Ammoniacal Silver Staining of Nucleolar Organizer Regions in Four Species of Bufo

Copeia ◽  
1979 ◽  
Vol 1979 (2) ◽  
pp. 341 ◽  
Author(s):  
Melvin L. Beck ◽  
James T. Mahan
Keyword(s):  
Silver Staining ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Ammoniacal Silver

Sequential silver staining and in situ hybridization reveal a direct association between rDNA levels and the expression of homologous nucleolar organizing regions: a hypothesis for NOR structure and function

1998 ◽  
Vol 111 (10) ◽  
pp. 1433-1439
Author(s):  
F. Zurita ◽  
R. Jimenez ◽  
M. Burgos ◽  
R.D. de la Guardia
Keyword(s):  
Transcription Factors ◽  
In Situ Hybridization ◽  
Silver Staining ◽  
Organizer Region ◽  
Nucleolar Organizer ◽  
Interindividual Variation ◽  
Nucleolar Organizer Regions ◽  
Single Pair ◽  
Ribosomal Cistrons

We have developed a procedure for sequential silver staining and in situ hybridization to analyze the relationship between the amount of rDNA present in nucleolar organizer regions, as estimated by in situ hybridization, and their level of expression, as estimated by the silver signal. For simplicity we used cells from the insectivorous mole Talpa occidentalis, which have a single pair of nucleolar organizer regions in chromosome pair 3. The relative content of ribosomal cistrons was also related to the hierarchy of activation of the nucleolar organizer regions present in this chromosomal pair. Statistical analyses demonstrated that both the relative level of expression and the activation hierarchy depended mainly on the number of ribosomal cistrons in nucleolar organizer regions. We propose a functional two-step hypothesis, which is consistent with most known data concerning interchromosomal, intercellular and interindividual variation in a number of plant and animal species, including Talpa occidentalis. In step one, the first available transcription factors bind randomly to the ribosomal promoters, such that larger nucleolar organizer regions are more likely to recruit them. In the second step the remaining transcription factors are recruited in a cooperative way, thus completing activation of one nucleolar organizer region, before the next one becomes active.

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.

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.

Nucleolar organizer activity at meiosis in wheat–rye hybrid plants

1986 ◽  
Vol 28 (2) ◽  
pp. 227-234 ◽  
Author(s):  
N. Cuñado ◽  
M. C. Cermeño ◽  
J. Orellana
Keyword(s):  
Silver Staining ◽  
Staining Method ◽  
Nucleolar Organizer ◽  
The Other ◽  
Nucleolar Organizer Regions ◽  
Binucleate Cells ◽  
Hybrid Plants ◽  
Nucleolar Organizer Activity ◽  
Silver Staining Method ◽  
Organizer Activity

Nucleoli and nucleolar organizer regions (NORs) have been studied by a silver staining method in all meiotic stages of wheat–rye hybrid plants. The maximum number of nucleoli per cell scored at meiotic prophase and tapetum binucleate cells indicates that only the NORs of 1B, 6B, and 5D wheat chromosomes are active, whereas that of chromosome IR (SAT) of rye is inactive. However, at diakinesis, metaphase and anaphase meiotic stages only chromosomes 1B and 6B show Ag-NOR as was reported previously in somatic metaphase. The absence of Ag-NOR on chromosome 5D has been imputed to its low nucleolar organizer activity, not detectable by silver staining, because of the small number of rDNA clusters it carries. On the other hand, the meiotic behaviour of chromosomes 1B and 6B has been studied at metaphase I and anaphase I, using the Ag-NORs as cytological markers.Key words: nucleolar organizer, Ag-NOR, meiosis, wheat–rye hybrids.

scholarly journals Silver staining of the nucleolar organizer regions (NORs) on Lowicryl and cryo-ultrathin sections.

1985 ◽  
Vol 33 (5) ◽  
pp. 389-399 ◽  
Author(s):  
F J Moreno ◽  
D Hernandez-Verdun ◽  
C Masson ◽  
M Bouteille
Keyword(s):  
Silver Staining ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Enzymatic Digestion ◽  
Rnase A ◽  
Micrococcal Nuclease ◽  
Nucleolar Organizer Regions ◽  
Step Procedure ◽  
Ultrathin Sections

Nucleolar organizer region (NOR) silver staining was applied to sections of fixed material. A positive reaction on cryo-ultrathin sections was found as well as on semithin and ultrathin Lowicryl sections. Repeatable staining that was easy to control was obtained by a one-step procedure after aldehyde-Carnoy fixation. Fixation of the material by formaldehyde and glutaraldehyde alone in cacodylate buffer also maintained reaction selectivity when ammonium chloride was used after fixation. Enzymatic digestion by pronase, RNase A, DNase I, or micrococcal nuclease was applied to ultrathin Lowicryl sections. Pronase digestion removed the silver-stained proteins, whereas digestion by the nucleases did not. A routine procedure is proposed for easy NOR silver staining of sections that preserves a good tissue ultrastructure and is also compatible with cytochemical and immunological investigations.

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