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171.
Schwaiger FW; Weyers E; Buitkamp J; Ede AJ; Crawford A; Epplen JT 《Molecular biology and evolution》1994,11(2):239-249
Exon 2 sequences of an expressed MHC-DRB locus from sheep were examined for
polymorphisms in both the antigen-binding regions and the adjacent intronic
mixed simple tandem repeat. Twenty-one novel exon 2 Ovar-DRB alleles were
identified. Short nucleotide motifs are extensively shared between certain
exon 2 regions of Ovar-DRB alleles. The simple repeat variations, the
number of different amino acids at usually polymorphic sites, and the
number of silent substitutions were reduced in the intraspecies analyses of
sheep DRB sequences, compared with those of cattle and goats. It was
paradoxical that the abundance of different sheep alleles was similar to
that of cattle and goats. This paradox may be explained by postulating a
relatively small number of "ancient" alleles, with the present-day Ovar-DRB
alleles being generated by reciprocal exchange of nucleotide motifs. At the
antigen-binding sites, new combinations of amino acids were maintained in
Ovar-DRB alleles by strong positive selection. In sheep--and less
pronounced in goats and cattle--the DRB alleles can be divided into two
groups. In one group, silent substitutions are increased when compared with
the other. This suggests separate evolutionary pathways for certain groups
of DRB alleles within a species. The simple repetitive sequences are also
discussed with respect to the evolution of DRB alleles.
相似文献
172.
Robert A Clayton Colin AJ Dick Alison Mackenzie Michiaki Nagasawa Deirdre Galbraith Stuart F Hastings Simon J MacKenzie 《Respiratory research》2004,5(1):4
BackgroundThe anti-inflammatory effects of the selective phosphodiesterase (PDE) inhibitors cilostazol (PDE 3), RO 20-1724 (PDE 4) and sildenafil (PDE 5) were examined in a murine model of allergic asthma. These compounds were used alone and in combination to determine any potential synergism, with dexamethasone included as a positive control.MethodsControl and ovalbumin sensitised Balb/C mice were administered orally with each of the possible combinations of drugs at a dose of 3 mg/Kg for 10 days.ResultsWhen used alone, RO 20-1724 significantly reduced eosinophil influx into lungs and lowered tumour necrosis factor-α, interleukin-4 and interleukin-5 levels in the bronchoalveolar lavage fluid when compared to untreated mice. Treatment with cilostazol or sildenafil did not significantly inhibit any markers of inflammation measured. Combining any of these PDE inhibitors produced no additive or synergistic effects. Indeed, the anti-inflammatory effects of RO 20-1724 were attenuated by co-administration of either cilostazol or sildenafil.ConclusionsThese results suggest that concurrent treatment with a PDE 3 and/or PDE 5 inhibitor will reduce the anti-inflammatory effectiveness of a PDE 4 inhibitor. 相似文献
173.
Antony PB Black Hansha Bhayani Clive AJ Ryder Janet MM Gardner-Medwin Taunton R Southwood 《Arthritis research & therapy》2001,4(3):177
A study was done to determine if the differentiation and activation phenotype of T cells in synovial fluid (SF) from patients with juvenile idiopathic arthritis (JIA) is associated with T-cell proliferation in situ. Mononuclear cells were isolated from 44 paired samples of peripheral blood and SF. Differentiation and activation markers were determined on CD4 and CD8 T cells by flow cytometry. Cell-cycle analysis was performed by propidium iodide staining, and surface-marker expression was also assessed after culture of the T cells under conditions similar to those found in the synovial compartment. The majority of the T cells in the SF were CD45RO+CD45RBdull. There was greater expression of the activation markers CD69, HLA-DR, CD25 and CD71 on T cells from SF than on those from peripheral blood. Actively dividing cells accounted for less than 1% of the total T-cell population in SF. The presence or absence of IL-16 in T-cell cultures with SF or in a hypoxic environment did not affect the expression of markers of T-cell activation. T cells from the SF of patients with JIA were highly differentiated and expressed early and late markers of activation with little evidence of in situ proliferation. This observation refines and extends previous reports of the SF T-cell phenotype in JIA and may have important implications for our understanding of chronic inflammation. 相似文献
174.
Aguilera M Quesada MT Del Aguila VG Morillo JA Rivadeneyra MA Ramos-Cormenzana A Monteoliva-Sánchez M 《Bioresource technology》2008,99(13):5640-5644
A total of 10 bacterial strains were isolated from a compost of corn treated with olive mill wastewaters (OMW) and selected by their capacity to synthesize exopolysaccharides (EPS). Morphological, physiological, biochemical and nutritional tests were used for a phenotypic study. A numerical analysis showed that all strains were 90% similar to each other. A DNA–DNA hybridization assay confirmed that all the strains belonged to Paenibacillus jamilae species. All the characterized strains were able to produce EPS growing on OMW batch cultures. The strain which was able to produce the highest EPS yield was chosen to perform an assay for testing its putative detoxifying activity, and it showed to reduce more than half the toxic capacity of the OMW. The results presented in this study, indicated the possible perspectives for using these bacterial strains to produce EPS and contribute to the bioremediation of the waste waters that are produced in the olive oil elaboration process. 相似文献
175.
Morillo JA Aguilera M Antízar-Ladislao B Fuentes S Ramos-Cormenzana A Russell NJ Monteoliva-Sánchez M 《Applied microbiology and biotechnology》2008,79(2):309-317
Two-phase olive mill waste (TPOMW) is a semi-solid effluent that is rich in contaminating polyphenols and is produced in large
amounts by the industry of olive oil production. Laboratory-scale bioreactors were used to investigate the biodegradation
of TPOMW by its indigenous microbiota. The effect of nutrient addition (inorganic N and P) and aeration of the bioreactors
was studied. Microbial changes were investigated by PCR-temperature time gradient electrophoresis (TTGE) and following the
dynamics of polar lipid fatty acids (PLFA). The greatest decrease in the polyphenolic and organic matter contents of bioreactors
was concomitant with an increase in the PLFA fungal/bacterial ratio. Amplicon sequences of nuclear ribosomal internal transcribed
spacer region (ITS) and16S rDNA allowed identification of fungal and bacterial types, respectively, by comparative DNA sequence
analyses. Predominant fungi identified included members of the genera Penicillium, Candida, Geotrichum, Pichia, Cladosporium, and Aschochyta. A total of 14 bacterial genera were detected, with a dominance of organisms that have previously been associated with plant
material. Overall, this work highlights that indigenous microbiota within the bioreactors through stimulation of the fungal
fraction, is able to degrade the polyphenolic content without the inoculation of specific microorganisms. 相似文献
176.
177.
178.
ABSTRACT: Co-evolving positions within protein sequences have been used as spatial constraints to develop a computational approach for modeling membrane protein structures. 相似文献
179.
The knowledge of the host-guest complexes using cyclodextrins (CDs) has prompted an increase in the development of new formulations. The capacity of these organic host structures of including guest within their hydrophobic cavities, improves physicochemical properties of the guest. In the case of pesticides, several inclusion complexes with cyclodextrins have been reported. However, in order to explore rationally new pesticide formulations, it is essential to know the effect of cyclodextrins on the properties of guest molecules.In this study, the inclusion complexes of bentazon (Btz) with native βCD and two derivatives, 2-hydroxypropyl-β-cyclodextrin (HPCD) and sulfobutylether-β-cyclodextrin (SBECD), were prepared by two methods: kneading and freeze-drying, and their characterization was investigated with different analytical techniques including Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), X-ray diffractometry (XRD) and differential pulse voltammetry (DPV). All these approaches indicate that Btz forms inclusion complexes with CDs in solution and in solid state, with a stoichiometry of 1∶1, although some of them are obtained in mixtures with free Btz. The calculated association constant of the Btz/HPCD complex by DPV was 244±19 M(-1) being an intermediate value compared with those obtained with βCD and SBECD. The use of CDs significantly increases Btz photostability, and depending on the CDs, decreases the surface tension. The results indicated that bentazon forms inclusion complexes with CDs showing improved physicochemical properties compared to free bentazon indicating that CDs may serve as excipient in herbicide formulations. 相似文献
180.
Macías García B Ortega Ferrusola C Aparicio IM Miró-Morán A Morillo Rodriguez A Gallardo Bolaños JM González Fernández L Balao da Silva CM Rodríguez Martínez H Tapia JA Peña FJ 《Theriogenology》2012,77(7):1280-1289
Glycerol is, to date, the most widely used cryoprotectant to freeze stallion spermatozoa at concentrations between 2% and 5%. Cryoprotectant toxicity has been claimed to be the single most limiting factor for the success of cryopreservation. In order to evaluate the toxic effects of the concentrations of glycerol used in practice, stallion spermatozoa were incubated in Biggers Whitten and Whittingham (BWW) media supplemented with 0%, 0.5%, 1.5%, 2.5%, 3.5%, and 5% glycerol. In two additional experiments, a hyposmotic (75 mOsm/kg) and a hyperosmotic (900 mOsm/kg) control media were included. Sperm parameters evaluated included cell volume, membrane integrity, lipid peroxidation, caspase 3, 7, and 8 activation, mitochondrial membrane potential, and integrity of the cytoskeleton. Glycerol exerted toxicity at concentrations ≥ 3.5% and the maximal toxicity was observed at 5%. The actin cytoskeleton was especially sensitive to glycerol presence, inducing rapid F actin depolymerization at concentrations over 1.5%. The sperm membrane and the mitochondria were other structures affected. The toxicity of glycerol is apparently related to osmotic and nonosmotic effects. In view of our results the concentration of glycerol in the freezing media for stallion spermatozoa should not surpass 2.5%. 相似文献