Project description:The physiological and transcriptional response of Nitrosomonas europaea biofilms to phenol and toluene was examined and compared to suspended cells. Biofilms were grown in Drip Flow Biofilm Reactors under continuous flow conditions of growth medium containing ammonia as growth substrate. The responses of N. europaea biofilms to the aromatic hydrocarbons phenol and toluene were determined during short-term (3 h) additions of each compound to the biofilms. Ammonia oxidation in the biofilms was inhibited 50% by 60 uM phenol and 100 uM toluene. These concentrations were chosen for microarray analysis of phenol- and toluene-exposed N. europaea biofilms. Liquid batch cultures of exponentially growing N. europaea cells were harvested alongside the biofilms to determine differential gene expression between attached and suspended growth of N. europaea. Four sample groups of N. europaea cells were used in this study, with biological triplicates of each group. Groups were: Control (untreated) biofilms, phenol-exposed biofilms, toluene-exposed biofilms, and exponentially growing suspended cells. Biofilms were grown in Drip Flow Biofilm Reactors containing 4 independent growth channels and subject to 2 hour inhibition tests. During each experiment, 2 biofilm channels served as control with no inhibitor present and the other 2 biofilm channels were exposed to either 60 uM phenol or 100 uM toluene. Nitrite production was monitored throughout the experiment, and the given concentrations of phenol and toluene resulted in 50% inhibition of ammonia oxidation by the biofilms. Suspended cells were grown in batch reactors. Three 4-plex NimbleGen microarray chips were used, and each chip contained one sample from each experimental group. QC of samples was determined by spectrophotometric methods and using Agilent bioanalyzer traces to determine purity and integrity of RNA and cDNA. A sample tracking report was used to verify the correct hybridization of each sample to the intended array.
Project description:The physiological and transcriptional response of Nitrosomonas europaea biofilms to phenol and toluene was examined and compared to suspended cells. Biofilms were grown in Drip Flow Biofilm Reactors under continuous flow conditions of growth medium containing ammonia as growth substrate. The responses of N. europaea biofilms to the aromatic hydrocarbons phenol and toluene were determined during short-term (3 h) additions of each compound to the biofilms. Ammonia oxidation in the biofilms was inhibited 50% by 60 uM phenol and 100 uM toluene. These concentrations were chosen for microarray analysis of phenol- and toluene-exposed N. europaea biofilms. Liquid batch cultures of exponentially growing N. europaea cells were harvested alongside the biofilms to determine differential gene expression between attached and suspended growth of N. europaea.
Project description:Members of the genus Acinetobacter drag attention due to their importance in microbial pathology and biotechnology. OmpA is a porin with multifaceted functions in different species of Acinetobacter. In this study we identified this protein in Acinetobacter sp. SA01, an efficient phenol degrader strain, in different cellular and sub-cellular compartments (such as OM, OMV, biofilm and extracellular environment). Differential expression of proteins, including OmpA, under two conditions of phenol and ethanol supplementation was assessed using shotgun proteomics.
Project description:We used Affymetrix GeneChips to determine the physiological differences between biofilm and planktonic cells of Bacteroides thetaiotaomicron strain VPI-5482 (ATCC 29148) by comparing gene expression. For this purpose, B. thetaiotaomicron cells were grown in sterile, continuous flow bioreactors fed with tryptone, yeast extract, glucose (TYG) medium. The bioreactors were controlled at a temperature of 37C using a water jacket and a recirculating water heater. After 8 hours post-inoculation, planktonic cells were harvested from the bulk solution in the bioreactor, and after 8 days post-inoculation, the biofilm was scraped from the carbon paper. RNA was harvested from both biofilm and planktonic populations. RNA was extracted by a phenol:chloroform method and purified with a Qiagen RNA Easy mini-kit.
Project description:This SuperSeries is composed of the following subset Series: GSE26421: Expression analysis of benzoate degradation in the hyperthermophilic archaeon Ferroglobus placidus GSE26423: Expression analysis of phenol degradation in the hyperthermophilic archaeon Ferroglobus placidus Refer to individual Series
Project description:We used Affymetrix GeneChips to determine the physiological differences between biofilm and planktonic cells of Bacteroides thetaiotaomicron strain VPI-5482 (ATCC 29148) by comparing gene expression. For this purpose, B. thetaiotaomicron cells were grown in sterile, continuous flow bioreactors fed with tryptone, yeast extract, glucose (TYG) medium. The bioreactors were controlled at a temperature of 37C using a water jacket and a recirculating water heater. After 8 hours post-inoculation, planktonic cells were harvested from the bulk solution in the bioreactor, and after 8 days post-inoculation, the biofilm was scraped from the carbon paper. RNA was harvested from both biofilm and planktonic populations. RNA was extracted by a phenol:chloroform method and purified with a Qiagen RNA Easy mini-kit. Overall growth conditions are summarized above. The experimental conditions were: biofilm (BF), and planktonic (PL).
Project description:Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [14C]-benzene to [14C]-carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism and [14C]-benzoate was produced from [14C]-benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not up-regulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- versus benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms.
Project description:Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [14C]-benzene to [14C]-carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism and [14C]-benzoate was produced from [14C]-benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not up-regulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- versus benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms.