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...

background and objectives: the development of molecular biological techniques provide a method for direct detection and identification of pathogens. this study attempted to compare bacterial culture and pcr to detect s. agalactiae in cattle milk samples. the pcr method was based on using primers v1 and v2 derived from the 16s rrna gene. materials and methods: one hundred milk samples were colle...

Background: Clarithromycin resistance in Helicbacter pylori has been found to be associated with point mutations in 23s rRNA gene leads to reduced affinity of the antibiotic to its ribosomal target or changing the site of methylation. The aim of this study was to determine the most important point mutations in 23s rRNA gene in H. pylori that are closely related to clarith-romycin resistance amo...