Image SCE Metaphase BMC Cell Biol 2 11 6.jpg thumb upright 1.8 Metaphase spread of a cell line showing a ring chromosome R and several sister chromatid exchanges SCEs , some of which are indicated by arrows. Sister chromatid exchange SCE is the exchange of genetic material between two identical sister chromatids . It was first discovered by using the Giemsa stain ing method on one chromatid belonging to the sister chromatid complex before anaphase in mitosis . The staining revealed that few segments were passed to the sister chromatid which were not dyed. The Giemsa staining was able to stain due to the presence of bromodeoxyuridine analogous base which was introduced to the desired chromatid. The reason for the SCE is not known but it is required and used as a mutagen ic testing of many products. Four to five sister chromatid exchange per chromosome pair, per mitosis is in the normal distribution, 14 100 exchanges is not normal and presents a danger to the organism. SCE is elevated in pathologies including Bloom syndrome , in which distributions reach 100 160 per chromosome pair per mitosis. Frequent Sister Chromatid Exchange may also be related to formation of tumor s. Sister chromatid exchange has also been observed more frequently in HLA B51 B51 Beh et s disease . ref name pmid16441621 cite journal author Ikbal M, Atasoy M, Pirim I, Aliagaoglu C, Karatay S, Erdem T title The alteration of sister chromatid exchange frequencies in Beh et s disease with and without HLA B51 journal J Eur Acad Dermatol Venereol volume 20 issue 2 pages 149 52 year 2006 month February pmid 16441621 doi 10.1111 j.1468 3083.2006.01386.x url ref External links MeshName Sister chromatid exchange References reflist Genetic recombination DEFAULTSORT Sister Chromatid Exchange Category Mobile genetic elements de Schwesterchromatidaustausch ru ... more details
chembox Name 5 Ethynyl 2 deoxyuridine verifiedrevid 322007341 ImageFile 5 ethynyl 2 deoxyuridine.png ImageSize 200px IUPACName 5 Ethynyl 1 2 R ,4 S ,5 R 4 hydroxy 5 hydroxymethyl oxolan 2 yl pyrimidine 2,4 dione OtherNames 2 Deoxy 5 ethynyluridine 5 Ethynyl 2 deoxyuridine Section1 Chembox Identifiers Abbreviations EdU ChemSpiderID 414657 InChIKey CDEURGJCGCHYFH DJLDLDEBBH InChI 1 C11H12N2O5 c1 2 6 4 13 11 17 12 10 6 16 9 3 7 15 8 5 14 18 9 h1,4,7 9,14 15H,3,5H2, H,12,16,17 t7 ,8 ,9 m0 s1 StdInChI 1S C11H12N2O5 c1 2 6 4 13 11 17 12 10 6 16 9 3 7 15 8 5 14 18 9 h1,4,7 9,14 15H,3,5H2, H,12,16,17 t7 ,8 ,9 m0 s1 StdInChIKey CDEURGJCGCHYFH DJLDLDEBSA N CASNo 61135 33 9 CASNo Ref ChEMBL 222932 PubChem 472172 SMILES C C C1 C N C O NC1 O C H 2C C H O C H CO O2 MeSHName 5 ethynyl 2 deoxyuridine Section2 Chembox Properties C 11 H 12 N 2 O 5 Appearance Density MeltingPt BoilingPt Solubility Section3 Chembox Hazards MainHazards FlashPt Autoignition 5 Ethynyl 2 deoxyuridine EdU is a novel thymidine analogue, that is incorporated into dividing cells. At high doses it can be cytotoxic. Detection EdU is detected with a fluorescent azide which forms a covalent bond using click chemistry . ref cite journal author Chehrehasa F, Meedeniya AC, Dwyer P, Abrahamsen G, Mackay Sim A title EdU, a new thymidine analogue for labelling proliferating cells in the nervous system journal J. Neurosci. Methods volume 177 issue 1 pages 122 30 year 2009 month February pmid 18996411 doi 10.1016 j.jneumeth.2008.10.006 url ref ref cite journal last Cavanagh first Brenton coauthors Walker, T. Norazit, A. Meedeniya, A. C. title Thymidine analogues for tracking DNA synthesis. journal Molecules date 15 year 2011 month September volume 16 issue 9 pages 7980 93 pmid 21921870 ref Unlike the commonly used bromodeoxyuridine , EdU detection requires no heat or acid treatment. References See http en.wikipedia.org wiki Wikipedia Footnotes on how to create references using ref ref tags which will then appear here auto ... more details
italic title Taxobox name Macrostomum lignano fossil range No fossils known image Macrostomum lignano.jpg image caption Macrostomum lignano regnum Animal ia Body Plan Bilateria phylum Platyhelminthes classis Turbellaria ordo Macrostomida familia Macrostomidae genus Macrostomum species M. lignano binomial Macrostomum lignano binomial authority Ladurner, Sch rer, Salvenmoser, & Rieger, 2005 ref name description cite journal doi 10.1111 j.1439 0469.2005.00299.x last1 Ladurner first1 Peter last2 Sch rer first2 Lukas last3 Salvenmoser first3 Willi last4 Rieger first4 Reinhard title A new model organism among the lower Bilateria and the use of digital microscopy in taxonomy of meiobenthic Platyhelminthes Macrostomum lignano , n. sp. Rhabditophora, Macrostomorpha journal Journal of Zoological Systematics and Evolutionary Research volume 43 issue 2 year 2005 pages 114 126 ref Macrostomum lignano ref name description is a Wiktionary free living free living , hermaphroditic flatworm . It is transparent and of small size adults reaching about 1.7 mm , and is part of the intertidal sand meiofauna of the Adriatic Sea ref name description . Originally a model organism for research on developmental biology ref cite journal last1 Ladurner first1 P last2 Rieger first2 R last3 Bagu a first3 J display authors 1 title Spatial distribution and differentiation potential of stem cells in hatchlings and adults in the marine platyhelminth Macrostomum sp. A bromodeoxyuridine analysis volume 226 year 2000 pages 231 241 ref and the evolution of the bilaterian body plan ref cite journal doi 10.1093 icb 43.1.47 last2 Ladurner first2 P last1 Rieger first1 R title The signi cance of muscle cells for the origin of mesoderm in Bilateria journal Integrative Comparative Biology volume 43 year 2003 pages 47 57 ref , it has since expanded to other important fields of research such as sexual selection and sexual conflict s ref http evolution.unibas.ch scharer research current research macrostomum ov ... more details
The immortal DNA strand hypothesis was proposed in 1975 by John Cairns biochemist John Cairns as a mechanism for adult stem cells to minimize mutations in their genomes . ref name Cairns Cairns, J. 1975. Mutation selection and the natural history of cancer. Nature London 255 197 200. ref This hypothesis proposes that instead of segregating their DNA during mitosis in a random manner, adult stem cells divide their DNA asymmetrically, and retain a distinct template set of DNA strands parental strands in each division. By retaining the same set of template DNA strands, adult stem cells would pass mutations arising from errors in DNA replication on to non stem cell daughters that soon terminally Cellular differentiation differentiate end mitotic divisions and become a functional cell . Passing on these replication errors would allow adult stem cells to reduce their rate of accumulation of mutations that could lead to serious genetic disorder s such as cancer . Although evidence for this mechanism exists, whether it is a mechanism acting in adult stem cells in vivo is still controversial. Methods Two main assay s are used to detect immortal DNA strand segregation label retention and label release pulse chase assays. In the label retention assay, the goal is to mark immortal or parental DNA strands with a DNA label such as tritiated thymidine or bromodeoxyuridine BrdU . These types of DNA labels will incorporate into the newly synthesized DNA of dividing cells during S phase . A pulse of DNA label is given to adult stem cells under conditions where they have not yet delineated an immortal DNA strand. During these conditions, the adult stem cells are either dividing symmetrically thus with each division a new immortal strand is determined and in at least one of the stem cells the immortal DNA strand will be marked with DNA label , or the adult stem cells have not yet been determined thus their precursors are dividing symmetrically, and once they differentiate into adult st ... more details
File Proliferating cells in the dentate gyrus crop .jpg thumb 240px Bromodeoxyuridine BrdU red , a marker of DNA replication, highlights neurogenesis in the subgranular zone of hippocampal dentate gyrus . Fragment of an commons File Phenotypes of proliferating cells in the Rostral Migratory Stream and Dentate Gyrus.jpg illustration from Faiz et al., 2005. ref name pmid15826306 cite journal author Faiz M, Acarin L, Castellano B, Gonzalez B title Proliferation dynamics of germinative zone cells in the intact and excitotoxically lesioned postnatal rat brain journal BMC Neurosci volume 6 issue pages 26 year 2005 pmid 15826306 pmc 1087489 doi 10.1186 1471 2202 6 26 url http www.biomedcentral.com 1471 2202 6 26 ref Neurogenesis birth of neuron s is the process by which neurons are generated from Neural stem cell neural stem and progenitor cells . Most active during pre natal development , neurogenesis is responsible for populating the growing brain with neurons. Recently neurogenesis was shown to continue in several small parts of the brain of mammals the hippocampus and the subventricular zone . Studies have indicated that hormones, such as testosterone in vertebrates and ecdysone in invertebrates, have an influence on the rate of neurogenesis. Occurrence in adults File Doublecortin expression.png thumb right Doublecortin expression in the rat dentate gyrus , 21st postnatal day. Oomen et al., 2009. ref name dcx cite journal author Oomen CA, Girardi CE, Cahyadi R, & 39 & 39 et al.& 39 & 39 editor1 last Baune editor1 first Bernhard title Opposite effects of early maternal deprivation on neurogenesis in male versus female rats journal PLoS ONE volume 4 issue 1 pages e3675 year 2009 pmid 19180242 pmc 2629844 doi 10.1371 journal.pone.0003675 bibcode 2009PLoSO...4.3675O ref New neurons are continually born throughout adulthood in predominantly two regions of the brain The subventricular zone SVZ lining the ventricular system lateral ventricles , where neural stem cell s and progenitor ... more details
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