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991.
Bi Zamble H. Zamble Serge S. Yao Akr M. Adja Mahfoud Bakli Dounin D. Zoh Franoise Mathieu-Daud Serge B. Assi Franck Remoue Lionel Almeras Anne Poinsignon 《PLoS neglected tropical diseases》2021,15(12)
BackgroundCulex mosquitoes are vectors for a variety of pathogens of public health concern. New indicators of exposure to Culex bites are needed to evaluate the risk of transmission of associated pathogens and to assess the efficacy of vector control strategies. An alternative to entomological indices is the serological measure of antibodies specific to mosquito salivary antigens. This study investigated whether the human IgG response to both the salivary gland extract and the 30 kDa salivary protein of Culex quinquefasciatus may represent a proxy of human exposure to Culex bites.Methodology/Principal findingsA multidisciplinary survey was conducted with children aged 1 to 14 years living in neighborhoods with varying exposure to Culex quinquefasciatus in the city of Bouaké, Côte d’Ivoire. Children living in sites with high exposure to Cx quinquefasciatus had a significantly higher IgG response to both salivary antigens compared with children living in the control site where only very few Culex were recorded. Moreover, children from any Culex-high exposed sites had significantly higher IgG responses only to the salivary gland extract compared with children from the control village, whereas no difference was noted in the anti-30 kDa IgG response. No significant differences were noted in the specific IgG responses between age and gender. Sites and the use of a bed net were associated with the level of IgG response to the salivary gland extract and to the 30 kDa antigen, respectively.Conclusions/SignificanceThese findings suggest that the IgG response to Culex salivary gland extracts is suitable as proxy of exposure; however, the specificity to the Culex genus needs further investigation. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other specific antibody responses might be more relevant as a biomarker of exposure. These epidemiological observations may form a starting point for additional work on developing serological biomarkers of Culex exposure. 相似文献
992.
Rabbits killing birds: modelling the hyperpredation process 总被引:7,自引:1,他引:6
Franck Courchamp‡ Michel Langlais† George Sugihara 《The Journal of animal ecology》2000,69(1):154-164
1. Introduced rabbits are known to have catastrophic effects on oceanic islands, either by direct destruction of the vegetative cover, or by the resulting disturbance of indigenous vertebrates.
2. Another dramatic effect, less well known, but potentially of major importance, is the hyperpredation process. This process, related to apparent competition, predicts that an introduced prey species, well adapted to high predation pressure, could induce the extinction of an indigenous prey, through the sudden increased population size of an introduced predator. In many island ecosystems, the simultaneous presence of introduced feral cats and rabbits is thus potentially a further threat for small vertebrates endemic of these islands.
3. Through a mathematical model, we tested this hypothesis, using a tri-trophic system comprising an indigenous prey (birds), an introduced prey (rabbits) and an introduced predator (cats), and we demonstrated the theoretical existence of the hyperpredation process.
4. In addition, the numerical analysis of the model allowed a quantification of this process. It shows that the conditions required for an indigenous species to cope with the hyperpredation process imply very high intrinsic growth rates and/or carrying capacity, as well as behavioural anti-predator response to the introduced predator. Since these conditions are unlikely to be met, this process is a further potential threat to most indigenous vertebrate prey.
5. Finally, our model shows that, although it can be induced by both types of adaptation together or alone, behavioural adaptations alone are more powerful in generating the hyperpredation process, than are life history traits adaptations. 相似文献
2. Another dramatic effect, less well known, but potentially of major importance, is the hyperpredation process. This process, related to apparent competition, predicts that an introduced prey species, well adapted to high predation pressure, could induce the extinction of an indigenous prey, through the sudden increased population size of an introduced predator. In many island ecosystems, the simultaneous presence of introduced feral cats and rabbits is thus potentially a further threat for small vertebrates endemic of these islands.
3. Through a mathematical model, we tested this hypothesis, using a tri-trophic system comprising an indigenous prey (birds), an introduced prey (rabbits) and an introduced predator (cats), and we demonstrated the theoretical existence of the hyperpredation process.
4. In addition, the numerical analysis of the model allowed a quantification of this process. It shows that the conditions required for an indigenous species to cope with the hyperpredation process imply very high intrinsic growth rates and/or carrying capacity, as well as behavioural anti-predator response to the introduced predator. Since these conditions are unlikely to be met, this process is a further potential threat to most indigenous vertebrate prey.
5. Finally, our model shows that, although it can be induced by both types of adaptation together or alone, behavioural adaptations alone are more powerful in generating the hyperpredation process, than are life history traits adaptations. 相似文献
993.
Jarrousse Anne-Sophie Gautier Karine Apcher Sébastien Badaoui Saloua Boissonnet Gérard Dadet Marie-hélène Henry Laurent Bureau Jean-Paul Schmid Hans-Peter Petit Franck 《Molecular biology reports》1999,26(1-2):113-117
The interrelationships between proteasomes and viral gene products are very complex. 20S proteasomes associate with a number of viral mRNAs which are cleaved by proteasome's associated endonuclease activity. In addition proteasome's endopeptidase activities are involved in the presentation of viral antigens. Viral proteins of different origin associate with the 20S and 26S complexes and interfere with their enzymatic activities. A major part of this review deals with the interactions between 20S proteasomes and the gene products of the human immunodeficiency virus (HIV) which has been studied in detail by our group. 相似文献
994.
Thomas Gaspar Claire Kevers Badia Bisbis Thierry Franck Michèle Crevecoeur Hubert Greppin Jacques Dommes 《In vitro cellular & developmental biology. Plant》2000,36(3):171-181
Summary The aptitude for organogenesis from normal hormone-dependent cultures very commonly decreases as the tissues are serially
subcultured. The reasons for the loss of regenerative ability may vary under different circumstances: genetic variation in
the cell population, epigenetic changes, disappearance of an organogenesis-promoting substance, etc. The same reasons may
be evoked for the progressive and eventually irreversible loss of organogenic totipotency in the course of neoplastic progressions
from hormone-independent tumors and hyperhydric teratomas to cancers. As in animal cells, plant cells at the end of a neoplastic
progression have probably undergone several independent genetic accidents with cumulative effects. They indeed are characterized
by atypical biochemical cycles from which they are apparently unable to escape. The metabolic changes are probably not the
primary defects that cause cancer, rather they may allow the cells to survive. How these changes, namely an oxidative stress,
affect organogenesis is not known. The literature focuses on somatic mutations and epigenetic changes that cause aberrant
regulation of cell cycle genes and their machinery. 相似文献
995.
Plant peptide hormones are important players that control various aspects of the lives of plants. RAPID ALKALINIZATION FACTOR (RALF) peptides have recently emerged as important players in multiple physiological processes. Numerous studies have increased our understanding of the evolutionary processes that shaped the RALF family of peptides. Nevertheless, to date, there is no comprehensive, family-wide functional study on RALF peptides. Here, we analyzed the phylogeny of the proposed multigenic RALF peptide family in the model plant Arabidopsis (Arabidopsis thaliana), ecotype Col-0, and tested a variety of physiological responses triggered by RALFs. Our phylogenetic analysis reveals that two of the previously proposed RALF peptides are not genuine RALF peptides, which leads us to propose a revision to the consensus AtRALF peptide family annotation. We show that the majority of AtRALF peptides, when applied exogenously as synthetic peptides, induce seedling or root growth inhibition and modulate reactive oxygen species (ROS) production in Arabidopsis. Moreover, our findings suggest that alkalinization and growth inhibition are, generally, coupled characteristics of RALF peptides. Additionally, we show that for the majority of the peptides, these responses are genetically dependent on FERONIA, suggesting a pivotal role for this receptor kinase in the perception of multiple RALF peptides.Synthetic RAPID ALKALINIZATION FACTOR peptides induced a variety of physiological responses, many of which depend on FERONIA, a receptor kinase with functions in development and defense 相似文献
996.
Colin Thomas Maximilien Cosme Cdric Gaucherel Franck Pommereau 《PLoS computational biology》2022,18(6)
Model-checking is a methodology developed in computer science to automatically assess the dynamics of discrete systems, by checking if a system modelled as a state-transition graph satisfies a dynamical property written as a temporal logic formula. The dynamics of ecosystems have been drawn as state-transition graphs for more than a century, ranging from state-and-transition models to assembly graphs. Model-checking can provide insights into both empirical data and theoretical models, as long as they sum up into state-transition graphs. While model-checking proved to be a valuable tool in systems biology, it remains largely underused in ecology apart from precursory applications.This article proposes to address this situation, through an inventory of existing ecological STGs and an accessible presentation of the model-checking methodology. This overview is illustrated by the application of model-checking to assess the dynamics of a vegetation pathways model. We select management scenarios by model-checking Computation Tree Logic formulas representing management goals and built from a proposed catalogue of patterns. In discussion, we sketch bridges between existing studies in ecology and available model-checking frameworks. In addition to the automated analysis of ecological state-transition graphs, we believe that defining ecological concepts with temporal logics could help clarify and compare them. 相似文献
997.
998.
Sophien Kamoun Oliver Furzer Jonathan D. G. Jones Howard S. Judelson Gul Shad Ali Ronaldo J. D. Dalio Sanjoy Guha Roy Leonardo Schena Antonios Zambounis Franck Panabières David Cahill Michelina Ruocco Andreia Figueiredo Xiao‐Ren Chen Jon Hulvey Remco Stam Kurt Lamour Mark Gijzen Brett M. Tyler Niklaus J. Grünwald M. Shahid Mukhtar Daniel F. A. Tomé Mahmut Tör Guido Van Den Ackerveken John McDowell Fouad Daayf William E. Fry Hannele Lindqvist‐Kreuze Harold J. G. Meijer Benjamin Petre Jean Ristaino Kentaro Yoshida Paul R. J. Birch Francine Govers 《Molecular Plant Pathology》2015,16(4):413-434
Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens which threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant‐pathogenic oomycete species based on scientific and economic importance. In total, we received 263 votes from 62 scientists in 15 countries for a total of 33 species. The Top 10 species and their ranking are: (1) Phytophthora infestans; (2, tied) Hyaloperonospora arabidopsidis; (2, tied) Phytophthora ramorum; (4) Phytophthora sojae; (5) Phytophthora capsici; (6) Plasmopara viticola; (7) Phytophthora cinnamomi; (8, tied) Phytophthora parasitica; (8, tied) Pythium ultimum; and (10) Albugo candida. This article provides an introduction to these 10 taxa and a snapshot of current research. We hope that the list will serve as a benchmark for future trends in oomycete research. 相似文献
999.
Sonthi M Cantet F Toubiana M Trapani MR Parisi MG Cammarata M Roch P 《Fish & shellfish immunology》2012,32(1):45-50
We previously reported the nucleotide sequences and diversity of mytimycin (MytM) from the Mediterranean mussel, Mytilus galloprovincialis. Using real-time PCR (q-PCR), we observed that the MytM gene was mainly expressed in circulating hemocytes and to a less extent in the mantle. In vivo challenge with bacteria or with the yeast, Candida albicans, did not increase the expression as measured by q-PCR in hemocytes. By contrast, injection of the filamentous fungus, Fusarium oxysporum, induced a sudden and strong increase of expression at 9h p.i. (stimulation index of 25.7 ± 2.1). Optimum stimulating dose was 104 spores of F. oxysporum per mussel. In the same samples, AMP mytilin and myticin showed no stimulation. Consequently, we hypothesized the existence of 2 different signal transduction pathways, one activated by bacteria and yeast, the other triggered by filamentous fungi. A second challenge performed with F. oxysporum 24 h after the first challenge induced an increase of MytM gene expression (stimulation index of 3.5 ± 1.7). However, this second increase was significantly lower than the first, suggesting less efficient response rather than significant protection. 相似文献
1000.
Georges Pignde Hui-Jie Wang Franck Fudalej Michel Seman Claude Gaillardin Jean-Marc Nicaud 《Applied microbiology》2000,66(8):3283-3289
We synthesized a Yarrowia lipolytica strain overproducing lipase for industrial applications by using long terminal repeat (ζ) of the Y. lipolytica retrotransposon Ylt1 and an allele of URA3 with a promoter deletion to construct JMP3. JMP3 is a derivative of plasmid pHSS6 carrying a NotI-NotI cassette which contains a defective URA3 allele, a polylinker sequence, and the ζ region for targeting to multiple sites in the genome of the recipient. We inserted the LIP2 gene (encoding extracellular lipase) under the control of the strong POX2 promoter into JMP3 to generate JMP6. The pHSS6 region was removed by NotI digestion prior to transformation. Two Y. lipolytica strains transformed with the JMP6 LIP2 cassette had a mean of 10 integrated copies devoid of the Escherichia coli region, corresponding to an autocloning event. The copy number in the transformants was stable even after 120 generations in nonselective and lipase-inducing conditions. The resulting strains could produce 0.5 g of active lipase per liter in the supernatant, 40 times more than the single-copy strain with the LIP2 promoter. This work provides a new expression system in Y. lipolytica that results in strains devoid of bacterial DNA and in strains producing a high level of lipase for industrial uses, waste treatment, and pancreatic insufficiency therapy. 相似文献