Search Results (30)

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

The evolution of robust DNA repair mechanisms was a prerequisite for the conquest of land by plants, a transition that exposed them to harsh new environmental stressors. The poly (ADP-ribose) polymerase (PARP) family is central to this adaptation, as it orchestrates DNA repair and stress signaling pathways essential for coping with the elevated UV radiation and desiccation of terrestrial environments. Yet its early evolutionary origins are unknown. Here, we present a comprehensive reconstruction of the PARP family’s history across the plant kingdom. Our phylogenomic analysis reveals that PARP evolution ignited during the bryophyte radiation, expanding from a single ancestral algal gene into three distinct subfamilies (PARP1, PARP2, and PARP3). This diversification was driven by structural innovations in DNA-binding domains and a rewiring of transcriptional networks to respond to terrestrial challenges. We provide direct experimental support for this hypothesis through functional analysis of PARPs from the extremotolerant moss Syntrichia caninervis. We show that its PARP proteins provide multifaceted protection against UV radiation, heat, and genotoxic agents, and that recently duplicated PARP2 genes are already diverging in function. Our work pinpoints the molecular adaptations in a key DNA repair family that enabled the greening of Earth and uncovers novel genetic targets for enhancing crop resilience. Full article

Extreme environments are a largely unexplored reservoir of microbial diversity, with a remarkable potential to be exploited in agriculture. One hundred and seventeen yeast isolates, derived from different ecosystems in Italy, Sweden, Algeria, and France, were molecularly identified, and the most represented genus was Aureobasidium (57%). A phylogenetic analysis based on a multi-locus sequence typing (ITS, ELO, EF-1alpha) was conducted to characterize the black yeasts’ population. To investigate A. pullulans extremophilic and extremotolerant behaviour, different temperatures and pH, together with the enzymatic production, were evaluated. The strains were tested by in vitro and in vivo assays against the postharvest fungal pathogen Monilinia fructicola as potential biocontrol agents (BCAs). Results displayed a great ecological variability concerning strains’ growth and cell production depending on different culture conditions. However, a remarkable thermotolerance aptitude was detected in almost all the strains. In particular, the strains belonging to Group 2 (Algerian Desert) and 3 (Alto Adige Region) showed, respectively, higher thermotolerance and biocontrol ability. These findings showed how some extreme environments could represent a promising source for new potential BCAs. However, further studies are needed to investigate the mechanisms of action of these putative BCAs for application during the postharvest phase. Full article

Common bean (Phaseolus vulgaris L.) is a critical protein-rich legume supporting food and nutritional security globally. However, Fusarium wilt, caused by Fusarium solani, remains a major constraint to production, with yield losses reaching up to 84%. While biocontrol strategies have been explored, most microbial agents are sourced from mesophilic environments and show limited effectiveness under abiotic stress. Here, we report the isolation and characterization of extremophilic Bacillus spp. from the hypersaline Lake Bogoria, Kenya, and their biocontrol potential against F. solani. From 30 isolates obtained via serial dilution, 9 exhibited antagonistic activity in vitro, with mycelial inhibition ranging from 1.07–1.93 cm 16S rRNA sequencing revealed taxonomic diversity within the Bacillus genus, including unique extremotolerant strains. Molecular screening identified genes associated with the biosynthesis of antifungal metabolites such as 2,4-diacetylphloroglucinol, pyrrolnitrin, and hydrogen cyanide. Enzyme assays confirmed substantial production of chitinase (1.33–3160 U/mL) and chitosanase (10.62–28.33 mm), supporting a cell wall-targeted antagonism mechanism. In planta assays with the lead isolate (B7) significantly reduced disease incidence (8–35%) and wilt severity (1–5 affected plants), while enhancing root colonization under pathogen pressure. These findings demonstrate that extremophile-derived Bacillus spp. possess robust antifungal traits and highlight their potential as climate-resilient biocontrol agents for sustainable bean production in arid and semi-arid agroecosystems. Full article

Extremophilic microorganisms offer an untapped potential for producing unique bioactive metabolites with therapeutic applications. In the current study, bacterial isolates were obtained from samples collected from Chamalang cave located in Kohlu District, Balochistan, Pakistan. The cave-derived isolate C1 (Rhodococcus jialingiae) exhibits prominent antibacterial activity against multidrug-resistant pathogens (MDR), including Escherichia coli, Staphylococcus aureus, and Micrococcus luteus. It also demonstrates substantial antioxidant activity, with 71% and 58.39% DPPH radical scavenging. Optimization of physicochemical conditions, such as media, pH, temperature, and nitrogen and carbon sources and concentrations substantially enhanced both biomass and metabolite yields. Optimal conditions comprise specialized media, a pH of 7, a temperature of 30 °C, peptone (1.0 g/L) as the nitrogen source, and glucose (0.5 g/L) as the carbon source. HPLC and QTOF-MS analyses uncovered numerous metabolites, including a phenolic compound, 2-[(E)-3-hydroxy-3-(4-methoxyphenyl) prop-2-enoyl]-4-methoxyphenolate, Streptolactam C, Puromycin, and a putative aromatic polyketide highlighting the C1 isolate chemical. Remarkably, one compound (C₁₄H₃₆N₇) demonstrated a special molecular profile, signifying structural novelty and warranting further characterization by techniques such as ¹H and ¹³C NMR. These findings highlight the biotechnological capacity of the C1 isolate as a source of novel antimicrobials and antioxidants, linking environmental adaptation to metabolic potential and supporting natural product discovery pipelines against antibiotic resistance. Full article

Often thought of as a mesic paradise, forest ecosystems are a mosaic of microhabitats with temporal oscillations that cause significant environmental stresses, providing habitats for extremophilic and extremotolerant fungi. Adapted to survive and thrive under conditions lethal to most mesophiles (e.g., extreme temperatures, pH, water potential, radiation, salinity, nutrient scarcity, and pollutants), these species are increasingly recognized as vital yet underappreciated elements of forest biodiversity and function. This review examines the current understanding of the roles of extremophilic fungi in forests, scrutinizing their presence in these ecosystems with a critical eye. Particularly under severe environmental conditions, extremophilic fungi play a crucial role in forest ecosystems, as they significantly enhance decomposition and nutrient cycling, and foster mutualistic interactions with plants that increase stress resilience. This helps to maintain ecosystem stability. We examine the definition of “extreme” within forest settings, survey the known diversity and distribution of these fungi across various forest stress niches (cold climates, fire-affected areas, acidic soils, canopy surfaces, polluted sites), and delve into their possible ecological functions, including decomposition of recalcitrant matter, nutrient cycling under stress, interactions with plants (pathogenesis, endophytism, perhaps mycorrhizae), bioremediation, and contributions to soil formation. However, the review stresses significant methodological difficulties, information gaps, and field-based natural biases. We recommend overcoming cultural constraints, enhancing the functional annotation of “omics” data, and planning investigations that clarify the specific activities and interactions of these cryptic creatures within the forest matrix to further advance the field. Here, we demonstrate that moving beyond simple identification to a deeper understanding of function will enable us to more fully appreciate the value of extremophilic fungi in forest ecosystems, particularly in relation to environmental disturbances and climate change. Full article

Cyanobacteria isolated from extreme habitats are promising in biotechnology due to their high adaptability to unfavorable environments and their specific natural products. Therefore, these organisms are stored under a reduced light supply in multiple collections worldwide. However, it remains unclear whether these strains maintain constitutively expressed primary metabolome features associated with their unique adaptations. To address this question, a comparative analysis of primary metabolomes of twelve cyanobacterial strains from diverse extreme habitats was performed by a combined GC-MS/LC-MS approach. The results revealed that all these cyanobacterial strains exhibited clear differences in their patterns of primary metabolites. These metabolic differences were more pronounced for the strains originating from ecologically different extreme environments. Extremotolerant terrestrial and freshwater strains contained lower strain-specifically accumulated primary metabolites than extremophilic species from habitats with high salinity and alkalinity. The latter group of strains was highly diverse in amounts of specific primary metabolites. This might indicate essentially different molecular mechanisms and metabolic pathways behind the survival of the microorganisms in saline and alkaline environments. The identified strain-specific metabolites are discussed with respect to the metabolic processes that might impact maintaining the viability of cyanobacteria during their storage and indicate unique adaptations formed in their original extreme habitats. Full article

Biocatalysis is a green and sustainable technology based on the use of natural substances to catalyze chemical reactions. Humans have been unconsciously using biocatalysis for thousands of years to produce food and alcoholic beverages, but it is only since the 19th century that we have begun to understand its fundamentals and its enormous potential. In fact, advances in our knowledge of enzymes and metabolic pathways and, in recent decades, the introduction of tools such as bioinformatics, DNA sequencing and protein engineering have made biocatalysis a key strategy in fine chemistry and for the production of active pharmaceutical ingredients. In addition, the discovery of new microorganisms adapted to adverse conditions has also been crucial in advancing this avenue. The present review focuses on the use of unconventional yeasts and their enzymes in the most interesting reactions where biocatalysis is applied. It highlights the advantages of using these microorganisms in industrial chemical processes due to their particular phenotypes, such as their ability to withstand high temperatures and pressures, as well as acidic or alkaline environments, high substrate loads, presence of organic solvents, etc. All this results in a wider range of possible substrates and higher efficiency. Examples of the most important reactions in which their use has been described are included, considering both catalysis by wild-type whole cells or their isolated enzymes and their genetically modified variants. All this information will help to understand the current relevance of unconventional yeasts and their enzymes in biocatalysis. Full article

The respiratory activities of mitochondrial complexes I, II, and IV were analyzed in permeabilized Rhodotorula mucilaginosa cells and isolated mitochondria, and the kinetic parameters K_0.5 and V_max were obtained. No difference in substrate affinities were found between mitochondria and permeabilized cells. The activities of the components of the mitochondrial respiratory chain of the Antarctic yeast R. mucilaginosa M94C9 were identified by in-gel activity and SDS-PAGE. The mitochondria exhibited activity for the classical components of the electron transport chain (Complexes I, II, III, and IV), and supercomplexes were formed by a combination of the respiratory complexes I, III, and IV. Unfortunately, the activities of the monomeric and dimeric forms of the F1F0-ATP synthase were not revealed by the in-gel assay, but the two forms of the ATP synthase were visualized in the SDS-PAGE. Furthermore, two alternative pathways for the oxidation of cytosolic NADH were identified: the alternative NADH dehydrogenase and the glycerol-3-phosphate dehydrogenase. In addition, an NADPH dehydrogenase and a lactate cytochrome b2 dehydrogenase were found. The residual respiratory activity following cyanide addition suggests the presence of an alternative oxidase in cells. Full article

Exploring extremotolerant and extremophilic microalgae opens new frontiers in sustainable biotechnological applications. These microorganisms thrive in extreme environments and exhibit specialized metabolic pathways, making them valuable for various industries. The study focuses on the ecological adaptation and biotechnological potential of these microalgae, highlighting their ability to produce bioactive compounds under stress conditions. The literature reveals that extremophilic microalgae can significantly enhance biomass production, reduce contamination risks in large-scale systems, and produce valuable biomolecules such as carotenoids, lipids, and proteins. These insights suggest that extremophilic microalgae have promising applications in food, pharmaceutical, cosmetic, and biofuel industries, offering sustainable and efficient alternatives to traditional resources. The review concludes that further exploration and utilization of these unique microorganisms can lead to innovative and environmentally friendly solutions in biotechnology. Full article

Wooden Cultural Heritage (WCH) represents a significant portion of the world’s historical and artistic heritage, consisting of immovable and movable artefacts. Despite the expertise developed since ancient times to enhance its durability, wooden artefacts are inevitably prone to degradation. Fungi play a pivotal role in the deterioration of WCH in terrestrial ecosystems, accelerating its decay and leading to alterations in color and strength. Reviewing the literature of the last 25 years, we aimed to provide a comprehensive overview of fungal diversity affecting WCH, the biochemical processes involved in wood decay, and the diagnostic tools available for fungal identification and damage evaluation. Climatic conditions influence the occurrence of fungal species in threatened WCH, characterized by a prevalence of wood-rot fungi (e.g., Serpula lacrymans, Coniophora puteana) in architectural heritage in temperate and continental climates and Ascomycota in indoor and harsh environments. More efforts are needed to address the knowledge fragmentation concerning biodiversity, the biology of the fungi involved, and succession in the degradative process, which is frequently centered solely on the main actors. Multidisciplinary collaboration among engineers, restorers, and life sciences scientists is vital for tackling the challenges posed by climate change with increased awareness. Traditional microbiology and culture collections are fundamental in laying solid foundations for a more comprehensive interpretation of big data. Full article

Saxispiralis lemnorum MUM 23.14 is an extremotolerant microcolonial black fungus, originally isolated from a biodeteriorated limestone artwork in Portugal. This recently introduced species belongs to the Aeminiaceae family, representing the second member of this monophyletic clade. This fungus exhibits a unique set of characteristics, including xerophily, cold tolerance, high UV radiation tolerance, and an exceptional ability to thrive in NaCl concentrations of up to 30% while also enduring pH levels ranging from 5 to 11. To gain insights into its genomic traits associated with stress resistance mechanisms, specialization, and their potential implications in stone biodeterioration, we conducted a comprehensive genome sequencing and analysis. This draft genome not only marks the first for the Saxispiralis genus but also the second for the Aeminiaceae family. Furthermore, we performed two comparative genomic analyses: one focusing on the closest relative within the Aeminiaceae family, Aeminium ludgeri, and another encompassing the genome of different extremotolerant black fungi. In this study, we successfully achieved high genome completeness for S. lemnorum and confirmed its close phylogenetic relationship to A. ludgeri. Our findings revealed traits contributing to its extremophilic nature and provided insights into potential mechanisms contributing to stone biodeterioration. Many traits are common to both Aeminiaceae species and are shared with other black fungi, while numerous unique traits may be attributed to species-specific characteristics. Full article

Tardigrades, with over 1450 species, are important organisms in ecological understanding and are valuable biological models (e.g., due to their extremotolerant capabilities). While their biodiversity is better known in Europe and North America, Central and South America have only recently started making significant contributions. Through a comprehensive review of scientific literature, biological collections, web portal consultations, and the addition of new records, this study clarifies the current knowledge of tardigrade biodiversity in Colombia. Past research started in the early 20th century, but most data are unreliable due to information gaps and the absence of specimens in biological collections. The last decade has witnessed a resurgence in tardigrade research in Colombia, leading to new species descriptions and a more robust understanding of their biodiversity. Nevertheless, the majority of the territory remains unexplored. A total of 43 known species from our analysis are present in Colombia: 26 records accepted by the literature and 17 questioned in the literature but representing distinct taxa surely present in Colombia. Other species records are considered doubtful. Our study recommends considering mostly scientific records based on verifiable material deposited in scientific collections (highlighting their importance in studying and safeguarding biodiversity) and encourages future researchers to contribute while adhering to legal requirements. Full article

Sustainable mechanisms for efficient and circular metal recycling have yet to be uncovered. In this study, the metal recycling potential of seven metal-resistant bacterial species (Deinococcus radiodurans, Deinococcus aerius, Bacillus coagulans, Pseudomonas putida, Staphylococcus rimosus, Streptomyces xylosus and Acidocella aluminiidurans) was investigated in a multi-step strategy, which comprises bioleaching of industrial waste products and subsequent biosorption/bioaccumulation studies. Each species was subjected to an acidic, multi-metal bioleachate solution and screened for potential experimental implementation. Bacterial growth and metal acquisition were examined using scanning transmission electron microscopy coupled to electron dispersive X-ray spectroscopy (STEM-EDS). Two of the seven screened species, D. aerius and A. aluminiidurans, propagated in a highly acidic and metal-laden environment. Both accumulated iron and copper compounds during cultivation on a multi-metallic bioleachate. Our findings suggest that extremotolerant bacteria should be considered for waste recycling operations due to their inherent polyextremophily. Furthermore, STEM-EDS is a promising tool to investigate microbial–metal interactions in the frames of native industrial waste products. To develop further experimental steps, detailed analyses of adsorption/accumulation mechanisms in D. aerius and A. aluminiidurans are required to design a circular metal recycling procedure. Full article

Fungi are the most diverse living organisms on planet Earth, where their ubiquitous presence in various ecosystems offers vast potential for the research and discovery of new, naturally occurring medicinal products. Concerning human health, cancer remains one of the leading causes of mortality. While extensive research is being conducted on treatments and their efficacy in various stages of cancer, finding cytotoxic drugs that target tumor cells with no/less toxicity toward normal tissue is a significant challenge. In addition, traditional cancer treatments continue to suffer from chemical resistance. Fortunately, the cytotoxic properties of several natural products derived from various microorganisms, including fungi, are now well-established. The current review aims to extract and consolidate the findings of various scientific studies that identified fungi-derived bioactive metabolites with antitumor (anticancer) properties. The antitumor secondary metabolites identified from extremophilic and extremotolerant fungi are grouped according to their biological activity and type. It became evident that the significance of these compounds, with their medicinal properties and their potential application in cancer treatment, is tremendous. Furthermore, the utilization of omics tools, analysis, and genome mining technology to identify the novel metabolites for targeted treatments is discussed. Through this review, we tried to accentuate the invaluable importance of fungi grown in extreme environments and the necessity of innovative research in discovering naturally occurring bioactive compounds for the development of novel cancer treatments. Full article