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991.
Laia Capilla Nuria Medarde Alexandra Alemany-Schmidt Maria Oliver-Bonet Jacint Ventura Aurora Ruiz-Herrera 《Proceedings. Biological sciences / The Royal Society》2014,281(1786)
Despite the existence of formal models to explain how chromosomal rearrangements can be fixed in a population in the presence of gene flow, few empirical data are available regarding the mechanisms by which genome shuffling contributes to speciation, especially in mammals. In order to shed light on this intriguing evolutionary process, here we present a detailed empirical study that shows how Robertsonian (Rb) fusions alter the chromosomal distribution of recombination events during the formation of the germline in a Rb system of the western house mouse (Mus musculus domesticus). Our results indicate that both the total number of meiotic crossovers and the chromosomal distribution of recombination events are reduced in mice with Rb fusions and that this can be related to alterations in epigenetic signatures for heterochromatinization. Furthermore, we detected novel house mouse Prdm9 allelic variants in the Rb system. Remarkably, mean recombination rates were positively correlated with a decrease in the number of ZnF domains in the Prdm9 gene. The suggestion that recombination can be modulated by both chromosomal reorganizations and genetic determinants that control the formation of double-stranded breaks during meiosis opens new avenues for understanding the role of recombination in chromosomal speciation. 相似文献
992.
New findings about the spatial and temporal use of the Eastern Atlantic Ocean by large juvenile loggerhead turtles 下载免费PDF全文
993.
Nuria Gomez‐Casanovas Tara W. Hudiburg Carl J. Bernacchi William J. Parton Evan H. DeLucia 《Global Change Biology》2016,22(4):1348-1360
Increases in atmospheric nitrogen deposition (Ndep) can strongly affect the greenhouse gas (GHG; CO2, CH4, and N2O) sink capacity of grasslands as well as other terrestrial ecosystems. Robust predictions of the net GHG sink strength of grasslands depend on how experimental N loads compare to projected Ndep rates, and how accurately the relationship between GHG fluxes and Ndep is characterized. A literature review revealed that the vast majority of experimental N loads were higher than levels these ecosystems are predicted to experience in the future. Using a process‐based biogeochemical model, we predicted that low levels of Ndep either enhanced or reduced the net GHG sink strength of most grasslands, but as experimental N loads continued to increase, grasslands transitioned to a N saturation‐decline stage, where the sensitivity of GHG exchange to further increases in Ndep declined. Most published studies represented treatments well into the N saturation‐decline stage. Our model results predict that the responses of GHG fluxes to N are highly nonlinear and that the N saturation thresholds for GHGs varied greatly among grasslands and with fire management. We predict that during the 21st century some grasslands will be in the N limitation stage where others will transition into the N saturation‐decline stage. The linear relationship between GHG sink strength and N load assumed by most studies can overestimate or underestimate predictions of the net GHG sink strength of grasslands depending on their N baseline status. The next generation of global change experiments should be designed at multiple N loads consistent with future Ndep rates to improve our empirical understanding and predictive ability. 相似文献
994.
As part of the process-characterization campaign of a candidate vaccine product, a recently developed class of three-level designs—definitive-screening designs—was employed to select a quadratic model that describes the effect of six input process parameters, including protein concentration, formaldehyde-to-protein ratio, lysine concentration, reaction duration, pH, and reaction temperature, on a formylation protein-crosslinking reaction. This design requires only 17 experimental runs. The resulting model was then used to simulate 10,000 runs that account for the variability in the inputs expected on manufacturing scale. The extent of protein polymerization was predicted to be within specifications for all simulated runs, demonstrating the robustness of the unit operation for subsequent process validation and future commercial manufacturing. 相似文献
995.
The Functional Quality of Soluble Recombinant Polypeptides Produced in Escherichia coli Is Defined by a Wide Conformational Spectrum 下载免费PDF全文
Mnica Martínez-Alonso Nuria Gonzlez-Montalbn Elena García-Fruits Antonio Villaverde 《Applied microbiology》2008,74(23):7431-7433
We have observed that a soluble recombinant green fluorescent protein produced in Escherichia coli occurs in a wide conformational spectrum. This results in differently fluorescent protein fractions in which morphologically diverse soluble aggregates abound. Therefore, the functional quality of soluble versions of aggregation-prone recombinant proteins is defined statistically rather than by the prevalence of a canonical native structure. 相似文献
996.
Luis M. Bedoya Amparo lvarez Mercedes Bermejo Nuria Gonzlez Manuela Beltrn Sonsoles Snchez-Palomino Sully M. Cruz Isabel Gaitn Esther del Olmo Ricardo Escarcena Pablo A. García Armando Cceres Arturo San Feliciano Jos Alcamí 《Phytomedicine》2008,15(6-7):520-524
Prevention methods to avoid transmission of pathogens, including HIV, are crucial in the control of infectious diseases, not only to block epidemic spread but to avoid long-term treatments leading to emergence of resistances and drug associated side effects. Together with vaccine development, the discovery of new virucidal agents represents a research priority in this setting. In the screening of new compounds with antiviral activity, three Guatemalan plant extracts from Justicia reptans, Neurolaena lobata and Pouteria viridis were evaluated with a classic antiviral assay and were found to inhibit HIV replication. This activity was corroborated by an original recombinant virus assay, leading us to perform a deeper study of the virucidal activity. Active fractions were non-toxic in vitro and also inhibited other enveloped viruses. Moreover, these fractions were able to inhibit the transfer of HIV from dendritic cells (DCs) to lymphocytes, that represents the main way of HIV spread in vivo. 相似文献
997.
Nuria A. Illán-Cabeza Rosario A. Vilaplana Ysmael Alvarez Khalid Akdi Sanae Kamah Francisco Hueso-Ureña Miguel Quirós Francisco González-Vílchez Miguel N. Moreno-Carretero 《Journal of biological inorganic chemistry》2005,10(8):924-934
The new complex formed by Cd(II) and the 1:2 Schiff-base-type ligand 2,6-bis[1-(4-amino-1,2,3,6-tetrahydro-1,3-dimethyl-2,6-dioxopyrimidin-5-yl)imino]ethylpyridine
(DAPDAAU) has been chemically and structurally characterized by X-ray diffraction: the ion Cd(II) is surrounded by six nitrogen
atoms from two DAPDAAU ligands which coordinates each one in a tridentate fashion through the pyridine ring (N1) and both
azomethine nitrogen atoms (N5). The interaction of the Cd(II) complex (compound I) with calf-thymus DNA as observed by circular
dichroism spectroscopy suggests the initial unwinding of the DNA double helix strongly depends on increasing incubation times
and metal-to-nucleic acid molar ratios. Electrophoretic experiments indicate that the cadmium complex induces cleavage of
the plasmid pBR322 DNA to give ulterior nicking and shortening of this molecule, as a result of the complex binding to DNA,
resulting in the conclusion that compound I behaves as a chemical nuclease. Cytotoxic activity of the Cd(II) complex against
selected different human cancer cell lines is specific and increases with increasing concentration of the metal compound;
this fact indicates the potential antitumor character of the complex. When the culture medium is supplemented with compound
I, a remarkable inhibition of the growing cell is observed, important cell degeneration appears before 48 h and abundant precipitates
are formed that correspond to cell residues and denatured proteins.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
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1000.
The potential of alleviated fishing pressure measures established at the Marine Natural Reserve of Cerbère-Banyuls to affect phenological characters of P. oceanica, the main canopy-forming seagrass, was studied. Our results show differences in some leaf parameters between meadows under fishing prohibition measures compared to those without. In addition shallow P. oceanica meadows inside MPAs had lower non-structural carbohydrate content, yet are able to maintain themselves and, moreover, with an increased density. On the other hand, sexual reproduction was reduced inside protected areas. 相似文献