Flow Cytometric Investigation of Salinicola halophilus S28 Physiological Response Provides Solid Evidence for Its Uncommon and High Ability to Face Salt-Stress Conditions
Metadata
Show full item recordMateria
Salinicola halophilus Flow cytometry Cell physiological status Salinity stress Saline di Tarquinia
Date
2023-04-01Referencia bibliográfica
Juárez-Jiménez, B.; Fenice, M.; Pasqualetti, M.; Muñoz-Palazon, B.; Correa-Galeote, D.; Braconcini, M.; Gorrasi, S. Flow Cytometric Investigation of Salinicola halophilus S28 Physiological Response Provides Solid Evidence for Its Uncommon and High Ability to Face Salt-Stress Conditions. Microbiol. Res. 2023, 14, 454–465. [https://doi.org/10.3390/ microbiolres14020034]
Abstract
In a previous work, some bacterial strains isolated from the Saline di Tarquinia marine
salterns (Viterbo, Italy) showed very unusual growth profiles in relation to temperature and salinity
variations when grown in solid media. In particular, Salinicola halophilus S28 showed optimal or
suboptimal growth in a very wide range of NaCl concentrations, suggesting a great coping ability
with salinity variations. These intriguing outcomes did not fit with the general Salinicola halophilus
description as a moderately halophilic species. Therefore, this study profiles the actual physiological
status of S28 cells subjected to different NaCl concentrations to provide evidence for the actual
coping ability of strain S28 with broad salinity variations. Flow cytometry was selected as the
evaluation method to study the physiological status of bacterial cells subjected to different salinity
levels, monitoring the strain response at different growth phases over 72 h. Strain S28 showed
maximal growth at 8% NaCl; however, it grew very well with no statistically significant differences at
all salinity conditions (4–24% NaCl). Flow cytometric results provided clear evidence of its actual and
strong ability to face increasing salinity, revealing a good physiological response up to 24% of NaCl. In
addition, strain S28 showed very similar cell physiological status at all salinity levels, as also indicated
by the flat growth profile revealed in the range of 4–24% NaCl. This is the first study regarding
the physiological response during the growth of halophilic bacteria under different conditions of
salinity via flow cytometry. This technique represents an effective tool for the investigation of the
physiological status of each cell, even if it is somehow underrated and underused by microbiologists
for this purpose.