background: in this study, erythromycin resistance isolates from the students with aged 12-15 yr old were studied and the mutations in the 23s rrna were identified by sequencing. methods: throat samples of 327 students with 12-15 years old from 3 schools of tehran were cultured on the selective strep­tococ­cus pyogenes medium and 23 strains were primarily selected as s. pyogenes . results: all ...

background: to differentiate sarcocystis macro-cyst-forming species in slaughtered sheep in babol area, mazandaran province, sequence analysis of 18s rrna gene was performed. methods: overall, 150 slaughtered sheep were examined macroscopically in slaughterhouse, babol and intra-abdominal and diaphragm muscles tissues infected with macro-cyst of sarcocystis spp. were collected in 2013. one macr...

background : cryptosporidium is an intracellular apicomplexan parasite that infects a wide range of vertebrates including humans. cryptosporidiosis is a major cause of diarrhea in children with and without human immunodeficiency virus (hiv) infection in developing countries. more recently, the molecular methods for identification of morphologically indistin­guishable species have been developed...

The Escherichia coli genome carries seven rRNA (rrn) operons, each containing three rRNA genes. The presence of multiple operons has been an obstacle to many studies of rRNA because the effect of mutations in one operon is diluted by the six remaining wild-type copies. To create a tool useful for manipulating rRNA, we sequentially inactivated from one to all seven of these operons with deletion...

Three small nucleolar RNAs (snoRNAs), E1, E2 and E3, have been described that have unique sequences and interact directly with unique segments of pre-rRNA in vivo. In this report, injection of antisense oligodeoxynucleotides into Xenopus laevis oocytes was used to target the specific degradation of these snoRNAs. Specific disruptions of pre-rRNA processing were then observed, which were reverse...

We characterized a novel 28S rRNA cleavage in cells infected with the murine coronavirus mouse hepatitis virus (MHV). The 28S rRNA cleavage occurred as early as 4 h postinfection (p.i.) in MHV-infected DBT cells, with the appearance of subsequent cleavage products and a decrease in the amount of intact 28S rRNA with increasing times of infection; almost all of the intact 28S rRNA disappeared by...

coastal region of chah bahar port, sea of oman, was screened for the presence of bioluminescence bacteria for the first time. water samples were taken from surface and subsurface layers and immediately spread on nutrient seawater complete (swc) agar. luminous colonies were observed after an overnight incubation at 25°c. among twenty luminous isolates, four of them were selected for preliminary ...

in this research the effects of crude oil on morphological and physiological characterization ofthe cyanobacterium microchaete tenera isc13 were investigated. isolated cyanobacterium treated with different oil concentrations (control, 1, 2.5, 5 and 7%) in carbonless bg110 medium. morphological characteristics such as morphology of filament, cellular shapes and sizes, relative position of hetero...