scholarly journals Cytogenetic analyses of two Curimatidae species (Pisces; Characiformes) from the Paranapanema and Tietê Rivers

2007 ◽  
Vol 67 (2) ◽  
pp. 333-338 ◽  
Author(s):  
LVS De Rosa ◽  
F. Foresti ◽  
C. Martins ◽  
C. Oliveira ◽  
PE. Sobrinho ◽  
...  
Keyword(s):  
Fluorescent In Situ Hybridization ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Terminal Region ◽  
Nucleolar Organizer Regions ◽  
Micro Structure ◽  
Isolated Populations ◽  
Cytogenetic Characterization ◽  
Cytogenetic Analyses

Cytogenetic analyses were performed in two Curimatidae species (Steindachnerina insculpta and Cyphocharax modesta) from the Paranapanema and Tietê Rivers (São Paulo State, Brazil), showing a karyotype composed of 54 meta-submetacentric chromosomes in both species. Silver- and chromomycyn-staining and fluorescent in situ hybridization (FISH) using a 18S rDNA probe indicated that the nucleolar organizer regions (NORs) of both species are localized in the terminal region of the long arm of two metacentric chromosomes. Although a single NOR system was evidenced in both analyzed species, S. insculpta and C. modesta presented the nucleolar organizer regions in distinct chromosome pairs, indicating that these cistrons can be considered cytogenetic markers. Variation on the amount and distribution of the constitutive heterochromatin (C-bands) could also be detected between the two species - while S. insculpta presented few heterochromatic blocks, intensely stained C-bands were evidenced in C. modesta specially in the terminal region of the long arm of the NOR-bearing chromosomes. Although most Curimatidae species have been characterized by homogeneous karyotypes, isolated populations could be established under different environmental conditions leading to karyotype micro-structure variations specially related to the NORs localization and C-banding distribution. The obtained data were useful for the cytogenetic characterization and differentiation of S. insculpta and C. modesta and could be used in evolutionary inferences in the Curimatidae group.

scholarly journals Cytogenetic analyses in Trinomys (Echimyidae, Rodentia), with description of new karyotypes

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5316 ◽  
Author(s):  
Naiara Pereira Araújo ◽  
Cayo Augusto Rocha Dias ◽  
Rodolfo Stumpp ◽  
Marta Svartman
Keyword(s):  
Chromosome Mapping ◽  
Nucleolar Organizer ◽  
Interspecific Variation ◽  
Nucleolar Organizer Regions ◽  
45S Rdna ◽  
Banding Patterns ◽  
Pericentric Inversions ◽  
Cytogenetic Analyses ◽  
First Time

Trinomys Thomas (1921) is a terrestrial genus of spiny rats endemic to the Brazilian areas of Atlantic Forest and the transitional areas of Cerrado and Caatinga. Although most species have been already karyotyped, the available cytogenetic information is mostly restricted to diploid and fundamental numbers. We analyzed the chromosomes of two Trinomys species: Trinomys moojeni (2n = 56, FN = 106) and Trinomys setosus setosus (2n = 56, FN = 106 and 2n = 56, FN = 108). Our analyses included GTG- and CBG-banding, silver-staining of the nucleolar organizer regions, and chromosome mapping of telomeres and 45S rDNA by fluorescent in situ hybridization (FISH). Comparative GTG- and CBG-banding suggested that the interspecific variation may be due to rearrangements such as pericentric inversions, centromere repositioning, and heterochromatin variation. We report two new karyotypes for T. s. setosus and describe for the first time the banding patterns of the two Trinomys species.

scholarly journals Cytogenetics of two sympatric Corydoras species (pisces, siluriformes, challichtyidae) of Southern Brazil

2006 ◽  
Vol 66 (1b) ◽  
pp. 191-198 ◽  
Author(s):  
R. F. Artoni ◽  
M. L. Terêncio ◽  
M. R. Vicari ◽  
M. C. A. Matiello ◽  
M. M. Cestari ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Great Similarity ◽  
Southern Brazil ◽  
Rdna Probe ◽  
Karyotypic Formula

Karyotypic data are presented for two sympatric Corydoras species of the Lagoa Dourada, namely, C. ehrhadti and C. paleatus, which are found in the upper Tibagi river basin (Ponta Grossa, State of Paraná, Brazil). The same diploid number and karyotypic formula were observed in both species/populations. A great similarity in the constitutive heterochromatin distribution and in the activity of nucleolar organizer regions was also found. The use of in situ hybridization with a fluorescent 18S rDNA probe allowed for the identification of the species/populations through the location of ribosomal sites.

scholarly journals Cytogenetic characterization of Aloysia virgata Ruiz and Pavan (Verbenaceae)

2009 ◽  
Vol 52 (4) ◽  
pp. 893-899
Author(s):  
Aline Dias Brandão ◽  
Lyderson Facio Viccini ◽  
Shirlei Maria Recco-Pimentel
Keyword(s):  
Interphase Nucleus ◽  
5S Rdna ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Meiotic Behavior ◽  
Meiotic Analysis ◽  
Chromosomal Pair ◽  
Cytogenetic Characterization

Since previous cytogenetic reports of Aloysia have only described the meiotic behavior and chromosomal number of some species, the aim of this work was to provide detailed cytogenetic description of Aloysia virgata that would contribute to the understanding of the taxonomical organization of the Verbenaceae. Aloysia virgata had a karyotype with 2n = 36 metacentric chromosomes, all with similar size. The large amount of heterochromatin seen after Giemsa staining was confirmed by C-banding. Four nucleolar organizer regions (NORs) were detected with an rDNA 45S probe in two homologous pairs and two sites of 5S rDNA located on one chromosomal pair were detected by fluorescence in situ hybridization. The interphase nucleus was classified as semi-reticulate. Meiotic analysis showed a normal chromosomal behavior, with 18 bivalents in some parts of prophase I and in metaphase I. The number of chromosomes, NORs and 5S rDNA segments did not exclude a possible polyploid origin.

Cyto-evolution of Boronia genomes revealed by fluorescent in situ hybridization with rDNA probes

Genome ◽  
2003 ◽  
Vol 46 (3) ◽  
pp. 507-513 ◽  
Author(s):  
Fucheng Shan ◽  
Guijun Yan ◽  
Julie A Plummer
Keyword(s):  
Fluorescent In Situ Hybridization ◽  
Diploid Species ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
26S Rdna ◽  
Rdna Sequences ◽  
Gene Copies ◽  
Rdna Sites ◽  
Rdna Copy

The physical location of the 25S–26S rDNA sequences was examined in 11 taxa of nine species of Boronia. In diploid species, two rDNA sites were detected in Boronia clavata (2n = 14), Boronia pinnata 'White' (2n = 22), and Boronia chartacea (2n = 32); four in Boronia megastigma (2n = 14) and Boronia denticulata (2n = 18); six in Boronia pinnata 'Pink' (2n = 22); and eight in Boronia molloyae (2n = 16). Eleven sites were found in Boronia heterophylla 'Red' and 'Near White' (2n = 15), but only two active nucleolar organizer regions (NORs) were observed. In polyploid species, Boronia pilosa (2n = 44) had four rDNA sites, while Boronia coerulescens (2n = 72) had six. Most of the rDNA sequences were terminal, but a few were interstitial. There were also differences in signal intensity indicating that the gene copies between and within rDNA sites might be different. The result suggests that considerable chromosome rearrangements have occurred during Boronia cyto-evolution, leading to variation among Boronia taxa in rDNA copy number, site number, and location. These changes together with dysploid reduction during cyto-evolution have made the Boronia genome considerably diverse in chromosome number, genome organization, and chromosome structure.Key words: physical mapping, FISH, chromosome, Rutaceae.

Comparative cytogenetics of four species of Thrichomys (Rodentia: Echimyidae)

Genome ◽  
2019 ◽  
Vol 62 (1) ◽  
pp. 31-41
Author(s):  
Naiara Pereira Araújo ◽  
Cibele Bonvicino ◽  
Marta Svartman
Keyword(s):  
Nucleolar Organizer ◽  
Interspecific Variation ◽  
Northeastern Brazil ◽  
Nucleolar Organizer Regions ◽  
Comparative Cytogenetics ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Robertsonian Rearrangements ◽  
Cytogenetic Analyses

Thrichomys Trouessart, 1880 is a genus of echimyid rodents endemic to South America, distributed from northeastern Brazil to Paraguay and Bolivia. Although all the recognized species of this genus have already been karyotyped, detailed comparative cytogenetic analyses have not been performed yet. We karyologically analyzed four species of Thrichomys from different Brazilian states. Our analyses included GTG- and CBG-banding, silver-staining of the nucleolar organizer regions (Ag-NORs), and fluorescent in situ hybridization (FISH) with telomeric and 45S rDNA probes. Comparative GTG-banding suggested that the interspecific variation may result from Robertsonian rearrangements, pericentric and paracentric inversions, centromere repositioning, and heterochromatin variation. FISH with a telomeric probe showed interspecies variation in interstitial telomeric sequences (ITs) distribution. Our results represent the most complete data on the cytogenetics of Thrichomys reported to date and give an insight into the chromosome evolution of this genus.

Structure and variability of nucleolar organizer regions in Parodontidae fish

1984 ◽  
Vol 26 (5) ◽  
pp. 564-568 ◽  
Author(s):  
Orlando Moreira-Filho ◽  
Luiz Antonio Carlos Bertollo ◽  
Pedro Manoel Galetti Jr.
Keyword(s):  
Chromosome Pair ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Mitotic Chromosomes ◽  
Homozygous Condition ◽  
Nucleolar Organizing Regions ◽  
Nucleolar Chromosome

Nucleolar organizer regions (NORs) were studied in mitotic chromosomes of four species of fish of family Parodontidae: Parodon tortuosus, Apareiodon affinis, Apareiodon ibitiensis, and Apareiodon piracicabae. All four species exhibited only a single nucleolar chromosome pair in their karyotypes. Intraspecific differences were observed in the size of these chromosomes; however, these were not very clear for A. affinis and A. piracicabae, Apareiodon piracicabae exhibited two clearly visible NORs in each of the nucleolar chromosomes, which was the only configuration practically found in this species. This trait therefore predominates in a homozygous condition in the population investigated. Regions of constitutive heterochromatin adjacent to the two NORs were detected. Possible mechanisms that may have originated the two NORs are discussed.Key words: nucleolar organizing regions, fish.

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.

scholarly journals Different Proliferation Patterns in Breast Cancer: AgNOR Measurements in ER-Negative and ER-Positive Tumor Cells

2000 ◽  
Vol 20 (4) ◽  
pp. 155-162 ◽  
Author(s):  
Lukas Günther ◽  
Peter Hufnagl ◽  
Klaus‐Jürgen Winzer ◽  
Hans Guski
Keyword(s):  
Breast Cancer ◽  
Tumor Cells ◽  
Nucleolar Organizer ◽  
Growth Fraction ◽  
Nucleolar Organizer Regions ◽  
Ki 67 ◽  
Er Positive ◽  
Negative Tumor ◽  
Invasive Breast Carcinomas

The relation between estrogen receptors (ER) and argyrophilic nucleolar organizer regions (AgNORs)in situwithin human breast cancer cells was analyzed. For AgNOR measurements in 49 invasive breast carcinomas, a new reproducible staining method for dual demonstration of ER and AgNORs was applied. Quantitative AgNOR variables were determined in ER‐positive and ER‐negative tumor cells by digital image analysis. The relationships between AgNOR parameters of ER‐positive and ER‐negative cells and other prognostic factors of breast cancer [Bloom–Richardson‐Grading and growth fraction (Ki‐67 index)] were investigated. A higher AgNOR content in ER‐negative cells and a special clustering phenomenon in ER‐positive tumor cells were found. Correlation with other criteria of malignant potential could be exclusively demonstrated for ER‐negative cells. ER‐negative cells of breast cancer can be characterized as the more malignant and possibly prognosis‐dictating cell fraction. Thus, ER‐negative cells probably contribute more to the progression of the tumor disease and furthermore to the prognosis than ER‐positive cells. We recommend measurement AgNORs exclusively in ER‐negative cells of breast cancer.

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