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91.
Raxworthy CJ Martinez-Meyer E Horning N Nussbaum RA Schneider GE Ortega-Huerta MA Townsend Peterson A 《Nature》2003,426(6968):837-841
Despite the importance of tropical biodiversity, informative species distributional data are seldom available for biogeographical study or setting conservation priorities. Modelling ecological niche distributions of species offers a potential solution; however, the utility of old locality data from museums, and of more recent remotely sensed satellite data, remains poorly explored, especially for rapidly changing tropical landscapes. Using 29 modern data sets of environmental land coverage and 621 chameleon occurrence localities from Madagascar (historical and recent), here we demonstrate a significant ability of our niche models in predicting species distribution. At 11 recently inventoried sites, highest predictive success (85.1%) was obtained for models based only on modern occurrence data (74.7% and 82.8% predictive success, respectively, for pre-1978 and all data combined). Notably, these models also identified three intersecting areas of over-prediction that recently yielded seven chameleon species new to science. We conclude that ecological niche modelling using recent locality records and readily available environmental coverage data provides informative biogeographical data for poorly known tropical landscapes, and offers innovative potential for the discovery of unknown distributional areas and unknown species. 相似文献
92.
de Lucas M Davière JM Rodríguez-Falcón M Pontin M Iglesias-Pedraz JM Lorrain S Fankhauser C Blázquez MA Titarenko E Prat S 《Nature》2008,451(7177):480-484
93.
The d-enantiomers of amino acids have been thought to have relatively minor functions in biological processes. While l-amino acids clearly predominate in nature, d-amino acids are sometimes found in proteins that are not synthesized by ribosomes, and d-Ala and d-Glu are routinely found in the peptidoglycan cell wall of bacteria. Here, we review recent findings showing that d-amino acids have previously unappreciated regulatory roles in the bacterial kingdom. Many diverse bacterial phyla synthesize
and release d-amino acids, including d-Met and d-Leu, which were not previously known to be made. These noncanonical d-amino acids regulate cell wall remodeling in stationary phase and cause biofilm dispersal in aging bacterial communities.
Elucidating the mechanisms by which d-amino acids govern cell wall remodeling and biofilm disassembly will undoubtedly reveal new paradigms for understanding how
extracytoplasmic processes are regulated as well as lead to development of novel therapeutics. 相似文献
94.
Yesica R. Nievas Veronica M. Coceres Victor Midlej Wanderley de Souza Marlene Benchimol Antonio Pereira-Neves Ajay A. Vashisht James A. Wohlschlegel Patricia J. Johnson Natalia de Miguel 《Cellular and molecular life sciences : CMLS》2018,75(12):2211-2226
Trichomonas vaginalis is a common sexually transmitted parasite that colonizes the human urogenital tract, where it remains extracellular and adheres to epithelial cells. Infections range from asymptomatic to highly inflammatory, depending on the host and the parasite strain. Despite the serious consequences associated with trichomoniasis disease, little is known about parasite or host factors involved in attachment of the parasite-to-host epithelial cells. Here, we report the identification of microvesicle-like structures (MVs) released by T. vaginalis. MVs are considered universal transport vehicles for intercellular communication as they can incorporate peptides, proteins, lipids, miRNA, and mRNA, all of which can be transferred to target cells through receptor–ligand interactions, fusion with the cell membrane, and delivery of a functional cargo to the cytoplasm of the target cell. In the present study, we demonstrated that T. vaginalis release MVs from the plasma and the flagellar membranes of the parasite. We performed proteomic profiling of these structures demonstrating that they possess physical characteristics similar to mammalian extracellular vesicles and might be selectively charged with specific protein content. In addition, we demonstrated that viable T. vaginalis parasites release large vesicles (LVs), membrane structures larger than 1 µm that are able to interact with other parasites and with the host cell. Finally, we show that both populations of vesicles present on the surface of T vaginalis are induced in the presence of host cells, consistent with a role in modulating cell interactions. 相似文献
95.
M Krauthammer Y Kong BH Ha P Evans A Bacchiocchi JP McCusker E Cheng MJ Davis G Goh M Choi S Ariyan D Narayan K Dutton-Regester A Capatana EC Holman M Bosenberg M Sznol HM Kluger DE Brash DF Stern MA Materin RS Lo S Mane S Ma KK Kidd NK Hayward RP Lifton J Schlessinger TJ Boggon R Halaban 《Nature genetics》2012,44(9):1006-1014
We characterized the mutational landscape of melanoma, the form of skin cancer with the highest mortality rate, by sequencing the exomes of 147 melanomas. Sun-exposed melanomas had markedly more ultraviolet (UV)-like C>T somatic mutations compared to sun-shielded acral, mucosal and uveal melanomas. Among the newly identified cancer genes was PPP6C, encoding a serine/threonine phosphatase, which harbored mutations that clustered in the active site in 12% of sun-exposed melanomas, exclusively in tumors with mutations in BRAF or NRAS. Notably, we identified a recurrent UV-signature, an activating mutation in RAC1 in 9.2% of sun-exposed melanomas. This activating mutation, the third most frequent in our cohort of sun-exposed melanoma after those of BRAF and NRAS, changes Pro29 to serine (RAC1(P29S)) in the highly conserved switch I domain. Crystal structures, and biochemical and functional studies of RAC1(P29S) showed that the alteration releases the conformational restraint conferred by the conserved proline, causes an increased binding of the protein to downstream effectors, and promotes melanocyte proliferation and migration. These findings raise the possibility that pharmacological inhibition of downstream effectors of RAC1 signaling could be of therapeutic benefit. 相似文献
96.
Quesada V Conde L Villamor N Ordóñez GR Jares P Bassaganyas L Ramsay AJ Beà S Pinyol M Martínez-Trillos A López-Guerra M Colomer D Navarro A Baumann T Aymerich M Rozman M Delgado J Giné E Hernández JM González-Díaz M Puente DA Velasco G Freije JM Tubío JM Royo R Gelpí JL Orozco M Pisano DG Zamora J Vázquez M Valencia A Himmelbauer H Bayés M Heath S Gut M Gut I Estivill X López-Guillermo A Puente XS Campo E López-Otín C 《Nature genetics》2012,44(1):47-52
Here we perform whole-exome sequencing of samples from 105 individuals with chronic lymphocytic leukemia (CLL), the most frequent leukemia in adults in Western countries. We found 1,246 somatic mutations potentially affecting gene function and identified 78 genes with predicted functional alterations in more than one tumor sample. Among these genes, SF3B1, encoding a subunit of the spliceosomal U2 small nuclear ribonucleoprotein (snRNP), is somatically mutated in 9.7% of affected individuals. Further analysis in 279 individuals with CLL showed that SF3B1 mutations were associated with faster disease progression and poor overall survival. This work provides the first comprehensive catalog of somatic mutations in CLL with relevant clinical correlates and defines a large set of new genes that may drive the development of this common form of leukemia. The results reinforce the idea that targeting several well-known genetic pathways, including mRNA splicing, could be useful in the treatment of CLL and other malignancies. 相似文献
97.
This paper discusses how to specify an observable high‐frequency model for a vector of time series sampled at high and low frequencies. To this end we first study how aggregation over time affects both the dynamic components of a time series and their observability, in a multivariate linear framework. We find that the basic dynamic components remain unchanged but some of them, mainly those related to the seasonal structure, become unobservable. Building on these results, we propose a structured specification method built on the idea that the models relating the variables in high and low sampling frequencies should be mutually consistent. After specifying a consistent and observable high‐frequency model, standard state‐space techniques provide an adequate framework for estimation, diagnostic checking, data interpolation and forecasting. An example using national accounting data illustrates the practical application of this method. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
98.
Rioux JD Xavier RJ Taylor KD Silverberg MS Goyette P Huett A Green T Kuballa P Barmada MM Datta LW Shugart YY Griffiths AM Targan SR Ippoliti AF Bernard EJ Mei L Nicolae DL Regueiro M Schumm LP Steinhart AH Rotter JI Duerr RH Cho JH Daly MJ Brant SR 《Nature genetics》2007,39(5):596-604
We present a genome-wide association study of ileal Crohn disease and two independent replication studies that identify several new regions of association to Crohn disease. Specifically, in addition to the previously established CARD15 and IL23R associations, we identified strong and significantly replicated associations (combined P < 10(-10)) with an intergenic region on 10q21.1 and a coding variant in ATG16L1, the latter of which was also recently reported by another group. We also report strong associations with independent replication to variation in the genomic regions encoding PHOX2B, NCF4 and a predicted gene on 16q24.1 (FAM92B). Finally, we demonstrate that ATG16L1 is expressed in intestinal epithelial cell lines and that functional knockdown of this gene abrogates autophagy of Salmonella typhimurium. Together, these findings suggest that autophagy and host cell responses to intracellular microbes are involved in the pathogenesis of Crohn disease. 相似文献
99.
A gene in the multidrug and toxic compound extrusion (MATE) family confers aluminum tolerance in sorghum 总被引:19,自引:0,他引:19
Magalhaes JV Liu J Guimarães CT Lana UG Alves VM Wang YH Schaffert RE Hoekenga OA Piñeros MA Shaff JE Klein PE Carneiro NP Coelho CM Trick HN Kochian LV 《Nature genetics》2007,39(9):1156-1161
Crop yields are significantly reduced by aluminum toxicity on highly acidic soils, which comprise up to 50% of the world's arable land. Candidate aluminum tolerance proteins include organic acid efflux transporters, with the organic acids forming non-toxic complexes with rhizosphere aluminum. In this study, we used positional cloning to identify the gene encoding a member of the multidrug and toxic compound extrusion (MATE) family, an aluminum-activated citrate transporter, as responsible for the major sorghum (Sorghum bicolor) aluminum tolerance locus, Alt(SB). Polymorphisms in regulatory regions of Alt(SB) are likely to contribute to large allelic effects, acting to increase Alt(SB) expression in the root apex of tolerant genotypes. Furthermore, aluminum-inducible Alt(SB) expression is associated with induction of aluminum tolerance via enhanced root citrate exudation. These findings will allow us to identify superior Alt(SB) haplotypes that can be incorporated via molecular breeding and biotechnology into acid soil breeding programs, thus helping to increase crop yields in developing countries where acidic soils predominate. 相似文献
100.