Characterization of an extreme alkaline-stable keratinase from the draft genome of feather-degrading Bacillus sp.JM7 from deep-sea

Bacillus sp. JM7, a strain isolated from the deep-sea of the South China Sea, was found to efficiently degrade 79.4% native chicken feather within 30 h. Scanning electron microscopy analysis showed that JM7 strain could gradually degrade feather by modifying the microstructure of feather keratin. A total of 25 protease genes were predicted from the draft genome of JM7 strain, among which a predicted subtilisin-like serine protease(designated as Ker02562) was further characterized for its keratinolytic activity. The recombinant Ker02562 functioned at a wide range of temperatures from 30℃ to 60℃, with an optimum at 40–50℃. Ker02562 was highly active at various pHs ranging from 5.0 to 13.0, with a maximum activity observed at pH 7.0–9.0. Remarkably, recombinant Ker02562 was stable in extreme alkaline environments(pH 10–13), which was much better than most other reported keratinases. Collectively, these favorable properties could make Bacillus sp. JM7 and Ker02562 attractive to be applied in the detergent formulation and feather bioconversion.

Emergency material scheduling optimization model and algorithms:A review

In the emergency management of disruptions,efficient emergency material scheduling(EMS) is a key factor to save people’s lives and reduce loss.Based on the literature of EMS and related areas in recent years,the research was summarized from two aspects of EMS optimization model and algorithms.It is concluded that the EMS optimization models mainly aim at the shortest time,shortest distance,minimum cost,maximum satisfaction and fairness,etc.The constraints usually include the quantity of supply depots,relief supply and vehicles,the types of commodities,the road network conditions,the budgets and the demand forecast of emergency materials.Multi-objective model is more complex and it usually considers more than one objective.To find the optimized solution,the multiobjective model with complex constraints needs more efficient algorithms.The existing algorithms,including mathematic algorithm and heuristic algorithm,have been categorized.For NP-hard(non-deterministic polynomial hard) problems,heuristic algorithms should be designed,which mainly include genetic algorithm(GA),ant colony optimization(ACO),particle swarm optimization(PSO),etc.Based on the characteristics of the optimization model and various algorithms,appropriate algorithm or tools should be chosen and designed to obtain the optimized solution of EMS model.Finally,the development trends of EMS optimization model and algorithm in the future are proposed.

Emission-Tunable Nanofluorophores through Self-assembly of Amphiphilic Block Copolymers:toward Application in Cell Imaging

Comprehensive Summary Nanofluorophores based on aggregation-induced emission(AIE)dyes have recently received considerable attention because of their unique optical properties and biocompatibility.In this work,we report an emission-tunable nanofluorophore constructed by the self-assembly of an amphiphilic block copolymer(denoted by PTN).The diblock copolymer was synthesized by RAFT polymerization.A polyethylene glycol-based trithiocarbonate was employed as the macromolecular chain transfer agent,and a near-infrared emitting tetraphenylethylene derivative with a vinyl terminal group was designed as the monomer.The block copolymers self-assembled in an aqueous solution to form nanospheres,which showed near-infrared emission at approximately 720 nm with a significant Stokes shift of approximately 260 nm.Furthermore,nanofluorophores have excellent biocompatibility,photostability,and pH-independent emission-tunable properties,and were successfully applied to label HeLa cells for fluorescence imaging.