Lancet 2001,357(9262):1076–1079.PubMedCrossRef 21. Niers L, Martin R, Rijkers G, Sengers F, Timmerman H, van Uden N, Smidt H, Kimpen J, Hoekstra M: The effects of selected probiotic strains on the development of eczema (the PandA study). Allergy 2009,64(9):1349–1358.PubMedCrossRef 22. Kukkonen

K, Savilahti E, Haahtela T, Juntunen-Backman K, Korpela R, Poussa T, Tuure T, Kuitunen M: Probiotics and prebiotic galacto-oligosaccharides in the prevention of allergic diseases: a randomized, double-blind, placebo-controlled trial. J Allergy Clin Immunol 2007,119(1):192–198.PubMedCrossRef 23. Wickens K, Black P, Stanley T, Mitchell E, Fitzharris P, Tannock G, Purdie G, Crane J: Probiotic study group. GSK2126458 manufacturer A differential effect of 2 probiotics in the prevention of eczema and atopy: a double-blind, randomized, placebo-controlled trial. J Allergy Clin Immunol 2008,122(4):788–794.PubMedCrossRef 24. Adlerberth I, Strachan D, Matricardi P, Ahrné S, Orfei L, selleck chemicals Aberg N, Perkin MR, Tripodi S, Hesselmar B, Saalman R, Coates AR, Bonanno CL, Panetta V, Wold AE: Gut microbiota and development

of atopic eczema in 3 European birth cohorts. J Allergy Clin Immunol 2007,120(2):343–350.PubMedCrossRef 25. Kopp M, Hennemuth I, Heinzmann A, Urbanek R: Randomized, double-blind, placebo-controlled trial of probiotics for primary Dynein prevention: no clinical effects of Lactobacillus GG supplementation. Pediatrics 2008,121(4):e850–6.PubMedCrossRef 26. Taylor A, Dunstan J, Prescott S: Probiotic supplementation for the first 6 months of life fails to reduce the risk of atopic dermatitis and increases the risk of allergen sensitization

in high-risk children: a randomized controlled trial. J Allergy Clin Immunol 2007,119(1):184–191.PubMedCrossRef 27. Zoetendal EG, Rajilic-Stojanovic M, de Vos WM: High-throughput diversity and functionality analysis of the gastrointestinal tract microbiota. Gut 2008,57(11):1605–1615.PubMedCrossRef 28. Rajiliç-Stojanoviç M, Heilig H, Molenaar D, Kajander K, Smidt H, de Vos W: Development and application of the Human Intestinal Tract Chip (HITChip), a phylogenetic microarray: absence of universally conserved phylotypes in the abundant microbiota of young and elderly adults. Environ Microbiol 2009, 11:1736–1743.PubMedCrossRef 29. Palmer C, Bik EM, Digiulio DB, Relman DA, Brown PO: Development of the human infant intestinal microbiota. PLoS One 2007,5(7):e177. 30. Paliy O, Kenche H, Abernathy F, Michail S: High-throughput quantitative analysis of the human intestinal microbiota with a phylogenetic microarray. Appl Environ Microbiol 2009,75(11):3572–3579.PubMedCrossRef 31. Yu Z, Morrison M: Improved extraction of PCR-quality community DNA from digesta and fecal samples. Biotechniques 2004,36(5):808–812.PubMed 32.

49 l (0.30 l – 0.70 l) in R1 was not sufficient to prevent dehydration, but with regards to ad libitum fluid intake, body fluid homeostasis was maintained. GDC-0941 manufacturer Since fluid intake was not related to Δ plasma volume nor to Δ plasma [Na+] in R1, the effective homeostasis must result from the buffering effect of the exchangeable osmotically inactive body sodium stores [39]. Regardless of the modest fluid consumption in all groups (R1-R4), finishers in R2, R3 and R4 were more hyperhydrated than euhydrated, and factors other than fluid intake seemed responsible for fluid regulation in ultra-athletes, such as a hormonal regulation by aldosterone [2, 19, 21, 24, 57] and inappropriate levels of the hormone

vasopressin [42, 43] and the exchangeable osmotically inactive body sodium stores [39]. Changes in body mass and prevalence in EAH An important finding of this study was that of the three participants who were hyponatremic post-race, no finisher showed an increase in body mass. Both EAH-A-R2 and EAH-B-R3 were euhydrated, while EAH-C-R4 was dehydrated as

defined by Noakes et al. [39]. Another observation from our study was that body mass decreased in all normonatremic ultra-endurance athletes (ultra-MTBers, ultra-runners and MTBers) in the 24-hour races (R1-R3), and in the multi-stage MTB race (R4). Δ body mass varied from a 6.6% loss in body mass to a 3.4% gain in body mass. EAH is more commonly associated with overhydration. In a recent study by Hoffman et al. [11], 18.5% of the finishers were dehydrated. Of those with EAH, 35.6% https://www.selleckchem.com/products/Rapamycin.html were euhydrated, and 35.6% were dehydrated. In 887 finishers of a 161-km ultramarathon, Δ body mass varied from an 8% loss to a 10% gain [11].

Top finishers in the ultra-MTBers (R1,R2) and the ultra-runners (R3) varied in Δ body mass from a 0.7% gain to a 6.6% loss and in the MTBers (R4) from a 3.4% gain in body mass to a 4.3% loss in body mass. On average, finishers in R1-R4 were euhydrated as defined by Noakes [39]. An extremely hot or cold environment is considered as a risk factor for EAH [12, 40], however we found no relationship Docetaxel supplier between the prevalence of EAH and the ambient temperature in the present study. The 24-hour MTB race (R1) was held in a warm weather with low humidity during the whole race and the multi-stage race (R4) was held in typical hot summer weather, however with higher humidity (Table 1). The 24-hour MTB race (R2) was in more variable weather conditions with some precipitations, higher temperature fluctuations and high humidity (Table 1). The 24-h running race (R3) was held in colder weather with heavy precipitations compared with races R1, R2 or R4. In a recent study with 887 observations of weight change in a 161-km running race, Hoffman et al. [11] found significant correlations for percentage Δ body mass and percentage of dehydrated runners with ambient temperature.

LSplex selleck kinase inhibitor would amplify selectively the underrepresented bacterial DNA. The large set of primer pairs is potentially able to amplify as many gene segments as probes are immobilized on the prototype microarray but in practice, it is supposed to only amplify the gene-segments specific to the pathogens present in the analyte.

In parallel, real-time PCR-based assays for identification of pathogens were proposed since the sensitivity is adequate for direct detection and quantification [10–12, 40–43]. However, the information level obtained by this approach is incomparably lower than the one provided by medium or high density microarray analyses. Real-time PCR has a reduced potential for multiplexing because the current availability of only four to five channels for the simultaneous non-overlapping detection of different fluorophores [21]. For this reason, real-time PCR is in general confined to a mere species identification based on single sequence polymorphism [10, 43] or to confirm the presence of a suspected pathogen by using a reduced number of specific primer pairs [44, 45] eventually completed by the detection of a few genes related to antibiotic resistance [46, 45]. In contrast, microarrays offer the possibility to profile pathogens by providing information at the strain level [36],

by detecting virulence factors and genes determining the antibiotic resistance [16]. The LSplex amplification protocol is a promising co-adjuvant for pathogen MLN0128 purchase profiling by microarray analysis since it increases sensitivity and the specificity

of detection. It also presents the flexibility of using hundreds of primer pairs, whose sequences Adenosine are exchangeable in function of the pathogens targeted in the microarray. The single-step LSplex protocol, allowing labelling during amplification, could represent one piece of the methodological mosaic in a future time-saving bacteriological diagnostic approach. Acknowledgements We are grateful to Georg Plum and Paul Higgins for helpful comments on the manuscript. This work was supported by the DFG, the DFG Gottfried-Wilhelm-Leibniz-Program, the GEW Stiftung, Cologne, Germany and Köln Fortune. Electronic supplementary material Additional file 1: Microarray probes and primer sequences. The table contains the description of microarray probes and primer sequences used in the study. (PDF 73 KB) Additional file 2: Prototype DNA microarray for detection of common pathogens. The figure represents the analysis of microarray hybridizations with decreasing amounts of bacterial DNA. (PDF 602 KB) References 1. Cho JC, Tiedje JM: Quantitative detection of microbial genes by using DNA microarrays. Appl Environ Microbiol 2002, 68:1425–1430.CrossRefPubMed 2. Cleven BE, Palka-Santini M, Gielen J, Meembor S, Krönke M, Krut O: Identification and characterization of bacterial pathogens causing bloodstream infections by DNA microarray. J Clin Microbiol 2006, 44:2389–2397.CrossRefPubMed 3.

Furthermore, this miRNA was also found to be involved in multi drug resistance [44]. There are a few limitations of the current study that have to be considered for proper interpretation of our results. Firstly, the current study represents an in-vitro study with only one esophageal adenocarcinoma and one squamous cell carcinoma cell line. This means that our data cannot be immediately transferred into clinical settings,

as results might be limited to the selected cell lines and reproducibility might be limited. However, this is the first study that investigates BMN 673 research buy the effect of PPI treatment on esophageal cancer, and we selected well known and commonly used esophageal cancer cell lines. Therefore, in our opinion this data provides a valid basis for further investigations in additional in-vitro or in-vivo experiments. Secondly, we used esomeprazole doses of up to 250 μM in our experiments. In this context, maximal tissue concentrations after esomeprazole administration in humans have to be considered in order to achieve clinically relevant data on the effect of esomeprazole on tumour characteristics. Based on product information from Astra Zeneca, 40 mg i.v. esomeprazole (which is the standard dose of esomprazole per day in the therapy of peptic HIF pathway ulcer and gastritis) would achieve a steady state tissue concentration

of 6 μM for an 80 kg human. However, in specific situations such as hypersecretory conditions, recommended adult oral starting dose of esopmeprazole is 60 mg once daily with subsequent adjustment of individual doses, and doses up to 120 mg three times daily have been administered. cAMP The doses used in our experiments are higher than the currently clinically used doses. However, PPIs are considered to be generally safe in application. Despite some reported adverse side effects such as osteoporosis and bone fracture, hypomagnesaemia, the development of gastric polyps, enteric infections, interstitial nephritis and pneumonia, and the absolute risk of complications attributed to PPIs is low [45]. Moreover,

the doses used in our experiments are similar to those of other research groups [14]. Thirdly, we did not include an analysis of the expression pattern of proton pumps in the cell membrane or in membranes of intracellular vesicles, or of the exact percentage and strength of inhibition of the proton pumps via esomeprazole. We only analysed the intra- and extracellular pH and concluded from these data that both cell lines were still able to excrete protons into the extracellular space. However, as several other authors observed that PPI treatment lead to intracellular acidification, in our opinion the absence of this accumulation of protons in the intracellular space in our experiments justifies the conclusion that this is not the main effect of action of esomeprazole in esophageal cancer cell lines.

Relative growth (% Survival) was determined by dividing the CFUs obtained from treated cultures by the

CFUs from cultures without antibiotic. To titrate OMV-mediated protection, OMVs and antimicrobials were co-incubated in 5 mL LB (2 h, 37°C) at the indicated MG-132 in vitro concentrations. The mixture was centrifuged (38,400 g, 1 h), and the supernatant (OMV-pretreated media) transferred to a new tube. Meanwhile, cultures of WT or ETEC E. coli (5 mL) were grown to OD600 0.45, centrifuged (4100 g, 10 min), and the media was removed. The cell pellets were then resuspended to their original culture volume (5 mL) with OMV-pretreated media, incubated (2 h, 200 rpm, 37°C), and dilution-plated on LB agar plates (containing kanamycin for WT, not ETEC, cultures) to determine CFU/mL. Relative growth (% Survival) was determined by dividing the CFUs obtained from treated cultures by the CFUs from cultures without antibiotic. Alkaline phosphatase cell integrity assay E. coli MK318 cultures were treated for 2 h with 0.75 μg/mL polymyxin B, or 0.5 μg/mL colistin. A portion of the treated and untreated cultures was dilution-plated for CFU/mL determination. Following the treatment, cells were pelleted (4,100 g, 10 min, 4°C), and the supernatant

was cleared of OMVs (38,400 g, 2 h, 4°C). AP was detected in 150 μL samples of OMV-free Selumetinib in vivo supernatant (S) and the whole cell pellets (WC) using the Anaspec Sensolyte pNPP alkaline phosphatase assay kit per the

manufacturer’s instructions. Doxorubicin in vivo Briefly, 50 μl of sample was applied in duplicate to each well of a 96-well plate (Corning), then 50 μl of pNPP substrate solution was added. Absorbance at 405 nm was measured (Fluostar Optima) after 2 h. AP concentrations in samples were derived using a standard curve generated using known concentrations of AP. The ratios of AP in the OMV-free supernatant compared to the whole cells (S/WC) were then normalized to the CFU/mL in the original cultures. Polymyxin B resistance plate assay To assess the time-course of the acquisition of adaptive polymyxin B resistance, the procedure described for the OMV protection assay was used, except that following the indicated treatment of the ETEC cultures with ETEC OMVs and polymyxin B, polymyxin B alone, or LB alone, cultures were streaked on LB agar and LB agar containing 5 μg/ml of polymyxin B with a sterile applicator at 1 h intervals for up to 7 h. T4 titration T4 D+ phage titering was assessed using MK496 as the host strain. Several 10-fold dilutions of a high-concentration lysate were made, 100 μL of each of these dilutions was then combined with 100 μL of MK496 for 5 min, the 200 μL samples were then added to warmed (55°C) top agar (Bactotryptone 13 g/L, NaCl 8 g/L, Na-Citrate-2H2O 2 g/L, Glucose 3 g/L, and Bactoagar 6.

cremoris

SK11 reveal extensive adaptation to the dairy environment. Appl Environ Microbiol 2005,71(12):8371–8382.PubMedCrossRef 15. Rademaker JL, Herbet H, Starrenburg MJ, Naser SM, Gevers D, Kelly WJ, Hugenholtz J, Swings J, van Hylckama Vlieg JE: Diversity analysis of dairy and nondairy Lactococcus lactis isolates, using a novel multilocus sequence analysis scheme and (GTG)5-PCR fingerprinting. Appl Environ Microbiol 2007,73(22):7128–7137.PubMedCrossRef 16. Siezen RJ, Bayjanov JR, Felis GE, van der Sijde MR, Starrenburg M, Molenaar D, Wels M, van Hijum SA, van Hylckama Vlieg JE: Genome-scale diversity and niche adaptation analysis of Lactococcus lactis by comparative genome hybridization using multi-strain arrays. Microb

Biotechnol 2011,4(3):383–402.PubMedCrossRef ABC294640 order 17. Taibi A, Dabour N, Lamoureux M, Roy D, LaPointe G: Evaluation of the genetic polymorphism among Lactococcus lactis subsp. cremoris strains using comparative genomic hybridization and multilocus sequence analysis. Int J Food Microbiol 2010,144(1):20–28.PubMedCrossRef 18. Passerini D, Beltramo C, Coddeville M, Quentin Y, Ritzenthaler P, Daveran-Mingot ML, Le Bourgeois P: Genes but not genomes reveal bacterial domestication of Lactococcus lactis . PLoS One 2010,5(12):e15306.PubMedCrossRef 19. Nieto-Arribas P, Sesena S, Poveda JM, Palop L, Cabezas L: Genotypic and technological characterization of Lactococcus lactis isolates involved in selleck chemical processing of artisanal Manchego cheese. J Appl Microbiol 2009,107(5):1505–1517.PubMedCrossRef 20. Psoni L, Kotzamanidis C, Yiangou M, Tzanetakis N, Litopoulou-Tzanetaki E: Genotypic and phenotypic diversity of Lactococcus lactis ADAMTS5 isolates from Batzos, a Greek PDO raw goat milk cheese. Int J Food Microbiol 2007,114(2):211–220.PubMedCrossRef 21. Tan-a-ram P, Cardoso T, Daveran-Mingot ML, Kanchanatawee S, Loubiere P, Girbal L, Cocaign-Bousquet M: Assessment of the diversity of dairy Lactococcus lactis subsp. lactis isolates by an integrated approach combining phenotypic, genomic, and transcriptomic analyses. Appl Environ Microbiol

2011,77(3):739–748.PubMedCrossRef 22. Bayjanov JR, Molenaar D, Tzeneva V, Siezen RJ, van Hijum SA: PhenoLink – a web-tool for linking phenotype to omics data for bacteria: application to gene-trait matching for Lactobacillus plantarum strains. BMC Genomics 2012, 13:170.PubMedCrossRef 23. Rauch PJ, De Vos WM: Characterization of the novel nisin-sucrose conjugative transposon Tn5276 and its insertion in Lactococcus lactis . J Bacteriol 1992,174(4):1280–1287.PubMed 24. Rauch PJ, Beerthuyzen MM, de Vos WM: Distribution and evolution of nisin-sucrose elements in Lactococcus lactis . Appl Environ Microbiol 1994,60(6):1798–1804.PubMed 25. Kelly WJ, Davey GP, Ward LJ: Characterization of lactococci isolated from minimally processed fresh fruit and vegetables. Int J Food Microbiol 1998,45(2):85–92.PubMedCrossRef 26.

K38 cells expressing the wild-type gp9 from the plasmid (B) showed plaque formation at the 105-fold dilution, similar to the suppressor cells K37 (H). When no IPTG was added to the plate plaque formation was reduced (C). Cells expressing the modified gp9 proteins all showed efficient plaque formation. Gp9-T7 (D), gp9-HA (E), gp9-DT7 (F) and gp9-DHA (G) were analysed. Expression of the modified gp9 protein in E. coli The plasmid-encoded gp9 variants were analysed for expression in E. coli K38. The cells were grown

at 37°C to the early exponential phase in M9 minimal medium. Protein expression was induced by adding 1 mM IPTG and after 10 min the newly synthesised proteins were pulse-labelled for 10 min with 35S-methionine. The total bacterial Ibrutinib manufacturer proteins were TCA precipitated to remove the non-incorporated 35S-methionine and immunoprecipitated using an antiserum to the T7 tag or to the HA tag, respectively (Figure 4). Since gp9 is a very small protein of 32 amino acids containing only two methionines the protein band on a SDS tricine PAGE is difficult to visualise. When comparing the protein pattern of cells expressing gp9-T7 (lane selleck chemicals 3) with cells containing

the empty plasmid (lane 2) a protein band of about 5.5 kDa was observed. Also a weak band of gp9-HA (lane 4) was visible on the gel. The size of the protein was estimated in relation of the major coat protein gp8 shown in lane 1. Since the 50 amino acid residues long gp8 has a molecular weight of 5.2 kDa, the gp9-T7 with 51 residues and gp9-HA with 49 residues are proteins of very similar molecular weight. Figure 4 Expression of gp9-T7 from a plasmid. Exponentially growing E. coli K38 cells bearing a plasmid encoding M13 gp8 (lane 1), the empty pMS plasmid (lane 2), pMS-g9-T7 (lane 3) and pMS-g9-HA (lane 4), respectively, were induced for 10 min with IPTG and pulse-labelled with 35S-methionine for 10

min. The proteins were precipitated with trichloroacetic acid (TCA) and immunoprecipitated with antiserum to ifoxetine gp8 (lane 1), to T7 (lane 2, 3) and to HA (lane 4), respectively. SDS tricine PAGE was used to separate the proteins and the radioactivity was visualised by phosphorimaging. Membrane insertion of gp9-T7 The membrane insertion of gp9 with the N-terminal T7 tag was analysed in E. coli K38 cells bearing the pMS-g9-T7 plasmid. The gp9-T7 protein was expressed as described above. The cells were converted to spheroplasts and analysed by protease mapping (Figure 5A). The protein immunoprecipitated with antiserum to the T7 tag was readily digested by proteinase K added to the outside of the spheroplasts (lane 2). This suggests that the antigenic tag of gp9 was accessible to the protease at the periplasmic surface, whereas the cytoplasmic GroEL protein was protected from digestion (lane 4). Further, the periplasmic portion of the OmpA protein was digested by the proteinase K (lane 6) confirming the proteolytic activity.

Genes Immun 2011, 12:280–290.PubMedCrossRef Competing interests The authors declare that they have no competing interests. Authors’ contributions GR, ST, ETA and LCMA carried out Salmonella infections. GR performed the gene expression analysis, western blots and immunofluorescent microscopy. SC and ETA performed the cholesterol and triglyceride determinations. MTC carried out the Listeria infections. BBF participated in the supervision of the study. GR and AM drafted the manuscript. AM conceived the study and supervised its design, coordination and execution. All authors read and approved

the final manuscript.”
“Background β-Galactosidases (EC 3.2.1.23), which hydrolyze lactose to glucose and galactose, have two main applications in food industry, including production of low-lactose milk and dairy products p38 MAPK inhibitor for lactose intolerant people and production of galacto-oligosaccharides from lactose by the

transgalactosylation reaction [1]. Traditionally, commercial β-galactosidases this website are produced from fungi of the genus Aspergillus and yeasts of the genus Kluyveromyces[2]. Despite these β-galactosidases have outstanding lactose hydrolysis ability, they have two major drawbacks including low thermostability and high inhibition of reaction products. Commonly, the optimum termperatures of these enzymes are less than 58°C [3, 4], and thus they have low stability during the high-temperature (65–85°C) pasteurization of milk. Furthermore, Bay 11-7085 these enzymes are badly inhibited in the presence of the reaction products (galactose and glucose) [5, 6], and the inhibition of reaction products may lead a decrease in the reaction rates or even stop enzymatic reaction completely. These two problems can be solved using thermostable β-galactosidases with high tolerance of galactose and glucose. Therefore, interests in identifying novel β-galactosidases with high thermostablility

or high tolerance of galactose and glucose have been increasing in the last decade. Despite some thermostable β-galactosidases have been found from thermophilic microorganisms [7–13], and several β-galactosidases from mesophilic microorganisms with high tolerance of galactose or glucose have also been identified [13–15], the β-galactosidases possessing simultaneously high thermostablity and tolerance of galactose and glucose are still seldom reported until now. Furthermore, almost all of reported β-galactosidases are from cultured microorganisms, and little attention has been paid to β-galactosidases from unculturable microorganisms, which account for over 99% of microorganisms in the environment [16]. Therefore, some efforts should be made to discover novel β-galactosidases with high thermostability and tolerance to reaction products from unculturable microorganisms of environment.

044 × isometric strength) + (0.137 × concentric strength) + (-0.049 × eccentric strength) + 4.074, r = 0.451, p = 0.002. Indeed IL-6 was not a good predictor of RPE scale. Discussion Evidence from clinical and experimental studies suggests that omega-3 has a protective effect against cancer-induced cachexia, ageing-related chronic inflammation and other inflammatory diseases associated with excessive levels of cytokines [17]. This has led to further research to investigate whether EPA can have the same

positive response on pro-inflammatory cytokines and symptoms associated with DOMS following exercise. Phillips et al. [20] and Bloomer et al. [21] both provided evidence LDE225 to support the earlier in vivo and in vitro work [18, 19], although both studies only observed the initial acute response after a single bout of exercise. These studies provided the basis for the current study in an attempt to observe if a dose of EPA which is twice the daily recommended level (i.e.

~2 × 180 mg per day) would inhibit acute and chronic IL-6 mediated inflammation, muscle soreness and RFGC following resistance exercise. The findings from the present study suggest that after three weeks of treatment, the standard dose of EPA may not be beneficial in ameliorating the symptoms associated with DOMS and IL-6 mediated inflammation response to exercise. In fact, the data would suggest that whereas strength and pain sensations related to resistance exercise are no different with/without EPA, exercise-induced IL-6 levels are in fact significantly elevated following three weeks PS-341 mw of daily intake of EPA. Babcock et al. [29] previously suggested two possible mechanisms that

may be responsible for the anti-inflammatory ability of EPA. An initial response is for the EPA to be readily incorporated into the cellular membrane, where it alters linolenic and linoleic acids, which are essential for the production of arachidonic acid, the latter which is in fact involved in pain and inflammation. This was based on the earlier findings of Endres et al. [30], who looked at inflammation at a more cellular level in humans and rodents. They demonstrated that once within the cellular membrane, PRKD3 inflammation is affected by reducing prostaglandin E2 (PGE2) levels. Additionally a further mechanism was demonstrated by Lo et al. [31], who indicated that EPA modulates inflammation at a molecular level by down regulating the ubiquitin-proteasome proteolytic pathway, through decreasing translocation of nuclear factor-κb (NFκb). The authors indicated that EPA possesses the ability to reduce NFκb, which is involved in protein degradation. A reduction in NFκb would enable a positive environment for protein synthesis for repair of muscle following exercise, rather than a catabolic one.

The RecBCD pathway is important in conjugational and transductional recombination [39], and may also be involved in the recombination of plasmids containing one or more Chi sites [40]. Recombination in small plasmids lacking a Chi sequence is primarily catalyzed by the RecFOR pathway [41]. RecF, RecO, and RecR bind to gaps of ssDNA and displace the single-strand DNA binding proteins to allow RecA to bind [42, 43]. The RecJ ssDNA exonuclease acts in concert with RecFOR to enlarge the ssDNA region when needed. Strand exchange is then catalyzed by RecA [44]. Because of

their prominent role in plasmid recombination in E. coli, we analyzed the effect of mutations in recF, recJ and recA on plasmid Venetoclax manufacturer recombination in Salmonella. Attenuated S. Typhi strains have been developed as antigen delivery vectors for human vaccine use. Due to the host restriction phenotype of S. Typhi, preliminary work is typically done in S. Typhimurium MK 1775 using mice as the model system to work out attenuation and antigen expression strategies. Recently, we have also been investigating attenuated derivatives of the host-restricted strain S. Paratyphi A as a human vaccine vector. Therefore, it was

of interest to evaluate and compare the effects of rec mutations in these three Salmonella serovars. We selected S. Typhi strain Ty2 as exemplary of this serovar because most of the vaccines tested in clinical trials to date have been derived from Ribose-5-phosphate isomerase this strain [45]. S. Typhi strain ISP1820 has also been evaluated in clinical trials [46, 47] and we therefore included it in some of our analyses. We found that, for some DNA substrates, the effects of ΔrecA and ΔrecF deletion mutations differed among Salmonella enterica serotypes. In particular,

we found that deleting recA, recF or recJ in S. Typhi Ty2 and deleting recF in strain ISP1820 had significant effects (3-10 fold) on the recombination frequency of our direct repeat substrate, pYA4463 (Table 3). No or very limited effect (< 2 fold) was observed for our S. Typhimurium and S. Paratyphi A strains, consistent with results reported for E. coli indicating that recombination of this type of substrate is recA-independent [35]. In contrast, the ΔrecA and ΔrecF mutations resulted in lower interplasmid recombination in Typhimurium and Paratyphi A but not in Typhi strains. Deletion of recJ led to a reduction in intraplasmid recombination frequencies in S. Typhi, while no effect was seen in S. Typhimurium. The ΔrecJ mutation also affected plasmid recombination frequencies for two of the three substrates tested in S. Paratyphi A. Taken together, these results suggest that the recombination system in S. Typhi, or at least in strains Ty2 and ISP1820, is not identical to the recombination system in S. Typhimurium and S. Paratyphi A.