This work studied the influences of formation of BSA/ι-carrageenan complexes on the binding, stability, and antioxidant activity of curcumin. In the presence of BSA and ι-carrageenan, curcumin gives higher intensities of absorption and fluorescence than free curcumin and curcumin only combined with BSA. The added ι-carrageenan is observed to promote curcumin for quenching the instrinsic fluorescence of BSA. These results are explained in terms of the formation of BSA/ι-carrageenan complexes, which help to stabilize the folded structure of BSA for providing curcumin with a more hydrophobic microenvironment. The small difference in anisotropy values of curcumin with BSA alone and of BSA/ι-carrageenan complexes suggests that ι-carrageenan acts as outer stretch conformation in BSA/ι-carrageenan complexes but does not directly disturb the hydrophobic pockets inside BSA, where curcumin is hydrophobically located. The determined values of the binding constant are higher for curcumin with BSA/ι-carrageenan complexes than with BSA alone. Moreover, BSA/ι-carrageenan complexes are found to be superior to single BSA for enhancing the stability and DPPH radical-scavenging ability of curcumin.

Tandem mass spectrum analysis of the enzymatic hydrolysate revealed that the recombinant CSN can cleave linkages of GlcNAcGlcN and GlcN-GlcN in its substrate, suggesting that it is a subclass I chitosanase. In addition, an extensive site-directed mutagenesis study on 10 conserved carboxylic amino acids of glycosyl hydrolase family 75 was performed. This showed that among these various mutants, D160N and E169Q lost nearly all activity. Further investigation using circular dichroism measurements of D160N, E169Q, wild-type CSN, and other active mutants showed similar spectra, indicating that the loss of enzymatic activity in D160N and E169Q was not because of changes in protein structure but was caused by loss of the catalytic essential residue. We conclude that Asp 160 and Glu 169 are the essential residues for the action of A. fumigatus endo-chitosanase.Chitosanase (EC 3.2.1.132) is a hydrolytic enzyme acting on the ␤-1,4-glycosidic linkage of chitosan, a linear biopolymer of ␤-1,4-linked GlcN, to release chito-oligosaccharides. The oligomers GlcNAc and GlcN have interesting biological activities (1), including anti-tumor effects (2, 3), hypo-cholesterolemic effects (4), anti-microbial activities (5, 6), disease-resistance responses, and as phytoalexin elicitors in higher plants (7,8). Hence chitosanase, chito-oligosaccharides and their derivatives have attracted interest from the food and pharmaceutical industries because they can be used as edible additives, agricultural immunity controls and promise many other prospective applications as prophylactic agents for liver diseases (4), atherosclerosis, and hypertension.

The occurrence and transmission of chirality is af ascinating characteristic of nature.H owever,t he intermolecular transmission efficiency of circularly polarized luminescence (CPL) remains challenging due to poor throughspace energy transfer.W er eport au nique CPL transmission from inducing the achiral acceptor to emit CPL within as pecific liquid crystal (LC)-based intermolecular system through ac ircularly polarized fluorescence resonance energy transfer (C-FRET), wherein the luminescent cholesteric LC is employed as the chirality donor,a nd rationally designed achiral long-wavelength aggregation-induced emission (AIE) fluorophore acts as the well-assembled acceptor.Incontrast to photon-release-and-absorption, the chirality transmission channel of C-FRET is highly dependent upon the energy resonance in the highly intrinsic chiral assembly of cholesteric LC,a sv erified by deliberately separating the achiral acceptor from the chiral donor to keep it far beyond the resonance distance.T his C-FRET mode provides ad enovos trategy concept for high-level information processing for applications such as high-density data storage,c ombinatorial logic calculation, and multilevel data encryption and decryption.

Using one ray of light to encode another ray of light is highly desirable because information in optical format can be directly transferred from one beam to another without converting back to the electronic format. One key medium to accomplish such an amazing task is photoswitchable molecules. Using bis(dithiazole)ethene that can be photoswitched between its ring-open and ring-closed states quantitatively with excellent fatigue resistance and high thermal stability, it is shown that quantitative photoreversibility allowed the photoswitching light to control other light travelling through the photoswitchable medium, a phenomenon of transferring information encoded in one light ray to others, thus imparting photo-optical modulation on the orthogonal light beam.

A photochemically active dithiazolethene BN was designed and synthesized, exhibiting a specific gated photochromism. That is, the photochromic reactivity of BN is prevented to a great extent by BF(3), showing a "Lock" gate.