171 results on '"Stern DB"'
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2. Revolutionizing academic hiring: a faculty cluster hire emphasizing teamwork.
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Stern DB
- Subjects
- Humans, Cooperative Behavior, Academies and Institutes, Faculty, Personnel Selection
- Abstract
The Boyce Thompson Institute (BTI) executed a faculty cluster hiring initiative to find scientists driven by the possibilities of collaboration. Given that academic hiring rarely evaluates and rewards teamwork, BTI invented a process that would. In doing so, the Institute was able to reduce gender bias commonly found in a typical academic search., (Copyright © 2024 Elsevier Ltd. All rights reserved.)
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- 2024
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3. Transgenic expression of Rubisco accumulation factor2 and Rubisco subunits increases photosynthesis and growth in maize.
- Author
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Eshenour K, Hotto A, Michel EJS, Oh ZG, and Stern DB
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- Gene Expression Regulation, Plant, Zea mays genetics, Zea mays growth & development, Zea mays metabolism, Ribulose-Bisphosphate Carboxylase metabolism, Ribulose-Bisphosphate Carboxylase genetics, Photosynthesis, Plants, Genetically Modified genetics, Plant Proteins metabolism, Plant Proteins genetics
- Abstract
Carbon assimilation by Rubisco is often a limitation to photosynthesis and therefore plant productivity. We have previously shown that transgenic co-expression of the Rubisco large (LS) and small (SS) subunits along with an essential Rubisco accumulation factor, Raf1, leads to faster growth, increased photosynthesis, and enhanced chilling tolerance in maize (Zea mays). Maize also requires Rubisco accumulation factor2 (Raf2) for full accumulation of Rubisco. Here we have analyzed transgenic maize lines with increased expression of Raf2 or Raf2 plus LS and SS. We show that increasing Raf2 expression alone had minor effects on photosynthesis, whereas expressing Raf2 with Rubisco subunits led to increased Rubisco content, more rapid carbon assimilation, and greater plant height, most notably in plants at least 6 weeks of age. The magnitude of the effects was similar to what was observed previously for expression of Raf1 together with Rubisco subunits. Taken together, this suggests that increasing the amount of either assembly factor with Rubisco subunits can independently enhance Rubisco abundance and some aspects of plant performance. These results could also imply either synergy or a degree of functional redundancy for Raf1 and Raf2, the latter of whose precise role in Rubisco assembly is currently unknown., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
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- 2024
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4. Commentary: The Role of the Theory of Unformulated Experience in Anne Erreich's "The Innate Capacity for the Representation of Subjective Experience: The Infant's Mind Is Neither Primitive nor Prerepresentational".
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Stern DB
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- Humans, Infant, Psychoanalytic Theory
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- 2024
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5. Interpretation: Voice of the Field.
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Stern DB
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- Humans, Emotions, Psychoanalytic Interpretation, Professional-Patient Relations, Psychoanalytic Therapy, Psychoanalysis
- Abstract
To patients, the most memorable moments in psychoanalytic treatment are seldom the contents of the analyst's interpretations, but the feeling of being understood. Interpretations are most meaningful not because of what they say but because each one is evidence that the analyst, who generally becomes someone of great significance to the patient, knows the patient more than before the interpretation was made. As a result of this process of "witnessing" patients not only know and feel-they also "know and feel that they know and feel." They can feel their roles in authoring their own experience. Therapeutic action results: patients "come into possession of themselves." Interpretations are the outcome of shifts in the interpersonal field, which reveal this new freedom to think and feel. This new freedom allows the creation of the analyst's interpretations, which therefore serve as a sign of a new way of being in one another's presence that has now become possible between analyst and patient. Field shifts are jointly created, without conscious intention, and interpretations arise from these shifts. Thus, interpretations are not really created independently by the mind of the analyst, but are instead the voice of the field. A clinical vignette illustrates these ideas.
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- 2023
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6. Delivery mode impacts gut bacteriophage colonization during infancy.
- Author
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Subramanian P, Romero-Soto HN, Stern DB, Maxwell GL, Levy S, and Hourigan SK
- Abstract
Background: Cesarean section delivery is associated with altered early-life bacterial colonization and later adverse inflammatory and immune health outcomes. Although gut bacteriophages can alter gut microbiome composition and impact host immune responses, little is known about how delivery mode impacts bacteriophage colonization over time. To begin to address this we examined how delivery mode affected bacteriophage colonization over the first two years of life., Results: Shotgun metagenomic sequencing was conducted on 272 serial stool samples from 55 infants, collected at 1-2 days of life and 2, 6, 12 and 24 months. 33/55 (60%) infants were born by vaginal delivery. DNA viruses were identified, and by host inference, 94% of the viral sequences were found to be bacteriophages. Alpha diversity of the virome was increased in vaginally delivered infants compared to cesarean section delivered infants at 2 months (Shannon index, p=0.022). Beta diversity significantly differed by delivery mode at 2, 6, and 12 months when stratified by peripartum antibiotic use (Bray-Curtis dissimilarity, all p<0.05). Significant differentially abundant predicted bacteriophage hosts by delivery mode were seen at all time points. Moreover, there were differences in predicted bacteriophage functional gene abundances up to 24 months by delivery mode. Many of the functions considered to play a role in host response were increased in vaginal delivery., Conclusions: Clear differences in bacteriophage composition and function were seen by delivery mode over the first two years of life. Given that phages are known to affect host immune response, our results suggest that future investigation into how delivery mode may lead to adverse inflammatory outcomes should not only include bacterial microbial colonization but also the potential role of bacteriophages and transkingdom interactions., Competing Interests: Competing interests: The authors declare that they have no competing interests.
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- 2023
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7. Anatomical Connectivity of the Intercalated Cells of the Amygdala.
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Stern DB, Wilke A, and Root CM
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- Mice, Animals, Amygdala physiology, Neurons physiology, Transcription Factors metabolism, Extinction, Psychological physiology, Fear physiology
- Abstract
The intercalated cells of the amygdala (ITCs) are a fundamental processing structure in the amygdala that remain relatively understudied. They are phylogenetically conserved from insectivores through primates, inhibitory, and project to several of the main processing and output stations of the amygdala and basal forebrain. Through these connections, the ITCs are best known for their role in conditioned fear, where they are required for fear extinction learning and recall. Prior work on ITC connectivity is limited, and thus holistic characterization of their afferent and efferent connectivity in a genetically defined manner is incomplete. The ITCs express the FoxP2 transcription factor, affording genetic access to these neurons for viral input-output mapping. To fully characterize the anatomic connectivity of the ITCs, we used cre-dependent viral strategies in FoxP2-cre mice to reveal the projections of the main (mITC), caudal (cITC), and lateral (lITC) clusters along with their presynaptic sources of innervation. Broadly, the results confirm many known pathways, reveal previously unknown ones, and demonstrate important novel insights about each nucleus's unique connectivity profile and relative distributions. We show that the ITCs receive information from a wide range of cortical, subcortical, basal, amygdalar, hippocampal, and thalamic structures, and project broadly to areas of the basal forebrain, hypothalamus, and entire extent of the amygdala. The results provide a comprehensive map of their connectivity and suggest that the ITCs could potentially influence a broad range of behaviors by integrating information from a wide array of sources throughout the brain., Competing Interests: The authors declare no competing financial interests., (Copyright © 2023 Stern et al.)
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- 2023
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8. Amphibian myelopoiesis.
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Yaparla A, Stern DB, Hossainey MRH, Crandall KA, and Grayfer L
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- Animals, Macrophages, Cell Differentiation, Hematopoiesis, Xenopus laevis, Myelopoiesis, Amphibians
- Abstract
Macrophage-lineage cells are indispensable to immunity and physiology of all vertebrates. Amongst these, amphibians represent a key stage in vertebrate evolution and are facing decimating population declines and extinctions, in large part due to emerging infectious agents. While recent studies indicate that macrophages and related innate immune cells are critically involved during these infections, much remains unknown regarding the ontogeny and functional differentiation of these cell types in amphibians. Accordingly, in this review we coalesce what has been established to date about amphibian blood cell development (hematopoiesis), the development of key amphibian innate immune cells (myelopoiesis) and the differentiation of amphibian macrophage subsets (monopoiesis). We explore the current understanding of designated sites of larval and adult hematopoiesis across distinct amphibian species and consider what mechanisms may lend to these species-specific adaptations. We discern the identified molecular mechanisms governing the functional differentiation of disparate amphibian (chiefly Xenopus laevis) macrophage subsets and describe what is known about the roles of these subsets during amphibian infections with intracellular pathogens. Macrophage lineage cells are at the heart of so many vertebrate physiological processes. Thus, garnering greater understanding of the mechanisms responsible for the ontogeny and functionality of these cells in amphibians will lend to a more comprehensive view of vertebrate evolution., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
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- 2023
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9. Distance And Relation: Emerging From Embeddedness In The Other.
- Author
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Stern DB
- Subjects
- Humans, Professional-Patient Relations, Psychoanalytic Therapy, Psychoanalysis
- Abstract
Inspired by an essay by Martin Buber (1950), and then by the work of Ernest Schachtel (1959) on the idea of "embeddedness" and emergence from it, this essay is an account of the role of "distance" or "separateness" in clinical psychoanalytic work. We tend to assume that the capacity to appreciate otherness is always already present. We often lose track of the necessity to "set the other at a distance" (Buber), the prerequisite for emergence from embeddedness in the other. The entire process-i.e., setting the other at a distance and then emerging from embeddedness in the other-must take place over and over again in any treatment, and in both directions: patients must disembed from analysts, but it is just as necessary for analysts to disembed from patients. It is the emergence from embeddedness that allows the analyst's appreciation of the patient's otherness. Embeddedness in the other is discussed as mutual enactment. This use of these phenomena in treatment is articulated in the theory of witnessing presented elsewhere in recent years (Stern 2009, 2012, 2022b, in press). A detailed clinical illustration is presented.
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- 2023
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10. Commentary on Markman's Vignette.
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Stern DB
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- 2023
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11. A Phylogenetic Framework to Simulate Synthetic Interspecies RNA-Seq Data.
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Bastide P, Soneson C, Stern DB, Lespinet O, and Gallopin M
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- RNA-Seq, Phylogeny, Sequence Analysis, RNA methods, Software, Gene Expression Profiling methods
- Abstract
Interspecies RNA-Seq datasets are increasingly common, and have the potential to answer new questions about the evolution of gene expression. Single-species differential expression analysis is now a well-studied problem that benefits from sound statistical methods. Extensive reviews on biological or synthetic datasets have provided the community with a clear picture on the relative performances of the available methods in various settings. However, synthetic dataset simulation tools are still missing in the interspecies gene expression context. In this work, we develop and implement a new simulation framework. This tool builds on both the RNA-Seq and the phylogenetic comparative methods literatures to generate realistic count datasets, while taking into account the phylogenetic relationships between the samples. We illustrate the usefulness of this new framework through a targeted simulation study, that reproduces the features of a recently published dataset, containing gene expression data in adult eye tissue across blind and sighted freshwater crayfish species. Using our simulated datasets, we perform a fair comparison of several approaches used for differential expression analysis. This benchmark reveals some of the strengths and weaknesses of both the classical and phylogenetic approaches for interspecies differential expression analysis, and allows for a reanalysis of the crayfish dataset. The tool has been integrated in the R package compcodeR, freely available on Bioconductor., (© The Author(s) 2022. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)
- Published
- 2023
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12. Gut microbiota changes are detected in asymptomatic very young children with SARS-CoV-2 infection.
- Author
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Nashed L, Mani J, Hazrati S, Stern DB, Subramanian P, Mattei L, Bittinger K, Hu W, Levy S, Maxwell GL, and Hourigan SK
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- Child, Child, Preschool, Gastrointestinal Tract, Humans, SARS-CoV-2, COVID-19, Gastrointestinal Microbiome
- Abstract
Competing Interests: Competing interests: None declared.
- Published
- 2022
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13. Removing systemic barriers to equity, diversity, and inclusion: Report of the 2019 Plant Science Research Network workshop "Inclusivity in the Plant Sciences".
- Author
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Henkhaus NA, Busch W, Chen A, Colón-Carmona A, Cothran M, Diaz N, Dundore-Arias JP, Gonzales M, Hadziabdic D, Hayes RA, MacIntosh GC, Na A, Nyamasoka-Magonziwa B, Pater D, Peritore-Galve FC, Phelps-Durr T, Rouhier K, Sickler DB, Starnes JH, Tyler QR, Valdez-Ward E, Vega-Sánchez ME, Walcott RR, Ward JK, Wyatt SE, Zapata F, Zemenick AT, and Stern DB
- Abstract
A future in which scientific discoveries are valued and trusted by the general public cannot be achieved without greater inclusion and participation of diverse communities. To envision a path towards this future, in January 2019 a diverse group of researchers, educators, students, and administrators gathered to hear and share personal perspectives on equity, diversity, and inclusion (EDI) in the plant sciences. From these broad perspectives, the group developed strategies and identified tactics to facilitate and support EDI within and beyond the plant science community. The workshop leveraged scenario planning and the richness of its participants to develop recommendations aimed at promoting systemic change at the institutional level through the actions of scientific societies, universities, and individuals and through new funding models to support research and training. While these initiatives were formulated specifically for the plant science community, they can also serve as a model to advance EDI in other disciplines. The proposed actions are thematically broad, integrating into discovery, applied and translational science, requiring and embracing multidisciplinarity, and giving voice to previously unheard perspectives. We offer a vision of barrier-free access to participation in science, and a plant science community that reflects the diversity of our rapidly changing nation, and supports and invests in the training and well-being of all its members. The relevance and robustness of our recommendations has been tested by dramatic and global events since the workshop. The time to act upon them is now., Competing Interests: The Authors did not report any conflict of interest., (© 2022 The Authors. Plant Direct published by American Society of Plant Biologists and the Society for Experimental Biology and John Wiley & Sons Ltd.)
- Published
- 2022
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14. Genome-wide signatures of synergistic epistasis during parallel adaptation in a Baltic Sea copepod.
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Stern DB, Anderson NW, Diaz JA, and Lee CE
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- Adaptation, Physiological genetics, Alleles, Animals, Epistasis, Genetic, Selection, Genetic, Copepoda genetics
- Abstract
The role of epistasis in driving adaptation has remained an unresolved problem dating back to the Evolutionary Synthesis. In particular, whether epistatic interactions among genes could promote parallel evolution remains unexplored. To address this problem, we employ an Evolve and Resequence (E&R) experiment, using the copepod Eurytemora affinis, to elucidate the evolutionary genomic response to rapid salinity decline. Rapid declines in coastal salinity at high latitudes are a predicted consequence of global climate change. Based on time-resolved pooled whole-genome sequencing, we uncover a remarkably parallel, polygenic response across ten replicate selection lines, with 79.4% of selected alleles shared between lines by the tenth generation of natural selection. Using extensive computer simulations of our experiment conditions, we find that this polygenic parallelism is consistent with positive synergistic epistasis among alleles, far more so than other mechanisms tested. Our study provides experimental and theoretical support for a novel mechanism promoting repeatable polygenic adaptation, a phenomenon that may be common for selection on complex physiological traits., (© 2022. The Author(s).)
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- 2022
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15. On Coming Into Possession of Oneself: Witnessing and the Formulation of Experience.
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Stern DB
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- Humans, Recognition, Psychology, Trust, Emotions, Mental Processes
- Abstract
In this paper I use clinical theory and illustration to explore details of the formulation of experience, which depends upon the metamorphosis of experience from not-me to feels-like-me. I take the position that the movement from not-me to feels-like-me, with the accompanying possibilities for formulating new meaning that open at such moments, happens when we not only know or feel something, but also, and simultaneously, sense ourselves in the midst of this process-that is, when we know and feel that it is we who are doing the knowing and feeling. When these two events co-occur, which depends upon the process of witnessing and the breach of dissociation, we come into possession of ourselves. Witnessing of one person by another is a process of recognition, but it is also a kind of affirmation performed by "someone who is trusted and justifies the trust and meets the dependence" (Winnicott 1971, p. 60).
- Published
- 2022
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16. The genus Creaserinus Hobbs, 1973 (Decapoda: Cambaridae) in Texas.
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Johnson DP, Stern DB, and Crandall KA
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- Animal Distribution, Animals, Female, Male, Texas, Astacoidea, Ecosystem
- Abstract
Presented is an account of the crayfish genus Creaserinus Hobbs, 1973 for Texas, based on materials gathered during a 13-year survey of the state. Home to Texas are six members of the genus, including C. hedgpethi (Hobbs, 1948) stat. rev., n. comb., which is resurrected from the synonymy of C. fodiens; and five species new to science described herein, including C. brevistylus n. sp., C. clausus n. sp., C. crenastylus n. sp., C. limulus n. sp., and C. trinensis n. sp. Collections of these species except for C. trinensis n. sp. were previously known and studied but ascribed to C. fodiens (Cottle, 1863), which is removed from the fauna of the state. Support for the taxonomic acts comes from genetics, morphology, distribution, life history, habitat, and syntopy. Accounts are provided for each species and include illustrations and information on distribution, color pattern, relationships, life history, ecology, size, variations, and crayfish associates. A key to the species in the state based on form I males is provided. Creaserinus limulus n. sp. is extraordinary in that a majority of its populations sampled have been composed mostly or entirely of females. Additions to the faunas of Texass neighboring states include C. clausus n. sp. (Louisiana), C. crenastylus n. sp. (Louisiana), and C. limulus n. sp. (Arkansas and Oklahoma).
- Published
- 2021
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17. Rubisco production in maize mesophyll cells through ectopic expression of subunits and chaperones.
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Hotto AM, Salesse-Smith C, Lin M, Busch FA, Simpson I, and Stern DB
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- Chloroplasts metabolism, Ectopic Gene Expression, Mesophyll Cells metabolism, Photosynthesis, Ribulose-Bisphosphate Carboxylase genetics, Ribulose-Bisphosphate Carboxylase metabolism, Zea mays genetics, Zea mays metabolism
- Abstract
C4 plants, such as maize, strictly compartmentalize Rubisco to bundle sheath chloroplasts. The molecular basis for the restriction of Rubisco from the more abundant mesophyll chloroplasts is not fully understood. Mesophyll chloroplasts transcribe the Rubisco large subunit gene and, when normally quiescent transcription of the nuclear Rubisco small subunit gene family is overcome by ectopic expression, mesophyll chloroplasts still do not accumulate measurable Rubisco. Here we show that a combination of five ubiquitin promoter-driven nuclear transgenes expressed in maize leads to mesophyll accumulation of assembled Rubisco. These encode the Rubisco large and small subunits, Rubisco assembly factors 1 and 2, and the assembly factor Bundle sheath defective 2. In these plants, Rubisco large subunit accumulates in mesophyll cells, and appears to be assembled into a holoenzyme capable of binding the substrate analog CABP (carboxyarabinitol bisphosphate). Isotope discrimination assays suggest, however, that mesophyll Rubisco is not participating in carbon assimilation in these plants, most probably due to a lack of the substrate ribulose 1,5-bisphosphate and/or Rubisco activase. Overall, this work defines a minimal set of Rubisco assembly factors in planta and may help lead to methods of regulating the C4 pathway., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2021
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18. Philip M. Bromberg (1931-2020). Trauma, dissociation, and the multiple self.
- Author
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Stern DB
- Subjects
- Humans, Psychoanalysis
- Published
- 2021
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19. CFM1, a member of the CRM-domain protein family, functions in chloroplast group II intron splicing in Setaria viridis.
- Author
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Feiz L, Asakura Y, Mao L, Strickler SR, Fei Z, Rojas M, Barkan A, and Stern DB
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- Chloroplast Proteins genetics, Introns, Mutation, Plant Proteins metabolism, Protein Biosynthesis, Protein Domains, RNA, Transfer, Chloroplasts genetics, Plant Proteins genetics, RNA Splicing, Setaria Plant genetics, Zea mays genetics
- Abstract
The chloroplast RNA splicing and ribosome maturation (CRM) domain is a RNA-binding domain found in a plant-specific protein family whose characterized members play essential roles in splicing group I and group II introns in mitochondria and chloroplasts. Together, these proteins are required for splicing of the majority of the approximately 20 chloroplast introns in land plants. Here, we provide evidence from Setaria viridis and maize that an uncharacterized member of this family, CRM Family Member1 (CFM1), promotes the splicing of most of the introns that had not previously been shown to require a CRM domain protein. A Setaria mutant expressing mutated CFM1 was strongly disrupted in the splicing of three chloroplast tRNAs: trnI, trnV and trnA. Analyses by RNA gel blot and polysome association suggest that the tRNA deficiencies lead to compromised chloroplast protein synthesis and the observed whole-plant chlorotic phenotypes. Co-immunoprecipitation data demonstrate that the maize CFM1 ortholog is bound to introns whose splicing is disrupted in the cfm1 mutant. With these results, CRM domain proteins have been shown to promote the splicing of all but two of the introns found in angiosperm chloroplast genomes., (© 2020 Society for Experimental Biology and John Wiley & Sons Ltd.)
- Published
- 2021
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20. Setaria viridis chlorotic and seedling-lethal mutants define critical functions for chloroplast gene expression.
- Author
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Feiz L, Strickler SR, van Eck J, Mao L, Movahed N, Taylor C, Gourabathini P, Fei Z, and Stern DB
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- Arabidopsis genetics, Arabidopsis physiology, Chloroplasts metabolism, Isoenzymes, Mutation, Phenotype, Photosynthesis genetics, Plant Proteins genetics, Polyribonucleotide Nucleotidyltransferase genetics, Polyribonucleotide Nucleotidyltransferase metabolism, RNA Editing, RNA, Chloroplast genetics, Ribosomal Proteins genetics, Ribosomal Proteins metabolism, Seedlings genetics, Seedlings physiology, Sequence Analysis, RNA, Setaria Plant physiology, Chloroplasts genetics, Gene Expression Regulation, Plant genetics, Plant Proteins metabolism, Setaria Plant genetics
- Abstract
Deep insights into chloroplast biogenesis have been obtained by mutant analysis; however, in C
4 plants a relevant mutant collection has only been developed and exploited for maize. Here, we report the initial characterization of an ethyl methyl sulfonate-induced mutant population for the C4 model Setaria viridis. Approximately 1000 M2 families were screened for the segregation of pale-green seedlings in the M3 generation, and a subset of these was identified to be deficient in post-transcriptional steps of chloroplast gene expression. Causative mutations were identified for three lines using deep sequencing-based bulked segregant analysis, and in one case confirmed by transgenic complementation. Using chloroplast RNA-sequencing and other molecular assays, we describe phenotypes of mutants deficient in PSRP7, a plastid-specific ribosomal protein, OTP86, an RNA editing factor, and cpPNP, the chloroplast isozyme of polynucleotide phosphorylase. The psrp mutant is globally defective in chloroplast translation, and has varying deficiencies in the accumulation of chloroplast-encoded proteins. The otp86 mutant, like its Arabidopsis counterpart, is specifically defective in editing of the rps14 mRNA; however, the conditional pale-green mutant phenotype contrasts with the normal growth of the Arabidopsis mutant. The pnp mutant exhibited multiple defects in 3' end maturation as well as other qualitative changes in the chloroplast RNA population. Overall, our collection opens the door to global analysis of photosynthesis and early seedling development in an emerging C4 model., (© 2020 Society for Experimental Biology and John Wiley & Sons Ltd.)- Published
- 2020
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21. Dissociative Multiplicity and Unformulated Experience: Commentary on Diamond.
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Stern DB
- Subjects
- Dissociative Disorders, Humans, Psychotherapy, Repression, Psychology, Psychoanalysis
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- 2020
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22. Hemiptera phylogenomic resources: Tree-based orthology prediction and conserved exon identification.
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Owen CL, Stern DB, Hilton SK, and Crandall KA
- Subjects
- Animals, Genome, Genomics, Exons, Hemiptera classification, Hemiptera genetics, Phylogeny
- Abstract
High-throughput sequencing of transcriptomes and targeted genomic regions are advancing our knowledge of The Tree of Life. Building phylogenies with regions of the genome requires 1-to-1 orthologue resources of genes and noncoding loci. One organismal group that has received little attention in this area is the Hemiptera, the fifth largest insect order represented by ~103,590 named species. Here, we present a set of 3,872 Hemiptera 1-to-1 orthogroups based on tree-based orthology inference of eight Hemiptera species with publicly available genome sequences. We also estimate a set of 406 orthologous exons with similar mRNA splice sites that can be used for Sanger sequencing and develop enrichment probes for targeted genome sequencing for phylogenomic inference. We show this novel set of orthologues is informative at the protein, coding sequence and exon molecular levels and provides robust branch support in both gene tree-species tree methods and concatenated sequence phylogenies. In addition, we demonstrate the utility of these loci to resolve relationships in whiteflies, Bemisia tabaci, a large species complex with few phylogenomic resources. Last, we compare our Hemiptera phylogeny with previously published phylogenies and other orthologue databases, while providing suggestions on further improvement to this phylogenomic resource., (© 2020 John Wiley & Sons Ltd.)
- Published
- 2020
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23. Evolutionary origins of genomic adaptations in an invasive copepod.
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Stern DB and Lee CE
- Subjects
- Acclimatization, Adaptation, Physiological genetics, Animals, Genome, Genomics, Copepoda genetics
- Abstract
The ability of populations to expand their geographical ranges, whether as invaders, agricultural strains or climate migrants, is currently one of the most serious global problems. However, fundamental mechanisms remain poorly understood regarding factors that enable certain populations, such as biological invaders, to rapidly transition to novel habitats. According to one hypothesis, environmental fluctuations in the native range could promote successful invasions by imposing balancing selection on key traits and maintaining the genetic variation that enables rapid adaptation in novel habitats. Here we test the genomic predictions of this hypothesis by performing whole-genome sequencing of multiple independent invasive freshwater and native saline populations of the copepod Eurytemora affinis complex. We found that invasive populations have repeatedly responded to selection through the parallel use of the same single-nucleotide polymorphisms and genomic loci, to a much greater degree than expected. These same loci were enriched for signatures of long-term balancing selection in the native ranges, with 15-47% of loci exhibiting significant signatures of balancing selection. The strong association between parallel evolution in the invaded range and balancing selection in the native range supports the hypothesis that fluctuating habitats can promote invasive success and that balancing selection might serve as a widespread and important mechanism that enables rapid adaptation in nature.
- Published
- 2020
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24. Increased Rubisco content in maize mitigates chilling stress and speeds recovery.
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Salesse-Smith CE, Sharwood RE, Busch FA, and Stern DB
- Subjects
- Cold Temperature, Photosynthesis, Poaceae metabolism, Ribulose-Bisphosphate Carboxylase metabolism, Zea mays genetics, Zea mays metabolism
- Abstract
Many C
4 plants, including maize, perform poorly under chilling conditions. This phenomenon has been linked in part to decreased Rubisco abundance at lower temperatures. An exception to this is chilling-tolerant Miscanthus, which is able to maintain Rubisco protein content under such conditions. The goal of this study was to investigate whether increasing Rubisco content in maize could improve performance during or following chilling stress. Here, we demonstrate that transgenic lines overexpressing Rubisco large and small subunits and the Rubisco assembly factor RAF1 (RAF1-LSSS), which have increased Rubisco content and growth under control conditions, maintain increased Rubisco content and growth during chilling stress. RAF1-LSSS plants exhibited 12% higher CO2 assimilation relative to nontransgenic controls under control growth conditions, and a 17% differential after 2 weeks of chilling stress, although assimilation rates of all genotypes were ~50% lower in chilling conditions. Chlorophyll fluorescence measurements showed RAF1-LSSS and WT plants had similar rates of photochemical quenching during chilling, suggesting Rubisco may not be the primary limiting factor that leads to poor performance in maize under chilling conditions. In contrast, RAF1-LSSS had improved photochemical quenching before and after chilling stress, suggesting that increased Rubisco may help plants recover faster from chilling conditions. Relatively increased leaf area, dry weight and plant height observed before chilling in RAF1-LSSS were also maintained during chilling. Together, these results demonstrate that an increase in Rubisco content allows maize plants to better cope with chilling stress and also improves their subsequent recovery, yet additional modifications are required to engineer chilling tolerance in maize., (© 2019 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)- Published
- 2020
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25. Consumption of Diet Soda Sweetened with Sucralose and Acesulfame-Potassium Alters Inflammatory Transcriptome Pathways in Females with Overweight and Obesity.
- Author
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Sylvetsky AC, Sen S, Merkel P, Dore F, Stern DB, Henry CJ, Cai H, Walter PJ, Crandall KA, Rother KI, and Hubal MJ
- Subjects
- Adipose Tissue physiology, Female, Gene Expression Regulation drug effects, Humans, Obesity metabolism, Obesity physiopathology, Panniculitis chemically induced, Panniculitis immunology, Panniculitis metabolism, Sucrose adverse effects, Sweetening Agents adverse effects, Young Adult, Adipose Tissue drug effects, Artificially Sweetened Beverages adverse effects, Sucrose analogs & derivatives, Thiazines adverse effects
- Abstract
Scope: Low-calorie sweetener (LCS) consumption is associated with metabolic disease in observational studies. However, physiologic mechanisms underlying LCS-induced metabolic impairments in humans are unclear. This study is aimed at identifying molecular pathways in adipose impacted by LCSs., Methods and Results: Seven females with overweight or obesity, who did not report LCS use, consumed 12 ounces of diet soda containing sucralose and acesulfame-potassium (Ace-K) three times daily for 8 weeks. A subcutaneous adipose biopsy from the left abdomen and a fasting blood sample were collected at baseline and post-intervention. Global gene expression were assessed using RNA-sequencing followed by functional pathway analysis. No differences in circulating metabolic or inflammatory biomarkers were observed. However, ANOVA detected 828 differentially expressed annotated genes after diet soda consumption (p < 0.05), including transcripts for inflammatory cytokines. Fifty-eight of 140 canonical pathways represented in pathway analyses regulated inflammation, and several key upstream regulators of inflammation (e.g., TNF-alpha) were also represented., Conclusion: Consumption of diet soda with sucralose and Ace-K alters inflammatory transcriptomic pathways (e.g., NF-κB signaling) in subcutaneous adipose tissue but does not significantly alter circulating biomarkers. Findings highlight the need to examine molecular and metabolic effects of LCS exposure in a larger randomized control trial for a longer duration., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2020
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26. Plant Ribonuclease J: An Essential Player in Maintaining Chloroplast RNA Quality Control for Gene Expression.
- Author
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Hotto AM, Stern DB, and Schuster G
- Abstract
RNA quality control is an indispensable but poorly understood process that enables organisms to distinguish functional RNAs from nonfunctional or inhibitory ones. In chloroplasts, whose gene expression activities are required for photosynthesis, retrograde signaling, and plant development, RNA quality control is of paramount importance, as transcription is relatively unregulated. The functional RNA population is distilled from this initial transcriptome by a combination of RNA-binding proteins and ribonucleases. One of the key enzymes is RNase J, a 5'→3' exoribonuclease and an endoribonuclease that has been shown to trim 5' RNA termini and eliminate deleterious antisense RNA. In the absence of RNase J, embryo development cannot be completed. Land plant RNase J contains a highly conserved C-terminal domain that is found in GT-1 DNA-binding transcription factors and is not present in its bacterial, archaeal, and algal counterparts. The GT-1 domain may confer specificity through DNA and/or RNA binding and/or protein-protein interactions and thus be an element in the mechanisms that identify target transcripts among diverse RNA populations. Further understanding of chloroplast RNA quality control relies on discovering how RNase J is regulated and how its specificity is imparted., Competing Interests: The authors declare no conflict of interest.
- Published
- 2020
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27. Systematic sequencing of chloroplast transcript termini from Arabidopsis thaliana reveals >200 transcription initiation sites and the extensive imprints of RNA-binding proteins and secondary structures.
- Author
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Castandet B, Germain A, Hotto AM, and Stern DB
- Subjects
- Arabidopsis metabolism, Arabidopsis Proteins chemistry, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, DNA, Plant analysis, DNA, Plant genetics, High-Throughput Nucleotide Sequencing, Plants, Genetically Modified, Protein Structure, Secondary, Sequence Analysis, DNA, Transcriptome, Arabidopsis genetics, Chloroplasts genetics, Genomic Imprinting physiology, RNA-Binding Proteins chemistry, RNA-Binding Proteins genetics, RNA-Binding Proteins metabolism, Transcription Initiation Site
- Abstract
Chloroplast transcription requires numerous quality control steps to generate the complex but selective mixture of accumulating RNAs. To gain insight into how this RNA diversity is achieved and regulated, we systematically mapped transcript ends by developing a protocol called Terminome-seq. Using Arabidopsis thaliana as a model, we catalogued >215 primary 5' ends corresponding to transcription start sites (TSS), as well as 1628 processed 5' ends and 1299 3' ends. While most termini were found in intergenic regions, numerous abundant termini were also found within coding regions and introns, including several major TSS at unexpected locations. A consistent feature was the clustering of both 5' and 3' ends, contrasting with the prevailing description of discrete 5' termini, suggesting an imprecision of the transcription and/or RNA processing machinery. Numerous termini correlated with the extremities of small RNA footprints or predicted stem-loop structures, in agreement with the model of passive RNA protection. Terminome-seq was also implemented for pnp1-1, a mutant lacking the processing enzyme polynucleotide phosphorylase. Nearly 2000 termini were altered in pnp1-1, revealing a dominant role in shaping the transcriptome. In summary, Terminome-seq permits precise delineation of the roles and regulation of the many factors involved in organellar transcriptome quality control., (© The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2019
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28. A Magic World.
- Author
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Stern DB
- Published
- 2019
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29. Reinventing postgraduate training in the plant sciences: T-training defined through modularity, customization, and distributed mentorship.
- Author
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Henkhaus NA, Taylor CB, Greenlee VR, Sickler DB, and Stern DB
- Abstract
The Plant Science Research Network (PSRN) comprises scientific societies and organizations with a mission to build and communicate a consensus vision of the future of plant science research, education, and training. This report enumerates a set of far-reaching recommendations for postgraduate training that emerged from workshops held in October 2016 and September 2017. These recommendations broaden and deepen the T-training concept presented in the Decadal Vision for Plant Science, which emphasizes experiential learning beyond the traditional disciplinary focus. Both workshops used the scenarios developed in Imagining Science in 2035 as a mechanism to encourage out-of-the-box thinking, an approach that led to the innovative recommendations and solutions described here. At the heart of our recommendations is the empowerment of trainees, who should be enabled to customize and take ownership of their training experiences. This fundamental concept is embodied in five principles: (a) Trainees should be provided guidance and resources needed to define and pursue career objectives within and beyond academia, conferring to them greater independence and responsibility in shaping their own future. (b) Learning should be flexible, adaptable, and distributed. Training should combine traditional and modular coursework to encompass both technical and professional skills. Guidance from diverse mentoring teams will support and tailor training toward diverse, personalized career paths. (c) Scientific research experiences should be broad and question-driven, whether motivated by basic discovery or seeking solutions to societal challenges. Trainees should continue to gain mastery of one or a few core scientific disciplines and their key tools and approaches. (d) Trainees should be skilled in science communication and incentivized to engage with and learn from the broader public community, helping to maintain an active dialogue among public, private, and academic sectors. (e) Training programs should foster and facilitate the inclusion of individuals with a diverse range of life experiences and should prioritize trainee well-being. The report recommendations call for a profound cultural shift, one that embraces and extends educational delivery trends toward self-learning and distance learning, considers trainee well-being as an essential requirement for success, and acknowledges the importance of effective two-way communication with the public. This shift is intended to broaden participation in the plant science workforce, both in terms of diversity and numbers, while maintaining excellence in core scientific training. Cultural change takes time, but among academic institutions the need for significant change and innovation in postgraduate training is increasingly pressing. As such, the immediate intent is for these recommendations to catalyze pilot programs and also build on emergent prototypes that exist globally while creating momentum for larger scale changes over longer time periods.
- Published
- 2018
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30. Overexpression of Rubisco subunits with RAF1 increases Rubisco content in maize.
- Author
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Salesse-Smith CE, Sharwood RE, Busch FA, Kromdijk J, Bardal V, and Stern DB
- Subjects
- Chloroplasts metabolism, Immunoblotting, Molecular Chaperones metabolism, Photosynthesis, Plants, Genetically Modified, Ribulose-Bisphosphate Carboxylase analysis, Zea mays chemistry, Plant Proteins metabolism, Ribulose-Bisphosphate Carboxylase metabolism, Zea mays metabolism
- Abstract
Rubisco catalyses a rate-limiting step in photosynthesis and has long been a target for improvement due to its slow turnover rate. An alternative to modifying catalytic properties of Rubisco is to increase its abundance within C
4 plant chloroplasts, which might increase activity and confer a higher carbon assimilation rate. Here, we overexpress the Rubisco large (LS) and small (SS) subunits with the Rubisco assembly chaperone RUBISCO ASSEMBLY FACTOR 1 (RAF1). While overexpression of LS and/or SS had no discernable impact on Rubisco content, addition of RAF1 overexpression resulted in a >30% increase in Rubisco content. Gas exchange showed a 15% increase in CO2 assimilation (ASAT ) in UBI-LSSS-RAF1 transgenic plants, which correlated with increased fresh weight and in vitro Vcmax calculations. The divergence of Rubisco content and assimilation could be accounted for by the Rubisco activation state, which decreased up to 23%, suggesting that Rubisco activase may be limiting Vcmax , and impinging on the realization of photosynthetic potential from increased Rubisco content.- Published
- 2018
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31. Phototransduction Gene Expression and Evolution in Cave and Surface Crayfishes.
- Author
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Stern DB and Crandall KA
- Subjects
- Animals, Caves, Light, Selection, Genetic, Species Specificity, Transcriptome physiology, Astacoidea physiology, Darkness, Evolution, Molecular, Gene Expression physiology, Light Signal Transduction genetics, Photoreceptor Cells, Invertebrate metabolism
- Abstract
In the absence of light in caves, animals have repeatedly evolved reduced eyes and visual systems. Whether the underlying genetic components remain intact in blind species remains unanswered across taxa. The freshwater crayfish have evolved to live in caves multiple times throughout their history; therefore, this system provides an opportunity to probe the genetic patterns and processes underlying repeated vision loss. Using transcriptomic data from the eyes of 14 species of cave and surface crayfishes, we identify the expression of 17 genes putatively related to visual phototransduction. We find a similarly complete repertoire of phototransduction gene families expressed in cave and surface species, but that the expression levels of those transcripts are consistently lower in cave species. We find statistical support for episodic positive selection, increased and decreased selection strength in caves, depending on the gene family. Analyses of gene expression evolution suggest convergent and possibly adaptive downregulation of these genes across eye-reduction events. Our results reveal a combination of evolutionary processes acting on the sequences and gene expression levels of vision-related genes underlying the loss of vision in caves.
- Published
- 2018
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32. The Evolution of Gene Expression Underlying Vision Loss in Cave Animals.
- Author
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Stern DB and Crandall KA
- Subjects
- Animals, Astacoidea metabolism, Multigene Family, Transcriptome, Astacoidea genetics, Eye metabolism, Genetic Drift, Selection, Genetic, Vision, Ocular genetics
- Abstract
Dissecting the evolutionary genetic processes underlying eye reduction and vision loss in obligate cave-dwelling organisms has been a long-standing challenge in evolutionary biology. Independent vision loss events in related subterranean organisms can provide critical insight into these processes as well as into the nature of convergent loss of complex traits. Advances in evolutionary developmental biology have illuminated the significant role of heritable gene expression variation in the evolution of new forms. Here, we analyze gene expression variation in adult eye tissue across the freshwater crayfish, representing four independent vision-loss events in caves. Species and individual expression patterns cluster by eye function rather than phylogeny, suggesting convergence in transcriptome evolution in independently blind animals. However, this clustering is not greater than what is observed in surface species with conserved eye function after accounting for phylogenetic expectations. Modeling expression evolution suggests that there is a common increase in evolutionary rates in the blind lineages, consistent with a relaxation of selective constraint maintaining optimal expression levels. This is evidence for a repeated loss of expression constraint in the transcriptomes of blind animals and that convergence occurs via a similar trajectory through genetic drift.
- Published
- 2018
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33. How Does History Become Accessible? Reconstruction as an Emergent Product of the Interpersonal Field.
- Author
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Stern DB
- Subjects
- Humans, Interpersonal Relations
- Published
- 2018
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34. A Guide to the Chloroplast Transcriptome Analysis Using RNA-Seq.
- Author
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Michel EJS, Hotto AM, Strickler SR, Stern DB, and Castandet B
- Subjects
- Computational Biology methods, Databases, Genetic, Genome, Chloroplast, Genomics methods, Software, Chloroplasts genetics, Gene Expression Profiling methods, High-Throughput Nucleotide Sequencing, RNA, Chloroplast, Transcriptome
- Abstract
Since its first use in plants in 2007, high-throughput RNA sequencing (RNA-Seq) has generated a vast amount of data for both model and nonmodel species. Organellar transcriptomes, however, are virtually always overlooked at the data analysis step. We therefore developed ChloroSeq, a bioinformatic pipeline aimed at facilitating the systematic analysis of chloroplast RNA metabolism, and we provide here a step-by-step user's manual. Following the alignment of quality-controlled data to the genome of interest, ChloroSeq measures genome expression level along with splicing and RNA editing efficiencies. When used in combination with the Tuxedo suite (TopHat and Cufflinks), ChloroSeq allows the simultaneous analysis of organellar and nuclear transcriptomes, opening the way to a better understanding of nucleus-organelle cross talk. We also describe the use of R commands to produce publication-quality figures based on ChloroSeq outputs. The effectiveness of the pipeline is illustrated through analysis of an RNA-Seq dataset covering the transition from growth to maturation to senescence of Arabidopsis thaliana leaves.
- Published
- 2018
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35. Phylogenetic evidence from freshwater crayfishes that cave adaptation is not an evolutionary dead-end.
- Author
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Stern DB, Breinholt J, Pedraza-Lara C, López-Mejía M, Owen CL, Bracken-Grissom H, Fetzner JW Jr, and Crandall KA
- Subjects
- Animals, Astacoidea classification, Caves, Adaptation, Physiological, Astacoidea genetics, Evolution, Molecular, Phylogeny
- Abstract
Caves are perceived as isolated, extreme habitats with a uniquely specialized biota, which long ago led to the idea that caves are "evolutionary dead-ends." This implies that cave-adapted taxa may be doomed for extinction before they can diversify or transition to a more stable state. However, this hypothesis has not been explicitly tested in a phylogenetic framework with multiple independently evolved cave-dwelling groups. Here, we use the freshwater crayfish, a group with dozens of cave-dwelling species in multiple lineages, as a system to test this hypothesis. We consider historical patterns of lineage diversification and habitat transition as well as current patterns of geographic range size. We find that while cave-dwelling lineages have small relative range sizes and rarely transition back to the surface, they exhibit remarkably similar diversification patterns to those of other habitat types and appear to be able to maintain a diversity of lineages through time. This suggests that cave adaptation is not a "dead-end" for freshwater crayfish, which has positive implications for our understanding of biodiversity and conservation in cave habitats., (© 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.)
- Published
- 2017
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36. High-throughput droplet microfluidics screening platform for selecting fast-growing and high lipid-producing microalgae from a mutant library.
- Author
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Kim HS, Hsu SC, Han SI, Thapa HR, Guzman AR, Browne DR, Tatli M, Devarenne TP, Stern DB, and Han A
- Abstract
Biofuels derived from microalgal lipids have demonstrated a promising potential as future renewable bioenergy. However, the production costs for microalgae-based biofuels are not economically competitive, and one strategy to overcome this limitation is to develop better-performing microalgal strains that have faster growth and higher lipid content through genetic screening and metabolic engineering. In this work, we present a high-throughput droplet microfluidics-based screening platform capable of analyzing growth and lipid content in populations derived from single cells of a randomly mutated microalgal library to identify and sort variants that exhibit the desired traits such as higher growth rate and increased lipid content. By encapsulating single cells into water-in-oil emulsion droplets, each variant was separately cultured inside an individual droplet that functioned as an independent bioreactor. In conjunction with an on-chip fluorescent lipid staining process within droplets, microalgal growth and lipid content were characterized by measuring chlorophyll and BODIPY fluorescence intensities through an integrated optical detection system in a flow-through manner. Droplets containing cells with higher growth and lipid content were selectively retrieved and further analyzed off-chip. The growth and lipid content screening capabilities of the developed platform were successfully demonstrated by first carrying out proof-of-concept screening using known Chlamydomonas reinhardtii mutants. The platform was then utilized to screen an ethyl methanesulfonate (EMS)-mutated C. reinhardtii population, where eight potential mutants showing faster growth and higher lipid content were selected from 200,000 examined samples, demonstrating the capability of the platform as a high-throughput screening tool for microalgal biofuel development.
- Published
- 2017
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37. Unformulated experience, dissociation, and Nachträglichkeit.
- Author
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Stern DB
- Subjects
- Humans, Dissociative Disorders, Psychoanalytic Theory, Psychological Trauma
- Abstract
The paper is divided into two parts. The first part is an interpersonal/relational psychoanalytic account of some relationships between dissociation, time, and unformulated experience. Trauma, and the dissociation to which trauma leads, freezes time, which makes it impossible to formulate certain kinds of new experience. Instead, potential new meanings remain unformulated. The route of clinical access to frozen time is the interpersonal field: to thaw time and allow new experience, the ways in which the interpersonal field is itself frozen need to be addressed. A clinical illustration of these ideas is offered. The second part of the paper presents and explores a point of confluence between the views in Part 1 and certain aspects of French psychoanalysis, with particular reference to the concept of Nachträglichkeit in the work of Jean Laplanche and Haydée Faimberg., (© 2017, The Society of Analytical Psychology.)
- Published
- 2017
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38. DNA Barcoding analysis of seafood accuracy in Washington, D.C. restaurants.
- Author
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Stern DB, Castro Nallar E, Rathod J, and Crandall KA
- Abstract
In Washington D.C., recent legislation authorizes citizens to test if products are properly represented and, if they are not, to bring a lawsuit for the benefit of the general public. Recent studies revealing the widespread phenomenon of seafood substitution across the United States make it a fertile area for consumer protection testing. DNA barcoding provides an accurate and cost-effective way to perform these tests, especially when tissue alone is available making species identification based on morphology impossible. In this study, we sequenced the 5' barcoding region of the Cytochrome Oxidase I gene for 12 samples of vertebrate and invertebrate food items across six restaurants in Washington, D.C. and used multiple analytical methods to make identifications. These samples included several ambiguous menu listings, sequences with little genetic variation among closely related species and one sequence with no available reference sequence. Despite these challenges, we were able to make identifications for all samples and found that 33% were potentially mislabeled. While we found a high degree of mislabeling, the errors involved closely related species and we did not identify egregious substitutions as have been found in other cities. This study highlights the efficacy of DNA barcoding and robust analyses in identifying seafood items for consumer protection., Competing Interests: Keith Crandall is an Academic Editor for PeerJ. Jason Rathod is an employee of Migliaccio & Rathod LLP.
- Published
- 2017
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39. ChloroSeq, an Optimized Chloroplast RNA-Seq Bioinformatic Pipeline, Reveals Remodeling of the Organellar Transcriptome Under Heat Stress.
- Author
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Castandet B, Hotto AM, Strickler SR, and Stern DB
- Subjects
- Arabidopsis metabolism, Computational Biology, Heat-Shock Response genetics, Hot Temperature, RNA, Chloroplast metabolism, Arabidopsis genetics, Chloroplasts genetics, RNA, Chloroplast genetics, Transcriptome genetics
- Abstract
Although RNA-Seq has revolutionized transcript analysis, organellar transcriptomes are rarely assessed even when present in published datasets. Here, we describe the development and application of a rapid and convenient method, ChloroSeq, to delineate qualitative and quantitative features of chloroplast RNA metabolism from strand-specific RNA-Seq datasets, including processing, editing, splicing, and relative transcript abundance. The use of a single experiment to analyze systematically chloroplast transcript maturation and abundance is of particular interest due to frequent pleiotropic effects observed in mutants that affect chloroplast gene expression and/or photosynthesis. To illustrate its utility, ChloroSeq was applied to published RNA-Seq datasets derived from Arabidopsis thaliana grown under control and abiotic stress conditions, where the organellar transcriptome had not been examined. The most appreciable effects were found for heat stress, which induces a global reduction in splicing and editing efficiency, and leads to increased abundance of chloroplast transcripts, including genic, intergenic, and antisense transcripts. Moreover, by concomitantly analyzing nuclear transcripts that encode chloroplast gene expression regulators from the same libraries, we demonstrate the possibility of achieving a holistic understanding of the nucleus-organelle system. ChloroSeq thus represents a unique method for streamlining RNA-Seq data interpretation of the chloroplast transcriptome and its regulators., (Copyright © 2016 Castandet et al.)
- Published
- 2016
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40. Activation of an Endoribonuclease by Non-intein Protein Splicing.
- Author
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Campbell SJ and Stern DB
- Subjects
- Chlamydomonas reinhardtii genetics, Chloroplast Proteins genetics, Chloroplasts genetics, Endonucleases genetics, Protein Splicing physiology, Chlamydomonas reinhardtii enzymology, Chloroplast Proteins metabolism, Chloroplasts enzymology, Endonucleases metabolism, Light, Protein Splicing radiation effects
- Abstract
The Chlamydomonas reinhardtii chloroplast-localized poly(A)-binding protein RB47 is predicted to contain a non-conserved linker (NCL) sequence flanked by highly conserved N- and C-terminal sequences, based on the corresponding cDNA. RB47 was purified from chloroplasts in association with an endoribonuclease activity; however, protein sequencing failed to detect the NCL. Furthermore, while recombinant RB47 including the NCL did not display endoribonuclease activity in vitro, versions lacking the NCL displayed strong activity. Both full-length and shorter forms of RB47 could be detected in chloroplasts, with conversion to the shorter form occurring in chloroplasts isolated from cells grown in the light. This conversion could be replicated in vitro in chloroplast extracts in a light-dependent manner, where epitope tags and protein sequencing showed that the NCL was excised from a full-length recombinant substrate, together with splicing of the flanking sequences. The requirement for endogenous factors and light differentiates this protein splicing from autocatalytic inteins, and may allow the chloroplast to regulate the activation of RB47 endoribonuclease activity. We speculate that this protein splicing activity arose to post-translationally repair proteins that had been inactivated by deleterious insertions or extensions., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Published
- 2016
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41. Age-related striatal BOLD changes without changes in behavioral loss aversion.
- Author
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Viswanathan V, Lee S, Gilman JM, Kim BW, Lee N, Chamberlain L, Livengood SL, Raman K, Lee MJ, Kuster J, Stern DB, Calder B, Mulhern FJ, Blood AJ, and Breiter HC
- Abstract
Loss aversion (LA), the idea that negative valuations have a higher psychological impact than positive ones, is considered an important variable in consumer research. The literature on aging and behavior suggests older individuals may show more LA, although it is not clear if this is an effect of aging in general (as in the continuum from age 20 and 50 years), or of the state of older age (e.g., past age 65 years). We also have not yet identified the potential biological effects of aging on the neural processing of LA. In the current study we used a cohort of subjects with a 30 year range of ages, and performed whole brain functional MRI (fMRI) to examine the ventral striatum/nucleus accumbens (VS/NAc) response during a passive viewing of affective faces with model-based fMRI analysis incorporating behavioral data from a validated approach/avoidance task with the same stimuli. Our a priori focus on the VS/NAc was based on (1) the VS/NAc being a central region for reward/aversion processing; (2) its activation to both positive and negative stimuli; (3) its reported involvement with tracking LA. LA from approach/avoidance to affective faces showed excellent fidelity to published measures of LA. Imaging results were then compared to the behavioral measure of LA using the same affective faces. Although there was no relationship between age and LA, we observed increasing neural differential sensitivity (NDS) of the VS/NAc to avoidance responses (negative valuations) relative to approach responses (positive valuations) with increasing age. These findings suggest that a central region for reward/aversion processing changes with age, and may require more activation to produce the same LA behavior as in younger individuals, consistent with the idea of neural efficiency observed with high IQ individuals showing less brain activation to complete the same task.
- Published
- 2015
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42. Arabidopsis chloroplast mini-ribonuclease III participates in rRNA maturation and intron recycling.
- Author
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Hotto AM, Castandet B, Gilet L, Higdon A, Condon C, and Stern DB
- Subjects
- Amino Acid Sequence, Arabidopsis Proteins chemistry, Arabidopsis Proteins genetics, Bacillus subtilis metabolism, Base Sequence, Evolution, Molecular, Exons genetics, Genetic Complementation Test, Models, Biological, Molecular Sequence Data, Mutation genetics, Polyribosomes metabolism, Protein Structure, Tertiary, RNA Stability, RNA, Ribosomal metabolism, RNA, Ribosomal, 23S genetics, RNA, Untranslated genetics, Ribosomes metabolism, Sequence Analysis, RNA, Sequence Homology, Amino Acid, Transgenes, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Chloroplasts metabolism, Introns genetics, RNA, Ribosomal genetics, Ribonuclease III metabolism
- Abstract
RNase III proteins recognize double-stranded RNA structures and catalyze endoribonucleolytic cleavages that often regulate gene expression. Here, we characterize the functions of RNC3 and RNC4, two Arabidopsis thaliana chloroplast Mini-RNase III-like enzymes sharing 75% amino acid sequence identity. Whereas rnc3 and rnc4 null mutants have no visible phenotype, rnc3/rnc4 (rnc3/4) double mutants are slightly smaller and chlorotic compared with the wild type. In Bacillus subtilis, the RNase Mini-III is integral to 23S rRNA maturation. In Arabidopsis, we observed imprecise maturation of 23S rRNA in the rnc3/4 double mutant, suggesting that exoribonucleases generated staggered ends in the absence of specific Mini-III-catalyzed cleavages. A similar phenotype was found at the 3' end of the 16S rRNA, and the primary 4.5S rRNA transcript contained 3' extensions, suggesting that Mini-III catalyzes several processing events of the polycistronic rRNA precursor. The rnc3/4 mutant showed overaccumulation of a noncoding RNA complementary to the 4.5S-5S rRNA intergenic region, and its presence correlated with that of the extended 4.5S rRNA precursor. Finally, we found rnc3/4-specific intron degradation intermediates that are probable substrates for Mini-III and show that B. subtilis Mini-III is also involved in intron regulation. Overall, this study extends our knowledge of the key role of Mini-III in intron and noncoding RNA regulation and provides important insight into plastid rRNA maturation., (© 2015 American Society of Plant Biologists. All rights reserved.)
- Published
- 2015
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43. Redefining neuromarketing as an integrated science of influence.
- Author
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Breiter HC, Block M, Blood AJ, Calder B, Chamberlain L, Lee N, Livengood S, Mulhern FJ, Raman K, Schultz D, Stern DB, Viswanathan V, and Zhang FZ
- Abstract
Multiple transformative forces target marketing, many of which derive from new technologies that allow us to sample thinking in real time (i.e., brain imaging), or to look at large aggregations of decisions (i.e., big data). There has been an inclination to refer to the intersection of these technologies with the general topic of marketing as "neuromarketing". There has not been a serious effort to frame neuromarketing, which is the goal of this paper. Neuromarketing can be compared to neuroeconomics, wherein neuroeconomics is generally focused on how individuals make "choices", and represent distributions of choices. Neuromarketing, in contrast, focuses on how a distribution of choices can be shifted or "influenced", which can occur at multiple "scales" of behavior (e.g., individual, group, or market/society). Given influence can affect choice through many cognitive modalities, and not just that of valuation of choice options, a science of influence also implies a need to develop a model of cognitive function integrating attention, memory, and reward/aversion function. The paper concludes with a brief description of three domains of neuromarketing application for studying influence, and their caveats.
- Published
- 2015
- Full Text
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44. A protein with an inactive pterin-4a-carbinolamine dehydratase domain is required for Rubisco biogenesis in plants.
- Author
-
Feiz L, Williams-Carrier R, Belcher S, Montano M, Barkan A, and Stern DB
- Subjects
- Chloroplasts metabolism, Cross-Linking Reagents chemistry, DNA Transposable Elements, Hydro-Lyases genetics, Immunoprecipitation, Mutation, Plant Leaves chemistry, Plant Leaves genetics, Plant Leaves metabolism, Plant Proteins genetics, Protein Structure, Tertiary, Ribulose-Bisphosphate Carboxylase genetics, Zea mays genetics, Hydro-Lyases metabolism, Plant Proteins metabolism, Ribulose-Bisphosphate Carboxylase metabolism
- Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) plays a critical role in sustaining life by catalysis of carbon fixation in the Calvin-Benson pathway. Incomplete knowledge of the assembly pathway of chloroplast Rubisco has hampered efforts to fully delineate the enzyme's properties, or seek improved catalytic characteristics via directed evolution. Here we report that a Mu transposon insertion in the Zea mays (maize) gene encoding a chloroplast dimerization co-factor of hepatocyte nuclear factor 1 (DCoH)/pterin-4α-carbinolamine dehydratases (PCD)-like protein is the causative mutation in a seedling-lethal, Rubisco-deficient mutant named Rubisco accumulation factor 2 (raf2-1). In raf2 mutants newly synthesized Rubisco large subunit accumulates in a high-molecular weight complex, the formation of which requires a specific chaperonin 60-kDa isoform. Analogous observations had been made previously with maize mutants lacking the Rubisco biogenesis proteins RAF1 and BSD2. Chemical cross-linking of maize leaves followed by immunoprecipitation with antibodies to RAF2, RAF1 or BSD2 demonstrated co-immunoprecipitation of each with Rubisco small subunit, and to a lesser extent, co-immunoprecipitation with Rubisco large subunit. We propose that RAF2, RAF1 and BSD2 form transient complexes with the Rubisco small subunit, which in turn assembles with the large subunit as it is released from chaperonins., (© 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.)
- Published
- 2014
- Full Text
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45. A response to LaFarge.
- Author
-
Stern DB
- Subjects
- Humans, Fantasy, Psychoanalysis, Psychoanalytic Therapy, Transference, Psychology
- Published
- 2014
- Full Text
- View/download PDF
46. The relationship between self-report of depression and media usage.
- Author
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Block M, Stern DB, Raman K, Lee S, Carey J, Humphreys AA, Mulhern F, Calder B, Schultz D, Rudick CN, Blood AJ, and Breiter HC
- Abstract
Depression is a debilitating condition that adversely affects many aspects of a person's life and general health. Earlier work has supported the idea that there may be a relationship between the use of certain media and depression. In this study, we tested if self-report of depression (SRD), which is not a clinically based diagnosis, was associated with increased internet, television, and social media usage by using data collected in the Media Behavior and Influence Study (MBIS) database (N = 19,776 subjects). We further assessed the relationship of demographic variables to this association. These analyses found that SRD rates were in the range of published rates of clinically diagnosed major depression. It found that those who tended to use more media also tended to be more depressed, and that segmentation of SRD subjects was weighted toward internet and television usage, which was not the case with non-SRD subjects, who were segmented along social media use. This study found that those who have suffered either economic or physical life setbacks are orders of magnitude more likely to be depressed, even without disproportionately high levels of media use. However, among those that have suffered major life setbacks, high media users-particularly television watchers-were even more likely to report experiencing depression, which suggests that these effects were not just due to individuals having more time for media consumption. These findings provide an example of how Big Data can be used for medical and mental health research, helping to elucidate issues not traditionally tested in the fields of psychiatry or experimental psychology.
- Published
- 2014
- Full Text
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47. RNase J participates in a pentatricopeptide repeat protein-mediated 5' end maturation of chloroplast mRNAs.
- Author
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Luro S, Germain A, Sharwood RE, and Stern DB
- Subjects
- Plant Proteins genetics, Plant Proteins physiology, RNA, Transfer genetics, RNA-Binding Proteins genetics, RNA-Binding Proteins physiology, Ribonucleases physiology, Nicotiana anatomy & histology, Nicotiana genetics, Nicotiana metabolism, Gene Expression Regulation, Plant, Plant Proteins metabolism, RNA Processing, Post-Transcriptional, RNA, Chloroplast metabolism, RNA, Messenger metabolism, RNA-Binding Proteins metabolism, Ribonucleases metabolism
- Abstract
Nucleus-encoded ribonucleases and RNA-binding proteins influence chloroplast gene expression through their roles in RNA maturation and stability. One mechanism for mRNA 5' end maturation posits that sequence-specific pentatricopeptide repeat (PPR) proteins define termini by blocking the 5'→3' exonucleolytic activity of ribonuclease J (RNase J). To test this hypothesis in vivo, virus-induced gene silencing was used to reduce the expression of three PPR proteins and RNase J, both individually and jointly, in Nicotiana benthamiana. In accordance with the stability-conferring function of the PPR proteins PPR10, HCF152 and MRL1, accumulation of the cognate RNA species atpH, petB and rbcL was reduced when the PPR-encoding genes were silenced. In contrast, RNase J reduction alone or combined with PPR deficiency resulted in reduced abundance of polycistronic precursor transcripts and mature counterparts, which were replaced by intermediately sized species with heterogeneous 5' ends. We conclude that RNase J deficiency can partially mask the absence of PPR proteins, and that RNase J is capable of processing chloroplast mRNAs up to PPR protein-binding sites. These findings support the hypothesis that RNase J is the major ribonuclease responsible for maturing chloroplast mRNA 5' termini, with RNA-binding proteins acting as barriers to its activity.
- Published
- 2013
- Full Text
- View/download PDF
48. Strand-specific RNA sequencing uncovers chloroplast ribonuclease functions.
- Author
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Castandet B, Hotto AM, Fei Z, and Stern DB
- Subjects
- Arabidopsis genetics, Chloroplasts genetics, Exoribonucleases genetics, Plant Proteins genetics, RNA Precursors genetics, RNA Precursors metabolism, RNA, Chloroplast genetics, RNA, Transfer genetics, RNA, Transfer metabolism, Sequence Analysis, RNA methods, Transcription Initiation Site, Transcription Initiation, Genetic, Untranslated Regions, Arabidopsis metabolism, Chloroplasts metabolism, Exoribonucleases metabolism, Gene Expression Regulation, Plant, Plant Proteins metabolism, RNA, Chloroplast metabolism
- Abstract
Organellar gene expression incorporates ribonucleases as indispensable participants. Here, we explored the capacity of strand-specific RNA sequencing (RNA-Seq) as a tool to analyze chloroplast ribonuclease functions using the 3'→5' exoribonuclease polynucleotide phosphorylase (PNPase) as a proof of concept. The role of PNPase in transcript 3' end maturation was easily monitored, and additional targeted mRNAs were discovered. Moreover, a role in tRNA precursor degradation was predicted and validated. These results, together with previously published data, suggest that RNA-Seq represents a unique opportunity to decipher the roles of organellar ribonucleases and deepen our understanding of chloroplast gene expression., (Copyright © 2013. Published by Elsevier B.V.)
- Published
- 2013
- Full Text
- View/download PDF
49. Arabidopsis chloroplast quantitative editotype.
- Author
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Ruwe H, Castandet B, Schmitz-Linneweber C, and Stern DB
- Subjects
- Arabidopsis enzymology, Arabidopsis genetics, Base Sequence, Polyribonucleotide Nucleotidyltransferase deficiency, Transcriptome, Arabidopsis cytology, Chloroplasts genetics, RNA Editing, RNA, Plant genetics
- Abstract
Chloroplast C-to-U RNA editing is an essential post-transcriptional process. Here we analyzed RNA editing in Arabidopsis thaliana using strand-specific deep sequencing datasets from the wild-type and a mutant defective in RNA 3' end maturation. We demonstrate that editing at all sites is partial, with an average of 5-6% of RNAs remaining unedited. Furthermore, we identified nine novel sites with a low extent of editing. Of these, three sites are absent from the WT transcriptome because they are removed by 3' end RNA processing, but these regions accumulate, and are edited, in a mutant lacking polynucleotide phosphorylase., (Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
50. RNA processing and decay in plastids.
- Author
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Germain A, Hotto AM, Barkan A, and Stern DB
- Subjects
- Gene Expression Regulation, Plant, Plant Proteins metabolism, Plastids genetics, Plastids metabolism, Plastids physiology, RNA Processing, Post-Transcriptional, RNA Stability
- Abstract
Plastids were derived through endosymbiosis from a cyanobacterial ancestor, whose uptake was followed by massive gene transfer to the nucleus, resulting in the compact size and modest coding capacity of the extant plastid genome. Plastid gene expression is essential for plant development, but depends on nucleus-encoded proteins recruited from cyanobacterial or host-cell origins. The plastid genome is heavily transcribed from numerous promoters, giving posttranscriptional events a critical role in determining the quantity and sizes of accumulating RNA species. The major events reviewed here are RNA editing, which restores protein conservation or creates correct open reading frames by converting C residues to U, RNA splicing, which occurs both in cis and trans, and RNA cleavage, which relies on a variety of exoribonucleases and endoribonucleases. Because the RNases have little sequence specificity, they are collectively able to remove extraneous RNAs whose ends are not protected by RNA secondary structures or sequence-specific RNA-binding proteins (RBPs). Other plastid RBPs, largely members of the helical-repeat superfamily, confer specificity to editing and splicing reactions. The enzymes that catalyze RNA processing are also the main actors in RNA decay, implying that these antagonistic roles are optimally balanced. We place the actions of RBPs and RNases in the context of a recent proteomic analysis that identifies components of the plastid nucleoid, a protein-DNA complex with multiple roles in gene expression. These results suggest that sublocalization and/or concentration gradients of plastid proteins could underpin the regulation of RNA maturation and degradation., (Copyright © 2013 John Wiley & Sons, Ltd.)
- Published
- 2013
- Full Text
- View/download PDF
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