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    Studies on bacteria-like particles sampled from the stratosphere
    (Springer, 2004-07-28) Wainwright, M.; Weber, P. K.; Smith, J. B.; et al.
    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.
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    Microorganisms cultured from stratospheric air samples obtained at 41 km
    (Elsevier Science Publishers, 2002-12-03) Wainwright, M.; Wickramasinghe, N. C.; Narlikar, J. V.; et al.
    Samples of air removed from the stratosphere, at an altitude of 41 km, were previously found to contain viable, but non-cultureable bacteria (cocci and rods). Here, we describe experiments aimed at growing these, together with any other organisms, present in these samples. Two bacteria (Bacillus simplex and Staphylococcus pasteuri) and a single fungus, Engyodontium album (Limber) de Hoog were isolated from the samples. Although the possibility of contamination can never be ruled out when space-derived samples are studied on earth, we are confident that the organisms originated from the stratosphere. Possible mechanisms by which these organisms could have attained such a height are discussed
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    Detection of living cells in stratospheric samples
    (SPIE Conference, 2002-04-14) Narlikar, J. V.; Harris, Melanie J.; Wickramasinghe, N. C.; et al.
    Air samples collected aseptically over tropical India at various stratospheric altitudes ranging from 20 to 41 km using cryosampler assemblies carried on balloons flown from Hyderabad have shown evidence of living microbial cells. Unambiguous evidence of living cells came from examining micropore filters on which the samples were recovered with the use of voltage sensitive lipophilic dyes that could detect the presence of active cells. Clumps of viable cells were found at all altitudes using this technique, and this conclusion was found to be consistent with images obtained from electron microscopy. Since the 41 km sample was collected well above the local tropopause, aprimafacie case for a space incidence of these microoraganisms is established. Further work on culturing, PCR analysis and isotopic analysis is in progress.
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    Search for living cells in stratospheric samples
    (SPIE, 1998-07-14) Narlikar, J. V.; Ramadurai, S.; Bhargava, Pushpa; et al.
    Air samples are to be collected at various altitudes in the stratosphere using balloons flown from Hyderabad, India. The samples will be passed through sterile micropore filters, after which the filters will be analysed using voltage sensitive lipophilic dyes to detect the presence of either active or non-active cells. Organisms detected in this manner will be studied using static mass spectroscopy to establish isotopic ratios (superscript 13)C/(superscript 12)C and D/H, which would distinguish between terrestrial and extraterrestrial cells.