scholarly journals A comparative chromosome study on five Minnow fishes (Cyprinidae, Cypriniformes) in Thailand

Caryologia ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 89-96
Author(s):  
Surachest Aiumsumang ◽  
Sumalee Phimphan ◽  
Chatmongkon Suwannapoom ◽  
Patcharaporn Chaiyasan ◽  
Weerayuth Supiwong ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Nucleolar Organizer ◽  
Subtelomeric Region ◽  
Diploid Chromosome Number ◽  
Chromosome Study ◽  
Banding Technique ◽  
Nucleolar Organizer Regions ◽  
Renal Cells ◽  
Mitotic Chromosomes ◽  
Acrocentric Chromosomes

The cytogenetic comparisons of five Minnow species from Thailand were presented here, i.e., Devario regina, D. laoensis, Rasbora paviana, R. aurotaenia and Esomus metalicus. The mitotic chromosomes were prepared directly from renal cells. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosomes. The results revealed that all Minnow fishes studied possessed the same diploid chromosome number (2n) as 50 chromosomes. The fundamental numbers (NF) of D. laoensis, D. regina, R. paviana, R. aurotaenia and E. metalicus are 100, 100, 98, 98, and 98 respectively. Their karyotypes composing of metacentrics-submetacentrics-acrocentrics-telocentrics were as follows: 6-12-32-0 in D. regina, 6-10-34-0 in D. laoensis, 8-16-24-2 in R. paviana, 8-16-24-2 in R. aurotaenia and 8-10-30-2 in E. metalicus. The Ag-NOR banding technique provides the nucleolar organizer regions (NORs) at subtelomeric region of the short arm chromosome in the a submetacentric or acrocentric chromosomes that are located differently in the different chromosome pairs among species. 

Note on the karyotype and NOR phenotype of leuciscine fish Acanthobrama marmid (Osteichthyes, Cyprinidae)

Biologia ◽  
2006 ◽  
Vol 61 (2) ◽  
Author(s):  
Muhammet Gaffaroglu ◽  
Esref Yuksel ◽  
Petr Ráb
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
Silver Staining ◽  
Chromosome Pair ◽  
Nucleolar Organizer ◽  
Cyprinid Fish ◽  
Nucleolar Organizer Regions ◽  
Heteromorphic Sex Chromosomes ◽  
Nor Phenotype ◽  
Acrocentric Chromosomes

AbstractThe karyotype and major ribosomal sites as revealed using silver staining of Anatolian leuciscine cyprinid fish Acanthobrama marmid were studied. The diploid chromosome number was invariably 2n = 50. Karyotype consisted of eight pairs of metacentric, 13 pairs of submetacentric and four pairs of subtelocentric to acrocentric chromosomes. The largest chromosome pair of the complement was subtelo-to acrocentric characteristically, which is a characteristic cytotaxonomic marker for representatives of the cyprinid lineage Leuciscinae. The nucleolar organizer regions (NORs) were detected in the telomeres of two pairs of medium sized submeta-to subtelocentric chromosomes. No heteromorphic sex chromosomes were found. The karyotype pattern of A. marmid is nearly identical to that found in most other representatives of the Eurasian leuciscine cyprinids, while the multiple NOR phenotype appears to be more derived as opposed to a uniform one, ubiquitous in this group.

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.

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.

The mitotically phosphorylated form of the transcription termination factor TTF-1 is associated with the repressed rDNA transcription machinery

1999 ◽  
Vol 112 (19) ◽  
pp. 3259-3268 ◽  
Author(s):  
V. Sirri ◽  
P. Roussel ◽  
D. Hernandez-Verdun
Keyword(s):  
Transcription Termination ◽  
Nucleolar Organizer ◽  
Ribosomal Gene ◽  
Nucleolar Organizer Regions ◽  
Rdna Transcription ◽  
Mitotic Chromosomes ◽  
Termination Factor ◽  
Transcription Machinery ◽  
Phosphorylated Form ◽  
Transcription Termination Factor

The transcription termination factor TTF-1 exerts two functions in ribosomal gene (rDNA) transcription: facilitating initiation and mediating termination of transcription. Using HeLa cells, we show that TTF-1 protein is colocalized with the active transcription machinery in the nucleolus and also with the inactive machinery present in certain mitotic nucleolar organizer regions (NORs) when rDNA transcription is repressed. We also show that TTF-1 is specifically phosphorylated during mitosis in a manner dependent on the cdc2-cyclin B kinase pathway and on an okadaic acid-sensitive phosphatase. Interestingly, the mitotically phosphorylated form of TTF-1 appearing at the G(2)/M transition phase was more easily solubilized than was the interphase form. This indicates that the chromatin-binding affinity of TTF-1 appears to be different in mitotic chromosomes compared to the interphase nucleolus. Correlated with this, the other DNA-binding factor, UBF, which interferes with chromatin conformation in the rDNA promoter, was more strongly bound to rDNA during mitosis than at interphase. The reorganization of the mitotic rDNA promoter might be induced by phosphorylation of certain components of the rDNA transcription machinery and participate in silencing of rDNA during mitosis.

Chromosome differentiation in the subantarctic Bovichtidae species Cottoperca gobio (Günther, 1861) and Pseudaphritis urvillii (Valenciennes, 1832) (Pisces, Perciformes)

1995 ◽  
Vol 7 (4) ◽  
pp. 381-386 ◽  
Author(s):  
Eva Pisano ◽  
C. Ozouf-Costaz ◽  
J-C. Hureau ◽  
R. Williams
Keyword(s):  
Constitutive Heterochromatin ◽  
Chromosomal Location ◽  
Cytogenetic Study ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Chromosome Differentiation ◽  
Fundamental Number ◽  
Magellan Strait ◽  
Australian Plate ◽  
Acrocentric Chromosomes

A cytogenetic study on the bovichtid species Cottoperca gobio from the Magellan Strait and Pseudaphritis urvillii from Tasmania showed both species have a plesiomorphic number of chromosomes (2n=48). However, C.gobio has a more conservative karyotype composed entirely of acrocentric chromosomes (Fundamental Number=48); the presence of two metacentric pairs in P. urvilli (FN=52) makes this species karyologically more derived. The differences in the number of chromosomal arms, and the chromosomal location of the nucleolar organizer regions indicate karyological divergence in the two separating stocks from which C.gobio and P.urvillii originated. During the diversification of this notothenioid family, probably coincident with the fragmentation of Gondwana, the stock that split off with the Australian Plate gave rise to the Tasmanian species and experienced more chromosomal modifications than the stock from which C. gobio is derived. The pattern of constitutive heterochromatin suggests a possible homology between a pair of chromosomes in bovichtids and other notothenioids.

scholarly journals In vitro Callogenesis and Organogenesis from Carolina Reaper (Syn. Capsicum Chinense Jacq.) and Chromosomal Analysis

2020 ◽  
pp. 1-11
Author(s):  
Bruno Henrique Gomes ◽  
Fabrícia de Matos Oliveira ◽  
Ana Paula Oliveira Nogueira ◽  
Robson Jose de Oliveira Júnior
Keyword(s):  
Chromosome Number ◽  
Present Report ◽  
Good Condition ◽  
Nucleolar Organizer ◽  
Optical Microscope ◽  
Nodal Segments ◽  
Nucleolar Organizer Regions ◽  
Stem Segment ◽  
Meristematic Tissue

Aims: The aim of this paper is to develop an in vitro organogenesis and callogenesis protocol for Carolina Reaper pepper, and to determine the karyotype and nucleoli of this cultivar. Methodology: The MS medium with supplemented with indole-3-butyric (0, 1, 2 and 4 mg L-1) and kinetin (0, 1, 2 and 4 mg L-1) was used. The leaves and nodal segments of Carolina reaper was utilized for the callogenesis and organogenesis induction. The responses to growth regulators were evaluated 30 days of cultivation. The meristematic tissue was pre-treated with 0.05% (w/v) of colchicine for six hours at 18°C. The samples were fixed in Carnoy for 12 hours. Chromosomal observations were made with binocular optical microscope (Leica DM 750) and the cells in good condition for counting the chromosomes and karyotype assembly were photographed. Results were presented as mean ± standard deviation and were compared by the two-way Analysis of Variance. The means were separated according to Tukey test (P = 0.05). Results: Calli were induced from both leaf and stem segments when indole-3-butyric 0 mg L-1 + kinetin 1 mg L-1 were used. Development of shoots in leaf and stem segment were obtained when indole-3-butyric 2 mg L-1 + kinetin 4 mg L-1 were used, and roots regenerated with indole-3-butyric 4 mg L-1 + kinetin 1 mg L-1. It was found two nucleoli in every cell interphase, suggesting that two nucleolar organizer regions are expressing their ribosomal genes. Karyotype analysis indicated a chromosome number of 2n = 24, which is correlation with other Capsicum genus varieties. It was observed 1 or 2 nucleoli per nucleus of both types, homomorphic and heteromorphic. The results can help in programs of breeding and conservation of this cultivar and other species of pepper. Conclusion: Using the concentrations of growth hormones indicated in the present report, it could be possible to regenerate leaves and nodal segments in vitro clones from the original genotype. We have also described the chromosome number and nucleolus number of Carolina reaper, generating a data that could help in programs of breeding, as in the generation of polyploid plants and conservation species of pepper.

scholarly journals The First Karyological Analysis of the Sixbar Grouper Epinephelus sexfasciatus (Valenciennes, 1828) (Perciformes, Epinephelinae)

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Puan Pengseng ◽  
Keyword(s):  
Nucleolar Organizer ◽  
Andaman Sea ◽  
Banding Technique ◽  
Size Difference ◽  
Nucleolar Organizer Regions ◽  
Single Pair ◽  
Telocentric Chromosome ◽  
Karyotypic Analysis ◽  
Fish Samples ◽  
Southern Thailand

This study examines for the first time of karyotypic analysis and chromosomal characteristic of nucleolar organizer regions/NORs of Epinephelus sexfasciatus. The fish samples were collected from Andaman Sea, Phuket province, southern Thailand. The chromosomes were investigated using conventional Giemsa’s staining and Ag-NORs banding techniques. Fish chromosome preparations were conducted by squash technique from kidney. The results showed that the diploid chromosome number of E. sexfasciatus was 2n=48 and the fundamental number (NF, number of chromosome arms) was 48. The type of chromosomes included 24 large telocentric and 24 medium telocentric chromosomes. After Ag-NOR banding technique, single pair of NORs was observed on the short arm of medium telocentric chromosome pair 23. The idiogram shows gradually decreasing length of the chromosomes. A size difference of the largest and the smallest chromosomes is approximately two folds. The karyotype formula could be infered as: 2n(48) = 2n(48)= Lt24+Mt24.

scholarly journals Diversity and chromosomal evolution in the genus Ancistrus Kner, 1854 (Loricariidae: Ancistrini) from three hydrographic basins of Mato Grosso State, Brazil

2013 ◽  
Vol 11 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Sandra Mariotto ◽  
Liano Centofante ◽  
Orlando Moreira-Filho
Keyword(s):  
Diploid Number ◽  
Nucleolar Organizer ◽  
Single Species ◽  
Chromosomal Evolution ◽  
Nucleolar Organizer Regions ◽  
Mitotic Chromosomes ◽  
Evolutionary Mechanisms ◽  
Mato Grosso ◽  
Silver Nitrate Staining ◽  
Cytogenetic Analyses

Cytogenetic analyses were carried out in 117 specimens of seven species of the genus Ancistrus from three hydrographic in Mato Grosso State: Paraguay, Araguaia-Tocantins and Amazon basins. Conventional cytogenetic techniques were used to obtain mitotic chromosomes. C-banding was performed to detect heterochromatic regions and silver nitrate staining was used to identify nucleolar organizer regions (Ag-NORs). The counted and paired chromosomes revealed diploid numbers ranging from 2n = 40 to 2n = 54 with karyotype formulae varying from FN = 80 to FN = 86. Single marks in distinct chromosomes identified the nucleolar organizer regions. The constitutive heterochromatin was scarce in the diploid number from 2n = 50 to 2n = 54 and conspicuous blocks were observed in a single species with 2n = 40 chromosomes. These data corroborate the hypotheses of reduction of diploid number in species with derived features such as presence of sex chromosomes and polymorphisms, besides allowing inferences about the evolutionary mechanisms and the ancestor karyotype that favored the diversification of this important genus in the tribe Ancistrini.

scholarly journals NORs on human acrocentric chromosome p-arms are active by default and can associate with nucleoli independently of rDNA

2020 ◽  
Vol 117 (19) ◽  
pp. 10368-10377
Author(s):  
Marjolein van Sluis ◽  
Chelly van Vuuren ◽  
Hazel Mangan ◽  
Brian McStay
Keyword(s):  
Cell Lines ◽  
Ribosome Biogenesis ◽  
Chromosomal Rearrangements ◽  
Three Dimensional ◽  
Nucleolar Organizer ◽  
Factor Loading ◽  
Interindividual Variation ◽  
Nucleolar Organizer Regions ◽  
Metaphase Chromosomes ◽  
Acrocentric Chromosomes

Nucleoli, the sites of ribosome biogenesis and the largest structures in human nuclei, form around nucleolar organizer regions (NORs) comprising ribosomal DNA (rDNA) arrays. NORs are located on the p-arms of the five human acrocentric chromosomes. Defining the rules of engagement between these p-arms and nucleoli takes on added significance as describing the three-dimensional organization of the human genome represents a major research goal. Here we used fluorescent in situ hybridization (FISH) and immuno-FISH on metaphase chromosomes from karyotypically normal primary and hTERT-immortalized human cell lines to catalog NORs in terms of their relative rDNA content and activity status. We demonstrate that a proportion of acrocentric p-arms in cell lines and from normal human donors have no detectable rDNA. Surprisingly, we found that all NORs with detectable rDNA are active, as defined by upstream binding factor loading. We determined the nucleolar association status of all NORs during interphase, and found that nucleolar association of acrocentric p-arms can occur independently of rDNA content, suggesting that sequences elsewhere on these chromosome arms drive nucleolar association. In established cancer lines, we characterize a variety of chromosomal rearrangements involving acrocentric p-arms and observe silent, rDNA-containing NORs that are dissociated from nucleoli. In conclusion, our findings indicate that within human nuclei, positioning of all 10 acrocentric chromosomes is dictated by nucleolar association. Furthermore, these nucleolar associations are buffered against interindividual variation in the distribution of rDNA.

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