Muscle birefringence

Godfraind-De Becker A, Gillis JM (1988) Analysis of the birefringence of the smooth muscle anococcygeus of the rat, at rest and in contraction. I. J Muscle Res Cell Motil 1988 9 9-17... 

The birefringence of muscle decreases only very slightly in isometric contraction (von Muralt, 1932), but very considerably when shortening takes place (von Ebner, 1916), and its value is determined overwhelm-... 

These two possibilities lead to different consequences in explaining the double refraction of muscle. The A bands are ten times more birefringent than the I bands (Schmidt, 1934) and the first alternative would make possible the assumption that the L-myosin between the... 

It may be remarked that the second of the assumptions about the structure of the fibrils by no means makes it necessary to invoke a theory involving compensation. It is certain that the formed elements of the muscle and the models can be functionally changed both in their intrinsic and form birefringence (cf. Sections III, 3e and IV, 26), involving evidently a change in the internal structure of the actomyosin complex. It is thus quite possible that the same actomyosin filament could exist in a positively birefringent state in the A bands and in an isotropic state in the I bands. 

Cassim, J. Y., P. S. Tobias, and E. W. Taylor. 1968. Birefringence of muscle proteins and the problems of structural birefringence. Biochim. Biophys. Acta, 168 463-471. 

Polarizing microscopy is used to examine food components that exhibit birefringence (an ordered crystalline structure). Many food components are birefringent, e.g., starch, plant cell walls, specialized stone cells in some plant tissues, muscle fibers, fats from both plant and animal sources, and different types of flavor and seasoning components. 

Compounds resembling cytochrome c of heart muscle have been isolated from many sources. The cytochrome c of skeletal muscle of the king penguin has been purified by the same methods used for ox heart cytochrome c, and has been crystallized from almost saturated ammonium sulfate. A precipitate of the oxidized cytochrome was obtained that exhibited birefringence but was not crystalline addition of reducing agent to the ammonium sulfate solution permitted crystals of reduced cytochrome c to form. Measurements of the catalytic activity and extinction coefficients gave values equivalent to those of the ox heart preparation within the limits of error. In a preliminary report, the... 

The material which is stored in the heart muscle is birefringent (Scriba 1950) and stains faintly yellowish-red with hematoxylin-scarlet red. 

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