Project description:Bacterial outer membrane vesicles (OMVs) have important biological roles in pathogenesis and intercellular interactions, but a general mechanism of OMV formation is lacking. Here we show that the VacJ/Yrb ABC transport system, a proposed phospholipid (PL) transporter, is involved in OMV formation. Deletion or repression of VacJ/Yrb increases OMV production in two distantly related Gram-negative bacteria, Haemophilus influenzae and Vibrio cholerae. Within our studies we also analyzed the proteome of the OMV and outer membrane (OM) and found no massive alteration in Haemophilus influenzae Rd KW20, Rd ∆yrbE and Rd ∆vacJ. Lipidome analyses demonstrate that OMVs from VacJ/Yrb-defective mutants in H. influenzae are enriched in PLs and certain fatty acids. Furthermore, we demonstrate that OMV production and regulation of the VacJ/Yrb ABC transport system respond to iron starvation. Our results suggest a new general mechanism of OMV biogenesis based on PL accumulation in the outer leaflet of the outer membrane. This mechanism is highly conserved among Gram-negative bacteria, provides a means for regulation, can account for OMV formation under all growth conditions, and might have important pathophysiological roles in vivo.
Project description:Electrical stimulation of the retina following photoreceptor degeneration in diseases such as retinitis pigmentosa and age-related macular degeneration has become a promising therapeutic strategy for the restoration of vision. Many retinal neurons remain functional following photoreceptor degeneration; however, the responses of the different classes of cells to electrical stimuli have not been fully investigated. Using whole-cell patch clamp electrophysiology in retinal slices we investigated the response to electrical stimulation of cells of the inner nuclear layer (INL), pre-synaptic to retinal ganglion cells, in wild-type and retinally degenerate (rd/rd) mice. The responses of these cells to electrical stimulation were extremely varied, with both extrinsic and intrinsic evoked responses observed. Further examination of the intrinsically evoked responses revealed direct activation of both voltage-gated Na(+) channels and K(+) channels. The expression of these channels, which is particularly varied between INL cells, and the stimulus intensity, appears to dictate the polarity of the eventual response. Retinally degenerate animals showed similar responses to electrical stimulation of the retina to those of the wild-type, but the relative representation of each response type differed. The most striking difference between genotypes was the existence of a large amplitude oscillation in the majority of INL cells in rd/rd mice (as previously reported) that impacted on the signal to noise ratio following electrical stimulation. This confounding oscillation may significantly reduce the efficacy of electrical stimulation of the degenerate retina, and a greater understanding of its origin will potentially enable it to be dampened or eliminated.
Project description:BackgroundWhole-genome sequencing is increasingly used in clinical diagnosis of tuberculosis and study of Mycobacterium tuberculosis complex (MTC). MTC consists of several genetically homogenous mycobacteria species which can cause tuberculosis in humans and animals. Regions of difference (RDs) are commonly regarded as gold standard genetic markers for MTC classification.ResultsWe develop RD-Analyzer, a tool that can accurately infer the species and lineage of MTC isolates from sequence reads based on the presence and absence of a set of 31 RDs. Applied on a publicly available diverse set of 377 sequenced MTC isolates from known major species and lineages, RD-Analyzer achieved an accuracy of 98.14 % (370/377) in species prediction and a concordance of 98.47 % (257/261) in Mycobacterium tuberculosis lineage prediction compared to predictions based on single nucleotide polymorphism markers. By comparing respective sequencing read depths on each genomic position between isolates of different sublineages, we were able to identify the known RD markers in different sublineages of Lineage 4 and provide support for six potential delineating markers having high sensitivities and specificities for sublineage prediction. An extended version of RD-Analyzer was thus developed to allow user-defined RDs for lineage prediction.ConclusionsRD-Analyzer is a useful and accurate tool for species, lineage and sublineage prediction using known RDs of MTC from sequence reads and is extendable to accepting user-defined RDs for analysis. RD-Analyzer is written in Python and is freely available at https://github.com/xiaeryu/RD-Analyzer .
Project description:This experiment contains a subset of data from the BLUEPRINT Epigenome project ( http://www.blueprint-epigenome.eu ), which aims at producing a reference haemopoetic epigenomes for the research community. 29 samples of primary cells or cultured primary cells of different haemopoeitc lineages from cord blood are included in this experiment. This ArrayExpress record contains only meta-data. Raw data files have been archived at the European Genome-Phenome Archive (EGA, www.ebi.ac.uk/ega) by the consortium, with restricted access to protect sample donors' identity. The relevant accessions of EGA data sets is EGAD00001001165. Details on how to apply for data access via the BLUEPRINT data access committee are on the EGA data set pages. The mapping of samples to these EGA accessions can be found in the 'Sample Data Relationship Format' file of this ArrayExpress record. Information on individual samples and sequencing libraries can also be found on the BLUEPRINT data coordination centre (DCC) website: http://dcc.blueprint-epigenome.eu
Project description:This experiment contains a subset of data from the BLUEPRINT Epigenome project ( http://www.blueprint-epigenome.eu ), which aims at producing a reference haemopoetic epigenomes for the research community. 4 samples of primary cells from tonsil with cell surface markes CD20med/CD38high in young individuals (3 to 10 years old) are included in this experiment. This ArrayExpress record contains only meta-data. Raw data files have been archived at the European Genome-Phenome Archive (EGA, www.ebi.ac.uk/ega) by the consortium, with restricted access to protect sample donors' identity. The relevant accessions of EGA data sets is EGAD00001001523. Details on how to apply for data access via the BLUEPRINT data access committee are on the EGA data set pages. The mapping of samples to these EGA accessions can be found in the 'Sample Data Relationship Format' file of this ArrayExpress record. Information on individual samples and sequencing libraries can also be found on the BLUEPRINT data coordination centre (DCC) website: http://dcc.blueprint-epigenome.eu
Project description:Reprogramming of histone modification regulates gene expression and mammal preimplantation development. Trimethylation of lysine 4 on histone 3 (H3K4me3) has unique landscape in mouse oocytes and early embryos. However, the dynamics and function of H3K4me3 in livestock embryos remain unclear. To address how it is reprogrammed in domestic animals, we profiled changes of H3K4me3 during bovine early embryo development. Notably, the overall signal of H3K4me3 decreased during embryonic genome activation (EGA). By utilizing ultra-low-input native ChIP-seq (ULI-NChIP-seq) technology, we observed widespread broad H3K4me3 domains in oocytes and embryos. The signal of broad H3K4me3 began to decrease after fertilization and was lowest after EGA. Along with the removal of broad H3K4me3, deposition of H3K4me3 at promoter regions enhanced gradually. Besides, the transcriptional activity and signal of promoter H3K4me3 showed positive correlation after the erasure of broad H3K4me3 at 16-cell stage. Moreover, knocking down of demethylases KDM5A, KDM5B and KDM5C caused EGA delay and blastocyst formation failure. RNA-seq analysis revealed 47.8% down-regulated genes in knockdown embryos at 8/16-cell stage were EGA genes, and 63.1% of up-regulated genes were maternal transcripts. Particularly, the positive correlation between transcriptional activity and promoter H3K4me3 during EGA was restrained when knocking down of KDM5A, KDM5B and KDM5C. Overall, our work initiatively mapped the genomic reprogramming of H3K4me3 during bovine preimplantation development, and KDM5A/B/C played roles in modulating oocyte-to-embryonic transition (OET) through timely erasure of broad H3K4me3 domains far away from promoters.
Project description:Reprogramming of histone modification regulates gene expression and mammal preimplantation development. Trimethylation of lysine 4 on histone 3 (H3K4me3) has unique landscape in mouse oocytes and early embryos. However, the dynamics and function of H3K4me3 in livestock embryos remain unclear. To address how it is reprogrammed in domestic animals, we profiled changes of H3K4me3 during bovine early embryo development. Notably, the overall signal of H3K4me3 decreased during embryonic genome activation (EGA). By utilizing ultra-low-input native ChIP-seq (ULI-NChIP-seq) technology, we observed widespread broad H3K4me3 domains in oocytes and embryos. The signal of broad H3K4me3 began to decrease after fertilization and was lowest after EGA. Along with the removal of broad H3K4me3, deposition of H3K4me3 at promoter regions enhanced gradually. Besides, the transcriptional activity and signal of promoter H3K4me3 showed positive correlation after the erasure of broad H3K4me3 at 16-cell stage. Moreover, knocking down of demethylases KDM5A, KDM5B and KDM5C caused EGA delay and blastocyst formation failure. RNA-seq analysis revealed 47.8% down-regulated genes in knockdown embryos at 8/16-cell stage were EGA genes, and 63.1% of up-regulated genes were maternal transcripts. Particularly, the positive correlation between transcriptional activity and promoter H3K4me3 during EGA was restrained when knocking down of KDM5A, KDM5B and KDM5C. Overall, our work initiatively mapped the genomic reprogramming of H3K4me3 during bovine preimplantation development, and KDM5A/B/C played roles in modulating oocyte-to-embryonic transition (OET) through timely erasure of broad H3K4me3 domains far away from promoters.
Project description:This experiment contains a subset of data from the BLUEPRINT Epigenome project ( http://www.blueprint-epigenome.eu ), which aims at producing a reference haemopoetic epigenomes for the research community. 74 samples of primary cells or cultured primary cells of different haemopoeitc lineages from cord blood, venous blood, bone marrow and thymus are included in this experiment. This ArrayExpress record contains only meta-data. Raw data files have been archived at the European Genome-Phenome Archive (EGA, www.ebi.ac.uk/ega) by the consortium, with restricted access to protect sample donors' identity. There are 32 EGA data set accessions, which can be found under the Comment[EGA_DATA_SET] column in the 'Sample Data Relationship Format' (SDRF) file of this ArrayExpress record (http://www.ebi.ac.uk/arrayexpress/files/E-MTAB-3827/E-MTAB-3827.sdrf.txt). Details on how to apply for data access via the BLUEPRINT data access committee are on the EGA data set pages. Likewise, mapping of samples to these EGA accessions can be found in the SDRF file. Please note that the raw data files for 11 sequencing runs have yet been deposited at EGA, so they are marked with \\ot available\\ under the Comment[SUBMITTED_FILE_NAME] field in the SDRF file, and were included for the sake of completeness. Further iInformation on individual samples and sequencing libraries can also be found on the BLUEPRINT data coordination centre (DCC) website: http://dcc.blueprint-epigenome.eu\