Studies on bacteria-like particles sampled from the stratosphere

Abstract

Bacteria-like particles recovered from the stratosphere and deposited on cellulose acetate membranes have been analysed to confirm their bacterial nature. One particle appeared to be attached to an inorganic 2 particle apparently by mucoid material typically produced by bacteria. A filamentous structure, morphologically similar to a fungal hypha, was also observed. EDS analysis showed that the particles were all non-mineral and therefore could be biological in nature. However, the composition several clumps of nanobacteria-sized particles were found, by SIMS analysis, to be inconsistent with that of bacteria. The results show that it is dangerous to assume that bacteria-like particles seen under scanning electron microscopy are necessarily bacteria.