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Maintenance of Genome Integrity: DNA Damage Sensing, Signaling, Repair and Replication in Plants

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198207 Year: Pages: 129 DOI: 10.3389/978-2-88919-820-7 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-01-19 14:05:46
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Environmental stresses and metabolic by-products can severely affect the integrity of genetic information by inducing DNA damage and impairing genome stability. As a consequence, plant growth and productivity are irreversibly compromised. To overcome genotoxic injury, plants have evolved complex strategies relying on a highly efficient repair machinery that responds to sophisticated damage perception/signaling networks. The DNA damage signaling network contains several key components: DNA damage sensors, signal transducers, mediators, and effectors. Most of these components are common to other eukaryotes but some features are unique to the plant kingdom. ATM and ATR are well-conserved members of PIKK family, which amplify and transduce signals to downstream effectors. ATM primarily responds to DNA double strand breaks while ATR responds to various forms of DNA damage. The signals from the activated transducer kinases are transmitted to the downstream cell-cycle regulators, such as CHK1, CHK2, and p53 in many eukaryotes. However, plants have no homologue of CHK1, CHK2 nor p53. The finding of Arabidopsis transcription factor SOG1 that seems functionally but not structurally similar to p53 suggests that plants have developed unique cell cycle regulation mechanism. The double strand break repair, recombination repair, postreplication repair, and lesion bypass, have been investigated in several plants. The DNA double strand break, a most critical damage for organisms are repaired non-homologous end joining (NHEJ) or homologous recombination (HR) pathway. Damage on template DNA makes replication stall, which is processed by translesion synthesis (TLS) or error-free postreplication repair (PPR) pathway. Deletion of the error-prone TLS polymerase reduces mutation frequencies, suggesting PPR maintains the stalled replication fork when TLS is not available. Unveiling the regulation networks among these multiple pathways would be the next challenge to be completed. Some intriguing issues have been disclosed such as the cross-talk between DNA repair, senescence and pathogen response and the involvement of non-coding RNAs in global genome stability. Several studies have highlighted the essential contribution of chromatin remodeling in DNA repair. DNA damage sensing, signaling and repair have been investigated in relation to environmental stresses, seed quality issues, mutation breeding in both model and crop plants and all these studies strengthen the idea that components of the plant response to genotoxic stress might represent tools to improve stress tolerance and field performance. This focus issue gives researchers the opportunity to gather and interact by providing Mini-Reviews, Commentaries, Opinions, Original Research and Method articles which describe the most recent advances and future perspectives in the field of DNA damage sensing, signaling and repair in plants. A comprehensive overview of the current progresses dealing with the genotoxic stress response in plants will be provided looking at cellular and molecular level with multidisciplinary approaches. This will hopefully bring together valuable information for both plant biotechnologists and breeders.

Grappling with the Multifaceted World of the DNA Damage Response

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450572 Year: Pages: 306 DOI: 10.3389/978-2-88945-057-2 Language: English
Publisher: Frontiers Media SA
Subject: Genetics --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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DNA damage is a major threat to genomic integrity and cell survival. It can arise both spontaneously and in response to exogenous agents. DNA damage can attack most parts of the DNA structure, ranging from minor and major chemical modifications, to single-strand breaks (SSBs) and gaps, to full double-strand breaks (DSBs). If DNA injuries are mis-repaired or unrepaired, they may ultimately result in mutations or wider-scale genome aberrations that threaten cell homeostasis. Consequently, the cells elicit an elaborate signalling network, known as DNA damage response (DDR), to detect and repair these cytotoxic lesions. This Research Topic was aimed at comprehensive investigations of basic and novel mechanisms that underlie the DNA damage response in eukaryotes.DNA damage is a major threat to genomic integrity and cell survival. It can arise both spontaneously and in response to exogenous agents. DNA damage can attack most parts of the DNA structure, ranging from minor and major chemical modifications, to single-strand breaks (SSBs) and gaps, to full double-strand breaks (DSBs). If DNA injuries are mis-repaired or unrepaired, they may ultimately result in mutations or wider-scale genome aberrations that threaten cell homeostasis. Consequently, the cells elicit an elaborate signalling network, known as DNA damage response (DDR), to detect and repair these cytotoxic lesions. This Research Topic was aimed at comprehensive investigations of basic and novel mechanisms that underlie the DNA damage response in eukaryotes.

Research Methods Pedagogy: Engaging Psychology Students in Research Methods and Statistics

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450107 Year: Pages: 102 DOI: 10.3389/978-2-88945-010-7 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Psychology
Added to DOAB on : 2018-02-27 16:16:44
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Research methods and statistics are central to the development of professional competence and evidence based psychological practice. Furthermore, the ability to interpret and apply research findings contributes to the development of psychological literacy, the primary outcome of an undergraduate education in psychology. Despite this, many psychology students express little interest in, and in some cases an active dislike of, learning research methods and statistics. This ebook brings together current research, innovative evidence-based practice and critical discourse related to engaging psychology students in learning quantitative and qualitative mixed methods research.

Deciphering serotonin's role in neurodevelopment

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192762 Year: Pages: 131 DOI: 10.3389/978-2-88919-276-2 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2015-12-03 13:02:24
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One of the most challenging questions in neurobiology to tackle is how the serotonergic system steers neurodevelopment. With the increase in serotonergic anxiolytic and antidepressant drugs, serotonin was thought to signal adversity or to serve as an emotional signal. However, a vast amount of literature is accumulating showing that serotonin rather mediates neuroplasticity and plays a key role in early developmental processes. For instance, selective serotonin reuptake inhibitors (SSRIs), serving as antidepressants, increase neurogenesis and trigger autism-related brain and behavioural changes during embryonic and perinatal exposure. Moreover, serotonin transporter gene variation is associated with alterations in corticolimbic neuroplasticity, autism-related neuroanatomical changes, as well alterations in social behaviour. Hence, the view is emerging that early life changes in serotonin levels influence the developmental course of socio-emotional brain circuits that are relevant for autism and other neurodevelopmental disorders. It is particularly exciting that the effects of embryonic and perinatal SSRI exposure and serotonin transporter gene variation on neurodevelopment seem to overlap to a large extent, at the cellular as well as the behavioural level. Yet, the precise mechanisms by which serotonin mediates neurodevelopment in the normal and ´autistic´ brain is unclear. Whereas serotonin has a placental origin during early gestation, serotonergic neurons develop during midgestation under the control of a cascade of transcription factors determining the fate of mid-hindbrain neurons that together for the Raphe nuclei. These neurons are among the earliest neurons to be generated, and because serotonin is released before any conventional synapses are formed, serotonin is suspected to influence crucial neurodevelopmental processes such as proliferation,migration and network formation. During late gestation they target their final destinations in, for instance, the cortex, where they affect the secretion of reelin. Reelin is a secreted extracellular matrix glycoprotein that helps to regulate processes of neuronal migration and positioning in the developing cortex by controlling cell–cell interactions. During the late prenatal and early postnatal phase (in rodents) serotonin further shapes the outgrowth of projecting neurons, synaptic connectivity, and the morphology of white fiber tracts. This is under the influence of transient serotonin transporter expression in (thalamo)cortical projections, sensory and prefrontal cortices and the hippocampus, as well as the local expression patterns of 5-HT1A, 5-HT1B and 5-HT3A receptors that each exert their specific roles in neuronal migration, remodeling of axons, and controlling dendritic complexity. There is also evidence that serotonin influences neural activity in locus ceroeleus neurons. Hence, serotonin appears to influence the development of both short- and long-distance connections in the brain. This Research Topic is devoted to studies pinpointing the neurodevelopmental effects of serotonin in relation to prenatal SSRI exposure, serotonin transporter gene variation, and autism/neurodevelopmental disorders, using a wide-variety of cellular and molecular neurobiological techniques like, (epi)genetics, knockout, knockdown, neuroanatomy, physiology, MRI and behaviour in rodents and humans. We especially encouraged attempts to cross-link the neurodevelopmental processes across the fields of prenatal SSRI exposure, serotonin transporter gene variation, and autism/neurodevelopmental disorders, as well as new views on the positive or beneficial effects on serotonin-mediated neurodevelopmental changes.

Plant cell wall in pathogenesis, parasitism and symbiosis

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194421 Year: Pages: 150 DOI: 10.3389/978-2-88919-442-1 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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The cell wall is a complex structure mainly composed of cellulose microfibrils embedded in a cohesive hemicellulose and pectin matrix. Cell wall structural proteins, enzymes and their inhibitors are also essential components of plant cell walls. They are involved in the cross-link of cell wall polysaccharides, wall structure, and the perception and signaling of defense-related elicitors at the cell surface. In the outer part of the epidermal cells, the polysaccharides are coated by the cuticle, consisting of hydrophobic cutin, suberin and wax layers. Lignin, a macromolecule composed of highly cross-linked phenolic molecules, is a major component of the secondary cell wall. The cell wall is the first cell structure on which interactions between plants and a wide range of other organisms, including insects, nematodes, pathogenic or symbiotic micro-organisms take place. It not only represents a barrier that limits access to the cellular contents that provide a rich nutrient source for pathogens but serves as a source of elicitors of plant defense responses released upon partial enzymatic degradation of wall polysaccharides during infection. Modification of the plant cell wall can also occur at the level of plasmodesmata during virus infection as well as during abiotic stresses. The fine structure and composition of the plant cell wall as well as the regulation of its biosynthesis can thus strongly influence resistance and susceptibility to pathogens. This Research Topic provides novel insights and detailed overviews on the dynamics of the plant cell wall in plant defence, parasitism and symbiosis and describes experimental approaches to study plant cell wall modifications occurring during interaction of plants with different organisms.

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