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Adaptive Strategies in a Poly-Extreme Environment: Differentiation of Vegetative Cells in Serratia ureilytica and Resistance to Extreme Conditions.

ABSTRACT: Poly-extreme terrestrial habitats are often used as analogs to extra-terrestrial environments. Understanding the adaptive strategies allowing bacteria to thrive and survive under these conditions could help in our quest for extra-terrestrial planets suitable for life and understanding how life evolved in the harsh early earth conditions. A prime example of such a survival strategy is the modification of vegetative cells into resistant resting structures. These differentiated cells are often observed in response to harsh environmental conditions. The environmental strain (strain Lr5/4) belonging to Serratia ureilytica was isolated from a geothermal spring in Lirima, Atacama Desert, Chile. The Atacama Desert is the driest habitat on Earth and furthermore, due to its high altitude, it is exposed to an increased amount of UV radiation. The geothermal spring from which the strain was isolated is oligotrophic and the temperature of 54°C exceeds mesophilic conditions (15 to 45°C). Although the vegetative cells were tolerant to various environmental insults (desiccation, extreme pH, glycerol), a modified cell type was formed in response to nutrient deprivation, UV radiation and thermal shock. Scanning (SEM) and Transmission Electron Microscopy (TEM) analyses of vegetative cells and the modified cell structures were performed. In SEM, a change toward a circular shape with reduced size was observed. These circular cells possessed what appears as extra coating layers under TEM. The resistance of the modified cells was also investigated, they were resistant to wet heat, UV radiation and desiccation, while vegetative cells did not withstand any of those conditions. A phylogenomic analysis was undertaken to investigate the presence of known genes involved in dormancy in other bacterial clades. Genes related to spore-formation in Myxococcus and Firmicutes were found in S. ureilytica Lr5/4 genome; however, these genes were not enough for a full sporulation pathway that resembles either group. Although, the molecular pathway of cell differentiation in S. ureilytica Lr5/4 is not fully defined, the identified genes may contribute to the modified phenotype in the Serratia genus. Here, we show that a modified cell structure can occur as a response to extremity in a species that was previously not known to deploy this strategy. This strategy may be widely spread in bacteria, but only expressed under poly-extreme environmental conditions.

SUBMITTER: Filippidou S

PROVIDER: S-EPMC6370625 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Adaptive Strategies in a Poly-Extreme Environment: Differentiation of Vegetative Cells in <i>Serratia ureilytica</i> and Resistance to Extreme Conditions.

Filippidou Sevasti S Junier Thomas T Wunderlin Tina T Kooli Wafa M WM Palmieri Ilona I Al-Dourobi Andrej A Molina Veronica V Lienhard Reto R Spangenberg Jorge E JE Johnson Shannon L SL Chain Patrick S G PSG Dorador Cristina C Junier Pilar P

Frontiers in microbiology 20190205

Poly-extreme terrestrial habitats are often used as analogs to extra-terrestrial environments. Understanding the adaptive strategies allowing bacteria to thrive and survive under these conditions could help in our quest for extra-terrestrial planets suitable for life and understanding how life evolved in the harsh early earth conditions. A prime example of such a survival strategy is the modification of vegetative cells into resistant resting structures. These differentiated cells are often obse ...[more]

PMID: 30804904

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Project description:Background and aimsTrait-based frameworks assess plant survival strategies using different approaches. Some frameworks use functional traits to assign species to a priori defined ecological strategies. Others use functional traits as the central element of a species ecophysiological strategy. We compared these two approaches by asking: (1) what is the primary ecological strategy of three dominant co-occurring shrub species from inselbergs based on the CSR scheme, and (2) what main functional traits characterize the ecophysiological strategy of the species based on their use of carbon, water and light?MethodsWe conducted our study on a Colombian inselberg. In this extreme environment with multiple stressors (high temperatures and low resource availability), we expected all species to be stress tolerant (S in the CSR scheme) and have similar ecophysiological strategies. We measured 22 anatomical, morphological and physiological leaf traits.Key resultsThe three species have convergent ecological strategies as measured by CSR (S, Acanthella sprucei; and S/CS, Mandevilla lancifolia and Tabebuia orinocensis) yet divergent resource-use strategies as measured by their functional traits. A. sprucei has the most conservative carbon use, risky water use and a shade-tolerant strategy. M. lancifolia has acquisitive carbon use, safe water use and a shade-tolerant strategy. T. orinocensis has intermediate carbon use, safe water use and a light-demanding strategy. Additionally, stomatal traits that are easy to measure are valuable to describe resource-use strategies because they are highly correlated with two physiological functions that are hard to measure: stomatal conductance and maximum photosynthesis per unit mass.ConclusionsThe two approaches provide complementary information on species strategies. Plant species can co-occur in extreme environments, such as inselbergs, because they exhibit convergent primary ecological strategies but divergent ecophysiological strategies, allowing them to use limiting resources differently.

Project description:Gene expression profiles of Escherichia coli, grown anaerobically, with or without Acacia mearnsii (Black wattle) extract were compared to identify tannin-resistance strategies. The cell envelope stress protein, spy, and the multidrug transporter-encoding mdtABCD, both under the control of the BaeSR two-component regulatory system, were significantly up-regulated in the presence of tannins. BaeSR mutants were more tannin-sensitive than their wild-type counterparts. Experiment Overall Design: E. coli BW13711 cells were grown anaerobically in continuous culture (d = 0.14h-1) in the presence and absence of Acacia mearnsii (Black Wattle) tannin extract (WTE) at 37Â°C. Under both steady state conditions, E. coli reached an OD600 of ~0.2. The pH at steady-state was 5.7 and 5.3 without and with WTE, respectively. These conditions indicated that the presence of tannins in the medium did not inhibit the growth of E. coli. E. coli BW13711 cells were harvested from continuous culture after steady-state conditions were reached. Duplicate samples were collected after an additional four volume turnover of the culture medium and total RNA was isolated from these samples using the RNeasy mini kit (Qiagen Inc., Valencia, CA). The presence of residual DNA was checked by PCR using the primers for amplification of cca. If necessary, the remaining DNA was removed by RQ1 RNase-Free DNase (Promega corp, Madison, WI) according to the manufacturerâs instructions. E. coli whole genome transcriptional profiling was performed by hybridization on the GeneChipÂ® E. coli Antisense Genome Array (Affymetrix Inc., Santa Clara, CA) according to the manufacturerâs instructions. Microarray data were analyzed using MicroArray Suite 5.0 (Affymetrix Inc.) and GeneSpring 5.0 (Silicon Genetics, Redwood City, CA) software. The 95% confidence interval of the WTE array duplicates demonstrated that genes >1.9 times up- or down-regulated could be considered as significantly differentially regulated. After removing significantly up- or down-regulated genes which had large variability in expression on the duplicate arrays, it was found that in total 1,498 genes were up- or down-regulated

Dataset Information

Adaptive Strategies in a Poly-Extreme Environment: Differentiation of Vegetative Cells in Serratia ureilytica and Resistance to Extreme Conditions.

Publications

Adaptive Strategies in a Poly-Extreme Environment: Differentiation of Vegetative Cells in <i>Serratia ureilytica</i> and Resistance to Extreme Conditions.

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