Highly regioselective surface acetylation of cellulose and shaped cellulose constructs in the gas-phase

Gas-phase acylation of cellulose is an attractive method for modifying the surface properties of cellulosics. However, little is known concerning the regioselectivity of the chemistry, in terms of which cellulose positions are preferentially acylated and if acylation can be restricted to the surface, preserving crystallinities/morphologies. Consequently, we reexplore simple gas-phase acetylation of modern-day cellulosic building blocks – cellulose nanocrystals, pulps, regenerated fibre and aerogels. The gas-phase acetylation is shown to be highly regioselective for the C6-OH, is further supported with computational modelling. This contrasts with liquid-state acetylation, highlighting that the gas-phase chemistry is much more controllable, yet with similar kinetics to the uncatalyzed liquid-phase reactions. Furthermore, this method preserves both the native crystalline structure of cellulose and the supramolecular morphologies of even delicate cellulosic constructs (aerogel exhibiting retention of chiral cholesteric liquid crystalline phases). Therefore, we are convinced that this methodology will lead to more rapid adoption of precisely tailored and cellulosic materials

Photo-controllable rotational motion of cholesteric liquid crystalline droplets in a dispersion system

A photo-controllable rotational motion was demonstrated for an isolated cholesteric liquid crystalline droplet in a surfactant solution.

The Biochemistry and Evolution of the Dinoflagellate Nucleus

Dinoflagellates are known to possess a highly aberrant nucleus—the so-called dinokaryon—that exhibits a multitude of exceptional biological features. These include: (1) Permanently condensed chromosomes; (2) DNA in a cholesteric liquid crystalline state, (3) extremely large DNA content (up to 200 pg); and, perhaps most strikingly, (4) a deficit of histones—the canonical building blocks of all eukaryotic chromatin. Dinoflagellates belong to the Alveolata clade (dinoflagellates, apicomplexans, and ciliates) and, therefore, the biological oddities observed in dinoflagellate nuclei are derived character states. Understanding the sequence of changes that led to the dinokaryon has been difficult in the past with poor resolution of dinoflagellate phylogeny. Moreover, lack of knowledge of their molecular composition has constrained our understanding of the molecular properties of these derived nuclei. However, recent advances in the resolution of the phylogeny of dinoflagellates, particularly of the early branching taxa; the realization that divergent histone genes are present; and the discovery of dinoflagellate-specific nuclear proteins that were acquired early in dinoflagellate evolution have all thrown new light nature and evolution of the dinokaryon.