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Biomimetic protein membranes have attracted increasing interests because of their distinctive separation properties in the membrane field. Low-cost and stable protein lysozyme has been intensively invetigated to fabricate high-performance sepration membranes via a facile and scalable method of amyloid-like assembly. However, the pore formation mechnism of the lysozyme membrane remains unclear. Herein, the lysozyme membranes were fabricated and the membrane formation mechnism and separation properties were investigated experimentally. Molecular dynamics simulation (MDS) was also employed to reveal the pore formation mechanism of the lysozyme membrane. The fabricated lysozyme membrane achieved a stable high water permeance of 10.2 L m−2 h−1 bar−1, as well as a relatively high separation factor (9.5) towards antibiotic and sodium chloride. MDS results found that the membrane pore size is governed by the amino acid compositions and is negatively dependent on the intermolecular forces among amino acids around the pores. Selective pores with 0.54 nm in diameter are primarily formed by these amino acids including alanine (35 %), aspartic acid (25 %), arginine (15 %), phenylalanine (11 %), and lysine (7 %), in which half of them have hydrophobic side chains with no charge, and another half have hydrophilic side chains with balanced charges. This work may stimulate the development of highly permeable and selective protein membranes by carefully engineering their amino acid compositions with optimal charges and hydrophobicity for generation of numerous selective pores. [Display omitted] • Nanofiltration membranes were fabricated by amyloid-like assembly of lysozyme. • Formation mechanism of lysozyme membrane on porous substrate was investigated. • Pore formation mechanism of lysozyme was studied. • The CV rejection and separation factor towards ERY/NaCl were 99.9 % and 9.5. [ABSTRACT FROM AUTHOR]

Pesticide overuse is a major global problem and the cause of this problem is noticeable pesticide loss from undesired bouncing of sprayed pesticide droplets and rain erosion. This further becomes a primary source of soil and groundwater pollution. Herein, the authors report a method that can enhance pesticide droplet deposition and adhesion on superhydrophobic plant leave surfaces by amyloid‐like aggregation of bovine serum albumin (BSA). Through the reduction of the disulfide bond of BSA by tris(2‐carboxyethyl) phosphine hydrochloride (TCEP), the amyloid‐like phase transition of BSA is triggered that rapidly affords abundant phase‐transitioned BSA (PTB) oligomers to facilitate the invasion of the PTB droplet into the nanostructures on a leaf surface. Such easy penetration is further followed by a robust amyloid‐mediated interfacial adhesion of PTB on leaf surface. As a result, after mixing with pesticides, the PTB system exhibits a remarkable pesticide adhesion capacity that is more than 10 times higher than conventional fixation of commercial pesticides. The practical farmland experiments show that the use of PTB aggregation could reduce the use of pesticides by 70–90% while ensuring yield. This work demonstrates that current pesticide dosage in actual agriculture production may be largely reduced by utilizing eco‐friendly amyloid‐like protein aggregation. [ABSTRACT FROM AUTHOR]

Abstract Pesticide overuse is a major global problem and the cause of this problem is noticeable pesticide loss from undesired bouncing of sprayed pesticide droplets and rain erosion. This further becomes a primary source of soil and groundwater pollution. Herein, the authors report a method that can enhance pesticide droplet deposition and adhesion on superhydrophobic plant leave surfaces by amyloid‐like aggregation of bovine serum albumin (BSA). Through the reduction of the disulfide bond of BSA by tris(2‐carboxyethyl) phosphine hydrochloride (TCEP), the amyloid‐like phase transition of BSA is triggered that rapidly affords abundant phase‐transitioned BSA (PTB) oligomers to facilitate the invasion of the PTB droplet into the nanostructures on a leaf surface. Such easy penetration is further followed by a robust amyloid‐mediated interfacial adhesion of PTB on leaf surface. As a result, after mixing with pesticides, the PTB system exhibits a remarkable pesticide adhesion capacity that is more than 10 times higher than conventional fixation of commercial pesticides. The practical farmland experiments show that the use of PTB aggregation could reduce the use of pesticides by 70–90% while ensuring yield. This work demonstrates that current pesticide dosage in actual agriculture production may be largely reduced by utilizing eco‐friendly amyloid‐like protein aggregation.

[Display omitted] • The oxidation index raw pecan oil increased with storage time. • The oleosome structures were related to the degree of pecan kernel oxidation. • The hydrolysis of endogenous proteins, mainly oleosins, caused the rupture of the oleosomes. • Pecan kernel oil oxidation was accelerated by oleosome rupture. The oxidative stability of pecan kernels and its relationship with the in-vitro behavior of oleosomes during storage were analyzed. The oxidation index of oil extracted from pecans stored for 20 days increased significantly. At the same time oleosomes in pecans were damaged, indicating a relationship between oleosomes and the oxidative stability of pecans. The rupture of oleosomes increases contact between oil and oxygen leading to an acceleration of oil oxidation. Further analysis of oleosomes showed that their oil content decreased during storage while their particle size increased significantly. It is possible that hydrolysis of endogenous proteins, especially oleosins, was responsible for the rupture of oleosomes, as seen by Tricine-SDS-PAGE. As a result, the content of free fatty acids and oxidized triacylglycerols in oleosomes increased, whereas the polyunsaturated fatty acids content decreased significantly. An in-vitro model confirmed that rupture of oleosomes led to oil leakage and thus accelerated endogenous oil oxidation. [ABSTRACT FROM AUTHOR]

Abstract: True diffusion (Dm) and partition (α) coefficients for the transport of potassium ferrocyanide through diaphorase (Dp)– and bovine serum albumin (BSA)–glutaraldehyde (GA) membranes with different cross-linking degrees of 1–8% GA concentrations immobilized on gold electrodes are investigated by using potential-step method and rotating-disk-electrode method. The thickness of dry and hydrated immobilized membranes is accurately measured by the focus-difference method with a reflection microscope. The thickness of hydrated Dp–GA and BSA–GA membranes are about 1.4 and 2.4 times that of dry membranes, respectively. In addition, the actual area of electrode surface is calculated by the charge amount of chemisorbed oxygen on gold electrode. Owing to the increase of swelling degree and net negative charge of the immobilized membranes, the values of Dm and α for both of Dp–GA and BSA–GA membranes enlarge and decrease with increase of GA concentration, respectively. Furthermore, BSA–GA membranes possess greater Dm and α than those of Dp–GA membranes due to the thinner thickness and the greater swelling degree of BSA–GA membranes. [Copyright &y& Elsevier]

We report transmission electron microscopy (TEM) investigations on bacterial surface layers (S-layers) which belong to the simplest biomembranes existing in nature. S-layers are regular 2D protein crystals composed of single protein or glycoprotein species. In their native form, S-layers are weak phase objects giving only poor contrast in conventional TEM. Therefore, they are usually examined negatively stained. However, staining with heavy metal compounds may cause the formation of structural artefacts. In this work, electron microscopy studies of non-stained S-layers of Bacillus sphaericus NCTC 9602 were performed. Compared to other proteins, these S-layers are found relatively stable against radiation damage. Electron holography was applied where information about phase and amplitude of the diffracted electron wave is simultaneously obtained. In spite of small phase shifts observed, the phase image reconstructed from the hologram of the non-stained S-layer is found to be sensitive to rather slight structure and thickness variations. The lateral resolution, obtained so far, is less than that of conventional electron microscopy of negatively stained S-layers. It corresponds to the main lattice planes of 12.4 nm observed in the reconstructed electron phase image. In addition, as a unique feature of electron holography the phase image provides thickness information. Thus, the existence of double layers of the protein crystals could be easily visualized by the height profile of the specimen. [Copyright &y& Elsevier]

Organic solvent nanofiltration (OSN) is regarded as a promising separation technology in chemical and pharmaceutical industries. However, it remains a great challenge in fabricating OSN membranes with high permeability and precise selectivity by simple, transfer-free, and up-scalable processes. Herein, we report lysozyme nanofilm composite membranes (LNCM) prepared by one-step methods with hydrophobic substrates at the air/water interface. The microporous substrates not only promote the heterogeneous nucleation of amyloid-like lysozyme oligomers to construct small pores in the formed nanofilms but also benefit for the simultaneous composition of LNCM via hydrophobic interactions. The constructed nanopores are reduced to around 1.0 nm, and they are demonstrated by grazing incidence small-angle X-ray scattering with a closely packed model. The LNCM can tolerate most organic polar solvents and the permeability surpasses most of state-of-the-art OSN membranes.