Total Synthesis of the Indole Alkaloids Raputindol A and Raputimonoindole A-F

Eine Vielzahl von Indolalkaloiden wurde seit 2010 aus Raputia simulans und R. praetermissa (Rutaceae) isoliert. Alle besitzen eine unsubstituierte Enaminstruktur des Indols, eine Eigenschaft die nur selten bei anderen Naturstoffen zu finden ist. Das terpenoide, dimere Bisindolalkaloid Raputindol A besitzt eine lineare Cyclopenta[f]indol-Teilstruktur, wohingegen die Raputimonoindole A-F eine Furaneinheit unterschiedlicher Oxidationsstufen an der Indol-5-Position aufweisen. In dieser Arbeit wird die erste Totalsynthese dieser Naturstoffe berichtet und absolute Konfigurationen zugewiesen. Die Cyclopenta[f]indol-Teilstruktur des Raputindol A wurde durch regioselektive Gold(I)-katalysierte Cycloisomerisierung von Propargylacetaten zugänglich. Chirale Liganden oder Chiralitätstransfer erlaubten keine enantioselektive Synthese. Die Einführung einer Isobutenyl-Seitenkette schlug unter diversen Bedingungen fehl. Sie konnte schließlich durch eine Suzuki-Miyaura Kreuzkupplung installiert werden. Die regioselektive Reduktion des erhaltenen 1,3-Diens wurde durch LiDBB erreicht. Die Methode ließ sich nicht für eine diastereoselektive Synthese modifizieren. Der zweite Indolkern wurde über eine Heck-Kupplung eingeführt, was in 6.6% Ausbeute über 9 Stufen zu synthetischem Raputindol A führte. Die Enantiomere wurden per HPLC an chiraler Phase getrennt und ihre ECD-Spektren gemessen. Ein simuliertes ECD-Spektrum aus TD-DFT Rechnungen bestätigte die (R,R)-Konfiguration des Naturstoffs. Eine zweite, diastereoselektive Synthese von Raputindol A, mit einer OH-dirigierten Hydrierung als Schlüsselschritt, wurde entwickelt. Die regio- und diastereoselektive Hydrierung eines 1,3-Diens wurde durch den Crabtree-Katalysator erreicht. Die Wittig-Olefinierung eines alpha-quartären Aldehyds führte zu einer noch nie berichteten Eliminierung von Formaldehyd. Die Synthese von Raputindol A wurde mit einer verbesserten Ausbeute von 18% über 13 Stufen durch Takai-Olefinierung und Suzuki-Miyaura Kreuzkupplung abgeschlossen. Raputimonoindol B wurde durch Ir-katalysierte Borylierung und Suzuki-Miyaura Kreuzkupplung synthetisiert. Durch einfache Transformationen wurden die Raputimonoindole C und D aus Raputimonoindol B erhalten. Aus enantiomerenreinen 5-(1-Hydroxyallyl)-indolen konnten die Raputimonoindole A, E und F aufgebaut werden. Eine diastereoselektive Domino Heck-Suzuki Reaktion ergab Raputimonoindol A, wohingegen eine Ringschlussmetathese zu den Raputimonoindolen E und F führte.A variety of indole alkaloids have been isolated from Raputia simulans und R. praetermissa (Rutaceae) since 2010. All of them possess an unsubstituted enamine section of the indole core, a trait rarely found in other natural products. The terpenoid, dimeric bisindole alkaloid raputindole A exhibits a linear cyclopenta[f]indole partial structure, whereas the raputimonoindoles A-F feature differently oxidized furan moieties at the indole-5-position. In this work, the first total synthesis for each of these natural products is reported and absolute configurations are assigned. The cyclopenta[f]indole structure of raputindole A was accessed by a regioselective, Gold(I)-catalyzed cycloisomerization of propargylic acetates. Chiral ligands or chirality transfer did not allow for an enantioselective synthesis. The introduction of an isobutenyl side chain failed under various conditions. Finally, Suzuki-Miyaura cross coupling allowed for its installation. The challenging regioselective reduction of the obtained 1,3-diene was achieved by the use of LiDBB. Unfortunately, this method could not be modified towards diastereoselectivity. Introduction of the second indole moiety via Heck coupling gave access to synthetic raputindole A for the first time in 6.6% yield over 9 steps. The enantiomers were separated by chiral phase HPLC and their ECD spectra were recorded. A simulated ECD spectrum from TD-DFT calculations revealed the natural products absolute configuration to be (R,R). A second generation, diastereoselective synthesis of raputindole A was developed featuring an OH-directed hydrogenation as key step. The regio- and diastereoselective hydrogenation of a 1,3-diene was achieved by the use of Crabtree’s catalyst. Wittig-type olefination of an alpha-quaternary aldehyde revealed an unprecedented elimination of formaldehyde. Finally, the synthesis was completed by Takai-Olefination and Suzuki-Miyaura cross coupling, giving raputindole A in an improved yield of 18% over 13 steps. Raputimonoindole B was synthesized in one step via Ir-catalyzed borylation and subsequent Suzuki-Miyaura cross coupling. By simple transformations, raputimonoindoles C and D can be reached from raputimonoindole B. From enantiopure 5-(1-hydroxyallyl)-indoles raputimonoindoles A, E and F can be build up. A diastereoselective domino Heck-Suzuki reaction efficiently led to raputimonoindole A, whereas alkene ring-closing metathesis gave access to raputimonoindole E and F

Immunoadsorption for Treatment of Patients with Suspected Alzheimer Dementia and Agonistic Autoantibodies against Alpha1a-Adrenoceptor—Rationale and Design of the IMAD Pilot Study

Background: agonistic autoantibodies (agAABs) against G protein-coupled receptors (GPCR) have been linked to cardiovascular disease. In dementia patients, GPCR-agAABs against the α1- and ß2-adrenoceptors (α1AR- and ß2AR) were found at a prevalence of 50%. Elimination of agAABs by immunoadsorption (IA) was successfully applied in cardiovascular disease. The IMAD trial (Efficacy of immunoadsorption for treatment of persons with Alzheimer dementia and agonistic autoantibodies against alpha1A-adrenoceptor) investigates whether the removal of α1AR-AABs by a 5-day IA procedure has a positive effect (improvement or non-deterioration) on changes of hemodynamic, cognitive, vascular and metabolic parameters in patients with suspected Alzheimer’s clinical syndrome within a one-year follow-up period. Methods: the IMAD trial is designed as an exploratory monocentric interventional trial corresponding to a proof-of-concept phase-IIa study. If cognition capacity of eligible patients scores 19–26 in the Mini Mental State Examination (MMSE), patients are tested for the presence of agAABs by an enzyme-linked immunosorbent assay (ELISA)-based method, followed by a bioassay-based confirmation test, further screening and treatment with IA and intravenous immunoglobulin G (IgG) replacement. We aim to include 15 patients with IA/IgG and to complete follow-up data from at least 12 patients. The primary outcome parameter of the study is uncorrected mean cerebral perfusion measured in mL/min/100 gr of brain tissue determined by magnetic resonance imaging with arterial spin labeling after 12 months. Conclusion: IMAD is an important pilot study that will analyze whether the removal of α1AR-agAABs by immunoadsorption in α1AR-agAAB-positive patients with suspected Alzheimer’s clinical syndrome may slow the progression of dementia and/or may improve vascular functional parameters

Structural and Functional Characterization of PA14/Flo5-Like Adhesins From Komagataella pastoris

Cell–cell and cell-substrate based adhesion of yeasts are major determinants of their adoption of different life styles. Genome-mining of ascomycetous GPI-anchored cell wall proteins with lectin-like PA14 domains identified a unique class of putative adhesins in the clade of methylotrophic Komagataella yeasts, many of which are known to colonize plants and insects involving yet unknown adhesion mechanisms. Here, we report the functional and structural analysis of two of its members: KpFlo1 (=Cea1), that is highly specific for terminal N-acetylglucosamine moieties, and KpFlo2, which represents an orphan lectin with intact binding site but unknown specificity. Crystal structures of the Cea1 adhesion domain complexed to N-acetylglucosamine and N,N′-diacetylchitobiose reveal a Ca2+-dependent binding mode that differs from other members of the PA14/Flo5 adhesin family. Heterologous expression of Cea1A in Saccharomyces cerevisiae promotes cellular adhesion to non-reducing ends of non-crystalline chitin. Overall, our data suggest that high-affinity recognition of β-GlcNAc-capped glycans by Cea1 enable Komagataella species to interact with surface cues present in fungi and insects

Infection prevention and control interventions in the first outbreak of methicillin-resistant Staphylococcus aureus infections in an equine hospital in Sweden

<p>Abstract</p> <p>Background</p> <p>The first outbreak of methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) infection in horses in Sweden occurred in 2008 at the University Animal Hospital and highlighted the need for improved infection prevention and control. The present study describes interventions and infection prevention control in an equine hospital setting July 2008 - April 2010.</p> <p>Method</p> <p>This descriptive study of interventions is based on examination of policy documents, medical records, notes from meetings and cost estimates. MRSA cases were identified through clinical sampling and telephone enquiries about horses post-surgery. Prospective sampling in the hospital environment with culture for MRSA and genotyping of isolates by <it>spa</it>-typing and pulsed-field gel electrophoresis (PFGE) were performed.</p> <p>Results</p> <p>Interventions focused on interruption of indirect contact spread of MRSA between horses via staff and equipment and included: Temporary suspension of elective surgery; and identification and isolation of MRSA-infected horses; collaboration was initiated between authorities in animal and human public health, human medicine infection control and the veterinary hospital; extensive cleaning and disinfection was performed; basic hygiene and cleaning policies, staff training, equipment modification and interior renovation were implemented over seven months.</p> <p>Ten (11%) of 92 surfaces sampled between July 2008 and April 2010 tested positive for MRSA <it>spa</it>-type 011, seven of which were from the first of nine sampling occasions. PFGE typing showed the isolates to be the outbreak strain (9 of 10) or a closely related strain. Two new cases of MRSA infection occurred 14 and 19 months later, but had no proven connections to the outbreak cases.</p> <p>Conclusions</p> <p>Collaboration between relevant authorities and the veterinary hospital and formation of an infection control committee with an executive working group were required to move the intervention process forward. Support from hospital management and the dedication of staff were essential for the development and implementation of new, improved routines. Demonstration of the outbreak strain in the environment was useful for interventions such as improvement of cleaning routines and interior design, and increased compliance with basic hygienic precautions. The interventions led to a reduction in MRSA-positive samples and the outbreak was considered curbed as no new cases occurred for over a year.</p

26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)