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101.
Herein, we report the biochemical and functional characterization of a novel Ca(2+)-activated nucleoside diphosphatase (apyrase), CApy, of the intracellular gut pathogen Cryptosporidium. The purified recombinant CApy protein displayed activity, substrate specificity and calcium dependency strikingly similar to the previously described human apyrase, SCAN-1 (soluble calcium-activated nucleotidase 1). CApy was found to be expressed in both Cryptosporidium parvum oocysts and sporozoites, and displayed a polar localization in the latter, suggesting a possible co-localization with the apical complex of the parasite. In vitro binding experiments revealed that CApy interacts with the host cell in a dose-dependent fashion, implying the presence of an interacting partner on the surface of the host cell. Antibodies directed against CApy block Cryptosporidium parvum sporozoite invasion of HCT-8 cells, suggesting that CApy may play an active role during the early stages of parasite invasion. Sequence analyses revealed that the capy gene shares a high degree of homology with apyrases identified in other organisms, including parasites, insects and humans. Phylogenetic analysis argues that the capy gene is most likely an ancestral feature that has been lost from most apicomplexan genomes except Cryptosporidium, Neospora and Toxoplasma. 相似文献
102.
Garrido N Pérez-Martos A Faro M Lou-Bonafonte JM Fernández-Silva P López-Pérez MJ Montoya J Enríquez JA 《The Biochemical journal》2008,414(1):93-102
Cisplatin accumulates in mitochondria, which are a major target for this drug in cancer cells. Thus alterations in mitochondrial function have been implicated in cancer cell resistance to chemotherapeutic agents. Moreover, cisplatin toxic side effects seem to be associated with mitochondrial injury in vivo and in vitro. In order to clarify the potential effect of cisplatin in mtDNA (mitochondrial DNA) maintenance and expression, we have analysed rat liver mtDNA and mtRNA (mitochondrial RNA) synthesis as well as their stability under the influence of in vivo treatment or in vitro exposure to cisplatin. We show that cisplatin causes a direct and significant impairment of mtDNA and mtRNA synthesis and decreases steady-state levels of mtRNAs in isolated mitochondria. Furthermore, in vivo treatment of the animals with cisplatin exerts a protective effect from the impairment of mtRNA metabolism caused by in vitro exposure to the drug, by means of increased mitochondrial GSH levels after in vivo cisplatin treatment. 相似文献
103.
104.
The bacterial genus Brucella consists of a group of facultative intracellular pathogens which produces abortion and infertility in animals and a chronic debilitating febrile illness in humans. BMFP is a basic protein of Brucella abortus that belongs to a highly conserved group of homologue proteins of unknown structure and function in proteobacteria (COG2960). In this study, we report the structural and biochemical characterization of this protein. We found that BMFP has two structural domains: a carboxyl-terminal coiled-coil domain through which the protein self-associates as a trimer and a natively disordered amino-terminal domain which has propensity to adopt an amphipathic alpha-helical structure. This natively unfolded domain undergoes a structural rearrangement from unfolded to alpha-helix in the presence of high ionic strength, acidic pH, detergents, and phospholipid vesicles. Moreover, we demonstrated that the interaction of BMFP with phospholipid vesicles promotes in vitro membrane fusion. These results contribute to the elucidation of the structural and functional properties of this protein and its homologues present in most proteobacteria. 相似文献
105.
Bradley J. Erickson Patricio Fajnwaks Steve G. Langer John Perry 《Translational oncology》2014,7(1):36-39
The execution of a multisite trial frequently includes image collection. The Clinical Trials Processor (CTP) makes removal of protected health information highly reliable. It also provides reliable transfer of images to a central review site. Trials using central review of imaging should consider using CTP for handling image data when a multisite trial is being designed. 相似文献
106.
107.
Patricio H. Manríquez Ricardo Guiñez Alberto Olivares Marcela Clarke Juan Carlos Castilla 《Marine Biology Research》2018,14(5):462-477
Reproduction in tunicates is considered to be particularly vulnerable to changes in seawater temperature. In the present study we investigated the effects of sea surface temperature and temperature anomalies on reproductive traits of the non-native sessile tunicate Pyura praeputialis. Reproductive traits of this species were investigated over the course of 67 months, based on samples collected at two localities (eastern and western shorelines) of the Bay of Antofagasta. The study period included years with different oceanic and atmospheric conditions: a warm event, El Niño (June 1997 to July 1998); a cold event, La Niña (August 1998 to December 2000); and post-La Niña (January 2000 to December 2002). We compared two common indices (condition and gonadosomatic) and histological sections to evaluate the maximum reproduction index of this introduced species that dominates a large part of the rocky intertidal habitat in the Bay of Antofagasta. We found sexually mature individuals all year-round and a decrease in both reproductive indices matching the reduction in the sea surface temperature during the austral autumn and winter months. The results suggest that gonad development in this species is sensitive to sea surface temperature and thermal anomalies. We conclude that future thermal anomalies or projected global average sea surface warming associated with climate change might have no negative consequences on these reproductive traits of P. praeputialis. This suggests this species is ecologically resilient and that the ecosystem services that this species provides for other invertebrate and algal species will be maintained. 相似文献
108.
Sebastian A. Klarian Carlos Canales-Cerro Patricio Barría Patricia Zárate Francisco Concha Sebastián Hernández 《Marine Biology Research》2018,14(2):173-182
The blue shark (Prionace glauca) and the shortfin mako shark (Isurus oxyrinchus) are two large and highly migratory sharks distributed in most oceans. Although they are often caught in the south Pacific Ocean long-line fisheries, their trophic ecology is poorly understood. Stable isotopes with Bayesian mixing and dependence concentration models were performed to determine the diet and trophic differences between the two species in the South-eastern Pacific Ocean. According to the mixing models, fishes are the most important prey of these sharks. Dolphin calves and remains were found in the stomachs of both species, which represents a novel finding in trophic ecology of South Pacific sharks. Intra-specific differences were found in P. glauca, but not in specimens of I. oxyrinchus. The two sharks showed a high degree of diet overlap (73%), primarily over mackerel and dolphin carcasses. Our results indicate that blue and shortfin mako sharks have a generalist feeding strategy in the eastern Pacific Ocean, with a strong preference for teleost fishes and also for dolphin carcasses. Therefore, trophic studies are useful to understand energy flow through the food web, and the trophic position of key species. 相似文献
109.
Top predator fish assemblages in Northern Patagonia,Argentina. What factors regulate their patterns of distribution and abundance?
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María Valeria Fernández Mailén Lallement Magalí Rechencq Pablo H. Vigliano Alejandro Sosnovsky Patricio J. Macchi 《Austral ecology》2018,43(6):651-662
According to assemblage theory, three factors regulate fish biogeography: restriction of dispersion, environmental restrictions and biotic interactions. The first two factors act on a regional scale and delimit the area of action of the third, which operates on a local scale. Salmonid introductions began in Patagonia in 1904, and this has led to a restructuring of trophic webs and an increase in the number of top predators. This situation allowed us to evaluate, in a natural setting, how communities are formed on different geographic scales. We studied two large basins in Patagonia, situated close to each other but with different assemblages of top predatory fish. We hypothesized that differences in the structuring of the top predator assemblages between and within the basins are due to 1) environmental factors and dispersion processes facilitated by connectivity on a regional scale; and 2) biotic interaction (internal dynamics) between native perch and salmonids, the former acting as a modulator of the top predator assemblages on a local scale. To test these hypotheses, we analysed the top predator assemblages of 16 lakes and one reservoir, as well as their environmental characteristics. We performed a cluster analysis and related the resulting assembly groups to environmental factors by means of a tree model. We also analysed fish diets, using a similarities test to study biotic interactions. On regional and local scales, water basin, degree of connectivity, area, temperature and Zoogeographic integrity coefficient (ZIC) were important factors in the structuring of top predator assemblages. On a local scale, creole perch modulates the salmonid populations through feeding and the consequent distribution of resources. Our work showed that the structure of top predator assemblages was determined by a combination of local and regional factors acting in synergy, as postulated by the assemblage theory. 相似文献
110.
Genetic diversity and geographical dispersal in grapevine clones revealed by microsatellite markers.
Intravarietal genetic diversification associated with geographical dispersal of a vegetatively propagated species was studied using grapevine Vitis vinifera L. 'Cabernet Sauvignon' as a model. Fifty-nine clonal samples obtained from 7 countries (France, Chile, Spain, Australia, Hungary, USA, and Italy) were analyzed using 84 microsatellite markers. Eighteen polymorphic microsatellite loci (21.4%) were detected, finding 22 different genotypes in the population analyzed with a genetic similarity of over 97%. The presence of chimeric clones was evidenced at locus VMC5g7 by means of a segregation analysis of descendants by self-pollination of a triallelic Chilean clone and by somatic embryogenesis analysis, showing a mutation in L2 cell layer. Only 2 clones (obtained from France and Australia) presented the ancestral genotype, and the most divergent genotype was exhibited by another French clone, which had accumulated 5 somatic mutations. The 2 largest populations considered (from France and Chile) showed a clear divergency in the polymorphisms detected. These antecedents enabled the tracing of geographical dispersal with a phylogenetic hypothesis supporting France as the center of origin of diversification of Cabernet Sauvignon. The results obtained could help to explain diversification processes in other grapevine cultivars. The possibility that this kind of genetic variability occurs in other vegetatively propagated species is discussed, focusing on possible fingerprinting applications. 相似文献