Littérature scientifique sur le sujet « Parental origin effects »
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Articles de revues sur le sujet "Parental origin effects"
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Cattanach, B. M. « Parental origin effects in mice ». Development 97, Supplement (1 octobre 1986) : 137–50. http://dx.doi.org/10.1242/dev.97.supplement.137.
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Nuclear transplantation experiments in mice, reviewed elsewhere in this Symposium, have clearly demonstrated that the maternal and paternal genomes from which the embryo is formed are not functionally equivalent. The paternal genome appears to be essential for the normal development of extraembryonic tissues and the maternal genome for some stage of embryonic development. These findings provide some explanation for the observations that in mammals diploid parthenotes possessing two maternal genomes fail to survive (Markert, 1982) and that, in man, embryos with two paternal chromosome sets are inviable, forming hydatidiform moles (Kajii & Ohama, 1977). It has been proposed that a specific ‘imprinting’ of the paternal genomes occurs during gametogenesis so that the presence of both a female and male pronculeus is essential in an egg for full-term development (Barton, Surani & Norris, 1984; McGrath & Solter, 1984a; Surani, Barton & Norris, 1984).
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Paterson, A. D. « Analysis of parental-origin effects in linkage data ». Molecular Psychiatry 5, no 2 (mars 2000) : 125–26. http://dx.doi.org/10.1038/sj.mp.4000667.
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Adams, S., R. Vinkenoog, M. Spielman, H. G. Dickinson et R. J. Scott. « Parent-of-origin effects on seed development in Arabidopsis thaliana require DNA methylation ». Development 127, no 11 (1 juin 2000) : 2493–502. http://dx.doi.org/10.1242/dev.127.11.2493.
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Some genes in mammals and flowering plants are subject to parental imprinting, a process by which differential epigenetic marks are imposed on male and female gametes so that one set of alleles is silenced on chromosomes contributed by the mother while another is silenced on paternal chromosomes. Therefore, each genome contributes a different set of active alleles to the offspring, which develop abnormally if the parental genome balance is disturbed. In Arabidopsis, seeds inheriting extra maternal genomes show distinctive phenotypes such as low weight and inhibition of mitosis in the endosperm, while extra paternal genomes result in reciprocal phenotypes such as high weight and endosperm overproliferation. DNA methylation is known to be an essential component of the parental imprinting mechanism in mammals, but there is less evidence for this in plants. For the present study, seed development was examined in crosses using a transgenic Arabidopsis line with reduced DNA methylation. Crosses between hypomethylated and wild-type diploid plants produced similar seed phenotypes to crosses between plants with normal methylation but different ploidies. This is consistent with a model in which hypomethylation of one parental genome prevents silencing of alleles that would normally be active only when inherited from the other parent - thus phenocopying the effects of extra genomes. These results suggest an important role for methylation in parent-of-origin effects, and by inference parental imprinting, in plants. The phenotype of biparentally hypomethylated seeds is less extreme than the reciprocal phenotypes of uniparentally hypomethylated seeds. The observation that development is less severely affected if gametes of both sexes (rather than just one) are ‘neutralized’ with respect to parent-of-origin effects supports the hypothesis that parental imprinting is not necessary to regulate development.
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Lefort-Buson, M., B. Guillot-Lemoine et Y. Dattee. « Heterosis and genetic distance in rapeseed (Brassica napus L.) : crosses between European and Asiatic selfed lines ». Genome 29, no 3 (1 juin 1987) : 413–18. http://dx.doi.org/10.1139/g87-072.
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Different types of F1 hybrids from the same and different geographic origins were studied. European and Asiatic inbred lines were hand crossed in three ways: a diallel design among European lines (European group), a diallel design among Asiatic lines (Asiatic group), and a factorial design between European and Asiatic lines (mixed group). Selfed lines and F1 hybrids of each group have been tested in the field at a normal seeding rate (4 kg/ha) in replicated trials. The experiment has been conducted over 2 years in two localities. Mixed group F1 hybrids were taller and more productive in seed yield than both European and Asiatic ones. For flowering, they were intermediate between both parents and close to the check Bienvenu. Variability was not organized the same way among the three groups. It was mainly additive for hybrids from lines of the same geographic origin (either European or Asiatic). However, specific effects, as great as the parental ones, occurred for hybrids from lines of different origins. Moreover, variability revealed for parental effects was greater within both European and Asiatic groups than in the mixed one. Key words: heterosis, genetic distance, geographic origin, genetic parameters, Brassica napus L.
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Lessmark, Anna, Gad Hatem, Györgyi Kovacs, Marta Vitai, Emma Ahlqvist, Tiinamaija Tuomi, Laszlo Koranyi, Leif Groop et Rashmi B. Prasad. « Lipid-Associated Variants near ANGPTL3 and LPL Show Parent-of-Origin Specific Effects on Blood Lipid Levels and Obesity ». Genes 13, no 1 (29 décembre 2021) : 91. http://dx.doi.org/10.3390/genes13010091.
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Parent-of-origin effects (POE) and sex-specific parental effects have been reported for plasma lipid levels, and a strong relationship exists between dyslipidemia and obesity. We aim to explore whether genetic variants previously reported to have an association to lipid traits also show POE on blood lipid levels and obesity. Families from the Botnia cohort and the Hungarian Transdanubian Biobank (HTB) were genotyped for 12 SNPs, parental origin of alleles were inferred, and generalized estimating equations were modeled to assess parental-specific associations with lipid traits and obesity. POE were observed for the variants at the TMEM57, DOCK7/ANGPTL3, LPL, and APOA on lipid traits, the latter replicated in HTB. Sex-specific parental effects were also observed; variants at ANGPTL3/DOCK7 showed POE on lipid traits and obesity in daughters only, while those at LPL and TMEM57 showed POE on lipid traits in sons. Variants at LPL and DOCK7/ANGPTL3 showed POE on obesity-related traits in Botnia and HTB, and POE effects on obesity were seen to a higher degree in daughters. This highlights the need to include analysis of POEs in genetic studies of complex traits.
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Satyaki, Prasad R. V., et Mary Gehring. « RNA Pol IV induces antagonistic parent-of-origin effects on Arabidopsis endosperm ». PLOS Biology 20, no 4 (7 avril 2022) : e3001602. http://dx.doi.org/10.1371/journal.pbio.3001602.
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Gene expression in endosperm—a seed tissue that mediates transfer of maternal resources to offspring—is under complex epigenetic control. We show here that plant-specific RNA polymerase IV (Pol IV) mediates parental control of endosperm gene expression. Pol IV is required for the production of small interfering RNAs that typically direct DNA methylation. We compared small RNAs (sRNAs), DNA methylation, and mRNAs in Arabidopsis thaliana endosperm from heterozygotes produced by reciprocally crossing wild-type (WT) plants to Pol IV mutants. We find that maternally and paternally acting Pol IV induce distinct effects on endosperm. Loss of maternal or paternal Pol IV impacts sRNAs and DNA methylation at different genomic sites. Strikingly, maternally and paternally acting Pol IV have antagonistic impacts on gene expression at some loci, divergently promoting or repressing endosperm gene expression. Antagonistic parent-of-origin effects have only rarely been described and are consistent with a gene regulatory system evolving under parental conflict.
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Georgiades, P., C. Chierakul et A. C. Ferguson-Smith. « Parental origin effects in human trisomy for chromosome 14q : implications for genomic imprinting. » Journal of Medical Genetics 35, no 10 (1 octobre 1998) : 821–24. http://dx.doi.org/10.1136/jmg.35.10.821.
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Li, Yaojun, et Yizhang Zhao. « Double Disadvantages : A Study of Ethnic and Hukou Effects on Class Mobility in China (1996–2014) ». Social Inclusion 5, no 1 (28 mars 2017) : 5–19. http://dx.doi.org/10.17645/si.v5i1.857.
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This paper examines the ethnic and household registration system (<em>hukou</em>) effects on intergenerational social mobility for men in China. Using national representative surveys covering almost two decades (1996–2014), we assess both absolute and relative rates of mobility by ethnicity and <em>hukou</em> origin. With regard to absolute mobility, we find that minority men had significantly lower rates of total and upward mobility than Han men, and those from rural <em>hukou</em> origins faced more unfavourable chances. With regard to relative mobility, we find men of rural ethnic origins significantly less likely to inherit their parental positions. Even with parental and own educational qualifications and party memberships controlled for, we still find ethnic minority men of rural <em>hukou</em> origins behind others in access to professional-managerial positions. Overall, our findings suggest that the preferential policies have largely removed the ethnic differences in the urban sector but ethnic minority men from rural <em>hukou</em> origins are faced with double disadvantages: in addition to the inequality of opportunity rooted in the institutional divide which they share with the majority group from similar backgrounds, they face much greater inequalities in conditions, namely, in having poorer socio-economic and cultural resources.
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Yang, Chin Jian, Rajiv Sharma, Gregor Gorjanc, Sarah Hearne, Wayne Powell et Ian Mackay. « Origin Specific Genomic Selection : A Simple Process To Optimize the Favorable Contribution of Parents to Progeny ». G3: ; Genes|Genomes|Genetics 10, no 7 (19 mai 2020) : 2445–55. http://dx.doi.org/10.1534/g3.120.401132.
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Modern crop breeding is in constant demand for new genetic diversity as part of the arms race with genetic gain. The elite gene pool has limited genetic variation and breeders are trying to introduce novelty from unadapted germplasm, landraces and wild relatives. For polygenic traits, currently available approaches to introgression are not ideal, as there is a demonstrable bias against exotic alleles during selection. Here, we propose a partitioned form of genomic selection, called Origin Specific Genomic Selection (OSGS), where we identify and target selection on favorable exotic alleles. Briefly, within a population derived from a bi-parental cross, we isolate alleles originating from the elite and exotic parents, which then allows us to separate out the predicted marker effects based on the allele origins. We validated the usefulness of OSGS using two nested association mapping (NAM) datasets: barley NAM (elite-exotic) and maize NAM (elite-elite), as well as by computer simulation. Our results suggest that OSGS works well in its goal to increase the contribution of favorable exotic alleles in bi-parental crosses, and it is possible to extend the approach to broader multi-parental populations.
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Yama, Mark F., Stephanie L. Tovey, Bruce S. Fogas et Lisa A. Teegarden. « Joint Consequences of Parental Alcoholism and Childhood Sexual Abuse, and Their Partial Mediation by Family Environment ». Violence and Victims 7, no 4 (janvier 1992) : 313–25. http://dx.doi.org/10.1891/0886-6708.7.4.313.
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This study investigated the effects of childhood sexual abuse and parental alcoholism in a sample of university women. Current symptoms of anxiety and depression were measured together with retrospective reports of subjects’ families of origin. Using a 2X2 factorial design, main effects on symptoms were obtained for sexual abuse and parental alcoholism, but their interaction was not significant. With respect to family environment, a history of sexual abuse was associated with perceptions that families of origin had less cohesion, more conflict, less emphasis on moral-religious matters, less emphasis on achievement, and less of an orientation towards intellectual, cultural, and recreational pursuits. Similarly, subjects who had alcoholic parents reported less family cohesion, more conflict, and less emphasis on moral-religious matters. Results of analyses of co variance suggested that family environment was a mediator of current symptoms of anxiety, but not symptoms of depression.
Thèses sur le sujet "Parental origin effects"
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Gendre, Blandine. « Recherche agnostique d'effets génétiques non additifs à partir de données génétiques pan-génomiques : application à l'étude de facteurs de la coagulation ». Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0324.
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Les études d'association pan-génomiques (GWAS) ont révolutionné ces 15 dernières années la recherche en génétique humaine en permettant l'identification de milliers de variants génétiques associés à des maladies complexes comme les maladies cardiovasculaires et des traits biologiques comme des facteurs de la coagulation. Toutefois, ces études reposent principalement sur des modèles additifs qui ne permettent pas de capturer toute la complexité des mécanismes génétiques qui peuvent être mis en jeu. Les interactions entre gènes (épistasie), entre gènes et facteurs environnementaux ainsi que les effets épigénétiques dû à l’empreinte parentale, sont ainsi négligés. L'objectif principal de cette thèse est de détecter des effets génétiques non additifs dans des études d'association pan-génomiques sur les taux plasmatiques de 2 facteurs importants de la cascade de la coagulation : le facteur V et le facteur de Willebrand. Pour cela, une méthodologie statistique peu connue et reposant sur une modification du test de Brown-Forsythe a été utilisée dans plusieurs cohortes du consortium CHARGE. Cette méthodologie a permis d’identifier le locus PSKH2 comme nouvel acteur participant à la régulation des taux plasmatiques de Facteur V. L’application de cette stratégie de recherche aux taux plasmatiques de Facteur de Willebrand a mis en évidence les limites de la méthode en présence de plusieurs polymorphismes en déséquilibre de liaison et influençant le phénotype étudié. À l'avenir, il serait intéressant de poursuivre ces recherches en explorant d'autres facteurs de la coagulation et en utilisant d’autres méthodologies statistiques moins sujettes à l’influence du déséquilibre de liaison. Les études d’association pan-génomiques (GWAS) ont révolutionné ces 15 dernières années la recherche en génétique humaine en permettant l’identification de milliers de variants génétiques associés à des maladies complexes comme les maladies cardiovasculaires et des traits biologiques comme des facteurs de la coagulation. Toutefois, ces études reposent principalement sur des hypothèses d’effets génétiques additifs qui ne permettent pas de capturer toute la complexité des mécanismes génétiques qui peuvent être mis en jeu. Les interactions entre gènes (épistasie), entre gènes et facteurs environnementaux ainsi que les effets épigénétiques dus par exemple à l’empreinte parentale, sont ainsi négligés. L’objectif principal de cette thèse est de détecter des effets génétiques non additifs influençant les taux plasmatiques de 2 facteurs importants de la cascade de la coagulation : le Facteur V et le Facteur de von Willebrand, et ce à partir de données génétiques pan-génomiques. Pour cela, une méthodologie statistique peu connue et reposant sur une modification du test de Brown-Forsythe a été utilisée dans plusieurs cohortes du consortium CHARGE. Cette méthodologie a permis d’identifier le locus PSKH2 comme nouvel acteur participant à la régulation des taux plasmatiques de Facteur V. L’application de cette stratégie de recherche aux taux plasmatiques de Facteur de von Willebrand a mis en évidence les limites de la méthode en présence de plusieurs polymorphismes en déséquilibre de liaison et influençant le phénotype étudié. À l’avenir, il serait intéressant de poursuivre ces recherches en explorant d’autres facteurs de la coagulation et en utilisant d’autres méthodologies statistiques moins sujettes à l’influence du déséquilibre de liaisonGenome-wide association studies (GWAS) have revolutionized human genetics research over the past 15 years by enabling the identification of thousands of genetic variants associated with complex diseases, such as cardiovascular diseases, and biological traits, such as coagulation factors. However, these studies primarily rely on additive models, which do not capture the full complexity of genetic mechanisms that may be involved. Interactions between genes (epistasis), gene-environment interactions, and epigenetic effects such as those due to parental imprinting are thus neglected. The main objective of this thesis is to detect, from GWAS data, non-additive genetic effects on plasma levels of two important factors in the coagulation cascade: Factor V and von Willebrand Factor. To achieve this, a neglected statistical methodology based on a modification of the Brown-Forsythe test was applied in several cohorts from the CHARGE consortium. This methodology identified the PSKH2 locus as a novel player in the regulation of plasma Factor V levels. Applying this research strategy to von Willebrand Factor plasma levels highlighted the limitations of the method in the presence of multiple polymorphisms in linkage disequilibrium that influence the studied phenotype. In the future, it would be interesting to pursue this research by exploring other coagulation factors and using other statistical methodologies less subject to the influence of linkage disequilibrium
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herrera, Blanca M. « Parent-of-origin effects in multiple sclerosis transmission ». Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496913.
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Collick, Andrew. « On the effect of parental origin of chromosomes on mouse development ». Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305555.
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Rasevic, Nikola. « Maternal and Parent-of-Origin Effects on the Etiology of Orofacial Clefting ». Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42642.
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Objective: To investigate the association of previously reported single nucleotide
polymorphisms (SNPs) in relation to orofacial clefts and assess their interaction with
environmental factors.
Methods: Genome-wide SNP genotypes were obtained for case-parent triads from the
EUROCRAN and ITALCLEFT studies. Candidate SNPs were selected from a previous genome-wide association study (Shi et al., 2012) along with surrounding SNPS for a total of 2142 genotyped and imputed SNPs. A total of 411 case-parent triads and 25 case-parent dyads were analyzed using log-linear models to test for maternal and parent-of-origin effects along with their interaction with maternal smoking and maternal folic acid consumption.
Results: A significant association (q = 0.025) was detected for a region in the ATXN3 gene. This significance refers to the interaction between maternal periconceptional smoking and maternal genetic effects. Nominally significant associations in genes relating to the brain were also detected.
Conclusion: SNPs in the ATXN3 region warrant further investigation.
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Isles, Anthony Roger. « Investigations of parent of origin effects in the olfactory system ». Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621562.
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Ragsdale, Gillian. « Genomic imprinting and human cognition : parent-of-origin effects on behaviour ». Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611803.
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COSENTINI, ILARIA. « Electrophysiological and behavioral characterization of parent-of-origin effects in mice ». Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/939921.
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He, Feng, et 贺峰. « Detection of parent-of-origin effects and association in relation to aquantitative trait ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44921408.
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Xin, Mingming, Ruolin Yang, Yingyin Yao, Chuang Ma, Huiru Peng, Qixin Sun, Xiangfeng Wang et Zhongfu Ni. « Dynamic parent-of-origin effects on small interfering RNA expression in the developing maize endosperm ». BioMed Central, 2014. http://hdl.handle.net/10150/610088.
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Background:In angiosperms, the endosperm plays a crucial placenta-like role in that not only is it necessary for nurturing the embryo, but also regulating embryogenesis through complicated genetic and epigenetic interactions with other seed compartments and is the primary tissue in which genomic imprinting occurs.Results:We observed a gradual increase of paternal siRNA expression in the early stages of kernels and an expected 2:1 maternal to paternal ratio in 7-DAP endosperm via sequencing of small interfering RNA (siRNA) transcriptomes in developing kernels (0, 3 and 5 days after pollination (DAP)) and endosperms (7, 10 and 15 DAP) from the maize B73 and Mo17 reciprocal crosses. Additionally, 460 imprinted siRNA loci were identified in the endosperm, with the majority (456/460, 99.1%) being maternally expressed at 10 DAP. Moreover, 13 out of 29 imprinted genes harbored imprinted siRNA loci within their 2-kb flanking regions, a significant higher frequency than expected based on simulation analysis. Additionally, gene ontology terms of "response to auxin stimulus", "response to brassinosteroid stimulus" and "regulation of gene expression" were enriched with genes harboring 10-DAP specific siRNAs, whereas those of "nutrient reservoir activity", "protein localization to vacuole" and "secondary metabolite biosynthetic process" were enriched with genes harboring 15-DAP specific siRNAs.Conclusions:A subset of siRNAs subjected to imprinted expression pattern in maize developing endosperm, and they are likely correlated with certain imprinted gene expression. Additionally, siRNAs might influence nutrient uptake and allocation processes during maize endosperm development.
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Zhou, Jiyuan, et 周基元. « Single-marker and haplotype analyses for detecting parent-of-origin effects using family and pedigree data ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B4308543X.
Texte intégralLivres sur le sujet "Parental origin effects"
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Lu, Yao. Parental Migration and Well-Being of Left-Behind Children from a Comparative Perspective. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190265076.003.0006.
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Parent–child separation due to migration has become increasingly prominent in developing countries. This chapter first discusses a conceptual framework for understanding the effect of parental migration on children’s development through both a socioeconomic and a psychosocial process. The chapter further highlights the importance of a comparative perspective in understanding how parental migration affects children, suggesting that the field should move beyond the debate of whether children benefit or suffer to examining the circumstances under which children benefit or suffer from parental migration. The author identifies several factors that shape the relative balance of economic and psychosocial processes arising from parental migration and its overall impact: which member migrates (mother, father, both, or nonparent family members), which dimensions of child development are studied (education, cognitive, health, emotional or behavioral development), where migrant parents go (domestically or internationally), and the social and economic context of the origin community.
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Swanson, James M., L. Eugene Arnold, Peter S. Jensen, Stephen P. Hinshaw, Lily T. Hechtman, William E. Pelham, Laurence L. Greenhill et al. Long-term outcomes in the Multimodal Treatment study of Children with ADHD (the MTA). Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198739258.003.0034.
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This chapter describes the long-term outcomes in the Multimodal Treatment study of ADHD (MTA), which began in 1994 and ended in 2014. First, we provide a short history of the origin of the MTA. Second, we review the design as a 14-month randomized clinical trial and the transition to a long-term follow-up. Third, we present findings from 12 key publications describing outcomes in four stages of the MTA from childhood to adulthood. Fourth, we discuss how the final adult assessments of the MTA address critical issues about symptomatic persistence of ADHD, functional outcomes outside the parental home, and cost-benefit analyses of residual effects of treatment with medication.
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Meaney, Michael J., et Rachel Yehuda. Epigenetic Mechanisms and the Risk for PTSD. Sous la direction de Charles B. Nemeroff et Charles R. Marmar. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190259440.003.0017.
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This chapter discusses the epigenetic mechanisms involved in individual variation in and persistence of post-traumatic stress disorder (PTSD). Such mechanisms make it possible to trace vulnerability for PTSD to effects that predate development of PTSD. While some may be genetic in origin, others may involve parental stress occurring pre-conception, in utero changes in the maternal environment contributing to developmental programming, and childhood adversity, resulting in modifications of genes’ contribution to PTSD risk. The chapter discusses epigenetic alterations implicated in hypothalamic–pituitary–adrenal (HPA) function in PTSD that mark increased risk. Unlike the transient alterations in neural, endocrine, or immunological signals that follow exposure to trauma, certain epigenetic markers can be chemically stable over extended periods and can serve as a basis for understanding the persistence of PTSD symptoms. The chapter concludes with a discussion of how epigenetic modification may offer insights into future treatments for PTSD.
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Watson, Marilyn. Attachment Theory. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190867263.003.0002.
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The origins of attachment theory and the work of John Bowlby and Mary Ainsworth are described. Four types of child–parent attachment relationships—secure, insecure/anxious, insecure/ambivalent, and insecure/disorganized—are outlined along with the ways each type might manifest itself in the classroom. A longitudinal study, conducted by Alan Sroufe and his colleagues, of the development and effects on learning and interpersonal relationships of different child–parent attachment relationships is described. Teachers too have a history of attachment relationships that can affect how they relate to their students. The chapter describes adult attachment and how one’s attachment history might, positively or negatively, affect one’s ability to build positive, nurturing relationships with students. Specific examples of ways teachers can offset the negative effects of a student’s or their own history of insecure attachment are described.
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Paul, Torremans. Part V Family Law, 27 Legitimacy, Legitimation and Adoption. Oxford University Press, 2017. http://dx.doi.org/10.1093/law/9780199678983.003.0027.
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This chapter examines the choice of law rules relating to legitimacy, legitimation and adoption, as well as rules governing the recognition of foreign adoptions and the jurisdiction of the English courts to make adoption orders. It begins with a discussion of questions surrounding legitimacy, such as legitimacy to be governed by the law of the domicile, the effect of the doctrine of putative marriage, meaning of ‘domicile of origin’, relevance of the incidents of status, and where birth to parents who are married does not confer legitimacy. It then considers legitimation by subsequent marriage and legitimation by recognition before turning to adoption proceedings in England, procedures for taking children into and out of the UK, and recognition of foreign adoptions. Finally, it analyses the effect of foreign adoptions by citing the relevant provisions of the Adoption and Children Act 2002.
Chapitres de livres sur le sujet "Parental origin effects"
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Blossfeld, Hans-Peter, Lydia Kleine, Nicole Luplow, Markus Nester et Monja Schmitt. « Educational Disparities Before and After the Transition from Primary to Secondary School in Germany : BiKS-8-18 Results on Differences in Children’s School Outcomes and Decision-Making Processes ». Dans Educational Processes, Decisions, and the Development of Competencies from Early Preschool Age to Adolescence, 281–304. Wiesbaden : Springer Fachmedien Wiesbaden, 2024. http://dx.doi.org/10.1007/978-3-658-43414-4_11.
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AbstractUsing data from BiKS-8-18 longitudinal cohort from Bavaria and Hesse, BiKS Project 5 focused on analyzing disparate educational trajectories and outcomes among students 8-18 years old. Applying Boudon’s (1974) theoretical distinction between primary and secondary effects of social origin, this chapter summarizes the results of the influence of social origin, social relations, and intra- and extrafamilial support on different dimensions of success at school, including competencies, grades, and school self-concept. The empirical findings demonstrate the centrality of intra-family and family-school relationships before and even after the transition to secondary school and the limited opportunities in Germany to correct earlier educational decisions in secondary school. The project also involved investigating the educational decision-making processes of parents (and older students) from different social backgrounds and teachers before and after the transition from primary to secondary school to shed light on Boudon’s secondary effects of social origin. In particular, the dynamic impacts of parental aspirations and the family’s social capital, educational costs, and probabilities of success on early tracking decisions were examined and proved to be relevant, albeit not for all social groups and situations.
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de la Casa-Esperón, Elena. « Nonmammalian Parent-of-Origin Effects ». Dans Methods in Molecular Biology, 277–94. Totowa, NJ : Humana Press, 2012. http://dx.doi.org/10.1007/978-1-62703-011-3_19.
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Blossfeld, Hans-Peter, et Markus Nester. « Differential School Trajectories and Educational Decisions of Migrants in Germany—Descriptive Results and Theoretical Explanations ». Dans Educational Processes, Decisions, and the Development of Competencies from Early Preschool Age to Adolescence, 305–26. Wiesbaden : Springer Fachmedien Wiesbaden, 2024. http://dx.doi.org/10.1007/978-3-658-43414-4_12.
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Abstract BiKS Project 7 investigates the mechanisms of disparities in educational success by migration background, especially among students from Turkey, before and after the transition from primary to secondary school in Germany. Using data from the BiKS-8-18 cohort, educational disparities between children with and without an immigrant background were empirically examined using the theoretical distinction between primary and secondary effects of social origin developed by Boudon. The results of the project show that the importance and mechanisms of primary and secondary effects on educational participation differ between students with and without immigrant background. On the one hand, the primary effect of social origin is much stronger for migrant children due to often insufficient German language skills, a lack of context-specific German cultural capital, and familial cultural capital that has lost at least some of its value due to migration. In contrast, the secondary effects of social origin are much weaker for migrant children: When children’s academic performance is controlled for, migrant children have a higher transition rate to upper secondary school, regardless of their social class of origin. Thus, migrant parents’ realization of more ambitious educational goals for their children (small secondary effect) is primarily hampered by their children’s poorer academic performance (strong primary effect).
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Stoilova, Rumiana, Ellen Boeren et Petya Ilieva-Trichkova. « Gender Gaps in Participation in Adult Education in Europe : Examining Factors and Barriers ». Dans Lifelong Learning, Young Adults and the Challenges of Disadvantage in Europe, 143–67. Cham : Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-14109-6_6.
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AbstractThis chapter asks how barriers to equal participation in adult education play out differently between (a) men and women and (b) women from different class and ethnic backgrounds. European Social Survey and Adult Education Survey data analyses confirm that low social origin is a significant barrier. Other socio-economic and socio-demographic characteristics can also act as barriers. The chapter draws attention to intersectionality: multiple simultaneous disadvantages, including gender (for women), social origin (for adults whose parents have basic or lower levels of education), and having an ethnic minority or migrant background. Women are less likely to receive financial support from their employer, though more likely to do so from public institutions. Ethnic minority status has a stronger negative effect for women than for men. Mediterranean and post-socialist welfare regimes reduce the effects of intersectionality less than social-democratic regimes.
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Rowe, Suzanne, Stephen Bishop et D. J. de Koning. « Imprinting in Genome Analysis : Modeling Parent-Of-Origin Effects in QTL Studies ». Dans Livestock Epigenetics, 113–29. Oxford, UK : Wiley-Blackwell, 2011. http://dx.doi.org/10.1002/9781119949930.ch7.
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Glaser, Rivka L., et Ian M. Morison. « Equality of the Sexes ? Parent-of-Origin Effects on Transcription and de novo Mutations ». Dans Bioinformatics for Systems Biology, 485–513. Totowa, NJ : Humana Press, 2009. http://dx.doi.org/10.1007/978-1-59745-440-7_26.
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Havermans, Nele, Gray Swicegood et Koenraad Matthijs. « Floor Effects or Compensation of Social Origin ? The Relation Between Divorce and Children’s School Engagement According to Parents’ Educational Level ». Dans European Studies of Population, 355–70. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-25838-2_17.
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Lee, Rennie, et Sin Yi Cheung. « Refugee Children in Australia : Wellbeing and Integration ». Dans Family Dynamics over the Life Course, 71–96. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-12224-8_5.
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AbstractWhether the children of immigrant populations, including refugees, integrate into the host society is a key challenge facing all countries with large immigrant populations. In Australia, this is crucial given rising numbers and anxieties over refugee settlement in recent decades. Forced migration and displacement due to violence, persecution, or natural disasters with families undertaking perilous journeys fleeing their homes often could mean a turning point and at the same time a stressful event that may have severe negative psychosocial and long-term effects. This can be particularly acute among refugee children, who are typically the least prepared to migrate, have experienced hardship associated with violence and persecution, and must grow up in a new country. From a life course perspective, the integration and wellbeing of refugee children is shaped by the timing and context of migration, including their age at migration and country of origin. In this chapter we draw on longitudinal data from Building a New Life in Australia (BNLA) to offer new evidence in our understanding of the integration and wellbeing of refugee children in Australia and policy recommendations to address the social disadvantages facing this population. Our findings indicate that refugee children are outperforming their parents, making intergenerational progress. However, we find some major differences by gender and national origin across a range of outcomes.
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Curley, James P. « Parent-of-Origin Effects on Parental Behavior ». Dans Neurobiology of the Parental Brain, 319–32. Elsevier, 2008. http://dx.doi.org/10.1016/b978-0-12-374285-8.00020-2.
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« Parental-Origin-Effect ». Dans Encyclopedia of Systems Biology, 1633. New York, NY : Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-9863-7_101108.
Texte intégralActes de conférences sur le sujet "Parental origin effects"
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Bedina Zavec, Apolonija. « Extracellular Vesicles for Cosmetic Applications ». Dans Socratic Lectures 8. University of Lubljana Press, 2023. http://dx.doi.org/10.55295/psl.2023.ii16.
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Extracellular vesicles (EVs) are nanosized membrane vesicles that carry membrane and cargo molecules inherited from their parental cells. Excellent delivery capacity, biological origin, and nanosized dimensions support the great potential of EVs as medical and cosmetic active ingredients. Many studies have already reported improved skin conditions by using EVs for skin rejuvenation, scar removal, and anti-pigmentation treatments. In this review, EVs from mesenchymal stem cells, platelets, skin microbiota, and microalgae will be considered. The most promising results come from mesenchymal stem cell (MSC) derived EVs that have impressive antiaging and wound-healing effects on the skin, but their use for medical or cosmetic purposes is not yet allowed in Europe and the United States. Autologous platelet- and extracellular vesicle-rich plasma (PVRP) is well tolerated and capable of rejuvenating the face; intradermal injections and topical applications are currently being considered in clinical and cosmetic dermatology. Symbiotic microorganisms of the human skin have many beneficial effects on the skin, but the presence of bacteria in cosmetic products is restricted; therefore, the preparation of EVs from skin-beneficial microbes is particularly relevant, and there are already many cosmetic products containing lysates from different probiotics on the market. Microalgae can produce many valuable bioactive compounds, antioxidants such as carotenoids are particularly interesting; therefore, microalgae are promising producers of EVs that could be used in cosmetic products. Keywords: Extracellular vesicles; Skin health; Microbiota; Mesenchymal stem cells; Micro-algae
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Jahnel, R. E., I. Blunk et N. Reinsch. « 662. Integrating parent-of-origin effects in random regression models for milk traits ». Dans World Congress on Genetics Applied to Livestock Production. The Netherlands : Wageningen Academic Publishers, 2022. http://dx.doi.org/10.3920/978-90-8686-940-4_662.
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Ganguly, Arupa, Tricia Bhatti, Karthik Ganapathy, Laura Conlin, Courtney MacMullen, Susan Becker, Eduardo Ruchelli et Charles Stanley. « Abstract 3293 : Molecular evidence for a parent of origin effect in pediatric insulinomas ». Dans Proceedings : AACR 106th Annual Meeting 2015 ; April 18-22, 2015 ; Philadelphia, PA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1538-7445.am2015-3293.
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Arshad, Syed Hasan, Wilfried Karmaus, Abid Raza, Sharon Matthews, Paula Williams, J. W. Holloway, Graham Roberts et Susan Ewart. « Parent Of Origin Effect In Childhood Asthma ; From Birth To 18 Years Of Age ». Dans American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado. American Thoracic Society, 2011. http://dx.doi.org/10.1164/ajrccm-conference.2011.183.1_meetingabstracts.a5476.
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Stoyanova, Stanislava. « Mental Resilience and State Anxiety in Bulgarians Living in Their country of Origin or Abroad During COVID-19 Pandemic ». Dans International Association of Cross Cultural Psychology Congress. International Association for Cross-Cultural Psychology, 2024. http://dx.doi.org/10.4087/rwks2555.
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Several major international comparative surveys (World Values Survey, East Asian Social Survey) have repeatedly shown that Chinese people report higher levels of general trust towards people than Japanese people. It has been pointed out that if Chinese people recall the people around them when answering the question “Most people can be trusted?”, this could explain their high general trust (Yoshino and Osaki, 2013), but there are no empirical studies yet. Therefore, in this study, we will compare general trust between Japan and China by focusing on “Who comes to mind in response”. A total of 318 Japanese and 476 Chinese university students were asked to answer questions about general trust, and to select from eight items such as “people in general,” “people in local area,” “friends and acquaintances,” and “parents, siblings, and relatives” as to whom they imaged when answering. The results showed that (1) Consistent with previous studies, Chinese people reported higher general trust (positive answer: 75.8%) than Japanese people (51.6%). (2) The percentage of people who only recalled “people in general” or “Japanese in general/Chinese in general” was higher in Japan (54.7%) than in China (22.3%), while the percentage of people who recalled “parents, siblings, and relatives” was higher in China (54.2%) than in Japan (16.4%). (3) In both Japan and China, the main effect of “the person who recalled” was significant, with those who recalled “parents, siblings, and relatives” having a higher general trust. (4)There was a significant interaction between “the people who recalled” and “culture” on general trust, and cultural differences in general trust were found only in the “people in general or Japanese in general/Chinese in general” condition, which is higher for Chinese than for Japanese. (5) The mediation effect of “the person who recalled” on the cultural difference in general trust was examined, and a significant partial mediation effect was identified. However, even considering these media effects, the cultural difference in general trust between Japan and China is still significant, suggesting that further investigation of other factors is needed. The results for the Japanese and Chinese in this study also indicate the need to treat responses to general trust in previous social surveys with caution and pay attention to the interpretation of cultural differences
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Tobias, Edward S., Phey M. Yeap, Eleni Mavraki, Alexander Fletcher, Marie E. Freel, Alexander Cooke, Nicola Bradshaw et al. « Abstract 3673 : Molecular analysis of pheochromocytoma aftermaternaltransmission ofSDHDmutation elucidates mechanism of parent-of-origin effect. » Dans Proceedings : AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012 ; Chicago, IL. American Association for Cancer Research, 2012. http://dx.doi.org/10.1158/1538-7445.am2012-3673.
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Grotmol, Tom, Robert Karlsson, Kristine Andreassen, Wenche Kristiansen, Elin Aschim, Roy Bremnes, Olav Dahl et al. « Abstract 1346 : Investigation of six testicular germ cell tumor susceptibility genes reveals a parent-of-origin effect inSPRY4. » Dans Proceedings : AACR 104th Annual Meeting 2013 ; Apr 6-10, 2013 ; Washington, DC. American Association for Cancer Research, 2013. http://dx.doi.org/10.1158/1538-7445.am2013-1346.
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Levon, Taylor, Kit Clemons, Ben Zapp et Tim Foltz. « A Multi-Disciplinary Approach for Well Spacing and Treatment Design Optimization in the Midland Basin Using Lateral Pore Pressure Estimation and Depletion Modeling ». Dans SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204195-ms.
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Abstract With a recent trend in increased infill well development in the Midland basin and other unconventional plays, it has been shown that depletion has a significant impact on hydraulic fracture propagation. This is largely because production drawdown causes in-situ stress changes, resulting in asymmetric fracture growth toward the depleted regions. In turn, this can have a negative impact on production capacity. For the initial part of this study, an infill child well was drilled and completed adjacent to a parent well that had been producing for two years. Due to drilling difficulties, the child well was steered to a new target zone located 125 feet above the original target. However, relative to the original target, treatment data from the new zone indicated abnormal treatment responses leading to a study to evaluate the source of these variations and subsequent mitigation. The initial study was conducted using a pore pressure estimation derived from drill bit geomechanics data to investigate depletion effects on the infill child well. The pore pressure results were compared to the child well treatment responses and bottom hole pressure measurements in the parent well. Following the initial study, additional hydraulic fracture modeling studies were conducted on a separate pad to investigate depletion around the infill wells, determine optimal well spacing for future wells given the level of depletion, and optimize treatment designs for future wells in similar depletion scenarios. A depletion model workflow was implemented based on integrating hydraulic fracture modeling and reservoir analytics for future infill pad development. The geomechanical properties were calibrated by DFIT results and pressure matching of the parent well treatments for the in-situ virgin conditions. Parent well fracture geometries were used in an RTA for an analytical approach of estimating drainage area of the parent wells. These were then applied to a depletion profile in the hydraulic fracture model for well spacing analysis and treatment design sensitivities. Results of the initial study indicated that stages in the new, higher interval had higher breakdown pressures than the lower interval. Additionally, the child well drilled in the lower interval had normal breakdown pressures in line with the parent well treatments. This suggests that treatment differences in the wells were ultimately due to depletion of the offset parent well. Based on the modeling efforts, optimal infill well spacing was determined based on the on-production time of the parent wells. The optimal treatment designs were also determined under the same conditions to minimize offset frac hits and unnecessary completion costs. This case study presents the use of a multi-disciplinary approach for well spacing and treatment optimization. The integration of a novel method of estimating pore pressure and depletion modeling workflows were used in an inventive way to understand depletion effects on future development.
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Adiguzel, Dr Osman. « Shape Reversibility and Energy Dissipation in Transformation Cycles in Shape Memory Alloys ». Dans 6th World Conference on Chemistry and Chemical Engineering and 6th World Conference on Advanced Materials, Nanoscience and Nanotechnology, 12. Eurasia Conferences, 2024. https://doi.org/10.62422/978-81-974314-2-5-001.
Texte intégralRésumé :
Shape memory alloys take place in a class of advanced smart materials by exhibiting a peculiar property called shape memory effect. This phenomenon is initiated with thermomechanical treatments on cooling and deformation and performed thermally on heating and cooling, with which shape of materials cycles between original and deformed shapes in reversible way. Therefore, this behavior can be called Thermoelasticity. This is plastic deformation with which strain energy is stored in the material and releases on heating by recovering original shape. This phenomenon is based on thermomechanical transformations, thermal and stress induced martensitic transformations. Thermal induced transformations are exothermic reactions and occur on cooling with the cooperative movement of atoms in {110} -type directions on {110}-type planes of austenite matrix, along with lattice twinning and ordered parent phase structures turn into twinned martensitic structure. Twinned structures turn into detwinned martensite by means of stress induced martensitic transformation with deformation. Also, reverse austenitic transformation is an endothermic austenitic transformation, and occurs on heating, and detwinned martensite structures turn into the ordered parent phase structure. These transformations are driven by lattice invariant shears. Martensitic and austenitic transformations are solid state transformation, and these transformations do not start at the equilibrium temperature at Gibbs Free Energy Temperature Diagram and a driving force is necessary for the transformations. These alloys exhibit another property called superelasticity, which is performed with stressing and releasing the material in elasticity limit at a constant temperature in parent phase region, and shape recovery occurs upon releasing, by exhibiting elastic material behavior. Stress-strain curve exhibit non-linear behavior, stressing and releasing paths are different, and hysteresis loop refers to the energy dissipation. Superelasticity is the result of stress-induced martensitic transformation, and parent phase structures turn into the completely detwinned martensite structures with stressing. Copper based alloys exhibit this property in metastable β-phase region, which has bcc-based structures. Lattice invariant shears and lattice twinning are not uniform in these alloys, and the ordered parent phase structures undergo long-period layered structures with martensitic transformation. These structures can be described by different unit cells as 3R, 9R or 18R depending on the stacking sequences on the close-packed planes of ordered lattice of parent phase. In the present contribution, x-ray diffraction and transmission electron microscopy studies were carried out on copper based CuZnAl and CuAlMn alloys. X-ray diffraction profiles and electron diffraction patterns exhibit super lattice reflections inherited from parent phase due to the displacive character of the transformation. X-ray diffractograms taken in a long-time interval show that diffraction angles and intensities of diffraction peaks change with the aging time at room temperature. This result refers to a new transformation in diffusive manner. Keywords: Shape memory effect, martensitic transformations, thermoelasticity, superelasticity, lattice twinning and detwinning.
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Hübelová, Dana, Nikola Mezihoráková, Beatrice Chromková et Alice Kozumplíková. « Sociální a ekonomická dimenze kvality života rodin chronicky nemocných dětských pacientů ». Dans XXIV. mezinárodního kolokvia o regionálních vědách. Brno : Masaryk University Press, 2021. http://dx.doi.org/10.5817/cz.muni.p210-9896-2021-65.
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Chronic diseases affect the quality of life of families of sick people on the level of their physical, economic, mental, and subjective well-being. The aim of the paper is two-folded: a) to determine the economic and social consequences of the child's illness for families and b) to identify the factors that may influence the origin and development of asthma in the child population. The data come from a survey we carried out on a sample of parents with children who are treated in the Children's Speleotherapy Sanatorium in Ostrov near Macocha (a total sample of 201 respondents). We checked for any association by use of correlation analysis, Kruskal-Wallis and Chi-square test. More than half of the families reported that the child's illness negatively influences the involvement in the labour market, families show an increase in financial costs associated with rehab and a financial loss during the care of a sick child. One third of the children’s patients has problems with missing classes at school, the average absence is 8 weeks in the school year, and every tenth child has difficulty in establishing social contacts. Analyses of external factors in relation to asthma show the effect of education on smoking in the family, but did not confirm the effect of age and mother's education on the birth weight of the child or the type of birth. From the results, it is clear that asthma adversely affects the quality of life of the asthmatic child and his family. The disease is thus associated with social and psychological consequences, which limits the performance at school for children and work activities for parents and other activities. All in one, it has not only health, but also socio-economic consequences.
Rapports d'organisations sur le sujet "Parental origin effects"
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Elías, Julio, Lucas Ronconi et Víctor Elías. Discrimination and Social Networks : Popularity among High School Students in Argentina. Inter-American Development Bank, août 2007. http://dx.doi.org/10.18235/0011263.
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The objective of this paper is to better understand peer popularity during adolescence and detect discrimination. The paper subsequently explores how student's characteristics affect their popularity. It is found that physically attractive students and with high academic performance are highly ranked by their peers, but the former effect is only significant in mixed schools, suggesting that is primarily driven by mating. Other traits, such as skin color, nationality and parental socioeconomic background do not affect peer popularity, although ethnic origin and parental education are statistically significant in some specifications. The findings are informative about discrimination in the school system. In particular, it appears that the unequal treatment based on race, wealth and nationality found in other social environments in Argentina is not observed among adolescents attending school.
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Singh, Anjali. Estimating the Chiasma Frequency in Diplotene-Diakinesis Stage. ConductScience, septembre 2020. http://dx.doi.org/10.55157/cs20200925.
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Chiasma is the point of crossing over or site where the exchange of genetic material takes place between two homologous, non-sister chromatids. The crossover occurs in the pachytene stage, however, it is observed in the diplotene stage of meiosis-I[2]. The cross-over between the two homologs also creates a new combination of parental genes, forming recombinants. The recombination of the genes causes variation in the population and exert a profound effect on genomic diversity and evolution. Meiotic recombination and variation in the population have been a concern for scientists to understand the impact and significance of crossing over in a population. Over time, various techniques, such as immunolocalization and electron microscopy of recombination nodules[2], were discovered for the analysis of meiotic recombination and quantification of crossing over. However, estimation of chiasma frequency is the traditional method followed widely to understand the phenomenon. Chiasma Frequency is defined as the estimation of the level of genetic recombination in a population. It is especially very effective to estimate the genetic recombination in organisms in which genetic analysis is impossible/difficult to perform[2]. So, this article is a layout of the origin of the concept of chiasmata, the factors affecting chiasma frequency, and its distribution in chromosomes. Also discussed, is the procedure for estimating chiasma frequency in plants as well as animals.
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Thomashow, Linda, Leonid Chernin, Ilan Chet, David M. Weller et Dmitri Mavrodi. Genetically Engineered Microbial Agents for Biocontrol of Plant Fungal Diseases. United States Department of Agriculture, 2005. http://dx.doi.org/10.32747/2005.7696521.bard.
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The objectives of the project were: a) to construct the site-specific integrative expression cassettes carrying: (i) the chiA gene for a 58-kDa endochitinase, (ii) the pyrrolnitrin biosynthesis operon, and (iii) the acdS gene encoding ACC deaminase; b) to employ these constructs to engineer stable recombinant strains with an expanded repertoire of beneficial activities; c) to evaluate the rhizosphere competence and antifungal activity of the WT and modified strains against pathogenic fungi under laboratory and greenhouse conditions; and d) to monitor the persistence and impact of the introduced strains on culturable and nonculturable rhizosphere microbial populations in the greenhouse and the field. The research generally support our concepts that combining strategically selected genes conferring diverse modes of action against plant pathogens into one organism can improve the efficacy of biological control agents. We hypothesized that biocontrol agents (BCAs) engineered to expand their repertoire of beneficial activities will more effectively control soilborne plant pathogens. In this work, we demonstrated that biocontrol activity of Pseudomonas fluorescens Q8r1-96 and Q2-87, both producing the antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) effective against the plant pathogenic fungus Rhizoctonia solani, can be improved significantly by introducing and expressing either the 1.6-kb gene chiA, encoding the 58-kDa endochitinase ChiA from the rhizosphere strain SerratiaplymuthicaIC1270, or the 5.8-kb prnABCDoperon encoding the broad-range antibiotic pyrrolnitrin (Prn) from another rhizosphere strain, P. fluorescens Pf-5. The PₜₐcchiAandPₜₐcprnABCDcassettes were cloned into the integrative pBK-miniTn7-ΩGm plasmid, and inserted into the genomic DNA of the recipient bacteria. Recombinant derivatives of strains Q8r1-96 and Q2-87 expressing the PₜₐcchiA or PₜₐcprnABCD cassettes produced endochitinase ChiA, or Prn, respectively, in addition to 2,4-DAPG, and the recombinants gave significantly better biocontrol of R. solani on beans under greenhouse conditions. The disease reduction index increased in comparison to the parental strains Q8r1-96 and Q2-87 to 17.5 and 39.0% from 3.2 and 12.4%, respectively, in the case of derivatives carrying the PₜₐcchiAcassette and to 63.1 and 70% vs. 2.8 and 12,4%, respectively, in the case of derivatives carrying the PₜₐcprnABCDcassette. The genetically modified strains exhibited persistence and non-target effects comparable to those of the parental strains in greenhouse soil. Three integrative cassettes carrying the acdS gene encoding ACC deaminase cloned under the control of different promoters were constructed and tested for enhancement of plant growth promotion by biocontrol strains of P. fluorescens and S. plymuthica. The integrative cassettes constructed in this work are already being used as a simple and efficient tool to improve biocontrol activity of various PGPR bacteria against fungi containing chitin in the cell walls or highly sensitive to Prn. Some parts of the work (e. g., construction of integrative cassettes) was collaborative while other parts e.g., (enzyme and antibiotic activity analyses) were fully synergistic. The US partners isolated and provided to the Israeli collaborators the original biocontrol strains P. fluorescens strains Q8r1-96 and Q2-87 and their mutants deficient in 2,4-DAPG production, which were used to evaluate the relative importance of introduction of Prn, chitinase or ACC deaminase genes for improvement of the biocontrol activity of the parental strains. The recombinant strains obtained at HUJI were supplied to the US collaborators for further analysis.
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Barg, Rivka, Kendal D. Hirschi, Avner Silber, Gozal Ben-Hayyim, Yechiam Salts et Marla Binzel. Combining Elevated Levels of Membrane Fatty Acid Desaturation and Vacuolar H+ -pyrophosphatase Activity for Improved Drought Tolerance. United States Department of Agriculture, décembre 2012. http://dx.doi.org/10.32747/2012.7613877.bard.
Texte intégralRésumé :
Background to the topic: In previous works we have shown that Arabidopsis and tomato over-expressing H+-pyrophosphatase show increased tolerance to drought imposed by withholding irrigation of young plants in pots (Park et al. 2005). In addition, young tobacco plants over-expressing fatty acid desaturase 3 (OEX-FAD3) also showed increasing tolerance to drought stress (Zhang et al 2005), and similarly OEX-FAD3 young tomato plants (unpublished data from ARO), hence raising the possibility that pyramiding the two could further improve drought tolerance in tomato. Based on these findings the specific objects originally set were: 1. To analyze the impact of pyramiding transgenes for enhanced fatty acid desaturation and for elevated H+-PPase activity on tomato yielding under water deficit stress conditions. 2. To elucidate the biochemical relationship between elevated desaturation of the membrane lipids and the activities of selected vacuolar transporters in the context of drought responses. 3. To explore the S. pennellii introgression lines as alternative genetic sources for drought tolerance related to enhanced fatty acid desaturation and/or H+-PPase activity. 4. Since OEX-FAD3 increases the levels of linolenic acid which is the precursor of various oxylipins including the stress hormone Jasmonate. (JA), study of the effect of this transgene on tolerance to herbivore pests was added as additional goal. The Major conclusions, solutions, and achievements are: (1) The facts that ectopic over-expression of vacuolarH+-PPases (in line OEX-AVP1) does not change the fatty acid profile compared to the parental MoneyMaker (MM) line and that elevated level of FA desaturation (by OEX-FAD3) does not change the activity of either H+-PPase, H+-ATPaseor Ca2+ /H+ antiport, indicate that the observed increased drought tolerance reported before for increase FA desaturation in tobacco plants and increased H+PPase in tomato plants involves different mechanisms. (2) After generating hybrid lines bringing to a common genetic background (i.e. F1 hybrids between line MP-1 and MM) each of the two transgenes separately and the two transgenes together the effect of various drought stress regimes including recovery from a short and longer duration of complete water withhold as well as performance under chronic stresses imposed by reducing water supply to 75-25% of the control irrigation regime could be studied. Under all the tested conditions in Israel, for well established plants grown in 3L pots or larger, none of the transgenic lines exhibited a reproducible significantly better drought tolerance compare to the parental lines. Still, examining the performance of these hybrids under the growth practices followed in the USA is called for. (3) Young seedlings of none of the identified introgression lines including the S. pennellii homologs of two of the H+-PPase genes and one of the FAD7 genes performed better than line M82 upon irrigation withhold. However, differences in the general canopy structures between the IL lines and M82 might mask such differences if existing. (4). Over-expression of FAD3 in the background of line MP-1 was found to confer significant tolerance to three important pest insects in tomato: Bordered Straw (Heliothis peltigera), Egyptian cotton leafworm (Spodoptera littoralis) and Western Flower Thrips (Frankliniella occidentalis). Implications: Although the original hypothesis that pyramiding these two trasgenes could improve drought tolerance was not supported, the unexpected positive impact on herbivore deterring, as well as the changes in dynamics of JA biosynthesis in response to wounding and the profound changes in expression of wound response genes calls for deciphering the exact linolenic acid derived signaling molecule mediating this response. This will further facilitate breeding for herbivore pest and mechanical stress tolerance based on this pathway.
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Fridman, Eyal, Jianming Yu et Rivka Elbaum. Combining diversity within Sorghum bicolor for genomic and fine mapping of intra-allelic interactions underlying heterosis. United States Department of Agriculture, janvier 2012. http://dx.doi.org/10.32747/2012.7597925.bard.
Texte intégralRésumé :
Heterosis, the enigmatic phenomenon in which whole genome heterozygous hybrids demonstrate superior fitness compared to their homozygous parents, is the main cornerstone of modern crop plant breeding. One explanation for this non-additive inheritance of hybrids is interaction of alleles within the same locus. This proposal aims at screening, identifying and investigating heterosis trait loci (HTL) for different yield traits by implementing a novel integrated mapping approach in Sorghum bicolor as a model for other crop plants. Originally, the general goal of this research was to perform a genetic dissection of heterosis in a diallel built from a set of Sorghum bicolor inbred lines. This was conducted by implementing a novel computational algorithm which aims at associating between specific heterozygosity found among hybrids with heterotic variation for different agronomic traits. The initial goals of the research are: (i) Perform genotype by sequencing (GBS) of the founder lines (ii) To evaluate the heterotic variation found in the diallel by performing field trails and measurements in the field (iii) To perform QTL analysis for identifying heterotic trait loci (HTL) (iv) to validate candidate HTL by testing the quantitative mode of inheritance in F2 populations, and (v) To identify candidate HTL in NAM founder lines and fine map these loci by test-cross selected RIL derived from these founders. The genetic mapping was initially achieved with app. 100 SSR markers, and later the founder lines were genotyped by sequencing. In addition to the original proposed research we have added two additional populations that were utilized to further develop the HTL mapping approach; (1) A diallel of budding yeast (Saccharomyces cerevisiae) that was tested for heterosis of doubling time, and (2) a recombinant inbred line population of Sorghum bicolor that allowed testing in the field and in more depth the contribution of heterosis to plant height, as well as to achieve novel simulation for predicting dominant and additive effects in tightly linked loci on pseudooverdominance. There are several conclusions relevant to crop plants in general and to sorghum breeding and biology in particular: (i) heterosis for reproductive (1), vegetative (2) and metabolic phenotypes is predominantly achieved via dominance complementation. (ii) most loci that seems to be inherited as overdominant are in fact achieving superior phenotype of the heterozygous due to linkage in repulsion, namely by pseudooverdominant mechanism. Our computer simulations show that such repulsion linkage could influence QTL detection and estimation of effect in segregating populations. (iii) A new height QTL (qHT7.1) was identified near the genomic region harboring the known auxin transporter Dw3 in sorghum, and its genetic dissection in RIL population demonstrated that it affects both the upper and lower parts of the plant, whereas Dw3 affects only the part below the flag leaf. (iv) HTL mapping for grain nitrogen content in sorghum grains has identified several candidate genes that regulate this trait, including several putative nitrate transporters and a transcription factor belonging to the no-apical meristem (NAC)-like large gene family. This activity was combined with another BARD-funded project in which several de-novo mutants in this gene were identified for functional analysis.
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Aharoni, Asaph, Zhangjun Fei, Efraim Lewinsohn, Arthur Schaffer et Yaakov Tadmor. System Approach to Understanding the Metabolic Diversity in Melon. United States Department of Agriculture, juillet 2013. http://dx.doi.org/10.32747/2013.7593400.bard.
Texte intégralRésumé :
Fruit quality is determined by numerous genetic factors that affect taste, aroma, color, texture, nutritional value and shelf life. To unravel the genetic components involved in the metabolic pathways behind these traits, the major goal of the project was to identify novel genes that are involved in, or that regulate, these pathways using correlation analysis between genotype, metabolite and gene expression data. The original and specific research objectives were: (1) Collection of replicated fruit from a population of 96 RI lines derived from parents distinguished by great diversity in fruit development and quality phenotypes, (2) Phenotypic and metabolic profiling of mature fruit from all 96 RI lines and their parents, (3) 454 pyrosequencing of cDNA representing mRNA of mature fruit from each line to facilitate gene expression analysis based on relative EST abundance, (4) Development of a database modeled after an existing database developed for tomato introgression lines (ILs) to facilitate online data analysis by members of this project and by researchers around the world. The main functions of the database will be to store and present metabolite and gene expression data so that correlations can be drawn between variation in target traits or metabolites across the RI population members and variation in gene expression to identify candidate genes which may impact phenotypic and chemical traits of interest, (5) Selection of RI lines for segregation and/or hybridization (crosses) analysis to ascertain whether or not genes associated with traits through gene expression/metabolite correlation analysis are indeed contributors to said traits. The overall research strategy was to utilize an available recombinant inbred population of melon (Cucumis melo L.) derived from phenotypically diverse parents and for which over 800 molecular markers have been mapped for the association of metabolic trait and gene expression QTLs. Transcriptomic data were obtained by high throughput sequencing using the Illumina platform instead of the originally planned 454 platform. The change was due to the fast advancement and proven advantages of the Illumina platform, as explained in the first annual scientific report. Metabolic data were collected using both targeted (sugars, organic acids, carotenoids) and non-targeted metabolomics analysis methodologies. Genes whose expression patterns were associated with variation of particular metabolites or fruit quality traits represent candidates for the molecular mechanisms that underlie them. Candidate genes that may encode enzymes catalyzingbiosynthetic steps in the production of volatile compounds of interest, downstream catabolic processes of aromatic amino acids and regulatory genes were selected and are in the process of functional analyses. Several of these are genes represent unanticipated effectors of compound accumulation that could not be identified using traditional approaches. According to the original plan, the Cucurbit Genomics Network (http://www.icugi.org/), developed through an earlier BARD project (IS-3333-02), was expanded to serve as a public portal for the extensive metabolomics and transcriptomic data resulting from the current project. Importantly, this database was also expanded to include genomic and metabolomic resources of all the cucurbit crops, including genomes of cucumber and watermelon, EST collections, genetic maps, metabolite data and additional information. In addition, the database provides tools enabling researchers to identify genes, the expression patterns of which correlate with traits of interest. The project has significantly expanded the existing EST resource for melon and provides new molecular tools for marker-assisted selection. This information will be opened to the public by the end of 2013, upon the first publication describing the transcriptomic and metabolomics resources developed through the project. In addition, well-characterized RI lines are available to enable targeted breeding for genes of interest. Segregation of the RI lines for specific metabolites of interest has been shown, demonstrating the utility in these lines and our new molecular and metabolic data as a basis for selection targeting specific flavor, quality, nutritional and/or defensive compounds. To summarize, all the specific goals of the project have been achieved and in many cases exceeded. Large scale trascriptomic and metabolomic resources have been developed for melon and will soon become available to the community. The usefulness of these has been validated. A number of novel genes involved in fruit ripening have been selected and are currently being functionally analyzed. We thus fully addressed our obligations to the project. In our view, however, the potential value of the project outcomes as ultimately manifested may be far greater than originally anticipated. The resources developed and expanded under this project, and the tools created for using them will enable us, and others, to continue to employ resulting data and discoveries in future studies with benefits both in basic and applied agricultural - scientific research.
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Bennett, Alan B., Arthur A. Schaffer, Ilan Levin, Marina Petreikov et Adi Doron-Faigenboim. Manipulating fruit chloroplasts as a strategy to improve fruit quality. United States Department of Agriculture, janvier 2013. http://dx.doi.org/10.32747/2013.7598148.bard.
Texte intégralRésumé :
The Original Objectives were modified and two were eliminated to reflect the experimental results: Objective 1 - Identify additional genetic variability in SlGLK2 and IPin wild, traditional and heirloom tomato varieties Objective 2 - Determine carbon balance and horticultural characteristics of isogenic lines expressing functional and non-functional alleles of GLKsand IP Background: The goal of the research was to understand the unique aspects of chloroplasts and photosynthesis in green fruit and the consequences of increasing the chloroplast capacity of green fruit for ripe fruit sugars, yield, flavor and nutrient qualities. By focusing on the regulation of chloroplast formation and development solely in fruit, our integrated knowledge of photosynthetic structures/organs could be broadened and the results of the work could impact the design of manipulations to optimize quality outputs for the agricultural fruit with enhanced sugars, nutrients and flavors. The project was based on the hypothesis that photosynthetic and non-photosynthetic plastid metabolism in green tomato fruit is controlled at a basal level by light for minimal energy requirements but fruit-specific genes regulate further development of robust chloroplasts in this organ. Our BARD project goals were to characterize and quantitate the photosynthesis and chloroplast derived products impacted by expression of a tomato Golden 2- like 2 transcription factor (US activities) in a diverse set of 31 heirloom tomato lines and examine the role of another potential regulator, the product of the Intense Pigment gene (IP activities). Using tomato Golden 2-like 2 and Intense Pigment, which was an undefined locus that leads to enhanced chloroplast development in green fruit, we sought to determine the benefits and costs of extensive chloroplast development in fruit prior to ripening. Major conclusions, solutions, achievements: Single nucleotide polymorphisms in the promoter, coding and intronicSlGLK2 sequences of 20 heirloom tomato lines were identified and three SlGLK2 promoter lineages were identified; two lineages also had striped fruit variants. Lines with striped fruit but no shoulders were not identified. Green fruit chlorophyll and ripe fruit soluble sugar levels were measured in 31 heirloom varieties and fruit size correlates with ripe fruit sugars but dark shoulders does not. A combination of fine mapping, recombinant generation, RNAseq expression and SNP calling all indicated that the proposed localization of a single locus IP on chr 10 was incorrect. Rather, the IP line harbored 11 separate introgressions from the S. chmielewskiparent, scattered throughout the genome. These introgressions harbored ~3% of the wild species genome and no recombinant consistently recovered the IP parental phenotype. The 11 introgressions were dissected into small combinations in segregating recombinant populations. Based on these analyses two QTL for Brix content were identified, accounting for the effect of increased Brix in the IP line. Scientific and agricultural implications: SlGLK2 sequence variation in heirloom tomato varieties has been identified and can be used to breed for differences in SlGLK2 expression and possibly in the green striped fruit phenotype. Two QTL for Brix content have been identified in the S. chmielewskiparental line and these can be used for increasing soluble solids contents in breeding programs.
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Meir, Shimon, Michael S. Reid, Cai-Zhong Jiang, Amnon Lers et Sonia Philosoph-Hadas. Molecular Studies of Postharvest Leaf and Flower Senescence. United States Department of Agriculture, janvier 2011. http://dx.doi.org/10.32747/2011.7592657.bard.
Texte intégralRésumé :
Original objectives: To understand the regulation of abscission by exploring the nature of changes of auxin-related gene expression in tomato (Lycopersicon esculatumMill) abscission zones (AZs) following organ removal, and by analyzing the function of these genes. Our specific goals were: 1) To complete the microarray analyses in tomato flower and leaf AZs, for identifying genes whose expression changes early in response to auxin depletion; 2) To examine, using virus-induced gene silencing (VIGS), the effect of silencing target genes on ethylene sensitivity and abscission competence of the leaf and flower AZs; 3) To isolate and characterize promoters from AZ-specific genes to be used in functional analysis; 4) To generate stable transgenic tomato plants with selected genes silenced with RNAi, under the control of an AZ-specific promoter, for further characterization of their abscission phenotypes. Background: Abscission, the separation of organs from the parent plant, results in postharvest quality loss in many ornamentals and other fresh produce. The process is initiated by changes in the auxin gradient across the AZ, and is triggered by ethylene. Although changes in gene expression have been correlated with the ethylene-mediated execution of abscission, there is almost no information on the initiation of the abscission process, as the AZ becomes sensitized to ethylene. The present project was focused on elucidating these early molecular regulatory events, in order to gain a better control of the abscission process for agricultural manipulations. Major conclusions, solutions, achievements: Microarray analyses, using the Affymetrix Tomato GeneChip®, revealed changes in expression, occurring early in abscission, of many genes with possible regulatory functions. These included a range of auxin- and ethylene-related transcription factors (TFs), other TFs that are transiently induced just after flower removal, and a set of novel AZ-specific genes. We also identified four different defense-related genes, including: Cysteine-type endopeptidase, α- DOX1, WIN2, and SDF2, that are newly-associated with the late stage of the abscission process. This supports the activation of different defense responses and strategies at the late abscission stages, which may enable efficient protection of the exposed tissue toward different environmental stresses. To facilitate functional studies we implemented an efficient VIGS system in tomato, and isolated two abscission-specific promoters (pTAPG1 and pTAPG4) for gene silencing in stable transformation. Using the VIGS system we could demonstrate the importance of TAPGs in abscission of tomato leaf petioles, and evaluated the importance of more than 45 genes in abscission. Among them we identified few critical genes involved in leaf and flower abscission. These included: PTRP-F1, PRP, TKN4, KNOTTED-like homeobox TF, KD1, and KNOX-like homeodomain protein genes, the silencing of which caused a striking retardation of pedicel abscission, and ERF1, ERF4, Clavata-like3 protein, Sucrose transporter protein, and IAA10 genes, the silencing of which delayed petiole abscission. The importance of PRPand KD1 genes in abscission was confirmed also by antisense–silencing using pTAPG4. Experiments testing the effects of RNAi silencing of few other genes are still in progress, The analysis of the microarray results of flower and leaf AZs allowed us to establish a clear sequence of events occurring during acquisition of tissue sensitivity to ethylene, and to confirm our hypothesis that acquisition of ethylene sensitivity in the AZ is associated with altered expression of auxin-regulated genes in both AZs. Implication, both scientific and agricultural: Our studies had provided new insights into the regulation of the abscission process, and shaded light on the molecular mechanisms that drive the acquisition of abscission competence in the AZ. We pointed out some critical genes involved in regulation of abscission, and further expanded our knowledge of auxin-ethylene cross talk during the abscission process. This permits the development of novel techniques for manipulating abscission, and thereby improving the postharvest performance of ornamentals and other crops.
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Ohad, Nir, et Robert Fischer. Regulation of Fertilization-Independent Endosperm Development by Polycomb Proteins. United States Department of Agriculture, janvier 2004. http://dx.doi.org/10.32747/2004.7695869.bard.
Texte intégralRésumé :
Arabidopsis mutants that we have isolated, encode for fertilization-independent endosperm (fie), fertilization-independent seed2 (fis2) and medea (mea) genes, act in the female gametophyte and allow endosperm to develop without fertilization when mutated. We cloned the FIE and MEA genes and showed that they encode WD and SET domain polycomb (Pc G) proteins, respectively. Homologous proteins of FIE and MEA in other organisms are known to regulate gene transcription by modulating chromatin structure. Based on our results, we proposed a model whereby both FIE and MEA interact to suppress transcription of regulatory genes. These genes are transcribed only at proper developmental stages, as in the central cell of the female gametophyte after fertilization, thus activating endosperm development. To test our model, the following questions were addressed: What is the Composition and Function of the Polycomb Complex? Molecular, biochemical, genetic and genomic approaches were offered to identify members of the complex, analyze their interactions, and understand their function. What is the Temporal and Spatial Pattern of Polycomb Proteins Accumulation? The use of transgenic plants expressing tagged FIE and MEA polypeptides as well as specific antibodies were proposed to localize the endogenous polycomb complex. How is Polycomb Protein Activity Controlled? To understand the molecular mechanism controlling the accumulation of FIE protein, transgenic plants as well as molecular approaches were proposed to determine whether FIE is regulated at the translational or posttranslational levels. The objectives of our research program have been accomplished and the results obtained exceeded our expectation. Our results reveal that fie and mea mutations cause parent-of-origin effects on seed development by distinct mechanisms (Publication 1). Moreover our data show that FIE has additional functions besides controlling the development of the female gametophyte. Using transgenic lines in which FIE was not expressed or the protein level was reduced during different developmental stages enabled us for the first time to explore FIE function during sporophyte development (Publication 2 and 3). Our results are consistent with the hypothesis that FIE, a single copy gene in the Arabidopsis genome, represses multiple developmental pathways (i.e., endosperm, embryogenesis, shot formation and flowering). Furthermore, we identified FIE target genes, including key transcription factors known to promote flowering (AG and LFY) as well as shoot and leaf formation (KNAT1) (Publication 2 and 3), thus demonstrating that in plants, as in mammals and insects, PcG proteins control expression of homeobox genes. Using the Yeast two hybrid system and pull-down assays we demonstrated that FIE protein interact with MEA via the N-terminal region (Publication 1). Moreover, CURLY LEAF protein, an additional member of the SET domain family interacts with FIE as well. The overlapping expression patterns of FIE, with ether MEA or CLF and their common mutant phenotypes, demonstrate the versatility of FIE function. FIE association with different SET domain polycomb proteins, results in differential regulation of gene expression throughout the plant life cycle (Publication 3). In vitro interaction assays we have recently performed demonstrated that FIE interacts with the cell cycle regulatory component Retinobalsoma protein (pRb) (Publication 4). These results illuminate the potential mechanism by which FIE may restrain embryo sac central cell division, at least partly, through interaction with, and suppression of pRb-regulated genes. The results of this program generated new information about the initiation of reproductive development and expanded our understanding of how PcG proteins regulate developmental programs along the plant life cycle. The tools and information obtained in this program will lead to novel strategies which will allow to mange crop plants and to increase crop production.