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31.
32.
Late Quaternary climate change,relict populations and present‐day refugia in the northern Atacama Desert: a case study from Quebrada La Higuera (18° S) 下载免费PDF全文
33.
Halobacterial megaplasmids are negatively supercoiled 总被引:1,自引:0,他引:1
Purificación López-García Josefa Antón Jose Pascua Abad Ricardo Amils 《Molecular microbiology》1994,11(3):421-427
Several covalently closed circular halobacterial megaplasmids (up to more than 500 kb) from different strains of Halolerax mediterranei, have been resolved by orthogonal-field alternating gel electro-phoresis (OFAGE). These molecules seem to be negatively supercoiled in vivo, as deduced from the effect of intercalating agents affecting their topology and, therefore, their electrophoretic mobility. It has also been demonstrated that the topolsomerase II Inhibitor novobiocin affects the native topological state of halobacterial megaplasmids impeding their migration in OFAGE under standard conditions for resolution of large supercoiled molecules. 相似文献
34.
Juan A. Godoy Macarena S. Arrázola Daniela Ordenes Carmen Silva-Alvarez Nady Braidy Nibaldo C. Inestrosa 《The Journal of biological chemistry》2014,289(52):36179-36193
The Wnt signaling pathway plays an important role in developmental processes, including embryonic patterning, cell specification, and cell polarity. Wnt components participate in the development of the central nervous system, and growing evidence indicates that this pathway also regulates the function of the adult nervous system. In this study, we report that Wnt-5a, a noncanonical Wnt ligand, is a potent activator of mitochondrial dynamics and induces acute fission and fusion events in the mitochondria of rat hippocampal neurons. The effect of Wnt-5a was inhibited in the presence of sFRP, a Wnt scavenger. Similarly, the canonical Wnt-3a ligand had no effect on mitochondrial fission-fusion events, suggesting that this effect is specific for Wnt-5a alone. We also show that the Wnt-5a effects on mitochondrial dynamics occur with an increase in both intracellular and mitochondrial calcium (Ca2+), which was correlated with an increased phosphorylation of Drp1(Ser-616) and a decrease of Ser-637 phosphorylation, both indicators of mitochondrial dynamics. Electron microscope analysis of hippocampal tissues in the CA1 region showed an increase in the number of mitochondria present in the postsynaptic region, and this finding correlated with a change in mitochondrial morphology. We conclude that Wnt-5a/Ca2+ signaling regulates the mitochondrial fission-fusion process in hippocampal neurons, a feature that might help to further understand the role of Wnt-related pathologies, including neurodegenerative diseases associated with mitochondrial dysfunction, and represents a potentially important link between impaired metabolic function and degenerative disorders. 相似文献
35.
Wladimir J. Alonso Maia A. Rabaa Ricardo Giglio Mark A. Miller Cynthia Schuck-Paim 《PloS one》2015,10(10)
Existing modeling approaches are divided between a focus on the constitutive (micro) elements of systems or on higher (macro) organization levels. Micro-level models enable consideration of individual histories and interactions, but can be unstable and subject to cumulative errors. Macro-level models focus on average population properties, but may hide relevant heterogeneity at the micro-scale. We present a framework that integrates both approaches through the use of temporally structured matrices that can take large numbers of variables into account. Matrices are composed of several bidimensional (time×age) grids, each representing a state (e.g. physiological, immunological, socio-demographic). Time and age are primary indices linking grids. These matrices preserve the entire history of all population strata and enable the use of historical events, parameters and states dynamically in the modeling process. This framework is applicable across fields, but particularly suitable to simulate the impact of alternative immunization policies. We demonstrate the framework by examining alternative strategies to accelerate measles elimination in 15 developing countries. The model recaptured long-endorsed policies in measles control, showing that where a single routine measles-containing vaccine is employed with low coverage, any improvement in coverage is more effective than a second dose. It also identified an opportunity to save thousands of lives in India at attractively low costs through the implementation of supplementary immunization campaigns. The flexibility of the approach presented enables estimating the effectiveness of different immunization policies in highly complex contexts involving multiple and historical influences from different hierarchical levels. 相似文献
36.
37.
Social relations involve both face-to-face interaction as well as telecommunications. We can observe the geography of phone calls and of the mobility of cell phones in space. These two phenomena can be described as networks of connections between different points in space. We use a dataset that includes billions of phone calls made in Colombia during a six-month period. We draw the two networks and find that the call-based network resembles a higher order aggregation of the mobility network and that both are isomorphic except for a higher spatial decay coefficient of the mobility network relative to the call-based network: when we discount distance effects on the call connections with the same decay observed for mobility connections, the two networks are virtually indistinguishable. 相似文献
38.
AbstractSilk sericin is a globular protein whose resistance against fouling is important for applications in biomaterials and water-purification membranes. Here it is shown how sericin generates a water-exclusion zone that may facilitate antifouling behavior. Negatively charged microspheres were used to mimic the surface charge and hydrophobic domains in bacteria. Immersed in water, regenerated silk sericin formed a 100-µm-sized exclusion zone (for micron-size foulants), along with a proton gradient with a decrease of >2?pH-units. Thus, when in contact with sericin, water molecules near the surface restructure to form a physical exclusionary barrier that might prevent biofouling. The decreased pH turns the aqueous medium unviable for neutrophilic bacteria. Therefore, resistance to biofouling seems explainable, among other factors, on the basis of water-exclusionary phenomena. Furthermore, sericin may play a role in triggering the fibroin assembly process by lowering the pH to the required value. 相似文献
39.
Maurício Luiz Vilela Daniela de Pita-Pereira Carina Graser Azevedo Rodrigo Espíndola Godoy Constan?a Britto Elizabeth Ferreira Rangel 《Memórias do Instituto Oswaldo Cruz》2013,108(5):578-585
Phlebotomine sandflies were captured in rural settlement and periurban
areas of the municipality of Guaraí in the state of Tocantins (TO), an endemic
area of American cutaneous leishmaniasis (ACL). Forty-three phlebotomine species
were identified, nine of which have already been recognised as ACL vectors.
Eleven species were recorded for the first time in TO. Nyssomyia
whitmani was the most abundant species, followed by
Evandromyia bourrouli, Nyssomyia antunesi
and Psychodopygus complexus. The Shannon-Wiener diversity index
and the evenness index were higher in the rural settlement area than in the
periurban area. The evaluation of different ecotopes within the rural area
showed the highest frequencies of Ev. bourrouli and Ny.
antunesi in chicken coops, whereas Ny. whitmani
predominated in this ecotope in the periurban area. In the rural settlement
area, Ev. bourrouli was the most frequently captured species in
automatic light traps and Ps. complexus was the most prevalent
in Shannon trap captures. The rural settlement environment exhibited greater
phlebotomine biodiversity than the periurban area. Ps.
complexus and Psychodopygus ayrozai naturally
infected with Leishmania (Viannia) braziliensis were
identified. The data identified Ny. whitmani as a potential ACL
vector in the periurban area, whereas Ps. complexus was more
prevalent in the rural environment associated with settlements. 相似文献
40.
Carolina David Wiener Karen Jansen Gabriele Ghisleni Manuella Pinto Kaster Luciano Dias de Mattos Souza Diogo Rizzato Lara Luiz Valmor Portela Ricardo Azevedo da Silva Jean Pierre Oses 《Neurochemical research》2013,38(7):1394-1398
Several biological factors have been recently related with major depression and bipolar disorder. The aim of our paper was to investigate the peripheral levels of the protein neuronal specific enolase (NSE), a putative marker of neuronal damage, comparing patients with major depressive disorder and bipolar disorder to control subjects. This is a case–control study nested in a cross-sectional population-based survey. Psychopathology screen was performed using the Mini-International Neuropsychiatric Interview 5.0 and blood samples were collected from 108 young adults. Three groups were selected, 36 healthy controls, 36 subjects with major depression disorder and 36 subjects with bipolar disorder. Serum levels of NSE significantly decreased (p = 0.002) in major depression disorder (2.19 ± 1.78 ng/mL) and bipolar disorder subjects (2.53 ± 2.61 ng/mL) compared to the control group (3.55 ± 2.19 ng/mL). In conclusion, peripheral neuronal specific enolase may be a useful marker drug-naïve major depression disorder and bipolar disorder, but its pathophysiological significance and response to treatment should be further investigated. 相似文献