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51.
Some chemical and physical properties of extracellular polysaccharides produced by Butyrivibrio fibrisolvens strains. 下载免费PDF全文
Most strains of Butyrivibrio fibrisolvens are known to produce extracellular polysaccharides (EPs). However, the rheological and functional properties of these EPs have not been determined. Initially, 26 strains of Butyrivibrio were screened for EP yield and apparent viscosities of cell-free supernatants. Yields ranged from less than 1.0 to 16.3 mg per 100 mg of glucose added to the culture. Viscosities ranged from 0.71 to 5.44 mPa.s. Five strains (CF2d, CF3, CF3a, CE51, and H10b) were chosen for further screening. The apparent viscosity of the EP from each of these strains decreased by only 50 to 60% when the shear rate was increased from 20 to 1,000 s-1. Strain CE51 produced the EP having the highest solution viscosity. A detailed comparison of shear dependency of the EP from strain CF3 with xanthan gum showed that this EP was less shear sensitive than xanthan gum and, at a shear rate of 1,000 s-1, more viscous. EPs from strains CF3 and H10b were soluble over a wide range of pH (1 to 13) in 80% (vol/vol) ethanol-water or in 1% (wt/vol) salt solutions. The pH of 1% EP solutions was between 4.5 and 5.5. Addition of acid increased solution viscosities, whereas addition of base decreased viscosity. EPs from strains CF3, CE51, and H10b displayed qualitatively similar infrared spectra. Calcium and sodium were the most abundant minerals in the three EPs. The amounts of magnesium, calcium, and iron varied considerably among the EPs, but the potassium contents remained relatively constant. 相似文献
52.
Cecilie?M?MejdellEmail author Grete?HM?J?rgensen Therese?Rehn Kjersti?Fremstad Linda?Keeling Knut?E?B?e 《Acta veterinaria Scandinavica》2010,52(1):68
Background
The risk of injuries is of major concern when keeping horses in groups and there is a need for a system to record external injuries in a standardised and simple way. The objective of this study, therefore, was to develop and validate a system for injury recording in horses and to test its reliability and feasibility under field conditions.Methods
Injuries were classified into five categories according to severity. The scoring system was tested for intra- and inter-observer agreement as well as agreement with a 'golden standard' (diagnosis established by a veterinarian). The scoring was done by 43 agricultural students who classified 40 photographs presented to them twice in a random order, 10 days apart. Attribute agreement analysis was performed using Kendall's coefficient of concordance (Kendall's W), Kendall's correlation coefficient (Kendall's τ) and Fleiss' kappa. The system was also tested on a sample of 100 horses kept in groups where injury location was recorded as well.Results
Intra-observer agreement showed Kendall's W ranging from 0.94 to 0.99 and 86% of observers had kappa values above 0.66 (substantial agreement). Inter-observer agreement had an overall Kendall's W of 0.91 and the mean kappa value was 0.59 (moderate). Agreement for all observers versus the 'golden standard' had Kendall's τ of 0.88 and the mean kappa value was 0.66 (substantial). The system was easy to use for trained persons under field conditions. Injuries of the more serious categories were not found in the field trial.Conclusion
The proposed injury scoring system is easy to learn and use also for people without a veterinary education, it shows high reliability, and it is clinically useful. The injury scoring system could be a valuable tool in future clinical and epidemiological studies.53.
Sylvia Kamphuis Kolbrún Hrafnkelsdóttir Mark R Klein Wilco de Jager Margje H Haverkamp Jolanda HM van Bilsen Salvatore Albani Wietse Kuis Marca HM Wauben Berent J Prakken 《Arthritis research & therapy》2007,8(6):R178
Juvenile idiopathic arthritis (JIA) is a heterogeneous autoimmune disease characterized by chronic joint inflammation. Knowing
which antigens drive the autoreactive T-cell response in JIA is crucial for the understanding of disease pathogenesis and
additionally may provide targets for antigen-specific immune therapy. In this study, we tested 9 self-peptides derived from
joint-related autoantigens for T-cell recognition (T-cell proliferative responses and cytokine production) in 36 JIA patients
and 15 healthy controls. Positive T-cell proliferative responses (stimulation index ≥2) to one or more peptides were detected
in peripheral blood mononuclear cells (PBMC) of 69% of JIA patients irrespective of major histocompatibility complex (MHC)
genotype. The peptides derived from aggrecan, fibrillin, and matrix metalloproteinase (MMP)-3 yielded the highest frequency
of T-cell proliferative responses in JIA patients. In both the oligoarticular and polyarticular subtypes of JIA, the aggrecan
peptide induced T-cell proliferative responses that were inversely related with disease duration. The fibrillin peptide, to
our knowledge, is the first identified autoantigen that is primarily recognized in polyarticular JIA patients. Finally, the
epitope derived from MMP-3 elicited immune responses in both subtypes of JIA and in healthy controls. Cytokine production
in short-term peptide-specific T-cell lines revealed production of interferon-γ (aggrecan/MMP-3) and interleukin (IL)-17 (aggrecan)
and inhibition of IL-10 production (aggrecan). Here, we have identified a triplet of self-epitopes, each with distinct patterns
of T-cell recognition in JIA patients. Additional experiments need to be performed to explore their qualities and role in
disease pathogenesis in further detail. 相似文献
54.
Saturation and comparative mapping of a major Fusarium head blight resistance QTL in tetraploid wheat 总被引:2,自引:0,他引:2
Xunfen Chen Justin D. Faris Jinguo Hu Robert W. Stack Tika Adhikari Elias M. Elias Shahryar F. Kianian Xiwen Cai 《Molecular breeding : new strategies in plant improvement》2007,19(2):113-124
Fusarium head blight (FHB) is a devastating disease of cultivated wheat worldwide. Partial resistance to FHB has been identified
in common wheat (Triticum aestivum L.). However, sources of effective FHB resistance have not been found in durum wheat (T. turgidum L. var. durum). A major FHB resistance quantitative trait loci (QTL), Qfhs.ndsu-3AS, was identified on chromosome 3A of T.
dicoccoides, a wild relative of durum wheat. Here, we saturated the genomic region containing the QTL using EST-derived target region
amplified polymorphism (TRAP), sequence tagged site (STS), and simple sequence repeat (SSR) markers. A total of 45 new molecular
marker loci were detected on chromosome 3A and the resulting linkage map consisted of 55 markers spanning a genetic distance
of 277.2 cM. Qfhs.ndsu-3AS was positioned within a chromosomal interval of 11.5 cM and is flanked by the TRAP marker loci, Xfcp401 and Xfcp397.2. The average map distance between the marker loci within this QTL region was reduced from 4.9 cM in the previous study to
3.5 cM in the present study. Comparative mapping indicated that Qfhs.ndsu-3AS is not homoeologous to Qfhs.ndsu-3BS, a major FHB QTL derived from the common wheat cultivar Sumai 3. These results facilitate our efforts toward map-based cloning
of Qfhs.ndsu-3AS and utilization of this QTL in durum wheat breeding via marker-assisted selection. 相似文献
55.
T N Young J M Edelberg S Stack S V Pizzo 《Archives of biochemistry and biophysics》1992,296(2):530-538
Ionic strength, divalent cations, and Cl- modulate the ability of the glycosaminoglycan heparin to stimulate the activation of human plasminogen (Pg) by tissue-type Pg activator. Kinetic analysis of Pg activation indicates that heparin is inhibitory, stimulatory, or nonstimulatory as a function of ionic strength. While increasing ionic strength inhibits Pg activation in the absence of heparin, in it presence an activation phase followed by an inhibitory phase is observed. Divalent cations, inhibitors of activation in the absence of heparin, increase the rate of activation in its presence. Kinetic analysis demonstrates that divalent cations augment the heparin stimulatory effect a maximum of 60-fold due to increases in kcat without changes in Km of the reaction. This effect is heparin-specific, since activation is not affected by Ca2+ in the presence of heparan sulfate or de-N-sulfated heparin. Also, Cl- inhibits Pg activation in the presence of heparin by acting as a competitive inhibitor (Kic of 100 mM). Furthermore, inhibition by Cl- reduces the overall magnitude of heparin stimulation of Pg activation. These results suggest that physiologic ions in combination with heparin may be significant effectors of Pg activation in the vascular microenvironment. 相似文献
56.
Recent studies have suggested a close association between total respiratory compliance (Crs) and tidal volume in anesthetized paralyzed infants who are being artificially ventilated. To investigate this further, the multiple occlusion technique was used to measure Crs in 20 anesthetized infants and young children (aged 1-25 mo) before elective surgery. Measurements were made after intubation 1) during spontaneous breathing (SB), 2) after administration of a non-depolarizing muscle relaxant with tidal volume and frequency mimicking that during SB, and 3) with the child still paralyzed but tidal volume approximately double that during SB. Compared with values obtained during SB, there was no significant change in Crs after paralysis when ventilation matched the child's own pattern (P greater than 0.2). When ventilated with the larger tidal volumes, the infants showed a highly significant increase in Crs (mean 62%, range 14-158%, P less than 0.0001). These results may have implications not only for studies performed during anesthesia but also when infants were monitored in the intensive care setting. Values of Crs obtained in ventilated infants may reflect both the mechanical behavior of the respiratory system and the pattern of ventilation at the time of measurement. 相似文献
57.
58.
Bioinspired copper-model-complexes that react with O(2) provide an opportunity to probe biological reactivity at a small-molecule level of detail. Biological structural information combined with appropriate ligand design has proven sufficient to create Cu:O(2) complexes capable of external substrate oxidation. Most notable developments during the review period are the bioinspired catalysts capable of aerobic alcohol-oxidation. The extension of this oxidative reactivity to other important organic transformations beyond the scope of the inspiring system completes a modeling paradigm. 相似文献
59.
Thirty-five deer mice, Peromyscus maniculatus, were trapped on Gannet Cluster 2 (GC-2), one of a group of islands numbered by convention in the Gannet Island Archipelago, and examined for ectoparasites. One species each of Acari (Ixodes uriae) and Siphonaptera (Orchopeas leucopus) were recovered. Samples of mice favored males to females (3.4∶1). Twenty-nine percent (10) of the mice were free of ectoparasites. Males were more heavily parasitized than females when both parasites were considered. No ticks were recovered from the female mice, while the males that were parasitized carried adult Ixodes uriae. These 2 ectoparasites parasitizing P. maniculatus, which is a known reservoir host for Lyme disease (Borrelia burgdorferi), may carry B. garinii and their presence would have serious implications for the spread of this human pathogen northward in continental North America. 相似文献
60.
Hanna W van Steenbergen Jessica AB van Nies Tom WJ Huizinga Monique Reijnierse Annette HM van der Helm-van Mil 《Arthritis research & therapy》2014,16(2):R92