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91.
Kocharova NA Ovchinnikova OG Torzewska A Shashkov AS Knirel YA Rozalski A 《Carbohydrate research》2007,342(3-4):665-670
An oligosaccharide that corresponds to the repeating unit of the O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O36. Structural studies of the oligosaccharide and O-deacylated lipopolysaccharide were performed using sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, and H-detected (1)H,(13)C HSQC and HMBC experiments. It was found that the O-polysaccharide is built up of linear trisaccharide repeating units containing 2-acetamido-2-deoxyglucose, 6-deoxy-l-talose (l-6dTal), and 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and has the following structure. [structure: see text] 相似文献
92.
MicroRNA-451 Regulates LKB1/AMPK Signaling and Allows Adaptation to Metabolic Stress in Glioma Cells
93.
Małgorzata Giel-Pietraszuk Agnieszka Fedoruk-Wyszomirska Jan Barciszewski 《Molecular biology reports》2010,37(8):3713-3719
Formation and stabilization of RNA structure in the cell depends on its interaction with solvent and metal ions. High hydrostatic pressure (HHP) is a convenient tool in an analysis of the role of small molecules in the structure stabilization of biological macromolecules. Analysis of HHP effect and various concentrations of ions showed that water induce formation of the active ribozyme structure. So, it is clear that water is the driving force of conformational changes of nucleic acid. 相似文献
94.
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96.
From macro to lab-scale: Changes in bacterial community led to deterioration of EBPR in lab reactor 总被引:1,自引:0,他引:1
Adam Muszy��ski Maria ?ebkowska Agnieszka Tabernacka Aleksandra Mi?ob?dzka 《Central European Journal of Biology》2013,8(2):130-142
A laboratory scale sequencing batch reactor (SBR), fed with synthetic wastewater containing a mixture of organic compounds, was operated for nearly six months. Despite maintaining the same operational conditions, a deterioration of enhanced biological phosphorus removal (EBPR) occurred after 40 days of SBR operation. The Prel/Cupt ratio decreased from 0.28 to 0.06 P-mol C-mol?1, and C requirements increased from 11 to 32 mg C h?1 g?1 of mixed liquor suspended solids. A FISH analysis showed that the percentage of Accumulibacter in an overall community of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) dropped from 93% to 13%. An increase in abundance of Gammaproteobacteria (from 2.6% to 22%) and Alphaproteobacteria (from 1.8% to 10%) was observed. The number of Competibacter increased from 0.5% to nearly 9%. Clusters 1 and 2 of Defluviicoccus-related GAOs, not detected before deterioration, constituted 35% and 27% of Alphaproteobacteria, respectively. We concluded that lab-scale experiments should not be extended implicitly to full-scale EBPR systems because some bacterial groups are detected mainlyin lab-scale reactors. Well-defined, lab-scale operational conditions reduce the number of ecological niches available to bacteria. 相似文献
97.
Justyna Guzy-Wrobelska Maria Filek Agnieszka Kaliciak Iwona Szarejko Ivana Macháčková Jan Krekule Mirosława Barciszewska 《Acta Physiologiae Plantarum》2013,35(3):817-827
Vernalization-induced flowering is an effect of the epigenetic regulation of gene expression through DNA methylation and histone modifications. Vernalization-mediated silencing of a floral repressor through histone modifications was shown in Arabidopsis thaliana. However, for Brassica napus L., the mechanism underlying vernalization is unclear, and the roles of DNA methylation and histone modifications have not been established. This study revealed the profiles of changes in the DNA methylation state during vernalization (after 14, 35, 56 days) and the subsequent growth in long- or short-day photoperiods (after 2, 7, 14 days) in the winter and spring rapeseed using TLC and MSAP techniques. TLC analysis showed a significant decrease in the amount of 5-methylcytosine (m5C) in genomic DNA in both cultivars at the beginning of vernalization, but upon its termination, the winter rape showed a reduced level of m5C contrary to a significantly increased level in the spring rape. MSAP analysis revealed that winter and spring rapeseed differed in the MSAP loci which were demethylated/methylated in the course of the experiment and presented diverse profiles of changes in the methylation state. The winter rape showed permanent demethylations at 69.2 % of MSAP loci in the course of vernalization that were mostly preserved upon its termination. The spring rape showed similar numbers of demethylations and methylations that were mainly transient. The study provides evidence of the role of DNA methylation in vernalization for rapeseed and for the significant prevalence of demethylations at the beginning of vernalization, which is necessary for the transition to reproductive growth. 相似文献
98.
99.
Gaucher disease is a lysosomal storage disorder caused by deficiency of human acid β-glucosidase. Recent x-ray structural
elucidation of the enzyme alone and in the presence of its inhibitor was done, which provided an excellent template for further
studies on the binding of substrate, product and inhibitor. To draw correlations between the clinical manifestation of the
disease driven by point mutations, L444P and L444R, and the placement and function of putative S-binding sites, the presented
theoretical studies were undertaken, which comprised of molecular dynamics and molecular docking methods. The obtained results
indicate the D443 and D445 residues as extremely important for physiological functionality of an enzyme. They also show, although
indirectly, that binding of the substrate is influenced by an interplay of E235 and E334 residues, constituting putative substrate
binding site, and the region flanked by D435 and D445 residues.
Figure The binding of an arbitrarily chosen structure of glucosylceramide (A), conduritol-β-epoxide (B), glucose (C) to the active
site D443/D445 (A1, B1, C1) and E320/E340 (A2, B2, C2) of the wild-type structure of human acid-β-glucosidase. A1, B1, C1
blue mask represents the residues D443-D445; red mask represents the residue D444; A2, B2, C2 blue mask represents loop1 (Ser345-Glu349) and loop2 (Val394-Asp399), whereas red mask the residues E235 and 340 相似文献
100.
Gabriela Bugla-Płoskońska Jacek Rybka Bożena Futoma-Kołoch Agnieszka Cisowska Andrzej Gamian Włodzimierz Doroszkiewicz 《Microbial ecology》2010,59(3):601-613
Sialic acid (N-acetylneuraminic acid, NeuAc) plays an essential role in protecting gram-negative bacteria against the bactericidal
activity of serum and may contribute to the pathogenicity of bacteria by mimicking epitopes that resemble host tissue components
(molecular mimicry). The role of sialic acid (NeuAc)-containing lipopolysaccharides (LPS) of Salmonella O48 strains in the complement activation of normal human serum (NHS) was investigated. NeuAc-containing lipooligosaccharides
cause a downregulation of complement activation and may serve to camouflage the bacterial surface from the immunological response
of the host. Serotype O48 Salmonella strains have the O-antigen structure containing NeuAc while its serovars differ in outer membrane protein composition. In
this study, the mechanisms of complement activation responsible for killing Salmonella O48 serum-sensitive rods by NHS were established. Four of such mechanisms involving pathways, which are important in the
bactericidal mechanism of complement activation, were distinguished: only the classical/lectin pathways, independent activation
of the classical/lectin or alternative pathway, parallel activation of the classical/lectin and alternative pathways, and
only the alternative pathway important in the bactericidal action of human serum. To further study the role of NeuAc, its
content in bacterial cells was determined by gas-liquid chromatography-mass spectrometry in relation to 3-deoxy-D-manno-2-octulosonic
acid (Kdo), an inherent constituent of LPS. The results indicate that neither the presence of sialic acid in LPS nor the length
of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal
activity of complement and that the presence of sialic acid in the structure of LPS is not sufficient to block the activation
of the alternative pathway of complement. We observed that for three strains with a very high NeuAc/Kdo ratio the alternative
pathways were decisive in the bactericidal action of human serum. The results indicated that those strains are not capable
of inhibiting the alternative pathway very effectively. As the pathogenicity of most Salmonella serotypes remains undefined, research into the interactions between these bacterial cells and host organisms is indispensable. 相似文献