DIMORPHIC NUCLEOLAR ORGANIZER REGIONS IN THE FROG RANA BLAIRI

1977 ◽  
Vol 19 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Oscar G. Ward
Keyword(s):  
Species Complex ◽  
Rana Pipiens ◽  
Nucleolar Organizer ◽  
Staining Procedure ◽  
Nucleolar Organizer Regions ◽  
Specific Staining ◽  
Rana Blairi ◽  
Ammoniacal Silver ◽  
Secondary Constrictions ◽  
Unequal Length

The nucleolar organizer-specific staining procedure, ammoniacal silver (Ag-AS), has been used to study the distribution and size of the nucleolar organizer regions (NORs) in chromosomes of the frog Rana blairi (Mecham, Littlejohn, Oldham, Brown and Brown). The somatic metaphase karyotype of this frog is similar to that of other frogs of the Rana pipiens species complex, numerically (2n = 26) and morphologically. Secondary constrictions are detectable in untreated Giemsa-stained metaphase preparations as achromatic gaps in the long arms of a pair of submetacentric chromosomes (no. 10). These constrictions are the only regions which are deeply stained with the Ag-AS method and are thus identified as the nucleolar organizer regions (Ag-NORs). In each of the three individuals, the Ag-NORs as visualized on the homologues are of unequal length.

A role for upstream binding factor in organizing ribosomal gene chromatin

2006 ◽  
Vol 73 ◽  
pp. 77-84 ◽  
Author(s):  
Jane E. Wright ◽  
Christine Mais ◽  
José-Luis Prieto ◽  
Brian McStay
Keyword(s):  
Nucleolar Organizer ◽  
Ribosomal Gene ◽  
Rna Polymerase I ◽  
Nucleolar Organizer Regions ◽  
Binding Factor ◽  
Upstream Binding Factor ◽  
Acrocentric Chromosomes ◽  
Polymerase I ◽  
Secondary Constrictions ◽  
Active Nors

Human ribosomal genes are located in NORs (nucleolar organizer regions) on the short arms of acrocentric chromosomes. During metaphase, previously active NORs appear as prominent chromosomal features termed secondary constrictions, which are achromatic in chromosome banding and positive in silver staining. The architectural RNA polymerase I transcription factor UBF (upstream binding factor) binds extensively across the ribosomal gene repeat throughout the cell cycle. Evidence that UBF underpins NOR structure is provided by an examination of cell lines in which large arrays of a heterologous UBF binding sequences are integrated at ectopic sites on human chromosomes. These arrays efficiently recruit UBF even to sites outside the nucleolus, and during metaphase form novel silver-stainable secondary constrictions, termed pseudo-NORs, that are morphologically similar to NORs.

Chromosome banding in salmonid fish: nucleolar organizer regions in Salmo and Salvelinus

1985 ◽  
Vol 27 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Ruth Phillips ◽  
Peter E. Ihssen
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Brook Trout ◽  
Chromosome Banding ◽  
Lake Trout ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Banding Patterns ◽  
Single Chromosome ◽  
Secondary Constrictions

Chromosome banding patterns obtained by silver staining (Ag-NORs) were analyzed in three species of Salmo (rainbow, brown trout, and Atlantic salmon) and three species of Salvelinus (brook trout, lake trout, and arctic char). In rainbow trout and Atlantic salmon the Ag-NORs were found at the secondary constrictions of a single chromosome pair, while in brown trout the Ag-NORs were found on the short arms of one or two of the two longest subtelocentric or acrocentric chromosome pairs. The location of the Ag-NORs was multichromosomal in the three Salvelinus species, occurring on one or both members of four to six different chromosome pairs in different individuals. The Ag-NOR sites were on the short arms of some acrocentric pairs and at the telomeres of other acrocentric pairs and one or two metacentric pairs. Chromomycin A3 positive bands were found at the same sites as the Ag-NORs in all species. In the species with multichromosomal location of Ag-NORs, polymorphisms in the size and location of the NORs were extremely common, so that almost every individual fish had a different pattern of Ag-NOR sites.Key words: banding, Salmo, Salvelinus, Ag-NORs, polymorphisms, nucleolar organizer.

NUCLEOLAR ORGANIZER REGIONS IN THE RABBIT (ORYCTOLAGUS CUNICULUS) AS SHOWN BY SILVER STAINING

1978 ◽  
Vol 20 (3) ◽  
pp. 377-382 ◽  
Author(s):  
Patricia A. Martin-Deleon ◽  
Dorene L. Petrosky ◽  
M. Eileen Fleming
Keyword(s):  
New Zealand ◽  
Silver Staining ◽  
Oryctolagus Cuniculus ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Telomeric Region ◽  
Metaphase Chromosomes ◽  
Domestic Rabbit ◽  
Silver Precipitation ◽  
Secondary Constrictions

Nucleolar organizer regions (NOR's) were demonstrated in metaphase chromosomes of the domestic rabbit, Oryctolagus cuniculus (L.) (New Zealand white strain) using silver staining. Sequential quinacrine banding and a modification of the Ag-AS silver precipitation technique with duplicate photography allowed identification of silver staining NOR's on the short arms of chromosomes 13, 16, and 20, as well as the telomeric region of the long arms of number 21 in some cells. Chromosomes 13, 16 and 20 all have subterminal to terminal centromeres, often showed satellites and secondary constrictions, and were sometimes involved in associations.

scholarly journals Conserved Cytogenetic Features in the Amazonian Arapaima, Arapaima gigas (Schinz 1822) from Jamari River, Rondônia–Brazil

2009 ◽  
Vol 2 (1) ◽  
pp. 91-94 ◽  
Author(s):  
Renata da Rosa ◽  
Marceléia Rubert ◽  
Mauro Caetano-Filho ◽  
Lucia Giuliano-Caetano
Keyword(s):  
Diploid Number ◽  
Nucleolar Organizer ◽  
Pericentromeric Region ◽  
Nucleolar Organizer Regions ◽  
Fluorochrome Staining ◽  
Arapaima Gigas ◽  
Chromosomal Pair ◽  
Silver Nitrate Staining ◽  
Subterminal Region ◽  
Secondary Constrictions

Specimens of Arapaima gigas from Jamari River (RO) were cytogenetically analyzed. A diploid number of 2n=56 chromosomes was found (28m-sm + 28st-a). Secondary constrictions were observed on the short arms of chromosome 3. Nucleolar Organizer Regions (NORs) were detected at the subterminal region on short arms of the third chromosomal pair by both silver nitrate staining and FISH with 45S rDNA probe, being equivalent to secondary constrictions. The ribosomal sites were also characterized by size heteromorphism and presence of CMA3+/DAPI- blocks. The constitutive heterochromatin was located at pericentromeric region of some chromosomes. After sequential Cbanding and base-specific fluorochromes staining, most of the heterochromatins proved to be neutral, i.e., with similar amounts of AT and GC bases. Nonetheless, some heterochromatic regions were marked by GC-specific fluorochromes in one chromosomal pair and by AT-specific fluorochrome staining on two pairs. The present data are in agreement with previous reports in populations from Araguaya River, indicating that conserved cytogenetic features are present in this important fish species.

A simple two-step procedure for silver staining nucleolus organizer regions in plant chromosomes

1985 ◽  
Vol 27 (2) ◽  
pp. 255-257 ◽  
Author(s):  
Romesh C. Mehra ◽  
Susan Brekrus ◽  
Merlin G. Butler
Keyword(s):  
Vicia Faba ◽  
Allium Cepa ◽  
Silver Staining ◽  
Lens Culinaris ◽  
Nucleolar Organizer ◽  
Nucleolus Organizer ◽  
Staining Procedure ◽  
Nucleolar Organizer Regions ◽  
Nucleolus Organizer Regions ◽  
Plant Chromosomes

Nucleolus organizer regions (NORs) of Allium cepa, Lens culinaris, and Vicia faba chromosomes were stained by a two-step silver staining procedure which is simple and highly reproducible. Polymorphisms are apparent with respect to the size of NORs in the taxa understudy.Key words: nucleolar organizer regions, silver staining, Allium cepa, Lens culinaris, Vicia faba.

scholarly journals Electron microscopic studies of silver-strained proteins in nucleolar organizer regions: location in nucleoli of rat sympathetic neurons during light and dark periods

1981 ◽  
Vol 51 (1) ◽  
pp. 85-94
Author(s):  
M.J. Pebusque ◽  
R. Seite
Keyword(s):  
Dark Period ◽  
Sympathetic Neurons ◽  
Nucleolar Organizer ◽  
Fold Increase ◽  
Staining Procedure ◽  
Nucleolar Organizer Regions ◽  
Electron Microscopic ◽  
Main Site ◽  
Fibrillar Component ◽  
Silver Grains

Ag-AS staining of nucleolar organizer regions was carried out on interphasic superior cervical ganglia neurons of rats sacrificed during light and dark periods. While the Ag-AS technique has mostly been used monolayer cell lines or cell suspensions, the present study showed that in electron microscopy this technique is also applicable to small pieces of tissues. The finest pictures are obtained when (I) all solutions used for the staining procedure are at pH 4.5-4.7 and (2) the second step of the reaction involving ammoniacal silver and formalin developing solutions does not exceed 3 min. The results indicate that in the 2 time periods studied, a positive reaction took place exclusively in nucleolar fibrillar centres and in the fibrillar centres and in the fibrillar ribonucleoprotein (RNP) component (dense fibrillar component). The other nucleolar components, i.e. granular and vacuolar, were devoid of silver deposits. As previously shown in sympathetic neurons, the fibrillar centres of the nucleoli show a 10-fold increase in volume during the dark period. In this period, silver grains were located on both “giant” and small-sized fibrillar centres. The fibrillar RNP component seen either at the periphery of fibrillar centres or in the form of a well-delimited network showed the strongest reaction. The same distribution of silver grains was observed in the sympathetic neurons of rats sacrificed during the light period. Here again, silver accumulation occurred exclusively in the fibrillar centres and the fibrillar RNP component. The same difference in reactivity was observed as for the dark period, the fibrillar RNP component being the main site of the reaction.

Nucleolar competition analysis in Aegilops ventricosa and its amphiploids with tetraploid wheats and diploid rye by the silver-staining procedure

1984 ◽  
Vol 26 (1) ◽  
pp. 34-39 ◽  
Author(s):  
J. Orellana ◽  
J. L. Santos ◽  
J. R. Lacadena ◽  
M. C. Cermeño
Keyword(s):  
Secale Cereale ◽  
Silver Staining ◽  
Triticum Turgidum ◽  
Tetraploid Wheat ◽  
Nucleolar Organizer ◽  
Triticum Dicoccoides ◽  
Staining Procedure ◽  
Nucleolar Organizer Regions ◽  
Aegilops Ventricosa ◽  
Tetraploid Wheats

The nucleolar organizer activity of Aegilops ventricosa and its amphiploids with tetraploid wheats (Triticum turgidum, Triticum dicoccum, and Triticum aethiopicum) and diploid rye (Secale cereale) was analyzed by the silver-staining procedure. Triticum turgidum and Triticum dicoccoides show four Ag-NORs (silver-stained nucleolar organizer regions), in agreement with previous data. Only two Ag-NORs are detected in Ae. ventricosa (genome constitution DDMM) indicating that natural amphiplasty occurs in this allotetraploid species. No amphiplasty was observed in the Ae. ventricosa – tetraploid wheat amphiploids since six Ag-NORs were visible in all of them. On the contrary, only two Ag-NORs were detected in the Ae. ventricosa – Secale cereale amphiploid, the rye NORs being suppressed by the presence of ventricosa chromosomes. The ventricosa NORs therefore are codominant with those of tetraploid wheat (chromosomes 1B and 6B) and dominant to chromosome 1R of rye. Eleven T. aestivum – Ae. ventricosa addition lines have been also analyzed. All of them showed four Ag-NORs. Clear-cut conclusions were not reached since the added ventricosa chromosomes were not identified.

scholarly journals A multilabeling technique for simultaneous demonstration and quantitation of Ki-67 and nucleolar organizer regions (AgNORs) in paraffin-embedded tissue.

1994 ◽  
Vol 42 (6) ◽  
pp. 789-793 ◽  
Author(s):  
S Munakata ◽  
J B Hendricks
Keyword(s):  
Nucleolar Organizer ◽  
Staining Procedure ◽  
Nucleolar Organizer Regions ◽  
Nuclear Area ◽  
Human Tonsil ◽  
Ki 67 ◽  
Significant Difference ◽  
Agnor Staining ◽  
Tonsil Tissue ◽  
The Individual

Although many investigators have demonstrated a relationship between argyrophilic nucleolar organizer regions (AgNORs) and Ki-67 expression in solid tumors, no previous studies have simultaneously assessed the relationship between AgNOR and Ki-67 expression in paraffin-embedded tissue. We describe a method for simultaneous demonstration and quantitation of Ki-67 and AgNORs in routinely processed tissue. The Ki-67 equivalent monoclonal antibody MIB1, which can detect proliferative activity in routinely processed tissue with microwave heating, was employed. Fresh human tonsil tissue was fixed in formalin and embedded in paraffin for Ki-67/AgNOR dual staining. Image analysis was employed for quantitation of AgNOR staining in Ki-67-positive and Ki-67-negative nuclei. The double-staining procedure had no measurable effect on the individual parameters: Ki-67 labeling index, mean AgNOR number (NN), and NOR percentage nuclear area (NPNA). However, microwave processing for Ki-67 immunostaining significantly increased nuclear area (NA) and AgNOR area (AA). A significant difference was found between Ki-67-positive and Ki-67-negative cells for NN (p < 0.001), NA (p < 0.001), AA (p < 0.001), and NPNA (p < 0.001). These results suggest a direct relationship between AgNOR and Ki-67 in paraffin-embedded tissue.

scholarly journals Localización de satélites y cromosomas NOR para la interpretación del cariotipo de Sesbania virgata (Papilionoideae, Sesbanieae) de dos poblaciones americanas

2018 ◽  
Vol 96 (4) ◽  
pp. 619 ◽  
Author(s):  
Fernando Tapia-Pastrana ◽  
Fernando Tapia-Aguirre
Keyword(s):  
Nucleolar Organizer ◽  
Point Of View ◽  
Nucleolar Organizer Regions ◽  
Nucleolar Organization ◽  
Cytogenetic Studies ◽  
Sesbania Virgata ◽  
Satellite Chromosomes ◽  
Secondary Constrictions ◽  
Study Species ◽  
Surface Spreading

<p><strong>Background</strong>: Cytogenetic studies in the genus <em>Sesbania</em> show lack of agreement among the researchers about the precise number and position of secondary constrictions and satellites as well as their relation to the organization of the nucleolus. The lack of this information makes it difficult to carry out reliable comparative cytogenetic studies and chromosome evolution in this genus.</p><p><strong>Questions</strong>: Where are the secondary constrictions and satellites located in the chromosomes of <em>Sesbania</em> <em>virgat</em>a? Do these regions actively participate in the nucleolar organization?</p><p><strong>Study species</strong>: <em>Sesbania virgate</em> (Cav.) Pers.</p><p><strong>Study site</strong>: Municipality of Tlacotalpan, Mexico and Province of Salta, Argentina.</p><p><strong>Methods</strong>: Surface spreading and air-drying technique was applied to obtain chromosomes in prometaphase and typical metaphase from radicular meristems.</p><p><strong>Results</strong>: Each population exhibited a different karyotype and only two secondary constrictions associated with microsatellites in the short arms of the smallest chromosome pair and not in long arms as was suggested by other authors. The inclusion of secondary constrictions and satellites in the nucleolus of cells in prometaphase allowed to corroborate their active participation in the formation of this one. This information was used to reevaluate the position of the nucleolar organizer regions "NOR´s".</p><strong>Conclusions</strong>: Our results agree with the predominant point of view on the location of the "NOR´s" in the short arms of plant species, particularly in legumes. In addition, given that the populations under study are geographically isolated, we suggest that an active process of speciation manifested in the two found cytotypes whose differences are attributed to changes in the proportion of arms of the satellite chromosomes is favored.

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