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51.
52.
Koumbi D Clement JC Sideratou Z Yaouanc JJ Loukopoulos D Kollia P 《Biochimica et biophysica acta》2006,1760(8):1151-1159
A series of cationic liposomes known as cationic phosphonolipids (CPs) were evaluated as vehicles for in vitro gene transfer in K562 erythroleukemia cells and 5637 epithelial carcinoma cells. For each CP and target cell type examined, detailed analyses were performed to determine optimal transfection conditions (lipid/ DNA (+/-) charge ratio, amount of complexed episomal DNA, liposomal and lipoplex size, complexation medium and duration of complex-cell exposure time). Lipofection conditions were determined to be both cell- and lipid-type specific. Complexation medium critically affected transfection competence. The initial size of the liposome was not always predictive of lipofection potency. The lipid chemical composition had a strong impact upon lipofection efficiency; DOPE inclusion in the liposome formulations was found to affect the levels of transgene expression in a cell-dependent way. Notably, effective transgene expression was characterized by prominent plasmid nuclear incorporation. Human A gamma- and epsilon-globin transgene nuclear incorporation and expression in 5637 cells post GLB.391-mediated lipofection lends credence to its use as a vehicle of therapeutic transgene delivery. 相似文献
53.
Background
Early deafness leads to enhanced attention in the visual periphery. Yet, whether this enhancement confers advantages in everyday life remains unknown, as deaf individuals have been shown to be more distracted by irrelevant information in the periphery than their hearing peers. Here, we show that, in a complex attentional task, a performance advantage results for deaf individuals.Methodology/Principal Findings
We employed the Useful Field of View (UFOV) which requires central target identification concurrent with peripheral target localization in the presence of distractors – a divided, selective attention task. First, the comparison of deaf and hearing adults with or without sign language skills establishes that deafness and not sign language use drives UFOV enhancement. Second, UFOV performance was enhanced in deaf children, but only after 11 years of age.Conclusions/Significance
This work demonstrates that, following early auditory deprivation, visual attention resources toward the periphery slowly get augmented to eventually result in a clear behavioral advantage by pre-adolescence on a selective visual attention task. 相似文献54.
Beenken KE Dunman PM McAleese F Macapagal D Murphy E Projan SJ Blevins JS Smeltzer MS 《Journal of bacteriology》2004,186(14):4665-4684
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A comparative study of protein synthesis has been carried out with embryos excised from dormant (D) and non-dormant (ND) caryopses of the wild oat. Although D embryos imbibed in water or ND embryos imbibed in abscisic acid do not germinate, they incorporate [14C]leucine into TCA-insoluble material for the first 48 h as readily as embryos that do germinate (ND embryos imbibed in water, or D embryos imbibed in gibberellic acid). Pulsechase experiments with [14]leucine show that in both D and ND embryos the proteins associated with the membranes undergo turnover. The rates of decay of incorporated radioactivity are similar in both dormant and germinating embryos up to 98 h following embryo excision. Fractionation of the membrane proteins in SDS-polyacrylamide gels indicates that the different polypeptides have different rates of turnover. It is concluded that membrane proteins in imbibed D embryos are in a state of constant turnover, and that this is a part of the replacement processes necessary to maintain the integrity of hydrated cells. The continuation of such synthetic events could account for long term survival of dormant Avena fatua in the imbibed state.Abbreviations CCRSE
cytochrome relative stain equivalents
- D
dormant
- ND
nondormant
- ABA
abscisic acid
- GA
gibberellic acid GA3 相似文献
57.
Stephanie J. Salyer Esther M. Ellis Corvil Salomon Christophe Bron Stanley Juin Ryan R. Hemme Elizabeth Hunsperger Emily S. Jentes Roc Magloire Kay M. Tomashek Anne Marie Desormeaux Jorge L. Mu?oz-Jordán Lesly Etienne Manuela Beltran Tyler M. Sharp Daphne Moffett Jordan Tappero Harold S. Margolis Mark A. Katz 《PLoS neglected tropical diseases》2014,8(10)
In October 2012, the Haitian Ministry of Health and the US CDC were notified of 25 recent dengue cases, confirmed by rapid diagnostic tests (RDTs), among non-governmental organization (NGO) workers. We conducted a serosurvey among NGO workers in Léogane and Port-au-Prince to determine the extent of and risk factors for dengue virus infection. Of the total 776 staff from targeted NGOs in Léogane and Port-au-Prince, 173 (22%; 52 expatriates and 121 Haitians) participated. Anti-dengue virus (DENV) IgM antibody was detected in 8 (15%) expatriates and 9 (7%) Haitians, and DENV non-structural protein 1 in one expatriate. Anti-DENV IgG antibody was detected in 162 (94%) participants (79% of expatriates; 100% of Haitians), and confirmed by microneutralization testing as DENV-specific in 17/34 (50%) expatriates and 42/42 (100%) Haitians. Of 254 pupae collected from 68 containers, 65% were Aedes aegypti; 27% were Ae. albopictus. Few NGO workers reported undertaking mosquito-avoidance action. Our findings underscore the risk of dengue in expatriate workers in Haiti and Haitians themselves. 相似文献
58.
The rapidly evolving field of plant centromeres 总被引:9,自引:0,他引:9
Meiotic and mitotic chromosome segregation are highly conserved in eukaryotic organisms, yet centromeres--the chromosomal sites that mediate segregation--evolve extremely rapidly. Plant centromeres have DNA elements that are shared across species, yet they diverge rapidly through large- and small-scale changes. Over evolutionary time-scales, centromeres migrate to non-centromeric regions and, in plants, heterochromatic knobs can acquire centromere activity. Discerning the functional significance of these changes will require comparative analyses of closely related species. Combined with functional assays, continued efforts in plant genomics will uncover key DNA elements that allow centromeres to retain their role in chromosome segregation while allowing rapid evolution. 相似文献
59.
Recent evidence demonstrates that interactions between different integrins that are present on the cell surface can strongly influence the adhesive function of individual receptors. In this report, we show that Chinese hamster ovary cells that express the integrin alphavbeta3 in the absence of alpha5beta1 demonstrate increased adhesion and migration on fibrinogen. Furthermore, alphavbeta3-mediated adhesion to fibrinogen is not augmented by the soluble agonist, MnCl2, suggesting that alphavbeta3 exists in a higher affinity state in these cells. De novo expression of wild-type alpha5beta1 negatively regulates alphavbeta3-mediated adhesion and migration. This effect is not seen with expression of a chimeric alpha5beta1 integrin in which the cytoplasmic portion of the alpha5 integrin subunit is replaced by the cytoplasmic portion of the alpha4 integrin. In addition, it does not require ligation of alpha5beta1 by fibronectin. Cells that express a constitutively active beta3 integrin that contains a point mutation in the conserved membrane proximal region of the cytoplasmic tail, D723R, are resistant to the effect of alpha5beta1 expression. These data provide additional evidence of "cross-talk" between the integrins alpha5beta1 and alphavbeta3, and support the idea that alpha5beta1 regulates alphavbeta3-mediated ligand binding. This provides a relevant biological mechanism whereby variations in alpha5beta1 expression in vivo may modulate activation of alphavbeta3 to influence its adhesive function. 相似文献
60.
In this study, we quantitatively examined male sexual behavior in relation to fecal estrogen and progesterone concentrations in female Mohor gazelles. We investigated the hypothesis that, during natural mating, males detect cues relating to the potential for successful conception and pregnancy. Time series analysis revealed that males could detect the approach of estrus 2-3 days before female fecal estrogens and estrogen/progestagen (E/P) ratio reached their peak values. Males also paid closer attention to those females excreting higher fecal estrogen concentrations. Mounting and copulation frequencies were positively correlated with both peri-ovulatory fecal estrogen concentrations, and the frequency of pre-copulatory courtship behaviors. These data suggested that males invest their reproductive effort selectively by mating the most fertile females, assuming that estrogen is a valid index of fertility. This assumption was investigated by examining sequential phases of the reproductive cycle for evidence that oocytes and follicles produced in a more estrogenic environment would lead to the formation of the most competent corpora lutea, thereby maximizing the chance of sustaining pregnancy. Associations between sexual behavior and hormone excretion support the hypothesis that males may use this mechanism to assess female fertility. 相似文献