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991.
Both symmetric and asymmetric divisions rely on alignment of the mitotic spindle with cues from the environment. A study now shows that mitotic spindles find their position by reading the map of forces that load-bearing retraction fibres exert on the cell body. 相似文献
992.
993.
One limitation for the study of chromosomal fragile sites is that they must be studied on metaphase spreads, after the breakage. We show here that bacterial lac operator (lacO) repeats are prone to spontaneous breakage, which when combined with a fluorescent lac repressor (lacR) has allowed us to track a fragile site through the cell cycle. By using this system, we show that Plk1-interacting checkpoint helicase (PICH) is already present at fragile sites during interphase, suggesting roles for this helicase beyond mitosis. In addition, we report that the oncogene Myc promotes the formation of anaphase bridges and micronuclei containing fragile-site sequences. 相似文献
994.
Bartolome Bejarano Mariangela Bianco Dolores Gonzalez-Moron Jorge Sepulcre Joaquin Goñi Juan Arcocha Oscar Soto Del Ubaldo Carro Giancarlo Comi Letizia Leocani Pablo Villoslada 《BMC neurology》2011,11(1):1-9
Background
Conventional magnetic resonance imaging (MRI) has improved the diagnosis and monitoring of multiple sclerosis (MS). In clinical trials, MRI has been found to detect treatment effects with greater sensitivity than clinical measures; however, clinical and MRI outcomes tend to correlate poorly.Methods
In this observational study, patients (n = 550; 18-50 years; relapsing-remitting MS [Expanded Disability Status Scale score ≤4.0]) receiving interferon (IFN) β-1a therapy (44 or 22 µg subcutaneously [sc] three times weekly [tiw]) underwent standardized MRI, neuropsychological and quality-of-life (QoL) assessments over 3 years. In this post hoc analysis, MRI outcomes and correlations between MRI parameters and clinical and functional outcomes were analysed.Results
MRI data over 3 years were available for 164 patients. T2 lesion and T1 gadolinium-enhancing (Gd+) lesion volumes, but not black hole (BH) volumes, decreased significantly from baseline to Year 3 (P < 0.0001). Percentage decreases (baseline to Year 3) were greater with the 44 μg dose than with the 22 μg dose for T2 lesion volume (-10.2% vs -4.5%, P = 0.025) and T1 BH volumes (-7.8% vs +10.3%, P = 0.002). A decrease in T2 lesion volume over 3 years predicted stable QoL over the same time period. Treatment with IFN β-1a, 44 μg sc tiw, predicted an absence of cognitive impairment at Year 3.Conclusion
Subcutaneous IFN β-1a significantly decreased MRI measures of disease, with a significant benefit shown for the 44 µg over the 22 µg dose; higher-dose treatment also predicted better cognitive outcomes over 3 years. 相似文献995.
Chen K Xu Y Rana S Miranda OR Dubin PL Rotello VM Sun L Guo X 《Biomacromolecules》2011,12(7):2552-2561
The binding of bovine serum albumin (BSA) and β-lactoglobulin (BLG) to TTMA (a cationic gold nanoparticle coupled to 3,6,9,12-tetraoxatricosan-1-aminium, 23-mercapto-N,N,N-trimethyl) was studied by high-resolution turbidimetry (to observe a critical pH for binding), dynamic light scattering (to monitor particle growth), and isothermal titration calorimetry (to measure binding energetics), all as a function of pH and ionic strength. Distinctively higher affinities observed for BLG versus BSA, despite the lower pI of the latter, were explained in terms of their different charge anisotropies, namely, the negative charge patch of BLG. To confirm this effect, we studied two isoforms of BLG that differ in only two amino acids. Significantly stronger binding to BLGA could be attributed to the presence of the additional aspartates in the negative charge domain for the BLG dimer, best portrayed in DelPhi. This selectivity decreases at low ionic strength, at which both isoforms bind well below pI. Selectivity increases with ionic strength for BLG versus BSA, which binds above pI. This result points to the diminished role of long-range repulsions for binding above pI. Dynamic light scattering reveals a tendency for higher-order aggregation for TTMA-BSA at pH above the pI of BSA, due to its ability to bridge nanoparticles. In contrast, soluble BLG-TTMA complexes were stable over a range of pH because the charge anisotropy of this protein at makes it unable to bridge nanoparticles. Finally, isothermal titration calorimetry shows endoenthalpic binding for all proteins: the higher affinity of TTMA for BLGA versus BLGB comes from a difference in the dominant entropy term. 相似文献
996.
997.
Natalia Sastre Carles Vilà María Salinas Vladimir V. Bologov Vicente Urios Armand Sánchez Olga Francino Oscar Ramírez 《Conservation Genetics》2011,12(3):701-712
Monitoring the loss of genetic diversity in wild populations after a bottleneck event is a priority in conservation and management
plans. Here, we used diverse molecular markers to search for signatures of demographic bottlenecks in two wolf populations;
an isolated population from the Iberian Peninsula and a non-isolated population from European Russia. Autosomal, mtDNA and
Y-chromosomal diversity and the effective population size (Ne) were significantly lower in the Iberian population. Neutrality tests using mtDNA sequences, such as R2, Fu and Li’s F*, Tajima’s D and Fu’s Fs, were positively significant in the Iberian population, suggesting a population decline, but were not significant for the
Russian population, likely due to its larger effective population size. However, three tests using autosomal data confirmed
the occurrence of the genetic bottleneck in both populations. The M-ratio test was the only one providing significant results for both populations. Given the lack of consistency among the different
tests, we recommend using multiple approaches to investigate possible past bottlenecks. The small effective population size
(about 50) in the Iberian Peninsula compared to the presumed extant population size could indicate that the bottleneck was
more powerful than initially suspected or an overestimation of the current population. The risks associated with small effective
population sizes suggest that the genetic change in this population should be closely monitored in the future. On the other
hand, the relatively small effective population size for Russian wolves (a few hundred individuals) could indicate some fragmentation,
contrary to what is commonly assumed. 相似文献
998.
Côté HC Gerschenson M Walker UA Miro O Garrabou G Hammond E Villarroya J Giralt M Villarroya F Cinque P Garcia-Arumi E Andreu AL Pinti M Cossarizza A 《Mitochondrion》2011,11(3):520-527
Mitochondrial DNA quantification by qPCR is used in the context of many diseases and toxicity studies but comparison of results between laboratories is challenging. Through two multigroup distributions of DNA samples from human cell lines, the MITONAUTS group anonymously compared mtDNA/nDNA quantification across nine laboratories involved in HIV research worldwide. Eight of the nine sites showed significant correlation between them (mean raw data R(2)=0.664; log(10)-transformed data R(2)=0.844). Although mtDNA/nDNA values were well correlated between sites, the inter-site variability on the absolute measurements remained high with a mean (range) coefficient of variation of 71 (37-212) %. Some variability appeared cell line-specific, probably due to chromosomal alterations or pseudogenes affecting the quantification of certain genes, while within cell line variability was likely due to differences in calibration of the standard curves. The use of two mtDNA and two single copy nDNA genes with highly specific primers to quantify each genome would help address copy number variants. Our results indicate that sample shipment must be done frozen and that absolute mtDNA/nDNA ratio values cannot readily be compared between laboratories, especially if assessing cultured cell mtDNA content. However, within laboratory and relative mtDNA/nDNA comparisons between laboratories should be reliable. 相似文献
999.
Choi S Toledo LI Fernandez-Capetillo O Bakkenist CJ 《DNA Repair》2011,10(10):1000-1; author reply 1002
1000.