A wax block was positioned between the rats’ heads and a 0.5 cm tissue equivalent bolus was placed on top to ensure full build

up of the dose at the skin surface. A dose of 15 Gy selleck compound was prescribed at a 1.5 cm depth and delivered at a dose rate of 200 cGy/min (treatment planning system: Dosigray, DosiSoft, Cachan, France). After irradiations were completed, the animals were transferred to the Animal Care Facility at the ESRF. These irradiation parameters were chosen to be as close as possible to the Stereotactic synchrotron radiotherapy carried out at the European Synchrotron Radiation Facility (ESRF), which was previously described [12]. Tumor imaging To confirm the presence of tumor, contrast-enhanced imaging was performed after radiotherapy using a conventional CT scanner (Siemens Somatom Plus 4 Volume Zoom scanner, Siemens Medical Systems, Iselin, NJ, USA). All of the animals received an intravenous (i.v.) injection of 1.5 mL of Iomeron® (350 mg/mL of iodine), followed by 0.5 mL of a saline solution (NaCl 0.9%) via the tail vein 10 minutes before computed tomography. Four animals showed no evidence of tumor at this time and they were excluded from the therapy studies. Statistical 10058-F4 purchase methods Kaplan-Meier survival plots were compared with the log-rank test (JMP, SAS Institute

Grégy sur-Yerres, France). The log-rank test statistic compares estimates of the hazard functions of the two groups at each observed event time. It is constructed by computing the Selleck SIS3 observed and expected number of events in one of the groups at each observed event time and then adding these to obtain an overall

summary across all time points where there is an event. The rats’survival were considered as significantly different when p < 0.05. Results Therapeutic response following i.c. of carboplatin in combination with 6 MV X-irradiation Survival data are summarized in Table 1 and Kaplan-Meier survival plots are shown in Figure 1. The survival plots of all treatment groups were significantly different from those of untreated controls (p < 0.02). Untreated rats had a mean survival time (MST) of 32 ± 2 d compared with 40 ± 3 d for 6 MV Lenvatinib clinical trial X-irradiated animals. Rats that had received carboplatin alone had a median survival time (MeST) of 52 d and a censored MST of 71 ± 7 d, with 1 rat surviving more than 180 d, at which time the study was terminated. Animals that had received carboplatin, followed by X-irradiation with 6 MV photons, had a MST of > 126 ± 8 d and a MeST of > 180 d, with 6 of 11 rats (55%) alive at the end of the study. This was significantly different from irradiated animals (p <0.01) or those that had received carboplatin alone (p = 0.07).

Thus the resistance to complement killing of these BT 1A strains must have another, unresolved mechanism. Although the potential pathogenicity of BT 1A strains remains controversial, there are a few studies that show an association to disease. For instance, BT 1A/O:6,30 was associated with spondyloarthropaties of patients in England and South-Wales [5]. Also, in a study of antibody production, it was found that a patient www.selleckchem.com/products/riociguat-bay-63-2521.html with symptoms of diarrhoea and reactive arthritis

had IgG, IgA and IgM antibodies against the BT 1A/O:6 strain isolated from her fecal sample [6]. We found symptomatic patients with isolates of both BT 1A genetic groups, but did not find statistical differences between the genetic groups and

the clinical picture of the symptoms of these patients. It may be that the patients’ genetic or other factors such as gut environment are relevant in the www.selleckchem.com/products/R406.html disease caused by BT 1A strains. Conclusions The results of our study present strong evidence that strains classified as Y. enterocolitica BT 1A represent more than one subspecies. BT 1A Genetic group 1 consisted of strains with a variety of pathogenicity-related properties, whereas all 17 strains of BT 1A Genetic group 2 lacked the ystB gene, belonged either to the same LPS subtype buy LY294002 or were rough, were all resistant to the five tested yersiniophages and were largely resistant to serum ever complement killing. Furthermore, none of them fermented fucose. Although several studies have been conducted to reveal the significance of the BT 1A strains in causing disease, indisputable results have not been obtained. This study shows, however, that BT 1A is a very heterogenous group of strains, some of which might be potential pathogens. Therefore, better understanding of the genetic and phenotypic variability and clustering of these strains, as achieved in our study, would be crucial in determining the pathogenic role of

the strains belonging to the defined clusters. Methods Bacterial strains Altogether 298 BT 1A, 75 bioserotype 4/O:3, two 3/O:3, five 2/O:9 and two non-biotypable Y. enterocolitica strains isolated in 2006 from human samples [27] were utilized in the study. Only one strain per person was included in the study. MLST sequencing MLST analysis was done on 53 Y. enterocolitica strains (43 BT 1A and 10 BT’s 2–4 strains) that represented various LPS patterns. Additionally, two reference strains, NCTC11174 (O:9) and NCTC11176 (O:3), were included in the analysis. Genomic DNA was extracted using Jetflex Genomic DNA purification kit (Genomed, Löhne, Germany). Fragments of seven house-keeping genes (adk, argA, aroA, glnA, gyrB, thrA, trpE) were amplified by PCR. For the adk, argA, aroA, glnA, thrA and trpE genes, the primers available in the MLST database for Y. pseudotuberculosis at the ERI, University College Cork, were used ( http://​mlst.​ucc.

“The new generations get educated, and they live in the towns,” an Ababda man of the Haranab clan explained. “The school education is not like the Arab traditional education. Elders who teach and give the first lessons on the desert are gone. “An Ababda of the Blalab clan added

that the educated children that live in the town “cannot live in the desert any more.” Most of our informants concur that once their kinsmen have settled down and adopted these new knowledge systems they do not return to desert life. It is remarkable that Blasticidin S mouse in recent years, many central Saharan nomads have chosen to remain in the desert explicitly because they have seen those who settle lose their desert knowledge, become poor, and find themselves unable to fall back on to the security provided by traditional knowledge and skills. Jeremy Keenan writes that “’the

failure of modernization to deliver find more on its promises’ is leading to a degree of nomadic cultural revivalism across much of the central Sahara” (Keenan 2006 p. 705). For our study area, we have only speculated whether abundant rains, the decline of tourism, political events or other variables might lead to a similar resurgence or restoration of desert-rooted livelihoods. Well informed decision making about desert development could also play a role. Conclusion Our research in a large area of the RSH reveals that tribal pastoral nomadic peoples with different ethnic and cultural roots have developed analogous ecological knowledge about how to manage their vital acacia resources with optimal efficiency. Through the generations they have passed that learning down as what we recognize as traditional ecological knowledge. This TEK has helped them to develop sustainable triclocarban indigenous resource management strategies and tactics protecting the vital services of this ecological keystone species and thereby enabling their life in the desert. These peoples have a rich body of cultural associations with acacias that also generally help to safeguard the trees. The acacia

is a cultural keystone whose see more attributes draw from and contribute to the social, spiritual and moral characteristics of people who value the tree. Acacia management has long played a central role in moulding and maintaining the cultural landscapes of the RSH. These landscapes represent an enduring and largely successful human relationship with nature. Ongoing detrimental changes affecting acacia populations in the study area correlate more strongly with social impacts than with climatic factors. Social and economic pressures on cultural and natural resources are severing the intimate bonds between nature and nomadic culture. Ongoing social and economic changes and sedentarization among nomads may have strong and lasting environmental costs. Understanding and addressing these linkages are critical challenges for social and natural scientists and policy makers.

Moreover, we demonstrated that TLR2 is partially involved in this immunoregulatory effect of L. jensenii TL2937 in PIE cells [14]. Then, we next aimed to evaluate if this immunobiotic strain has a similar effect on BIE cells. For this reason, BIE cells were stimulated for 12, 24 or 48 hours with L. jensenii TL2937 or the synthetic TLR2 agonist Pam3CSK4 and then challenged with heat-stable ETEC PAMPs. Twelve hours after CHIR98014 stimulation levels of MCP-1, IL-8 and IL-6 were evaluated

learn more (Figure 3A). Stimulation of BIE cells for 12 h with L. jensenii TL2937 or Pam3CSK4 significantly increased the production of IL-8 in response to heat-stable ETEC PAMPs challenge in hour

12 post-stimulation. On the contrary, levels of IL-8 were significantly lower in cells treated for 48 h with L. jensenii TL2937 or Pam3CSK4. MCP-1 levels were significantly higher than controls in BIE cells treated for 12 h with Pam3CSK4 or 24 h with L. jensenii TL2937 (Figure 3A). BIE cells pre-stimulated with L. jensenii TL2937 or Pam3CSK4 during 24 h showed significantly reduced levels of IL-6 (Figure 3A). Figure 3 Evaluation of the immunomodulatory activity Ruxolitinib of lactobacilli. (A) Bovine intestinal epithelial (BIE) cells were pre-treated with immunobiotic Lactobacillus jensenii TL2937 or Pam3CSK4 for 12, 24 or 48 hours, stimulated with heat-stable ETEC PAMPs and then the expression of MCP-1, ZD1839 purchase IL-6 and IL-8 was studied at hour twelve post-stimulation. Significantly different from ETEC Control *(P<0.05). (B) Levels of MCP-1 and IL-6 proteins. BIE cells were pre-treated with Lactobacillus casei OLL2768 or L. casei MEP221108 for 48 hours and the stimulated with heat-stable ETEC PAMPs and then levels of MCP-1 and IL-6 was studied at hour twelve post-stimulation. Significantly

different from ETEC Control *(P<0.05). These results indicate that it is possible to modulate the inflammatory response in BIE cells by using LAB. Then, we next aimed to evaluate the potential anti-inflammatory effect of 20 lactobacilli strains in BIE cells with the aim of finding the strain with the highest immunomodulatory capacity in the bovine system. First, we evaluated the effect of lactobacilli on BIE cells without any inflammatory challenge (Additional file 1: Figure S1A). BIE cells were treated with the different lactobacilli strains for 48 h and the levels of mRNA IL-6, IL-8 and MCP-1 were determined. Only the strain MEP221102 slightly increased levels of MCP-1, and MEP221108 and MEP221114 also slightly increased levels of IL-6 in BIE cells (Additional file 1: Figure S1A). On the contrary, several strains were able to significantly down-regulate the levels of IL-8 in BIE cells (Additional file 1: Figure S1A).

We found a significant 43% increase in the age-adjusted risk for VTE in untreated osteoporotic patients versus non-osteoporotic women. The profiles of our cohorts are consistent with the known major characteristics and risk factors for VTE [2, 29, 30]. It is well-known that the risk for VTE is QNZ nmr increased in the elderly [23, 30], which is a population exposed to an increasing number of risk factors (e.g., fractures, hospitalisations, and heart disease). Idasanutlin cost In our study, the incidence of VTE in the non-osteoporotic cohort was 2.4 per 1,000 PY for those aged 50 to 74 years, 5.2 per 1,000 PY between 75 and 80 years old, and 6.1 per 1,000 PY for those over 80 years.

A similar increase was observed in untreated osteoporotic patients from 4.3 to 8.3 per 1,000 PY in patients aged between 50

and 74 years and those over 80 years, respectively. These results are in the same range to those described elsewhere [29, 31, 32]. History of previous VTE is a major risk factor of recurrence of the condition [30]. In our study, the number of patients SAHA purchase with a previous medical history of VTE was higher in the untreated osteoporotic patients than in the non-osteoporotic patients. This could partly explain the observations of further recurrence of VTE in untreated osteoporotic patients. However, when the results were adjusted for medical history of VTE and additional risk factors, such as age, BMI, and use of oral corticosteroids for more than 3 months, the risk of VTE was still higher in untreated osteoporotic patients. These results

suggest that if these covariates participate in the risk of VTE, there is at least another risk factor most likely related to osteoporotic disease itself. Osteoporotic patients, generally, have a poor gait, an increased tendency to fall, and have related injuries such as fractures [33]. For example, the lifetime risk of hip fracture was estimated to be 17.5% in Caucasian women based on a life expectancy of 78.9 years [34]. Thus, osteoporosis and related health issues lead to decreased mobility, which is a known risk factor for VTE. Moreover, trauma and orthopaedic surgery Montelukast Sodium are among the strongest risk factors for VTE [35, 36]. Indeed, several reports have described that surgery is associated with a 6- to nearly 13-fold increased in the risk of VTE [23, 26, 29]. Orthopaedic surgery of the hip and knee has been reported to lead to thrombosis in 30% to 50% of patients without thromboprophylaxis [2]. Therefore, osteoporosis and its complications, fractures in particular, appear to be associated with an increased risk for VTE. Strontium ranelate is an anti-osteoporotic treatment for which meta-analysis of the pivotal phase III clinical studies indicated that the annual incidence of VTE was 0.9% over 5 years in the strontium ranelate group versus 0.6% in the placebo group, with a relative risk of 1.4 (95% CI, 1.0–2.0) [11].

43. Bordier C: Phase separation of integral membrane proteins in Triton-X114 solution. J Biol Chem 1981, 256:1604–1607.PubMed

44. Duffy MF, Noormohammadi AH, Baseggio N, Browning GF, Markham PF: Immunological and biochemical characterization of membrane proteins. In Methods in Molecular Biology. Edited by: Miles R, Nicholas R. Humana Press, Totowa, New Jersey; 1998:279–298. vol. 104 45. Ladefoged SA, Christiansen G: Mycoplasma hominis expresses two variants of a cell-surface protein, one a lipoprotein, and one not. Microbiology 1998,144(Pt 3):761–770.PubMedCrossRef 46. Inukai M, Takeuchi M, Shimizu K, Arai M: Mechanism of action of globomycin. J Antibiot (Tokyo) 1978,31(11):1203–1205.CrossRef 47. Inukai M, Ghrayeb J, Nakamura K, Inouye M: Apolipoprotein, an intermediate in JPH203 supplier the processing selleck products of the major lipoprotein of the Escherichia coli outer membrane. J Biol Chem 1984,259(2):757–760.PubMed 48. O’Brien-Simpson NM, Pathirana RD, Paolini RA, Chen YY, Veith PD, Tam V, Ally N, Pike RN, Reynolds EC: An immune response directed to proteinase and adhesin functional epitopes protects against Porphyromonas gingivalis-induced periodontal bone loss. J Immunol 2005,175(6):3980–3989.PubMed Competing interests The authors declare that they have no competing interests. Authors’ contributions I.S.P designed the study, performed the experiments and

data analysis, and drafted the manuscript, AK helped with the experiments, CC Salubrinal price contributed the ltuf siglac construct, P.D.V and M.D.G performed mass C-X-C chemokine receptor type 7 (CXCR-7) spectrometry identification and analysis and provided suggestions about the manuscript. G.F.B and P.F.M contributed to the study design, analysis, drafting and review of the manuscript. All authors have read and approved the manuscript.”
“Background Enterococci are normal constituents of the gastro-intestinal flora of humans and other animals [1–3]. Although they only occasionally cause infections in healthy individuals,

they are the third most commonly isolated gram positive organisms from hospital-associated (HA) infections in the United States and are increasingly reported in other countries [4, 5]. Enterococcal infections are often difficult to treat due to the number of antibiotics to which these organisms are resistant. Some antibiotic resistances are intrinsic, such as resistances to cephalosporins, while other antibiotic resistances are acquired through mutations or horizontal gene transfer, most notably the van systems that encode vancomycin resistance [6–12]. Several recent studies also confirmed that enterococci can transfer their resistance to even more virulent organisms, such as Staphylococcus aureus[13]. Enterococcus faecalis is the most common enterococcal species recovered from infections. However, in the last decade, infections with Enterococcus faecium have been on the rise in the United States, Europe, and South America [2–5, 14]. In the US, isolates of E. faecium now account for ca.

Under low-oxygen and aerated cultures, stationary phase induction of lrgAB expression was dramatically reduced when grown in 45 mM glucose, and similar levels of expression were observed in the wild-type and lytS mutant (Figure 1B), suggesting that growth in high levels of GW4869 manufacturer glucose abrogates oxygen-dependent regulation of lrgAB by LytST. Consistent with previously-published data [37], LytS did not appear to have a measurable effect on cidAB expression under any of the growth

conditions tested here (data not shown). In summary, LytST-dependent regulation of lrgAB expression is much more pronounced during low-oxygen growth and at low glucose levels. Figure 1 LytS-dependent expression of lrgAB in S . mutans AMN-107 cell line . Overnight cultures Gemcitabine chemical structure were diluted in THYE, containing either 11 mM (A) or 45 mM glucose (B) to an OD600 = 0.02 and grown at 37°C as static cultures at 5% CO2 (“low-O2”) or as aerobic shaking cultures at 250 RPM (“aerobic”). RNA was harvested at exponential (EP) and stationary phase (SP). Reverse-transcription, real-time PCR reactions, and determination of copy number were performed as described previously using lrgA and 16S-specific primers [37, 77]. Fold-change expression of lrgAB and 16S under each growth condition was calculated

by dividing the gene copy number of each test sample by the average gene BCKDHB copy number of UA159 EP. Data was then normalized by dividing each lrgAB fold-change value by its corresponding 16S fold-change expression value. Data represent the average of 3 biological replicates. Dark grey

bars represent UA159 and light grey bars represent lytS mutant. Error Bars represent the standard error (SEM). Microarray analysis of the LytS regulon Based on the transcriptional data presented above, the effects of LytST regulation on lrgAB expression are most evident while S. mutans is growing under conditions of low-oxygen (5% CO2) with a lower concentration of glucose. To begin to explore how LytST impacts critical phenotypes of S. mutans, RNA expression profiles in UA159 and the lytS mutant were compared using an RNA microarray approach. RNA was isolated from early exponential and late exponential growth phases from static planktonic cultures grown in BHI (containing 11 mM total glucose) at 37°C in a 5% CO2 atmosphere (Additional file 1: Table S1 and Additional file 2: Table S2). At early exponential growth phase, loss of LytS affected the expression of 40 genes (12 upregulated and 28 downregulated; P < 0.005; Additional file 1: Table S1). Most of the upregulated genes in early exponential phase displayed only a modest increase in expression and included genes involved in DNA repair, purine/pyrimidine metabolism, competence, and a number of unassigned and hypothetical ORFs.

cryaerophilus alleles were identified also at the glnA, gltA, pgm and tkt loci [see additional file 2 - Table S2], but not at the aspA locus that formed only one cluster. The existence of species-associated clustering at these six loci permits tentative identification of lateral transfer events. These events were not observed in A. butzleri because no alleles related phylogenetically to other species were identified, however, alleles related phylogenetically to those identified in A. butzleri were Lorlatinib molecular weight identified within A. cibarius

and A. skirrowii (i.e. tkt-90, tkt-91, aspA-73 and glnA-1). Similarly, A. skirrowii alleles were identified within A. cryaerophilus and A. thereius (e.g. aspA-125 and glnA-95), and an A. thereius allele was identified in A. cryaerophilus (glyA-306; see Figure 1B). Lateral transfer events identified by MLST have been reported

previously [27, selleck compound 32]. Figure 1 Dendrograms of Arcobacter atpA and glyA alleles. A: atpA; B: glyA. The dendrograms were constructed using the neighbor-joining algorithm and the Kimura two-parameter distance estimation method. The scale bars represent substitutions per site. The A. halophilus strain LA31B atpA and glyA selleck screening library sequences were extracted from the draft A. halophilus genome. Note the presence of a putative laterally-transferred allele within the A. thereius glyA cluster. Clustering of the glyA alleles (including alleles at both glyA genes) is noticeably different from clustering at the other six loci (Figure 1B). Here, as at the other six loci, the A. butzleri and A. thereius glyA alleles form separate clusters distinct from the alleles of the other characterized arcobacters.

However, the glyA alleles of A. cryaerophilus and A. skirrowii are indistinguishable phylogenetically, with the A. cibarius glyA alleles forming a deep branch within the A. cryaerophilus/A. skirrowii cluster. Additionally, the A. cryaerophilus/A. skirrowii glyA cluster is highly divergent, relative to the A. cryaerophilus and A. skirrowii clusters at the other MLST loci. Phylogenetic analysis of the Arcobacter STs, following CLUSTAL alignment of the concatenated ADAMTS5 allele sequences for each unique profile, indicated that these STs clustered also by species (Figure 2). Arcobacter thereius profiles formed a clade distinct from A. skirrowii and the other Arcobacter species, providing additional evidence that the strains within this clade are exemplars of a novel Arcobacter species. Two groups of A. cryaerophilus profiles were observed: ‘group 1′ and ‘group 2′ profiles were composed primarily of ‘group 1′ and ‘group 2′ MLST alleles, respectively. Based on SDS-PAGE analysis of whole-cell protein extracts and 16S restriction fragment length polymorphism analysis, two subgroups within A. cryaerophilus were identified by Kiehlbauch et al. and Vandamme et al. [33, 34]. These A.

PubMedCrossRef 19. Wolfson JS, Hooper DC, Mchugh GL, Bozza MA, Swartz MN:

Mutants of escherichia-coli K-12 exhibiting reduced killing by both quinolone and beta-lactam antimicrobial agents. Antimicrob Agents Ch 1990,34(10): 1938–1943.CrossRef 20. Joers A, Kaldalu N, Tenson T: The frequency of persisters in escherichia coli reflects the kinetics of awakening from dormancy. J Bacteriol 2010,192(13): 3379–3384.PubMedCrossRef 21. Luidalepp H, NCT-501 solubility dmso Joers A, Kaldalu N, Tenson T: Age of inoculum strongly influences persister frequency and Can mask effects of mutations implicated in altered persistence. J Bacteriol 2011,193(14): 3598–3605.PubMedCrossRef 22. Foti JJ, Devadoss B, Winkler JA, Collins JJ, Walker GC: Oxidation of the guanine nucleotide pool underlies cell death by bactericidal antibiotics. Science 2012,336(6079): 315–319.PubMedCrossRef 23. Wiuff C, Andersson DI: Antibiotic treatment in TSA HDAC vitro of phenotypically tolerant bacterial populations. J Antimicrob Chemoth 2007,59(2): 254–263.CrossRef 24. Spoering AL, Vulic M, Lewis K: GlpD and PlsB participate in persister cell formation in Eschetichia coli. J Bacteriol 2006,188(14): 5136–5144.PubMedCrossRef 25. Hansen S, Lewis K, Vulic M: Role of global regulators and nucleotide metabolism in antibiotic tolerance in Escherichia coli. Antimicrob Agents Ch 2008,52(8): 2718–2726.CrossRef

26. Ishii S, Ksoll WB, Hicks RE, Sadowsky MJ: Presence and growth of naturalized Escherichia coli in temperate soils from lake superior watersheds. Appl Environ Microb 2006,72(1): 612–621.CrossRef 27. Luo CW, Walk ST, Gordon DM, Feldgarden M, Tiedje JM, Konstantinidis KT: Genome sequencing of environmental Escherichia coli expands understanding of the ecology and speciation of the model bacterial species. P Natl Acad Sci USA 2011,108(17): 7200–7205.CrossRef 28. Oliphant CM, Green GM: Quinolones: a comprehensive review. Am Fam Physician 2002,65(3): 455–464.PubMed 29. Correia FF, D’Onofrio A, Rejtar T, Li LY, Karger BL, Makarova K, Koonin EV, Lewis K: Kinase activity of overexpressed HipA is required for growth arrest and multidrug

tolerance in Escherichia coli. Rucaparib in vitro J Bacteriol 2006,188(24): 8360–8367.PubMedCrossRef 30. Vazquez-Laslop N, Lee H, Neyfakh AA: Increased persistence in Escherichia coli caused by controlled expression of BVD-523 order toxins or other unrelated proteins. J Bacteriol 2006,188(10): 3494–3497.PubMedCrossRef 31. Hooper DC, Wolfson JS: Mode of action of the New quinolones – New data. Eur J Clin Microbiol 1991,10(4): 223–231.CrossRef 32. Jacoby GA: Mechanisms of resistance to quinolones. Clin Infect Dis 2005, 41:S120-S126.PubMedCrossRef 33. Silander OK, Ackermann M: The constancy of gene conservation across divergent bacterial orders. BMC Research Notes 2009, 2:2.PubMedCrossRef 34. Johnson PJT, Levin BR: Pharmacodynamics, population dynamics and the evolution of persistence in staphylococcus aureus. PLoS Genet 2013. in press 35.

4 to 40.1% of IGS-T-RFs present in nodules were detected in the respective soil sample. Figure 4 shows the similarity relationships between IGS-T-RFLP profiles. Non-metric MDS plot of IGS-T-RFLP profiles (Figure 4a) showed a possible separation of nodule and soil populations AZD2014 on the second dimension. In particular, the nodule population in pot 1 was more separated from the soil population of the same pot and from the populations of the other pots. On the contrary, nodule populations of pots 2 and 3 were the closest ones,

with soil population of pot 3 in the same cluster (Figure 4b), suggesting a possible effect of plant genotype as previously shown [23, 36]. However, in agreement with the ARRY-438162 solubility dmso high number of single-sample haplotypes detected, an AMOVA carried out to evaluate the variance contribution to a hypothetical differentiation

of soil and nodule S. meliloti population showed that 17.37% only of variance was attributed to a soil-nodule separation, the remaining 82.63% of variance being due to among-nodules and among-soil differences. Additionally, no statistical significant separation (P < 0.46) was detected for groupings based on the two plant genotypes present in the mesocosms. Figure 4 a) Non-metric MDS plot of similarities of IGS-T-RFLP profiles from S. meliloti population analysis. a) The pattern of similarity of S. meliloti populations has been inspected by using Non-metric Multidimensional scaling (N-MDS) based on Jaccard similarity matrix. Stress O-methylated flavonoid = 0.0898. b) Cluster analysis based on Jaccard similarity matrix. Scale bar represents Jaccard similarity coefficient Discussion In recent years

there has been an increasing interest in exploring the bacterial flora associated with plants [37–41]. A recent field survey indicates [8] that plant aerial parts (leaves) harbor complex, but highly PDGFR inhibitor variable, bacterial communities, and that only a small number of bacterial taxa (mainly belonging to Alphaproteobacteria) are plant-specific. In the experiments reported here, as in the majority of the reports on endophytic microflora, we refer to endophytic and epiphytic bacteria indicating all those that are inside the plant tissue or strongly adhering to the plant surface, such as they resist washing and sterilization (or their DNA is retained by plant tissue), therefore a more correct definition could be “plant-associated bacteria”. The present study shows that root nodules and aerial parts of Medicago sativa plants grown in mesocosm conditions, harbor distinct bacterial communities with specific signatures at the class, family and species levels and that these communities do not mirror soil bacterial communities.