Swarm-cell differentiation in Salmonella enterica serovar Typhimurium (S. typhimurium) results in a biosynthetic mode of growth, despite growing on a rich medium, and cells that have elevated antibiotic resistance. These phenotypes are not a prerequisite for swarm motility. By blocking the switch to anabolic growth using amino acid auxotrophs and screening for the presence of elevated antibiotic resistance in the swarm state, we found that cysteine biosynthesis is crucial for complete swarm-cell differentiation. Mutants were made in each cys biosynthetic operon and all had decreased antibiotic resistance in the swarm state, while swim-cell resistance remained the same as that of wild-type cells. This swarm-state-specific decreased resistance in Δcys strains could be restored to wild-type levels by the addition of cysteine to swarm medium. Two regulatory mutants, ΔcysB and ΔcysE, failed to swarm unless cysteine was supplemented to the medium. We show that all CysB-responsive operons involved in cysteine biosynthesis are upregulated in the swarm state, even though swarm cells are cultivated on a medium that represses cysteine biosynthesis in the swim state. While swarm medium has sufficient cysteine for growth of S. typhimurium, it does not contain enough for swarm-cell differentiation. We hypothesize that in these cells, the additional cysteine requirement is for use in pathways not directly related to cell growth.
AllisonC.,
LaiH. C.,
HughesC.1992a; Co-ordinate expression of virulence genes during swarm-cell differentiation and population migration of Proteus mirabilis
. Mol Microbiol 6:1583–1591
AllisonC.,
ColemanN.,
JonesP. L.,
HughesC.1992b; Ability of Proteus mirabilis to invade human urothelial cells is coupled to motility and swarming differentiation. Infect Immun 60:4740–4746
AntonD. N.2000; Induction of the cysteine regulon of Salmonella typhimurium in LB medium affects the response of cysB mutants to mecillinam. Curr Microbiol 40:72–77
BjarnasonJ.,
SouthwardC. M.,
SuretteM. G.2003; Genomic profiling of iron-responsive genes in Salmonella enterica serovar Typhimurium by high-throughput screening of a random promoter library. J Bacteriol 185:4973–4982
BurkartM.,
ToguchiA.,
HarsheyR. M.1998; The chemotaxis system, but not chemotaxis, is essential for swarming motility in Escherichia coli
. Proc Natl Acad Sci U S A 95:2568–2573
Carmel-HarelO.,
StorzG.2000; Roles of the glutathione- and thioredoxin-dependent reduction systems in the Escherichia coli and Saccharomyces cerevisiae responses to oxidative stress. Annu Rev Microbiol 54:439–461
CostaC. S.,
AntonD. N.2006; High-level resistance to mecillinam produced by inactivation of soluble lytic transglycosylase in Salmonella enterica serovar Typhimurium. FEMS Microbiol Lett 256:311–317
DatsenkoK. A.,
WannerB. L.2000; One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc Natl Acad Sci U S A 97:6640–6645
EavesD. J.,
RicciV.,
PiddockL. J. V.2004; Expression of acrB, acrF, acrD, marA, and soxS in Salmonella enterica serovar Typhimurium: role in multiple antibiotic resistance. Antimicrob Agents Chemother 48:1145–1150
HarsheyR. M.,
MatsuyamaT.1994; Dimorphic transition in Escherichia coli and Salmonella typhimurium: surface-induced differentiation into hyperflagellate swarmer cells. Proc Natl Acad Sci U S A 91:8631–8635
HryniewiczM. M.,
KredichN. M.1991; The cysP promoter of Salmonella typhimurium: characterization of two binding sites for CysB protein, studies of in vivo transcription initiation, and demonstration of the anti-inducer effects of thiosulfate. J Bacteriol 173:5876–5886
KimW.,
SuretteM. G.2003; Swarming populations of Salmonella represent a unique physiological state coupled to multiple mechanisms of antibiotic resistance. Biol Proced Online 5:189–196
KimW.,
SuretteM. G.2006; Coordinated regulation of two independent cell-cell signalling systems and swarmer differentiation in Salmonella enterica serovar Typhimurium. J Bacteriol 188:431–440
KredichN. M.1971; Regulation of l-cysteine biosynthesis in Salmonella typhimurium. I. Effects of growth on varying sulfur sources and O-acetyl-l-serine on gene expression. J Biol Chem 246:3474–3484
LiawS.-J.,
LaiH.-C.,
HoS.-W.,
LuhK.-T.,
WangW.-B.2003; Role of RsmA in the regulation of swarming motility and virulence factor expression in Proteus mirabilis
. J Med Microbiol 52:19–28
LilicM.,
JovanovicM.,
JovanovicG.,
SavicD. J.2003; Identification of the CysB-regulated gene, hslJ, related to the Escherichia coli novobiocin resistance phenotype. FEMS Microbiol Lett 224:239–246
NeuwaldA. F.,
KrishnanB. R.,
BrikunI.,
KulakauskasS.,
SuziedelisK.,
TomcsanyiT.,
LeyhT. S.,
BergD. E.1992; cysQ, a gene needed for cysteine synthesis in Escherichia coli K-12 only during aerobic growth. J Bacteriol 174:415–425
OstrowskiJ.,
KredichN. M.1990; In vitro interactions of CysB protein with the cysJIH promoter of Salmonella typhimurium: inhibitory effects of sulfide. J Bacteriol 172:779–785
QuanJ. A.,
SchneiderB. L.,
PaulsenI. T.,
YamadaM.,
KredichN. M.,
SaierM. H.Jr2002; Regulation of carbon utilization by sulfur availability in Escherichia coli and Salmonella typhimurium
. Microbiology 148:123–131
ShiX.,
BennettG. N.1994; Effects of rpoA and cysB mutations on acid induction of biodegradative arginine decarboxylase in Escherichia coli
. J Bacteriol 176:7017–7023
SirkoA.,
ZatykaM.,
SadowyE.,
HulanickaD.1995; Sulfate and thiosulfate transport in Escherichia coli K-12: evidence for a functional overlapping of sulfate- and thiosulfate-binding proteins. J Bacteriol 177:4134–4136
StecE.,
Witkowska-ZimnyM.,
HryniewiczM. M.,
NeumannP.,
WilkinsonA. J.,
BrzozowskiA. M.,
VermaC. S.,
ZaimJ.,
WysockiS.,
BujaczG. D.2006; Structural basis of the sulphate starvation response in Escherichia coli: crystal structure and mutational analysis of the cofactor-binding domain of the Cbl transcriptional regulator. J Mol Biol 364:309–322
SturgillG.,
ToutainC. M.,
KomperdaJ.,
O'TooleG. A.,
RatherP. N.2004; Role of CysE in production of an extracellular signaling molecule in Providencia stuartii and Escherichia coli: loss of cysE enhances biofilm formation in Escherichia coli
. J Bacteriol 186:7610–7617
Van Der PloegJ. R.,
Iwanicka-NowickaR.,
KerteszM. A.,
LeisingerT.,
HryniewiczM. M.1997; Involvement of CysB and Cbl regulatory proteins in expression of the tauABCD operon and other sulfate starvation-inducible genes in Escherichia coli
. J Bacteriol 179:7671–7678