Screening methods for enzyme-mediated alcohol oxidation

Alcohol oxidation for the generation of carbonyl groups, is an essential reaction for the preparation of fine chemicals. Although a number of chemical procedures have been reported, biocatalysis is a promising alternative for more sustainable and selective processes. To speed up the discovery of novel (bio)catalysts for industrial applications, efficient screening approaches need to be established. Here, we report on an enzyme‐mediated alcohol oxidation screening platform to rapidly detect the activities and selectivities of three classes of biocatalysts; ketoreductases (KREDs), alcohol oxidases (AlcOXs) and laccase‐mediator systems (LMSs) with diverse substrates

Application of tethered ruthenium catalysts to asymmetric hydrogenation of ketones, and the selective Hydrogenation of aldehydes

An improved method for the synthesis of tethered ruthenium(II) complexes of monosulfonylated diamines is described, together with their application to the hydrogenation of ketones and aldehydes. The complexes were applied directly, in their chloride form, to asymmetric ketone hydrogenation, to give products in excess of 99% ee in the best cases, using 30 bar of hydrogen at 60 °C, and to the selective reduction of aldehydes over other functional groups

The Christchurch greenbelt - a cultural icon : acknowledging intangible values in resource decision making

The greenbelt policy in Christchurch has recently been the subject of much local publicity. This has been in reaction to development proposals in the greenbelt, and changing regional policies required under the Resource Management Act. This paper is interested in why this issue has generated such concern amongst the local Christchurch community. It traces the greenbelt's historical and cultural origins as a means to understanding its significance. It finds that the greenbelt policy has become a symbol for intangible values about the relationship between the urban and the rural environment. While the term may not be appropriate under the new planning environment, the concept remains an important icon. The challenge for planning is to recognise that such intangible values are not only valid, but significant. Resistance to change will continue until such values are recognised and respected. It is only from here that new, more appropriate concepts may emerge

The Influence of Impeller Geometries on Hemolysis in Bearingless Centrifugal Pumps

Goal: The importance of the main impeller design parameters in bearingless centrifugal pumps with respect to hemolysis for cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) applications are studied in this work. Methods: Impeller prototypes were designed based on theoretical principles. They were manufactured and their hydraulic and hemolytic performance were analyzed experimentally. The cell compatibility is benchmarked against commercially available centrifugal blood pumps BPX-80 (Medtronic) and FloPump 32 (International Biophysics Corporation). Results: The developed prototypes outperform the BPX-80 and FloPump 32 with regard to hemocompatibility by more than a factor of 4.5. The implemented pump features reduced overall and priming volumes. A significant improvement of the cell compatibility is achieved by increasing the radial gap between the impeller and the pump head. The blade should be sufficiently high and a blade outlet angle of 90° provides favorable performance. No correlation between the hydraulic and hemolytic performance is observed. Conclusions: This work identified the most important geometrical parameters of the impeller for blood pumps with respect to cell compatibility. This provides valuable design guidelines for improving existing pumps

A Simple Probe for Super-Resolution Imaging of the Endoplasmic Reticulum in Living Cells

Super-resoln. imaging of living cells can reveal nanoscopic details of live biol. systems. The development of small-mol. fluorophores that allow optimal imaging conditions is the key to enable live-specimen imaging with minimal invasiveness. The authors report a simple and non-toxic rhodamine-based diazoindanone probe compatible with direct stochastic optical reconstruction microscopy (d-STORM). Co-localization studies performed in human cervical cancer (HeLa) cells indicated that this probe targets the endoplasmic reticulum (ER). Photophys. expts. carried out in polyvinyl alc. films revealed that each mol. yields a high no. of photons before photodecompn. (80'000 photons), allowing good localization precision (42 ± 12 nm) in single-mol. localization expts. Super-resoln. imaging employing this photoactivatable probe permitted the visualization of nanoscopic pores within the network of tubules and sheets of the endoplasmic reticulum. The authors further analyzed this structure in three dimensions to distinguish pores from concave surfaces and built 3D reconstructions of these nanometric tubules and cisternae

Towards the enzymatic synthesis of phosphorothioate containing LNA oligonucleotides

International audienceTherapeutic oligonucleotides require the addition of multiple chemical modifications to the nucleosidic scaffold in order to improve their drug delivery efficiency, cell penetration capacity, biological stability, and pharmacokinetic properties. This chemical modification pattern is often accompanied by a synthetic burden and by limitations in sequence length. Here, we have synthesized a nucleoside triphosphate analog bearing two simultaneous modifications at the level of the sugar (LNA) and the backbone (thiophosphate) and have tested its compatibility with enzymatic DNA synthesis which could abrogate some of these synthetic limitations. While this novel analog is not as well tolerated by polymerases compared to the corresponding α-thio-dTTP or LNA-TTP, α -thio-LNA-TTP can readily be used for enzymatic synthesis on universal templates for the introduction of phosphorothioated LNA nucleotides