Proper longitudinal growth of long bones relies on the regulation of specific spatial patterns of chondrocyte proliferation and differentiation. We have studied the roles of two members of the Wnt family, Wnt5a and Wnt5b in long bone development. We show that Wnt5a is required for longitudinal skeletal outgrowth and that both Wnt5a and Wnt5b regulate the transition between different chondrocyte zones independently of the Indian hedgehog (Ihh)/parathyroid hormone-related peptide (PTHrP) negative feedback loop. We find that important cell cycle regulators such as cyclin D1 and p130, a member of the retinoblastoma family, exhibit complimentary expression patterns that correlate with the distinct proliferation and differentiation states of chondrocyte zones. Furthermore, we show that Wnt5a and Wnt5b appear to coordinate chondrocyte proliferation and differentiation by differentially regulating cyclin D1 and p130 expression, as well as chondrocyte-specific Col2a1 expression. Our data indicate that Wnt5a and Wnt5b control the pace of transitions between different chondrocyte zones.

Through their unique and specific interactions with various metal ions, naturally occurring proteins control structures and functions of many biological processes and functions in organisms. Inspired by natural metallopeptides, chemists have developed artificial peptides which coordinate with metal ions through their functional groups either for introducing a special reactivity or for constructing nanostructures. However, the design of new coordination peptides requires a deep understanding of the structures, assembly properties, and dynamic behaviours of such peptides. This review briefly discusses strategies of peptide self-assembly induced by metal coordination to different natural and non-natural binding sites in the peptide. The structures and functions of the obtained aggregates are described as well. We also highlight some examples of a metal-induced peptide self-assembly with relevance to biotechnology applications.

Mixed polydiacetylene (PDA) liposomes functionalized on their surface with a fluorescent pentalysine peptide derivative and histidine in a ratio of 1:9 can identify bacterial lipopolysaccharide (LPS). Upon photopolymerization of the self-assembled liposomes the initial fluorescence of the peptide-diacetylene amphiphiles is quenched. Interaction with LPS in aqueous solution or on the surface of E. coli DH5α restores the fluorescence. This increase in fluorescence is selective for LPS relative to other negatively charged analytes including nucleotides and ctDNA. This simple turn-on fluorescent sensor allows detecting LPS even at low micromolar concentrations.

This communication reports a unique example of water-soluble and fluorescent-switchable amphiphilic diarylethene. This compound performs stable vesicle aggregation in water and shows aggregation-dependent emission in its open form. The fluorescence can be effectively switched by alternating between UV and visible light irradiation. This compound thus can stain KB cells for switchable living cell imaging with excellent resistance to fatigue.

A pyrene-functionalized cationic oligopeptide 1 efficiently binds to double-stranded DNA, as shown by different spectrophotochemical studies. Upon binding, the conformation of 1 changes from a folded to an extended form, which leads to a distinct change in the fluorescence properties. Thus, 1 functions as a molecular peptide beacon, and as it is easily taken up by cells, 1 can also be used for imaging of nucleic acids within cells.