scholarly journals Metagenomic Insights Into the Microbial Communities of Inert and Oligotrophic Outdoor Pier Surfaces of a Coastal City

2021 ◽  
Author(s):  
Xinzhao Tong ◽  
Marcus H. Y. Leung ◽  
Zhiyong Shen ◽  
Justin Y. Y. Lee ◽  
Christopher E. Mason ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Taxonomic Composition ◽  
Metagenomic Sequencing ◽  
Biosynthetic Gene Clusters ◽  
Metabolic Functions ◽  
Outdoor Spaces ◽  
Genomic Characterization ◽  
Indoor Spaces

Abstract Background: Studies of the microbiomes on surfaces in built environment have largely focused on indoor spaces, while outdoor spaces have received far less attention. Piers are engineered infrastructures commonly found in coastal areas, and due to their unique locations at the interface between terrestrial and aquatic ecosystems, pier surfaces are likely to harbor interesting microbiology. In this study, the microbiomes on the metal and concrete surfaces at nine piers located along the coastline of Hong Kong were investigated by metagenomic sequencing. The roles played by different factors in shaping the taxonomic composition and functional traits of the pier surface microbiomes were determined. Metagenome-assembled genomes were reconstructed and their putative biosynthetic gene clusters were characterized in detail.Results: Surface material was found to be the strongest factor in structuring the taxonomic and functional compositions of the pier surface microbiomes. Corrosion-related bacteria were significantly enriched on metal surfaces, consistent with the pitting corrosion observed. The differential enrichment of taxa mediating biodegradation suggests differences between the metal and concrete surfaces in terms of specific xenobiotics being potentially degraded. Genome-centric analysis detected the presence of many novel species, with the majority of them belonging to the phylum Proteobacteria. Genomic characterization showed that the potential metabolic functions and secondary biosynthetic capacity were largely governed by taxonomy, rather than surface attributes and geography. Conclusions: Pier surfaces are a rich reservoir of abundant novel bacterial species. Members of the surface microbial communities use different mechanisms to counter the stresses under oligotrophic conditions. A better understanding of the outdoor surface microbiomes located in different environments should enhance the ability to maintain outdoor surfaces of infrastructures.

scholarly journals Metagenomic insights into the microbial communities of inert and oligotrophic outdoor pier surfaces of a coastal city

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xinzhao Tong ◽  
Marcus H. Y. Leung ◽  
Zhiyong Shen ◽  
Justin Y. Y. Lee ◽  
Christopher E. Mason ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Taxonomic Composition ◽  
Metagenomic Sequencing ◽  
Metabolic Functions ◽  
Outdoor Spaces ◽  
Physical Attributes ◽  
Genomic Characterization ◽  
Indoor Spaces

Abstract Background Studies of the microbiomes on surfaces in built environment have largely focused on indoor spaces, while outdoor spaces have received far less attention. Piers are engineered infrastructures commonly found in coastal areas, and due to their unique locations at the interface between terrestrial and aquatic ecosystems, pier surfaces are likely to harbor interesting microbiology. In this study, the microbiomes on the metal and concrete surfaces at nine piers located along the coastline of Hong Kong were investigated by metagenomic sequencing. The roles played by different physical attributes and environmental factors in shaping the taxonomic composition and functional traits of the pier surface microbiomes were determined. Metagenome-assembled genomes were reconstructed and their putative biosynthetic gene clusters were characterized in detail. Results Surface material was found to be the strongest factor in structuring the taxonomic and functional compositions of the pier surface microbiomes. Corrosion-related bacteria were significantly enriched on metal surfaces, consistent with the pitting corrosion observed. The differential enrichment of taxa mediating biodegradation suggests differences between the metal and concrete surfaces in terms of specific xenobiotics being potentially degraded. Genome-centric analysis detected the presence of many novel species, with the majority of them belonging to the phylum Proteobacteria. Genomic characterization showed that the potential metabolic functions and secondary biosynthetic capacity were largely correlated with taxonomy, rather than surface attributes and geography. Conclusions Pier surfaces are a rich reservoir of abundant novel bacterial species. Members of the surface microbial communities use different mechanisms to counter the stresses under oligotrophic conditions. A better understanding of the outdoor surface microbiomes located in different environments should enhance the ability to maintain outdoor surfaces of infrastructures.

scholarly journals Salicylic Acid Biosynthesis and Metabolism: A Divergent Pathway for Plants and Bacteria

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 705
Author(s):  
Awdhesh Kumar Mishra ◽  
Kwang-Hyun Baek
Keyword(s):  
Salicylic Acid ◽  
Bacterial Species ◽  
Shikimate Pathway ◽  
Gene Clusters ◽  
Defense Responses ◽  
Biosynthetic Gene ◽  
Biosynthetic Enzyme ◽  
Biosynthetic Gene Clusters ◽  
Acid Biosynthesis ◽  
Common Precursor

Salicylic acid (SA) is an active secondary metabolite that occurs in bacteria, fungi, and plants. SA and its derivatives (collectively called salicylates) are synthesized from chorismate (derived from shikimate pathway). SA is considered an important phytohormone that regulates various aspects of plant growth, environmental stress, and defense responses against pathogens. Besides plants, a large number of bacterial species, such as Pseudomonas, Bacillus, Azospirillum, Salmonella, Achromobacter, Vibrio, Yersinia, and Mycobacteria, have been reported to synthesize salicylates through the NRPS/PKS biosynthetic gene clusters. This bacterial salicylate production is often linked to the biosynthesis of small ferric-ion-chelating molecules, salicyl-derived siderophores (known as catecholate) under iron-limited conditions. Although bacteria possess entirely different biosynthetic pathways from plants, they share one common biosynthetic enzyme, isochorismate synthase, which converts chorismate to isochorismate, a common precursor for synthesizing SA. Additionally, SA in plants and bacteria can undergo several modifications to carry out their specific functions. In this review, we will systematically focus on the plant and bacterial salicylate biosynthesis and its metabolism.

scholarly journals Microbial characterisation and Cold-Adapted Predicted Protein (CAPP) database construction from the active layer of Greenland's permafrost

2021 ◽  
Author(s):  
Gilda Varliero ◽  
Muhammad Rafiq ◽  
Swati Singh ◽  
Annabel Summerfield ◽  
Fotis Sgouridis ◽  
...  
Keyword(s):  
Active Layer ◽  
Sequence Variation ◽  
Gene Clusters ◽  
Taxonomic Composition ◽  
Sequence Information ◽  
Biosynthetic Gene Clusters ◽  
Medical Settings ◽  
Cold Adapted ◽  
Database Construction ◽  
Medium Quality

Abstract Permafrost represents a reservoir for the biodiscovery of cold-adapted proteins which are advantageous in industrial and medical settings. Comparisons between different thermo-adapted proteins can give important information for cold-adaptation bioengineering. We collected permafrost active layer samples from 34 points along a proglacial transect in southwest Greenland. We obtained a deep read coverage assembly (>164x) from nanopore and Illumina sequences for the purposes of i) analysing metagenomic and metatranscriptomic trends of the microbial community of this area, and ii) creating the Cold-Adapted Predicted Protein (CAPP) database. The community showed a similar taxonomic composition in all samples along the transect, with a solid permafrost-shaped community, rather than microbial trends typical of proglacial systems. We retrieved 69 high- and medium-quality metagenome-assembled clusters, 213 complete biosynthetic gene clusters and more than three million predicted proteins. The latter constitute the CAPP database that can provide cold-adapted protein sequence information for protein- and taxon-focused amino acid sequence modifications for the future bioengineering of cold-adapted enzymes. As an example, we focused on the enzyme polyphenol oxidase, and demonstrated how sequence variation information could inform its protein engineering.

scholarly journals Metagenomic exploration of the marine sponge mycale hentscheli uncovers multiple polyketide-producing bacterial symbionts

2020 ◽  
Author(s):  
Mathew Storey ◽  
SK Andreassend ◽  
Joe Bracegirdle ◽  
Alistair Brown ◽  
Robert Keyzers ◽  
...  
Keyword(s):  
Marine Sponge ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Taxonomic Diversity ◽  
Marine Sponges ◽  
Metagenomic Sequencing ◽  
Defensive Symbiosis ◽  
Long Read ◽  
Comprehensive Picture ◽  
Mycale Hentscheli

© 2020 Storey et al. Marine sponges have been a prolific source of unique bioactive compounds that are presumed to act as a deterrent to predation. Many of these compounds have potential therapeutic applications; however, the lack of efficient and sustainable synthetic routes frequently limits clinical development. Here, we describe a metag-enomic investigation of Mycale hentscheli, a chemically gifted marine sponge that pos-sesses multiple distinct chemotypes. We applied shotgun metagenomic sequencing, hybrid assembly of short-and long-read data, and metagenomic binning to obtain a comprehensive picture of the microbiome of five specimens, spanning three chemo-types. Our data revealed multiple producing species, each having relatively modest secondary metabolomes, that contribute collectively to the chemical arsenal of the holo-biont. We assembled complete genomes for multiple new genera, including two species that produce the cytotoxic polyketides pateamine and mycalamide, as well as a third high-abundance symbiont harboring a proteusin-type biosynthetic pathway that appears to encode a new polytheonamide-like compound. We also identified an additional 188 biosynthetic gene clusters, including a pathway for biosynthesis of peloruside. These re-sults suggest that multiple species cooperatively contribute to defensive symbiosis in M. hentscheli and reveal that the taxonomic diversity of secondary-metabolite-producing sponge symbionts is larger and richer than previously recognized. IMPORTANCE Mycale hentscheli is a marine sponge that is rich in bioactive small mol-ecules. Here, we use direct metagenomic sequencing to elucidate highly complete and contiguous genomes for the major symbiotic bacteria of this sponge. We identify complete biosynthetic pathways for the three potent cytotoxic polyketides which have previously been isolated from M. hentscheli. Remarkably, and in contrast to previous studies of marine sponges, we attribute each of these metabolites to a different producing mi-crobe. We also find that the microbiome of M. hentscheli is stably maintained among in-dividuals, even over long periods of time. Collectively, our data suggest a cooperative mode of defensive symbiosis in which multiple symbiotic bacterial species cooperatively contribute to the defensive chemical arsenal of the holobiont.

scholarly journals Bacterial secondary metabolite biosynthetic potential in soil varies with phylum, depth, and vegetation type

2019 ◽  
Author(s):  
Allison M. Sharrar ◽  
Alexander Crits-Christoph ◽  
Raphaël Méheust ◽  
Spencer Diamond ◽  
Evan P. Starr ◽  
...  
Keyword(s):  
Secondary Metabolite ◽  
Vegetation Type ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Metagenomic Sequencing ◽  
Soil Bacterial Diversity ◽  
Community Members ◽  
Clinical Value ◽  
Specialized Metabolites ◽  
Shallow Soils

AbstractBacteria isolated from soils are major sources of specialized metabolites, including antibiotics and other compounds with clinical value that likely shape interactions among microbial community members and impact biogeochemical cycles. Yet, isolated lineages represent a small fraction of all soil bacterial diversity. It remains unclear how the production of specialized metabolites varies across the phylogenetic diversity of bacterial species in soils, and whether the genetic potential for production of these metabolites differs with soil type. We sampled soils and saprolite from three sites in a northern California Critical Zone Observatory with varying vegetation and bedrock characteristics and used metagenomic sequencing and assembly to reconstruct 1,334 microbial genomes containing diverse biosynthetic gene clusters (BGCs) for secondary metabolite production. We obtained genomes for prolific producers of secondary metabolites, including novel groups within the Actinobacteria, Chloroflexi and candidate phylum Dormibactereota. Surprisingly, one genome of a Candidate Phyla Radiation bacterium encoded for a ribosomally synthesized linear azole/azoline-containing peptide, a capacity we found in other publicly available CPR bacterial genomes. Overall, bacteria with higher biosynthetic potential were enriched in shallow soils and grassland soils, with patterns of abundance of BGC type varying by taxonomy.

scholarly journals Metagenomic Exploration of the Marine Sponge Mycale hentscheli Uncovers Multiple Polyketide-Producing Bacterial Symbionts

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Mathew A. Storey ◽  
Sarah K. Andreassend ◽  
Joe Bracegirdle ◽  
Alistair Brown ◽  
Robert A. Keyzers ◽  
...  
Keyword(s):  
Marine Sponge ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Taxonomic Diversity ◽  
Marine Sponges ◽  
Metagenomic Sequencing ◽  
Content Type ◽  
Defensive Symbiosis ◽  
Long Read ◽  
Mycale Hentscheli

ABSTRACT Marine sponges have been a prolific source of unique bioactive compounds that are presumed to act as a deterrent to predation. Many of these compounds have potential therapeutic applications; however, the lack of efficient and sustainable synthetic routes frequently limits clinical development. Here, we describe a metagenomic investigation of Mycale hentscheli, a chemically gifted marine sponge that possesses multiple distinct chemotypes. We applied shotgun metagenomic sequencing, hybrid assembly of short- and long-read data, and metagenomic binning to obtain a comprehensive picture of the microbiome of five specimens, spanning three chemotypes. Our data revealed multiple producing species, each having relatively modest secondary metabolomes, that contribute collectively to the chemical arsenal of the holobiont. We assembled complete genomes for multiple new genera, including two species that produce the cytotoxic polyketides pateamine and mycalamide, as well as a third high-abundance symbiont harboring a proteusin-type biosynthetic pathway that appears to encode a new polytheonamide-like compound. We also identified an additional 188 biosynthetic gene clusters, including a pathway for biosynthesis of peloruside. These results suggest that multiple species cooperatively contribute to defensive symbiosis in M. hentscheli and reveal that the taxonomic diversity of secondary-metabolite-producing sponge symbionts is larger and richer than previously recognized. IMPORTANCE Mycale hentscheli is a marine sponge that is rich in bioactive small molecules. Here, we use direct metagenomic sequencing to elucidate highly complete and contiguous genomes for the major symbiotic bacteria of this sponge. We identify complete biosynthetic pathways for the three potent cytotoxic polyketides which have previously been isolated from M. hentscheli. Remarkably, and in contrast to previous studies of marine sponges, we attribute each of these metabolites to a different producing microbe. We also find that the microbiome of M. hentscheli is stably maintained among individuals, even over long periods of time. Collectively, our data suggest a cooperative mode of defensive symbiosis in which multiple symbiotic bacterial species cooperatively contribute to the defensive chemical arsenal of the holobiont.

scholarly journals Ancient Bacterial Class Alphaproteobacteria Cytochrome P450 Monooxygenases Can Be Found in Other Bacterial Species

2021 ◽  
Vol 22 (11) ◽  
pp. 5542
Author(s):  
Nomfundo Nzuza ◽  
Tiara Padayachee ◽  
Puleng Rosinah Syed ◽  
Justyna Dorota Kryś ◽  
Wanping Chen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Side Chain ◽  
Cytochrome P450 Monooxygenases ◽  
Biosynthetic Gene Clusters ◽  
Genome Data ◽  
P450 Monooxygenases ◽  
Large Numbers ◽  
Cyanobacterial Species

Cytochrome P450 monooxygenases (CYPs/P450s), heme-thiolate proteins, are well-known players in the generation of chemicals valuable to humans and as a drug target against pathogens. Understanding the evolution of P450s in a bacterial population is gaining momentum. In this study, we report comprehensive analysis of P450s in the ancient group of the bacterial class Alphaproteobacteria. Genome data mining and annotation of P450s in 599 alphaproteobacterial species belonging to 164 genera revealed the presence of P450s in only 241 species belonging to 82 genera that are grouped into 143 P450 families and 214 P450 subfamilies, including 77 new P450 families. Alphaproteobacterial species have the highest average number of P450s compared to Firmicutes species and cyanobacterial species. The lowest percentage of alphaproteobacterial species P450s (2.4%) was found to be part of secondary metabolite biosynthetic gene clusters (BGCs), compared other bacterial species, indicating that during evolution large numbers of P450s became part of BGCs in other bacterial species. Our study identified that some of the P450 families found in alphaproteobacterial species were passed to other bacterial species. This is the first study to report on the identification of CYP125 P450, cholesterol and cholest-4-en-3-one hydroxylase in alphaproteobacterial species (Phenylobacterium zucineum) and to predict cholesterol side-chain oxidation capability (based on homolog proteins) by P. zucineum.

scholarly journals Metagenomic exploration of the marine sponge mycale hentscheli uncovers multiple polyketide-producing bacterial symbionts

2020 ◽  
Author(s):  
Mathew Storey ◽  
SK Andreassend ◽  
Joe Bracegirdle ◽  
Alistair Brown ◽  
Robert Keyzers ◽  
...  
Keyword(s):  
Marine Sponge ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Taxonomic Diversity ◽  
Marine Sponges ◽  
Metagenomic Sequencing ◽  
Defensive Symbiosis ◽  
Long Read ◽  
Comprehensive Picture ◽  
Mycale Hentscheli

© 2020 Storey et al. Marine sponges have been a prolific source of unique bioactive compounds that are presumed to act as a deterrent to predation. Many of these compounds have potential therapeutic applications; however, the lack of efficient and sustainable synthetic routes frequently limits clinical development. Here, we describe a metag-enomic investigation of Mycale hentscheli, a chemically gifted marine sponge that pos-sesses multiple distinct chemotypes. We applied shotgun metagenomic sequencing, hybrid assembly of short-and long-read data, and metagenomic binning to obtain a comprehensive picture of the microbiome of five specimens, spanning three chemo-types. Our data revealed multiple producing species, each having relatively modest secondary metabolomes, that contribute collectively to the chemical arsenal of the holo-biont. We assembled complete genomes for multiple new genera, including two species that produce the cytotoxic polyketides pateamine and mycalamide, as well as a third high-abundance symbiont harboring a proteusin-type biosynthetic pathway that appears to encode a new polytheonamide-like compound. We also identified an additional 188 biosynthetic gene clusters, including a pathway for biosynthesis of peloruside. These re-sults suggest that multiple species cooperatively contribute to defensive symbiosis in M. hentscheli and reveal that the taxonomic diversity of secondary-metabolite-producing sponge symbionts is larger and richer than previously recognized. IMPORTANCE Mycale hentscheli is a marine sponge that is rich in bioactive small mol-ecules. Here, we use direct metagenomic sequencing to elucidate highly complete and contiguous genomes for the major symbiotic bacteria of this sponge. We identify complete biosynthetic pathways for the three potent cytotoxic polyketides which have previously been isolated from M. hentscheli. Remarkably, and in contrast to previous studies of marine sponges, we attribute each of these metabolites to a different producing mi-crobe. We also find that the microbiome of M. hentscheli is stably maintained among in-dividuals, even over long periods of time. Collectively, our data suggest a cooperative mode of defensive symbiosis in which multiple symbiotic bacterial species cooperatively contribute to the defensive chemical arsenal of the holobiont.

scholarly journals Understanding the evolutionary origins of bacterial natural products with immunosuppressant properties

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Natural Products ◽  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Human Body ◽  
Immune Cells ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Drug Candidates

Actinobacteria and streptomyces are known to produce a variety of natural products, some of which confer antibiotic or immunosuppressive activities. While it is understandable that microbes develop the ability to synthesize molecules such as antibiotics that attack other competing microbes, but why would a secondary metabolite (natural product) synthesized by a microbe confer immunosuppressive activities? Was the capability to synthesize such a molecule endowed by evolution in the context of enabling microbes to develop resistance to immune cells of the human body? Or did the capability come from the need to colonize human body surfaces or gut to gain a survival niche for the microbe? Given that actinobacteria and streptomyces are soil microbes not usually associated with human body surfaces, could their biosynthetic capability for particular immunosuppressants arise from horizontal gene transfer from bacteria that colonize human body surfaces and subsequently develop the ability to synthesize the pertinent compounds through evolution? An alternate line of thinking on this issue touches on the possibility that microbes could encounter analogs of immuno-active molecules in their natural environment. Such molecules might elicit undesired physiological effects on the microbes, which place a selection pressure on microbes to develop countermeasures to the immuno-active molecules through mutations. Hence, through evolution, microbes could have developed the capability to synthesize secondary metabolites able to bind analogs of immuno-active molecules and help sequester them or quench their bioactivity. Subsequent profiling of such secondary metabolites in drug discovery efforts could have uncovered compounds with immunosuppressant activity which are originally developed for counteracting analogs of immuno-active molecules in the environment. It has to be recognized that analogs of immuno-active compounds remain somewhat dissimilar to immune compounds secreted by human immune cells, but they likely share common motifs for protein-secondary metabolite interactions. Direct evidence of the evolution of natural products with immunosuppressant activities could only be obtained from challenging suitable bacterial species with immuno-active molecules. Long cultivation experiments with multiple generations may result in the evolution of biosynthetic gene clusters for the synthesis of natural products able to sequester or quench immuno-active molecules. But, on the another hand, understanding relative binding affinities between a library of natural products and immuno-active molecules from humans would suggest drug candidates and their biosynthetic gene clusters. Subsequent phylogenetic analysis of cluster genes with their homologs from other species may yield insights into the evolution of genes and their putative function.

scholarly journals Deciphering the Microbial Taxonomy and Functionality of Two Diverse Mangrove Ecosystems and Their Potential Abilities To Produce Bioactive Compounds

mSystems ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Shuilin Liao ◽  
Yayu Wang ◽  
Huan Liu ◽  
Guangyi Fan ◽  
Sunil Kumar Sahu ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
De Novo ◽  
Southern China ◽  
Sulfur Metabolism ◽  
Gene Clusters ◽  
Metagenomic Sequencing ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Mangrove Ecosystems ◽  
Unique Genes

ABSTRACT Mangroves, as important and special ecosystems, create unique ecological environments for examining the microbial gene capacity and potential for producing bioactive compounds. However, little is known about the biogeochemical implications of microbiomes in mangrove ecosystems, especially the variations between pristine and anthropogenic mangroves. To elucidate this, we investigated the microbial taxonomic and functional shifts of the mangrove microbiomes and their potential for bioactive compounds in two different coastal mangrove ecosystems in southern China. A gene catalogue, including 87 million unique genes, was constructed, based on deep shotgun metagenomic sequencing. Differentially enriched bacterial and archaeal taxa between pristine mangroves (Guangxi) and anthropogenic mangroves (Shenzhen) were found. The Nitrospira and ammonia-oxidizing archaea, specifically, were more abundant in Shenzhen mangroves, while sulfate-reducing bacteria and methanogens were more abundant in Guangxi mangroves. The results of functional analysis were consistent with the taxonomic results, indicating that the Shenzhen mangrove microbiome has a higher abundance of genes involved in nitrogen metabolism while the Guangxi mangrove microbiome has a higher capacity for sulfur metabolism and methanogenesis. Biosynthetic gene clusters were identified in the metagenome data and in hundreds of de novo reconstructed nonredundant microbial genomes, respectively. Notably, we found different biosynthetic potential in different taxa, and we identified three high quality and novel Acidobacteria genomes with a large number of BGCs. In total, 67,278 unique genes were annotated with antibiotic resistance, indicating the prevalence and persistence in multidrug-resistant genes in the mangrove microbiome. IMPORTANCE This study comprehensively described the taxonomy and functionality of mangrove microbiomes, including their capacity for secondary metabolite biosynthesis and their ability to resist antibiotics. The microbial taxonomic and functional characteristics differed between geographical locations, corresponding to the environmental condition of two diverse mangrove regions. A large number of microbial biosynthetic gene clusters encoding novel bioactivities were found, and this can serve as a valuable resource to guide novel bioactive compound discovery for potential clinical uses.

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