We investigated the growth of biosynthetic protein polymers with templated curvature on pluronic nanospheres. The protein has a central silk-like block containing glutamic residues (SE) and ...collagen-like end-blocks (C). The SE blocks stack into filaments when their charge is removed (pH <5). Indeed, at low pH curved and circular fibers are formed at the surface of the nanospheres, which keep their shape after removal of the pluronics. The data reveal the mechanism of the templated fibril-growth: The growth of protein assemblies is nucleated in solution; small protein fibrils adsorb on the nanospheres, presumably due to hydrogen bond formation between the silk-like blocks and the pluronic PEO blocks. The surface of the pluronic particles templates further growth. At relatively low protein/pluronic weight ratios, only a fraction of the nanospheres bears protein fibers, pointing to a limiting amount of nuclei in solution. Because the nanospheres capture fibrils at an early stage of growth, they can be used to separate growth and nucleation rates in protein fibril formation. Moreover, the nanoparticle-templated growth of stable curved fibers opens ways to build proteinaceous nanocapsules from designed protein polymers.
Introduction: Severe hypoglycemia is an ongoing barrier to achieving glycemic targets. Glucagon is an effective, yet underutilized treatment for severe hypoglycemia. This study characterized the ...emotional impact of severe hypoglycemia, glucagon perceptions, and barriers to glucagon use for people with T1D.
Methods: Participants included individuals recruited from the T1D Exchange online community. The current study conducted 7 focus groups consisting of adults with T1D (n = 38, average age 49.4, SD = 16.11 years). Average duration of diabetes was 34.4 years (SD = 17.3) and average self-reported A1c was 6.8% (SD = 0.7). Focus groups were recorded, transcribed, and thematically analyzed.
Results: A range of emotions was expressed about severe hypoglycemia including fear, anxiety, stress, frustration, shame, and embarrassment. Due to hypoglycemia unawareness, participants discussed relying on CGM to make hypoglycemia treatment decisions. Multiple participants self-administered glucagon to prevent or treat a severe hypoglycemic event. Although overnight hypoglycemia and CGM alarms were described as important, some participants also viewed them as sleep disruptors for themselves and their partners. Participants frequently identified prescription cost and insurance deductibles as barriers to glucagon use. Participants were also concerned about ease of administration—how difficult it is to prepare the glucagon in an emergency situation. Many participants expressed a preference for auto-injectables over nasal administration. Timing of glucagon action and time to recovery were high priorities. Some participants, while they had not self-administered glucagon, were interested in a mini-dose glucagon they could self-administer.
Conclusions: These results provide insight into the real-world impact of diabetes management in persons with T1D and highlight the attitudes about severe hypoglycemia and emergency glucagon treatment.
Disclosure
A. Hughes: None. K. S. M. Chapman: None. J. Bispham: None. N. M. Heydarian: None. J. Dimsits: Employee; Self; Zealand Pharma A/S. S. A. Weinzimer: Advisory Panel; Self; Dompe, Zealand Pharma A/S, Speaker’s Bureau; Self; Medtronic. W. Wolf: None.
Islands support unique plants, animals, and human societies found nowhere else on the Earth. Local and global stressors threaten the persistence of island ecosystems, with invasive species being ...among the most damaging, yet solvable, stressors. While the threat of invasive terrestrial mammals on island flora and fauna is well recognized, recent studies have begun to illustrate their extended and destructive impacts on adjacent marine environments. Eradication of invasive mammals and restoration of native biota are promising tools to address both island and ocean management goals. The magnitude of the marine benefits of island restoration, however, is unlikely to be consistent across the globe. We propose a list of six environmental characteristics most likely to affect the strength of land-sea linkages: precipitation, elevation, vegetation cover, soil hydrology, oceanographic productivity, and wave energy. Global databases allow for the calculation of comparable metrics describing each environmental character across islands. Such metrics can be used today to evaluate relative potential for coupled land-sea conservation efforts and, with sustained investment in monitoring on land and sea, can be used in the future to refine science-based planning tools for integrated land-sea management. As conservation practitioners work to address the effects of climate change, ocean stressors, and biodiversity crises, it is essential that we maximize returns from our management investments. Linking efforts on land, including eradication of island invasive mammals, with marine restoration and protection should offer multiplied benefits to achieve concurrent global conservation goals.
We study the self-assembly of genetically engineered protein-based triblock copolymers consisting of a central pH-responsive silk-like middle block (SH n , where SH is a silk-like octapeptide, ...(GA)3GH and n is the number of repeats) flanked by hydrophilic random coil outer blocks (C2). Our previous work has already shown that triblocks with very long midblocks (n = 48) self-assemble into long, stiff protein filaments at pH values where the middle blocks are uncharged. Here we investigate the self-assembly behavior of the triblock copolymers for a range of midblock lengths, n = 8, 16, 24, 48. Upon charge neutralization of SH n by adjusting the pH, we find that C2SH 8C2 and C2SH 16C2 form spherical micelles, whereas both C2SH 24C2 and C2SH 48C2 form protein filaments with a characteristic beta-roll secondary structure of the silk midblocks. Hydrogels formed by C2SH 48C2 are much stronger and form much faster than those formed by C2SH 24C2. Enzymatic digestion of much of the hydrophilic outer blocks is used to show that with much of the hydrophilic outer blocks removed, all silk-midblocks are capable of self-assembling into stiff protein filaments. In that case, reduction of the steric repulsion by the hydrophilic outer blocks also leads to extensive fiber bundling. Our results highlight the opposing roles of the hydrophilic outer blocks and central silk-like midblocks in driving protein filament formation. They provide crucial information for future designs of triblock protein-based polymers that form stiff filaments with controlled bundling, that could mimick properties of collagen in the extracellular matrix.
We produced several pH-responsive silk-collagen-like triblocks, one acidic and two alkaline. At pH values where the silk-like block is uncharged the triblocks self-assemble into filaments. The ...pH-induced self-assembly was examined by atomic force microscopy, light scattering, and circular dichroism. The populations of filaments were found to be very monodisperse, indicating that the filaments start to grow from already present nuclei in the sample. The growth then follows pseudo-first-order kinetics for all examined triblocks. When normalized to the initial concentration, the growth curves of each type of triblock overlap, showing that the self-assembly is a generic process for silk-collagen-silk triblocks, regardless of the nature of their chargeable groups. The elongation speed of the filaments is slow, due to the presence of repulsive collagen-like blocks and the limited number of possibilities for an approaching triblock to successfully attach to a growing end. The formation of filaments is fully reversible. Already present filaments can start growing again by addition of new triblocks. The structure of all filaments is very rich in β-turns, leading to β-rolls. The triblocks attain this structure only when attaching to a growing filament.
Controlled differentiation of human embryonic stem cells (hESCs) can be utilized for precise analysis of cell type identities during early development. We established a highly efficient neural ...induction strategy and an improved analytical platform, and determined proteomic and phosphoproteomic profiles of hESCs and their specified multipotent neural stem cell derivatives (hNSCs). This quantitative dataset (nearly 13,000 proteins and 60,000 phosphorylation sites) provides unique molecular insights into pluripotency and neural lineage entry. Systems-level comparative analysis of proteins (e.g., transcription factors, epigenetic regulators, kinase families), phosphorylation sites, and numerous biological pathways allowed the identification of distinct signatures in pluripotent and multipotent cells. Furthermore, as predicted by the dataset, we functionally validated an autocrine/paracrine mechanism by demonstrating that the secreted protein midkine is a regulator of neural specification. This resource is freely available to the scientific community, including a searchable website, PluriProt.
•Controlled neural induction produces pure cultures of PAX6+ neural stem cells•Most comprehensive (phospho)proteome mapping in pluripotent and multipotent cells•Prediction and validation of midkine as regulator of neural lineage commitment•Searchable and publicly available website presenting (phospho)proteomic dataset
Snyder, Brill, Singec, and colleagues demonstrate detailed analysis of human pluripotency and controlled neural lineage entry by using quantitative label-free (phospho)proteomics. The accuracy of the large dataset (13,000 proteins; 60,000 non-redundant phosphorylation sites) allows precise characterization and comparison of pluripotent and multipotent “stemness.” Functional follow-up experiments validate that the understudied protein midkine controls neuralization of hESCs.
•500nm size nano-pillar device was fabricated by photolithography techniques.•A magnetic hybrid structure was achieved with perpendicular magnetic fields.•Spin torque switching and oscillation was ...demonstrated in the large sized device.•Micromagnetic simulations accurately reproduced the experimental results.•Simulations demonstrated the synchronization of magnetic inhomogeneities.
DC current induced magnetization reversal and magnetization oscillation was observed in 500nm large size Co90Fe10/Cu/Ni80Fe20 pillars. A perpendicular external field enhanced the coercive field separation between the reference layer (Co90Fe10) and free layer (Ni80Fe20) in the pseudo spin valve, allowing a large window of external magnetic field for exploring the free-layer reversal. A magnetic hybrid structure was achieved for the study of spin torque oscillation by applying a perpendicular field >3kOe. The magnetization precession was manifested in terms of the multiple peaks on the differential resistance curves. Depending on the bias current and applied field, the regions of magnetic switching and magnetization precession on a dynamical stability diagram has been discussed in details. Micromagnetic simulations are shown to be in good agreement with experimental results and provide insight for synchronization of inhomogeneities in large sized device. The ability to manipulate spin-dynamics on large size devices could be proved useful for increasing the output power of the spin-transfer nano-oscillators (STNOs).
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