Altered Stationary-Phase Response in a
            <i>Borrelia burgdorferi rpoS</i>
            Mutant

Elias, Abdallah F.; Bono, James L.; Carroll, James A.; Stewart, Philip E.; Tilly, Kit; Rosa, Patricia A.

doi:10.1128/jb.182.10.2909-2918.2000

Cited by 69 publications

(69 citation statements)

References 59 publications

(48 reference statements)

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“…Several studies have implicated the importance of RNA polymerase subunits s S and s N in B. burgdorferi transitional events, including transmission from tick to mammal Elias et al, 2000;Yang et al, 2000). Since the ORF BB0374-pfs-metK-luxS operon is induced during tick-to-mammal transmission (Narasimhan et al, 2002), we examined whether either s S or s N played a role in regulation of operon transcription.…”

Section: Growth Rate Dependent Expression Of the Operonmentioning

confidence: 99%

“…Since the ORF BB0374-pfs-metK-luxS operon is induced during tick-to-mammal transmission (Narasimhan et al, 2002), we examined whether either s S or s N played a role in regulation of operon transcription. The s S subunit is induced as cultures approach stationary phase, and s S levels are dependent on s N Elias et al, 2000;Yang et al, 2000). B. burgdorferi with specific deletions of either rpoS (s S ) or rpoN (s N ) produced luxS transcripts at levels comparable to wild-type bacteria ( Supplementary Fig.…”

Section: Growth Rate Dependent Expression Of the Operonmentioning

confidence: 99%

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Genetic and physiological characterization of the Borrelia burgdorferi ORF BB0374-pfs-metK-luxS operon

et al. 2007

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The Lyme disease spirochaete, Borrelia burgdorferi, produces the LuxS enzyme both in vivo and in vitro; this enzyme catalyses the synthesis of homocysteine and 4,5-dihydroxy-2,3-pentanedione (DPD) from a by-product of methylation reactions. Unlike most bacteria, B. burgdorferi is unable to utilize homocysteine. However, DPD levels alter expression levels of a subset of B. burgdorferi proteins. The present studies demonstrate that a single B. burgdorferi operon encodes both of the enzymes responsible for synthesis of DPD, as well as the enzyme for production of the Lyme spirochaete's only activated-methyl donor and a probable phosphohydrolase. Evidence was found for only a single transcriptional promoter, located 59 of the first gene, which uses the housekeeping s 70 subunit for RNA polymerase holoenzyme function. All four genes are co-expressed, and mRNA levels are growth-rate dependent, being produced during the exponential phase. Thus, high metabolic activity is accompanied by increased cellular levels of the only known borrelial methyl donor, enhanced detoxification of methylation by-products, and increased production of DPD. Therefore, production of DPD is directly correlated with cellular metabolism levels, and may thereby function as an extracellular and/or intracellular signal of bacterial health. INTRODUCTIONLyme disease is an arthropod-borne zoonotic disease affecting humans and many domesticated and wild animals. The causative agent, Borrelia burgdorferi, is readily able to infect both Ixodes spp. ticks and a variety of vertebrate hosts (Steere, 2001). Throughout the processes of infecting these two distinct host types, and transmission between each, B. burgdorferi regulates expression of a large number of both metabolic and host-interface proteins. Deciphering the mechanisms by which B. burgdorferi controls gene and protein expression patterns is providing insights into both the physiology of this bacterium and its pathogenic abilities.Some species of bacteria utilize the metabolic by-product 4,5-dihydroxy-2,3-pentanedione (DPD) in intercellular (and possibly intracellular) signalling. Several different, spontaneously derived forms of DPD have been identified that can function as signals, which are collectively termed 'autoinducer-2' (AI-2) (Chen et al., 2002;Miller et al., 2004). DPD/AI-2 is produced from the toxic end product of transmethylation reactions, S-adenosylhomocysteine (SAH), in a two-step reaction catalysed by the enzymes Pfs and LuxS. Some bacteria, such as the syphilis spirochaete Treponema pallidum, possess Pfs but lack LuxS, and therefore detoxify SAH only to the non-toxic S-ribosylhomocysteine (SRH) (Fraser et al., 1998;von Lackum et al., 2006). Other bacteria, B. burgdorferi included, further degrade SRH to DPD and homocysteine via the LuxS enzyme (Babb et al., 2005;Stevenson & Babb, 2002;Stevenson et al., 2003;Sun et al., 2004;Xavier & Bassler, 2003). The majority of bacteria salvage homocysteine for regeneration of methionine, for use in additional transmethylation reactions or pr...

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Section: Growth Rate Dependent Expression Of the Operonmentioning

confidence: 99%

Section: Growth Rate Dependent Expression Of the Operonmentioning

confidence: 99%

Genetic and physiological characterization of the Borrelia burgdorferi ORF BB0374-pfs-metK-luxS operon

et al. 2007

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“…Initial studies have demonstrated that cN40 and infectious clones derived from cN40 can be transformed by electroporation, although the frequency of transformation was approximately 100-fold lower than what was observed with a noninfectious clone of B. burgdorferi B31 (P. Rosa, unpublished results). Transformation of B. burgdorferi has previously only been demonstrated in noninfectious B. burgdorferi B31 (4,9,23,29). Recently, Stewart and his colleagues succeeded in transforming infectious spirochetes with a shuttle vector capable of autonomous replication in B. burgdorferi (30).…”

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confidence: 99%

Dissociation of Infectivity and Pathogenicity in Borrelia burgdorferi

et al. 2001

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Clonal Borrelia burgdorferi N40 (cN40) passaged 75 times in vitro (N40-75) infects mice but does not cause disease. N40-75 passaged 45 times further in vitro (N40-120) was no longer infectious and lacked genes encoded on linear plasmids 38 and 28-1, among other differences. These data suggest that B. burgdorferi cN40, N40-75, and N40-120 have distinct phenotypes that can be used to dissect the genetic elements responsible for pathogenicity and infectivity.

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“…The mutant was constructed by inactivating the rpoS locus in the chromosome by allelic exchange with gyrB r , a mutated form of the B subunit of DNA gyrase, as a selectable marker. Elias et al (2000) demonstrated that RpoS facilitates the upregulation of genes involved in entry into stationary phase. The mutant exhibited increased sensitivity to osmotic stress, which is consistent with the finding that wild-type B. burgdorferi had a growth phase-dependent resistance to 1N…”

Section: A Stationary Phasementioning

confidence: 99%

“…The GyrA protein has been demonstrated to be essential in B. burgdorferi ; however, mutations have been introduced successfully into the gyrB allele (gyrB r ) along with a coumermycin A1 resistance (Cou r ) marker. Applying this genetic method, Elias et al (2000) inactivated the rpoS locus by allelic exchange with gyrB r as a selectable marker. To date, coumermycin resistance is the selectable marker of choice for genetic studies in B.…”

Section: B Organization Of Borrelial Promotersmentioning

confidence: 99%

Characterization of secA-sod operon in Borrellia burgdorferi.

Nichols¹

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Borrelia burgdorferi, the causative agent of Lyme disease, has been characterized as a microaerophilic spirochete. O2 consumption and utilization potentially yield reactive oxygen intermediates, such as superoxide, hydroxyl radicals, and hydrogen peroxide. This study investigated the expression of the sod gene, which encodes the only, identified oxidative defense mechanism in B. burgdorferi. Using primer extension analysis and RT-PCR, it was found that sod and secA are organized as a single transcriptional unit under the control of σ 70 -like promoter upstream of the secA open reading frame. Generally, gene expression decreases with increased distance from the promoter; however, secA expression was observed to be relatively lower amounts than sod. Both genes were expressed in all phases of growth, with greatest expression observed in stationary phase. Because transcription of most sod genes is tightly regulated by iron concentration, the secA-sod gene expression was analyzed in borrelial cells grown in varying amounts of metal. Ironrestriction did not significantly affect growth nor did it affect transcription of secA or sod.Likewise, no major differences in transcription were observed with restricting or supplementing media with manganese. To test the possibility that the borrelial SOD may function with either iron or manganese as a cofactor as in cambialistic SODs, SOD activity was assayed and the highest activity was observed in increased manganese concentrations.Protein expression profiles of Sh-2-82 cultured in metal-defined media were investigated by one-and two-dimensional gel electrophoresis. Approximately 15 proteins were differentially expressed in response to metal concentration. iv ACKNOWLEDGMENTS

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Altered Stationary-Phase Response in a Borrelia burgdorferi rpoS Mutant

Cited by 69 publications

References 59 publications

Genetic and physiological characterization of the Borrelia burgdorferi ORF BB0374-pfs-metK-luxS operon

Genetic and physiological characterization of the Borrelia burgdorferi ORF BB0374-pfs-metK-luxS operon

Dissociation of Infectivity and Pathogenicity in Borrelia burgdorferi

Characterization of secA-sod operon in Borrellia burgdorferi.

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