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51.

Background  

Heterologous prime-boost immunization protocols using different gene expression systems have proven to be successful tools in protecting against various diseases in experimental animal models. The main reason for using this approach is to exploit the ability of expression cassettes to prime or boost the immune system in different ways during vaccination procedures. The purpose of the project was to study the ability of recombinant vaccinia virus (VV) and bacterial plasmid, both carrying the NS1 gene from tick-borne encephalitis (TBE) virus under the control of different promoters, to protect mice against lethal challenge using a heterologous prime-boost vaccination protocol.  相似文献   
52.
Large-scale gene amplifications may have facilitated the evolution of morphological innovations that accompanied the origin of vertebrates. This hypothesis predicts that the genomes of extant jawless fish, scions of deeply branching vertebrate lineages, should bear a record of these events. Previous work suggests that nonvertebrate chordates have a single Hox cluster, but that gnathostome vertebrates have four or more Hox clusters. Did the duplication events that produced multiple vertebrate Hox clusters occur before or after the divergence of agnathan and gnathostome lineages? Can investigation of lamprey Hox clusters illuminate the origins of the four gnathostome Hox clusters? To approach these questions, we cloned and sequenced 13 Hox cluster genes from cDNA and genomic libraries in the lamprey, Petromyzon marinus. The results suggest that the lamprey has at least four Hox clusters and support the model that gnathostome Hox clusters arose by a two-round-no-cluster-loss mechanism, with tree topology [(AB)(CD)]. A three-round model, however, is not rigorously excluded by the data and, for this model, the tree topologies [(D(C(AB))] and [(C(D(AB))] are most parsimonious. Gene phylogenies suggest that at least one Hox cluster duplication occurred in the lamprey lineage after it diverged from the gnathostome lineage. The results argue against two or more rounds of duplication before the divergence of agnathan and gnathostome vertebrates. If Hox clusters were duplicated in whole-genome duplication events, then these data suggest that, at most, one whole genome duplication occurred before the evolution of vertebrate developmental innovations.  相似文献   
53.
A Amores  G Martinez  J Reina  M C Alvarez 《Génome》1993,36(4):672-675
A karyotype analysis was carried out in nine specimens of the Sparid species Diplodus bellottii using conventional staining, as well as C-banding and Ag-NOR banding techniques, showing, respectively, 2n = 46 and fundamental number (FN) = 54, and scarce heterochromatic areas irregularly distributed and up to four NOR active regions that were C positive. When compared with the karyotypes of other related species, one centric fusion giving rise to a large metacentric pair and several pericentric inversions seem to have been involved in the karyotype evolution. An intra-individual polymorphism was detected in one specimen, resulting in two karyotypic forms in roughly identical proportion, owing to a larger C-band by the NOR regions, appearing either in a terminal position of the short arms of pair 2 or in telomeric position of pair 3. These findings suggest that the extra heterochromatic segment responsible for the heteromorphism apparently only involves associated heterochromatin and not the NORs themselves. This C-positive block seems to have eventually been transferred between heterologous NOR chromosomes by a somatic event, facilitated by the physical proximity of NOR pairs in the nucleolus.  相似文献   
54.
The effects of various lipogenic and antilipogenic states on the activities of rat-kidney cortex glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase have been studied. These conditions are related to the long-term administration of different diets, such as high-carbohydrate (80%) and high-fat (23%), and also to a state of fast. Contrary to what happens in liver cells and kidney cortex during a high protein diet administration, none of these nutritional conditions produced significant changes in the kinetics of either kidney hexose monophosphate dehydrogenases.  相似文献   
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Angiogenesis, resulting from an imbalance between angiogenic activator factors and inhibitors, is required for tumour growth and metastasis. The determination of the circulating concentration of all angiogenic factors (activators and inhibitors) is not feasible at present. We have evaluated diagnostic and prognostic values of the measurement of serum angiogenic activity in colorectal carcinoma (CRC) patients. Serum proliferative activity (PA) on human umbilical vein endothelial cells (HUVEC) in vitro, and serum vascular endothelial growth factor (VEGF) levels were determined by ELISA in 53 patients with primary CRC, 16 subjects with non-neoplastic gastrointestinal disease (SC) and 34 healthy individuals. Data were compared with clinical outcome of the patients. Although serum from CRC patients significantly increased the PA of HUVEC, compared to culture control (HUVEC in medium + 10% foetal bovine serum (FBS); P < 0.001); our results indicate that serum PA in CRC patients was similar to that of SC or healthy individuals. There was no correlation between serum PA and circulating VEGF concentrations. Surgery produced a decrease of PA at 8 hrs after tumour resection in CRC patients compared to pre-surgery values (186 +/- 47 versus 213 +/- 41, P < 0.001). However, an increase in serum VEGF values was observed after surgery (280 [176-450] versus 251 [160-357] pg/ml, P = 0.004). Patients with lower PA values after surgery showed a worse outcome that those with higher PA values. Therefore, this study does not support a diagnostic value for serum angiogenic activity measured by proliferative activity on HUVEC but suggests it could have a prognostic value in CRC patients.  相似文献   
57.
Microbes that are beneficial to plants are used to enhance the crop growth, yield and are alternatives to chemical fertilizers. Trichoderma and Bacillus are the predominant plant growth-promoting fungi and bacteria. The objective of this study was select, characterize, and evaluate isolates of Trichoderma spp. and Bacillus spp. native from the northern region of Sinaloa, Mexico, and assess their effect on growth promotion in maize (Zea mays L.). In greenhouse conditions, four Trichoderma isolates and twenty Bacillus isolates, as well as two controls, were tested in a completely randomized design with three replicates. We selected the two best strains of Trichoderma and Bacillus: TB = Trichoderma asperellum, TF = Trichoderma virens, B14 = Bacillus cereus sensu lato and B17 = Bacillus cereus, which were evaluated in the field in a completely randomized blocks in factorial arrangement design with three replicates applying different rates of nitrogen fertilizer (0, 150 kg N/ha, and 300 kg N/ha). Treatments 5 (B17 = B. cereus) and 11 (TF = T. virens) both fertilized with 150 kg N/ha showed similar yields and they did not reveal significant differences from the treatments fertilized with 300 kg N/ha. This indicated that treatment 5 (B17= B. cereus with 150 kg N/ha) and treatment 11 (TF= T. virens with 150 kg N/ha) were efficient as growth promoters, by not showing significant differences in root volume and dry weight of foliage. The results indicated a reduction of 50% in the rate of nitrogen to fertilizer required for maize (Zea mays L.) crops. These microorganisms Trichoderma and Bacillus could be an alternative to reduce the use of chemical fertilizers in maize.  相似文献   
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59.
Secretory products of granular and mucous cells in the gill epithelium of the carp, Cyprinus carpio, were distinguished by their cytochemical reactions with peroxidase-labelled lectins and with the galactose oxidase (GO)-Schiff reagents. Secretory products of granular cells reacted with lectins from Triticum vulgaris (WGA), Arachis hypogaea (PNA), Dolichos biflorus (DBA), Glycine max (SAB), and Lotus tetragonolobus (LTA). They also reacted with GO-Schiff reagents. After sialic acid cleavage with HCl, new binding sites for DBA and SBA appeared, suggesting the terminal sequence sialic acid-N-acetylgalactosamine (SA-GalNAc) for the secretion of this cell type. In mucous cells, binding sites for WGA, DBA, and SBA and, after acid hydrolysis, binding sites for PNA and a positive GO-Schiff reaction were detected. The terminal trisaccharide sialic acid-galactose (beta 1-3)-N-acetylgalactosamine (SA-Gal-GalNAc) is proposed for the secretion of mucous cells. These cytochemical differences are discussed in light of the involvement of both cell types in fish mucus elaboration.  相似文献   
60.
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