Beyond the Diffusion Limit: Pre-Associated Ion-Pair Photoinitiating Systems for Radical Photopolymerization.

The pre-association mechanism of an ion-pair Type II photoinitiating system (PIS) acting in the visible range was studied. The choice of a dye as photoinitiator (crystal violet) with an excited state lifetime of 200 ps ensured the absence of dynamical quenching by the borate salts used as coinitiator. In spite of the fact that no diffusional bimolecular quenching can take place, excellent polymerization efficiency was found, underlining the high reactivity of the PIS.

Asymmetric Total Synthesis and Structural Revision of DAT, an Antigenic Glycolipid from Mycobacterium tuberculosis.

DAT is a member of the diacyl trehalose family (DAT) of antigenic glycolipids located in the mycomembrane of Mycobacterium tuberculosis (Mtb). Recently it was shown that the molecular structure of DAT had been incorrectly assigned, but the correct structure remained elusive. Herein, the correct molecular structure of DAT and its methyl-branched acyl substituent mycolipanolic acid is determined.

Total Syntheses of Nominal and Actual Prorocentin.

The dinoflagellate-derived polyether prorocentin is a co-metabolite of the archetypical serine/threonine phosphatase inhibitor okadaic acid. Whereas a structural relationship cannot be missed and a biosynthetic link was proposed, it is currently unknown whether there is any parallel in the bioactivity profile of these natural products. However, it was insinuated in the past that the structure assigned to prorocentin might need to be revised.

Directing Coupled Motion with Light: A Key Step Toward Machine-Like Function.

Molecular photoactuators can control shape and chemical or physical properties of the responsive system they are embedded in. These effects are usually mediated by supramolecular interactions and can be amplified to perform work at the micro- and macroscopic scale, for instance, in materials and biomimetic systems. While many studies focus on the observable outcome of these events, photoresponsive structures can also translate their conformational change to molecular components and perform work against random Brownian motion.

Chemical Synthesis of Cell Wall Constituents of .

The pathogen (), causing tuberculosis disease, features an extraordinary thick cell envelope, rich in specific lipids, glycolipids, and glycans. These cell wall components are often directly involved in host-pathogen interaction and recognition, intracellular survival, and virulence. For decades, these mycobacterial natural products have been of great interest for immunology and synthetic chemistry alike, due to their complex molecular structure and the biological functions arising from it.

Total Synthesis of the Alleged Structure of Crenarchaeol Enables Structure Revision*.

Crenarchaeol is a glycerol dialkyl glycerol tetraether lipid produced exclusively in Archaea of the phylum Thaumarchaeota. This membrane-spanning lipid is undoubtedly the structurally most sophisticated of all known archaeal lipids and an iconic molecule in organic geochemistry. The 66-membered macrocycle possesses a unique chemical structure featuring 22 mostly remote stereocenters, and a cyclohexane ring connected by a single bond to a cyclopentane ring.

Synthetic mycobacterial diacyl trehaloses reveal differential recognition by human T cell receptors and the C-type lectin Mincle.

The cell wall of Mycobacterium tuberculosis is composed of diverse glycolipids which potentially interact with the human immune system. To overcome difficulties in obtaining pure compounds from bacterial extracts, we recently synthesized three forms of mycobacterial diacyltrehalose (DAT) that differ in their fatty acid composition, DAT, DAT, and DAT. To study the potential recognition of DATs by human T cells, we treated the lipid-binding antigen presenting molecule CD1b with synthetic DATs and looked for T cells that bound the complex.

Asymmetric Total Synthesis of Mycobacterial Diacyl Trehaloses Demonstrates a Role for Lipid Structure in Immunogenicity.

The first asymmetric total synthesis of three structures proposed for mycobacterial diacyl trehaloses, DAT, DAT, and DAT is reported. The presence of two of these glycolipids, DAT and DAT, within different strains of pathogenic M. tuberculosis was confirmed, and it was shown that their abundance varies significantly.

A T-cell receptor escape channel allows broad T-cell response to CD1b and membrane phospholipids.

CD1 proteins are expressed on dendritic cells, where they display lipid antigens to T-cell receptors (TCRs). Here we describe T-cell autoreactivity towards ubiquitous human membrane phospholipids presented by CD1b. These T-cells discriminate between two major types of lipids, sphingolipids and phospholipids, but were broadly cross-reactive towards diverse phospholipids including phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine.

Mass spectrometry-based ligand binding assays on adenosine A1 and A2A receptors.

Conventional methods to measure ligand-receptor binding parameters typically require radiolabeled ligands as probes. Despite the robustness of radioligand binding assays, they carry inherent disadvantages in terms of safety precautions, expensive synthesis, special lab requirements, and waste disposal. Mass spectrometry (MS) is a method that can selectively detect ligands without the need of a label.

Dispositional factors, coping and adaptation during menopause.

The objective of the study was to examine the direct and indirect influences of dispositional factors, namely optimism, health-related hardiness (HRH) and sense of coherence (SOC), on the symptom experiences of peri- and postmenopausal women. Indirect effects of dispositional factors were examined via attitudes to the menopause and coping (emotion-versus problem-focused). A survey methodology was employed to assess the research objective for 176 peri- and postmenopausal women recruited from menopause clinics and family planning centers in Queensland, Australia.