Power output from a flight muscle of the bumblebee Bombus terrestris. I. Some features of the dorso-ventral flight muscle

1997 ◽  
Vol 200 (8) ◽  
pp. 1215-1226 ◽  
Author(s):  
R Josephson ◽  
C Ellington
Keyword(s):  
Flight Muscle ◽  
Bombus Terrestris ◽  
Low Frequency ◽  
Muscle Strain ◽  
Optimal Length ◽  
Tetanic Force ◽  
Tethered Flight ◽  
Wing Stroke ◽  
Tetanic Tension

1. Isometric contractions from the asynchronous dorso-ventral flight muscle of the bumblebee Bombus terrestris were slow and rather weak. The twitch duration (onset to 50 % relaxation) was approximately 300 ms at 30 °C and 170 ms at 40 °C. The maximum tetanic tension was approximately 40 kN m-2; the ratio of twitch force to tetanic force was approximately 0.2. 2. The unstimulated muscle was quite resistant to stretch, with a low-frequency stiffness of 730 kN m-2 at muscle lengths close to that of the muscle in vivo. The length­tension curve for active tetanic tension (that is the increase in tension above the passive level during stimulation) was very narrow, with a half-width equal to only 17 % of the optimal length. 3. The muscle strain during tethered flight was approximately 2 % peak-to-peak, occasionally reaching 3 %. Strain amplitude increased with wing stroke frequency. The thoracic vibration frequency of escape buzzing, during which the wings are not extended but are folded over the abdomen, was approximately twice that of tethered flight but the muscle strain was similar to that of flight.

scholarly journals In vivo length oscillations of indirect flight muscles in the fruit fly Drosophila virilis.

1996 ◽  
Vol 199 (12) ◽  
pp. 2767-2774 ◽  
Author(s):  
W P Chan ◽  
M H Dickinson
Keyword(s):  
High Speed ◽  
Fruit Fly ◽  
Drosophila Virilis ◽  
Peak Strain ◽  
Muscle Strain ◽  
Tethered Flight ◽  
Biophysical Studies ◽  
Order Of Magnitude ◽  
Flight Muscles

We have used high-speed video microscopy to measure in vivo length oscillations of the indirect flight muscles of the fruit fly Drosophila virilis during tethered flight. The changes in muscle strain were measured by tracking the deformation of the thoracic exoskeleton at the origin and insertion of both the dorsal longitudinal (DLM) and the dorsal ventral (DVM) muscles. The mean peak-to-peak strain amplitudes were found to be 3.5% for the DLMs and 3.3% for the DVMs, although the strain amplitude within individual cycles ranged from 2 to 5%. These values are consistent with the small number of previous measurements of indirect flight muscle strain in other insects, but almost an order of magnitude greater than the strain amplitudes used in most biophysical studies of skinned Drosophila fibers. The results suggest that serial compliance within this sarcomere would need to relieve approximately 70% of the total strain in order for individual crossbridges to remain attached throughout a complete contraction-extension cycle.

Effects of fatigue on the length-tetanic force relationship of the rat diaphragm

1993 ◽  
Vol 74 (1) ◽  
pp. 326-332 ◽  
Author(s):  
A. P. Gauthier ◽  
R. E. Faltus ◽  
P. T. Macklem ◽  
F. Bellemare
Keyword(s):  
High Frequency ◽  
Force Production ◽  
High Frequency Stimulation ◽  
Control Force ◽  
Optimal Length ◽  
Tetanic Force ◽  
Wide Range ◽  
Force Relationship

It has been established that the in vivo operating length of the diaphragm corresponds to a wide range of the ascending limb of its length-tetanic force relationship. To investigate the length-dependent effects of fatigue on maximum force production, we constructed length-tetanic force relationships of rat costal diaphragm strips in vitro before and after fatigue induced by repetitive supramaximal electrical field stimulations at optimal length. Two levels of fatigue were studied (i.e., force reductions of 40 and 65% at optimal length). Results indicate that fatigue, when evaluated with high-frequency stimulations, causes a proportionately larger decrease in tetanic force at short muscle lengths as seen by a smaller control force-to-fatigue force ratio and an apparent shift in the length at which active force is zero. A possible explanation for the results obtained is failure of propagation of membrane depolarization into the t-tubule system at short muscle lengths, which is aggravated by fatigue evaluated by high-frequency stimulation.

scholarly journals Changes in electromyographic activity, mechanical power, and relaxation rates following inspiratory ribcage muscle fatigue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Antonio Sarmento ◽  
Guilherme Fregonezi ◽  
Maria Lira ◽  
Layana Marques ◽  
Francesca Pennati ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Low Frequency ◽  
Mechanical Power ◽  
Electromyographic Activity ◽  
Median Frequency ◽  
Relaxation Rates ◽  
Shortening Velocity ◽  
Inspiratory Muscles ◽  
Underlying Mechanisms

AbstractMuscle fatigue is a complex phenomenon enclosing various mechanisms. Despite technological advances, these mechanisms are still not fully understood in vivo. Here, simultaneous measurements of pressure, volume, and ribcage inspiratory muscle activity were performed non-invasively during fatigue (inspiratory threshold valve set at 70% of maximal inspiratory pressure) and recovery to verify if inspiratory ribcage muscle fatigue (1) leads to slowing of contraction and relaxation properties of ribcage muscles and (2) alters median frequency and high-to-low frequency ratio (H/L). During the fatigue protocol, sternocleidomastoid showed the fastest decrease in median frequency and slowest decrease in H/L. Fatigue was also characterized by a reduction in the relative power of the high-frequency and increase of the low-frequency. During recovery, changes in mechanical power were due to changes in shortening velocity with long-lasting reduction in pressure generation, and slowing of relaxation [i.e., tau (τ), half-relaxation time (½RT), and maximum relaxation rate (MRR)] was observed with no significant changes in contractile properties. Recovery of median frequency was faster than H/L, and relaxation rates correlated with shortening velocity and mechanical power of inspiratory ribcage muscles; however, with different time courses. Time constant of the inspiratory ribcage muscles during fatigue and recovery is not uniform (i.e., different inspiratory muscles may have different underlying mechanisms of fatigue), and MRR, ½RT, and τ are not only useful predictors of inspiratory ribcage muscle recovery but may also share common underlying mechanisms with shortening velocity.

scholarly journals Olfactory coding in the antennal lobe of the bumble bee Bombus terrestris

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcel Mertes ◽  
Julie Carcaud ◽  
Jean-Christophe Sandoz
Keyword(s):  
Honey Bees ◽  
Antennal Lobe ◽  
Bombus Terrestris ◽  
Bumble Bees ◽  
Foraging Strategies ◽  
Bumble Bee ◽  
Carbon Chain Length ◽  
Olfactory Coding ◽  
Major Transitions

AbstractSociality is classified as one of the major transitions in evolution, with the largest number of eusocial species found in the insect order Hymenoptera, including the Apini (honey bees) and the Bombini (bumble bees). Bumble bees and honey bees not only differ in their social organization and foraging strategies, but comparative analyses of their genomes demonstrated that bumble bees have a slightly less diverse family of olfactory receptors than honey bees, suggesting that their olfactory abilities have adapted to different social and/or ecological conditions. However, unfortunately, no precise comparison of olfactory coding has been performed so far between honey bees and bumble bees, and little is known about the rules underlying olfactory coding in the bumble bee brain. In this study, we used in vivo calcium imaging to study olfactory coding of a panel of floral odorants in the antennal lobe of the bumble bee Bombus terrestris. Our results show that odorants induce reproducible neuronal activity in the bumble bee antennal lobe. Each odorant evokes a different glomerular activity pattern revealing this molecule’s chemical structure, i.e. its carbon chain length and functional group. In addition, pairwise similarity among odor representations are conserved in bumble bees and honey bees. This study thus suggests that bumble bees, like honey bees, are equipped to respond to odorants according to their chemical features.

The Ets-related transcription factor PU.1 immortalizes erythroblasts

1993 ◽  
Vol 13 (9) ◽  
pp. 5670-5678
Author(s):  
S Schuetze ◽  
P E Stenberg ◽  
D Kabat
Keyword(s):  
Bone Marrow ◽  
Transcription Factor ◽  
Cell Lines ◽  
Cultured Cells ◽  
Low Frequency ◽  
In Vivo Studies ◽  
Bone Marrow Cultures ◽  
Clonal Cell Lines ◽  
Related Transcription Factor

In vivo studies of Friend virus erythroleukemia have implied that proviral integrations adjacent to the gene for the Ets-related transcription factor PU.1 may inhibit the commitment of erythroblasts to differentiate and cause their capability for indefinite transplantation (C. Spiro, B. Gliniak, and D. Kabat, J. Virol. 62:4129-4135, 1988; R. Paul, S. Schuetze, S. L. Kozak, C. Kozak, and D. Kabat, J. Virol. 65:464-467, 1991). To test this hypothesis, we ligated PU.1 cDNA into a retroviral vector and studied its effects on cultured cells. Infection of fibroblasts with PU.1-encoding retrovirus resulted in PU.1 synthesis followed by nuclear pyknosis, cell rounding, and degeneration. In contrast, in long-term bone marrow cultures, erythroblasts were efficiently and rapidly immortalized. The resulting cell lines were polyclonal populations that contained PU.1, were morphologically blast-like, required erythropoietin and bone marrow stromal cells for survival and proliferation, and spontaneously differentiated at low frequency to synthesize hemoglobin. After 9 months in culture, erythroblasts became stroma independent, and they then grew as clonal cell lines. We conclude that PU.1 perturbs the pathway(s) that controls potential for indefinite proliferation and that it can be used to generate permanent erythroblast cell lines.

Dynamics of in vivo power output and efficiency of Nasonia asynchronous flight muscle

2006 ◽  
Vol 124 (1) ◽  
pp. 93-107 ◽  
Author(s):  
Fritz-Olaf Lehmann ◽  
Nicole Heymann
Keyword(s):  
Power Output ◽  
Flight Muscle

scholarly journals Signal-to-noise ratio in the membrane potential of the owl's auditory coincidence detectors

2012 ◽  
Vol 108 (10) ◽  
pp. 2837-2845 ◽  
Author(s):  
Go Ashida ◽  
Kazuo Funabiki ◽  
Paula T. Kuokkanen ◽  
Richard Kempter ◽  
Catherine E. Carr
Keyword(s):  
Neural Circuit ◽  
Signal To Noise Ratio ◽  
Phase Locking ◽  
Low Frequency ◽  
Membrane Potentials ◽  
Signal To Noise ◽  
Theoretical Predictions ◽  
Noise Ratio ◽  
Band Limited

Owls use interaural time differences (ITDs) to locate a sound source. They compute ITD in a specialized neural circuit that consists of axonal delay lines from the cochlear nucleus magnocellularis (NM) and coincidence detectors in the nucleus laminaris (NL). Recent physiological recordings have shown that tonal stimuli induce oscillatory membrane potentials in NL neurons (Funabiki K, Ashida G, Konishi M. J Neurosci 31: 15245–15256, 2011). The amplitude of these oscillations varies with ITD and is strongly correlated to the firing rate. The oscillation, termed the sound analog potential, has the same frequency as the stimulus tone and is presumed to originate from phase-locked synaptic inputs from NM fibers. To investigate how these oscillatory membrane potentials are generated, we applied recently developed signal-to-noise ratio (SNR) analysis techniques (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274–2290, 2010) to the intracellular waveforms obtained in vivo. Our theoretical prediction of the band-limited SNRs agreed with experimental data for mid- to high-frequency (>2 kHz) NL neurons. For low-frequency (≤2 kHz) NL neurons, however, measured SNRs were lower than theoretical predictions. These results suggest that the number of independent NM fibers converging onto each NL neuron and/or the population-averaged degree of phase-locking of the NM fibers could be significantly smaller in the low-frequency NL region than estimated for higher best-frequency NL.

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