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Rosario Gil Eugeni Belda María J Gosalbes Luis Delaye Agnès Vallier Carole Vincent-Monégat Abdelaziz Heddi Francisco J Silva Andrés Moya Amparo Latorre 《International microbiology》2008,11(1):41-48
Bacteria that establish an obligate intracellular relationship with eukaryotic hosts undergo an evolutionary genomic reductive process. Recent studies have shown an increase in the number of mobile elements in the first stage of the adaptive process towards intracellular life, although these elements are absent in ancient endosymbionts. Here, the genome of SOPE, the obligate mutualistic endosymbiont of rice weevils, was used as a model to analyze the initial events that occur after symbiotic integration. During the first phases of the SOPE genome project, four different types of insertion sequence (IS) elements, belonging to well-characterized IS families from gamma-proteobacteria, were identified. In the present study, these elements, which may represent more than 20% of the complete genome, were completely characterized; their relevance as a source of gene inactivation, chromosomal rearrangements, and as participants in the genome reductive process are discussed herein. 相似文献
114.
Our understanding of prokaryote-eukaryote symbioses as a source of evolutionary innovation has been rapidly increased by the advent of genomics, which has made possible the biological study of uncultivable endosymbionts. Genomics is allowing the dissection of the evolutionary process that starts with host invasion then progresses from facultative to obligate symbiosis and ends with replacement by, or coexistence with, new symbionts. Moreover, genomics has provided important clues on the mechanisms driving the genome-reduction process, the functions that are retained by the endosymbionts, the role of the host, and the factors that might determine whether the association will become parasitic or mutualistic. 相似文献
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Christophe Kunz Frauke Focke Yusuke Saito David Schuermann Teresa Lettieri Jim Selfridge Primo Schr 《PLoS biology》2009,7(4)
5-Fluorouracil (5-FU), a chemotherapeutic drug commonly used in cancer treatment, imbalances nucleotide pools, thereby favoring misincorporation of uracil and 5-FU into genomic DNA. The processing of these bases by DNA repair activities was proposed to cause DNA-directed cytotoxicity, but the underlying mechanisms have not been resolved. In this study, we investigated a possible role of thymine DNA glycosylase (TDG), one of four mammalian uracil DNA glycosylases (UDGs), in the cellular response to 5-FU. Using genetic and biochemical tools, we found that inactivation of TDG significantly increases resistance of both mouse and human cancer cells towards 5-FU. We show that excision of DNA-incorporated 5-FU by TDG generates persistent DNA strand breaks, delays S-phase progression, and activates DNA damage signaling, and that the repair of 5-FU–induced DNA strand breaks is more efficient in the absence of TDG. Hence, excision of 5-FU by TDG, but not by other UDGs (UNG2 and SMUG1), prevents efficient downstream processing of the repair intermediate, thereby mediating DNA-directed cytotoxicity. The status of TDG expression in a cancer is therefore likely to determine its response to 5-FU–based chemotherapy. 相似文献
117.
Guidugli MC Accoroni KA Mestriner MA Contel EP Martinez CA Alzate-Marin AL 《Genetics and molecular biology》2010,33(1):131-134
Twelve microsatellite loci previously developed in the tropical tree Cariniana estrellensis were genetically characterized in Cariniana legalis. Polymorphisms were assessed in 28 C. legalis individuals found between the Pardo and Mogi-Guaçu River basins in the state of São Paulo, Brazil. Of the 12 loci, 10 were polymorphic and exhibited Mendelian inheritance. The allelic richness at each locus ranged from 2-11, with an average of 7 alleles per locus, and the expected heterozygosity ranged from 0.07-0.88. These loci showed a high probability of paternity exclusion. The characteristics of these heterologous microsatellite markers indicate that they are suitable tools for investigating questions concerning population genetics in C. legalis. 相似文献
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Nicole M Gerardo Boran Altincicek Caroline Anselme Hagop Atamian Seth M Barribeau de Martin Vos Elizabeth J Duncan Jay D Evans Toni Gabaldón Murad Ghanim Adelaziz Heddi Isgouhi Kaloshian Amparo Latorre Andres Moya Atsushi Nakabachi Benjamin J Parker Vincente Pérez-Brocal Miguel Pignatelli Yvan Rahbé John S Ramsey Chelsea J Spragg Javier Tamames Daniel Tamarit Cecilia Tamborindeguy Caroline Vincent-Monegat Andreas Vilcinskas 《Genome biology》2010,11(2):1-17
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Gloria Cosoli Lorenzo Scalise Graziano Cerri Paola Russo Gerardo Tricarico Enrico Primo Tomasini 《Computer methods in biomechanics and biomedical engineering》2017,20(6):682-690
In dentistry possible inflammatory episodes of oral cavity can be very frequent (periodontitis, mucositis, peri-implantitis) and they can have serious consequences. Indeed, peri-implantitis is still the principal cause of implant failure. Impedance values of biological tissues are related to the physiological/pathological state of the tissue itself. In fact, an inflamed site exhibits an impedance value lower than that of the corresponding healthy tissue. Based on these observations, the aim of this work is to determine if impedancemetric measurements are able to provide information about the inflammatory state of tissues. A numerical 3D model has been realized to simulate the measurement conditions present in the event of inflammation around a dental implant. The aim is to understand if it is possible to determine the presence of an inflamed tissue and to locate its site, so that the treatment could be specifically focused in that specific area. A simplified geometry reproducing the implant has been realized in order to validate the numerical model by means of experimental measurements. The obtained results are satisfactorily accurate, so the model can be considered reliable. Therefore, multiple simulations have been run on the original model to carry out a parametric study in terms of different conductivity values, different volumes of inflamed tissues and different measurement frequencies. The advantages and limits of such a method have been shown to properly define the main constraints for the system design. 相似文献