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At least 703 records · Page 39Linked to original sources
PubMed2006

[Enhanced ammonia removal and microbial community structure analysis using bacterial quinone profile in ITFB].

Water quality during the start-up period was changed in order to enhance the later nitrifying ability of the internal-circulation three-phase bio-fluidized bed (ITFB). The experimental results showed that high N/C ratio and low feeding concentration of COD were two key conditions for enhancing the ammonia removal. After the enhanced start-up, an efficient removal efficiency of both COD and ammonia was achieved with HRT 2h when treating sanitary wastewater, the average ammonia removal rate was 74% , the ammonia concentration in effluent was lower than 10 mg/L. Bacterial quinone profile of the system was also analyzed. The results showed that after the enhanced start-up, the number of nitrifying bacteria, such as Nitrosomonas europaea, in the biofilm in ITFB was increased, and the number of gamma-Proteobacteria, such as Acinetobacter sp. and Pseudomonas sp., was decreased. the equitability of the quinones (EQ) fluctuated around 0.5 showed that the distribution of the microbial community in the biofilm changed little. UQ/MK ratio of all the samples was greater than 1 indicated that Gram-negative bacteria was the dominant bacteria in the system.

Ammonia↗
PubMed1986

Biosynthesis of bacterial glycogen. Primary structure of Escherichia coli ADP-glucose:alpha-1,4-glucan, 4-glucosyltransferase as deduced from the nucleotide sequence of the glgA gene.

The nucleotide sequence of the glgA gene, coding for glycogen synthase (EC 2.4.1.21) was elucidated. It consists of 1431 base pairs specifying a protein of 477 amino acids. The deduced amino acid sequence was consistent with the amino acid analysis obtained with the pure protein as well as with the molecular weight as determined from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The deduced amino acid sequence was also consistent with the amino-terminal acid sequence and amino acid sequence analysis of various peptides obtained from CNBr degradation of purified glycogen synthase.

Amino Acid Sequence↗
PubMed1987

Neutron scattering analysis of bacterial lipopolysaccharide phase structure. Changes at high pH.

The aggregate structure of lipopolysaccharide isolated from an Re strain of Escherichia coli was examined at different pH values using small angle neutron scattering. At pH values of 6 and 7.4, angle-averaged scattering of the sodium salt of this isolate was consistent with randomly coiled tubular micelles approximately 100 A in diameter. At pH 9.1, however, Kratky analysis of the scattering data was distinctly different and consistent with pairing of uniform tubular micelle sections of length 1440 and 110 A in diameter. Contrast variation measurements of the micelles yielded an average micellar weight of the sample at pH 9.1 of approximately 1.11 X 10(7) daltons and suggested that the aggregates were tubular micelles of size and length similar to that derived from the scattering intensity data. Anisotropic scattering patterns of samples under shear indicated a rigidification of the micelles as the pH was increased to 9.1 and the temperature decreased from 25 to 10 degrees C. The rotational diffusion constants deduced from the observed shear anisotropy indicate that the structure at pH 9.1 must have smallest and largest dimensions which differ by at least an order of magnitude, ruling out spherical or moderately ellipsoidal structures. Analysis of the shear rate needed to induce anisotropic scattering indicated that the stiffness length of the micelles at pH 9.1 was approximately 1000 A and decreased at higher and lower pH values.

Chemical Phenomena↗