Cytogenetics of Zaprionus indianus Gupta (Diptera: Drosophilidae): Nucleolar organizer regions, mitotic and polytene chromosomes and inversion polymorphism

Genetica ◽  
1987 ◽  
Vol 74 (1) ◽  
pp. 19-25 ◽  
Author(s):  
J. P. Gupta ◽  
A. Kumar
Keyword(s):  
Polytene Chromosomes ◽  
Nucleolar Organizer ◽  
Inversion Polymorphism ◽  
Nucleolar Organizer Regions ◽  
Zaprionus Indianus ◽  
And Inversion

scholarly journals Karyotype and inversion polymorphism of natural populations Glyptotendipes glaucus (meigen), 1818 (diptera, chironomidae) from the small reservoirs of Kaliningrad

2016 ◽  
Vol 14 (4) ◽  
pp. 41 ◽  
Author(s):  
Natalia V Vinokurova ◽  
Evgeniya A Kalinina ◽  
Edgar E Stol’
Keyword(s):  
Polytene Chromosomes ◽  
Natural Populations ◽  
Chromosomal Polymorphism ◽  
Inversion Polymorphism ◽  
Toxic Substances ◽  
Widespread Species ◽  
Almost All ◽  
And Inversion ◽  
The Impact ◽  
Glyptotendipes Glaucus

Background. A larvae of family Chironomidae are the most mass and widespread species of macrozoobenthos and play an important role in the lives of almost all types of reservoirs. They constitute a convenient model in the analysis of anthropogenic influences. Besides, chironomids have the largest polytene chromosomes in nature that allow carrying out cytogenetic analysis of the impact of various toxic substances on chromosomal aberrations. Materials and methods. The karyotype and chromosomal inversion polymorphism one of the species phytophilic chironomids Glyptotendipes glaucus (Meigen, 1818) from five reservoirs of Kaliningrad (ponds Chistyi and Mel’nichnyi, system of ponds Karasevka, lakes Pen’kovoe and Shkol’noe) was studied. Cytological mapping of chromosomes was performed by system of Belyanina and Durnova (1998). Results. The levels of natural inversion polymorphism for each populations were determined. Comparison of inversion polymorphism with early data for Saratov, Bryansk and Kaliningrad regions was carried. The preservation of tendencies of distribution and prevalence gomo-and heterozygotic inversions of glaB1.2, glaB2.2 and also consolidation in the karyofund of populations sequence glaA2 in the heterozygous state in ponds Karasevka and Chistyi was observed. The characteristic for an earlier research of populations Glyptotendipes glaucus of Kaliningrad the presence inversion sequences glaG4 and glaD2 is retained. The level of inversion polymorphism for reservoirs of Kaliningrad has decreased and has approached nearer to data for Bryansk and Saratov regions. Conclusion. Based on these results we can offer a working hypothesis of a direct dependence of value of chromosomal polymorphism on the level of pollution of reservoirs ions of heavy metals (Kaliningrad), long-living radionuclides (Bryansk region), nitrates and ions of ammoniac nitrogen (Saratov region).

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.

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.

Increased Nucleolar Organizer Regions in Osteoclast Nuclei of Paget’s Bone Disease

Bone ◽  
1998 ◽  
Vol 22 (1) ◽  
pp. 45-49 ◽  
Author(s):  
D. Chappard ◽  
N. Retailleau/Gaborit ◽  
R. Filmon ◽  
M. Audran ◽  
M.-F. Baslé
Keyword(s):  
Bone Disease ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Paget’S Bone Disease ◽  
Paget's Bone Disease

scholarly journals Phase specific Ag-staining of nucleolar organizer regions (NORs) and kinetochores in the Australian ant Myrmecia croslandi.

1992 ◽  
Vol 67 (6) ◽  
pp. 437-447 ◽  
Author(s):  
Hirotami T. IMAI ◽  
Hirohisa HIRAI ◽  
Yoko SATTA ◽  
Toshihiko SHIROISHI ◽  
Masaaki YAMADA ◽  
...  
Keyword(s):  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions
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