The contractile protein myosin
This content will become publicly available on October 19, 2024
Predicting the effects of spatiotemporal modifications of muscle activation on the tentacle extension in squid
Squid use eight arms and two slender tentacles to capture prey. The muscular stalks of the tentacles are elongated approximately 80% in 20–40 ms towards the prey, which is adhered to the terminal clubs by arrays of suckers. Using a previously developed forward dynamics model of the extension of the tentacles of the squid
- Award ID(s):
- 1755231
- NSF-PAR ID:
- 10475194
- Publisher / Repository:
- https://doi.org/10.3389/fbioe.2023.1193409
- Date Published:
- Journal Name:
- Frontiers in Bioengineering and Biotechnology
- Volume:
- 11
- ISSN:
- 2296-4185
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract II is ubiquitous in muscle. It is widely accepted that animals express tissue‐specific myosin isoforms that differ in amino acid sequence andATP ase activity in order to tune muscle contractile velocities. Recent studies, however, suggested that the squidDoryteuthis pealeii might be an exception; members of this species do not express muscle‐specific myosin isoforms, but instead alter sarcomeric ultrastructure to adjust contractile velocities. We investigated whether this alternative mechanism of tuning muscle contractile velocity is found in other coleoid cephalopods. We analyzed myosin heavy chain transcript sequences and expression profiles from muscular tissues of a cuttlefish,Sepia officinalis , and an octopus,Octopus bimaculoides , to determine if these cephalopods express tissue‐specific myosin heavy chain isoforms. We identified transcripts of four and six different myosin heavy chain isoforms inS. officinalis andO. bimaculoides muscular tissues, respectively. Transcripts of all isoforms were expressed in all muscular tissues studied, and thusS. officinalis andO. bimaculoides do not appear to express tissue‐specific muscle myosin isoforms. We also examined the sarcomeric ultrastructure in the transverse muscle fibers of the arms ofO. bimaculoides and the arms and tentacles ofS. officinalis using transmission electron microscopy and found that the fast contracting fibers of the prey capture tentacles ofS. officinalis have shorter thick filaments than those found in the slower transverse muscle fibers of the arms of both species. It thus appears that coleoid cephalopods, including the cuttlefish and octopus, may use ultrastructural modifications rather than tissue‐specific myosin isoforms to adjust contractile velocities. -
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