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Several Bands (several + bands)
Selected AbstractsShort-term dynamics of bacterial communities in a tidally affected coastal ecosystemFEMS MICROBIOLOGY ECOLOGY, Issue 2 2008Beate Rink Abstract Tidal effects on the composition of free-living (FL) and particle-associated (PA) bacterial communities were studied in a tidal flat ecosystem in the southern North Sea. Denaturing gradient gel electrophoresis targeting the 16S rRNA gene and the 16S rRNA of Bacteria, Bacteroidetes, Alphaproteobacteria and the Roseobacter clade was applied. Despite strong tidal variations in the quantity and, depending on the season, also the quality of suspended matter as well as variations in bacterial activity, the bacterial community composition remained rather stable. FISH showed some variations of the community composition, but these were not related to typical tidal situations. Variations were higher during tidal cycles in May and July compared with November. Bacteroidetes, Alpha - and Gammaproteobacteria constituted the majority of the bacterial communities but relative proportions of the different groups varied considerably. On particles, Betaproteobacteria were also detected to substantial proportions. The Roseobacter clade constituted up to 90% of FL but only 30% of PA Alphaproteobacteria. Banding patterns of the Bacteroidetes -specific amplicons, and in particular those targeting the 16S rRNA, revealed tidally induced effects, as several bands appeared or disappeared at distinct events such as slack water or resuspension. Sequencing of prominent bands revealed predominantly phylotypes reported previously from this ecosystem. [source] Studies on the resonance Raman spectra of polyaniline obtained with near-IR excitation,JOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2008Gustavo M. do Nascimento Abstract The effects of near-IR (NIR) laser power over the Raman spectra of poly(aniline) emeraldine salt (PANI-ES) and base (PANI-EB) were investigated. The reasons for the existence of several bands from 1324 to 1500 cm,1 in the Raman spectra of poly(aniline) obtained at NIR region were also studied. The bands from 1324 to 1375 cm,1 were associated to ,CN of polarons with different conjugation lengths and the bands from 1450 to 1500 cm,1 in Raman spectra of PANI emeraldine and pernigraniline base forms were correlated to ,CN modes associated with quinoid units having different conjugation lengths. The increase of laser power at 1064.0 nm causes the deprotonation of PANI-ES and the formation of cross-linking segments having phenazine and/or oxazine rings. For PANI-EB only a small spectral change is observed when the laser power is increased, owing to the low absorption of this form in the NIR region. Copyright © 2007 John Wiley & Sons, Ltd. [source] Vibrational spectra of bis(L -ornithinium) chloride nitrate sulfateJOURNAL OF RAMAN SPECTROSCOPY, Issue 1 2005S. Ramaswamy Abstract The Raman and infrared absorption spectra of 2(C5H14N2O22+)·Cl,·NO3,·SO42, crystal containing three anions were recorded at room temperature and were interpreted in the light of crystal structure data. The presence of a carbonyl group was identified. The carboxylic group was found to exist as COOH. The formation of OH···O, NH···O and NH···Cl asymmetric hydrogen bonds contributes considerably to the crystal cohesion and is responsible for the changes in the position and intensity of several bands. The vibrational spectra show that the anions were found to coordinate through hydrogen bonding interactions to other ligands in the crystal. The lattice wavenumbers of the halide radical (chlorine anion) were also assigned in terms of hydrogen bond vibrations. Copyright © 2004 John Wiley & Sons, Ltd. [source] Binding of the periodontitis associated bacterium Porphyromonas gingivalis to glycoproteins from human epithelial cellsMOLECULAR ORAL MICROBIOLOGY, Issue 5 2008U. Hallén Introduction:, In the present study we examined the ability of the periodontal pathogen Porphyromonas gingivalis to adhere to glycoconjugates on intact cells and to protein preparations of epithelial cells (KB cells). Methods:, The KB cell protein preparation was separated by sodium dodecyl sulfate,polyacrylamide gel electrophoresis and transferred to nitrocellulose membranes by Western blotting. The membranes were used in overlay assays with labeled P. gingivalis. Flow cytometry was used to analyze attachment of bacteria to intact KB cells. Results:, Glycoconjugate expression on the KB cells and in the protein preparation was confirmed. Binding was detected to several bands on the Western blots. Flow cytometry showed a distinct increase in fluorescence for strain FDC 381. Preincubation of the bacteria with mannose, fucose, N -acetylglucosamine and N -acetylgalactosamine inhibited the binding to KB cells by approximately 30% whereas preincubation with N -acetylneuraminic acid reduced the binding by 60%. Conclusion:, These results indicate that carbohydrate structures are involved in the binding process of P. gingivalis to oral epithelial cells and that neuraminic acid plays a significant role in the adhesion process. [source] Bacterial community profiles of endodontic abscesses from Brazilian and USA subjects as compared by denaturing gradient gel electrophoresis analysisMOLECULAR ORAL MICROBIOLOGY, Issue 1 2007J. C. Machado de Oliveira This study compared the bacterial community profiles of the microbiota associated with acute apical abscesses from Brazilian and USA patients using denaturing gradient gel electrophoresis (DGGE). DNA was extracted from purulent exudate aspirates and part of the 16S rRNA gene was amplified by polymerase chain reaction and separated by DGGE. The resulting banding patterns, which were representative of the bacterial community structures in samples from the two locations, were then compared. Distinct DGGE banding patterns were observed from different samples. Ninety-nine bands with distinct positions in the gels were detected, of which 27 were found only in the USA samples and 13 were exclusive to Brazilian samples. Four of the 59 shared bands showed very discrepant findings with regard to prevalence in the two locations. Cluster analysis of DGGE banding profiles showed a great variability in the bacterial populations associated with teeth with abscesses regardless of the geographical location. Two big clusters, one for each location, were observed. Other clusters contained a mixture of samples from the two locations. The results of the present study demonstrated a great variability in the bacterial community profiles among samples. This indicates that the bacterial communities of abscesses are unique for each individual in terms of diversity. The composition of the microbiota in some samples showed a geography-related pattern. Furthermore, several bands were exclusive for each location and others were shared by the two locations and showed great differences in prevalence. [source] Multiple vitellogenin-derived yolk proteins in gray mullet (Mugil cephalus): Disparate proteolytic patterns associated with ovarian follicle maturationMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 8 2008Haruna Amano PhD Abstract Disparate proteolytic patterns of yolk proteins, derived from three types of vitellogenin (VgA, VgB, and VgC), were observed in gray mullet. Immuno-biochemical analyses of extracts obtained from vitellogenic ovaries (VO) and ovulated eggs (OE) confirmed that a large proportion of VgA-derived lipovitellin (LvA) was degraded into free amino acids (FAAs) during ovarian follicle maturation. The maturation-associated alteration of VgB-derived Lv (LvB) involved only limited proteolysis; the heavy and light LvB chains were dissociated into at least three and one polypeptide fragments, respectively. The native mass of VgC-derived Lv (LvC) exhibited little difference between VO and OE, although it was apparent that the LvC was ,nicked' during maturation, resulting in the appearance of several bands in OE. Similar analyses confirmed that VgA-derived ,,-component (,,-cA) and VgB-derived ,,-c (,,-cB) decreased during maturation in both quantity and native mass, while phosvitin derived from either VgA (PvA) or VgB (PvB) appeared to be degraded into FAAs. The pattern of maturation-associated proteolysis of mullet yolk proteins is similar to that reported for other marine teleosts spawning pelagic eggs. However, the depository ratio of the three distinct types of Lv in the mullet VO appeared to be different from that estimated for another marine pelagophil, the barfin flounder. These results support a recent paradigm regarding the significance of Vg multiplicity upon successive physiological events in this group of fishes including the hydration of maturing oocytes, the acquisition of proper egg buoyancy, and the generation of requisite nutrient stocks for each stage of embryogenesis and larval development. Mol. Reprod. Dev. 75: 1307,1317, 2008. © 2008 Wiley-Liss, Inc. [source] Thermal quenching of luminescence and isovalent trap model for rare-earth-ion-doped AlNPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2007H. J. Lozykowski Abstract Investigations of the luminescent properties of Pr-, Eu-, Tb- and Tm-implanted AlN thin films at temperature in the range 9,830 K are reported. The temperature studies of photoluminescence and cathodoluminescence spectra revealed unexpectedly weak thermal quenching for all investigated rare earth (RE) ions. The maximum CL emission is observed from Eu (red) at 485 K, Tb (green) at 590 K and Tm (blue) at 530 K, respectively. For Tb- and Tm-doped AlN samples, temperature-dependent crossrelaxation processes were observed. Photoluminescence excitation spectra, obtained under UV excitation in the spectral range 200,400 nm, exhibit several bands. It is proposed that the RE ions exist in semiconductors as isolated ions (singlet), nearest-neighbor (nn) ion pairs (dimer), and three ions (trimer). The Koster,Slater and simple spherical potential-well models for RE-structured isovalent (RESI) hole trap are proposed. The exciton binding energies of RESI traps are calculated and compared with experimental thermal-quenching energies. The energy-transfer processes between the AlN host and the 4f-shell systems are emphasized as the main mechanisms for thermal-quenching processes rather than nonradiative decay of 4f transitions. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||