Search results for "Molecular"
showing 10 items of 32340 documents
Cross-Talk between ROS and Calcium in Regulation of Nuclear Activities
2010
International audience; Calcium and Reactive Oxygen Species (ROS) are acknowledged as crucial second messengers involved in the response to various biotic and abiotic stresses. However, it is still not clear how these two compounds can play a role in different signaling pathways leading the plant to a variety of processes such as root development or defense against pathogens. Recently, it has been shown that the concept of calcium and ROS signatures, initially discovered in the cytoplasm, can also be extended to the nucleus of plant cells. In addition, it has been clearly proved that both ROS and calcium signals are intimately interconnected. How this cross-talk can finally modulate the tra…
Use of chlorophyll fluorescence induction kinetics to study translocation and detoxication of DCMU-type herbicides in plant leaves
1984
Transient levels of the fluorescence induction rise were used to quantify partial photosynthesis inhibition by DCMU -type herbicides in whole leaves. Assays in different crop or weed species showed a good accuracy in measurements (generally, variation was lower than 5%). This technique was applied to the problem of varietal selectivity of wheat towards chlortoluron.
Experimental Introgression To Evaluate the Impact of Sex Specific Traits on Drosophila melanogaster Incipient Speciation
2019
AbstractSex specific traits are involved in speciation but it is difficult to determine whether their variation initiates or reinforces sexual isolation. In some insects, speciation depends of the rapid change of expression in desaturase genes coding for sex pheromones. Two closely related desaturase genes are involved in Drosophila melanogaster pheromonal communication: desat1 affects both the production and the reception of sex pheromones while desat2 is involved in their production in flies of Zimbabwe populations. There is a strong asymmetric sexual isolation between Zimbabwe populations and all other “Cosmopolitan” populations: Zimbabwe females rarely copulate with Cosmopolitan males w…
Reviewing research priorities in weed ecology, evolution and management: a horizon scan.
2018
Weedy plants pose a major threat to food security, biodiversity, ecosystem services and consequently to human health and wellbeing. However, many currently used weed management approaches are increasingly unsustainable. To address this knowledge and practice gap, in June 2014, 35 weed and invasion ecologists, weed scientists, evolutionary biologists and social scientists convened a workshop to explore current and future perspectives and approaches in weed ecology and management. A horizon scanning exercise ranked a list of 124 pre-submitted questions to identify a priority list of 30 questions. These questions are discussed under seven themed headings that represent areas for renewed and em…
Volatile components of ripe fruits of Morinda citrifolia and their effects on Drosophila
1996
Abstract The only larval resource of the specialist species, Drosophila sechellia , is ripe fruits of Morinda citrifolia . The chemical composition of this fruit, which is very toxic to most Drosophila species, was investigated and 51 compounds were abundant enough to be identified by GC-MS. The ripe fruit is characterized by a large amount of carboxylic acids, especially octanoic and hexanoic acids. The biological effects of the ripe fruit and its main acids were investigated with behavioural studies. Octanoic acid is responsible for the general toxicity of the fruit to most Drosophila species; D. sechellia is the only species which is resistant to this acid. Hexanoic acid has a unique eff…
Evolutionary Changes after Translational Challenges Imposed by Horizontal Gene Transfer
2019
International audience; Genes acquired by horizontal gene transfer (HGT) may provide the recipient organism with potentially new functions, but proper expression level and integration of the transferred genes in the novel environment are not granted. Notably, transferred genes can differ from the receiving genome in codon usage preferences, leading to impaired translation and reduced functionality. Here, we characterize the genomic and proteomic changes undergone during experimental evolution of Escherichia coli after HGT of three synonymous versions, presenting very different codon usage preference, of an antibiotic resistance gene. The experimental evolution was conducted with and without…
Negative associations between parasite avoidance, resistance and tolerance predict host health in salmonid fish populations
2020
Genetic variation in defence against parasite infections is fundamental for host–parasite evolution. The overall level of defence of a host individual or population includes mechanisms that reduce parasite exposure (avoidance), establishment (resistance) or pathogenicity (tolerance). However, how these traits operate and evolve in concert is not well understood. Here, we investigated genetic variation in and associations between avoidance, resistance and tolerance in a natural host–parasite system. Replicated populations of Atlantic salmon ( Salmo salar ) and sea trout (an anadromous form of brown trout, Salmo trutta ) were raised under common garden conditions and infected with the eye fl…
Spontaneous hybridizations between oilseed rape and wild radish
1998
The occurence of spontaneous hybridization between Brassica napus (oilseed rape) and Raphanus raphanistrum (wild radish) was investigated under different density conditions in cages and open-field experiments. Hybrids with wild radish as the seed parent were identified by screening for herbicide resistance belonging to rape. Small seed size and intermediate morphology were used to screen for hybrids with rape as the seed parent. Leaf isozyme patterns and flow cytometry provided confirmation of hybrids. Wild radish in an oilseed rape field produced as many as three interspecific hybrids per 100 plants. This is the first report of such a spontaneous event. The frequency of hybrids is expected…
Some effects of the herbicide EL-107 on cellular growth and metabolism
1987
Summary Effects of the herbicide EL-107 (N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxy-benzamide) on the growth of dicotyledonous plants are described. The herbicide did not inhibit germination but reduced the growth of rape (Brassica napus L.) by half at 0.0057 mg l−1. The most characteristic symptom induced was a swelling of the apical regions, and histological observations of root tips of Polygonum persicaria and rape revealed a progressve disappearance of the meristematic zone, which was replaced by enlarged cells almost devoid of cytoplasm. Growth of cells of Acer pseudoplatanus L. and soybean (Glycine max L.) cultured in suspension was also inhibited by EL-107, which induc…
Conservation status of freshwater mussels in Europe: state of the art and future challenges
2016
Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life-history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is uneve…