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Tritium and Autoradiography in Cell Biology; Tritium et Autoradiographie en Biologie Cellulaire; 0422 0440 0438 0414 ; El Tritio 0443 la Tecnica Autorradiografica en Citobiologia

Conference:

Abstract

Because tritium emits low energy beta radiation, it is the most useful isotope for high resolution autoradiography. The relative abundance of hydrogen in most biologically important substances combined with a relatively short half-life allows the labelling of cellular components at specific activities that can often be detected at intracellular dimensions by the use of nuclear emulsions. The cells are attached to glass by various cytological procedures and after fixation a -wet or fluid photographic emulsion is applied directly to the cell surface and allowed to dry. After exposure the emulsion is developed while still in contact with the biological specimen. The preparation, an autoradiogram, when viewed under the light microscope shows the cellular structures and the location of the isotope with a resolution of less than 1 pm. In this way the distribution of tritium-labelled deoxyribonucleic acid (DNA) of individual chromosomes has been traced through two to three cell divisions. These studies were made possible by the preparation of tritiated thymidine which is a highly selective label for DNA and is quickly depleted when the cell is removed from the environment containing the labelled thymidine. The technique has yielded information on the mechanism of DNA replication, structure and reproduction of  More>>
Authors:
Taylor, J. H. [1] 
  1. Departments of Botany and Zoology, Columbia University, New York, NY (United States)
Publication Date:
Feb 15, 1962
Product Type:
Conference
Resource Relation:
Conference: Symposium on the Detection and Use of Tritium in the Physical and Biological Sciences, Vienna (Austria), 3-10 May 1961; Other Information: 19 refs., 1 fig.; Related Information: In: Tritium in the Physical and Biological Sciences. Vol. II. Proceedings of the Symposium on the Detection and Use of Tritium in the Physical and Biological Sciences| 456 p.
Subject:
60 APPLIED LIFE SCIENCES; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY AND NUCLEAR CHEMISTRY; AUTORADIOGRAPHY; BIOLOGY; CELL DIVISION; CHROMOSOMES; DNA; DNA REPLICATION; LABELLING; NUCLEAR EMULSIONS; PHOTOGRAPHIC EMULSIONS; PROTEINS; REPRODUCTION; RNA; THYMIDINE; TRITIUM
OSTI ID:
22190100
Research Organizations:
International Atomic Energy Agency, Vienna (Austria); Joint Commission on Applied Radioactivity of the International Council of Scientific Unions, Paris (France)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3703014585
Submitting Site:
INIS
Size:
page(s) 221-227
Announcement Date:
Feb 13, 2014

Conference:

Citation Formats

Taylor, J. H. Tritium and Autoradiography in Cell Biology; Tritium et Autoradiographie en Biologie Cellulaire; 0422 0440 0438 0414 ; El Tritio 0443 la Tecnica Autorradiografica en Citobiologia. IAEA: N. p., 1962. Web.
Taylor, J. H. Tritium and Autoradiography in Cell Biology; Tritium et Autoradiographie en Biologie Cellulaire; 0422 0440 0438 0414 ; El Tritio 0443 la Tecnica Autorradiografica en Citobiologia. IAEA.
Taylor, J. H. 1962. "Tritium and Autoradiography in Cell Biology; Tritium et Autoradiographie en Biologie Cellulaire; 0422 0440 0438 0414 ; El Tritio 0443 la Tecnica Autorradiografica en Citobiologia." IAEA.
@misc{etde_22190100,
title = {Tritium and Autoradiography in Cell Biology; Tritium et Autoradiographie en Biologie Cellulaire; 0422 0440 0438 0414 ; El Tritio 0443 la Tecnica Autorradiografica en Citobiologia}
author = {Taylor, J. H.}
abstractNote = {Because tritium emits low energy beta radiation, it is the most useful isotope for high resolution autoradiography. The relative abundance of hydrogen in most biologically important substances combined with a relatively short half-life allows the labelling of cellular components at specific activities that can often be detected at intracellular dimensions by the use of nuclear emulsions. The cells are attached to glass by various cytological procedures and after fixation a -wet or fluid photographic emulsion is applied directly to the cell surface and allowed to dry. After exposure the emulsion is developed while still in contact with the biological specimen. The preparation, an autoradiogram, when viewed under the light microscope shows the cellular structures and the location of the isotope with a resolution of less than 1 pm. In this way the distribution of tritium-labelled deoxyribonucleic acid (DNA) of individual chromosomes has been traced through two to three cell divisions. These studies were made possible by the preparation of tritiated thymidine which is a highly selective label for DNA and is quickly depleted when the cell is removed from the environment containing the labelled thymidine. The technique has yielded information on the mechanism of DNA replication, structure and reproduction of chromosomes, kinetics of cell division and more recently on the patterns and time sequence in the reproduction of different chromosomes in the same nucleus and the different parts of a single chromosome. All chromosomes studied so far contain two functional sub-units of DNA which are distributed in a semi-conservative fashion during reproduction. The two sub-units are unlike in some structural sense that limits the type of exchanges that may occur among the four sub-units of a reproducing chromosome. Present evidence on sequences leads to the hypothesis that chromosomes reproduce in a genetically controlled sequence. Further evidence on the patterns and mechanism of control of the sequence are being sought along with other related processes that involve the synthesis of chromosomal proteins and the other class of nucleic acids, ribonucleic acids. (author) [French] Du fait qu'il emet des rayons beta de faible energie, le tritium est l'isotope le plus utile pour l'autoradiographie a resolution elevee. Etant donne l'abondance relative de l'hydrogene dans la plupart des substances importantes du point de vue biologique et la periode radioactive assez courte du tritium, on peut marquer des constituants cellulaires a des activites specifiques qui sont souvent decelables au niveau intracellulaire a l'aide d'emulsions nucleaires. Les cellules sont fixees sur du verre par divers procedes cytologiques et, apres fixation, on applique directement a la surface de la cellule une emulsion photographique, humide ou fluide, qu'on laisse secher. Apres exposition, l'emulsion est developpee alors qu'elle se trouve encore en contact avec le specimen biologique. Lorsque la preparation, qui constitue un autoradiogramme, est examinee au microscope, on peut observer les structures cellulaires et l'emplacement de l'isotope, avec une resolution inferieure a un micron. On a pu ainsi determiner pendant deux ou trois divisions cellulaires la repartition de l'acide desoxyribonucleique (ADN) tritie de divers chromosomes. Ces etudes ont ete rendues possibles par la preparation de thymidine tritiee qui est un indicateur hautement selectif pour l'ADN et dont l'activite diminue rapidement lorsque l'on retire la cellule du milieu qui contient la thymidine marquee. On a egalement obtenu des renseignements sur le mecanisme de renouvellement de l'ADN, sur la structure et la reproduction des chromosomes, la cinetique de la division cellulaire et, plus recemment, sur les schemas et les phases de la reproduction des differents chromosomes d'un meme noyau ainsi que sur les differentes parties d'un meme chromosome. Dans tous les chromosomes etudies jusqu'a present on a constate que deux des constituants de l'ADN etaient repartis d'une maniere semi-reguliere pendant la reproduction. Ces deux constituants presentent certaines differences de structure qui limitent le type des echanges qui peuvent se produire entre les quatre constituants d'un chromosome en voie de reproduction. Les donnees dont on dispose actuellement permettent de supposer que les phases de la reproduction des chromosomes sont regies par des facteurs genetiques. On cherche a obtenir d'autres donnees sur les schemas et sur le mecanisme de controle des phases ainsi que sur d'autres processus connexes qui impliquent la synthese des proteines chromosomiques et de l'autre categorie d'acides nucleiques, les acides ribonucleiques. (author) [Spanish] El tritio constituye el isotopo mas apropiado para alcanzar un elevado poder de resolucion en autorradiografia, por emitir radiaciones beta de baja energia. La relativa abundancia del hidrogeno en la mayoria de las sustancias de importancia biologica, unida al periodo bastante breve del tritio, permiten marcar los componentes de las celulas con actividades especificas que a menudo pueden detectarse en dimensiones de orden intracelular con ayuda de emulsiones nucleares. Las celulas se fijan sobre un vidrio por diferentes procedimientos usados en citobiologia; a continuacion se aplica directamente a su superficie una emulsion fotografica humeda o fluida, que se deja secar. La emulsion se revela despues de la exposicion, cuando todavia se encuentra en contacto con la muestra. Examinando la preparacion (una autorradiografia) al microscopio optico, se pueden apreciar las estructuras celulares y la localizacion del isotopo, con un poder de resolucion inferior a una miera. De este modo, se ha seguido a traves de dos o tres generaciones celulares la distribucion del acido desoxirribonucleico (ADN) tritiado en los distintos cromosomas. Estos estudios pudieron realizarse gracias a la preparacion de timidina tritiada, un marcador muy selectivo del ADN, cuya actividad disminuye rapidamente cuando la celula se extrae del medio que contiene la timidina tritiada. Por este procedimiento se ha obtenido informacion sobre el mecanismo de duplicacion del ADN, la estructura y reproduccion de los cromosomas, la cinetica de la division celular y, mas recientemente, sobre el regimen y orden cronologico de reproduccion de diferentes cromosomas en el mismo nucleo y de las diferentes partes de un mismo cromosoma. Todos los cromosomas estudiados hasta ahora contienen dos fracciones funcionales de ADN que se distribuyen de manera aproximadamente uniforme durante la reproduccion. Las dos fracciones son desiguales en cierto sentido estructural que limita el tipo de intercambios que pueden producirse entre las cuatro fracciones del cromosoma en reproduccion. Los daios obtenidos sobre la cronologia de esos fenomenos permiten suponer que los cromosomas se reproducen en un orden controlado geneticamente. En la actualidad se procura obtener mas datos sobre el regimen y el mecanismo de control del orden en que se desarrollan los fenomenos, asi como sobre otros procesos conexos, entre ellos la sintesis de proteinas cromosomicas y de otra clase de acidos nucleicos, a saber, los acidos ribonucleicos. (author) [Russian] Poskol'ku tritij izluchaet beta-radiaciju nizkoj jenergii, on predstavljaet soboj naibolee poleznyj izotop, obespechivajushhij vysokuju razreshajushhuju sposobnost' pri radioavtografii. Otnositel'naja rasprostranennost' vodoroda v bol'shinstve biologicheski vazh- nyh veshhestv v sochetanii so sravnitel'no korotkim periodom poluraspada poz- voljaet metit' kletochnye komponenty pri udel'nyh aktivnostjah, kotorye za- chastuju mogut byt' obnaruzheny pri mezhkletochyh razmerah s pomoshh'ju jadernyh jemul'sij. Kletki prikrepljajutsja k steklu razlichnymi citologicheskimi meto- dami, i posle fiksacii mokraja ili zhidkaja fotojemul'sija prikrepljaetsja nepo- sredstvenno k poverhnosti kletki, posle chego ej dajut vozmozhnost' vysohnut'. Posle obluchenija jemul'sija projavljaetsja eshhe v kontakte s biologicheskim obrazcom. Preparat - radioavtogramma - pri rassmotrenii cherez svetovoj mikroskop pokazyvaet kletochnye struktury i raspredelenie izotopov s razreshajushhej sposobnost'ju menee odnogo mikrona. Takim obrazom udalos' prosledit' cherez dva-tri delenija kletki raspredelenie mechennoj tritiem dezoksiribonuklei- novoj kisloty (DNK) otdel'nyh hromosom. Jeti issledovanija okazalis' vozmozh- nymi v rezul'tate podgotovki tritirovannogo timidina, kotoryj jaljaetsja ves'- ma podhodjashhim metjashhim veshhestvom dlja DNK i bystro istoshhaetsja pri udalenii kletki iz sredy, soderzhashhej mechenyj timidin. Jetot metod dal informaciju o mehanizme vosstanovlenija DNK, strukture i razmnozhenii hromosom, kinetike delenija kletki i sovsem nedavno o sheme i po- sledovatel'nosti vo vremeni razmnozhenija razlichnyh hromosom v odnom i tom zhe jadre i razlichnyh chastjah odnoj hromosomy. Vse izuchennye do sih por hromo- somy imejut dva funkcional'nyh podkomponenta DNK, kotorye rasprostranja- jutsja polukonservativnym obrazom vo vremja razmnozhenija. Jeti dva podkompo- nenta razlichny v opredelennom strukturnom smysle, chto ogranichivaet takoj tip obmena, kotoryj mozhet proishodit' mezhdu chetyr'mja podkomponentami razmno zhajushhejsja hromosomy. Sovremennye dannye o posledovatel'nosti vedut k gipoteze o tom, chto hromosomy razmnozhajutsja v gineticheski kontroliruemoj posledo- vatel'nosti. Vedutsja poiski novyh dannyh po shemam i mehanizmu kontrolja posledovatel'nosti vmeste s prochimi svjazannymi s jetim processami, kotorye zatragivajut sintez hromosomnyh proteinov i drugoj klass nukleinovyh kislot - ribonukleinovye kisloty. (author)}
place = {IAEA}
year = {1962}
month = {Feb}
}