Complement-mediated killing of Escherichia coli by mechanical destabilization of the cell envelope.

Complement proteins eliminate Gram-negative bacteria in the blood via the formation of membrane attack complex (MAC) pores in the outer membrane. However, it remains unclear how outer membrane poration leads to inner membrane permeation and cell lysis. Using atomic force microscopy (AFM) on living Escherichia coli (E.

Phase separation in the outer membrane of .

Gram-negative bacteria are surrounded by a protective outer membrane (OM) with phospholipids in its inner leaflet and lipopolysaccharides (LPS) in its outer leaflet. The OM is also populated with many β-barrel outer-membrane proteins (OMPs), some of which have been shown to cluster into supramolecular assemblies. However, it remains unknown how abundant OMPs are organized across the entire bacterial surface and how this relates to the lipids in the membrane.

Resolving protein mixtures using microfluidic diffusional sizing combined with synchrotron radiation circular dichroism.

Circular dichroism spectroscopy has become a powerful tool to characterise proteins and other biomolecules. For heterogeneous samples such as those present for interacting proteins, typically only average spectroscopic features can be resolved. Here we overcome this limitation by using free-flow microfluidic size separation in-line with synchrotron radiation circular dichroism to resolve the secondary structure of each component of a model protein mixture containing monomers and fibrils.

Rapid Growth of Acetylated Aβ(16-20) into Macroscopic Crystals.

Aberrant assembly of the amyloid-β (Aβ) is responsible for the development of Alzheimer's disease, but can also be exploited to obtain highly functional biomaterials. The short Aβ fragment, KLVFF (Aβ), is crucial for Aβ assembly and considered to be an Aβ aggregation inhibitor. Here, we show that acetylation of KLVFF turns it into an extremely fast self-assembling molecule, reaching macroscopic ( i.

Nanostructural Differentiation and Toxicity of Amyloid-β25-35 Aggregates Ensue from Distinct Secondary Conformation.

Amyloid nanostructures are originated from protein misfolding and aberrant aggregation, which is associated with the pathogenesis of many types of degenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease. The secondary conformation of peptides is of a fundamental importance for aggregation and toxicity of amyloid peptides. In this work, Aβ25-35, a fragment of amyloid β(1-42) (Aβ42), was selected to investigate the correlation between secondary structures and toxicity of amyloid fibrils.

Thermal effect on the degradation of hIAPP fibrils.

Uncontrolled misfolding of proteins resulting in the formation of amyloid deposits is associated with over 40 types of diseases, for instance, type-2 diabetes. The human Islet amyloid polypeptide (hIAPP) amyloid formation is thought to be the cause of type-2 diabetes occurrence. A possible strategy to the current challenge of reducing the toxicity of its aggregates to pancreatic β-cell is the discovery of an efficient way to degrading amyloid deposits.

Light-driven porphyrin modulating fibrillation of hIAPP(20-29) peptide.

The human Islet amyloid polypeptide (20-29) (hIAPP) is considered to be the core fibrillating fragment of hIAPP, which is associated with the pathogenesis of Type-II diabetes mellitus. A current challenge is the discovery of an efficient way to modulate amyloid aggregation and inhibit the toxicity of its aggregates. In this work, photoexcited porphyrins are successfully used to inhibit the fibrillation of hIAPP.

Nanoliposomes containing Eucalyptus citriodora as antibiotic with specific antimicrobial activity.

Bacterial infections are a serious issue for public health and represent one of the major challenges of modern medicine. In this work, a selective antimicrobial strategy based on triggering of pore-forming toxin, which is secreted by infective bacteria, was designed to fight Staphylococcus aureus. The antimicrobial activity is realized by employing Eucalyptus citriodora oil as antibiotic which in this study is encapsulated in nanoliposomes.

A self-assembled nanopatch with peptide-organic multilayers and mechanical properties.

Peptides enable the construction of a diversity of one-dimensional (1D) and zero-dimensional (0D) nanostructures by molecular self-assembly. To date, it is a great challenge to construct two-dimensional (2D) nanostructures from peptides. Here we introduce an organic molecule to tune the amphiphilic-like peptide assembly to form a peptide-organic 2D nanopatch structure.

The position of hydrophobic residues tunes peptide self-assembly.

The final structure and properties of synthetic peptides mainly depend on their sequence composition and experimental conditions. This work demonstrates that a variation in the positions of hydrophobic residues within a peptide sequence can tune the self-assembly. Techniques employed are atomic force microscopy, transmission electron microscopy and an innovative method based on surface acoustic waves.

Ag-CuFeO magnetic hollow fibers for recyclable antibacterial materials.

Copper ferrite (CuFeO) magnetic hollow fibers were prepared by applying an organic sol-thermal decomposition method, and silver nanoparticles were subsequently loaded on the fibers by calcination. The Ag-CuFeO fibers exhibited excellent antibacterial efficacy against four different bacteria (E. coli, S.