Biomaterial Database

Paramyosin structures in the thick filaments of the anterior byssus retractor muscle of Mytilus edulis. 1980

H G Heumann

Freeze-substituted cells of the anterior byssus retractor muscle of Mytilus edulis contain paramyosin filaments which exhibit a characteristic fine structure. Longitudinally sectioned filaments show a variety of band patterns, those occurring most frequently being cross, oblique or double oblique striations. The periodic spacings within one pattern are precise as can be demonstrated by Markham analysis and optical diffractometry. The patterns arise from structures in the interior of the filament since they persist in serially sectioned filaments and a layered structure is visible in cross-sectioned filaments. The different patterns are found to be convertible by rotating the grid around the filament axis. The observations led to the conclusion that the paramyosin core has some kind of helical arrangement. A model is proposed which consists of concentric layers of parallel paramyosin molecules which are displaced along the molecular axis in such a way that the characteristic Bear-Selby net structure results.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D008961	Models, Structural	A representation, generally small in scale, to show the structure, construction, or appearance of something. (From Random House Unabridged Dictionary, 2d ed)	Model, Structural,Structural Model,Structural Models
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D005615	Freezing	Liquids transforming into solids by the removal of heat.	Melting
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014335	Tropomyosin	A protein found in the thin filaments of muscle fibers. It inhibits contraction of the muscle unless its position is modified by TROPONIN.	Paramyosin,Miniparamyosin,Paratropomyosin,Tropomyosin Mg,alpha-Tropomyosin,beta-Tropomyosin,gamma-Tropomyosin,Mg, Tropomyosin,alpha Tropomyosin,beta Tropomyosin,gamma Tropomyosin
D049872	Bivalvia	A class in the phylum MOLLUSCA comprised of mussels; clams; OYSTERS; COCKLES; and SCALLOPS. They are characterized by a bilaterally symmetrical hinged shell and a muscular foot used for burrowing and anchoring.	Mussels,Bivalves,Clams,Bivalve,Bivalvias,Clam,Mussel