Biology subjects

Figueroa-Gonzalez, P. A.

Publications and source records attributed to Figueroa-Gonzalez, P. A..

4 recordsLinked to original sources

bioRxiv2023

Metaproteogenomics resolution of a high-CO2 aquifer community suggests an active symbiotic lifestyle of groundwater Gracilibacteria

BackgroundBacteria of the Candidate Phyla Radiation (CPR), constituting about 25% of the bacterial biodiversity, are characterized by small cell size and patchy genomes without complete key metabolic pathways, suggesting a symbiotic lifestyle. Gracilibacteria (BD1-5), which are part of the CPR branch, possess alternate coded genomes and have not yet been cultivated. However, besides genomic evidence, little is known about the lifestyle of Gracilibacteria, their temporal dynamics, and activity in natural ecosystems, particularly in groundwater, where they were initially been genomically resolved. Therefore, we here aimed to investigate Gracilibacteria activity in situ and to discern expressed genes involved in their lifestyle, using the metaproteogenome of Gracilibacteria as a function of time in the cold-water geyser Wallender Born in the Volcanic Eifel region in Germany. ResultsWe coupled genome-resolved metagenomics and metaproteomics to investigate a cold-water geyser microbial community enriched in Gracilibacteria across a 12-day time-series. Groundwater was collected and sequentially filtered to fraction CPR and other bacteria. Based on 670 Gbps of metagenomic data, 1129 different ribosomal protein S3 marker genes and 751 high-quality genomes (123 population genomes after dereplication), we identified dominant bacteria belonging to Galionellales and Gracilibacteria along with keystone microbes, which were low in genomic abundance but substantially contributing to proteomic abundance. Seven high-quality Gracilibacteria genomes showed typical limitations, such as limited amino acid or nucleotide synthesis, in their central metabolism but no co-occurrence with potential hosts. The genomes of these Gracilibacteria encoded for a high number of proteins related to a symbiotic or even predatory lifestyle, e.g., type IV and type II secretion system subunits and features related to cell-cell interactions and cell motility, which were also detected on protein level. ConclusionsCoupling metagenomics to metaproteomics enabled us to identify microbial keystone taxa in a high-CO2 aquifer, and to reveal microbial dynamics of Gracilibacteria. We posit that Gracilibacteria might be successful microbial predators in this ecosystem, potentially aiding in population control of this highly perturbed microbial geyser community from the deep biosphere.

ecology↗

bioRxiv2021

The economical lifestyle of CPR bacteria in groundwater allows little preference for environmental drivers

The highly diverse Cand. Patescibacteria are predicted to have minimal biosynthetic and metabolic pathways, which hinders understanding of how their populations differentiate to environmental drivers or host organisms. Their metabolic traits to cope with oxidative stress are largely unknown. Here, we utilized genome-resolved metagenomics to investigate the adaptive genome repertoire of Patescibacteria in oxic and anoxic groundwaters, and to infer putative host ranges. Within six groundwater wells, Cand. Patescibacteria was the most dominant (up to 79%) super-phylum across 32 metagenomes obtained from sequential 0.2 and 0.1 {micro}m filtration. Of the reconstructed 1275 metagenome-assembled genomes (MAGs), 291 high-quality MAGs were classified as Cand. Patescibacteria. Cand. Paceibacteria and Cand. Microgenomates were enriched exclusively in the 0.1 {micro}m fractions, whereas candidate division ABY1 and Cand. Gracilibacteria were enriched in the 0.2 {micro}m fractions. Patescibacteria enriched in the smaller 0.1 {micro}m filter fractions had 22% smaller genomes, 13.4% lower replication measures, higher fraction of rod-shape determining proteins, and genomic features suggesting type IV pili mediated cell-cell attachments. Near-surface wells harbored Patescibacteria with higher replication rates than anoxic downstream wells characterized by longer water residence time. Except prevalence of superoxide dismutase genes in Patescibacteria MAGs enriched in oxic groundwaters (83%), no major metabolic or phylogenetic differences were observed based on oxygen concentrations. The most abundant Patescibacteria MAG in oxic groundwater encoded a nitrate transporter, nitrite reductase, and F-type ATPase, suggesting an alternative energy conservation mechanism. Patescibacteria consistently co-occurred with one another or with members of phyla Nanoarchaeota, Bacteroidota, Nitrospirota, and Omnitrophota. However, only 8% of MAGs showed highly significant one-to-one association, mostly with Omnitrophota. Genes coding for motility and transport functions in certain Patescibacteria were highly similar to genes from other phyla (Omnitrophota, Proteobacteria and Nanoarchaeota). Other than genes to cope with oxidative stress, we found little genomic evidence for niche adaptation of Patescibacteria to oxic or anoxic groundwaters. Given that we could detect specific host preference only for a few MAGs, we propose that the majority of Patescibacteria can attach to multiple hosts just long enough to loot or exchange supplies with an economic lifestyle of little preference for geochemical conditions.

microbiology↗

bioRxiv2020

Genome-informed microscopy reveals infections of uncultivated carbon-fixing archaea by lytic viruses in Earth's crust

The continental subsurface houses a major portion of lifes abundance and diversity, yet little is known about viruses infecting microbes that reside there. Here, we used a combination of metagenomics and genome-informed microscopy to show that highly abundant carbon-fixing organisms of the uncultivated genus Candidatus Altiarchaeum are frequent targets of previously unrecognized viruses in the deep subsurface. Analysis of CRISPR spacer matches displayed resistances of Ca. Altiarchaea against eight predicted viral clades, which showed genomic relatedness across continents but little similarity to previously identified viruses. Based on metagenomic information, we tagged and imaged a putatively viral genome rich in protospacers using fluorescence microscopy. Virus-targeted genomeFISH revealed a lytic lifestyle of the respective virus and challenges previous predictions that lysogeny prevails as the dominant viral lifestyle in the subsurface. CRISPR development over time and imaging of 18 samples from one subsurface ecosystem suggest a sophisticated interplay of viral diversification and adapting CRISPR-mediated resistances of Ca. Altiarchaeum. We conclude that infections of primary producers with lytic viruses followed by cell lysis potentially jump-start heterotrophic carbon cycling in these subsurface ecosystems.

microbiology↗

bioRxiv2020

Geological degassing enhances microbial metabolism in the continental subsurface

Mantle degassing provides a substantial amount of reduced and oxidized gases shaping microbial metabolism at volcanic sites across the globe, yet little is known about its impact on microbial life under non-thermal conditions. Here, we characterized deep subsurface fluids from a cold-water geyser driven by mantle degassing using genome-resolved metagenomics to investigate how the gases impact the metabolism and activity of indigenous microbes compared to non-impacted sites. While species-specific analyses of Altiarchaeota suggest site-specific adaptations and a particular biogeographic pattern, chemolithoautotrophic core features of the communities appeared to be conserved across 17 groundwater ecosystems between 5 and 3200 m depth. We identified a significant negative correlation between ecosystem depth and bacterial replication, except for samples impacted by high amounts of subsurface gases, which exhibited near-surface activity. Our results suggest that geological degassing leads to higher nutrient flows and microbial activity in the deep subsurface than previously estimated.

microbiology↗