Search Results (533)

The Azores are characterized by intense volcanic activity, creating unique environments such as fumarole sites, where geothermal gases and high temperatures drive distinct chemical and biological processes. To investigate small-scale heterogeneity within such a site, six visually distinct samples were collected within a 30 cm radius at an active fumarole on São Miguel Island. The samples were analyzed for elemental and mineralogical composition, bacterial lipid biomarkers (PLFAs), and microbial community structure using a novel DNA separation technique to specifically target the living microbiome. Despite mineralogical similarities across all samples—predominantly composed of alunite, alkali-feldspar, and quartz—significant microbial heterogeneity was observed. Both PLFA and bacterial iDNA analyses revealed distinct microbial communities associated with specific conditions indicated by the specific colors: red and brown samples were dominated by Proteobacteria and Actinobacteriota, yellow and green by Thermoplasmatota and Actinobacteriota, and white and gray by Crenarchaeota. Interestingly, the gray samples exhibited a broader microbial composition, sharing some taxa with all other samples. These striking color variations are likely driven by differences in both specific mineral composition and microbial pigmentation, reflecting localized biogeochemical processes. Our findings demonstrate that extreme microbial heterogeneity can occur over remarkably small spatial scales within fumarolic systems, underscoring the complex interplay between chemical and biological factors in these dynamic volcanic habitats. Full article

The efficacy of enzyme therapy is limited by their poor stability under physiological conditions. Thermostable enzymes, derived from extremophilic organisms or generated by advanced protein engineering, offer a revolutionary solution to this long-standing challenge. They are widely used in industrial biocatalysis. Their therapeutic applications are poorly investigated and spread across diverse disciplines. While most applications are in the preclinical stages, emerging evidence from animal models demonstrates proof-of-concept for thermostable antioxidant enzymes in cardiovascular, neurodegenerative, and inflammatory diseases. This review critically assesses the translational landscape, distinguishing between established therapeutic enzymes (e.g., asparaginase, PEGylated SOD) and emerging experimental candidates. This narrative review consolidates existing knowledge about thermostable enzyme engineering and their emerging functions as molecular therapies, particularly in oxidative stress-related diseases. This review synthesizes recent advances in structural biology, computational protein design, biomaterials engineering, and translational antioxidant strategies, highlighting how breaking down disciplinary barriers is accelerating the development of sustainable and self-regenerating antioxidant platforms. By integrating molecular precision with systems-level therapeutic design, engineered thermostable antioxidant enzymes exemplify the future of biological development, where multidisciplinary collaboration drives innovation against oxidative stress-driven pathologies. Engineered thermostable enzymes provide a versatile basis for next-generation therapeutics, with the potential to address medical needs through improved stability, targeted activity, and multifunctional design. Full article

The increasing demand for lithium (Li), cobalt (Co), and rare earth elements (REEs) driven by battery technologies, electrification and renewable energy systems has intensified the interest in recovery pathways as an alternative to conventional mining. High-salinity mine waters—including lithium brines, geothermal fluids, and metallurgical effluents—represent both an environmental liability and a significant secondary resource for metal recovery. However, extreme ionic strength, complex metal speciation, and strong competition from major ions severely limit the efficiency and selectivity of traditional extraction technologies. Microalgae and cyanobacteria are promising biological agents for metal recovery via biosorption, bioaccumulation, and extracellular polymeric substance (EPS)-mediated binding, especially in saline and hypersaline systems. This review synthesises current knowledge on microalgal-based recovery of Li, Co, and REEs from high-salinity waters, emphasising co-design principles that integrate strain physiology, their adaptation to the extreme operating conditions, water chemistry, and process engineering. Halotolerant and extremophilic taxa—Nannochloropsis oceanica, Galdieria sulphuraria, and Synechococcus elongatus—are examined as representative models for complementary metal-binding mechanisms and operational niches. Limitations such as weak affinity for lithium, competitive ion suppression, desorption inefficiencies, and scale-up challenges are discussed. Emerging strategies such as modular multi-strain systems, hybrid bio-physicochemical platforms, and biomass valorisation are also addressed. The review concludes that microalgal systems, when co-designed for selectivity and resilience, can contribute to the strategic recovery of critical materials that align with EU, UK and US policies. Full article

Soil salinity inhibits biological nitrogen fixation (BNF) in legumes, compromising nitrogen nutrition and crop productivity. This study evaluated whether two halotolerant Mesorhizobium ciceri strains (S1, S2) can sustain BNF and alleviate moderate salt stress (100 mM NaCl) in three Tunisian chickpea (Cicer arietinum L.) cultivars (Amdoun, Béja 1, and Nour). Inoculated and non-inoculated plants were grown under controlled conditions. Salinity reduced shoot dry weight by 37.5–42% and severely impaired nodulation (≈60% reduction) in non-inoculated plants. Bacterial inoculation significantly increased germination rate, shoot and root biomass, and nodule number compared to non-inoculated salt-stressed controls. Improved nodulation corresponded to better nitrogen nutrition, reflected by higher leaf chlorophyll content (a proxy for nitrogen status). However, direct measurements of nitrogenase activity (e.g., acetylene reduction assay) are needed to confirm enhanced BNF. Inoculated seedlings also exhibited lower oxidative stress markers (hydrogen peroxide and malondialdehyde) and enhanced antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase), indicating reduced reactive oxygen species damage. Cultivar-specific responses were observed: Amdoun responded best to S1, Béja 1 to S2 for biomass recovery, while Nour showed strong antioxidant induction but limited growth gain. We conclude that halotolerant M. ciceri strains improve chickpea performance under salt stress primarily by sustaining BNF and nodulation, thereby maintaining nitrogen nutrition. Strain–cultivar compatibility is critical for optimizing this bio-inoculant strategy in saline agroecosystems. Our findings identify the combination of cultivar Béja 1 with strain S2 as the most promising for biomass recovery under moderate salinity, providing a practical, strain–cultivar matching framework that can guide the development of effective bio-inoculants for chickpea production in salt-affected areas of Tunisia and similar Mediterranean regions. Full article

Inorganic carbon availability is an underexplored factor influencing extracellular emulsification-associated responses in haloalkaliphilic bacteria. Here, we show that Vreelandella zhaodongensis BS253 exhibits distinct physiological and transcriptional responses to CO₂ enrichment and bicarbonate supplementation, accompanied by condition-dependent changes in emulsification activity. Both moderate CO₂ enrichment (5–10%) and NaHCO₃ supported high emulsification values (E24 > 60%). However, CO₂ favored higher emulsification activity relative to biomass, whereas NaHCO₃ promoted greater biomass accumulation and elevated absolute activity. Transcriptomic profiling revealed extensive condition-dependent reprogramming, particularly involving membrane transport, envelope-associated functions, and genes annotated as related to exopolysaccharide biosynthesis. Integrative phenotype-guided analyses prioritized candidate genes statistically associated with the emulsification phenotype. The extracellular emulsification-active material remained active across a broad range of salinity, temperature, pH, and pressure, demonstrating pronounced physicochemical robustness. Together, these findings indicate that inorganic carbon availability modulates emulsification activity and associated transcriptional responses in a haloalkaliphile and highlight extremophilic bacteria as promising platforms for sustainable bioprocesses based on inorganic carbon inputs. Full article

Industrial activities have contributed substantially to the global economy but have also resulted in the release of hazardous substances into the environment. This systematic review aimed to identify extremophilic or extremotolerant bacteria capable of surviving high metal concentrations and actively remediating elevated levels of Cd, Cr, Cu, Fe, Pb, and Zn. Following the PRISMA guidelines, a qualitative systematic review was conducted in the Web of Science and Scopus databases for studies published between 2000 and 2025 (last search: 5 January 2026). The synthesized dataset revealed distinct ecological and functional roles across different taxonomic levels. At the family level, Carnobacteriaceae, Cyclobacteriaceae, and Erythrobacteraceae were predominantly associated with high metal tolerance (“exposed” profiles) in alkaline environments. Conversely, at the genus level, Acidithiobacillus, Phenobacterium, Microbulbifer, and Roseobacter demonstrated high active remediation capacities in acidic settings through bioleaching, precipitation, or biosorption. Species such as Bacillus subtilis and Acidithiobacillus ferrooxidans exhibit a dual profile combining environmental tolerance and high bioremediation performance. These findings highlight methodologically heterogeneous studies, necessitating standardized experimental validation prior to large-scale technological deployment. Full article

Salinity is a dominant ecological driver shaping microbial community structure and function in hypersaline environments. Here, we investigated transcriptional responses to rapid salinity fluctuations using metatranscriptomic analyses of an intermediate-salinity brine sample from the Santa Pola solar salterns (Alicante, Spain). To this end, two experimental conditions were applied: salinity increase (12.4% to 17%) and salinity dilution (12.4% to 7%). Differential gene expression, functional enrichment, and protein isoelectric point (pI) distributions were analyzed to characterize osmoadaptive mechanisms. Salinity increase triggered a stress-dominated response characterized by upregulation of compatible solute biosynthesis (e.g., glycine betaine and ectoine), protein turnover, and chaperone activity, alongside repression of translation, energy metabolism, and transport systems. In contrast, salinity dilution induced metabolic reactivation, including enhanced translation, energy production, and osmolyte degradation pathways, indicating recovery from osmotic stress. Functional shifts were accompanied by changes in proteome physicochemical properties, with increased salinity promoting a shift toward higher pI proteins, consistent with salt-out strategies. These findings reveal a highly dynamic and asymmetric transcriptional plasticity, where osmotic upshift imposes stronger constraints than downshift, driving coordinated metabolic reprogramming and proteome restructuring in intermediate-salinity microbial communities. Full article

The search for extraterrestrial life has traditionally focused on environments where liquid H₂O is stable over long timescales, such as subsurface aquifers, hydrothermal systems, or ice-rich deposits. However, many planetary bodies are characterized by active cycles of particulate transport involving either mineral dust or atmospheric aerosols. In planetary science, these are commonly distinguished as refractory particles (non-volatile mineral dust) and volatile or mixed aerosol particles, including condensates such as ices, organics, or acidic droplets. Here, we propose the concept of planetary aerobiomes, defined as distributed particle-associated microbial persistence and dispersal systems in extraterrestrial environments. In this framework, refractory mineral particles may act as mobile particle-associated microenvironments that could support microbial survival and dispersal, while in some cases also providing partial physical shielding from environmental stressors. Drawing on observations from terrestrial dust-associated microbiomes and mineral–microbe interactions, particle-associated systems may represent previously overlooked ecological substrates in planetary environments. Rather than replacing models centred on environments with persistent liquid H₂O, this perspective expands them by considering particle-associated microenvironments as transient but potentially relevant biosignature-preservation niches in arid, dust-dominated worlds such as Mars, as well as in aerosol-rich environments including Titan, Venus, and icy moons. We further discuss the implications for life-detection strategies, highlighting atmospheric particles as potential reservoirs of biosignatures, and consider their relevance for applied microbiology, including in situ resource utilization (ISRU) and bioregenerative life-support systems (BLSS). Beyond astrobiological implications, understanding microbial persistence within particle-associated extreme environments may provide useful models for applied microbiology, including stress-resilient microbial engineering, biomining, contamination control, and bioregenerative technologies for space exploration. Full article

Persistently high levels of abiotic stress define extreme environments. Even for adapted extremophiles, we argue this stress remains a continuous physiological challenge, necessitating energetically costly homeostasis. Crucially, this persistent pressure drives a self-reinforcing feedback loop across biological scales: it accelerates genomic evolution and concurrently reshapes ecological network architecture. Genomic innovations provide new traits for network reconfiguration, while the restructured network acts as a selective filter guiding subsequent evolution. This loop underpins extreme ecosystem resilience—the capacity for stress-induced adaptive restructuring. We synthesize mechanisms of this stress-adaptation interplay, propose testable hypotheses and outline experimental evolution approaches to validate this predictive framework for microbial responses to global change. Full article

Climate change, soil degradation, and the disruption of global nutrient cycles are placing unprecedented pressure on agricultural systems and global food security. These challenges are increasingly recognized as central concerns for planetary health, as agriculture simultaneously depends upon and alters critical Earth system processes. Microbe-based agricultural inputs (including biofertilizers, biostimulants, and biocontrol agents) have been widely promoted as climate-smart solutions capable of enhancing productivity, resilience, and environmental sustainability. However, despite rapid scientific and commercial advances, their performance in the field remains highly variable and strongly context-dependent. This review critically examines the evidence base underpinning climate-smart microbial solutions, with a particular focus on their capacity to confer climate resilience across diverse crops, soils, and climatic conditions. We synthesize current knowledge on the functional roles of beneficial microorganisms, including extremophilic and stress-adapted taxa, while highlighting key biological, technological, ecological, and socio-economic constraints that limit predictability and scalability. Special attention is given to evidence gaps related to long-term field performance, ecosystem-level impacts, and the trade-offs associated with widespread microbial deployment. We further assess recent innovations such as synthetic microbial consortia, microbiome engineering, advanced formulations, and data-driven decision tools. Then we highlight how these new technologies may address context dependency but still need validation under real-world conditions. Finally, we discuss policy, regulatory, and capacity-building considerations required to responsibly integrate microbial solutions into climate-smart agriculture frameworks. Overall, this review argues that microbial inoculants should be viewed not as universal inputs but as context-specific tools whose successful deployment depends on robust evidence, ecological sensitivity, and system-level integration. Advancing microbial solutions for agriculture will therefore require aligning technological innovation with broader planetary health objectives, ensuring that efforts to enhance agricultural productivity also support long-term ecosystem stability and resilience. Full article

Hypersaline environments are unique ecosystems harboring specialized microbial communities with significant biotechnological potential. This study provides a comprehensive characterization of the taxonomic diversity and functional potential of two Tunisian salterns, Abbassia (Kerkennah) and Thyna (Sfax), using an integrated approach that combines 16S/18S rRNA gene amplicons (Illumina and full-length Nanopore) with shotgun metagenomics. Taxonomic profiling revealed a high species richness (S ≈ 1250 taxa); however, the Abbassia site was characterized by extreme taxonomic polarization, with over 95% of the community dominated by specialized halophilic Bacillota (Salinicoccus and Jeotgalicoccus). In contrast, Thyna exhibited a more even distribution dominated by Pseudomonadota and methanogenic Archaea. Beyond taxonomy, functional annotation via the HUMAnN 3.0 pipeline identified site-specific metabolic specializations. Abbassia was enriched in biosynthetic pathways and robust stress-response mechanisms, including ectoine biosynthesis and ppGpp-mediated stringent response, reflecting adaptation to stable hypersaline conditions. Conversely, Thyna’s microbiome prioritized energy extraction and nutrient recycling, with a high abundance of fermentation and glyoxylate cycle pathways. These findings demonstrate that environmental filtering shapes not only the microbial structure but also the metabolic landscape, highlighting the ecological plasticity of microbial life in extreme Tunisian salterns. Full article

Aminoglycoside resistance is commonly mediated by enzymatic modification, target alteration, or efflux mechanisms; however, acquired resistance has not been characterized in radiation-resistant Deinococcus species. Here, we investigated the occurrence and genomic context of acquired aminoglycoside resistance genes in all publicly available Deinococcus radiodurans genomes. A total of 19 genomes were screened using ResFinder and CARD, followed by comparative genomic analyses. The aadA1 gene was identified in two genomes, being located on the plasmid pSP1 in strain R1 dM1, a known shuttle vector used for genetic manipulation. In contrast, aadA1 was found on a chromosomal contig in strain DRR11, suggesting a possible assembly artifact. Additionally, the aph(3′)-Ia gene was detected in three genomes within a conserved chromosomal region that lacks this gene in reference strains. Sequence similarity analyses indicated that aph(3′)-Ia is associated with laboratory vectors, being consistent with a potential non-natural origin. Considering the high recombination capacity and genomic plasticity of D. radiodurans, these findings suggest that the detected aminoglycoside resistance genes may be derived from laboratory constructs, potentially combined with assembly inconsistencies or chromosomal integration events. Therefore, this study highlights the importance of integrating genomic context with molecular and evolutionary plausibility to avoid misinterpretation of antimicrobial resistance in extremophiles and model organisms, and underscores the importance of complementary raw-read analyses to distinguish natural acquisition from technical or laboratory-derived origins. Full article

Cystic fibrosis (CF)-associated lung infections caused by Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) remain difficult to treat due to multidrug resistance and the redox instability of the pulmonary environment, which can impair antibiotic efficacy. In this study, we investigated alvinellacin (ALV), a disulfide-stabilized β-hairpin antimicrobial peptide (AMP) derived from the deep-sea polychaete Alvinella pompejana (A. pompejana), as a potential therapeutic agent naturally adapted to redox-fluctuating conditions. The antibacterial and antibiofilm activities of ALV were evaluated against multidrug-resistant (MDR) clinical isolates under CF-like reducing conditions (6 mM dithiothreitol (DTT)). Circular dichroism (CD) analysis showed that DTT did not alter the β-hairpin secondary structure of ALV, supporting its structural stability in CF-like environments. Mechanistic analyses included pore-forming assay, membrane interaction studies, scanning electron microscopy (SEM), lipid-binding assays, cytotoxicity testing, and resistance induction assays, while in vivo efficacy was assessed using the Galleria mellonella infection model. ALV demonstrated strong bactericidal activity that was maintained in the presence of NaCl or human serum. ALV did not induce bacterial resistance and effectively inhibited early-stage biofilm formation and disrupted preformed biofilms, including those of the clinical isolate, even under reducing conditions. The peptide showed selective permeabilization of bacterial membranes linked to its stronger affinity for bacterial membrane lipids and negligible interaction with host-like membranes, with no observed cytotoxicity. In vivo, ALV significantly improved survival in infected larvae. These findings highlight ALV as a promising redox-resilient antimicrobial candidate for treating MDR CF lung infections. Full article

Dental implants are widely used to replace missing teeth, but peri-implantitis remains a major biological complication associated with bacterial biofilm formation on implant surfaces. The increasing incidence of peri-implant infections underscores the need for alternative antimicrobial strategies that effectively decontaminate complex titanium implant surfaces. This study evaluated the inhibitory effect of low-temperature microwave argon plasma on bacteria in an experimental model simulating peri-implant conditions and compared the responses of microorganisms with different biological characteristics. A 3D-printed mandibular bone segment model with an inserted Straumann BLX Roxolid^® dental implant was used to reproduce the peri-implant environment. Bacterial suspensions of Streptococcus mutans NBIMCC 1786 and the extremophilic bacterium Chromohalobacter canadensis NBIMCC 9077 have been exposed to a microwave non-equilibrium argon plasma jet (2.45 GHz, atmospheric pressure) for 1–7 min. Optical density measurements and colony growth analysis were used to assess antimicrobial effects. Plasma treatment induced a pronounced reduction in bacterial growth during the early post-treatment period. In C. canadensis, growth inhibition reached a plateau (~47–55% at 24 h) regardless of exposure time. In contrast, S. mutans showed a nonlinear response, with stable inhibition after short exposures (1–3 min) and partial recovery after longer treatments (5–7 min). These findings indicate that microwave argon plasma exhibits significant antimicrobial activity under controlled in vitro conditions, although its effectiveness depends on microorganism-specific biological characteristics. Because the present model was based on simplified single-species systems, direct clinical extrapolation remains limited and should be addressed in future studies using polymicrobial peri-implant biofilm models. Full article

Chloroidium saccharophilum is a resilient green microalga with a broad ecological distribution and an increasing biotechnological interest due to its tolerance of extreme environmental conditions. In this study, a sample of C. saccharophilum from the Laguna Blanca aquifer (Magallanes, southern Chile) was physiologically and phylogenetically characterized. This is the first confirmed evidence of this strain in the Southern Cone. Molecular identification based on ITS rDNA sequencing and ITS2 secondary structure analysis confirmed its taxonomic location, showing high similarity with reference strains and no compensatory base changes. Growth performance was analyzed under controlled laboratory conditions and under outdoor desert cultivation in the Atacama Desert, focusing on temperature, salinity, nutrients limitation, and high solar irradiance operational conditions. The strain exhibited optimal growth at 22 °C under laboratory conditions and demonstrated a strong tolerance to high salinity (150 g L⁻¹ NaCl). Outdoor raceways cultivation revealed a negative relationship between temperatures above 25 °C and biomass accumulation, while nutrients depletion and strong irradiance caused moderate carotenoid accumulation. However, the low amount of carotenoid yields remained constant, even under combined stress conditions. In general, the results highlight the ecological adaptability and the stress tolerance of C. saccharophilum, supporting its potential application in saline bioprocesses and bioremediation. Nevertheless, the limited production of carotenoid synthesis suggests that additional or combined stress strategies will be required to enhance the production of high-value metabolites. This study expands the biogeographical knowledge of C. saccharophilum and provides a physiological baseline for future optimization studies in extreme and Mars-analog environments. Full article