The organizer is established at the blastula stage of development, under the influence of a special region of cells known as the Nieuwkoop center in amphibians, where Vg1/activin-like signals overlap with activity of the Wnt-pathway. Despite differences in their mode of early development, a similar region can be identified in other vertebrates. It has widely been assumed that once the organizer...

The chromosomal banding properties of Oxynoemacheilus simavicus (Balık & Bănărescu, 1978) were revealed out by C-banding and silver staining. Constitutive heterochromatin regions determined on the pericentromeres most chromosomes C-banding. Otherwise, nucleolus organizer (NORs) observed short (p) arms one middle-sized submetacentric (sm) chromosome pair Also, Ag-NOR size number polymorphism...

Trisomy mapping is a powerful method for assigning genes to chicken microchromosome 16 (GGA 16). The single chicken nucleolar organizer region (NOR), the 2 major histocompatibility complex regions (MHC-Y and MHC-B), and CD1 genes were all previously assigned to GGA 16 using trisomy mapping. Here, we combined array comparative genomic hybridization with trisomy mapping to screen unassigned genom...

Material and Methods: The present study was conducted on 40 specimens of breast carcinoma out of which 12 cases were of Grade II and 28 cases were of Grade III. Percentage positivity and scoring of Ki-67 and mean AgNOR count was done with relation to grades. Observations: Ki-67 positivity was seen in 12 cases with the percentage positivity of 2.33±5.516 in grade II and 9.67±7.671 in grade III t...

The use of Toombak has been reported to play a major role in the etiology of oral cancer in Sudan. The cellular proliferative activity on the oral epithelium of 210 Toombak dippers was assessed by applying the micronuclei frequency, mean argyrophilic nucleolar organizer region (AgNOR) counts, Papanicolaou method, and 1% crystal violet stain. Participants were divided into 3 groups: 200 were app...

The chromosome complement of Chiropodomys gliroides from Peninsular Malaysia consists of two pairs of nucleolar organizer regions (NORs) – the longest acrocentric pair and the small metacentric. The NORs in both pairs are located at the terminal end; in the long acrocentric at the end of the long arm. In the metaphases, at least one element in both pairs exhibited the presence of Ag-NOR activit...

Loricariidae is one of the largest fish families of the world, with about 650 species separated into six subfamilies. To date, cytogenetic data on only 56 species of this family are available. In the present study, the karyotypes of three Ancistrinae species and five Loricariinae species were studied. The lowest diploid number, 2n=38, was observed in Ancistrus n.sp. 1 (Ancistrinae) and the high...

Tissue markers of cellular proliferatian have been recently utilized as prognostic indicators in brain tumors. Nudeolar organizer regions (NORs)are loops of deoxyribonudeic add (DNA) that transcribe to ribosomal ribonudeic acid (RNA) by RNA polymerase i. Using asilver staining technique. nudeolar organizer region-assodated proteins (AgNORs) have been studied in paraffin sections of 62 meningeal...

During zebrafish development, zygotic gene expression initiated at the midblastula transition converts maternal information on embryo polarity into a transcriptional read-out. Expression of a homeobox gene, vega1, is activated at midblastula transition in all blastomeres, but is down-regulated dorsally before gastrulation. Ubiquitous expression of vega1 is maintained in bozozok mutants, in whic...

Argyrophilic nucleolar organizer regions (AgNORs) were determined in 94 pleural, pericardial and peritoneal effusions. The results were correlated with cytologic diagnosis to determine the diagnostic potential of this technique. Cytologically the number of normal, reactive and malignant effusions were 32, 28 and 34 respectively. The mean AgNOR counts for normal, reactive and malignant spec...