Morphometric Analysis of the Internal Ultrastructure of Mitochondria of Muscle Tissue in Horsehair Worm Gordionus alpestris (Nematomorpha)

Abstract — Internal ultrastructure of the muscle tissue mitochondria of horsehair worm Gordionus alpestris (Nematomorpha) was studied using morphometry. Surface area of the inner mitochondrial membrane per unit of the mitochondrial volume, or surface density of the inner mitochondrial membrane, was measured as a main morphometric parameter. The surface density of the inner mitochondrial membrane of the G. alpestris muscle tissue was compared to the respective parameter of the skeletal and cardiac muscle mitochondria. The surface density of the inner mitochondrial membrane of the worm was close to the surface density values of the cardimyocytes of 3-month-old mice and Wistar rats and was slightly higher than the surface density of mitochondria from the skeletal muscle of 3-month-old mice. The functional significance of the well-developed system of mitochondrial membranes of extended mitochondria of the horsehair worm is discussed as a structure necessary to ensure effective functioning of the circomyarian conntractile apparatus in the muscle tissue of the horsehair worm.