Populational polymorphisms in silver staining of nucleolus organizer regions (NORs) in human acrocentric chromosomes

1979 ◽  
Vol 51 (3) ◽  
Author(s):  
A.-V. Mikelsaar ◽  
T. Ilus
Keyword(s):  
Silver Staining ◽  
Nucleolus Organizer ◽  
Nucleolus Organizer Regions ◽  
Acrocentric Chromosomes

Frequency of Ag-stained nucleolus organizer regions in the acrocentric chromosomes of man

1977 ◽  
Vol 37 (1) ◽  
pp. 73-77 ◽  
Author(s):  
A. V. Mikelsaar ◽  
M. Schmid ◽  
W. Krone ◽  
H. G. Schwarzacher ◽  
W. Schnedl
Keyword(s):  
Nucleolus Organizer ◽  
Nucleolus Organizer Regions ◽  
Acrocentric Chromosomes

scholarly journals Silver staining of the nucleolus organizer regions (NOR) requires clusters of sulfhydryl groups.

1982 ◽  
Vol 30 (9) ◽  
pp. 908-911 ◽  
Author(s):  
A De Capoa ◽  
M Ferraro ◽  
P Lavia ◽  
F Pelliccia ◽  
A Finazzi-Agrò
Keyword(s):  
Heavy Metals ◽  
Silver Staining ◽  
Reducing Agents ◽  
Nucleolus Organizer ◽  
The Other ◽  
Nuclear Proteins ◽  
Staining Reaction ◽  
Nucleolus Organizer Regions ◽  
High Affinity ◽  
Per Se

Silver stainability of nucleolus organizer regions (NORs) appears to be correlated with the presence of grouped sulfhydryl (SH) side chains of proteins. In fact, heavy metals with high affinity for SH groups, such as Hg and Cu, do prevent the silver staining reaction. Ferricyanide, which is known to oxidize SH to disulfides, also prevents any further reaction with silver. On the other hand, alkali and reducing agents (mercaptoethanol, cyanide) do not affect silver stainability of the NORs. These results show that the silver staining reaction is not related to disulfide or persulfide groups and that alkali-soluble, acidic nuclear proteins per se do not play a major role in this process.

Comparison of silver staining of nucleolus organizer regions in human lymphocytes and fibroblasts

1978 ◽  
Vol 42 (3) ◽  
pp. 291-299 ◽  
Author(s):  
A. -V. Mikelsaar ◽  
H. G. Schwarzacher
Keyword(s):  
Silver Staining ◽  
Human Lymphocytes ◽  
Nucleolus Organizer ◽  
Nucleolus Organizer Regions

scholarly journals Comparative cytogenetic of six species of Amazonian Peacock bass (Cichla, Cichlinae): intrachromosomal variations and genetic introgression among sympatric species

2020 ◽  
Vol 14 (3) ◽  
pp. 437-451
Author(s):  
Janice Quadros ◽  
Alex M. V. Ferreira ◽  
Patrik F. Viana ◽  
Leandro Marajó ◽  
Ezequiel Oliveira ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
5S Rdna ◽  
Heterochromatic Region ◽  
Sympatric Species ◽  
Nucleolus Organizer ◽  
Genetic Introgression ◽  
Nucleolus Organizer Regions ◽  
River Region ◽  
Cytogenetic Analyses ◽  
Acrocentric Chromosomes

Cytogenetic data for the genus Cichla Bloch et Schneider, 1801 are still very limited, with only four karyotype descriptions to date. The sum of the available cytogenetic information for Cichla species, points to a maintenance of the diploid number of 48 acrocentric chromosomes, considered a typical ancestral feature in cichlids. In the current study, we performed molecular and classical cytogenetic analyses of the karyotype organization of six species of Cichla, the earliest-diverging genus of Neotropical cichlids. We cytogenetically analysed Cichla kelberi Kullander et Ferreira, 2006, Cichla monoculus Agassiz, 1831, Cichla piquiti Kullander et Ferreira, 2006, Cichla temensis Humboldt, 1821, Cichla vazzoleri Kullander et Ferreira, 2006 and Cichla pinima Kullander et Ferreira, 2006, including three individuals that showed mixed morphological characteristics, likely from different species, suggesting they were hybrid individuals. All individuals analysed showed 2n = 48 acrocentric chromosomes, with centromeric heterochromatic blocks on all chromosomes and a terminal heterochromatic region on the q arm of the 2nd pair. Mapping 18S rDNA gave hybridization signals, correlated with the nucleolus organizer regions, on the 2nd pair for all analyzed individuals. However, we found distinct patterns for 5S rDNA: interstitially at the proximal position on 6th pair of four species (C. kelberi, C. pinima, C. piquiti and C. vazzoleri), and on the distal of the 4th pair in two (C. monoculus and C. temensis). Accordingly, we present here new data for the genus and discuss the evolutionary trends in the karyotype of this group of fish. In addition, we provide data that supports the occurrence of hybrid individuals in the Uatumã River region, mainly based on 5S rDNA mapping.

scholarly journals Chromosome Dynamics Regulating Genomic Dispersion and Alteration of Nucleolus Organizer Regions (NORs)

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 971
Author(s):  
Hirohisa Hirai
Keyword(s):  
Transcriptional Activity ◽  
Nucleolus Organizer ◽  
Nucleolus Organizer Regions ◽  
Dispersion Systems ◽  
Rdna Loci ◽  
Silver Nitrate Staining ◽  
Staining Methods ◽  
Acrocentric Chromosomes ◽  
Reciprocal Associations

The nucleolus organizer regions (NORs) demonstrate differences in genomic dispersion and transcriptional activity among all organisms. I postulate that such differences stem from distinct genomic structures and their interactions from chromosome observations using fluorescence in situ hybridization and silver nitrate staining methods. Examples in primates and Australian bulldog ants indicate that chromosomal features indeed play a significant role in determining the properties of NORs. In primates, rDNA arrays that are located on the short arm of acrocentrics frequently form reciprocal associations (“affinity”), but they lack such associations (“non-affinity”) with other repeat arrays—a binary molecular effect. These “rules” of affinity vs. non-affinity are extrapolated from the chromosomal configurations of meiotic prophase. In bulldog ants, genomic dispersions of rDNA loci expand much more widely following an increase in the number of acrocentric chromosomes formed by centric fission. Affinity appears to be a significantly greater force: associations likely form among rDNA and heterochromatin arrays of acrocentrics—thus, more acrocentrics bring about more rDNA loci. The specific interactions among NOR-related genome structures remain unclear and require further investigation. Here, I propose that there are limited and non-limited genomic dispersion systems that result from genomic affinity rules, inducing specific chromosomal configurations that are related to NORs.

Cytological and histochemical studies on the mechanism of the selective silver staining of nucleolus organizer regions (NORs)

1979 ◽  
Vol 60 (1) ◽  
pp. 91-99 ◽  
Author(s):  
J. Olert ◽  
G. Sawatzki ◽  
H. Kling ◽  
J. Gebauer
Keyword(s):  
Silver Staining ◽  
Nucleolus Organizer ◽  
Nucleolus Organizer Regions

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 Karyotype, C-band and NOR phenotype of Anatolian endemic fish Squalius anatolicus (Bogutskaya, 1997) (Teleostei, Leuciscidae)

2021 ◽  
Vol 38 (3) ◽  
pp. 311-315
Author(s):  
Sevgi Ünal Karakuş ◽  
Muhammet Gaffaroğlu
Keyword(s):  
Chromosome Pair ◽  
Constitutive Heterochromatin ◽  
Nucleolus Organizer ◽  
Submetacentric Chromosome ◽  
Nucleolus Organizer Regions ◽  
C Banding ◽  
Nor Phenotype ◽  
Acrocentric Chromosomes ◽  
Endemic Fish ◽  
Lake Beysehir

The karyotype and distribution of constitutive heterochromatin and nucleolus organizer regions (NORs) of Anatolian leuciscine endemic to Lake Beysehir, Squalius anatolicus (Bogutskaya, 1997) were analyzed respectively using conventional Giemsa-staining, C-banding and Ag-impregnation. Diploid chromosome number was 2n = 50 and karyotype consisted of 7 pairs of metacentric, 13 pairs of submetacentric, 5 pairs of subtelo- to acrocentric chromosomes, NF value equaled 90. Heteromorphic elements indicating sex chromosomes were not detected. C-banding revealed clear pericentromeric constitutive heterochromatin blocks in several chromosomes. Ag-impregnation revealed the size heteromorphism of NORs that covered almost the entire short arms of the middle-sized submetacentric chromosome pair. The karyotype pattern and simple NOR phenotype of S. anatolicus are nearly identical with that found not only in Squalius species analyzed to date but also in many other representatives of the Eurasian leuciscine cyprinids, which indicates remarkable chromosome stasis in this leuciscid lineage.

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