Growth of Lactobacillus reuteri DSM17938 Under Two Simulated Microgravity Systems: Changes in Reuterin Production, Gastrointestinal Passage Resistance, and Stress Genes Expression Response
There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
<p class="first" id="d4931456e83">Extreme factors such as space microgravity, radiation,
and magnetic field differ from
those that occur on Earth. Microgravity may induce and select some microorganisms
for physiological, metabolic, and/or genetic variations. This study was conducted
to determine the effects of simulated microgravity conditions on the metabolism and
gene expression of the probiotic bacterium Lactobacillus reuteri DSM17938. To investigate
microbial response to simulated microgravity, two devices-the rotating wall vessel
(RWV) and the random positioning machine (RPM)-were used. Microbial growth, reuterin
production, and resistance to gastrointestinal passage were assessed, and morphological
characteristics were analyzed by scanning electron microscopy. The expression of some
selected genes that are responsive to stress conditions and to bile salts stress was
evaluated through real-time quantitative polymerase chain reaction assay. Monitoring
of bacterial growth, cell size, and shape under simulated microgravity did not reveal
differences compared with 1 × g controls. On the contrary, an enhanced production
of reuterin and a greater tolerance to the gastrointestinal passage were observed.
Moreover, some stress genes were upregulated under RWV conditions, especially after
24 h of treatment, whereas RPM conditions seemed to determine a downregulation over
time of the same stress genes. These results show that simulated microgravity could
alter some physiological characteristics of L. reuteri DSM17938 with regard to tolerance
toward stress conditions encountered on space missions and could be useful to elucidate
the adaptation mechanisms of microbes to the space environment.
</p>