The oligosaccharides from the lipopolysaccharides of
Moraxella catarrhalis serotype B, strain CCUG 3292, were isolated after mild acid hydrolysis and separated by high-performance anion-exchange ...chromatography. The structures of the oligosaccharides were established by fast atom bombardment mass spectrometry and nuclear magnetic resonance spectroscopy. It is concluded that the oligosaccharides comprise a mixture of mainly a nona- and a deca-saccharide.
▪ Smaller amounts of undecasaccharides and of truncated forms, namely, hexa-, hepta-, and octa-saccharides, were also detected.
Moraxella catarrhalis has recently been shown to be both widespread and pathogenic, in contrast to previous reports. Several factors have been suggested as virulence factors, lipopolysaccharide (LPS) ...being one. Recent studies have shown the LPS to be without the O‐chain, i.e. the polysaccharide part, and to have specific structural features corresponding to each of the three serogroups, A, B and C. The structures resemble in many respects those present in other Gram‐negative nonenteric bacteria, with a galabiosyl element as a prominent common denominator. The presence of such common structures suggests that the LPS of these bacteria might be a part of a mechanism of survival for bacteria colonizing the human host.
A highly hydrophobic protein with six transmembrane structure that is coded by the candidate tumor suppressor gene 101F6 located in the human chromosome 3p.21.3 and a possible member of the ...cytochrome b 561 protein family was expressed, purified, and characterized in its functional form for the first time. The protein was heterologously expressed in methylotrophic yeast Pichia pastoris as a fusion protein containing a C-terminal thrombin-specific sequence and an 8-His residue tag. Purification was achieved by ion exchange chromatography on DEAE-Sepharose and affinity chromatography on Ni-NTA-Sepharose. SDS-PAGE analysis revealed a single protein band with an estimated molecular weight of 26 kDa, while Western blot and MALDI-TOF-MS analysis confirmed the presence of the cytochrome b561 specific sequence in the protein. The 101F6 protein was found to be reducible by ascorbate efficiently and to have two midpoint potentials at +89.5 and +13.1 mV, slightly lower than the corresponding values of +155 and +62 mV, respectively, of bovine adrenal cytochrome b 561, despite a lower conservation of the putative ascorbate binding site sequence in the 101F6 protein. The "modified motif 1" sequence unique in 101F6 protein may be responsible for other molecular functions, such as protein-protein interactions, in the endoplasmic membranes.
Reservation of adequate food is a major concern for many developing countries worldwide. Governments of those countries also want to meet the demand of food in the long term, especially during the ...period of natural calamity. For low lying region such as Bangladesh, predicting the supply of food is critical. Besides, rice productivity of Bangladesh has also changed due to varying climatic over the last couple of decades. In this paper, a comprehensive analysis has been made to forecast the rice yield of Bangladesh.
A complete model is presented in this article for design optimization of hydraulic fracturing to enhance reservoir production. The model integrates reservoir properties, various design constraints to ...avoid induced formation damage, a hydraulically driven fracture geometry model, a hydrocarbon production model, and an economic model in deciding on the optimum values of various treatment parameters. The design constraints are intended to ensure that an optimum design obtained from the model can be executed in the field using the specified surface equipment and without causing uncontrolled fracture growth and/or initiation of multiple secondary fractures. A pseudo-3D fracture model is improved to establish better compatibility relationships between reservoir properties, treatment parameters, and fracture growth. Features of Genetic Algorithm and Evolutionary Operation are combined to develop a robust optimization algorithm that executes complex interactions between the above-mentioned modules to achieve an optimum design. The capability and robustness of the proposed model is demonstrated by applications to a tight-gas reservoir. By trade-off analysis between production/NPV and treatment cost, it is shown that only a 13% sacrifice of the maximum possible production/net present value (NPV) over ten years can save up to 52% of the fracturing treatment cost. Various other design issues are also investigated by sensitivity analyses.
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