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101.
Identification and characterization of vaccinia virus genes encoding proteins that are highly antigenic in animals and are immunodominant in vaccinated humans.
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Vaccinia virus (VV) is a potent immunogen, but the nature of VV proteins involved in the activation of the immune response of the host is not yet known. By screening a lambda gt11 expression library of rabbitpox virus DNA with serum from humans vaccinated against smallpox or with serum from VV-immunized animals, we identified several VV genes that encode highly antigenic viral proteins with molecular masses of 62, 39, 32, 25, 21, and 14 kDa. It was found that VV proteins of 62, 39, 25, and 21 kDa are part of the virus core, while proteins of 32 and 14 kDa are part of the virus envelope. All of these proteins were synthesized at late times postinfection. Proteins of 62 and 25 kDa were produced by cleavage of larger precursors of 95 kDa (p4a) and 28 kDa, respectively. The 21-kDa protein was the result of a cleavage of p4a, presumably at amino acid Gly-697. DNA sequence analysis, in comparison with the known nucleotide sequence of VV, provided identification of the corresponding open reading frames. Expression of the viral genes in Escherichia coli was used to monitor which of the viral antigens elicit immunodominant responses and the location of antigenic domains. Three viral antigens of 62, 39, and 32 kDa exhibited immunodominant characteristics. The most antigenic sites of 62 and 39 kDa were identified at the N terminus (amino acids 132 to 295) and C terminus (last 103 amino acids), respectively. Immunization of mice with the 62-, 39-, or 14-kDa antigenic proteins conferred different degrees of protection from VV challenge. Proteins of 32 and 14 kDa induced cellular proliferative responses in VV-infected mice. Our findings demonstrate the nature of VV proteins involved in the activation of host immune responses after vaccination, provide identification of the viral gene locus, and define structural and immunological properties of these antigenic VV proteins. 相似文献
102.
Pierangelo Luporini Cristina Miceli Claudio Ortenzi Adriana Vallesi 《Genesis (New York, N.Y. : 2000)》1992,13(1):9-15
Euplotes raikovi, like other ciliates, passes through a postconjugal immaturity, operatively identified by an apparent cell inability to form mating pairs under experimental conditions that are the same as those used for inducing mating at maturity. In cells homozygous for the gene mat-2, which controls the pheromone Er-2, Er-2 mRNA synthesis and mature Er-2 secretion were shown to start from the very beginning of the life cycle and continue throughout immaturity, although to extents estimated to be 5- to 10-fold lower than at maturity. In addition, experiments of 125 I-Er-2 binding and crosslinking provided evidence that autocrine pheromone-binding sites, showing values of the dissociation constant of the order of 10?9 M, are on the surface of immature cells. The number of these sites per cell was estimated to increase from less than 106 per cell of 5–7 fissions of age, to about 16 × 106 at maturity. These results were taken to suggest that a pheromone-receptor production is stimulated during immaturity by autocrine pheromone binding to cells and that this production might be essential for the development of a pheromone-receptor density high enough to transform the cell from “immature” to “adult,” that is competent to respond as well to pheromones of conspecific, genetically different cells. © 1992 Wiley-Liss, Inc. 相似文献
103.
The effects of ovariectomy and administration of estradiol on the activity of liver alcohol dehydrogenase and on the rate of ethanol elimination were determined in female Sprague-Dawley rats. The activity of the enzyme and the rates of ethanol elimination in the female sham-operated animals were higher than obtained previously in male rats of the same age. Ovariectomy had no effect on liver alcohol dehydrogenase and on rates of ethanol elimination. Estradiol administration resulted in an increase in liver weight and in total liver alcohol dehydrogenase activity per animal in sham-operated but not in ovariectomized animals. The increase in enzyme activity after estradiol administration in sham-operated animals was not associated with a significant increase in the rate of ethanol elimination, suggesting that the enzyme activity in female rats is not rate-limiting in in vivo ethanol oxidation. 相似文献
104.
NAD-linked lactate, malate, glycerophosphate, alcohol and nonspecific dehydrogenases, aspartate aminotransferases, and soluble esterases from extracts of tissues of individuals from a wild population of Calomys musculinus (Rodentia, Cricetidae) have been analyzed by means of starch gel electrophoresis and specific staining. Allelic frequencies and heterozygosity have been determined. Mendelian inheritance of some of the variants detected was confirmed by breeding experiments. Ten out of fifteen (66.6%) of the genetic loci investigated presented polymorphism. Mean heterozygosity per locus was very high (H=0.2014, se 0.046).This work has been supported, in part, by grants from the Secretaria de Ciencia y Tecnología de la Nación (National Program for Endemic Diseases) and from the Fundación Emilio Ocampo. C. N. G. is a Fellow and A. B. a Career Investigator of the Consejo Nacional de Investigaciones Científicas y Técnicas of Argentina. 相似文献
105.
M. Cristina García Kirkbride 《Brittonia》1979,31(3):313-332
All neotropical genera previously included in the tribe Isertieae A. Rich. ex DC. are considered. The tribe Isertieae is here delimited by the following characters: absence of rhaphides, valvate aestivation of the corolla, cordiform or discoid placenta, fleshy indehiscent fruit, and seed coat cells with pitted walls. As so delimited, the tribe definitely includes the neotropical generaIsertia Schreb.,Gonzalagunia Ruiz & Pav.,Amphidasya Standl.,Raritebe Wernh.,Sabicea Aubl., andMussaenda L. as well as some paleotropical genera not here considered. The following neotropical genera are excluded from tribe Isertieae:Hippotis Ruiz & Pav.,Pentagonia Benth.,Sommera Schlecht.,Tammsia Karst.,Coccocypselum P. Browne,Schradera Vahl,Didymochlamys Hook, f., andXerococcus Oerst. The position of four genera,Striolaria Ducke,Patima Aubl.,Habroneuron Standl., andNeosabicea Wernh., remains uncertain due to a lack of material. 相似文献
106.
Chromosome polymorphism in populations of the grasshopper Trimerotropis pallidipennis from southern Argentina 总被引:1,自引:0,他引:1
Three populations of the grasshopper Trimerotropis pallidipennis from southern Argentina have been studied cytologically. A very characteristic B-chromosome was found in all three. They also showed geographical variability in respect of the presence of pericentric inversions, and the inversion system was found to influence chiasma frequency. The Laguna Blanca population, which is on the hypothetical pathway the species is believed to have followed during its migration from northern to southern latitudes, has the same karyotype composition as the N. American form, with fixed inversions in the 3 largest autosomes and the X-chromosome. Its members have a high total chiasma frequency and a great number of interstitial chiasmata. The Sierra de la Ventana population, situated at the absolute eastern border of the species distribution is highly polymorphic with respect to the presence of inversions in the medium chromosomes. Its members have the lowest total chiasma frequency and a greatly reduced number of interstitial chiasmata. Situated geographically between the other two, the Choele-Choel population has the highest frequency of inversions and many of them are homozygous. Its members have a higher total chiasma frequency than that observed in specimens from Sierra de la Ventana, and a greatly reduced number of interstitial chiasmata, similar to that observed in individuals from the latter population. 相似文献
107.
M Poza M A Perez-Espejo J F Martinez-Lage J A Esteban V Climent J Sola 《Applied neurophysiology》1985,48(1-6):482-487
A modification of Gildenberg's technique for brain tumor biopsy is described. Marking the light beam of the gantry on the scalp with a pencil, when the lesion appears on the screen, no ScoutView is necessary. With radiopaque marks on the drawn lines, the levels of the slice are transferred to a lateral conventional X-ray, for calculation of the 'Z' coordinate. 'X' and 'Y' coordinates are determined on the CT scanner. 相似文献
108.
Elena Roura Ma Pilar Almajano Ma Lourdes Mata Bilbao Cristina Andrés-Lacueva Ramon Estruch 《Free radical research》2013,47(8):943-949
Associations between cocoa consumption in humans, excreted metabolites and total antioxidant capacity (TAC) have been scarcely investigated. The aims of the study were to investigate the epicatechin (( ? )-Ec) metabolites excreted in urine samples after an intake of 40 g of cocoa powder along with the TAC of these urine samples and the relation between both the analyses. Each of the 21 volunteers received two interventions, one with a polyphenol-rich food (PRF) and one with a polyphenol-free food (PFF) in a randomized cross-over study. Urine samples were taken before and during 24 h at 0–6, 6–12 and 12–24 h periods after test intake. The excreted ( ? )-Ec metabolites and the TAC were determined in urine samples by LC-MS/MS and TEAC assay, respectively. The maximum excretion of ( ? )-Ec metabolites and the maximum TAC value were observed in urine samples excreted between 6 and 12 h after PRF consumption. Significance of TAC increase was found in urine samples excreted during 0–6 and 6–12 h (66.6 and 72.67%, respectively, with respect to the 0 h). 相似文献
109.
110.
The species Proceratophrys cristiceps belongs to the genus Proceratophrys within the family Cycloramphidae. These amphibians are found exclusively in South America in the morphoclimatic domain of the semi-arid depression zones in northeastern Brazil known as the Caatinga. We examined intrapopulational variation using univariate and multivariate statistics with traditional and geometric morphometrics, which supported the existence of two morphotypes of this species. Our results indicated significant degrees of variation in skeletal characteristics between some natural populations of this species. Careful analyses of variability levels are fundamental to avoid taxonomic errors, principally in populations that demonstrate characteristics intimately associated with their area of occurrence, as is the case of Proceratophrys cristiceps. 相似文献