A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of basidiomycete fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types. It is used to maintain genetic variation within the hypha much like the mechanisms found in croziers (hooks) during the sexual reproduction of ascomycetes.[1]
Clamp connections in MitosisClamp connection formation between two nuclei (one shown in green, the other orange)
Clamp connections are formed by the terminal hypha during elongation. Before the clamp connection is formed this terminal segment contains two nuclei. Once the terminal segment is long enough it begins to form the clamp connection. At the same time, each nucleus undergoes mitotic division to produce two daughter nuclei. As the clamp continues to develop it uptakes one of the daughter (green circle) nuclei and separates it from its sister nucleus. While this is occurring the remaining nuclei (orange circles) begin to migrate from one another to opposite ends of the cell. Once all these steps have occurred a septum forms, separating each set of nuclei.[2]
Use in classificationedit
Clamp connections are structures unique to the phylum Basidiomycota. Many fungi from this phylum produce spores in basidiocarps (fruiting bodies, or mushrooms), above ground. Though clamp connections are exclusive to this phylum, not all species of Basidiomycota possess these structures. As such, the presence or absences of clamp connections has been a tool in categorizing genera and species.[3][4]
Fossil recordedit
A fungal mycelium containing abundant clamp connections was found that dated to the Pennsylvanian era (298.9–323.2 Mya). This fossil, classified in the form genusPalaeancistrus, has hyphae that compare with extant saprophytic basidiomycetes.[5] The oldest known clamp connections exist in hyphae present in the fossil fern Botryopteris antiqua, which predate Palaeancistrus by about 25 Ma.[6]
Referencesedit
^C.J. Alexopolous, Charles W. Mims, M. Blackwell et al., Introductory Mycology, 4th ed. (John Wiley and Sons, Hoboken NJ, 1996) ISBN0-471-52229-5
^Kuo M. "Using a Microscope: Clamp Connections". MushroomExpert.Com. Retrieved 2010-12-15.
^Furtado, João S. (1966). "Significance of the clamp-connection in the basidiomycetes". Persoonia. 4 (1): 125–144.
^Dennis, Robert L. (1970). "A middle Pennsylvanian basidiomycete mycelium with clamp connections". Mycologia. 62 (3): 578–584. doi:10.2307/3757529. JSTOR 3757529.
clamp, connection, clamp, connection, hook, like, structure, formed, growing, hyphal, cells, certain, fungi, characteristic, feature, basidiomycete, fungi, created, ensure, that, each, cell, segment, hypha, separated, septa, cross, walls, receives, differing, . A clamp connection is a hook like structure formed by growing hyphal cells of certain fungi It is a characteristic feature of basidiomycete fungi It is created to ensure that each cell or segment of hypha separated by septa cross walls receives a set of differing nuclei which are obtained through mating of hyphae of differing sexual types It is used to maintain genetic variation within the hypha much like the mechanisms found in croziers hooks during the sexual reproduction of ascomycetes 1 A Gymnopilus clamp connection Contents 1 Formation 2 Use in classification 3 Fossil record 4 ReferencesFormation edit nbsp Clamp connections in Mitosis nbsp Clamp connection formation between two nuclei one shown in green the other orange Clamp connections are formed by the terminal hypha during elongation Before the clamp connection is formed this terminal segment contains two nuclei Once the terminal segment is long enough it begins to form the clamp connection At the same time each nucleus undergoes mitotic division to produce two daughter nuclei As the clamp continues to develop it uptakes one of the daughter green circle nuclei and separates it from its sister nucleus While this is occurring the remaining nuclei orange circles begin to migrate from one another to opposite ends of the cell Once all these steps have occurred a septum forms separating each set of nuclei 2 Use in classification editClamp connections are structures unique to the phylum Basidiomycota Many fungi from this phylum produce spores in basidiocarps fruiting bodies or mushrooms above ground Though clamp connections are exclusive to this phylum not all species of Basidiomycota possess these structures As such the presence or absences of clamp connections has been a tool in categorizing genera and species 3 4 Fossil record editA fungal mycelium containing abundant clamp connections was found that dated to the Pennsylvanian era 298 9 323 2 Mya This fossil classified in the form genus Palaeancistrus has hyphae that compare with extant saprophytic basidiomycetes 5 The oldest known clamp connections exist in hyphae present in the fossil fern Botryopteris antiqua which predate Palaeancistrus by about 25 Ma 6 References edit C J Alexopolous Charles W Mims M Blackwell et al Introductory Mycology 4th ed John Wiley and Sons Hoboken NJ 1996 ISBN 0 471 52229 5 Clamp Connection Formation hawaii edu Kuo M Using a Microscope Clamp Connections MushroomExpert Com Retrieved 2010 12 15 Furtado Joao S 1966 Significance of the clamp connection in the basidiomycetes Persoonia 4 1 125 144 Dennis Robert L 1970 A middle Pennsylvanian basidiomycete mycelium with clamp connections Mycologia 62 3 578 584 doi 10 2307 3757529 JSTOR 3757529 Krings Michael Dotzler Nora Galtier Jean Taylor Thomas N 2011 Oldest fossil basidiomycete clamp connections Mycoscience 52 1 18 23 doi 10 1007 s10267 010 0065 4 hdl 1808 13681 S2CID 86132001 Retrieved from https en wikipedia org w index php title Clamp connection amp oldid 1204535694, wikipedia, wiki, book, books, library,
