Table 3.

Summary of observations on dogfish muscle and comparison with other species

		Dogfish S. canicula	Frog R. esculenta (thermody)	Frog R. esculenta (mechs)	Frog R. temporaria (mech/X-rays)	Rabbit skinned fibres no Dextran		Rabbit skinned fibres + 4% Dextran
A. Measurements normalised by CSA and quantities calculated from them
Isometric force	kPa	177 ± 13	1721	15523	2404	1905		2645
Filament compliance	nm/MPa	17.1 ± 1.0		12.5 ± 0.323	13.3 ± 0.44	21.0 ± 3.35		15.4 ± 1.25
Sarcomere compliance	nm/MPa	32.4 ± 1.6	23.31	25.123	20.44	43.05		26.45
Sarcomere compliance in rigor	nm/MPa	20.9 ± 0.6		15.42	15.44	28.25		18.65
Myosin head Strain	nm	2.27 ± 0.13	1.74 ± 0.251	1.76 ± 0.052	1.71 ± 0.144	4.03 ± 0.385		3.17 ± 0.285
z	nm	3.78 ± 0.22	2.90 ± 0.42			5.04
Compliance of attached Myosin heads in rigor	nm/MPa	3.8		2.9	2.1	7.2		3.2
B. Myosin head sites per CSA and measurements normalised by myosin head site
Myosin to myosin spacing	nm	43.3		41.0		48.86
Myofibrillar volume density	%	77.87		83		83*
Myosin head sites per CSA	μm−2	140,871		152,5128		119,800§		166,522§
Isometric force per Myosin head site	pN	1.26 ± 0.09	1.13	1.02	1.57	1.59		1.59
C. Proportion of myosin heads attached (nATT) and quantities dependent on proportion attached
Proportion attached from rigor observations		0.25 ± 0.08		0.23	0.30	0.335		0.295
Proportion attached from thermodynamic method		0.29 ± 0.04	0.221			0.315
Weighted mean of both methods		0.28 ± 0.04			0.30		0.32
Force per attached XB	pN	4.5 ± 0.66	5.14	4.43	5.29			5.48
Myosin head stiffness	pN nm−1	1.98 ± 0.31	2.95 ± 0.46	2.52 ± 0.45	3.09 ± 0.76			1.72 ± 0.26

Bold numbers are quantities calculated from the other entries in the Table. Dogfish and frog: 5oC. Rabbit: 12oC. Abbreviations: S, Scyliorhinus; R, Rana; thermody, thermodynamic; mech, mechanics.

¹(Decostre et al., 2005)

²(Fusi et al., 2010)

³(Brunello et al., 2009)

⁴(Piazzesi et al., 2007)

⁵(Linari et al., 2007)

⁶(Kawai et al., 1993)

⁷(Bone et al., 1986)

⁸(Barclay et al., 2010) (Appendix 1 and references therein)

^*as assumed for rabbit psoas muscle in (Linari et al., 2007)

^§Myosin head sites per CSA is given here in the absence of Dextran. Note that rabbit data from measurements made in Dextran is related to CSA measured without Dextran.