Project description:To gain deeper insights into antibacterial mechanisms of NAD+ and bacterial adaptation, we generated and sequenced NAD+ resistant clones of Spn. For this purpose, Spn was cultivated in liquid medium with increasing concentrations (50 µM to 5 mM) of NAD+. After six passages, bacteria were plated on blood agar supplemented with 500 µM NAD+ and three clones were picked
Project description:Germline-specific RNA helicase Spindle-E (Spn-E) is known to be essential for piRNA silencing in Drosophila that takes place mainly in the perinuclear nuage granules. Loss-of-function spn-E mutations lead to tandem Stellate genes derepression in the testes and retrotransposon mobilization in the ovaries. However, Spn-E functions in the piRNA pathway are still obscure. Analysis of total library of short RNAs from the testes of spn-E heterozygous flies revealed the presence of abundant piRNA ping-pong pairs originating from Su(Ste) transcripts. The abundance of these ping-pong pairs were sharply reduced in the library from the testes of spn-E mutants. Thus we found that ping-pong mechanism contributed to Su(Ste) piRNA generation in the testes. The lack of Spn-E caused a significant drop of protein levels of key ping-pong participants, Aubergine (Aub) and AGO3 proteins of PIWI subfamily, in the germline of both males and females, but did not disrupt of their assembly in nuage granules. We found that observed decline of the protein expression was not caused by suppression of aub and ago3 transcription as well as total transcription, indicating possible contribution of Spn-E to post-transcriptional regulation.
Project description:rasiRNA (rasiRNAs, repeat-associated short interfering RNAs) system is a mechanism of silencing of mobile element transpositions in germline of a number of species including Drosophila melanogaster. rasiRNA itself is a short RNAs which participate in transposon transcription repression and mRNA degradation. Defects in rasiRNA system lead to increased transposition rate and developmental abnormalities due to accumulation of double-strand DNA breaks in fruitfly testes and ovaries. A number of proteins participate in rasiRNA-mediated repression including SPN-E (homeless), PIWI and ARMI. Mutations in the genes of these proteins lead to significant mobile element mRNA accumulation. We performed microarray-based study of effects of spn-E mutation on expression in fruitfly ovaries - one of the organs where rasiRNA system work. Our goal was the identification of other (besides mobile elements) targets of rasiRNA system regulation Total RNA samples, extracted from ovaries of spn-E1/spn-Ehls03987 trans-heterozygotes and mix of heterozygotes spn-E1/TM3 and spn-Ehls03987/TM3 (spn-E/+ hereafter), were reverse transcribed, IVT-amplified and labeled with Cy3 or Cy5. Mix of differently labeled aRNAs (spn-E1/spn-Ehls03987 - target, spn-E/+ - reference) was hybridized to Oligo14Kv2 microarray slides (CDMC), washed, scanned and treated in GenePix 6 (Molecular Devices) and subsequently in FlexArray 1.6.1.1 (McGill University and GM-CM-)nome QuM-CM-)bec Innovation Centre). Three biological replica (one sample dye-swapped) were produced and analyzed.
Project description:Streptococcus pneumoniae (Spn) is a major causative organism of empyema, an inflammatory condition occurring in the pleural sac. In this study, we used Spn cDNA microarrays to characterize the transcriptional responses occurring during initial contact between Spn and a human pleural mesothelial cell line (PMC) in vitro
Project description:Solid-pseudopapillary neoplasm of pancreas(SPN), ductal adenocarcinoma(PCA), neuroendocrine tumor(NET) and non-neoplastic pancreas. To investigate the specific gene expression of SPN compared to other types of pancreatic tumor, we analyzed large-scale gene expressioin analysis to identify the molecular signature that may affect SPN tumorigenesis. Differentially expressed genes were analyzed on SPNs, PCAs, NETs and Non-neoplastic tissues. Solid-pseudopapillary neoplasm (SPN) is an uncommon pancreatic tumor with distinct clinicopathologic features. SPNs are characterized by mutations in exon 3 of CTNNB1. However, little is known about the gene and microRNA expression profiles of SPNs. Thus, we sought to characterize SPN-specific gene expression and identify the signaling pathways activated in these tumors. The mRNA expression profile of 14 SPNs, 6 pancreatic adenocarcinomas (PCAs), 6 pancreatic neuroendocrine tumors (NETs), and five non-neoplastic pancreatic tissues were analyzed.
Project description:Solid-pseudopapillary neoplasm of pancreas (SPN), ductal adenocarcinoma (PCA), neuroendocrine tumor (NET) and non-neoplastic pancreas. comparison with gene expression of tumors and non-tumors To investigate the specific microRNA expression of SPN compared to other types of pancreatic tumor, we analyzed large-scale microRNA expressioin analysis to identify the molecular signature that may affect SPN tumorigenesis with mRNA expression profiles. Differentially expressed microRNAs were analyzed on SPNs, PCAs, NETs and Non-neoplastic tissues.
Project description:Solid-pseudopapillary neoplasm of pancreas(SPN), ductal adenocarcinoma(PCA), neuroendocrine tumor(NET) and non-neoplastic pancreas. To investigate the specific gene expression of SPN compared to other types of pancreatic tumor, we analyzed large-scale gene expressioin analysis to identify the molecular signature that may affect SPN tumorigenesis. Differentially expressed genes were analyzed on SPNs, PCAs, NETs and Non-neoplastic tissues.
Project description:Secondary bacterial pneumonia following influenza infection is a significant cause of mortality worldwide. Upper respiratory tract pneumococcal carriage is important as both determinants of disease and population transmission. The immunological mechanisms that contain pneumococcal carriage are well-studied in mice but remain unclear in humans. Loss of this control of carriage following influenza infection is associated with secondary bacterial pneumonia during seasonal and pandemic outbreaks. We used a human type 6B pneumococcal challenge model to show that carriage acquisition induces early degranulation of resident neutrophils and recruitment of monocytes to the nose. Monocyte function associated with clearance of pneumococcal carriage. Prior nasal infection with live attenuated influenza virus induced inflammation, impaired innate function and altered genome-wide nasal gene responses to pneumococcal carriage. Levels of the cytokine IP-10 promoted by viral infection at the time of pneumococcal encounter was positively associated with bacterial density. These findings provide novel insights in nasal immunity to pneumococcus and viral-bacterial interactions during co-infection.
Project description:The objectives of the study were to examine the gene expression profile of human pleural mesothelial cells following infection with Streptococcus pneumoniae. The abstract is as follows: Streptococcus pneumoniae (Spn) is a major causative organism of empyema, an inflammatory condition occurring in the pleural sac. In this study, we used human and Spn cDNA microarrays to characterize the transcriptional responses occurring during initial contact between Spn and a human pleural mesothelial cell line (PMC) in vitro. Using stringent filtering criteria, 42 and 23 Spn genes were up-and down-regulated respectively. In particular, genes encoding factors potentially involved in metabolic processes and Spn adherence to eukaryotic cells were up-regulated e.g. glnQ, glnA, aliA, PsaB, LytB and nox. After Spn initial contact, 870 human genes were differentially regulated and the largest numbers of significant gene expression changes were found in canonical pathways for eukaryotic initiation factor 2 signaling (60 genes out of 171), oxidative phosphorylation (32/103), mitochondrial dysfunction (37/164), eIF4 and p70S6K signaling (28/142), mTOR signaling (27/182), NRF2-mediated oxidative stress response (20/177), epithelial adherens junction remodeling (11/66) and ubiquitination (22/254). The cellular response appeared to be directed towards host cell survival and defense. Spn did not activate NF-kB or phosphorylate p38 MAPK or induce cytokine production. Moreover, Spn infection of TNF-α pre-stimulated PMC inhibited production of IL-6 and IL-8 secretion by >50% (p<0.01). In summary, his descriptive study provides datasets and a platform for examining further the molecular mechanisms underlying the pathogenesis of empyema.
Project description:We used genome-wide transcriptional profiling by microarray to assess the contribution of pneumolysin on macrophage innate immune responses to the TIGR4 strain of Streptococcus pneumoniae (Spn). We focused on the early transcriptional responses at 4 hours after inoculation of human blood monocyte-derived macrophage cultures with Spn at a multiplicity of 10 bacteria to each cell. We compared transcriptomes in the presence and absence of wildtype or pneumolysin-deficient TIGR4 Spn, and also in the presence and absence of cytochalasin D to assess whether there is a differential effect of pneumolysin on innate immune responses with and without bacterial internalisation.