objective(s): in recent years, the biosynthesis of gold nanoparticles has been the focus of interest because of their emerging application in a number of areas such as biomedicine. in the present study we report the extracellular biosynthesis of gold nanoparticles (aunps) by using a positive bacterium named streptomyces fulvissimus isolate u from rice fields of guilan province, iran.materials a...

The Clostridium-like organisms TO-931T and HD-17, isolated from human faeces, have high levels of bile acid 7alpha-dehydroxylating activity. Sequencing of their 16S rDNA demonstrated that they belong to cluster XI of the genus Clostridium and that they represent a new and distinct line of descent. Clostridium bifermentans and Clostridium sordellii in cluster XI also possess bile acid 7alpha-deh...

Administration of empirical antibiotic therapy prior to microbiological diagnosis is thought to be associated the failure of subsequent bacterial growth in culture. The aim of this study was to detect bacterial pathogens via direct amplification and sequencing of the 16S rDNA gene in samples showing negative culture results as alternative diagnostic tools to troubleshoot difficult samples. Twen...

The microflora developing during a continuous enrichment culture from a hydrothermal chimney sample was investigated by molecular methods. The culture was performed in a gas-lift bioreactor under anaerobic conditions, at 90°C and pH 6.5, on a complex medium containing sulfur as the terminal electron acceptor. Archaeal and bacterial diversity was studied. Microorganisms affiliated with the gener...

We show for the first time that the ventral diverticulum of the mosquito gut (impermeable sugar storage organ) harbors microorganisms. The gut diverticulum from newly emerged and non-fed Aedes aegypti was dissected under aseptic conditions, homogenized and plated on BHI medium. Microbial isolates were identified by sequencing of 16S rDNA for bacteria and 28S rDNA for yeast. A direct DNA extract...

We have evaluated over a period of 18 months the use of 16S ribosomal DNA (rDNA) sequence analysis as a means of identifying aerobic gram-positive rods in the clinical laboratory. Two collections of strains were studied: (i) 37 clinical strains of gram-positive rods well identified by phenotypic tests, and (ii) 136 clinical isolates difficult to identify by standard microbiological investigatio...

Rapid initiation of antibiotic treatment and fast diagnosis are essential in bacterial infection of the central nervous system (CNS). Culture as common method for detecting bacteria is time consuming and unreliable once antibiotic treatment has been initiated. Eubacterial 16S rDNA-PCR with species differentiation by sequencing appears to be a promising tool. Our experiences with this method per...