A Beetle Flight Muscle Displays Leg Muscle Microstructure

Toshiki Shimomura, Hiroyuki Iwamoto, Tat Thang Vo Doan, Shin'ichi Ishiwata, Hirotaka Sato, Madoka Suzuki

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In contrast to major flight muscles in the Mecynorrhina torquata beetle, the third axillary (3Ax) muscle is a minor flight muscle that uniquely displays a powerful mechanical function despite its considerably small volume, ∼1/50 that of a major flight muscle. The 3Ax muscle contracts relatively slowly, and in flight strongly pulls the beating wing to attenuate the stroke amplitude. This attenuation leads to left-right turning in flight or wing folding to cease flying. What enables this small muscle to be so powerful? To explore this question, we examined the microstructure of the 3Ax muscle using synchrotron x-ray diffraction, optical microscopy, and immunoblotting analysis. We found that the 3Ax muscle has long (∼5 μm) myofilaments and that the ratio of thick (myosin) filaments to thin (actin) filaments is 1:5 or 1:6. These characteristics are not observed in the major flight muscles, which have shorter myofilaments (∼3.5 μm) with a smaller ratio (1:3), and instead are more typical of a leg muscle. Furthermore, the flight-muscle-specific troponin isoform, TnH, is not expressed in the 3Ax muscle. Since such a microstructure is suitable for generating large tension, the 3Ax muscle is appropriately designed to pull the wing strongly despite its small volume.

Original languageEnglish
Pages (from-to)1295-1303
Number of pages9
JournalBiophysical Journal
Volume111
Issue number6
DOIs
Publication statusPublished - 2016 Sep 20

Fingerprint

Beetles
Leg
Muscles
Myofibrils
Muscle Tonus
Synchrotrons
Troponin
Myosins
Actin Cytoskeleton
Immunoblotting
Microscopy
Protein Isoforms
Stroke
X-Rays

ASJC Scopus subject areas

  • Biophysics

Cite this

Shimomura, T., Iwamoto, H., Vo Doan, T. T., Ishiwata, S., Sato, H., & Suzuki, M. (2016). A Beetle Flight Muscle Displays Leg Muscle Microstructure. Biophysical Journal, 111(6), 1295-1303. https://doi.org/10.1016/j.bpj.2016.08.013

A Beetle Flight Muscle Displays Leg Muscle Microstructure. / Shimomura, Toshiki; Iwamoto, Hiroyuki; Vo Doan, Tat Thang; Ishiwata, Shin'ichi; Sato, Hirotaka; Suzuki, Madoka.

In: Biophysical Journal, Vol. 111, No. 6, 20.09.2016, p. 1295-1303.

Research output: Contribution to journalArticle

Shimomura, T, Iwamoto, H, Vo Doan, TT, Ishiwata, S, Sato, H & Suzuki, M 2016, 'A Beetle Flight Muscle Displays Leg Muscle Microstructure', Biophysical Journal, vol. 111, no. 6, pp. 1295-1303. https://doi.org/10.1016/j.bpj.2016.08.013
Shimomura T, Iwamoto H, Vo Doan TT, Ishiwata S, Sato H, Suzuki M. A Beetle Flight Muscle Displays Leg Muscle Microstructure. Biophysical Journal. 2016 Sep 20;111(6):1295-1303. https://doi.org/10.1016/j.bpj.2016.08.013
Shimomura, Toshiki ; Iwamoto, Hiroyuki ; Vo Doan, Tat Thang ; Ishiwata, Shin'ichi ; Sato, Hirotaka ; Suzuki, Madoka. / A Beetle Flight Muscle Displays Leg Muscle Microstructure. In: Biophysical Journal. 2016 ; Vol. 111, No. 6. pp. 1295-1303.
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