Another possibility is that PilT may rather play a role in the environment and/or in transmission of tularemia than in the animal/human infection. Combretastatin A4 in vitro With the genetic tools and the availability of specific mutants in the Tfp encoding gene clusters of SCHU S4, it will now be possible to address the role of the Tfp system in other infection models, for survival in the environment, and perchance for vector-borne transmission. Conclusions We have shown that pilA is required for full virulence of SCHU S4 in mice – a result in line with our earlier findings in type B strains. In addition, we have also demonstrated that the pilin assembly genes,

pilC and pilQ, are needed for full virulence of SCHU S4. An unexpectedly finding is that PilT, even though it is functional only in type A strains, did not contribute to virulence in the mouse subcutaneous infection model. Methods Bacterial strains, plasmids, growth conditions, and DNA methods The bacterial strains and plasmids used in this study are listed in Table 2. F. tularensis

strains were grown on modified Thayer-Martin agar or Blood Cystine Glucose agar (BCGA) at 37ºC in 5% ARN-509 concentration CO2. Escherichia coli strains were grown on blood agar base (BAB; Merck) plates or in Luria Bertani broth (LB). Antibiotics were used at the following concentrations: kanamycin 50 μg/ml and chloramphenicol 2.5 μg/ml (F. tularensis), or 25 μg/ml (E. coli). Preparation of plasmid DNA, Foretinib chemical structure restriction enzyme digests, ligations and transformations into E. coli were performed essentially as described [28]. Generally, the primers (Table 3) were constructed based on the genomic information from the FSC237 (SCHU S4) and FSC155 (LVS) genomes. The amplified PCR fragments were first cloned into the pCR®4.0-TOPO cloning vector (Invitrogen AB, Stockholm, Sweden), sequenced by Eurofins MWG Operon, and subsequently cloned into the suicide vectors pSMP22 [29] or pDM4 [30]. Table

2 Strains and plasmids used in this study Strains Genotype/phenotype Source F. tularensis     FSC237 tularensis; SCHU S4 Human ulcer 1941, Ohio   FSC237; ΔpilA; deletion of codons 1-135 This study   FSC237; ΔpilC (FTT1134); in frame deletion of codons 5-405 This study   FSC237; ΔpilQ (FTT1156); in frame deletion of codons 13-593 This study   FSC237; ΔpilT (FTT0088); in frame deletion of codons 7-336 This study E. Amobarbital coli     Top10 F- mcrA Δ(mrr-hsdRMS-mcrBC), Φ80lacZΔM15 ΔlacX74 recA1 deoR araD139 (Δara-leu)7697 galU galK rpsL (Smr) endA1 nupG Invitrogen S17-1Λpir recA, thi, pro, hsdR – M+,7> TpR, SmR [32] Plasmids     pCR®4.0 TOPO-cloning vector. AmpR, KmR Invitrogen pDM4 Suicide plasmid. sacB; mobRP4; oriR6K; CmR [30] pSMP22 Suicide plasmid. groESL promoter, ori T, bla, sacB [29] pSMP50CAM 432 bp fragment of pilA including a chlorampenicol resistance cassette cloned into pSMP22. CmR This study pAL12 2072 bp fragment of approximately 1 kb upstream and 1 kb downstream of pilC cloned in XbaI and SalI site of pDM4.

Therefore, PTL-induced apoptosis was confirmed to be caspase-dependent. Discussion

Pancreatic cancer is a major unsolved health problem because of its biological aggressiveness. In the last decade, traditional clinical cancer therapy regimens as surgical tumor resection, cytotoxic chemotherapy, and radiation therapy have been supplemented with individualized targeted therapies directed against molecular determinants of the tumor. In spite of improved multimodal therapeutic regimens, 5 year survival does not exceed 5 percent. Inherent or acquired resistance towards PKC412 ic50 cytotoxic agents, ionizing radiation, or both, is one of the hallmarks of biological aggressiveness of pancreas cancer as a solid tumor. To develop a new chemotherapeutic agent is still a clinical major concern as well as the better understanding of etiopathogenesis and molecular biology of pancreatic cancer. NF-kB is ubiquitous and can be detected in the cytoplasm of many cell types. Several researches have indicated that constitutive NF-kB activation may conduce to pancreatic tumorigenesis [15, 16]. Hence, the chemotherapeutic potential of NF-kB inhibitors should be evaluated.

PTL is one of the traditional medicines extracted from medical herb Feverfew ARRY-162 concentration in European and American. Studies have shown that PTL targets NF-kB via inhibition of the upstream regulator IkB kinase (IKK) [17] which phosphorylates IkB and targets it for proteasomal degradation. PTL and its analogues have recently been shown to inhibit proliferation, suppress invasiveness and induce apoptosis of several ioxilan human cancer cells [4–6, 18]. Further studies indicate that in vitro and vivo PTL and its analogues-induced growth inhibition and apoptosis is associated with NF-kB pathway, and the effect is more significant combined with COX inhibitor [12, 19]. But the detailed and precise mechanism underlying PTL induced apoptosis remains unclear which attracted our interest. In our study it was found that PTL buy CFTRinh-172 significantly inhibited

growth of BxPC-3 cells. MTT assay demonstrated a dramatic loss of viability of cancer cell which was treated with PTL in a dose-dependent fashion. Next PTL-induced apoptosis was observed. Flow cytometry indicated that PTL conspicuously induced apoptosis which was confirmed by DNA fragmentation analysis. Meanwhile the migration and invasion assay indicated that PTL effectively suppressed cancer cell movement. Data mentioned above demonstrated PTL might be a novel chemotherapeutic agent. In order to explore the molecular mechanism of PTL-induced apoptosis in BxPC-3 cell, several genes were detected. Wang et al [20] demonstrated that combination therapy with PTL and arsenic trioxide inhibited the growth of pancreatic cancer cells via the mitochondrial pathway. Researches have reported that Bcl-2 family members are associated with mitochondria-related apoptosis [21, 22].

pylori strain was equivalent to that exhibited by a final concentration of 1.2 μg/ml of activated purified find more VacA [42,45]. G. mellonella

killing assays To assess the virulence of H. pylori in vivo using the G. mellonella insect model of infection [26], caterpillars weighing between 200 mg and 400 mg and maintained on wood chips in the dark at 8-10°C were employed in all assays. No ethical approval was required for the study because there was no use of a mammalian model of infection and animal house. Briefly, bacteria were harvested from a culture by rolling a moistened swab over the plate into 1 ml of phosphate-buffered saline (PBS) and adjusted to an OD450 of 1.0. A Hamilton syringe was used to inject 10 μl aliquots of serially diluted bacterial suspensions (from 1 × 107 to 1 × 104 CFUs) or BCFs collected from 1 × 106 CFUs into the hemocoel via the left proleg of each larva. Bacterial colony counts on 10% blood Columbia agar plates under microaerophilic conditions

were used to confirm all inocula of either bacterial suspensions or BCFs. Control larvae were either injected with 10 μl of PBS in order to measure any potential lethal effects of the injection process, or not injected to measure the effects of the incubation procedure. Ten G. mellonella larvae were infected for each experimental condition, with each experiment click here repeated at least 3 times. After injection, larvae were incubated in petri dishes at 37°C in standard aerobic conditions and survival AZD6738 manufacturer was recorded at 24 h intervals for 96 h. Larvae were considered dead when they displayed no movement in response to gentle prodding with a pipette tip [31]. To determine the numbers of viable bacteria in larvae at 0, 24, 48 and 72 h post-infection, larvae were chilled on ice for 10 min. The bottom 2 mm of each larva was aseptically removed and haemocoel was drained into a sterile 1.5 ml microcentrifuge tube. For enumeration haemocoel was serially diluted in PBS and the bacterial load per larva was quantified by enumeration of CFUs on Columbia Blood Agar plates (CBA) supplemented with 10% defibrinated horse

blood, 1% Vitox and Skirrow’s supplement and incubating under microaerophilic conditions in anaerobic jars with microaerobic System CampyGen (Oxoid) at 37°C for 48-72 h. Flow cytometry analysis of G. mellonella hemocytes Myosin Hemocytes were prepared from hemolymph of G. mellonella larvae as described by Bergin et al. [24]. Plasma membrane asymmetry existing in living cells is lost on apoptosis and it is commonly detected with probes, like Annexin V, interacting strongly and specifically with phosphatidylserine. In order to assess apoptosis induction on G. mellonella hemocytes, (FITC)-conjugated annexin V (Pharmingen San Diego, CA) staining has been performed as described [46]. Cells were washed in cold Annexin V buffer (10 mM HEPES, 140 mM NaCl, 2.5 mM CaCl2) prior to treatment with FITC-labeled Annexin V (BD, Milan, Italy) for 15 min at room temperature.

Transcript from the bat genes is present in

the WT strain but undetectable in the ΔbatABD mutant, as expected. In the ΔbatA mutant strain, only the batA transcript is undetectable, but transcripts from the downstream ORFs, including batB and batD, were detected. Although the arrangement of the 11 genes suggest they may be co-transcribed in an operon, the deletion of the bat genes does not eliminate transcript from the SAHA mouse downstream ORFs and we hypothesize that each gene has an independent promoter. Interestingly, even ORFs immediately downstream of the deleted genes had observable levels of transcript, even though their promoter regions were most likely located in the deleted sequences. However, the levels of transcript from the downstream genes were significantly lower in the mutant strains compared to transcript levels in the WT: htpG transcript levels were 3.7-fold lower in the ΔbatABD strain, and batB Sapanisertib transcript levels were >12-fold lower in the ΔbatA mutant. Figure 3 Quantitative RT-PCR analysis of the bat locus and downstream genes. Gene targets are shown below the PD173074 supplier corresponding section of the bar-graph using specific primer-probe sets for each gene (Table 1). Transcript from each gene was normalized to 104 copies of flaB transcript

from the respective strain. –X–, indicates deletion of the corresponding gene indicated above. Values represent the mean of triplicate reactions ± the standard error. Unpaired T test with Welch’s correction was used to determine significant differences between two groups (e.g. batB transcript levels between WT and ΔbatA mutant strains). For statistical analysis of more than 2 groups (such as comparisons of gene transcripts between WT, ΔbatA mutant and ΔbatABD mutant strains), one-way analysis of variance (ANOVA) with the

Bonferroni’s post test was applied. P values < 0.0001 are denoted by ***. Morphology and growth rate of bat mutants are equivalent to wild-type The signal sequence of BatD suggests a periplasmic or membrane-associated location for at least one member of this protein family. We therefore examined whether the absence of Bat proteins affected cellular Branched chain aminotransferase shape or structure. L. biflexa morphology was assessed by scanning and transmission electron microscopy, including negative stains and freeze-substitution fixation to retain a more native state of the cells. As shown in representative images in Figure 4A, no morphological or ultrastructural differences were observed between the WT and mutant strains by any of these analyses. Figure 4 Deletion of bat loci does not alter morphology or growth of L. biflexa . (A) Electron micrographs of WT and mutant L. biflexa strains. No difference was observed in the morphology of the mutant strains relative to the WT (batA images not shown). Top panel – SEM images of L.

To characterize the extracellular fungal proteins associated with the buy EPZ-6438 silver nanoparticles, SDS-PAGE was used. Cell filtrate (CF) was isolated by centrifugation from mycelial mat slurry. Protein profiles of cell filtrate clearly showed the presence of several bands of molecular weights between 50 and over 116 kDa (Figure 7, lane 2). Some of these proteins may be responsible for synthesis as well as stability of the silver nanoparticles. Treatment of silver nanoparticles with 1% SDS in boiling water bath for 10 min resulted in

detachment of the capping protein(s) from the nanoparticles. When analyzed by SDS-PAGE, the boiled sample showed an intense band of 85 kDa (Figure 7, lane 4) which was not seen when the nanoparticles were not boiled with sample buffer (Figure 7, lane 3). This band is similar to the protein band present in Selleck LGX818 the cell filtrate (Figure 7, lane 2). It is likely that this 85-kDa protein acts as a capping material and confers stability to the silver nanoparticles. Detection of extracellular proteins responsible for selleck chemicals llc synthesis and stability

of silver nanoparticles were also reported from a few other literatures [14, 36]. The presence of natural capping proteins eliminates the postproduction steps of capping which is necessary for most of applications of nanoparticles in the field of medicine. Figure 7 SDS-PAGE analysis of capping protein around the silver nanoparticles. Lane 1, molecular size marker; lane 2, extracellular proteins in the cell filtrate; lane 3, nanoparticles loaded without boiling show no protein band; and lane 4, nanoparticles after boiling with 1% SDS loading buffer show a major 85-kDa capping protein. Genotoxic effect of silver nanoparticles against plasmid DNA Agarose gel electrophoresis

of plasmid pZPY112 treated Tangeritin with different concentrations of silver nanoparticles showed a dose-dependent induction of DNA strand break, characterized by increased degradation of supercoiled form to relaxed circle to linear forms with increase in concentration of nanoparticles used (Figure 8). DNA strand scission induced by silver nanoparticle leads to gradual degradation in the amount of both linear and supercoiled DNA and appearance of extra bands lower in the gel which are the resultant fragmented DNA (Figure 8). Besides their antimicrobial activity, silver nanoparticles have been shown to be potentially genotoxic by in vivo and in vitro assays [37]. In the present study, the genotoxicity exhibited by silver nanoparticles was demonstrated by degradation of plasmid posttreatment even with low concentrations of the nanoparticles. Such genotoxic activities of nanoparticles were reported earlier in case of carbon nanotubes [38] where degree of DNA degradation was directly proportional to the concentration of nanoparticles. A proposed mechanism of DNA damage is through generation of singlet oxygen as reported in the case of copper nanoparticles [30].

01) and HLHK9∆ureA/arcA1/arcA2 (p < 0.01) (Figure  3C), and the reduction trend became more pronounced after 3 and 5 h incubation (Figure  3D). At pH 2 and 3, the survival counts of HLHK9∆ureA started to decrease (P <0.05), whereas there were dramatic decreases in the survival counts of HLHK9∆arcA1/arcA2 (p < 0.001) and triple knockout

mutant HLHK9∆ureA/arcA1/arcA2 strains, which were almost MK 1775 completely killed (p < 0.001) (Figure  3C). These showed that the ADI pathway of L. hongkongensis played a more important role than the urease in resisting acidic environments. Intracellular survival in J774 macrophages and mRNA expression level analyses Survival selleck chemicals of wild type L. hongkongensis HLHK9, HLHK9∆ureA, HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 in J774 macrophages were shown in Figure  4A. Survival of HLHK9∆ureA/arcA1/arcA2 and HLHK9∆arcA1/arcA2 in macrophages were markedly decreased (p < 0.001 and p < 0.01 respectively) but that of HLHK9∆ureA was slightly decreased (p < 0.05), compared to wild type L. hongkongensis HLHK9. The decrease of survival was more prominent in HLHK9∆ureA/arcA1/arcA2, compared to HLHK9∆arcA1/arcA2 (p < 0.05) and HLHK9∆ureA (p < 0.01); and in HLHK9∆arcA1/arcA2,

compared to HLHK9∆ureA (p < 0.05). Given the above results, we further investigated the expression level of ADI genes (arcA1 and arcA2) and ureA gene of wild type L. hongkongensis HLHK9 survived in macrophages using real-time quantitative RT-PCR assay. At 8 h post infection, the mRNA levels of arcA1, arcA2 and ureA genes were markedly increased this website compared to those at 2 h post infection (p < 0.05, p < 0.01 Pregnenolone and p < 0.05 respectively) (Figure  4B). Figure 4 Intracellular survival assays in J774 macrophages. A, Recovery rates of wild type L. hongkongensis HLHK9, HLHK9∆ureA,

HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 in J774 macrophages. B, Expression level of ADI genes (arcA1 and arcA2) and ureA gene of HLHK9 in macrophages. Error bars represent means ± SEM of three independent experiments. An asterisk indicates a significant difference (*, p < 0.05; **, p < 0.01; ***, p < 0.001). Survival of L. hongkongensis strains in BALB/c mice To further investigate the role of urease and ADI pathway in acid tolerance of L. hongkongensis, we compared the survival ability of HLHK9, mutant strains HLHK9∆ureA, HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 after transit through the stomach of mice. Using this mouse model, HLHK9∆ureA exhibited similar survival abilities as HLHK9 (Figure  5). In contrast, the viable counts of HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 were reduced by 1.2-log and 1.3-log respectively, compared to that of HLHK9 (p < 0.01) (Figure  5). This also indicated that the ADI pathway played a more significant role than urease in the survival of L.

J Gen Virol 2010, 91:463–469.PubMedCrossRef Belinostat supplier 39. Pan H, Xie J, Ye F, Gao SJ: Modulation of Kaposi’s sarcoma-associated herpesvirus infection and replication by MEK/ERK, JNK,

and p38 multiple mitogen-activated protein kinase pathways during primary infection. J Virol 2006, 80:5371–5382.PubMedCrossRef 40. Xie J, Ajibade AO, Ye F, Kuhne K, Gao SJ: Reactivation of Kaposi’s sarcoma-associated herpesvirus from latency requires MEK/ERK, JNK and p38 multiple mitogen-activated protein kinase pathways. Virology 2008, 371:139–154.PubMedCrossRef 41. Roberts PJ, Der CJ: Targeting the Raf-MEK-ERK mitogen-activated protein kinase cascade CHIR98014 in vitro for the treatment of cancer. Oncogene 2007, 26:3291–3310.PubMedCrossRef 42. Ford PW, Bryan BA, Dyson OF, Weidner DA, Chintalgattu V, Akula SM: Raf/MEK/ERK signalling triggers reactivation of Kaposi’s sarcoma-associated herpesvirus latency. J Gen Virol 2006, 87:1139–1144.PubMedCrossRef 43. Cohen A, Brodie C, Sarid R: An essential role of ERK signalling in TPA-induced reactivation of Kaposi’s sarcoma-associated herpesvirus. J Gen Virol 2006, 87:795–802.PubMedCrossRef 44. Yu F, Harada JN, Brown HJ, Deng H, Song MJ, Wu TT, Kato-Stankiewicz J, Nelson CG, Vieira J, Tamanoi F, Chanda SK, Sun R: Systematic identification of

cellular signals reactivating Kaposi sarcoma-associated herpesvirus. PLoS Pathog 2007, 3:e44.PubMedCrossRef 45. Lee N, Bae S, Kim H, Kong JM, Kim HR, Cho BJ, Kim SJ, Seok SH, Hwang YI, Kim S, Kang JS, Lee WJ: Inhibition of lytic reactivation of Kaposi’s sarcoma-associated herpesvirus by alloferon. Antivir Ther 2011, 16:17–26.PubMedCrossRef Authors’ contributions DQ, NF and WF carried out

MYO10 the experiments. DQ drafted the manuscript. XM, QY and ZL participated in Western blot and IFA. YZ and JZ participated in discussion in preparing the manuscript. CL designed the study and revised the manuscript. All authors read and approved the final manuscript.”
“Background Traditionally, biodiversity has been explained by the niche partitioning hypothesis, which stresses that coexisting species are differentiated by niche dimensions. On the other hand, the neutral hypothesis proposes that species at the same trophic level colonizing the same space are functionally equivalent [1], because different species have the same likelihood of dispersal, death and birth. Assessment of plant communities has yielded controversial results, some seemed to support the neutral hypothesis [1–3], whereas others did not [4, 5]. Attempts have been made to resolve the controversy between the traditional and the neutral hypotheses by integrating stochastic factors into MEK inhibitor niche-based models [6].

A cohort profile describing the study sample, research objectives and attrition

has been documented by Richter et al. [16]. An adolescent’s ethnic classification was defined by the race classification currently used in South Africa for demographic and restitution purposes. The South African government currently classifies race into black (B; ethnic Africans), white (W; Europeans, Jews and Middle Easterners), coloured or mixed ancestry (MA; mixed race) and Indian (South Asian), and only adolescents whose parents were classified as being of the same ethnic group were included. Data from 1,389 adolescent–biological mother pairs were analysed for this study. The ethnic LY333531 breakdown of the study sample was predominantly B (1,170 (84.2 %)), with the remainder selleck compound of the cohort being made up of W (91 (6.6 %)) and MA (128 (9.2 %)). Indian adolescents and their mothers were excluded as the number of participants was too few to make meaningful comparisons. Children who had chronic diseases such as rheumatoid arthritis, epilepsy and asthma were excluded from the data analyses, as the use of certain medications and immobility are associated risk factors for low bone mass and may increase the incidence of fractures. All subjects provided assent and their parents/guardian INK1197 order provided written, informed

consent. Ethical approval for the study was obtained from the University of the Witwatersrand Committee for Research on Human Subjects. Fracture questionnaire A fracture questionnaire was completed by each adolescent with the assistance of his/her parent or caregiver at 15 and 17/18 years of age. The questionnaire at age 15 included information on previous fractures from birth until 15 years of age, including site of fracture with the aid of a skeletal diagram, and the causes and age at fracture. At age 17/18, the fracture questionnaire included information on fractures that had occurred since their previous questionnaire.

Mothers/caregivers also completed a questionnaire on fractures occurring since birth in the adolescent’s sibling(s). Biological mothers completed questionnaires on their own fractures prior to the age of 18 years. Due to the retrospective nature of the fracture data collection, the fractures could not be verified by radiographs. Anthropometric Inositol monophosphatase 1 measurements and dual-energy X-ray absorptiometer-derived parameters Anthropometric measurements and bone mass data on the subjects at the age of 17/18 years were used for this study. Biological mothers’ anthropometric data and bone mass measurements had been collected over 2 years when the adolescents were approximately 13 years of age. Height was measured to the nearest millimetre using a stadiometer (Holtain, Crosswell, UK). Weight was measured to the last 100 g using a digital scale (Dismed, Halfway House, South Africa), with participants wearing light clothing and no shoes.

SAE carried out the molecular genetic work and drafted the manuscript. Both authors read and approved the final manuscript.”
“Background Brucellosis is primarily a zoonotic disease, caused by members of the genus Brucella, which currently constitutes several species based on pathogenicity, host preferences and phenotypic characteristics: E1 Activating inhibitor B. abortus (cattle), B. canis (dogs), B. RG-7388 melitensis (goats), B. suis (pigs), B. ovis (rams), B. neotomae (desert rats), B. ceti and

B. pinnipedialis (marine mammals), and B. microti (common vole) [1–6]. Recently, a novel species, Brucella inopinata, associated with a human infection has been recognized as the newest member of the genus Brucella [7, 8]. In early 1985, whole genome hybridization analysis studies revealed a high degree of genetic homology among the Brucella species, which led to the proposal that the genus Brucella was a mono-specific species with B. melitensis being the primary species and all others as sub-species and biovars [9–11]. However, due to the limited acceptability of the one-species concept, the traditional classification of Brucella OSI 906 spp. based on phenotypic characteristics has been re-instated by the Brucella Taxonomy Subcommittee in 2006 [3].

Brucella are facultative intracellular pathogens that infect many organs and soft tissues, including mammary glands. Infection frequently results in abortion, low milk production and fetal death in animals [2, 12–16]. Brucellosis in humans is mostly caused by B. abortus, B. melitensis, B. suis, and sometimes B. canis [14, 17–19], and is commonly associated with the consumption of unpasteurized dairy products, meat from infected animals and exposure to infected animal tissues or laboratory transmission [1, 2, 20]. Human brucellosis is a chronic debilitating infection with a very broad clinical picture potentially affecting any major organ, including the lung, causing varying respiratory symptoms [20]. Respiratory infections in humans caused by Brucella spp. is a rare manifestation with reports describing multifocal abscesses or nodules, hilar adenopathy and hemorrhagic pleural effusion with resolution

by antimicrobial therapy and lung decortications [21–26]. Most pulmonary brucellosis RVX-208 cases were found in farmers handling infected meat or travelers who consumed raw infected animal meat or unpasteurized milk products while visiting countries endemic for brucellosis [26, 27]. We report the isolation and identification of an unusual gram-negative, non-motile Brucella-like coccoid bacillus (BO2) isolated from a lung biopsy in a 52-year-old male in Australia with a history of chronic destructive pneumonia. The patient traveled worldwide but denied any common risk factors associated with brucellosis. Both biochemical and molecular characteristics of the BO2 strain have demonstrated unique similarity with a recently described B.

To successfully proceed with the development and improvement of such systems, a comprehensive see more understanding is required and therefore a detailed characterization should be addressed. This is not an easy task since the downscaling tendency will require a characterization down to nanoscale where big challenges like confinement can occur. As a result, effects confined down

to nanoscale can play Dactolisib a major and defining role in the overall performance of future devices. Therefore, not only the access of nanoscale is strongly required, but also the corresponding understanding is a key factor for reaching a success. Addressing these two aspects, the scanning probe microscopy techniques exhibit strong versatility. In particular, for interconnect systems, the electric characterization which gives an insight into the CNT/bottom

line contact quality is of great importance. Multi-walled CNT (MWCNT)-based via interconnect systems are mainly characterized in the literature using classical electrical measurements where the entire via is contacted using a top metal electrode. It is obvious where the problem lies in this configuration. The outcome of the study tells nothing about fluctuations inside the via itself. The interpretation of such results is rather blind relative to a possible inhomogeneous internal performance. Via a (nano)characterization of learn more such systems by conductive atomic force microscopy (c-AFM), this issue is not overlooked. Moreover, c-AFM gives the opportunity to address single CNTs earning undeniable superiority over the classical electrical measurements. While general information can be collected over an extended CNT array using the so-called current mapping, individual CNTs can be addressed in detail using current–voltage (I V) studies. The facility is crucial as the downscaling tendency boosts the importance of the CNT/metal contacts in the ultimate nanoscaled devices with Ceramide glucosyltransferase a strong impact over

the final performance. Therefore, c-AFM was applied in this work to address the electric characterization of vertically aligned MWCNT arrays grown on a copper-based metal line. Methods Vertically aligned MWCNT arrays were grown by chemical vapour deposition on a copper-based conductive metal line as comprehensively described in [8, 15]. The copper-based metal line is a layer stack where Ta was used as the top layer. Moreover, TaN was used as the barrier layer to inhibit copper diffusion into the Ni catalyst layer. It was shown that the lack of such a diffusion barrier would strongly affect the quality of the CNT vertical growth [8]. All data shown within this work were recorded under ambient conditions using a 5500 AFM from Agilent Technologies (Santa Clara, CA, USA). N-type (phosphorus-doped) silicon-etched AFM probes from MikroMasch (Wetzlar, Germany) with a nominal uncoated tip radius of 10 nm were used for tapping-mode imaging.