Microfibril

Microfibril

The microfibril is a very fine fibril, or fiber-like strand, consisting of glycoproteins and cellulose. It is usually, but not always, used as a general term in describing the structure of protein fiber, examples are hair and sperm tail. Its most frequently observed structural pattern is 9+2 pattern in which two central protofibrils are surrounded by nine other pairs. Cellulose inside plants is one of the examples of non-protein compounds that are using this term with the same purpose. Cellulose microfibrils are laid down in the inner surface of the primary cell wall. As the cell absorbs water, its volume increases and the existing microfibrils separate and new ones are formed to help increase cell strength.

Synthesis and Function

The cellulose is synthesized by cellulose synthase or Rosette terminal complexes which reside on a cells membrane. As cellulose fibrils are synthesized and grow extracellularly they push up against neighboring cells. Since the neighboring cell can not move easily the rosette complex is instead pushed around the cell through the fluid phospholipid membrane. Eventually this results in the cell becoming wrapped in a microfibril layer. This layer becomes the cell wall. The organization of microfibrils forming the primary cell wall are rather disorganized. However, another mechanism is used in secondary cell walls leading to its organization. Essentially, lanes on the secondary cell wall are built with microtubules. These lanes force microfibrils to remain in a certain area while they wrap. During this process microtubules can spontaneously depolymerize and repolymerize in a different orientation. This leads to a different direction in which the cell continues getting wrapped.

Marfan Syndrome

In Marfan syndrome, there is a defect in fibrillin, the glycoprotein component of microfibrils.[1]

References

  1. ^ Ursus-Nikolaus Riede, Martin Werner, Color atlas of pathology: pathologic principles, associated diseases, sequela





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  • microfibril — Basic structural unit of the plant cell wall, made of cellulose in higher plants and most algae, chitin in some fungi, and mannan or xylanin a few algae. Higher plant microfibrils are about 10nm in diameter, and extremely long in relation to… …   Dictionary of molecular biology

  • microfibril — noun Date: 1938 a fine fibril; especially one of the submicroscopic elongated bundles of cellulose of a plant cell wall • microfibrillar adjective …   New Collegiate Dictionary

  • microfibril — n. [Gr. mikros, small; L. dim. fibra, fiber] Microscopic or submicroscopic fiber …   Dictionary of invertebrate zoology

  • microfibril — /muy kroh fuy breuhl, fib reuhl/, n. Cell Biol. a microtubule, microfilament, or other fine threadlike structure of a cell. [1935 40; MICRO + FIBRIL] * * * …   Universalium

  • microfibril — noun A bundle of cellulose polymer chains held together by weak bonds …   Wiktionary

  • microfibril — A very small fibril having an average diameter of 13 nm; it may be a bundle of still smaller elements, the microfilaments. * * * mi·cro·fi·bril fīb rəl, fib n an extremely fine fibril mi·cro·fi·bril·lar rə lər adj * * * mi·cro·fi·bril… …   Medical dictionary

  • microfibril — mi·cro·fibril …   English syllables

  • microfibril — mi•cro•fi•bril [[t]ˌmaɪ kroʊˈfaɪ brəl[/t]] n. hic (lab cbl) a microtubule, microfilament, or other fine threadlike cell structure • Etymology: 1935–40 …   From formal English to slang

  • microfibril — Microscopic fibres visible only at the high magnification of the electron microscope …   Glossary of Biotechnology

  • microfibril — …   Useful english dictionary

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