title: Selective recovery of Streptosporangium fragile from soil by indirect immunomagnetic capture.
abstract: A polyclonal antibody raised to Streptosporangium fragile spores reacted strongly and specifically with the immunizing strain and to a number of related species of Streptosporangium, as determined by dot immunoblotting. An indirect immunomagnetic capture method was developed for the recovery of the target organism from sterile and non-sterile soil, using sheep anti-rabbit M-280 Dynabeads. The effects of different soil blocking agents, antibody labelling concentrations and spore/Dynabead capture times on the recovery of S. fragile spores were investigated. Pre-blocking of antibody binding sites within the soil, with either 2% partially hydrolysed gelatin or 10% skimmed milk, was essential prior to immunomagnetic capture. Increasing the capture time from 15 to 60 min did not affect spore recovery; however, a 10-fold decline in the magnetic bead concentration did result in a significantly lower recovery of spores from soil. S. fragile was selectively enriched (1:190-fold) when present as a mixed population with Arthrobacter oxydans in sterile soil. The indirect immunomagnetic capture method was used to selectively recover S. fragile spores seeded into non-sterile soil, although some background binding of non-target bacteria was noted. The target was successfully recovered from a sterile soil microcosm after 14 d incubation and the capture rate was increased by the inclusion of an initial soil dispersion and biomass concentration procedure, using the ion-exchange resin Chelex 100.
mesh_terms: D000192:Actinomycetales / Q000276:immunology / Q000302:isolation & purification*; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D001173:Arthrobacter / Q000302:isolation & purification; D001431:Bacteriological Techniques; D002411:Cation Exchange Resins; D002614:Chelating Agents; D018189:Immunomagnetic Separation; D008863:Microspheres; D011817:Rabbits; D012117:Resins, Synthetic; D012988:Soil Microbiology; D013171:Spores, Bacterial
chemical_list: D000907:Antibodies, Bacterial; D002411:Cation Exchange Resins; D002614:Chelating Agents; D012117:Resins, Synthetic; C024997:Chelex 100