Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Secretion stress caused by overexpression of heterologous α-amylase in Bacillus subtilis

ABSTRACT: Transcriptome analysis was used to investigate the global stress response of the Gram-positive bacterium Bacillus subtilis caused by overproduction of the well-secreted AmyQ α-amylase from Bacillus amyloliquefaciens. Analyses of the control and overproducing strains were carried out at the end of exponential growth and in stationary phase, when protein secretion from B. subtilis is optimal. Among the genes that showed increased expression were htrA and htrB, which are part of the CssRS regulon that responds to high-level protein secretion and heat stress. The analysis of the transcriptome profiles of a cssS mutant compared to the wild-type, under identical secretion stress conditions, revealed several genes with altered transcription in a CssRS-dependent manner, for example citM, ylxF, yloA, ykoJ and several genes of the flgB operon. However, a high affinity CssR-binding was only observed for htrA and htrB, and possibly for citM. In addition, the DNA macroarray approach reveal that several genes of the sporulation pathway are downregulated by AmyQ overexpression, and a group of motility-specific (σD-dependent) transcripts were clearly upregulated. Subsequent flow cytometric analyses demonstrate that upon overproduction of AmyQ as well as a non-secretable variant of the α-amylase, the process of sporulation is severely inhibited. The same experiments were implemented to investigate the expression levels of the hag promoter, a well-established reporter for σD-dependent gene expression. This approach confirmed the observations based on our DNA macroarray analyses and led us to conclude that expression levels of several genes involved in motility are maintained at high levels under all conditions of α-amylase overproduction. Secretion stress was applied by overproducing the well-secreted AmyQ α-amylase (pKTH10 vector) from B. amyloliquefaciens. Besides examining secretion stress in wild-type cells, we compared transcriptome profiles of a cssS mutant strain under conditions of high-level AmyQ production. Samples for transcriptome analyses were collected at the late exponential growth stage (one hour before the transition point) and 3 hours upon entry in the stationary growth phase. Three independent cultures of each strain were used and cells were sampled for macroarray experiments. Duplicate spots were averaged in Array-Pro software (Media Cybernetics, Inc.) and the signal was normalized after background subtraction by calculation of the percentage of total signal per gene using Microsoft Excel.

ORGANISM(S): Bacillus subtilis subsp. subtilis str. 168

SUBMITTER: Andrzej Lulko

PROVIDER: E-GEOD-8014 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Publications

Production and secretion stress caused by overexpression of heterologous alpha-amylase leads to inhibition of sporulation and a prolonged motile phase in Bacillus subtilis.

Lulko Andrzej T AT Veening Jan-Willem JW Buist Girbe G Smits Wiep Klaas WK Blom Evert Jan EJ Beekman Aaron C AC Bron Sierd S Kuipers Oscar P OP

Applied and environmental microbiology 20070622 16

Transcriptome analysis was used to investigate the global stress response of the gram-positive bacterium Bacillus subtilis caused by overproduction of the well-secreted AmyQ alpha-amylase from Bacillus amyloliquefaciens. Analyses of the control and overproducing strains were carried out at the end of exponential growth and in stationary phase, when protein secretion from B. subtilis is optimal. Among the genes that showed increased expression were htrA and htrB, which are part of the CssRS regul ...[more]

PMID: 17586671

Similar Datasets

Project description:An NF-κB target gene array (Panomics, Inc., Redwood City, CA) was performed to profile the PAO1-dependent expression pattern of 111 NF-kB-regulated genes in primary human airway epithelial cells (HAECs). A small scale microarray was carried out using NF-κB target gene array kit (Panomics, Inc., Redwood City, CA). A long sense-strand oligonucleotide for each of the 111 human genes that have been previously shown to be regulated by NF-KB signaling pathway was spotted in duplicate on the nitrocellulose membrane. Biotinylated DNA was spotted along the right and bottom sides of the array membrane as control. The arrays were performed according to the manufacturer’s instructions. In brief, HAECs were stimulated for 18 hours with the heat-killed bacteria PAO1 (multiplicity of infection: 100:1). Control experiment used PBS instead of bacteria. mRNA of HAECs was isolated using biotin-labeled oligo(dT)20 and streptavidin-conjugated magnetic particles (Roche, Germany). 500 ng mRNA was used to prepare biotin-labeled cDNA probes through incorporation of biotin-dUTP into cDNA via reverse transcription reactions. Each biotin-labeled cDNA probe was hybridized to an array membrane at 42°C overnight in a hybridization incubator (Fisher Scientific, Pittsburgh, PA). The membrane was washed and subjected to further incubations with blocking buffer and subsequent streptavidin-conjugated HRP. The membrane was developed through chemiluminescence reactions and detected immediately by 1 min exposure to Hyperfilm ECL X-ray films (Amersham, Piscataway, NJ). The dots on the array were quantified through densitometric analysis using GeneTools (Syngene, Frederick, MD) and the value of each dot was determined as D = (signal value – background value)/mean value of biotinylated DNA dots. Ratio (Dbacteria: Dcontrol) was used to determine the effect of bacteria stimulation on the gene regulation. Ratio>1 indicated an up-regulation of the gene. The experiments include two samples, one PBS control sample and one PAO1-stimulated sample.

Project description:Prostaglandin E2 (PGE2) is involved in several inflammatory conditions including periodontitis. The aim of this study was to investigate the global gene expression profile of tumor necrosis factor alpha (TNFalpha) stimulated human gingival fibroblasts, focusing on signal pathways related to PGE2 production and the new PGE2-synthesizing enzymes, prostaglandin E synthases (PGES). The expression of microsomal prostaglandin E synthase-1 (mPGES-1) as well as the upstream cyclooxygenase-2 (COX-2) was up-regulated by TNFalpha, accompanied by increased PGE2 production. In contrast, the expression of microsomal prostaglandin E synthase-2 (mPGES-2) and cytosolic prostaglandin E synthase (cPGES) was unaffected by TNFalpha. Using microarray analysis in a time-course factorial design including time points 1, 3 and 6 h, we identified differentially expressed genes in response to TNFalpha treatment. Enrichment analysis of microarray data identified two positively regulated signal transduction pathways: c-Jun N-terminal kinase (JNK) and Nuclear Factor-kappaB (NF-kappaB). We used specific inhibitors and phosphorylation analysis to confirm their role in PGE2 regulation. Both JNK and NF-kappaB inhibitors reduced the TNFalpha-stimulated up-regulation of mPGES-1 and COX-2 as well as subsequent PGE2 production. The novel finding that TNFalpha-stimulated mPGES-1 is regulated by JNK suggests this kinase as a potential future target for treatment strategies in inflammatory disorders, including periodontitis. Keywords: Time course, gene expression, factorial design. Three human gingival fibroblast cell lines were established from gingival biopsies obtained from 3 healthy patients, 3 to 12 years of age, with no clinical signs of periodontal disease. Cells were incubated with or without TNF-alpha (20 ng/ml) for 1, 3 or 6h. After incubation for 1, 3 or 6 h in the two conditions, the cells were immediately frozen in liquid nitrogen and then stored at -70°C for subsequent isolation of total RNA. The experimental design of the microarray study was set up as a time-course factorial design, to best observe the TNF-alpha induced gene expression changes over time. C++ program (G.F. Glonek, P.J. Solomon, Factorial and time course designs for cDNA microarray experiments, Biostatistics 5 (2004) 89-111) was used to determine the exact layout of the design in order to estimate the interaction effect between treatment and time, i.e. genes that are differentially expressed over time, with optimal statistical efficiency. Cyanine 5 and cyanine 3 were used for labeling. For each cell line 12 hybridizations were performed in a time-course factorial design. In total, 36 hybridizations were performed.

Project description:Streptococcus gordonii, an important primary colonizer of dental plaque biofilm, specifically binds to salivary amylase via the surface-associated amylase-binding protein A (AbpA). We hypothesized that amylase binding to S. gordonii modulates expression of chromosomal genes, which could influence bacterial survival and persistence in the oral cavity. Gene expression profiling by microarray analysis was performed to detect differentially expressed genes in S. gordonii strain CH1 in response to the binding of purified human salivary amylase as compared to exposure to heat-denatured amylase. Selected genes found to be differentially expressed were validated by qRT-PCR. Five genes from the fatty acid synthesis (FAS) cluster were highly (10-35 fold) up-regulated in amylase treated S. gordonii CH1 cells compared to the denatured-amylase treated cells. An abpA-deficient strain of S. gordonii exposed to amylase did not show a similar response in FAS gene expression as observed in the parental strain. Predicted phenotypic effects of amylase binding to S. gordonii strain CH1 associated with increased expression of FAS genes leading to changes in fatty acid synthesis were noted, as evidenced by increased bacterial growth, survival at low pH, and resistance to triclosan. These changes were not observed in the amylase exposed abpA-deficient strain, suggesting for the role of AbpA in amylase-induced phenotype. These results provide evidence that the binding of salivary amylase elicits a differential gene response in S. gordonii, resulting in a phenotype adjustment that is potentially advantageous for bacterial survival in the oral environment. In order to identify amylase-regulated genes, S. gordonii CH1 was grown statically in 40 ml CDM at 37°C in a candle jar to mid-log phase corresponding to an optical density at 600 nm of 0.5 to 0.6.The mid-log phase bacterial culture was divided into two aliquots of equal volume. Bacterial cells from all aliquots were pelleted by centrifugation at 6,000 x g in a Sorvall RC6 centrifuge at 20°C, and washed once with simulated salivary buffer preconditioned to 37°C. Simulated salivary buffer containing 0.4 mg/ml purified, non-glycosylated salivary amylase (native amylase) and preconditioned to 37°C was added to the cells of the fist aliquot; to the cells of the second aliquot simulated salivary buffer containing 0.4 mg/ml of the same salivary amylase denatured by heating to 100°C {Heinen, 1976} and cooled to 37°C was added, as a negative control. Each aliquot, amylase treated and control, was incubated statically for 15 min at 37°C in a candle jar. Total RNA was immediately isolated by the hot acid phenol method as described previously {Vickerman, 2007}, followed by treatment with TurboDNase (Applied Biosystems/Ambion, Austin, TX) according to manufacturer’s protocol. Remaining contaminants were removed using the RNeasy minikit column (Qiagen, Valencia, CA) with the cleanup protocol. Total RNA was quantified using the Nanodrop 2000 spectrophotometer and RNA integrity determined by agarose gel electrophoresis. Total RNA was used immediately for cDNA synthesis. The Cy dye-labeled cDNA from the amylase-treated aliquot of the culture was mixed with Cy dye-labeled cDNA from the denatured amylase-treated control aliquot, and used to probe the S. gordonii microarray slides. Each amylase-exposure experiment was repeated from four biological replicates. To confirm microarray results the cDNA from each strain was labeled with the opposite Cy dye and hybridized to similar arrays for the flip-dye comparison. Overall design 4 samples were analyzed. The quality controls were 4 biological replicates and dye-swap technical replicates for each biological replicate.

Dataset Information

Secretion stress caused by overexpression of heterologous α-amylase in Bacillus subtilis

Publications

Production and secretion stress caused by overexpression of heterologous alpha-amylase leads to inhibition of sporulation and a prolonged motile phase in Bacillus subtilis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure