Search results for "nucleolus"

High levels of the molecular chaperone Mdg1/ERdj4 reflect the activation state of endothelial cells

2003

Mdg1/ERdj4, a mammalian chaperone that belongs to the HSP40 protein family, has been reported to be located in the endoplasmic reticulum (ER), is induced by ER stress, and protects ER stressed cells from apoptosis. Here we show that under normal physiological conditions, Mdg1/ERdj4 is expressed at various levels in the vasculature due to different activation states of the endothelium. To elucidate the stimuli that induce ER stress and thus upregulate Mdg1/ERdj4, we investigated the effect of several endothelium specific stressors on its expression. Mdg1/ERdj4 mRNA is induced by activated macrophages, by nitric oxide (NO) and heat shock, and during terminal cell differentiation, whereas shea…

Kinetics of expression of prion protein in uninfected and scrapie-infected N2a mouse neuroblastoma cells.

1993

The scrapie prion protein, PrPSc, is formed from its isoform, the cellular PrPc. There is evidence available indicating that PrPSc is necessary component of the infectious prion particle to cause a series of transmissible spongiform encephalopathies. We have used immunocytochemistry and RNA blotting techniques to investigate if infection with prions results in an increased PrP gene expression. For the experiments we used N2a cells which had been infected with prions (ScN2a cells). We demonstrated by confocal laser scanning microscopy that PrP-protein was present in the nucleus (predominantly in the nucleoli) of ScN2a cells. Analysis of the PrP-mRNA levels both in N2a- and in ScN2a cells usi…

Conventional karyotype, nucleolar organizer regions and genome size in five Mediterranean species of Syngnathidae (Pisces, Syngnathiformes)

1998

Conventional karyotypes, NOR-bearing chromosomes by means of silver impregnation and genome size were investigated in five Mediterranean species in three genera of the Syngnathidae. A karyotype of 48 subtelocentric-acrocentric chromosomes was found in the seahorse Hippocampus hippocampus (FN=48) while a diploid value of 44 occurred in H. guttulatus (2 sm-m+42 a; FN=46) and the pipefish Syngnathus abaster (44 a; FN=44) and S. typhle (44 a; FN=44). The pipefish Nerophis ophidion, possessing a diploid chromosomal set of 58 made up of 50 meta-submetacentric and eight subteloacrocentric elements (FN=108) and a genome size three to four times larger than those known to date, differs cytogenetical…

Karyotype analyses reveal inter-individual polymorphism and association of nucleolus-organizer-carrying chromosomes in Capros aper (Pisces: Zeiformes)

1992

Three different karyomorphs with 2n=46, 2n=44 and 2n=42 for Capros aper (L., 1758) (Zeiformes) collected from the Gulf of Lion, near Banyuls-sur-Mer, France, in July 1990 were determined. Karyomorphs were characterized by the same arm number [Fundamental number (FN)=50], suggesting that chromosome variations are due to Robertsonian fusions. In somatic metaphase spreads stained with silver nitrate, nucleolus organizer regions (NORs) consistently occupied a terminal position on the short arms of two small submetacentric chromosomes. Ca. 30% of silver-stained metaphases in each specimen showed NOR chromosomes associated in pairs by their nucleolus organizer regions.

Karyotype analysis, nucleolus organizer regions and C-banding pattern of Eisenia foetida (oligochaeta, lumbricidae)

1991

The diploid number 2n=22 and haploid number n=11 found for Eisenia foetida from Palermo, Italy, confirm earlier data for this species from other localities. Analyses of silver-stained and C-banded mitotic and meiotic chromosomes suggest that a single chromosome pair has active NORs which correspond with C-positive regions. The occurrence of nucleolus activity during spermatogenesis of E. foetida is ascertained.

Karyological and Molecular Characterization of Mullus surmuletus and Mullus barbatus(Pisces, Mullidae).

1992

The modal diploid number of 44 chromosomes has been found in Mullus surmuletus and Mullus barbatus (Pisces, Mullidae). Two middle-sized subtelocentric chromosomes are involved in nucleolus organization (NORs) in both Mullus species. Despite similarity in the NOR location, valuable differences in the restriction pattern of the ribosomal genes have been observed.

2013

Abstract Background The cumulus cells (CCs) enveloping antral and ovulated oocytes have been regarded as putative source of non-invasive markers of the oocyte developmental competence. A number of studies have indeed observed a correlation between CCs gene expression, embryo quality, and final pregnancy outcome. Here, we isolated CCs from antral mouse oocytes of known developmental incompetence (NSN-CCs) or competence (SN-CCs) and compared their transcriptomes with the aim of identifying distinct marker transcripts. Results Global gene expression analysis highlighted that both types of CCs share similar transcriptomes, with the exception of 422 genes, 97.6% of which were down-regulated in N…

Characterization of mitotic and meiotic, chromosomes of the vermetid gastropodDendropoma (Novastoa) Petraeum(Monterosato, 1884) (Mollusca, Caenogastr…

1997

Abstract The vermetid gastropod Dendropoma (Novastoa) petraeum from the Northwestern coast of Sicily was investigated karyologically. The count of spermatocyte bivalents at diakinesis gave the haploid number of this species as n=17. The count of mitotic chromosomes in males, females and early developing embryos gave the diploid number as 2n=34. Irrespective of sex, the karyotype of D. petraeum consists of 17 homomorphic chromosome pairs, of which 8 are metacentric, 4 subtelocentric and 5 acrocentric. This species is characterized by the presence of two chromosomes per cell involved in nucleolus organization (NOR) and by a low amount of constitutive heterochromatin.

Spermatocyte chromosome analysis of the slugLehmannia melitensis(Lessona and Pollonera, 1891) (Mollusca, Pulmonata) using conventional, NOR- and C-ba…

1993

SUMMARYDiploid number 2n = 40 and haploid number n = 20 for the slug Lehmannia melitensis have been determined. These chromosome values being considerably different from those reported for slugs belonging to other limacid genera support the notion that the genus Lehmannia is particular within the family Limacidae. Nucleolus organizer regions (NORs) and C-banding pattern of L. melitensis are described.

Cytogenetic characterization ofBrachidontes pharaonis(Fisher P., 1870): Karyotype, banding and fluorescentin situhybridization (fish) (Mollusca: Biva…

2000

Abstract The mussel Brachidontes pharaonis (Fisher P., 1870) (Bivalvia: Mytilidae) has a diploid chromosomal set of 28 made up of 14 pairs of which eight are mono-armed (ST) and six bi-armed (M+SM). Fourteen bivalents occur in spermatocytes both at pachytene and metaphase-I. The use of combined silver and CMA3 staining reveals that nucleolus organizer regions (NORs) are located terminally on the long arm of a small subtelocentric chromosome pair (pair 14) and are compartmentalized in GC base pairs. A Paracentrotus lividus (Echinodermata) 4.3 kilobase (kb) rDNA probe (prR14) consisting of sequences from the 3′ end of 18S rDNA to the 3′ end of 26S rDNA was used to map the rDNA loci of B. phar…