類核體

类核体(英語:nucleomorph)又稱核形體,是在隐藻[1]綠蛛網藻英语Chlorarachniophytes(屬有孔蟲界[2]叶绿体内的结构,位於其內外膜結構(periplastidial compartment)之間,為次級內共生內共生體英语Endosymbiont細胞核的殘跡。這兩類生物的葉綠體皆有四層膜,是由一個真核生物吞噬原核生物形成葉綠體後,再被另一個真核生物吞噬而來[3][4]。類核體中也具有DNA(類核體基因組),但均已大幅退化縮減,例如蓝隐藻英语Guillardia theta的類核體基因組已在2001年被定序,長度僅有551kb,只保留了513個基因[5]Bigelowiella natans英语Bigelowiella natans(一種綠蛛網藻)的類核體基因組則在2006年被定序,僅長373kb,包含331個基因。序列分析顯示隱藻的類核體來自紅藻,綠蛛網藻的類核體則來自綠藻[2]

次級內共生而成、具有四層膜的葉綠體中含有类核体

相關結構编辑

某些雙鞭毛蟲Durinskia balticaKryptoperidinium foliaceum,合稱dinotoms)的葉綠體來自矽藻,為三級內共生的產物,且其中尚存細胞核與粒線體,因此其細胞中同時含有來源不同的兩種粒線體[6]

參考文獻编辑

  1. ^ Lane, C. E.; Van Den Heuvel, K.; Kozera, C.; Curtis, B. A.; Parsons, B. J.; Bowman, S.; Archibald, J. M. Nucleomorph genome of Hemiselmis andersenii reveals complete intron loss and compaction as a driver of protein structure and function. Proceedings of the National Academy of Sciences. 2007, 104 (50): 19908–19913. Bibcode:2007PNAS..10419908L. PMC 2148396 . PMID 18077423. doi:10.1073/pnas.0707419104. 
  2. ^ 2.0 2.1 Gilson, P. R.; Su, V.; Slamovits, C. H.; Reith, M. E.; Keeling, P. J.; McFadden, G. I. Complete nucleotide sequence of the chlorarachniophyte nucleomorph: Nature's smallest nucleus. Proceedings of the National Academy of Sciences. 2006, 103 (25): 9566–9571. Bibcode:2006PNAS..103.9566G. PMC 1480447 . PMID 16760254. doi:10.1073/pnas.0600707103. 
  3. ^ Archibald, J.M.; Lane, C.E. Going, Going, Not Quite Gone: Nucleomorphs as a Case Study in Nuclear Genome Reduction. Journal of Heredity. 2009, 100 (5): 582–90. PMID 19617523. doi:10.1093/jhered/esp055. 
  4. ^ Reyes-Prieto, Adrian; Weber, Andreas P.M.; Bhattacharya, Debashish. The Origin and Establishment of the Plastid in Algae and Plants. Annual Review of Genetics. 2007, 41 (1): 147–68. PMID 17600460. doi:10.1146/annurev.genet.41.110306.130134. 
  5. ^ Archibald, John M. Nucleomorph Genomes: Structure, Function, Origin and Evolution. BioEssays. 2007, 29 (4): 392–402. PMID 17373660. doi:10.1002/bies.20551. 
  6. ^ Imanian B, Pombert JF, Dorrell RG, Burki F, Keeling PJ. Tertiary endosymbiosis in two dinotoms has generated little change in the mitochondrial genomes of their dinoflagellate hosts and diatom endosymbionts.. PLoS One. 2012, 7 (8): e43763. PMC 3423374 . PMID 22916303. doi:10.1371/journal.pone.0043763.