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Ghezzi D, Salvi L, Costantini PE, Firrincieli A, Iorio M, Lopo E, Sosio M, Elbanna AH, Khalil ZG, Capon RJ, De Waele J, Vergara F, Sauro F, Cappelletti M. Ancient and remote quartzite caves as a novel source of culturable microbes with biotechnological potential. Microbiol Res 2024; 286:127793. [PMID: 38901277 DOI: 10.1016/j.micres.2024.127793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 05/23/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024]
Abstract
Quartzite caves located on table-top mountains (tepuis) in the Guyana Shield, are ancient, remote, and pristine subterranean environments where microbes have evolved peculiar metabolic strategies to thrive in silica-rich, slightly acidic and oligotrophic conditions. In this study, we explored the culturable fraction of the microbiota inhabiting the (ortho)quartzite cave systems in Venezuelan tepui (remote table-top mountains) and we investigated their metabolic and enzymatic activities in relation with silica solubilization and extracellular hydrolytic activities as well as the capacity to produce antimicrobial compounds. Eighty microbial strains were isolated with a range of different enzymatic capabilities. More than half of the isolated strains performed at least three enzymatic activities and four bacterial strains displayed antimicrobial activities. The antimicrobial producers Paraburkholderia bryophila CMB_CA002 and Sphingomonas sp. MEM_CA187, were further analyzed by conducting chemotaxonomy, phylogenomics, and phenomics. While the isolate MEM_CA187 represents a novel species of the genus Sphingomonas, for which the name Sphingomonas imawarii sp. nov. is proposed, P. bryophila CMB_CA002 is affiliated with a few strains of the same species that are antimicrobial producers. Chemical analyses demonstrated that CMB_CA002 produces ditropolonyl sulfide that has a broad range of activity and a possibly novel siderophore. Although the antimicrobial compounds produced by MEM_CA187 could not be identified through HPLC-MS analysis due to the absence of reference compounds, it represents the first soil-associated Sphingomonas strain with the capacity to produce antimicrobials. This work provides first insights into the metabolic potential present in quartzite cave systems pointing out that these environments are a novel and still understudied source of microbial strains with biotechnological potential.
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Affiliation(s)
- Daniele Ghezzi
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy
| | - Luca Salvi
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy
| | - Paolo E Costantini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy
| | - Andrea Firrincieli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy; Department for Innovation in Biological, Agro-Food and Forest systems, University of Tuscia, Viterbo 01100, Italy
| | | | - Ettore Lopo
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy
| | | | - Ahmed H Elbanna
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; Department of Pharmacognosy, Cairo University, Cairo 11562, Egypt
| | - Zeinab G Khalil
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert J Capon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jo De Waele
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna 40126, Italy; La Venta Geographic Explorations Association, Treviso 31100, Italy
| | - Freddy Vergara
- La Venta Geographic Explorations Association, Treviso 31100, Italy; Teraphosa Exploring Team, Puerto Ordaz, Venezuela
| | - Francesco Sauro
- La Venta Geographic Explorations Association, Treviso 31100, Italy
| | - Martina Cappelletti
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy; La Venta Geographic Explorations Association, Treviso 31100, Italy.
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Ghezzi D, Jiménez-Morillo NT, Foschi L, Donini E, Chiarini V, De Waele J, Miller AZ, Cappelletti M. The microbiota characterizing huge carbonatic moonmilk structures and its correlation with preserved organic matter. ENVIRONMENTAL MICROBIOME 2024; 19:25. [PMID: 38659019 PMCID: PMC11040949 DOI: 10.1186/s40793-024-00562-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 03/13/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Moonmilk represents complex secondary structures and model systems to investigate the interaction between microorganisms and carbonatic rocks. Grotta Nera is characterized by numerous moonmilk speleothems of exceptional size hanging from the ceiling, reaching over two meters in length. In this work we combined microbiological analyses with analytical pyrolysis and carbon stable isotope data to determine the molecular composition of these complex moonmilk structures as well as the composition of the associated microbiota. RESULTS Three moonmilk structures were dissected into the apical, lateral, and core parts, which shared similar values of microbial abundance, richness, and carbon isotopes but different water content, microbiota composition, and organic matter. Moonmilk parts/niches showed higher values of microbial biomass and biodiversity compared to the bedrock (not showing moonmilk development signs) and the waters (collected below dripping moonmilk), indicating the presence of more complex microbial communities linked to carbonate rock interactions and biomineralization processes. Although each moonmilk niche was characterized by a specific microbiota as well as a distinct organic carbon profile, statistical analyses clustered the samples in two main groups, one including the moonmilk lateral part and the bedrock and the other including the core and apical parts of the speleothem. The organic matter profile of both these groups showed two well-differentiated organic carbon groups, one from cave microbial activity and the other from the leaching of vascular plant litter above the cave. Correlation between organic matter composition and microbial taxa in the different moonmilk niches were found, linking the presence of condensed organic compounds in the apical part with the orders Nitrospirales and Nitrosopumilales, while different taxa were correlated with aromatic, lignin, and polysaccharides in the moonmilk core. These findings are in line with the metabolic potential of these microbial taxa suggesting how the molecular composition of the preserved organic matter drives the microbiota colonizing the different moonmilk niches. Furthermore, distinct bacterial and archaeal taxa known to be involved in the metabolism of inorganic nitrogen and C1 gases (CO2 and CH4) (Nitrospira, Nitrosopumilaceae, Nitrosomonadaceae, Nitrosococcaceae, and novel taxa of Methylomirabilota and Methanomassiliicoccales) were enriched in the core and apical parts of the moonmilk, probably in association with their contribution to biogeochemical cycles in Grotta Nera ecosystem and moonmilk development. CONCLUSIONS The moonmilk deposits can be divided into diverse niches following oxygen and water gradients, which are characterized by specific microbial taxa and organic matter composition originating from microbial activities or deriving from soil and vegetation above the cave. The metabolic capacities allowing the biodegradation of complex polymers from the vegetation above the cave and the use of inorganic nitrogen and atmospheric gases might have fueled the development of complex microbial communities that, by interacting with the carbonatic rock, led to the formation of these massive moonmilk speleothems in Grotta Nera.
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Affiliation(s)
- Daniele Ghezzi
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, Bologna, 40126, Italy
| | - Nicasio Tomás Jiménez-Morillo
- MED-Mediterranean Institute for Agriculture, Environment and Development, University of Évora, Pólo da Mitra Apartado 94, Évora, 7006-554, Portugal
- Instituto de Recursos Naturales y Agrobiologia de Sevilla (IRNAS-CSIC), Av. de la Reina Mercedes, 10, Sevilla, 41012, Spain
| | - Lisa Foschi
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, Bologna, 40126, Italy
| | - Eva Donini
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, Bologna, 40126, Italy
| | - Veronica Chiarini
- Department of Geosciences, University of Padova, via Gradenigo 6, Padua, 35131, Italy
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Via Zamboni 67, Bologna, 40126, Italy
| | - Jo De Waele
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Via Zamboni 67, Bologna, 40126, Italy
| | - Ana Zélia Miller
- Instituto de Recursos Naturales y Agrobiologia de Sevilla (IRNAS-CSIC), Av. de la Reina Mercedes, 10, Sevilla, 41012, Spain.
- HERCULES Laboratory, University of Évora, Largo dos Colegiais 2, Évora, 7004-516, Portugal.
| | - Martina Cappelletti
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, Bologna, 40126, Italy.
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Turrini P, Chebbi A, Riggio FP, Visca P. The geomicrobiology of limestone, sulfuric acid speleogenetic, and volcanic caves: basic concepts and future perspectives. Front Microbiol 2024; 15:1370520. [PMID: 38572233 PMCID: PMC10987966 DOI: 10.3389/fmicb.2024.1370520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/07/2024] [Indexed: 04/05/2024] Open
Abstract
Caves are ubiquitous subterranean voids, accounting for a still largely unexplored surface of the Earth underground. Due to the absence of sunlight and physical segregation, caves are naturally colonized by microorganisms that have developed distinctive capabilities to thrive under extreme conditions of darkness and oligotrophy. Here, the microbiomes colonizing three frequently studied cave types, i.e., limestone, sulfuric acid speleogenetic (SAS), and lava tubes among volcanic caves, have comparatively been reviewed. Geological configurations, nutrient availability, and energy flows in caves are key ecological drivers shaping cave microbiomes through photic, twilight, transient, and deep cave zones. Chemoheterotrophic microbial communities, whose sustenance depends on nutrients supplied from outside, are prevalent in limestone and volcanic caves, while elevated inorganic chemical energy is available in SAS caves, enabling primary production through chemolithoautotrophy. The 16S rRNA-based metataxonomic profiles of cave microbiomes were retrieved from previous studies employing the Illumina platform for sequencing the prokaryotic V3-V4 hypervariable region to compare the microbial community structures from different cave systems and environmental samples. Limestone caves and lava tubes are colonized by largely overlapping bacterial phyla, with the prevalence of Pseudomonadota and Actinomycetota, whereas the co-dominance of Pseudomonadota and Campylobacterota members characterizes SAS caves. Most of the metataxonomic profiling data have so far been collected from the twilight and transient zones, while deep cave zones remain elusive, deserving further exploration. Integrative approaches for future geomicrobiology studies are suggested to gain comprehensive insights into the different cave types and zones. This review also poses novel research questions for unveiling the metabolic and genomic capabilities of cave microorganisms, paving the way for their potential biotechnological applications.
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Affiliation(s)
- Paolo Turrini
- Department of Science, Roma Tre University, Rome, Italy
| | - Alif Chebbi
- Department of Science, Roma Tre University, Rome, Italy
| | | | - Paolo Visca
- Department of Science, Roma Tre University, Rome, Italy
- National Biodiversity Future Center, Palermo, Italy
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Pop MM, Di Lorenzo T, Iepure S. Living on the edge – An overview of invertebrates from groundwater habitats prone to extreme environmental conditions. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2022.1054841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Groundwater ecosystems from cold polar and circumpolar regions, hot springs, as well as those developed in salt, gypsum or in volcanic rocks are one of the environments considered to exhibit extreme environmental conditions such as low (below 0°C) or high (over 45°C) temperatures, hypersaline waters, or with elevated content of toxic gases like hydrogen sulfide or methane. They represent the “unseen ecosystem beneath our feet” and are inhabited by a large diversity of organisms, persisting and flourishing under severe environmental conditions that are usually hostile to the majority of organisms. These types of groundwater ecosystems are remarkable “evolutionary hotspots” that witnessed the adaptive radiation of morphologically and ecologically diverse species, whereas the organisms living here are good models to understand the evolutionary processes and historical factors involved in speciation and adaptation to severe environmental conditions. Here, we provide an overview of the groundwater invertebrates living in continental groundwater habitats prone to extreme environmental conditions in one or more physico-chemical parameters. Invertebrates are represented by a wide variety of taxonomic groups, however dominated by crustaceans that show specific adaptations mostly metabolic, physiologic, and behavioral. Symbiotic associations among bacteria and invertebrates are also discussed enlightening this biological interaction as a potential adaptation of different groundwater invertebrates to cope with severe environmental conditions. Given the high pressures that anthropogenic activities pose on groundwater habitats worldwide, we predict that several of these highly specialized organisms will be prone to extinction in the near future. Finally, we highlight the knowledge gaps and future research approaches in these particular groundwater ecosystems by using integrative-omic studies besides the molecular approach to shed light on genetic variation and phenotypic plasticity at species and populational levels.GRAPHICAL ABSTRACT
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Horn EJ, van Hille RP, Oyekola OO, Welz PJ. Functional Microbial Communities in Hybrid Linear Flow Channel Reactors for Desulfurization of Tannery Effluent. Microorganisms 2022; 10:2305. [PMID: 36422375 PMCID: PMC9695182 DOI: 10.3390/microorganisms10112305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2024] Open
Abstract
Recent research has demonstrated that hybrid linear flow channel reactors (HLFCRs) can desulfurize tannery effluent via sulfate reduction and concurrent oxidation of sulfide to elemental sulfur. The reactors can be used to pre-treat tannery effluent to improve the efficiency of downstream anaerobic digestion and recover sulfur. This study was conducted to gain insight into the bacterial communities in HLFCRs operated in series and identify structure-function relationships. This was accomplished by interpreting the results obtained from amplicon sequencing of the 16S rRNA gene and quantification of the dissimilatory sulfite reducing (dsrB) gene. In an effort to provide a suitable inoculum, microbial consortia were harvested from saline estuaries and enriched. However, it was found that bioaugmentation was not necessary because native communities from tannery wastewater were selected over exogenous communities from the enriched consortia. Overall, Dethiosulfovibrio sp. and Petrimonas sp. were strongly selected (maximum relative abundances of 29% and 26%, respectively), while Desulfobacterium autotrophicum (57%), and Desulfobacter halotolerans (27%) dominated the sulfate reducing bacteria. The presence of elemental sulfur reducing genera such as Dethiosulfovibrio and Petrimonas is not desirable in HLFCRs, and strategies to counter their selection need to be considered to ensure efficiency of these systems for pre-treatment of tannery effluent.
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Chiciudean I, Russo G, Bogdan DF, Levei EA, Faur L, Hillebrand-Voiculescu A, Moldovan OT, Banciu HL. Competition-cooperation in the chemoautotrophic ecosystem of Movile Cave: first metagenomic approach on sediments. ENVIRONMENTAL MICROBIOME 2022; 17:44. [PMID: 35978381 PMCID: PMC9386943 DOI: 10.1186/s40793-022-00438-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/05/2022] [Indexed: 05/30/2023]
Abstract
BACKGROUND Movile Cave (SE Romania) is a chemoautotrophically-based ecosystem fed by hydrogen sulfide-rich groundwater serving as a primary energy source analogous to the deep-sea hydrothermal ecosystems. Our current understanding of Movile Cave microbiology has been confined to the sulfidic water and its proximity, as most studies focused on the water-floating microbial mat and planktonic accumulations likely acting as the primary production powerhouse of this unique subterranean ecosystem. By employing comprehensive genomic-resolved metagenomics, we questioned the spatial variation, chemoautotrophic abilities, ecological interactions and trophic roles of Movile Cave's microbiome thriving beyond the sulfidic-rich water. RESULTS A customized bioinformatics pipeline led to the recovery of 106 high-quality metagenome-assembled genomes from 7 cave sediment metagenomes. Assemblies' taxonomy spanned 19 bacterial and three archaeal phyla with Acidobacteriota, Chloroflexota, Proteobacteria, Planctomycetota, Ca. Patescibacteria, Thermoproteota, Methylomirabilota, and Ca. Zixibacteria as prevalent phyla. Functional gene analyses predicted the presence of CO2 fixation, methanotrophy, sulfur and ammonia oxidation in the explored sediments. Species Metabolic Coupling Analysis of metagenome-scale metabolic models revealed the highest competition-cooperation interactions in the sediments collected away from the water. Simulated metabolic interactions indicated autotrophs and methanotrophs as major donors of metabolites in the sediment communities. Cross-feeding dependencies were assumed only towards 'currency' molecules and inorganic compounds (O2, PO43-, H+, Fe2+, Cu2+) in the water proximity sediment, whereas hydrogen sulfide and methanol were assumedly traded exclusively among distant gallery communities. CONCLUSIONS These findings suggest that the primary production potential of Movile Cave expands way beyond its hydrothermal waters, enhancing our understanding of the functioning and ecological interactions within chemolithoautotrophically-based subterranean ecosystems.
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Affiliation(s)
- Iulia Chiciudean
- Department of Molecular Biology and Biotechnology, Babeș-Bolyai University, Cluj-Napoca, Romania
| | - Giancarlo Russo
- EMBL Partner Institute for Genome Editing, Life Sciences Center–Vilnius University, Vilnius, Lithuania
| | - Diana Felicia Bogdan
- Department of Molecular Biology and Biotechnology, Babeș-Bolyai University, Cluj-Napoca, Romania
- Doctoral School of Integrative Biology, Babeș-Bolyai University, Cluj-Napoca, Romania
| | - Erika Andrea Levei
- National Institute for Research and Development for Optoelectronics, Research Institute for Analytical Instrumentation Subsidiary, Cluj-Napoca, Romania
| | - Luchiana Faur
- Emil Racovita Institute of Speleology, Geospeleology and Paleontology Department, Bucharest, Romania
- Romanian Institute of Science and Technology, Cluj-Napoca, Romania
| | - Alexandra Hillebrand-Voiculescu
- Romanian Institute of Science and Technology, Cluj-Napoca, Romania
- Biospeology and Edaphobiology Department, Emil Racovita Institute of Speleology, Bucharest, Romania
| | - Oana Teodora Moldovan
- Romanian Institute of Science and Technology, Cluj-Napoca, Romania
- Cluj-Napoca Department, Emil Racovita Institute of Speleology, Cluj-Napoca, Romania
| | - Horia Leonard Banciu
- Department of Molecular Biology and Biotechnology, Babeș-Bolyai University, Cluj-Napoca, Romania
- Centre for Systems Biology, Biodiversity and Bioresources, Babeș-Bolyai University, Cluj-Napoca, Romania
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