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Background: Rhizobial surface polysaccharides are important molecular determinants required for successful symbiosis with legumes. In Sinorhizobium ( Ensifer) meliloti Rm41, the rkp-2 region is involved in the biosynthesis of K-antigen polysaccharide (KPS) and lipopolysaccharide (LPS). This region is composed of two genes, lpsL and rkpK, which are respectively responsible for the production of galacturonic and glucuronic acid. Results: In this work, we show that in S. ( Ensifer) fredii HH103 these genes do not form a transcriptional unit and that the transcriptional rate of rkpK is much higher than that of lpsL. Inactivation of each of these genes resulted in alterations in LPS, but did not affect KPS production, which is in agreement with the lack of uronic acids in S. fredii HH103 KPS. Mutation of rkpK also impaired HH103 exopolysaccharide (EPS) production, most probably due to the presence of glucuronic acid in HH103 EPS, as well as increased bacterial autoaggregation and osmosensitivity and decreased biofilm formation on plastic surfaces. Inactivation of rkpK affected negatively symbiosis with cowpea but not with soybean. Mutation of lpsL led to a complete symbiotic impairment with cowpea, whereas soybean plants inoculated with this mutant only formed pseudonodules. In both plants, the lpsL mutant showed defects in root infection. Conclusion: These results confirm the symbiotic importance of HH103 LPS in symbiosis with legumes. [ABSTRACT FROM AUTHOR]

We present a polyad-preserving algebraic approach to molecular structure and, as an application, we fit the model parameters to reproduce an extensive experimental data set of vibrational energies of carbon dioxide in its ground electronic state. The data set includes levels with vibrational angular momentum ℓ = 1, ...,6 and some recently obtained term values that have not been previously considered. The obtained results are close to experimental uncertainty and we compare the results obtained making use of the three most common polyad schemes that can be found in the literature for this molecular species. Graphical abstract: [ABSTRACT FROM AUTHOR]

This work presents the development of a portable, wireless activity monitoring system for the estimation of biomechanical gait parameters. The system uses a pair of instrumented insoles able to measure pressure from different points of the foot including four commercial piezoresistive pressure sensors and a three-axis accelerometer, all together integrated in the insole to determine foot forces during stance and swing phases. The system includes two kinds of analysis data, one on line with a RF communications to a computer, and another off line reading the data from SD memory card. Our system has been validated and tested in different trials, extracting several features during walking for ten participants by means of the combined information from the two kinds of sensors. With the combined data from the complete set of sensors, we can obtain highly valuable information on foot movement during the non-contact period, such as supination or pronation characteristics or anomalous movement during flight time. From our preliminary results, the variation of the lateral acceleration of the foot seems to be correlated with the amount of supination. [ABSTRACT FROM AUTHOR]

We report the modeling, and geometrical and electrical characterization, of inkjet and screen-printed patterns on different polymeric substrates for use as antennas in radio-frequency identification (RFID) applications. We compared the physical and electrical characteristics of two silver nanoparticle-based commercial inkjet-printable inks and one screen-printable silver paste, when deposited on polyimide (PI), polyethylene terephthalate (PET), and polyetherimide (PEI) substrates. First, the thickness of the inkjet-printed patterns was predicted by use of an analytical model based on printing conditions and ink composition. The predicted thickness was confirmed experimentally, and geometrical characterization of the lines was completed by measuring the root-mean-square roughness of the patterns. Second, direct-current electrical characterization was performed to identify the printing conditions yielding the lowest resistivity and sheet resistance. The minimum resistivity for the inkjet-printing method was 8.6 ± 0.8 μΩ cm, obtained by printing four stacked layers of one of the commercial inks on PEI, whereas minimum resistivity of 44 ± 7 μΩ cm and 39 ± 4 μΩ cm were obtained for a single layer of screen-printed ink on polyimide (PI) with 140 threads/cm mesh and 90 threads/cm mesh, respectively. In every case, these minimum values of resistivity were obtained for the largest tested thickness. Coplanar waveguide transmission lines were then designed and characterized to analyze the radio-frequency (RF) performance of the printed patterns; minimum transmission losses of 0.0022 ± 0.0012 dB/mm and 0.0016 ± 0.0012 dB/mm measured at 13.56 MHz, in the high-frequency (HF) band, were achieved by inkjet printing on PEI and screen printing on PI, respectively. At 868 MHz, in the ultra-high-frequency band, the minimum values of transmission loss were 0.0130 ± 0.0014 dB/mm for inkjet printing on PEI and 0.0100 ± 0.0014 dB/mm for screen printing on PI. Although the resistivity achieved is lower for inkjet printing than for screen printing, RF losses for inkjetted patterns were larger than for screen-printed patterns, because thicker layers were obtained by screen printing. Finally, several coil inductors for the HF band were also fabricated by use of both printing techniques, and were used as antennas for semi-passive smart RFID tags on plastic foil capable of measuring temperature and humidity. [ABSTRACT FROM AUTHOR]

The Sinorhizobium fredii HH103 rkp- 1 region, which is involved in capsular polysaccharide (KPS) biosynthesis, is constituted by the rkpU, rkpAGHIJ, and kpsF3 genes. Two mutants in this region affecting the rkpA (SVQ536) and rkpI (SVQ538) genes were constructed. Polyacrylamide gel electrophoresis and H-NMR analyses did not detect KPS in these mutants. RT-PCR experiments indicated that, most probably, the rkpAGHI genes are cotranscribed. Glycine max cultivars (cvs.) Williams and Peking inoculated with mutants SVQ536 and SVQ538 showed reduced nodulation and symptoms of nitrogen starvation. Many pseudonodules were also formed on the American cv. Williams but not on the Asiatic cv. Peking, suggesting that in the determinate nodule-forming S. fredii-soybean symbiosis, bacterial KPS might be involved in determining cultivar-strain specificity. S. fredii HH103 mutants unable to produce KPS or exopolysaccharide (EPS) also showed reduced symbiotic capacity with Glycyrrhiza uralensis, an indeterminate nodule-forming legume. A HH103 exoA-rkpH double mutant unable to produce KPS and EPS was still able to form some nitrogen-fixing nodules on G. uralensis. Thus, here we describe for the first time a Sinorhizobium mutant strain, which produces neither KPS nor EPS is able to induce the formation of functional nodules in an indeterminate nodule-forming legume. [ABSTRACT FROM AUTHOR]

In this work we studied how biotic and abiotic stresses can alter the pattern of flavonoids exuded by Osumi soybean roots. A routine method was developed for the detection and characterization of the flavonoids present in soybean root exudates using HPLC-MS/MS. Then, a systematic screening of the flavonoids exuded under biotic stress, the presence of a plant growth promoting rhizobacterium, and salt stress was carried out. Results obtained indicate that the presence of Chryseobacterium balustinum Aur9 or 50 mM NaCl changes qualitatively the pattern of flavonoids exuded when compared to control conditions. Thus, in the presence of C. balustinum Aur9, soybean roots did not exude quercetin and naringenin and, under salt stress, flavonoids daidzein and naringenin could not be detected. Soybean root exudates obtained under saline conditions showed a diminished capacity to induce the expression of the nodA gene in comparison to the exudates obtained in the absence of salt. Moreover, lipochitooligosaccharides (LCOs) were not detected or weakly detected when Sinorhizobium fredii SMH12 was grown in the exudates obtained under salt stress conditions or under salt stress in the presence of C. balustinum Au9, respectively. [ABSTRACT FROM AUTHOR]