd, Hg, Pb and Bi, respectively. The proposed method was applied to the analysis of target heavy metals in three kinds of cells (HepG2, Jurkat T and MCF7), and the recoveries for the spiked samples were in the range of 83.8%-117%. The extractable species of the target metals in cells were also studied and the results demonstrated a high selectivity of the developed methods towards free metal ions and/or their small molecular species.

Chip-based liquid phase microextraction combined with electrothermal vaporization-inductively coupled plasma mass spectrometry for trace metal determination in cell samples

Metal determination in precious biological samples is critical to metallomics research. Microfluidic chips provide an excellent platform for the miniaturization of extraction. In this work, a chip-based liquid phase microextraction (chip-based LPME) device was fabricated and combined with electrothermal vaporization-inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of trace Cu, Zn, Cd, Hg, Pb and Bi in cell samples and human serum samples. With sodium diethyldithiocarbamate (DDTC) as both the chemical modifier for low-temperature ETV-ICP-MS and the extracting reagent for the chip-based LPME, the chip parameters influencing the extraction efficiency including central channel width, branch channel ratio and central channel length were optimized by orthogonal design experiments. Under the optimized conditions, the limits of detection (LODs) are in the range of 6.6–89.3 pg mL−1 with the RSDs ranging from 4.23–8.15% (n = 7, c = 1 ng mL−1) for the target metal ions. The linear range covers three magnitudes with correlation coefficients higher than 0.99. The proposed method was validated by analyzing the target metal ions in certified reference materials of GBW07605 human hair and GBW09152 human serum, and metal determination in HepG2 cells, Jurkat T cells and a human serum sample were achieved with the recoveries in the range of 86.6–119%. The developed method is fast, has a low sample and reagent consumption and is highly sensitive, thus it is quite suitable for the analysis of precious biological samples such as cells.

New Development of Metallomics Research Based on the Speciation

New Development of Metallomics Research Based on the Speciation

Epigenetics: an important challenge for ICP-MS in metallomics studies

Trace metal analysis has been long regarded as one of the principle tasks in areas of chemical analysis. At the early stage of instrumental development, total concentration was assessed in a variety of samples, yielding results, among others, for environmental, biological, and clinical samples. With the power of newer analytical techniques, such as inductively coupled plasma mass spectrometry (ICP-MS), accurate quantitative results can now be obtained at ultra-trace levels not only for metals, but also for metalloids and several non-metals. Even though the importance of trace elements in many biological processes is widely accepted, the elucidation of their biological pathways, understanding specific biological functions, or possible toxicological aspects is still a challenge and a driving force to further develop analytical methodology. Over the past decades, the scientific interest has moved from total element determination to include speciation analysis, which provides quantitative information of one or more individual element species in a sample. More recently, metallomics has been introduced as a more expanded concept, in which the global role of all metal/metalloids in a given system is considered. Owing to the multi-elemental focus of metallomics research, the use of ICP-MS becomes indispensable. Furthermore, considering the biological role of metals/metalloids and the use of elements as internal or external molecular tags, epigenetics should be considered as an important emerging application for metallomics studies and approaches. Among a variety of epigenetic factors, essential nutrients, but also environmental toxins, have been shown to affect DNA methylation, modification of histone proteins, and RNA interference, all of them being implicated in cancer, cardiovascular disease, and several inherited conditions. Recent studies suggest that epigenetics may be a critical pathway by which metals produce health effects. In this Trends article, the basic epigenetic concepts are introduced, followed by the early applications of ICP-MS classified as: (i) detection of (31)P as a natural element tag for DNA, (ii) analysis of DNA adducts with metal-based drugs, (iii) element species as epigenetic factors.

Preface

Abstract The International Symposium on Metallomics 2007 (ISM 2007), was held in Nagoya, Japan 28 November-1 December 2007. This event was organized by the Chemical Society of Japan, with sponsorship of IUPAC, in order to highlight a newly emerging scientific concept. The term "metallomics" was proposed in 2004 to describe integrated biometal science, and has been receiving growing attention because it embraces all research fields related to metals in biological systems. A better understanding of the distribution, biological roles and functions, and physiological regulation and metabolism of metals in biological systems demands interdisciplinary cooperation between scientists in a variety of fields, such as chemistry, physics, biology, medicine, pharmacy, and agriculture. Metallomics can thus be expected to play a more widely recognized role in health, the environment, nutrition, food, toxicology, public hygiene, and bioremediation, to name just a few societally important application areas. Furthermore, the development of metallomics as a scientific field complements genomics and proteomics, and contributes toward more comprehensive insights into life processes. This first International Symposium on Metallomics was attended by about 340 delegates from 30 counties. The scientific program comprised 98 oral presentations including 6 plenary, 15 keynote, and 35 invited lectures, and 124 poster presentations. The proceedings covered a broad range of topics, which were delineated as - metallomics research on (a) environment and metals, (b) metallotoxicology, (c) health and food/nutrition, and (d) plants and metals; - metallomics research combined with genomics and proteomics; - advanced technologies for trace analysis; - chemical speciation of bio-trace elements; - bioimaging and biosensing technologies; - bioinorganic chemistry of metalloproteins and metalloenzymes; - biological regulation of metals and their mechanisms of metabolism; - drug design and chemotherapy of bioinorganic medicine; - medical diagnosis of health and disease; and - development of standard reference materials for biological, clinical, and environmental analysis. The program thus provided a comprehensive overview of all aspects of current interest and activity in metallomics, and it is hoped that this collection of works from the scientific proceedings will serve as a valued record and a source of future inspiration. It is a pleasure to report that the Royal Society of Chemistry, UK, will launch a new journal entitled Metallomics - Integrated Biometal Science from January 2009 (http://www.rsc.org/Publishing/Journals/mt/index.asp), which will help to stimulate ongoing development and facilitate the exchange of information in the metallomics community. Professor Joe Caruso (Cincinnati University) will serve as editor-in-chief. An important outcome of this inaugural event is that the International Advisory Board has decided to launch a biennial series of symposia on Metallomics, and that ISM 2009 will take place in Cincinnati, USA during June 2009 under the chairmanship of Prof. Caruso. In conclusion, it is with sorrow that we report the sudden death of Prof. Kazuo T. Suzuki (Chiba University, Japan) on 15 July 2008, whilst the editorial work for this special issue was in progress. He was Co-chair of the Organizing Committee for ISM 2007 and, as one of the world leaders in this field, presented a plenary lecture on that occasion. We mourn his passing and remember his outstanding contributions to science. This will be the subject of a memorial lecture, which I expect to deliver during ISM 2009. Hiroki Haraguchi Conference Editor and Chairman

Assay of Alkaline Phosphatase in Salmon Egg Cell Cytoplasm with Fluorescence Detection of Enzymatic Activity and Zinc Detection by ICP-MS in Relation to Metallomics Research

Abstract Assay of alkaline phosphatase (ALP) in salmon egg cell cytoplasm was performed by size exclusion chromatography (SEC) with fluorescence detection of enzymatic activity and element-selective detection of zinc by ICP-MS, where 4-methylumbelliferyl phosphate (4-MUP) was used as the substrate for the enzymatic reaction of ALP. Two peaks were observed at retention times of ca. 21 and 27 min in the fluorescence-detected SEC chromatogram for salmon egg cell cytoplasm diluted 10-fold with 0.1 M Tris-HNO3 buffer solution, corresponding to the molecular weights (MWs) of ≥300 and 100 kDa, respectively. On the other hand, in the 66Zn-detected chromatogram for the same sample, a broad peak with a shoulder on the side of longer retention time was observed at ca. 21 min (MW≥300 kDa). When salmon egg cell cytoplasm was diluted 10-fold with pure water or 0.01 M Tris-HNO3 buffer solution, precipitation occurred. The supernatant obtained after filtration produced only one clear peak at a retention time of ca. 27 min in the fluorescence-detected chromatogram, at which the peak corresponding to zinc was also observed in the Zn-detected chromatogram. Therefore, the peak near 27 min was assigned to hydrophilic ALP in the salmon egg cell cytoplasm. Furthermore, the concentration of hydrophilic ALP (MW ca. 100 kDa) in the salmon egg cell cytoplasm was about 350 ng g−1, which was determined as an E. coli ALP-equivalent concentration by fluorescence intensity measurements.

Speciation of mercury in salmon egg cell cytoplasm in relation with metallomics research

Speciation of mercury in salmon egg cell cytoplasm was investigated by surfactant-mediated high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICP-MS), where an ODS (octadecylsilica) column coated with a bile acid derivative, CHAPS (3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate), was used for species separation. Prior to the speciation analysis, total Hg in the cell cytoplasm was determined by ICP-MS at m/ z 202 in a flow injection mode. For the precise measurement, salmon egg cell cytoplasm was diluted five-fold with 0.1 M Tris (Tris(hydroxymethyl)aminomethane)–HNO 3 buffer solution, and the standard addition method was employed. Thus, the total concentration of Hg in cell cytoplasm was estimated to be 12.4 ng g −1 on the wet weight basis. Next, the cell cytoplasm diluted five-fold with 0.1 M Tris–HNO 3 buffer solution was analyzed by surfactant-mediated HPLC with the dual detection system of a UV absorption detector and an ICP-MS instrument. Two peaks corresponding to some proteins and small molecules were mainly observed in those chromatograms. When salmon egg cell cytoplasm was diluted five-fold with 0.01 M Tris buffer solution or pure water, some precipitates appeared probably because of precipitation of hydrophobic proteins in cytoplasm. After the precipitates were eliminated with a membrane filter, the filtrate was subjected to the analysis by surfactant-mediated HPLC/UV/ICP-MS. As a result, the peaks for small molecular species of Hg were clearly observed at the retention time near 4.0 min (corresponding to low-molecular weight zone) in the chromatograms with UV absorption detection as well as with Hg- and S-specific ICP-MS detections. The small molecule bound with Hg was identified as cysteine through the cysteine-spiked experiment. In addition, the protein fraction on the chromatogram obtained by using the CHAPS-coated ODS column was further analyzed by SEC (size exclusion chromatography). Consequently, several protein peaks with molecular weight of 300, 50 and 12 kDa were observed in all the detections of UV absorption, Hg and Se, although two peaks among them were coincident in the case of S. These results indicate that Hg in salmon egg cell cytoplasm binds with proteins containing selenocysteine and/or cysteine residues in proteins.

New Development of Chemical Speciation Analysis for Metallomics Research

New Development of Chemical Speciation Analysis for Metallomics Research