Structural characterization of ether lipids from the archaeon Sulfolobus islandicus by high‐resolution shotgun lipidomics

The molecular structures, biosynthetic pathways and physiological functions of membrane lipids produced by organisms in the domain Archaea are poorly characterized as compared with that of counterparts in Bacteria and Eukaryota. Here we report on the use of high‐resolution shotgun lipidomics to characterize, for the first time, the lipid complement of the archaeon Sulfolobus islandicus. To support the identification of lipids in S. islandicus, we first compiled a database of ether lipid species previously ascribed to Archaea. Next, we analyzed the lipid complement of S. islandicus by high‐resolution Fourier transform mass spectrometry using an ion trap‐orbitrap mass spectrometer. This analysis identified five clusters of molecular ions that matched ether lipids in the database with sub‐ppm mass accuracy. To structurally characterize and validate the identities of the potential lipid species, we performed structural analysis using multistage activation on the ion trap‐orbitrap instrument as well as tandem mass analysis using a quadrupole time‐of‐flight machine. Our analysis identified four ether lipid species previously reported in Archaea, and one ether lipid species that had not been described before. This uncharacterized lipid species features two head group structures composed of a trisaccharide residue carrying an uncommon sulfono group (?SO₃) and an inositol phosphate group. Both head groups are linked to a glycerol dialkyl glycerol tetraether core structure having isoprenoid chains with a total of 80 carbon atoms and 4 cyclopentane moieties. The shotgun lipidomics approach deployed here defines a novel workflow for exploratory lipid profiling of Archaea. Copyright © 2015 John Wiley & Sons, Ltd.     

DNA‐Based Oligochromophores as Light‐Harvesting Systems

The chromophores ethynyl pyrene as blue, ethynyl perylene as green and ethynyl Nile red as red emitter were conjugated to the 5‐position of 2′‐deoxyuridine via an acetylene bridge. Using phosphoramidite chemistry on solid phase labelled DNA duplexes were prepared that bear single chromophore modifications, and binary and ternary combinations of these chromophore modifications. The steady‐state and time‐resolved fluorescence spectra of all three chromophores were studied in these modified DNA duplexes. An energy‐transfer cascade occurs from ethynyl pyrene over ethynyl perylene to ethynyl Nile red and subsequently an electron‐transfer cascade in the opposite direction (from ethynyl Nile red to ethynyl perylene or ethynyl pyrene, but not from ethynyl perylene to ethynyl pyrene). The electron‐transfer processes finally provide charge separation. The efficiencies by these energy and electron‐transfer processes can be tuned by the distances between the chromophores and the sequences. Most importantly, excitation at any wavelength between 350 and 700 nm finally leads to charge separated states which make these DNA samples promising candidates for light‐harvesting systems.     

Heavy ion induced desorption (HIID) mass spectrometry of Langmuir-Blodgett films built from CD-salts of fatty acids

Langmuir-Blodgett films made from cadmium salts of fatty acids have been analyzed by means of the heavy ion induced mass spectrometry in which megaelectronvolt ions are used to desorb sample specific molecules. The method is a useful tool for detecting incomplete salt formation at the subphase and the replacement of the original counter-ion by ions from the substrate surface. The method exhibits a depth sensitivity which can be varied between 2 to 14 layers depending on the energy loss of the heavy ion.     

Groups whose subgroups have small automizers

IfH is a subgroup of a groupG, theautomizer ofH inG is the group of all automorphisms ofH induced by elements of its normalizerN _G (H). the subgroupH is said to havesmall automizer ifAut _G (H)=Inn(H), i.e. ifN _G (H)=HC _G (H). This article is devoted to the study of groups for which many subgroups have small automizer. In Memoriam Valeria Fedri R. Brandl wishes to express his sincerest thanks for the warm hospitality offered by the Department of Mathematics of the University of Napoli “Federico II” for the time of writing this paper.     

Integer Polynomials with Roots mod p for all Primes p

Let f(X) be an integer polynomial which is a product of two irreducible factors. Assume that f(X) has a root mod p for all primes p. If the splitting field of f(X) over the rationals is a cyclic extension of the stem fields, then the Galois group of f(X) over the rationals is soluble and of bounded Fitting length. Moreover, the fixed groups of the stem extensions are in, some sense, unique.     

Interfaces for data processing in surface analysis

As computer controlled instruments for surface analysis are in common use for many years, the problem of exchangeability of analytical data has attracted interest in the surface analysis community. More and more examples for the development of standarized data formats as the VAMAS format [1] and the Standard for Chromatography Data Communication from the AIA [2] have been published. There are a few attempts to establish standardized “data dictionaries” e.g. the parameter lists describing AES and XPS spectra pusblished in Surface Science Spectra [3, 4]. If several different analysis methods (such as AES, SAM, XPS, SIMS, STM, AFM, EPMA, …) are applied to the same sample, a quite independent and open approach is needed to be able to combine data of various instruments in a common data evaluation procedure. It could be the basic concept of real mutli-method analysis. The public domain software package MAXMIND has been developed, as only a standardized data exchange and storage format based on data dictionaries can guarantee a high level of independence of proprietary measurement systems. Received: 16 January 1997 / Revised: 9 May 1997 / Accepted: 14 May 1997