Facile biosynthesis of synthetic crystalline cellulose nanoribbon from maltodextrin through a minimized two-enzyme phosphorylase cascade and its application in emulsion.

Nanocellulose has many promising applications such as a green ingredient for Pickering emulsion. Traditional strategies to produce nanocellulose, which are acid or enzymatic hydrolysis and mechanical methods on natural complicated cellulose, are hard to control and can result in significant pollutants during the processes. Herein, we demonstrated a facile and sustainable method for the biocatalytic production of insoluble synthetic crystalline cellulose nanoribbon (CCNR) from cheap maltodextrin by coupling α-glucan phosphorylase (αGP) and cellodextrin phosphorylase (CDP) using cellobiose as a primer. And by optimizing the combination of different αGP and CDP, it turned out that the optimal enzyme combination is αGP from Thermotoga maritime and CDP from Clostridium thermocellum, in which CDP was attached to a family 9 cellulose-binding module. The product yield and degree of polymerization (DP) of insoluble synthetic CCNR was affected by the primer concentration at a fixed concentration of maltodextrin. After optimization of reaction conditions, the highest product yield of insoluble synthetic CCNR was 44.92 % and the highest DP of the insoluble synthetic CCNR was 24 from 50 g 1-1 maltodextrin. This insoluble synthetic CCNR can be used as a Pickering emulsions stabilizer, showing excellent emulsifiability. This study provides a promising alternative for cost-efficient production of insoluble synthetic CCNR which was used as a green emulsion stabilizer.

CB1-Antibody Modified Liposomes for Targeted Modulation of Epileptiform Activities Synchronously Detected by Microelectrode Arrays.

Temporal lobe epilepsy (TLE) is a focal, recurrent, and refractory neurological disorder. Therefore, precisely targeted treatments for TLE are greatly needed. We designed anti-CB1 liposomes that can bind to CB1 receptors in the hippocampus to deliver photocaged compounds (ruthenium bipyridine triphenylphosphine γ-aminobutyric acid, RuBi-GABA) in the TLE rats. A 16-channel silicon microelectrode array (MEA) was implanted for simultaneously monitoring electrophysiological signals of neurons. The results showed that anti-CB1 liposomes were larger in size and remained in the hippocampus longer than unmodified liposomes. Following the blue light stimulation, the neural firing rates and the local field potentials of hippocampal neurons were significantly reduced. It is indicated that RuBi-GABA was enriched near hippocampal neurons due to anti-CB1 liposome delivery and photolyzed by optical stimulation, resulting dissociation of GABA to exert inhibitory actions. Furthermore, K-means cluster analysis revealed that the firing rates of interneurons were decreased to a greater extent than those of pyramidal neurons, which may have been a result of the uneven diffusion of RuBi-GABA due to liposomes binding to CB1. In this study, we developed a novel, targeted method to regulate neural electrophysiology in the hippocampus of the TLE rat using antibody-modified nanoliposomes, implantable MEA, and photocaged compounds. This method effectively suppressed hippocampal activities during seizure ictus with high spatiotemporal resolution, which is a crucial exploration of targeted therapy for epilepsy.

Depiction of carbohydrate-active enzyme diversity in Caldicellulosiruptor sp. F32 at the genome level reveals insights into distinct polysaccharide degradation features.

Thermophilic bacterium Caldicellulosiruptor sp. F32 can utilize cellulose-, hemicellulose-containing biomass, including unpretreated wheat straw. We have conducted a bioinformatics analysis of the carbohydrate-active enzyme (CAZyme) in the genome of Caldicellulosiruptor sp. F32, which reveals a broad substrate range of the strain. Among 2285 predicted open reading frames (ORFs), 73 (3.2%) CAZyme encoding genes, including 44 glycoside hydrolases (GHs) distributing in 22 GH families, 6 carbohydrate esterases (CEs), 3 polysaccharide lyases (PLs), 21 glycosyl transferases (GTs), and 25 carbohydrate-binding modules (CBMs) were found. An in-depth bioinformatics analysis of CAZyme families that target cellulose, hemicellulose, chitin, pectin, starch, and ß-1,3-1,4-glucan degradation were performed to highlight specialized polysaccharide degrading abilities of strain F32. A great number of orthologous multimodular CAZymes of Caldicellulosiruptor sp. F32 were found in other strains of genus Caldicellulosiruptor. While, a portion of the CAZymes of Caldicellulosiruptor sp. F32 showed sequence identity with proteins from strains of genus Clostridium. A thermostable ß-glucosidase BlgA synergistically facilitated the enzymatic degradation of Avicel by endo-1,4-ß-glucanase CelB, which indicated that the synchronous action of synergism between CAZymes enhanced the lignocellulose degradation by Caldicellulosiruptor sp. F32.