The specification of neuronal cell types in the developing neural tube is orchestrated by signaling centers. However, how patterned territories of the central nervous system (CNS) are organized into structures with appropriate size and shape is still unclear. We report that in the absence of the mouse transcription factor mBtd/Sp8, a posterior shift of the isthmic organizer (IsO) occurs, sugges...

Annual fish which belong to the order Cyprinodontiformes constitute an excellent model for evolutionary studies. their short life cycle, distribution in ecologically dynamic environments, and low agility make them favorable for genetic analyses. The species Hypsolebias antenori (Rivulidae), encountered in seasonal pools located in the semiarid region of Northeastern Brazil, has been the object ...

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...

The prognostic significance of AgNOR proteins in stage II-III rectal cancers treated with chemoradiotherapy was evaluated. Silver staining was applied to the 3μm sections of parafin blocked tissues from 30 rectal cancer patients who received 5-FU based chemoradiotherapy from May 2003 to June 2006. The microscopic displays of the cells were transferred into the computer via a video camera. AgNOR...

The influence of conditions resulting in bobbed phenotypes on nucleolar RNA synthesis and the formation of constrictions at nucleolus organizers was examined in larval tissues of Drosophila melanogaster. By means of [H]uridine incorporation and autoradiographic analysis, a mutation at the bobbed locus was shown to limit the rate of nucleolar RNA synthesis in salivary glands of XO larvae. The fo...

Mullets are very common fishes included in the family Mugilidae, (Mugiliformes), which are characterized by both a remarkably uniform external morphology and internal anatomy. Recently, within this family, different species complexes were molecularly identified within Mugil, a genus which is characterized by lineages that sometimes show very different karyotypes. Here we report the results of c...

The ribosomal DNA (DNA complementary to ribosomal RNA) content of twelve different wheat genotypes has been studied. Some of these genotypes are aneuploids with deletions or additions of chromosomes bearing nucleolar organisers. The rDNA contents of these genotypes provide several examples of a clear departure from a correlation between the number of rRNA cistrons and the number of nucleolar or...

Argyrophilic nucleolar organiser regions (AgNORs) in 28 follicular lymphomas and 30 lymph nodes showing reactive follicular hyperplasia were studied to see if they were helpful in distinguishing follicular lymphoma from follicular hyperplasia in paraffin wax tissue sections. Mean nuclear counts were greater in follicular hyperplasia (3.71 v 3.11). This difference was significant but counts over...