Volume 10 Issue 5, May 2018

Volume 10 Issue 5

Magnetic manipulation to measure mRNA

Gene-expression studies are typically carried out in the bulk by pooling cells, but analysis of cell-to-cell variation — which is of particular interest for rare circulating tumour cells — requires techniques that can characterize levels of expression in individual cells. Now, a new technique that enables rare cells to be isolated from whole blood based on target mRNA sequences has been developed by a team led by Shana Kelley. The cover image depicts the mRNA-induced intracellular self-assembly of magnetic nanoparticles to form large magnetic clusters that enables the graded separation of individual cells based on their expression levels of the target mRNA

See Labib et al.

Image: Ella Maru Studio. Cover design: Tulsi Voralia

Thesis

  • Thesis |

    Bruce C. Gibb discusses the biochemistry behind the sensory experiences associated with eating chillies and the lesser-known tingle-inducing ‘sanshools’.

    • Bruce C. Gibb

News & Views

  • News & Views |

    Proteins are attractive material building blocks, yet their intrinsic functionality has remained largely untapped. Now, a protein-based material that exhibits controllable self-assembling behaviour has been prepared in a one-pot synthesis by simultaneous use of recombinant expression and post-translational modification.

    • Alvaro Mata

Articles

  • Article |

    Cell-to-cell variation in gene expression creates a need for techniques that characterize expression at the level of individual cells. Now, a technique for characterizing mRNA expression has been developed. The technique uses the intracellular self-assembly of magnetic nanoparticles to quantitate RNA levels at the single-cell level.

    • Mahmoud Labib
    • , Reza M. Mohamadi
    • , Mahla Poudineh
    • , Sharif U. Ahmed
    • , Ivaylo Ivanov
    • , Ching-Lung Huang
    • , Maral Moosavi
    • , Edward H. Sargent
    •  & Shana O. Kelley
  • Article |

    Inspired by the post-translational modifications of polypeptides widespread in biological systems, the one-pot synthesis of biohybrid materials was engineered within Escherichia coli using a recombinant expression and post-translational lipidation. The fatty-acid-modified elastin-like polypeptides (FAMEs) prepared, which comprise peptide-amphiphile segments prone to self-assembly fused to a thermally responsive elastin-like polypeptide, exhibit temperature-triggered hierarchical assembly.

    • Davoud Mozhdehi
    • , Kelli M. Luginbuhl
    • , Joseph R. Simon
    • , Michael Dzuricky
    • , Rüdiger Berger
    • , H. Samet Varol
    • , Fred C. Huang
    • , Kristen L. Buehne
    • , Nicholas R. Mayne
    • , Isaac Weitzhandler
    • , Mischa Bonn
    • , Sapun H. Parekh
    •  & Ashutosh Chilkoti
  • Article |

    A low-power laser can cause phase separation or trigger the nucleation of a new phase in the proximity of a liquid–liquid critical point, or binodal, using a laser tweezing potential. This effect explains the physics behind non-photochemical laser-induced nucleation and suggests new ways of manipulating matter.

    • Finlay Walton
    •  & Klaas Wynne
  • Article |

    Molecules that mimic the charge surface of B-DNA could enable the inhibition of DNA processive enzymes. Now, helically folded aromatic oligoamide scaffolds have been synthesized that display anions at positions similar to that of B-DNA phosphates. These foldamer mimics can recognize some DNA binding proteins and inhibit enzymes such as HIV integrase and topoisomerase 1.

    • Krzysztof Ziach
    • , Céline Chollet
    • , Vincent Parissi
    • , Panchami Prabhakaran
    • , Mathieu Marchivie
    • , Valentina Corvaglia
    • , Partha Pratim Bose
    • , Katta Laxmi-Reddy
    • , Frédéric Godde
    • , Jean-Marie Schmitter
    • , Stéphane Chaignepain
    • , Philippe Pourquier
    •  & Ivan Huc
  • Article |

    Collision-induced spin–orbit transitions involve multiple interaction potentials and are by nature non-adiabatic, complicating both their experimental and theoretical study. Crossed-beam experiments and non-Born–Oppenheimer quantum calculations for inelastic collisions of carbon atoms with helium atoms, down to energies corresponding to temperatures below 10 K, have now been performed. Quantum-dynamical resonances predicted by theory were experimentally detected.

    • Astrid Bergeat
    • , Simon Chefdeville
    • , Michel Costes
    • , Sébastien B. Morales
    • , Christian Naulin
    • , Uzi Even
    • , Jacek Kłos
    •  & François Lique
  • Article |

    Mapping energy landscapes has proved to be a powerful approach for studying reaction mechanisms. Now, this strategy has been applied to determine the activation energies and entropies that characterize the molecular steps in the misfolding and aggregation of the amyloid-β peptide, revealing striking differences between the thermodynamic signatures of primary and secondary nucleation.

    • Samuel I. A. Cohen
    • , Risto Cukalevski
    • , Thomas C. T. Michaels
    • , Anđela Šarić
    • , Mattias Törnquist
    • , Michele Vendruscolo
    • , Christopher M. Dobson
    • , Alexander K. Buell
    • , Tuomas P. J. Knowles
    •  & Sara Linse
  • Article |

    Mg-based batteries possess potential advantages over their lithium counterparts; however, the use of reversible oxidation-resistant, carbonate-based electrolytes has been hindered because of their undesirable electrochemical reduction reactions. Now, by engineering a Mg2+-conductive artificial interphase on a Mg electrode surface, which prevents such reactivity, highly reversible Mg deposition/stripping in carbonate-based electrolytes has been demonstrated.

    • Seoung-Bum Son
    • , Tao Gao
    • , Steve P. Harvey
    • , K. Xerxes Steirer
    • , Adam Stokes
    • , Andrew Norman
    • , Chunsheng Wang
    • , Arthur Cresce
    • , Kang Xu
    •  & Chunmei Ban
  • Article |

    Peptide macrocycles are uniquely suited to engage some challenging biological targets, such as protein–protein interactions. Inspired by the ‘C–H’ cross-linked peptide natural products, a highly efficient and generally applicable strategy for constructing cyclophane-braced peptide macrocycles has been developed. The strategy is based on palladium-catalysed intramolecular C(sp3)–H arylation reactions.

    • Xuekai Zhang
    • , Gang Lu
    • , Meng Sun
    • , Madhu Mahankali
    • , Yanfei Ma
    • , Mingming Zhang
    • , Wangde Hua
    • , Yuting Hu
    • , Qingbing Wang
    • , Jinghuo Chen
    • , Gang He
    • , Xiangbing Qi
    • , Weijun Shen
    • , Peng Liu
    •  & Gong Chen
  • Article |

    Molecular collisions can lead to the absorption of incident light even for transitions that are spectroscopically forbidden for the isolated molecules. Now the electronic–vibrational transitions of O2 have been theoretically studied and, contrary to textbook knowledge, it is shown that the absorption mechanism and the spectral line shape depend on the collision partner, oxygen or nitrogen.

    • Tijs Karman
    • , Mark A. J. Koenis
    • , Agniva Banerjee
    • , David H. Parker
    • , Iouli E. Gordon
    • , Ad van der Avoird
    • , Wim J. van der Zande
    •  & Gerrit C. Groenenboom
  • Article |

    The biosynthesis of the [FeFe] hydrogenase active site H-cluster requires several Fe–S proteins that perform poorly understood reactions. Now, a reaction intermediate trapped in the enzyme HydG is shown to contain a [(Cys)Fe(CO)(CN)] species identified as the first organometallic Fe moiety en route to the catalytic H-cluster.

    • Guodong Rao
    • , Lizhi Tao
    • , Daniel L. M. Suess
    •  & R. David Britt
  • Article |

    Scattering of molecules at low temperature that are prepared in single quantum states illuminates the mechanism of rotationally inelastic collisions and reveals the reorientation of partner molecules. By correlating each outgoing partial wave with the incoming waves, partial-wave analysis of the scattering angular distribution determines the dominant short- and long-range anisotropies of the interaction potential.

    • William E. Perreault
    • , Nandini Mukherjee
    •  & Richard N. Zare
  • Article |

    The M-cluster in the active site of nitrogenase is derived from an 8Fe core assembled via coupling and rearrangement of two [Fe4S4] clusters concomitant with the insertion of an interstitial carbon and a ninth sulfur. Now, by combining synthetic [Fe4S4] clusters and assembly with a protein template, it has been shown that sulfite gives rise to the ninth sulfur that is inserted into the nitrogenase cofactor after the radical SAM-dependent carbide insertion and cofactor core rearrangement.

    • Kazuki Tanifuji
    • , Chi Chung Lee
    • , Nathaniel S. Sickerman
    • , Kazuyuki Tatsumi
    • , Yasuhiro Ohki
    • , Yilin Hu
    •  & Markus W. Ribbe

Amendments & Corrections

In Your Element

  • In Your Element |

    Adrian Dingle relates how one ‘element’ that fell off the periodic table was eventually replaced by two.

    • Adrian Dingle