Ultrastructure of the collagen fibril. II. Evidence of the spiral organization of the fibril.
Unfixed tissue from the human ovary, the tail tendon and skin from the tail of rats are incubated in 5% solutions of uranyl acetate. The collagen fibrils of all tissues are decomposed and display an obvious tridimensional spiral structure on all levels. The fibril is a complex biopolymer constructed out of filaments, surrounded by and associated with an amorphous cementing matrix. The filaments consist of 3 to 5 subfilaments with a thickness of 30--45 A spirally wound around one another. The filaments are twisted along the length of the axis of the fibril under a definite angle of inclination and a pitch of the spiral equal to 1.04--1.12 micrometer for the ovary and from 2.6 to over 5.6 micrometer for the tail tendon. The cross striations seem to spring out of the nodular thickenings along the filaments. Bridge-like connections corresponding to the separate striations are established between adjacent fibrils. A new tridimensional structure model of the collagen fibrils is proposed.
D000818:Animals; D003094:Collagen; D003238:Connective Tissue / Q000378:metabolism / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D010053:Ovary / Q000648:ultrastructure; D051381:Rats; D012867:Skin / Q000648:ultrastructure; D013623:Tail / Q000648:ultrastructure; D013710:Tendons / Q000648:ultrastructure
D003094:Collagen