RESUMO
UNLABELLED: Identity of causative agent of rhinosporidiosis (Rhinosporidium seeberi) has been controversial since the disease was described in 1900. Extensive sequence alignments and phylogenetic analyses of 16S rRNA gene detected recently by us in R. seeberi , revealed 99% similarity with 16S rDNA in chloroplasts of flowering plants. Study demonstrates R. seeberi is a pigmented prokaryote displaying some characteristics of cyanobacteria, and contains 16S rDNA present in chloroplasts of all groups of land plants. This study and our recent publication of 2006 are the first molecular studies using purified organismal DNA extracted from R. seeberi free of infected tissue. ABBREVIATIONS: RB - Round body.
RESUMO
Polyps of rhinosporidiosis contain microscopic round bodies, believed to be causative agents of the disease. The source and identity of these round bodies has been debated ever since the first case was described in the year 1900. Most patients have a history of exposure to pond water. Collection and microscopic analysis of pond water samples where patients had been dipping led to the idea that a cyanobacterium could possibly develop into round bodies after entering the patient's nose. Molecular genomic studies based on PCR, cloning, and sequencing were, therefore, carried out using purified DNA, extracted from individually separated round bodies from polyp samples. Parallel investigations were also conducted on DNA extracted from cyanobacterium Microcystis isolated from pond water samples. The results of these experiments presented here provide evidence of the presence of 1458 bp 16S rRNA gene in round bodies. This is the first molecular study indicating the prokaryotic identity of round bodies in rhinosporidiosis.
