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141.
Saintenac C Faure S Remay A Choulet F Ravel C Paux E Balfourier F Feuillet C Sourdille P 《Chromosoma》2011,120(2):185-198
In bread wheat (Triticum aestivum L.), initial studies using deletion lines indicated that crossover (CO) events occur mainly in the telomeric regions of the
chromosomes with a possible correlation with the presence of genes. However, little is known about the distribution of COs
at the sequence level. To investigate this, we studied in detail the pattern of COs along a contig of 3.110 Mb using two F2
segregating populations (Chinese Spring × Renan (F2-CsRe) and Chinese Spring × Courtot (F2-CsCt)) each containing ~2,000 individuals.
The availability of the sequence of the contig from Cs enabled the development of 318 markers among which 23 co-dominant polymorphic
markers (11 SSRs and 12 SNPs) were selected for CO distribution analyses. The distribution of CO events was not homogeneous
throughout the contig, ranging from 0.05 to 2.77 cM/Mb, but was conserved between the two populations despite very different
contig recombination rate averages (0.82 cM/Mb in F2-CsRe vs 0.35 cM/Mb in F2-CsCt). The CO frequency was correlated with
the percentage of coding sequence in Cs and with the polymorphism rate between Cs and Re or Ct in both populations, indicating
an impact of these two factors on CO distribution. At a finer scale, COs were found in a region covering 2.38 kb, spanning
a gene coding for a glycosyl transferase (Hga3), suggesting the presence of a CO hotspot. A non-crossover event covering at least 453 bp was also identified in the same
interval. From these results, we can conclude that gene content could be one of the factors driving recombination in bread
wheat. 相似文献
142.
Masha T. van der Sande Helge Bruelheide Wayne Dawson Jürgen Dengler Franz Essl Richard Field Sylvia Haider Mark van Kleunen Holger Kreft Joern Pagel Jan Pergl Oliver Purschke Petr Pyek Patrick Weigelt Marten Winter Fabio Attorre Isabelle Aubin Erwin Bergmeier Milan Chytrý Matteo Dainese Michele De Sanctis Jaime Fagundez Valentin Golub Greg R. Guerin Alvaro G. Gutirrez Ute Jandt Florian Jansen Borja Jimnez‐Alfaro Jens Kattge Elizabeth Kearsley Stefan Klotz Koen Kramer Marco Moretti Ülo Niinemets Robert K. Peet Josep Penuelas Petr Petík Peter B. Reich Brody Sandel Marco Schmidt Maria Sibikova Cyrille Violle Timothy J. S. Whitfeld Thomas Wohlgemuth Tiffany M. Knight 《Global Ecology and Biogeography》2020,29(2):281-294
143.
Cyrille Ndo Frédéric Simard Pierre Kengne Parfait Awono-Ambene Isabelle Morlais Igor Sharakhov Didier Fontenille Christophe Antonio-Nkondjio 《PloS one》2013,8(3)
Background
The Anopheles nili group of mosquitoes includes important vectors of human malaria in equatorial forest and humid savannah regions of sub-Saharan Africa. However, it remains largely understudied, and data on its populations’ bionomics and genetic structure are crucially lacking. Here, we used a combination of nuclear (i.e. microsatellite and ribosomal DNA) and mitochondrial DNA markers to explore and compare the level of genetic polymorphism and divergence among populations and species of the group in the savannah and forested areas of Cameroon, Central Africa.Principal Findings
All the markers provided support for the current classification within the An. nili group. However, they revealed high genetic heterogeneity within An. nili s.s. in deep equatorial forest environment. Nuclear markers showed the species to be composed of five highly divergent genetic lineages that differed by 1.8 to 12.9% of their Internal Transcribed Spacer 2 (ITS2) sequences, implying approximate divergence time of 0.82 to 5.86 million years. However, mitochondrial data only detected three major subdivisions, suggesting different evolutionary histories of the markers.Conclusions/Significance
This study enlightened additional cryptic genetic diversity within An. nili s.s. in the deep equatorial forest environment of South Cameroon, reflecting a complex demographic history for this major vector of malaria in this environment. These preliminary results should be complemented by further studies which will shed light on the distribution, epidemiological importance and evolutionary history of this species group in the African rainforest, providing opportunities for in-depth comparative studies of local adaptation and speciation in major African malaria vectors. 相似文献144.
Martin de Luis Katarina ?ufar Alfredo Di Filippo Klemen Novak Andreas Papadopoulos Gianluca Piovesan Cyrille B. K. Rathgeber José Raventós Miguel Angel Saz Kevin T. Smith 《PloS one》2013,8(12)
We investigated the variability of the climate-growth relationship of Aleppo pine across its distribution range in the Mediterranean Basin. We constructed a network of tree-ring index chronologies from 63 sites across the region. Correlation function analysis identified the relationships of tree-ring index to climate factors for each site. We also estimated the dominant climatic gradients of the region using principal component analysis of monthly, seasonal, and annual mean temperature and total precipitation from 1,068 climatic gridpoints. Variation in ring width index was primarily related to precipitation and secondarily to temperature. However, we found that the dendroclimatic relationship depended on the position of the site along the climatic gradient. In the southern part of the distribution range, where temperature was generally higher and precipitation lower than the regional average, reduced growth was also associated with warm and dry conditions. In the northern part, where the average temperature was lower and the precipitation more abundant than the regional average, reduced growth was associated with cool conditions. Thus, our study highlights the substantial plasticity of Aleppo pine in response to different climatic conditions. These results do not resolve the source of response variability as being due to either genetic variation in provenance, to phenotypic plasticity, or a combination of factors. However, as current growth responses to inter-annual climate variability vary spatially across existing climate gradients, future climate-growth relationships will also likely be determined by differential adaptation and/or acclimation responses to spatial climatic variation. The contribution of local adaptation and/or phenotypic plasticity across populations to the persistence of species under global warming could be decisive for prediction of climate change impacts across populations. In this sense, a more complex forest dynamics modeling approach that includes the contribution of genetic variation and phenotypic plasticity can improve the reliability of the ecological inferences derived from the climate-growth relationships. 相似文献
145.
Davita Pillay Julien Izotte Regassa Fikru Philipe Büscher Hermogenes Mucache Luis Neves Alain Boulangé Momar Talla Seck Jérémy Bouyer Grant B. Napier Cyrille Chevtzoff Virginie Coustou Théo Baltz 《PloS one》2013,8(10)
Background
Diagnosis of African animal trypanosomosis is vital to controlling this severe disease which hampers development across 10 million km2 of Africa endemic to tsetse flies. Diagnosis at the point of treatment is currently dependent on parasite detection which is unreliable, and on clinical signs, which are common to several other prevalent bovine diseases.Methodology/Principle Findings
the repeat sequence of the GM6 antigen of Trypanosoma vivax (TvGM6), a flagellar-associated protein, was analysed from several isolates of T. vivax and found to be almost identical despite the fact that T. vivax is known to have high genetic variation. The TvGM6 repeat was recombinantly expressed in E. coli and purified. An indirect ELISA for bovine sera based on this antigen was developed. The TvGM6 indirect ELISA had a sensitivity of 91.4% (95% CI: 91.3 to 91.6) in the period following 10 days post experimental infection with T. vivax, which decreased ten-fold to 9.1% (95% CI: 7.3 to 10.9) one month post treatment. With field sera from cattle infected with T. vivax from two locations in East and West Africa, 91.5% (95% CI: 83.2 to 99.5) sensitivity and 91.3% (95% CI: 78.9 to 93.1) specificity was obtained for the TvGM6 ELISA using the whole trypanosome lysate ELISA as a reference. For heterologous T. congolense field infections, the TvGM6 ELISA had a sensitivity of 85.1% (95% CI: 76.8 to 94.4).Conclusion/Significance
this study is the first to analyse the GM6 antigen of T. vivax and the first to test the GM6 antigen on a large collection of sera from experimentally and naturally infected cattle. This study demonstrates that the TvGM6 is an excellent candidate antigen for the development of a point-of-treatment test for diagnosis of T. vivax, and to a lesser extent T. congolense, African animal trypanosomosis in cattle. 相似文献146.
Jean-Fran?ois Humbert Valérie Barbe Amel Latifi Muriel Gugger Alexandra Calteau Therese Coursin Aurélie Lajus Vanina Castelli Sophie Oztas Ga?lle Samson Cyrille Longin Claudine Medigue Nicole Tandeau de Marsac 《PloS one》2013,8(8)
Microcystis aeruginosa is one of the most common bloom-forming cyanobacteria in freshwater ecosystems worldwide. This species produces numerous secondary metabolites, including microcystins, which are harmful to human health. We sequenced the genomes of ten strains of M. aeruginosa in order to explore the genomic basis of their ability to occupy varied environments and proliferate. Our findings show that M. aeruginosa genomes are characterized by having a large open pangenome, and that each genome contains similar proportions of core and flexible genes. By comparing the GC content of each gene to the mean value of the whole genome, we estimated that in each genome, around 11% of the genes seem to result from recent horizontal gene transfer events. Moreover, several large gene clusters resulting from HGT (up to 19 kb) have been found, illustrating the ability of this species to integrate such large DNA molecules. It appeared also that all M. aeruginosa displays a large genomic plasticity, which is characterized by a high proportion of repeat sequences and by low synteny values between the strains. Finally, we identified 13 secondary metabolite gene clusters, including three new putative clusters. When comparing the genomes of Microcystis and Prochlorococcus, one of the dominant picocyanobacteria living in marine ecosystems, our findings show that they are characterized by having almost opposite evolutionary strategies, both of which have led to ecological success in their respective environments. 相似文献
147.
Martin Tremblay Richard C. Bethell Michael G. Cordingley Patrick DeRoy Jianmin Duan Martin Duplessis Paul J. Edwards Anne-Marie Faucher Ted Halmos Clint A. James Cyrille Kuhn Jean-Éric Lacoste Louie Lamorte Steven R. LaPlante Éric Malenfant Joannie Minville Louis Morency Sébastien Morin Claudio F. Sturino 《Bioorganic & medicinal chemistry letters》2013,23(9):2775-2780
148.
Zbinden C 《Journal of computational neuroscience》2011,31(2):285-304
In this paper, we highlight the topological properties of leader neurons whose existence is an experimental fact. Several
experimental studies show the existence of leader neurons in population bursts of activity in 2D living neural networks (Eytan
and Marom, J Neurosci 26(33):8465–8476, 2006; Eckmann et al., New J Phys 10(015011), 2008). A leader neuron is defined as a neuron which fires at the beginning of a burst (respectively network spike) more often
than we expect by chance considering its mean firing rate. This means that leader neurons have some burst triggering power
beyond a chance-level statistical effect. In this study, we characterize these leader neuron properties. This naturally leads
us to simulate neural 2D networks. To build our simulations, we choose the leaky integrate and fire (lIF) neuron model (Gerstner
and Kistler 2002; Cessac, J Math Biol 56(3):311–345, 2008), which allows fast simulations (Izhikevich, IEEE Trans Neural Netw 15(5):1063–1070, 2004; Gerstner and Naud, Science 326:379–380, 2009). The dynamics of our lIF model has got stable leader neurons in the burst population that we simulate. These leader neurons
are excitatory neurons and have a low membrane potential firing threshold. Except for these two first properties, the conditions
required for a neuron to be a leader neuron are difficult to identify and seem to depend on several parameters involved in
the simulations themselves. However, a detailed linear analysis shows a trend of the properties required for a neuron to be
a leader neuron. Our main finding is: A leader neuron sends signals to many excitatory neurons as well as to few inhibitory
neurons and a leader neuron receives only signals from few other excitatory neurons. Our linear analysis exhibits five essential
properties of leader neurons each with different relative importance. This means that considering a given neural network with
a fixed mean number of connections per neuron, our analysis gives us a way of predicting which neuron is a good leader neuron
and which is not. Our prediction formula correctly assesses leadership for at least ninety percent of neurons. 相似文献
149.
Over the past 20 years, the field of foldamers has rapidly increased. Many β-peptides have already been described and shown
interesting properties. γ-Peptides have more recently emerged but seem to be very interesting as well. In this review, we
will cover every peptidomimetic oligomer that contains a γ-amino acid or an analogue and presents a structural feature. It
includes γ-peptides but also hybrid α–γ peptides, β–γ peptides and analogues such as oligoureas or aminoxy acids. We will
present the biological properties of these oligomers. 相似文献
150.