Arabidopsis thaliana cell suspension cultures (ACSC) were subjected to 30-min, mild chemical treatments with three different singlet oxygen elicitors at low-medium light conditions (150 E m2 s1) with the aim of getting a better understanding of singlet oxygen-mediated defence responses in plants. The three elicitors Indigo Carmine (IC), Methylene Violet (MV) and Rose Bengal (RB) at a concentration of 0.5 M were chosen because they exhibited different abilities to permeate the plasma membrane and to accumulate in the cell soma or organelles such as chloroplasts. In addition, ACSC were treated with 500 M H2O2 for comparison. Confocal image analysis of Arabidopsis cells revealed that IC was not retained in cells, whereas MV and RB permeated the plasma membrane and accumulated in the chloroplast envelope and inside chloroplasts, respectively. As a consequence of their different cellular location, the physiological, transcriptional and photosynthetic responses of Arabidopsis cells to singlet oxygen production varied from each other and the activation of programmed cell death (PCD) was observed in ACSC treated with 0.5 M RB, but not with the other elicitor nor with 500 M H2O2. The role of chloroplasts in the activation of PCD was further investigated when this physiological response was analyzed in dark-grown cell cultures containing undifferentiated plastids. Interestingly, PCD was only activated in light-grown, but not in dark-grown, Arabidopsis cell cultures, suggesting that singlet oxygen-mediated defence responses were initiated inside chloroplasts. Genome-wide transcriptional profile analyses were performed as well and the results proved that there were only statistically significant changes in the transcript expression of light-grown ACSC treated with 0.5 M RB and 500 M H2O2, but not with IC nor with MV. Functional enrichment analyses revealed that GO/Biological process terms associated with defence responses were common in the treatments with 0.5 M RB and 500 M H2O2; however, resistance response to pathogen and PCD terms were only significantly over-represented in the RB treatment. Moreover, the analysis of the up-regulated transcripts in ACSC treated with 0.5 M RB brought out that both specific markers for singlet oxygen from the conditional fluorescence (flu) mutant of Arabidopsis and transcripts with a key role in hormone-activated PCD (i.e. ethylene and jasmonic acid) were present, although there was no evidence for the up-regulation of EDS1 encoding the ENHANCED DISEASE SUSCEPTIBILITY PROTEIN 1. Finally, a co-regulation analysis proved that ACSC treated with 0.5 M RB exhibited higher correlation with the flu family mutants than with other singlet oxygen producer mutants of Arabidopsis or wild-type plants of Arabidopsis subjected to high light treatments, where singlet oxygen was produced in photosystem II and an acclimatory response was activated instead of PCD.
Programmed cell death activated by Rose Bengal in Arabidopsis thaliana cell suspension cultures requires functional chloroplasts.
Treatment
View SamplesWe have investigated the genomic response of Arabidopsis cell suspension culture under high light. Our main goal has been twofold: first, to establish whether chloroplasts in Arabidopsis cell suspension culture are functional and, as such, can act as sensors of adverse external stimuli leading to the activation of genomic defence responses in a manner similar to that described in whole plants exposed to a wide range of environmental stresses and; second, to distinguish which of the ROS that would be probably generated in the chloroplasts is predominant.
Early transcriptional defense responses in Arabidopsis cell suspension culture under high-light conditions.
Disease
View SamplesPseudomonas aeruginosa is an opportunistic pathogen that causes severe health problems. Despite intensive investigation, many aspects of microbial virulence remain poorly understood. We used a high-throughput, high-content, whole-organism, phenotypic screen to identify small molecules that inhibit P. aeruginosa virulence in C. elegans. Approximately half of the hits were known antimicrobials. A large number of hits were non-antimicrobial bioactive compounds, including the cancer chemotherapeutic 5-fluorouracil. We determined that 5-fluorouracil both transiently inhibits bacterial growth and reduces pyoverdine biosynthesis. Pyoverdine is a siderophore that regulates the expression of several virulence determinants and is critical for pathogenesis in mammals. We show that 5-fluorouridine, a downstream metabolite of 5-fluorouracil, is responsible for inhibiting pyoverdine biosynthesis. We also show that 5-fluorouridine, in contrast to 5-fluorouracil, is a genuine anti-virulent compound, with no bacteriostatic or bacteriocidal activity. To our knowledge, this is the first report utilizing a whole-organism screen to identify novel compounds with antivirulent properties effective against P. aeruginosa.
A High-Content, Phenotypic Screen Identifies Fluorouridine as an Inhibitor of Pyoverdine Biosynthesis and Pseudomonas aeruginosa Virulence.
Specimen part, Treatment
View SamplesThe maize inbred line A661 shows a characteristic phenotype when grown at suboptimal temperatures for three weeks and then is exposed to optimal temperatures for one extra week. After this period the third leaf showed two well defined sections: distal (chlorophyll-less; CL) and proximal (chlorophyll-containing; CC) sections. To further investigate the performance of the inbred line A661 under cold conditions a gene expression profiling analysis was conducted using large scale maize microarrays. A total of 1002 transcripts change their expression between both leaf sections and the majority of these codify for proteins located to the chloroplast.
Genetic regulation of cold-induced albinism in the maize inbred line A661.
No sample metadata fields
View SamplesThe study recapitulates, through in vitro micropatterned co-cultures, interactions between HIV-infected T-lymphocytes and intestinal epithelial cells in order to investigate the mechanisms underlying the disruption of normal epithelial cell and barrier function during HIV infection. The co-culture method simplifies observation/monitoring of the two cell types and is particularly suited for laser microdissection-based retrieval of the epithelial cells for downstream gene expressions studies.
Micropatterned co-cultures of T-lymphocytes and epithelial cells as a model of mucosal immune system.
Specimen part, Cell line, Treatment
View SamplesStem and progenitor cells are the critical units for tissue maintenance, regeneration, and repair. The activation of regenerative events in response to tissue injury has been correlated with mobilization of tissue-resident progenitor cells, which is functional to the wound healing process. However, until now there has been no evidence for the presence of cells with a healing capacity circulating in healthy conditions. We identified a rare cell population present in the peripheral blood of healthy mice that actively participates in tissue repair. These Circulating cells, with a Homing ability and involved in the Healing process (CH cells), were identified by an innovative flowcytometry strategy as small cells not expressing CD45 and lineage markers. Their transcriptome profile revealed that CH cells are unique and present a high expression of key pluripotency- and epiblast-associated genes. More importantly, CH-labeled cells derived from healthy Red Fluorescent Protein (RFP)-transgenic mice and systemically injected into syngeneic fractured wild-type mice migrated and engrafted in wounded tissues, ultimately differentiating into tissue-specific cells. Accordingly, the number of CH cells in the peripheral blood rapidly decreased following femoral fracture. These findings uncover the existence of constitutively circulating cells that may represent novel, accessible, and versatile effectors of therapeutic tissue regeneration.
Identification of a New Cell Population Constitutively Circulating in Healthy Conditions and Endowed with a Homing Ability Toward Injured Sites.
Sex, Specimen part
View SamplesWe report a method for deriving oligodendrocyte lineage cells from human pluripotent stem cells (hPSCs) in three-dimensional (3D) culture called human oligodendrocyte spheroids (hOLS). To characterize oligodendrocyte-lineage cells in hOLS, we isolated O4+ cells by immunopanning and performed deep single cell RNA sequencing. We sequenced 295 cells and compared their profiles to unsorted cells isolated from primary human fetal cortex, primary human adult cortex, and hCS. Clustering of all cells using the t-distributed stochastic neighbor embedding (tSNE) approach revealed a distinct populations of SOX10+ oligodendrocytes, within which the O4+ cells derived from hOLS clustered most closely to oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes from the primary human adult cortical tissue. Additionally, subpopulations of OPCs, newly formed oligodendrocytes, and myelinating oligodendrocytes derived were observed in the hOLS-derived cluster. To further assess the state of oligodendrocyte-lineage cells in hOLS, we performed a Monocle analysis which revealed a spectrum of oligodendrocyte-lineage stages in hOLS ranging from dividing cells that closely resembled primary OPCs to mature cells that closely resembled primary oligodendrocytes. Overall design: Examination of gene expression in single oligodendrocyte-lineage cells derived from human pluripotent stem cells in three-dimensional culture
Differentiation and maturation of oligodendrocytes in human three-dimensional neural cultures.
Subject
View SamplesExpression profiling of sheep born to Australian industry sires with high and low genetic merit (Estimated Breeding Values or EBVs) for eye muscle depth (EMD). Progeny (40) from six Poll Dorset sires representing well defined extremes of EBVs for Eye Muscle Depth (low EBV EMD and high EBV EMD) were selected for analysis. The six sires were Australian industry sires with three sires representative of low EBV EMD and three representing high EBV EMD.
An Always Correlated gene expression landscape for ovine skeletal muscle, lessons learnt from comparison with an "equivalent" bovine landscape.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Progression from low- to high-grade in a glioblastoma model reveals the pivotal role of immunoediting.
Specimen part
View SamplesAtaxin 1 (Atxn1) is a protein of unknown function associated with cerebellar neurodegeneration in spinocerebellar ataxia type 1 (SCA1). SCA1 is caused by an expanded polyglutamine within Atxn1 by gain-of-function mechanisms. Lack of Atxn1 in mice triggers motor deficits in the absence of neurodegeneration or apparent neuropathological abnormalities.We extracted RNA from cerebellum of 5 Atxn1-null mice and 5 WT. Cerebellar gene expression profiles at 15 weeks of age were generated usSCA1 ing Affymetrix MOE430A arrays. Identifying the molecular pathways regulated by Atxn1 can provide insights into the early molecular mechanisms underlying neuronal dysfunction.
Down-regulation of the dopamine receptor D2 in mice lacking ataxin 1.
Age, Specimen part
View Samples