共查询到20条相似文献,搜索用时 15 毫秒
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Marco A. B. Almeida Jader da C. Cardoso Edmilson dos Santos Daltro F. da Fonseca Laura L. Cruz Fernando J. C. Faraco Marilina A. Bercini Kátia C. Vettorello Mariana A. Porto Renate Mohrdieck Tani M. S. Ranieri Maria T. Schermann Alethéa F. Sperb Francisco Z. Paz Zenaida M. A. Nunes Alessandro P. M. Romano Zouraide G. Costa Silvana L. Gomes Brendan Flannery 《PLoS neglected tropical diseases》2014,8(3)
In Brazil, epizootics among New World monkey species may indicate circulation of yellow fever (YF) virus and provide early warning of risk to humans. Between 1999 and 2001, the southern Brazilian state of Rio Grande do Sul initiated surveillance for epizootics of YF in non-human primates to inform vaccination of human populations. Following a YF outbreak, we analyzed epizootic surveillance data and assessed YF vaccine coverage, timeliness of implementation of vaccination in unvaccinated human populations. From October 2008 through June 2009, circulation of YF virus was confirmed in 67 municipalities in Rio Grande do Sul State; vaccination was recommended in 23 (34%) prior to the outbreak and in 16 (24%) within two weeks of first epizootic report. In 28 (42%) municipalities, vaccination began more than two weeks after first epizootic report. Eleven (52%) of 21 laboratory-confirmed human YF cases occurred in two municipalities with delayed vaccination. By 2010, municipalities with confirmed YF epizootics reported higher vaccine coverage than other municipalities that began vaccination. In unvaccinated human populations timely response to epizootic events is critical to prevent human yellow fever cases. 相似文献
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Kenneth C. Catania 《Brain Cell Biology》2002,31(3-5):347-358
In the last decade improvements in the histological processing of cortical tissue in conjunction with the investigation of additional mammalian species in comparative brain studies has expanded the information available to guide theories of cortical organization. Here I review some of these recent findings in the somatosensory system with an emphasis on modules related to specializations of the peripheral sensory surface. The diversity of modular representations, or cortical “isomorphs” suggest that information from the sensory sheet guides many of the features of cortical maps and suggest that cortex is not constrained to form circular units in the form of a traditional cortical column. 相似文献
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Restoration should be a part of an overall strategy for national, regional and local land management, rather than an independent action. A hierarchically structured approach for restoration is examined by introducing actual policy and work for reestablishment of natural forest in Tokushima Prefecture, Shikoku, Japan. The goal set by Tokushima Prefectural Government is to increase the quality of biotope for indigenous plants and animals through increasing the area of natural and semi-natural vegetation and their connectivity. A networking map indicating high priority areas to be conserved or to be restored has been produced, using Natural Environment GIS provided by the Ministry of Environment of Japan. Having the estimated distribution of natural forests is helpful for selecting the targets for restoration, because natural forests have already disappeared from most regions due to land development. For reforestation at the cutover site, a method for designing work was developed. In order to select species and plan planting zones, ecotope types were identified both in natural forest as a reference and at the cutover site. A system for supplying indigenous seedlings was established. 相似文献
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Rebeca Droguett 《Experimental cell research》2010,316(15):2487-1639
Skeletal muscle differentiation is strongly inhibited by transforming growth factor type β (TGF-β), although muscle formation as well as regeneration normally occurs in an environment rich in this growth factor. In this study, we evaluated the role of intracellular regulatory Smads proteins as well as TGF-β-receptors (TGF-β-Rs) during skeletal muscle differentiation. We found a decrease of TGF-β signaling during differentiation. This phenomenon is explained by a decline in the levels of the regulatory proteins Smad-2, -3, and -4, a decrease in the phosphorylation of Smad-2 and lost of nuclear translocation of Smad-3 and -4 in response to TGF-β. No change in the levels and inhibitory function of Smad-7 was observed. In contrast, we found that TGF-β-R type I (TGF-β-RI) and type II (TGF-β-RII) increased on the cell surface during skeletal muscle differentiation. To analyze the direct role of the serine/threonine kinase activities of TGF-β-Rs, we used the specific inhibitor SB 431542 and the dominant-negative form of TGF-β-RII lacking the cytoplasmic domain. The TGF-β-Rs were important for successful muscle formation, determined by the induction of myogenin, creatine kinase activity, and myosin. Silencing of Smad-2/3 expression by specific siRNA treatments accelerated myogenin, myosin expression, and myotube formation; although when SB 431542 was present inhibition in myosin induction and myotube formation was observed, suggesting that these last steps of skeletal muscle differentiation require active TGF-β-Rs. These results suggest that both down-regulation of Smad regulatory proteins and cell signaling through the TGF-β receptors independent of Smad proteins are essential for skeletal muscle differentiation. 相似文献
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Riparian plants on mine runoff in Zimapan,Hidalgo, Mexico: Useful for phytoremediation? 总被引:1,自引:0,他引:1
Eréndira Carmona-Chit Ma.del Carmen A. González-Chávez Heike Vibrans Laura Yáñez-Espinosa Adriana Delgado-Alvarado 《International journal of phytoremediation》2016,18(9):861-868
Dispersion and runoff of mine tailings have serious implications for human and ecosystem health in the surroundings of mines. Water, soils and plants were sampled in transects perpendicular to the Santiago stream in Zimapan, Hidalgo, which receives runoff sediments from two acidic and one alkaline mine tailing. Concentrations of potentially toxic elements (PTE) were measured in water, soils (rhizosphere and non-rhizosphere) and plants. Using diethylenetriaminepentaacetic acid (DTPA) extractable concentrations of Cu, Zn, Ni, Cd and Pb in rhizosphere soil, the bioconcentration and translocation factors were calculated. Ruderal annuals formed the principal element of the herbaceous vegetation. Accumulation was the most frequent strategy to deal with high concentrations of Zn, Cu, Ni, Cd and Pb. The order of concentration in plant tissue was Zn>Pb>Cu>Ni>Cd. Most plants contained concentrations of PTE considered as phytotoxic and behaved as metal tolerant species. Rorippa nasturtium-aquaticum accumulated particularly high concentrations of Cu. Parietaria pensylvanica and Commelina diffusa, common tropical weeds, behaved as Zn hyperaccumulators and should be studied further. 相似文献
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Pollination Syndromes in Mediterranean Orchids—Implications for Speciation,Taxonomy and Conservation
The Mediterranean flora is spectacularly rich in orchid species that have evolved remarkable adaptations to their environment.
Orchids have complex and delicate interactions with their pollinators, which makes them particularly prone to local extinction.
Conservation actions should be encouraged for a range of endangered Mediterranean orchid species, but the current taxonomic
confusion in several genera and the apparent disagreement among orchid taxonomists make the situation particularly confusing
from a conservation perspective. In this review, we document how the different pollination syndromes of Mediterranean orchids
(nectar reward, shelter offering, food deception and sexual deception) can have a profound impact on the type of reproductive
barriers among species, on floral phenotypic variation as we perceive it, on potentially related processes of species sorting
and extinction and, consequently, should have a strong influence on the related conservation management programs. We also
highlight that the majority of Mediterranean orchids are pollinated by specialised bees often occupying otherwise narrow ecological
niches (e.g. pollen specialisation, brood cell parasites, specific nesting site). This condition makes the orchid-pollinator
interactions very fragile and several orchid species prone to local extinction. We illustrate this phenomenon by a selection
of case studies that show how the adequate integration of the ecological requirements/traits of the orchids and their associated
pollinators into conservation actions could help protect endangered species and ensure the sustainability of the often complex
local pollination web. 相似文献
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J Lee T Nakagiri T Oto M Harada E Morii Y Shintani M Inoue Y Iwakura S Miyoshi M Okumura T Hirano M Murakami 《Journal of immunology (Baltimore, Md. : 1950)》2012,189(4):1928-1936
The IL-6-amplifier first was discovered as a synergistic activation mechanism for NF-κB/STAT3 in type 1 collagen(+) cells. This process is marked by the hyperinduction of chemokines and subsequent local inflammation that leads to autoimmune diseases. In this study, we show that IL-6 amplifier activation in grafts plays important roles in allogeneic graft rejection by using a tracheal heterotopic transplantation model that includes bronchiolitis obliterans, a pathological marker for chronic rejection. IL-6, epidermal growth factor, and IFN-γ all stimulate IL-6 amplifier activation, whereas CCL2, a chemotactic factor for Th1 cells, was one of the amplifier's main targets. Interestingly, IFN-γ hyperinduced CCL2 in type 1 collagen(+) cells via the IL-6 amplifier at least in vitro. In addition, we detected IL-6, CCL2, phospho-STAT3, and phospho-NF-κB in epithelial type 1 collagen(+) cells of allogeneic tracheal grafts. These results show that IL-6 amplifier activation in grafts plays a critical role for graft rejection responses after allogeneic transplantation, including chronic rejection. From these results, we consider whether the IL-6 amplifier in grafts might be a valuable therapeutic target for the prevention of transplant rejection, including chronic rejection. 相似文献
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Sonia Graham 《Wetlands Ecology and Management》2009,17(4):303-316
In Australia and many countries worldwide environmental flows are becoming an increasingly popular tool for reducing the negative
impacts of river regulation. However, there are many factors that restrict the effectiveness of these flows such as thermal
pollution, existing physical infrastructure and the limited volume of water available. Since environmental flows result in
reduced water allocations for irrigators, the aim of the present study was to investigate whether irrigators’ attitudes towards
environmental flows for wetlands are influenced by the effectiveness of these flows. Three focus groups were used to engage
with farmers in the Murrumbidgee Catchment, eastern Australia. A simulation model of the Murrumbidgee River was created to
provide focus groups with a tool for examining the effectiveness of wetland-watering releases and exploring alternative management
scenarios. The results showed that participants support the principle of environmental flows for wetlands. However, they believed
that the flows could be more effective if the restrictions imposed by physical infrastructure were removed. They also suggested
that the volume of translucency releases should be lowered, as these flows reduce the amount of water available for wetlands
and lower early season allocations for general-security water users. The participants provided numerous suggestions for altering
the management of water resources so that both the Mid Murrumbidgee Wetlands and farmers would benefit.
相似文献
Sonia GrahamEmail: |
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It has been repeatedly suggested that primates trade social services for fitness benefits in their relationships with the opposite sex. We tested this proposal in a colony of captive chimpanzees, Pan troglodytes, by examining behavioural data on grooming, agonistic support and food sharing in relation to genetically established paternity. We found no support for the notion of trade. First, males did not sire more offspring with females that they actively groomed more frequently, that they supported more often or with which they shared food more frequently. Correspondingly, females did not give birth to more offspring sired by males from which they received more services. Second, males that showed more affiliative behaviour towards females in general did not sire more progeny. Furthermore, females did not bear more offspring sired by males to which they themselves directed more sociopositive behaviour. Results from this captive colony are compatible with those reported for chimpanzees under natural conditions. Copyright 1999 The Association for the Study of Animal Behaviour. 相似文献
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A birth-death process is a continuous-time Markov chain that counts the number of particles in a system over time. In the general process with n current particles, a new particle is born with instantaneous rate λ(n) and a particle dies with instantaneous rate μ(n). Currently no robust and efficient method exists to evaluate the finite-time transition probabilities in a general birth-death process with arbitrary birth and death rates. In this paper, we first revisit the theory of continued fractions to obtain expressions for the Laplace transforms of these transition probabilities and make explicit an important derivation connecting transition probabilities and continued fractions. We then develop an efficient algorithm for computing these probabilities that analyzes the error associated with approximations in the method. We demonstrate that this error-controlled method agrees with known solutions and outperforms previous approaches to computing these probabilities. Finally, we apply our novel method to several important problems in ecology, evolution, and genetics. 相似文献
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《Ethnic and racial studies》2012,35(8):1392-1408
Abstract Despite increasing demand from policymakers and academics alike, effective policies on ethnic data collection for social inclusion purposes are still absent in most of Europe. This paper proposes to explain the failure to produce these policies by the coexistence of and tensions among contradictory frames on ethnic counting. An in-depth analysis of Hungarian policies reveals that three mutually inconsistent policy frames connect ethnic counting to ethnic diversity in many different ways. These frames are group self-determination, individual rights, and social inclusion. This paper illustrates the tensions among the three through a discussion of two core but divisive aspects of collecting ethnic statistics: defining ethnic classifications for counting and defining membership in ethnic groups for policy purposes. Tensions among the three result in inconsistent and inefficient policies of ethnic counting. 相似文献
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Juliane Struve Kai Lorenzen Julia Blanchard Luca B?rger Nils Bunnefeld Charles Edwards Joaquín Hortal Alec MacCall Jason Matthiopoulos Bram Van Moorter Arpat Ozgul Fran?ois Royer Navinder Singh Chris Yesson Rodolphe Bernard 《Biology letters》2010,6(5):575-578
The workshop ‘Spatial models in animal ecology, management and conservation’ held at Silwood Park (UK), 9–11 March 2010, aimed to synthesize recent progress in modelling the spatial dynamics of individuals, populations and species ranges and to provide directions for research. It brought together marine and terrestrial researchers working on spatial models at different levels of organization, using empirical as well as theory-driven approaches. Different approaches, temporal and spatial scales, and practical constraints predominate at different levels of organization and in different environments. However, there are theoretical concepts and specific methods that can fruitfully be transferred across levels and systems, including: habitat suitability characterization, movement rules, and ways of estimating uncertainty. 相似文献
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Phylogeography of Fischer’s blue,Tongeia fischeri,in Japan: Evidence for introgressive hybridization
Ekgachai Jeratthitikul Takehiro Hara Masaya Yago Tateo Itoh Min Wang Shin-ichi Usami Tsutomu Hikida 《Molecular phylogenetics and evolution》2013,66(1):316-326
The widespread lycaenid butterfly Tongeia fischeri is distributed from eastern Europe to northeastern Asia and represented by three geographically isolated populations in Japan. In order to clarify the phylogeographic history of the species, we used sequences of three mitochondrial (COI, Cyt b and ND5) and two nuclear (Rpl5 and Ldh) genes of 207 individuals collected from 55 sites throughout Japan and five sites on the Asian continent. Phylogenetic trees and the median-joining network revealed six evolutionary mitochondrial haplotype clades, which corresponded to the geographic distribution of the species. Common ancestors of Japanese T. fischeri might have come to Japan during the mid-Pleistocene by multiple dispersals of continental populations, probably via a land bridge or narrow channel between western Japan and the Korean Peninsula. The geographical patterns of variation of mitochondrial and nuclear markers are discordant in northeastern Kyushu, possibly as a result of introgressive hybridization during the ancient contact between the Kyushu and Shikoku populations in the last glacial maximum. The phylogeographic pattern of T. fischeri in Japan are probably related to the geological history, Pleistocene climatic oscillations and distribution of the host plant. 相似文献
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Pioglitazone, a synthetic ligand for PPARγ, induces apoptosis in RB-deficient human colorectal cancer cells 总被引:1,自引:0,他引:1
Lee CJ Han JS Seo CY Park TH Kwon HC Jeong JS Kim IH Yun J Bae YS Kwak JY Park JI 《Apoptosis : an international journal on programmed cell death》2006,11(3):401-411
No published data are available about the expression of peroxisome proliferator-activated receptor γ (PPARγ) and the role
of PPARγ in retinoblastoma protein (RB)-deficient human colorectal cancer (CRC) cells (SNU-C4 and SNU-C2A). Our aim was to
investigate whether PPARγ is expressed in SNU-C4 and SNU-C2A cells and to elucidate possible molecular mechanisms underlying
the effect of pioglitazone, a synthetic ligand for PPARγ, on cell growth in these cell lines. RT-PCR and Western blot analysis
showed that both human CRC cell lines expressed PPARγ mRNA and protein. Pioglitazone inhibited the cell growth of both cell
lines through G2/M phase block and apoptosis. In addition, pioglitazone caused a down-regulation of the X chromosome-linked
inhibitor of apoptosis (XIAP), Bcl-2, and cyclooxygenase-2 (COX-2) under conditions leading to PPARγ down-regulation. These
results suggest that pioglitazone may have therapeutic relevance or significance in the treatment of human CRC, and the down-regulation
of XIAP, Bcl-2, and COX-2 may contribute to pioglitazone-induced apoptosis in these and other RB-deficient cell lines and
tumors. 相似文献