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991.
Félix M. Medina Elsa Bonnaud Eric Vidal Bernie R. Tershy Erika S. Zavaleta C. Josh Donlan Bradford S. Keitt Matthieu Le Corre Sarah V. Horwath Manuel Nogales 《Global Change Biology》2011,17(11):3503-3510
Cats are generalist predators that have been widely introduced to the world's ~179 000 islands. Once introduced to islands, cats prey on a variety of native species many of which lack evolved defenses against mammalian predators and can suffer severe population declines and even extinction. As islands house a disproportionate share of terrestrial biodiversity, the impacts of invasive cats on islands may have significant biodiversity impacts. Much of this threatened biodiversity can be protected by eradicating cats from islands. Information on the relative impacts of cats on different native species in different types of island ecosystems can increase the efficiency of this conservation tool. We reviewed feral cat impacts on native island vertebrates. Impacts of feral cats on vertebrates have been reported from at least 120 different islands on at least 175 vertebrates (25 reptiles, 123 birds, and 27 mammals), many of which are listed by the International Union for the Conservation of Nature. A meta‐analysis suggests that cat impacts were greatest on endemic species, particularly mammals and greater when non‐native prey species were also introduced. Feral cats on islands are responsible for at least 14% global bird, mammal, and reptile extinctions and are the principal threat to almost 8% of critically endangered birds, mammals, and reptiles. 相似文献
992.
Emerging diversity within chrysophytes, choanoflagellates and bicosoecids based on molecular surveys
In recent years, a substantial amount of data on aquatic protists has been obtained from culture-independent molecular approaches, unveiling a large diversity and the existence of new lineages. However, sequences affiliated with minor groups (in terms of clonal abundance) have often been under-analyzed, and this hides a potentially relevant source of phylogenetic information. Here we have searched public databases for 18S rDNA sequences of chrysophytes, choanoflagellates and bicosoecids retrieved from molecular surveys of protists. These three groups are often considered to account for most of the heterotrophic flagellates, an important functional component in microbial food webs. They represented a significant fraction of clones in freshwater studies, whereas their relative clonal abundance was low in marine studies. The novelty displayed by this dataset was notable. Most environmental sequences were distant to sequences of cultured organisms, indicating a significant bias in the representation of taxa in culture. Moreover, they were often distant to sequences from other molecular surveys, suggesting an insufficient sequencing effort to characterize the in situ diversity of these groups. Phylogenetic trees with complete sequences present the most accurate representation of the diversity of these groups, with the emergence of several new clades formed exclusively by environmental sequences. Exhaustive data mining in sequence databases allowed the identification of new diversity hidden inside chrysophytes, choanoflagellates and bicosoecids. 相似文献
993.
A variety of neurological diseases including Huntington's disease (HD), Alzheimer's disease and Parkinson's disease share common neuropathology, primarily featuring the presence of abnormal protein inclusions containing specific misfolded proteins. Mutations leading to expansion of a poly-glutamine track in Huntingtin cause HD, and trigger its misfolding and aggregation. Recent evidence indicates that alterations in the secretory pathway, in particular the endoplasmic reticulum (ER), are emerging features of HD. Although it is not clear how cytoplasmic/nuclear located mutant Huntingtin alters the function of the ER, several reports indicate that mutant Huntingtin affects many essential processes related to the secretory pathway, including inhibition of ER-associated degradation, altered ER/Golgi vesicular trafficking and axonal transport, disrupted autophagy and abnormal ER calcium homeostasis. All these alterations are predicted to have a common pathological outcome associated to disturbance of protein folding and maturation pathways at the ER, generating chronic ER stress and neuronal dysfunction. Here, we review recent evidence involving ER stress in HD pathogenesis and discuss possible therapeutic strategies to target organelle function in the context of disease. 相似文献
994.
Faivre L Gomo C Mir O Taieb F Schoemann-Thomas A Ropert S Vidal M Dusser D Dauphin A Goldwasser F Blanchet B 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(23):2345-2350
Gefitinib and erlotinib are two oral tyrosine kinase inhibitors (TKI) approved for the treatment of advanced non-small cell lung cancer (NSCLC). Published methods for simultaneous analysis of erlotinib and gefitinib in plasma are exclusively based on mass spectrometry. The purpose of this study was to develop a simple and sensitive HPLC-UV method to simultaneously quantify these two TKI in plasma. Following liquid-liquid extraction, gefitinib, erlotinib and sorafenib (internal standard), were separated with gradient elution (on a C8+ Satisfaction(?) using a mobile phase of acetonitrile/20mM ammonium acetate pH 4.5). Samples were eluted at a flow rate of 0.4 ml/min throughout the 15-min run. Dual UV wavelength mode was used, with gefitinib and erlotinib monitored at 331 nm, and sorafenib at 249 nm. The calibration was linear in the range 20-1000 ng/ml and 80-4000 ng/ml for gefitinib and erlotinib, respectively. Inter- and intra-day imprecision were less than 7.2% and 7.6% for gefitinib and erlotinib, respectively. This analytical method was successfully applied to assess the steady state plasma exposure to these TKI in NSCLC patients. This simple, sensitive, accurate and cost-effective method can be used in routine clinical practice to monitor gefitinib or erlotinib concentrations in plasma from NSCLC patients. 相似文献
995.
The synthesis of RNA molecules carrying lipids at their 3'-termini and 5'-termini is reported. These conjugates were fully characterized by MALDI-TOF mass spectrometry and HPLC chromatography. The ability of these conjugates to silence gene expression was evaluated in the inhibition of the tumor necrosis factor. All the lipid-siRNA derivatives were compatible with RNA interference machinery if transfected with oligofectamine. In the absence of a transfection agent, some lipid-siRNA derivatives can exert a slight reduction of gene expression. 相似文献
996.
Emmanuel Serrano Jose Enrique Granados Mathieu Sarasa Francisco Jose González Paulino Fandos Ramon C. Soriguer Jesus M. Pérez 《European Journal of Wildlife Research》2011,57(1):45-55
We studied the factors that determined kidney fat stores (KFs) and kidney stores (Ks)—defined as the residuals from the linear
regression of kidney mass and kidney fat, respectively, on body weight—in 463 Iberian wild goats (Capra pyrenaica) from the Sierra Nevada (southern Spain). Despite the fact that body stores in both sexes were highest during the warmest
months of the year and lowest during the coldest months when food resources are limited, the observed pattern was sex- and
age-dependent. The KFs of male goats fell more than those of females in winter, and the yearlings of both sexes needed one
season more than young or adults to restore their KFs. Goats of all age classes showed the same seasonal patterns in their
Ks, although Ks were lower in females than in males throughout the yearly cycle. In addition, we found strong delayed effects
of both snowfalls and population density on body stores, and in years with a lot of snow, goats' KFs reached their lowest
levels in the current winter–spring, but the highest in the following summers and autumns. This pattern was less noticeable
in the Ks. Population density negatively affected the body stores of wild goats, especially in winter, and the amount of snow
fallen in the year of birth (cohort effect) did not seem to influence the body stores in our data set. In addition, we assessed
the accuracy of the residuals from the regression between body size and body mass for monitoring body condition of live wild
goats and concluded that, although it poorly indicates fat stores, it could be used as a general proxy of body condition.
Finally, we discuss the expected effects of climate warming on body stores in this Mediterranean Caprinae species. 相似文献
997.
Invasion and metastasis are the most deadly hallmarks of cancer.Once a cancer has acquired the ability to colonize new sites in the body it becomes dramatically more difficult to treat.This has made it a focus of much of cancer research.The humble fruit fly,Drosophila melanogaster,has despite its relative simplicity,made significant contributions to the understanding of tumor progression.In this review we outline and highlight those with an emphasis on modeling the genetic and epigenetic changes required for invasion and metastasis.We will revisit the early years of cancer modeling in Drosophila where the first parallels were drawn between Drosophila and vertebrate neoplasms and highlight recent advances using genetic screens and interactions with the epithelial microenvironment and innate immune system.We focus on the power and limitations of current fly models of metastasis. 相似文献
998.
Alterations in the photoactivation pathway of rhodopsin mutants associated with retinitis pigmentosa
The visual photoreceptor rhodopsin undergoes a series of conformational changes upon light activation, eventually leading to the active metarhodopsin II conformation, which is able to bind and activate the G-protein, transducin. We have previously shown that mutant rhodopsins G51V and G89D, associated with retinitis pigmentosa, present photobleaching patterns characterized by the formation of altered photointermediates whose nature remained obscure. Our current detailed UV-visible spectroscopic analysis, together with functional characterization, indicate that these mutations influence the relative stability of the different metarhodopsin photointermediates by altering their equilibria and maintaining the receptor in a nonfunctional light-induced conformation that may be toxic to photoreceptor cells. We propose that G51V and G89D shift the equilibrium from metarhodopsin I towards an intermediate, recently named as metarhodopsin Ib, proposed to interact with transducin without activating it. This may be one of the causes contributing to the molecular mechanisms underlying cell death associated with some retinitis pigmentosa mutations. 相似文献
999.
Despite the ecological importance of marine pico-size eukaryotes, the study of their in situ diversity using molecular tools started just a few years ago. These studies have revealed that marine picoeukaryotes are very diverse and include many novel taxa. However, the amount and structure of their phylogenetic diversity and the extent of their sequence novelty still remains poorly known, as a systematic analysis has been seldom attempted. In this study, we use a coherent and carefully curated data set of 500 published 18S ribosomal DNA sequences to quantify the diversity and novelty patterns of picoeukaryotes in the Indian Ocean. Our phylogenetic tree showed many distant lineages. We grouped sequences in OTUs (operational taxonomic units) at discrete values delineated by pair-wise Jukes–Cantor (JC) distances and tree patristic distances. At a distance of 0.01, the number of OTUs observed (237/242; using JC or patristic distances, respectively) was half the number of sequences analyzed, indicating the existence of microdiverse clusters of highly related sequences. At this distance level, we estimated 600–800 OTUs using several statistical methods. The number of OTUs observed was still substantial at higher distances (39/82 at 0.20 distance) suggesting a large diversity at high-taxonomic ranks. Most sequences were related to marine clones from other sites and many were distant to cultured organisms, highlighting the huge culturing gap within protists. The novelty analysis indicated the putative presence of pseudogenes and of truly novel high-rank phylogenetic lineages. The identified diversity and novelty patterns among marine picoeukaryotes are of great importance for understanding and interpreting their ecology and evolution. 相似文献
1000.