Project description:Metagenomic approaches have revealed unprecedented genetic diversity within microbial communities across vast expanses of the world’s oceans. Linking this genetic diversity with key metabolic and cellular activities of microbial assemblages is a fundamental challenge. Here we report on a collaborative effort to design MicroTOOLs (Microbiological Targets for Ocean Observing Laboratories), a high-density oligonucleotide microarray that targets functional genes of diverse taxa in pelagic and coastal marine microbial communities. MicroTOOLs integrates nucleotide sequence information from disparate data types: genomes, PCR-amplicons, metagenomes, and metatranscriptomes. It targets 19 400 unique sequences over 145 different genes that are relevant to stress responses and microbial metabolism across the three domains of life and viruses. MicroTOOLs was used in a proof-of-concept experiment that compared the functional responses of microbial communities following Fe and P enrichments of surface water samples from the North Pacific Subtropical Gyre. We detected transcription of 68% of the gene targets across major taxonomic groups, and the pattern of transcription indicated relief from Fe limitation and transition to N limitation in some taxa. Prochlorococcus (eHLI), Synechococcus (sub-cluster 5.3) and Alphaproteobacteria SAR11 clade (HIMB59) showed the strongest responses to the Fe enrichment. In addition, members of uncharacterized lineages also responded. The MicroTOOLs microarray provides a robust tool for comprehensive characterization of major functional groups of microbes in the open ocean, and the design can be easily amended for specific environments and research questions.
Project description:The dynamically organized chromatin complexes often involve multiplex chromatin interactions and sometimes chromatin-associated RNA (caRNA). Chromatin complex compositions change during cellular differentiation and aging, and are expected to be highly heterogeneous among terminally differentiated single cells. Here we introduce the Multi-Nucleic Acid Interaction Mapping in Single Cell (MUSIC) technique for concurrent profiling of multiplex chromatin interactions, gene expression, and RNA-chromatin associations within individual nuclei. Applied to 14 human frontal cortex samples from elderly donors, MUSIC delineates diverse cortical cell types and states. We observed the nuclei exhibiting fewer short-range chromatin interactions are correlated with an “older” transcriptomic signature and with Alzheimer’s pathology. Furthermore, the cell type exhibiting chromatin contacts between cis expression quantitative trait loci (cis eQTLs) and a promoter tends to be the cell type where these cis eQTLs specifically affect their target gene’s expression. Additionally, the female cortical cells exhibit highly heterogeneous interactions between the XIST non-coding RNA and Chromosome X, along with diverse spatial organizations of the X chromosomes. MUSIC presents a potent tool for exploring chromatin architecture and transcription at cellular resolution in complex tissues.
Project description:Centromeric repetitive DNA sequences are highly variable during evolution, which are the hub for genome stability in almost all the eukaryotic organisms. However, how centromeric repeat sequences diverge rapidly among closely related species and populations, and how polyploidy contributed to the diversity of centromere among co-evolved subgenomes are largely unknown. Here, we applied the Brachypodium system to investigate the track of centromere evolution within this taxa, and their adaptation to alloploidization process. Subgenome divergent centromeric satellite repeat were discovered in tetraploid B. hybridum, and this divergent was originated form their two diploid progenitors. Furthermore, differential sequences influence the association sites with CENH3 nucleosomes on the monomer satellite repeats, and positioning of CENH3 nucleosomes on the satellite DNA are stable in each subgenome after alloploidization. Only minor intrasubgenomic variations were observed on these satellite repeats from diploid to tetraploid in B. hybridum, and no evident intersubgenomic transfer of centromeric satellite repeats after alloploidization. Pan-genome analysis reveals that the general principle of centromere dynamic within the populations in Brachypodium genomes with different polyploidy level. Our results provide an unprecedented information regarding the genomic and functional diversity of centromeric repeat DNA during evolution.
Project description:Microarrays have become a powerful tool for DNA-based molecular diagnostics and identification of pathogens. However, most of them target a limited range of organisms and are generally based on only one or very few genes for organism identification. Although such microarrays are proven tools for species identification, they suffer from the fact that identification is only possible for organisms for which probes were specifically pre-developed. Furthermore, this approach often leads to problems with taxonomic-level resolution with insufficient diagnostic differences between closely related taxa found in the commonly used DNA sequences. An alternative strategy is to use the hybridisation pattern generated by many different anonymous markers distributed over the entire genome for identification based on comparison to a type database. We realised this strategy using a high density microarray containing 95,000 different 13-mer probes. Here, we demonstrate the specificity of our microarray based on results obtained with nine different bacterial species and strains. The hybridisation patterns allowed clear differentiation at the strain and even variant level. The reproducibility of our system was high as shown by high correlation coefficients between replicates, despite the occurrence of mismatch hybridisation. The results indicate the potential for identification of all bacterial taxa at the subspecies level using our universal microarray.
2010-03-16 | GSE15391 | GEO
Project description:Engineering Diverse Fatty Acid Compositions of Phospholipids in Escherichia coli
Project description:Our analysis identifies intratumoral components that are predominantly tumor cells, fibroblasts, myeloid cells, stromal cells that express neural stem cell (NSC) markers, with minor populations of oligodendrocytes (oligo) and T cells. Different samples present diverse cell compositions, indicating the underlying cellular interactions that affect different cellular infiltration within TME. Importantly, we identify the tumor-associated fibroblasts in both in-house and external scRNA-seq datasets that 1) highly expresses type I collagen genes; 2) dominates the cell-cell interactions in TME through the type I collagen signaling axis; and 3) remodels the TME to a collagen-I-rich extracellular matrix (ECM) similar to the original TME at the primary sites. We also observe the M1 activation of the native microglial cells and the infiltrated macrophages, which may create a proinflammatory TME and be responsible for the high expression of collagen type I in fibroblasts. Moreover, the tumor cell-specific receptors are significantly associated with patients’ survival in both brain metastasis and the native glioblastoma cases. Overall, our analyses identify the type I collagen secreting tumor-associated fibroblasts as a key mediator in metastatic brain tumors and reveal the involved tumor receptors associated with patients’ survival. Our discoveries provide potential biomarkers for effective therapeutic targets and intervention strategies.
2023-07-07 | GSE234832 | GEO
Project description:Enriched PHA producers with different VFA compositions