Strategy for the Adaptation to Stressful Conditions of the Novel Isolated Conditional Piezophilic Strain Halomonas titanicae ANRCS81

Abstract

Microbial growth and metabolic responses to environmental changes are core aspects of adaptation strategies developed during evolution. In particular, high hydrostatic pressure (HHP) is the most common but least examined environmental factor driving microbial adaptation in the deep sea.

High hydrostatic pressure stimulates microbial nitrate reduction in hadal trench sediments under oxic conditions

“…This is consistent with previous studies that energy metabolism and high-pressure adaptation were coordinated in marine denitrifiers and nitrate reducers. For example, the transcriptional level of genes involved in energy metabolic pathways, such as glycolysis, dissimilatory nitrate reduction, denitrification, and TCA cycle was stimulated by high hydrostatic pressure in Halomonas titanicae ANRCS81 22 . Marine nitrate reducers, Caminibacter mediatlanticus and Thermovibrio ammonificans with higher-energies yielding capacity, were better adapted to high hydrostatic pressures 23 .…”

“…Besides, high hydrostatic pressures induce intracellular oxidative stress (Supplementary Fig. 5 ), which impairs physiological functions 17 , 22 , 26 , 27 . Under oxidative stress, cells prefer to use nitrate rather than oxygen as the terminal electron acceptor to prevent further reactive oxygen species (ROS) accumulation 22 .…”

“…5 ), which impairs physiological functions 17 , 22 , 26 , 27 . Under oxidative stress, cells prefer to use nitrate rather than oxygen as the terminal electron acceptor to prevent further reactive oxygen species (ROS) accumulation 22 . Thus, energy preservation for cellular maintenance and the avoidance of oxidative stress under high hydrostatic pressures could be one of the mechanisms behind the enhancement of denitrification over aerobic respiration even under oxic conditions.…”

“…After the incubation, total RNA was extracted with the common TRIzol method 27 , and RNA samples in triplicate were subjected to quality control and sequencing on the Illumina platform at Shanghai Personal Biotechnology (Shanghai, China). The subsequent transcriptomic analysis was performed as described previously 22 .…”

The TorRS two component system regulates expression of TMAO reductase in response to high hydrostatic pressure in Vibrio fluvialis

“…Increasing evidence showed that several extreme environmental conditions, e.g., pressure, temperature, salinity, and pH, had similar effect on microbial cells and will interfere with the redox homeostasis. Accordingly, a common adaptation mechanism is adopted to cope with different types of stresses (Zhang et al, 2015;Wang et al, 2021;Li et al, 2023). Studies in E. coli showed that TorRS system also regulates genes involved in alkaline-resistance, such as tnaA, gadA and hdeABD, facilitating the cells to deal with the increase of pH resulted from TMAO reduction (Bordi et al, 2003).…”