TY - JOUR AB - The coupling between Ca2+ channels and release sensors is a key factor defining the signaling properties of a synapse. However, the coupling nanotopography at many synapses remains unknown, and it is unclear how it changes during development. To address these questions, we examined coupling at the cerebellar inhibitory basket cell (BC)-Purkinje cell (PC) synapse. Biophysical analysis of transmission by paired recording and intracellular pipette perfusion revealed that the effects of exogenous Ca2+ chelators decreased during development, despite constant reliance of release on P/Q-type Ca2+ channels. Structural analysis by freeze-fracture replica labeling (FRL) and transmission electron microscopy (EM) indicated that presynaptic P/Q-type Ca2+ channels formed nanoclusters throughout development, whereas docked vesicles were only clustered at later developmental stages. Modeling suggested a developmental transformation from a more random to a more clustered coupling nanotopography. Thus, presynaptic signaling developmentally approaches a point-to-point configuration, optimizing speed, reliability, and energy efficiency of synaptic transmission. AU - Chen, JingJing AU - Kaufmann, Walter AU - Chen, Chong AU - Arai, Itaru AU - Kim, Olena AU - Shigemoto, Ryuichi AU - Jonas, Peter M ID - 14843 JF - Neuron SN - 0896-6273 TI - Developmental transformation of Ca2+ channel-vesicle nanotopography at a central GABAergic synapse ER - TY - THES AU - Chen, JingJing ID - 15101 SN - 2663 - 337X TI - Developmental transformation of nanodomain coupling between Ca2+ channels and release sensors at a central GABAergic synapse ER - TY - JOUR AB - Quantum computers are increasing in size and quality but are still very noisy. Error mitigation extends the size of the quantum circuits that noisy devices can meaningfully execute. However, state-of-the-art error mitigation methods are hard to implement and the limited qubit connectivity in superconducting qubit devices restricts most applications to the hardware's native topology. Here we show a quantum approximate optimization algorithm (QAOA) on nonplanar random regular graphs with up to 40 nodes enabled by a machine learning-based error mitigation. We use a swap network with careful decision-variable-to-qubit mapping and a feed-forward neural network to optimize a depth-two QAOA on up to 40 qubits. We observe a meaningful parameter optimization for the largest graph which requires running quantum circuits with 958 two-qubit gates. Our paper emphasizes the need to mitigate samples, and not only expectation values, in quantum approximate optimization. These results are a step towards executing quantum approximate optimization at a scale that is not classically simulable. Reaching such system sizes is key to properly understanding the true potential of heuristic algorithms like QAOA. AU - Sack, Stefan AU - Egger, Daniel J. ID - 15122 IS - 1 JF - Physical Review Research SN - 2643-1564 TI - Large-scale quantum approximate optimization on nonplanar graphs with machine learning noise mitigation VL - 6 ER - TY - JOUR AB - Cell division in all domains of life requires the orchestration of many proteins, but in Archaea most of the machinery remains poorly characterized. Here we investigate the FtsZ-based cell division mechanism in Haloferax volcanii and find proteins containing photosynthetic reaction centre (PRC) barrel domains that play an essential role in archaeal cell division. We rename these proteins cell division protein B 1 (CdpB1) and CdpB2. Depletions and deletions in their respective genes cause severe cell division defects, generating drastically enlarged cells. Fluorescence microscopy of tagged FtsZ1, FtsZ2 and SepF in CdpB1 and CdpB2 mutant strains revealed an unusually disordered divisome that is not organized into a distinct ring-like structure. Biochemical analysis shows that SepF forms a tripartite complex with CdpB1/2 and crystal structures suggest that these two proteins might form filaments, possibly aligning SepF and the FtsZ2 ring during cell division. Overall our results indicate that PRC-domain proteins play essential roles in FtsZ-based cell division in Archaea. AU - Nußbaum, Phillip AU - Kureisaite-Ciziene, Danguole AU - Bellini, Dom AU - Van Der Does, Chris AU - Kojic, Marko AU - Taib, Najwa AU - Yeates, Anna AU - Tourte, Maxime AU - Gribaldo, Simonetta AU - Loose, Martin AU - Löwe, Jan AU - Albers, Sonja Verena ID - 15118 IS - 3 JF - Nature Microbiology TI - Proteins containing photosynthetic reaction centre domains modulate FtsZ-based archaeal cell division VL - 9 ER - TY - JOUR AB - In this paper we consider an SPDE where the leading term is a second order operator with periodic boundary conditions, coefficients which are measurable in (t,ω) , and Hölder continuous in space. Assuming stochastic parabolicity conditions, we prove Lp((0,T)×Ω,tκdt;Hσ,q(Td)) -estimates. The main novelty is that we do not require p=q . Moreover, we allow arbitrary σ∈R and weights in time. Such mixed regularity estimates play a crucial role in applications to nonlinear SPDEs which is clear from our previous work. To prove our main results we develop a general perturbation theory for SPDEs. Moreover, we prove a new result on pointwise multiplication in spaces with fractional smoothness. AU - Agresti, Antonio AU - Veraar, Mark ID - 15119 IS - 1 JF - Annales de l'institut Henri Poincare Probability and Statistics SN - 0246-0203 TI - Stochastic maximal Lp(Lq)-regularity for second order systems with periodic boundary conditions VL - 60 ER -