Transcription profiling of G sulfurreducens GGS18 electrodes
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ABSTRACT: G. sulfurreducens (ATCC #51573) was obtained from the laboratory culture collection of Dr. Derek Lovley. Cells were grown under strict anaerobic conditions at 23 �Â�°C in batch culture. Both control and experimental populations were grown with 10mM acetate as the electron donor while Fe(III) as 55 mM ferric citrate served as the electron acceptor for the control populations and graphite anodes as the electron acceptor for the experimental populations. Controls populations were harvested at a concentration of 30 mM Fe(II). Fuel cell power output was monitored by measuring the voltage across a known resistance in the fuel cell and experimental populations were harvested when current production reached a steady state of 0.6 milliamperes. Cells were harvested at log phase by centrifugation at 4 �Â�°C and the cell pellet was flash-frozen in liquid nitrogen and then stored at -80 �Â�°C prior to RNA extraction. Three cultures of control and experimental populations were collected. Each culture vessel was harvested and extracted for total RNA separately to produce three biological replicates for this experiment. Additional information regarding the fuel cell experimental set up and culture conditions for this experiment can be found in both the current reference and the following reference: Bond DR and Lovley DR. Electricity production by Geobacter sulfurreducens attached to electrodes. 2003. Applied and Environmental Microbiology 69: 1548-1555.
Project description:G. sulfurreducens (ATCC #51573) was obtained from the laboratory culture collection of Dr. Derek Lovley. Cells were grown under strict anaerobic conditions at 23 °C in batch culture. Both control and experimental populations were grown with 10mM acetate as the electron donor while Fe(III) as 55 mM ferric citrate served as the electron acceptor for the control populations and graphite anodes as the electron acceptor for the experimental populations. Controls populations were harvested at a concentration of 30 mM Fe(II). Fuel cell power output was monitored by measuring the voltage across a known resistance in the fuel cell and experimental populations were harvested when current production reached a steady state of 0.6 milliamperes. Cells were harvested at log phase by centrifugation at 4 °C and the cell pellet was flash-frozen in liquid nitrogen and then stored at -80 °C prior to RNA extraction. Three cultures of control and experimental populations were collected. Each culture vessel was harvested and extracted for total RNA separately to produce three biological replicates for this experiment. Additional information regarding the fuel cell experimental set up and culture conditions for this experiment can be found in both the current reference and the following reference: Bond DR and Lovley DR. Electricity production by Geobacter sulfurreducens attached to electrodes. 2003. Applied and Environmental Microbiology 69: 1548-1555.
Project description:pBL1 is a Lactococcus lactis theta-replicating 10.9-kbp plasmid that encodes the synthetic machinery of the bacteriocin Lcn972. In this work, the transcriptomes of exponentially growing L. lactis with and without pBL1 were compared. A discrete response was observed with a total of ten genes showing significantly changed expression. Up-regulation of the lactococcal oligopeptide uptake system (opp) was observed, likely linked to a higher nitrogen demand required for Lcn972 biosynthesis. Striking, celB coding for the membrane porter IIC of the cellobiose-PTS and the upstream gene llmg0186 were down-regulated. Growth profiles for L. lactis strains MG1363, MG1363/pBL1 and MG1363ΔcelB grown in CDM-cellobiose confirmed slower growth of pBL1 and ΔcelB while no differences were scored on glucose. The presence of pBL1 shifted the fermentation products towards a mixed acid profile and promoted substantial changes in intracellular pool sizes for glycolytic intermediates in cellobiose-growing cells as determined by HPLC and NMR. Overall, these data support the genetic evidence of a constriction in cellobiose uptake. Notably, several cell wall precursors accumulated, while other UDP-activated sugars pools were lower, which could reflect rerouting of precursors towards the production of structural or storage polysaccharides. Moreover, slow cellobiose-growing cells and those lacking celB were more tolerant to Lcn972 than cellobiose adapted cells. Thus, down-regulation of celB could help to build-up a response against the antimicrobial activity of Lcn972 enhancing self-immunity of the producer cells. The transcriptomes of Lactococcus lactis MG1614 with and without the bacteriocinogenic plasmid pBL1, grown under laboratory conditions, were compared using three biological replicates.
Project description:It has been performed a genome-wide analysis of gene expression of the root-colonizing bacterium Pseudomonas putida KT2440 in the rhizosphere of corn (Zea mays var. Girona. To identify reliable rhizosphere differentially expressed genes, rhizosphere populations of P. putida bacteria cells were compared with three alternative controls: i) planktonic cells growing exponentially in rich medium (LB), ii) planktonic cells in stationary phase in LB, and iii) sessile populations established in sand microcosms, under the same conditions used to grow inoculated corn plants.
Project description:Background: Niemann Pick type C disease (NPC) is a neurovisceral lipid storage disorder, characterized by unesterified cholesterol accumulation in lysosomal/late endosome compartments. The main tissues affected in the disease are the liver and the cerebellum. Although the primary defect in this disease occurs in the liver, the pathological mechanisms involved in hepatocyte damage and death have been poorly explored. Here, we assessed biochemical parameters, liver histology and the mRNA abundance of genes encoding proteins associated to oxidative stress, copper metabolism, fibrosis and inflammation and cholesterol metabolism in livers of WT and NPC mice. Methodology/Principal Findings: We found that the histology of NPC mice livers show signals of inflammation and fibrosis. This was correlated with an increase of carbonylated proteins and reduced glutathione content in the liver, as well as a significantly increment of total content of copper in liver tissue. Finally, we analyzed the liver gene expression pattern by qPCR and microarray assays. We found a correlation between the tissue fibrotic status and a differential hepatic expression of genes related to oxidative stress, fibrosis and inflammation processes in NPC mice. Conclusions/Significance: Our data show that NPC liver disease is evidenced by an increase in fibrosis as well as in oxidative stress status. Concomitantly, there is a correlation with an altered gene expression pattern, mainly of oxidative stress and fibrosis related genes, which could be useful as a potential disease progression biomarkers. We compared three liver samples from NPC mice to a common reference sample made from pooled mRNA of three wild type mice
Project description:G. sulfurreducens (ATCC #51573) was obtained from the laboratory culture collection of Dr. Derek Lovley. Cells were grown under strict anaerobic conditions at 30 °C in chemostats, as previously described (for more information see Esteve-Núñez, A., M. M. Rothermich, M. Sharma, and D. R. Lovley. 2004. Growth of Geobacter sulfurreducens under nutrient-limiting conditions in continuous culture. Environ. Microbiol.:in press.), with acetate (5 mM) as the electron donor and fumarate (27.5 mM) as the electron acceptor. For growth in the absence of fixed nitrogen, the ammonium chloride (4.7 mM) was omitted from the medium and fumarate served as the electron acceptor. Therefore, cultures with ammonium chloride were limited by acetate while cultures without ammonium chloride were limited by nitrogen. Cultures were maintained at a dilution rate of 0.05 h-1 for 5 culture vessel volumes to ensure that cells were at steady-state prior to harvesting. Cells were harvested by centrifugation at 4 °C and the cell pellet was flash-frozen in liquid nitrogen and then stored at -80 °C prior to RNA extraction. Cells grown in the absence of ammonium had acetylene reduction rates of 0.012 nmol/hr compared to 0.003 nmol/hr in ammonium-grown cells, providing evidence that these cells were fixing nitrogen.. The steady-state concentration of cells in the nitrogen-fixing chemostats (0.178 mg/mL + 0.011; mean + standard deviation, n=3) was significantly lower than chemostats provided with ammonium (0.45 mg/mL + 0.007). Three cultures of acetate limited growth with fumarate as the electron acceptor and three cultures of nitrogen limited growth with fumarate as the electron acceptor were grown. Each culture vessel was harvested and extracted for total RNA separately to produce three biological replicates for this experiment.
Project description:Investigation of whole genome gene expression level changes in GFP+ and GFP- populations of B.subtilis strain DS901 An 8 chip study using total RNA recovered from B.subtilis strain DS901 (Phag-gfp). With a Cytopeia Influx cell sorter, cells were sorted in GFP+ and GFP- populations. Each B. subtilis subsp. subtilis strain 168 NC_000964 chip measures the expression level of 4,104 genes in two-fold from with eight 60-mer probe pairs (PM/MM) per gene.