Project description:This project aims to investigate the metabolic pathways expressed by the active microbial community occurring at the deep continental subsurface. Subsurface chemoLithoautotrophic Microbial Ecosystems (SLiMEs) under oligotrophic conditions are supported by H2; however, the overall ecological trophic structures of these communities are poorly understood. Some deep, fluid-filled fractures in the Witwatersrand Basin, South Africa appear to support inverted trophic pyramids wherein methanogens contributing <5% of the total DNA apparently produce CH4 that supports the rest of the community. Here we show the active metabolic relationships of one such trophic structure by combining metatranscriptomic assemblies, metaproteomic and stable isotopic data, and thermodynamic modeling. Four autotrophic β-proteobacteria genera that are capable of oxidizing sulfur by denitrification dominate. They co-occur with sulfate reducers, anaerobic methane oxidizers and methanogens, which each comprises <5% of the total community. Defining trophic levels of microbial chemolithoautotrophs by the number of transfers from the initial abiotic H2-driven CO2 fixation, we propose a top-down cascade influence of the metabolic consumers that enhances the fitness of the metabolic producers to explain the inverted biomass pyramid of a multitrophic SLiME. Symbiotic partnerships are pivotal in the deep biosphere on and potentially beyond the Earth.
Project description:The deep marine subsurface is one of the largest unexplored biospheres on Earth, where members of the phylum Chloroflexi are abundant and globally distributed. However, the deep-sea Chloroflexi have remained elusive to cultivation, hampering a more thorough understanding of their metabolisms. In this work, we have successfully isolated a representative of the phylum Chloroflexi, designated strain ZRK33, from deep-sea cold seep sediments. Phylogenetic analyses based on 16S rRNA genes, genomes, RpoB and EF-tu proteins indicated that strain ZRK33 represents a novel class within the phylum Chloroflexi, designated Sulfochloroflexia. We present a detailed description of the phenotypic traits, complete genome sequence and central metabolisms of the novel strain ZRK33. Notably, sulfate and thiosulfate could significantly promote the growth of the new isolate, possibly through accelerating the hydrolysis and uptake of saccharides. Thus, this result reveals that strain ZRK33 may play a crucial part in sulfur cycling in the deep-sea environments. Moreover, the putative genes associated with assimilatory and dissimilatory sulfate reduction are broadly distributed in the genomes of 27 metagenome-assembled genomes (MAGs) from deep-sea cold seep and hydrothermal vents sediments. Together, we propose that the deep marine subsurface Chloroflexi play key roles in sulfur cycling for the first time. This may concomitantly suggest an unsuspected availability of sulfur-containing compounds to allow for the high abundance of Chloroflexi in the deep sea.
Project description:Parasitism is a major ecological niche for a variety of nematodes. Multiple nematode lineages have specialized as pathogens, including deadly parasites of insects that are used in biological control. We have sequenced and analyzed the draft genomes and transcriptomes of the entomopathogenic nematode Steinernema carpocapsae and four congeners (S. scapterisci, S. monticolum, S. feltiae, S. glaseri) distantly related to Caenorhabditis elegans. We used these genomes to establish phylogenetic relationships, explore gene conservation across species, identify genes uniquely expanded in insect parasites, and to identify conserved non-coding regulatory motifs that influence similar biological processes. Protein domain analysis of these genomes reveals a striking expansion of numerous putative parasitism genes including certain protease and protease inhibitor families as well as fatty acid- and retinol-binding proteins. We identify rapid evolution and expansion of the important developmental Hox gene cluster and identify novel conserved non-coding regulatory motifs associated with orthologous genes in Steinernema and Caenorhabditis. The deep conservation of the network of non-coding DNA motifs between these two genera for a subset of orthologous genes involved in neurogenesis and embryonic development suggests that a kernel of protein-DNA relationships is conserved through nematode evolution. We analyzed the gene expression of a total of 24 RNA-seq samples from 3 nematode species( S. carpocapsae, S. feltiae, and C. elegans) for comparative analysis. We collected the RNA at four developmental time points (mixed embryo, L1, infective juvenile/dauer, young adult) for each species in replicates.
Project description:The Lucinidae is a large family of marine bivalves. They occur in diverse habitats from shallow-water seagrass sediments to deep-sea hydrothermal vents. All members of this family so far investigated host intracellular sulfur-oxidizing symbionts that belong to the Gammaproteobacteria. We recently discovered the capability for nitrogen fixation in draft genomes of the symbionts of Loripes lucinalis from the Bay of Fetovaia, Elba, Italy. With proteomics, we investigated whether the genes for nitrogen fixation are expressed by the symbionts.
Project description:Bathymodiolin mussels are a group of bivalves associated with deep-sea reducing habitats, such as hydrothermal vents and cold seeps. These mussels usually engage in an obligatory symbiosis with sulfur and/or methane oxidizing Gammaproteobacteria. In addition to these bacteria, Bathymodiolus heckerae that inhabit gas and oil seeps in Campeche Bay, the southern Gulf of Mexico, host bacteria phylogenetically with the Cycloclasticus genus. We recently discovered the capability for short-chain alkane degradation in draft genomes of symbiotic Cycloclasticus. With proteomics, we investigated whether the genes required for this process are expressed by the symbionts.
Project description:Hispanic/Latino populations possess a complex genetic structure that reflects recent admixture among and potentially ancient substructure within Native American, European, and West African source populations. Here, we quantify genome-wide patterns of SNP and haplotype variation among 100 individuals with ancestry from Ecuador, Colombia, Puerto Rico, and the Dominican Republic genotyped using Illumina technology. To investigate variations of continental ancestry between different Hispanic/Latino groups (using self-reported country-specific identification of individual, both parents, and all four grandparents) and within them from healthy controls represented in the New York Health Project Biorepository. Genotyped on the Illumina 610-Quad, which is identical to HumanHap550-v3 SNPs plus an additional ~60,000 SNPs for CNV, no CNV data is provided or was analyzed.