Background Small colony variants (SCVs) are slow-growing bacteria, which often show increased resistance to antibiotics and cause latent or recurrent infections. It is therefore important to understand the mechanisms at the basis of this phenotypic switch. Methodology/Principal findings One SCV (termed PAO-SCV) was isolated, showing high resistance to gentamicin and to the cephalosporine cefotaxime. PAO-SCV was prone to reversion as evidenced by emergence of large colonies with a frequency of 10-5 on media without antibiotics while it was stably maintained in presence of gentamicin. PAO-SCV showed a delayed growth, defective motility, and strongly reduced levels of the quorum sensing Pseudomonas quinolone signal (PQS). Whole genome expression analysis further suggested a multi-layered antibiotic resistance mechanism, including simultaneous over-expression of two drug efflux pumps (MexAB-OprM, MexXY-OprM), the LPS modification operon arnBCADTEF, and the PhoP-PhoQ two-component system. Conversely, the genes for the synthesis of PQS were strongly down-regulated in PAOSCV. Finally, genomic analysis revealed the presence of mutations in phoP and phoQ genes as well as in the mexZ gene encoding a repressor of the mexXY and mexABoprM genes. Only one mutation occurred only in REV, at nucleotide 1020 of the tufA gene, a paralog of tufB, both encoding the elongation factor Tu, causing a change of the rarely used aspartic acid codon GAU to the more common GAC, possibly causing an increase of tufA mRNA translation. High expression of phoP and phoQ was confirmed for the SCV variant while the revertant showed expression levels reduced to wild-type levels. Conclusions By combining data coming from phenotypic, gene expression and proteome analysis, we could demonstrate that resistance to aminoglycosides in one SCV mutant is multifactorial including overexpression of efflux mechanisms, LPS modification and is accompanied by a drastic down-regulation of the Pseudomonas quinolone signal quorum sensing system.
Phenotypic and genome-wide analysis of an antibiotic-resistant small colony variant (SCV) of Pseudomonas aeruginosa.
No sample metadata fields
View SamplesAn essential step for understanding the transcriptional circuits that control development and physiology is the global identification and characterization of regulatory elements. Here we present the first map of regulatory elements across the development and ageing of an animal, identifying 42,245 elements accessible in at least one C. elegans stage. Based on nuclear transcription profiles, we define 15,918 protein-coding promoters and 17,918 putative enhancers, and find that both types of element can drive orientation-independent transcription. Additionally, hundreds of promoters produce transcripts antisense to protein coding genes, suggesting involvement in a widespread regulatory mechanism. We find that the accessibility of most elements is regulated during development and/or ageing and that patterns of accessibility change are linked to specific developmental or physiological processes. The map and characterization of regulatory elements across C. elegans life provides a platform for understanding how transcription controls development and ageing. Overall design: Capped nuclear RNA-seq of wild-type and glp-1 was performed to monitor transcription elongation across C. elegans development and ageing. Two biological replicates were done for each time point (six developmental stages and five ageing timepoints).
Chromatin accessibility dynamics across <i>C. elegans</i> development and ageing.
Cell line, Subject
View SamplesType II testicular germ cell cancers (GCC) are the most frequently diagnosed tumors in young men (20 - 40 years) and are classified as seminoma or non-seminoma. GCCs are commonly treated by orchiectomy and chemo- or radiotherapy. However, a subset of metastatic non-seminomas display only incomplete remission or relapse and require novel treatment options. Recent studies have shown effective application of the small-molecule inhibitor JQ1 in tumor therapy, which interferes with the function of bromodomain and extra-terminal (BET)-proteins. Here, we demonstrate that upon JQ1 doses 250 nM GCC cell lines and Sertoli cells display compromised survival and induction of cell cycle arrest. JQ1 treated GCC cell lines display upregulation of genes indicative for DNA damage and a cellular stress response. Additionally, downregulation of pluripotency factors and induction of mesodermal differentiation was detected. GCCs xenografted in vivo showed a reduction in tumor size, proliferation and angiogenesis when subjected to JQ1 treatment. The combination of JQ1 and the histone deacetylase inhibitor romidepsin further enhanced the apoptotic effect in vitro and in vivo. Thus, we propose that JQ1 alone, or in combination with romidepsin may serve as a novel therapeutic option for GCCs.
The bromodomain inhibitor JQ1 triggers growth arrest and apoptosis in testicular germ cell tumours in vitro and in vivo.
Specimen part, Cell line, Time
View SamplesMaintenance and maturation of primordial germ cells is controlled by complex genetic and epigenetic cascades, and disturbances in this network lead to either infertility or malignant aberration. Transcription factor Tcfap2c / TFAP2C has been described to be essential for primordial germ cell maintenance and to be upregulated in several human germ cell cancers. Using global gene expression profiling, we identified genes deregulated upon loss of Tcfap2c in primordial germ cell-like cells. We show that loss of Tcfap2c affects many aspects of the genetic network regulating germ cell biology, such as downregulation maturation markers and induction of markers indicative of somatic differentiation, cell cycle, epigenetic remodeling, and pluripotency associated genes. Chromatin-immunoprecipitation analyses demonstrated binding of Tcfap2c to regulatory regions of deregulated genes (Sfrp1, Dmrt1, Nanos3, c-Kit, Cdk6, Cdkn1a, Fgf4, Klf4, Dnmt3b and Dnmt3l) suggesting that these genes are direct transcriptional targets of Tcfap2c in primordial germ cells. Since Tcfap2c deficient primordial germ cell like cells display cancer related deregulations in epigenetic remodeling, cell cycle and pluripotency control, the Tcfap2c-knockout allele was bred onto 129S2/Sv genetic background. There, mice heterozygous for Tcfap2c develop germ cell cancer with high incidence. Precursor lesions can be observed as early as E16.5 in developing testes displaying persisting expression of pluripotency markers. We further demonstrate, that mice with a heterozygous deletion of the Tcfap2c target gene Nanos3 are also prone to develop teratoma. These data highlight Tcfap2c as a critical and dose-sensitive regulator of germ cell fate.
Transcription factor TFAP2C regulates major programs required for murine fetal germ cell maintenance and haploinsufficiency predisposes to teratomas in male mice.
Specimen part
View SamplesTranscriptomes of differentiated cells of the conditionally immortalized mouse podocyte cell line SVI (Schiwek et al., Kidney Int. 66: 91-101, 2004) were determined as described in Warsow et al. (Kidney Int. 84: 104-115, 2013) after application of mechanical stress (Endlich et al., J. Am. Soc. Nephrol. 12: 413-422, 2001) as compared to control conditions.
Mechanical stress enhances CD9 expression in cultured podocytes.
Specimen part, Cell line
View SamplesThe vascular endothelial growth factor A (VEGF) is involved in various physiological processes such as angiogenesis or wound healing but is also crucial in pathological events such as tumor growth. Thus, clinical anti-VEGF treatments have been developed which could already prove to have enormous beneficial effects for cancer patients. In this article we describe the first VEGF-derived CD8+ T-cell epitope. The natural HLA ligand SRFGGAVVR was identified by differential mass spectrometry in two primary renal cell carcinomas (RCC) and was significantly over-presented on both tumor tissues. SRFGGAVVR is derived from a cryptic translated region of VEGF presumably by initiation of translation at the non-classical start codon CUG499. SRFGGAVVR specific T-cells were generated in vitro using peptide loaded dendritic cells or artificial antigen presenting cells. They were identified by HLA tetramer analysis after in vitro stimulation. SRFGGAVVR specific CD8+ T-cells were fully functional T-effector cells, which were able to secrete IFN-gamma upon stimulation and killed tumor cells in vitro. Additionally, we have quantitatively analyzed VEGF mRNA and protein levels in RCC tumor and normal tissue samples by gene chip analysis, qRT-PCR, in situ hybridization, and bead based immuno assay. In the future, T-cells directed against VEGF as a tumor associated antigen may represent a possible way of combining peptide-based anti-VEGF immunotherapy with already existent anti-VEGF cancer therapies.
A cryptic vascular endothelial growth factor T-cell epitope: identification and characterization by mass spectrometry and T-cell assays.
No sample metadata fields
View SamplesJoMa1 cells are pluripotent precursor cells, derived from the neural crest of mice transgenic for tamoxifen-inducible c-Myc. Following transfection with a cDNA encoding for MYCN, cells become immortlized even in the absence of tamoxifen.
MYCN and ALKF1174L are sufficient to drive neuroblastoma development from neural crest progenitor cells.
Specimen part, Cell line
View SamplesAnalysis of TH17 cells redirected with chimeric antigen receptors (CAR) expressing various signaling domains (including CD28, 4-1BB and ICOS) after surrogate antigen stimulation.
ICOS-based chimeric antigen receptors program bipolar TH17/TH1 cells.
Specimen part, Time
View SamplesThe protease activity of the paracaspase MALT1 plays an important role in antigen receptor-mediated lymphocyte activation by controlling the activity of the transcription factor NF-kB and is thus essential for the expression of inflammatory target genes.
MALT1 Protease Activity Controls the Expression of Inflammatory Genes in Keratinocytes upon Zymosan Stimulation.
Treatment
View SamplesWe analyzed gene expression profiles of IL-18 generated murine NK cells in comparison to unstimulated, freshly isolated splenic NK cells.
Immunoregulatory natural killer cells suppress autoimmunity by down-regulating antigen-specific CD8+ T cells in mice.
Specimen part, Treatment
View Samples