Research Papers (JVN)

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Confirmation of the presence of viable but non-culturable bacteria in the stratosphere
(Cambridge University Press, 2004-01-05) Wainwright, M.; Wickramasinghe, N. C.; Narlikar, J. V.; et al.
The presence of viable, but non-cultureable, bacteria on membranes through which stratospheric air samples were passed has been confirmed using viable fluorescent staining.
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.