objective :cryptosporidiosis is one of the most important parasitic infections in iran which causes diarrhea in humans and animals. the identification of the cryptosporidium species among humans is necessary. this study aims to identify species of cryptosporidium isolated from patients that referred to three hospitals in tehran based on the 18s rrna gene by nested pcr-rflp assay. ‎methods :in t...

One of the few rRNA modifications conserved between bacteria and eukaryotes is the base dimethylation present at the 3' end of the small subunit rRNA. In the yeast Saccharomyces cerevisiae, this modification is carried out by Dim1p. We previously reported that genetic depletion of Dim1p not only blocked this modification but also strongly inhibited the pre-rRNA processing steps that lead to the...

Significance Ribosomes are complexes between ribosomal RNA (rRNA) and a number of proteins. Because ribosome assembly begins with rRNA folding, we simulated the molecular details Mg 2+ -driven folding central domain bacterial rRNA. Good agreement experiments on three-way junction in center validates model. Coupling binding shows that ions interact segments coordinated manner. The shape changes ...

Eukaryote ribosomal RNAs (rRNAs) have expanded in the course of phylogeny by addition of nucleotides in specific insertion areas, the expansion segments. These number about 40 in the larger (25-28S) rRNA (up to 2,400 nucleotides), and about 12 in the smaller (18S) rRNA (<700 nucleotides). Expansion of the larger rRNA shows a clear phylogenetic increase, with a dramatic rise in mammals and espec...

The copy numbers of 16S rRNA genes in 12 probiotic Lactobacillus strains of poultry origin were analyzed. Genomic DNA of the strains was digested with restriction endonucleases that do not cut within the 16S rRNA gene of the strains. This was followed by Southern hybridization with a biotinylated probe complementary to the 16S rRNA gene. The copy number of the 16S rRNA gene within a Lactobacill...

Current methods used for phylogenetic classification of prokaryotes largely rely on the sequences of 16S rRNA genes that are ubiquitously present in the cell. Theoretical basis of this methodology is based on the assumption that 16S rRNA genes are only vertically inherited and are thus indigenous to each species. However, microbial genomic analysis has revealed the existence of prokaryotic spec...