title: Morphological and immunological characteristics of nanobacteria from human renal stones of a north Indian population.
abstract: The aim of this study was to detect, isolate and characterize the nanobacteria from human renal stones from a north Indian population, and to determine their role in biomineralization. Renal stones retrieved from the kidneys of 65 patients were processed and subjected to mammalian cell culture conditions. The isolated bacteria were examined using scanning (SEM) and transmission electron microscopy (TEM). They were characterized for the presence of DNA, proteins and antigenicity. The role of these bacteria in biomineralization was studied by using the (14)C-oxalate based calcium oxalate monohydrate (COM) crystallization assay. We observed the presence of apatite forming, ultrafilterable gram negative, coccoid microorganisms in 62% of the renal stones. SEM studies revealed 60-200 nm sized organisms with a distinct cell wall and a capsule. TEM images showed needle like apatite structures both within and surrounding them. They were heat sensitive, showed antibiotic resistance and accelerated COM crystallization. A potent signal corresponding to the presence of DNA was observed in demineralized nanobacterial cells by flow cytometry. The protein profile showed the presence of several peptide bands of which those of 18 kDa and 39kDa were prominent. Apatite forming nanosized bacteria are present in human renal stones and may play a role in the pathophysiology of renal stone formation by facilitating crystallization and biomineralization. However, further studies are required to establish the exact mechanism by which nanobacteria are involved in the causation of renal stones.
authors.affiliation: Department of Experiment Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, 160012 Chandigarh, India. madhu_khullar@hotmail.com
authors.forename: Madhu
authors.initials: M
authors.lastname: Khullar
authors.forename: S K
authors.initials: SK
authors.lastname: Sharma
authors.forename: S K
authors.initials: SK
authors.lastname: Singh
authors.forename: Pratibha
authors.initials: P
authors.lastname: Bajwa
authors.forename: Farooq A
authors.initials: FA
authors.lastname: Shiekh
authors.forename: Farooq A
authors.initials: FA
authors.lastname: Sheikh
authors.forename: Vandana
authors.initials: V
authors.lastname: Relan
authors.forename: Meera
authors.initials: M
authors.lastname: Sharma
mesh_terms: D000907:Antibodies, Bacterial; D001031:Apatites / Q000737:chemistry / Q000378:metabolism; D001419:Bacteria / Q000276:immunology* / Q000378:metabolism* / Q000648:ultrastructure; D002129:Calcium Oxalate / Q000737:chemistry / Q000378:metabolism; D002250:Carbon Radioisotopes; D003460:Crystallization; D006801:Humans; D007194:India; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D014545:Urinary Calculi / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial; D001031:Apatites; D002250:Carbon Radioisotopes; D002129:Calcium Oxalate; C030782:carboapatite