Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Roxana Gabriela CRISTINA, Ioan I. ARDELEAN
The aim of this study is to determine the time-evolution of live and dead cells as well as the number of colony forming units of E. coli strain DH5α after the passage from LB medium to seawater indoor microcosms. In order to determine the dynamics and survivability capacity with respect to the absence or presence of bacterivores microorganisms E. coli sub-samples were housed in three different microcosms containing filtered (0.22 or 0.45 μm pores) and unfiltered sea water. The microcosms were kept for five days in a sterile environment at a constant temperature of 18 °C in the dark. The samples collected were examined by fluorescent microscopy (SYBER green and Ethidium homodimer) for the determination of cell density (total /dead) and colony forming units quantification (LB and Levine media) in order to establish C.F.U. growth. The results presented in this paper show that the shocks associated with the passage from LB medium to sea water indoor microcosms (hypothermic, hypo-osmotic, including low levels of nutrients, and the presence of bacterivores microorganisms) play a key role in the survival of E. coli cells in this five days period.
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