The methods used to measure torque can be further divided into two more categories: reaction or in-line. Torque Measurement Techniques – A Timeline, Real-Time Wireless Conveyor Diagnostic System, Wireless Coupled Flange Torque Transducer. To directly investigate the energetics of the B-Z transition and the properties of strand-separated DNA, we investigated sequences that are expected to form Z-DNA or strand-separated DNA at low torques. In this work, we report torque-twist relationships obtained by linearly ramping the twist clamp setpoint up and down to sample twist values during unwinding and rewinding. This includes all methods involving measurement either of the strain resulting from shaft torsion on its surface or of the shaft's torsion angle. While untainted by slip ring technology shortcomings, they had some of their own. The meter calculates the power input by … For the static implementation (Fig. Ensure that torque is set between every measurement in the settable torque wrench to simulate actual usage between repeated readings. We observe a torque “overshoot” at the beginning of this buckling transition (Fig. Strain gage technology (DMS) is a powerful solution for measurements on rotating shafts, and also for long-term dynamic and static measurements. The noise floor of a typical balanced bridge resistance measurement is less than 5mΩ/500Ω. If the rotational probe is also used as a handle for applying tension, its volume cannot be reduced arbitrarily without sacrificing accessible force ranges. performed research; F.C.O., L.E.F., and Z.B. Cooperativity in the model arises because junctions between differing states are assessed a free energy penalty J. Parts may not be assembled securely enough for the unit to function properly or threads may be stripped because the torque was too high, causing the unit to fail. The end results are measurement sensors and transducers you can trust, and we can be proud of. designed research; F.C.O. Torque measurement system can also be used for the control of rotary oscillations attributed to changes in the dynamics of torque value in time domain and to the fluctuations in the resistance level. 2 and Table S2). This system included an on-board signal conditioner/radio transmitter that modulated the strain gage bridge output to a radio frequency signal. Compromises between the conflicting requirements of torque probes and force handles have been a factor in the poor torque resolution of some previous methods, necessitating hours or even days (22) of noise-averaging data collection to determine torque-twist relationships. Torque can be divided into two major categories, either static or dynamic. SensorData’s BT400 series is by large today’s state of the art in digital telemetry. Understanding the type of torque to be measured, as well as the different types of torque sensors that are available, will have a profound impact on the accuracy of the resulting data, as well as the cost of the measurement. Comparison of unwinding (fine lines) with averaged rewinding curves (bold lines) shows reduced hysteresis in Z22sp. However,it has been shown that the SOTs quantified by ST-FMR and SHH techniques agree within the experimental accuracy for several systems [36] [37] [38] [39]. Our measurements of significant helicity and relatively high rigidity for L-DNA, together with a reduction in the coexistence torque at high ionic strength, are difficult to reconcile with a model in which L-DNA consists solely of strand-separated DNA. Red and yellow lines show transition model fits. The methods used to measure torque can be further divided into two more categories, either reaction or in-line. We have investigated sequence-dependent structural transitions using an extension of the rotor bead tracking (RBT) assay (11, 25) that allows torque to be measured as a function of imposed twist (Fig. Extrapolating from this region, we obtain a difference in helicity between B-DNA and L-DNA at zero torque, Δθ0,L = 1 rad/bp. Averaged traces are each based on three independent measurements. Hybrid destabilization due to individual basepair mismatches has been extensively characterized (34), but little is known about the structure of long mismatched stretches or the cooperativity of mismatched strand–strand interactions. These shortcomings opened the door for the development of rotary transformers. This assay lacks versatility because of its baroque geometry and inability to impose fixed twist, and it has not been widely applied for torque measurements beyond its initial introduction. Se-Jin Lee and Emily Germain-Lee explain a way to preserve bone and muscle mass during spaceflight. Torsional response of GC repeats: Z-DNA formation. The sequence dependence of stress-induced destabilization (2) has been hypothesized to affect the specific localization of replication initiation (3, 4) and the variable response of transcriptional promoters (5). Modern strain gage technology allows for sensors to be smaller, stiffer and faster than ever before, the very attributes SensorData capitalizes on. Measuring torque accurately, particularly in rotating shafts, can often be challenging, but new technology is providing a better solution, says Mark Ingham of Sensor Technology. This guide will help you develop your own torque measurement program. The HBMrange includes several forms of force transducers and load cells that can measure reaction force by means of a lever arm (figure 2). S1B and Table S1). Piezoelectric reaction torque sensors offer convincing features such as exceptional overload … (A) Templates containing 50 bp (yellow, Z50) or 22 bp (green, Z22) GC repeat SOIs were assayed in PBS under 1.6 pN. In contrast to B-Z transitions in GC repeats, the critical torque for disruption of Bub100 is not significantly affected by increasing the ionic strength (Fig. 2 A and B and SI Text) to verify our physical understanding and extract structural, mechanical, and thermodynamic parameters for alternative structural forms. Online ISSN 1091-6490. For the shorter Z22 construct, the plateau is absent and the torque-twist diagram resembles the two-state behavior seen in RNA hairpin unzipping experiments (17). Under moderate or high salt conditions, the unwinding and rewinding curves show hysteresis, implying that B-Z transitions are not in equilibrium on the time scale of the experiment (Fig. The disadvantage of its correct solution by experimental methods is substantially limited by the need … Torque measurement is required when the product is held together by nuts and bolts. Torque basics, Hooke's law Torque is force around a point or axis — a twisting force — and is calculated by multiplying an applied force by the distance through which the force works. Z22 and Z50 display changes in helicity Δθ0 = -0.9 rad/bp, which is smaller than the expected Δθ0 = -1.12 rad/bp based on gel electrophoresis assays (10) and X-ray crystal structures of Z-DNA (7). *This Direct Submission article had a prearranged editor. In addition to strand separation, superhelical tension may also be released by the formation of Z-DNA, a left-handed double-helical structure (7, 8). S1 B and C and Table S1), including a decrease in the critical torque for the B-L transition by approximately 15% at high ionic strength (Fig. In a plot of torque as a function of twist (Fig. 2), consistent with bulk kinetics: at a constant supercoiling density of σ = -0.05, the half time for the B-Z transition of d(GC)16 was measured to be approximately 20 min (38). Data analysis, models for fitting and statistics are described in SI Text. Shelby Township, MI 48315 - USA. In English units, the force is measured in pounds or ounces, and the distance in feet or inches. The importance of this problem is increased by an order in terms of unsteady loads (random, impulsive, alternating, etc.). Direction of force: tensile and/or compressive force 4. This transition between distinct structural states within T100 suggests that there are weak but significant strand–strand interactions in the absence of torque, which are disrupted when torque is applied. Manufacturers making use of these developments in digital telemetry introduced several look-alikes that were almost identical in form and in inherent limitations as well. Torque wrenches must be tested on a routine basis using torque measurement devices, including torque analyzers and sensors. Models of biological site-specific responses to supercoiling must account for the interplay between multiple available underwound structural forms (43). The stiffness and Δθ0 values are consistent with a model in which high salt mitigates any end effects due to B/Z junctions, in addition to stabilizing Z-DNA. Mismatch bubbles of the type d(pGpApCpT)n•d(pGpApCpT)n serve as a synthetic origin of DNA replication and enable helicase loading, whereas canonical double-stranded DNA does not (33). Torsional stress and local denaturation in supercoiled DNA, Energetics of the strand separation transition in superhelical DNA, Susceptibility to superhelically driven DNA duplex destabilization: A highly conserved property of yeast replication origins, Stable DNA unwinding, not “breathing,” accounts for single-strand-specific nuclease hypersensitivity of specific A+T-rich sequences, Genomic transcriptional response to loss of chromosomal supercoiling in Escherichia coli, Oscillations in supercoiling drive circadian gene expression in cyanobacteria, Molecular-structure of a left-handed double helical DNA fragment at atomic resolution, Flipping of cloned d(pCpG)n. d(pCpG)n DNA sequences from right- to left-handed helical structure by salt, Co(III), or negative supercoiling, Negatively supercoiled plasmids contain left-handed Z-DNA segments as detected by specific antibody binding, Structural transitions and elasticity from torque measurements on DNA, Magnetic torque tweezers: Measuring torsional stiffness in DNA and RecA-DNA filaments, Stretched and overwound DNA forms a Pauling-like structure with exposed bases, Structural transitions of a twisted and stretched DNA molecule, Structural transitions in DNA driven by external force and torque, Ten years of tension: Single-molecule DNA mechanics, Determination of thermodynamics and kinetics of RNA reactions by force, Unzipping DNA with optical tweezers: High sequence sensitivity and force flips, Single-molecule derivation of salt dependent base-pair free energies in DNA, Direct measurement of the full, sequence-dependent folding landscape of a nucleic acid, Magnetic tweezers measurement of single molecule torque, Soft magnetic tweezers: A proof of principle, Abrupt buckling transition observed during the plectoneme formation of individual DNA molecules, Nanofabricated quartz cylinders for angular trapping: DNA supercoiling torque detection, Energetics at the DNA supercoiling transition, The free energy, enthalpy and entropy of native and of partially denatured closed circular DNA, Torque and dynamics of linking number relaxation in stretched supercoiled DNA, Minute negative superhelicity is sufficient to induce the B-Z transition in the presence of low tension, Molecular mechanisms for the B-Z transition in the example of poly[d(G-C)center dot d(G-C)] polymers. The base pair geometry of GACT mismatch bubbles, in which pyrimidine bases oppose purines, may help conserve a Watson–Crick-like structure with a reduced number of hydrogen bonds in comparison with complementary B-DNA. Individual unwinding curves (fine lines) were variable and differed from the consistent behavior of rewinding curves (averaged, bold lines). In subsequent analysis of the B-Z transition, we use rewinding curves as approximations for equilibrium torque-twist relationships. We would like to thank J. Berger, J. Marko, A. Spakowitz, A. Vologodskii, A. Basu, P. Lebel, M. Elting, P. Pease, and the Bryant and Berger groups for useful discussions and comments on the manuscript. 2B). The sequence-dependent torsional response of paired and mispaired duplexes is also of direct relevance to understanding and designing the mechanical behavior of DNA nanostructures. The "damp-like" torque and "field-like" torque can be measured by following techniques: 1) from measurement of anisotropy field; 2) by 2f-lockin technique; 3) from ST-FMR measurements . The following three imaging buffers were used for rotor bead tracking experiments. Less tolerance to thrust and bending moment loads in addition to requiring some sophisticated AC carrier excitation and signal conditioning, led manufacturers to find yet another way to overcome these hindrances. The fluorescent rotor bead (RB, green) is attached to the side of the DNA molecule via biotin:neutravidin interactions. Here, we use our torque-measurement techniques to investi-gate specific states that can contribute to localized sequence-dependent responses to negative supercoiling. Initiation of the B-L transition occurs at low twist densities near σ = -0.02, reflecting local formation of alternative structures under supercoiling conditions that are biologically accessible. The preferred form of excitation of this system was yet another on-board battery pack. By the late 80’s microprocessor and surface mount technologies has already made tremendous strides leading to the miniaturization of circuitries and the development of several families of micro-chips. A nuclear magnetic resonance study of T.T pairing at neutral pH and C.C pairing at acidic pH in dodecanucleotide duplexes, X-ray structure of a DNA hairpin molecule, A theoretical study of formation of DNA noncanonical structures under negative superhelical stress, Promoter unwinding and promoter clearance by RNA polymerase: Detection by single-molecule DNA nanomanipulation, Homologous pairing in stretched supercoiled DNA, Underwound DNA under tension: Structure, elasticity, and sequence-dependent behaviors, Folding DNA into twisted and curved nanoscale shapes, Proceedings of the National Academy of Sciences, Earth, Atmospheric, and Planetary Sciences, www.pnas.org/lookup/suppl/doi:10.1073/pnas.1113532109/-/DCSupplemental, Journal Club: Model captures how polarization emerges on social media during political campaigns, News Feature: To understand the plight of insects, entomologists look to the past, Science and Culture: Astronomer-turned-filmmaker strives to ignite an interest in space, Protecting against spaceflight-induced muscle and bone loss. (B) Response of 100 bp (dark green, Bub100) and 50 bp (light green, Bub50) d(pGpApCpT)n•d(pGpApCpT)n SOIs assayed in PBS under 10 pN of tension. After saturating this transition, a second linear region reflects the twist elasticity of L-DNA (Fig. The coexistence plateau occurs at τZ = -3 pNnm in PBS. To investigate Z-DNA formation, we used SOIs containing either a 50 bp or a 22 bp GC repeat. 4). All the other needed intelligence was mounted on board the sensor. Using a U2B force tran… Several assays have previously been described for measuring torque in single stretched DNA molecules (11, 12, 21⇓–23). Measuring torque with angle sensors. Δθ0,L and effective twist persistence length Pt,eff,L of the L state are displayed ± SEM, based on linear fits to the data spanning −15 and -20 pNnm. 4B). 1D) is substantially larger than previous estimates of a few bp for strand-separated DNA (27, 28). The twist persistence length of L-DNA Pt,eff = 20–30 bp (Fig. This method allows the torque sensor to be placed as close as possible to the torque of interest and avoid possible errors in the … Torque is measured by observing the angular velocity of a submicron bead attached to the side of the DNA. 2A). Author contributions: F.C.O., L.E.F., and Z.B. 1D and Table S1). To investigate these properties, we tested the torsional response of DNA mismatch bubbles. How to Use Torque Analyzers and Sensors. It uses the well established Blue Tooth platform, which makes it immune to either emi or emf. Low salt: 0.5 mg/mL BSA, 10 mM Tris, pH 7.4. How to Measure Torque On an Existing Shaft. The rotor will spin to relieve this twist, but a fixed twist condition can be imposed by rotating the magnets to counteract this relaxation, using a “twist clamp” feedback algorithm. L-DNA has been proposed to be partially or entirely composed of strand-separated DNA, and thermodynamic models of supercoiling-induced strand separation depend on knowledge of the mechanical properties of strand-separated DNA. 50207 Hayes Road As shown from the diagram below, slip ring technology was the earliest method of transmitting power to and signal from a rotating shaft to a stationary housing. Torque-twist plots of Z50 and Z22 collected at 1.6 pN of tension show clear transitions to a second state upon application of negative torque (Fig. The example vehicle is a four wheel drive (4WD) agricultural tractor - but it is proposed that the same measurement techniques … 3A). In biological contexts, trans-acting factors can bias the equilibrium between available structural transitions, and it should be emphasized that stress-induced destabilization of the duplex (1) is important even when spontaneous strand separation is absent: Linking number deficits may be absorbed by stabilizing a bubble upon protein binding (44) or invasion of a homologous strand to form a D loop (45), without ever forming an open bubble as a stable intermediate in this transaction. These constructs are readily prepared using standard molecular biology techniques, as described in SI Text. Accurate quantitative models of sequence-dependent structural transitions are needed to explain sophisticated cellular functions such as supercoiling-dependent regulation of gene expression profiles (5, 6). Mismatch sequences were chosen as low-stability substrates to investigate strand separation and characterize the mechanical properties of strand-separated DNA. B-DNA becomes unstable under superhelical stress and is able to adopt a wide range of alternative conformations including strand-separated DNA and Z-DNA. Torque ripple is periodic disturbances in torque, and it results in noise vibration. Consultants & Experts with 25+ years of Innovative Engineering and manufacturing force & torque measurement sensors and systems. GACT bubbles seem to adopt a B-DNA-like structure (Fig. S2). Image credit: José Francisco Salgado (artist). Some of these inherent limitations were; antennas were limited to a few select sizes, cables from the signal conditioning receiver to data acquisition systems were also limited to certain lengths, proximity to steel structures affect readings accuracy, and emitted emi (electro-magnetic interference) were sometimes more than allowed by government. Design 3. Long stretches of mismatched DNA have been used to investigate in vitro DNA helicase loading. All methods employ at least one microparticle as a handle for applying pN-scale tensions to the DNA using optical or magnetic forces. 3A and Table S2). Measurement of torque and angle produced by power tools. Image credit: Joyce Gross (University of California, Berkeley). A model for cooperative structural transitions in homogeneous sequences under torque. By saturating the transition, the extrapolated change in helicity per base pair Δθ0,L can be obtained. Figure 2. Z-DNA formation is cooperative (9, 10, 30), which may be explained by a high nucleation penalty due to the formation of unfavorable conformations at junctions between Z-DNA and B-DNA (10, 30, 31). (A) Torque-twist curve for d(pT)100•d(pT)100 SOI (T100) and negative control DNA (gray tones) in PBS, together with fits to the cooperative transition model (light blue and green lines). Unlike angular optical trap measurements (23), the torque measurements reported here do not include simultaneous high-resolution extension measurements, which may be incorporated in future improvements to the assays. (D) L-DNA helicity and elasticity vary with tension. Feedback enhanced rotor bead tracking assay and torsional response of control DNA. Plumbing a variety of historical data could offer important insights into trends in insect declines. (A) Fits are shown for Z50, Z22, Bub100, and T100, demonstrating the range of behaviors explained by the model described in SI Text. In contrast to poly(dT) bubbles, torsionally relaxed GACT mismatch bubbles are not detectably softer than B-DNA. 2C). S4). Results and traces are saved and transferred to remote databases. technique. Propensity for each of these structural transitions is strongly sequence-dependent; Z-DNA formation is favored by GC repeats and more generally by alternation of purines and pyrimidines (9, 10). The newest kid on the block was the digital telemetry system. Its transceiver can be placed anywhere from 0.25”- 30.00’ instead of the tethered 0.25” of available models, and is not affected by proximity to steel structures. (B) Overlay of individual unwinding (dark blue) and rewinding (light blue) experiments for Z50 under low salt conditions (Upper), showing reversibility. Torque analyzers and sensors must themselves be tested as well, using torque calibration equipment including precisely engineered dead weights. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. However, there’s a scope of uncertainties and errors in measurement when it … Forces measured during unzipping of long double-stranded DNAs show clear sequence-dependent features that can largely be reproduced using calculations based on the primary sequence and assuming thermal equilibrium (18); recent measurements have been used to determine salt-dependent base pair free energies (19). Our theory and methods establish a framework for understanding the torsional response of arbitrary sequences, which ultimately should be predictable from reductionist measurements on simple sequences such as those described here. L-DNA has a torsional persistence length significantly greater than either our estimates or previous estimates for strand-separated DNA, is stabilized rather than destabilized by high ionic strength, and is confirmed to be highly helical. DNA twist and rotor angular velocities were obtained from raw traces (insert) showing the cumulative angles of the magnets (orange trace) and RB (green trace) as a function of time. The task of measuring, monitoring and recording of the torque, mechanical stress and capacity is relevant for most transmissions of the process and transport machines. The corresponding region of DNA phase space has been labeled “L-DNA” (16) solely to recognize this overall handedness. All of these measurements are consistent with the “mixed state” hypothesis. Mb angle can be introduced by rotating the torque measurement techniques unexpected posttransition softening for Z50 (.... All buffers also contained 5 mM EDTA and an oxygen scavenging system low! Of Bub100 is insensitive to increased ionic strength will help you develop own... ( Fig unexpected posttransition softening for Z50 show a negative torque induce Z-DNA formation in GC tracts (,. 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Brush-Ring wear, frequent maintenance was required ; by a single statistical mechanical model cooperative! Lee and Emily Germain-Lee explain a way to preserve bone and muscle mass during.... Analysis of the DNA double helix are essential for accessing genomic information stress and is able to a. We have further discovered ionic strength effects ( Fig, a force and torque sensors, it 's still to... Guide will help you develop your own torque measurement techniques under superhelical stress ( 1 ) and display... Access option, a reversible transition occurs to a number of problems moderate. Are consistent with the “ mixed state ” hypothesis tested the torsional of!