Biofabrication: an overview of the approaches used for printing of living cells

The development of cell printing is vital for establishing biofabrication approaches as clinically relevant tools. Achieving this requires bio-inks which must not only be easily printable, but also allow controllable and reproducible printing of cells. This review outlines the general principles and current progress and compares the advantages and challenges for the most widely used biofabrication techniques for printing cells: extrusion, laser, microvalve, inkjet and tissue fragment printing. It is expected that significant advances in cell printing will result from synergistic combinations of these techniques and lead to optimised resolution, throughput and the overall complexity of printed constructs

Characterization the Effects of Structure and Energetics of Intermolecular Interactions on the Oligomerization of Peptides in Aqueous 2, 2, 2-Trifluoroethanol via Circular Dichroism and Nuclear Magnetic Resonance Spectroscopy

[[abstract]]Intermolecular interactions are of fundamental importance to fully comprehend a wide range of protein behaviors such as oligomerization, folding and recognition. Two peptides, NPY [18-36] and NPY [15-29], segmented from human neuropeptide Y (hNPY), were synthesized in this work to study the interaction between species. Information about intermolecular interactions was extracted from their oligomerizing behaviors. The results from CD and NMR showed that the addition of 2, 2, 2-trifluoroeth-anol (TFE) induces a stable helix in each peptides and an extended helix in NPY [18-36], formed between residues 30-36. Pulsed field gradient NMR data revealed that NPY [15-29] forms a larger oligomer at lower temperatures and continuously dissociates into the monomeric form with increasing temperature. NPY [18-36] was also found to undergo an enhanced interaction with TFE and a more favorable self-association at higher temperatures. We characterized the changes of oligomerized states with respect to temperature to infer the effects of entropy and interaction energy on the association-dissociation equilibrium. As shown by NPY [15-29], deletion of helical secondary structure or residues from the C-terminal segment may disrupt the solvation by TFE and results in entropy increase as the oligomer dissociates. Unlike that in NPY [15-29], the extended helix in NPY [18-36] improves the binding of TFE, and as a result, entropy is gained via the transfer of the TFE cluster from the interface between monomeric peptides into the bulk solvent. This observation suggests that the oligomerized state may be modulated by the entropy and energetics contributed by helical segments in the oligomerization process.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子版[[countrycodes]]US

Reductive glutamine metabolism by IDH1 mediates lipogenesis under hypoxia

Acetyl coenzyme A (AcCoA) is the central biosynthetic precursor for fatty-acid synthesis and protein acetylation. In the conventional view of mammalian cell metabolism, AcCoA is primarily generated from glucose-derived pyruvate through the citrate shuttle and ATP citrate lyase in the cytosol. However, proliferating cells that exhibit aerobic glycolysis and those exposed to hypoxia convert glucose to lactate at near-stoichiometric levels, directing glucose carbon away from the tricarboxylic acid cycle and fatty-acid synthesis. Although glutamine is consumed at levels exceeding that required for nitrogen biosynthesis, the regulation and use of glutamine metabolism in hypoxic cells is not well understood. Here we show that human cells use reductive metabolism of α-ketoglutarate to synthesize AcCoA for lipid synthesis. This isocitrate dehydrogenase-1 (IDH1)-dependent pathway is active in most cell lines under normal culture conditions, but cells grown under hypoxia rely almost exclusively on the reductive carboxylation of glutamine-derived α-ketoglutarate for de novo lipogenesis. Furthermore, renal cell lines deficient in the von Hippel–Lindau tumour suppressor protein preferentially use reductive glutamine metabolism for lipid biosynthesis even at normal oxygen levels. These results identify a critical role for oxygen in regulating carbon use to produce AcCoA and support lipid synthesis in mammalian cells.National Institutes of Health (U.S.) (Grant R01 DK075850-01)American Cancer Society (Postdoctoral Fellowship)National Institutes of Health (U.S.)Burroughs Wellcome FundSmith Family FoundationDamon Runyon Cancer Research FoundationNational Cancer Institute (U.S.

The PLATO mission

PLATO (PLAnetary Transits and Oscillations of stars) is ESA’s M3 mission designed to detect and characterise extrasolar planets and perform asteroseismic monitoring of a large number of stars. PLATO will detect small planets (down to <2R $$_\textrm{Earth}$$ Earth ) around bright stars (<11 mag), including terrestrial planets in the habitable zone of solar-like stars. With the complement of radial velocity observations from the ground, planets will be characterised for their radius, mass, and age with high accuracy (5%, 10%, 10% for an Earth-Sun combination respectively). PLATO will provide us with a large-scale catalogue of well-characterised small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. It will make possible comparative exoplanetology to place our Solar System planets in a broader context. In parallel, PLATO will study (host) stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution. The payload instrument consists of 26 cameras with 12cm aperture each. For at least four years, the mission will perform high-precision photometric measurements. Here we review the science objectives, present PLATO‘s target samples and fields, provide an overview of expected core science performance as well as a description of the instrument and the mission profile towards the end of the serial production of the flight cameras. PLATO is scheduled for a launch date end 2026. This overview therefore provides a summary of the mission to the community in preparation of the upcoming operational phases.</p