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161.
162.
Clivot Hugues Petitjean Caroline Marron Nicolas Dallé Erwin Genestier Julie Blaszczyk Nicolas Santenoise Philippe Laflotte Alexandre Piutti Séverine 《Plant and Soil》2020,453(1-2):189-207
Plant and Soil - A field experiment was conducted to evaluate the effects of alley cropping systems on microbial activity and soil organic matter (SOM) pools. We hypothesized that enzyme activity... 相似文献
163.
Potential for Virus Endogenization in Humans through Testicular Germ Cell Infection: the Case of HIV
164.
Demenois Julien Merino-Martín Luis Fernandez Nuñez Nicolas Stokes Alexia Carriconde Fabian 《Plant and Soil》2020,448(1-2):213-229
Plant and Soil - Understanding how soil aggregate stability (MWD) is influenced by microbial diversity and abundance can be crucial for ecological restoration in severely disturbed areas. We... 相似文献
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Rosie Drinkwater Joseph Williamson Tom Swinfield Nicolas J. Deere Matthew J. Struebig Elizabeth L. Clare David Coomes Stephen J. Rossiter 《Biotropica》2020,52(2):302-312
Blood-feeding invertebrates are emerging model taxa in biodiversity assessments, both as indicators of mammal abundance and also as sources of mammal DNA for identification. Among these, terrestrial leeches arguably offer the greatest promise; they are abundant and widespread in the humid tropics, and their blood meals can be easily assayed to establish diet. Unfortunately, terrestrial leeches are understudied, with little known about their ecology and behavior. Such information is needed to evaluate their utility as ecological indicators and to account for potential sampling biases that might arise from habitat preferences. By combining occupancy modeling and thermal tolerance assays, we determined the factors affecting species occurrence in the related terrestrial brown (Haemadipsa sumatrana) and tiger leech (Haemadipsa picta), both of which are widespread in tropical forests in Southeast Asia. We sampled both species across a degraded forest landscape in Sabah, Borneo, in wet and dry seasons, associating occurrence with habitat-level metrics. We found that, for both species, detection probability increased with canopy height regardless of season. Additionally, increased vegetation heterogeneity had a strong negative influence on brown leech occurrence in the dry season, implying an interaction between vegetation structure and climate. However, we found no difference in physiological thermal tolerance (CTMAX) between the two species. Finally, using a reduced dataset, we found a small improvement in brown leech model fit when including mammal abundance. Our results suggest that the presence of terrestrial leeches may act as useful ecological indicators of habitat quality and potentially mammalian abundance. Abstract in Indonesia is available with online material. 相似文献
168.
Marcus Weinguny Peter Eisenhut Gerald Klanert Nikolaus Virgolini Nicolas Marx Andreas Jonsson Daniel Ivansson Ann Lövgren Nicole Borth 《Biotechnology and bioengineering》2020,117(11):3435-3447
Chinese hamster ovary (CHO) cells produce a large share of today's biopharmaceuticals. Still, the generation of satisfactory producer cell lines is a tedious undertaking. Recently, it was found that CHO cells, when exposed to new environmental conditions, modify their epigenome, suggesting that cells adapt their gene expression pattern to handle new challenges. The major aim of the present study was to employ artificially induced, random changes in the DNA-methylation pattern of CHO cells to diversify cell populations and consequently increase the finding of cell lines with improved cellular characteristics. To achieve this, DNA methyltransferases and/or the ten-eleven translocation enzymes were downregulated by RNA interference over a time span of ∼16 days. Methylation analysis of the resulting cell pools revealed that the knockdown of DNA methyltransferases was highly effective in randomly demethylating the genome. The same approach, when applied to stable CHO producer cells resulted in (a) an increased productivity diversity in the cell population, and (b) a higher number of outliers within the population, which resulted in higher specific productivity and titer in the sorted cells. These findings suggest that epigenetics play a previously underestimated, but actually important role in defining the overall cellular behavior of production clones. 相似文献
169.
Hilde Schneemann Bianca De Sanctis Denis Roze Nicolas Bierne John J. Welch 《Evolution; international journal of organic evolution》2020,74(12):2575-2590
When divergent populations form hybrids, hybrid fitness can vary with genome composition, current environmental conditions, and the divergence history of the populations. We develop analytical predictions for hybrid fitness, which incorporate all three factors. The predictions are based on Fisher's geometric model, and apply to a wide range of population genetic parameter regimes and divergence conditions, including allopatry and parapatry, local adaptation, and drift. Results show that hybrid fitness can be decomposed into intrinsic effects of admixture and heterozygosity, and extrinsic effects of the (local) adaptedness of the parental lines. Effect sizes are determined by a handful of geometric distances, which have a simple biological interpretation. These distances also reflect the mode and amount of divergence, such that there is convergence toward a characteristic pattern of intrinsic isolation. We next connect our results to the quantitative genetics of line crosses in variable or patchy environments. This means that the geometrical distances can be estimated from cross data, and provides a simple interpretation of the “composite effects.” Finally, we develop extensions to the model, involving selectively induced disequilibria, and variable phenotypic dominance. The geometry of fitness landscapes provides a unifying framework for understanding speciation, and wider patterns of hybrid fitness. 相似文献
170.
Anne Gibaud Nicolas Vogt Olivier Brison Michelle Debatisse Bernard Malfoy 《Nucleic acids research》2013,41(17):8210-8219
The mechanisms of formation of intrachromosomal amplifications in tumours are still poorly understood. By using quantitative polymerase chain reaction, DNA sequencing, chromosome walking, in situ hybridization on metaphase chromosomes and whole-genome analysis, we studied two cancer cell lines containing an MYC oncogene amplification with acquired copies ectopically inserted in rearranged chromosomes 17. These intrachromosomal amplifications result from the integration of extrachromosomal DNA molecules. Replication stress could explain the formation of the double-strand breaks involved in their insertion and in the rearrangements of the targeted chromosomes. The sequences of the junctions indicate that homologous recombination was not involved in their formation and support a non-homologous end-joining process. The replication stress-inducible common fragile sites present in the amplicons may have driven the intrachromosomal amplifications. Mechanisms associating break-fusion-bridge cycles and/or chromosome fragmentation may have led to the formation of the uncovered complex structures. To our knowledge, this is the first characterization of an intrachromosomal amplification site at nucleotide resolution. 相似文献