scholarly journals Investigation of argyrophilic nucleolar organizing region

2016 ◽  
Vol 117 (06) ◽  
pp. 345-350 ◽  
Author(s):  
M. Nisari ◽  
R. Eroz ◽  
M. Nisari ◽  
T. Ertekin ◽  
M. Oktay ◽  
...  
Keyword(s):  
Nucleolar Organizing Region

scholarly journals May argyrophilic nucleolar organizing region-associated protein synthesis be used for selecting the most reliable dose of drugs such as rhamnetin in cancer treatments?

2017 ◽  
Vol 117 (11) ◽  
pp. 653-658
Author(s):  
T. Ertekin ◽  
O. Bozkurt ◽  
R. Eroz ◽  
M. Nisari ◽  
D. Bircan ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Cancer Treatments ◽  
Nucleolar Organizing Region

scholarly journals Characterization of eight species of Aloe (Asphodelaceae) from the nucleolar organizing region

Rodriguésia ◽  
2018 ◽  
Vol 69 (2) ◽  
pp. 363-372
Author(s):  
Ysbelia Sánchez-G ◽  
María B. Raymúndez ◽  
José Imery ◽  
M. Cristina Acosta ◽  
Eduardo Moscone
Keyword(s):  
Subtelomeric Region ◽  
Interphase Nuclei ◽  
Nucleolar Organizing Region ◽  
Subtelomeric Regions

Abstract Nucleolar organizing region of eight species of Aloe was analyzed in somatic metaphases and interphase nuclei. All species showed a uniform 2n=14, with eight large chromosomes and six small chromosomes. Satellites were observed on the long arm of one or two pairs of large chromosomes and/or on the short arm of one of the small pairs. The silver-stained nucleolus organizing regions were located on the subtelomeric region of the long arm of one or two pairs of large chromosomes, except for Aloe dichotoma and Aloe maculata, which the AgNORs were located at a short arm of one of their small chromosomes. In most studied species, the active AgNOR number was four. However, this number changing from one to eight. For all species, the interphase number of nucleoli can be one or two, while, in Aloe excelsa, this number can be changing from one to eight. Polymorphism of active AgNORs and the number of interphase nucleoli were revealed, except for Aloe petricola, which active AgNORs were located only in the subtelomeric regions at the long arm of one of the L2 chromosomes, as well as in the L4 pair, which is agrément with the maximum number (three) of interphase nucleoli.

Nucleolar Organizing Region (NOR) and Argentophilic Nuclear Proteins in Fertilization and Induced Parthenogenesis

1990 ◽  
pp. 207-210
Author(s):  
A. P. Dyban ◽  
E. L. Severova ◽  
E. M. Noniashvili ◽  
O. V. Zatsepina ◽  
Yu S. Chentsov
Keyword(s):  
Nuclear Proteins ◽  
Nucleolar Organizing Region

Hyperplastic foci in chronic liver disease: Their proliferative activity assessed by nucleolar organizing region

1998 ◽  
Vol 48 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Kenichi Wakasa ◽  
Tomoko Haba ◽  
Masaomi Sasaki ◽  
Masami Sakurai ◽  
Takashl Ikebe ◽  
...  
Keyword(s):  
Liver Disease ◽  
Chronic Liver Disease ◽  
Proliferative Activity ◽  
Chronic Liver ◽  
Nucleolar Organizing Region

Karyotype, C-banding, chromosomal location of active nucleolar organizing regions, and B-chromosomes in Lasius niger (Hymenoptera, Formicidae)

Genome ◽  
1990 ◽  
Vol 33 (2) ◽  
pp. 267-272 ◽  
Author(s):  
T. Palomeque ◽  
E. Chica ◽  
R. Díaz de la Guardia
Keyword(s):  
Germ Cells ◽  
Chromosomal Location ◽  
Ganglion Cells ◽  
Cerebral Ganglion ◽  
B Chromosomes ◽  
Lasius Niger ◽  
Nucleolar Organizing Regions ◽  
Nucleolar Organizing Region ◽  
C Banding ◽  
Numerical Variation

The karyotype of Lasius niger (n = 15) was analysed using C-banding and observation of nucleolar organizing region (NOR) sites. C-banding showed the existence of heterochromatin in the paracentromeric regions of all chromosomes. Two sites with primary NORs were found in chromosomes 6 and 8. Chromosome 13 showed a secondary NOR. In both cases, the NORs were located in the paracentromeric region. B-chromosomes were found in male and female germ cells. They exhibited intra- and inter-individual numerical variation. No B-chromosomes were observed in somatic cells (cerebral ganglion cells) of all castes. The Bs are telocentric, small, and clearly distinguishable from the regular members of the complement. They show positive heteropycnosis in meiotic prophase and they are highly C-band positive. The activity of NORs does not change when Bs are present. Several aspects of the behaviour of these Bs are examined.Key words: C-bands, nucleolar organizing region (primary), nucleolar oganizing region (secondary), B-chromosomes, Formicidae.

Cytogenetic studies in gomphocerine grasshoppers. II. Chromosomal location of active nucleolar organizing regions

1986 ◽  
Vol 28 (4) ◽  
pp. 540-544 ◽  
Author(s):  
Josefa Cabrero ◽  
Juan Pedro M. Camacho
Keyword(s):  
Chromosomal Location ◽  
Nucleolar Organizer ◽  
X Chromosomes ◽  
Nucleolar Organizing Regions ◽  
Nucleolar Organizing Region ◽  
Primary Activity ◽  
Cytogenetic Studies ◽  
Almost All ◽  
Active Nors

Nucleolar organizing region (NOR) location has been studied in 20 species of gomphocerine grasshoppers. In the 17 species with 2n (♀) = 17, the largest number carry an active NOR on the L2, L3, and X chromosomes. The M4, M5, M6, and S8 show NOR activity in some species, but the L1 and M7 do not carry a NOR in any. While almost all NORs on L2, L3, and X show primary activity, a majority of these on the M4, M5, M6, and S8 are secondary and express a nucleolus only in a minority of male meiocytes. The NORs are located preferentially at particular chromosomal sites; primary active NORs prevail in interstitial locations, while secondary active NORs predominate in paracentromeric locations. In the majority of the species analyzed in this report, primary and secondary active NORs coincide with C-bands. Euchorthippus pulvinatus is an exception; here NORs do not seem to be related to C-bands. However, the nucleolar-associated heterochromatin in this species can be demonstrated by a N-banding technique.Key words: nucleolar organizer, NOR (primary), C-bands, heterochromatin, NOR (secondary).

scholarly journals Ribosomal DNA Transcription-Dependent Processes Interfere with Chromosome Segregation

2006 ◽  
Vol 26 (16) ◽  
pp. 6239-6247 ◽  
Author(s):  
Brett N. Tomson ◽  
Damien D'Amours ◽  
Brittany S. Adamson ◽  
Luis Aragon ◽  
Angelika Amon
Keyword(s):  
Chromosome Segregation ◽  
Ribosomal Dna ◽  
Protein Phosphatase ◽  
Genomic Region ◽  
Pol Ii ◽  
Nucleolar Organizing Region ◽  
Sister Chromatids ◽  
Rrna Transcription ◽  
Pol I ◽  
Dependent Processes

ABSTRACT The ribosomal DNA (rDNA) is a specialized genomic region not only owing to its function as the nucleolar organizing region (NOR) but also because it is repetitive in nature and, at least in budding yeast, silenced for polymerase II (Pol II)-mediated transcription. Furthermore, cohesin-independent linkages hold the sister chromatids together at the rDNA loci, and their resolution requires the activity of the conserved protein phosphatase Cdc14. Here we show that rRNA transcription-dependent processes establish linkages at the rDNA, which affect segregation of this locus. Inactivation of Cfi1/Net1, a protein required for efficient rRNA transcription, or elimination of Pol I activity, which drives rRNA transcription, diminishes the need for CDC14 in rDNA segregation. Our results identify Pol I transcription-dependent processes as a novel means of establishing linkages between chromosomes.

NULLISOMIC ANALYSIS OF NUCLEOLAR FORMATION IN ZEA MAYS

1978 ◽  
Vol 20 (1) ◽  
pp. 97-100 ◽  
Author(s):  
David F. Weber
Keyword(s):  
Zea Mays ◽  
Chromosome Number ◽  
Zea Mays L ◽  
Diploid Species ◽  
5S Rrna ◽  
Chromosome 6 ◽  
Chromosome 2 ◽  
Nucleolar Organizing Region

When a monosomic plant of a diploid species undergoes meiosis, two haploid and two nullisomic cells are produced. Zea mays L. microspore quartet cells nullisomic for chromosome number 1, 2, 4, 6, 7, 8, 9, or 10 produced by monosomics were analyzed. Cells nullisomic for chromosome 6, as expected, do not contain a nucleolus because chromosome 6 bears the nucleolar organizing region. Cells nullisomic for chromosome 2 contain nucleoli; therefore, the 5S rRNA template on chromosome 2 is not necessary for nucleolar formation. Cells nullisomic for chromosomes 1, 4, 7, 8, 9, or 10 also contain nucleoli; thus, no factors located on these chromosomes are necessary for nulceolar formation at the quartet stage.

Sign in / Sign up

Export Citation Format

Share Document