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Transcriptional Profiling Of Caulobacter Crescentus During Growth On Complex And Minimal Media, Craig Stephens, Alison K. Hottes, Maliwan Meewan, Desiree Yang, Naomi Arana, Pedro Romero, Harley H. Mcadams.
Transcriptional Profiling Of Caulobacter Crescentus During Growth On Complex And Minimal Media, Craig Stephens, Alison K. Hottes, Maliwan Meewan, Desiree Yang, Naomi Arana, Pedro Romero, Harley H. Mcadams.
Biology
Microarray analysis was used to examine gene expression in the freshwater oligotrophic bacterium Caulobacter crescentus during growth on three standard laboratory media, including peptone-yeast extract medium (PYE) and minimal salts medium with glucose or xylose as the carbon source. Nearly 400 genes (approximately 10% of the genome) varied significantly in expression between at least two of these media. The differentially expressed genes included many encoding transport systems, most notably diverse TonB-dependent outer membrane channels of unknown substrate specificity. Amino acid degradation pathways constituted the largest class of genes induced in PYE. In contrast, many of the genes upregulated in minimal …
Use Of The Caulobacter Crescentus Genome Sequence To Develop A Method For Systematic Genetic Mapping, Craig Stephens, Lisandra West, Desiree Yang
Use Of The Caulobacter Crescentus Genome Sequence To Develop A Method For Systematic Genetic Mapping, Craig Stephens, Lisandra West, Desiree Yang
Biology
The functional analysis of sequenced genomes will be facilitated by the development of tools for the rapid mapping of mutations. We have developed a systematic approach to genetic mapping in Caulobacter crescentus that is based on bacteriophage-mediated transduction of strategically placed antibiotic resistance markers. The genomic DNA sequence was used to identify sites distributed evenly around the chromosome at which plasmids could be nondisruptively integrated. DNA fragments from these sites were amplified by PCR and cloned into a kanamycin-resistant (Kanr) suicide vector. Delivery of these plasmids into C. crescentus resulted in integration via homologous recombination. A set of 41 strains …
A Cell Cycle-Regulated Adenine Dna Methyltransferase From Caulobacter Crescentus Processively Methylates Gantc Sites On Hemimethylated Dna, Craig Stephens, Anthony J. Berdis, Irene Lee, James K. Coward, Rachel Wright, Lucy Shapiro, Stephen J. Benkovic
A Cell Cycle-Regulated Adenine Dna Methyltransferase From Caulobacter Crescentus Processively Methylates Gantc Sites On Hemimethylated Dna, Craig Stephens, Anthony J. Berdis, Irene Lee, James K. Coward, Rachel Wright, Lucy Shapiro, Stephen J. Benkovic
Biology
The kinetic properties of an adenine DNA methyltransferase involved in cell cycle regulation of Caulobacter crescentus have been elucidated by using defined unmethylated or hemimethylated DNA (DNAHM) substrates. Catalytic efficiency is significantly enhanced with a DNAHM substrate. Biphasic kinetic behavior during methyl incorporation is observed when unmethylated or DNAHM substrates are used, indicating that a step after chemistry limits enzyme turnover and is most likely the release of enzyme from methylated DNA product. The enzyme is thermally inactivated at 30 degrees C within 20 min; this process is substantially decreased in the presence of saturating concentrations of DNAHM, suggesting that …
The Ccrm Dna Methyltransferase Is Widespread In The Alpha Subdivision Of Proteobacteria, And Its Essential Functions Are Conserved In Rhizobium Meliloti And Caulobacter Crescentus, Craig Stephens, Rachel Wright, Lucy Shapiro
The Ccrm Dna Methyltransferase Is Widespread In The Alpha Subdivision Of Proteobacteria, And Its Essential Functions Are Conserved In Rhizobium Meliloti And Caulobacter Crescentus, Craig Stephens, Rachel Wright, Lucy Shapiro
Biology
The Caulobacter crescentus DNA methyltransferase CcrM (M.CcrMI) methylates the adenine residue in the sequence GANTC. The CcrM DNA methyltransferase is essential for viability, but it does not appear to be part of a DNA restriction-modification system. CcrM homologs are widespread in the alpha subdivision of gram-negative bacteria. We have amplified and sequenced a 258-bp region of the cerM gene from several of these bacteria, including Rhizobium meliloti, Brucella abortus, Agrobacterium tumefaciens, and Rhodobacter capsulatus. Alignment of the deduced amino acid sequences revealed that these proteins constitute a highly conserved DNA methyltransferase family. Isolation of the full-length ccrM genes from the …
Identification Of The Flii And Flij Components Of The Caulobacter Flagellar Type Iii Protein Secretion System, Craig Stephens, Chris Mohr, Charles Boyd, Janine Maddock, James Gober, Lucy Shapiro
Identification Of The Flii And Flij Components Of The Caulobacter Flagellar Type Iii Protein Secretion System, Craig Stephens, Chris Mohr, Charles Boyd, Janine Maddock, James Gober, Lucy Shapiro
Biology
Caulobacter crescentus is motile by virtue of a polar flagellum assembled during the predivisional stage of the cell cycle. Three mutant strains in which flagellar assembly was blocked at an early stage were isolated. The mutations in these strains mapped to an operon of two genes, fliI and fliJ, both of which are necessary for motility. fliI encodes a 50-kDa polypeptide whose sequence is closely related to that of the Salmonella typhimurium FliI protein, an ATPase thought to energize the export of flagellar subunits across the cytoplasmic membrane through a type III protein secretion system. fliJ encodes a 16-kDa hydrophilic …