The B chromosomes of Locusta migratoria. III. Effects on the activity of nucleolar organizer regions

Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 387-394 ◽  
Author(s):  
F. Javier Salcedo ◽  
Esther Viseras ◽  
Juan Pedro M. Camacho
Keyword(s):  
Locusta Migratoria ◽  
Nucleolar Organizer ◽  
Cellular Level ◽  
B Chromosomes ◽  
Nucleolar Organizer Regions ◽  
Type I ◽  
Positive Dependence ◽  
Different Populations ◽  
The Mean ◽  
Genetic And Environmental Factors

Active nucleolus organizing regions (NORs) have been studied in two controlled crosses in the locust Locusta migratoria. NOR activity was detected in all the chromosomes of the standard complement but not in the B chromosomes. On the basis of both the frequency with which they are active and the size of the resulting nucleolus, NORs in this species can be classified in three groups: (i) type I primary NORs that are active in the majority of cells and give rise to large nucleoli; (ii) type II primary NORs that are active in the majority of cells but produce small nucleoli; and (iii) secondary NORS that are active in a minority of cells and yield small nucleoli. The presence of B chromosomes influences the mean activity of some NORs, particularly those giving rise to small nucleoli (groups ii and iii), although different populations yield contradictory results. Our findings indicate that NOR activity in L. migratoria is regulated by genetic and environmental factors, and can be influenced by the presence of B chromosomes which tend to increase the cellular level of NOR activity. An analysis of dependence between NORs for activity demonstrated the existence of a positive dependence between many of the NORs that give rise to small nucleoli. The presence of B chromosomes, however, favoured these enhancement relationships between nonhomologous NORs.Key words: Locusta, B chromosomes, nucleolar organizer.

p53 and bcl-2 expression and argyrophilic nucleolar organizer regions in patients with malignant maxillary sinus tumours

1997 ◽  
Vol 111 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Torahiko Nakashima ◽  
Tadashi Nakashima ◽  
Muneyuki Masuda ◽  
Sohtaro Komiyama
Keyword(s):  
Maxillary Sinus ◽  
Clinical Course ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Malignant Tumours ◽  
Clinicopathological Findings ◽  
Significant Difference ◽  
The Mean ◽  
Maxillary Tumours ◽  
Argyrophilic Nucleolar Organizer Regions

AbstractTo investigate the relation between the clinicopathological findings, and the survival of patients with malignant tumours of the maxillary sinus, and the tumour's biological parameters, we examined the expression of p53 and bcl-2 and the number of silver-stainable nucleolar organizer regions (AgNORs) in 23 paraffin-embedded specimens from primary tumours. Fifteen of 23 (65 per cent) maxillary tumours expressed p53 and two of 23 (nine per cent) tumours expressed the bcl-2 gene product. The mean number of AgNORs per nucleus was 5.2 ± 2.4. There was no relationship between the expression of p53 or bcl-2 and the patient's clinical course. In contrast, there was a statistically significant difference in the survival of patients with a high (>6) number of AgNORs and patients with a low (<6) number of AgNORs. These data suggest that the number of AgNORs may be useful in evaluating the prognosis of patients with malignant maxillary sinus tumours.

scholarly journals Preliminary investigation on the variation of the nucleolar organizer region in the breeding chinchilla karyotype

2016 ◽  
Vol 72 (6) ◽  
pp. 373-377 ◽  
Author(s):  
Marta Kuchta-Gładysz ◽  
Agnieszka Otwinowska-Mindur ◽  
Piotr Niedbała ◽  
Olga Szeleszczuk ◽  
Joanna Głowacka
Keyword(s):  
Silver Staining ◽  
Organizer Region ◽  
Preliminary Investigation ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Silver Deposit ◽  
Nor Polymorphism ◽  
The Mean ◽  
Class Iv

The objective of this study was to determine the variation in the number and size of nucleolar organizer regions (NOR) in the chinchilla karyotype. The study was performed with 12 standard chinchillas of two different lines. NORs were visualized on chromosome preparations by Ag-NOR silver staining. Four NOR size classes (I-IV) were determined on the basis of the results obtained, ranging from 0.070 (class I) to 0.229 (class IV). The mean NOR size was 0.144 µm² (SD=0.031 µm²) and fell within class II (from 0.101 to 0.150 µm²). Differences in the relative silver deposit area between the NOR-bearing pair of chromosomes were significant for 3 animals (P < 0.01) and for 1 animal (P < 0.05). The mean number of NORs in the animals ranged from 1.4 to 2.0 (SD=0.00–0.55). It was lower for chinchillas from central Poland (1.53±0.50) compared to those from southern Poland (1.68±0.48), with no significant differences (P > 0.05). The variation observed in the NOR size and number in the chinchilla karyotype indicates the occurrence of NOR polymorphism in the population.

scholarly journals Usefulness of argyrophilic nucleolar organizer regions in detection of lung cells alterations after benzo[a]pyrene instillation

2006 ◽  
Vol 21 (suppl 4) ◽  
pp. 36-39 ◽  
Author(s):  
Baldomero Antonio Kato da Silva ◽  
Iandara Schettert Silva ◽  
Daniel Martins Pereira ◽  
Ricardo Dutra Aydos ◽  
Paulo de Tarso Camillo de Carvalho
Keyword(s):  
Statistical Tests ◽  
Nucleolar Organizer ◽  
Lung Cells ◽  
Nucleolar Organizer Regions ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean ◽  
Pulmonary Instillation ◽  
The Relationship ◽  
Argyrophilic Nucleolar Organizer Regions

PURPOSE: To verify the relationship between AgNOR expression and lung tissues changes of Wistar rats after pulmonary instillation of benzo[a]pyrene (B[a]P). METHODS: Male Rattus norvegicus albinus,Wistar lineage were given a single intrapulmonary instillation of B[a]P at doses of 10 and 20 mg/kg in a volume of approximately 0,3 ml. After 7 and 21 days the rats were killed and the lung slices submitted to a histological technique of AgNOR. AgNOR dots were quantified and the result analyzed by statistical tests; p <= 0,05 was considered significant. RESULTS: The mean values of AgNOR dots for the experimental groups 10/7 (1,51±0,86) and 10/21 (1,84±0,13) were statistically different (p = 0,009). Among the groups 20/7 (1,63±0,11) and 20/21 (2,48±0,28) was observed statistically significant difference (p = 0,003). CONCLUSION: The AgNOR technique can be useful in identification of cells changes induced by B[a]P.

Nucleolar organizer regions in various human brain tumors

1991 ◽  
Vol 74 (6) ◽  
pp. 979-984 ◽  
Author(s):  
Tetsuya Shiraishi ◽  
Kazuo Tabuchi ◽  
Toshihiro Mineta ◽  
Nobuaki Momozaki ◽  
Masashi Takagi
Keyword(s):  
Brain Tumors ◽  
Human Brain ◽  
Nucleolar Organizer ◽  
Staining Technique ◽  
Nucleolar Organizer Regions ◽  
Proliferative Potential ◽  
High Grade ◽  
Content Type ◽  
The Mean ◽  
Fine Print

✓ Nucleolar organizer regions (NOR's) are loops of deoxyribonucleic acid (DNA) which transcribe to ribosomal ribonucleic acid (RNA) by RNA polymerase I. They possess vital significance in the ultimate synthesis of cellular proteins. A silver colloid staining technique for demonstration of NOR-associated proteins (Ag-NOR's) was applied to paraffin-embedded sections from 128 varied brain tumors and to chromosomal preparations from cultured brain-tumor cells. There was a statistically significant difference in the mean number of Ag-NOR's per nucleus between low-grade tumors (1.98/nucleus) and high-grade tumors (2.95/nucleus). It is suggested that the mean number of Ag-NOR's may represent the proliferative potential of brain tumors. Furthermore, high-grade tumors usually showed relatively large Ag-NOR's in a scattered distribution. In chromosomal preparations, the cultured cells displayed five to 12 Ag-NOR's on acrocentric chromosomes. Five of eight cell lines examined demonstrated ectopic Ag-NOR's. This simple staining technique can be easily applied to routinely processed paraffin-embedded sections and will become a useful tool for quick estimation of the proliferative potential of human brain tumors.

The B chromosomes of Locusta migratoria. II. Effects on chiasma frequency

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 118-123 ◽  
Author(s):  
Esther Viseras ◽  
F. Javier Salcedo ◽  
Juan Pedro M. Camacho
Keyword(s):  
Environmental Factors ◽  
Genetic Relationship ◽  
Chiasma Frequency ◽  
Locusta Migratoria ◽  
B Chromosomes ◽  
A Cell ◽  
Genetic And Environmental Factors ◽  
Close Genetic Relationship ◽  
Accessory Chromosomes

The effects of accessory chromosomes of Locusta migratoria have been tested at intra- and inter-individual levels. Intraindividual analysis demonstrated that chiasma frequency of a cell is independent of the number of B-chromosomes that it contains. Interindividual analysis was done using males with a close genetic relationship (brother–brother and father–son) as well as males not showing such relationship. This analysis demonstrated the importance of both genetic and environmental factors in determining chiasma frequency. It was concluded that B chromosomes have no influence on this character.Key words: Locusta, B chromosomes, chiasma frequency.

scholarly journals The Polymorphism of Cytogenetic Markers in the Farm and Wild-Living Raccoon Dog (Nyctereutes Procyonoides) / Polimorfizm Markerów Cytogenetycznych U Jenota (Nyctereutes Procyonoides) W Populacjach Hodowlanych I Dziko Żyjących

2013 ◽  
Vol 13 (4) ◽  
pp. 701-713 ◽  
Author(s):  
Monika Bugno-Poniewierska ◽  
Mariusz Wroński ◽  
Leszek Potocki ◽  
Klaudia Pawlina ◽  
Maciej Wnuk ◽  
...  
Keyword(s):  
Mammalian Species ◽  
Molecular Cytogenetics ◽  
Nucleolar Organizer ◽  
Variable Number ◽  
B Chromosomes ◽  
Farm Animals ◽  
Nucleolar Organizer Regions ◽  
Nyctereutes Procyonoides ◽  
Raccoon Dog ◽  
Basic Set

Abstract The raccoon dog (Nyctereutes procyonoides) is a mammalian species that belongs to Canidae family, order Carnivora. This species represents both animals living in the wild and farm animals used in the fur industry. Raccoon dogs have the most ‘primitive’ karyotype among Canidae family. The Chinese raccoon dog (Nyctereutes procyonoides procyonoides) is characterised by a variable number of chromosomes (2n = 54 + 0-4 B). B chromosomes are supernumerary chromosomes occurring in addition to the basic set of A chromosomes in the cells of many organisms. The function and origin of these additional chromosomes is not clear. The aim of this work was to determine possible karyotypic differences between wild-living and farm populations, using methods of classical and molecular cytogenetics. The most useful cytogenetic markers to analyse karyotype polymorphism of canine are the number of B chromosomes and nucleolar organizer regions. A variation was identified in the number of B chromosomes and nucleolar organizer regions (NORs) in cells between wild-living and breeding populations.

scholarly journals Analysis of the Proliferative Potential of Odontogenic Epithelial Cells of Pericoronal Follicles

2014 ◽  
Vol 15 (6) ◽  
pp. 761-765
Author(s):  
Natalia Cimadon ◽  
Isabel Silva Lauxen ◽  
Vinicius Coelho Carrard ◽  
Manoel Sant'Ana Filho ◽  
Pantelis Varvaki Rados ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Descriptive Analysis ◽  
Nucleolar Organizer ◽  
Enamel Organ ◽  
Nucleolar Organizer Regions ◽  
Proliferative Potential ◽  
Ki 67 ◽  
Impregnation Technique ◽  
Odontogenic Epithelium ◽  
The Mean

ABSTRACT Aim To evaluate the proliferative potential and the cell proliferation rate of odontogenic epithelial cells. Materials and methods Forty-two cases of pericoronal follicles of impacted third molars were submitted to silver impregnation technique for quantification of argyrophilic nucleolar organizer regions (AgNOR) and immunohistochemical staining for EGFR and Ki-67. For AgNOR quantification, the mean number of active nucleolar organizer regions per nucleus (mAgNOR) and the percentage of cells with 1, 2, 3 and 4 or more AgNORs per nucleus (pAgNOR) were quantified. Ki-67 immunolabeling was quantified, whereas for EGFR, a descriptive analysis of staining patterns (membrane, cytoplasm or membrane + cytoplasm positivity) was performed. We evaluated the reduced epithelium of the enamel organ and/or islands of odontogenic epithelium present in the entire connective tissue. Results mAgNOR were 1.43 (1.0-2.42) and were significantly different among pericoronary follicles from upper and lower teeth (p = 0.041). Immunostaining of Ki-67 was negative in all cases. EGFR immunolabeling was found mainly in the cytoplasm and was more intense in islands and cords when compared to reduced epithelium of the enamel organ. Conclusion Odontogenic epithelial cells of some pericoronal follicles have proliferative potential, suggesting their association with the development of odontogenic lesions. Clinical significance The authors suggest that nonerupted, especially of the lower teeth, should be monitored and if necessary removed. How to cite this article Cimadon N, Lauxen IS, Carrard VC, Filho MSA, Rados PV, Oliveira MG. Analysis of the Proliferative Potential of Odontogenic Epithelial Cells of Pericoronal Follicles. J Contemp Dent Pract 2014;15(6):761-765.

Electron Microscopic investigation of crooke’s change in the pituitaries of patients with hypercorticism

1989 ◽  
Vol 47 ◽  
pp. 848-849
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
L. Stefaneanu ◽  
N. Losinski
Keyword(s):  
Nucleolar Organizer ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Ectopic Acth Syndrome ◽  
Nucleolar Organizer Regions ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Ectopic Acth ◽  
Crooke’S Hyalinization

Human pituitary corticotropins have unique morphologic markers: bundles of type-1 filaments, measuring approximately 70 A in width and representing cytokeratin. The extreme ring-like accumulation of type-1 filaments, known as Crooke's hyalinization, signals functional suppression of the corticotropins and occurs in endogenous and exogenous glucocorticoid excess, caused by ACTH-secreting pituitary adenoma, glucocorticoid secreting adrenocortical tumor, ectopic ACTH-syndrome and administration of pharmacologic doses of glucocorticoids. Cells of autonomous corticotroph adenomas usually do not show Crooke's hyalin change. A minority of these tumors, however, retains sensitivity to the negative feed-back effect of elevated blood glucocorticoid levels and display typical Crooke’s change.In the present study pituitary corticotropins in various phases of Crooke's hyalinization were investigated in patients with glucocorticoid excess of various origin, applying histology, immunocytochemistry, count of argyrophilic nucleolar organizer regions (AgNOR), and transmission electron microscopy.

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.

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