@article {701, title = {Benefits of in-situ synthesized microarrays for analysis of gene expression in understudied microorganisms.}, journal = {J Microbiol Methods}, volume = {74}, year = {2008}, month = {2008 Jul}, pages = {26-32}, abstract = {Although the genome sequences of many microorganisms are now known, whole-genome DNA microarray platforms consisting of PCR amplicon, or oligonucleotide elements printed onto glass slides have been readily available for only a relatively few, highly studied microorganisms. For those microorganisms more recently cultured or studied by fewer investigators it has been difficult to justify the initial time and expense of developing such array platforms especially if only a limited number of gene expression studies are envisioned. However, in-situ synthesized oligonucleotide (ISO) arrays can be inexpensively fabricated on an {\textquoteright}as needed{\textquoteright} basis with a reduced initial investment in time, personnel, resources, and costs. To evaluate the performance of one ISO array platform, gene expression patterns in Geobacter sulfurreducens under nitrogen-fixing conditions were compared with results from quantitative reverse transcriptase PCR (qRT-PCR) and previously published data from a similar experiment using spotted PCR amplicon arrays. There were strong correlations between the results of the ISO arrays and the results from qRT-PCR (r(2)=0.762) and spotted array (r(2)=0.744) analyses. After initial use the ISO arrays could be successfully stripped and reused. The increased flexibility in array design and reusability coupled with a lower initial investment in terms of fabrication time and cost for the ISO arrays suggest that they may be the preferred approach when investigating gene expression in microorganisms, especially when only a few expression studies are required.}, keywords = {Bacterial Proteins, Computational Biology, Gene Expression, Geobacter, Nitrogen Fixation, Oligonucleotide Array Sequence Analysis, Oligonucleotides, Polymerase Chain Reaction}, issn = {0167-7012}, doi = {10.1016/j.mimet.2007.07.004}, author = {Postier, Bradley and DiDonato, Raymond and Nevin, Kelly P and Liu, Anna and Frank, Bryan and Lovley, Derek and Methe, Barbara A} } @article {702, title = {Differential protein expression in the metal-reducing bacterium Geobacter sulfurreducens strain PCA grown with fumarate or ferric citrate.}, journal = {Proteomics}, volume = {6}, year = {2006}, month = {2006 Jan}, pages = {632-40}, abstract = {Geobacter sulfurreducens, generally considered to be a strict anaerobe, is a predominant microbe in subsurface environments, where it utilizes available metals as electron acceptors. To better understand the metabolic processes involved in the metal-reduction capability of this microbe, the proteins expressed by cells grown anaerobically with either fumarate or ferric citrate as electron acceptor were compared. Proteins were separated by 2-DE under denaturing or nondenaturing conditions, and proteins varying in abundance with a high level of statistical significance (p<0.0001) were identified by peptide mass analysis. Denaturing 2-DE revealed significant differences in the relative abundance of the membrane proteins OmpA and peptidoglycan-associated lipoprotein, several metabolic enzymes, and, in addition, superoxide dismutase and rubredoxin oxidoreductase. Nondenaturing 2-DE revealed elevated catalase in cells grown with ferric citrate. These results suggest that, in addition to adjustments in membrane transport and specific metabolic pathways in response to these two different electron acceptors, distinct differences exist in the oxidative environment within the cell when fumarate or soluble ferric citrate is provided as electron acceptor. Although an anaerobe, G. sulfurreducens appears to have alternate mechanisms for dealing with reactive oxygen species in response to increased intracellular soluble iron.}, keywords = {Anaerobiosis, Bacterial Proteins, Electrophoresis, Gel, Two-Dimensional, Ferric Compounds, Fumarates, Geobacter, Oxidation-Reduction, Proteomics, Reactive Oxygen Species, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization}, issn = {1615-9853}, doi = {10.1002/pmic.200500137}, author = {Khare, Tripti and Esteve-N{\'u}{\~n}ez, Abraham and Nevin, Kelly P and Zhu, Wenhong and Yates, John R and Lovley, Derek and Giometti, Carol S} }