gingivalis invasion (Figures 6 and 8). Adhesion of P. gingivalis to host cells is multimodal and involves the interaction of bacterial cell surface adhesins with receptors expressed on the surfaces of epithelial cells. Adhesion of P. gingivalis to host cells is mediated by many extracellular components, including fimbriae, proteases, hemagglutinins,

and lipopolysaccharides (LPS). Among the large array of virulence factors produced by P. gingivalis, the major fimbriae (FimA), as well as cysteine proteinases (gingipains), contribute to the attachment to and invasion of oral epithelial cells [49,50]. On the other hand, integrins can act as receptors for the integrin-binding proteins of P5091 datasheet several bacterial species [51–53]. P. gingivalis also associates with β1 and α5β1 integrin heterodimers via FimA. αVβ3 integrin also mediates fimbriae adhesion to epithelial cells [48]. In addition, carbohydrate chains on epithelial cell membrane selleck products glycolipids have been reported to act as receptors for P. gingivalis [54]. It has been demonstrated that ICAM-1 is required for the invasion of P. gingivalis into human oral epithelial cells [36]. Various cytokines including TNF-α induce expression of ICAM-1 [55,56]. Therefore,

ICAM-1 expresion and this website P. gingivalis invasion in periodontal sites may be associated with the primary stages of the development and progression of chronic periodontitis. It has been demonstrated that a large number of intracellular bacteria are present in IL-6-treated cells that

have an increasing amount of Rab5 [41]. These results indicate Selleck Hydroxychloroquine that overexpression of Rab5 by cytokines may promote the fusion of bacteria containing phagosomes with early endosomes and thereby inhibit their transport to lysosomes and may help in prolongation of bacterial survival in host cells and thus establish a chronic infection that could exacerbate the immune response. At periodontal sites, such phenomena could occur. Periodontopathic bacteria induce various cytokines including TNF-α. It has been shown that of TNF-α is upregulated in periodontitis, e.g., in gingival crevicular fluid [23] and in gingival tissues [24]. Therefore, periodontopathic bacteria including P. gingivalis induce the production of cytokines including TNF-α in periodontal tissues. Excess TNF-α in periodontal tissues activates gingival epithelial cells and increases the possibility of P. gingivalis invasion in the cells, resulting in persistence of P. ginigvalis infection and prolongation of immune responses in periodontal tissues. Conclusions We demonstrated that P. ginigvalis invasion into human gingival epithelial cells was enhanced by stimulation with TNF-α. TNF-α in periodontal tissues, the production of which is induced by plaque bacteria including P. gingivlis and is increased by diabetes, may lead to persistent infection of P. ginigvalis and prolongation of immune responses in periodontal tissues. Methods Bacterial strains and growth conditions P.

melanogaster w1118 . This increase is possibly caused by the specific effect of the Wolbachia strain wMelPop, since it was not observed in wMel-infected D. melanogaster Canton S. Our current electron microscopic observations allowed us to identify

changes in Wolbachia morphology in apoptotic germline cells. Morphological evidence of apoptosis in germarium cells The ultrastructural features of apoptosis in the cyst cells of higher eukaryotes have gained wide recognition. They include cytoplasmic and nuclear condensation (pyknosis); nuclear fragmentation (karyorrhexis); normal morphological appearance of cytoplasmic organelles; 4EGI-1 chemical structure an intact plasma membrane [3, 4]. The ultrastructural SRT2104 purchase changes we identified here in D. melanogaster cyst cells are consistent with the above hallmarks. Furthermore, we revealed mitochondria of two types: intact morphology in one type and markedly swollen with a few cristae in the other. A similar heterogeneity of mitochondrial ultrastructure has been observed during apoptosis in granulose cells of Japanese quail (Coturnix coturnix japonica) [30], lymphocytes from leukemia patients [31],

and megakaryocytes from patients with idiopathic thrombocytopenic purpura [32]. It has been suggested that the swollen mitochondria release cytochrome c, which activates a cascade of proteolytic Selleck AZD8931 reactions, while the normal ones retain their capacity for ATP synthesis, a process apoptosis requires [30, 31, 33]. According to our qualitative analysis using EM, morphological evidence of apoptosis was revealed in germline cells from uninfected flies and those infected with wMel and wMelPop. Thus, there are reasons for inferring that the endosymbiont Wolbachia in D. melanogaster cystocytes has no effect on sequential passage of intracellular organelles through apoptosis. To reveal the possible differences

between the effect of the wMel and wMelPop strains on apoptosis in the germaria, additional PI-1840 morphometric analysis of the number of apoptotic structures and of Wolbachia density in the cystocytes is required. Structural features of Wolbachia in apoptotic cysts Wolbachia with matrix of moderate and low electron density in apoptotic cells in region 2a/2b of the germarium have been previously encountered in other types of D. melanogaster ovaries [34] and they presumably reflect different functional states of bacteria. Wolbachia with disrupted envelopes and light matrix are possibly dying bacteria in apoptotic cells. Such appearance has not been observed in Wolbachia injured or killed by heat stress [35] and tetracycline [36]. The electron-dense bacteria-like structures at the periphery of region 1 of the germarium may be evidence of changes in dying Wolbachia.

Additional inflammation caused by surgery is seen as additional trauma and has been considered as a possible risk factor for organ failure such as ARDS [18]. Much to our surprise the increased damage caused by IMN only partly induced changes in the systemic inflammatory response (only monocyte

HLA-DR expression in patients with isolated femur Vistusertib supplier fractures). Most striking was the absence of additional PMN activation after intramedullary nailing. This lack of change in PMN phenotype during IMN is in line with suggestions from a previously published report [19]. In that cohort, no increase was seen in MAC-1 expression on PMNs after bilateral femur fracture fixation. Thus, the extend of PMN activation appears mainly determined by the severity of initial trauma and is apparently not altered by intramedullary nailing. In contrast, plasma IL-6 levels and monocyte HLA-DR were significantly altered by intramedullary nailing. Thus, an impact of the surgical procedure can be measured by cytokines and the monocyte compartment. The blood samples were taken 1 hour prior to IMN and 18 hours after IMN, regardless of the interval between trauma and surgery. Although this affects the reproducibility of the results, it reflects daily care practice. 18 hours after IMN the peak of plasma IL-6 levels will be passed (max

at 6 hours post-operatively), but the changes in PMN phenotype will be NVP-BSK805 most defined. PMN phenotype behaved similarly in all patients, therefore, 38 patients were sufficient to state the conclusion. Because we analyzed the functional phenotype of PMNs and monocytes, more information was obtained than merely static phenotypes. The inflammatory cellular response deficit to the development of ARDS appears to be mainly determined by the initial injuries

and not the additional insult by IMN. Acknowledgements This project was funded by the AO Foundation, grant S-06-14H. References 1. Rubenfeld GD, Caldwell E, Peabody E, Weaver J, Martin DP, Neff M, et al.: Incidence and outcomes of acute lung injury. N engl j med 2005, 20;353:1685–1693.CrossRef 2. Pape HC, Auf’m'kolk M, Paffrath T, Regel G, Sturm JA, Tscherne H: Primary intramedullary femur fixation Isoconazole in multiple trauma patients with associated lung contusion–a cause of posttraumatic ards? J trauma 1993, 34:540–547.PubMedCrossRef 3. Bosse MJ, Mackenzie EJ, Riemer BL, Brumback RJ, Mccarthy ML, Burgess AR, et al.: Adult respiratory distress syndrome, pneumonia, and mortality following thoracic injury and a femoral fracture treated either with intramedullary nailing with reaming or with a plate. A comparative study. J bone joint surg am 1997, 79:799–809.PubMed 4. Dunham CM, Bosse MJ, Clancy TV, Cole FJ, Coles MJ, Knuth T, et al.: Practice management guidelines for the optimal timing of CP-690550 concentration long-bone fracture stabilization in polytrauma patients: the east practice management guidelines work group. J trauma 2001, 50:958–967.PubMedCrossRef 5.

PubMedCentralPubMedCrossRef 16. Cotter SE, Surana NK, 3rd St Geme JW: Trimeric autotransporters: a distinct subfamily of autotransporter VX-689 manufacturer proteins. Trends Microbiol

2005,13(5):199–205.PubMedCrossRef 17. Henderson IR, Navarro-Garcia F, Nataro JP: The great escape: structure and function of the autotransporter proteins. Trends Microbiol 1998,6(9):370–378.PubMedCrossRef 18. Stathopoulos C, Hendrixson DR, Thanassi DG, Hultgren SJ, 3rd St Geme JW, 3rd Curtiss R: Secretion of virulence determinants by the general secretory pathway in gram-negative pathogens: an evolving story. Microbes Infect 2000,2(9):1061–1072.PubMedCrossRef 19. Henderson IR, Navarro-Garcia F, Desvaux M, Fernandez RC, Ala’Aldeen D: Type V protein secretion pathway: the autotransporter story. Microbiol Mol Biol Rev 2004,68(4):692–744.PubMedCentralPubMedCrossRef 20. Linke D, Riess T, Autenrieth IB, Lupas A, Kempf VA: Trimeric autotransporter adhesins: variable structure, common function. Trends Microbiol 2006,14(6):264–270.PubMedCrossRef 21. Hoiczyk E, Roggenkamp A, Reichenbecher M, Lupas A, AMN-107 supplier Heesemann J: Structure and AZD1152 manufacturer sequence analysis of Yersinia YadA and Moraxella UspAs reveal a novel class of adhesins. Embo J 2000,19(22):5989–5999.PubMedCentralPubMedCrossRef 22. Ciabattini A, Giomarelli B, Parigi R, Chiavolini D, Pettini E, Arico B, Giuliani

MM, Santini L, Medaglini D, Pozzi G: Intranasal immunization of mice with recombinant Streptococcus gordonii expressing NadA of Neisseria meningitidis induces systemic bactericidal antibodies and local IgA. Vaccine 2008,26(33):4244–4250.PubMedCrossRef 23. Bowe F, Lavelle EC, McNeela EA, Hale C, Clare S, Arico B, Giuliani MM, Rae A, Huett A, Rappuoli R, Dougan G, Mills KH: Mucosal vaccination against serogroup B meningococci: induction of bactericidal antibodies and cellular immunity following intranasal immunization with NadA of Neisseria meningitidis and mutants

of Escherichia coli heat-labile enterotoxin. Infect Immun 2004,72(7):4052–4060.PubMedCentralPubMedCrossRef 24. Liu DF, Mason KW, Mastri M, Pazirandeh M, Cutter D, Fink DL, 3rd St Geme JW, Zhu D, Green BA: The C-terminal fragment of the internal 110-kilodalton passenger domain of the Hap protein of nontypeable Haemophilus Farnesyltransferase influenzae is a potential vaccine candidate. Infect Immun 2004,72(12):6961–6968.PubMedCentralPubMedCrossRef 25. Cutter D, Mason KW, Howell AP, Fink DL, Green BA, 3rd St Geme JW: Immunization with Haemophilus influenzae Hap adhesin protects against nasopharyngeal colonization in experimental mice. J Infect Dis 2002,186(8):1115–1121.PubMedCrossRef 26. Alamuri P, Eaton KA, Himpsl SD, Smith SN, Mobley HL: Vaccination with proteus toxic agglutinin, a hemolysin-independent cytotoxin in vivo, protects against Proteus mirabilis urinary tract infection. Infect Immun 2009,77(2):632–641.PubMedCentralPubMedCrossRef 27. Waag DM, Deshazer D: Glanders: New Insights into an old Disease. In Biological Weapons Defense: Infectious Diseases and Counterbioterrorism.

9 0.8     0.9     Female (%) 22 (51%) 8 (53%)               Location tumor Proximal (%) 21 (49%) 10 (67%) 0.2 0.6     0.7     Distal (%) 22 (51%) 5 (33%)               Median age at diagnosis (years) <69.7 21 (49%) 8 (53%) 0.8 0.008 2.5 0.01 0.006 2.8 0.008 >69.7 22 (51%) 7 (47%)     (1.2–4.9)     (1.3–5.8)   TNM stage

I and II 28 (65%) 11 (73%) 0.6 0.002 2.9 0.003 0.002 3.3 0.002 III 15 (35%) 4 (27%)     (1.4–5.8)     (1.5–6.8)   Pathway MSI 7 (16%) 5 (33%) 0.2 0.7     0.6     MSS 36 (84%) 10 (67%)               CXCR4 Strong       0.07 2.6 0.04 0.03 #VS-4718 supplier randurls[1|1|,|CHEM1|]# 3.7 0.02 Weak         (1.0–6.2)     (1.35–11)   Clinicopathological characteristics and survival results of patients with high and low nuclear protein expression of CXCR4. Level of CXCR4 was determined in an independent panel colorectal cancer patients.

The table displays buy GDC-0994 the results after immunohistochemical staining and semi-quantitative analyses of nuclear expression of CXCR4 in tumor cells, as described in materials and methods. For nuclear CXCR4 staining, 15 tumors were classified as low (26%) and 43 were strong (74%). On the left side of the table the distribution of high versus low expression of CXCR4 with respect to clinical and pathological characteristics and the relation of CXCR4 to clinicopathological factors are displayed. On the right side of the table, prognostic factors are displayed. Univariate Cox regression analyses were performed to identify prognostic factors for disease free and overall survival.

All factors with a p value ≤ 0.10 were subjected to Multivariate Cox regression analysis. Numbers (N) of patients are indicated with percentages shown in parentheses MSS microsatellite stable; MSI microsatellite instable; HR Hazard Ratio; CI Confidence Interval 17-DMAG (Alvespimycin) HCl aStatistical significant p-values are in bold Discussion The expression of CXCR4 has been detected in a large number of different types of cancers, together with its use as prognostic biomarker [3, 27]. In the present study we evaluated the expression of CXCR4 in colorectal cancer by quantitative RT-PCR and immunohistochemical staining. Strong expression of nuclear localized CXCR4 and high RNA levels of CXCR4 were both independent significant predictors for poor overall and disease free survival. Our results were consistent with others’ recent RT-PCR data [10, 15]. We found no correlation between expression of CXCR4 mRNA (RT-PCR) and nuclear CXCR4 expression (immunohistochemistry).

First there is localised destruction (effacement) of the microvilli, which leads to intimate attachment of the bacterium to the host cell [20]. EPEC and EHEC encode a specific intimin receptor, translocated intimin receptor (Tir). This receptor is translocated directly into the host cells via a type III secretion system, where it becomes expressed on the cell surface [21, 22]. Intimin binds to Tir leading to its activation, which results in actin polymerisation within the host cell and the formation of a pedestal, facilitating

tighter adherence between the host cell and the bacterium [17, 23]. Other eukaryotic receptors have been suggested for intimin, including nucleolin and some β1 integrins, but as yet it is unknown if these interactions have a role in vivo [24, 25]. There is considerable sequence variation between the intimins from different E. coli strains and they have been categorised into different subtypes, each with a high affinity for its own cognate selleck Tir [26]. However, despite this diversity, it has been found that within the C-terminal binding domain there are four tryptophan residues and two cysteine residues, which are conserved between all subtypes [27, 28]. The two cysteines are also conserved in similar locations within the Y. TPCA-1 pseudotuberculosis invasin. In both invasin and intimin a disulphide bond is formed, which is essential for the structure of the C-terminal binding

domain and therefore required for full functionality [29, 30]. In the instance of invasin, disruption of either cysteine results in an inability to bind to integrin, BTK inhibitor and therefore is defective for invasion [29]. Analysis of Y. pseudotuberculosis

strain IP32953 sequence data identified a gene encoding a protein with significant amino acid similarity to invasin and intimin, which has not been previously investigated. We have termed this protein Ifp (intimin family protein) and intriguingly it has been mutated to a pseudogene in all seven Y. Tau-protein kinase pestis genomes sequenced to date. Examination of the amino acid sequence of Ifp revealed that three of the four tryptophans and both of the cysteine residues that are important in intimin function are conserved. However, no Tir orthologue can be identified in the IP32953 genome sequence. Given the amino acid similarity of Ifp to both invasin and intimin, coupled with it being putatively non-functional in Y. pestis, we postulated that Ifp may be an adhesin. We demonstrate that Ifp is a functional adhesin that binds to distinct foci on host cells. Expression occurs in late log or early stationary phase at 37°C only and coincides with a decline in the expression of invasin at this temperature. Methods Strains used and culture conditions All Y. pseudotuberculosis strains were cultured in Luria-Bertani (LB) broth Miller (BD Biosciences, Oxford, UK) or on LB agar (Novagen, Nottingham, UK) at 28°C unless otherwise stated. The retention of the virulence plasmid (pYV) was screened by plating Y.

34×10−8 6.14×10−11 ± 3.95×10−12 0.83 ± 0.01 1.4 vol.% 2.05×10−6 ± 7.90×10−8 1.44×10−9

± 8.19×10−11 0.71 ± 0.01 Figure 5 presents the J-E characteristic of the PVDF composite with 1.4 vol.% SRG sheets. The composite exhibits a much stronger nonlinear conduction behavior compared with the polymer composites with carbon nanotubes/nanofibers [50]. Similarly, other SRG/PVDF composites with SRG content above p c also exhibit such a behavior. As with other carbon/polymer composites, the current density J can be divided into linear J L and nonlinear J NL . The nonlinear part is caused by the Zener tunneling of electrons between the SRG sheets. As shown in the inset of Figure 5, the Zener tunneling predicts the nonlinear current density AP26113 datasheet (J NL) very well on the basis of the tunneling equation, i.e., J = AE n exp(−B/E) where A, B, and n are constants [51]. To the best of our knowledge, this is the first report about Zener effect in graphene/polymer BMN 673 purchase composite. From our previous study, a homogeneous dispersion

of conductive filler within the insulating matrix tends to cause strong Zener current [52]. Hence, the strong electrical nonlinearity provides further support for the uniform dispersion of the SRG sheets in the PVDF matrix. Figure 5 J – E characteristic of SRG/PVDF composite with p = 1.4 vol.%. The inset shows the agreement of nonlinear current density (J NL) with Zener tunneling density J = AE n 4-Aminobutyrate aminotransferase exp(−B/E). Conclusions SRG/PVDF composite was prepared by in-situ solvothermal reduction of graphene oxide in the PVDF solution. The large aspect ratio of SRG sheets in combination with uniform dispersion in the polymer matrix led to a relatively low percolation threshold of 0.31 vol.%, which is smaller than

graphene/polymer composites prepared by direct blending chemically/thermally reduced GO sheets with PVDF. It is found that only 0.5 vol.% SRG doping will increase the dielectric constant of the material from 7 to about 105, while keeping the conductivity at a low level. Such a dielectric performance is superior to those of carbon nanotube/nanofiber based polymeric composites. The AC conductivity of the composite above p c follows the universal dynamic response, as with many other conductor-insulator systems. Moreover, the electrical nonlinearity of these composites is stronger than the carbon nanotube/nanofiber filled polymer system, resulting from the Zener tunneling effect between the uniformly dispersed SRG sheets. Acknowledgment This work is supported by the project (R-IND4401), Shenzhen Research Institute, City Unversity of Hong Kong. References 1. Psarras GC: Hopping conductivity in polymer matrix–metal URMC-099 particles composites. Composites Part A 2006, 37:1545–1553.CrossRef 2. Mrozek RA, Cole PJ, Mondy LA, Rao RR, Bieg LF, Lenhar JL: Highly conductive, melt processable polymer composites based on nickel and low melting eutectic metal. Polymer 2010, 51:2954–2958.CrossRef 3.

Freeze-dried doxorubicin-loaded micelles were dissolved in 4 mL of a DMSO and methanol mixture (1:1), and the absorbance was check details measured at 480 nm using a UV-1601 spectrophotometer (Shimadzu Corp., Kyoto, Japan). The drug loading content (DLC) is defined as the ratio of mass of the drug encapsulated within the micelles to the total mass of drug-loaded micelles, while the entrapment efficiency (EE) is the ratio see more of mass of drug loaded into the micelles to the mass of drug initially added. The DLC and EE were calculated according to the following equations: (1) (2) In vitro drug release study The drug

release experiment was carried out in vitro. A doxorubicin-loaded micelle solution previously prepared by dialysis was used for release analysis. This solution was introduced into the dialysis membrane. Subsequently, the dialysis membrane was placed in a 200-mL beaker with 100 mL of phosphate-buffered saline (PBS). This

beaker was placed on a magnetic stirrer with a stirring speed of 100 rpm at 37°C. At suitable intervals, 3 mL samples were taken from the release medium and an equivalent volume of fresh medium was added. The concentration of doxorubicin in each sample was measured by ultraviolet–visible spectrophotometry at 480 nm. Cytotoxicity analysis Human colorectal adenocarcinoma (DLD-1) GS-1101 nmr and Chinese hamster lung fibroblast (V79) cell lines were obtained from the American Type Culture Collection (Manassas, VA, USA). DLD-1

cells were cultured and maintained in Roswell Park Memorial Institute-1640 (RPMI-1640) medium, whereas V79 cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM). Both cell lines were supplemented with 10% FBS and 1% penicillin-streptomycin and maintained at 37°C in a humidified 5% CO2/95% air atmosphere. Megestrol Acetate The impact of the blank micelles on cell viability was assessed using V79 cells. Cultured cells maintained in DMEM were seeded in 96-well culture plates at 4 × 104 cells per well and incubated for 24 h. The cells were then treated with increasing concentrations of blank micelles ranging from 31.25 to 500 μg · mL−1 and incubated for an additional 24 h at 37°C in a 5% CO2/95% air atmosphere. Next, 20 μL of Alamar Blue® (Invitrogen, Carlsbad, CA, USA) was introduced to every well, and the cells were incubated for a further 4 h. The absorbance of each sample was measured at 570 nm with a microplate reader (Varioskan Flash, Thermo Scientific, Waltham, MA, USA). Cell viability was determined using the following equation: (3) The cytotoxicity of the doxorubicin-loaded micelles was determined using the Alamar blue assay. DLD-1 cells were seeded in 96-well culture plates at 2 × 104 cells per well and incubated for 48 h at 37°C in 5% CO2/95% air atmosphere. After the medium was removed, the cells were treated with 200 μL of 50, 25, 12.5, 6.25, 1.56, 0.19, and 0.09 μg · mL−1 of free doxorubicin and doxorubicin-loaded micelles, respectively.

of genes GO:0006996 organelle organization 20 GO:0007049 cell cycle 14 GO:0051276 chromosome organization 10 GO:0006334 nucleosome assembly 9 GO:0031497 chromatin assembly and disassembly 9 GO:0034728 nucleosome organization 9 GO:0065004 protein-DNA complex assembly 9 GO:0006323 DNA packaging 9 GO:0034622 cellular macromolecular learn more complex assembly 9 Table 3 List of biologic process for the up-expressed genes in Belnacasan SL1344 infection group relative to that of SB1117 infection group at 4 day s GO ID Term No. of genes GO:0065007 biological regulation 70 GO:0050794 regulation of cellular

process 66 GO:0032501 multicellular organismal process 47 GO:0007165 signal transduction 45 GO:0007154 cell communication 45 GO:0007166 cell surface receptor linked signal transduction 38 GO:0042221

response to chemical stimulus 14 GO:0006915 apoptosis 10 GO:0008219 cell death 10 Table 4 List of biologic process for the down-expressed genes in SL1344 infection group relative to that of SB1117 infection group at 4 days GO ID Term No. of genes GO:0003008 system process 39 GO:0050877 neurological system process 37 GO:0007186 G-protein coupled receptor protein signaling pathway 35 GO:0007608 sensory perception of smell 27 GO:0007606 sensory perception of chemical stimulus 27 GO:0007268 synaptic transmission Luminespib 7 In 347 up-regulated genes in the SL1344 infection group relative to SB1117 infection group at 8 hours (Table 1), 230 transcripts were assigned specific GO terms. GOEAST analysis showed that most of these genes participated in cell communication (71 genes) and signal transduction (64 genes). Shown in Table 2, 227 genes were down-regulated in the SL1344 infected group relative to SB1117 infection group at 8 hours. We found that 174 transcripts were assigned specific GO terms. Of these transcripts, Carteolol HCl 76.6% were annotated as being involved in biological

processes, and a significant number of transcripts were assigned known functions in organelle organization (20 genes), cell cycle (14 genes), chromosome organization (10 genes), chromatin assembly and disassembly (9 genes), nucleosome organization (9 genes), protein-DNA complex assembly (9 genes), DNA packaging (9 genes), and cellular macromolecular complex assembly (9 genes). Annotation showed that many of the genes belong to the centromere protein and the histone family protein. This result indicates that most of biological processes down-regulated by AvrA relate to nuclear function. In order to confirm the analysis results, we compared the cellular component of ontology for the two groups using the Multi-GOEAST analysis tool. As shown in Figure 4 all of the down-regulated GO terms are associated with the nucleus (green box), whereas up-regulated processes were associated with membrane and cytoplasm (red box).

However, based on the normalized signal intensity, only vanilate demethylase genes showed a significant increase (p < 0.05) under eCO2 (Additional file 10). The details about this gene are described in Additional file 5. The above results clearly indicate that microbial CO2 fixation may increase, and that microbial degradation and utilization of labile C substrates (e.g., starch, cellulose) may also increase at eCO2, but the degradation of recalcitrant C (e.g., lignin) may not be stimulated by eCO2. Responses

of N cycling genes to eCO2 Sixteen enzymes/genes involved in different N cycling processes were selected in GeoChip 3.0 to target important N cycling processes, such as N2 fixation, nitrification, and denitrification. #click here randurls[1|1|,|CHEM1|]# Based on the total signal intensity detected, significant changes were observed in nifH and nirS, but not other N cycling genes. N2 fixation is exclusively performed by prokaryotes, and nifH encoding the iron protein of Milciclib in vitro N synthase complex, nitrogenase, is the most widely used functional gene marker for N2 fixation [29] and also a phylogenetic marker for nifH-containing organisms [30]. A total of 147 nifH gene variants were detected with 92 shared by both aCO2 and eCO2 samples, 41 unique to eCO2, and 15 unique to aCO2 samples. The total normalized signal intensity of these detected nifH genes was significantly (p < 0.05) higher at

eCO2 than that at aCO2. Ten gene variants were significantly (p < 0.05) increased, and five were significantly decreased at eCO2. More than 69% of the nifH genes detected were affiliated with uncultured or unidentified microorganisms, and five (44829093, 12001884, 780709, 89512880, and 3157614) had >3.0% of the total nifH gene signal intensity. For 13 significantly increased nifH gene variants, ten were from the uncultured or unidentified bacteria, Farnesyltransferase and three (116697525, 2897667, and 148568718) were derived

from Syntrophobacter fumaroxidans MPOB, Paenibacillus macerans, and Roseiflexus sp. RS-1, respectively. Similarly, for five significantly decreased genes detected, three were from unidentified marine eubacterium and unidentified bacteria, and two (77463858 and 138897063) were derived from Rhodobacter sphaeroides 2.4.1 and Geobacillus thermodenitrificans NG80-2, respectively (Figure 4). It is also noted that nine of the top ten abundant genes were from uncultured or unidentified bacteria (Figure 4). Figure 4 The top ten abundant and other significantly changed nifH genes. The number of the probes detected from eCO2 and aCO2 were presented following the bars in parentheses. The statistical significant results of response ratio were shown in front of the GenBank accession number of the probes (**p < 0.05, *p < 0.10). NifH has been classified into five distinct evolutionary groups [31].