Project description:In the present study, we developed a chemical method to produce dihydro nicotinamide mononucleotide (NMNH), which is the reduced-form of nicotinamide mononucleotide (NMN). We demonstrated that NMNH was a better nicotinamide adenine dinucleotide (NAD+) enhancer compared to NMN both in vitro and in vivo mediated by mononucleotide adenylyltransferase (NMNAT). Additionally, NMNH increased the reduced NAD (NADH) levels in cells and in mouse liver. Metabolomic analysis revealed that NMNH inhibited glycolysis and TCA cycle. In vitro experiments demonstrated that NMNH induced cell cycle arrest and suppressed cell growth. Nevertheless, NMNH treatment did not cause observable difference in mice. Taken together, our work demonstrates that NMNH is a potent NAD+ enhancer, and suppresses glycometabolism and cell growth.
Project description:Centromeres are functionally conserved chromosomal loci essential for proper chromosome segregation during cell division, yet they show high sequence diversity across species. A near universal feature of centromeres is the presence of repetitive sequences, such as satellites and transposable elements (TEs). Because of their rapidly evolving karyotypes, gibbons represent a compelling model to investigate divergence of functional centromere sequences across short evolutionary timescales. Previously, we identified a novel composite retrotransposon, LAVA, that is exclusive to gibbons and expanded within the centromere regions of one gibbon genus, Hoolock. In this study, we use ChIP-seq, RNA-seq and fluorescence in situ hybridization to comprehensively investigate the repeat content of centromeres of the four extant gibbon genera (Hoolock, Hylobates, Nomascus and Siamang). We find that CENP-A nucleosomes and the DNA-protein interface with the inner kinetochore are enriched in retroelements in all gibbon genera, rather than satellite DNA. We find that LAVA in Hoolock is enriched in the centromeres of most chromosomes and shows centromere- and species-specific sequence and structural differences compared to other genera, potentially as a result of its co-option to a centromeric function. In contrast, we found that a centromeric retroelement-derived macrosatellite, SST1, corresponds with chromosome breakpoint reuse across gibbons and shows high sequence conservation across genera. Finally, using de novo assembly of centromere-specific sequences, we determine that transcripts originating from gibbon centromeres recapitulate species-specific TE diversity. Combined, our data reveals dynamic, species-specific shifts in repeat content that define gibbon centromeres and coincide with the extensive karyotypic diversity observed within this lineage.
2021-05-24 | GSE161308 | GEO
Project description:Lichens at the US National Herbarium (NMNH, Smithsonian Institution)
Project description:The need for species identification and taxonomic discovery has led to the development of innovative technologies for large-scale plant identification. DNA barcoding has been useful, but fails to distinguish among many species in species-rich plant genera, particularly in tropical regions. Here, we show that chemical fingerprinting, or “chemocoding”, has great potential for plant identification in challenging tropical biomes. Using untargeted metabolomics in combination with multivariate analysis, we constructed species-level fingerprints, which we define as chemocoding. We evaluated the utility of chemocoding with species that were defined morphologically and subject to next-generation DNA sequencing in the diverse and recently radiated neotropical genus, Inga (Leguminosae), both at single study sites and across broad geographic scales. Our results show that chemocoding is a robust method for distinguishing morphologically similar species at a single site and for identifying widespread species across continental-scale ranges. Given that species are the fundamental unit of analysis for conservation and biodiversity research, the development of accurate identification methods is essential. We suggest that chemocoding will be a valuable additional source of data for a quick identification of plants, especially for groups where other methods fall short.
Project description:Cellular barcoding using heritable synthetic barcodes coupled to high throughput sequencing is a powerful technique for the accurate tracing of clonal lineages in a wide variety of biological contexts. Recent studies have integrated cellular barcoding with a single-cell transcriptomics readout, extending the capabilities of these lineage tracing methods to the single-cell level. However there remains a lack of scalable and standardised open-source tools to pre-process and visualise both bulk and single-cell level cellular barcoding datasets. Here, we describe bartools, an open-source R-based toolkit that streamlines the pre-processing, analysis and visualisation of synthetic cellular barcoding datasets. In addition, we developed BARtab, a portable and scalable Nextflow pipeline that automates upstream barcode extraction, quality control, filtering and enumeration from high throughput sequencing data. In addition to population-level cellular barcoding datasets, BARtab and bartools contain methods for the extraction, annotation, and visualisation of transcribed barcodes from single-cell RNA-seq and spatial transcriptomics experiments, thus extending the analytical toolbox to also support novel expressed cellular barcoding methodologies. We showcase the integrated BARtab and bartools workflow through the analysis of bulk, single-cell, and spatial transcriptomics cellular barcoding datasets.