Controllable enzymatic hydrolysis in reverse Janus emulsion microreactors.

HYPOTHESIS: The key feature of living cells is multicompartmentalization for enzymatic reactions. Artificial cell-like multicompartments with micro domains are appealing to mimic the biological counterparts. In addition, establishing a sustainable, efficient, and controllable reaction system for enzymatic hydrolysis is imperative for the production of natural fatty acids from animal and plant-based fats. EXPERIMENTS: Reverse Janus emulsion microreactors, i.e. (W1 + W2)/O, is constructed through directly using natural fats as continuous phase and aqueous two-phase solutions (ATPS) as inner phases. Enzyme is confined in the compartmented aqueous droplets dominated by the salt of Na2SO4 and polyethylene glycol (PEG). Enzyme catalyzed ester hydrolysis employed as a model reaction is performed under the conditions of agitation-free and mild temperature. Regulation of reaction kinetics is investigated by diverse droplet topology, composition of inner ATPS, and on-demand emulsification. FINDINGS: Excellent enzymatic activity toward hydrolysis of plant and animal oils achieves 88.5 % conversion after 3 h. Compartmented micro domains contribute to condense and organize the enzymes spatially. Timely removal of the products away from reaction sites of oil/water interface "pushed" the reaction forward. Distribution and transfer of enzyme in two aqueous lobes provide extra freedom in the regulation of hydrolysis kinetics, with equilibrium conversion controlled freely from 14.5 % to 88.5 %. Reversible "open" and "shut" of hydrolysis is acheived by on-demand emulsification and spontaneous demulsification. This paper paves the way to advancing progress in compartmentalized emulsion as a sustainable and high-efficiency platform for biocatalytic applications.

Construction and regulation of aqueous-based Cerberus droplets by vortex mixing.

HYPOTHESIS: The emerging aqueous-based Cerberus emulsion droplets with multi-domains behave as an excellent platform to design cyto-mimetic compartmentalization for fabrication of anisotropic biomimetic materials and microreactors. However, the ultralow water/water interfacial tension impedes fabrication of aqueous Cerberus droplets in batch-scale and precisely topology regulation especially under lack of deep understanding of w/w interface properties. EXPERIMENTS: Aqueous-based ternary phase diagram composed by salt, hydrophilic polymer and fluorocarbon compound is determined. Different emulsions employing the multiple aqueous solutions as internal phase and vegetable oil as continuous phase, are prepared by traditional vortex mixing based on the diagram. The construction mechanism of (W1 + W2 + W3)/O Cerberus droplets and relationship between droplet topology and the diagram are investigated. FINDINGS: Diverse categories of aqueous-based emulsions from single emulsions, Janus emulsions, to Cerberus emulsions are delicately controlled in the same system based on the diagram. Various morphologies of Cerberus droplets such as linear and fan-like configurations are obtained, although spreading coefficient based on interfacial tension indicates preference of onion-like configuration. The viscosity plays an unexpected role in the construction of Cerberus droplets due to highly sensitive water/water interfaces within the droplets. Moreover, an empirical equation is perfectly applied, which endows quantitative prediction and control of lobe volume ratio within Cerberus droplets.

[Congenital dyserythropoietic anemia type II with novel mutations in SEC23B and HFE2 genes: a Chinese family survey].

OBJECTIVE: To report novel mutations SEC23B gene in congenital dyserythropoietic anemia (CDA). METHODS: By direct sequencing method, we sequenced CDAN1 and SEC23B genes in a Chinese CDA II patient, presented with chronic fatigue and dark urine, as well as his family members. Serum hepcidin was assayed by mass spectrometry. RESULTS: We found a c.71G>A mutation and a c.74C> A mutation in the patient. In addition, a heterozygous c.55A>G mutation of HFE2 gene was found in some family members. The level of serum hepcidin of the patient was below the detection limit (<1 nmol/L). CONCLUSION: Contrary with what have been reported previously in the Europe, especially in the Italy, the gene mutations identified in this case was different and novel. The two novel mutations contribute to the diagnosis of CDAII and are the first report in East Asian CDAII patients.