Cyanobacteria produce exopolysaccharides (EPSs) as an adaptative mechanism against ultraviolet ra... more Cyanobacteria produce exopolysaccharides (EPSs) as an adaptative mechanism against ultraviolet radiation and desiccation. Cellulose is present in the extracellular polymeric substance in some cyanobacteria genera and it has been proposed as a raw material for biofuel production. The goal of this work was to evaluate the cellulose presence in EPS of Atacama cyanobacteria strains and its use as an alternative and innovative biological source to produce bioethanol. The presence of cellulose was evaluated using techniques of molecular biology, bioinformatics, and electronic microscopy. The conserved motif D,D,D,35QXXRW, characteristic of processive β-glycosyltransferase in all cellulose-producing organisms, was identified in the genome of the LLA-10 strain. This is evidence that cellulose synthase in the LLA-10 strain is a functional enzyme. EPS from Atacama cyanobacteria was hydrolyzed by β-glucosidases (cellobiase and cellulase) and the released glucose was yeast-fermented to ethanol....
Atmospheric transport is critical to dispersal of microorganisms between habitats and this underp... more Atmospheric transport is critical to dispersal of microorganisms between habitats and this underpins resilience in terrestrial and marine ecosystems globally. A key unresolved question is whether microorganisms assemble to form a taxonomically distinct, geographically variable, and functionally adapted atmospheric microbiome. Here we characterised globalscale patterns of microbial taxonomic and functional diversity in air within and above the atmospheric boundary layer and in underlying soils. Bacterial and fungal assemblages in air were taxonomically structured and deviated significantly from purely stochastic assembly. Patterns differed with location and reflected underlying surface cover and environmental filtering. Source-tracking indicated a complex recruitment process involving local soils plus globally distributed inputs from drylands and the phyllosphere. Assemblages displayed stressresponse and metabolic traits relevant to survival in air, and taxonomic and functional diver...
ABSTRACTUnderstanding the mechanisms underlying microbial resistance and resilience to perturbati... more ABSTRACTUnderstanding the mechanisms underlying microbial resistance and resilience to perturbations is essential to predict the impact of climate change on Earth’s ecosystems. However, the resilience and adaptation mechanisms of microbial communities to natural perturbations remain relatively unexplored, particularly in extreme environments. The response of an extremophile community inhabiting halite (salt rocks) in the Atacama Desert to a catastrophic rainfall provided the opportunity to characterize and de-convolute the temporal response of a highly specialized community to a major disturbance. With shotgun metagenomic sequencing, we investigated the halite microbiome taxonomic composition and functional potential over a 4-year longitudinal study, uncovering the dynamics of the initial response and of the recovery of the community after a rainfall event. The observed changes can be recapitulated by two general modes of community shifts – a rapidType 1shift and a more gradualType ...
This study assessed the diversity of cultivable rock-associated fungi from Atacama Desert. Eighty... more This study assessed the diversity of cultivable rock-associated fungi from Atacama Desert. Eighty-one fungal isolates obtained were identified as 21 species from Ascomycota, sequencing different regions of fungal DNA. Cladosporium halotolerans, Penicillium chrysogenum and Penicillium citrinum were the most frequent species, which occur at least in four different altitudes. The diversity and similarity indices ranged in the fungal communities across the latitudinal gradient. The Fisher-α index displayed the higher values for the fungal communities obtained from the siltstone and fine matrix of pyroclastic rocks with finer grain size, which are more degraded. Twenty-one fungal extracts displayed activity against the different targets screened. The extract of Penicillium chrysogenum afforded the compounds α-linolenic acid and ergosterol endoperoxide, which were active against Cryptococcus neoformans and methicillin-resistance Staphylococcus aureus, respectively. Our study represents th...
SummaryThe Atacama Desert is one of the oldest and driest deserts in the world, and its hyper‐ari... more SummaryThe Atacama Desert is one of the oldest and driest deserts in the world, and its hyper‐arid core is described as ‘the most barren region imaginable’. We used a combination of high‐throughput sequencing and microscopy methods to characterize the endolithic microbial assemblages of halite pinnacles (salt rocks) collected in several hyper‐arid areas of the desert. We found communities dominated by archaea that relied on a single phylotype of Halothece cyanobacteria for primary production. A few other phylotypes of salt‐adapted bacteria and archaea, including Salinibacter, Halorhabdus, and Halococcus were major components of the halite communities, indicating specific adaptations to the unique halite environments. Multivariate statistical analyses of diversity metrics clearly separated the halite communities from that of the surrounding soil in the Yungay area. These analyses also revealed distribution patterns of halite communities correlated with atmospheric moisture. Microbial...
Substantial knowledge has accumulated on the microbiome of the hyperarid Atacama Desert during th... more Substantial knowledge has accumulated on the microbiome of the hyperarid Atacama Desert during the last two decades; however, information on Atacama free-living amoebae (FLA) is limited and increasing efforts are required. FLA are polyphyletic heterotrophic naked or testate protists that feed on organic matter, fungi, protozoa, and bacteria and may disseminate infections. Amoebae in Chile are represented by 416 taxa and 64 genera, and 29 taxa have been identified in arid shrub lands at the southern limit of the Atacama Desert, and Acanthamoeba are present in all the country’s regions. To expand our knowledge and to contribute to the biogeographic distribution of Atacama FLA, we report the dominant presence of members of the genus Acanthamoeba in water and sediment sampled at the Loa and Salado rivers in the pre-Andean zone of the Antofagasta Region, northern Chile, at sites 2500 m above sea level. We expect these observations and preliminary evidence of FLA presence in other wetland...
During mating, males provide not only the spermatozoa to fertilize the oocyte but also other stim... more During mating, males provide not only the spermatozoa to fertilize the oocyte but also other stimuli that are essential for initiating and maintaining the reproductive programme in females. In the mammalian oviduct, mating regulates sperm storage, egg transport, fertilization, early embryonic development, and oestradiol metabolism. However, the main molecules underlying these processes are poorly understood. Using microarray analyses, we identified 58 genes that were either induced or repressed by mating in the endosalpinx at 3 h post-stimulus. RT-qPCR confirmed that mating downregulated the expression of the Oas1h and Prim1 genes and upregulated the expression of the Ceacam1, Chad, Chst10, Slc5a3 and Slc26a4 genes. The functional category ‘cell-to-cell signalling and interaction’ was over-represented in this gene list. Network modelling identified TNF and all-trans retinoic acid (RA) as upstream regulators of the mating-induced transcriptional response, which was confirmed by intra...
Our knowledge on the Microbiology of the Atacama Desert has increased steadily and substantially ... more Our knowledge on the Microbiology of the Atacama Desert has increased steadily and substantially during the last two decades. This information now supports a paradigmatic change on the Atacama Desert from a sterile, uninhabitable territory to a hyperarid region colonized by a rich microbiota that includes extremophiles and extreme-tolerant microorganisms. Also, extensive reports are available on the prevalent physical and chemical environmental conditions, ecological niches and, the abundance, diversity and organization of the microbial life in the Atacama Desert. This territory is a highly desiccated environment due to the absence of regular rain events. Liquid water scarcity is the most serious environmental factor affecting the Atacama Desert microorganisms. The intense solar irradiation in this region contributes, in a synergistic fashion with desiccation, to limit the survival and growth of the microbial life. In order to overcome these two extreme conditions, successful microo...
SME 16 Montreal, 16th International Symposium on Microbial Ecology; Montreal (Canada); 21-26 Augu... more SME 16 Montreal, 16th International Symposium on Microbial Ecology; Montreal (Canada); 21-26 August 2016; http://www.isme-microbes.org/isme16
Cyanobacteria biomasses are sources of secondary metabolites and nutritious ingredients such as v... more Cyanobacteria biomasses are sources of secondary metabolites and nutritious ingredients such as vitamins, essential amino acids, and unsaturated fatty acids. Biochemical composition, presence of cyanotoxins and contaminants are major concerns to be addressed on such edible biomasses. Macrocolonies of a filamentous diazotrophic Nostoc species known as Llayta are found at Andean wetlands and consumed since pre-Columbian times in South America. Its biochemical composition has been previously conducted to assess their nutritious quality and cyanotoxicity. Macrocolonies of filamentous cyanobacteria are niches for colonization by diverse microorganisms; however, the Llayta microcolonies cyanosphere is unknown. Based on a culture-independent approach, we report the identification of members of the resilient microflora associated with Llayta trichomes after Gentamicin treatments. We have also reconstructed the genomes of the Llayta macrocolony-forming Nostoc sp. cyanobacterium (6,781,030 bp...
Cyanobacteria produce exopolysaccharides (EPSs) as an adaptative mechanism against ultraviolet ra... more Cyanobacteria produce exopolysaccharides (EPSs) as an adaptative mechanism against ultraviolet radiation and desiccation. Cellulose is present in the extracellular polymeric substance in some cyanobacteria genera and it has been proposed as a raw material for biofuel production. The goal of this work was to evaluate the cellulose presence in EPS of Atacama cyanobacteria strains and its use as an alternative and innovative biological source to produce bioethanol. The presence of cellulose was evaluated using techniques of molecular biology, bioinformatics, and electronic microscopy. The conserved motif D,D,D,35QXXRW, characteristic of processive β-glycosyltransferase in all cellulose-producing organisms, was identified in the genome of the LLA-10 strain. This is evidence that cellulose synthase in the LLA-10 strain is a functional enzyme. EPS from Atacama cyanobacteria was hydrolyzed by β-glucosidases (cellobiase and cellulase) and the released glucose was yeast-fermented to ethanol....
Atmospheric transport is critical to dispersal of microorganisms between habitats and this underp... more Atmospheric transport is critical to dispersal of microorganisms between habitats and this underpins resilience in terrestrial and marine ecosystems globally. A key unresolved question is whether microorganisms assemble to form a taxonomically distinct, geographically variable, and functionally adapted atmospheric microbiome. Here we characterised globalscale patterns of microbial taxonomic and functional diversity in air within and above the atmospheric boundary layer and in underlying soils. Bacterial and fungal assemblages in air were taxonomically structured and deviated significantly from purely stochastic assembly. Patterns differed with location and reflected underlying surface cover and environmental filtering. Source-tracking indicated a complex recruitment process involving local soils plus globally distributed inputs from drylands and the phyllosphere. Assemblages displayed stressresponse and metabolic traits relevant to survival in air, and taxonomic and functional diver...
ABSTRACTUnderstanding the mechanisms underlying microbial resistance and resilience to perturbati... more ABSTRACTUnderstanding the mechanisms underlying microbial resistance and resilience to perturbations is essential to predict the impact of climate change on Earth’s ecosystems. However, the resilience and adaptation mechanisms of microbial communities to natural perturbations remain relatively unexplored, particularly in extreme environments. The response of an extremophile community inhabiting halite (salt rocks) in the Atacama Desert to a catastrophic rainfall provided the opportunity to characterize and de-convolute the temporal response of a highly specialized community to a major disturbance. With shotgun metagenomic sequencing, we investigated the halite microbiome taxonomic composition and functional potential over a 4-year longitudinal study, uncovering the dynamics of the initial response and of the recovery of the community after a rainfall event. The observed changes can be recapitulated by two general modes of community shifts – a rapidType 1shift and a more gradualType ...
This study assessed the diversity of cultivable rock-associated fungi from Atacama Desert. Eighty... more This study assessed the diversity of cultivable rock-associated fungi from Atacama Desert. Eighty-one fungal isolates obtained were identified as 21 species from Ascomycota, sequencing different regions of fungal DNA. Cladosporium halotolerans, Penicillium chrysogenum and Penicillium citrinum were the most frequent species, which occur at least in four different altitudes. The diversity and similarity indices ranged in the fungal communities across the latitudinal gradient. The Fisher-α index displayed the higher values for the fungal communities obtained from the siltstone and fine matrix of pyroclastic rocks with finer grain size, which are more degraded. Twenty-one fungal extracts displayed activity against the different targets screened. The extract of Penicillium chrysogenum afforded the compounds α-linolenic acid and ergosterol endoperoxide, which were active against Cryptococcus neoformans and methicillin-resistance Staphylococcus aureus, respectively. Our study represents th...
SummaryThe Atacama Desert is one of the oldest and driest deserts in the world, and its hyper‐ari... more SummaryThe Atacama Desert is one of the oldest and driest deserts in the world, and its hyper‐arid core is described as ‘the most barren region imaginable’. We used a combination of high‐throughput sequencing and microscopy methods to characterize the endolithic microbial assemblages of halite pinnacles (salt rocks) collected in several hyper‐arid areas of the desert. We found communities dominated by archaea that relied on a single phylotype of Halothece cyanobacteria for primary production. A few other phylotypes of salt‐adapted bacteria and archaea, including Salinibacter, Halorhabdus, and Halococcus were major components of the halite communities, indicating specific adaptations to the unique halite environments. Multivariate statistical analyses of diversity metrics clearly separated the halite communities from that of the surrounding soil in the Yungay area. These analyses also revealed distribution patterns of halite communities correlated with atmospheric moisture. Microbial...
Substantial knowledge has accumulated on the microbiome of the hyperarid Atacama Desert during th... more Substantial knowledge has accumulated on the microbiome of the hyperarid Atacama Desert during the last two decades; however, information on Atacama free-living amoebae (FLA) is limited and increasing efforts are required. FLA are polyphyletic heterotrophic naked or testate protists that feed on organic matter, fungi, protozoa, and bacteria and may disseminate infections. Amoebae in Chile are represented by 416 taxa and 64 genera, and 29 taxa have been identified in arid shrub lands at the southern limit of the Atacama Desert, and Acanthamoeba are present in all the country’s regions. To expand our knowledge and to contribute to the biogeographic distribution of Atacama FLA, we report the dominant presence of members of the genus Acanthamoeba in water and sediment sampled at the Loa and Salado rivers in the pre-Andean zone of the Antofagasta Region, northern Chile, at sites 2500 m above sea level. We expect these observations and preliminary evidence of FLA presence in other wetland...
During mating, males provide not only the spermatozoa to fertilize the oocyte but also other stim... more During mating, males provide not only the spermatozoa to fertilize the oocyte but also other stimuli that are essential for initiating and maintaining the reproductive programme in females. In the mammalian oviduct, mating regulates sperm storage, egg transport, fertilization, early embryonic development, and oestradiol metabolism. However, the main molecules underlying these processes are poorly understood. Using microarray analyses, we identified 58 genes that were either induced or repressed by mating in the endosalpinx at 3 h post-stimulus. RT-qPCR confirmed that mating downregulated the expression of the Oas1h and Prim1 genes and upregulated the expression of the Ceacam1, Chad, Chst10, Slc5a3 and Slc26a4 genes. The functional category ‘cell-to-cell signalling and interaction’ was over-represented in this gene list. Network modelling identified TNF and all-trans retinoic acid (RA) as upstream regulators of the mating-induced transcriptional response, which was confirmed by intra...
Our knowledge on the Microbiology of the Atacama Desert has increased steadily and substantially ... more Our knowledge on the Microbiology of the Atacama Desert has increased steadily and substantially during the last two decades. This information now supports a paradigmatic change on the Atacama Desert from a sterile, uninhabitable territory to a hyperarid region colonized by a rich microbiota that includes extremophiles and extreme-tolerant microorganisms. Also, extensive reports are available on the prevalent physical and chemical environmental conditions, ecological niches and, the abundance, diversity and organization of the microbial life in the Atacama Desert. This territory is a highly desiccated environment due to the absence of regular rain events. Liquid water scarcity is the most serious environmental factor affecting the Atacama Desert microorganisms. The intense solar irradiation in this region contributes, in a synergistic fashion with desiccation, to limit the survival and growth of the microbial life. In order to overcome these two extreme conditions, successful microo...
SME 16 Montreal, 16th International Symposium on Microbial Ecology; Montreal (Canada); 21-26 Augu... more SME 16 Montreal, 16th International Symposium on Microbial Ecology; Montreal (Canada); 21-26 August 2016; http://www.isme-microbes.org/isme16
Cyanobacteria biomasses are sources of secondary metabolites and nutritious ingredients such as v... more Cyanobacteria biomasses are sources of secondary metabolites and nutritious ingredients such as vitamins, essential amino acids, and unsaturated fatty acids. Biochemical composition, presence of cyanotoxins and contaminants are major concerns to be addressed on such edible biomasses. Macrocolonies of a filamentous diazotrophic Nostoc species known as Llayta are found at Andean wetlands and consumed since pre-Columbian times in South America. Its biochemical composition has been previously conducted to assess their nutritious quality and cyanotoxicity. Macrocolonies of filamentous cyanobacteria are niches for colonization by diverse microorganisms; however, the Llayta microcolonies cyanosphere is unknown. Based on a culture-independent approach, we report the identification of members of the resilient microflora associated with Llayta trichomes after Gentamicin treatments. We have also reconstructed the genomes of the Llayta macrocolony-forming Nostoc sp. cyanobacterium (6,781,030 bp...
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Papers by Benito Gomez-silva