Osmotic response in Leptospirillum ferriphilum isolated from an industrial copper bioleaching environment to sulfate.

Iron and sulfur-oxidizing microorganisms play important roles in several natural and industrial processes. Leptospirillum (L.) ferriphilum, is an iron-oxidizing microorganism with a remarkable adaptability to thrive in extreme acidic environments, including heap bioleaching processes, acid mine drainage (AMD) and natural acidic water. A strain of L. ferriphilum (IESL25) was isolated from an industrial bioleaching process in northern Chile. This strain was challenged to grow at increasing concentrations of sulfate in order to assess changes in protein expression profiles, cells shape and to determine potential compatible solute molecules. The results unveiled changes in three proteins: succinyl CoA (SCoA) synthetase, isocitrate dehydrogenase (IDH) and aspartate semialdehyde dehydrogenase (ASD); which were notably overexpressed when the strain grew at elevated concentrations of sulfate. ASD plays a pivotal role in the synthesis of the compatible solute ectoine, which was identified along with hydroxyectoine by using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF). The relationship between IDH, SCoA, and ectoine production could be due to the TCA cycle, in which both enzymes produce metabolites that can be utilized as precursors or intermediates in the biosynthesis of ectoine. In addition, distinct filamentous cellular morphology in L. ferriphilum IESL25 was observed when growing under sulfate stress conditions. This study highlights a new insight into the possible cellular responses of L. ferriphilum under the presence of high sulfate levels, commonly found in bioleaching of sulfide minerals or AMD environments.

Complete genome sequence of a haloalkaliphilic heterotrophic bacterium Halomonas salifodinae IM328.

The genome of a halophilic bacterium Halomonas salifodinae IM328 was completely sequenced in order to offer convenience for the research such as the synthesis of compatible solutes. The genome contains a circular chromosome which was sequenced by PacBio system.

Stochastic Character Mapping, Bayesian Model Selection, and Biosynthetic Pathways Shed New Light on the Evolution of Habitat Preference in Cyanobacteria.

Cyanobacteria are the only prokaryotes to have evolved oxygenic photosynthesis paving the way for complex life. Studying the evolution and ecological niche of cyanobacteria and their ancestors is crucial for understanding the intricate dynamics of biosphere evolution. These organisms frequently deal with environmental stressors such as salinity and drought, and they employ compatible solutes as a mechanism to cope with these challenges. Compatible solutes are small molecules that help maintain cellular osmotic balance in high salinity environments, such as marine waters. Their production plays a crucial role in salt tolerance, which, in turn, influences habitat preference. Among the five known compatible solutes produced by cyanobacteria (sucrose, trehalose, glucosylglycerol, glucosylglycerate, and glycine betaine), their synthesis varies between individual strains. In this study, we work in a Bayesian stochastic mapping framework, integrating multiple sources of information about compatible solute biosynthesis in order to predict the ancestral habitat preference of Cyanobacteria. Through extensive model selection analyses and statistical tests for correlation, we identify glucosylglycerol and glucosylglycerate as the most significantly correlated with habitat preference, while trehalose exhibits the weakest correlation. Additionally, glucosylglycerol, glucosylglycerate, and glycine betaine show high loss/gain rate ratios, indicating their potential role in adaptability, while sucrose and trehalose are less likely to be lost due to their additional cellular functions. Contrary to previous findings, our analyses predict that the last common ancestor of Cyanobacteria (living at around 3180 Ma) had a 97% probability of a high salinity habitat preference and was likely able to synthesise glucosylglycerol and glucosylglycerate. Nevertheless, cyanobacteria likely colonized low-salinity environments shortly after their origin, with an 89% probability of the first cyanobacterium with low-salinity habitat preference arising prior to the Great Oxygenation Event (2460 Ma). Stochastic mapping analyses provide evidence of cyanobacteria inhabiting early marine habitats, aiding in the interpretation of the geological record. Our age estimate of ~2590 Ma for the divergence of two major cyanobacterial clades (Macro- and Microcyanobacteria) suggests that these were likely significant contributors to primary productivity in marine habitats in the lead-up to the Great Oxygenation Event, and thus played a pivotal role in triggering the sudden increase in atmospheric oxygen.

Osmotic stress response of the coral and oyster pathogen Vibrio coralliilyticus: acquisition of catabolism gene clusters for the compatible solute and signaling molecule myo-inositol.

Marine bacteria experience fluctuations in osmolarity that they must adapt to, and most bacteria respond to high osmolarity by accumulating compatible solutes also known as osmolytes. The osmotic stress response and compatible solutes used by the coral and oyster pathogen Vibrio coralliilyticus were unknown. In this study, we showed that to alleviate osmotic stress V. coralliilyticus biosynthesized glycine betaine (GB) and transported into the cell choline, GB, ectoine, dimethylglycine, and dimethylsulfoniopropionate, but not myo-inositol. Myo-inositol is a stress protectant and a signaling molecule that is biosynthesized and used by algae. Bioinformatics identified myo-inositol (iol) catabolism clusters in V. coralliilyticus and other Vibrio, Photobacterium, Grimontia, and Enterovibrio species. Growth pattern analysis demonstrated that V. coralliilyticus utilized myo-inositol as a sole carbon source, with a short lag time of 3 h. An iolG deletion mutant, which encodes an inositol dehydrogenase, was unable to grow on myo-inositol. Within the iol clusters were an MFS-type (iolT1) and an ABC-type (iolXYZ) transporter and analyses showed that both transported myo-inositol. IolG and IolA phylogeny among Vibrionaceae species showed different evolutionary histories indicating multiple acquisition events. Outside of Vibrionaceae, IolG was most closely related to IolG from a small group of Aeromonas fish and human pathogens and Providencia species. However, IolG from hypervirulent A. hydrophila strains clustered with IolG from Enterobacter, and divergently from Pectobacterium, Brenneria, and Dickeya plant pathogens. The iol cluster was also present within Aliiroseovarius, Burkholderia, Endozoicomonas, Halomonas, Labrenzia, Marinomonas, Marinobacterium, Cobetia, Pantoea, and Pseudomonas, of which many species were associated with marine flora and fauna.IMPORTANCEHost associated bacteria such as Vibrio coralliilyticus encounter competition for nutrients and have evolved metabolic strategies to better compete for food. Emerging studies show that myo-inositol is exchanged in the coral-algae symbiosis, is likely involved in signaling, but is also an osmolyte in algae. The bacterial consumption of myo-inositol could contribute to a breakdown of the coral-algae symbiosis during thermal stress or disrupt the coral microbiome. Phylogenetic analyses showed that the evolutionary history of myo-inositol metabolism is complex, acquired multiple times in Vibrio, but acquired once in many bacterial plant pathogens. Further analysis also showed that a conserved iol cluster is prevalent among many marine species (commensals, mutualists, and pathogens) associated with marine flora and fauna, algae, sponges, corals, molluscs, crustaceans, and fish.

Physiological response of Metarhizium rileyi with linoleic acid supplementation.

Metarhizium rileyi has a broad biocontrol spectrum but is highly sensitive to abiotic factors. A Colombian isolate M. rileyi Nm017 has shown notorious potential against Helicoverpa zea. However, it has a loss of up to 22 % of its conidial germination after drying, which limits its potential as a biocontrol agent and further commercialization. Conidial desiccation resistance can be enhanced by nutritional supplements, which promotes field adaptability and facilitates technological development as a biopesticide. In this study, the effect of culture medium supplemented with linoleic acid on desiccation tolerance in Nm017 conidia was evaluated. Results showed that using a 2 % linoleic acid-supplemented medium increased the relative germination after drying by 41 % compared to the control treatment, without affecting insecticidal activity on H. zea. Also, the fungus increased the synthesis of trehalose, glucose, and erythritol during drying, independently of linoleic acid use. Ultrastructural analyses of the cell wall-membrane showed a loss of thickness by 22 % and 25 %, in samples obtained from 2 % linoleic acid supplementation and the control, respectively. Regarding its morphological characteristics, conidia inner area from both treatments did not change after drying. However, conidia from the control had a 24 % decrease in length/width ratio, whereas there was no alteration in conidia from acid linoleic. The average value of dry conidia elasticity coefficient from linoleic acid treatment was 200 % above the control. Medium supplementation with linoleic acid is a promising fermentation strategy for obtaining more tolerant conidia without affecting production and biocontrol parameters, compatible solutes synthesis, or modifying its cell configuration.

Gelation behavior and mechanism of low methoxyl pectin in the presence of erythritol and sucrose: The role of co-solutes.

Co-solutes such as sucrose and sugar alcohol play a significant part in low methoxyl pectin (LMP) gelation. To explore their gelation mechanism, we investigated the gelation behavior of LMP in the presence of erythritol and sucrose with Ca2+. Results revealed that the introduction of erythritol and sucrose improved the hardness of the gels, fixed more free water, accelerated the rate of gel structuring, and enhanced the gel strength. FT-IR confirmed the reinforced hydrogen bonding and hydrophobic forces between the pectin chains after introducing co-solutes. And it could be observed clearly by SEM that the cross-linking density of gel network enhanced with co-solutes. Furthermore, gel disruption experiments suggested the presence of ionic interaction, hydrogen bonding, and hydrophobic forces in LMP gels. Finally, we concluded that the egg-box regions cross-linked only by LMP and Ca2+ were too weak to form a stable gel network structure. Adding co-solutes could increase the amount of cross-linking between pectin chains and enlarge the cross-linking zones, which favored the formation of a dense gel network by more hydrogen bonding and hydrophobic forces. Sucrose gels had superior physicochemical properties and microstructure than erythritol gels due to sucrose's excellent hydration capacity and chemical structure characteristics.

Salinity Tolerance and Osmoadaptation Strategies in Four Genera of Anammox Bacteria: Brocadia, Jettenia, Kuenenia, and Scalindua.

The salinity tolerance and osmoadaptation strategies in four phylogenetically distant anammox species, Brocadia, Jettenia, Kuenenia, and Scalindua, were investigated by using highly enriched cell cultures. The first-emerged "Ca. Scalindua sp." showed optimum growth at 1.5-3% salinity and was tolerant to ∼10% salinity (a slight halophile). The second-emerged "Ca. Kuenenia stuttgartiensis" was tolerant to ∼6% salinity with optimum growth at 0.25-1.5% (a halotolerant). These early-emerged "Ca. Scalindua sp." and ″Ca. K. stuttgartiensis" rapidly accumulated K+ ions and simultaneously synthesized glutamate as a counterion. Subsequently, part of the glutamate was replaced by trehalose. In contrast, the late-emerged "Ca. B. sinica" and "Ca. J. caeni" were unable to accumulate sufficient amounts of K+─glutamate and trehalose, resulting in a significant decrease in activity even at 1-2% salinity (nonhalophiles). In addition, the external addition of glutamate may increase anammox activity at high salinity. The species-dependent salinity tolerance and osmoadaptation strategies were consistent with the genetic potential required for the biosynthesis and transport of these osmolytes and the evolutionary history of anammox bacteria: Scalindua first emerged in marine environments and then Kuenenia and other two species gradually expanded their habitat to estuaries, freshwater, and terrestrial environments, while Brocadia and Jettenia likely lost their ability to accumulate K+─glutamate.

Effect of Mechanical Vibration on Kinetics of Solute Adsorption.

INTRODUCTION: Hemadsorption with new sorbent cartridges is an emerging extracorporeal blood purification technique. Flow distribution inside the sorbent is one of the main issues concerning the device's performance and optimal sorbent utilization. In this experiment, we aimed to investigate the efficacy of vibration during adsorption by measuring the removal of vancomycin. METHODS: In this experimental study, 1,000 mL of saline with 10 g of vancomycin was circulated in a closed circuit (set flow of 250 mL/min) simulating a hemadsorption blood run using HA380 minimodule cartridge containing 75 g of wet resin. This vibration model was implemented with a damping head device installed in front of the adsorption cartridge during the experiment. The kinetics of the vancomycin were assessed by removal ratio over 120 min. RESULTS: We found no difference between the two models. Adsorption with and without vibration did not differ significantly for partial reduction ratios, overall amount of adsorbed molecule, or adsorption kinetics. CONCLUSION: The current design and structure of the minimodule cartridge demonstrated no difference in small-middle solute removal. Further improvement with the addition of mechanical vibration to the device was not observed.

In vitro Removal of Protein-Bound Retention Solutes by Extracorporeal Blood Purification Procedures.

INTRODUCTION: When the kidneys or liver fail, toxic metabolites accumulate in the patient's blood, causing cardiovascular and neurotoxic complications and increased mortality. Conventional membrane-based extracorporeal blood purification procedures cannot remove these toxins efficiently. The aim of this in vitro study was to determine whether commercial hemoperfusion adsorbers are suitable for removing protein-bound retention solutes from human plasma and whole blood as well as to compare the removal to conventional hemodialysis. METHODS: For in vitro testing of the removal of protein-bound substances, whole blood and plasma were spiked with uremic retention solutes (homocysteine, hippuric acid, indoxyl sulfate, 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid) and the toxins of liver failure (bilirubin, cholic acid, tryptophan, phenol). Subsequently, the protein binding of each retention solute was determined. The adsorption characteristics of the hemoperfusion adsorbers, Jafron HA and Biosky MG, both approved for the adsorption of protein-bound uremic retention solutes and Cytosorb, an adsorber recommended for adsorption of cytokines, were tested by incubating them in spiked whole blood or plasma for 1 h. Subsequently, the adsorption characteristics of the adsorbers were tested in a dynamic system. For this purpose, a 6-h in vitro hemoperfusion treatment was compared with an equally long in vitro hemodialysis treatment. RESULTS: Hippuric acid, homocysteine, indoxyl sulfate, and tryptophan were most effectively removed by hemodialysis. Bilirubin and cholic acid were removed best by hemoperfusion with Cytosorb. A treatment with Jafron HA and Biosky MG showed similar results for the adsorption of the tested retention solutes and were best for removing phenol. 3-Carboxy-4-methyl-5-propyl-2-furanpropionic acid could not be removed with any treatment method. DISCUSSION/CONCLUSION: A combination of hemodialysis with hemoperfusion seems promising to improve the removal of some toxic metabolites in extracorporeal therapies. However, some very strongly protein-bound metabolites cannot be removed adequately with the adsorbers tested.

Enhancing salinity tolerance in cucumber through Selenium biofortification and grafting.

BACKGROUND: Salinity stress is a major limiting factor for plant growth, particularly in arid and semi-arid environments. To mitigate the detrimental effects of salinity stress on vegetable production, selenium (Se) biofortification and grafting onto tolerant rootstocks have emerged as effective and sustainable cultivation practices. This study aimed to investigate the combined effects of Se biofortification and grafting onto tolerant rootstock on the yield of cucumber grown under salinity stress greenhouse conditions. The experiment followed a completely randomized factorial design with three factors: salinity level (0, 50, and 100 mM of NaCl), foliar Se application (0, 5, and 10 mg L-1 of sodium selenate) and grafting (grafted and non-grafted plants) using pumpkin (Cucurbita maxima) as the rootstock. Each treatment was triplicated. RESULTS: The results of this study showed that Se biofortification and grafting significantly enhanced salinity tolerance in grafted cucumbers, leading to increased yield and growth. Moreover, under salinity stress conditions, Se-Biofortified plants exhibited increased leaf relative water content (RWC), proline, total soluble sugars, protein, phenol, flavonoids, and antioxidant enzymes. These findings indicate that Se contributes to the stabilization of cucumber cell membrane and the reduction of ion leakage by promoting the synthesis of protective compounds and enhancing antioxidant enzyme activity. Moreover, grafting onto pumpkin resulted in increased salinity tolerance of cucumber through reduced Na uptake and translocation to the scion. CONCLUSION: In conclusion, the results highlight the effectiveness of Se biofortification and grafting onto pumpkin in improving cucumber salinity tolerance. A sodium selenate concentration of 10 mg L-1 is suggested to enhance the salinity tolerance of grafted cucumbers. These findings provide valuable insights for the development of sustainable cultivation practices to mitigate the adverse impact of salinity stress on cucumber production in challenging environments.

Efficient flocculation pretreatment of coal gasification wastewater by halophilic bacterium Halovibrio variabilis TG-5.

The isolated halophilic bacterial strain Halovibrio variabilis TG-5 showed a good performance in the pretreatment of coal gasification wastewater. With the optimum culture conditions of pH = 7, a temperature of 46 °C, and a salinity of 15%, the chemical oxygen demand and volatile phenol content of pretreated wastewater were decreased to 1721 mg/L and 94 mg/L, respectively. The removal rates of chemical oxygen demand and volatile phenol were over 90% and 70%, respectively. At the optimum salinity conditions of 15%, the total yield of intracellular compatible solutes and the extracellular transient released yield under hypotonic conditions were increased to 6.88 g/L and 3.45 g/L, respectively. The essential compatible solutes such as L-lysine, L-valine, and betaine were important in flocculation mechanism in wastewater pretreatment. This study provided a new method for pretreating coal gasification wastewater by halophilic microorganisms, and revealed the crucial roles of compatible solutes in the flocculation process.

Gut Microbiota and Uremic Retention Solutes in Adults With Moderate CKD: A 6-Day Controlled Feeding Study.

OBJECTIVE: To determine serum and urine concentrations of the uremic retention solutes (URSs), indoxyl sulfate (IS), p-cresol sulfate (PCS), and trimethylamine N-oxide (TMAO), and gut microbiota composition in individuals with moderate chronic kidney disease (CKD) compared with matched adults without CKD in a 6-day controlled feeding study. DESIGN AND METHODS: This study was a secondary analysis in which 8 adults with moderate CKD were matched for age, sex, and race with 8 adults without CKD in a parallel-arm, 6-day controlled feeding study. IS, PCS, and TMAO were quantified using liquid chromatography-mass spectrometry in fecal samples, fasting serum, and fasting spot urine samples collected at the end of the feeding period. RESULTS: Fasting serum URS concentrations were 2.8 to 4.9x higher in CKD compared to controls (all P < .05). No differences were found in the composition of the gut microbiota between patients with and without CKD when analyzing samples for α-diversity, ß-diversity, and only minor abundance differences across taxa were apparent. Estimated glomerular filtration rate (eGFR) was inversely related to each serum URS in the whole cohort (all P < .01). However, within groups the relationships between eGFR and serum URS remained strong for CKD patients for IS and TMAO (both P < .05) but weakened for PCS (P = .10). eGFR was only correlated with urine PCS in the whole cohort (P = .03); within groups, no correlation for eGFR with any urine URS was observed. Only urine TMAO was higher in CKD compared to controls (P < .05). CONCLUSION: Serum URS concentrations are elevated in adults with CKD compared to matched non-CKD adults without differences in gut microbiota composition after consuming the same controlled study diet for 6 days. Future studies are needed to determine if specific dietary components may differentially alter the microbiota and URS.

Nonenzymatic RNA replication in a mixture of 'spent' nucleotides.

Nonenzymatic template-directed replication would have been affected by co-solutes in a heterogeneous prebiotic soup due to lack of enzymatic machinery. Unlike in contemporary biology, these reactions use chemically activated nucleotides, which undergo rapid hydrolysis forming nucleoside monophosphates ('spent' monomers). These co-solutes cannot extend the primer but continue to base pair with the template, thereby interfering with replication. We, therefore, aimed to understand how a mixture of 'spent' ribonucleotides would affect nonenzymatic replication. We observed the inhibition of replication in the mixture, wherein the predominant contribution came from the cognate Watson-Crick monomer, showing potential sequence dependence. Our study highlights how nonenzymatic RNA replication would have been directly affected by co-solutes, with ramifications for the emergence of functional polymers in an RNA World.

Compatible solutes determine the heat resistance of conidia.

BACKGROUND: Asexually developed fungal spores (conidia) are key for the massive proliferation and dispersal of filamentous fungi. Germination of conidia and subsequent formation of a mycelium network give rise to many societal problems related to human and animal fungal diseases, post-harvest food spoilage, loss of harvest caused by plant-pathogenic fungi and moulding of buildings. Conidia are highly stress resistant compared to the vegetative mycelium and therefore even more difficult to tackle. RESULTS: In this study, complementary approaches are used to show that accumulation of mannitol and trehalose as the main compatible solutes during spore maturation is a key factor for heat resistance of conidia. Compatible solute concentrations increase during conidia maturation, correlating with increased heat resistance of mature conidia. This maturation only occurs when conidia are attached to the conidiophore. Moreover, conidia of a mutant Aspergillus niger strain, constructed by deleting genes involved in mannitol and trehalose synthesis and consequently containing low concentrations of these compatible solutes, exhibit a sixteen orders of magnitude more sensitive heat shock phenotype compared to wild-type conidia. Cultivation at elevated temperature results in adaptation of conidia with increased heat resistance. Transcriptomic and proteomic analyses revealed two putative heat shock proteins to be upregulated under these conditions. However, conidia of knock-out strains lacking these putative heat shock proteins did not show a reduced heat resistance. CONCLUSIONS: Heat stress resistance of fungal conidia is mainly determined by the compatible solute composition established during conidia maturation. To prevent heat resistant fungal spore contaminants, food processing protocols should consider environmental conditions stimulating compatible solute accumulation and potentially use compatible solute biosynthesis as a novel food preservation target.

The role of hydrodynamics for the spatial distribution of high-temperature hydrothermal vent-endemic fauna in the deep ocean environment.

Active hydrothermal vents provide the surrounding submarine environment with substantial amounts of matter and energy, thus serving as important habitats for diverse megabenthic communities in the deep ocean and constituting a unique, highly productive chemosynthetic ecosystem on Earth. Vent-endemic biological communities gather near the venting site and are usually not found beyond a distance of the order of 100 m from the vent. This is surprising because one would actually expect matter ejected from high-temperature vents, which generate highly turbulent buoyancy plumes, to be suspended and carried far away by the plume flows and deep-sea currents. Here, we study this problem from a fluid dynamics perspective by simulating the vent hydrodynamics using a numerical model that couples the plume flow with induced matter and energy transport. We find that both low- and high-temperature vents deposit most vent matter relatively close to the plume. In particular, the tendency of turbulent buoyancy plumes to carry matter far away is strongly counteracted by generated entrainment flows back into the plume stem. The deposition ranges of organic and inorganic hydrothermal particles obtained from the simulations for various natural high-temperature vents are consistent with the observed maximum spatial extent of biological communities, evidencing that plume hydrodynamics exercises strong control over the spatial distribution of vent-endemic fauna. While other factors affecting the spatial distribution of vent-endemic fauna, such as geology and geochemistry, are site-specific, the main physical features of plume hydrodynamics unraveled in this study are largely site-unspecific and therefore universal across vent sites on Earth.

An Approach for the Estimation of Concentrations of Soluble Compounds in E. coli Bioprocesses.

Accurate estimations of the concentrations of soluble compounds are crucial for optimizing bioprocesses involving Escherichia coli (E. coli). This study proposes a hybrid model structure that leverages off-gas analysis data and physiological parameters, including the average biomass age and specific growth rate, to estimate soluble compounds such as acetate and glutamate in fed-batch cultivations We used a hybrid recurrent neural network to establish the relationships between these parameters. To enhance the precision of the estimates, the model incorporates ensemble averaging and information gain. Ensemble averaging combines varying model inputs, leading to more robust representations of the underlying dynamics in E. coli bioprocesses. Our hybrid model estimates acetates with 1% and 8% system precision using data from the first site and the second site at GSK plc, respectively. Using the data from the second site, the precision of the approach for other solutes was as fallows: isoleucine -8%, lactate and glutamate -9%, and a 13% error for glutamine., These results, demonstrate its practical potential.

Influence of Solid Solutions on the Al2024 High-Temperature Deformation Behavior.

The mechanical properties of 2024 aluminum alloy were studied after two different tempers. The T351 temper (solution heat treatment, stress relief, and natural aging) leads to high hardness and toughness. A thermal treatment consisting of heat-treating at 280 °C for 48 h and slow cooling in a furnace, named TT temper, was performed to increase the precipitate size and their separation while minimizing the amount of solutes in solid solution, which produced the minimum hardness for an overaged Al2024 alloy and a lower tensile flow stress than for the T351 temper. The flow stress strongly decreases and the elongation to failure strongly increases for both materials above 300 °C. Differences in strain rate at a given stress in the power law regime at all temperatures for both tempers and compared with pure aluminum are attributed to the influence of solutes in solid solutions, affecting both the glide and climb of dislocations. However, the stacking fault energy, SFE, alone does not account for the hot deformation behavior. Thus, it is the synergistic effect of various solutes that affects the entire deformation process, causing a decrease of three or four orders of magnitude in strain rate for a given stress with respect to the pure aluminum matrix values.

Micromonospora profundi TRM 95458 converts glycerol to a new osmotic compound.

Plant growth and agricultural productivity was greatly limited by soil salinity and alkalization. The application of salt-tolerant rhizobacteria could effectively improve plant tolerance to saline-alkali stress. Micromonospora profundi TRM 95458 was obtained from the rhizosphere of chickpea (Cicer arietinum L.) as a moderate salt-tolerant rhizobacteria. A new osmotic compound (ABAGG) was isolated from the fermentation broth of M. profundi TRM 95458. The chemical structure of the new compound was elucidated by analyzing nuclear magnetic resonance (NMR) and high-resolution mass (HRMS) data. M. profundi TRM 95458 could convert glycerol into ABAGG. The accumulation of ABAGG varied depending on the amount of glycerol and glycine added to the fermentation medium. In addition, the concentration of NaCl affected the ABAGG content obviously. The highest yield of ABAGG was observed when the salt content of the fermentation medium was 10 g/L. The study indicated that salt stress led to the accumulation of ABAGG using glycerol and glycine as substrates, suggesting ABAGG might aid in the survival and adaptation of the strain in saline-alkaline environments as a new osmotic compound.

A general overview of the multifactorial adaptation to cold: biochemical mechanisms and strategies.

Cold environments are more frequent than people think. They include deep oceans, cold lakes, snow, permafrost, sea ice, glaciers, cold soils, cold deserts, caves, areas at elevations greater than 3000 m, and also artificial refrigeration systems. These environments are inhabited by a diversity of eukaryotic and prokaryotic organisms that must adapt to the hard conditions imposed by cold. This adaptation is multifactorial and includes (i) sensing the cold, mainly through the modification of the liquid-crystalline membrane state, leading to the activation of a two-component system that transduce the signal; (ii) adapting the composition of membranes for proper functions mainly due to the production of double bonds in lipids, changes in hopanoid composition, and the inclusion of pigments; (iii) producing cold-adapted proteins, some of which show modifications in the composition of amino acids involved in stabilizing interactions and structural adaptations, e.g., enzymes with high catalytic efficiency; and (iv) producing ice-binding proteins and anti-freeze proteins, extracellular polysaccharides and compatible solutes that protect cells from intracellular and extracellular ice. However, organisms also respond by reprogramming their metabolism and specifically inducing cold-shock and cold-adaptation genes through strategies such as DNA supercoiling, distinctive signatures in promoter regions and/or the action of CSPs on mRNAs, among others. In this review, we describe the main findings about how organisms adapt to cold, with a focus in prokaryotes and linking the information with findings in eukaryotes.