Special Issue "Selenium and Tellurium Chemistry"

Guest Editor
Dr. Rudolf Pietschnig
Karl-Franzens-Universität, Institut für Chemie, Anorganische Chemie, Schubertstrasse 1, A-8010 Graz, Austria
E-mail:

selenium, tellurium, chalcogene, organoselenium, organotellurium, selenoproteins, selenium-enrichment, selenium speciation, selenium bioavailability, toxicology, selenide, telluride, selenite, tellurite, heterocycles, gas phase deposition, CVD, molecular magnets, materials, 77Se nmr, chalcogen clusters, chalcogen ions, crystal structures

Title: Role of Selenium in Vascular Health and Disease
Authors: Lorraine M. Sordillo*, Chris M. Corl, and Stacey L. Aitken
*Corresponding author: Lorraine M. Sordillo, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824
E-mail: sordillo@msu.edu
Abstract: Selenium is an essential trace element that is known to play a beneficial role in both human and animal health. Considerable epidemiologic data exists to support the concept that various forms of selenium can protect against many types of cancers, cardiovascular diseases, and several other inflammatory-based diseases. The metabolism of selenium in mammals is determined largely by the dietary sources (organic or inorganic) and most of the protective effects of selenium are postulated to be due to either its metabolism into methylated selenocompounds or its incorporation into selenoproteins. Endothelial cell dysfunction is linked with the development of many diseases and one way that selenium may influence health is by the ability to maintain vascular homeostasis. This review will describe the potential molecular mechanisms of how selenocompounds and selenoproteins can impact vascular function and mammalian health.

Manuscript ID: molecules-selenium-20081028-jp-Sugimoto
Type of paper: Review
Tentative title: Selenium-Substituted Ethylenedithiotetrathiafulvalenothioquinone-1,3-dithiolemethide Donor Molecules
Authors: Toyonari Sugimoto *, Toshiki Hayashi, Xunwen Xiao, Yuhta Yamaji and Xiangfeng Shao
Affiliation: Department of Chemistry, Graduate School of Science,
Osaka Prefecture University
Abstract: Ethylenedithiotetrathiafulvalenothioquinone-1,3-dithiolemethide and its quinone derivative are such useful donor molecules that their charge-transfer (CT) salts with magnetic FeX4- (X = Cl, Br) ions give one ferromagnetic molecular semiconductor and four antiferromagnetic molecular metals with significant p-d interaction between conducting p electrons and localized d spins. A selenium atom has a larger van der Waals radius than oxygen and sulfur atoms, so selenium-substituted derivatives of the thioquinone and quinone donor molecules are expected to bring about much more stabilization of metallic state as well as stronger p-d interaction, by which an unprecedented ferromagnetic molecular metal working at reasonable temperatures could be realized. The sulfur atoms at different positions of the thioquinone donor molecule are substituted with selenium atoms using newly-developed synthetic methods to give new donor molecules with an ethylenediselena group in place of an ethylenedithio group, with a selenone group in place of a thione group, with 1,3-diselenole group in place of a 1,3-dithiole group and with selenium atoms in place of some of four sulfur atoms in a central tetrathiaethylene group, respectively. This review summarizes molecular structures and pysical properties of thses selenium donor molecules, and also crystal structures and electrical conducting/magnetic properties of their CT salts with FeX4- ions.

Manuscript ID: molecules-selchem-20081103-cy-Odysseos
Type of Paper: Review
Title: Selenium in Cancer Prevention and Therapeutics: One Element, many Targets
Author: Andreani D.Odysseos
Affiliation: EPOS-Iasis, R&D, Nicosia, Cyprus
E-mail: andreani@epos-iasis.com
Abstract: The past decade has experienced the evolution of a promising group of selective agents comprised of organic Selenium compounds. Eventhough the critical Se metabolite hypothesis has steadily gained both in vivo and in vitro support, much remains debatable as to what mechanisms account for the cancer preventive activity of Selenium. This review highlights the propensities of these agents to modulate critical signals and affect selectively a multitude of molecular targets in premalignant and malignant lesions. It further provides an insight into how modifications of their structural characteristics may alter dramatically their biological activities due to the evolution of signal-generating active intermediates and metabolites. Mechanisms address key elements such as the organ site specificity, the selectivity against transformed phenotype, the forms and effective doses of Se and the responsive carcinogenesis stages and molecular targets.

Manuscript ID: molecules-selenium-20081107-be-Pussemier
Type of Paper: Review
Title: Selenium Speciation and Bioavailability in Food.
Authors: Thiry Céline ¹, Ludwig De Temmerman ¹, Yves-Jacques Schneider ² and Luc Pussemier ^1,*
Affiliations: ¹ CODA-CERVA-VAR, Veterinary and Agrochemical Research centre, Leuvensesteenweg, 17, B 3080 Tervuren
² Biochimie cellulaire, nutritionnelle & toxicologique, Institut des Sciences de la Vie & Université catholique de Louvain, Croix du Sud, 5, B 1348 Louvain-la-Neuve
E-mail: Luc.Pussemier@var.fgov.be
Abstract: It is known that an increase of the selenium consumption in case of a low-selenium diet decreases the risk of cancer, and this is because of the antioxidative and anticarcinogenic properties of this element. Selenium, however, becomes toxic when ingested in too large amount. In Europe, the recommended selenium dietary intake is rarely reached by the population, and this is why dietary supplements and selenium-enriched food appear on the market. In this review, we summarize the techniques used and the results obtained up to now about selenium speciation and selenium bioavailability taking into account the chemical forms actually present in foodstuffs.

Manuscript ID: molecules-selchem-20081112-sk-Breierova
Type of Paper: Article
Title: Effect of Selenium on Lipid Alterations in Pigment-forming Yeasts
Authors: Milan Čertík ¹, Emília Breierová ², Monika Oláhová ¹, Vladimíra Hanusová ¹
Affiliations: ¹Department of Biochemical Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovak Republic
²Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38 Bratislava, Slovak Republic
E-mail: chememi@savba.sk
Abstract: The work deals with growth and lipid modifications of pigment-forming yeasts of genus Rhodotorula and Sporobolomyces growing under presence of selenium. Addition of this metal to the medium significantly prolonged lag-phase of all cultures and enlarged yeast cells. Total lipids, neutral lipids and the main membrane lipids (phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol) of investigated yeasts consisted of mainly palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C 18:1), linoleic (C18:2) and linolenic (C18:3) acids. Oleic acid was the main fatty acid almost in all investigated lipid structures, palmitic and stearic acids were also abundant in phosphatidylserine and phosphatidylinositol. It was found that neutral lipids (primarily triacylglycerols) did not show such intensive changes in fatty acid composition as their polar counterparts. Generally, phosphatidylcholine displayed the highest amounts of C18 unsaturated fatty acids in all investigated yeasts. However, fatty acid profile in polar lipids varied according to individual lipid structure and selenium presence in the medium. Selenium increased levels of both linoleic and linolenic acids in all strains. It resulted in enhanced index of fatty acid unsaturation in phosphatidylcholine and phosphatidylethanolamine. Thus, selenium might be either involved to the induction of membrane-bound fatty acid D¹² and D¹⁵ fatty acid desaturases or these fatty acid desaturases reflect the adaptation changes of yeasts grown under selenium and regulate optimal physical properties of the membrane fluid bilayer in stressed yeasts.

Manuscript ID: molecules-selchem-20081227-jp-Hada
Type of Paper: Article
Title: Excitation and Circular Dichroism Spectra of (+)-(S,S)-bis(2-methylbutyl)chalcogenide: SAC and SAC-CI calculations
Authors: Yasushi Honda and Masahiko Hada
Affiliations: Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University
E-mail: hada@tmu.ac.jp
Abstract: Theoretical electronic spectra and natural circular dichroism (CD) spectra of (+)-(S,S)-bis(2-methylbutyl)chalcogenide, Ch[CH2CH(CH3)C2H5]2 (Ch = S, Se, Te), were calculated by the symmetry adapted cluster (SAC) and SAC-configuration interaction (SAC-CI) methods. Whereas the calculated CD spectrum for each stable conformation itself did not reproduce the corresponding experimental one, their Boltzmann-averaged spectra showed good agreement with the experimental results. We provided the assignment for each spectral band according to our calculation results. For the telluride compound, temperature dependence of the CD spectra were experimentally observed due to variation in the Boltzmann factor, and our calculations reproduced it qualitatively. The features that we could not reproduced in the temperature dependence might be attributed to triplet transitions through the spin-orbit interaction effects at present, but further investigations are necessary for conclusive discussions.

Manuscript ID: molecules-selchem-20090108-jp-Shiraiwa
Type of Paper: Review
Title: Selenium Utilization Strategy by Microalgae
Authors: Hiroya Araie and Yoshihiro Shiraiwa
Affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8572 Japan
Abstract: The diversity of selenoproteins raises the question, why do many life forms require selenium? In photosynthetic microorganisms, the essential requirement of selenium was reported by 33 species in 6 phyla. However, the mechanism for the requirement for selenium on biochemical basis is unclear. In organisms of which genome sequences are completely available in database and literatures, 20 species are nominated as selenoprotein-producing organisms and 5 species are photosynthetic organisms. Recently, we studied on selenium utilization and selenoproteins in a coccolithophorid, Emiliania huxleyi (Haptophyta) and found that the algae have unique characteristics. In E. huxleyi, selenite uptake is driven by a high-affinity, active transport system. Then selenite is accumulated as low-molecular-mass compounds that are metabolized to six selenoproteins. The first and second abundant selenoproteins are a protein disulfide isomerase (PDI) homologous protein (EhSEP2) and thioredoxin reductase (TR) 1 (EhSEP1). Involvement of selenium in the molecule is very unique in PDI, but not in TR1. Thus, there are variations in regulation of induction between two selenoproteins in the same organisms. In this review article, we intend to summarize the physiological, biochemical and molecular aspects of selenium utilization by microalgae and try to discuss about the strategy of selenium utilization by microalgae.

Type of Paper: Article
Title: Solid State Polyselenides and Polytellurides: a Huge Variety of Se–Se and Te–Te Interactions
Authors: C. Graf, A. Assoud, M. Oottil, H. Kleinke
Abstract. A huge variety of different interactions between then chalcogen atoms, Q, occur in the solid state structures of polyselenides and polytellurides, including both molecular and infinite units. The simplest motifs are classical Q₂^2– dumbbells and Q_n^2– zigzag chains (n = 3, 4, 5, ..), e.g. found in alkali metal polychalcogenides. In addition, nonclassical so-called hypervalent motifs exist in the form of linear Q₃^4– units or within larger units such as Q₅^4–. Infinite one-dimensional Q units include zigzag, cis/trans and linear chains as well as planar and puckered layers. Several of those are susceptible to Peierls distortions, leading to the formation of both commensurate and incommensurate superstructures and anomalies in transport properties, including metal-nonmetal transitions.