2000), and top vertebrate predators typically disappear from all but the largest habitat fragments (Terborgh et al. 2001). Similarly, Zabel and Tscharnke (1998) found CH5424802 research buy insect predators to be more sensitive to habitat patch isolation than insect herbivores. Among non-rare arthropod species in the present study, there was no evidence that carnivores were more vulnerable to invasive ants than were herbivores or detritivores. Among rare species, however, trophic role was significantly related to vulnerability,

but only for endemic species. Rare endemic carnivores were by far the most likely group to be absent in ant-invaded plots (Table 2), with vulnerable species belonging to six different taxonomic orders. Rare endemic detritivores were the next most vulnerable group. One reason that carnivore species are often at risk is that they tend to exist at lower densities than herbivores and detritivores. But in these

communities, trophic role was most clearly important for rare species, among which population density varied little. Instead, endemic carnivores at our study sites may be especially vulnerable to invasive ants because, in addition to experiencing direct predation and interference competition for feeding or refuge sites, they may also experience exploitation competition for prey resources. Invasive ants are also efficient scavengers, so they may similarly compete with some detritivores or omnivores for food resources (McNatty et al. 2009), although it has also been hypothesized that some detritivores may enjoy an increased resource base consisting of abundant ant carcasses Ispinesib research buy in invaded areas (Porter and Savignano 1990; Cole et al. 1992). Herbivores, as a group, may be least vulnerable SGC-CBP30 mouse because most of them will not be competing with ants for food resources

to any great extent. In addition, some endemic herbivores, such as delphacid planthoppers, are tolerated by ants, perhaps because they produce honeydew (Krushelnycky 2007, Supplementary Tables 2 and 3). Finally, we found no association between body size and the likelihood or magnitude of population reduction as a result of ant invasion, regardless of whether a species was rare or not, or whether we ADAMTS5 controlled for other explanatory factors, including phylogenetic trends. Large body size is often correlated with other factors thought to increase vulnerability in animals, such as lower fecundity, slower development, lower abundance or density and larger range requirements (Reynolds 2003). These associations, however, do not always hold, leading to much variation among taxa in the relationship between size and vulnerability (McKinney 1997; Fisher and Owens 2004). In the present study, larger species had slightly lower densities and tended to occupy higher trophic positions than smaller species, which should make larger species less resilient to losses from ant predation.

The fliC gene appears however not to be useful for distinguishing between R. pickettii and R. insidiosa based on our findings. The division of the groups did not correlate to clinical or environmental association or to their location of isolation. The reasons for the variation learn more between the 16S-23S spacer region and the fliC gene could be potentially due to the structure of the fliC gene. This is demonstrated by Burkholderia flagellin sequences, which exhibit high levels of homology in the conserved terminal regions but differ considerably in the central region [57]. Variation

is a common feature of flagellin proteins, which are believed to fold into a hairpin-like conformation, with the terminal domains being responsible for defining the basic filament structure lying on the inner surface and the central, variable region being surface exposed [58]. In a previous epidemiological study involving sixteen isolates of R. pickettii, eight PS-341 cell line different RAPD profiles were observed for isolates coming from blood culture, distilled water and an aqueous chlorhexidine solution [16]. In another study, involving fourteen isolates of R. pickettii from various biological samples the same RAPD pattern was found in all instances [59], while Pasticci et al., carried out a study involving fifteen isolates of

R. pickettii KU-60019 molecular weight that gave three patterns [27]. The results of our study with a larger number of isolates indicated that there is some diversity in the studied populations but that this is limited and isolates from different environments grouped together. The results obtained with BOX-PCR showed nineteen different profiles among the fifty-nine isolates examined again demonstrating limited diversity (Figure 3b). To the best of our knowledge this is the first reported study of the diversity of R. pickettii and R. insidiosa carried out with BOX-PCR. A similar study carried by Coenye et al., on ninety-seven B. cepacia

Genomovar III isolates Aldol condensation found 20 different patterns with a DI value of 0.821 [60]. The molecular fingerprinting methods used here yielded rapid and reproducible fingerprints for clinical and environmental isolates of R. pickettii and R. insidiosa. Presently, little is known regarding the source of R. pickettii isolates occurring in hospital environments. Investigations by other authors have reported no evidence of patient-to-patient transmission, and they suggest that multiple independent acquisitions from environmental sources could be an important mode of transmission of R. pickettii [5]. The most common sites of contamination were blood-sampling tubes, dialysis machines, nebulizers and other items frequently in contact with water [5]. Conclusions BOX-PCR and RAPD typing was found to be more discriminatory than the typing of genes in R. pickettii such as the fliC gene or the ISR. The majority of isolates were shown to possess similar genotypes by both BOX and RAPD-PCR (Figure 3a, b).

The EPZ5676 supplier achromobactin biosynthetic pathway is a particularly valuable resource for the study of these enzymes as it relies on the action of all three types of synthetase click here [22, 24]. Achromobactin has been shown to be important for virulence in Dickeya dadantii (formerly Erwinia chrysanthemi) [25], and both pyoverdine and achromobactin contribute to epiphytic fitness of P. syringae pv. syringae 22d/93 [21], but the contribution of siderophores

to virulence of P. syringae 1448a has not previously been characterized. We therefore examined the roles of both achromobactin and pyoverdine in virulence of P. syringae 1448a, as well as their relative contribution to iron uptake and growth under more precisely defined conditions. Results Identification Everolimus price and in silico characterization of the P. syringae 1448a pyoverdine locus The biosynthesis of pyoverdine has been most extensively studied in P. aeruginosa PAO1 and most, if not all, of the genes required for pyoverdine synthesis in this strain have now been identified [[6, 10, 26]]. Ravel and Cornelis [8] used the PAO1 pyoverdine genetic locus as a blueprint for annotation of the pyoverdine loci from three other fluorescent pseudomonads, including P. syringae pv. tomato DC3000. We adopted a similar strategy to interrogate

the P. syringae 1448a genome, individually BLASTP searching all of the known PAO1 pyoverdine proteins against the P. syringae 1448a sequence database [27]. The genomic organization of pyoverdine genes in P. syringae 1448a is highly similar to the C1GALT1 P. syringae DC3000 genetic locus presented by Ravel and Cornelis [8], but less similar to that of PAO1 (Figure 1A, Table 1). Given the similarity with the P. syringae DC3000 genetic locus and the excellent earlier analysis of Ravel and Cornelis, we confine our analysis of the non-NRPS genes of P. syringae 1448a to two aspects not previously noted by them. The first concerns the only PAO1 gene that clearly lacks an ortholog in P. syringae, pvdF, which encodes an enzyme required for generating the N5-formyl-N5-hydroxyornithine residues that are present in the PAO1 (but not P. syringae) pyoverdine side chain. Instead,

P. syringae 1448a contains a gene (Pspph1922; marked * in Figure 1A) that is 37% identical at a predicted protein level to the syrP gene of Pseudomonas syringae pv. syringae. Originally mis-annotated as a putative regulatory gene, SyrP has subsequently been shown to be an aspartate hydroxylase that is required for synthesis of the NRPS-derived phytotoxin syringomycin [28]. On this basis we propose that Pspph1922 very likely catalyzes β-hydroxylation of two hydroxyaspartate residues expected to be present in the P. syringae 1448a pyoverdine side chain (Figure 1B), with equivalent iron-chelating roles to the N5-formyl-N5-hydroxyornithine residues of PAO1 pyoverdine. We also note that P. syringae 1448a contains two orthologs of the PAO1 ferripyoverdine receptor gene fpvA.

The distinct genetic divergence and gene organisation patterns of these learn more catabolons suggest disparate evolutionary origins, [12]. In relation to the identification and characterisation of styrene linked

PACoA catabolons, several strain specific traits have been reported in Pseudomonas species studied to date. Comparative analyses of sty gene sequences from Pseudomonas putida CA-3, Pseudomonas fluorescens ST, Pseudomonas species Y2 and Pseudomonas sp VLB120 reveal a high degree of similarity in terms of percentage identity and structural organisation, [1]. However, functional characterisations in P. putida CA-3 and P. fluorescens ST have identified different regulatory profiles in relation to catabolite repression inducing carbon sources and nutrient limitation exposure [6, 7, 13, 14]. With respect to the PACoA catabolon, an essential phenylacetic acid uptake mechanism has previously been characterised in Pseudomonas

putida U, co-ordinately expressed with the catabolic genes [10]. In contrast, a recent proteomic analysis of styrene grown P. putida CA-3 cells indicated that phenylacetic acid transport gene products were not detected in styrene grown CA-3, despite the expression of all other PACoA catabolon proteins [15]. Bioinformatic analysis of PACoA catabolon gene organisation in 102 microbial genomes revealed repeated de novo clustering of the catabolic genes [3]. However, the authors suggested that recombination events and in situ gene replacements by interspecies gene transfer had produced PXD101 considerable diversity in both gene composition and operonic organisation in the pathways. In light of these findings the question arises as to whether the conserved catabolic function of the PACoA catabolon is subject to varied, host dependent regulatory influences in differing species. Elucidation of such host regulatory

influences may identify key flux control points for recombinant strain engineering strategies to optimise biotechnological outputs related to the pathways [9, 16–18]. In this study the Pseudomonas putida CA-3 genome was randomly mutagenised Thymidine kinase with a mini-Tn5 transposon and isolates screened for altered styrene and phenylacetic acid utilisation phenotypes in an effort to identify key regulatory influences acting on these catabolic pathways in this strain. Figure 1 Over view of styrene catabolism. Summary schematic of the major steps in styrene and phenylacetic acid degradation. Gene clusters have been grouped broadly in relation to function, while the arrows reflect common operons observed in Pseudomonads. However, it should be noted that PF-01367338 chemical structure significant variation in PaCoA catabolon gene organisation is seen in nature, such that a standard consensus schematic is not possible.

The developed sensors would be useful at lower phenyl hydrazine concentration [10–14]. By comparing with

reported literature, composite nanorod-based phenyl hydrazine sensor was found to be more sensitive (Table 1). Composite nanorods illustrated drastically elevated sensitivity and lower detection limit as compared to earlier reported phenyl hydrazine sensors [17, 20, 21]. Consequently, the composite nanorods are excellent aspirant for the development of competent and most sensitive phenyl hydrazine sensor. Table 1 Comparison 17-AAG cell line between the sensitivity of composite nanorod sensor and literature Electrode materials Sensitivity (μA.cm−2.μM−1) Reference Composite nanorods 1.5823 Present work Al/ZnO 1.143 [17] Carbon nanotube 0.03 [20] Ferrocene and carbon nanotubes 0.0389 [21] Conclusions selleck kinase inhibitor In summary, composite nanorods were synthesized by a simple and low-temperature hydrothermal process. The detailed morphology of the synthesized composite nanorods

was characterized by XRD, FESEM, FT-IR, XPS, and UV–vis spectra and reveals that the synthesized composite is well-crystalline optically active nanorods selleck chemicals containing Ag, Ag2O3, and ZnO. The synthesized composite nanorods were applied for the detection and quantification of phenyl hydrazine in liquid phase. The performance of the developed phenyl hydrazine sensor was excellent in terms of sensitivity, detection Tryptophan synthase limit, linear dynamic ranges, and response time. Since synthesized composite nanorods have very simple synthetic procedure, low cost, and high sensitivity for phenyl hydrazine sensing, therefore, it is concluded that chemical sensing properties of composite nanorods are of great importance for the application of composite nanorods as a chemical sensor. Acknowledgments The authors would like to acknowledge the support of the Ministry of Higher Education, Kingdom of Saudi Arabia, for this research through a grant (PCSED-014-12) under the Promising Centre for Sensors and

Electronic Devices (PCSED) at Najran University, Kingdom of Saudi Arabia. References 1. Jamal A, Rahman MM, Khan SB, Faisal M, Akhtar K, Rub MA, Asiri AM, Al-Youbi AO: Cobalt doped antimony oxide nano-particles based chemical sensor and photo-catalyst for environmental pollutants. App Surf Sci 2012, 261:52–58.CrossRef 2. Khan SB, Rahman MM, Jang ES, Akhtar K, Han H: Special susceptive aqueous ammonia chemi-sensor: extended applications of novel UV-curable polyurethane-clay nanohybrid. Talanta 2011, 84:1005–1010.CrossRef 3. Faisal M, Khan SB, Rahman MM, Jamal A, Umar A: Ethanol chemi-sensor: evaluation of structural, optical and sensing properties of CuO nanosheets. Mater Lett 2011, 65:1400–1403.CrossRef 4. Jain RK, Kapur M, Labana S, Lal B, Sharma PM, Bhattacharya D, Thakur IS: Microbial diversity: application of microorganisms for the biodegradation of xenobiotics. Curr Sci 2005, 89:101–112. 5.

However, when amino acid sequence alignment

analysis was carried out, the putative cadF (-like) ORFs from all 17 C. lari isolates examined in the present study showed amino acid residues of FALG (50% identity) within the amino acid positions 137 – 140, instead of the FRLS residues (Figure 4). No FRLS residues were also detected within any other regions of the cadF (-like) ORF from all 17 C. lari isolates examined. Interestingly, FNLG residues within AdpB (Ad-adhesin in p-Prevotella, B-second identified AR-13324 solubility dmso adhesin) in Prevotella intermedia (a black-pigmented gram-negative anaerobe) [32] was 75% identical to the FALG from C. lari (Figure 4). Therefore, it may be important to clarify if the CadF (-like) protein from C. lari isolates can bind to fibronectin or not. An experiment is now in progress to resolve this. In the present study, for the first time, we have described the cloning, BMS202 sequencing and characterization of full-length Cla_0387 from the 16 C. lari isolates. The CMW values were estimated to be 23,689 – 23,875 Da

for the 16 C. lari isolates and C. lari RM2100 strain and these values were also equivalent to those from two C. jejuni and a C. coli reference strains (Table 2). In addition, the cadF (-like) gene and the Cla_0387 gene may possibly be functional within C. lari isolates, based on the present northern blot hybridization and RT-PCR observations, as shown in Figure 2A and 2B. Thus, the cadF (-like) gene and the Cla_0387 gene could be co-transcribed within C. lari organisms, consisting of an operon.

Since the Cla_0387 showed a high deduced amino acid sequence similarity to the Escherichia coli haloacid dehalogenase-like phosphatase [33], these two may have an important biological relationship within the C. lari cells. In the present study, the authors designed two novel primer pairs (f-/r-cadF1 and f-/r-cadF2) in silico for amplification of an approximate 2.3 kbp region, including the full-length cadF (-like) gene and its adjacent genetic loci, based on sequence Temozolomide information of C. lari RM2100, C. jejuni RM1221 and C. coli RM2228 strains, resulting in successful Tau-protein kinase amplification, TA-cloning and sequencing of those from the 16 C. lari isolates isolated from differencet sources and in several countries. Therefore, the present novel PCR primer pairs would be likely of value for, C. jejuni and C. coli organisms, as well as for other C. lari isolates. A dendrogram showing phylogenetic relationships was constructed by the NJ method [29], based on nucleotide sequence information of full-length cadF (-like) gene from 16 C. lari isolates and C. lari RM2100 and other thermophilic Campylobacter reference strains. As shown in Figure 5, the 17 C. lari isolates form a major cluster separating from the other three thermophilic Campylobacter spp. In addition, the 17 C. lari isolates form some minor clusters, respectively, based on nucleotide sequence information from cadF (-like) gene (Figure 5).

5 fold change threshold). The detachment phenotype of nine mutant strains was characterized using visual inspection (recorded with a digital camera), cryosections of 3 h biofilms, and SEM of the surface after draining the tubing. With slight variations, all the mutant strains exhibited detachment phenotypes that were quite similar. Figure 10 presents a panel of results for six of the strains tested. In the top row are mutants exhibiting detachment phenotypes that we consider essentially identical. The detachment phenotypes of the aqy1/aqy1 and MK5108 cost ywp1/ywp1mutants and the orf19.822 double knockout were very PRT062607 manufacturer similar to those shown in the top row.

The macroscopic appearance of the psa2/psa2 mutant was similar to the reference strain but the biofilm was too fragile to withstand the application of the OCT polymer to the surface so cryosections could not be obtained. In the bottom row are detachment phenotypes that exhibited slight variations. Cryosections of the pga13/pga13 mutant did not produce hyphae that were clearly aligned at both edges of the

biofilm. We tentatively attribute this to disruption of the structure during application of the OCT polymer since this biofilm had the appearance selleck screening library of being more fragile than that of the reference strain. In contrast, the mkc1/mkc1 mutant produced a biofilm in which alignment of hyphae appeared to be more pronounced than in the reference strain. (The detachment phenotype of the CAI4 reference strain was the same as the BWP1 reference strain). The detachment phenotype of ACT1-ALS3

biofilm was the only one that differed appreciably from the reference strain in terms of macroscopic appearance. Compared to the reference strain this mutant exhibited fewer regions of detachment that were relatively more displaced from the surface. Figure 10 Detachment phenotypes of selected mutants. All data presented are for 3 h biofilms. The top row of panels in each set are digital camera images (top view, first row; side view, second row). The third row in each set are cryosections and the forth row are SEM images of the surface after draining the tubing. SEM images PAK6 show the most densely colonized regions of the surface that could be found. The biofilm formed from the pga13/pga13 mutant was relatively fragile and this may have contributed to the altered structure of the cryosections. In terms of gross structure the most pronounced differences were seen in the ACT1-ALS3 construct which exhibited fewer regions of detachment that were relatively more displaced from the surface. Discussion Although circumstantial evidence strongly implicates that detachment from C.

Algae 2005,20(3):239–249.CrossRef 27. Kim GH, Klotchkova TA, West JA: From protoplasm to swarmer: regeneration of protoplasts from disintegrated cells of the multicellular marine green alga Microdictyon umbilicatum (Chlorophyta). J Phycol 2002,38(1):174–183.CrossRef 28. Klotchkova TA, Chah OK, West JA, Kim GH: Cytochemical and ultrastructural studies on protoplast formation from disintegrated cells of the marine alga Chaetomorpha aerea (Chlorophyta). Eur J Phycol 2003,38(3):205–216.CrossRef 29. Kim GH, Klochkova TA, Yoon KS, Song YS, Lee KP: Purification and characterization

of a lectin, Bryohealin, involved AZD0156 in the protplast formation of a marine green alga Bryopsis plumosa (Chlorophyta). J Phycol 2006,42(1):86–95.CrossRef 30. Yoon KS, Lee KP, Klochkova TA, Kim GH: Molecular characterization of the lectin, bryohealin, involved in protoplast regeneration of the marine alga Bryopsis plumosa (Chlorophyta). J Phycol 2008,44(1):103–112.CrossRef 31. Muller WE, Zahn RK, Kurelec B, Lucu C, Muller I, Uhlenbruck G: Lectin, a possible basis for symbiosis between

bacteria and sponges. J Bacteriol 1981,145(1):548–558.PubMed 32. De Hoff P, Brill L, Hirsch A: Plant lectins: the ties that bind in root symbiosis and plant defense. Mol Genet Genomics 2009,282(1):1–15.PubMedCrossRef PI3K inhibitor Authors’ contributions JH designed the experiments, analysed the data and wrote the paper. FL maintained the algal cultures. JH and HD performed the experiments. FL, ODC and AW conceived the study and helped to draft the manuscript. All authors read and approved Molecular motor the final manuscript.”
“Background

The integron includes a site-specific recombination system that integrates and expresses genes present on mobile elements called gene cassettes [1]. The integron platform is defined by three characteristics: an integrase gene (intI) whose product encodes a site-specific integrase, IntI, an attachment site (attI) at which point DNA sequences are inserted and a promoter (Pc) which expresses genes within the gene cassettes inserted at attI [2]. Gene cassettes can be inserted into the integron as individual units but multiple events can lead to large tandem arrays. Integrons are best known for their role in the spread of antibiotic resistance genes in clinical environments [3]. These clinical integrons harbour 1-6 gene cassettes and are often associated with mobile elements such as resistance plasmids and transposons [3]. However, integrons are diverse genetic elements found in approximately 10% of environmental bacteria [2]. In these bacteria, integrons are found in chromosomal locations and rarely carry antibiotic resistance gene cassettes indicating a general role in evolution. Vibrio is a genus of highly adaptable bacteria found in diverse marine-associated learn more niches [4].

(b) M-H curves for the WS2 nanosheets measured at different temperatures, where the diamagnetic signal has been deduced. (c) The FC and ZFC curves for the WS2 nanosheets. Recently, similar ferromagnetic nature was also observed in other layered materials, like graphene, graphene nanoribbons, and MoS2. Matte et al. and Enoki et al. proposed that edge states as well as adsorbed species

affect the magnetic properties of graphene [25, 26]. Zhang et al. prepared MoS2 samples with high density of prismatic edges and showed them to be ferromagnetic at room temperature, where the magnetism arising from nonstoichiometry of the unsaturated Mo and S atoms at the edge [27]. Our previous results indicate that the saturation magnetizations of the exfoliated MoS2 nanosheets increase as the lateral size decreases, revealing the edge-related ferromagnetism [22]. Density functional calculations on inorganic analog of graphite MoS2 reveal that edge

AMN-107 mouse states are magnetic and it appears that magnetism originates at the sulfur-terminated edges due to the splitting of metallic edge states at the Fermi level [28]. Besides, calculation results indicate that only MoS2-triple vacancy created in a single-layer MoS2 can give rise to a net magnetic moment [29]. Shidpour et al. indicated that a vacancy on the S-edge with 50% coverage intensifies the magnetization of the edge of the MoS2 nanoribbon, but such Emricasan manufacturer a vacancy on S-edge with 100% coverage causes this magnetic property to disappear [30]. Furthermore, MoS2 and WS2 clusters (Mo6S12 and W6S12) were shown to be magnetic, where the magnetism arising from the unsaturated central metal atom is due to

partially filled d orbitals [18]. In our case, the WS2 nanosheets with 2 ~ 8 layers thick and the presence of the high density of edges can be seen from the images in Figure 2f. The bends in the layers may arise from the defects. Besides, the high-resolution TEM FER image of the nanosheets shown in Figure 2d reveals a hexagonal arrangement of atoms with zigzag edges. Such defective centers and edges would be associated with the W atoms, which are undercoordinated, resulting in partially filled d orbitals. A high concentration of such edges and defects in our samples could be one of the Gemcitabine possible reasons for the observation of ferromagnetism. Conclusions In summary, even though the observed ferromagnetism in WS2 is in the bulk limit, results indicate that the ferromagnetism for exfoliated WS2 nanosheets persists from 10 K to room temperature. We attribute the existence of ferromagnetism partly to the zigzag edges and the defects in our samples. This unusual room-temperature ferromagnetism, which is an intrinsic feature similar to that observed in carbon-based materials, may open perspectives for spintronic devices in the future. Acknowledgements This work is supported by the National Basic Research Program of China (grant no. 2012CB933101), NSFC (grant nos.

05). (B) Genetic map of genes (open arrows) coding see more stm3169 within Salmonella-specific JPH203 supplier locus (gray arrows) and genes flanking the locus (closed arrows). Figure 5 STM3169 is a novel virulence protein. Competitive index was determined at 48 h after infection in the spleen (A). Effects of stm3169 disruption on the invasion (B) and the intracellular survival

(C) in the mouse macrophage cell lines, RAW264.7. Cells treated with IFN-γ were infected with S. Typhimurium wild-type and the mutant strains at a multiplicity of infection of 1. At 2 h and 24 h after infection, macrophages were lysed and the bacterial number was determined. Asterisks indicate that differences were statistically significant (P < 0.05). Because it is believed that intracellular Salmonella is likely to be restricted to the acquisition of nutrient substrates from infected host cells, the stringent response could occur in SCV. Thus, we next analyzed the contribution of STM3169 to intracellular survival of S. Typhimurium in macrophages. In accordance with previous data that a ppGpp0 mutant strain deficient in both spoT and relA genes resulted in a severe reduction of intracellular proliferation and suvival [12]. In contrast to the wild-type level of invasion, intracellular survival of TH973 in RAW264.7 cells was reduced, compared with that of the wild-type strain. The reduced CFU of TH937 in IFN-γ

treated-RAW264.7 cells was not more severe than that in the ΔrelAΔspoT double mutant, ΔssaV (SH113, SPI-2 T3SS component-defected mutant), and ΔssrB (YY1, SPI-2 regulator Combretastatin A4 nmr mutant) strain,

but was equal to that in the ΔsseF (TM548, SPI-2 effector mutant) strain (Figure 5B and 5C). These results suggest that the expression of additional virulence factors, like STM3169, in macrophages might be affected in a highly avirulent phenotype of a ppGpp-deficient strain in mice. stm3169 is regulated by the SPI-2 transcriptional regulator ssrB It has been demonstrated that ppGpp mediates the expression of virulence-associated genes involved in bacterial invasion and intracellular growth selleck screening library and survival via global and/or gene-specific transcriptional regulators in S. Typhimurium [12, 14]. Since intracellular growth and suvival of Salmonella in macrophages is dependent upon SPI-2 function, we next confirmed whether expression of stm3169 is regulated by the SsrAB two-component system, which positively controls the expression of SPI-2 genes as well as other genes belonging to the SsrB regulon [32]. To test this, we constructed S. Typhimurium strains carrying stm3169::lacZ transcriptional fusions on the chromosome in the wild-type (SH100) and ΔrelAΔspoT (TM157) genetic background. Salmonella strains carrying the stm3169::lacZ fusion gene (TH1162 and TH1164) were grown in defined MgM medium (pH 5.8) with 0.1% casamino acids and measured β-galactosidase activity. The transcription levels of stm3169::lacZ fusion were significantly decreased in TM157 (Figure 6A).