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971.
ZAMORANO JOSE Unidad de Investigacion Hospital San Pedro de Alcantara Avda Millan Astray Caceres ANN E KELLY JONATHAN AUSTRIAN HELEN Y WANG ACHSAH D KEEGAN 《Cell research》2001,(1)
INTRODUCTIONThe inappropriate enhancement of lymphocytesurviVal due to a block in programmed cell deathand/or an enhancement of entry into the cell cyclecan contribute to the abnormal expansion of clonesresulting in tumorigenesis or the breakdown of pe-ripheral self-toleranced, 2]. Proper lymphocytehomeostasis is critical for normal immune functionand is maintained by a complex series of cellularinteractions and the action of secreted cytokines.Illterleukin-4 (IL-4), a cytokine produced … 相似文献
972.
Tomoaki Hishida Eric Vazquez-Ferrer Yuriko Hishida-Nozaki Ignacio Sancho-Martinez Yuta Takahashi Fumiyuki Hatanaka Jun Wu Alejandro Ocampo Pradeep Reddy Min-Zu Wu Laurie Gerken Reuben J. Shaw Concepcion Rodriguez Esteban Christopher Benner Hiroshi Nakagawa Pedro Guillen Garcia Estrella Nu ez Delicado Antoni Castells Josep M. Campistol Guang-Hui Liu Juan Carlos Izpisua Belmonte 《蛋白质与细胞》2019,10(7):485
Identification of the precise molecular pathways involved in oncogene-induced transformation may help us gain a better understanding of tumor initiation and promotion. Here, we demonstrate that SOX2+ foregut epithelial cells are prone to oncogenic transformation upon mutagenic insults, such as KrasG12D and p53 deletion. GFP-based lineage-tracing experiments indicate that SOX2+ cells are the cells-of-origin of esophagus and stomach hyperplasia. Our observations indicate distinct roles for oncogenic KRAS mutation and P53 deletion. p53 homozygous deletion is required for the acquisition of an invasive potential, and KrasG12D expression, but not p53 deletion, suffices for tumor formation. Global gene expression analysis reveals secreting factors upregulated in the hyperplasia induced by oncogenic KRAS and highlights a crucial role for the CXCR2 pathway in driving hyperplasia. Collectively, the array of genetic models presented here demonstrate that stratified epithelial cells are susceptible to oncogenic insults, which may lead to a better understanding of tumor initiation and aid in the design of new cancer therapeutics. 相似文献
973.
Ana Escrig Raquel Marin Pedro Abreu Jose Luis Gonzalez-Mora Manuel Mas 《Biology of reproduction》2002,66(1):185-189
This study assessed whether the in vivo production of nitric oxide (NO) in the penis is impaired in experimental diabetes and whether this phenomenon can be explained by abnormal levels of NO synthase isoenzymes and/or plasma androgens. Adult male Sprague-Dawley rats were injected with streptozotocin (STZ) (40 mg/kg, i.p.) or vehicle. One half of the STZ-treated animals received daily insulin replacement. Twelve weeks later, the animals were tested for mating behavior and erectile reflexes. They were then anesthetized with urethane (1 g/kg), and the NO levels in their corpora cavernosa were monitored electrochemically with porphyrin microsensors before and after electrostimulation of the cavernous nerve. The intracavernous pressure (ICP) was measured simultaneously. The diabetic animals had substantial impairment in the mating and erectile reflexes tests, decreased basal and stimulated NO levels in the corpora, and a reduced ICP response to cavernous nerve stimulation. Insulin replacement fully reversed the effects of diabetes on the mating reflexes, the basal NO signals, and the ICP responses to electrical field stimulation and partially restored the stimulated NO release. Neither diabetes nor diabetes with insulin treatment had significant effects on serum testosterone levels or NOS isoform (nNOS, eNOS, and iNOS) protein content in penile homogenates, indicating that the changes found in erectile function were independent of such variables. These results also suggest that the diabetes-induced reduction in corporeal NO levels could be mainly due to the lack of some essential cofactors for NOS activity rather than to changes in the amount of enzyme proteins. 相似文献
974.
The present paper describes and illustrates the new speciesAverrhoidium dalyi and provides a key to the species ofAverrhoidium. The new species is known from lowland, terra firme forest in the Purus River basin, in Acre, Brazil, and from Manu National
Park in Madre de Dios, Peru.
Resumen En el presente artículo se describe, discute e ilustra la nueva especieAverrhoidium dalyi coleccionada en la cuenca del Río Purus en el estado de Acre, Brasil y en el Parque Nacional del Manu en el departamento Madre de Dios, Peru. También en el presente se provee una clave para las especies deAverrhoidium.相似文献
975.
One new species ofSerjania (S. erythrocaulis) belonging to theS. paradoxa group ofSerjania sect.Eurycoccus is described and illustrated bringing the total number of species in this group to eight. A second new species,Serjania divaricocca, belonging to sect.Serjania is also described and illustrated.
Resumen Una especie neuva deSerjania (S. erythrocaulis) perteneciente al grupoS. paradoxa de la secciónEurycoccus es descrita e ilustrada. Con esta especie, el numero total de especies conocidas para este grupo aumenta a ocho. Una segunda nueva especie,Serjania divaricocca, perteneciente a la secciónSerjania es también descrita e ilustrada.相似文献
976.
Igual José M Velázquez Encarna Mateos Pedro F. Rodríguez-Barrueco Claudino Cervantes Emilio Martínez-Molina Eustoquio 《Plant and Soil》2001,229(1):35-39
Carboxymethyl cellulase activities were evaluated in eight strains of Frankia from diverse host specificity groups and geographical origins. Cellulase activity was detected in culture supernatants of all strains in the absence of CMC (Carboxymethylcellulose) as an inducer using both double-layer plate and reducing sugar assays, indicating a constitutive production of CM-cellulases by Frankia. CM-cellulase isoenzyme profiles were visualized using activity gel electrophoresis of concentrated culture supernatants. Different electrophoretic profiles were observed among the eight strains tested, which correlate with the host specificity and taxonomic grouping of Frankia. 相似文献
977.
Characterization of Rhizobial Isolates of Phaseolus vulgaris by Staircase Electrophoresis of Low-Molecular-Weight RNA
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Encarna Velzquez Esperanza Martínez-Romero Dulce Nombre Rodríguez-Navarro Martha E. Trujillo Antonio Daza Pedro F. Mateos Eustoquio Martínez-Molina Peter van Berkum 《Applied microbiology》2001,67(2):1008-1010
Low-molecular-weight (LMW) RNA molecules were analyzed to characterize rhizobial isolates that nodulate the common bean growing in Spain. Since LMW RNA profiles, determined by staircase electrophoresis, varied across the rhizobial species nodulating beans, we demonstrated that bean isolates recovered from Spanish soils presumptively could be characterized as Rhizobium etli, Rhizobium gallicum, Rhizobium giardinii, Rhizobium leguminosarum bv. viciae and bv. trifolii, and Sinorhizobium fredii. 相似文献
978.
Igual José M. Valverde Angel Rivas Raúl Mateos Pedro F. Rodríguez-Barrueco C. Martínez-Molina Eustoquio Cervantes Emilio Velázquez Encarna 《Plant and Soil》2003,254(1):115-123
Submergence stimulates elongation of the leaves of Rumex palustris and under laboratory conditions the maximum final leaf length (of plants up to 7 weeks old) was obtained within a 9 day period. This elongation response, mainly determined by petiole elongation, depends on the availability of storage compounds and developmental stage of a leaf. A starch accumulating tap root and mature leaves and petioles were found to supply elongating leaves with substrates for polysaccharide synthesis in expanding cell walls. Changes in the composition of cell wall polysaccharides of elongated petioles suggest a substantial cell wall metabolism during cell extension. Reduced starch levels or removal of mature leaves caused a substantial limitation of submerged leaf growth. From the 5th leaf onward enough reserves were available to perform submerged leaf growth from early developmental stages. Very young petioles had a limited capacity to elongate. In slightly older petioles submergence resulted in the longest final leaf lengths and these values gradually decreased when submergence was started at more mature developmental stages. Submerged leaf growth is mainly a matter of petiole elongation in which cell elongation has a concurrent synthesis of xylem elements in the vascular tissue. Mature petioles still elongated (when submerged) by cell and tissue elongation only: the annular tracheary elements stretched enabling up to 70% petiole elongation. 相似文献
979.
Pedro Daleo 《Journal of experimental marine biology and ecology》2003,291(2):255-267
In this paper, we address the question of whether the presence of the burrowing crab Chasmagnathus granulatus affects the habitat use of the fiddler crab Uca uruguayensis. Field samples showed that the species have a disjoint spatial distribution. Male fiddler crab density decreased in zones with C. granulatus, however, female density increased. Male fiddler crabs avoided feeding on sediment affected by C. granulatus and were more preyed. Predation was higher during the fiddler crab reproductive season and, probably due to predation risk, males showed lower reproductive display in shared zones. Field experiments shows that when C. granulatus were excluded, densities of U. uruguayensis increased mainly due to an increase in density of males. Habitat differentiation of these species may be because C. granulatus affects U. uruguayensis in several ways, including direct predation, disturbance and behavioural changes associated to predation risk. Males and females are affected differentially probably because of the extreme sexual dimorphism of this crab species. Coloration on enlarged claw and waving activities are all factors that increase predation risk for male and the presence of only one feeding claw may increase sediment-mediated effects. 相似文献
980.
Margarida Castro Pedro EncarnaçãoOliver Tully 《Journal of experimental marine biology and ecology》2002,269(1):53-64
Lipofuscin accumulation is associated with ageing at the subcellular level. A strong correlation between lipofuscin and age has been found in crustaceans using histological techniques. This association has been proposed as the basis for a methodology to age crustaceans and in some cases lipofuscin levels were found to be better correlated with age than size. The experiment presented here was designed to test the potential effect of diet, in particular dietary antioxidants, on lipofuscin accumulation and age estimation.The shrimp, Penaeus japonicus, was reared in an aquaculture facility and fed commercial pellets with modified vitamins C and E contents. One group was fed with levels of vitamins C and E of 1000 and 150 mg/kg, respectively, and another group with 2500 and 5000 mg/kg, respectively. The experiment started when the shrimp were 19 weeks old. Samples were obtained at this point and at ages 33 and 43 weeks. Lipofuscin was measured in the nerve cords (antennal neuropils and oesophageal connectives) in an area adjacent to the brain.Dietary antioxidants significantly affected lipofuscin levels. High vitamin content in the diet resulted in lower percentage of the observed area covered with lipofuscin, lower lipofuscin granule density and lower average granule size. Gender had no effect on any of these variables and granule size did not significantly change within each treatment. Lipofuscin area and granule density increased with age in both vitamin treatments.These results suggest that age estimation using lipofuscin indices may be biased when: (1) wild populations are dispersed over diverse environments; (2) the age estimation of wild individuals is based on the results obtained using laboratory-reared individuals. 相似文献