TY - JOUR AB - Metazoan development relies on the formation and remodeling of cell-cell contacts. Dynamic reorganization of adhesion receptors and the actomyosin cell cortex in space and time plays a central role in cell-cell contact formation and maturation. Nevertheless, how this process is mechanistically achieved when new contacts are formed remains unclear. Here, by building a biomimetic assay composed of progenitor cells adhering to supported lipid bilayers functionalized with E-cadherin ectodomains, we show that cortical F-actin flows, driven by the depletion of myosin-2 at the cell contact center, mediate the dynamic reorganization of adhesion receptors and cell cortex at the contact. E-cadherin-dependent downregulation of the small GTPase RhoA at the forming contact leads to both a depletion of myosin-2 and a decrease of F-actin at the contact center. At the contact rim, in contrast, myosin-2 becomes enriched by the retraction of bleb-like protrusions, resulting in a cortical tension gradient from the contact rim to its center. This tension gradient, in turn, triggers centrifugal F-actin flows, leading to further accumulation of F-actin at the contact rim and the progressive redistribution of E-cadherin from the contact center to the rim. Eventually, this combination of actomyosin downregulation and flows at the contact determines the characteristic molecular organization, with E-cadherin and F-actin accumulating at the contact rim, where they are needed to mechanically link the contractile cortices of the adhering cells. AU - Arslan, Feyza N AU - Hannezo, Edouard B AU - Merrin, Jack AU - Loose, Martin AU - Heisenberg, Carl-Philipp J ID - 14795 IS - 1 JF - Current Biology SN - 0960-9822 TI - Adhesion-induced cortical flows pattern E-cadherin-mediated cell contacts VL - 34 ER - TY - JOUR AB - Frequency-stable lasers form the back bone of precision measurements in science and technology. Such lasers typically attain their stability through frequency locking to reference cavities. State-of-the-art locking performances to date had been achieved using frequency modulation based methods, complemented with active drift cancellation systems. We demonstrate an all passive, modulation-free laser-cavity locking technique (squash locking) that utilizes changes in spatial beam ellipticity for error signal generation, and a coherent polarization post-selection for noise resilience. By comparing two identically built proof-of-principle systems, we show a frequency locking instability of 5×10−7 relative to the cavity linewidth at 10 s averaging. The results surpass the demonstrated performances of methods engineered over the last five decades, potentially enabling an advancement in the precision control of lasers, while creating avenues for bridging the performance gaps between industrial grade lasers with scientific ones due to the afforded simplicity and scalability. AU - Diorico, Fritz R AU - Zhutov, Artem AU - Hosten, Onur ID - 14802 IS - 1 JF - Optica KW - Atomic and Molecular Physics KW - and Optics KW - Electronic KW - Optical and Magnetic Materials SN - 2334-2536 TI - Laser-cavity locking utilizing beam ellipticity: accessing the 10−7 instability scale relative to cavity linewidth VL - 11 ER - TY - JOUR AB - We consider a natural problem dealing with weighted packet selection across a rechargeable link, which e.g., finds applications in cryptocurrency networks. The capacity of a link (u, v) is determined by how many nodes u and v allocate for this link. Specifically, the input is a finite ordered sequence of packets that arrive in both directions along a link. Given (u, v) and a packet of weight x going from u to v, node u can either accept or reject the packet. If u accepts the packet, the capacity on link (u, v) decreases by x. Correspondingly, v's capacity on increases by x. If a node rejects the packet, this will entail a cost affinely linear in the weight of the packet. A link is “rechargeable” in the sense that the total capacity of the link has to remain constant, but the allocation of capacity at the ends of the link can depend arbitrarily on the nodes' decisions. The goal is to minimise the sum of the capacity injected into the link and the cost of rejecting packets. We show that the problem is NP-hard, but can be approximated efficiently with a ratio of (1+E) . (1+3) for some arbitrary E>0. AU - Schmid, Stefan AU - Svoboda, Jakub AU - Yeo, Michelle X ID - 14820 JF - Theoretical Computer Science KW - General Computer Science KW - Theoretical Computer Science SN - 0304-3975 TI - Weighted packet selection for rechargeable links in cryptocurrency networks: Complexity and approximation VL - 989 ER - TY - JOUR AB - Superconductor/semiconductor hybrid devices have attracted increasing interest in the past years. Superconducting electronics aims to complement semiconductor technology, while hybrid architectures are at the forefront of new ideas such as topological superconductivity and protected qubits. In this work, we engineer the induced superconductivity in two-dimensional germanium hole gas by varying the distance between the quantum well and the aluminum. We demonstrate a hard superconducting gap and realize an electrically and flux tunable superconducting diode using a superconducting quantum interference device (SQUID). This allows to tune the current phase relation (CPR), to a regime where single Cooper pair tunneling is suppressed, creating a sin(2y) CPR. Shapiro experiments complement this interpretation and the microwave drive allows to create a diode with ≈ 100% efficiency. The reported results open up the path towards integration of spin qubit devices, microwave resonators and (protected) superconducting qubits on the same silicon technology compatible platform. AU - Valentini, Marco AU - Sagi, Oliver AU - Baghumyan, Levon AU - de Gijsel, Thijs AU - Jung, Jason AU - Calcaterra, Stefano AU - Ballabio, Andrea AU - Aguilera Servin, Juan L AU - Aggarwal, Kushagra AU - Janik, Marian AU - Adletzberger, Thomas AU - Seoane Souto, Rubén AU - Leijnse, Martin AU - Danon, Jeroen AU - Schrade, Constantin AU - Bakkers, Erik AU - Chrastina, Daniel AU - Isella, Giovanni AU - Katsaros, Georgios ID - 14793 JF - Nature Communications TI - Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium VL - 15 ER - TY - JOUR AB - We study a random matching problem on closed compact 2 -dimensional Riemannian manifolds (with respect to the squared Riemannian distance), with samples of random points whose common law is absolutely continuous with respect to the volume measure with strictly positive and bounded density. We show that given two sequences of numbers n and m=m(n) of points, asymptotically equivalent as n goes to infinity, the optimal transport plan between the two empirical measures μn and νm is quantitatively well-approximated by (Id,exp(∇hn))#μn where hn solves a linear elliptic PDE obtained by a regularized first-order linearization of the Monge-Ampère equation. This is obtained in the case of samples of correlated random points for which a stretched exponential decay of the α -mixing coefficient holds and for a class of discrete-time Markov chains having a unique absolutely continuous invariant measure with respect to the volume measure. AU - Clozeau, Nicolas AU - Mattesini, Francesco ID - 14797 JF - Probability Theory and Related Fields SN - 0178-8051 TI - Annealed quantitative estimates for the quadratic 2D-discrete random matching problem ER - TY - JOUR AB - Mosaic analysis with double markers (MADM) technology enables the sparse labeling of genetically defined neurons. We present a protocol for time-lapse imaging of cortical projection neuron migration in mice using MADM. We describe steps for the isolation, culturing, and 4D imaging of neuronal dynamics in MADM-labeled brain tissue. While this protocol is compatible with other single-cell labeling methods, the MADM approach provides a genetic platform for the functional assessment of cell-autonomous candidate gene function and the relative contribution of non-cell-autonomous effects. For complete details on the use and execution of this protocol, please refer to Hansen et al. (2022),1 Contreras et al. (2021),2 and Amberg and Hippenmeyer (2021).3 AU - Hansen, Andi H AU - Hippenmeyer, Simon ID - 14794 IS - 1 JF - STAR Protocols TI - Time-lapse imaging of cortical projection neuron migration in mice using mosaic analysis with double markers VL - 5 ER - TY - JOUR AB - The plant-signaling molecule auxin triggers fast and slow cellular responses across land plants and algae. The nuclear auxin pathway mediates gene expression and controls growth and development in land plants, but this pathway is absent from algal sister groups. Several components of rapid responses have been identified in Arabidopsis, but it is unknown if these are part of a conserved mechanism. We recently identified a fast, proteome-wide phosphorylation response to auxin. Here, we show that this response occurs across 5 land plant and algal species and converges on a core group of shared targets. We found conserved rapid physiological responses to auxin in the same species and identified rapidly accelerated fibrosarcoma (RAF)-like protein kinases as central mediators of auxin-triggered phosphorylation across species. Genetic analysis connects this kinase to both auxin-triggered protein phosphorylation and rapid cellular response, thus identifying an ancient mechanism for fast auxin responses in the green lineage. AU - Kuhn, Andre AU - Roosjen, Mark AU - Mutte, Sumanth AU - Dubey, Shiv Mani AU - Carrillo Carrasco, Vanessa Polet AU - Boeren, Sjef AU - Monzer, Aline AU - Koehorst, Jasper AU - Kohchi, Takayuki AU - Nishihama, Ryuichi AU - Fendrych, Matyas AU - Sprakel, Joris AU - Friml, Jiří AU - Weijers, Dolf ID - 14826 IS - 1 JF - Cell KW - General Biochemistry KW - Genetics and Molecular Biology SN - 0092-8674 TI - RAF-like protein kinases mediate a deeply conserved, rapid auxin response VL - 187 ER - TY - JOUR AB - Bacteria divide by binary fission. The protein machine responsible for this process is the divisome, a transient assembly of more than 30 proteins in and on the surface of the cytoplasmic membrane. Together, they constrict the cell envelope and remodel the peptidoglycan layer to eventually split the cell into two. For Escherichia coli, most molecular players involved in this process have probably been identified, but obtaining the quantitative information needed for a mechanistic understanding can often not be achieved from experiments in vivo alone. Since the discovery of the Z-ring more than 30 years ago, in vitro reconstitution experiments have been crucial to shed light on molecular processes normally hidden in the complex environment of the living cell. In this review, we summarize how rebuilding the divisome from purified components – or at least parts of it - have been instrumental to obtain the detailed mechanistic understanding of the bacterial cell division machinery that we have today. AU - Radler, Philipp AU - Loose, Martin ID - 14834 IS - 1 JF - European Journal of Cell Biology KW - Cell Biology KW - General Medicine KW - Histology KW - Pathology and Forensic Medicine SN - 0171-9335 TI - A dynamic duo: Understanding the roles of FtsZ and FtsA for Escherichia coli cell division through in vitro approaches VL - 103 ER - TY - JOUR AB - The physical conditions giving rise to high escape fractions of ionizing radiation (LyC fesc) in star-forming galaxies – most likely protagonists of cosmic reionization – are not yet fully understood. Using the VLT/MUSE observations of ∼1400 Ly α emitters at 2.9 < z < 6.7, we compare stacked rest-frame UV spectra of candidates for LyC leakers and non-leakers selected based on their Ly α profiles. We find that the stacks of potential LyC leakers, i.e. galaxies with narrow, symmetric Ly α profiles with small peak separation, generally show (i) strong nebular O iii]λ1666, [Si iii]λ1883, and [C iii]λ1907 +C iii]λ1909 emission, indicating a high-ionization state of the interstellar medium (ISM); (ii) high equivalent widths of He iiλ1640 (∼1 − 3 Å), suggesting the presence of hard ionizing radiation fields; (iii) Si ii*λ1533 emission, revealing substantial amounts of neutral hydrogen off the line of sight; (iv) high C ivλλ1548,1550 to [C iii]λ1907 +C iii]λ1909 ratios (C iv/C iii] ≳0.75) , signalling the presence of low column density channels in the ISM. In contrast, the stacks with broad, asymmetric Ly α profiles with large peak separation show weak nebular emission lines, low He iiλ1640 equivalent widths (≲1 Å), and low C iv/C iii] (≲0.25), implying low-ionization states and high-neutral hydrogen column densities. Our results suggest that C iv/C iii] might be sensitive to the physical conditions that govern LyC photon escape, providing a promising tool for identification of ionizing sources among star-forming galaxies in the epoch of reionization. AU - Kramarenko, Ivan AU - Kerutt, J AU - Verhamme, A AU - Oesch, P A AU - Barrufet, L AU - Matthee, Jorryt J AU - Kusakabe, H AU - Goovaerts, I AU - Thai, T T ID - 14852 IS - 4 JF - Monthly Notices of the Royal Astronomical Society KW - Space and Planetary Science KW - Astronomy and Astrophysics SN - 0035-8711 TI - Linking UV spectral properties of MUSE Ly α emitters at z ≳ 3 to Lyman continuum escape VL - 527 ER - TY - JOUR AB - Elaborate sexual signals are thought to have evolved and be maintained to serve as honest indicators of signaller quality. One measure of quality is health, which can be affected by parasite infection. Cnemaspis mysoriensis is a diurnal gecko that is often infested with ectoparasites in the wild, and males of this species express visual (coloured gular patches) and chemical (femoral gland secretions) traits that receivers could assess during social interactions. In this paper, we tested whether ectoparasites affect individual health, and whether signal quality is an indicator of ectoparasite levels. In wild lizards, we found that ectoparasite level was negatively correlated with body condition in both sexes. Moreover, some characteristics of both visual and chemical traits in males were strongly associated with ectoparasite levels. Specifically, males with higher ectoparasite levels had yellow gular patches with lower brightness and chroma, and chemical secretions with a lower proportion of aromatic compounds. We then determined whether ectoparasite levels in males influence female behaviour. Using sequential choice trials, wherein females were provided with either the visual or the chemical signals of wild-caught males that varied in ectoparasite level, we found that only chemical secretions evoked an elevated female response towards less parasitised males. Simultaneous choice trials in which females were exposed to the chemical secretions from males that varied in parasite level further confirmed a preference for males with lower parasites loads. Overall, we find that although health (body condition) or ectoparasite load can be honestly advertised through multiple modalities, the parasite-mediated female response is exclusively driven by chemical signals. AU - Pal, Arka AU - Joshi, Mihir AU - Thaker, Maria ID - 14850 IS - 1 JF - Journal of Experimental Biology KW - Insect Science KW - Molecular Biology KW - Animal Science and Zoology KW - Aquatic Science KW - Physiology KW - Ecology KW - Evolution KW - Behavior and Systematics SN - 1477-9145 TI - Too much information? Males convey parasite levels using more signal modalities than females utilise VL - 227 ER -