Search Results (146)

Bacterial self-healing concrete has emerged as a bio-based strategy to enhance the durability of cementitious materials and reduce the environmental impact associated with premature infrastructure deterioration. Its functional principle relies on microbially induced calcium carbonate precipitation (MICP), through which bacterial metabolism promotes CaCO₃ deposition within cracks. However, self-healing efficiency cannot be explained solely by mineral precipitation capacity. Concrete is a restrictive microbial environment characterized by alkalinity, desiccation, osmotic stress, nutrient limitation and physical confinement. Therefore, effective crack sealing requires a coordinated sequence involving bacterial survival, sporulation, germination, metabolic reactivation, biofilm-associated mineral nucleation and localized biomineralization. This integrative narrative review synthesizes mechanistic, material and biosafety evidence on bacterial self-healing concrete, focusing on spore-forming bacteria such as Bacillus subtilis and related taxa, including Paenibacillus. The evidence indicates that stress tolerance, germination signaling, calcium handling, biofilm establishment and stability, and encapsulation-mediated microenvironmental control are key determinants of performance, but remain insufficiently integrated into materials-oriented studies. Large-scale implementation also requires preventive assessment of strain persistence, genetic stability, horizontal gene transfer, environmental microbiome interactions and life-cycle exposure scenarios. Bacterial self-healing concrete should therefore be understood as a living or bioactive material system whose responsible development depends on the integration of microbiology, molecular biology, materials science, civil engineering, environmental risk assessment, occupational health, and public health. Full article

The ongoing development of subtractive options for indirect restorations places clinicians in a position that requires adaptation, understanding and choosing of the most suitable option for the long-term survival of the restoration. Mechanical parameters represent important indicators of long-term success. Consequently, this research aimed to assess the impact of water sorption on the mechanical properties of two direct resin composites, Gradia Direct Anterior A2 and Filtek Z550 A2 and three CAD/CAM subtractively manufactured dental resin composites, Vita Enamic, Brilliant and Cerasmart. A total of one hundred specimens (50 control, 50 underwent this protocol: dehydration, immersion in distilled water for 30 days and then re-desiccation), standardized to the dimensions of 14 mm × 4 mm × 1.2 mm were subjected to three-point bending test (based on ISO 4049:2019 and ISO 6872:2015), in order to find out the flexural strength and the elastic modulus of the material at the breaking point. Then, the fractured sample surfaces were fractographical analyzed. Using the two-parameter Weibull approach, the Weibull modulus (m) and the characteristic strength (σ₀) were evaluated. In this investigation, the elastic modulus varied from 5.8 (Gradia Control) to 20.31 (Vita Degraded) GPa, with the upper limit close to the values of natural dentin (17.7–29.8 GPa). The values of flexural strength ranged from 174.47 (Brilliant Control) to 79.2 (Gradia Control), subtractively processed materials demonstrating higher flexural strength and elastic modulus values than the direct resin composites, which is related to their high inorganic filler content. All material groups, except for Gradia Control, had a flexural strength more than the 80 MPa minimum value needed to sustain masticatory force. The dehydration and hydration cycles did not have a statistically significant influence on the mechanical properties of the material. The fractographic analysis revealed fracture patterns and features associated with the microstructure, with the PICN category material being particularly notable. Weibull analysis revealed that the direct resin composite materials exhibited higher reliability, lower data scatter and CAD-CAM materials showed greater characteristic strength, with a notably high performance of the nano-hybrid direct resin composite. Full article

Desiccation, ionizing radiation, ultraviolet exposure, and oxidative stress impose severe physicochemical stress that threatens the integrity of both DNA and RNA. Water loss promotes molecular crowding, protein and membrane destabilization, and the accumulation of reactive oxygen species (ROS), while rehydration can intensify oxidative injury and expose lesions accumulated during metabolic suppression. As a result, stress-tolerant metazoans must do more than survive water loss: they must also protect, monitor, and restore nucleic-acid integrity. Here, we review how tardigrades, bdelloid rotifers, Artemia, nematodes, and selected insect species preserve genomic and transcriptomic integrity under extreme dehydration, oxidative stress, and radiation-related insults. We compare conserved defence systems, including antioxidant enzymes, trehalose, LEA proteins, heat shock proteins, and core DNA repair pathways. These pathways include base excision repair, nucleotide excision repair, homologous recombination, and non-homologous end joining. We then examine how these conserved mechanisms contrast with lineage-specific innovations, such as the tardigrade proteins Dsup, TDR1, and TRID1, as well as the unusual genome plasticity of bdelloid rotifers. We argue that stress biology of these organisms is best understood through a framework that distinguishes damage prevention during drying from repair and recovery during rehydration. In this framework, extremotolerant metazoans provide biologically informative models for understanding oxidative nucleic-acid damage, redox defence and the molecular logic underlying radioprotection and dry-state preservation. Full article

This study reports, for the first time, changes in the microbiome community associated with anhydrobiosis in two tardigrade species of the genus Paramacrobiotus. To identify bacteria linked to the anhydrobiosis phenomenon and to track microbiome changes under anhydrobiotic stress, next-generation sequencing of bacterial 16S rRNA genes was conducted. Microbiome profiling was performed across various developmental and physiological stages of tardigrades, including: eggs; active adult specimens (both before and after 7, and 120 days of anhydrobiosis, referred to as short- and long-term anhydrobiosis, respectively); specimens in the desiccated tun stage; dead specimens following long-term anhydrobiosis (no dead specimens were observed after short-term anhydrobiosis); and the culture medium. It was shown that the microbiome community varied among stages, with high stage-specificity. Several bacterial genera were identified that may assist the host during anhydrobiosis, potentially through biofilm formation and by supporting stress-protective mechanisms such as heat shock protein expression and trehalose synthesis in eggs and tuns. These findings reveal that microbiota may contribute to anhydrobiotic survival in tardigrades, providing novel insights into host–microbe interactions under extreme environmental stress. Full article

Green roofs are increasingly recognized as nature-based solutions that enhance urban resilience by supporting biodiversity, regulating microclimates, and mitigating stormwater runoff. However, their performance—particularly in extensive, lightweight systems—is often constrained by drought stress, which limits plant survival and ecosystem functioning under climate change. While substrate composition has been widely investigated in this context, the role of wind as a co-driver of drought impacts remains poorly understood. In this study, we examined how moderate wind interacts with substrate properties to shape drought responses in green roof vegetation. Using three non-succulent species (Plantago maritima, Pilosella officinarum, and Festuca rubra), we quantified substrate and plant water balance, physiological performance, wilting dynamics, and survival under prolonged drought conditions. Our results demonstrate that wind significantly accelerates drought effects—regardless of species or substrate—by intensifying substrate desiccation, with critical moisture thresholds reached at 6–8%. While wind alone did not impair plant performance under well-watered conditions, its interaction with drought markedly reduced survival time and increased physiological stress. Although general response patterns were consistent across species, subtle interspecific differences indicate that plant selection for green roofs should account for combined drought and wind exposure. These findings highlight wind as an overlooked but critical factor in the design and evaluation of resilient green roof systems and potentially contribute to a more comprehensive understanding of vegetation performance in urban nature-based solutions under climate stress. Full article

Weathered serpentinites are extreme lithobiontic environments characterized by oligotrophy, high heavy metal content, and desiccation stress; yet, the adaptive mechanisms of colonizing actinobacteria remain poorly understood. This study aimed to isolate and characterize xerotolerant actinobacteria from serpentinite and to profile their secondary metabolites involved in stress tolerance. Three lithobiontic strains were isolated and identified by whole-genome sequencing (dDDH and ANI) as Rhodococcus oxybenzonivorans SK11, Paenarthrobacter nitroguajacolicus SK18, and Rhodococcus qingshengii SK25. Desiccation tolerance was assessed using PEG-8000, siderophore production on CAS agar with metal substitution (Fe³⁺, Al³⁺, Cu²⁺, Ga³⁺), and biosurfactant activity via emulsification assays. Genome mining identified biosynthetic gene clusters for compatible solutes, siderophores, and biosurfactants. All strains maintained viability at 50% PEG. Compatible solute pathways included ectoine (ectABC) in SK18 and SK25, glycine betaine (gbsAB) only in SK18, and trehalose (TreYZ) and proline (ProABC) pathways in all three. Genome mining of Rhodococcus strains revealed a number of NRPS-dependent clusters, some of which are predicted to encode siderophores (rhodochelin, heterobactins), while SK18 used an NRPS-independent desferrioxamine E pathway together with a unique lanthipeptide cluster. Biosurfactant production was condition-dependent, with SK25 achieving complete emulsification (E₂₄ = 100%) in hexadecane-supplemented medium. These findings demonstrate that weathered serpentinite actinobacteria employ an extracellular molecular repertoire of compatible solutes, siderophores, and biosurfactants to survive extreme oligotrophy, desiccation, and metal stress. Full article

Desiccation tolerance is a critical adaptive trait that enables plants to survive extreme water loss, yet its physiological basis in tomato and its wild relatives remains poorly understood. In this study, chlorophyll a fluorescence imaging was used as a reliable tool to evaluate photosystem II (PSII) response to progressive desiccation. The analysis was conducted in cultivated tomato (Solanum lycopersicum) and five wild relatives (Solanum chilense, Solanum habrochaites, Solanum peruvianum, Solanum pimpinellifolium, and Solanum pennellii). Detached leaves were subjected to controlled desiccation for up to 50 h. During this period, tissue moisture content (TMC), relative water content (RWC), PSII photochemical efficiency [Fv/Fm; maximum quantum yield (QY_max)], minimal fluorescence (F0), maximal fluorescence (Fm), and variable fluorescence (Fv) were monitored to assess changes in photosynthetic performance. Desiccation caused a significant, moisture-dependent decline in PSII efficiency across all species, with QY_max showing a strong linear relationship with RWC (R² = 0.80–0.90). Interspecific variation was evident as S. chilense, S. habrochaites, S. peruvianum, and S. pimpinellifolium exhibited rapid PSII impairment, while S. lycopersicum showed moderate tolerance. In contrast, S. pennellii maintained higher PSII stability, with 50% loss of efficiency occurring only at lower RWC (30–35%). Overall, chlorophyll fluorescence imaging effectively captured functional diversity in desiccation tolerance, highlighting S. pennellii as a valuable genetic resource for improving drought resilience in tomato. Full article

Acinetobacter baumannii is a leading cause of healthcare-associated infections and is classified among the highest-priority antimicrobial-resistant pathogens. Its clinical success reflects the convergence of antimicrobial resistance (AMR) and biological traits that promote environmental persistence and transmission. Acinetobacter baumannii has undergone a remarkable transformation over the past few decades, evolving from a relatively obscure environmental bacterium into a globally recognized multidrug-resistant pathogen. Its prevalence in healthcare settings, particularly intensive care units, has made it a leading cause of ventilator-associated pneumonia, bloodstream infections, wound infections, and urinary tract infections. Beyond its antibiotic resistance, the bacterium’s ability to persist in hospital environments and adapt to host defences has amplified its clinical significance. Recent research has uncovered complex networks of virulence factors, regulatory systems, and metabolic strategies that enable A. baumannii to thrive in hostile environments and evade host immunity, providing new insights into its pathogenesis and potential therapeutic vulnerabilities. This review summarizes the main mechanisms underlying its pathogenicity, including desiccation tolerance, biofilm formation, disinfectant resistance, metal acquisition, motility, and the ability to enter viable but non-culturable states. In A. baumannii, AMR functions as a pathogenesis-adjacent trait, enhancing survival and clonal dissemination through genomic plasticity, resistance islands, efflux systems, and envelope remodeling. Key resistance pathways involve carbapenem-hydrolyzing oxacillinases, metallo-β-lactamases, permeability defects, and multidrug efflux, often coexisting within high-risk clones. From a clinical perspective, management of carbapenem-resistant strains requires accurate infection diagnosis, reliable susceptibility testing, site-specific and PK/PD-optimized therapy, and early reassessment. Overall, the success of A. baumannii reflects the integration of resistance and persistence within healthcare ecosystems, highlighting the need for coordinated strategies combining stewardship, infection control, improved diagnostics, and anti-biofilm or anti-virulence approaches. Full article

Forest plantations, including those of Norway spruce, are increasingly threatened by drought in Central Europe. One of the measures understating this threat might be the use of drought-mitigative additives at planting. The effects of induced water limitation and the application of hydrogel Agrisorb and commercial ectomycorrhizal fungi (EMF) inoculum Ectovit on the development of 2 + 1 spruce seedlings were estimated in this study. The root systems of 2 + 0 seedlings were treated with the additives, along with their spring transplantation into peat-filled pots. The seedlings were then exposed throughout the entire growing season either to full watering (FW)—volumetric soil water content 70%, reduced watering (RW)—water content 40%, periodic watering (PW)—substrate rehydrated to 70% after drying to the wilting point (21%), or remained non-watered (NW). Survival, growth and chlorophyll fluorescence of the seedlings decreased proportionally to the increased drought intensity, while the highest root-to-shoot ratio and EMF colonization of roots occurred under PW and RW, respectively. NW seedlings died after 9 weeks of desiccation, whereas the EMF inoculum prolonged the survival time by one week. Ectomycorrhizas were formed predominantly with native EMF in all the treatments; nevertheless, compared with the uninoculated control, the formation of a treatment-specific EMF root morphotype and increased EMF colonization under PW and RW were observed on the inoculated seedlings. Both the EMF inoculum and the hydrogel increased survival under PW by approximately 15% but did not significantly affect growth, regardless of the watering regime. These results are limited to the experimental conditions and suggest a more dominant effects of the watering regimes compared with the additives tested. Full article

Liquid is a fundamental requirement for life as we understand it, but whether that liquid has to be water is not known. We propose the hypothesis that ionic liquids (ILs) and deep eutectic solvents (DES) constitute a class of non-aqueous planetary liquids capable of persisting on a wide range of bodies where stable liquid water cannot exist. This hypothesis is motivated by key physical properties of ILs and DES. Many exhibit vapor pressures orders of magnitude lower than that of water and remain liquid across exceptionally wide temperature ranges, from cryogenic to well above terrestrial temperatures. These properties permit stable liquids to exist where liquid water would rapidly evaporate or freeze and outside of bulk phases as persistent microscale reservoirs—such as thin films and pore-filling droplets. In other words, ILs and DES can persist in environments without requiring oceans, thick atmospheres, or narrowly regulated climate conditions. We further hypothesize that ILs and DES could act as solvents for non-Earth-like life, based on their polar nature and the demonstrated stability and functionality of proteins and other biomolecules in ionic liquids. More speculatively, our hypothesis extends to the idea that ILs and DES could enable prebiotic chemistry by providing long-lived, protective liquid environments for complex organic molecules on bodies such as comets and asteroids, where liquid water is absent. Additionally, based on the occurrence of DES-like mixtures as protective intracellular liquids in desiccation-tolerant plants, we propose that ILs and DES might be solvents that life elsewhere purposefully evolves. We review protein and other biomolecule studies in ILs and DES and outline planetary environments in which ILs and DES might occur by discussing available anions and cations. We present strategies to advance the IL/DES solvent hypothesis using laboratory studies, computational chemistry, planetary missions, analysis of existing spectroscopic datasets, and modeling of liquid microniches and chemical survival on small bodies. Full article

The aetiology of invasive candidiasis is undergoing substantial changes; traditionally, these mycoses have been considered to originate from endogenous reservoirs; however, the increasing prevalence of non-Candida albicans species, such as Candida parapsilosis and Candida auris (also named Candidozyma auris), is a cause of concern as they demonstrate significant exogenous transmission. This challenges the long-standing paradigm of endogenous origin in hospital settings. Unlike previous reviews primarily focused on clinical epidemiology, this work adopts a multidisciplinary perspective combining microbiological evidence with biomaterials science. We analyse how surface roughness, hydrophobicity, and polymer composition within the hospital “plastisphere” influence Candida adhesion and the formation of dry surface biofilms (DSBs). In this specific context, in contrast to C. albicans, primarily associated with mucosal colonisation, C. auris and C. parapsilosis exhibit distinctive adaptations that promote survival in healthcare environments, including pronounced cell surface hydrophobicity and the capacity to form dense cellular aggregates, which facilitate prolonged adherence to synthetic polymers used in medical devices. We also explore the biological mechanisms underlying this resilience, with particular emphasis on the development of dry surface biofilms and viable but non-culturable states. These phenotypic traits confer tolerance to desiccation and resistance to conventional disinfectants, raising concerns that standard hygiene and decontamination protocols may be inadequate to prevent transmission. Understanding these mechanisms is essential for designing effective infection control strategies and mitigating the risk of invasive disease caused by these highly persistent species. Full article

Peroxisomes are dynamic organelles involved in multiple metabolic pathways that respond to cellular and environmental conditions. Yeasts are a useful model for peroxisome studies, as their growth in media containing peroxisome proliferators, such as methanol, induces peroxisome biogenesis. We analyzed Ogataea polymorpha strains defective in peroxisome biogenesis (pex3Δ) or peroxisomal matrix protein import (pex6Δ). The mutant strains differed in their ability to survive dehydration and rehydration after incubation in peroxisome-inducing conditions, but these differences were not related to resistance to oxidative, hyperosmotic, or heat stress. These results indicate that peroxisomes support efficient entry into anhydrobiosis and subsequent recovery through a mechanism that is independent of general stress tolerance. We hypothesized that this effect is mediated by autophagic processes required for the removal of damaged organelles during desiccation. To test this hypothesis, we compared cells with basal peroxisome levels to cells with increased peroxisome numbers following the induction of peroxisome division. Autophagy was inhibited indirectly by disrupting vacuolar acidification with ammonium chloride. This strategy enabled us to explore how the peroxisome abundance and autophagic activity affect the ability of cells to enter anhydrobiosis and survive recovery. Full article

Extremotolerant fungi inhabit environments with multiple overlapping stressors, yet most studies examine stresses individually. We tested whether preconditioning with salt, cold, or both improves survival after desiccation and freezing, and whether combined salinity and temperature effects on growth are additive or synergistic. We studied Aureobasidium pullulans, Aureobasidium subglaciale, Aureobasidium melanogenum, and Hortaea werneckii (haploid and diploid). All preconditioning treatments significantly increased long-term desiccation survival in A. pullulans, reflecting its generalist capacity to activate cross-protective responses. H. werneckii displayed smaller improvements, consistent with a specialist strategy. Freezing survival without cryoprotectants remained ~100% in both species, indicating high intrinsic tolerance. Growth analyses revealed synergistic effects of salinity and temperature in Aureobasidium spp. Species differed in salinity sensitivity (A. melanogenum > A. pullulans > A. subglaciale) and thermal preferences. A. melanogenum and A. pullulans grew faster at higher temperatures, while A. subglaciale showed the opposite trend. In H. werneckii, salinity governed growth. Haploids slowed as salinity increased, while the diploid remained unaffected. This is the first confirmation of the long-standing suggestion that hybrid diploid genomes of many H. werneckii are an adaptation to osmotic stress. These findings illustrate two pathways to extremotolerance: inducible flexibility in Aureobasidium versus constitutive halotolerance in H. werneckii. Full article

As a monophyletic group, bryophytes—mosses, liverworts, and hornworts—represent some of the earliest land plants, evolving under harsh terrestrial conditions that prompted major morphological, physiological, and molecular changes. Limited water availability, extreme temperatures, and osmotic stresses often caused cellular desiccation in these pioneering plants. Because bryophytes occupy a key position in land-plant evolution and are closely related to streptophyte algae, their desiccation-tolerance strategies hold significant evolutionary importance. Early adaptations included changes in growth patterns and the formation of specialized vegetative structures. Bryophytes also survive extreme habitats by regulating physiological and biochemical traits such as photosynthetic pigment maintenance, osmotic adjustment, membrane stability, redox balance, and the accumulation of compatible solutes and stress-responsive proteins. Advances in molecular biology and whole-genome sequencing of model mosses and liverworts have further revealed that they possess diverse stress-responsive signaling components, including phytohormones, receptor proteins, protein kinases, and key transcription factors that control stress-related gene expression. However, a comprehensive synthesis of these molecular mechanisms is still lacking. This review aims to provide an updated overview of how mosses and liverworts use plant growth regulators, stress-responsive proteins, compatible solutes, antioxidants, and integrated signaling networks to survive in dry terrestrial environments. Full article

Seed storage is critical for preserving genetic resources, but optimal long-term storage conditions for Miscanthus seeds have not been established. In this five-year study, we evaluated storage protocols by comparing seed germination after four and five years, along with field establishment performance. The results demonstrated that genotype, storage conditions, and the storage duration all significantly influenced germination percentage and vigor index of Miscanthus seeds. Low temperature storage yielded the highest germination percentage (59.44%) and vigor index (132.06) in the 4th year, while low temperature with desiccant gave the highest germination percentage (42.41%) in the 5th year. The field performance after direct sowing was also significantly influenced by genotype and storage conditions, with the highest seedling survival (7.80%) observed under low temperature with desiccant. The seeds stored under low temperature exhibited minor structural damage, with the intact cell membranes, the small intercellular gaps, and the orderly cell arrangement. Through comprehensive evaluation, storage at −18 °C with desiccant was determined to be optimal. Based on these results, we strongly recommend storing Miscanthus seeds at −18 °C with desiccant. This protocol offers a reliable and effective solution for farmers, seed producers, and storage facilities to ensure long-term seed viability. Full article