FOXO transcriptional activity is associated with response to chemoradiation in EAC.

In this study we aimed to investigate signaling pathways that drive therapy resistance in esophageal adenocarcinoma (EAC). Paraffin-embedded material was analyzed in two patient cohorts: (i) 236 EAC patients with a primary tumor biopsy and corresponding post neoadjuvant chemoradiotherapy (nCRT) resection; (ii) 66 EAC patients with resection and corresponding recurrence. Activity of six key cancer-related signaling pathways was inferred using the Bayesian inference method. When assessing pre- and post-nCRT samples, lower FOXO transcriptional activity was observed in poor nCRT responders compared to good nCRT responders (p = 0.0017). This poor responder profile was preserved in recurrences compared to matched resections (p = 0.0007). PI3K pathway activity, inversely linked with FOXO activity, was higher in CRT poor responder cell lines compared to CRT good responders. Poor CRT responder cell lines could be sensitized to CRT using PI3K inhibitors. To conclude, by using a novel method to measure signaling pathway activity on clinically available material, we identified an association of low FOXO transcriptional activity with poor response to nCRT. Targeting this pathway sensitized cells for nCRT, underlining its feasibility to select appropriate targeted therapies.

Development of a multiperspective optical measuring system for investigating decaying switching arcs at the nozzle exit of circuit breakers.

High-voltage gas circuit breakers, which play an important role in the operation and protection of the power grid, function by drawing an arc between two contacts and then extinguishing it by cooling it using a transonic gas flow. Improving the design of circuit breakers requires an understanding of the physical processes in the interruption of the arc, particularly during the zero crossing of the alternating current (the point in time when the arc can be interrupted). Most diagnostic techniques currently available focus on measurement of current, voltage, and gas pressure at defined locations. However, these integral properties do not give sufficient insight into the arc physics. To understand the current interruption process, spatially resolved information about the density, temperature, and conductivity of the arc and surrounding gas flow is needed. Owing to the three-dimensional, unstable nature of the arc in a circuit breaker, especially near current zero, a spatially resolved, tomographic diagnostic technique is required that is capable of freezing the rapid, transient behavior and that is insensitive to the vibrations and electromagnetic interference inherent in the interruption of short-circuit current arcs. Here a new measurement system, based on background-oriented schlieren (BOS) imaging, is presented and assessed. BOS imaging using four beams consisting of white light sources, a background pattern, imaging optics, and a camera permits measurement of the line-of-sight integrated refractive index. Tomographic reconstruction is used to determine the three-dimensional, spatially resolved index of refraction distribution that in turn is used to calculate the density. The quantitative accuracy of a single beam of the BOS setup is verified by using a calibration lens with a known focal length. The ability of the tomographic reconstruction to detect asymmetric features of the arc and surrounding gas flow is assessed semiquantitatively using a nozzle that generates two gas jets, as described in [Exp. Fluids43, 241 (2007)EXFLDU0723-486410.1007/s00348-007-0331-1]. Experiments using a simple model of a circuit breaker, which provides optical access to an ∼1 kA arc that burns between two contacts and is blown through a nozzle system by synthetic air from a high pressure reservoir, are also described. The density in the decaying arc and surrounding gas flow is reconstructed, and the limitations of the technique, which are related to the temporal and spatial resolution, are addressed.

Burkholderia tropica sp. nov., a novel nitrogen-fixing, plant-associated bacterium.

In an ecological survey of nitrogen-fixing bacteria isolated from the rhizosphere and as endophytes of sugarcane, maize and teosinte plants in Brazil, Mexico and South Africa, a new phylogenetically homogeneous group of N(2)-fixing bacteria was identified within the genus Burkholderia. This polyphasic taxonomic study included microscopic and colony morphology, API 20NE tests and growth on different culture media at different pH and temperatures, as well as carbon source assimilation tests and whole-cell protein pattern analysis. Analysis of 16S rRNA gene sequences showed 99.2-99.9 % similarity within the novel species and 97.2 % similarity to the closest related species, Burkholderia sacchari. The novel species was composed of four distinct amplified 16S rDNA restriction analysis groups. The DNA-DNA reassociation values within the novel species were greater than 70 % and less than 42 % for the closest related species, B. sacchari. Based on these results and on many phenotypic characteristics, a novel N(2)-fixing species is proposed for the genus Burkholderia, Burkholderia tropica sp. nov., with the type strain Ppe8(T) (=ATCC BAA-831(T)=LMG 22274(T)=DSM 15359(T)). B. tropica was isolated from plants grown in geographical regions with climates ranging from temperate subhumid to hot humid.

Influence of nonylphenol on the microbial community of lake sediments in microcosms.

In this study the impact of nonylphenol, an estrogenic degradation product of alkylphenol polyethoxylates, on the microbial community structure in contaminated sediments of aquatic microcosms using in situ hybridization with fluorescently labeled oligonucleotides probes was investigated. A positive correlation between nonylphenol concentration and cell numbers of bacteria and microfungi as well as an increase in the numbers of active bacteria was found. However, the ratio between total microorganisms and active bacteria remained unchanged. A large fraction of the cells could be identified using group specific oligonucleotide probes. A slight change in the composition of the microbial community structure was observed, with Gram-positive bacteria with high DNA G + C-content becoming more abundant at higher concentrations of nonylphenol.

Limited effect of systemic beta-blockade on sympathetic outflow.

Central beta-adrenoreceptors may augment sympathetic outflow. We tested the hypothesis that beta-blockade attenuates central sympathetic outflow by inhibiting central adrenoreceptors. We studied 18 healthy controls (4 female, 14 male; age, 26+/-6 years, body mass index, 23+/-3 kg/m(2)). ECG, brachial, and finger arterial blood pressure, muscle sympathetic nerve activity, and respiration were measured continuously before and during complete beta-blockade. Subjects received a total intravenous dose of 0.21 mg/kg of propranolol in 15 minutes. Spontaneous baroreflex slopes were calculated using the sequence technique (BRSup, BRSdown). The sympathetic baroreflex slope was determined at baseline using phenylephrine and sodium nitroprusside infusions. The subjects underwent cold pressor testing before and during beta-blockade. The R-R interval increased from 861+/-119 ms at baseline to 952+/-141 ms during beta-blockade (P<0.01). Blood pressure was 117+/-9/65+/-8 mm Hg at baseline and 117+/-10/67+/-8 mm Hg during beta-Blockade (P=NS). beta-Blockade did not affect baroreflex sensitivity (BRSup: 21+/-10 versus 28+/-11 ms/mmHg, P<0.1; BRSdown: 17+/-8 versus 20+/-8 ms/mmHg, P=NS). Muscle sympathetic nerve activity increased significantly during beta-blockade (number of bursts/100 beats: 32+/-9 versus 40+/-14, P<0.05), compared with baseline. However, the operating points of the parasympathetic and sympathetic baroreflex during beta-blockade were on the baroreflex curves obtained at baseline. beta-Blockade blunted the heart rate response to cold pressor testing; blood pressure and muscle sympathetic nerve activity responses were similar. Our study demonstrates that propranolol does not cause an acute decrease in sympathetic activity in normotensive young subjects. This, observation is not consistent with an important tonic stimulatory effect of beta-adrenoreceptors in the brain.

Visualization of N-acylhomoserine lactone-mediated cell-cell communication between bacteria colonizing the tomato rhizosphere.

Given that a large proportion of the bacteria colonizing the roots of plants is capable of producing N-acyl-L-homoserine lactone (AHL) molecules, it appears likely that these bacterial pheromones may serve as signals for communication between cells of different species. In this study, we have developed and characterized novel Gfp-based monitor strains that allow in situ visualization of AHL-mediated communication between individual cells in the plant rhizosphere. For this purpose, three Gfp-based AHL sensor plasmids that respond to different spectra of AHL molecules were transferred into AHL-negative derivatives of Pseudomonas putida IsoF and Serratia liquefaciens MG1, two strains that are capable of colonizing tomato roots. These AHL monitor strains were used to visualize communication between defined bacterial populations in the rhizosphere of axenically grown tomato plants. Furthermore, we integrated into the chromosome of AHL-negative P. putida strain F117 an AHL sensor cassette that responds to the presence of long-chain AHLs with the expression of Gfp. This monitor strain was used to demonstrate that the indigenous bacterial community colonizing the roots of tomato plants growing in nonsterile soil produces AHL molecules. The results strongly support the view that AHL signal molecules serve as a universal language for communication between the different bacterial populations of the rhizosphere consortium.

Interaction between beta-adrenergic receptor stimulation and nitric oxide release on tissue perfusion and metabolism.

Nitric oxide (NO) may be an important modulator of sympathetic tone. We used im and sc microdialysis in humans to characterize the interaction of NO synthase inhibition and adrenoreceptor stimulation on tissue perfusion, metabolism, and norepinephrine release. Microdialysis probes were perfused with L- or D-nitro-L-arginine-methyl-ester (100 micromol/L) followed by incremental doses of isoproterenol, epinephrine, or nitroprusside. Blood flow was estimated based on the ethanol dilution technique. In muscle, the increase in blood flow with isoproterenol was abolished by L-NAME. The ethanol ratio was 0.03 +/- 0.011 with D-NAME and 0.075 +/- 0.014 with L-NAME during isoproterenol treatment (1 micromol/L). The effect was less pronounced in adipose tissue. The vasodilatory effect of nitroprusside was similar with D- and L-NAME. L-NAME augmented isoproterenol- and epinephrine-induced glycerol release. Dialysate glycerol during 1 micromol/L isoproterenol was 47 +/- 6.7 micromol/L with D-NAME and 72 +/- 15 micromol/L with L-NAME. In skeletal muscle, dialysate norepinephrine during 1 micromol/L isoproterenol treatment was 0.73 +/- 0.17 and 1.3 +/- 0.15 nmol/L with D- and L-NAME, respectively. We conclude that NO synthase inhibition attenuates beta(2)-adrenoreceptor-mediated vasodilation and enhances beta-adrenoreceptor-mediated lipolysis. These effects are in part mediated through an increase in interstitial norepinephrine concentrations. The data are consistent with the idea that in humans, NO is important in modulating and ameliorating sympathetic effects in peripheral tissues.

Design and application of new 16S rRNA-targeted oligonucleotide probes for the Azospirillum-Skermanella-Rhodocista-cluster.

The genera Azospirillum, Skermanella and Rhodocista form a phylogenetic subgroup within the alfa subclass of Proteobacteria. Based on comparative 16S rRNA sequence analysis a nested set of new oligonucleotide probes was designed. It comprises probes for the whole genus cluster Azospirillum-Skermanella-Rhodocista, for the Azospirilli subcluster I including A. lipoferum, A. doebereinerae, A. largimobile, A. brasilense and A. halopraeferens, for the Azospirilli subcluster II including A. amazonense, A. irakense and the genus Skermanella, for the genus Rhodocista as well as for all Azospirilli species or species cluster. The new probes allow a fast and reliable in situ identification of bacteria belonging to the Azospirillum-Skermanella-Rhodocista-cluster at different phylogenetic levels. The specificity of the new probes was tested with 56 strains of the Azospirillum-Rhodocista-Skermanella-cluster and selected reference cells from other genera by hybridising with the complete probe set. In addition, applications of the fluorescently labelled probes for in situ identification of isolates and for the in situ localisation of A. brasilense on maize roots were demonstrated using confocal laser scanning microscopy.

Genetic influences on baroreflex function in normal twins.

Blood pressure and heart rate are strongly influenced by genetic factors; however, despite the pivotal role of genetics in short-term cardiovascular regulation, little is known about the genetic contribution to baroreflex function. We assessed genetic influence on baroreflex sensitivity (BRS) in 149 twin pairs (88 monozygotic of age 33+/-13 years and BMI 23+/-4 kg/m(2) and 61 dizygotic of age 33+/-11 years and BMI 24+/-4 kg/m(2)). ECG and finger arterial blood pressures were measured continuously under resting conditions. BRS values were calculated by use of cross-spectral analysis (baroreflex slope calculated as mean value of transfer function between systolic blood pressure and the R-R interval in the low-frequency band [BRSLF] and baroreflex slope calculated as the mean value of transfer function between systolic blood pressure and R-R interval in the respiratory frequency band [BRSHF]) and the sequence technique (BRS+, BRS-). Heritability (h(2)) was estimated with a path-modeling approach. BRS values did not differ significantly between groups (monozygotic, BRSLF, 17+/-13; BRSHF, 21+/-18; BRS+, 19+/-16; and BRS-, 21+/-15, and dizygotic, BRSLF, 16+/-9; BRSHF, 20+/-14; BRS+, 18+/-10; and BRS-, 20+/-11 ms/mm Hg), and were significantly correlated (P:<0.001). When variances and covariances for monozygotic and dizygotic twins were compared, significant correlations were found for BRS in monozygotic (range, r=0.38 to 0.48) but not in dizygotic twin pairs (r=-0.03 to 0.09). Thus, BRS is heritable; the variability can be explained by genetic influences (P:<0.01; h(2) range, 0.36 to 0.44). The genetic influence on BRS remained strong after correction for BMI and blood pressure. Therefore, BRS is strongly genetically determined, probably by different genes than are resting blood pressure and BMI.

Herbaspirillum frisingense sp. nov., a new nitrogen-fixing bacterial species that occurs in C4-fibre plants.

The enrichment of nitrogen-fixing bacteria from the C4-fibre plants, Spartina pectinata, Miscanthus sinensis, Miscanthus sacchariflorus and Pennisetum purpureum, with nitrogen-free semi-solid media led to the isolation of Herbaspirillum-like strains among other diazotrophic bacteria. On the basis of physiological properties, phylogenetic analysis comparing 16S rDNA sequences and DNA-DNA hybridization experiments of chromosomal DNA the new isolates could be grouped together in a new species with the proposed name Herbaspirillum frisingense sp. nov. Morphological characteristics, such as cell size and shape, colony appearance, motility and flagellation are largely identical to the known species Herbaspirillum rubrisubalbicans and Herbaspirillum seropedicae. On the basis of utilization of adipate (-), N-acetyl-D-glucosamine (+), meso-erythritol (-), L-rhamnose (-) and meso-inositol (-) Herbaspirillum frisingense sp. nov. can be distinguished from other known Herbaspirillum spp. Nitrogen-fixing capability was examined by PCR amplification of the nifD gene and an acetylene reduction assay, and was found with all isolates tested. 16S rDNA sequence similarity to the other Herbaspirillum spp. is 98.5-99.1%. In genomic DNA-DNA hybridization experiments Herbaspirillum frisingense sp. nov. forms a homogeneous group with 70-100+/-10% similarity, clearly distinct from Herbaspirillum seropedicae and Herbaspirillum rubrisubalbicans with 1-34% similarity. 16S rRNA-targeted oligonucleotide probes, specific for the whole genus Herbaspirillum and for three Herbaspirillum species were designed and are suitable for fluorescence in situ hybridization. The DNA G+C content of Herbaspirillum frisingense sp. nov. is 63+/-2 mol%, in agreement with the values of 61-65% for the genus. PCR fingerprinting exhibits a consistent pattern for groups of strains isolated from the same plant, suggesting a low genomic diversity among bacteria inhabiting C4-gramineous plant tissues. Low genetic DNA diversity seems to be common between probable endophytic bacterial isolates of the same taxon. The type strain of Herbaspirillum frisingense sp. nov. is GSF30T (= DSM 13128T).

Azospirillum doebereinerae sp. nov., a nitrogen-fixing bacterium associated with the C4-grass Miscanthus.

A new group of nitrogen-fixing Azospirillum sp. bacteria was isolated from the roots of the C4-gramineous plant Miscanthus. Polyphasic taxonomy was performed, including auxanography using API galleries, physiological tests and 16S rRNA sequence comparison. The ability of the isolates to fix dinitrogen was evaluated by amplification of the nifD gene, immunodetection of the dinitrogenase reductase and acetylene-reduction assay. On the basis of these results, the nitrogen-fixing isolates represent a new species within the genus Azospirillum. Its closest phylogenetic neighbours, as deduced by 16S rDNA-based analysis, are Azospirillum lipoferum, Azospirillum largimobile and Azospirillum brasilense with 96.6, 96.6 and 95.9% sequence similarity, respectively. Two 16S rRNA-targeting oligonucleotide probes were developed which differentiate the new species from the other Azospirillum species by whole-cell fluorescence hybridization. Strains of the new species are curved rods or S-shaped, 1.0-1.5 microm in width and 2,0-3.0 microm in length, Gram-negative and motile with a single polar flagellum. Optimum growth occurs at 30 degrees C and at pH values between 6.0 and 7.0. No growth takes place at 37 degrees C. They have a respiratory type of metabolism, grow well on arabinose, D-fructose, gluconate, glucose, glycerol, malate, mannitol and sorbitol. They differ from A. largimobile and A. lipoferum by their inability to use N-acetylglucosamine and D-ribose, from A. lipoferum by their ability to grow without biotin supplementation and from A. brasilense by their growth with D-mannitol and D-sorbitol as sole carbon sources. Nitrogen fixation occurs in microaerobic nitrogen-limited conditions. For this species, the name Azospirillum doebereinerae sp. nov. is suggested, with strain GSF71T as the type strain (= DSM 13131T; reference strain Ma4 = DSM 13400). Its G+C content is 70.7 mol%.

Severely impaired baroreflex-buffering in patients with monogenic hypertension and neurovascular contact.

BACKGROUND: We identified a family with a monogenic syndrome of hypertension, brachydactyly, and neurovascular contact of the brain stem. Neurovascular contact of the ventrolateral medulla may lead to arterial hypertension by interfering with baroreflex function. METHODS AND RESULTS: In 5 patients with monogenic hypertension (18 to 34 years old), we conducted detailed autonomic function tests. Blood pressure during complete ganglionic blockade was 134+/-4.9/82+/-4.1 mm Hg and 90+/-6/49+/-2.4 mm Hg in patients and in control subjects, respectively. During ganglionic blockade, plasma vasopressin concentration increased 24-fold in control subjects and <2-fold in patients. In patients, cold pressor testing, hand-grip testing, and upright posture all increased blood pressure excessively. In contrast, muscle sympathetic nerve activity was not increased at rest or during cold pressor testing. The phenylephrine dose that increased systolic blood pressure 12.5 mm Hg was 8.0+/-2.0 microg in patients and 135+/-35 microg in control subjects before ganglionic blockade and 5.4+/-0.4 microg in patients and 13+/-4.8 microg in control subjects during ganglionic blockade. CONCLUSIONS: In patients with monogenic hypertension and neurovascular contact, basal blood pressure was increased even during sympathetic and parasympathetic nerve traffic interruption. However, sympathetic stimuli caused an excessive increase in blood pressure. This excessive response cannot be explained by increased sympathetic nerve traffic or increased vascular sensitivity. Instead, we suggest that baroreflex buffering and baroreflex-mediated vasopressin release are severely impaired.

rRNA probe-based cell fishing of bacteria.

We have developed a new, cultivation-independent, fast and flexible method for the rRNA-targeted probe-based enrichment of bacteria. The target cells were labelled by in situ hybridization with biotinylated polyribonucleotide probes. These probes were generated by in vitro transcription of amplified rDNA of a variable region in domain III of the 23S rRNA molecules. The probes were about 300 nucleotides in length and were labelled by incorporation of biotin-UTP during the transcription. Probes were hybridized with bacterial cells and incubated with paramagnetic streptavidin-coated particles. The labelled target cells can be separated in a column filled with steel wool inserted into the field of a permanent magnet. Unlabelled, non-target cells pass through the column, whereas labelled cells are retained. They were eluted from the column after removal of the magnetic field. Up to now, the method has been tested with mixtures of different pure cultures. For the first time, transcript probes have been used for the labelling of the target cells and for their specific separation. The enrichment of the target cells can be monitored by a streptavidin-fluorescein staining of the biotinylated target cells and/or by a subsequent in situ hybridization with fluorescently labelled oligonucleotide probes. Enrichment rates of up to 90-fold, depending on the original abundance of the cells of interest, could be determined. To demonstrate that the sorted cells were amenable to molecular analysis, we amplified and sequenced a part of the tuf gene of enriched Acinetobacter calcoaceticus cells.

Bacterial community dynamics during start-up of a trickle-bed bioreactor degrading aromatic compounds.

This study was performed with a laboratory-scale fixed-bed bioreactor degrading a mixture of aromatic compounds (Solvesso100). The starter culture for the bioreactor was prepared in a fermentor with a wastewater sample of a care painting facility as the inoculum and Solvesso100 as the sole carbon source. The bacterial community dynamics in the fermentor and the bioreactor were examined by a conventional isolation procedure and in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotides. Two significant shifts in the bacterial community structure could be demonstrated. The original inoculum from the wastewater of the car factory was rich in proteobacteria of the alpha and beta subclasses, while the final fermentor enrichment was dominated by bacteria closely related to Pseudomonas putida or Pseudomonas mendocina, which both belong to the gamma subclass of the class Proteobacteria. A second significant shift was observed when the fermentor culture was transferred as inoculum to the trickle-bed bioreactor. The community structure in the bioreactor gradually returned to a higher complexity, with the dominance of beta and alpha subclass proteobacteria, whereas the gamma subclass proteobacteria sharply declined. Obviously, the preceded pollutant adaptant did not lead to a significant enrichment of bacteria that finally dominated in the trickle-bed bioreactor. In the course of experiments, three new 16S as well as 23S rRNA-targeted probes for beta subclass proteobacteria were designed, probe SUBU1237 for the genera Burkholderia and Sutterella, probe ALBO34a for the genera Alcaligenes and Bordetella, and probe Bcv13b for Burkholderia cepacia and Burkholderia vietnamiensis. Bacteria hybridizing with the probe Bcv13b represented the main Solvesso100-degrading population in the reactor.