A lamella (plural: "lamellae") in biology refers to a thin layer, membrane or plate of tissue.[1] This is a very broad definition, and can refer to many different structures. Any thin layer of organic tissue can be called a lamella and there is a wide array of functions an individual layer can serve. For example, an intercellular lipid lamella is formed when lamellar disks fuse together to form a lamellar sheet. It is believed that these disks are formed from vesicles, giving the lamellar sheet a lipid bilayer that plays a role in water diffusion.[2]
Another instance of cellular lamellae can be seen in chloroplasts. Thylakoid membranes are actually a system of lamellar membranes working together, and are differentiated into different lamellar domains. This lamellar system allows plants to convert light energy into chemical energy.[3] Chloroplasts are characterized by a system of membranes embedded in a hydrophobic proteinaceous matrix, or stroma. The basic unit of the membrane system is a flattened single vesicle called the thylakoid; thylakoids stack into grana. All the thylakoids of a granum are connected with each other, and the grana are connected by intergranal lamellae.[4]
It is placed between the two primary cell walls of two plant cells and made up of intracellular matrix. The lamella comprises a mixture of polygalacturons (D-galacturonic acid) and neutral carbohydrates. It is soluble in the pectinase enzyme.
Lamella, in cell biology, is also used to describe the leading edge of a motile cell, of which the lamellipodia is the most forward portion.[5]
The lipid bilayer core of biological membranes is also called lamellar phase.[6] Thus, each bilayer of multilamellar liposomes and wall of a unilamellar liposome is also referred to as a lamella.
See also
- Middle lamella
- Thylakoid
- Lipid bilayer
References
- ^ Merriam-webster.com. (2017). Definition of LAMELLA. [online] Available at: https://www.merriam-webster.com/dictionary/lamella
- ^ Swartzendruber, Donald C; Wertz, Philip W; Kitko, David J; Madison, Kathi C; Downing, Donald T (1989). "Molecular models of the Intercellular Lipid Lamellae in Mammalian Stratum Corneum". Journal of Investigative Dermatology. 92 (2): 251–7. doi:10.1111/1523-1747.ep12276794. PMID 2918233.
- ^ Shimoni, E (2005). "Three-Dimensional Organization of Higher-Plant Chloroplast Thylakoid Membranes Revealed by Electron Tomography". The Plant Cell Online. 17 (9): 2580–6. doi:10.1105/tpc.105.035030. JSTOR 4130938. PMC 1197436. PMID 16055630.
- ^ Oxford Dictionary of Biochemistry and Molecular Biology, Oxford University Press
- ^ "The Cytoskeleton and Cell Migration - Lamellipodia".
- ^ Gabriel, Jean-Christophe P.; Camerel, Franck; Lemaire, Bruno J.; Desvaux, Hervé; Davidson, Patrick; Batail, Patrick (2001). "Swollen liquid-crystalline lamellar phase based on extended solid-like sheets". Nature. 413 (6855): 504–508. doi:10.1038/35097046. PMID 11586355.
Further reading
- Yashroy, R. C (1990). "Lamellar dispersion and phase separation of chloroplast membrane lipids by negative staining electron microscopy". Journal of Biosciences. 15 (2): 93–8. doi:10.1007/BF02703373.