Cytogenetic studies were carried out on samples of Parapteronotus hasemani, Sternarchogiton preto and Sternarchorhamphus muelleri (Apteronotidae, Gymnotiformes) from the Amazon basin. The first two species exhibited both a 2n = 52 karyotype, but differed in their karyotypic formulae, distribution of constitutive heterochromatin, and chromosomal location of the NOR. The third species, Sternarcho...

One of the biggest challenges in studying how genes work is understanding their effect on the physiology and anatomy of the body. Existing tools try to address this using indirect features, such as expression levels and biochemical pathways. Here, we present Gene ORGANizer (geneorganizer.huji.ac.il), a phenotype-based tool that directly links human genes to the body parts they affect. It is bui...

We study the power of a tournament organizer in manipulating the outcome of a balanced single-elimination tournament by fixing the initial seeding. This problem is known as agenda control for balanced voting trees. It is not known whether there is a polynomial time algorithm that computes a seeding for which a given player can win the tournament, even if the match outcomes for all pairwise play...

Male students perform significantly lower than female students on tests that measure writing achievement. The purpose of this study was to explore the use of a visual graphic organizer application to engage elementary-aged male students who struggle with the writing process. The results suggest that teachers of male students should consider using a visual graphic organizer application for writi...

AIM   To clinically and histopathologically evaluate the anti-inflammatory effect of 0.2% hyaluronan gel alone and with mechanical therapy on gingivitis. The argyrophilic nucleolar organizer region staining technique was attempted to routinely determine its diagnostic and prognostic dependability for periodontal lesions. METHODS   In each of the 28 gingivitis patients, the four quadrants were...

During gastrulation in Xenopus convergence and extension movements, mediated by mediolateral intercalations, are the driving force for early neural plate morphogenesis. Here we show that the winged helix transcriptional regulator, Xfd-12' is dynamically expressed in medial neural plate precursors that undergo convergence and extension movements. These medial neuraxial progenitors are specified ...

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...

Karyotype, C-banding and nucleolar organizer regions (NORs) characteristics of nine Rana ridibunda samples collected from Konya (Meram, Beyşehir, Hadim) province were examined. The diploid number of chromosomes (2n) and the fundamental number of chromosome arms (FN) were determined as 26 and 52, respectively. All of the chromosomes of this species have centromeric constitutive heterochromatin (...

The organizer in vertebrate embryos has been shown to play a central role in their development by antagonizing ventralizing signals and promoting dorsal development. The ventral homeobox gene, Xvex-1, is capable of fulfilling some of the functions of BMP-4. By fusion to activation and repression domains, Xvex-1 was shown to function as a repressor of transcription. The activator version of Xvex...