Project description:Microarray analysis of Streptococcus pneumoniae TIGR4 transcriptome in response to manganese as the transcriptome changes in response to intracellular manganese accumulation via a mutation in sp1552/mntE a manganese efflux protein. Investigating role of manganese efflux and accumulation in S. pneumoniae: 3 TIGR4 in ThyB vs. TIGR4 in Mn and 3 TIGR4 in Mn vs mntE1 in Mn replicate 3
Project description:Escherichia coli possesses >65 small proteins of <50 amino acids, many of which are uncharacterized. We have identified a new small protein, MntS, involved in manganese homeostasis. Manganese is a critical micronutrient, serving as an enzyme cofactor and protecting against oxidative stress. Yet manganese is toxic in excess and little is known about its function in cells. Bacteria carefully control intracellular manganese levels using the transcription regulator MntR. Before this work, mntH, which encodes a manganese importer, was the only gene known to respond to manganese via MntR repression in E. coli K12. We demonstrated that mntS is another member of the MntR manganese regulon. We also identified yebN, which encodes a putative manganese efflux pump, as the first gene positively regulated by MntR in Enterobacteria. Since MntS is expressed when manganese levels are low, causes manganese sensitivity when overexpressed, and binds manganese, we propose that MntS may be a manganese chaperone. This study reveals new factors involved in manganese regulation and metabolism and expands our knowledge of how small proteins function. Two E. coli strains, MG1655 (wild type) and GSO458 (Delta-mntR) were grown to OD600 ~ 0.5 in M9 glucose media at 37 M-BM-:C and treated with 10 microM MnCl2. In the first experiment, this incubation with 10 microM MnCl2 was for 60 min and in the second experiment, it was for 10 min. RNA was extracted using the hot phenol method and cDNA prepared and hybridized according the manufacturer's instructions (Affymetrix).
Project description:Escherichia coli possesses >65 small proteins of <50 amino acids, many of which are uncharacterized. We have identified a new small protein, MntS, involved in manganese homeostasis. Manganese is a critical micronutrient, serving as an enzyme cofactor and protecting against oxidative stress. Yet manganese is toxic in excess and little is known about its function in cells. Bacteria carefully control intracellular manganese levels using the transcription regulator MntR. Before this work, mntH, which encodes a manganese importer, was the only gene known to respond to manganese via MntR repression in E. coli K12. We demonstrated that mntS is another member of the MntR manganese regulon. We also identified yebN, which encodes a putative manganese efflux pump, as the first gene positively regulated by MntR in Enterobacteria. Since MntS is expressed when manganese levels are low, causes manganese sensitivity when overexpressed, and binds manganese, we propose that MntS may be a manganese chaperone. This study reveals new factors involved in manganese regulation and metabolism and expands our knowledge of how small proteins function.
Project description:The plant pathogen Agrobacterium tumefaciens attaches to and forms biofilms on both biotic and abiotic surfaces. The transition between free-living, planktonic A. tumefaciens and multicellular biofilms is regulated by several well-defined environmental and nutritional inputs, including pH, oxygen tension, and phosphate concentration. In many bacterial species limiting iron levels inhibit attachment and biofilm formation. In several systems intracellular levels of the redox-active manganous (Mn2+) and ferrous (Fe2+) ions are interrelated and have tight corresponding regulation with respect to one another. We show that limiting manganese concentrations elicit similar growth and biofilm phenotypes to those seen under iron-limiting conditions. Microarray analysis comparing gene expression in manganese-replete versus manganese-limiting conditions identified a small number of differentially regulated transcripts. These results indicate that the redox-active manganous and ferrous ions are required for wild-type levels of growth and biofilm formation, and that the manganese-dependent response is primarily post-transcriptional and complementary to, but not redundant with, the iron-dependent response. Four biological replicates, independent RNA preparations, two dye swaps.
Project description:The plant pathogen Agrobacterium tumefaciens attaches to and forms biofilms on both biotic and abiotic surfaces. The transition between free-living, planktonic A. tumefaciens and multicellular biofilms is regulated by several well-defined environmental and nutritional inputs, including pH, oxygen tension, and phosphate concentration. In many bacterial species limiting iron levels inhibit attachment and biofilm formation. In several systems intracellular levels of the redox-active manganous (Mn2+) and ferrous (Fe2+) ions are interrelated and have tight corresponding regulation with respect to one another. We show that limiting manganese concentrations elicit similar growth and biofilm phenotypes to those seen under iron-limiting conditions. Microarray analysis comparing gene expression in manganese-replete versus manganese-limiting conditions identified a small number of differentially regulated transcripts. These results indicate that the redox-active manganous and ferrous ions are required for wild-type levels of growth and biofilm formation, and that the manganese-dependent response is primarily post-transcriptional and complementary to, but not redundant with, the iron-dependent response.
Project description:Transcriptome comparison of Bacillus subtilis 168 grown on solid agar (sample 1-3) or aerated liquid (sample 4-7) 2xSG medium with and without of 0.1 mM manganese.
Project description:Microarray analysis of Streptococcus pneumoniae TIGR4 transcriptome in response to manganese as the transcriptome changes in response to intracellular manganese accumulation via a mutation in sp1552/mntE a manganese efflux protein.