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Science (New York, N.Y.) Mar 2023We introduce an interferometric MINFLUX microscope that records protein movements with up to 1.7 nanometer per millisecond spatiotemporal precision. Such precision has...
We introduce an interferometric MINFLUX microscope that records protein movements with up to 1.7 nanometer per millisecond spatiotemporal precision. Such precision has previously required attaching disproportionately large beads to the protein, but MINFLUX requires the detection of only about 20 photons from an approximately 1-nanometer-sized fluorophore. Therefore, we were able to study the stepping of the motor protein kinesin-1 on microtubules at up to physiological adenosine-5'-triphosphate (ATP) concentrations. We uncovered rotations of the stalk and the heads of load-free kinesin during stepping and showed that ATP is taken up with a single head bound to the microtubule and that ATP hydrolysis occurs when both heads are bound. Our results show that MINFLUX quantifies (sub)millisecond conformational changes of proteins with minimal disturbance.
Topics: Adenosine Triphosphate; Dyneins; Kinesins; Kinetics; Microtubules; Microscopy, Fluorescence; Fluorescent Dyes; Motion
PubMed: 36893244
DOI: 10.1126/science.ade2650 -
Current Opinion in Neurobiology Jun 2023Spike timing-dependent plasticity (STDP) is a bidirectional form of synaptic plasticity discovered about 30 years ago and based on the relative timing of pre- and... (Review)
Review
Spike timing-dependent plasticity (STDP) is a bidirectional form of synaptic plasticity discovered about 30 years ago and based on the relative timing of pre- and post-synaptic spiking activity with a millisecond precision. STDP is thought to be involved in the formation of memory but the millisecond-precision spike-timing required for STDP is difficult to reconcile with the much slower timescales of behavioral learning. This review therefore aims to expose and discuss recent findings about i) the multiple STDP learning rules at both excitatory and inhibitory synapses in vitro, ii) the contribution of STDP-like synaptic plasticity in the formation of memory in vivo and iii) the implementation of STDP rules in artificial neural networks and memristive devices.
Topics: Neurons; Neuronal Plasticity; Neural Networks, Computer; Synapses; Learning; Action Potentials
PubMed: 36924615
DOI: 10.1016/j.conb.2023.102707 -
The Veterinary Clinics of North... Jul 2023Extracorporeal shockwave therapy (ESWT) is a noninvasive treatment that involves the transcutaneous delivery of high-energy sound waves into tissue creating therapeutic... (Review)
Review
Extracorporeal shockwave therapy (ESWT) is a noninvasive treatment that involves the transcutaneous delivery of high-energy sound waves into tissue creating therapeutic effects. Shockwaves are nonlinear, high-pressure, high-velocity acoustic waves characterized by low tensile amplitude, short rise time to peak pressure, and a short duration (less than 10 milliseconds). ESWT has been shown to increase the expression of cytokines and growth factors leading to decreased inflammation, neovascularization, and cellular proliferation; activation of osteogenesis by osteoblast differentiation and then by increased proliferation; inhibition of cartilage degeneration and rebuilding of subchondral bone; and increased serotonin in the dorsal horn and descending inhibition of pain signals. Musculoskeletal conditions that can benefit from ESWT include osteoarthritis, tendinopathies, fracture/bone healing, and wound healing.
Topics: Animals; Extracorporeal Shockwave Therapy; High-Energy Shock Waves; Osteoarthritis; Fracture Healing; Bone and Bones
PubMed: 36964030
DOI: 10.1016/j.cvsm.2023.02.009 -
European Urology Jan 2023
Topics: Humans; Robotics; Equipment Design; Algorithms
PubMed: 36243542
DOI: 10.1016/j.eururo.2022.09.032 -
Cell Reports Oct 2019Recent rapid progress in the field of mechanobiology has been driven by novel emerging tools and methodologies and growing interest from different scientific... (Review)
Review
Recent rapid progress in the field of mechanobiology has been driven by novel emerging tools and methodologies and growing interest from different scientific disciplines. Specific progress has been made toward understanding how cell mechanics is linked to intracellular signaling and the regulation of gene expression in response to a variety of mechanical stimuli. There is a direct link between the mechanoreceptors at the cell surface and intracellular biochemical signaling, which in turn controls downstream effector molecules. Among the mechanoreceptors in the cell membrane, mechanosensitive (MS) ion channels are essential for the ultra-rapid (millisecond) transduction of mechanical stimuli into biologically relevant signals. The three decades of research on mechanosensitive channels resulted in the formulation of two basic principles of mechanosensitive channel gating: force-from-lipids and force-from-filament. In this review, we revisit the biophysical principles that underlie the innate force-sensing ability of mechanosensitive channels as contributors to the force-dependent evolution of life forms.
Topics: Animals; Biophysics; Cell Membrane; Humans; Ion Channels; Mechanoreceptors; Mechanotransduction, Cellular; Signal Transduction
PubMed: 31577940
DOI: 10.1016/j.celrep.2019.08.075 -
Nature Communications Apr 2023Two-photon, single-cell resolution optogenetics based on holographic light-targeting approaches enables the generation of precise spatiotemporal neuronal activity...
Two-photon, single-cell resolution optogenetics based on holographic light-targeting approaches enables the generation of precise spatiotemporal neuronal activity patterns and thus a broad range of experimental applications, such as high throughput connectivity mapping and probing neural codes for perception. Yet, current holographic approaches limit the resolution for tuning the relative spiking time of distinct cells to a few milliseconds, and the achievable number of targets to 100-200, depending on the working depth. To overcome these limitations and expand the capabilities of single-cell optogenetics, we introduce an ultra-fast sequential light targeting (FLiT) optical configuration based on the rapid switching of a temporally focused beam between holograms at kHz rates. We used FLiT to demonstrate two illumination protocols, termed hybrid- and cyclic-illumination, and achieve sub-millisecond control of sequential neuronal activation and high throughput multicell illumination in vitro (mouse organotypic and acute brain slices) and in vivo (zebrafish larvae and mice), while minimizing light-induced thermal rise. These approaches will be important for experiments that require rapid and precise cell stimulation with defined spatio-temporal activity patterns and optical control of large neuronal ensembles.
Topics: Mice; Animals; Zebrafish; Neurons; Photic Stimulation; Holography; Photons; Optogenetics; Light
PubMed: 37019891
DOI: 10.1038/s41467-023-37416-w -
Biopolymers Mar 2024The ribosome is a prototypical assembly that can be used to establish general principles and techniques for the study of biological molecular machines. Motivated by the... (Review)
Review
The ribosome is a prototypical assembly that can be used to establish general principles and techniques for the study of biological molecular machines. Motivated by the fact that the dynamics of every biomolecule is governed by an underlying energy landscape, there has been great interest to understand and quantify ribosome energetics. In the present review, we will focus on theoretical and computational strategies for probing the interactions that shape the energy landscape of the ribosome, with an emphasis on more recent studies of the elongation cycle. These efforts include the application of quantum mechanical methods for describing chemical kinetics, as well as classical descriptions to characterize slower (microsecond to millisecond) large-scale (10-100 Å) rearrangements, where motion is described in terms of diffusion across an energy landscape. Together, these studies provide broad insights into the factors that control a diverse range of dynamical processes in this assembly.
Topics: Molecular Dynamics Simulation; Ribosomes
PubMed: 38051695
DOI: 10.1002/bip.23570 -
International Journal of Molecular... Jun 2022The advancement of super-resolution imaging (SRI) relies on fluorescent proteins with novel photochromic properties. Using light, the reversibly switchable fluorescent... (Review)
Review
The advancement of super-resolution imaging (SRI) relies on fluorescent proteins with novel photochromic properties. Using light, the reversibly switchable fluorescent proteins (RSFPs) can be converted between bright and dark states for many photocycles and their emergence has inspired the invention of advanced SRI techniques. The general photoswitching mechanism involves the chromophore - isomerization and proton transfer for negative and positive RSFPs and hydration-dehydration for decoupled RSFPs. However, a detailed understanding of these processes on ultrafast timescales (femtosecond to millisecond) is lacking, which fundamentally hinders the further development of RSFPs. In this review, we summarize the current progress of utilizing various ultrafast electronic and vibrational spectroscopies, and time-resolved crystallography in investigating the on/off photoswitching pathways of RSFPs. We show that significant insights have been gained for some well-studied proteins, but the real-time "action" details regarding the bidirectional - isomerization, proton transfer, and intermediate states remain unclear for most systems, and many other relevant proteins have not been studied yet. We expect this review to lay the foundation and inspire more ultrafast studies on existing and future engineered RSFPs. The gained mechanistic insights will accelerate the rational development of RSFPs with enhanced two-way switching rate and efficiency, better photostability, higher brightness, and redder emission colors.
Topics: Crystallography; Green Fluorescent Proteins; Luminescent Proteins; Protons; Spectrum Analysis
PubMed: 35742900
DOI: 10.3390/ijms23126459