No abstract

No abstract

Pole-to-pole oscillations of the Min proteins in Escherichia coli are required for the proper placement of the division septum. Direct interaction of MinE with the cell membrane is critical for the dynamic behavior of the Min system. In vitro, this MinE-membrane interaction led to membrane deformation; however, the underlying mechanism remained unclear. Here we report that MinE-induced membrane deformation involves the formation of an amphipathic helix of MinE2–9, which, together with the adjacent basic residues, function as membrane anchors. Biochemical evidence suggested that the membrane association induces formation of the helix, with the helical face, consisting of A2, L3, and F6, inserted into the membrane. Insertion of this helix into the cell membrane can influence local membrane curvature and lead to drastic changes in membrane topology. Accordingly, MinE showed characteristic features of protein-induced membrane tubulation and lipid clustering in in vitro reconstituted systems. In conclusion, MinE shares common protein signatures with a group of membrane trafficking proteins in eukaryotic cells. These MinE signatures appear to affect membrane curvature.

Flocculation is extensively employed for clarification through sedimentation. Application of ecofriendly plant-based bio-flocculants in wastewater treatment has attracted significant attention lately with high removal capability in terms of solids, turbidity, colour and dye. However, moderate flocculating property and short shelf life restrict their development. In order to enhance the flocculating ability, natural polysaccharides derived from plants are chemically modified by inclusion of synthetic, non-biodegradable monomers (e.g. acrylamide) onto their backbone to produce grafted bio-flocculants. This review is aimed to provide an overview of the development and flocculating efficiencies of plant-based bio-flocculants and grafted bio-flocculants for the first time. Furthermore, the processing methods, flocculation mechanism and the current challenges are discussed. All the reported studies about plant-derived bio-flocculants are conducted under lab-scale conditions in wastewater treatment. Hence, the possibility to apply natural bio-flocculants in food and beverage, mineral, paper and pulp, oleo-chemical and biodiesel industries is discussed and evaluated.