Project description:We sought to determine how a cystic fibrosis isolate of Stenotrophomonas maltophilia responds to relevant pH gradients (pH 5, 7, and 9) by growing the bacterium in phosphate buffered media and conducting RNAseq experiments. Our data suggests acidic conditions are stressful for strain FLR19, as it responded by increasing expression of stress-response and antibiotic-resistance genes.
Project description:Stenotrophomonas maltophilia is an important opportunistic pathogen affecting primarily hospitalized and immuno-compromised hosts. We constructed an hfq deletion mutant (Delta-hfq) of S. maltophilia, and compared the behaviour of wild-type and Delta-hfq S. maltophilia cells in a variety of assays. Differential RNA sequencing analysis (dRNA-seq) of RNA isolated from S. maltophilia wild-type and Delta-hfq strains showed that Hfq regulates expression of genes encoding flagellar and fimbrial components, transmembrane proteins, as well as enzymes involved in different metabolic pathways. Moreover, we analysed expression of several sRNAs identified by dRNA-seq in wild-type. The accumulation of two sRNAs was strongly reduced in the absence of Hfq. TEX (terminator exonuclease) treated and untreated libraries of the wild type and the Delta-hfq mutant were sequenced and compared
Project description:We calculated half-life values of mRNAs quantified by RNA-Seq by a suitable method of normalization. We determined the half-lives of more than 2200 mRNAs in the Stenotrophomonas maltophilia D457 wild-type strain and in an isogenic RNase G deficient mutant. Median half-lives were 2,74 and 3 min in the wild-type and the rng-deficient mutant respectively. We found an overall enhancement of half-life times of mRNAs when the gene encoding RNase G is lacking, showing that many RNAs are targets of RNase G in S. maltophilia. For achieving such goal, we propose a method for the normalization of RNA-Seq based studies on global bacterial mRNA decay.
Project description:The goal of this study was to elucidate genes that are employed by the bacterivorous nematode Caenorhabditis elegans to respond to the emerging nosocomial bacterial pathogen Stenotrophomonas maltophilia.
Project description:Stenotrophomonas maltophilia is an important opportunistic pathogen affecting primarily hospitalized and immuno-compromised hosts. We constructed an hfq deletion mutant (Delta-hfq) of S. maltophilia, and compared the behaviour of wild-type and Delta-hfq S. maltophilia cells in a variety of assays. Differential RNA sequencing analysis (dRNA-seq) of RNA isolated from S. maltophilia wild-type and Delta-hfq strains showed that Hfq regulates expression of genes encoding flagellar and fimbrial components, transmembrane proteins, as well as enzymes involved in different metabolic pathways. Moreover, we analysed expression of several sRNAs identified by dRNA-seq in wild-type. The accumulation of two sRNAs was strongly reduced in the absence of Hfq.
Project description:Stenotrophomonas maltophilia is an emerging multidrug resistance opportunistic pathogen affecting immunocompromised and hospitalized patients. S. maltophilia is an environmental bacterium which adapts to human body and causing infection. S. rhizophilia, a non-pathogenic and phylogenetic neighbour of S. maltophilia is unable to grow at human body temperature. Thus, to understand molecular mechanism underlying the adaptation of S. maltophilia at human body temperature, we performed the comparative transcriptome analysis of S.maltophilia at 28 °C (representative for the environmental niches) and 37 °C (representative for human body) by using RNA-Seq. The major temperature-induced genes include genes for Type IV secretion system, aerotaxis, and cation diffusion facilitator family transporter suggesting its potential role in the adaptation and virulence of S. maltophilia. The downregulated genes at 37 °C includes the genes for the cell motility, energy generation and metabolism, lipid metabolism, translation, amino acid metabolism and transport, replication and repair, inorganic ion and transport metabolism lipid metabolism, coenzyme metabolism.
Project description:Stenotrophomonas maltophilia is an emerging opportunistic multidrug-resistant pathogen frequently co-isolated with other relevant nosocomial pathogens in respiratory tract infections. S. maltophilia uses the endogenous DSF quorum sensing (QS) system to regulate virulence processes but can also respond to exogenous AHL signals produced by neighboring bacteria. A whole-transcriptome sequencing analysis was performed for S. maltophilia strain K279a in the exponential and stationary phases and in exponential cultures after a treatment with exogenous DSF or AHLs. Among the common top upregulated genes, the putative TetR-like regulator Smlt2053 was selected for functional characterization. This regulator was found to sense long-chain fatty acids, including the QS signal DSF, and activate a β-oxidation catabolic pathway.
Project description:Stenotrophomonas maltophilia K279a diverges into subpopulations with distinct but reversible phenotypes of small and big colonies when challenged with ampicillin. This observation is consistent with the formation of long cell chains during exponential growth phase and the occurrence of mainly coccoid– or rod-shaped cells in liquid media. Further, scanning electron micrographs of SMK279a revealed that cells formed gigantic outer membrane vesicles in response to β-lactam treatment. RNA-seq analysis of small vs. big colonies unveiled that cells regulate at least seven genes differentially among colony morphotypes. Among those were the blaL1 and blaL2 genes the most strongly regulated ones with an eleven- and six-fold increased transcription, respectively. Further studies with promoter fusions of blaL1 and blaL2 genes implied that expression of both genes is also subject to high levels of phenotypic heterogeneous expression on a single cell level. Additional RNA-seq analysis of this homogenously versus heterogeneously blaL2 expressing cells identified comE homologue as differentially expressed, in which by the expression of extra copies of comE in S. maltophilia K279a reduced the level of those cells that were in a blaL2-ON model to 1% or lower. Together with genome-wide sequence analysis of cells from the different colony morphotypes, the data presented here suggests that phenotypic heterogeneity in S. maltophilia K279a is a result of non-genetic variations within isogenic populations and also polymorphisms in this strain do not influence β-lactamase resistance phenotype.