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991.
Puerma E Acosta MJ Barragán MJ Martínez S Marchal JA Bullejos M Sánchez A 《Genetica》2008,134(3):287-295
The karyotype of individuals of the species Rhinolophus hipposideros from Spain present a chromosome number of 2n = 54 (NFa = 62). The described karyotype for these specimens is very similar to another previously described in individual
from Bulgaria. However, the presence of one additional pair of autosomal acrocentric chromosomes in the Bulgarian karyotype
and the differences in X chromosome morphology indicated that we have described a new karyotype variant in this species. In
addition, we have analyzed several clones of 1.4 and 1 kb of a PstI repeated DNA sequence from the genome of R. hipposideros. The repeated sequence included a region with high identity with the 5S rDNA genes and flanking regions, with no homology
with GenBank sequences. Search for polymerase III regulatory elements demonstrated the presence of type I promoter elements
(A-box, Intermediate Element and C-box) in the 5S rDNA region. In addition, upstream regulatory elements, as a D-box and Sp1
binding sequences, were present in flanking regions. All data indicated that the cloned repeated sequences are the functional
rDNA genes from this species. Finally, FISH demonstrated the presence of rDNA in nine chromosome pairs, which is surprising
as most mammals have only one carrier chromosome pair. 相似文献
992.
Paola Rebuzzini Tui Neri Maurizio Zuccotti Carlo Alberto Redi Silvia Garagna 《Cytotechnology》2008,58(1):17-23
Although mouse embryonic stem cell lines (mESCs) have been established since 1981, systematic studies about chromosomal changes
during culture are lacking. In this study, we report the results of a cytogenetic analysis performed on three mESC lines (named
UPV02, UPV06 and UPV08) cultured for a period of 3 months. At time intervals, the variation of the chromosome number together
with the expression of markers of the undifferentiated status, i.e., OCT-4, SSEA-1, FOM-1 and alkaline phosphatase activity,
were determined. The three mESC lines showed a progressive loss of euploid metaphases during the 3 months period of culture.
Chromosome abnormalities were accumulated at the latest passages analysed. Metacentric chromosomes were the most frequent
chromosome abnormality observed throughout the period of culture. Interestingly, in coincidence with, or few passages after,
the drop of euploidy, the alkaline phosphatase activity was partially or totally lost, whereas the OCT-4, SSEA-1 and FOM-1
stem markers were always positive throughout the period of culture. Our results remark the necessity to perform the karyotype
analysis during culture in order to develop new culture conditions to maintain the correct chromosome complement in long-term
culture of mESC lines. 相似文献
993.
Murciano C Yáñez A O'Connor JE Gozalbo D Gil ML 《FEMS immunology and medical microbiology》2008,53(2):214-221
Previous work by our group showed that aged C57BL/6 mice develop an altered innate and adaptive immune response to Candida albicans and are more susceptible to systemic primary candidiasis. In this work, we used young (2-3 months old) and aged (18-20 months old) C57BL/6 mice to study in vitro the influence of aging on (1) the fungicidal activity of neutrophils and macrophages, (2) the production of cytokines by resident peritoneal macrophages in response to C. albicans, and (3) cell surface Toll-like receptor (TLR) 2 expression on resident peritoneal macrophages. Our results indicate that murine phagocytes have a fungicidal activity well preserved with aging. In vitro production of proinflammatory cytokines (IL-6, IL-1beta, and tumor necrosis factor-alpha and chemokines (MIP-2) by purified (CD11b(+)) peritoneal macrophages in response to yeasts and hyphae of C. albicans was significantly lower in aged mice as compared with young mice. However, the production of IL-10 by macrophages, in response to C. albicans, was similar in both young and aged animals. Moreover, baseline TLR2 surface expression level was lower on aged macrophages than on control macrophages. Taken together, these data indicate that the increased susceptibility to C. albicans disseminated infections in aged mice is correlated with defects in TLR2 expression and in cytokine production, but not with an impaired fungicidal activity. 相似文献
994.
The trans-Golgi network (TGN) is one of the main, if not the main, sorting stations in the process of intracellular protein trafficking.
It is therefore of central importance to understand how the key players in the TGN-based sorting and delivery process, the
post-Golgi carriers (PGCs), form and function. Over the last few years, modern morphological approaches have generated new
insights into the questions of PGC biogenesis, structure and dynamics. Here, we present a view by which the “lifecycle” of
a PGC consists of several distinct stages: the formation of TGN tubular export domains (where different cargoes are segregated
from each other and from the Golgi enzymes); the docking of these tubular domains onto molecular motors and their extrusion
towards the cell periphery along microtubules; the fission of the forming PGC from the donor membrane; and the delivery of
the newly formed PGC to its specific acceptor organelle. It is now important to add the many molecular machineries that have
been described as operating at the TGN to this “morphofunctional map” of the TGN export process. 相似文献
995.
Iglesias R Locovei S Roque A Alberto AP Dahl G Spray DC Scemes E 《American journal of physiology. Cell physiology》2008,295(3):C752-C760
Pannexin 1 (Panx1), an ortholog to invertebrate innexin gap junctions, has recently been proposed to be the pore induced by P2X(7) receptor (P2X(7)R) activation. We explored the pharmacological action of compounds known to block gap junctions on Panx1 channels activated by the P2X(7)R and the mechanisms involved in the interaction between these two proteins. Whole cell recordings revealed distinct P2X(7)R and Panx1 currents in response to agonists. Activation of Panx1 currents following P2X(7)R stimulation or by membrane depolarization was blocked by Panx1 small-interfering RNA (siRNA) and with mefloquine > carbenoxolone > flufenamic acid. Incubation of cells with KN-62, a P2X(7)R antagonist, prevented current activation by 2'(3')-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP). Membrane permeabilization to dye induced by BzATP was also prevented by Panx1 siRNA and by carbenoxolone and mefloquine. Membrane permeant (TAT-P2X(7)) peptides, provided evidence that the Src homology 3 death domain of the COOH-terminus of the P2X(7)R is involved in the initial steps of the signal transduction events leading to Panx1 activation and that a Src tyrosine kinase is likely involved in this process. Competition assays indicated that 20 muM TAT-P2X(7) peptide caused 50% reduction in Src binding to the P2X(7)R complex. Src tyrosine phosphorylation following BzATP stimulation was reduced by KN-62, TAT-P2X(7) peptide, and by the Src tyrosine inhibitor PP2 and these compounds prevented both large-conductance Panx1 currents and membrane permeabilization. These results together with the lack Panx1 tyrosine phosphorylation in response to P2X(7)R stimulation indicate the involvement of an additional molecule in the tyrosine kinase signal transduction pathway mediating Panx1 activation through the P2X(7)R. 相似文献
996.
We present a systematic study of B-DNA flexibility in aqueous solution using long-scale molecular dynamics simulations with the two more recent versions of nucleic acids force fields (CHARMM27 and parmbsc0) using four long duplexes designed to contain several copies of each individual base pair step. Our study highlights some differences between pambsc0 and CHARMM27 families of simulations, but also extensive agreement in the representation of DNA flexibility. We also performed additional simulations with the older AMBER force fields parm94 and parm99, corrected for non-canonical backbone flips. Taken together, the results allow us to draw for the first time a consensus molecular dynamics picture of B-DNA flexibility. 相似文献
997.
998.
Ambra Quacchia Chiara Ferracini Simona Bonelli Emilio Balletto Alberto Alma 《Biodiversity and Conservation》2008,17(6):1429-1437
Cacyreus marshalli Butler is an invasive species in many parts of Europe and Mediterranean area. In Europe, its larvae normally feed on pelargoniums.
We investigated its potential to spread to native Geranium spp. and evaluated the conservation risks that such a shift would pose for both native geraniums and cohabitant butterflies.
The host plant preferences of the Geranium Bronze were investigated under controlled conditions. Studies included both no-choice
and multi-choice tests, respectively using 9 and 6 Italian native Geranium spp. Host plant preferences were evaluated by counting the number of eggs laid on individual plants and following butterfly
development until adult emergence. Under no-choice conditions, at least one egg was recorded on each tested plant, except
for G. phaeum L. All the plants on which oviposition occurred were fully suitable for larval development. The butterfly, however, clearly
preferred three species, i.e. G. pratense L., G. sanguineum L. and G. sylvaticum L. for oviposition. In multi-choice trials, females laid at least one egg on all the tested plants, with a preference for
G. pratense and G. sylvaticum. In presence of Pelargonium spp. plants, however, no oviposition was observed on any Geranium spp. We assessed offspring fitness measuring their wingspan. No statistical differences were detected in the wingspan between
adults emerged from Geranium and Pelargonium. Cacyreus marshalli represents a potential threat for both native geraniums and for Geranium-consuming lycaenids, such as Aricia nicias Meigen and Eumedonia eumedon Esper. 相似文献
999.
Lucia Acebey Amira Apaza Rosy de Michel Stephan Beck Valérie Jullian Grace Ruiz Alberto Gimenez Séverine Chevalley Michel Sauvain 《Biodiversity and Conservation》2008,17(8):1853-1859
Developing countries with a rich biodiversity want to control the use of this natural patrimony, especially in the research
of natural compounds of pharmaceutical interest. Here we present the organization of six permanent plots in a mountain tropical
forest on the east side of the Andean Cordillera in Bolivia, and their role in the discovery of plants with antiplasmodial
or antileishmanial activities. Permanent plots are widely used in ecological survey, but rarely in bioprospecting. This set-up
allows Bolivian authorities to control the bioprospecting, and facilitates further chemical studies on the bioactive plants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Lucia Acebey and Amira Apaza have contributed equally to this work. 相似文献
1000.
Yadvinder Malhi Timothy R. Baker Oliver L. Phillips Samuel Almeida Esteban Alvarez Luzmilla Arroyo Jerome Chave Claudia I. Czimczik Anthony Di Fiore Niro Higuchi Timothy J. Killeen Susan G. Laurance William F. Laurance Simon L. Lewis Lina María Mercado Montoya Abel Monteagudo David A. Neill Percy Núez Vargas Sandra Patio Nigel C.A. Pitman Carlos Alberto Quesada Rafael Salomo Jos Natalino Macedo Silva Armando Torres Lezama Rodolfo Vsquez Martínez John Terborgh Barbara Vinceti Jon Lloyd 《Global Change Biology》2004,10(5):563-591
The net primary production of tropical forests and its partitioning between long‐lived carbon pools (wood) and shorter‐lived pools (leaves, fine roots) are of considerable importance in the global carbon cycle. However, these terms have only been studied at a handful of field sites, and with no consistent calculation methodology. Here we calculate above‐ground coarse wood carbon productivity for 104 forest plots in lowland New World humid tropical forests, using a consistent calculation methodology that incorporates corrections for spatial variations in tree‐size distributions and wood density, and for census interval length. Mean wood density is found to be lower in more productive forests. We estimate that above‐ground coarse wood productivity varies by more than a factor of three (between 1.5 and 5.5 Mg C ha?1 a?1) across the Neotropical plots, with a mean value of 3.1 Mg C ha?1 a?1. There appear to be no obvious relationships between wood productivity and rainfall, dry season length or sunshine, but there is some hint of increased productivity at lower temperatures. There is, however, also strong evidence for a positive relationship between wood productivity and soil fertility. Fertile soils tend to become more common towards the Andes and at slightly higher than average elevations, so the apparent temperature/productivity relationship is probably not a direct one. Coarse wood productivity accounts for only a fraction of overall tropical forest net primary productivity, but the available data indicate that it is approximately proportional to total above‐ground productivity. We speculate that the large variation in wood productivity is unlikely to directly imply an equivalent variation in gross primary production. Instead a shifting balance in carbon allocation between respiration, wood carbon and fine root production seems the more likely explanation. 相似文献