采用疏水改性纤维膜处理热镀锌废酸液实验研究

以高孔隙率的纤维膜为气液屏障,研究采用纤维膜的膜蒸馏技术在处理热镀锌废酸液过程中的可行性与效果.结果表明,疏水改性纤维膜对废酸液中含有的Fe2+的截留率大于99.9％,且废酸液温度越高,渗透通量越大,最大渗透通量约为3.2kg/(m2?h).膜蒸馏过程中,废酸液中的HCl挥发为气体穿过纤维膜,在冷凝侧冷凝为稀盐酸.废酸...     

Regulation of Lipid Bilayer Ion Permeability by Antibacterial Polymethyloxazoline-Polyethyleneimine Copolymers

Amphiphilic antimicrobial polymers display activity against the outer bacterial cell membrane, triggering various physiological effects. We investigated the regulation of ion transport across the lipid bilayer to understand differences in biological activity for a series of amphiphilic polymethyloxazoline – polyethyleneimine copolymers. The results confirmed that the tested structures were able to increase the permeability of the lipid bilayer (LB) membrane or its rupture. Black lipid membrane (BLM) experiments show that the triggered conductance profile and its character is strongly correlated with the polymer structure and zeta potential. The polymer exhibiting the highest antimicrobial activity promotes ion transport by using a unique mechanism and step-like characteristics with well-defined discreet openings and closings. The molecule was incorporated into the membrane in a reproducible way, and the observed channel-like activity could be responsible for the antibacterial activity of this molecule.     

The Escherichia coli Outer Membrane β-Barrel Assembly Machinery (BAM) Anchors the Peptidoglycan Layer by Spanning It with All Subunits

Gram-negative bacteria possess a three-layered envelope composed of an inner membrane, surrounded by a peptidoglycan (PG) layer, enclosed by an outer membrane. The envelope ensures protection against diverse hostile milieus and offers an effective barrier against antibiotics. The layers are connected to each other through many protein interactions. Bacteria evolved sophisticated machineries that maintain the integrity and the functionality of each layer. The β-barrel assembly machinery (BAM), for example, is responsible for the insertion of the outer membrane integral proteins including the lipopolysaccharide transport machinery protein LptD. Labelling bacterial cells with BAM-specific fluorescent antibodies revealed the spatial arrangement between the machinery and the PG layer. The antibody detection of each BAM subunit required the enzymatic digestion of the PG layer. Enhancing the spacing between the outer membrane and PG does not abolish this prerequisite. This suggests that BAM locally sets the distance between OM and the PG layer. Our results shed new light on the local organization of the envelope.