Solid-state NMR studies of mechanism of the opsin shift in the visual pigment rhodopsin

Bio-organic SynthesisSolid state NMR/Biophysical Organic Chemistr

An automated Raman-based platform for the sorting of live cells by functional properties

Stable-isotope probing is widely used to study the function of microbial taxa in their natural environment, but sorting of isotopically labelled microbial cells from complex samples for subsequent genomic analysis or cultivation is still in its early infancy. Here, we introduce an optofluidic platform for automated sorting of stable-isotope-probing-labelled microbial cells, combining microfluidics, optical tweezing and Raman microspectroscopy, which yields live cells suitable for subsequent single-cell genomics, mini-metagenomics or cultivation. We describe the design and optimization of this Raman-activated cell-sorting approach, illustrate its operation with four model bacteria (two intestinal, one soil and one marine) and demonstrate its high sorting accuracy (98.3 ± 1.7%), throughput (200-500 cells h-1; 3.3-8.3 cells min-1) and compatibility with cultivation. Application of this sorting approach for the metagenomic characterization of bacteria involved in mucin degradation in the mouse colon revealed a diverse consortium of bacteria, including several members of the underexplored family Muribaculaceae, highlighting both the complexity of this niche and the potential of Raman-activated cell sorting for identifying key players in targeted processes.</p

Toekomstdenken in het aardrijkskundeonderwijs

Onderwijs moet jonge mensen voorbereiden op de toekomst. Daar is iedereen het over eens. Maar nadenken over mogelijke en wenselijke toekomsten gebeurt zelden op school. Hoe kunnen we in het aardrijkskundeonderwijs op een zinvolle manier jongeren over ‘toekomsten’ laten nadenken

Toekomstdenken in het aardrijkskundeonderwijs

Onderwijs moet jonge mensen voorbereiden op de toekomst. Daar is iedereen het over eens. Maar nadenken over mogelijke en wenselijke toekomsten gebeurt zelden op school. Hoe kunnen we in het aardrijkskundeonderwijs op een zinvolle manier jongeren over ‘toekomsten’ laten nadenken

Density Functional Theory Study of the Structure and 13C Chemical Shifts of Retinylidene Iminium Salts

We present a density functional theory calculation of the structure and C-13 chemical shifts of retinylidene molecules which constitute the chromophores of the natural pigments rhodopsin and bacteriorhodopsin. We compare our results with recent X-ray and NMR spectroscopic data on several retinylidene iminium salts characterized by different cation-anion interactions. In agreement with crystallographic data, we find that the amplitude of the bond length alternation between single and double carbon bonds is strongly reduced in the vicinity of the protonated Schiff base nitrogen. The chemical shifts along the carbon chain are in very good agreement with the experimental values for the neutral retinylidene compounds and in fairly good agreement for the charged retinylidene compounds. We find that the C-13 chemical shift is mostly affected by the cation-anion distance and to a lesser extent by the presence of hydrogen bonding interaction between the protonated Schiff base of retinal and the counterion. The correlation between C-13 chemical shift and atomic charge along the conjugated chain of retinals is found to depend strongly on the specific compound. This result suggests some caution in using atomic charges alone to establish the position of the counterion relative to the chromophore in rhodopsin