Project description:Metastasis is a major cause of mortality, and remains a final frontier in the search for a cure for cancer. While there has been much research on the ‘seed’ (metastatic tumor cells) and the ‘soil’ (colonized host tissue), interactions between metastatic cancer cells and stromal endothelial cells, which occur at multiple stages during metastasis, are less well understood. Here we report a dynamic regulation of the endothelium by cancer cells through the formation of nanoscale intercellular membrane bridges, which act as physical conduits for intercellular communication in vitro and in vivo, including horizontal transfer of microRNAs (miRNA). The communication between the tumor cell and the endothelium upregulates markers associated with pathological endothelium, which is reversed by pharmacological inhibition of these nanoscale conduits. These results lead us to define the notion of “metastatic hijack”: cancer cell-induced transformation of healthy endothelium into pathological endothelium via horizontal communication through the nanoscale conduits. Pharmacological perturbation of these nanoscale membrane bridges decreases metastatic foci in syngeneic- and human xenograft-breast cancer models. Targeting the formation of these nanoscale membrane bridges may potentially emerge as a new therapeutic opportunity in the management of metastatic cancer.
Project description:Pathways underlying miRNA biogenesis, degradation, and activity were established early in land plant evolution, but the 24-nt siRNA pathway that guides DNA methylation was incomplete in early land plants, especially lycophytes. We show that the functional diversification of key gene families such as DICER-LIKE and ARGONAUTE (AGO) as observed in angiosperms occurred early in land plants followed by parallel expansion of the AGO family in ferns and angiosperms. We uncovered an unexpected AGO family specific to lycophytes and ferns. Our phylogenetic analyses of miRNAs in lycophytes, bryophytes, ferns, and angiosperms refined the temporal origination of conserved miRNA families in land plants.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:Avian pathogenic Escherichia coli strains frequently cause extra-intestinal infections and are responsible for significant economic losses in the poultry industry worldwide. APEC isolates are closely related to human extraintestinal pathogenic E.coli strains and may also act as pathogens for humans. In this work, three type VI secretion systems were deleted to analyze which pathogenicity characteristics would change in the mutants, compared to wild type strain (SEPT 362). Four Avian Pathogenic Escherichia coli strains (one wild type and three deleted mutants) were grown at 37°C in Dulbecco´s Modified Eagle´s Media (DMEM) media until reach O.D 600 = 0.8, for RNA extraction and hybridization on Affymatrix microarrays.
Project description:Metastasis is a major cause of mortality, and remains a final frontier in the search for a cure for cancer. While there has been much research on the ‘seed’ (metastatic tumor cells) and the ‘soil’ (colonized host tissue), interactions between metastatic cancer cells and stromal endothelial cells, which occur at multiple stages during metastasis, are less well understood. Here we report a dynamic regulation of the endothelium by cancer cells through the formation of nanoscale intercellular membrane bridges, which act as physical conduits for intercellular communication in vitro and in vivo, including horizontal transfer of microRNAs (miRNA). The communication between the tumor cell and the endothelium upregulates markers associated with pathological endothelium, which is reversed by pharmacological inhibition of these nanoscale conduits. These results lead us to define the notion of “metastatic hijack”: cancer cell-induced transformation of healthy endothelium into pathological endothelium via horizontal communication through the nanoscale conduits. Pharmacological perturbation of these nanoscale membrane bridges decreases metastatic foci in syngeneic- and human xenograft-breast cancer models. Targeting the formation of these nanoscale membrane bridges may potentially emerge as a new therapeutic opportunity in the management of metastatic cancer. A miRNA microarray was used to evaluate the transport of endogenous microRNAs. The intercellular transfer-ve and intercellular transfer+ve samples were sorted from the same endothelial cell population with the only difference being the occurrence of intercellular transport. The heat map shows potential miRNA candidates for exogenous transfer on two independent biological replicates. These miRNA candidates were significantly up-regulated in the cells receiving transfer of intercellular contents. HUVECs that were not exposed to cancer cells were used as a baseline control.
Project description:Soil microorganisms act as gatekeepers for soil-atmosphere carbon exchange by balancing the accumulation and release of soil organic matter. However, poor understanding of the mechanisms responsible hinders the development of effective land management strategies to enhance soil carbon storage. Here we empirically test the link between microbial ecophysiological traits and topsoil carbon content across geographically distributed soils and land use contrasts. We discovered distinct pH-controls on microbial mechanisms of carbon accumulation. Land use intensification in low-pH soils that increased pH above a threshold (~ 6.2) lead to carbon loss through increased decomposition following alleviation of acid-retardation of microbial growth. However, loss of carbon with intensification in near neutral-pH soils was linked to decreased microbial biomass and reduced growth efficiency that was, in turn, related to tradeoffs with stress alleviation and resource acquisition. Thus, less intensive management practices in near neutral-pH soils have more potential for carbon storage through increased microbial growth efficiency; whereas, in acidic soils microbial growth is a bigger constraint on decomposition rates.
Project description:Background: Avian infectious bronchitis virus (IBV) was an major respiratory disease-causing agents that lead to significant losses in birds. Dendritic cells (DCs), an major antigen-presenting cells, influence viruses pathogenicity as well as host immune response. Expression of host non-coding mRNA changes markedly during infectious bronchitis virus (IBV) infection of avian, but their role in regulating host immune function to defend IBV infection has not been explored. Here, microarray, including mRNAs, miRNAs and lncRNAs, were analysed to better understand the interaction between IBV and avian DCs. Results: Firstly, we found that IBV infection can effectively induce avian DCs to become mature. Interestingly, inactivated IBV possess high ability in inducing DC maturation and activating lymphocytes than that in actived IBV stimulated group. Then, result identified that IBV infection induced 1093 upregulated and 845 downregulated mRNAs in avian DCs. Analysis of Gene Ontology suggested that celluar macromolecule and protein location (GO-BP), as well as transcription factor binding (GO-MF) were abundance in IBV infected group. Whilst, pathway analyses suggested that oxidative phosphorylation and T cell receptor signalling pathways might activated in IBV group. Moreover, microRNA (miRNA) and long non-coding RNA (lncRNA) alterations in IBV-stimulated avian DCs were observed. A total of 19 significantly altered (7 up and 12 down) miRNAs and 101 (75 up and 26 down) lncRNAs were identified in IBV-stimulated DCs. Furtherly insight analyses not only gain that regulation of actin cytoskeleton and MAPK signal pathway were contributed to IBV stimulated miRNAs target genes, but also build an regulatory networks based on co-expressed lncRNA and mRNA. Finally, our study identified 2 TF-miRNA (CEBPA-miR1772 and CEBPA-miR21), which we based on to constructed 53 transcription factor (TF)–miRNA–mRNA interactions involving 1 TF, 2 miRNAs, and 53 mRNAs in IBV-stimulated avian DCs.
Project description:Thomas Hunt Morgan and colleagues identified variation in gene copy number in Drosophila in the 1920s and 1930s and linked such variation to phenotypic differences [Bridges, C. B. (1936) Science 83, 210]. Yet the extent of variation in the number of chromosomes, chromosomal regions, or gene copies, and the importance of this variation within species, remain poorly understood. Here, we focus on copy-number variation in Drosophila melanogaster. We characterize copy-number polymorphism (CNP) across genomic regions, and we contrast patterns to infer the evolutionary processes acting on this variation. Copy-number variation in D. melanogaster is non-randomly distributed, presumably due to a mutational bias produced by tandem repeats or other mechanisms. Comparisons of coding and noncoding CNPs, however, reveal a strong effect of purifying selection in the removal of structural variation from functionally constrained regions. Most patterns of CNP in D. melanogaster suggest that negative selection and mutational biases are the primary agents responsible for shaping structural variation. Keywords: comparative genomic hybridization