Effects of Antimicrobial Peptide Revealed by Simulations: Translocation, Pore Formation, Membrane Corrugation and Euler Buckling

We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling

Hydrodeoxygenation of Methyl Laurate over Ni Catalysts Supported on Hierarchical HZSM-5 Zeolite

The hierarchical HZSM-5 zeolite was prepared successfully by a simple NaOH treatment method. The concentration of NaOH solution was carefully tuned to optimal the zeolite acidity and pore structure. Under NaOH treatment conditions, a large number of mesopores, which interconnected with the retained micropores, were created to facilitate mass transfer performance. There are very good correlations between the decline of the relative zeolite crystallinity and the loss of micropores volume. The Ni nanoclusters were uniformly confined in the mesopores of hierarchical HZSM-5 by the excessive impregnation method. The direct deoxygenation in N2 and hydrodeoxygenation in H2 of the methyl laurate were compared respectively over the Ni/HZSM-5 catalysts. In the N2 atmosphere, the deoxygenation rate of the methyl laurate on the Ni/HZSM-5 catalyst is relatively slow. In the presence of H2, the synergistic effect between the hydrogenation function of the metal and the acid function of the zeolite supports can make the deoxygenation level more obvious. The yield of hydrocarbon products gradually reached the maximum with the appropriate treatment concentration of 1M NaOH, which could be attributed to the improved mass transfer in the hierarchical HZSM-5 supports

Immunoprotective evaluation of Escherichia coli outer membrane protein A against the main pathogens of animal mastitis

Purpose: To evaluate prokaryotic expression of the Escherichia coli (E. coli) outer membrane protein A (OmpA) and its immunoprotective function against the main pathogens of animal mastitis.Methods: A molecular cloning method was used to develop a prokaryotic strain expressing OmpA protein, which was purified by Ni-affinity  chromatography. Polyclonal antiserum was generated in mice immunized with OmpA protein. Enzyme-linked immunosorbent assay (ELISA) and western blotting were used to determine the titer and verify anti-OmpA serum specificity, respectively. Interaction between OmpA antiserum and main pathogens of animal mastitis was verified by ELISA and a pull-down method. The immune protective function of OmpA protein was evaluated in mice challenged with pathogens of animal mastitis. Optimal fermentation conditions to produce OmpA protein were determined by the L9(34) orthogonal test.Results: A prokaryotic strain expressing OmpA protein was developed, and purified OmpA was used to develop a mouse polyclonal antibody. The anti-OmpA serum exhibited high specificity and a titer of 1:1600. Anti-OmpA serum directly interacted with E. coli and Staphylococcus aureus (S. aureus). OmpA demonstrated a significant immune protective function of 58.33 % against E. coli and 46.15 % against S. aureus. The optimal conditions for expressing fermentation OmpA were a strain absorbance of 0.5 at a wavelength of 600 nm, IPTG final concentration of 0.3 mmol/L, induction time of 12 h, and induction temperature of 28 °C.Conclusion: OmpA possesses selective immunogenicity and a significant immune protective effect against the main pathogens of animal mastitis. The results suggest that OmpA may potentially be used as a vaccine for animal mastitis. Keywords: E. coli, OmpA protein, Immunoprotection, Animal mastitis, Protein fermentatio

Why has the birth rate relatively increased in China's wealthy cities?

China’s wealthy cities tended to have low birth rates in past decades, but this relationship has disappeared in conjunction with the substantial relaxation of the one-child policy after 2011. This study develops a conceptual framework for the relationship between average household wealth and compliance with the one-child policy across cities and concludes that the compliance rate was greater in wealthier cities when above-quota births were fined according to household wealth and with limited liability. The relaxation of this policy has eliminated this inequality, leading to an increase in wealthy cities’ birth rates relative to those of other cities. A causal analysis exploiting variations in city-level birth rates and fertility policy compliance rates from 2008 to 2019 supports our hypotheses. Moreover, our results suggest that the fertility relaxation has resulted in a greater proportion of newborns in wealthy cities, which is expected to increase the next generation’s human capital