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Objective: To solve the problems of an uncertain fermentation process, a long fermentation period, and the unstable quality of traditional naturally fermented preserved fish. Methods: The lactic acid bacteria were isolated from low-salt preserved red fish, and the inhibition ability, salt tolerance, and acid production ability of the strains were investigated. The lactic acid bacteria suitable for fermentation were screened out, and the fermentation of preserved red fish was intensified by inoculation. The amount of red rice flour added, the amount of salt added during curing, and the fermentation temperature were optimized in the fermentation process. Results: There were 22 strains of Pediococcus with inhibitory effect on Escherichia coli or Staphylococcus aureus were isolated, among which Pediococcus pentosaceus P-56 had the best inhibitory effect on Escherichia coli and higher tolerance to bile salt and acid; After inoculation fermentation and process optimization. The pH value of the Zhayu decreased to 4.42 at 4 days of fermentation, the TCA-soluble peptide content was 434.99 μmol/g and the sensory score reached 45.7. Conclusion: The optimal process conditions for the fermentation of preserved red fish with lactic acid bacteria were: 4% salt addition for curing, 4% red yeast rice flour addition and fermentation temperature of 32 ℃.

Esterases/lipases from the GDSL family have potential applications in the hydrolysis and synthesis of important esters of pharmaceutical, food, and biotechnical interests. However, the structural and functional understanding of GDSL enzymes is still limited. Here, we report the crystal structure of the GDSL family esterase EstL5 complexed with PMSF at 2.34 Å resolution. Intriguingly, the PMSF binding site is not located at the active site pocket but is situated in a surface cavity. At the active site, we note that there is a trapped crystallization solvent 1,6-hexanediol, which mimics the bound ester chain, allowing for further definition of the active site pocket of EstL5. The most striking structural feature of EstL5 is the presence of a unique channel, which extends approximately 18.9 Å, with a bottleneck radius of 6.8 Å, connecting the active-site pocket and the surface cavity. Replacement of Ser205 with the bulk aromatic residue Trp or Phe could partially block the channel at one end and perturb its access. Reduced enzymatic activity is found in the EstL5 S205W and EstL5 S205F mutants, suggesting the functional relevance of the channel to enzyme catalysis. Our study provides valuable information regarding the properties of the GDSL-family enzymes for designing more efficient and robust biocatalysts.

Objective: Explore the cryoprotective mechanism and structure-activity relationship of antifreeze peptides derived from silver carp parvalbumin. Methods: Using differential scanning calorimetry and molecular dynamics simulation to compare activity, structure and mode of action of two typical peptides. Results: Pv-AFP 1 （KAADSFNH KAFFAKVG） had a stable α-helix structure, while Pv-AFP 2 （KAADSFNHKAF） tended to exhibit random coil. The thermal hysteresis activity of Pv-AFP 1 was 0.87 ℃, which was higher than Pv-AFP 2 （0.74 ℃）. Molecular dynamics simulations showed that Pv-AFP 1 could interact with 53 water molecules, and could form 16 hydrogen bonds to adsorb onto the surface of ice crystals, with a binding energy of -1 514 kJ/mol, all were greater than Pv-AFP 2 （can bind 50 water molecules, adsorb on ice surface by forming 11 hydrogen bonds, with a binding energy of -805 kJ/mol）. Despite the similarity of the two peptide sequences, their major sites and modes of interactions with water molecules and ice crystals were somewhat different. In addition, both peptides could interact with ice/water interface and altered the curvature of the ice surface, thereby inhibiting water freezing. But Pv-AFP 1 showed a better inhibitory effect on ice surface growth than Pv-AFP 2, which was consistent with their thermal hysteresis activity. Conclusion: The activities of antifreeze peptides derived from silver carp parvalbumin might be related to their structural characters and their affinities, sites and modes of interaction with water molecules and ice crystals.

To give full play to the role of fatigue supervision of intelligent monitoring platforms, We consider the shortage of the traditional management model of enterprises. The management game model of enterprises and drivers is built from the benefits of drivers. Taking 79 drivers of enterprise A in Jiaozuo City as an example, the number of fatigue violations of each driver in each of the six consecutive months was counted. Combined with the system clustering method, the drivers are classified according to the trend of the number of violations. Finally, different regulatory measures were proposed for different categories of drivers according to the evolution of the regulatory game system. The model evolution simulation results show that when the cost paid by the driver for violating the law (c) is greater than the additional benefit generated by the violation (d), the driver will choose not to drive fatigued to protect his benefits. The classification results show that drivers can be divided into four categories:① class no fatigue violation records; ② class fatigue violation records show a downward trend; ③ class fatigue violation records show wavy changes, indicating repeated violations; ④ class fatigue violation records show an upward trend. The number of violations varies for different categories of drivers. The d increases as the number of violations increases. Therefore, different management measures are proposed to increase c for the 4-type drivers so that the parameters of each type of driver satisfy the range of values of c>d. Thus, the driver evolves in the direction of no-fatigue driving. It can effectively regulate fatigue driving and improve driving safety.

In order to solve the difficult problem of dynamic driving detection in vehicle transportation for a long time, Jiaozuo Transportation Bureau took the lead in using 4G platform for dynamic supervision of driver behavior, so as to reduce driving accidents. According to the data provided by Jiaozuo freight company, this paper analyzes the internal relationship among vehicle qualified rate, 4G video vehicle monitoring and evaluation project score and alarm record. And according to the relationship between the three, we use SPSS software to analyze the correlation and cluster of freight companies, and study the closed-loop disposal and company policy of companies with good operation.

The Brusselator with different time scales, which behaves in the classical slow-fast effect, is investigated, and is characterized by the coupling of the quiescent and spiking states. In order to reveal the generation mechanism by using the slow-fast analysis method, the coordinate transformation is introduced into the classical Brusselator, so that the transformed system can be divided into the fast and slow subsystems. Furthermore, the stability condition and bifurcation phenomenon of the fast subsystem are analyzed, and the attraction domains of different equilibria are presented by theoretical analysis and numerical simulation respectively. Based on the transformed system, it could be found that the generation mechanism between the quiescent and spiking states is Fold bifurcation and change of the attraction domain of the fast subsystem. The results may also be helpful to the similar system with multiple time scales.