Resting forms of Sinorhizobium meliloti

Лойко, Н. Г.; Kryazhevskikh, N. A.; Suzina, N. E.; Demkina, E. V.; Muratova, A. Yu.; Turkovskaya, O. V.; Kozlova, A. N.; Гальченко, В. Ф.; Эль-Регистан, Г. И.

doi:10.1134/s0026261711040126

Cited by 15 publications

(2 citation statements)

References 17 publications

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“…Finding cyst-like cells in S. ureilytica Lr5/4 provides another example in the extending list of resistant cyst-like-producing, non-spore-forming bacteria. This list includes Pseudomonas aeruginosa (Zechman and Casida, 1982), Micrococcus luteus (Mulyukin et al, 1996), Thioalkalivibrio versutus (Loiko et al, 2003), Sinorhizobium meliloti (Loiko et al, 2011), and Arthrobacter globiformis (Demkina et al, 2000), among others (Suzina et al, 2004). Dormancy seems now to be extended to almost every known bacterial phylum, and it has been even suggested that a common “sporulating” ancestor to bacteria might have existed in the past (Tocheva et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2019

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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.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2019

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“…[ 48 , 49 , 50 ]. We have repeatedly observed this broadening of the phase variation potential for cyst-like dormant forms plated on solid media [ 18 , 19 , 47 , 51 ]. The phase variants of the studied HOB species revealed after storage in SHG differed from the dominant variants used for inoculation in their colony morphology and physiological and biochemical characteristics.…”

Section: Discussionmentioning

confidence: 88%

Ways of Long-Term Survival of Hydrocarbon-Oxidizing Bacteria in a New Biocomposite Material—Silanol-Humate Gel

et al. 2023

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Immobilized bacterial cells are presently widely used in the development of bacterial preparations for the bioremediation of contaminated environmental objects. Oil hydrocarbons are among the most abundant pollutants. We have previously described a new biocomposite material containing hydrocarbon-oxidizing bacteria (HOB) embedded in silanol-humate gels (SHG) based on humates and aminopropyltriethoxysilane (APTES); high viable cell titer was maintained in this material for at least 12 months. The goal of the work was to describe the ways of long-term HOB survival in SHG and the relevant morphotypes using the techniques of microbiology, instrumental analytical chemistry and biochemistry, and electron microscopy. Bacteria surviving in SHG were characterized by: (1) capacity for rapid reactivation (growth and hydrocarbon oxidation) in fresh medium; (2) ability to synthesize surface-active compounds, which was not observed in the cultures stored without SHG); (3) elevated stress resistance (ability to grow at high Cu2+ and NaCl concentrations); (4) physiological heterogeneity of the populations, which contained the stationary hypometabolic cells, cystlike anabiotic dormant forms (DF), and ultrasmall cells; (5) occurrence of piles in many cells, which were probably used to exchange genetic material; (6) modification of the phase variants spectrum in the population growing after long-term storage in SHG; and (7) oxidation of ethanol and acetate by HOB populations stored in SHG. The combination of the physiological and cytomorphological properties of the cells surviving in SHG for long periods may indicate a new type of long-term bacterial survival, i.e., in a hypometabolic state.

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