The Nucleosome Remodeling and Deacetylase (NuRD) Complex in Development and Disease

PubMed Central

Basta, Jeannine; Rauchman, Michael

2014-01-01

The Nucleosome Remodeling and Deacetylase (NuRD) complex is one of the major chromatin remodeling complexes found in cells. It plays an important role in regulating gene transcription, genome integrity and cell cycle progression. Through its impact on these basic cellular processes, increasing evidence indicates that alterations in the activity of this macromolecular complex can lead to developmental defects, oncogenesis and accelerated ageing. Recent genetic and biochemical studies have elucidated the mechanisms of NuRD action in modifying the chromatin landscape. These advances have the potential to lead to new therapeutic approaches to birth defects and cancer. PMID:24880148

DREAMs make plant cells to cycle or to become quiescent.

PubMed

Magyar, Zoltán; Bögre, László; Ito, Masaki

2016-12-01

Cell cycle phase specific oscillation of gene transcription has long been recognized as an underlying principle for ordered processes during cell proliferation. The G1/S-specific and G2/M-specific cohorts of genes in plants are regulated by the E2F and the MYB3R transcription factors. Mutant analysis suggests that activator E2F functions might not be fully required for cell cycle entry. In contrast, the two activator-type MYB3Rs are part of positive feedback loops to drive the burst of mitotic gene expression, which is necessary at least to accomplish cytokinesis. Repressor MYB3Rs act outside the mitotic time window during cell cycle progression, and are important for the shutdown of mitotic genes to impose quiescence in mature organs. The two distinct classes of E2Fs and MYB3Rs together with the RETINOBLATOMA RELATED are part of multiprotein complexes that may be evolutionary related to what is known as DREAM complex in animals. In plants, there are multiple such complexes with distinct compositions and functions that may be involved in the coordinated cell cycle and developmental regulation of E2F targets and mitotic genes. Copyright © 2016 Elsevier Ltd. All rights reserved.

TelAP1 links telomere complexes with developmental expression site silencing in African trypanosomes

PubMed Central

Reis, Helena; Schwebs, Marie; Dietz, Sabrina; Janzen, Christian J; Butter, Falk

2018-01-01

Abstract During its life cycle, Trypanosoma brucei shuttles between a mammalian host and the tsetse fly vector. In the mammalian host, immune evasion of T. brucei bloodstream form (BSF) cells relies on antigenic variation, which includes monoallelic expression and periodic switching of variant surface glycoprotein (VSG) genes. The active VSG is transcribed from only 1 of the 15 subtelomeric expression sites (ESs). During differentiation from BSF to the insect-resident procyclic form (PCF), the active ES is transcriptionally silenced. We used mass spectrometry-based interactomics to determine the composition of telomere protein complexes in T. brucei BSF and PCF stages to learn more about the structure and functions of telomeres in trypanosomes. Our data suggest a different telomere complex composition in the two forms of the parasite. One of the novel telomere-associated proteins, TelAP1, forms a complex with telomeric proteins TbTRF, TbRAP1 and TbTIF2 and influences ES silencing kinetics during developmental differentiation. PMID:29385523

Germline mutations affecting the histone H4 core cause a developmental syndrome by altering DNA damage response and cell cycle control.

PubMed

Tessadori, Federico; Giltay, Jacques C; Hurst, Jane A; Massink, Maarten P; Duran, Karen; Vos, Harmjan R; van Es, Robert M; Scott, Richard H; van Gassen, Koen L I; Bakkers, Jeroen; van Haaften, Gijs

2017-11-01

Covalent modifications of histones have an established role as chromatin effectors, as they control processes such as DNA replication and transcription, and repair or regulate nucleosomal structure. Loss of modifications on histone N tails, whether due to mutations in genes belonging to histone-modifying complexes or mutations directly affecting the histone tails, causes developmental disorders or has a role in tumorigenesis. More recently, modifications affecting the globular histone core have been uncovered as being crucial for DNA repair, pluripotency and oncogenesis. Here we report monoallelic missense mutations affecting lysine 91 in the histone H4 core (H4K91) in three individuals with a syndrome of growth delay, microcephaly and intellectual disability. Expression of the histone H4 mutants in zebrafish embryos recapitulates the developmental anomalies seen in the patients. We show that the histone H4 alterations cause genomic instability, resulting in increased apoptosis and cell cycle progression anomalies during early development. Mechanistically, our findings indicate an important role for the ubiquitination of H4K91 in genomic stability during embryonic development.

Hydrozoan insights in animal development and evolution.

PubMed

Leclère, Lucas; Copley, Richard R; Momose, Tsuyoshi; Houliston, Evelyn

2016-08-01

The fresh water polyp Hydra provides textbook experimental demonstration of positional information gradients and regeneration processes. Developmental biologists are thus familiar with Hydra, but may not appreciate that it is a relatively simple member of the Hydrozoa, a group of mostly marine cnidarians with complex and diverse life cycles, exhibiting extensive phenotypic plasticity and regenerative capabilities. Hydrozoan species offer extensive opportunities to address many developmental mechanisms relevant across the animal kingdom. Here we review recent work from non-Hydra hydrozoans - hydromedusae, hydroids and siphonophores - shedding light on mechanisms of oogenesis, embryonic patterning, allorecognition, stem cell regulation and regeneration. We also highlight potential research directions in which hydrozoan diversity can illuminate the evolution of developmental processes at micro- and macro-evolutionary time scales. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Oedipus Cycle: developmental mythology, Greek tragedy, and the sociology of knowledge.

PubMed

Datan, N

1988-01-01

The Oedipus complex of Freud is based on the inevitability of the tragic fate of a man who fled his home to escape the prophecy of parricide. Thus, he fulfilled it by killing a stranger who proved to be his father. As Freud does, this consideration of the tragedy of Oedipus takes as its point of departure the inevitability of the confrontation between father and son. Where Freud looks to the son, however, I look to the father, who set the tragedy in motion by attempting to murder his infant son. Themes ignored in developmental theory but axiomatic in gerontology are considered in this study of the elder Oedipus. The study begins by noting that Oedipus ascended the throne of Thebes not by parricide but by answering the riddle of the Sphynx and affirming the continuity of the life cycle which his father denied. In the second tragedy of the Oedipus Cycle of Sophocles, Oedipus at Colonus, this affirmation is maintained. As Oedipus the elder accepts the infirmities of old age and the support of his daughter Antigone, Oedipus the king proves powerful up to the very end of his life when he gives his blessing not to the sons who had exiled him from Thebes, but to King Theseus who shelters him in his old age. Thus, the Oedipus cycle, in contrast to the "Oedipus complex," represents not the unconscious passions of the small boy, but rather the awareness of the life cycle in the larger context of the succession of the generations and their mutual interdependence. These themes are illuminated by a fuller consideration of the tragedy of Oedipus.

Transcriptome profiling of the dynamic life cycle of the scypohozoan jellyfish Aurelia aurita.

PubMed

Brekhman, Vera; Malik, Assaf; Haas, Brian; Sher, Noa; Lotan, Tamar

2015-02-14

The moon jellyfish Aurelia aurita is a widespread scyphozoan species that forms large seasonal blooms. Here we provide the first comprehensive view of the entire complex life of the Aurelia Red Sea strain by employing transcriptomic profiling of each stage from planula to mature medusa. A de novo transcriptome was assembled from Illumina RNA-Seq data generated from six stages throughout the Aurelia life cycle. Transcript expression profiling yielded clusters of annotated transcripts with functions related to each specific life-cycle stage. Free-swimming planulae were found highly enriched for functions related to cilia and microtubules, and the drastic morphogenetic process undergone by the planula while establishing the future body of the polyp may be mediated by specifically expressed Wnt ligands. Specific transcripts related to sensory functions were found in the strobila and the ephyra, whereas extracellular matrix functions were enriched in the medusa due to high expression of transcripts such as collagen, fibrillin and laminin, presumably involved in mesoglea development. The CL390-like gene, suggested to act as a strobilation hormone, was also highly expressed in the advanced strobila of the Red Sea species, and in the medusa stage we identified betaine-homocysteine methyltransferase, an enzyme that may play an important part in maintaining equilibrium of the medusa's bell. Finally, we identified the transcription factors participating in the Aurelia life-cycle and found that 70% of these 487 identified transcription factors were expressed in a developmental-stage-specific manner. This study provides the first scyphozoan transcriptome covering the entire developmental trajectory of the life cycle of Aurelia. It highlights the importance of numerous stage-specific transcription factors in driving morphological and functional changes throughout this complex metamorphosis, and is expected to be a valuable resource to the community.

Parental effects in ecology and evolution: mechanisms, processes and implications

PubMed Central

Badyaev, Alexander V.; Uller, Tobias

2009-01-01

As is the case with any metaphor, parental effects mean different things to different biologists—from developmental induction of novel phenotypic variation to an evolved adaptation, and from epigenetic transference of essential developmental resources to a stage of inheritance and ecological succession. Such a diversity of perspectives illustrates the composite nature of parental effects that, depending on the stage of their expression and whether they are considered a pattern or a process, combine the elements of developmental induction, homeostasis, natural selection, epigenetic inheritance and historical persistence. Here, we suggest that by emphasizing the complexity of causes and influences in developmental systems and by making explicit the links between development, natural selection and inheritance, the study of parental effects enables deeper understanding of developmental dynamics of life cycles and provides a unique opportunity to explicitly integrate development and evolution. We highlight these perspectives by placing parental effects in a wider evolutionary framework and suggest that far from being only an evolved static outcome of natural selection, a distinct channel of transmission between parents and offspring, or a statistical abstraction, parental effects on development enable evolution by natural selection by reliably transferring developmental resources needed to reconstruct, maintain and modify genetically inherited components of the phenotype. The view of parental effects as an essential and dynamic part of an evolutionary continuum unifies mechanisms behind the origination, modification and historical persistence of organismal form and function, and thus brings us closer to a more realistic understanding of life's complexity and diversity. PMID:19324619

Developmental plasticity in schistosomes and other helminths

PubMed Central

Davies, Stephen J.; McKerrow, James H.

2010-01-01

Developmental plasticity in helminth life cycles serves, in most cases, to increase the probability of transmission between hosts, suggesting that the necessity to achieve transmission is a prominent selective pressure in the evolution of this phenomenon. Some evidence suggests that digenean trematodes from the genus Schistosoma are also capable of limited developmental responses to host factors. Here we review the currently available data on this phenomenon and attempt to draw comparisons with similar processes in the life cycles of other helminths. At present the biological significance of developmental responses by schistosomes under laboratory conditions remains unclear. Further work is needed to determine whether developmental plasticity plays any role in increasing the probability of schistosome transmission and life cycle propagation under adverse conditions, as it does in other helminth life cycles. PMID:13678642

The plant cell cycle: Pre-Replication complex formation and controls

PubMed Central

Brasil, Juliana Nogueira; Costa, Carinne N. Monteiro; Cabral, Luiz Mors; Ferreira, Paulo C. G.; Hemerly, Adriana S.

2017-01-01

Abstract The multiplication of cells in all living organisms requires a tight regulation of DNA replication. Several mechanisms take place to ensure that the DNA is replicated faithfully and just once per cell cycle in order to originate through mitoses two new daughter cells that contain exactly the same information from the previous one. A key control mechanism that occurs before cells enter S phase is the formation of a pre-replication complex (pre-RC) that is assembled at replication origins by the sequential association of the origin recognition complex, followed by Cdt1, Cdc6 and finally MCMs, licensing DNA to start replication. The identification of pre-RC members in all animal and plant species shows that this complex is conserved in eukaryotes and, more importantly, the differences between kingdoms might reflect their divergence in strategies on cell cycle regulation, as it must be integrated and adapted to the niche, ecosystem, and the organism peculiarities. Here, we provide an overview of the knowledge generated so far on the formation and the developmental controls of the pre-RC mechanism in plants, analyzing some particular aspects in comparison to other eukaryotes. PMID:28304073

Polycomb group protein complexes exchange rapidly in living Drosophila.

PubMed

Ficz, Gabriella; Heintzmann, Rainer; Arndt-Jovin, Donna J

2005-09-01

Fluorescence recovery after photobleaching (FRAP) microscopy was used to determine the kinetic properties of Polycomb group (PcG) proteins in whole living Drosophila organisms (embryos) and tissues (wing imaginal discs and salivary glands). PcG genes are essential genes in higher eukaryotes responsible for the maintenance of the spatially distinct repression of developmentally important regulators such as the homeotic genes. Their absence, as well as overexpression, causes transformations in the axial organization of the body. Although protein complexes have been isolated in vitro, little is known about their stability or exact mechanism of repression in vivo. We determined the translational diffusion constants of PcG proteins, dissociation constants and residence times for complexes in vivo at different developmental stages. In polytene nuclei, the rate constants suggest heterogeneity of the complexes. Computer simulations with new models for spatially distributed protein complexes were performed in systems showing both diffusion and binding equilibria, and the results compared with our experimental data. We were able to determine forward and reverse rate constants for complex formation. Complexes exchanged within a period of 1-10 minutes, more than an order of magnitude faster than the cell cycle time, ruling out models of repression in which access of transcription activators to the chromatin is limited and demonstrating that long-term repression primarily reflects mass-action chemical equilibria.

Transcriptome profiling of the demosponge Amphimedon queenslandica reveals genome-wide events that accompany major life cycle transitions

PubMed Central

2012-01-01

Background The biphasic life cycle with pelagic larva and benthic adult stages is widely observed in the animal kingdom, including the Porifera (sponges), which are the earliest branching metazoans. The demosponge, Amphimedon queenslandica, undergoes metamorphosis from a free-swimming larva into a sessile adult that bears no morphological resemblance to other animals. While the genome of A. queenslandica contains an extensive repertoire of genes very similar to that of complex bilaterians, it is as yet unclear how this is drawn upon to coordinate changing morphological features and ecological demands throughout the sponge life cycle. Results To identify genome-wide events that accompany the pelagobenthic transition in A. queenslandica, we compared global gene expression profiles at four key developmental stages by sequencing the poly(A) transcriptome using SOLiD technology. Large-scale changes in transcription were observed as sponge larvae settled on the benthos and began metamorphosis. Although previous systematics suggest that the only clear homology between Porifera and other animals is in the embryonic and larval stages, we observed extensive use of genes involved in metazoan-associated cellular processes throughout the sponge life cycle. Sponge-specific transcripts are not over-represented in the morphologically distinct adult; rather, many genes that encode typical metazoan features, such as cell adhesion and immunity, are upregulated. Our analysis further revealed gene families with candidate roles in competence, settlement, and metamorphosis in the sponge, including transcription factors, G-protein coupled receptors and other signaling molecules. Conclusions This first genome-wide study of the developmental transcriptome in an early branching metazoan highlights major transcriptional events that accompany the pelagobenthic transition and point to a network of regulatory mechanisms that coordinate changes in morphology with shifting environmental demands. Metazoan developmental and structural gene orthologs are well-integrated into the expression profiles at every stage of sponge development, including the adult. The utilization of genes involved in metazoan-associated processes throughout sponge development emphasizes the potential of the genome of the last common ancestor of animals to generate phenotypic complexity. PMID:22646746

The filamentous fungus Sordaria macrospora as a genetic model to study fruiting body development.

PubMed

Teichert, Ines; Nowrousian, Minou; Pöggeler, Stefanie; Kück, Ulrich

2014-01-01

Filamentous fungi are excellent experimental systems due to their short life cycles as well as easy and safe manipulation in the laboratory. They form three-dimensional structures with numerous different cell types and have a long tradition as genetic model organisms used to unravel basic mechanisms underlying eukaryotic cell differentiation. The filamentous ascomycete Sordaria macrospora is a model system for sexual fruiting body (perithecia) formation. S. macrospora is homothallic, i.e., self-fertile, easily genetically tractable, and well suited for large-scale genomics, transcriptomics, and proteomics studies. Specific features of its life cycle and the availability of a developmental mutant library make it an excellent system for studying cellular differentiation at the molecular level. In this review, we focus on recent developments in identifying gene and protein regulatory networks governing perithecia formation. A number of tools have been developed to genetically analyze developmental mutants and dissect transcriptional profiles at different developmental stages. Protein interaction studies allowed us to identify a highly conserved eukaryotic multisubunit protein complex, the striatin-interacting phosphatase and kinase complex and its role in sexual development. We have further identified a number of proteins involved in chromatin remodeling and transcriptional regulation of fruiting body development. Furthermore, we review the involvement of metabolic processes from both primary and secondary metabolism, and the role of nutrient recycling by autophagy in perithecia formation. Our research has uncovered numerous players regulating multicellular development in S. macrospora. Future research will focus on mechanistically understanding how these players are orchestrated in this fungal model system. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparative muscle development of scyphozoan jellyfish with simple and complex life cycles.

PubMed

Helm, Rebecca R; Tiozzo, Stefano; Lilley, Martin K S; Lombard, Fabien; Dunn, Casey W

2015-01-01

Simple life cycles arise from complex life cycles when one or more developmental stages are lost. This raises a fundamental question - how can an intermediate stage, such as a larva, be removed, and development still produce a normal adult? To address this question, we examined the development in several species of pelagiid jellyfish. Most members of Pelagiidae have a complex life cycle with a sessile polyp that gives rise to ephyrae (juvenile medusae); but one species within Pelagiidae, Pelagia noctiluca, spends its whole life in the water column, developing from a larva directly into an ephyra. In many complex life cycles, adult features develop from cell populations that remain quiescent in larvae, and this is known as life cycle compartmentalization and may facilitate the evolution of direct life cycles. A second type of metamorphic processes, known as remodeling, occurs when adult features are formed through modification of already differentiated larval structures. We examined muscle morphology to determine which of these alternatives may be present in Pelagiidae. We first examined the structure and development of polyp and ephyra musculature in Chrysaora quinquecirrha, a close relative of P. noctiluca with a complex life cycle. Using phallotoxin staining and confocal microscopy, we verified that polyps have four to six cord muscles that persist in strobilae and discovered that cord muscles is physically separated from ephyra muscle. When cord muscle is removed from ephyra segments, normal ephyra muscle still develops. This suggests that polyp cord muscle is not necessary for ephyra muscle formation. We also found no evidence of polyp-like muscle in P. noctiluca. In both species, we discovered that ephyra muscle arises de novo in a similar manner, regardless of the life cycle. The separate origins of polyp and ephyra muscle in C. quinquecirrha and the absence of polyp-like muscle in P. noctiluca suggest that polyp muscle is not remodeled to form ephyra muscle in Pelagiidae. Life cycle stages in Scyphozoa may instead be compartmentalized. Because polyp muscle is not directly remodeled, this may have facilitated the loss of the polyp stage in the evolution of P. noctiluca.

Species diversity vs. morphological disparity in the light of evolutionary developmental biology

PubMed Central

Minelli, Alessandro

2016-01-01

Background Two indicators of a clade’s success are its diversity (number of included species) and its disparity (extent of morphospace occupied by its members). Many large genera show high diversity with low disparity, while others such as Euphorbia and Drosophila are highly diverse but also exhibit high disparity. The largest genera are often characterized by key innovations that often, but not necessarily, coincide with their diagnostic apomorphies. In terms of their contribution to speciation, apomorphies are either permissive (e.g. flightlessness) or generative (e.g. nectariferous spurs). Scope Except for Drosophila, virtually no genus among those with the highest diversity or disparity includes species currently studied as model species in developmental genetics or evolutionary developmental biology (evo-devo). An evo-devo approach is, however, potentially important to understand how diversity and disparity could rapidly increase in the largest genera currently accepted by taxonomists. The most promising directions for future research and a set of key questions to be addressed are presented in this review. Conclusions From an evo-devo perspective, the evolution of clades with high diversity and/or disparity can be addressed from three main perspectives: (1) evolvability, in terms of release from previous constraints and of the presence of genetic or developmental conditions favouring multiple parallel occurrences of a given evolutionary transition and its reversal; (2) phenotypic plasticity as a facilitator of speciation; and (3) modularity, heterochrony and a coupling between the complexity of the life cycle and the evolution of diversity and disparity in a clade. This simple preliminary analysis suggests a set of topics that deserve priority for scrutiny, including the possible role of saltational evolution in the origination of high diversity and/or disparity, the predictability of morphological evolution following release from a former constraint, and the extent and the possible causes of a positive correlation between diversity and disparity and the complexity of the life cycle. PMID:26346718

Myxococcus xanthus Growth, Development, and Isolation.

PubMed

Vaksman, Zalman; Kaplan, Heidi B

2015-11-03

Myxobacteria are a highly social group among the delta proteobacteria that display unique multicellular behaviors during their complex life cycle and provide a rare opportunity to study the boundary between single cells and multicellularity. These organisms are also unusual as their entire life cycle is surface associated and includes a number of social behaviors: social gliding and rippling motility, 'wolf-pack'-like predation, and self-organizing complex biostructures, termed fruiting bodies, which are filled with differentiated environmentally resistant spores. Here we present methods for the growth, maintenance, and storage of Myxococcus xanthus, the most commonly studied of the myxobacteria. We also include methods to examine various developmental and social behaviors (fruiting body and spore formation, predation, and rippling motility). As the myxobacteria, similar to the streptomycetes, are excellent sources of many characterized and uncharacterized antibiotics and other natural products, we have provided a protocol for obtaining natural isolates from a variety of environmental sources. Copyright © 2015 John Wiley & Sons, Inc.

Genome-wide expression profiling of in vivo-derived bloodstream parasite stages and dynamic analysis of mRNA alterations during synchronous differentiation in Trypanosoma brucei

PubMed Central

Kabani, Sarah; Fenn, Katelyn; Ross, Alan; Ivens, Al; Smith, Terry K; Ghazal, Peter; Matthews, Keith

2009-01-01

Background Trypanosomes undergo extensive developmental changes during their complex life cycle. Crucial among these is the transition between slender and stumpy bloodstream forms and, thereafter, the differentiation from stumpy to tsetse-midgut procyclic forms. These developmental events are highly regulated, temporally reproducible and accompanied by expression changes mediated almost exclusively at the post-transcriptional level. Results In this study we have examined, by whole-genome microarray analysis, the mRNA abundance of genes in slender and stumpy forms of T.brucei AnTat1.1 cells, and also during their synchronous differentiation to procyclic forms. In total, five biological replicates representing the differentiation of matched parasite populations derived from five individual mouse infections were assayed, with RNAs being derived at key biological time points during the time course of their synchronous differentiation to procyclic forms. Importantly, the biological context of these mRNA profiles was established by assaying the coincident cellular events in each population (surface antigen exchange, morphological restructuring, cell cycle re-entry), thereby linking the observed gene expression changes to the well-established framework of trypanosome differentiation. Conclusion Using stringent statistical analysis and validation of the derived profiles against experimentally-predicted gene expression and phenotypic changes, we have established the profile of regulated gene expression during these important life-cycle transitions. The highly synchronous nature of differentiation between stumpy and procyclic forms also means that these studies of mRNA profiles are directly relevant to the changes in mRNA abundance within individual cells during this well-characterised developmental transition. PMID:19747379

The very-long-chain hydroxy fatty acyl-CoA dehydratase PASTICCINO2 is essential and limiting for plant development

PubMed Central

Bach, Liên; Michaelson, Louise V.; Haslam, Richard; Bellec, Yannick; Gissot, Lionel; Marion, Jessica; Da Costa, Marco; Boutin, Jean-Pierre; Miquel, Martine; Tellier, Frédérique; Domergue, Frederic; Markham, Jonathan E.; Beaudoin, Frederic; Napier, Johnathan A.; Faure, Jean-Denis

2008-01-01

Very-long-chain fatty acids (VLCFAs) are synthesized as acyl-CoAs by the endoplasmic reticulum-localized elongase multiprotein complex. Two Arabidopsis genes are putative homologues of the recently identified yeast 3-hydroxy-acyl-CoA dehydratase (PHS1), the third enzyme of the elongase complex. We showed that Arabidopsis PASTICCINO2 (PAS2) was able to restore phs1 cytokinesis defects and sphingolipid long chain base overaccumulation. Conversely, the expression of PHS1 was able to complement the developmental defects and the accumulation of long chain bases of the pas2–1 mutant. The pas2–1 mutant was characterized by a general reduction of VLCFA pools in seed storage triacylglycerols, cuticular waxes, and complex sphingolipids. Most strikingly, the defective elongation cycle resulted in the accumulation of 3-hydroxy-acyl-CoA intermediates, indicating premature termination of fatty acid elongation and confirming the role of PAS2 in this process. We demonstrated by in vivo bimolecular fluorescence complementation that PAS2 was specifically associated in the endoplasmic reticulum with the enoyl-CoA reductase CER10, the fourth enzyme of the elongase complex. Finally, complete loss of PAS2 function is embryo lethal, and the ectopic expression of PHS1 led to enhanced levels of VLCFAs associated with severe developmental defects. Altogether these results demonstrate that the plant 3-hydroxy-acyl-CoA dehydratase PASTICCINO2 is an essential and limiting enzyme in VLCFA synthesis but also that PAS2-derived VLCFA homeostasis is required for specific developmental processes. PMID:18799749

Cell and plastid division are coordinated through the prereplication factor AtCDT1

PubMed Central

Raynaud, Cécile; Perennes, Claudette; Reuzeau, Christophe; Catrice, Olivier; Brown, Spencer; Bergounioux, Catherine

2005-01-01

The cell division cycle involves nuclear and cytoplasmic events, namely organelle multiplication and distribution between the daughter cells. Until now, plastid and plant cell division have been considered as independent processes because they can be uncoupled. Here, down-regulation of AtCDT1a and AtCDT1b, members of the prereplication complex, is shown to alter both nuclear DNA replication and plastid division in Arabidopsis thaliana. These data constitute molecular evidence for relationships between the cell-cycle and plastid division. Moreover, the severe developmental defects observed in AtCDT1-RNA interference (RNAi) plants underline the importance of coordinated cell and organelle division for plant growth and morphogenesis. PMID:15928083

Tissue-Specific Control of the Endocycle by the Anaphase Promoting Complex/Cyclosome Inhibitors UVI4 and DEL1.

PubMed

Heyman, Jefri; Polyn, Stefanie; Eekhout, Thomas; De Veylder, Lieven

2017-09-01

The endocycle represents a modified mitotic cell cycle that in plants is often coupled to cell enlargement and differentiation. Endocycle onset is controlled by activity of the Anaphase Promoting Complex/Cyclosome (APC/C), a multisubunit E3 ubiquitin ligase targeting cell-cycle factors for destruction. CELL CYCLE SWITCH52 (CCS52) proteins represent rate-limiting activator subunits of the APC/C. In Arabidopsis ( Arabidopsis thaliana ), mutations in either CCS52A1 or CCS52A2 activators result in a delayed endocycle onset, whereas their overexpression triggers increased DNA ploidy levels. Here, the relative contribution of the APC/C CCS52A1 and APC/C CCS52A2 complexes to different developmental processes was studied through analysis of their negative regulators, being the ULTRAVIOLET-B-INSENSITIVE4 protein and the DP-E2F-Like1 transcriptional repressor, respectively. Our data illustrate cooperative activity of the APC/C CCS52A1 and APC/C CCS52A2 complexes during root and trichome development, but functional interdependency during leaf development. Furthermore, we found APC/C CCS52A1 activity to control CCS52A2 expression. We conclude that interdependency of CCS52A-controlled APC/C activity is controlled in a tissue-specific manner. © 2017 American Society of Plant Biologists. All Rights Reserved.

Computational Modeling and Simulation of Developmental ...

EPA Pesticide Factsheets

Developmental and Reproductive Toxicity (DART) testing is important for assessing the potential consequences of drug and chemical exposure on human health and well-being. Complexity of pregnancy and the reproductive cycle makes DART testing challenging and costly for traditional (animal-based) methods. A compendium of in vitro data from ToxCast/Tox21 high-throughput screening (HTS) programs is available for predictive toxicology. ‘Predictive DART’ will require an integrative strategy that mobilizes HTS data into in silico models that capture the relevant embryology. This lecture addresses progress on EPA's 'virtual embryo'. The question of how tissues and organs are shaped during development is crucial for understanding (and predicting) human birth defects. While ToxCast HTS data may predict developmental toxicity with reasonable accuracy, mechanistic models are still necessary to capture the relevant biology. Subtle microscopic changes induced chemically may amplify to an adverse outcome but coarse changes may override lesion propagation in any complex adaptive system. Modeling system dynamics in a developing tissue is a multiscale problem that challenges our ability to predict toxicity from in vitro profiling data (ToxCast/Tox21). (DISCLAIMER: The views expressed in this presentation are those of the presenter and do not necessarily reflect the views or policies of the US EPA). This was an invited seminar presentation to the National Institute for Public H

Quantitative Proteomics Analysis of Streptomyces coelicolor Development Demonstrates That Onset of Secondary Metabolism Coincides with Hypha Differentiation*

PubMed Central

Manteca, Angel; Sanchez, Jesus; Jung, Hye R.; Schwämmle, Veit; Jensen, Ole N.

2010-01-01

Streptomyces species produce many clinically important secondary metabolites, including antibiotics and antitumorals. They have a complex developmental cycle, including programmed cell death phenomena, that makes this bacterium a multicellular prokaryotic model. There are two differentiated mycelial stages: an early compartmentalized vegetative mycelium (first mycelium) and a multinucleated reproductive mycelium (second mycelium) arising after programmed cell death processes. In the present study, we made a detailed proteomics analysis of the distinct developmental stages of solid confluent Streptomyces coelicolor cultures using iTRAQ (isobaric tags for relative and absolute quantitation) labeling and LC-MS/MS. A new experimental approach was developed to obtain homogeneous samples at each developmental stage (temporal protein analysis) and also to obtain membrane and cytosolic protein fractions (spatial protein analysis). A total of 345 proteins were quantified in two biological replicates. Comparative bioinformatics analyses revealed the switch from primary to secondary metabolism between the initial compartmentalized mycelium and the multinucleated hyphae. PMID:20224110

The SnSAG merozoite surface antigens of Sarcocystis neurona are expressed differentially during the bradyzoite and sporozoite life cycle stages.

PubMed

Gautam, A; Dubey, J P; Saville, W J; Howe, D K

2011-12-29

Sarcocystis neurona is a two-host coccidian parasite whose complex life cycle progresses through multiple developmental stages differing at morphological and molecular levels. The S. neurona merozoite surface is covered by multiple, related glycosylphosphatidylinositol-linked proteins, which are orthologous to the surface antigen (SAG)/SAG1-related sequence (SRS) gene family of Toxoplasma gondii. Expression of the SAG/SRS proteins in T. gondii and another related parasite Neospora caninum is life-cycle stage specific and seems necessary for parasite transmission and persistence of infection. In the present study, the expression of S. neurona merozoite surface antigens (SnSAGs) was evaluated in the sporozoite and bradyzoite stages. Western blot analysis was used to compare SnSAG expression in merozoites versus sporozoites, while immunocytochemistry was performed to examine expression of the SnSAGs in merozoites versus bradyzoites. These analyses revealed that SnSAG2, SnSAG3 and SnSAG4 are expressed in sporozoites, while SnSAG5 was appeared to be downregulated in this life cycle stage. In S. neurona bradyzoites, it was found that SnSAG2, SnSAG3, SnSAG4 and SnSAG5 were either absent or expression was greatly reduced. As shown for T. gondii, stage-specific expression of the SnSAGs may be important for the parasite to progress through its developmental stages and complete its life cycle successfully. Thus, it is possible that the SAG switching mechanism by these parasites could be exploited as a point of intervention. As well, the alterations in surface antigen expression during different life cycle stages may need to be considered when designing prospective approaches for protective vaccination. Copyright © 2011 Elsevier B.V. All rights reserved.

Pre-sporulation stages of Streptomyces differentiation: state-of-the-art and future perspectives

PubMed Central

Yagüe, Paula; López-García, Maria T.; Rioseras, Beatriz; Sánchez, Jesús; Manteca, Ángel

2013-01-01

Streptomycetes comprise very important industrial bacteria, producing two-thirds of all clinically relevant secondary metabolites. They are mycelial microorganisms with complex developmental cycles that include programmed cell death (PCD) and sporulation. Industrial fermentations are usually performed in liquid cultures (large bioreactors), conditions in which Streptomyces strains generally do not sporulate, and it was traditionally assumed that there was no differentiation. In this work, we review the current knowledge on Streptomyces pre-sporulation stages of Streptomyces differentiation. PMID:23496097

Progranulin regulates neurogenesis in the developing vertebrate retina.

PubMed

Walsh, Caroline E; Hitchcock, Peter F

2017-09-01

We evaluated the expression and function of the microglia-specific growth factor, Progranulin-a (Pgrn-a) during developmental neurogenesis in the embryonic retina of zebrafish. At 24 hpf pgrn-a is expressed throughout the forebrain, but by 48 hpf pgrn-a is exclusively expressed by microglia and/or microglial precursors within the brain and retina. Knockdown of Pgrn-a does not alter the onset of neurogenic programs or increase cell death, however, in its absence, neurogenesis is significantly delayed-retinal progenitors fail to exit the cell cycle at the appropriate developmental time and postmitotic cells do not acquire markers of terminal differentiation, and microglial precursors do not colonize the retina. Given the link between Progranulin and cell cycle regulation in peripheral tissues and transformed cells, we analyzed cell cycle kinetics among retinal progenitors following Pgrn-a knockdown. Depleting Pgrn-a results in a significant lengthening of the cell cycle. These data suggest that Pgrn-a plays a dual role during nervous system development by governing the rate at which progenitors progress through the cell cycle and attracting microglial progenitors into the embryonic brain and retina. Collectively, these data show that Pgrn-a governs neurogenesis by regulating cell cycle kinetics and the transition from proliferation to cell cycle exit and differentiation. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol 77: 1114-1129, 2017. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc.

OF TRYPANOSOMATIDS. ENDOTRANSFORMATIONS AND ABERRATIONS].

PubMed

Frolov, A O; Malysheva, M N; Kostygov, A Yu

2016-01-01

Endotransformations and aberrations of the life cycle in the evolutionary history of trypanosomatids (Kinetoplastea: Trypanosomatidae) are analyzed. We treat the term "endotransformations" as evolutionarily fixed changes of phases and/or developmental stages of parasites. By contrast, we treat aberrations as evolutionary unstable, periodically arising deformations of developmental phases of trypanosomatids, never leading to life cycle changes. Various examples of life cycle endotransformations and aberrations in representatives of the family Trypanosomatidae are discussed.

Quantitative imaging with Fucci and mathematics to uncover temporal dynamics of cell cycle progression.

PubMed

Saitou, Takashi; Imamura, Takeshi

2016-01-01

Cell cycle progression is strictly coordinated to ensure proper tissue growth, development, and regeneration of multicellular organisms. Spatiotemporal visualization of cell cycle phases directly helps us to obtain a deeper understanding of controlled, multicellular, cell cycle progression. The fluorescent ubiquitination-based cell cycle indicator (Fucci) system allows us to monitor, in living cells, the G1 and the S/G2/M phases of the cell cycle in red and green fluorescent colors, respectively. Since the discovery of Fucci technology, it has found numerous applications in the characterization of the timing of cell cycle phase transitions under diverse conditions and various biological processes. However, due to the complexity of cell cycle dynamics, understanding of specific patterns of cell cycle progression is still far from complete. In order to tackle this issue, quantitative approaches combined with mathematical modeling seem to be essential. Here, we review several studies that attempted to integrate Fucci technology and mathematical models to obtain quantitative information regarding cell cycle regulatory patterns. Focusing on the technological development of utilizing mathematics to retrieve meaningful information from the Fucci producing data, we discuss how the combined methods advance a quantitative understanding of cell cycle regulation. © 2015 Japanese Society of Developmental Biologists.

Postural complexity influences development in infants born preterm with brain injury: relating perception-action theory to 3 cases.

PubMed

Dusing, Stacey C; Izzo, Theresa; Thacker, Leroy R; Galloway, James Cole

2014-10-01

Perception-action theory suggests a cyclical relationship between movement and perceptual information. In this case series, changes in postural complexity were used to quantify an infant's action and perception during the development of early motor behaviors. Three infants born preterm with periventricular white matter injury were included. Longitudinal changes in postural complexity (approximate entropy of the center of pressure), head control, reaching, and global development, measured with the Test of Infant Motor Performance and the Bayley Scales of Infant and Toddler Development, were assessed every 0.5 to 3 months during the first year of life. All 3 infants demonstrated altered postural complexity and developmental delays. However, the timing of the altered postural complexity and the type of delays varied among the infants. For infant 1, reduced postural complexity or limited action while learning to control her head in the midline position may have contributed to her motor delay. However, her ability to adapt her postural complexity eventually may have supported her ability to learn from her environment, as reflected in her relative cognitive strength. For infant 2, limited early postural complexity may have negatively affected his learning through action, resulting in cognitive delay. For infant 3, an increase in postural complexity above typical levels was associated with declining neurological status. Postural complexity is proposed as a measure of perception and action in the postural control system during the development of early behaviors. An optimal, intermediate level of postural complexity supports the use of a variety of postural control strategies and enhances the perception-action cycle. Either excessive or reduced postural complexity may contribute to developmental delays in infants born preterm with white matter injury. © 2014 American Physical Therapy Association.

Species diversity vs. morphological disparity in the light of evolutionary developmental biology.

PubMed

Minelli, Alessandro

2016-04-01

Two indicators of a clade's success are its diversity (number of included species) and its disparity (extent of morphospace occupied by its members). Many large genera show high diversity with low disparity, while others such as Euphorbia and Drosophila are highly diverse but also exhibit high disparity. The largest genera are often characterized by key innovations that often, but not necessarily, coincide with their diagnostic apomorphies. In terms of their contribution to speciation, apomorphies are either permissive (e.g. flightlessness) or generative (e.g. nectariferous spurs). Except for Drosophila, virtually no genus among those with the highest diversity or disparity includes species currently studied as model species in developmental genetics or evolutionary developmental biology (evo-devo). An evo-devo approach is, however, potentially important to understand how diversity and disparity could rapidly increase in the largest genera currently accepted by taxonomists. The most promising directions for future research and a set of key questions to be addressed are presented in this review. From an evo-devo perspective, the evolution of clades with high diversity and/or disparity can be addressed from three main perspectives: (1) evolvability, in terms of release from previous constraints and of the presence of genetic or developmental conditions favouring multiple parallel occurrences of a given evolutionary transition and its reversal; (2) phenotypic plasticity as a facilitator of speciation; and (3) modularity, heterochrony and a coupling between the complexity of the life cycle and the evolution of diversity and disparity in a clade. This simple preliminary analysis suggests a set of topics that deserve priority for scrutiny, including the possible role of saltational evolution in the origination of high diversity and/or disparity, the predictability of morphological evolution following release from a former constraint, and the extent and the possible causes of a positive correlation between diversity and disparity and the complexity of the life cycle. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Complexes of D-type cyclins with CDKs during maize germination

PubMed Central

Vázquez-Ramos, Jorge M.

2013-01-01

The importance of cell proliferation in plant growth and development has been well documented. The majority of studies on basic cell cycle mechanisms in plants have been at the level of gene expression and much less knowledge has accumulated in terms of protein interactions and activation. Two key proteins, cyclins and cyclin-dependent kinases (CDKs) are fundamental for cell cycle regulation and advancement. Our aim has been to understand the role of D-type cyclins and type A and B CDKs in the cell cycle taking place during a developmental process such as maize seed germination. Results indicate that three maize D-type cyclins—D2;2, D4;2, and D5;3—(G1-S cyclins by definition) bind and activate two different types of CDK—A and B1;1—in a differential way during germination. Whereas CDKA–D-type cyclin complexes are more active at early germination times than at later times, it was surprising to observe that CDKB1;1, a supposedly G2-M kinase, bound in a differential way to all D-type cyclins tested during germination. Binding to cyclin D2;2 was detectable at all germination times, forming a complex with kinase activity, whereas binding to D4;2 and D5;3 was more variable; in particular, D5;3 was only detected at late germination times. Results are discussed in terms of cell cycle advancement and its importance for seed germination. PMID:24127516

Polymorphism of Malassezia furfur.

PubMed

Salkin, I F; Gordon, M A

1977-04-01

Alterations in the morphologic and physiologic characters of 11 isolates of Pityrosporum orbiculare were noted upon prolonged maintenance in pure culture. Successive subculturing of each isolate resulted in its progressive conversion from globose (P. orbiculare) through ovoid to cylindrical (P. ovale) form. Globose forms utilized neither olive oil nor Tween 20 as a sole carbon source, nor KNO3 as a sole source of nitrogen, while ovoid and cylindrical forms utilized both of these carbon sources, and one of four strains of the cylindrical form assimilated KNO3. These results suggest that P. orbiculare and P. ovale are stages in the complex developmental cycle of a single species (Malassezia furfur), but the three names should be preserved until the life cycle is more fully understood.

Recurrent sublethal warming reduces embryonic survival, inhibits juvenile growth, and alters species distribution projections under climate change.

PubMed

Carlo, Michael A; Riddell, Eric A; Levy, Ofir; Sears, Michael W

2018-01-01

The capacity to tolerate climate change often varies across ontogeny in organisms with complex life cycles. Recently developed species distribution models incorporate traits across life stages; however, these life-cycle models primarily evaluate effects of lethal change. Here, we examine impacts of recurrent sublethal warming on development and survival in ecological projections of climate change. We reared lizard embryos in the laboratory under temperature cycles that simulated contemporary conditions and warming scenarios. We also artificially warmed natural nests to mimic laboratory treatments. In both cases, recurrent sublethal warming decreased embryonic survival and hatchling sizes. Incorporating survivorship results into a mechanistic species distribution model reduced annual survival by up to 24% compared to models that did not incorporate sublethal warming. Contrary to models without sublethal effects, our model suggests that modest increases in developmental temperatures influence species ranges due to effects on survivorship. © 2017 John Wiley & Sons Ltd/CNRS.

The Developmental Cycle: Teachings on the Eight Stages of Growth of a Human Being.

ERIC Educational Resources Information Center

Coyhis, Don

1997-01-01

Ties Native American Medicine Wheel teachings on the cycle of life to Eric Erickson's work on the eight developmental stages: trust, autonomy, initiative, accomplishment, identity, intimacy, generativity, and integrity. To have healthy communities, people need to move successfully through these stages. Knowing about these stages can help a person…

Ontogenetic optimal temperature and salinity envelops of the copepod Eurytemora affinis in the Seine estuary (France)

NASA Astrophysics Data System (ADS)

Dur, Gaël; Souissi, Sami

2018-01-01

Temperature and salinity are important factors shaping the habitats of estuarine ectotherms. Their respective effect varies along the life history moments of species with a complex life cycle. Estuarine species, particularly those living in the salinity gradient, are concerned by habitat changes that can reduce their fitness. Consequently, efforts to define the importance of those two environmental variables on developmental stages are required to enable forecasting estuarine species' future distributions. The present study focuses on the main component of the Seine estuary's zooplankton, i.e. the calanoid copepod Eurytemora affinis, and aims: (i) to establish the role of temperature and salinity in designing the habitat of E. affinis within the Seine estuary; and (ii) to model the habitat of three groups of E. affinis defined through the life cycle as follows: all larval instars (N1-N6), the first to fourth juvenile instars (C1-C4), and the pre-adult and adults instars (C5-Adults). For this purpose, data from intensive field studies of zooplankton sampling during 2002-2010 were used. The fine-scale data, i.e., every 10-20 min, on density and abiotic conditions (salinity, temperature) provided inputs for the computation. We established regions in salinity-temperature space where the three groups of developmental instars exhibit higher densities. The computed habitats differ between developmental groups. In general, the preferendum of salinity increases with ontogeny. The optima of temperature are rather constant between developmental stages (∼14 °C). Our model can be used to determine E. affinis functional habitat (i.e., the spatial relation with structuring factors), to carry out retrospective analysis, and to test future distributions. The present study also emphasizes the need of data from appropriate sampling strategies to conduct habitat definition.

The Transcription Factor Rbf1 Is the Master Regulator for b-Mating Type Controlled Pathogenic Development in Ustilago maydis

PubMed Central

Vranes, Miroslav; Wahl, Ramon; Pothiratana, Chetsada; Schuler, David; Vincon, Volker; Finkernagel, Florian; Flor-Parra, Ignacio; Kämper, Jörg

2010-01-01

In the phytopathogenic basidiomycete Ustilago maydis, sexual and pathogenic development are tightly connected and controlled by the heterodimeric bE/bW transcription factor complex encoded by the b-mating type locus. The formation of the active bE/bW heterodimer leads to the formation of filaments, induces a G2 cell cycle arrest, and triggers pathogenicity. Here, we identify a set of 345 bE/bW responsive genes which show altered expression during these developmental changes; several of these genes are associated with cell cycle coordination, morphogenesis and pathogenicity. 90% of the genes that show altered expression upon bE/bW-activation require the zinc finger transcription factor Rbf1, one of the few factors directly regulated by the bE/bW heterodimer. Rbf1 is a novel master regulator in a multilayered network of transcription factors that facilitates the complex regulatory traits of sexual and pathogenic development. PMID:20700446

Dual Functions of α-Ketoglutarate Dehydrogenase E2 in the Krebs Cycle and Mitochondrial DNA Inheritance in Trypanosoma brucei

PubMed Central

Sykes, Steven E.

2013-01-01

The dihydrolipoyl succinyltransferase (E2) of the multisubunit α-ketoglutarate dehydrogenase complex (α-KD) is an essential Krebs cycle enzyme commonly found in the matrices of mitochondria. African trypanosomes developmentally regulate mitochondrial carbohydrate metabolism and lack a functional Krebs cycle in the bloodstream of mammals. We found that despite the absence of a functional α-KD, bloodstream form (BF) trypanosomes express α-KDE2, which localized to the mitochondrial matrix and inner membrane. Furthermore, α-KDE2 fractionated with the mitochondrial genome, the kinetoplast DNA (kDNA), in a complex with the flagellum. A role for α-KDE2 in kDNA maintenance was revealed in α-KDE2 RNA interference (RNAi) knockdowns. Following RNAi induction, bloodstream trypanosomes showed pronounced growth reduction and often failed to equally distribute kDNA to daughter cells, resulting in accumulation of cells devoid of kDNA (dyskinetoplastic) or containing two kinetoplasts. Dyskinetoplastic trypanosomes lacked mitochondrial membrane potential and contained mitochondria of substantially reduced volume. These results indicate that α-KDE2 is bifunctional, both as a metabolic enzyme and as a mitochondrial inheritance factor necessary for the distribution of kDNA networks to daughter cells at cytokinesis. PMID:23125353

Dual functions of α-ketoglutarate dehydrogenase E2 in the Krebs cycle and mitochondrial DNA inheritance in Trypanosoma brucei.

PubMed

Sykes, Steven E; Hajduk, Stephen L

2013-01-01

The dihydrolipoyl succinyltransferase (E2) of the multisubunit α-ketoglutarate dehydrogenase complex (α-KD) is an essential Krebs cycle enzyme commonly found in the matrices of mitochondria. African trypanosomes developmentally regulate mitochondrial carbohydrate metabolism and lack a functional Krebs cycle in the bloodstream of mammals. We found that despite the absence of a functional α-KD, bloodstream form (BF) trypanosomes express α-KDE2, which localized to the mitochondrial matrix and inner membrane. Furthermore, α-KDE2 fractionated with the mitochondrial genome, the kinetoplast DNA (kDNA), in a complex with the flagellum. A role for α-KDE2 in kDNA maintenance was revealed in α-KDE2 RNA interference (RNAi) knockdowns. Following RNAi induction, bloodstream trypanosomes showed pronounced growth reduction and often failed to equally distribute kDNA to daughter cells, resulting in accumulation of cells devoid of kDNA (dyskinetoplastic) or containing two kinetoplasts. Dyskinetoplastic trypanosomes lacked mitochondrial membrane potential and contained mitochondria of substantially reduced volume. These results indicate that α-KDE2 is bifunctional, both as a metabolic enzyme and as a mitochondrial inheritance factor necessary for the distribution of kDNA networks to daughter cells at cytokinesis.

Modeling metabolism and stage-specific growth of Plasmodium falciparum HB3 during the intraerythrocytic developmental cycle.

PubMed

Fang, Xin; Reifman, Jaques; Wallqvist, Anders

2014-10-01

The human malaria parasite Plasmodium falciparum goes through a complex life cycle, including a roughly 48-hour-long intraerythrocytic developmental cycle (IDC) in human red blood cells. A better understanding of the metabolic processes required during the asexual blood-stage reproduction will enhance our basic knowledge of P. falciparum and help identify critical metabolic reactions and pathways associated with blood-stage malaria. We developed a metabolic network model that mechanistically links time-dependent gene expression, metabolism, and stage-specific growth, allowing us to predict the metabolic fluxes, the biomass production rates, and the timing of production of the different biomass components during the IDC. We predicted time- and stage-specific production of precursors and macromolecules for P. falciparum (strain HB3), allowing us to link specific metabolites to specific physiological functions. For example, we hypothesized that coenzyme A might be involved in late-IDC DNA replication and cell division. Moreover, the predicted ATP metabolism indicated that energy was mainly produced from glycolysis and utilized for non-metabolic processes. Finally, we used the model to classify the entire tricarboxylic acid cycle into segments, each with a distinct function, such as superoxide detoxification, glutamate/glutamine processing, and metabolism of fumarate as a byproduct of purine biosynthesis. By capturing the normal metabolic and growth progression in P. falciparum during the IDC, our model provides a starting point for further elucidation of strain-specific metabolic activity, host-parasite interactions, stress-induced metabolic responses, and metabolic responses to antimalarial drugs and drug candidates.

Epigenetics and the Developmental Origins of Health and ...

EPA Pesticide Factsheets

Epigenetic programming is likely to be an important mechanism underlying the lasting influence of the developmental environment on lifelong health, a concept known as the Developmental Origins of Health and Disease (DOHaD). DNA methylation, posttranslational histone protei n modifications, noncoding RNAs and recruited protein complexes are elements of the epigenetic regulation of gene transcription. These heritable but reversible changes in gene function are dynamic and labile during specific stages of the reproductive cycle and development. Epigenetic marks may be maintained throughout an individual's lifespan and can alter the life-long risk of disease; the nature of these epigenetic marks and their potential alteration by environmental factors is an area of active research. This chapter provides an overview of epigenetic regulation, particularly as it occurs as an essential component of embryo-fetal development. In this chapter we will present key features of DNA methylation and histone protein modifications, including the enzymes involved and the effects of these modifications on gene transcription. We will discuss the interplay of these dynamic modifications and the emerging role of noncoding RNAs in epigenetic gene regulation.

Emergence of polycystic neotropical echinococcosis.

PubMed

Tappe, Dennis; Stich, August; Frosch, Matthias

2008-02-01

Echinococcosis is a parasitic zoonosis of increasing concern. In 1903, the first cases of human polycystic echinococcosis, a disease resembling alveolar echinococcosis, emerged in Argentina. One of the parasites responsible, Echinococcus oligarthrus, had been discovered in its adult strobilar stage before 1850. However, >100 years passed from the first description of the adult parasite to the recognition that this species is responsible for some cases of human neotropical polycystic echinococcosis and the elucidation of the parasite's life cycle. A second South American species, E. vogeli, was described in 1972. Obtaining recognition of the 2 species and establishing their connection to human disease were complicated because the life cycle of tapeworms is complex and comprises different developmental stages in diverse host species. To date, at least 106 human cases have been reported from 12 South and Central American countries.

A Developmental Learning Approach of Mobile Manipulator via Playing

PubMed Central

Wu, Ruiqi; Zhou, Changle; Chao, Fei; Zhu, Zuyuan; Lin, Chih-Min; Yang, Longzhi

2017-01-01

Inspired by infant development theories, a robotic developmental model combined with game elements is proposed in this paper. This model does not require the definition of specific developmental goals for the robot, but the developmental goals are implied in the goals of a series of game tasks. The games are characterized into a sequence of game modes based on the complexity of the game tasks from simple to complex, and the task complexity is determined by the applications of developmental constraints. Given a current mode, the robot switches to play in a more complicated game mode when it cannot find any new salient stimuli in the current mode. By doing so, the robot gradually achieves it developmental goals by playing different modes of games. In the experiment, the game was instantiated into a mobile robot with the playing task of picking up toys, and the game is designed with a simple game mode and a complex game mode. A developmental algorithm, “Lift-Constraint, Act and Saturate,” is employed to drive the mobile robot move from the simple mode to the complex one. The experimental results show that the mobile manipulator is able to successfully learn the mobile grasping ability after playing simple and complex games, which is promising in developing robotic abilities to solve complex tasks using games. PMID:29046632

Evidence of a conserved role for Chlamydia HtrA in the replication phase of the chlamydial developmental cycle.

PubMed

Patel, Pooja; De Boer, Leonore; Timms, Peter; Huston, Wilhelmina May

2014-08-01

Identification of the HtrA inhibitor JO146 previously enabled us to demonstrate an essential function for HtrA during the mid-replicative phase of the Chlamydia trachomatis developmental cycle. Here we extend our investigations to other members of the Chlamydia genus. C. trachomatis isolates with distinct replicative phase growth kinetics showed significant loss of viable infectious progeny after HtrA was inhibited during the replicative phase. Mid-replicative phase addition of JO146 was also significantly detrimental to Chlamydia pecorum, Chlamydia suis and Chlamydia cavie. These data combined indicate that HtrA has a conserved critical role during the replicative phase of the chlamydial developmental cycle. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Discovery of time-delayed gene regulatory networks based on temporal gene expression profiling

PubMed Central

Li, Xia; Rao, Shaoqi; Jiang, Wei; Li, Chuanxing; Xiao, Yun; Guo, Zheng; Zhang, Qingpu; Wang, Lihong; Du, Lei; Li, Jing; Li, Li; Zhang, Tianwen; Wang, Qing K

2006-01-01

Background It is one of the ultimate goals for modern biological research to fully elucidate the intricate interplays and the regulations of the molecular determinants that propel and characterize the progression of versatile life phenomena, to name a few, cell cycling, developmental biology, aging, and the progressive and recurrent pathogenesis of complex diseases. The vast amount of large-scale and genome-wide time-resolved data is becoming increasing available, which provides the golden opportunity to unravel the challenging reverse-engineering problem of time-delayed gene regulatory networks. Results In particular, this methodological paper aims to reconstruct regulatory networks from temporal gene expression data by using delayed correlations between genes, i.e., pairwise overlaps of expression levels shifted in time relative each other. We have thus developed a novel model-free computational toolbox termed TdGRN (Time-delayed Gene Regulatory Network) to address the underlying regulations of genes that can span any unit(s) of time intervals. This bioinformatics toolbox has provided a unified approach to uncovering time trends of gene regulations through decision analysis of the newly designed time-delayed gene expression matrix. We have applied the proposed method to yeast cell cycling and human HeLa cell cycling and have discovered most of the underlying time-delayed regulations that are supported by multiple lines of experimental evidence and that are remarkably consistent with the current knowledge on phase characteristics for the cell cyclings. Conclusion We established a usable and powerful model-free approach to dissecting high-order dynamic trends of gene-gene interactions. We have carefully validated the proposed algorithm by applying it to two publicly available cell cycling datasets. In addition to uncovering the time trends of gene regulations for cell cycling, this unified approach can also be used to study the complex gene regulations related to the development, aging and progressive pathogenesis of a complex disease where potential dependences between different experiment units might occurs. PMID:16420705

Developmental Care Rounds: An Interdisciplinary Approach to Support Developmentally Appropriate Care of Infants Born with Complex Congenital Heart Disease.

PubMed

Lisanti, Amy Jo; Cribben, Jeanne; Connock, Erin McManus; Lessen, Rachelle; Medoff-Cooper, Barbara

2016-03-01

Newborn infants with complex congenital heart disease are at risk for developmental delay. Developmental care practices benefit prematurely born infants in neonatal intensive care units. Cardiac intensive care units until recently had not integrated developmental care practices into their care framework. Interdisciplinary developmental care rounds in our center have helped in the promotion of developmentally supportive care for infants before and after cardiac surgery. This article discusses basic principles of developmental care, the role of each member of the interdisciplinary team on rounds, common developmental care practices integrated into care from rounds, and impacts to patients, families, and staff. Copyright © 2016 Elsevier Inc. All rights reserved.

Predicting developmental neurotoxicity in rodents from larval zebrafish - - and vice versa

EPA Science Inventory

The complexity of standard mammalian developmental neurotoxicity tests limits evaluation of large numbers of chemicals. Less complex, more rapid assays using larval zebrafish are gaining popularity for evaluating the developmental neurotoxicity of chemicals; there remains, howeve...

Comparison of VO[subscript 2] Maximum Obtained from 20 m Shuttle Run and Cycle Ergometer in Children with and without Developmental Coordination Disorder

ERIC Educational Resources Information Center

Cairney, John; Hay, John; Veldhuizen, Scott; Faught, Brent

2010-01-01

Oxygen consumption at peak physical exertion (VO[subscript 2] maximum) is the most widely used indicator of cardiorespiratory fitness. The purpose of this study was to compare two protocols for its estimation, cycle ergometer testing and the 20 m shuttle run, among children with and without probable developmental coordination disorder (pDCD). The…

[Epigenetics, interface between environment and genes: role in complex diseases].

PubMed

Scheen, A J; Junien, C

2012-01-01

Epigenetics is the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence. Epigenetics is one of the major mechanisms explaining the "Developmental Origin of Health and Diseases" (DOHaD). Besides genetic background inherited from parents, which confers susceptibility to certain pathologies, epigenetic changes constitute the memory of previous events, either positive or negative, along the life cycle, including at the in utero stage. The later exposition to hostile environment may reveal such susceptibility, with the development of various pathologies, among them numerous chronic complex diseases. The demonstration of such a sequence of events has been shown for metabolic diseases as obesity, metabolic syndrome and type 2 diabetes, cardiovascular disease and cancer. In contrast to genetic predisposition, which is irreversible, epigenetic changes are potentially reversible, thus giving targets not only for prevention, but possibly also for the treatment of certain complex diseases.

Life-cycle and growth-phase-dependent regulation of the ubiquitin genes of Trypanosoma cruzi.

PubMed

Manning-Cela, Rebeca; Jaishankar, Sobha; Swindle, John

2006-07-01

Trypanosoma cruzi, the causative agent of Chagas disease, exhibits a complex life cycle that is accompanied by the stage-specific gene expression. At the molecular level, very little is known about gene regulation in trypanosomes. Complex gene organizations coupled with polycistronic transcription units make the analysis of regulated gene expression difficult in trypanosomes. The ubiquitin genes of T. cruzi are a good example of this complexity. They are organized as a single cluster containing five ubiquitin fusion (FUS) and five polyubiquitin (PUB) genes that are polycistronically transcribed but expressed differently in response to developmental and environmental changes. Gene replacements were used to study FUS and PUB gene expression at different stages of growth and at different points in the life cycle of T. cruzi. Based on the levels of reporter gene expression, it was determined that FUS1 expression was downregulated as the parasites approached stationary phase, whereas PUB12.5 polyubiquitin gene expression increased. Conversely, FUS1 expression increases when epimastigotes and amastigotes differentiate into trypomastigotes, whereas the expression of PUB12.5 decreases when epimastigotes differentiate into amastigotes and trypomastigotes. Although the level of CAT activity in logarithmic growing epimastigotes is six- to seven-fold higher when the gene was expressed from the FUS1 locus than when expressed from the PUB12.5 locus, the rate of transcription from the two loci was the same implying that post-transcriptional mechanisms play a dominant role in the regulation of gene expression.

Emergence of Polycystic Neotropical Echinococcosis

PubMed Central

Stich, August; Frosch, Matthias

2008-01-01

Echinococcosis is a parasitic zoonosis of increasing concern. In 1903, the first cases of human polycystic echinococcosis, a disease resembling alveolar echinococcosis, emerged in Argentina. One of the parasites responsible, Echinococcus oligarthrus, had been discovered in its adult strobilar stage before 1850. However, >100 years passed from the first description of the adult parasite to the recognition that this species is responsible for some cases of human neotropical polycystic echinococcosis and the elucidation of the parasite’s life cycle. A second South American species, E. vogeli, was described in 1972. Obtaining recognition of the 2 species and establishing their connection to human disease were complicated because the life cycle of tapeworms is complex and comprises different developmental stages in diverse host species. To date, at least 106 human cases have been reported from 12 South and Central American countries. PMID:18258123

Fructan metabolism in A. tequilana Weber Blue variety along its developmental cycle in the field.

PubMed

Mellado-Mojica, Erika; López, Mercedes G

2012-11-28

Fructan, as reserve carbohydrate, supplies energy needs during vegetative development, thereby exhibiting variations in its content and composition. Fructan metabolism in Agave tequilana Blue variety from 2- to 7-year-old plants was analyzed in this work. Soluble carbohydrates were determined at all ages. Fructan (328-711 mg/g), sucrose (14-39 mg/g), fructose (11-20 mg/g), glucose (4-14 mg/g), and starch (0.58-4.98 mg/g) were the most abundant carbohydrates. Thin-layer chromatography exhibited that 2-5-year-old plants mainly stored fructooligosaccharides, while 6-7-year-old plants mainly contained long-chain fructans. The fructan degree of polymerization (DP) increased from 6 to 23 throughout plant development. The 7-year-old plants mainly stored highly branched agavins. Partially methylated alditol acetate analyzed by gas chromatography-mass spectrometry reveals that fructan molecular structures became more complex with plant age. For the first time, we report the presence of a large number of DP3 (seven forms), DP4 (eight forms), and DP5 (six forms) isomers for agave fructans. Overall, fructan metabolism in A. tequilana displays changes in its soluble carbohydrates, DP, type, and fructan structures stored, along its developmental cycle in the field.

The molecular mechanisms of larval cestode development: first steps into an unknown world.

PubMed

Brehm, Klaus; Spiliotis, Markus; Zavala-Góngora, Ricardo; Konrad, Christian; Frosch, Matthias

2006-01-01

Several hundred million years ago, the free-living ancestors of all extant helminth parasites decided to colonize entirely new habitats, the bodies of other metazoan animals. As a consequence of the resulting adaptation processes, they evolved highly complex life-cycles in which many developmental transitions were initiated and controlled by host-derived signals. Understanding the molecular basis of the original developmental mechanisms, and the modifications that occurred during co-evolution with the host, is not only fundamental to our understanding of parasitism but also highly relevant for the design of anti-parasitic drugs and vaccines. In the past several years, molecular investigations on parasitic nematode and trematode development have made considerable progress and, supported by respective genome sequencing projects and emerging methods of genetic manipulation, will be a flourishing field in the years to come. We consider it time that corresponding studies are also pushed for the third large group of parasitic helminths, the cestodes. Here, we review the first experimental steps into that area, which have been undertaken recently. We report on cestode genomics, the identification of signaling factors associated with larval development, and the establishment as well as improvement of in vitro cultivation systems by which cestode life-cycles can be studied in the laboratory.

Factors affecting the development of somatic cell nuclear transfer embryos in Cattle.

PubMed

Akagi, Satoshi; Matsukawa, Kazutsugu; Takahashi, Seiya

2014-01-01

Nuclear transfer is a complex multistep procedure that includes oocyte maturation, cell cycle synchronization of donor cells, enucleation, cell fusion, oocyte activation and embryo culture. Therefore, many factors are believed to contribute to the success of embryo development following nuclear transfer. Numerous attempts to improve cloning efficiency have been conducted since the birth of the first sheep by somatic cell nuclear transfer. However, the efficiency of somatic cell cloning has remained low, and applications have been limited. In this review, we discuss some of the factors that affect the developmental ability of somatic cell nuclear transfer embryos in cattle.

Pre-sporulation stages of Streptomyces differentiation: state-of-the-art and future perspectives.

PubMed

Yagüe, Paula; López-García, Maria T; Rioseras, Beatriz; Sánchez, Jesús; Manteca, Angel

2013-05-01

Streptomycetes comprise very important industrial bacteria, producing two-thirds of all clinically relevant secondary metabolites. They are mycelial microorganisms with complex developmental cycles that include programmed cell death (PCD) and sporulation. Industrial fermentations are usually performed in liquid cultures (large bioreactors), conditions in which Streptomyces strains generally do not sporulate, and it was traditionally assumed that there was no differentiation. In this work, we review the current knowledge on Streptomyces pre-sporulation stages of Streptomyces differentiation. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

NBS1 plays a synergistic role with telomerase in the maintenance of telomeres in Arabidopsis thaliana.

PubMed

Najdekrova, Lucie; Siroky, Jiri

2012-09-17

Telomeres, as elaborate nucleo-protein complexes, ensure chromosomal stability. When impaired, the ends of linear chromosomes can be recognised by cellular repair mechanisms as double-strand DNA breaks and can be healed by non-homologous-end-joining activities to produce dicentric chromosomes. During cell divisions, particularly during anaphase, dicentrics can break, thus producing naked chromosome tips susceptible to additional unwanted chromosome fusion. Many telomere-building protein complexes are associated with telomeres to ensure their proper capping function. It has been found however, that a number of repair complexes also contribute to telomere stability. We used Arabidopsis thaliana to study the possible functions of the DNA repair subunit, NBS1, in telomere homeostasis using knockout nbs1 mutants. The results showed that although NBS1-deficient plants were viable, lacked any sign of developmental aberration and produced fertile seeds through many generations upon self-fertilisation, plants also missing the functional telomerase (double mutants), rapidly, within three generations, displayed severe developmental defects. Cytogenetic inspection of cycling somatic cells revealed a very early onset of massive genome instability. Molecular methods used for examining the length of telomeres in double homozygous mutants detected much faster telomere shortening than in plants deficient in telomerase gene alone. Our findings suggest that NBS1 acts in concert with telomerase and plays a profound role in plant telomere renewal.

Drosophila COP9 signalosome subunit 7 interacts with multiple genomic loci to regulate development

PubMed Central

Singer, Ruth; Atar, Shimshi; Atias, Osnat; Oron, Efrat; Segal, Daniel; Hirsch, Joel A.; Tuller, Tamir; Orian, Amir; Chamovitz, Daniel A.

2014-01-01

The COP9 signalosome protein complex has a central role in the regulation of development of multicellular organisms. While the function of this complex in ubiquitin-mediated protein degradation is well established, results over the past few years have hinted that the COP9 signalosome may function more broadly in the regulation of gene expression. Here, using DamID technology, we show that COP9 signalosome subunit 7 functionally associates with a large number of genomic loci in the Drosophila genome, and show that the expression of many genes within these loci is COP9 signalosome-dependent. This association is likely direct as we show CSN7 binds DNA in vitro. The genes targeted by CSN7 are preferentially enriched for transcriptionally active regions of the genome, and are involved in the regulation of distinct gene ontology groupings including imaginal disc development and cell-cycle control. In accord, loss of CSN7 function leads to cell-cycle delay and altered wing development. These results indicate that CSN7, and by extension the entire COP9 signalosome, functions directly in transcriptional control. While the COP9 signalosome protein complex has long been known to regulate protein degradation, here we expand the role of this complex by showing that subunit 7 binds DNA in vitro and functions directly in vivo in transcriptional control of developmentally important pathways that are relevant for human health. PMID:25106867

Sordaria macrospora, a model organism to study fungal cellular development.

PubMed

Engh, Ines; Nowrousian, Minou; Kück, Ulrich

2010-12-01

During the development of multicellular eukaryotes, the processes of cellular growth and organogenesis are tightly coordinated. Since the 1940s, filamentous fungi have served as genetic model organisms to decipher basic mechanisms underlying eukaryotic cell differentiation. Here, we focus on Sordaria macrospora, a homothallic ascomycete and important model organism for developmental biology. During its sexual life cycle, S. macrospora forms three-dimensional fruiting bodies, a complex process involving the formation of different cell types. S. macrospora can be used for genetic, biochemical and cellular experimental approaches since diverse tools, including fluorescence microscopy, a marker recycling system and gene libraries, are available. Moreover, the genome of S. macrospora has been sequenced and allows functional genomics analyses. Over the past years, our group has generated and analysed a number of developmental mutants which has greatly enhanced our fundamental understanding about fungal morphogenesis. In addition, our recent research activities have established a link between developmental proteins and conserved signalling cascades, ultimately leading to a regulatory network controlling differentiation processes in a eukaryotic model organism. This review summarizes the results of our recent findings, thus advancing current knowledge of the general principles and paradigms underpinning eukaryotic cell differentiation and development. Copyright © 2010 Elsevier GmbH. All rights reserved.

A role for post-transcriptional control of endoplasmic reticulum dynamics and function in C. elegans germline stem cell maintenance.

PubMed

Maheshwari, Richa; Pushpa, Kumari; Subramaniam, Kuppuswamy

2016-09-01

Membrane-bound receptors, which are crucial for mediating several key developmental signals, are synthesized on endoplasmic reticulum (ER). The functional integrity of ER must therefore be important for the regulation of at least some developmental programs. However, the developmental control of ER function is not well understood. Here, we identify the C. elegans protein FARL-11, an ortholog of the mammalian STRIPAK complex component STRIP1/2 (FAM40A/B), as an ER protein. In the C. elegans embryo, we find that FARL-11 is essential for the cell cycle-dependent morphological changes of ER and for embryonic viability. In the germline, FARL-11 is required for normal ER morphology and for membrane localization of the GLP-1/Notch receptor involved in germline stem cell (GSC) maintenance. Furthermore, we provide evidence that PUF-8, a key translational regulator in the germline, promotes the translation of farl-11 mRNA. These findings reveal that ER form and function in the C. elegans germline are post-transcriptionally regulated and essential for the niche-GSC signaling mediated by GLP-1. © 2016. Published by The Company of Biologists Ltd.

Cell cycle arrest in the jewel wasp Nasonia vitripennis in larval diapause.

PubMed

Shimizu, Yuta; Mukai, Ayumu; Goto, Shin G

2018-04-01

Insects enter diapause to synchronise their life cycle with biotic and abiotic environmental conditions favourable for their development, reproduction, and survival. One of the most noticeable characteristics of diapause is the blockage of ontogeny. Although this blockage should occur with the cessation of cellular proliferation, i.e. cell cycle arrest, it was confirmed only in a few insect species and information on the molecular pathways involved in cell cycle arrest is limited. In the present study, we investigated developmental and cell cycle arrest in diapause larvae of the jewel wasp Nasonia vitripennis. Developmental and cell cycle arrest occur in the early fourth instar larval stage of N. vitripennis under short days. By entering diapause, the S fraction of the cell cycle disappears and approximately 80% and 20% of cells arrest their cell cycle in the G0/G1 and G2 phases, respectively. We further investigated expression of cell cycle regulatory genes and some housekeeping genes to dissect molecular mechanisms underlying the cell cycle arrest. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Growth of Complexity and Accuracy in L2 French: Past Observations and Recent Applications of Developmental Stages

ERIC Educational Resources Information Center

Agren, Malin; Granfeldt, Jonas; Schlyter, Suzanne

2012-01-01

This chapter addresses the question of the growth of accuracy and complexity in L2 French from the perspective of developmental sequences of morphosyntax, developmental stages and linguistic profiling. The six developmental stages for L2 French proposed by Bartning and Schlyter (2004) are presented and exemplified and new results are added to the…

Conditional mutation of Smc5 in mouse embryonic stem cells perturbs condensin localization and mitotic progression.

PubMed

Pryzhkova, Marina V; Jordan, Philip W

2016-04-15

Correct duplication of stem cell genetic material and its appropriate segregation into daughter cells are requisites for tissue, organ and organism homeostasis. Disruption of stem cell genomic integrity can lead to developmental abnormalities and cancer. Roles of the Smc5/6 structural maintenance of chromosomes complex in pluripotent stem cell genome maintenance have not been investigated, despite its important roles in DNA synthesis, DNA repair and chromosome segregation as evaluated in other model systems. Using mouse embryonic stem cells (mESCs) with a conditional knockout allele of Smc5, we showed that Smc5 protein depletion resulted in destabilization of the Smc5/6 complex, accumulation of cells in G2 phase of the cell cycle and apoptosis. Detailed assessment of mitotic mESCs revealed abnormal condensin distribution and perturbed chromosome segregation, accompanied by irregular spindle morphology, lagging chromosomes and DNA bridges. Mutation of Smc5 resulted in retention of Aurora B kinase and enrichment of condensin on chromosome arms. Furthermore, we observed reduced levels of Polo-like kinase 1 at kinetochores during mitosis. Our study reveals crucial requirements of the Smc5/6 complex during cell cycle progression and for stem cell genome maintenance. © 2016. Published by The Company of Biologists Ltd.

Pleiotropy in the wild: the dormancy gene DOG1 exerts cascading control on life cycles.

PubMed

Chiang, George C K; Barua, Deepak; Dittmar, Emily; Kramer, Elena M; de Casas, Rafael Rubio; Donohue, Kathleen

2013-03-01

In the wild, organismal life cycles occur within seasonal cycles, so shifts in the timing of developmental transitions can alter the seasonal environment experienced subsequently. Effects of genes that control the timing of prior developmental events can therefore be magnified in the wild because they determine seasonal conditions experienced by subsequent life stages, which can influence subsequent phenotypic expression. We examined such environmentally induced pleiotropy of developmental-timing genes in a field experiment with Arabidopsis thaliana. When studied in the field under natural seasonal variation, an A. thaliana seed-dormancy gene, Delay Of Germination 1 (DOG1), was found to influence not only germination, but also flowering time, overall life history, and fitness. Flowering time of the previous generation, in turn, imposed maternal effects that altered germination, the effects of DOG1 alleles, and the direction of natural selection on these alleles. Thus under natural conditions, germination genes act as flowering genes and potentially vice versa. These results illustrate how seasonal environmental variation can alter pleiotropic effects of developmental-timing genes, such that effects of genes that regulate prior life stages ramify to influence subsequent life stages. In this case, one gene acting at the seed stage impacted the entire life cycle. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Stereotyped behavior of severely disabled children in classroom and free-play settings.

PubMed

Thompson, T J; Berkson, G

1985-05-01

The relationships between stereotyped behavior, object manipulation, self-manipulation, teacher attention, and various developmental measures were examined in 101 severely developmentally disabled children in their classrooms and a free-play setting. Stereotyped behavior without objects was positively correlated with self-manipulation and CA and was negatively correlated with complex object manipulation, developmental age, developmental quotient, and teacher attention. Stereotyped behavior with objects was negatively correlated with complex object manipulation. Partial correlations showed that age, self-manipulation, and developmental age shared unique variance with stereotyped behavior without objects.

Evolutionary lability of a complex life cycle in the aphid genus Brachycaudus.

PubMed

Emmanuelle, Jousselin; Gwenaelle, Genson; Armelle, Coeur d'acier

2010-09-28

Most aphid species complete their life cycle on the same set of host-plant species, but some (heteroecious species) alternate between different hosts, migrating from primary (woody) to secondary (herbaceous) host plants. The evolutionary processes behind the evolution of this complex life cycle have often been debated. One widely accepted scenario is that heteroecy evolved from monoecy on woody host plants. Several shifts towards monoecy on herbaceous plants have subsequently occurred and resulted in the radiation of aphids. Host alternation would have persisted in some cases due to developmental constraints preventing aphids from shifting their entire life cycle to herbaceous hosts (which are thought to be more favourable). According to this scenario, if aphids lose their primary host during evolution they should not regain it. The genus Brachycaudus includes species with all the types of life cycle (monoecy on woody plants, heteroecy, monoecy on herbs). We used this genus to test hypotheses concerning the evolution of life cycles in aphids. Phylogenetic investigation and character reconstruction suggest that life cycle is evolutionary labile in the genus. Though ancestral character states can be ambiguous depending on optimization methods, all analyses suggest that transitions from monoecy on herbs towards heteroecy have occurred several times. Transitions from heteroecy towards monoecy, are also likely. There have been many shifts in feeding behaviour but we found no significant correlation between life cycle changes and changes in diet. The transitions from monoecy on herbs towards heteroecy observed in this study go against a widely accepted evolutionary scenario: aphids in the genus Brachycaudus seem to be able to recapture their supposedly ancestral woody host. This suggests that the determinants of host alternation are probably not as complicated as previously thought. Definitive proofs of the lability of life cycle in Brachycaudus will necessitate investigation of these determinants. Life cycle changes, whether corresponding to the loss or acquisition of a primary host, necessarily promote speciation, by inducing shifts of the reproductive phase on different plants. We suggest that the evolutionary lability of life cycle may have driven speciation events in the Brachycaudus genus.

Avian predation pressure as a potential driver of periodical cicada cycle length.

PubMed

Koenig, Walter D; Liebhold, Andrew M

2013-01-01

The extraordinarily long life cycles, synchronous emergences at 13- or 17-year intervals, and complex geographic distribution of periodical cicadas (Magicicada spp.) in eastern North America are a long-standing evolutionary enigma. Although a variety of factors, including satiation of aboveground predators and avoidance of interbrood hybridization, have been hypothesized to shape the evolution of this system, no empirical support for these mechanisms has previously been reported, beyond the observation that bird predation can extirpate small, experimentally mistimed emergences. Here we show that periodical cicada emergences appear to set populations of potential avian predators on numerical trajectories that result in significantly lower potential predation pressure during the subsequent emergence. This result provides new support for the importance of predators in shaping periodical cicada life history, offers an ecological rationale for why emergences are synchronized at the observed multiyear intervals, and may explain some of the developmental plasticity observed in these unique insects.

Developmental Changes in Ultradian Sleep Cycles across Early Childhood.

PubMed

Lopp, Sean; Navidi, William; Achermann, Peter; LeBourgeois, Monique; Diniz Behn, Cecilia

2017-02-01

Nocturnal human sleep is composed of cycles between rapid eye movement (REM) sleep and non-REM (NREM) sleep. In adults, the structure of ultradian cycles between NREM and REM sleep is well characterized; however, less is known about the developmental trajectories of ultradian sleep cycles across early childhood. Cross-sectional studies indicate that the rapid ultradian cycling of active-quiet sleep in infancy shifts to a more adult-like pattern of NREM-REM sleep cycling by the school-age years, yet longitudinal studies elucidating the details of this transition are scarce. To address this gap, we examined ultradian cycling during nocturnal sleep following 13 h of prior wakefulness in 8 healthy children at 3 longitudinal points: 2Y (2.5-3.0 years of age), 3Y (3.5-4.0 years of age), and 5Y (5.5-6.0 years of age). We found that the length of ultradian cycles increased with age as a result of increased NREM sleep episode duration. In addition, we observed a significant decrease in the number of NREM sleep episodes as well as a nonsignificant trend for a decrease in the number of cycles with increasing age. Together, these findings suggest a concurrent change in which cycle duration increases and the number of cycles decreases across development. We also found that, consistent with data from adolescents and adults, the duration of NREM sleep episodes decreased with time since lights-off whereas the duration of REM sleep episodes increased over this time period. These results indicate the presence of circadian modulation of nocturnal sleep in preschool children. In addition to characterizing changes in ultradian cycling in healthy children ages 2 to 5 years, this work describes a developmental model that may provide insights into the emergence of normal adult REM sleep regulatory circuitry as well as potential trajectories of dysregulated ultradian cycles such as those associated with affective disorders.

Developmental Changes in Ultradian Sleep Cycles across Early Childhood: Preliminary Insights

PubMed Central

Lopp, Sean; Navidi, William; Achermann, Peter; LeBourgeois, Monique; Diniz Behn, Cecilia

2017-01-01

Nocturnal human sleep is composed of cycles between rapid eye movement (REM) sleep and non-REM (NREM) sleep. In adults, the structure of ultradian cycles between NREM and REM sleep is well characterized; however, less is known about the developmental trajectories of ultradian sleep cycles across early childhood. Cross-sectional studies indicate that the rapid ultradian cycling of active-quiet sleep in infancy shifts to a more adult-like pattern of NREM-REM sleep cycling by the school-age years, yet longitudinal studies elucidating the details of this transition are scarce. To address this gap, we examined ultradian cycling during nocturnal sleep following 13 h of prior wakefulness in 8 healthy children at 3 longitudinal points: 2Y (2.5-3.0 years of age), 3Y (3.5-4.0 years of age), and 5Y (5.5-6.0 years of age). We found that the length of ultradian cycles increased with age as a result of increased NREM sleep episode duration. In addition, we observed a significant decrease in the number of NREM sleep episodes as well as a nonsignificant trend for a decrease in the number of cycles with increasing age. Together, these findings suggest a concurrent change in which cycle duration increases and the number of cycles decreases across development. We also found that, consistent with data from adolescents and adults, the duration of NREM sleep episodes decreased with time since lights-off whereas the duration of REM sleep episodes increased over this time period. These results indicate the presence of circadian modulation of nocturnal sleep in preschool children. In addition to characterizing changes in ultradian cycling in healthy children ages 2 to 5 years, this work describes a developmental model that may provide insights into the emergence of normal adult REM sleep regulatory circuitry as well as potential trajectories of dysregulated ultradian cycles such as those associated with affective disorders. PMID:28088873

Reproducible and controllable light induction of in vitro fruiting of the white-rot basidiomycete Pleurotus ostreatus.

PubMed

Arjona, Davinia; Aragón, Carlos; Aguilera, José Antonio; Ramírez, Lucía; Pisabarro, Antonio G

2009-05-01

Fruiting is a crucial developmental process in basidiomycetes yet the genetic and molecular factors that control it are not yet fully understood. The search for fruiting inducers is of major relevance for both basic research and for their use in industrial applications. In this paper, an efficient and reproducible protocol for controlled fruiting induction of Pleurotus ostreatus growing on synthetic medium is described. The protocol is based on the control of light intensity and photoperiod and permits the life cycle for this fungus to be completed in less than two weeks. The fruiting bodies produced by this method release fertile spores after 4-5 d of culture. Our results indicate that fruiting induction is solely dependent on the illumination regime and that it occurs long before the available nutrients are depleted in the culture. This protocol will greatly facilitate molecular and developmental biology research in this fungus as it avoids the need for complex culture media based on lignocellulosic materials or the use of chemical inducers.

Adolescent education: an opportunity to create a Developmental Origins of Health and Disease (DOHaD) circuit breaker.

PubMed

Bay, J L; Vickers, M H

2016-10-01

Health before conception, and periconceptional nutritional environments, contribute to conditioning of later-life health and disease. Health behaviors developed during adolescence continue into adulthood. Thus, even when the gap between pregnancy and adolescence is substantial, behaviors developed during adolescence influence later-life non-communicable disease (NCD) vulnerability in offspring. Consequently, adolescence is an important life phase where development of positive health behaviors can contribute to disruption of transgenerational cycles of NCD risk. Schooling is a core activity during adolescence. Modern curricula focus on development of capabilities associated with critical, engaged citizenship, empowering learning that supports action-based engagement in complex issues. Contexts relevant to adolescents and their communities, such as the NCD epidemic, are used to facilitate learning. Thus, engaging the education sector as participants in the work of the Developmental Origins of Health and Disease community offers an important strategy to capture the potential of adolescence as a life stage for transgenerational primary prevention of obesity and NCD risk.

Effect of thermal cycling. Final report, April 1985-January 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobs, S.F.

The objective of this effort is to evaluate the stability of low expansion Zerodur, developmental Zerodur, ULE, and Cer-Vit as possible substrate materials for high energy laser mirrors. This effort will determine whether there is instability in developmental Zerodur, ULE and Cer-Vit over operating temperatures and coating temperatures (300-475K). Zerodur has already been shown to exhibit instability. Thermal cycling will be investigated as a possible approach to eliminate or reduce hysteresis. The effect of polishing on hysteresis will also be investigated.

Effect of thermal cycling

NASA Astrophysics Data System (ADS)

Jacobs, Stephen F.

1988-05-01

The objective of this effort is to evaluate the stability of low expansion Zerodur, developmental Zerodur, ULE, and Cer-Vit as possible substrate materials for high energy laser mirrors. This effort will determine whether there is instability in developmental Zerodur, ULE and Cer-Vit over operating temperatures and coating temperatures (300 to 475 K). Zerodur has already been shown to exhibit instability. Thermal cycling will be investigated as a possible approach to eliminate or reduce hysteresis. The effect of polishing on hysteresis will also be investigated.

Treatment with Ca2+ ionophore improves embryo development and outcome in cases with previous developmental problems: a prospective multicenter study.

PubMed

Ebner, T; Oppelt, P; Wöber, M; Staples, P; Mayer, R B; Sonnleitner, U; Bulfon-Vogl, S; Gruber, I; Haid, A E; Shebl, O

2015-01-01

Does calcium ionophore treatment (A23187, calcimycin) improve embryo development and outcome in patients with a history of developmental problems/arrest? Application of A23187 leads to increased rates of cleavage to 2-cell stage, blastocyst formation and clinical pregnancy/live birth. Studies on lower animals indicate that changes in intracellular free calcium trigger and regulate the events of cell division. In humans, calcium fluctuations were detected with a peak shortly before cell division. Interestingly, these calcium oscillations disappeared in arrested embryos. Mitotic division blocked with a Ca(2+) chelator could be restored by means of ionophores in an animal model. This prospective, multicenter (five Austrian centers), uncontrolled intervention study (duration 1 year) includes 57 patients who provided informed consent. Inclusion criteria were complete embryo developmental arrest in a previous cycle (no transfer), complete developmental delay (no morula/blastocyst on Day 5), or reduced blastocyst formation on Day 5 (≤15%). Severe male factor patients and patients with <30% fertilization rate after ICSI were excluded because these would be routine indications for ionophore usage. The total of the 57 immediately preceding cycles in the same patients constituted the control cycles/control group. In the treatment cycles, all metaphase II-oocytes were exposed to a commercially available ready-to-use ionophore for 15 min immediately after ICSI. After a three-step washing procedure, in vitro culture was performed as in the control cycles, up to blastocyst stage when achievable. Fertilization rate did not differ (75.4 versus 73.2%); however, further cleavage to 2-cell stage was significantly higher (P < 0.001) in the ionophore group (98.5%) when compared with the control cycles (91.9%). In addition, significantly more (P < 0.05) blastocysts formed on Day 5 in the study compared with the control group (47.6 versus 5.5%, respectively) and this was associated with a significant increase (P < 0.01) in the rates of implantation (44.4 versus 12.5%), clinical pregnancy (45.1 versus 12.8%) and live birth (45.1 versus 12.8%). All babies born at the time of writing (22/28) were healthy. The frequency of patients showing embryo developmental problems was expected to be low; therefore, a multicenter approach was chosen in order to increase sample size. In one-third of the cycles, the clinician or patient requested a change of stimulation protocol; however, this did not influence the developmental rate of embryos. This is the first evidence that developmental incompetence of embryos is an additional indication for ionophore treatment. The present approach is exclusively for overcoming cleavage arrest. No funding received. T.E. reports fees from Gynemed, outside the submitted work. All co-authors have no interest to declare. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Factors Affecting the Development of Somatic Cell Nuclear Transfer Embryos in Cattle

PubMed Central

AKAGI, Satoshi; MATSUKAWA, Kazutsugu; TAKAHASHI, Seiya

2014-01-01

Nuclear transfer is a complex multistep procedure that includes oocyte maturation, cell cycle synchronization of donor cells, enucleation, cell fusion, oocyte activation and embryo culture. Therefore, many factors are believed to contribute to the success of embryo development following nuclear transfer. Numerous attempts to improve cloning efficiency have been conducted since the birth of the first sheep by somatic cell nuclear transfer. However, the efficiency of somatic cell cloning has remained low, and applications have been limited. In this review, we discuss some of the factors that affect the developmental ability of somatic cell nuclear transfer embryos in cattle. PMID:25341701

COP9 Signalosome Subunit Csn8 Is Involved in Maintaining Proper Duration of the G1 Phase*

PubMed Central

Liu, Cheng; Guo, Li-Quan; Menon, Suchithra; Jin, Dan; Pick, Elah; Wang, Xuejun; Deng, Xing Wang; Wei, Ning

2013-01-01

The COP9 signalosome (CSN) is a conserved protein complex known to be involved in developmental processes of eukaryotic organisms. Genetic disruption of a CSN gene causes arrest during early embryonic development in mice. The Csn8 subunit is the smallest and the least conserved subunit, being absent from the CSN complex of several fungal species. Nevertheless, Csn8 is an integral component of the CSN complex in higher eukaryotes, where it is essential for life. By characterizing the mouse embryonic fibroblasts (MEFs) that express Csn8 at a low level, we found that Csn8 plays an important role in maintaining the proper duration of the G1 phase of the cell cycle. A decreased level of Csn8, either in Csn8 hypomorphic MEFs or following siRNA-mediated knockdown in HeLa cells, accelerated cell growth rate. Csn8 hypomorphic MEFs exhibited a shortened G1 duration and affected expression of G1 regulators. In contrast to Csn8, down-regulation of Csn5 impaired cell proliferation. Csn5 proteins were found both as a component of the CSN complex and outside of CSN (Csn5-f), and the amount of Csn5-f relative to CSN was increased in the Csn8 hypomorphic cells. We conclude that CSN harbors both positive and negative regulators of the cell cycle and therefore is poised to influence the fate of a cell at the crossroad of cell division, differentiation, and senescence. PMID:23689509

Drosophila COP9 signalosome subunit 7 interacts with multiple genomic loci to regulate development.

PubMed

Singer, Ruth; Atar, Shimshi; Atias, Osnat; Oron, Efrat; Segal, Daniel; Hirsch, Joel A; Tuller, Tamir; Orian, Amir; Chamovitz, Daniel A

2014-09-01

The COP9 signalosome protein complex has a central role in the regulation of development of multicellular organisms. While the function of this complex in ubiquitin-mediated protein degradation is well established, results over the past few years have hinted that the COP9 signalosome may function more broadly in the regulation of gene expression. Here, using DamID technology, we show that COP9 signalosome subunit 7 functionally associates with a large number of genomic loci in the Drosophila genome, and show that the expression of many genes within these loci is COP9 signalosome-dependent. This association is likely direct as we show CSN7 binds DNA in vitro. The genes targeted by CSN7 are preferentially enriched for transcriptionally active regions of the genome, and are involved in the regulation of distinct gene ontology groupings including imaginal disc development and cell-cycle control. In accord, loss of CSN7 function leads to cell-cycle delay and altered wing development. These results indicate that CSN7, and by extension the entire COP9 signalosome, functions directly in transcriptional control. While the COP9 signalosome protein complex has long been known to regulate protein degradation, here we expand the role of this complex by showing that subunit 7 binds DNA in vitro and functions directly in vivo in transcriptional control of developmentally important pathways that are relevant for human health. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

A DNA damage checkpoint pathway coordinates the division of dikaryotic cells in the ink cap mushroom Coprinopsis cinerea.

PubMed

de Sena-Tomás, Carmen; Navarro-González, Mónica; Kües, Ursula; Pérez-Martín, José

2013-09-01

The fungal fruiting body or mushroom is a multicellular structure essential for sexual reproduction. It is composed of dikaryotic cells that contain one haploid nucleus from each mating partner sharing the same cytoplasm without undergoing nuclear fusion. In the mushroom, the pileus bears the hymenium, a layer of cells that includes the specialized basidia in which nuclear fusion, meiosis, and sporulation occur. Coprinopsis cinerea is a well-known model fungus used to study developmental processes associated with the formation of the fruiting body. Here we describe that knocking down the expression of Atr1 and Chk1, two kinases shown to be involved in the response to DNA damage in a number of eukaryotic organisms, dramatically impairs the ability to develop fruiting bodies in C. cinerea, as well as other developmental decisions such as sclerotia formation. These developmental defects correlated with the impairment in silenced strains to sustain an appropriated dikaryotic cell cycle. Dikaryotic cells in which chk1 or atr1 genes were silenced displayed a higher level of asynchronous mitosis and as a consequence aberrant cells carrying an unbalanced dose of nuclei. Since fruiting body initiation is dependent on the balanced mating-type regulator doses present in the dikaryon, we believe that the observed developmental defects were a consequence of the impaired cell cycle in the dikaryon. Our results suggest a connection between the DNA damage response cascade, cell cycle regulation, and developmental processes in this fungus.

Developmental capacity of in vitro-matured human oocytes retrieved from polycystic ovary syndrome ovaries containing no follicles larger than 6 mm.

PubMed

Guzman, Luis; Ortega-Hrepich, Carolina; Albuz, Firas K; Verheyen, Greta; Devroey, Paul; Smitz, Johan; De Vos, Michel

2012-08-01

To test the developmental competence of oocytes in a nonhCG-triggered in vitro maturation (IVM) system when oocyte-cumulus complexes (OCC) are retrieved from antral follicles with a diameter of <6 mm. Prospective cohort study. Tertiary university-based referral center. From January 2010 to September 2011, 121 patients with polycystic ovaries/polycystic ovary syndrome underwent 239 IVM cycles in total. In 58 of these cycles (44 patients), all antral follicles had a diameter of <6 mm on the day of oocyte retrieval. NonhCG-triggered IVM of oocytes, fresh or vitrified/warmed embryo transfer (ET). Oocyte diameter, maturation rate, fertilization rate, embryo development and morphology, implantation rate, clinical pregnancy rate, ongoing pregnancy rate. Oocyte retrieval yielded 16.7 OCC/cycle, and 50.8% of oocytes completed IVM. The mean oocyte diameter increased from 108.8 ± 4.3 μm to 111.9 ± 4.1 μm after IVM. Mean fertilization rate was 63.7%, and 45.4% of 2-pronuclei oocytes developed into a morphologically good-quality embryo on day 3 after intracytoplasmic sperm injection. Fresh ET resulted in two ongoing pregnancies (2/37; 5.4%). Deferred vitrified-warmed ET led to an ongoing pregnancy rate of 34.6% (9/24). Three healthy babies were born and eight pregnancies were still ongoing. Oocytes retrieved from follicles with a diameter of <6 mm grow during a 40-hour IVM culture can acquire full competence in vitro, as illustrated by their development into healthy offspring. Endometrial quality appears to be a crucial determinant of pregnancy after nonhCG-triggered IVM. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Drosophila melanogaster as a model system for assessing development under conditions of microgravity

NASA Technical Reports Server (NTRS)

Abbott, M. K.; Hilgenfeld, R. B.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

1992-01-01

More is known about the regulation of early developmental events in Drosophila than any other animal. In addition, its size and short life cycle make it a facile experimental system. Since developmental perturbations have been demonstrated when both oogenesis and embryogenesis occur in the space environment, there is a strong rationale for using this organism for the elucidation of specific gravity-sensitive developmental events.

Jaw muscle development as evidence for embryonic repatterning in direct-developing frogs.

PubMed Central

Hanken, J; Klymkowsky, M W; Alley, K E; Jennings, D H

1997-01-01

The Puerto Rican direct-developing frog Eleutherodactylus coqui (Leptodactylidae) displays a novel mode of jaw muscle development for anuran amphibians. Unlike metamorphosing species, several larval-specific features never form in E. coqui; embryonic muscle primordia initially assume an abbreviated, mid-metamorphic configuration that is soon remodelled to form the adult morphology before hatching. Also lacking are both the distinct population of larval myofibres and the conspicuous, larval-to-adult myofibre turnover that are characteristic of muscle development in metamorphosing species. These modifications are part of a comprehensive alteration in embryonic cranial patterning that has accompanied life history evolution in this highly speciose lineage. Embryonic 'repatterning' in Eleutherodactylus may reflect underlying developmental mechanisms that mediate the integrated evolution of complex structures. Such mechanisms may also facilitate, in organisms with a primitively complex life cycle, the evolutionary dissociation of embryonic, larval, and adult features. PMID:9332017

Systems Modeling in Developmental Toxicity

EPA Science Inventory

An individual starts off as a single cell, the progeny of which form complex structures that are themselves integrated into progressively larger systems. Developmental biology is concerned with how this cellular complexity and patterning arises through orchestration of cell divi...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, E.M.

Human reproduction and development is a cycle of interdependent events. Virtually all of its phases have been shown to be the primary target of one or more non-mutagenic exogenous agents. Such agents interfere with certain of the countless epigenetic or ontogenic events essential for normal completion of the cycle. Mutagens disrupt this cycle at some points, but the overwhelming majority of reproductive and developmental toxins are not mutagenic. As in all aspects of toxicology, the reproductive and developmental effects of chemicals are determined by the intrinsic nature of the chemical, the quantity of the chemical exposure, the duration of exposuremore » and the stage of the cycle at which it occurs. Signs of reproductive toxicity range from reduced fertility to spontaneous abortion. Adverse effects on the conceptus are categorized as functional deficits, developmental retardation, structural abnormality and death. One or more of these is anticipated to occur as a result of excess exposure to most chemicals. Although the degree of hazard and risk potential can be calculated in each instance, chemicals differ markedly in their ability to interfere with reproduction and/or development. Standardized methods for reproductive and developmental toxicity safety evaluation are available for detecting adverse effects upon any aspect of reproduction and development. Data currently available establish that these state-of-the-art tests conducted in laboratory animals are often highly predictive of the type of adverse effect a particular chemical will have in humans, as well as the exposure level at which it will occur. By adding a modest safety factor to the no-observed-effect-level of well-executed animal studies, safe human exposure levels can be established. 40 references.« less

Non-coding RNA networks underlying cognitive disorders across the lifespan

PubMed Central

Qureshi, Irfan A.; Mehler, Mark F.

2011-01-01

Non-coding RNAs (ncRNAs) and their associated regulatory networks are increasingly being implicated in mediating a complex repertoire of neurobiological functions. Cognitive and behavioral processes are proving to be no exception. Here, we discuss the emergence of many novel, diverse, and rapidly expanding classes and subclasses of short and long ncRNAs. We briefly review the life cycles and molecular functions of these ncRNAs. We also examine how ncRNA circuitry mediates brain development, plasticity, stress responses, and aging and highlight its potential roles in the pathophysiology of cognitive disorders, including neural developmental and age-associated neurodegenerative diseases as well as those that manifest throughout the lifespan. PMID:21411369

Compositional shifts in root-associated bacterial and archaeal microbiota track the plant life cycle in field-grown rice

PubMed Central

Edwards, Joseph A.; Santos-Medellín, Christian M.; Liechty, Zachary S.; Nguyen, Bao; Lurie, Eugene; Eason, Shane; Phillips, Gregory

2018-01-01

Bacterial communities associated with roots impact the health and nutrition of the host plant. The dynamics of these microbial assemblies over the plant life cycle are, however, not well understood. Here, we use dense temporal sampling of 1,510 samples from root spatial compartments to characterize the bacterial and archaeal components of the root-associated microbiota of field grown rice (Oryza sativa) over the course of 3 consecutive growing seasons, as well as 2 sites in diverse geographic regions. The root microbiota was found to be highly dynamic during the vegetative phase of plant growth and then stabilized compositionally for the remainder of the life cycle. Bacterial and archaeal taxa conserved between field sites were defined as predictive features of rice plant age by modeling using a random forest approach. The age-prediction models revealed that drought-stressed plants have developmentally immature microbiota compared to unstressed plants. Further, by using genotypes with varying developmental rates, we show that shifts in the microbiome are correlated with rates of developmental transitions rather than age alone, such that different microbiota compositions reflect juvenile and adult life stages. These results suggest a model for successional dynamics of the root-associated microbiota over the plant life cycle. PMID:29474469

Compositional shifts in root-associated bacterial and archaeal microbiota track the plant life cycle in field-grown rice.

PubMed

Edwards, Joseph A; Santos-Medellín, Christian M; Liechty, Zachary S; Nguyen, Bao; Lurie, Eugene; Eason, Shane; Phillips, Gregory; Sundaresan, Venkatesan

2018-02-01

Bacterial communities associated with roots impact the health and nutrition of the host plant. The dynamics of these microbial assemblies over the plant life cycle are, however, not well understood. Here, we use dense temporal sampling of 1,510 samples from root spatial compartments to characterize the bacterial and archaeal components of the root-associated microbiota of field grown rice (Oryza sativa) over the course of 3 consecutive growing seasons, as well as 2 sites in diverse geographic regions. The root microbiota was found to be highly dynamic during the vegetative phase of plant growth and then stabilized compositionally for the remainder of the life cycle. Bacterial and archaeal taxa conserved between field sites were defined as predictive features of rice plant age by modeling using a random forest approach. The age-prediction models revealed that drought-stressed plants have developmentally immature microbiota compared to unstressed plants. Further, by using genotypes with varying developmental rates, we show that shifts in the microbiome are correlated with rates of developmental transitions rather than age alone, such that different microbiota compositions reflect juvenile and adult life stages. These results suggest a model for successional dynamics of the root-associated microbiota over the plant life cycle.

Macrophage/epithelium cross-talk regulates cell cycle progression and migration in pancreatic progenitors.

PubMed

Mussar, Kristin; Tucker, Andrew; McLennan, Linsey; Gearhart, Addie; Jimenez-Caliani, Antonio J; Cirulli, Vincenzo; Crisa, Laura

2014-01-01

Macrophages populate the mesenchymal compartment of all organs during embryogenesis and have been shown to support tissue organogenesis and regeneration by regulating remodeling of the extracellular microenvironment. Whether this mesenchymal component can also dictate select developmental decisions in epithelia is unknown. Here, using the embryonic pancreatic epithelium as model system, we show that macrophages drive the epithelium to execute two developmentally important choices, i.e. the exit from cell cycle and the acquisition of a migratory phenotype. We demonstrate that these developmental decisions are effectively imparted by macrophages activated toward an M2 fetal-like functional state, and involve modulation of the adhesion receptor NCAM and an uncommon "paired-less" isoform of the transcription factor PAX6 in the epithelium. Over-expression of this PAX6 variant in pancreatic epithelia controls both cell motility and cell cycle progression in a gene-dosage dependent fashion. Importantly, induction of these phenotypes in embryonic pancreatic transplants by M2 macrophages in vivo is associated with an increased frequency of endocrine-committed cells emerging from ductal progenitor pools. These results identify M2 macrophages as key effectors capable of coordinating epithelial cell cycle withdrawal and cell migration, two events critical to pancreatic progenitors' delamination and progression toward their differentiated fates.

Contingency Detection in a Complex World: A Developmental Model and Implications for Atypical Development

ERIC Educational Resources Information Center

Northrup, Jessie Bolz

2017-01-01

The present article proposes a new developmental model of how young infants adapt and respond to complex contingencies in their environment, and how this influences development. The model proposes that typically developing infants adjust to an increasingly complex environment in ways that make it easier for them to allocate limited attentional…

Increased leaf mesophyll porosity following transient retinoblastoma-related protein silencing is revealed by microcomputed tomography imaging and leads to a system-level physiological response to the altered cell division pattern

PubMed Central

Dorca-Fornell, Carmen; Pajor, Radoslaw; Lehmeier, Christoph; Pérez-Bueno, Marísa; Bauch, Marion; Sloan, Jen; Osborne, Colin; Rolfe, Stephen; Sturrock, Craig; Mooney, Sacha; Fleming, Andrew

2013-01-01

The causal relationship between cell division and growth in plants is complex. Although altered expression of cell-cycle genes frequently leads to altered organ growth, there are many examples where manipulation of the division machinery leads to a limited outcome at the level of organ form, despite changes in constituent cell size. One possibility, which has been under-explored, is that altered division patterns resulting from manipulation of cell-cycle gene expression alter the physiology of the organ, and that this has an effect on growth. We performed a series of experiments on retinoblastoma-related protein (RBR), a well characterized regulator of the cell cycle, to investigate the outcome of altered cell division on leaf physiology. Our approach involved combination of high-resolution microCT imaging and physiological analysis with a transient gene induction system, providing a powerful approach for the study of developmental physiology. Our investigation identifies a new role for RBR in mesophyll differentiation that affects tissue porosity and the distribution of air space within the leaf. The data demonstrate the importance of RBR in early leaf development and the extent to which physiology adapts to modified cellular architecture resulting from altered cell-cycle gene expression. PMID:24118480

Does mechanism matter? Unrelated neurotoxicants converge on cell cycle and apoptosis during neurodifferentiation.

PubMed

Slotkin, Theodore A; Seidler, Frederic J

2012-07-01

Mechanistically unrelated developmental neurotoxicants often produce neural cell loss culminating in similar functional and behavioral outcomes. We compared an organophosphate pesticide (diazinon), an organochlorine pesticide (dieldrin) and a metal (Ni(2+)) for effects on the genes regulating cell cycle and apoptosis in differentiating PC12 cells, an in vitro model of neuronal development. Each agent was introduced at 30μM for 24 or 72h, treatments devoid of cytotoxicity. Using microarrays, we examined the mRNAs encoding nearly 400 genes involved in each of the biological processes. All three agents targeted both the cell cycle and apoptosis pathways, evidenced by significant transcriptional changes in 40-45% of the cell cycle-related genes and 30-40% of the apoptosis-related genes. There was also a high degree of overlap as to which specific genes were affected by the diverse agents, with 80 cell cycle genes and 56 apoptosis genes common to all three. Concordance analysis, which assesses stringent matching of the direction, magnitude and timing of the transcriptional changes, showed highly significant correlations for pairwise comparisons of all the agents, for both cell cycle and apoptosis. Our results show that otherwise disparate developmental neurotoxicants converge on common cellular pathways governing the acquisition and programmed death of neural cells, providing a specific link to cell deficits. Our studies suggest that identifying the initial mechanism of action of a developmental neurotoxicant may be strategically less important than focusing on the pathways that converge on common final outcomes such as cell loss. Copyright © 2012 Elsevier Inc. All rights reserved.

DOES MECHANISM MATTER? UNRELATED NEUROTOXICANTS CONVERGE ON CELL CYCLE AND APOPTOSIS DURING NEURODIFFERENTIATION

PubMed Central

Slotkin, Theodore A.; Seidler, Frederic J.

2012-01-01

Mechanistically unrelated developmental neurotoxicants often produce neural cell loss culminating in similar functional and behavioral outcomes. We compared an organophosphate pesticide (diazinon), an organochlorine pesticide (dieldrin) and a metal (Ni2+) for effects on the genes regulating cell cycle and apoptosis in differentiating PC12 cells, an in vitro model of neuronal development. Each agent was introduced at 30 μM for 24 or 72 hr, treatments devoid of cytotoxicity. Using microarrays, we examined the mRNAs encoding nearly 400 genes involved in each of the biological processes. All three agents targeted both the cell cycle and apoptosis pathways, evidenced by significant transcriptional changes in 40–45% of the cell cycle-related genes and 30–40% of the apoptosis-related genes. There was also a high degree of overlap as to which specific genes were affected by the diverse agents, with 80 cell cycle genes and 56 apoptosis genes common to all three. Concordance analysis, which assesses stringent matching of the direction, magnitude and timing of the transcriptional changes, showed highly significant correlations for pairwise comparisons of all the agents, for both cell cycle and apoptosis. Our results show that otherwise disparate developmental neurotoxicants converge on common cellular pathways governing the acquisition and programmed death of neural cells, providing a specific link to cell deficits. Our studies suggest that identifying the initial mechanism of action of a developmental neurotoxicant may be strategically less important than focusing on the pathways that converge on common final outcomes such as cell loss. PMID:22546817

The AtRbx1 protein is part of plant SCF complexes, and its down-regulation causes severe growth and developmental defects.

PubMed

Lechner, Esther; Xie, Daoxin; Grava, Sandrine; Pigaglio, Emmanuelle; Planchais, Severine; Murray, James A H; Parmentier, Yves; Mutterer, Jerome; Dubreucq, Bertrand; Shen, Wen-Hui; Genschik, Pascal

2002-12-20

Recently in yeast and animal cells, one particular class of ubiquitin ligase (E3), called the SCF, was demonstrated to regulate diverse processes including cell cycle and development. In plants SCF-dependent proteolysis is also involved in different developmental and hormonal regulations. To further investigate the function of SCF, we characterized at the molecular level the Arabidopsis RING-H2 finger protein AtRbx1. We demonstrated that the plant gene is able to functionally complement a yeast knockout mutant strain and showed that AtRbx1 protein interacts physically with at least two members of the Arabidopsis cullin family (AtCul1 and AtCul4). AtRbx1 also associates with AtCul1 and the Arabidopsis SKP1-related proteins in planta, indicating that it is part of plant SCF complexes. AtRbx1 mRNAs accumulate in various tissues of the plant, but at higher levels in tissues containing actively dividing cells. Finally to study the function of the gene in planta, we either overexpressed AtRbx1 or reduced its expression by a dsRNA strategy. Down-regulation of AtRbx1 impaired seedling growth and development, indicating that the gene is essential in plants. Furthermore, the AtRbx1-silenced plants showed a reduced level of AtCul1 protein, but accumulated higher level of cyclin D3.

ASM Conference on Prokaryotic Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaplan, H. B.

2005-07-13

Support was provided by DOE for the 2nd ASM Conference on Prokaryotic Development. The final conference program and abstracts book is attached. The conference presentations are organized around topics that are central to the current research areas in prokaryotic development. The program starts with topics that involve relatively simple models systems and ends with systems that are more complex. The topics are: i) the cell cycle, ii) the cytoskeleton, iii) morphogenesis, iv) developmental transcription, v) signaling, vi) multicellularity, and vii) developmental diversity and symbiosis. The best-studied prokaryotic development model systems will be highlighted at the conference through research presentations bymore » leaders in the field. Many of these systems are also model systems of relevance to the DOE mission including carbon sequestration (Bradyrizobium, Synechococcus), energy production (Anabaena, Rhodobacter) and bioremediation (Caulobacter, Mesorhizobium). In addition, many of the highlighted organisms have important practical applications; the actinomycetes and myxobacteria produce antimicrobials that are of commercial interest. It is certain that the cutting-edge science presented at the conference will be applicable to the large group of bacteria relevant to the DOE mission.« less

Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research.

PubMed

Siciliano, Giulia; Alano, Pietro

2015-01-01

The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite P. berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.

A cell cycle-independent, conditional gene inactivation strategy for differentially tagging wild-type and mutant cells.

PubMed

Nagarkar-Jaiswal, Sonal; Manivannan, Sathiya N; Zuo, Zhongyuan; Bellen, Hugo J

2017-05-31

Here, we describe a novel method based on intronic MiMIC insertions described in Nagarkar-Jaiswal et al. (2015) to perform conditional gene inactivation in Drosophila . Mosaic analysis in Drosophila cannot be easily performed in post-mitotic cells. We therefore, therefore, developed Flip-Flop, a flippase -dependent in vivo cassette-inversion method that marks wild-type cells with the endogenous EGFP-tagged protein, whereas mutant cells are marked with mCherry upon inversion. We document the ease and usefulness of this strategy in differential tagging of wild-type and mutant cells in mosaics. We use this approach to phenotypically characterize the loss of SNF4Aγ , encoding the γ subunit of the AMP Kinase complex. The Flip-Flop method is efficient and reliable, and permits conditional gene inactivation based on both spatial and temporal cues, in a cell cycle-, and developmental stage-independent fashion, creating a platform for systematic screens of gene function in developing and adult flies with unprecedented detail.

Individual Meaning and Increasing Complexity: Contributions of Sigmund Freud and Rene Spitz to Developmental Psychology.

ERIC Educational Resources Information Center

Emde, Robert N.

1992-01-01

Considers contributions of Sigmund Freud and Rene Spitz to developmental psychology. Freud's contributions include his observations about play, perspectives on developmental processes, and ideas about unconscious mental activity. Spitz's contributions include his assessments of infants, perspectives on developmental processes, and his concept of…

The Theory behind the Theory in DCT and SCDT: A Response to Rigazio-DiGilio.

ERIC Educational Resources Information Center

Terry, Linda L.

1994-01-01

Responds to previous article by Rigazio-DiGilio on Developmental Counseling and Therapy and Systemic Cognitive-Developmental Therapy as two integrative models that unify individual, family, and network treatment within coconstructive-developmental framework. Discusses hidden complexities in cognitive-developmental ecosystemic integration and…

Mapping the developmental constraints on working memory span performance.

PubMed

Bayliss, Donna M; Jarrold, Christopher; Baddeley, Alan D; Gunn, Deborah M; Leigh, Eleanor

2005-07-01

This study investigated the constraints underlying developmental improvements in complex working memory span performance among 120 children of between 6 and 10 years of age. Independent measures of processing efficiency, storage capacity, rehearsal speed, and basic speed of processing were assessed to determine their contribution to age-related variance in complex span. Results showed that developmental improvements in complex span were driven by 2 age-related but separable factors: 1 associated with general speed of processing and 1 associated with storage ability. In addition, there was an age-related contribution shared between working memory, processing speed, and storage ability that was important for higher level cognition. These results pose a challenge for models of complex span performance that emphasize the importance of processing speed alone.

[Life-cycles, psychopathology and suicidal behaviour].

PubMed

Osváth, Péter

2012-12-01

According to modern psychological theories the human life implies continuous development, the efficient solution of age-specific problems is necessary to the successful transition of age-periods. The phases of transition are very vulnerable against the accidental stressors and negative life-events. Thus the problem-solving capacity may run out, which impairs chance of the successful coping with stressful events. It may result in some negative consequences, such as different psychopathological symptoms (depression, anxiety, psychosis) or even suicidal behaviour. For that reason we have to pay special attention to the symptoms of psychological crisis and the presuicidal syndrome. In certain life-cycle transitions (such as adolescent, middle or elderly age) the personality has special vulnerability to the development of psychological and psychopathological problems. In this article the most important features of life-cycles and psychopathological symptoms are reviewed. The developmental and age-specific characteristics have special importance in understanding the background of the actual psychological crisis and improving the efficacy of the treatment. Using the complex bio-psycho-socio-spiritual approach not only the actual psychopatological problems, but the individual psychological features can be recognised. Thus the effective treatment relieves not only the actual symptoms, but will increase the chance for solving further crises.

Translational Control in Plasmodium and Toxoplasma Parasites

PubMed Central

Joyce, Bradley R.; Sullivan, William J.; Nussenzweig, Victor

2013-01-01

The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis. PMID:23243065

Translational control in Plasmodium and toxoplasma parasites.

PubMed

Zhang, Min; Joyce, Bradley R; Sullivan, William J; Nussenzweig, Victor

2013-02-01

The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis.

Performance of children with developmental dyslexia on high and low topological entropy artificial grammar learning task.

PubMed

Katan, Pesia; Kahta, Shani; Sasson, Ayelet; Schiff, Rachel

2017-07-01

Graph complexity as measured by topological entropy has been previously shown to affect performance on artificial grammar learning tasks among typically developing children. The aim of this study was to examine the effect of graph complexity on implicit sequential learning among children with developmental dyslexia. Our goal was to determine whether children's performance depends on the complexity level of the grammar system learned. We conducted two artificial grammar learning experiments that compared performance of children with developmental dyslexia with that of age- and reading level-matched controls. Experiment 1 was a high topological entropy artificial grammar learning task that aimed to establish implicit learning phenomena in children with developmental dyslexia using previously published experimental conditions. Experiment 2 is a lower topological entropy variant of that task. Results indicated that given a high topological entropy grammar system, children with developmental dyslexia who were similar to the reading age-matched control group had substantial difficulty in performing the task as compared to typically developing children, who exhibited intact implicit learning of the grammar. On the other hand, when tested on a lower topological entropy grammar system, all groups performed above chance level, indicating that children with developmental dyslexia were able to identify rules from a given grammar system. The results reinforced the significance of graph complexity when experimenting with artificial grammar learning tasks, particularly with dyslexic participants.

Child and Adolescent Use of Mobile Phones: An Unparalleled Complex Developmental Phenomenon.

PubMed

Yan, Zheng

2018-01-01

This article addresses why children's use of mobile phones is an unparalleled complex developmental phenomenon in hopes of providing a broad context for this special section. It first outlines mobile phones as a sophisticated personalized and multifunction technology. Then it presents mobile phone use by children as an unparalleled complex developmental phenomenon on the basis of its four behavioral elements, two mobile cultures, and two developmental processes. It further illustrates the existing knowledge about children's mobile phones use that has been accumulated over the past 23 years and highlights 12 most studied topics, especially distracted driving and radiation exposure. It concludes with three types of scientific contributions made by the 12 articles in the special section. © 2017 The Author. Child Development © 2017 Society for Research in Child Development, Inc.

Heat-Treatment-Responsive Proteins in Different Developmental Stages of Tomato Pollen Detected by Targeted Mass Accuracy Precursor Alignment (tMAPA).

PubMed

Chaturvedi, Palak; Doerfler, Hannes; Jegadeesan, Sridharan; Ghatak, Arindam; Pressman, Etan; Castillejo, Maria Angeles; Wienkoop, Stefanie; Egelhofer, Volker; Firon, Nurit; Weckwerth, Wolfram

2015-11-06

Recently, we have developed a quantitative shotgun proteomics strategy called mass accuracy precursor alignment (MAPA). The MAPA algorithm uses high mass accuracy to bin mass-to-charge (m/z) ratios of precursor ions from LC-MS analyses, determines their intensities, and extracts a quantitative sample versus m/z ratio data alignment matrix from a multitude of samples. Here, we introduce a novel feature of this algorithm that allows the extraction and alignment of proteotypic peptide precursor ions or any other target peptide from complex shotgun proteomics data for accurate quantification of unique proteins. This strategy circumvents the problem of confusing the quantification of proteins due to indistinguishable protein isoforms by a typical shotgun proteomics approach. We applied this strategy to a comparison of control and heat-treated tomato pollen grains at two developmental stages, post-meiotic and mature. Pollen is a temperature-sensitive tissue involved in the reproductive cycle of plants and plays a major role in fruit setting and yield. By LC-MS-based shotgun proteomics, we identified more than 2000 proteins in total for all different tissues. By applying the targeted MAPA data-processing strategy, 51 unique proteins were identified as heat-treatment-responsive protein candidates. The potential function of the identified candidates in a specific developmental stage is discussed.

An Emerging Theoretical Model of Music Therapy Student Development.

PubMed

Dvorak, Abbey L; Hernandez-Ruiz, Eugenia; Jang, Sekyung; Kim, Borin; Joseph, Megan; Wells, Kori E

2017-07-01

Music therapy students negotiate a complex relationship with music and its use in clinical work throughout their education and training. This distinct, pervasive, and evolving relationship suggests a developmental process unique to music therapy. The purpose of this grounded theory study was to create a theoretical model of music therapy students' developmental process, beginning with a study within one large Midwestern university. Participants (N = 15) were music therapy students who completed one 60-minute intensive interview, followed by a 20-minute member check meeting. Recorded interviews were transcribed, analyzed, and coded using open and axial coding. The theoretical model that emerged was a six-step sequential developmental progression that included the following themes: (a) Personal Connection, (b) Turning Point, (c) Adjusting Relationship with Music, (d) Growth and Development, (e) Evolution, and (f) Empowerment. The first three steps are linear; development continues in a cyclical process among the last three steps. As the cycle continues, music therapy students continue to grow and develop their skills, leading to increased empowerment, and more specifically, increased self-efficacy and competence. Further exploration of the model is needed to inform educators' and other key stakeholders' understanding of student needs and concerns as they progress through music therapy degree programs. © the American Music Therapy Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Developmental regulation of CYCA2s contributes to tissue-specific proliferation in Arabidopsis

PubMed Central

Vanneste, Steffen; Coppens, Frederik; Lee, EunKyoung; Donner, Tyler J; Xie, Zidian; Van Isterdael, Gert; Dhondt, Stijn; De Winter, Freya; De Rybel, Bert; Vuylsteke, Marnik; De Veylder, Lieven; Friml, Jiří; Inzé, Dirk; Grotewold, Erich; Scarpella, Enrico; Sack, Fred; Beemster, Gerrit T S; Beeckman, Tom

2011-01-01

In multicellular organisms, morphogenesis relies on a strict coordination in time and space of cell proliferation and differentiation. In contrast to animals, plant development displays continuous organ formation and adaptive growth responses during their lifespan relying on a tight coordination of cell proliferation. How developmental signals interact with the plant cell-cycle machinery is largely unknown. Here, we characterize plant A2-type cyclins, a small gene family of mitotic cyclins, and show how they contribute to the fine-tuning of local proliferation during plant development. Moreover, the timely repression of CYCA2;3 expression in newly formed guard cells is shown to require the stomatal transcription factors FOUR LIPS/MYB124 and MYB88, providing a direct link between developmental programming and cell-cycle exit in plants. Thus, transcriptional downregulation of CYCA2s represents a critical mechanism to coordinate proliferation during plant development. PMID:21772250

Sub-lethal and lethal toxicities of elevated CO2 on embryonic, juvenile, and adult stages of marine medaka Oryzias melastigma.

PubMed

Lee, Changkeun; Kwon, Bong-Oh; Hong, Seongjin; Noh, Junsung; Lee, Junghyun; Ryu, Jongseong; Kang, Seong-Gil; Khim, Jong Seong

2018-06-06

The potential leakage from marine CO 2 storage sites is of increasing concern, but few studies have evaluated the probable adverse effects on marine organisms. Fish, one of the top predators in marine environments, should be an essential representative species used for water column toxicity testing in response to waterborne CO 2 exposure. In the present study, we conducted fish life cycle toxicity tests to fully elucidate CO 2 toxicity mechanism effects. We tested sub-lethal and lethal toxicities of elevated CO 2 concentrations on marine medaka (Oryzias melastigma) at different developmental stages. At each developmental stage, the test species was exposed to varying concentrations of gaseous CO 2 (control air, 5%, 10%, 20%, and 30%), with 96 h of exposure at 0-4 d (early stage), 4-8 d (middle stage), and 8-12 d (late stage). Sub-lethal and lethal effects, including early developmental delays, cardiac edema, tail abnormalities, abnormal pigmentation, and mortality were monitored daily during the 14 d exposure period. At the embryonic stage, significant sub-lethal and lethal effects were observed at pH < 6.30. Hypercapnia can cause long-term and/or delayed developmental embryonic problems, even after transfer back to clean seawater. At fish juvenile and adult stages, significant mortality was observed at pH < 5.70, indicating elevated CO 2 exposure might cause various adverse effects, even during short-term exposure periods. It should be noted the early embryonic stage was found more sensitive to CO 2 exposure than other developmental stages of the fish life cycle. Overall, the present study provided baseline information for potential adverse effects of high CO 2 concentration exposure on fish developmental processes at different life cycle stages in marine ecosystems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Insect seasonality: circle map analysis of temperature-driven life cycles.

PubMed

Powell, James A; Logan, Jesse A

2005-05-01

Maintaining an adaptive seasonality, with life cycle events occurring at appropriate times of year and in synchrony with cohorts and ephemeral resources, is a basic ecological requisite for many cold-blooded organisms. There are many mechanisms for synchronizing developmental milestones, such as egg laying (oviposition), egg hatching, cocoon opening, and the emergence of adults. These are often irreversible, specific to particular life stages, and include diapause, an altered physiological state which can be reversed by some synchronizing environmental cue (e.g. photoperiod). However, many successful organisms display none of these mechanisms for maintaining adaptive seasonality. In this paper, we briefly review the mathematical relationship between environmental temperatures and developmental timing and discuss the consequences of viewing these models as circle maps from the cycle of yearly oviposition dates and temperatures to oviposition dates for subsequent generations. Of particular interest biologically are life cycles which are timed to complete in exactly 1 year, or univoltine cycles. Univoltinism, associated with reproductive success for many temperate species, is related to stable fixed points of the developmental circle map. Univoltine fixed points are stable and robust in broad temperature bands, but lose stability suddenly to maladaptive cycles at the edges of these bands. Adaptive seasonality may therefore break down with little warning with constantly increasing or decreasing temperature change, as in scenarios for global warming. These ideas are illustrated and explored in the context of Mountain Pine Beetle (Dendroctonus ponderosae Hopkins) occurring in the marginal thermal habitat of central Idaho's Rocky Mountains. Applications of these techniques have not been widely explored by the applied math community, but are likely to provide great insight into the response of biological systems to climate change.

Metabolomics approach reveals metabolic disorders and potential biomarkers associated with the developmental toxicity of tetrabromobisphenol A and tetrachlorobisphenol A

NASA Astrophysics Data System (ADS)

Ye, Guozhu; Chen, Yajie; Wang, Hong-Ou; Ye, Ting; Lin, Yi; Huang, Qiansheng; Chi, Yulang; Dong, Sijun

2016-10-01

Tetrabromobisphenol A and tetrachlorobisphenol A are halogenated bisphenol A (H-BPA), and has raised concerns about their adverse effects on the development of fetuses and infants, however, the molecular mechanisms are unclear, and related metabolomics studies are limited. Accordingly, a metabolomics study based on gas chromatography-mass spectrometry was employed to elucidate the molecular developmental toxicology of H-BPA using the marine medaka (Oryzias melastigmas) embryo model. Here, we revealed decreased synthesis of nucleosides, amino acids and lipids, and disruptions in the TCA (tricarboxylic acid) cycle, glycolysis and lipid metabolism, thus inhibiting the developmental processes of embryos exposed to H-BPA. Unexpectedly, we observed enhanced neural activity accompanied by lactate accumulation and accelerated heart rates due to an increase in dopamine pathway and a decrease in inhibitory neurotransmitters following H-BPA exposure. Notably, disorders of the neural system, and disruptions in glycolysis, the TCA cycle, nucleoside metabolism, lipid metabolism, glutamate and aspartate metabolism induced by H-BPA exposure were heritable. Furthermore, lactate and dopa were identified as potential biomarkers of the developmental toxicity of H-BPA and related genetic effects. This study has demonstrated that the metabolomics approach is a useful tool for obtaining comprehensive and novel insights into the molecular developmental toxicity of environmental pollutants.

Bombyx mori cyclin-dependent kinase inhibitor is involved in regulation of the silkworm cell cycle.

PubMed

Tang, X-F; Zhou, X-L; Zhang, Q; Chen, P; Lu, C; Pan, M-H

2018-06-01

Cyclin-dependent kinase inhibitors (CKIs) are negative regulators of the cell cycle. They can bind to cyclin-dependent kinase (CDK)-cyclin complexes and inhibit CDK activities. We identified a single homologous gene of the CDK interacting protein/kinase inhibitory protein (Cip/Kip) family, BmCKI, in the silkworm, Bombyx mori. The gene transcribes two splice variants: a 654-bp-long BmCKI-L (the longer splice variant) encoding a protein with 217 amino acids and a 579-bp-long BmCKI-S (the shorter splice variant) encoding a protein with 192 amino acids. BmCKI-L and BmCKI-S contain the Cip/Kip family conserved cyclin-binding domain and the CDK-binding domain. They are localized in the nucleus and have an unconventional bipartite nuclear localization signal at amino acid residues 181-210. Overexpression of BmCKI-L or BmCKI-S affected cell cycle progression; the cell cycle was arrested in the first gap phase of cell cycle (G1). RNA interference of BmCKI-L or BmCKI-S led to cells accumulating in the second gap phase and the mitotic phase of cell cycle (G2/M). Both BmCKI-L and BmCKI-S are involved in cell cycle regulation and probably have similar effects. The transgenic silkworm with BmCKI-L overexpression (BmCKI-L-OE), exhibited embryonic lethal, larva developmental retardation and lethal phenotypes. These results suggest that BmCKI-L might regulate the growth and development of silkworm. These findings clarify the function of CKIs and increase our understanding of cell cycle regulation in the silkworm. © 2018 The Royal Entomological Society.

Mutations in ORC1, encoding the largest subunit of the origin recognition complex, cause microcephalic primordial dwarfism resembling Meier-Gorlin syndrome.

PubMed

Bicknell, Louise S; Walker, Sarah; Klingseisen, Anna; Stiff, Tom; Leitch, Andrea; Kerzendorfer, Claudia; Martin, Carol-Anne; Yeyati, Patricia; Al Sanna, Nouriya; Bober, Michael; Johnson, Diana; Wise, Carol; Jackson, Andrew P; O'Driscoll, Mark; Jeggo, Penny A

2011-02-27

Studies into disorders of extreme growth failure (for example, Seckel syndrome and Majewski osteodysplastic primordial dwarfism type II) have implicated fundamental cellular processes of DNA damage response signaling and centrosome function in the regulation of human growth. Here we report that mutations in ORC1, encoding a subunit of the origin recognition complex, cause microcephalic primordial dwarfism resembling Meier-Gorlin syndrome. We establish that these mutations disrupt known ORC1 functions including pre-replicative complex formation and origin activation. ORC1 deficiency perturbs S-phase entry and S-phase progression. Additionally, we show that Orc1 depletion in zebrafish is sufficient to markedly reduce body size during rapid embryonic growth. Our data suggest a model in which ORC1 mutations impair replication licensing, slowing cell cycle progression and consequently impeding growth during development, particularly at times of rapid proliferation. These findings establish a novel mechanism for the pathogenesis of microcephalic dwarfism and show a surprising but important developmental impact of impaired origin licensing.

How Polycomb-Mediated Cell Memory Deals With a Changing Environment: Variations in PcG complexes and proteins assortment convey plasticity to epigenetic regulation as a response to environment.

PubMed

Marasca, Federica; Bodega, Beatrice; Orlando, Valerio

2018-04-01

Cells and tissues are continuously exposed to a changing microenvironment, hence the necessity of a flexible modulation of gene expression that in complex organism have been achieved through specialized chromatin mechanisms. Chromatin-based cell memory enables cells to maintain their identity by fixing lineage specific transcriptional programs, ensuring their faithful transmission through cell division; in particular PcG-based memory system evolved to maintain the silenced state of developmental and cell cycle genes. In evolution the complexity of this system have increased, particularly in vertebrates, indicating combinatorial and dynamic properties of Polycomb proteins, in some cases even overflowing outside the cell nucleus. Therefore, their function may not be limited to the imposition of rigid states of genetic programs, but on the ability to recognize signals and allow plastic transcriptional changes in response to different stimuli. Here, we discuss the most novel PcG mediated memory functions in facing and responding to the challenges posed by a fluctuating environment. © 2018 The Authors. BioEssays Published by WILEY Periodicals, Inc.

The Complexity of Developmental Predictions from Dual Process Models

ERIC Educational Resources Information Center

Stanovich, Keith E.; West, Richard F.; Toplak, Maggie E.

2011-01-01

Drawing developmental predictions from dual-process theories is more complex than is commonly realized. Overly simplified predictions drawn from such models may lead to premature rejection of the dual process approach as one of many tools for understanding cognitive development. Misleading predictions can be avoided by paying attention to several…

Developmental Evaluation: Applying Complexity Concepts to Enhance Innovation and Use

ERIC Educational Resources Information Center

Patton, Michael Quinn

2010-01-01

Developmental evaluation (DE) offers a powerful approach to monitoring and supporting social innovations by working in partnership with program decision makers. In this book, eminent authority shows how to conduct evaluations within a DE framework. Patton draws on insights about complex dynamic systems, uncertainty, nonlinearity, and emergence. He…

Understanding growth and development of forage plants

USDA-ARS?s Scientific Manuscript database

Understanding the developmental morphology of forage plants is important for making good management decisions. Many such decisions involve timing the initiation or termination of a management practice to a particular stage of development in the life cycle of the forage. The life cycles of forage pl...

Cycles of Research and Application in Education: Learning Pathways for Energy Concepts

ERIC Educational Resources Information Center

Dawson, Theo L.; Stein, Zachary

2008-01-01

We begin this article by situating a methodology called "developmental maieutics" in the emerging field of mind, brain, and education. Then, we describe aspects of a project in which we collaborated with a group of physical science teachers to design developmentally informed activities and assessments for a unit on energy. Pen-and-paper…

Caenorhabditis elegans Pheromones Regulate Multiple Complex Behaviors

PubMed Central

Edison, Arthur S.

2009-01-01

Summary of recent advances A family of small molecules called ascarosides act as pheromones to control multiple behaviors in the nematode Caenorhabditis elegans. At picomolar concentrations, a synergistic mixture of at least three ascarosides produced by hermaphrodites causes male-specific attraction. At higher concentrations, the same ascarosides, perhaps in a different mixture, induce the developmentally arrested stage known as dauer. The production of ascarosides is strongly dependent on environmental conditions, although relatively little is known about the major variables and mechanisms of their regulation. Thus, male mating and dauer formation are linked through a common set of small molecules whose expression is sensitive to a given microenvironment, suggesting a model by which ascarosides regulate the overall life cycle of C. elegans. PMID:19665885

Regulation of the Embryonic Cell Cycle During Mammalian Preimplantation Development.

PubMed

Palmer, N; Kaldis, P

2016-01-01

The preimplantation development stage of mammalian embryogenesis consists of a series of highly conserved, regulated, and predictable cell divisions. This process is essential to allow the rapid expansion and differentiation of a single-cell zygote into a multicellular blastocyst containing cells of multiple developmental lineages. This period of development, also known as the germinal stage, encompasses several important developmental transitions, which are accompanied by dramatic changes in cell cycle profiles and dynamics. These changes are driven primarily by differences in the establishment and enforcement of cell cycle checkpoints, which must be bypassed to facilitate the completion of essential cell cycle events. Much of the current knowledge in this area has been amassed through the study of knockout models in mice. These mouse models are powerful experimental tools, which have allowed us to dissect the relative dependence of the early embryonic cell cycles on various aspects of the cell cycle machinery and highlight the extent of functional redundancy between members of the same gene family. This chapter will explore the ways in which the cell cycle machinery, their accessory proteins, and their stimuli operate during mammalian preimplantation using mouse models as a reference and how this allows for the usually well-defined stages of the cell cycle to be shaped and transformed during this unique and critical stage of development. © 2016 Elsevier Inc. All rights reserved.

The Life Cycle of Images: Revisiting the Ethical Treatment of the Art Therapy Image

ERIC Educational Resources Information Center

Hinz, Lisa D.

2013-01-01

Using the metaphor of the human life cycle, the author of this viewpoint suggests that consideration of the birth, life, and death of images made in art therapy may promote a new perspective on their ethical treatment. A developmental view of images encourages art therapists to see art images as living entities that undergo a natural life cycle.…

Crystal Structure of the Eukaryotic Origin Recognition Complex

PubMed Central

Bleichert, Franziska; Botchan, Michael R.; Berger, James M.

2015-01-01

Initiation of cellular DNA replication is tightly controlled to sustain genomic integrity. In eukaryotes, the heterohexameric origin recognition complex (ORC) is essential for coordinating replication onset. The 3.5 Å resolution crystal structure of Drosophila ORC reveals that the 270 kDa initiator core complex comprises a two-layered notched ring in which a collar of winged-helix domains from the Orc1-5 subunits sits atop a layer of AAA+ ATPase folds. Although canonical inter-AAA+ domain interactions exist between four of the six ORC subunits, unanticipated features are also evident, including highly interdigitated domain-swapping interactions between the winged-helix folds and AAA+ modules of neighboring protomers, and a quasi-spiral arrangement of DNA binding elements that circumnavigate a ~20 Å wide channel in the center of the complex. Comparative analyses indicate that ORC encircles DNA, using its winged-helix domain face to engage the MCM2-7 complex during replicative helicase loading; however, an observed >90° out-of-plane rotation for the Orc1 AAA+ domain disrupts interactions with catalytic amino acids in Orc4, narrowing and sealing off entry into the central channel. Prima facie, our data indicate that Drosophila ORC can switch between active and autoinhibited conformations, suggesting a novel means for cell cycle and/or developmental control of ORC functions. PMID:25762138

The Developmental Process of Clinical Supervisors in Training: An Investigation of the Supervisor Complexity Model.

ERIC Educational Resources Information Center

Baker, Stanley B.; Exum, Herbert A.; Tyler, Richard E.

2002-01-01

Investigates the supervisor complexity model (SCM) using the Psychotherapy Supervisor Development Scale (PSDS) to ascertain development over a 15-week supervision practicum for 12 doctoral students. A set of retrospective interview questions produced responses used to investigate the viability of the 4 proposed discrete developmental stages in the…

Succinate Dehydrogenase Mutation Underlies Global Epigenomic Divergence in Gastrointestinal Stromal Tumor

PubMed Central

Killian, J. Keith; Kim, Su Young; Miettinen, Markku; Smith, Carly; Merino, Maria; Tsokos, Maria; Quezado, Martha; Smith, William I.; Jahromi, Mona S.; Xekouki, Paraskevi; Szarek, Eva; Walker, Robert L.; Lasota, Jerzy; Raffeld, Mark; Klotzle, Brandy; Wang, Zengfeng; Jones, Laura; Zhu, Yuelin; Wang, Yonghong; Waterfall, Joshua J.; O’Sullivan, Maureen J.; Bibikova, Marina; Pacak, Karel; Stratakis, Constantine; Janeway, Katherine A.; Schiffman, Joshua D.; Fan, Jian-Bing; Helman, Lee; Meltzer, Paul S.

2014-01-01

Gastrointestinal stromal tumors (GIST) harbor driver mutations of signal transduction kinases such as KIT, or, alternatively, manifest loss-of-function defects in the mitochondrial succinate dehydrogenase (SDH) complex, a component of the Krebs cycle and electron transport chain. We have uncovered a striking divergence between the DNA methylation profiles of SDH-deficient GIST (n = 24) versus KIT tyrosine kinase pathway–mutated GIST (n = 39). Infinium 450K methylation array analysis of formalin-fixed paraffin-embedded tissues disclosed an order of magnitude greater genomic hypermethylation relative to SDH-deficient GIST versus the KIT-mutant group (84.9 K vs. 8.4 K targets). Epigenomic divergence was further found among SDH-mutant paraganglioma/pheochromocytoma (n = 29), a developmentally distinct SDH-deficient tumor system. Comparison of SDH -mutant GIST with isocitrate dehydrogenase -mutant glioma, another Krebs cycle–defective tumor type, revealed comparable measures of global hypo- and hypermethylation. These data expose a vital connection between succinate metabolism and genomic DNA methylation during tumorigenesis, and generally implicate the mitochondrial Krebs cycle in nuclear epigenomic maintenance. SIGNIFICANCE This study shows that SDH deficiency underlies pervasive DNA hypermethylation in multiple tumor lineages, generally defining the Krebs cycle as mitochondrial custodian of the methylome. We propose that this phenomenon may result from a failure of maintenance CpG demethylation, secondary to inhibition of the TET 5-methylcytosine dioxgenase demethylation pathway, by inhibitory metabolites that accumulate in tumors with Krebs cycle dysfunction. PMID:23550148

Development of Civic Engagement: Theoretical and Methodological Issues

ERIC Educational Resources Information Center

Lerner, Richard M.; Wang, Jun; Champine, Robey B.; Warren, Daniel J. A.; Erickson, Karl

2014-01-01

Within contemporary developmental science, models derived from relational developmental systems (RDS) metatheory emphasize that the basic process of human development involves mutually-influential relations, termed developmental regulations, between the developing individual and his or her complex and changing physical, social, and cultural…

Metacognition in speech and language therapy for children with social (pragmatic) communication disorders: implications for a theory of therapy.

PubMed

Gaile, Jacqueline; Adams, Catherine

2018-01-01

Metacognition is a significant component of complex interventions for children who have developmental language disorders. Research into how metacognition operates in the content or process of developmental language therapy delivery is limited. Identification and description of proposed active therapy components, such as metacognition, may contribute to our understanding of how to deliver complex communication interventions in an optimal manner. To analyse aspects of metacognition during therapy derived from a manualized speech and language intervention (the Social Communication Intervention Programme-SCIP) as delivered to children who have social (pragmatic) communication disorder (SPCD) and to examine the dynamic process of delivering therapy. A purposive sample of eight filmed therapy sessions was selected from the video data corpus of intervention-arm participants within a randomized controlled trial. The child-therapist interactions during therapy sessions from five children (aged between 5;11 and 10;3) in the SCIP trial were transcribed. Filmed sessions represented a variety of communication profiles and SCIP therapy content. Starting from existing theory on metacognition, cycles of iterative analysis were performed using a mixed inductive-deductive qualitative analysis. A preliminary list of metacognitive content embedded in the intervention was developed into a metacognitive coding framework (MCF). A thematic analysis of the identified metacognitive content of the intervention was then carried out across the whole sample. Thematic analysis revealed the presence of metacognition in the content and delivery of SCIP intervention. Four main themes of metacognitive person, task and strategy knowledge, and monitoring/control were identified. Metacognition was a feature of how children's ability to monitor language, pragmatic and social interaction skills, in themselves and other people, was developed. Task design and delivery methods were found to play a particular role in adjusting the metacognitive content of the therapy activities. This study makes explicit the metacognitive content and delivery within a complex developmental communication intervention. Discussion of the findings about metacognitive content provides an explanation of how the skilled speech and language therapist manipulates task demands, person knowledge and therapy methods towards the therapy goal. Clinical applications of the metacognitive framework are discussed. We suggest that the process of making the tacit knowledge of the therapist explicit can contribute to the implementation of complex evidence-based interventions. © 2017 Royal College of Speech and Language Therapists.

Life cycle expression analysis of three cell wall degradation-related genes in ethylene-treated grass

USDA-ARS?s Scientific Manuscript database

Ethylene regulates multiple developmental processes during a plant life cycle, but the effect of ethylene on the upregulation of senescence-, stress-, and post-harvest-related genes in forage grasses is poorly understood. In this work, we used quantitative PCR to determine whether ethylene applicat...

Retinal dystrophies, genomic applications in diagnosis and prospects for therapy

PubMed Central

Nash, Benjamin M.; Wright, Dale C.; Grigg, John R.; Bennetts, Bruce

2015-01-01

Retinal dystrophies (RDs) are degenerative diseases of the retina which have marked clinical and genetic heterogeneity. Common presentations among these disorders include night or colour blindness, tunnel vision and subsequent progression to complete blindness. The known causative disease genes have a variety of developmental and functional roles with mutations in more than 120 genes shown to be responsible for the phenotypes. In addition, mutations within the same gene have been shown to cause different disease phenotypes, even amongst affected individuals within the same family highlighting further levels of complexity. The known disease genes encode proteins involved in retinal cellular structures, phototransduction, the visual cycle, and photoreceptor structure or gene regulation. This review aims to demonstrate the high degree of genetic complexity in both the causative disease genes and their associated phenotypes, highlighting the more common clinical manifestation of retinitis pigmentosa (RP). The review also provides insight to recent advances in genomic molecular diagnosis and gene and cell-based therapies for the RDs. PMID:26835369

Electron tomography and cryo-SEM characterization reveals novel ultrastructural features of host-parasite interaction during Chlamydia abortus infection.

PubMed

Wilkat, M; Herdoiza, E; Forsbach-Birk, V; Walther, P; Essig, A

2014-08-01

Chlamydia (C.) abortus is a widely spread pathogen among ruminants that can be transmitted to women during pregnancy leading to severe systemic infection with consecutive abortion. As a member of the Chlamydiaceae, C. abortus shares the characteristic feature of an obligate intracellular biphasic developmental cycle with two morphological forms including elementary bodies (EBs) and reticulate bodies (RBs). In contrast to other chlamydial species, C. abortus ultrastructure has not been investigated yet. To do so, samples were fixed by high-pressure freezing and processed by different electron microscopic methods. Freeze-substituted samples were analysed by transmission electron microscopy, scanning transmission electron microscopical tomography and immuno-electron microscopy, and freeze-fractured samples were analysed by cryo-scanning electron microscopy. Here, we present three ultrastructural features of C. abortus that have not been reported up to now. Firstly, the morphological evidence that C. abortus is equipped with the type three secretion system. Secondly, the accumulation and even coating of whole inclusion bodies by membrane complexes consisting of multiple closely adjacent membranes which seems to be a C. abortus specific feature. Thirdly, the formation of small vesicles in the periplasmic space of RBs in the second half of the developmental cycle. Concerning the time point of their formation and the fact that they harbour chlamydial components, these vesicles might be morphological correlates of an intermediate step during the process of redifferentiation of RBs into EBs. As this feature has also been shown for C. trachomatis and C. pneumoniae, it might be a common characteristic of the family of Chlamydiaceae.

Mechanisms of animal diapause: recent developments from nematodes, crustaceans, insects, and fish

PubMed Central

Denlinger, David L.; Podrabsky, Jason E.; Roy, Richard

2016-01-01

Life cycle delays are beneficial for opportunistic species encountering suboptimal environments. Many animals display a programmed arrest of development (diapause) at some stage(s) of their development, and the diapause state may or may not be associated with some degree of metabolic depression. In this review, we will evaluate current advancements in our understanding of the mechanisms responsible for the remarkable phenotype, as well as environmental cues that signal entry and termination of the state. The developmental stage at which diapause occurs dictates and constrains the mechanisms governing diapause. Considerable progress has been made in clarifying proximal mechanisms of metabolic arrest and the signaling pathways like insulin/Foxo that control gene expression patterns. Overlapping themes are also seen in mechanisms that control cell cycle arrest. Evidence is emerging for epigenetic contributions to diapause regulation via small RNAs in nematodes, crustaceans, insects, and fish. Knockdown of circadian clock genes in selected insect species supports the importance of clock genes in the photoperiodic response that cues diapause. A large suite of chaperone-like proteins, expressed during diapause, protects biological structures during long periods of energy-limited stasis. More information is needed to paint a complete picture of how environmental cues are coupled to the signal transduction that initiates the complex diapause phenotype, as well as molecular explanations for how the state is terminated. Excellent examples of molecular memory in post-dauer animals have been documented in Caenorhabditis elegans. It is clear that a single suite of mechanisms does not regulate diapause across all species and developmental stages. PMID:27053646

Mechanisms of animal diapause: recent developments from nematodes, crustaceans, insects, and fish.

PubMed

Hand, Steven C; Denlinger, David L; Podrabsky, Jason E; Roy, Richard

2016-06-01

Life cycle delays are beneficial for opportunistic species encountering suboptimal environments. Many animals display a programmed arrest of development (diapause) at some stage(s) of their development, and the diapause state may or may not be associated with some degree of metabolic depression. In this review, we will evaluate current advancements in our understanding of the mechanisms responsible for the remarkable phenotype, as well as environmental cues that signal entry and termination of the state. The developmental stage at which diapause occurs dictates and constrains the mechanisms governing diapause. Considerable progress has been made in clarifying proximal mechanisms of metabolic arrest and the signaling pathways like insulin/Foxo that control gene expression patterns. Overlapping themes are also seen in mechanisms that control cell cycle arrest. Evidence is emerging for epigenetic contributions to diapause regulation via small RNAs in nematodes, crustaceans, insects, and fish. Knockdown of circadian clock genes in selected insect species supports the importance of clock genes in the photoperiodic response that cues diapause. A large suite of chaperone-like proteins, expressed during diapause, protects biological structures during long periods of energy-limited stasis. More information is needed to paint a complete picture of how environmental cues are coupled to the signal transduction that initiates the complex diapause phenotype, as well as molecular explanations for how the state is terminated. Excellent examples of molecular memory in post-dauer animals have been documented in Caenorhabditis elegans It is clear that a single suite of mechanisms does not regulate diapause across all species and developmental stages. Copyright © 2016 the American Physiological Society.

Developmental constraints in cave beetles

PubMed Central

Cieslak, Alexandra; Fresneda, Javier; Ribera, Ignacio

2014-01-01

In insects, whilst variations in life cycles are common, the basic patterns typical for particular groups remain generally conserved. One of the more extreme modifications is found in some subterranean beetles of the tribe Leptodirini, in which the number of larval instars is reduced from the ancestral three to two and ultimately one, which is not active and does not feed. We analysed all available data on the duration and size of the different developmental stages and compared them in a phylogenetic context. The total duration of development was found to be strongly conserved, irrespective of geographical location, habitat type, number of instars and feeding behaviour of the larvae, with a single alteration of the developmental pattern in a clade of cave species in southeast France. We also found a strong correlation of the size of the first instar larva with adult size, again regardless of geographical location, ecology and type of life cycle. Both results suggest the presence of deeply conserved constraints in the timing and energy requirements of larval development. Past focus on more apparent changes, such as the number of larval instars, may mask more deeply conserved ontogenetic patterns in developmental timing. PMID:25354919

Contemplative Practices and Orders of Consciousness: A Constructive-Developmental Approach

ERIC Educational Resources Information Center

Silverstein, Charles H.

2012-01-01

This qualitative study explores the correspondence between contemplative practices and "orders of consciousness" from a constructive-developmental perspective, using Robert Kegan's approach. Adult developmental growth is becoming an increasingly important influence on humanity's ability to deal effectively with the growing complexity of…

Ovary transcriptome profiling via artificial intelligence reveals a transcriptomic fingerprint predicting egg quality in striped bass, Morone saxatilis.

PubMed

Chapman, Robert W; Reading, Benjamin J; Sullivan, Craig V

2014-01-01

Inherited gene transcripts deposited in oocytes direct early embryonic development in all vertebrates, but transcript profiles indicative of embryo developmental competence have not previously been identified. We employed artificial intelligence to model profiles of maternal ovary gene expression and their relationship to egg quality, evaluated as production of viable mid-blastula stage embryos, in the striped bass (Morone saxatilis), a farmed species with serious egg quality problems. In models developed using artificial neural networks (ANNs) and supervised machine learning, collective changes in the expression of a limited suite of genes (233) representing <2% of the queried ovary transcriptome explained >90% of the eventual variance in embryo survival. Egg quality related to minor changes in gene expression (<0.2-fold), with most individual transcripts making a small contribution (<1%) to the overall prediction of egg quality. These findings indicate that the predictive power of the transcriptome as regards egg quality resides not in levels of individual genes, but rather in the collective, coordinated expression of a suite of transcripts constituting a transcriptomic "fingerprint". Correlation analyses of the corresponding candidate genes indicated that dysfunction of the ubiquitin-26S proteasome, COP9 signalosome, and subsequent control of the cell cycle engenders embryonic developmental incompetence. The affected gene networks are centrally involved in regulation of early development in all vertebrates, including humans. By assessing collective levels of the relevant ovarian transcripts via ANNs we were able, for the first time in any vertebrate, to accurately predict the subsequent embryo developmental potential of eggs from individual females. Our results show that the transcriptomic fingerprint evidencing developmental dysfunction is highly predictive of, and therefore likely to regulate, egg quality, a biologically complex trait crucial to reproductive fitness.

Ovary Transcriptome Profiling via Artificial Intelligence Reveals a Transcriptomic Fingerprint Predicting Egg Quality in Striped Bass, Morone saxatilis

PubMed Central

2014-01-01

Inherited gene transcripts deposited in oocytes direct early embryonic development in all vertebrates, but transcript profiles indicative of embryo developmental competence have not previously been identified. We employed artificial intelligence to model profiles of maternal ovary gene expression and their relationship to egg quality, evaluated as production of viable mid-blastula stage embryos, in the striped bass (Morone saxatilis), a farmed species with serious egg quality problems. In models developed using artificial neural networks (ANNs) and supervised machine learning, collective changes in the expression of a limited suite of genes (233) representing <2% of the queried ovary transcriptome explained >90% of the eventual variance in embryo survival. Egg quality related to minor changes in gene expression (<0.2-fold), with most individual transcripts making a small contribution (<1%) to the overall prediction of egg quality. These findings indicate that the predictive power of the transcriptome as regards egg quality resides not in levels of individual genes, but rather in the collective, coordinated expression of a suite of transcripts constituting a transcriptomic “fingerprint”. Correlation analyses of the corresponding candidate genes indicated that dysfunction of the ubiquitin-26S proteasome, COP9 signalosome, and subsequent control of the cell cycle engenders embryonic developmental incompetence. The affected gene networks are centrally involved in regulation of early development in all vertebrates, including humans. By assessing collective levels of the relevant ovarian transcripts via ANNs we were able, for the first time in any vertebrate, to accurately predict the subsequent embryo developmental potential of eggs from individual females. Our results show that the transcriptomic fingerprint evidencing developmental dysfunction is highly predictive of, and therefore likely to regulate, egg quality, a biologically complex trait crucial to reproductive fitness. PMID:24820964

A Rhodium(III) Complex as an Inhibitor of Neural Precursor Cell Expressed, Developmentally Down-Regulated 8-Activating Enzyme with in Vivo Activity against Inflammatory Bowel Disease.

PubMed

Zhong, Hai-Jing; Wang, Wanhe; Kang, Tian-Shu; Yan, Hui; Yang, Yali; Xu, Lipeng; Wang, Yuqiang; Ma, Dik-Lung; Leung, Chung-Hang

2017-01-12

We report herein the identification of the rhodium(III) complex [Rh(phq) 2 (MOPIP)] + (1) as a potent and selective ATP-competitive neural precursor cell expressed, developmentally down-regulated 8 (NEDD8)-activating enzyme (NAE) inhibitor. Structure-activity relationship analysis indicated that the overall organometallic design of complex 1 was important for anti-inflammatory activity. Complex 1 showed promising anti-inflammatory activity in vivo for the potential treatment of inflammatory bowel disease.

Mammalian Homologs of Yeast Checkpoint Genes

DTIC Science & Technology

2002-07-01

pathway is sensitive to various forms of DNA damage Developmental Biology throughout the cell cycle . The DNA replication check- Yale University point...components would be ordered into pathways for mammalian checkpoint function, with emphasis on p53 regulation, cell cycle regulation, and complementation...structurally related to the human tumor suppressor ATM. MEC1 and RAD53, two essential genes, play a central role in DNA damage checkpoints at all cell cycle

Public health approaches to safer cycling for children based on developmental and physiological readiness: implications for practice

PubMed Central

Lenton, Simon; Finlay, Fiona Olwen

2018-01-01

Introduction Cyclists have a high mortality and morbidity per mile travelled compared with car occupants, a figure that is likely to increase if campaigns to increase active travel are successful. Concerns about safety is the leading factor limiting cycling for children. Objective This review brings together a paediatric perspective based on the developmental readiness of children and young people and a public health approach to reducing injuries, to produce a practical agenda for improving the safety of cycling for children. Method Selective literature review. Results While most sports realise the importance of practice and training to create mastery of the game, similar thinking has not been consistently applied to cycling proficiency, so many children do not have an opportunity to master cycling before riding on the roads. Conclusions The aim should be to minimise road traffic injuries involving children and young people in ways that create cobenefits for other members of society, increasing opportunities for active travel, reducing air pollution, creating more green space to play and reducing dependence on motor vehicles. Changes in legislation are required now to enable younger children to cycle on pavements while learning to ride and improvements in road design to separate cyclists from motor vehicles especially routes to school for older children. PMID:29637180

Performance of Children with Developmental Dyslexia on High and Low Topological Entropy Artificial Grammar Learning Task

ERIC Educational Resources Information Center

Katan, Pesia; Kahta, Shani; Sasson, Ayelet; Schiff, Rachel

2017-01-01

Graph complexity as measured by topological entropy has been previously shown to affect performance on artificial grammar learning tasks among typically developing children. The aim of this study was to examine the effect of graph complexity on implicit sequential learning among children with developmental dyslexia. Our goal was to determine…

Interaction of Social and Play Behaviors in Preschoolers With and Without Pervasive Developmental Disorder

ERIC Educational Resources Information Center

Pierce-Jordan, Sandra; Lifter, Karin

2005-01-01

This study investigated the relationship between the social and play behaviors of young children with pervasive developmental disorder (PDD) and without PDD. Videotaped observations of 21 preschool children (12 with PDD and 9 without PDD) were examined independently for (a) social complexity and (b) play complexity that was assessed on an…

Developmental instability of gynodioecious Teucrium lusitanicum

USGS Publications Warehouse

Alados, C.L.; Navarro, T.; Cabezudo, B.; Emlen, J.M.; Freeman, C.

1998-01-01

Developmental instability was assessed in two geographical races of Teucrium lusitanicum using morphometric measures of vegetative and reproductive structures. T. lusitanicum is a gynodioecious species. Male sterile (female) individuals showed greater developmental instability at all sites. Plants located inland had higher developmental instability of vegetative characters and lower developmental instability of reproductive characters than coastal plants. These results support the contentions that (1) developmental instability is affected more by the disruption of co-adapted gene complexes than by lower heterozygosity, and (2) different habitat characteristics result in the differential response of vegetative and reproductive structures.

Using Popular Culture in Developmental Writing

ERIC Educational Resources Information Center

Barnes, Sharon L.

2006-01-01

Using popular culture in my developmental writing course has prompted me to reconsider what it means to create successful developmental writing assignments. Having slipped into the questionable habit of assuming that removing complexity makes an assignment appropriate for developing writers, I pared down a fairly open-ended "media…

Using Quantitative Structure-Activity Relationship Modeling to Quantitatively Predict the Developmental Toxicity of Halogenated Azole compounds

EPA Science Inventory

Developmental toxicity is a relevant endpoint for the comprehensive assessment of human health risk from chemical exposure. However, animal developmental toxicity studies remain unavailable for many environmental contaminants due to the complexity and cost of these types of analy...

Wash functions downstream of Rho1 GTPase in a subset of Drosophila immune cell developmental migrations

PubMed Central

Verboon, Jeffrey M.; Rahe, Travis K.; Rodriguez-Mesa, Evelyn; Parkhurst, Susan M.

2015-01-01

Drosophila immune cells, the hemocytes, undergo four stereotypical developmental migrations to populate the embryo, where they provide immune reconnoitering, as well as a number of non–immune-related functions necessary for proper embryogenesis. Here, we describe a role for Rho1 in one of these developmental migrations in which posteriorly located hemocytes migrate toward the head. This migration requires the interaction of Rho1 with its downstream effector Wash, a Wiskott–Aldrich syndrome family protein. Both Wash knockdown and a Rho1 transgene harboring a mutation that prevents Wash binding exhibit the same developmental migratory defect as Rho1 knockdown. Wash activates the Arp2/3 complex, whose activity is needed for this migration, whereas members of the WASH regulatory complex (SWIP, Strumpellin, and CCDC53) are not. Our results suggest a WASH complex–independent signaling pathway to regulate the cytoskeleton during a subset of hemocyte developmental migrations. PMID:25739458

Ultrastructural evidence of the ehrlichial developmental cycle in naturally infected Ixodes persulcatus ticks in the course of coinfection with Rickettsia, Borrelia, and a flavivirus.

PubMed

Popov, Vsevolod L; Korenberg, Edward I; Nefedova, Valentina V; Han, Violet C; Wen, Julie W; Kovalevskii, Yurii V; Gorelova, Natalia B; Walker, David H

2007-01-01

Ehrlichiae are small gram-negative obligately intracellular bacteria that multiply within vacuoles of their host cells and are associated for a part of their life cycle with ticks, which serve as vectors for vertebrate hosts. Two morphologically and physiologically different ehrlichial cell types, reticulate cells (RC) and dense-cored cells (DC), are observed during experimental infection of cell cultures, mice, and ticks. Dense-cored cells and reticulate cells in vertebrate cell lines alternate in a developmental cycle. We observed ultrastructure of RC and DC of Ehrlichia muris in morulae in salivary gland cells and coinfection with Borrelia burgdorferi sensu lato (sl), "Candidatus Rickettsia tarasevichiae," and a flavivirus (presumably, tick-borne encephalitis virus [TBEV]) of Ixodes persulcatusticks collected in the Cis-Ural region of Russia. Polymerase chain reaction revealed 326 (81.5%) of 400 ticks carrying at least one infectious agent, and 41.5% (166 ticks) were coinfected with two to four agents. Ehrlichiae and rickettsiae were identified by sequencing of 359 bp of the 16S rRNA gene of E. muris and of 440 bp of the 16S rRNA gene and 385 bp of the gltA gene of "R. tarasevichiae." Different organs of the same tick harbored different microorganisms: TBEV in salivary gland and borreliae in midgut; E. muris in salivary gland; and "R. tarasevichiae" in midgut epithelium. Salivary gland cells contained both RC and DC, a finding that confirmed the developmental cycle in naturally infected ticks. Dense-cored cells in tick salivary glands were denser and of more irregular shape than DC in cell cultures. Ehrlichia-infected salivary gland cells had lysed cytoplasm, suggesting pathogenicity of E. muris for the tick host at the cellular level, as well as potential transmission during feeding. Rickettsiae in the midgut epithelial cells multiplied to significant numbers without altering the host cell ultrastructure. This is the first demonstration of E. muris, "R. tarasevichiae," and the ehrlichial developmental cycle in naturally infected I. persulcatus sticks.

The developmental proteome of Drosophila melanogaster

PubMed Central

Casas-Vila, Nuria; Bluhm, Alina; Sayols, Sergi; Dinges, Nadja; Dejung, Mario; Altenhein, Tina; Kappei, Dennis; Altenhein, Benjamin; Roignant, Jean-Yves; Butter, Falk

2017-01-01

Drosophila melanogaster is a widely used genetic model organism in developmental biology. While this model organism has been intensively studied at the RNA level, a comprehensive proteomic study covering the complete life cycle is still missing. Here, we apply label-free quantitative proteomics to explore proteome remodeling across Drosophila’s life cycle, resulting in 7952 proteins, and provide a high temporal-resolved embryogenesis proteome of 5458 proteins. Our proteome data enabled us to monitor isoform-specific expression of 34 genes during development, to identify the pseudogene Cyp9f3Ψ as a protein-coding gene, and to obtain evidence of 268 small proteins. Moreover, the comparison with available transcriptomic data uncovered examples of poor correlation between mRNA and protein, underscoring the importance of proteomics to study developmental progression. Data integration of our embryogenesis proteome with tissue-specific data revealed spatial and temporal information for further functional studies of yet uncharacterized proteins. Overall, our high resolution proteomes provide a powerful resource and can be explored in detail in our interactive web interface. PMID:28381612

The flowering hormone florigen functions as a general systemic regulator of growth and termination

PubMed Central

Shalit, Akiva; Rozman, Alexander; Goldshmidt, Alexander; Alvarez, John P.; Bowman, John L.; Eshed, Yuval; Lifschitz, Eliezer

2009-01-01

The florigen paradigm implies a universal flowering-inducing hormone that is common to all flowering plants. Recent work identified FT orthologues as originators of florigen and their polypeptides as the likely systemic agent. However, the developmental processes targeted by florigen remained unknown. Here we identify local balances between SINGLE FLOWER TRUSS (SFT), the tomato precursor of florigen, and SELF-PRUNING (SP), a potent SFT-dependent SFT inhibitor as prime targets of mobile florigen. The graft-transmissible impacts of florigen on organ-specific traits in perennial tomato show that in addition to import by shoot apical meristems, florigen is imported by organs in which SFT is already expressed. By modulating local SFT/SP balances, florigen confers differential flowering responses of primary and secondary apical meristems, regulates the reiterative growth and termination cycles typical of perennial plants, accelerates leaf maturation, and influences the complexity of compound leaves, the growth of stems and the formation of abscission zones. Florigen is thus established as a plant protein functioning as a general growth hormone. Developmental interactions and a phylogenetic analysis suggest that the SFT/SP regulatory hierarchy is a recent evolutionary innovation unique to flowering plants. PMID:19416824

A developmental cycle masks output from the circadian oscillator under conditions of choline deficiency in Neurospora.

PubMed

Shi, Mi; Larrondo, Luis F; Loros, Jennifer J; Dunlap, Jay C

2007-12-11

In Neurospora, metabolic oscillators coexist with the circadian transcriptional/translational feedback loop governed by the FRQ (Frequency) and WC (White Collar) proteins. One of these, a choline deficiency oscillator (CDO) observed in chol-1 mutants grown under choline starvation, drives an uncompensated long-period developmental cycle ( approximately 60-120 h). To assess possible contributions of this metabolic oscillator to the circadian system, molecular and physiological rhythms were followed in liquid culture under choline starvation, but these only confirmed that an oscillator with a normal circadian period length can run under choline starvation. This finding suggested that long-period developmental cycles elicited by nutritional stress could be masking output from the circadian system, although a caveat was that the CDO sometimes requires several days to become consolidated. To circumvent this and observe both oscillators simultaneously, we used an assay using a codon-optimized luciferase to follow the circadian oscillator. Under conditions where the long-period, uncompensated, CDO-driven developmental rhythm was expressed for weeks in growth tubes, the luciferase rhythm in the same cultures continued in a typical compensated manner with a circadian period length dependent on the allelic state of frq. Periodograms revealed no influence of the CDO on the circadian oscillator. Instead, the CDO appears as a cryptic metabolic oscillator that can, under appropriate conditions, assume control of growth and development, thereby masking output from the circadian system. frq-driven luciferase as a reporter of the circadian oscillator may in this way provide a means for assessing prospective role(s) of metabolic and/or ancillary oscillators within cellular circadian systems.

The genome and developmental transcriptome of the strongylid nematode Haemonchus contortus

PubMed Central

2013-01-01

Background The barber's pole worm, Haemonchus contortus, is one of the most economically important parasites of small ruminants worldwide. Although this parasite can be controlled using anthelmintic drugs, resistance against most drugs in common use has become a widespread problem. We provide a draft of the genome and the transcriptomes of all key developmental stages of H. contortus to support biological and biotechnological research areas of this and related parasites. Results The draft genome of H. contortus is 320 Mb in size and encodes 23,610 protein-coding genes. On a fundamental level, we elucidate transcriptional alterations taking place throughout the life cycle, characterize the parasite's gene silencing machinery, and explore molecules involved in development, reproduction, host-parasite interactions, immunity, and disease. The secretome of H. contortus is particularly rich in peptidases linked to blood-feeding activity and interactions with host tissues, and a diverse array of molecules is involved in complex immune responses. On an applied level, we predict drug targets and identify vaccine molecules. Conclusions The draft genome and developmental transcriptome of H. contortus provide a major resource to the scientific community for a wide range of genomic, genetic, proteomic, metabolomic, evolutionary, biological, ecological, and epidemiological investigations, and a solid foundation for biotechnological outcomes, including new anthelmintics, vaccines and diagnostic tests. This first draft genome of any strongylid nematode paves the way for a rapid acceleration in our understanding of a wide range of socioeconomically important parasites of one of the largest nematode orders. PMID:23985341

Microanatomy and Development of the Dwarf Male of Symbion pandora (Phylum Cycliophora): New Insights from Ultrastructural Investigation Based on Serial Section Electron Microscopy

PubMed Central

Neves, Ricardo Cardoso; Reichert, Heinrich

2015-01-01

Cycliophorans have a complex life cycle that involves several sexual and asexual stages. One of the sexual stages is the 40 μm-long dwarf male, which is among the smallest free-living metazoans. Although the dwarf male has a highly complex body plan, this minute organism is composed of a very low number of somatic cells (~50). The developmental processes that give rise to this unique phenotype are largely unknown. Here we use high resolution serial block face—scanning electron microscopy to analyze the anatomy and morphogenesis of three cycliophoran dwarf males at different developmental stages ranging from internal bud to mature male. The anatomical and morphological features of the mature dwarf male stage reported here largely correspond to those reported in earlier studies. Interestingly, the organs that typically characterize the anatomy of the mature dwarf male, e.g., muscles, brain, testis and glands, are already formed in the young male. However, there are striking differences between the mature male and young male stages at the level of cellular architecture. Thus, while the young male stage, like the internal bud stage, possesses approximately 200 nucleated cells, the mature male stage comprises only around 50 nucleated cells; muscle and epidermal cells of the mature male lack nuclei. Moreover, the total body volume of the mature male is only 63% of the body of the young male implying that the maturation of the young male into a mature male involves a marked reduction of internal body volume, mainly by massive nuclei loss. Our comparative analysis of these dwarf male specimens reveals unprecedented insight into the striking morphological and developmental differences that characterize these highly miniaturized male stages both at the level of body organization and at the level of cellular ultrastructure. PMID:25875482

Multivariate Longitudinal Methods for Studying Developmental Relationships between Depression and Academic Achievement

ERIC Educational Resources Information Center

Grimm, Kevin J.

2007-01-01

Recent advances in methods and computer software for longitudinal data analysis have pushed researchers to more critically examine developmental theories. In turn, researchers have also begun to push longitudinal methods by asking more complex developmental questions. One such question involves the relationships between two developmental…

Ca cycling and isotopic fluxes in forested ecosystems in Hawaii

USGS Publications Warehouse

Wiegand, B.A.; Chadwick, O.A.; Vitousek, P.M.; Wooden, J.L.

2005-01-01

Biogeochemical processes fractionate Ca isotopes in plants and soils along a 4 million year developmental sequence in the Hawaiian Islands. We observed that plants preferentially take up 40Ca relative to 44Ca, and that biological fractionation and changes in the relative contributions from volcanic and marine sources produce a significant increase in 44Ca in soil exchangeable pools. Our results imply moderate fluxes enriched in 44Ca from strongly nutrient-depleted old soils, in contrast with high 40Ca fluxes in young and little weathered environments. In addition, biological fractionation controls divergent geochemical pathways of Ca and Sr in the plant-soil system. While Ca depletes progressively with increasing soil age, Sr/Ca ratios increase systematically. Sr isotope ratios provide a valuable tracer for provenance studies of alkaline earth elements in forested ecosystems, but its usefulness is limited when deciphering biogeochemical processes involved in the terrestrial Ca cycle. Ca isotopes in combination with Sr/ Ca ratios reveal more complex processes involved in the biogeochemistry of Ca and Sr. Copyright 2005 by the American Geophysical Union.

The final cut: cell polarity meets cytokinesis at the bud neck in S. cerevisiae.

PubMed

Juanes, Maria Angeles; Piatti, Simonetta

2016-08-01

Cell division is a fundamental but complex process that gives rise to two daughter cells. It includes an ordered set of events, altogether called "the cell cycle", that culminate with cytokinesis, the final stage of mitosis leading to the physical separation of the two daughter cells. Symmetric cell division equally partitions cellular components between the two daughter cells, which are therefore identical to one another and often share the same fate. In many cases, however, cell division is asymmetrical and generates two daughter cells that differ in specific protein inheritance, cell size, or developmental potential. The budding yeast Saccharomyces cerevisiae has proven to be an excellent system to investigate the molecular mechanisms governing asymmetric cell division and cytokinesis. Budding yeast is highly polarized during the cell cycle and divides asymmetrically, producing two cells with distinct sizes and fates. Many components of the machinery establishing cell polarization during budding are relocalized to the division site (i.e., the bud neck) for cytokinesis. In this review we recapitulate how budding yeast cells undergo polarized processes at the bud neck for cell division.

A Review of "Life Cycle: How We Grow and Change"

ERIC Educational Resources Information Center

Digioia, Melissa Keyes

2010-01-01

Sexuality education curricula designed for youths with special needs are sparse. "Life Cycle: How We Grow and Change" (Vavricheck & Tolle, 2008) is a new curriculum by clinical social workers Sherrie Mansfield Vavricheck and R. Kay Tolle. Each chapter addresses a particular developmental stage between birth and death. Lessons within each chapter…

The Adult Life Cycle: Exploration and Implications.

ERIC Educational Resources Information Center

Baile, Susan

Most of the frameworks that have been constructed to mark off the changes in the cycle of adulthood are characterized by a particular focus such as developmental ages, the role of age and timing, or ego development. The theory of Erik Erikson, based upon his clinical observations, represents these crucial turning points in human development: ages…

Assisted Cycling Tours

ERIC Educational Resources Information Center

Hollingsworth, Jan Carter

2008-01-01

This article discusses Assisted Cycling Tours (ACT), a Westminster, Colorado based 501(c)3, non-profit that is offering the joy of bicycle tours in breathtaking, scenic locations to children and adults with developmental and physical disabilities and their families. ACT was founded by Bob Matter and his son David with a goal of opening up the…

The evolution of the land plant life cycle.

PubMed

Niklas, Karl J; Kutschera, Ulrich

2010-01-01

The extant land plants are unique among the monophyletic clade of photosynthetic eukaryotes, which consists of the green algae (chlorophytes), the charophycean algae (charophytes), numerous groups of unicellular algae (prasinophytes) and the embryophytes, by possessing, firstly, a sexual life cycle characterized by an alternation between a haploid, gametophytic and a diploid, sporophytic multicellular generation; secondly, the formation of egg cells within multicellular structures called archegonia; and, thirdly, the retention of the zygote and diploid sporophyte embryo within the archegonium. We review the developmental, paleobotanical and molecular evidence indicating that: the embryophytes descended from a charophyte-like ancestor; this common ancestor had a life cycle with only a haploid multicellular generation; and the most ancient (c. 410 Myr old) land plants (e.g. Cooksonia, Rhynia and Zosterophyllum) had a dimorphic life cycle (i.e. their haploid and diploid generations were morphologically different). On the basis of these findings, we suggest that the multicellular reproductive structures of extant charophytes and embryophytes are developmentally homologous, and that those of the embryophytes evolved by virtue of the co-option and re-deployment of ancient algal homeodomain gene networks.

Child-Bearing Decision Making Among Women Previously Treated for Breast Cancer

DTIC Science & Technology

1997-04-01

this kind of study is an essential preliminary step to developing meaningful theory-driven psychosocial research on the issues of childbearing among...than older women with the disease and may experience unique vulnerability factors. Adult developmental theory ( Erikson , 1963; Levinson, Darrow, Klein...variety of developmental tasks characterize different stages of the adult life cycle. Several significant tasks for younger women are likely to be

Life cycle stage and water depth affect flooding-induced adventitious root formation in the terrestrial species Solanum dulcamara

PubMed Central

Zhang, Qian; Visser, Eric J. W.; de Kroon, Hans; Huber, Heidrun

2015-01-01

Background and Aims Flooding can occur at any stage of the life cycle of a plant, but often adaptive responses of plants are only studied at a single developmental stage. It may be anticipated that juvenile plants may respond differently from mature plants, as the amount of stored resources may differ and morphological changes can be constrained. Moreover, different water depths may require different strategies to cope with the flooding stress, the expression of which may also depend on developmental stage. This study investigated whether flooding-induced adventitious root formation and plant growth were affected by flooding depth in Solanum dulcamara plants at different developmental stages. Methods Juvenile plants without pre-formed adventitious root primordia and mature plants with primordia were subjected to shallow flooding or deep flooding for 5 weeks. Plant growth and the timing of adventitious root formation were monitored during the flooding treatments. Key Results Adventitious root formation in response to shallow flooding was significantly constrained in juvenile S. dulcamara plants compared with mature plants, and was delayed by deep flooding compared with shallow flooding. Complete submergence suppressed adventitious root formation until up to 2 weeks after shoots restored contact with the atmosphere. Independent of developmental stage, a strong positive correlation was found between adventitious root formation and total biomass accumulation during shallow flooding. Conclusions The potential to deploy an escape strategy (i.e. adventitious root formation) may change throughout a plant’s life cycle, and is largely dependent on flooding depth. Adaptive responses at a given stage of the life cycle thus do not necessarily predict how the plant responds to flooding in another growth stage. As variation in adventitious root formation also correlates with finally attained biomass, this variation may form the basis for variation in resistance to shallow flooding among plants. PMID:26105188

Life cycle stage and water depth affect flooding-induced adventitious root formation in the terrestrial species Solanum dulcamara.

PubMed

Zhang, Qian; Visser, Eric J W; de Kroon, Hans; Huber, Heidrun

2015-08-01

Flooding can occur at any stage of the life cycle of a plant, but often adaptive responses of plants are only studied at a single developmental stage. It may be anticipated that juvenile plants may respond differently from mature plants, as the amount of stored resources may differ and morphological changes can be constrained. Moreover, different water depths may require different strategies to cope with the flooding stress, the expression of which may also depend on developmental stage. This study investigated whether flooding-induced adventitious root formation and plant growth were affected by flooding depth in Solanum dulcamara plants at different developmental stages. Juvenile plants without pre-formed adventitious root primordia and mature plants with primordia were subjected to shallow flooding or deep flooding for 5 weeks. Plant growth and the timing of adventitious root formation were monitored during the flooding treatments. Adventitious root formation in response to shallow flooding was significantly constrained in juvenile S. dulcamara plants compared with mature plants, and was delayed by deep flooding compared with shallow flooding. Complete submergence suppressed adventitious root formation until up to 2 weeks after shoots restored contact with the atmosphere. Independent of developmental stage, a strong positive correlation was found between adventitious root formation and total biomass accumulation during shallow flooding. The potential to deploy an escape strategy (i.e. adventitious root formation) may change throughout a plant's life cycle, and is largely dependent on flooding depth. Adaptive responses at a given stage of the life cycle thus do not necessarily predict how the plant responds to flooding in another growth stage. As variation in adventitious root formation also correlates with finally attained biomass, this variation may form the basis for variation in resistance to shallow flooding among plants. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Managing Tensions between Evaluation and Research: Illustrative Cases of Developmental Evaluation in the Context of Research

ERIC Educational Resources Information Center

Rey, Lynda; Tremblay, Marie-Claude; Brousselle, Astrid

2014-01-01

Developmental evaluation (DE), essentially conceptualized by Patton over the past 30 years, is a promising evaluative approach intended to support social innovation and the deployment of complex interventions. Its use is often justified by the complex nature of the interventions being evaluated and the need to produce useful results in real time.…

New discoveries in the transmission biology of sleeping sickness parasites: applying the basics.

PubMed

MacGregor, Paula; Matthews, Keith R

2010-09-01

The sleeping sickness parasite, Trypanosoma brucei, must differentiate in response to the changing environments that it encounters during its complex life cycle. One developmental form, the bloodstream stumpy stage, plays an important role in infection dynamics and transmission of the parasite. Recent advances have shed light on the molecular mechanisms by which these stumpy forms differentiate as they are transmitted from the mammalian host to the insect vector of sleeping sickness, tsetse flies. These molecular advances now provide improved experimental tools for the study of stumpy formation and function within the mammalian bloodstream. They also offer new routes to therapy via high-throughput screens for agents that accelerate parasite development. Here, we shall discuss the recent advances that have been made and the prospects for future research now available.

Mining meiosis and gametogenesis with DNA microarrays.

PubMed

Schlecht, Ulrich; Primig, Michael

2003-04-01

Gametogenesis is a key developmental process that involves complex transcriptional regulation of numerous genes including many that are conserved between unicellular eukaryotes and mammals. Recent expression-profiling experiments using microarrays have provided insight into the co-ordinated transcription of several hundred genes during mitotic growth and meiotic development in budding and fission yeast. Furthermore, microarray-based studies have identified numerous loci that are regulated during the cell cycle or expressed in a germ-cell specific manner in eukaryotic model systems like Caenorhabditis elegans, Mus musculus as well as Homo sapiens. The unprecedented amount of information produced by post-genome biology has spawned novel approaches to organizing biological knowledge using currently available information technology. This review outlines experiments that contribute to an emerging comprehensive picture of the molecular machinery governing sexual reproduction in eukaryotes.

The evolution of life cycle complexity in aphids: Ecological optimization or historical constraint?

PubMed

Hardy, Nate B; Peterson, Daniel A; von Dohlen, Carol D

2015-06-01

For decades, biologists have debated why many parasites have obligate multihost life cycles. Here, we use comparative phylogenetic analyses of aphids to evaluate the roles of ecological optimization and historical constraint in the evolution of life cycle complexity. If life cycle complexity is adaptive, it should be evolutionarily labile, that is, change in response to selection. We provide evidence that this is true in some aphids (aphidines), but not others (nonaphidines)-groups that differ in the intensity of their relationships with primary hosts. Next, we test specific mechanisms by which life cycle complexity could be adaptive or a constraint. We find that among aphidines there is a strong association between complex life cycles and polyphagy but only a weak correlation between life cycle complexity and reproductive mode. In contrast, among nonaphidines the relationship between life cycle complexity and host breadth is weak but the association between complex life cycles and sexual reproduction is strong. Thus, although the adaptiveness of life cycle complexity appears to be lineage specific, across aphids, life cycle evolution appears to be tightly linked with the evolution of other important natural history traits. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Developmental kinetics of pig embryos by parthenogenetic activation or by handmade cloning.

PubMed

Li, J; Li, R; Liu, Y; Villemoes, K; Purup, S; Callesen, H

2013-10-01

The developmental kinetics of pig embryos produced by parthenogenetic activation without (PAZF) or with (PAZI) zona pellucida or by handmade cloning (HMC) was compared by time-lapse videography. After cumulus cell removal, the matured oocytes were either left zona intact (PAZI) or were made zona free by pronase digestion (PAZF) before they were activated (PA). Other matured oocytes were used for HMC based on foetal fibroblast cells. On Day 0 (day of PA or reconstruction), the embryos were cultured for 7 days in vitro in our time-lapse system. Pictures were taken every 30 min, and afterwards, each cell cycle was identified for each embryo to be analysed. Results showed that the PA embryos (both PAZF and PAZI) had shorter first cell cycle compared with HMC (17.4. 17.8 vs 23.6 h), but had a longer time length from four cell to morula stages (57.9, 53.8 vs 44.9 h). However, at the second cell cycle, PAZF embryos needed shorter time, while PAZI embryos had similar time length as HMC embryos, and both were longer than PAZF (23.4, 24.8 vs 14.6 h). Both PAZF and PAZI embryos used similar time to reach the blastocyst stage, and this was later than HMC embryos. In addition, when all of these embryos were grouped into viable (developed to blastocysts) and non-viable (not developed to blastocysts), the only difference in the time length was observed on the first cell cycle (18.6 vs 24.5 h), but not on the later cell cycles. In conclusion, our results not only give detailed information regarding the time schedule of in vitro-handled pig embryos, but also indicate that the first cell cycle could be used as a selecting marker for embryo viability. However, to evaluate the effect of the produced techniques, the whole time schedule of the pre-implantation developmental kinetics should be observed. © 2013 Blackwell Verlag GmbH.

Multi-scale computational modeling of developmental biology.

PubMed

Setty, Yaki

2012-08-01

Normal development of multicellular organisms is regulated by a highly complex process in which a set of precursor cells proliferate, differentiate and move, forming over time a functioning tissue. To handle their complexity, developmental systems can be studied over distinct scales. The dynamics of each scale is determined by the collective activity of entities at the scale below it. I describe a multi-scale computational approach for modeling developmental systems and detail the methodology through a synthetic example of a developmental system that retains key features of real developmental systems. I discuss the simulation of the system as it emerges from cross-scale and intra-scale interactions and describe how an in silico study can be carried out by modifying these interactions in a way that mimics in vivo experiments. I highlight biological features of the results through a comparison with findings in Caenorhabditis elegans germline development and finally discuss about the applications of the approach in real developmental systems and propose future extensions. The source code of the model of the synthetic developmental system can be found in www.wisdom.weizmann.ac.il/~yaki/MultiScaleModel. yaki.setty@gmail.com Supplementary data are available at Bioinformatics online.

A G protein alpha null mutation confers prolificacy potential in maize

DOE PAGES

Urano, Daisuke; Jackson, David; Jones, Alan M.

2015-05-06

Plasticity in plant development is controlled by environmental signals through largely unknown signalling networks. Signalling coupled by the heterotrimeric G protein complex underlies various developmental pathways in plants. The morphology of two plastic developmental pathways, root system architecture and female inflorescence formation, was quantitatively assessed in a mutant compact plant 2 (ct2) lacking the alpha subunit of the heterotrimeric G protein complex in maize. The ct2 mutant partially compensated for a reduced shoot height by increased total leaf number, and had far more ears, even in the presence of pollination signals. Lastly, the maize heterotrimeric G protein complex is importantmore » in some plastic developmental traits in maize. In particular, the maize Gα subunit is required to dampen the overproduction of female inflorescences.« less

A C. trachomatis Cloning Vector and the Generation of C. trachomatis Strains Expressing Fluorescent Proteins under the Control of a C. trachomatis Promoter

PubMed Central

Agaisse, Hervé; Derré, Isabelle

2013-01-01

Here we describe a versatile cloning vector for conducting genetic experiments in C. trachomatis. We successfully expressed various fluorescent proteins (i.e. GFP, mCherry and CFP) from C. trachomatis regulatory elements (i.e. the promoter and terminator of the incDEFG operon) and showed that the transformed strains produced wild type amounts of infectious particles and recapitulated major features of the C. trachomatis developmental cycle. C. trachomatis strains expressing fluorescent proteins are valuable tools for studying the C. trachomatis developmental cycle. For instance, we show the feasibility of investigating the dynamics of inclusion fusion and interaction with host proteins and organelles by time-lapse video microscopy. PMID:23441233

The Developmental Approach to Child and Adult Health

PubMed Central

Conti, Gabriella; Heckman, James J.

2013-01-01

Pediatricians should consider the costs and benefits of preventing rather than treating childhood diseases. We present an integrated developmental approach to child and adult health that considers the costs and benefits of interventions over the life cycle. We suggest policies to promote child health that are currently outside the boundaries of conventional pediatrics. We discuss current challenges to the field and suggest avenues for future research. PMID:23547057

Developmental transitions in C. elegans larval stages.

PubMed

Rougvie, Ann E; Moss, Eric G

2013-01-01

Molecular mechanisms control the timing, sequence, and synchrony of developmental events in multicellular organisms. In Caenorhabditis elegans, these mechanisms are revealed through the analysis of mutants with "heterochronic" defects: cell division or differentiation patterns that occur in the correct lineage, but simply at the wrong time. Subsets of cells in these mutants thus express temporal identities normally restricted to a different life stage. A seminal finding arising from studies of the heterochronic genes was the discovery of miRNAs; these tiny miRNAs are now a defining feature of the pathway. A series of sequentially expressed miRNAs guide larval transitions through stage-specific repression of key effector molecules. The wild-type lineage patterns are executed as discrete modules programmed between temporal borders imposed by the molting cycles. How these successive events are synchronized with the oscillatory molting cycle is just beginning to come to light. Progression through larval stages can be specifically, yet reversibly, halted in response to environmental cues, including nutrient availability. Here too, heterochronic genes and miRNAs play key roles. Remarkably, developmental arrest can, in some cases, either mask or reveal timing defects associated with mutations. In this chapter, we provide an overview of how the C. elegans heterochronic gene pathway guides developmental transitions during continuous and interrupted larval development. © 2013 Elsevier Inc. All rights reserved.

Developmental Processes in Peer Problems of Children with ADHD in the MTA Study1: Developmental Cascades and Vicious Cycles

PubMed Central

Murray-Close, Dianna; Hoza, Betsy; Hinshaw, Stephen P.; Arnold, L Eugene; Swanson, James; Jensen, Peter S.; Hechtman, Lily; Wells, Karen

2010-01-01

We examined the developmental processes involved in peer problems among children (M age = 10.41 years) previously diagnosed with ADHD at study entry (N = 536) and a comparison group (N = 284). Participants were followed over a 6-year period ranging from middle childhood to adolescence. At four assessment periods, measures of aggression, social skills, positive illusory biases (in the social and behavioral domains), and peer rejection were assessed. Results indicated that children from the ADHD group exhibited difficulties in each of these areas at the first assessment. Moreover, there were vicious cycles among problems over time. For example, peer rejection was related to impaired social skills, which in turn predicted later peer rejection. Problems also tended to “spill over” into other areas, which in turn compromised functioning in additional areas across development, leading to cascading effects over time. The findings held even when controlling for age and were similar for males and females, the ADHD and comparison groups, and among ADHD treatment groups. The results suggest that the peer problems among children with and without ADHD may reflect similar processes; however, children with ADHD exhibit greater difficulties negotiating important developmental tasks. Implications for interventions are discussed. PMID:20883582

[Life cycle of the trematode Echinochasmus spinosus Odhner, 1911 (Echinostomatidae) in the natural conditions of Primorye].

PubMed

Besprozvannykh, V V

2011-01-01

Life cycle and developmental stages of the trematode Echinochasmus spinosus Odhner, 1911 are described. As it was established experimentally, in the conditions of Primorsky Krai circulation of the trematode involves first intermediate host, mollusk Parafossarulus spiridonovi, and the second one, freshwater fishes. Adult worms were reared in chicken.

The Family Life Cycle and Critical Transitions: Utilizing Cinematherapy to Facilitate Understanding and Increase Communication

ERIC Educational Resources Information Center

Ballard, Mary B.

2012-01-01

Transitioning successfully from one stage of development to the next in the family life cycle requires the accomplishment of certain developmental tasks. Couples and families who fail to accomplish these tasks often become "stuck" and unable to move forward. This impasse frequently leads to heightened stress reactions and crippled channels of…

Economic and Power Relations Among Urban Tinkers: The Role of Women

ERIC Educational Resources Information Center

Gmelch, Sharon Bohn

1977-01-01

Examines the role of women in the economic and social organization of Irish Tinkers living in Dublin. Focuses on the influence of both age and life cycle events upon authority and power relationships between the sexes. Finds that although Tinker society is clearly male-dominated, women's roles follow a developmental cycle. (Author/GC)

The Evaluation Life Cycle: A Retrospective Assessment of Stages and Phases of the Circles of Care Initiative

ERIC Educational Resources Information Center

Bess, Gary; Allen, James; Deters, Pamela B.

2004-01-01

A life cycle metaphor characterizes the evolving relationship between the evaluator and program staff. This framework suggests that common developmental dynamics occur in roughly the same order across groups and settings. There are stage-specific dynamics that begin with Pre-History, which characterize the relationship between the grantees and…

The Adult Life Spiral: A Critique of the Life Cycle Model.

ERIC Educational Resources Information Center

Stein, Peter; Etzkowitz, Henry

We can identify and describe alternate paths of adulthood utilizing data from interviews with single adults. Our review of major models used in adulthood studies suggests that a developmental model, such as Daniel Levinson's life cycle model, is too tied to the notion of the imminent unfolding of the life course. The age-stratification theory…

DEVELOPMENTAL NEUROTOXICITY OF ORGANOPHOSPHATES TARGETS CELL CYCLE AND APOPTOSIS, REVEALED BY TRANSCRIPTIONAL PROFILES IN VIVO AND IN VITRO

PubMed Central

Slotkin, Theodore A.; Seidler, Frederic J.

2012-01-01

Developmental organophosphate exposure reduces the numbers of neural cells, contributing to neurobehavioral deficits. We administered chlorpyrifos or diazinon to newborn rats on postnatal days 1–4, in doses straddling the threshold for barely-detectable cholinesterase, and evaluated gene expression in the cell cycle and apoptosis pathways on postnatal day 5. Both organophosphates evoked transcriptional changes in 20–25% of the genes in each category; chlorpyrifos and diazinon targeted the same genes, with similar magnitudes of change, as evidenced by high concordance. Furthermore, the same effects were obtained with doses above or below the threshold for cholinesterase inhibition, indicating a mechanism unrelated to anticholinesterase actions. We then evaluated the effects of chlorpyrifos in undifferentiated and differentiating PC12 cells and found even greater targeting of cell cycle and apoptosis genes, affecting up to 40% of all genes in the pathways. Notably, the genes affected in undifferentiated cells were not concordant with those in differentiating cells, pointing to dissimilar outcomes dependent on developmental stage. The in vitro model successfully identified 60–70% of the genes affected by chlorpyrifos in vivo, indicating that the effects are exerted directly on developing neural cells. Our results show that organophosphates target the genes regulating the cell cycle and apoptosis in the developing brain and in neuronotypic cells in culture, with the pattern of vulnerability dependent on the specific stage of development. Equally important, these effects do not reflect actions on cholinesterase and operate at exposures below the threshold for any detectable inhibition of this enzyme. PMID:22222554

Developmental neurotoxicity of organophosphates targets cell cycle and apoptosis, revealed by transcriptional profiles in vivo and in vitro.

PubMed

Slotkin, Theodore A; Seidler, Frederic J

2012-03-01

Developmental organophosphate exposure reduces the numbers of neural cells, contributing to neurobehavioral deficits. We administered chlorpyrifos or diazinon to newborn rats on postnatal days 1-4, in doses straddling the threshold for barely-detectable cholinesterase inhibition, and evaluated gene expression in the cell cycle and apoptosis pathways on postnatal day 5. Both organophosphates evoked transcriptional changes in 20-25% of the genes in each category; chlorpyrifos and diazinon targeted the same genes, with similar magnitudes of change, as evidenced by high concordance. Furthermore, the same effects were obtained with doses above or below the threshold for cholinesterase inhibition, indicating a mechanism unrelated to anticholinesterase actions. We then evaluated the effects of chlorpyrifos in undifferentiated and differentiating PC12 cells and found even greater targeting of cell cycle and apoptosis genes, affecting up to 40% of all genes in the pathways. Notably, the genes affected in undifferentiated cells were not concordant with those in differentiating cells, pointing to dissimilar outcomes dependent on developmental stage. The in vitro model successfully identified 60-70% of the genes affected by chlorpyrifos in vivo, indicating that the effects are exerted directly on developing neural cells. Our results show that organophosphates target the genes regulating the cell cycle and apoptosis in the developing brain and in neuronotypic cells in culture, with the pattern of vulnerability dependent on the specific stage of development. Equally important, these effects do not reflect actions on cholinesterase and operate at exposures below the threshold for any detectable inhibition of this enzyme. Copyright © 2011 Elsevier Inc. All rights reserved.

Silencing of genes involved in Anaplasma marginale-tick interactions affects the pathogen developmental cycle in Dermacentor variabilis.

PubMed

Kocan, Katherine M; Zivkovic, Zorica; Blouin, Edmour F; Naranjo, Victoria; Almazán, Consuelo; Mitra, Ruchira; de la Fuente, José

2009-07-16

The cattle pathogen, Anaplasma marginale, undergoes a developmental cycle in ticks that begins in gut cells. Transmission to cattle occurs from salivary glands during a second tick feeding. At each site of development two forms of A. marginale (reticulated and dense) occur within a parasitophorous vacuole in the host cell cytoplasm. However, the role of tick genes in pathogen development is unknown. Four genes, found in previous studies to be differentially expressed in Dermacentor variabilis ticks in response to infection with A. marginale, were silenced by RNA interference (RNAi) to determine the effect of silencing on the A. marginale developmental cycle. These four genes encoded for putative glutathione S-transferase (GST), salivary selenoprotein M (SelM), H+ transporting lysosomal vacuolar proton pump (vATPase) and subolesin. The impact of gene knockdown on A. marginale tick infections, both after acquiring infection and after a second transmission feeding, was determined and studied by light microscopy. Silencing of these genes had a different impact on A. marginale development in different tick tissues by affecting infection levels, the densities of colonies containing reticulated or dense forms and tissue morphology. Salivary gland infections were not seen in any of the gene-silenced ticks, raising the question of whether these ticks were able to transmit the pathogen. The results of this RNAi and light microscopic analyses of tick tissues infected with A. marginale after the silencing of genes functionally important for pathogen development suggest a role for these molecules during pathogen life cycle in ticks.

Receptor tyrosine kinase mutations in developmental syndromes and cancer: two sides of the same coin

PubMed Central

McDonell, Laura M.; Kernohan, Kristin D.; Boycott, Kym M.; Sawyer, Sarah L.

2015-01-01

Receptor tyrosine kinases (RTKs) are a family of ligand-binding cell surface receptors that regulate a wide range of essential cellular activities, including proliferation, differentiation, cell-cycle progression, survival and apoptosis. As such, these proteins play an important role during development and throughout life; germline mutations in genes encoding RTKs cause several developmental syndromes, while somatic alterations contribute to the pathogenesis of many aggressive cancers. This creates an interesting paradigm in which mutation timing, type and location in a gene leads to different cell signaling and biological responses, and ultimately phenotypic outcomes. In this review, we highlight the roles of RTKs in developmental disorders and cancer. The multifaceted roles of these receptors, their genetic signatures and their signaling during developmental morphogenesis and oncogenesis are discussed. Additionally, we propose that comparative analysis of RTK mutations responsible for developmental syndromes may shed light on those driving tumorigenesis. PMID:26152202

Morphological and Molecular Descriptors of the Developmental Cycle of Babesia divergens Parasites in Human Erythrocytes.

PubMed

Rossouw, Ingrid; Maritz-Olivier, Christine; Niemand, Jandeli; van Biljon, Riette; Smit, Annel; Olivier, Nicholas A; Birkholtz, Lyn-Marie

2015-05-01

Human babesiosis, especially caused by the cattle derived Babesia divergens parasite, is on the increase, resulting in renewed attentiveness to this potentially life threatening emerging zoonotic disease. The molecular mechanisms underlying the pathophysiology and intra-erythrocytic development of these parasites are poorly understood. This impedes concerted efforts aimed at the discovery of novel anti-babesiacidal agents. By applying sensitive cell biological and molecular functional genomics tools, we describe the intra-erythrocytic development cycle of B. divergens parasites from immature, mono-nucleated ring forms to bi-nucleated paired piriforms and ultimately multi-nucleated tetrads that characterizes zoonotic Babesia spp. This is further correlated for the first time to nuclear content increases during intra-erythrocytic development progression, providing insight into the part of the life cycle that occurs during human infection. High-content temporal evaluation elucidated the contribution of the different stages to life cycle progression. Moreover, molecular descriptors indicate that B. divergens parasites employ physiological adaptation to in vitro cultivation. Additionally, differential expression is observed as the parasite equilibrates its developmental stages during its life cycle. Together, this information provides the first temporal evaluation of the functional transcriptome of B. divergens parasites, information that could be useful in identifying biological processes essential to parasite survival for future anti-babesiacidal discoveries.

Brg1 coordinates multiple processes during retinogenesis and is a tumor suppressor in retinoblastoma

DOE PAGES

Aldiri, Issam; Ajioka, Itsuki; Xu, Beisi; ...

2015-12-01

Retinal development requires precise temporal and spatial coordination of cell cycle exit, cell fate specification, cell migration and differentiation. When this process is disrupted, retinoblastoma, a developmental tumor of the retina, can form. Epigenetic modulators are central to precisely coordinating developmental events, and many epigenetic processes have been implicated in cancer. Studying epigenetic mechanisms in development is challenging because they often regulate multiple cellular processes; therefore, elucidating the primary molecular mechanisms involved can be difficult. Here we explore the role of Brg1 (Smarca4) in retinal development and retinoblastoma in mice using molecular and cellular approaches. Brg1 was found to regulatemore » retinal size by controlling cell cycle length, cell cycle exit and cell survival during development. Brg1 was not required for cell fate specification but was required for photoreceptor differentiation and cell adhesion/polarity programs that contribute to proper retinal lamination during development. The combination of defective cell differentiation and lamination led to retinal degeneration in Brg1-deficient retinae. Despite the hypocellularity, premature cell cycle exit, increased cell death and extended cell cycle length, retinal progenitor cells persisted in Brg1-deficient retinae, making them more susceptible to retinoblastoma. In conclusion, ChIP-Seq analysis suggests that Brg1 might regulate gene expression through multiple mechanisms.« less

Brg1 coordinates multiple processes during retinogenesis and is a tumor suppressor in retinoblastoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aldiri, Issam; Ajioka, Itsuki; Xu, Beisi

Retinal development requires precise temporal and spatial coordination of cell cycle exit, cell fate specification, cell migration and differentiation. When this process is disrupted, retinoblastoma, a developmental tumor of the retina, can form. Epigenetic modulators are central to precisely coordinating developmental events, and many epigenetic processes have been implicated in cancer. Studying epigenetic mechanisms in development is challenging because they often regulate multiple cellular processes; therefore, elucidating the primary molecular mechanisms involved can be difficult. Here we explore the role of Brg1 (Smarca4) in retinal development and retinoblastoma in mice using molecular and cellular approaches. Brg1 was found to regulatemore » retinal size by controlling cell cycle length, cell cycle exit and cell survival during development. Brg1 was not required for cell fate specification but was required for photoreceptor differentiation and cell adhesion/polarity programs that contribute to proper retinal lamination during development. The combination of defective cell differentiation and lamination led to retinal degeneration in Brg1-deficient retinae. Despite the hypocellularity, premature cell cycle exit, increased cell death and extended cell cycle length, retinal progenitor cells persisted in Brg1-deficient retinae, making them more susceptible to retinoblastoma. In conclusion, ChIP-Seq analysis suggests that Brg1 might regulate gene expression through multiple mechanisms.« less

Spatial mapping and quantification of developmental branching morphogenesis.

PubMed

Short, Kieran; Hodson, Mark; Smyth, Ian

2013-01-15

Branching morphogenesis is a fundamental developmental mechanism that shapes the formation of many organs. The complex three-dimensional shapes derived by this process reflect equally complex genetic interactions between branching epithelia and their surrounding mesenchyme. Despite the importance of this process to normal adult organ function, analysis of branching has been stymied by the absence of a bespoke method to quantify accurately the complex spatial datasets that describe it. As a consequence, although many developmentally important genes are proposed to influence branching morphogenesis, we have no way of objectively assessing their individual contributions to this process. We report the development of a method for accurately quantifying many aspects of branching morphogenesis and we demonstrate its application to the study of organ development. As proof of principle we have employed this approach to analyse the developing mouse lung and kidney, describing the spatial characteristics of the branching ureteric bud and pulmonary epithelia. To demonstrate further its capacity to profile unrecognised genetic contributions to organ development, we examine Tgfb2 mutant kidneys, identifying elements of both developmental delay and specific spatial dysmorphology caused by haplo-insufficiency for this gene. This technical advance provides a crucial resource that will enable rigorous characterisation of the genetic and environmental factors that regulate this essential and evolutionarily conserved developmental mechanism.

Comparative anatomy and histology of developmental and parasitic stages in the life cycle of the lined sea anemone Edwardsiella lineata.

PubMed

Reitzel, Adam M; Daly, Marymegan; Sullivan, James C; Finnerty, John R

2009-02-01

The evolution of parasitism is often accompanied by profound changes to the developmental program. However, relatively few studies have directly examined the developmental evolution of parasitic species from free-living ancestors. The lined sea anemone Edwardsiella lineata is a relatively recently evolved parasite for which closely related free-living outgroups are known, including the starlet sea anemone Nematostella vectensis. The larva of E. lineata parasitizes the ctenophore Mnemiopsis leidyi, and, once embedded in its host, the anemone assumes a novel vermiform body plan. That we might begin to understand how the developmental program of this species has been transformed during the evolution of parasitism, we characterized the gross anatomy, histology, and cnidom of the parasitic stage, post-parasitic larval stage, and adult stage of the E. lineata life cycle. The distinct parasitic stage of the life cycle differs from the post-parasitic larva with respect to overall shape, external ciliation, cnida frequency, and tissue architecture. The parasitic stage and planula both contain holotrichs, a type of cnida not previously reported in Edwardsiidae. The internal morphology of the post-parasitic planula is extremely similar to the adult morphology, with a complete set of mesenterial tissue and musculature despite this stage having little external differentiation. Finally, we observed 2 previously undocumented aspects of asexual reproduction in E. lineata: (1) the parasitic stage undergoes transverse fission via physal pinching, the first report of asexual reproduction in a pre-adult stage in the Edwardsiidae; and (2) the juvenile polyp undergoes transverse fission via polarity reversal, the first time this form of fission has been reported in E. lineata.

Is it the Earth that turns or the Sun that goes behind the mountains? Students' misconceptions about the day/night cycle after reading a science text

NASA Astrophysics Data System (ADS)

Vosniadou, Stella; Skopeliti, Irini

2017-10-01

The present research tested the hypothesis that the reading of science text can create new misconceptions in students with incongruent prior knowledge, and that these new misconceptions will be similar to the fragmented and synthetic conceptions obtained in prior developmental research. Ninety-nine third- and fifth-grade children read and recalled one of two texts that provided scientific or phenomenal explanations of the day/night cycle. All the participants gave explanations of the phenomenon in question prior to reading one of the texts and after they read it. The results showed that the participants who provided explanations of the day/night cycle at pretest incongruent with the scientific explanation recalled less information and generated more invalid inferences. An analysis of the participants' posttest explanations indicated that these readers formed new misconceptions similar to the fragmented and synthetic conceptions obtained in developmental research. The implications of the above for text comprehension and science education research are discussed.

Annotation: Early Intervention and Prevention of Self-Injurious Behaviour Exhibited by Young Children with Developmental Disabilities

ERIC Educational Resources Information Center

Richman, D. M.

2008-01-01

The ontogeny of self-injurious behaviour exhibited by young children with developmental delays or disabilities is due to a complex interaction between neurobiological and environmental variables. In this manuscript, the literature on emerging self-injury in the developmental disability population is reviewed with a focus on an operant conceptual…

Cell Migration Analysis: A Low-Cost Laboratory Experiment for Cell and Developmental Biology Courses Using Keratocytes from Fish Scales

ERIC Educational Resources Information Center

Prieto, Daniel; Aparicio, Gonzalo; Sotelo-Silveira, Jose R.

2017-01-01

Cell and developmental processes are complex, and profoundly dependent on spatial relationships that change over time. Innovative educational or teaching strategies are always needed to foster deep comprehension of these processes and their dynamic features. However, laboratory exercises in cell and developmental biology at the undergraduate level…

Mutations in CENPE define a novel kinetochore-centromeric mechanism for Microcephalic Primordial Dwarfism

PubMed Central

Mirzaa, Ghayda M.; Vitre, Benjamin; Carpenter, Gillian; Abramowicz, Iga; Gleeson, Joseph G.; Paciorkowski, Alex R.; Cleveland, Don W.; Dobyns, William B.; O’Driscoll, Mark

2015-01-01

Defects in centrosome, centrosomal-associated and spindle-associated proteins are the most frequent cause of Primary Microcephaly (PM) and Microcephalic Primordial Dwarfism (MPD) syndromes in humans. Mitotic progression and segregation defects, microtubule spindle abnormalities and impaired DNA damage-induced G2-M cell cycle checkpoint proficiency have been documented in cell lines from these patients. This suggests that impaired mitotic entry, progression and exit strongly contribute to PM and MPD. Considering the vast protein networks involved in coordinating this cell cycle stage, the list of potential target genes that could underlie novel developmental disorders is large. One such complex network, with a direct microtubule-mediated physical connection to the centrosome, is the kinetochore. This centromeric-associated structure nucleates microtubule attachments onto mitotic chromosomes. Here, we described novel compound heterozygous variants in CENPE in two siblings who exhibit a profound MPD associated with developmental delay, simplified gyri and other isolated abnormalities. CENPE encodes centromere-associated protein E (CENP-E), a core kinetochore component functioning to mediate chromosome congression initially of misaligned chromosomes and in subsequent spindle microtubule capture during mitosis. Firstly, we present a comprehensive clinical description of these patients. Then, using patient cells we document abnormalities in spindle microtubule organisation, mitotic progression and segregation, before modeling the cellular pathogenicity of these variants in an independent cell system. Our cellular analysis shows that a pathogenic defect in CENP-E, a kinetochore-core protein, largely phenocopies PCNT-mutated Microcephalic Osteodysplastic Primordial Dwarfism type II patient cells. PCNT encodes a centrosome-associated protein. These results highlight a common underlying pathomechanism. Our findings provide the first evidence for a kinetochore-based route to MPD in humans. PMID:24748105

Mutations in CENPE define a novel kinetochore-centromeric mechanism for microcephalic primordial dwarfism.

PubMed

Mirzaa, Ghayda M; Vitre, Benjamin; Carpenter, Gillian; Abramowicz, Iga; Gleeson, Joseph G; Paciorkowski, Alex R; Cleveland, Don W; Dobyns, William B; O'Driscoll, Mark

2014-08-01

Defects in centrosome, centrosomal-associated and spindle-associated proteins are the most frequent cause of primary microcephaly (PM) and microcephalic primordial dwarfism (MPD) syndromes in humans. Mitotic progression and segregation defects, microtubule spindle abnormalities and impaired DNA damage-induced G2-M cell cycle checkpoint proficiency have been documented in cell lines from these patients. This suggests that impaired mitotic entry, progression and exit strongly contribute to PM and MPD. Considering the vast protein networks involved in coordinating this cell cycle stage, the list of potential target genes that could underlie novel developmental disorders is large. One such complex network, with a direct microtubule-mediated physical connection to the centrosome, is the kinetochore. This centromeric-associated structure nucleates microtubule attachments onto mitotic chromosomes. Here, we described novel compound heterozygous variants in CENPE in two siblings who exhibit a profound MPD associated with developmental delay, simplified gyri and other isolated abnormalities. CENPE encodes centromere-associated protein E (CENP-E), a core kinetochore component functioning to mediate chromosome congression initially of misaligned chromosomes and in subsequent spindle microtubule capture during mitosis. Firstly, we present a comprehensive clinical description of these patients. Then, using patient cells we document abnormalities in spindle microtubule organization, mitotic progression and segregation, before modeling the cellular pathogenicity of these variants in an independent cell system. Our cellular analysis shows that a pathogenic defect in CENP-E, a kinetochore-core protein, largely phenocopies PCNT-mutated microcephalic osteodysplastic primordial dwarfism-type II patient cells. PCNT encodes a centrosome-associated protein. These results highlight a common underlying pathomechanism. Our findings provide the first evidence for a kinetochore-based route to MPD in humans.

From big data to deep insight in developmental science.

PubMed

Gilmore, Rick O

2016-01-01

The use of the term 'big data' has grown substantially over the past several decades and is now widespread. In this review, I ask what makes data 'big' and what implications the size, density, or complexity of datasets have for the science of human development. A survey of existing datasets illustrates how existing large, complex, multilevel, and multimeasure data can reveal the complexities of developmental processes. At the same time, significant technical, policy, ethics, transparency, cultural, and conceptual issues associated with the use of big data must be addressed. Most big developmental science data are currently hard to find and cumbersome to access, the field lacks a culture of data sharing, and there is no consensus about who owns or should control research data. But, these barriers are dissolving. Developmental researchers are finding new ways to collect, manage, store, share, and enable others to reuse data. This promises a future in which big data can lead to deeper insights about some of the most profound questions in behavioral science. © 2016 The Authors. WIREs Cognitive Science published by Wiley Periodicals, Inc.

Predictors and Characteristics of Erikson's Life Cycle Model Among Men: A 32-Year Longitudinal Study

ERIC Educational Resources Information Center

Westermeyer, Jerry F.

2004-01-01

To assess Erikson's life cycle model, 86 men, initially selected for health, were prospectively studied at age 21, and reassessed 32 years later at age 53. Using the Vaillant and Milofsky (1980) modification of Erikson's model, 48 men (56%) achieved generativity, an advanced developmental stage, at follow-up. Results generally support Erikson's…

Prepupal diapause and instar IV developmental rates of the spruce beetle, Dendroctonus rufipennis (Coleoptera: Curculionidae, Scolytinae)

Treesearch

E. Matthew Hansen; Barbara J. Bentz; James A. Powell; David R. Gray; James C. Vandygriff

2011-01-01

The spruce beetle, Dendroctonus rufipennis (Kirby), is an important mortality agent of native spruces throughout North America. The life-cycle duration of this species varies from 1 to 3 years depending temperature. The univoltine cycle (one generation per year) is thought to maximize outbreak risk and accelerate host mortality in established outbreaks. Prepupal...

How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

PubMed Central

Beachy, Christopher K.; Ryan, Travis J.; Bonett, Ronald M.

2017-01-01

Plethodontid salamanders exhibit biphasic, larval form paedomorphic, and direct developing life cycles. This diversity of developmental strategies exceeds that of any other family of terrestrial vertebrate. Here we compare patterns of larval development among the three divergent lineages of biphasic plethodontids and other salamanders. We discuss how patterns of life-cycle evolution and larval ecology might have produced a wide array of larval life histories. Compared with many other salamanders, most larval plethodontids have relatively slow growth rates and sometimes exceptionally long larval periods (up to 60 mo). Recent phylogenetic analyses of life-cycle evolution indicate that ancestral plethodontids were likely direct developers. If true, then biphasic and paedomorphic lineages might have been independently derived through different developmental mechanisms. Furthermore, biphasic plethodontids largely colonized stream habitats, which tend to have lower productivity than seasonally ephemeral ponds. Consistent with this, plethodontid larvae grow very slowly, and metamorphic timing does not appear to be strongly affected by growth history. On the basis of this, we speculate that feeding schedules and stress hormones might play a comparatively reduced role in governing the timing of metamorphosis of stream-dwelling salamanders, particularly plethodontids. PMID:29269959

HIV Infection Legal Issues: An Introduction for Developmental Services. Technical Report on Developmental Disabilities and HIV Infection, Number 2.

ERIC Educational Resources Information Center

Harvey, David C.; Decker, Curtis L.

As agencies and programs serving individuals with developmental disabilities are called upon to serve a new population of individuals with human immunodeficiency virus (HIV) infection, they will be forced to confront complex legal questions. This paper discusses the legal frameworks in which individuals with HIV infection are considered eligible…

Reliability and Diagnostic Efficiency of the Diagnostic Inventory for Disharmony (DID) in Youths with Pervasive Developmental Disorder and Multiple Complex Developmental Disorder

ERIC Educational Resources Information Center

Xavier, Jean; Vannetzel, Leonard; Viaux, Sylvie; Leroy, Arthur; Plaza, Monique; Tordjman, Sylvie; Mille, Christian; Bursztejn, Claude; Cohen, David; Guile, Jean-Marc

2011-01-01

The Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) category is a psychopathological entity few have described and is poorly, and mainly negatively, defined by autism exclusion. In order to limit PDD-NOS heterogeneity, alternative clinical constructs have been developed. This study explored the reliability and the diagnostic…

Analysis of global gene expression profiles to identify differentially expressed genes critical for embryo development in Brassica rapa.

PubMed

Zhang, Yu; Peng, Lifang; Wu, Ya; Shen, Yanyue; Wu, Xiaoming; Wang, Jianbo

2014-11-01

Embryo development represents a crucial developmental period in the life cycle of flowering plants. To gain insights into the genetic programs that control embryo development in Brassica rapa L., RNA sequencing technology was used to perform transcriptome profiling analysis of B. rapa developing embryos. The results generated 42,906,229 sequence reads aligned with 32,941 genes. In total, 27,760, 28,871, 28,384, and 25,653 genes were identified from embryos at globular, heart, early cotyledon, and mature developmental stages, respectively, and analysis between stages revealed a subset of stage-specific genes. We next investigated 9,884 differentially expressed genes with more than fivefold changes in expression and false discovery rate ≤ 0.001 from three adjacent-stage comparisons; 1,514, 3,831, and 6,633 genes were detected between globular and heart stage embryo libraries, heart stage and early cotyledon stage, and early cotyledon and mature stage, respectively. Large numbers of genes related to cellular process, metabolism process, response to stimulus, and biological process were expressed during the early and middle stages of embryo development. Fatty acid biosynthesis, biosynthesis of secondary metabolites, and photosynthesis-related genes were expressed predominantly in embryos at the middle stage. Genes for lipid metabolism and storage proteins were highly expressed in the middle and late stages of embryo development. We also identified 911 transcription factor genes that show differential expression across embryo developmental stages. These results increase our understanding of the complex molecular and cellular events during embryo development in B. rapa and provide a foundation for future studies on other oilseed crops.

Comprehensive Dissection of Spatiotemporal Metabolic Shifts in Primary, Secondary, and Lipid Metabolism during Developmental Senescence in Arabidopsis1[W

PubMed Central

Watanabe, Mutsumi; Balazadeh, Salma; Tohge, Takayuki; Erban, Alexander; Giavalisco, Patrick; Kopka, Joachim; Mueller-Roeber, Bernd; Fernie, Alisdair R.; Hoefgen, Rainer

2013-01-01

Developmental senescence is a coordinated physiological process in plants and is critical for nutrient redistribution from senescing leaves to newly formed sink organs, including young leaves and developing seeds. Progress has been made concerning the genes involved and the regulatory networks controlling senescence. The resulting complex metabolome changes during senescence have not been investigated in detail yet. Therefore, we conducted a comprehensive profiling of metabolites, including pigments, lipids, sugars, amino acids, organic acids, nutrient ions, and secondary metabolites, and determined approximately 260 metabolites at distinct stages in leaves and siliques during senescence in Arabidopsis (Arabidopsis thaliana). This provided an extensive catalog of metabolites and their spatiotemporal cobehavior with progressing senescence. Comparison with silique data provides clues to source-sink relations. Furthermore, we analyzed the metabolite distribution within single leaves along the basipetal sink-source transition trajectory during senescence. Ceramides, lysolipids, aromatic amino acids, branched chain amino acids, and stress-induced amino acids accumulated, and an imbalance of asparagine/aspartate, glutamate/glutamine, and nutrient ions in the tip region of leaves was detected. Furthermore, the spatiotemporal distribution of tricarboxylic acid cycle intermediates was already changed in the presenescent leaves, and glucosinolates, raffinose, and galactinol accumulated in the base region of leaves with preceding senescence. These results are discussed in the context of current models of the metabolic shifts occurring during developmental and environmentally induced senescence. As senescence processes are correlated to crop yield, the metabolome data and the approach provided here can serve as a blueprint for the analysis of traits and conditions linking crop yield and senescence. PMID:23696093

Epigenetic regulation of adaptive responses of forest tree species to the environment

PubMed Central

Bräutigam, Katharina; Vining, Kelly J; Lafon-Placette, Clément; Fossdal, Carl G; Mirouze, Marie; Marcos, José Gutiérrez; Fluch, Silvia; Fraga, Mario Fernández; Guevara, M Ángeles; Abarca, Dolores; Johnsen, Øystein; Maury, Stéphane; Strauss, Steven H; Campbell, Malcolm M; Rohde, Antje; Díaz-Sala, Carmen; Cervera, María-Teresa

2013-01-01

Epigenetic variation is likely to contribute to the phenotypic plasticity and adaptative capacity of plant species, and may be especially important for long-lived organisms with complex life cycles, including forest trees. Diverse environmental stresses and hybridization/polyploidization events can create reversible heritable epigenetic marks that can be transmitted to subsequent generations as a form of molecular “memory”. Epigenetic changes might also contribute to the ability of plants to colonize or persist in variable environments. In this review, we provide an overview of recent data on epigenetic mechanisms involved in developmental processes and responses to environmental cues in plant, with a focus on forest tree species. We consider the possible role of forest tree epigenetics as a new source of adaptive traits in plant breeding, biotechnology, and ecosystem conservation under rapid climate change. PMID:23467802

Developmental trends in the process of constructing own- and other-race facial composites.

PubMed

Kehn, Andre; Renken, Maggie D; Gray, Jennifer M; Nunez, Narina L

2014-01-01

The current study examined developmental differences from the age of 5 to 18 in the creation process of own- and other-race facial composites. In addition, it considered how differences in the creation process affect similarity ratings. Participants created two composites (one own- and one other-race) from memory. The complexity of the composite creation process was recorded during Phase One. In Phase Two, a separate group of participants rated the composites for similarity to the corresponding target face. Results support the cross-race effect, developmental differences (based on composite creators) in similarity ratings, and the importance of the creation process for own- and other-race facial composites. Together, these findings suggest that as children get older the process through which they create facial composites becomes more complex and their ability to create facial composites improves. Increased complexity resulted in higher rated composites. Results are discussed from a psycho-legal perspective.

Plants: Novel Developmental Processes.

ERIC Educational Resources Information Center

Goldberg, Robert B.

1988-01-01

Describes the diversity of plants. Outlines novel developmental and complex genetic processes that are specific to plants. Identifies approaches that can be used to solve problems in plant biology. Cites the advantages of using higher plants for experimental systems. (RT)

Gene Expression Profiles in Rice Developing Ovules Provided Evidence for the Role of Sporophytic Tissue in Female Gametophyte Development.

PubMed

Wu, Ya; Yang, Liyu; Cao, Aqin; Wang, Jianbo

2015-01-01

The development of ovule in rice (Oryza sativa) is vital during its life cycle. To gain more understanding of the molecular events associated with the ovule development, we used RNA sequencing approach to perform transcriptome-profiling analysis of the leaf and ovules at four developmental stages. In total, 25,401, 23,343, 23,647 and 23,806 genes were identified from the four developmental stages of the ovule, respectively. We identified a number of differently expressed genes (DEGs) from three adjacent stage comparisons, which may play crucial roles in ovule development. The DEGs were then conducted functional annotations and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses. Genes related to cellular component biogenesis, membrane-bounded organelles and reproductive regulation were identified to be highly expressed during the ovule development. Different expression levels of auxin-related and cytokinin-related genes were also identified at various stages, providing evidence for the role of sporophytic ovule tissue in female gametophyte development from the aspect of gene expression. Generally, an overall transcriptome analysis for rice ovule development has been conducted. These results increased our knowledge of the complex molecular and cellular events that occur during the development of rice ovule and provided foundation for further studies on rice ovule development.

The developmental transcriptome atlas of the spoon worm Urechis unicinctus (Echiurida: Annelida).

PubMed

Park, Chungoo; Han, Yong-Hee; Lee, Sung-Gwon; Ry, Kyoung-Bin; Oh, Jooseong; Kern, Elizabeth M A; Park, Joong-Ki; Cho, Sung-Jin

2018-03-01

Echiurida is one of the most intriguing major subgroups of annelida because, unlike most other annelids, echiurids lack metameric body segmentation as adults. For this reason, transcriptome analyses from various developmental stages of echiurid species can be of substantial value for understanding precise expression levels and the complex regulatory networks during early and larval development. A total of 914 million raw RNA-Seq reads were produced from 14 developmental stages of Urechis unicinctus and were de novo assembled into contigs spanning 63,928,225 bp with an N50 length of 2700 bp. The resulting comprehensive transcriptome database of the early developmental stages of U. unicinctus consists of 20,305 representative functional protein-coding transcripts. Approximately 66% of unigenes were assigned to superphylum-level taxa, including Lophotrochozoa (40%). The completeness of the transcriptome assembly was assessed using benchmarking universal single-copy orthologs; 75.7% of the single-copy orthologs were presented in our transcriptome database. We observed 3 distinct patterns of global transcriptome profiles from 14 developmental stages and identified 12,705 genes that showed dynamic regulation patterns during the differentiation and maturation of U. unicinctus cells. We present the first large-scale developmental transcriptome dataset of U. unicinctus and provide a general overview of the dynamics of global gene expression changes during its early developmental stages. The analysis of time-course gene expression data is a first step toward understanding the complex developmental gene regulatory networks in U. unicinctus and will furnish a valuable resource for analyzing the functions of gene repertoires in various developmental phases.

Application of Caenorhabditis elegans (nematode) and Danio rerio embryo (zebrafish) as model systems to screen for developmental and reproductive toxicity of Piperazine compounds.

PubMed

Racz, Peter I; Wildwater, Marjolein; Rooseboom, Martijn; Kerkhof, Engelien; Pieters, Raymond; Yebra-Pimentel, Elena Santidrian; Dirks, Ron P; Spaink, Herman P; Smulders, Chantal; Whale, Graham F

2017-10-01

To enable selection of novel chemicals for new processes, there is a recognized need for alternative toxicity screening assays to assess potential risks to man and the environment. For human health hazard assessment these screening assays need to be translational to humans, have high throughput capability, and from an animal welfare perspective be harmonized with the principles of the 3Rs (Reduction, Refinement, Replacement). In the area of toxicology a number of cell culture systems are available but while these have some predictive value, they are not ideally suited for the prediction of developmental and reproductive toxicology (DART). This is because they often lack biotransformation capacity, multicellular or multi- organ complexity, for example, the hypothalamus pituitary gonad (HPG) axis and the complete life cycle of whole organisms. To try to overcome some of these limitations in this study, we have used Caenorhabditis elegans (nematode) and Danio rerio embryos (zebrafish) as alternative assays for DART hazard assessment of some candidate chemicals being considered for a new commercial application. Nematodes exposed to Piperazine and one of the analogs tested showed a slight delay in development compared to untreated animals but only at high concentrations and with Piperazine as the most sensitive compound. Total brood size of the nematodes was also reduced primarily by Piperazine and one of the analogs. In zebrafish Piperazine and analogs showed developmental delays. Malformations and mortality in individual fish were also scored. Significant malformations were most sensitively identified with Piperazine, significant mortality was only observed in Piperazine and only at the higest dose. Thus, Piperazine seemed the most toxic compound for both nematodes and zebrafish. The results of the nematode and zebrafish studies were in alignment with data obtained from conventional mammalian toxicity studies indicating that these have potential as developmental toxicity screening systems. The results of these studies also provided reassurance that none of the Piperazines tested are likely to have any significant developmental and/or reproductive toxicity issues to humans when used in their commercial applications. Copyright © 2017. Published by Elsevier Ltd.

The CAESAR models for developmental toxicity

EPA Science Inventory

The new REACH legislation requires assessment of a high number of chemicals in the European market for several endpoints. Developmental Toxicity results amongst the most difficult endpoint to assess, due to the complexity, length and costs of experiments. Following the encouragem...

Adolescent development and risk of injury: Using developmental science to improve interventions

PubMed Central

Johnson, Sara B.; Jones, Vanya C.

2015-01-01

In adolescence, there is a complex interaction among physical, cognitive, and psychosocial developmental processes, culminating in greater risk-taking and novelty-seeking. Concurrently, adolescents face an increasingly demanding environment, which results in heightened vulnerability to injury. In this paper, we provide an overview of developmental considerations for adolescent injury interventions based on developmental science including findings from behavioral neuroscience and psychology. We examine the role that typical developmental processes play in the way adolescents perceive and respond to risk and how this integrated body of developmental research adds to our understanding of how to do injury prevention with adolescents. We then highlight strategies to improve the translation of developmental research into adolescent injury prevention practice, calling on examples of existing interventions including graduated driver licensing. PMID:20876765

Brain evolution and development: adaptation, allometry and constraint

PubMed Central

Barton, Robert A.

2016-01-01

Phenotypic traits are products of two processes: evolution and development. But how do these processes combine to produce integrated phenotypes? Comparative studies identify consistent patterns of covariation, or allometries, between brain and body size, and between brain components, indicating the presence of significant constraints limiting independent evolution of separate parts. These constraints are poorly understood, but in principle could be either developmental or functional. The developmental constraints hypothesis suggests that individual components (brain and body size, or individual brain components) tend to evolve together because natural selection operates on relatively simple developmental mechanisms that affect the growth of all parts in a concerted manner. The functional constraints hypothesis suggests that correlated change reflects the action of selection on distributed functional systems connecting the different sub-components, predicting more complex patterns of mosaic change at the level of the functional systems and more complex genetic and developmental mechanisms. These hypotheses are not mutually exclusive but make different predictions. We review recent genetic and neurodevelopmental evidence, concluding that functional rather than developmental constraints are the main cause of the observed patterns. PMID:27629025

Molecular cloning, developmental expression, and cellular localization of the 70-kDa RPA-1 subunit of Drosophila melanogaster.

PubMed

Perdigão, J; Logarinho, E; Avides, M C; Sunkel, C E

1999-12-01

Replication protein A (RPA) is a highly conserved multifunctional heterotrimeric complex, involved in DNA replication, repair, recombination, and possibly transcription. Here, we report the cloning of the gene that codes for the largest subunit of the Drosophila melanogaster RPA homolog, dmRPA70. In situ hybridization showed that dmRPA70 RNA is present in developing embryos during the first 16 cycles. After this point, dm-RPA70 expression is downregulated in cells that enter a G1 phase and exit the mitotic cycle, becoming restricted to brief bursts of accumulation from late G1 to S phase. This pattern of regulated expression is also observed in the developing eye imaginal disc. In addition, we have shown that the presence of cyclin E is necessary and sufficient to drive the expression of dmRPA70 in embryonic cells arrested in G1 but is not required in tissues undergoing endoreduplication. Immunolocalization showed that in early developing embryos, the dmRPA70 protein associates with chromatin from the end of mitosis until the beginning of the next prophase in a dynamic speckled pattern that is strongly suggestive of its association with replication foci.

Estuarine retention of larvae of the crab Rhithropanopeus harrisii

NASA Astrophysics Data System (ADS)

Cronin, Thomas W.

1982-08-01

Larvae of estuarine organisms continually face possible export from the parent estuary. Retention of larvae of the estuarine crab Rhithropanopeus harrisii was investigated in the upper Newport River estuary, North Carolina. All of the developmental stages occurred in the same area of the estuary with similar horizontal distributions, and the concentrations of intermediate and late stages were not greatly reduced from those of the first larval stage. This was strong evidence for the continuous retention of larvae in the upper estuary. To determine mechanisms by which retention might be effected, field studies of the vertical distributions and migrations of these larvae were made. The four zoeal stages had similar but complex vertical migration patterns, which varied from study to study. These migrations centered on the depth of no net flow, reducing longitudinal transport during development. Cross-spectral analysis of the larval migrations and the environmental cycles of light, salinity and current speed revealed that each of these external cycles affected larval depth. Megalopae of R. harrisii also migrated vertically, but they were present in much lower concentrations than the zoeal stages, an indication of a change to benthic existence in this final larval form.

Biological and psychological rhythms: an integrative approach to rhythm disturbances in autistic disorder.

PubMed

Botbol, Michel; Cabon, Philippe; Kermarrec, Solenn; Tordjman, Sylvie

2013-09-01

Biological rhythms are crucial phenomena that are perfect examples of the adaptation of organisms to their environment. A considerable amount of work has described different types of biological rhythms (from circadian to ultradian), individual differences in their patterns and the complexity of their regulation. In particular, the regulation and maturation of the sleep-wake cycle have been thoroughly studied. Its desynchronization, both endogenous and exogenous, is now well understood, as are its consequences for cognitive impairments and health problems. From a completely different perspective, psychoanalysts have shown a growing interest in the rhythms of psychic life. This interest extends beyond the original focus of psychoanalysis on dreams and the sleep-wake cycle, incorporating central theoretical and practical psychoanalytic issues related to the core functioning of the psychic life: the rhythmic structures of drive dynamics, intersubjective developmental processes and psychic containment functions. Psychopathological and biological approaches to the study of infantile autism reveal the importance of specific biological and psychological rhythmic disturbances in this disorder. Considering data and hypotheses from both perspectives, this paper proposes an integrative approach to the study of these rhythmic disturbances and offers an etiopathogenic hypothesis based on this integrative approach. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Knockout Screen of ApiAP2 Genes Reveals Networks of Interacting Transcriptional Regulators Controlling the Plasmodium Life Cycle.

PubMed

Modrzynska, Katarzyna; Pfander, Claudia; Chappell, Lia; Yu, Lu; Suarez, Catherine; Dundas, Kirsten; Gomes, Ana Rita; Goulding, David; Rayner, Julian C; Choudhary, Jyoti; Billker, Oliver

2017-01-11

A family of apicomplexa-specific proteins containing AP2 DNA-binding domains (ApiAP2s) was identified in malaria parasites. This family includes sequence-specific transcription factors that are key regulators of development. However, functions for the majority of ApiAP2 genes remain unknown. Here, a systematic knockout screen in Plasmodium berghei identified ten ApiAP2 genes that were essential for mosquito transmission: four were critical for the formation of infectious ookinetes, and three were required for sporogony. We describe non-essential functions for AP2-O and AP2-SP proteins in blood stages, and identify AP2-G2 as a repressor active in both asexual and sexual stages. Comparative transcriptomics across mutants and developmental stages revealed clusters of co-regulated genes with shared cis promoter elements, whose expression can be controlled positively or negatively by different ApiAP2 factors. We propose that stage-specific interactions between ApiAP2 proteins on partly overlapping sets of target genes generate the complex transcriptional network that controls the Plasmodium life cycle. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Trans-methylation reactions in plants: focus on the activated methyl cycle.

PubMed

Rahikainen, Moona; Alegre, Sara; Trotta, Andrea; Pascual, Jesús; Kangasjärvi, Saijaliisa

2018-02-01

Trans-methylation reactions are vital in basic metabolism, epigenetic regulation, RNA metabolism, and posttranslational control of protein function and therefore fundamental in determining the physiological processes in all living organisms. The plant kingdom is additionally characterized by the production of secondary metabolites that undergo specific hydroxylation, oxidation and methylation reactions to obtain a wide array of different chemical structures. Increasing research efforts have started to reveal the enzymatic pathways underlying the biosynthesis of complex metabolites in plants. Further engineering of these enzymatic machineries offers significant possibilities in the development of bio-based technologies, but necessitates deep understanding of their potential metabolic and regulatory interactions. Trans-methylation reactions are tightly coupled with the so-called activated methyl cycle (AMC), an essential metabolic circuit that maintains the trans-methylation capacity in all living cells. Tight regulation of the AMC is crucial in ensuring accurate trans-methylation reactions in different subcellular compartments, cell types, developmental stages and environmental conditions. This review addresses the organization and posttranslational regulation of the AMC and elaborates its critical role in determining metabolic regulation through modulation of methyl utilization in stress-exposed plants. © 2017 Scandinavian Plant Physiology Society.

Lipid Synthesis in Protozoan Parasites: a Comparison Between Kinetoplastids and Apicomplexans

PubMed Central

Ramakrishnan, Srinivasan; Serricchio, Mauro; Striepen, Boris; Bütikofer, Peter

2013-01-01

Lipid metabolism is of crucial importance for pathogens. Lipids serve as cellular building blocks, signalling molecules, energy stores, posttranslational modifiers, and pathogenesis factors. Parasites rely on a complex system of uptake and synthesis mechanisms to satisfy their lipid needs. The parameters of this system change dramatically as the parasite transits through the various stages of its life cycle. Here we discuss the tremendous recent advances that have been made in the understanding of the synthesis and uptake pathways for fatty acids and phospholipids in apicomplexan and kinetoplastid parasites, including Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania. Lipid synthesis differs in significant ways between parasites from both phyla and the human host. Parasites have acquired novel pathways through endosymbiosis, as in the case of the apicoplast, have dramatically reshaped substrate and product profiles, and have evolved specialized lipids to interact with or manipulate the host. These differences potentially provide opportunities for drug development. We outline the lipid pathways for key species in detail as they progress through the developmental cycle and highlight those that are of particular importance to the biology of the pathogens and/or are the most promising targets for parasite-specific treatment. PMID:23827884

Cell type-specific translational repression of Cyclin B during meiosis in males.

PubMed

Baker, Catherine Craig; Gim, Byung Soo; Fuller, Margaret T

2015-10-01

The unique cell cycle dynamics of meiosis are controlled by layers of regulation imposed on core mitotic cell cycle machinery components by the program of germ cell development. Although the mechanisms that regulate Cdk1/Cyclin B activity in meiosis in oocytes have been well studied, little is known about the trans-acting factors responsible for developmental control of these factors in male gametogenesis. During meiotic prophase in Drosophila males, transcript for the core cell cycle protein Cyclin B1 (CycB) is expressed in spermatocytes, but the protein does not accumulate in spermatocytes until just before the meiotic divisions. Here, we show that two interacting proteins, Rbp4 and Fest, expressed at the onset of spermatocyte differentiation under control of the developmental program of male gametogenesis, function to direct cell type- and stage-specific repression of translation of the core G2/M cell cycle component cycB during the specialized cell cycle of male meiosis. Binding of Fest to Rbp4 requires a 31-amino acid region within Rbp4. Rbp4 and Fest are required for translational repression of cycB in immature spermatocytes, with Rbp4 binding sequences in a cell type-specific shortened form of the cycB 3' UTR. Finally, we show that Fest is required for proper execution of meiosis I. © 2015. Published by The Company of Biologists Ltd.

From big data to deep insight in developmental science

PubMed Central

2016-01-01

The use of the term ‘big data’ has grown substantially over the past several decades and is now widespread. In this review, I ask what makes data ‘big’ and what implications the size, density, or complexity of datasets have for the science of human development. A survey of existing datasets illustrates how existing large, complex, multilevel, and multimeasure data can reveal the complexities of developmental processes. At the same time, significant technical, policy, ethics, transparency, cultural, and conceptual issues associated with the use of big data must be addressed. Most big developmental science data are currently hard to find and cumbersome to access, the field lacks a culture of data sharing, and there is no consensus about who owns or should control research data. But, these barriers are dissolving. Developmental researchers are finding new ways to collect, manage, store, share, and enable others to reuse data. This promises a future in which big data can lead to deeper insights about some of the most profound questions in behavioral science. WIREs Cogn Sci 2016, 7:112–126. doi: 10.1002/wcs.1379 For further resources related to this article, please visit the WIREs website. PMID:26805777

Stress resistance strategy in an arid land shrub: interactions between developmental instability and fractal dimention

USGS Publications Warehouse

Escos, J.; Alados, C.L.; Pugnaire, F. I.; Puigdefábregas, J.; Emlen, J.

2000-01-01

This paper investigates allocation of energy to mechanisms that generate and preserve architectural forms (i.e. developmental stability, complexity of branching patterns) and productivity (growth and reproduction) in response to environmental disturbances (i.e. grazing and resource availability). The statistical error in translational symmetry was used to detect random intra-individual variability during development. This can be thought of as a measure of developmental instability caused by stress. Additionally, we use changes in fractal complexity and shoot distribution of branch structures as an alternate indicator of stress. These methods were applied to Anthyllis cytisoides L., a semi-arid environment shrub, to ascertain the effect of grazing and slope exposure on developmental traits in a 2×2 factorial design. The results show that A. cytisoidesmaintains developmental stability at the expense of productivity. Anthyllis cytisoides was developmentally more stable when grazed and when on south-facing, as opposed to north-facing slopes. On the contrary, shoot length, leaf area, fractal dimension and reproductive-to-vegetative allocation ratio were larger in north- than in south-facing slopes. As a consequence, under extreme xeric conditions, shrub mortality increased in north-facing slopes, especially when not grazed. The removal of transpiring area and the reduction of plant competition favoured developmental stability and survival in grazed plants. Differences between grazed and ungrazed plants were most evident in more mesic (north-facing) areas.

A single cyclin–CDK complex is sufficient for both mitotic and meiotic progression in fission yeast

PubMed Central

Gutiérrez-Escribano, Pilar; Nurse, Paul

2015-01-01

The dominant model for eukaryotic cell cycle control proposes that cell cycle progression is driven by a succession of CDK complexes with different substrate specificities. However, in fission yeast it has been shown that a single CDK complex generated by the fusion of the Cdc13 cyclin with the CDK protein Cdc2 can drive the mitotic cell cycle. Meiosis is a modified cell cycle programme in which a single S-phase is followed by two consecutive rounds of chromosome segregation. Here we systematically analyse the requirements of the different fission yeast cyclins for meiotic cell cycle progression. We also show that a single Cdc13–Cdc2 complex, in the absence of the other cyclins, can drive the meiotic cell cycle. We propose that qualitatively different CDK complexes are not absolutely required for cell cycle progression either during mitosis or meiosis, and that a single CDK complex can drive both cell cycle programmes. PMID:25891897

Streptomyces exploration is triggered by fungal interactions and volatile signals.

PubMed

Jones, Stephanie E; Ho, Louis; Rees, Christiaan A; Hill, Jane E; Nodwell, Justin R; Elliot, Marie A

2017-01-03

It has long been thought that the life cycle of Streptomyces bacteria encompasses three developmental stages: vegetative hyphae, aerial hyphae and spores. Here, we show interactions between Streptomyces and fungi trigger a previously unobserved mode of Streptomyces development. We term these Streptomyces cells 'explorers', for their ability to adopt a non-branching vegetative hyphal conformation and rapidly transverse solid surfaces. Fungi trigger Streptomyces exploratory growth in part by altering the composition of the growth medium, and Streptomyces explorer cells can communicate this exploratory behaviour to other physically separated streptomycetes using an airborne volatile organic compound (VOC). These results reveal that interkingdom interactions can trigger novel developmental behaviours in bacteria, here, causing Streptomyces to deviate from its classically-defined life cycle. Furthermore, this work provides evidence that VOCs can act as long-range communication signals capable of propagating microbial morphological switches.

48 CFR 201.603-2 - Selection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the following disciplines: accounting, business finance, law, contracts, purchasing, economics... additional requirements, based on the dollar value and complexity of the contracts awarded or administered in... appointed to a 3-year developmental position. Information on developmental opportunities is contained in DoD...

48 CFR 201.603-2 - Selection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the following disciplines: accounting, business finance, law, contracts, purchasing, economics... additional requirements, based on the dollar value and complexity of the contracts awarded or administered in... appointed to a 3-year developmental position. Information on developmental opportunities is contained in DoD...

48 CFR 201.603-2 - Selection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the following disciplines: accounting, business finance, law, contracts, purchasing, economics... additional requirements, based on the dollar value and complexity of the contracts awarded or administered in... appointed to a 3-year developmental position. Information on developmental opportunities is contained in DoD...

48 CFR 201.603-2 - Selection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the following disciplines: accounting, business finance, law, contracts, purchasing, economics... additional requirements, based on the dollar value and complexity of the contracts awarded or administered in... appointed to a 3-year developmental position. Information on developmental opportunities is contained in DoD...

Cytological cycles and fates in Psidium myrtoides are altered towards new cell metabolism and functionalities by the galling activity of Nothotrioza myrtoidis.

PubMed

Carneiro, R G S; Isaias, R M S

2015-03-01

The morphogenesis of galls occurs by the redifferentiation of cells that assume new functions in the modified host plant organs. The redifferentiated cells in the galls of Nothotrioza myrtoidis on Psidium myrtoides have low complexity metabolism and are photosynthesis-deficient. These galls were studied in search for evidences of the establishment of new cell cycles and fates and cytological gradients that corroborate their metabolic profile. Young and mature leaves of P. myrtoides and leaf galls induced by N. myrtoidis at different developmental stages were collected along 24 months and analyzed under light and transmission electron microscopy. The leaves of P. myrtoides are long-lasting and did not senesce within the analyzed period, while the galls have a shorter cycle, and senesce within 1 year. A homogenous parenchyma is established by a "standby-redifferentiation" of the chlorophyllous tissues, and sclerenchyma cells redifferentiate from parenchyma cells in the outer cortex of the mature galls. The lack of organelles, the underdeveloped lamellation of chloroplasts, and the occurrence of few plastoglobules are related to the photosynthetic deficiency of the galls. No cytological gradients were observed, but the organelle-rich cells of the vascular and perivascular parenchymas are similar to those of the nutritive tissues of galls induced by other insect taxa. These cells nearest to the feeding sites of N. myrtoidis present higher metabolism and well-developed apparatus for the prevention of oxidative stress. The features herein described corroborate the low metabolic profile of the galls as the cell cycles and fates of P. myrtoides are manipulated for completely new functionalities.

Hair growth induction by substance P.

PubMed

Paus, R; Heinzelmann, T; Schultz, K D; Furkert, J; Fechner, K; Czarnetzki, B M

1994-07-01

In vitro, some neuropeptides, including the tachykinin, substance P (SP), act as growth factors. The cyclic growth of the richly innervated hair follicle offers a model for probing such functions in a complex, developmentally regulated tissue interaction system under physiologic conditions. Dissecting the role of neuropeptides in this system may also reveal as yet obscure neural mechanisms of hair growth control. The neuropeptide-releasing neurotoxin, capsaicin was injected intradermally, or SP slow-release formulations were implanted subcutaneously in the back skin of C57BL/6 mice with all follicles in the resting stage of the hair cycle (telogen) in order to see whether this induced hair growth (anagen). In addition, the endogenous SP skin concentration and the activity of the main SP-degrading enzyme, neutral endopeptidase, were determined during the induced murine hair cycle by high performance liquid chromatography-controlled radioimmuno-assay (SP) or by fluorometry (neutral endopeptidase). Both capsaicin and SP induced significant hair growth (anagen) in the back skin of telogen mice. This was associated with substantial mast cell degranulation. The endogenous SP skin concentration showed significant, hair cycle-dependent fluctuations during the induced murine hair cycle, which were largely independent of the activity of neutral endopeptidase. SP may play a role in the neural control of hair growth. Whereas this pilot study does not address the underlying mechanisms of action, it demonstrates that SP has potential as a hair growth-stimulatory agent in vivo, and serves as a basis for exploring the role of tachykinins in epithelial-mesenchymal-neuroectodermal interaction systems like the hair follicle.

How can mortality increase population size? A test of two mechanistic hypotheses.

PubMed

McIntire, Kristina M; Juliano, Steven A

2018-05-03

Overcompensation occurs when added mortality increases survival to the next life-cycle stage. Overcompensation can contribute to the Hydra Effect, wherein added mortality increases equilibrium population size. One hypothesis for overcompensation is that added mortality eases density-dependence, increasing survival to adulthood ("temporal separation of mortality and density dependence"). Mortality early in the life cycle is therefore predicted to cause overcompensation, whereas mortality later in the life cycle is not. Another hypothesis for overcompensation is that threat of mortality (e.g., from predation) causes behavioral changes that reduce overexploitation of resources, allowing resource recovery, and increasing production of adults ("prudent resource exploitation"). Behaviorally active predation cues alone are therefore predicted to cause overcompensation. We tested these predictions in two experiments with larvae of two species of Aedes. As predicted, early mortality yielded greater production of adults, and of adult females, and greater estimated rate of population increase than did later mortality. Addition of water-borne predation cues usually reduced browsing on surfaces in late-stage larvae, but contrary to prediction, resulted in neither significantly greater production of adult mosquitoes nor significantly greater estimated rate of increase. Thus we have strong evidence that timing of mortality contributes to overcompensation and the Hydra effect in mosquitoes. Evidence that predation cues alone can result in overcompensation via prudent resource exploitation is lacking. We expect the overcompensation in response to early mortality will be common in organisms with complex life cycles, density dependence among juveniles, and developmental control of populations. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Structural and functional characterization of the PNKP–XRCC4–LigIV DNA repair complex

DOE PAGES

Aceytuno, R.  Daniel; Piett, Cortt G.; Havali-Shahriari, Zahra; ...

2017-04-27

Non-homologous end joining (NHEJ) repairs DNA double strand breaks in non-cycling eukaryotic cells. NHEJ relies on polynucleotide kinase/phosphatase (PNKP), which generates 5'-phosphate/3'-hydroxyl DNA termini that are critical for ligation by the NHEJ DNA ligase, LigIV. PNKP and LigIV require the NHEJ scaffolding protein, XRCC4. The PNKP FHA domain binds to the CK2-phosphorylated XRCC4 C-terminal tail, while LigIV uses its tandem BRCT repeats to bind the XRCC4 coiled-coil. Yet, the assembled PNKP-XRCC4-LigIV complex remains uncharacterized. Here, we report purification and characterization of a recombinant PNKP-XRCC4-LigIV complex. We show that the stable binding of PNKP in this complex requires XRCC4 phosphorylation andmore » that only one PNKP protomer binds per XRCC4 dimer. Small angle X-ray scattering (SAXS) reveals a flexiblemultistate complex that suggests that both the PNKP FHA and catalytic domains contact the XRCC4 coiled-coil and LigIV BRCT repeats. Hydrogen-deuterium exchange indicates protection of a surface on the PNKP phosphatase domain that may contact XRCC4-LigIV. Amutation on this surface (E326K) causes the hereditary neuro-developmental disorder, MCSZ. This mutation impairs PNKP recruitment to damaged DNA in human cells and provides a possible disease mechanism. Together, this work unveils multipoint contacts between PNKP and XRCC4-LigIV that regulate PNKP recruitment and activity within NHEJ.« less

Structural and functional characterization of the PNKP–XRCC4–LigIV DNA repair complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aceytuno, R.  Daniel; Piett, Cortt G.; Havali-Shahriari, Zahra

Non-homologous end joining (NHEJ) repairs DNA double strand breaks in non-cycling eukaryotic cells. NHEJ relies on polynucleotide kinase/phosphatase (PNKP), which generates 5'-phosphate/3'-hydroxyl DNA termini that are critical for ligation by the NHEJ DNA ligase, LigIV. PNKP and LigIV require the NHEJ scaffolding protein, XRCC4. The PNKP FHA domain binds to the CK2-phosphorylated XRCC4 C-terminal tail, while LigIV uses its tandem BRCT repeats to bind the XRCC4 coiled-coil. Yet, the assembled PNKP-XRCC4-LigIV complex remains uncharacterized. Here, we report purification and characterization of a recombinant PNKP-XRCC4-LigIV complex. We show that the stable binding of PNKP in this complex requires XRCC4 phosphorylation andmore » that only one PNKP protomer binds per XRCC4 dimer. Small angle X-ray scattering (SAXS) reveals a flexiblemultistate complex that suggests that both the PNKP FHA and catalytic domains contact the XRCC4 coiled-coil and LigIV BRCT repeats. Hydrogen-deuterium exchange indicates protection of a surface on the PNKP phosphatase domain that may contact XRCC4-LigIV. Amutation on this surface (E326K) causes the hereditary neuro-developmental disorder, MCSZ. This mutation impairs PNKP recruitment to damaged DNA in human cells and provides a possible disease mechanism. Together, this work unveils multipoint contacts between PNKP and XRCC4-LigIV that regulate PNKP recruitment and activity within NHEJ.« less

microRNA profiling in the zoonotic parasite Echinococcus canadensis using a high-throughput approach.

PubMed

Macchiaroli, Natalia; Cucher, Marcela; Zarowiecki, Magdalena; Maldonado, Lucas; Kamenetzky, Laura; Rosenzvit, Mara Cecilia

2015-02-06

microRNAs (miRNAs), a class of small non-coding RNAs, are key regulators of gene expression at post-transcriptional level and play essential roles in fundamental biological processes such as development and metabolism. The particular developmental and metabolic characteristics of cestode parasites highlight the importance of studying miRNA gene regulation in these organisms. Here, we perform a comprehensive analysis of miRNAs in the parasitic cestode Echinococcus canadensis G7, one of the causative agents of the neglected zoonotic disease cystic echinococcosis. Small RNA libraries from protoscoleces and cyst walls of E. canadensis G7 and protoscoleces of E. granulosus sensu stricto G1 were sequenced using Illumina technology. For miRNA prediction, miRDeep2 core algorithm was used. The output list of candidate precursors was manually curated to generate a high confidence set of miRNAs. Differential expression analysis of miRNAs between stages or species was estimated with DESeq. Expression levels of selected miRNAs were validated using poly-A RT-qPCR. In this study we used a high-throughput approach and found transcriptional evidence of 37 miRNAs thus expanding the miRNA repertoire of E. canadensis G7. Differential expression analysis showed highly regulated miRNAs between life cycle stages, suggesting a role in maintaining the features of each developmental stage or in the regulation of developmental timing. In this work we characterize conserved and novel Echinococcus miRNAs which represent 30 unique miRNA families. Here we confirmed the remarkable loss of conserved miRNA families in E. canadensis, reflecting their low morphological complexity and high adaptation to parasitism. We performed the first in-depth study profiling of small RNAs in the zoonotic parasite E. canadensis G7. We found that miRNAs are the preponderant small RNA silencing molecules, suggesting that these small RNAs could be an essential mechanism of gene regulation in this species. We also identified both parasite specific and divergent miRNAs which are potential biomarkers of infection. This study will provide valuable information for better understanding of the complex biology of this parasite and could help to find new potential targets for therapy and/or diagnosis.

Developmental stage-specific regulation of the circadian clock by temperature in zebrafish.

PubMed

Lahiri, Kajori; Froehlich, Nadine; Heyd, Andreas; Foulkes, Nicholas S; Vallone, Daniela

2014-01-01

The circadian clock enables animals to adapt their physiology and behaviour in anticipation of the day-night cycle. Light and temperature represent two key environmental timing cues (zeitgebers) able to reset this mechanism and so maintain its synchronization with the environmental cycle. One key challenge is to unravel how the regulation of the clock by zeitgebers matures during early development. The zebrafish is an ideal model for studying circadian clock ontogeny since the process of development occurs ex utero in an optically transparent chorion and many tools are available for genetic analysis. However, the role played by temperature in regulating the clock during zebrafish development is poorly understood. Here, we have established a clock-regulated luciferase reporter transgenic zebrafish line (Tg (-3.1) per1b::luc) to study the effects of temperature on clock entrainment. We reveal that under complete darkness, from an early developmental stage onwards (48 to 72 hpf), exposure to temperature cycles is a prerequisite for the establishment of self-sustaining rhythms of zfper1b, zfaanat2, and zfirbp expression and also for circadian cell cycle rhythms. Furthermore, we show that following the 5-9 somite stage, the expression of zfper1b is regulated by acute temperature shifts.

Effects of developmental training of basketball cadets realised in the competitive period.

PubMed

Trninić, S; Marković, G; Heimer, S

2001-12-01

The analysis of effects of a two-month developmental training cycle realised within a basketball season revealed statistically significant positive changes at the multivariate level in components of motor-functional conditioning (fitness) status of the sample of talented basketball cadets (15-16 years). The greatest correlations with discriminant function were found in variables with statistically significant changes at the univariate level, more explicitly in variables of explosive and repetitive power of the upper body and trunk, anaerobic lactic endurance, as well as in jumping type explosive leg power. The presented developmental conditioning training programme, although implemented within the competitive period, induced multiple positive fitness effects between the two control time points in this sample of basketball players. The authors suggest that, to assess power of shoulders and upper back, the test overgrip pull-up should not be applied to basketball players of this age due to its poor sensitivity. Instead, they propose the undergrip pull-up test, which is a facilitated version of the same test. The results presented in this article reinforce experienced opinion of experts that, in the training process with youth teams, the developmental conditioning training programme is effectively applicable throughout the entire competitive season. The proposed training model is a system of various training procedures, operating synergistically, aimed at enhancing integral fitness (preparedness) of basketball players. Further investigations should be focused on assessing effects of both the proposed and other developmental training cycle programmes, by means of assessing and monitoring actual quality (overall performance) of players, on the one hand, and, on the other, by following-up hormonal and biochemical changes over multiple time points.

The direct support workforce in community supports to individuals with developmental disabilities: issues, implications, and promising practices.

PubMed

Hewitt, Amy; Larson, Sheryl

2007-01-01

Difficulties in finding, keeping, and ensuring the competence of the direct support workforce in community developmental disability services has long been a challenge for individuals, families, providers, and policy makers. Direct support staff recruitment, retention, and competence are widely reported as one of the most significant barriers to the sustainability, growth, and quality of community services for people with developmental disabilities (ANCOR [2001] State of the states report. Alexandria, VA: ANCOR; Colorado Department of Human Services, [2000] Response to Footnote 106 of the FY 2001 appropriations long bill: Capacity of the community services systems for persons with developmental disabilities in Colorado; Hewitt [2000] Dynamics of the workforce crisis. Presentation at the NASDDDS Fall meeting. Alexandria, VA). While long in existence, these challenges are ones of growing concern because the number of people demanding community services is increasing and the population of people from which to recruit workers is declining (Office of the Assistant Secretary for Planning and Evaluation [2006] The supply of direct support professionals serving individuals with intellectual disabilities and other developmental disabilities: Report to Congress. Washington, DC: Office of Disability, Aging and Long-Term Care Policy, ASPE, U.S. Department of Health and Human Services). As the service system moves towards consumer direction, managed care, and more noncategorical service delivery systems, the difficulties of providing for an adequate and well-prepared workforce to support people with developmental disabilities becomes more complex and multifaceted. The solutions to those challenges are also more complex. This article reviews the literature regarding the complexity of the direct support workforce crisis, the effects of this crisis on various stakeholder groups, promising practices designed to address the challenges, and the related practice and policy implications. (c) 2007 Wiley-Liss, Inc.

Integrating family work into the treatment of young people with severe and complex depression: a developmentally focused model.

PubMed

Rice, Simon; Halperin, Stephen; Blaikie, Simon; Monson, Katherine; Stefaniak, Rachel; Phelan, Mark; Davey, Christopher

2018-04-01

Although models of family intervention are clearly articulated in the child and early adolescent literature, there is less clarity regarding family intervention approaches in later adolescence and emerging adulthood. This study provides the rationale and intervention framework for a developmentally sensitive model of time-limited family work in the outpatient treatment of complex youth depression (15-25 years). Derived from current practice in the Youth Mood Clinic (YMC) at Orygen Youth Health, Melbourne, a stepped model of family intervention is discussed. YMC aims to provide comprehensive orientation, assessment and education to all families. For some, a family-based intervention, delivered either by the treating team or through the integration of a specialist family worker, offers an important adjunct in supporting the recovery of the young person. Developmental phases and challenges experienced by the young person with respect to family/caregiver involvement are discussed in the context of two case studies. A developmentally sensitive model is presented with particular attention to the developmental needs and preferences of young people. Formal evaluation of this model is required. Evaluation perspectives should include young people, caregivers, the broader family system (i.e. siblings) and the treating team (i.e. case manager, doctor and family worker) incorporating outcome measurement. Such work determines how best to apply a time-limited family-based intervention approach in strengthening family/caregiver relationships as part of the young person's recovery from severe and complex depression. © 2016 John Wiley & Sons Australia, Ltd.

Germline Transgenic Methods for Tracking Cells and Testing Gene Function during Regeneration in the Axolotl

PubMed Central

Khattak, Shahryar; Schuez, Maritta; Richter, Tobias; Knapp, Dunja; Haigo, Saori L.; Sandoval-Guzmán, Tatiana; Hradlikova, Kristyna; Duemmler, Annett; Kerney, Ryan; Tanaka, Elly M.

2013-01-01

The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cell-cycle inhibitor p16INK4a, which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible. PMID:24052945

Environmental Enteric Dysfunction: Pathogenesis, Diagnosis, and Clinical Consequences

PubMed Central

Keusch, Gerald T.; Denno, Donna M.; Black, Robert E.; Duggan, Christopher; Guerrant, Richard L.; Lavery, James V.; Nataro, James P.; Rosenberg, Irwin H.; Ryan, Edward T.; Tarr, Phillip I.; Ward, Honorine; Bhutta, Zulfiqar A.; Coovadia, Hoosen; Lima, Aldo; Ramakrishna, Balakrishnan; Zaidi, Anita K. M.; Hay Burgess, Deborah C.; Brewer, Thomas

2014-01-01

Stunting is common in young children in developing countries, and is associated with increased morbidity, developmental delays, and mortality. Its complex pathogenesis likely involves poor intrauterine and postnatal nutrition, exposure to microbes, and the metabolic consequences of repeated infections. Acquired enteropathy affecting both gut structure and function likely plays a significant role in this outcome, especially in the first few months of life, and serve as a precursor to later interactions of infection and malnutrition. However, the lack of validated clinical diagnostic criteria has limited the ability to study its role, identify causative factors, and determine cost-effective interventions. This review addresses these issues through a historical approach, and provides recommendations to define and validate a working clinical diagnosis and to guide critical research in this area to effectively proceed. Prevention of early gut functional changes and inflammation may preclude or mitigate the later adverse vicious cycle of malnutrition and infection. PMID:25305288

Endoreduplication intensity as a marker of seed developmental stage in the Fabaceae.

PubMed

Rewers, Monika; Sliwinska, Elwira

2012-12-01

Flow cytometry (FCM) can be used to study cell cycle activity in developing, mature and germinating seeds. It provides information about a seed's physiological state and therefore can be used by seed growers for assessing optimal harvest times and presowing treatments. Because an augmented proportion of 4C nuclei usually is indicative of high mitotic activity, the 4C/2C ratio is commonly used to follow the progress of seed development and germination. However, its usefulness for polysomatic (i.e., containing cells with different DNA content) seeds is questioned. Changes in cell cycle/endoreduplication activity in developing seeds of five members of the Fabaceae were studied to determine a more suitable marker of seed developmental stages for polysomatic species based on FCM measurements. Seeds of Phaseolus vulgaris, Medicago sativa, Pisum sativum, Vicia sativa, and Vicia faba var. minor were collected 20, 30, 40, 50, and 60 days after flowering (DAF), embryos were isolated and the proportion of nuclei with different DNA contents in the embryo axis and cotyledon was established. The ratios 4C/2C and (Σ>2C)/2C were calculated. Dried seeds were subjected to laboratory germination tests following international seed testing association (ISTA) rules. Additionally, the absolute nuclear DNA content was estimated in the leaves of the studied species. During seed development nuclei with DNA contents from 2C to 128C were detected; the endopolyploidy pattern depended on the species, seed organ and developmental stage. The cell cycle/endoreduplication parameters correlated negatively with genome size. The (Σ>2C)/2C ratio in the cotyledons reflected the seed developmental stage and corresponded with seed germinability. Therefore, this ratio is recommended as a marker in polysomatic seed research and production instead of the 4C/2C ratio, which does not consider the occurrence of endopolyploid cells. Copyright © 2012 International Society for Advancement of Cytometry.

Reconstruing U-Shaped Functions

ERIC Educational Resources Information Center

Werker, Janet F.; Hall, D. Geoffrey; Fais, Laurel

2004-01-01

U-shaped developmental functions, and their N-shaped cousins, have intrigued developmental psychologists for decades because they provide a compelling demonstration that development does not always entail a monotonic increase across age in a single underlying ability. Instead, the causes of development are much more complex. Indeed,…

Pediatric HIV Infection and Developmental Disabilities.

ERIC Educational Resources Information Center

Seidel, John F.

This paper presents an overview of the developmental disabilities associated with pediatric Human Immunodeficiency Virus (HIV) infection, and examines efficacious practices for assessment and intervention programming. The focus population is early childhood into school age. The paper describes the complex array of challenges presented by these…

The power of an ontology-driven developmental toxicity database for data mining and computational modeling

EPA Science Inventory

Modeling of developmental toxicology presents a significant challenge to computational toxicology due to endpoint complexity and lack of data coverage. These challenges largely account for the relatively few modeling successes using the structure–activity relationship (SAR) parad...

The Improbable State: The Prospects for a Developmental Turn in North Korea

DTIC Science & Technology

2014-09-01

more developed than South Korea. During the Japanese occupation, North Korea was built up with the most modern industrial complex in East Asia. When...political economy as Chalmers Johnson’s writings on the developmental state. Originally written in 1982, his book MITI and the Japanese Miracle...initially coined the phrase “ Japanese developmental state.”14 His argument was essentially that Japan’s system was fundamentally different from either the

Reciprocal expression of integration host factor and HU in the developmental cycle and infectivity of Legionella pneumophila.

PubMed

Morash, Michael G; Brassinga, Ann Karen C; Warthan, Michelle; Gourabathini, Poornima; Garduño, Rafael A; Goodman, Steven D; Hoffman, Paul S

2009-04-01

Legionella pneumophila is an intracellular parasite of protozoa that differentiates late in infection into metabolically dormant cysts that are highly infectious. Regulation of this process is poorly understood. Here we report that the small DNA binding regulatory proteins integration host factor (IHF) and HU are reciprocally expressed over the developmental cycle, with HU expressed during exponential phase and IHF expressed postexponentially. To assess the role of these regulatory proteins in development, chromosomal deletions were constructed. Single (ihfA or ihfB) and double deletion (Deltaihf) IHF mutants failed to grow in Acanthamoeba castellanii unless complemented in trans when expressed temporally from the ihfA promoter but not under P(tac) (isopropyl-beta-d-thiogalactopyranoside). In contrast, IHF mutants were infectious for HeLa cells, though electron microscopic examination revealed defects in late-stage cyst morphogenesis (thickened cell wall, intracytoplasmic membranes, and inclusions of poly-beta-hydroxybutyrate), and were depressed for the developmental marker MagA. Green fluorescent protein promoter fusion assays indicated that IHF and the stationary-phase sigma factor RpoS were required for full postexponential expression of magA. Finally, defects in cyst morphogenesis noted for Deltaihf mutants in HeLa cells correlated with a loss of both detergent resistance and hyperinfectivity compared with results for wild-type cysts. These studies establish IHF and HU as markers of developmental stages and show that IHF function is required for both differentiation and full virulence of L. pneumophila in natural amoebic hosts.

Establishment of spatial pattern.

PubMed

Slack, Jonathan

2014-01-01

An overview and perspective are presented of mechanisms for the development of spatial pattern in animal embryos. It is intended both for new entrants to developmental biology and for specialists in other fields, with only a basic knowledge of animal life cycles being required. The first event of pattern formation is normally the localization of a cytoplasmic determinant in the egg, either during oogenesis or post-fertilization. Following cleavage to a multicellular stage, some cells contain the determinant and others do not. The determinant confers a specific developmental pathway on the cells that contain it, often making them the source of the first extracellular signal, or inducing factor. Inducing factors often form concentration gradients to which cells respond by up or downregulating genes at various concentration thresholds. This enables an initial situation consisting of two cell states (with or without the determinant) to generate a multistate pattern. Multiple rounds of gradient signaling, interspersed with phases of morphogenetic movements, can generate a complex pattern using a small number of signals and responding genes. Development proceeds in a hierarchical manner, with broad body subdivisions being specified initially, and becoming successively subdivided to give individual organs and tissues composed of multiple cell types in a characteristic arrangement. Double gradient models can account for embryonic regulation, whereby a similarly proportioned body pattern is formed following removal of material. Processes that are involved at the later stages include the formation of repeating structures by the combination of an oscillator with a gradient, and the formation of tissues with one cell type scattered in a background of another through a process called lateral inhibition. This set of processes make up a 'developmental toolkit' which can be deployed in various sequences and combinations to generate a very wide variety of structures and cell types. © 2014 Wiley Periodicals, Inc.

Fitness and Individuality in Complex Life Cycles.

PubMed

Herron, Matthew D

2016-12-01

Complex life cycles are common in the eukaryotic world, and they complicate the question of how to define individuality. Using a bottom-up, gene-centric approach, I consider the concept of fitness in the context of complex life cycles. I analyze the fitness effects of an allele (or a trait) on different biological units within a complex life history and how these effects drive evolutionary change within populations. Based on these effects, I attempt to construct a concept of fitness that accurately predicts evolutionary change in the context of complex life cycles.

Contribution of parenting to complex syntax development in preschool children with developmental delays or typical development.

PubMed

Moody, C T; Baker, B L; Blacher, J

2018-05-10

Despite studies of how parent-child interactions relate to early child language development, few have examined the continued contribution of parenting to more complex language skills through the preschool years. The current study explored how positive and negative parenting behaviours relate to growth in complex syntax learning from child age 3 to age 4 years, for children with typical development or developmental delays (DDs). Participants were children with or without DD (N = 60) participating in a longitudinal study of development. Parent-child interactions were transcribed and coded for parenting domains and child language. Multiple regression analyses were used to identify the contribution of parenting to complex syntax growth in children with typical development or DD. Analyses supported a final model, F(9,50) = 11.90, P < .001, including a significant three-way interaction between positive parenting behaviours, negative parenting behaviours and child delay status. This model explained 68.16% of the variance in children's complex syntax at age 4. Simple two-way interactions indicated differing effects of parenting variables for children with or without DD. Results have implications for understanding of complex syntax acquisition in young children, as well as implications for interventions. © 2018 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Developmental Hypothyroxinemia and Hypothyroidism Reduce Parallel Fiber-Purkinje Cell Synapses in Rat Offspring by Downregulation of Neurexin1/Cbln1/GluD2 Tripartite Complex.

PubMed

Wang, Yuan; Dong, Jing; Wang, Yi; Wei, Wei; Song, Binbin; Shan, Zhongyan; Teng, Weiping; Chen, Jie

2016-10-01

Iodine is a significant micronutrient. Iodine deficiency (ID)-induced hypothyroxinemia and hypothyroidism during developmental period can cause cerebellar dysfunction. However, mechanisms are still unclear. Therefore, the present research aims to study effects of developmental hypothyroxinemia caused by mild ID and hypothyroidism caused by severe ID or methimazole (MMZ) on parallel fiber-Purkinje cell (PF-PC) synapses in filial cerebellum. Maternal hypothyroxinemia and hypothyroidism models were established in Wistar rats using ID diet and deionized water supplemented with different concentrations of potassium iodide or MMZ water. Birth weight and cerebellum weight were measured. We also examined PF-PC synapses using immunofluorescence, and western blot analysis was conducted to investigate the activity of Neurexin1/cerebellin1 (Cbln1)/glutamate receptor d2 (GluD2) tripartite complex. Our results showed that hypothyroxinemia and hypothyroidism decreased birth weight and cerebellum weight and reduced the PF-PC synapses on postnatal day (PN) 14 and PN21. Accordingly, the mean intensity of vesicular glutamate transporter (VGluT1) and Calbindin immunofluorescence was reduced in mild ID, severe ID, and MMZ groups. Moreover, maternal hypothyroxinemia and hypothyroidism reduced expression of Neurexin1/Cbln1/GluD2 tripartite complex. Our study supports the hypothesis that developmental hypothyroxinemia and hypothyroidism reduce PF-PC synapses, which may be attributed to the downregulation of Neurexin1/Cbln1/GluD2 tripartite complex.

[Does the recent psychosocial research consider the perspective of developmental psychopathology?].

PubMed

Glaesmer, Heide; Petermann, Franz; Schüssler, Gerhard

2009-10-01

Developmental psychopathology is studying the development of psychological disorders with a life course perspective and an interdisciplinary approach considering the interplay of biological, psychological and social factors in complex models. The bibliometric analysis examines the implementation of this concept in the recent psychosocial research in the German-speaking area. Volumes 2007 and 2008 of three German psychological journals "Zeitschrift für Psychotherapie, Psychosomatik und Medizinische Psychologie", "Zeitschrift für Psychosomatische Medizin und Psychotherapie", and "Zeitschrift für Psychiatrie, Psychologie und Psychotherapie" were screened for articles dealing with issues of developmental psychopathology. 46 articles were identified and evaluated. Several aspects of developmental psychopathology are considered in a vast number of studies, but there is a main focus on risk factors, but not on protective factors and most of the studies are based on cross-sectional designs. Most of the recent practice in psychosocial research is not beneficial for the identification of causal effects or the complex interplay of risk and protective factors in the development of psychological disorders. Thus, longitudinal studies, taking biological, psychological and social factors and their interplay into account are essential to meet the requirement of developmental psychopathology. Georg Thieme Verlag KG Stuttgart. New York.

Achieving sustainable cultivation of potatoes

USDA-ARS?s Scientific Manuscript database

Every phase of the production cycle impacts the sustainability of potato. Potato physiology determines how genetically encoded developmental attributes interact with local environmental conditions as modified through agricultural practice to produce a perishable crop. In this chapter we highlight ho...

Health Care Outcomes in the Black Community

ERIC Educational Resources Information Center

Yabura, Lloyd

1977-01-01

Notes that the forces of exploitation and racism relegate millions of human beings to a developmental cycle characterized by excessive and disproportionate infant mortality, maternal mortality, premature births, hunger and malnutrition, lead poisoning and untreated chronic disabilities. (Author)

Streptomyces exploration is triggered by fungal interactions and volatile signals

PubMed Central

Jones, Stephanie E; Ho, Louis; Rees, Christiaan A; Hill, Jane E; Nodwell, Justin R; Elliot, Marie A

2017-01-01

It has long been thought that the life cycle of Streptomyces bacteria encompasses three developmental stages: vegetative hyphae, aerial hyphae and spores. Here, we show interactions between Streptomyces and fungi trigger a previously unobserved mode of Streptomyces development. We term these Streptomyces cells ‘explorers’, for their ability to adopt a non-branching vegetative hyphal conformation and rapidly transverse solid surfaces. Fungi trigger Streptomyces exploratory growth in part by altering the composition of the growth medium, and Streptomyces explorer cells can communicate this exploratory behaviour to other physically separated streptomycetes using an airborne volatile organic compound (VOC). These results reveal that interkingdom interactions can trigger novel developmental behaviours in bacteria, here, causing Streptomyces to deviate from its classically-defined life cycle. Furthermore, this work provides evidence that VOCs can act as long-range communication signals capable of propagating microbial morphological switches. DOI: http://dx.doi.org/10.7554/eLife.21738.001 PMID:28044982

The Epigenome, Cell Cycle, and Development in Toxoplasma.

PubMed

Kim, Kami

2018-06-22

Toxoplasma gondii is a common veterinary and human pathogen that persists as latent bradyzoite forms within infected hosts. The ability of the parasite to interconvert between tachyzoite and bradyzoite is key for pathogenesis of toxoplasmosis, particularly in immunocompromised individuals. The transition between tachyzoites and bradyzoites is epigenetically regulated and coupled to the cell cycle. Recent epigenomic studies have begun to elucidate the chromatin states associated with developmental switches in T. gondii. Evidence is also emerging that AP2 transcription factors both activate and repress the bradyzoite developmental program. Further studies are needed to understand the mechanisms by which T. gondii transduces environmental signals to coordinate the epigenetic and transcriptional machinery that are responsible for tachyzoite-bradyzoite interconversion. Expected final online publication date for the Annual Review of Microbiology Volume 72 is September 8, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

III. FROM SMALL TO BIG: METHODS FOR INCORPORATING LARGE SCALE DATA INTO DEVELOPMENTAL SCIENCE.

PubMed

Davis-Kean, Pamela E; Jager, Justin

2017-06-01

For decades, developmental science has been based primarily on relatively small-scale data collections with children and families. Part of the reason for the dominance of this type of data collection is the complexity of collecting cognitive and social data on infants and small children. These small data sets are limited in both power to detect differences and the demographic diversity to generalize clearly and broadly. Thus, in this chapter we will discuss the value of using existing large-scale data sets to tests the complex questions of child development and how to develop future large-scale data sets that are both representative and can answer the important questions of developmental scientists. © 2017 The Society for Research in Child Development, Inc.

Developmental biology of Streptomyces from the perspective of 100 actinobacterial genome sequences

PubMed Central

Chandra, Govind; Chater, Keith F

2014-01-01

To illuminate the evolution and mechanisms of actinobacterial complexity, we evaluate the distribution and origins of known Streptomyces developmental genes and the developmental significance of actinobacteria-specific genes. As an aid, we developed the Actinoblast database of reciprocal blastp best hits between the Streptomyces coelicolor genome and more than 100 other actinobacterial genomes (http://streptomyces.org.uk/actinoblast/). We suggest that the emergence of morphological complexity was underpinned by special features of early actinobacteria, such as polar growth and the coupled participation of regulatory Wbl proteins and the redox-protecting thiol mycothiol in transducing a transient nitric oxide signal generated during physiologically stressful growth transitions. It seems that some cell growth and division proteins of early actinobacteria have acquired greater importance for sporulation of complex actinobacteria than for mycelial growth, in which septa are infrequent and not associated with complete cell separation. The acquisition of extracellular proteins with structural roles, a highly regulated extracellular protease cascade, and additional regulatory genes allowed early actinobacterial stationary phase processes to be redeployed in the emergence of aerial hyphae from mycelial mats and in the formation of spore chains. These extracellular proteins may have contributed to speciation. Simpler members of morphologically diverse clades have lost some developmental genes. PMID:24164321

Atypical Infant Development. Second Edition.

ERIC Educational Resources Information Center

Hanson, Marci J., Ed.

The 13 chapters of this text focus on the complex development issues and interdisciplinary service needs of infants and young children at risk and their families. The text is organized into four sections on: developmental and intervention principles, identification and assessment, developmental issues, and early intervention. Chapter titles and…

DOSIMETRY AND REPRODUCTIVE/DEVELOPMENTAL STUDY DESIGN AND INTERPRETATION FOR RISK OR SAFETY ASSESSMENT

EPA Science Inventory

Increasingly reproductive and developmental toxicity studies are utilized in assessing the potential for adverse affects in pregnant women, nursing infants, and children. These studies largely have been utilized based upon the dose to the mother due to the complexity of describin...

Complex Dynamics in Academics' Developmental Processes in Teaching

ERIC Educational Resources Information Center

Trautwein, Caroline; Nückles, Matthias; Merkt, Marianne

2015-01-01

Improving teaching in higher education is a concern for universities worldwide. This study explored academics' developmental processes in teaching using episodic interviews and teaching portfolios. Eight academics in the context of teaching development reported changes in their teaching and change triggers. Thematic analyses revealed seven areas…

Evolution of caudal fin ray development and caudal fin hypural diastema complex in spotted gar, teleosts, and other neopterygian fishes.

PubMed

Desvignes, Thomas; Carey, Andrew; Postlethwait, John H

2018-06-01

The caudal fin of actinopterygians transitioned from a heterocercal dorsoventrally asymmetrical fin to a homocercal externally symmetrical fin in teleosts through poorly understood evolutionary developmental mechanisms. We studied the caudal skeleton of major living actinopterygian lineages, including polypteriformes, acipenseriformes, Holostei (gars and bowfin), and teleosts, compared with reports of extinct neopterygians and basal teleosteans. We focused on the hypural diastema complex, which includes (1) a gap between hypurals 2 and 3, that (2) separates two plates of connective tissue at (3) the branching of caudal vasculature; these features had been considered as a shared, derived trait of teleosts, a synapomorphy. These studies revealed that gars and teleosts share all three features of the hypural diastema complex. Absence of a complex with these features from bowfin, fossil Holostei, and stem Teleostei argues in favor of repetitive, independent emergence in several neopterygian and basal Teleostei lineages, or less likely, many independent losses. We further observed that, in gars and teleosts, the earliest developing lepidotrichia align with the horizontal adult body axis, thus participating in external symmetry. These results suggest that the hypural diastema complex in teleosts and gars represents a homoplasy among neopterygians and that it emerged repeatedly by parallel evolution due to shared inherited underlying genetic and developmental programs (latent homology). Because the hypural diastema complex exists in gars with heterocercal tails, this complex is independent of homocercality. Developmental Dynamics 247:832-853, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Differentially-dimensioned furrow formation by zygotic gene expression and the MBT

PubMed Central

Xie, Yi

2018-01-01

Despite extensive work on the mechanisms that generate plasma membrane furrows, understanding how cells are able to dynamically regulate furrow dimensions is an unresolved question. Here, we present an in-depth characterization of furrow behaviors and their regulation in vivo during early Drosophila morphogenesis. We show that the deepening in furrow dimensions with successive nuclear cycles is largely due to the introduction of a new, rapid ingression phase (Ingression II). Blocking the midblastula transition (MBT) by suppressing zygotic transcription through pharmacological or genetic means causes the absence of Ingression II, and consequently reduces furrow dimensions. The analysis of compound chromosomes that produce chromosomal aneuploidies suggests that multiple loci on the X, II, and III chromosomes contribute to the production of differentially-dimensioned furrows, and we track the X-chromosomal contribution to furrow lengthening to the nullo gene product. We further show that checkpoint proteins are required for furrow lengthening; however, mitotic phases of the cell cycle are not strictly deterministic for furrow dimensions, as a decoupling of mitotic phases with periods of active ingression occurs as syncytial furrow cycles progress. Finally, we examined the turnover of maternal gene products and find that this is a minor contributor to the developmental regulation of furrow morphologies. Our results suggest that cellularization dynamics during cycle 14 are a continuation of dynamics established during the syncytial cycles and provide a more nuanced view of developmental- and MBT-driven morphogenesis. PMID:29337989

Human behavioral complexity peaks at age 25

PubMed Central

Brugger, Peter

2017-01-01

Random Item Generation tasks (RIG) are commonly used to assess high cognitive abilities such as inhibition or sustained attention. They also draw upon our approximate sense of complexity. A detrimental effect of aging on pseudo-random productions has been demonstrated for some tasks, but little is as yet known about the developmental curve of cognitive complexity over the lifespan. We investigate the complexity trajectory across the lifespan of human responses to five common RIG tasks, using a large sample (n = 3429). Our main finding is that the developmental curve of the estimated algorithmic complexity of responses is similar to what may be expected of a measure of higher cognitive abilities, with a performance peak around 25 and a decline starting around 60, suggesting that RIG tasks yield good estimates of such cognitive abilities. Our study illustrates that very short strings of, i.e., 10 items, are sufficient to have their complexity reliably estimated and to allow the documentation of an age-dependent decline in the approximate sense of complexity. PMID:28406953

The phallic castration complex and primary femininity: paired developmental lines toward female gender identity.

PubMed

Mayer, E L

1995-01-01

I suggest that two developmental lines contribute to the achievement of female gender identity. One is rooted in the phallic castration complex, and the other in primary femininity. Far from being mutually exclusive, the two comprise necessary aspects of every girl's progress toward becoming a woman. To that extent, every woman's analysis will include the analysis of compromise formations that emerge from both. In distinguishing clinical manifestations of each developmental line, I suggest that it may be useful to conceptualize primary femininity and the phallic castration complex as affect-defense configurations which incorporate two fundamentally different ideas about danger. In conflicts of primary femininity, danger is anticipated: anxiety is the signal for compromise formation, since what is actually possessed (the female genital) is valued and is therefore imagined as subject to danger. In the phallic castration complex, danger is imagined already to have occurred. Depressive affect becomes the primary motive for defense, based on a fantasy that what is valued (the male genital) has already been lost. This distinction may facilitate our efforts to specify exactly how recent revisions in theories of female development have explicit implications for practice.

Genome-wide survey of B-box proteins in potato (Solanum tuberosum)-Identification, characterization and expression patterns during diurnal cycle, etiolation and de-etiolation.

PubMed

Talar, Urszula; Kiełbowicz-Matuk, Agnieszka; Czarnecka, Jagoda; Rorat, Tadeusz

2017-01-01

Plant B-box domain proteins (BBX) mediate many light-influenced developmental processes including seedling photomorphogenesis, seed germination, shade avoidance and photoperiodic regulation of flowering. Despite the wide range of potential functions, the current knowledge regarding BBX proteins in major crop plants is scarce. In this study, we identify and characterize the StBBX gene family in potato, which is composed of 30 members, with regard to structural properties and expression profiles under diurnal cycle, etiolation and de-etiolations. Based on domain organization and phylogenetic relationships, StBBX genes have been classified into five groups. Using real-time quantitative PCR, we found that expression of most of them oscillates following a 24-h rhythm; however, large differences in expression profiles were observed between the genes regarding amplitude and position of the maximal and minimal expression levels in the day/night cycle. On the basis of the time-of-day/time-of-night, we distinguished three expression groups specifically expressed during the light and two during the dark phase. In addition, we showed that the expression of several StBBX genes is under the control of the circadian clock and that some others are specifically associated with the etiolation and de-etiolation conditions. Thus, we concluded that StBBX proteins are likely key players involved in the complex diurnal and circadian networks regulating plant development as a function of light conditions and day duration.

Mapping methyl jasmonate-mediated transcriptional reprogramming of metabolism and cell cycle progression in cultured Arabidopsis cells

PubMed Central

Pauwels, Laurens; Morreel, Kris; De Witte, Emilie; Lammertyn, Freya; Van Montagu, Marc; Boerjan, Wout; Inzé, Dirk; Goossens, Alain

2008-01-01

Jasmonates (JAs) are plant-specific signaling molecules that steer a diverse set of physiological and developmental processes. Pathogen attack and wounding inflicted by herbivores induce the biosynthesis of these hormones, triggering defense responses both locally and systemically. We report on alterations in the transcriptome of a fast-dividing cell culture of the model plant Arabidopsis thaliana after exogenous application of methyl JA (MeJA). Early MeJA response genes encoded the JA biosynthesis pathway proteins and key regulators of MeJA responses, including most JA ZIM domain proteins and MYC2, together with transcriptional regulators with potential, but yet unknown, functions in MeJA signaling. In a second transcriptional wave, MeJA reprogrammed cellular metabolism and cell cycle progression. Up-regulation of the monolignol biosynthesis gene set resulted in an increased production of monolignols and oligolignols, the building blocks of lignin. Simultaneously, MeJA repressed activation of M-phase genes, arresting the cell cycle in G2. MeJA-responsive transcription factors were screened for their involvement in early signaling events, in particular the regulation of JA biosynthesis. Parallel screens based on yeast one-hybrid and transient transactivation assays identified both positive (MYC2 and the AP2/ERF factor ORA47) and negative (the C2H2 Zn finger proteins STZ/ZAT10 and AZF2) regulators, revealing a complex control of the JA autoregulatory loop and possibly other MeJA-mediated downstream processes. PMID:18216250

IMPACTS OF BIOFILM FORMATION ON CELLULOSE FERMENTATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leschine, Susan

2009-10-31

This project addressed four major areas of investigation: i) characterization of formation of Cellulomonas uda biofilms on cellulose; ii) characterization of Clostridium phytofermentans biofilm development; colonization of cellulose and its regulation; iii) characterization of Thermobifida fusca biofilm development; colonization of cellulose and its regulation; and iii) description of the architecture of mature C. uda, C. phytofermentans, and T. fusca biofilms. This research is aimed at advancing understanding of biofilm formation and other complex processes involved in the degradation of the abundant cellulosic biomass, and the biology of the microbes involved. Information obtained from these studies is invaluable in the developmentmore » of practical applications, such as the single-step bioconversion of cellulose-containing residues to fuels and other bioproducts. Our results have clearly shown that cellulose-decomposing microbes rapidly colonize cellulose and form complex structures typical of biofilms. Furthermore, our observations suggest that, as cells multiply on nutritive surfaces during biofilms formation, dramatic cell morphological changes occur. We speculated that morphological changes, which involve a transition from rod-shaped cells to more rounded forms, might be more apparent in a filamentous microbe. In order to test this hypothesis, we included in our research a study of biofilm formation by T. fusca, a thermophilic cellulolytic actinomycete commonly found in compost. The cellulase system of T. fusca has been extensively detailed through the work of David Wilson and colleagues at Cornell, and also, genome sequence of a T. fusca strain has been determine by the DOE Joint Genome Institute. Thus, T. fusca is an excellent subject for studies of biofilm development and its potential impacts on cellulose degradation. We also completed a study of the chitinase system of C. uda. This work provided essential background information for understanding how C. uda colonizes and degrades insoluble substrates. Major accomplishments of the project include: • Development of media containing dialysis tubing (described by the manufacturer as “regenerated cellulose”) as sole carbon and energy source and a nutritive surface for the growth of cellulolytic bacteria, and development of various microscopic methods to image biofilms on dialysis tubing. • Demonstration that cultures of C. phytofermentans, an obligate anaerobe, C. uda, a facultative aerobe, and T. fusca, a filamentous aerobe, formed microbial communities on the surface of dialysis tubing, which possessed architectural features and functional characteristics typical of biofilms. • Demonstration that biofilm formation on the nutritive surface, cellulose, involves a complex developmental processes, including colonization of dialysis tubing, formation of cell clusters attached to the nutritive surface, cell morphological changes, formation of complex structures embedded in extracellular polymeric matrices, and dispersal of biofilm communities as the nutritive surface is degraded. • Determination of surface specificity and regulatory aspects of biofilm formation by C. phytofermentans, C. uda, and T. fusca. • Demonstration that biofilm formation by T. fusca forms an integral part of the life cycle of this filamentous cellulolytic bacterium, including studies on the role of mycelial pellet formation in the T. fusca life cycle and a comparison of mycelial pellets to surface-attached T. fusca biofilms. • Characterization of T. fusca biofilm EPS, including demonstration of a functional role for EPS constituents. • Correlation of T. fusca developmental life cycle and cellulase gene expression.« less

A Biosocial Developmental Model of Borderline Personality: Elaborating and Extending Linehan's Theory

ERIC Educational Resources Information Center

Crowell, Sheila E.; Beauchaine, Theodore P.; Linehan, Marsha M.

2009-01-01

Over the past several decades, research has focused increasingly on developmental precursors to psychological disorders that were previously assumed to emerge only in adulthood. This change in focus follows from the recognition that complex transactions between biological vulnerabilities and psychosocial risk factors shape emotional and behavioral…

Working Memory and Mathematics: A Review of Developmental, Individual Difference, and Cognitive Approaches

ERIC Educational Resources Information Center

Raghubar, Kimberly P.; Barnes, Marcia A.; Hecht, Steven A.

2010-01-01

Working memory refers to a mental workspace, involved in controlling, regulating, and actively maintaining relevant information to accomplish complex cognitive tasks (e.g. mathematical processing). Despite the potential relevance of a relation between working memory and math for understanding developmental and individual differences in…

A Comparison of Forgiveness and Pro-Social Development.

ERIC Educational Resources Information Center

Scobie, G. E. W.; Scobie, E. D.

2000-01-01

Considers how forgiveness is learned and what developmental features it has in common with other prosocial activities. Maintains that viewing forgiveness within a moral developmental framework does not consider its complex nature nor address related issues such as damage severity, restoring relationships, empathy, or altruism. Explores these areas…

Differential Susceptibility to the Environment: Are Developmental Models Compatible with the Evidence from Twin Studies?

ERIC Educational Resources Information Center

Del Giudice, Marco

2016-01-01

According to models of differential susceptibility, the same neurobiological and temperamental traits that determine increased sensitivity to stress and adversity also confer enhanced responsivity to the positive aspects of the environment. Differential susceptibility models have expanded to include complex developmental processes in which genetic…

Multiple Sensory-Motor Pathways Lead to Coordinated Visual Attention

ERIC Educational Resources Information Center

Yu, Chen; Smith, Linda B.

2017-01-01

Joint attention has been extensively studied in the developmental literature because of overwhelming evidence that the ability to socially coordinate visual attention to an object is essential to healthy developmental outcomes, including language learning. The goal of this study was to understand the complex system of sensory-motor behaviors that…

Learning through Seeing and Doing: Visual Supports for Children with Autism

ERIC Educational Resources Information Center

Rao, Shaila M.; Gagie, Brenda

2006-01-01

Autism is a life-long, complex developmental disorder that causes impairment in the way individuals process information. Autism belongs to heterogeneous categories of developmental disabilities where neurological disorders lead to deficits in a child's ability to communicate, understand language, play, develop social skills, and relate to others.…

Developmental Perspectives on Reflective Practices of Elementary Science Education Students

ERIC Educational Resources Information Center

Olson, Joanne K.; Finson, Kevin D.

2009-01-01

Instructors of elementary science methods classes have long lamented the significant difficulties their students exhibit when trying to understand the many complexities of teaching science. As noted by some researchers and practicing teachers, preservice teachers often fail to developmentally function at desired levels with respect to…

Diagnosing Autism in Individuals with Known Genetic Syndromes: Clinical Considerations and Implications for Intervention

PubMed Central

Hepburn, Susan L.; Moody, Eric J.

2015-01-01

Assessing symptoms of autism in persons with known genetic syndromes associated with intellectual and/or developmental disability is a complex clinical endeavor. We suggest that a developmental approach to evaluation is essential to reliably teasing apart global impairments from autism-specific symptomology. In this chapter, we discuss our assumptions about autism spectrum disorders, the process of conducting a family-focused, comprehensive evaluation with behaviorally complex children and some implications for intervention in persons with co-occurring autism and known genetic syndromes. PMID:26269783

Conservation in the involvement of heterochronic genes and hormones during developmental transitions.

PubMed

Faunes, Fernando; Larraín, Juan

2016-08-01

Developmental transitions include molting in some invertebrates and the metamorphosis of insects and amphibians. While the study of Caenorhabditis elegans larval transitions was crucial to determine the genetic control of these transitions, Drosophila melanogaster and Xenopus laevis have been classic models to study the role of hormones in metamorphosis. Here we review how heterochronic genes (lin-4, let-7, lin-28, lin-41), hormones (dafachronic acid, ecdysone, thyroid hormone) and the environment regulate developmental transitions. Recent evidence suggests that some heterochronic genes also regulate transitions in higher organisms that they are controlled by hormones involved in metamorphosis. We also discuss evidence demonstrating that heterochronic genes and hormones regulate the proliferation and differentiation of embryonic and neural stem cells. We propose the hypothesis that developmental transitions are regulated by an evolutionary conserved mechanism in which heterochronic genes and hormones interact to control stem/progenitor cells proliferation, cell cycle exit, quiescence and differentiation and determine the proper timing of developmental transitions. Finally, we discuss the relevance of these studies to understand post-embryonic development, puberty and regeneration in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

Mathematical modelling in developmental biology.

PubMed

Vasieva, Olga; Rasolonjanahary, Manan'Iarivo; Vasiev, Bakhtier

2013-06-01

In recent decades, molecular and cellular biology has benefited from numerous fascinating developments in experimental technique, generating an overwhelming amount of data on various biological objects and processes. This, in turn, has led biologists to look for appropriate tools to facilitate systematic analysis of data. Thus, the need for mathematical techniques, which can be used to aid the classification and understanding of this ever-growing body of experimental data, is more profound now than ever before. Mathematical modelling is becoming increasingly integrated into biological studies in general and into developmental biology particularly. This review outlines some achievements of mathematics as applied to developmental biology and demonstrates the mathematical formulation of basic principles driving morphogenesis. We begin by describing a mathematical formalism used to analyse the formation and scaling of morphogen gradients. Then we address a problem of interplay between the dynamics of morphogen gradients and movement of cells, referring to mathematical models of gastrulation in the chick embryo. In the last section, we give an overview of various mathematical models used in the study of the developmental cycle of Dictyostelium discoideum, which is probably the best example of successful mathematical modelling in developmental biology.

Future Directions in Sleep and Developmental Psychopathology.

PubMed

Meltzer, Lisa J

2017-01-01

It is critical for psychologists to gain a better understanding about the intersection between sleep and developmental psychopathology. However, while many strive to answer the question of whether sleep causes developmental psychopathology, or vice versa, ultimately the relationship between sleep and developmental psychopathology is complex and dynamic. This article considers future directions in the field of clinical child and adolescent psychology that go beyond this mechanistic question, highlighting areas important to address for clinicians and researchers who strive to better understand how best to serve children and adolescents with developmental psychopathology. Questions are presented about what is normal in terms of sleep across development, the role of individual variability in terms of sleep needs and vulnerability to sleep loss, and how sleep may serve as a risk or resilience factor for developmental psychopathology, concluding with considerations for interventions.

The role of the PI3K-Akt signaling pathway in the developmental competence of bovine oocytes.

PubMed

Andrade, Gabriella Mamede; da Silveira, Juliano Coelho; Perrini, Claudia; Del Collado, Maite; Gebremedhn, Samuel; Tesfaye, Dawit; Meirelles, Flávio Vieira; Perecin, Felipe

2017-01-01

The ovarian follicle encloses oocytes in a microenvironment throughout their growth and acquisition of competence. Evidence suggests a dynamic interplay among follicular cells and oocytes, since they are constantly exchanging "messages". We dissected bovine ovarian follicles and recovered follicular cells (FCs-granulosa and cumulus cells) and cumulus-oocyte complexes (COCs) to investigate whether the PI3K-Akt signaling pathway impacted oocyte quality. Following follicle rupture, COCs were individually selected for in vitro cultures to track the follicular cells based on oocyte competence to reach the blastocyst stage after parthenogenetic activation. Levels of PI3K-Akt signaling pathway components in FCs correlated with oocyte competence. This pathway is upregulated in FCs from follicles with high-quality oocytes that are able to reach the blastocyst stage, as indicated by decreased levels of PTEN and increased levels of the PTEN regulators bta-miR-494 and bta-miR-20a. Using PI3K-Akt responsive genes, we showed decreased FOXO3a levels and BAX levels in lower quality groups, indicating changes in cell cycle progression, oxidative response and apoptosis. Based on these results, the measurement of levels of PI3K-Akt pathway components in FCs from ovarian follicles carrying oocytes with distinct developmental competences is a useful tool to identify putative molecular pathways involved in the acquisition of oocyte competence.

Developmental transcriptome profiling of bovine muscle tissue reveals an abundant GosB that regulates myoblast proliferation and apoptosis

PubMed Central

Yang, Jiameng; Dong, Dong; Huang, Yongzhen; Lan, Xianyong; Plath, Martin; Lei, Chuzhao; Qi, Xinglei; Bai, Yueyu; Chen, Hong

2017-01-01

The formation of bovine skeletal muscle involves complex developmental and physiological processes that play a vital role in determining the quality of beef; however, the regulatory mechanisms underlying differences in meat quality are largely unknown. We conducted transcriptome analysis of bovine muscle tissues to compare gene expression profiles between embryonic and adult stages. Total RNAs from skeletal muscle of Qinchuan cattle at fetal and adult stages were used to construct libraries for Illumina next-generation sequencing using the Ribo-Zero RNA sequencing (RNA-Seq) method. We found a total of 19,695 genes to be expressed in fetal and adult stages, whereby 3,299 were expressed only in fetal, and 433 only in adult tissues. We characterized the role of a candidate gene (GosB), which was highly (but differentially) expressed in embryonic and adult skeletal muscle tissue. GosB increased the number of myoblasts in the S-phase of the cell cycle, and decreased the proportion of cells in the G0/G1 phase. GosB promoted the proliferation of myoblasts and protected them from apoptosis via regulating Bcl-2 expression and controlling the intracellular calcium concentration. Modulation of GosB expression in muscle tissue may emerge as a potential target in breeding strategies attempting to alter myoblast numbers in cattle. PMID:28404879

FT Duplication Coordinates Reproductive and Vegetative Growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Chuan-Yu; Adams, Joshua P.; Kim, Hyejin

2011-01-01

Annual plants grow vegetatively at early developmental stages and then transition to the reproductive stage, followed by senescence in the same year. In contrast, after successive years of vegetative growth at early ages, woody perennial shoot meristems begin repeated transitions between vegetative and reproductive growth at sexual maturity. However, it is unknown how these repeated transitions occur without a developmental conflict between vegetative and reproductive growth. We report that functionally diverged paralogs FLOWERING LOCUS T1 (FT1) and FLOWERING LOCUS T2 (FT2), products of whole-genome duplication and homologs of Arabidopsis thaliana gene FLOWERING LOCUS T (FT), coordinate the repeated cycles ofmore » vegetative and reproductive growth in woody perennial poplar (Populus spp.). Our manipulative physiological and genetic experiments coupled with field studies, expression profiling, and network analysis reveal that reproductive onset is determined by FT1 in response to winter temperatures, whereas vegetative growth and inhibition of bud set are promoted by FT2 in response to warm temperatures and long days in the growing season. The basis for functional differentiation between FT1 and FT2 appears to be expression pattern shifts, changes in proteins, and divergence in gene regulatory networks. Thus, temporal separation of reproductive onset and vegetative growth into different seasons via FT1 and FT2 provides seasonality and demonstrates the evolution of a complex perennial adaptive trait after genome duplication.« less

Evidence that divergent selection shapes a developmental cline in a forest tree species complex.

PubMed

Costa E Silva, João; Harrison, Peter A; Wiltshire, Robert; Potts, Brad M

2018-05-19

Evolutionary change in developmental trajectories (heterochrony) is a major mechanism of adaptation in plants and animals. However, there are few detailed studies of the variation in the timing of developmental events among wild populations. We here aimed to identify the climatic drivers and measure selection shaping a genetic-based developmental cline among populations of an endemic tree species complex on the island of Tasmania. Seed lots from 38 native provenances encompassing the clinal transition from the heteroblastic Eucalyptus tenuiramis to the homoblastic Eucalyptus risdonii were grown in a common-garden field trial in southern Tasmania for 20 years. We used 27 climatic variables to model the provenance variation in vegetative juvenility as assessed at age 5 years. A phenotypic selection analysis was used to measure the fitness consequences of variation in vegetative juvenility based on its impact on the survival and reproductive capacity of survivors at age 20 years. Significant provenance divergence in vegetative juvenility was shown to be associated with home-site aridity, with the retention of juvenile foliage increasing with increasing aridity. Our results indicated that climate change may lead to different directions of selection across the geographic range of the complex, and in our mesic field site demonstrated that total directional selection within phenotypically variable provenances was in favour of reduced vegetative juvenility. We provide evidence that heteroblasty is adaptive and argue that, in assessing the impacts of rapid global change, developmental plasticity and heterochrony are underappreciated processes which can contribute to populations of long-lived organisms, such as trees, persisting and ultimately adapting to environmental change.

The Caenorhabditis elegans LET-418/Mi2 plays a conserved role in lifespan regulation.

PubMed

De Vaux, Véronique; Pfefferli, Catherine; Passannante, Myriam; Belhaj, Khaoula; von Essen, Alina; Sprecher, Simon G; Müller, Fritz; Wicky, Chantal

2013-12-01

The evolutionarily conserved nucleosome-remodeling protein Mi2 is involved in transcriptional repression during development in various model systems, plays a role in embryonic patterning and germ line development, and participates in DNA repair and cell cycle progression. It is the catalytic subunit of the nucleosome remodeling and histone deacetylase (NuRD) complex, a key determinant of differentiation in mammalian embryonic stem cells. In addition, the Drosophila and C. elegans Mi2 homologs participate in another complex, the MEC complex, which also plays an important developmental role in these organisms. Here we show a new and unexpected feature of the C. elegans Mi2 homolog, LET-418/Mi2. Lack of LET-418/Mi2 results in longevity and enhanced stress resistance, a feature that we found to be conserved in Drosophila and in Arabidopsis. The fact that depletion of other components of the NuRD and the MEC complexes did not result in longevity suggests that LET-418 may regulate lifespan in a different molecular context. Genetic interaction studies suggest that let-418 could act in the germ-cell-loss pathway, downstream of kri-1 and tcer-1. On the basis of our data and on previous findings showing a role for let-418 during development, we propose that LET-418/Mi2 could be part of a system that drives development and reproduction with concomitant life-reducing effects later in life. © 2013 the Anatomical Society and John Wiley & Sons Ltd.

Changing expressions: a hypothesis for the origin of the vascular plant life cycle.

PubMed

Kenrick, Paul

2018-02-05

Plant life cycles underwent fundamental changes during the initial colonization of the land in the Early Palaeozoic, shaping the direction of evolution. Fossils reveal unanticipated diversity, including new variants of meiotic cell division and leafless gametophytes with mycorrhizal-like symbioses, rhizoids, vascular tissues and stomata. Exceptional fossils from the 407-Ma Rhynie chert (Scotland) play a key role in unlocking this diversity. These fossils are reviewed against progress in our understanding of the plant tree of life and recent advances in developmental genetics. Combining data from different sources sheds light on a switch in life cycle that gave rise to the vascular plants. One crucial step was the establishment of a free-living sporophyte from one that was an obligate matrotroph borne on the gametophyte. It is proposed that this difficult evolutionary transition was achieved through expansion of gene expression primarily from the gametophyte to the sporophyte, establishing a now extinct life cycle variant that was more isomorphic than heteromorphic. These changes also linked for the first time in one developmental system rhizoids, vascular tissues and stomata, putting in place the critical components that regulate transpiration and forming a physiological platform of primary importance to the diversification of vascular plants.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Author(s).

The Conceptual Complexity of Vocabulary in Elementary-Grades Core Science Program Textbooks

ERIC Educational Resources Information Center

Fitzgerald, W. Jill; Elmore, Jeff; Kung, Melody; Stenner, A. Jackson

2017-01-01

The researchers explored the conceptual complexity of vocabulary in contemporary elementary-grades core science program textbooks to address two research questions: (1) Can a progression of concepts' complexity level be described across grades? (2) Was there gradual developmental growth of the most complex concepts' networks of associated concepts…

Identifying candidate genes affecting developmental time in Drosophila melanogaster: pervasive pleiotropy and gene-by-environment interaction

PubMed Central

Mensch, Julián; Lavagnino, Nicolás; Carreira, Valeria Paula; Massaldi, Ana; Hasson, Esteban; Fanara, Juan José

2008-01-01

Background Understanding the genetic architecture of ecologically relevant adaptive traits requires the contribution of developmental and evolutionary biology. The time to reach the age of reproduction is a complex life history trait commonly known as developmental time. In particular, in holometabolous insects that occupy ephemeral habitats, like fruit flies, the impact of developmental time on fitness is further exaggerated. The present work is one of the first systematic studies of the genetic basis of developmental time, in which we also evaluate the impact of environmental variation on the expression of the trait. Results We analyzed 179 co-isogenic single P[GT1]-element insertion lines of Drosophila melanogaster to identify novel genes affecting developmental time in flies reared at 25°C. Sixty percent of the lines showed a heterochronic phenotype, suggesting that a large number of genes affect this trait. Mutant lines for the genes Merlin and Karl showed the most extreme phenotypes exhibiting a developmental time reduction and increase, respectively, of over 2 days and 4 days relative to the control (a co-isogenic P-element insertion free line). In addition, a subset of 42 lines selected at random from the initial set of 179 lines was screened at 17°C. Interestingly, the gene-by-environment interaction accounted for 52% of total phenotypic variance. Plastic reaction norms were found for a large number of developmental time candidate genes. Conclusion We identified components of several integrated time-dependent pathways affecting egg-to-adult developmental time in Drosophila. At the same time, we also show that many heterochronic phenotypes may arise from changes in genes involved in several developmental mechanisms that do not explicitly control the timing of specific events. We also demonstrate that many developmental time genes have pleiotropic effects on several adult traits and that the action of most of them is sensitive to temperature during development. Taken together, our results stress the need to take into account the effect of environmental variation and the dynamics of gene interactions on the genetic architecture of this complex life-history trait. PMID:18687152

Structure and function of the homeotic gene complex (HOM-C) in the beetle, Tribolium castaneum

NASA Technical Reports Server (NTRS)

Beeman, R. W.; Stuart, J. J.; Brown, S. J.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

1993-01-01

The powerful combination of genetic, developmental and molecular approaches possible with the fruit fly, Drosophila melanogaster, has led to a profound understanding of the genetic control of early developmental events. However, Drosophila is a highly specialized long germ insect, and the mechanisms controlling its early development may not be typical of insects or Arthropods in general. The beetle, Tribolium castaneum, offers a similar opportunity to integrate high resolution genetic analysis with the developmental/molecular approaches currently used in other organisms. Early results document significant differences between insect orders in the functions of genes responsible for establishing developmental commitments.

Structure and function of the homeotic gene complex (HOM-C) in the beetle, Tribolium castaneum.

PubMed

Beeman, R W; Stuart, J J; Brown, S J; Denell, R E

1993-07-01

The powerful combination of genetic, developmental and molecular approaches possible with the fruit fly, Drosophila melanogaster, has led to a profound understanding of the genetic control of early developmental events. However, Drosophila is a highly specialized long germ insect, and the mechanisms controlling its early development may not be typical of insects or Arthropods in general. The beetle, Tribolium castaneum, offers a similar opportunity to integrate high resolution genetic analysis with the developmental/molecular approaches currently used in other organisms. Early results document significant differences between insect orders in the functions of genes responsible for establishing developmental commitments.

A review of Eimeria infections in horses and other equids

USDA-ARS?s Scientific Manuscript database

There is considerable confusion concerning validity of Eimeria species in equids, and endogenous developmental stages and pathogenicity of equid Eimeria. This paper summarizes worldwide information on history, structure, life cycle, pathogenicity, prevalence, epidemiology, and diagnosis of Eimeria i...

Genomic divergence and lack of introgressive hybridization between two 13-year periodical cicadas support life cycle switching in the face of climate change.

PubMed

Koyama, Takuya; Ito, Hiromu; Fujisawa, Tomochika; Ikeda, Hiroshi; Kakishima, Satoshi; Cooley, John R; Simon, Chris; Yoshimura, Jin; Sota, Teiji

2016-11-01

Life history evolution spurred by post-Pleistocene climatic change is hypothesized to be responsible for the present diversity in periodical cicadas (Magicicada), but the mechanism of life cycle change has been controversial. To understand the divergence process of 13-year and 17-year cicada life cycles, we studied genetic relationships between two synchronously emerging, parapatric 13-year periodical cicada species in the Decim group, Magicicada tredecim and M. neotredecim. The latter was hypothesized to be of hybrid origin or to have switched from a 17-year cycle via developmental plasticity. Phylogenetic analysis using restriction-site-associated DNA sequences for all Decim species and broods revealed that the 13-year M. tredecim lineage is genomically distinct from 17-year Magicicada septendecim but that 13-year M. neotredecim is not. We detected no significant introgression between M. tredecim and M. neotredecim/M. septendecim thus refuting the hypothesis that M. neotredecim are products of hybridization between M. tredecim and M. septendecim. Further, we found that introgressive hybridization is very rare or absent in the contact zone between the two 13-year species evidenced by segregation patterns in single nucleotide polymorphisms, mitochondrial lineage identity and head width and abdominal sternite colour phenotypes. Our study demonstrates that the two 13-year Decim species are of independent origin and nearly completely reproductively isolated. Combining our data with increasing observations of occasional life cycle change in part of a cohort (e.g. 4-year acceleration of emergence in 17-year species), we suggest a pivotal role for developmental plasticity in Magicicada life cycle evolution. © 2016 John Wiley & Sons Ltd.

Reconsideration of Plant Morphological Traits: From a Structure-Based Perspective to a Function-Based Evolutionary Perspective

PubMed Central

Bai, Shu-Nong

2017-01-01

This opinion article proposes a novel alignment of traits in plant morphogenesis from a function-based evolutionary perspective. As a member species of the ecosystem on Earth, we human beings view our neighbor organisms from our own sensing system. We tend to distinguish forms and structures (i.e., “morphological traits”) mainly through vision. Traditionally, a plant was considered to be consisted of three parts, i.e., the shoot, the leaves, and the root. Based on such a “structure-based perspective,” evolutionary analyses or comparisons across species were made on particular parts or their derived structures. So far no conceptual framework has been established to incorporate the morphological traits of all three land plant phyta, i.e., bryophyta, pteridophyta and spermatophyta, for evolutionary developmental analysis. Using the tenets of the recently proposed concept of sexual reproduction cycle, the major morphological traits of land plants can be aligned into five categories from a function-based evolutionary perspective. From this perspective, and the resulting alignment, a new conceptual framework emerges, called “Plant Morphogenesis 123.” This framework views a plant as a colony of integrated plant developmental units that are each produced via one life cycle. This view provided an alternative perspective for evolutionary developmental investigation in plants. PMID:28360919

Functionality of resistance gene Hero, which controls plant root-infecting potato cyst nematodes, in leaves of tomato.

PubMed

Poch, H L Cabrera; López, R H Manzanilla; Kanyuka, K

2006-07-01

The expression of host genomes is modified locally by root endoparasitic nematode secretions to induce the development of complex cellular structures referred as feeding sites. In compatible interactions, the feeding sites provide the environment and nutrients for the completion of the nematode's life cycle, whereas in an incompatible (resistant) interaction, the host immune system triggers a plant cell death programme, often in the form of a hypersensitive reaction, which restricts nematode reproduction. These processes have been studied in great detail in organ tissues normally infected by these nematodes: the roots. Here we show that host leaves can support a similar set of programmed developmental events in the potato cyst nematode Globodera rostochiensis life cycle that are typical of the root-invading nematodes. We also show that a gene-for-gene type specific disease resistance that is effective against potato cyst nematodes (PCN) in roots also operates in leaves: the expression of the resistance (R) gene Hero and members of its gene family in leaves correlates with the elicitation of a hypersensitive response only during the incompatible interaction. These findings, and the ability to isolate RNA from relevant parasitic stages of the nematode, may have significant implications for the identification of nematode factors involved in incompatible interactions.

Systematic developmental neurotoxicity assessment of a representative PAH Superfund mixture using zebrafish

DOE PAGES

Geier, Mitra C.; James Minick, D.; Truong, Lisa; ...

2018-04-01

Superfund sites often consist of complex mixtures of polycyclic aromatic hydrocarbons (PAHs). It is widely recognized that PAHs pose risks to human and environmental health, but the risks posed by exposure to PAH mixtures are unclear. Here, we constructed an environmentally relevant PAH mixture with the top 10 most prevalent PAHs (SM10) from a Superfund site derived from environmental passive sampling data. Using the zebrafish model, we measured body burden at 48 hours post fertilization (hpf) and evaluated the developmental and neurotoxicity of SM10 and the 10 individual constituents at 24 hours post fertilization (hpf) and 5 days post fertilizationmore » (dpf). Zebrafish embryos were exposed from 6 to 120 hpf to (1) the SM10 mixture, (2) a variety of individual PAHs: pyrene, fluoranthene, retene, benzo[a]anthracene, chrysene, naphthalene, acenaphthene, phenanthrene, fluorene, and 2-methylnaphthalene. We demonstrated that SM10 and only 3 of the individual PAHs were developmentally toxic. Subsequently, we constructed and exposed developing zebrafish to two sub-mixtures: SM3 (comprised of 3 of the developmentally toxicity PAHs) and SM7 (7 non-developmentally toxic PAHs). We found that the SM3 toxicity profile was similar to SM10, and SM7 unexpectedly elicited developmental toxicity unlike that seen with its individual components. The results demonstrated that the overall developmental toxicity in the mixtures could be explained using the general concentration addition model. To determine if exposures activated the AHR pathway, spatial expression of CYP1A was evaluated in the 10 individual PAHs and the 3 mixtures at 5 dpf. Results showed activation of AHR in the liver and vasculature for the mixtures and some individual PAHs. Embryos exposed to SM10 during development and raised in chemical-free water into adulthood exhibited decreased learning and responses to startle stimulus indicating that developmental SM10 exposures affect neurobehavior. Collectively, these results exemplify the utility of zebrafish to investigate the developmental and neurotoxicity of complex mixtures.« less

Systematic developmental neurotoxicity assessment of a representative PAH Superfund mixture using zebrafish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geier, Mitra C.; James Minick, D.; Truong, Lisa

Superfund sites often consist of complex mixtures of polycyclic aromatic hydrocarbons (PAHs). It is widely recognized that PAHs pose risks to human and environmental health, but the risks posed by exposure to PAH mixtures are unclear. Here, we constructed an environmentally relevant PAH mixture with the top 10 most prevalent PAHs (SM10) from a Superfund site derived from environmental passive sampling data. Using the zebrafish model, we measured body burden at 48 hours post fertilization (hpf) and evaluated the developmental and neurotoxicity of SM10 and the 10 individual constituents at 24 hours post fertilization (hpf) and 5 days post fertilizationmore » (dpf). Zebrafish embryos were exposed from 6 to 120 hpf to (1) the SM10 mixture, (2) a variety of individual PAHs: pyrene, fluoranthene, retene, benzo[a]anthracene, chrysene, naphthalene, acenaphthene, phenanthrene, fluorene, and 2-methylnaphthalene. We demonstrated that SM10 and only 3 of the individual PAHs were developmentally toxic. Subsequently, we constructed and exposed developing zebrafish to two sub-mixtures: SM3 (comprised of 3 of the developmentally toxicity PAHs) and SM7 (7 non-developmentally toxic PAHs). We found that the SM3 toxicity profile was similar to SM10, and SM7 unexpectedly elicited developmental toxicity unlike that seen with its individual components. The results demonstrated that the overall developmental toxicity in the mixtures could be explained using the general concentration addition model. To determine if exposures activated the AHR pathway, spatial expression of CYP1A was evaluated in the 10 individual PAHs and the 3 mixtures at 5 dpf. Results showed activation of AHR in the liver and vasculature for the mixtures and some individual PAHs. Embryos exposed to SM10 during development and raised in chemical-free water into adulthood exhibited decreased learning and responses to startle stimulus indicating that developmental SM10 exposures affect neurobehavior. Collectively, these results exemplify the utility of zebrafish to investigate the developmental and neurotoxicity of complex mixtures.« less

Rate and Timing Precision of Motor Coordination in Developmental Dyslexia.

ERIC Educational Resources Information Center

Wolff, Peter H.; And Others

1990-01-01

Adolescents and young adults with developmental dyslexia and matched normal and disabled controls were asked to tap in time to a metronome at three rates by moving the index fingers of both hands in unison, in rhythmical alternation, or in more complex bimanual patterns. Dyslexic subjects showed significant deficits on asynchronous, but not…

Teaching, Learning and Leading in Today's Complex World: Reaching New Heights with a Developmental Approach

ERIC Educational Resources Information Center

Drago-Severson, Eleanor

2016-01-01

"What is happening in education today?" and "What is most needed for the future of teaching, learning and leading?" This article presents a developmental approach to learning, leadership and advancing professional learning--one that takes into account adults' diverse meaning making processes--that can help educators build the…

Transformation through Health Teaching for Adults with Intellectual and Developmental Disabilities: A Qualitative Study

ERIC Educational Resources Information Center

Focht-New, Ginny

2012-01-01

Adults with intellectual and developmental disabilities have medical conditions similar to those among the general population but with more complex presentation, a extended life expectancy, and increased risk of morbidity and mortality. These adults' health education has been inadequate. In this qualitative study, the author describes the…

Developmental Disorders of Language and Literacy: Special Issue

ERIC Educational Resources Information Center

Marshall, Chloe R.; Messaoud-Galusi, Souhila

2010-01-01

Language and literacy are cognitive skills of exceptional complexity. It is therefore not surprising that they are at risk of impairment either during development or as a result of damage (e.g. stroke) later in life. Impaired language and literacy can arise from a general learning impairment. However, two developmental disorders, specific language…

A Developmental Perspective on the Virginia Student Threat Assessment Guidelines

ERIC Educational Resources Information Center

Cornell, Dewey G.

2011-01-01

The Virginia Student Threat Assessment Guidelines were developed to help multidisciplinary school-based teams use a decision tree to evaluate student threats and take appropriate preventive action. A main goal of this approach is to allow school-based teams to recognize and respond to the developmental complexities of children and adolescents…

Using Developmental Evaluation as a Design Thinking Tool for Curriculum Innovation in Professional Higher Education

ERIC Educational Resources Information Center

Leonard, Simon N.; Fitzgerald, Robert N.; Riordan, Geoffrey

2016-01-01

This paper argues for the use of "developmental" evaluation as a design-based research tool for sustainable curriculum innovation in professional higher education. Professional education is multi-faceted and complex with diverse views from researchers, professional practitioners, employers and the world of politics leaving little…

Collaborative Developmental Action Inquiry: An Opportunity for Transformative Learning to Occur?

ERIC Educational Resources Information Center

Nicolaides, Aliki; Dzubinski, Leanne

2016-01-01

Life in the 21st century is increasingly complex, paradoxical, and ambiguous, bringing into question the ways that graduate adult education programs function. In this article, we describe an action research study involving the method of collaborative developmental action inquiry conducted with key stakeholders of a program in adult education at a…

Choreographing Learning in Developmental Psychology Utilising Multi-Generational Genograms and Reflective Journal Writing

ERIC Educational Resources Information Center

van Schalkwyk, Gertina J.

2007-01-01

Teaching a complex topic, such as lifespan developmental psychology, challenges most lecturers to find ways to produce and develop adequately students' ability to integrate theoretical knowledge and an understanding of psychosocial issues in everyday life. In this paper, I will explain the possibilities of tools from practice in creating and…

Characterization of a complex chromosomal rearrangement using chromosome, FISH, and microarray assays in a girl with multiple congenital abnormalities and developmental delay.

PubMed

Hemmat, Morteza; Yang, Xiaojing; Chan, Patricia; McGough, Robert A; Ross, Leslie; Mahon, Loretta W; Anguiano, Arturo L; Boris, Wang T; Elnaggar, Mohamed M; Wang, Jia-Chi J; Strom, Charles M; Boyar, Fatih Z

2014-01-01

Complex chromosomal rearrangements (CCRs) are balanced or unbalanced structural rearrangements involving three or more cytogenetic breakpoints on two or more chromosomal pairs. The phenotypic anomalies in such cases are attributed to gene disruption, superimposed cryptic imbalances in the genome, and/or position effects. We report a 14-year-old girl who presented with multiple congenital anomalies and developmental delay. Chromosome and FISH analysis indicated a highly complex chromosomal rearrangement involving three chromosomes (3, 7 and 12), seven breakpoints as a result of one inversion, two insertions, and two translocations forming three derivative chromosomes. Additionally, chromosomal microarray study (CMA) revealed two submicroscopic deletions at 3p12.3 (467 kb) and 12q13.12 (442 kb). We postulate that microdeletion within the ROBO1 gene at 3p12.3 may have played a role in the patient's developmental delay, since it has potential activity-dependent role in neurons. Additionally, factors other than genomic deletions such as loss of function or position effects may also contribute to the abnormal phenotype in our patient.

Temporal and spatial complexity of maternal thermoregulation in tropical pythons.

PubMed

Stahlschmidt, Zachary Ross; Shine, Richard; Denardo, Dale F

2012-01-01

Parental care is a widespread adaptation that evolved independently in a broad range of taxa. Although the dynamics by which two parents meet the developmental needs of offspring are well studied in birds, we lack understanding about the temporal and spatial complexity of parental care in taxa exhibiting female-only care, the predominant mode of parental care. Thus, we examined the behavioral and physiological mechanisms by which female water pythons Liasis fuscus meet a widespread developmental need (thermoregulation) in a natural setting. Although female L. fuscus were not facultatively thermogenic, they did use behaviors on multiple spatial scales (e.g., shifts in egg-brooding postures and surface activity patterns) to balance the thermal needs of their offspring throughout reproduction (gravidity and egg brooding). Maternal behaviors in L. fuscus varied by stage within reproduction and were mediated by interindividual variation in body size and fecundity. Female pythons with relatively larger clutch sizes were cooler during egg brooding, suggesting a trade-off between reproductive quantity (size of clutch) and quality (developmental temperature). In nature, caregiving parents of all taxa must navigate both extrinsic factors (temporal and spatial complexity) and intrinsic factors (body size and fecundity) to meet the needs of their offspring. Our study used a comprehensive approach that can be used as a general template for future research examining the dynamics by which parents meet other developmental needs (e.g., predation risk or energy balance).

Developmental programming of the metabolic syndrome - critical windows for intervention

PubMed Central

Vickers, Mark H

2011-01-01

Metabolic disease results from a complex interaction of many factors, including genetic, physiological, behavioral and environmental influences. The recent rate at which these diseases have increased suggests that environmental and behavioral influences, rather than genetic causes, are fuelling the present epidemic. In this context, the developmental origins of health and disease hypothesis has highlighted the link between the periconceptual, fetal and early infant phases of life and the subsequent development of adult obesity and the metabolic syndrome. Although the mechanisms are yet to be fully elucidated, this programming was generally considered an irreversible change in developmental trajectory. Recent work in animal models suggests that developmental programming of metabolic disorders is potentially reversible by nutritional or targeted therapeutic interventions during the period of developmental plasticity. This review will discuss critical windows of developmental plasticity and possible avenues to ameliorate the development of postnatal metabolic disorders following an adverse early life environment. PMID:21954418

The MADS-box XAANTAL1 increases proliferation at the Arabidopsis root stem-cell niche and participates in transition to differentiation by regulating cell-cycle components

PubMed Central

García-Cruz, Karla V.; García-Ponce, Berenice; Garay-Arroyo, Adriana; Sanchez, María De La Paz; Ugartechea-Chirino, Yamel; Desvoyes, Bénédicte; Pacheco-Escobedo, Mario A.; Tapia-López, Rosalinda; Ransom-Rodríguez, Ivan; Gutierrez, Crisanto; Alvarez-Buylla, Elena R.

2016-01-01

Background Morphogenesis depends on the concerted modulation of cell proliferation and differentiation. Such modulation is dynamically adjusted in response to various external and internal signals via complex transcriptional regulatory networks that mediate between such signals and regulation of cell-cycle and cellular responses (proliferation, growth, differentiation). In plants, which are sessile, the proliferation/differentiation balance is plastically adjusted during their life cycle and transcriptional networks are important in this process. MADS-box genes are key developmental regulators in eukaryotes, but their role in cell proliferation and differentiation modulation in plants remains poorly studied. Methods We characterize the XAL1 loss-of-function xal1-2 allele and overexpression lines using quantitative cellular and cytometry analyses to explore its role in cell cycle, proliferation, stem-cell patterning and transition to differentiation. We used quantitative PCR and cellular markers to explore if XAL1 regulates cell-cycle components and PLETHORA1 (PLT1) gene expression, as well as confocal microscopy to analyse stem-cell niche organization. Key Results We previously showed that XAANTAL1 (XAL1/AGL12) is necessary for Arabidopsis root development as a promoter of cell proliferation in the root apical meristem. Here, we demonstrate that XAL1 positively regulates the expression of PLT1 and important components of the cell cycle: CYCD3;1, CYCA2;3, CYCB1;1, CDKB1;1 and CDT1a. In addition, we show that xal1-2 mutant plants have a premature transition to differentiation with root hairs appearing closer to the root tip, while endoreplication in these plants is partially compromised. Coincidently, the final size of cortex cells in the mutant is shorter than wild-type cells. Finally, XAL1 overexpression-lines corroborate that this transcription factor is able to promote cell proliferation at the stem-cell niche. Conclusion XAL1 seems to be an important component of the networks that modulate cell proliferation/differentiation transition and stem-cell proliferation during Arabidopsis root development; it also regulates several cell-cycle components. PMID:27474508

The Tribolium homeotic gene Abdominal is homologous to abdominal-A of the Drosophila bithorax complex

NASA Technical Reports Server (NTRS)

Stuart, J. J.; Brown, S. J.; Beeman, R. W.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

1993-01-01

The Abdominal gene is a member of the single homeotic complex of the beetle, Tribolium castaneum. An integrated developmental genetic and molecular analysis shows that Abdominal is homologous to the abdominal-A gene of the bithorax complex of Drosophila. abdominal-A mutant embryos display strong homeotic transformations of the anterior abdomen (parasegments 7-9) to PS6, whereas developmental commitments in the posterior abdomen depend primarily on Abdominal-B. In beetle embryos lacking Abdominal function, parasegments throughout the abdomen are transformed to PS6. This observation demonstrates the general functional significance of parasegmental expression among insects and shows that the control of determinative decisions in the posterior abdomen by homeotic selector genes has undergone considerable evolutionary modification.

The Tribolium homeotic gene Abdominal is homologous to abdominal-A of the Drosophila bithorax complex.

PubMed

Stuart, J J; Brown, S J; Beeman, R W; Denell, R E

1993-01-01

The Abdominal gene is a member of the single homeotic complex of the beetle, Tribolium castaneum. An integrated developmental genetic and molecular analysis shows that Abdominal is homologous to the abdominal-A gene of the bithorax complex of Drosophila. abdominal-A mutant embryos display strong homeotic transformations of the anterior abdomen (parasegments 7-9) to PS6, whereas developmental commitments in the posterior abdomen depend primarily on Abdominal-B. In beetle embryos lacking Abdominal function, parasegments throughout the abdomen are transformed to PS6. This observation demonstrates the general functional significance of parasegmental expression among insects and shows that the control of determinative decisions in the posterior abdomen by homeotic selector genes has undergone considerable evolutionary modification.

Metamorphosis in the Cirripede Crustacean Balanus amphitrite

PubMed Central

Maruzzo, Diego; Aldred, Nick; Clare, Anthony S.; Høeg, Jens T.

2012-01-01

Stalked and acorn barnacles (Cirripedia Thoracica) have a complex life cycle that includes a free-swimming nauplius larva, a cypris larva and a permanently attached sessile juvenile and adult barnacle. The barnacle cyprid is among the most highly specialized of marine invertebrate larvae and its settlement biology has been intensively studied. By contrast, surprisingly few papers have dealt with the critical series of metamorphic events from cementation of the cyprid to the substratum until the appearance of a suspension feeding juvenile. This metamorphosis is both ontogenetically complex and critical to the survival of the barnacle. Here we use video microscopy to present a timeline and description of morphological events from settled cyprid to juvenile barnacle in the model species Balanus amphitrite, representing an important step towards both a broader understanding of the settlement ecology of this species and a platform for studying the factors that control its metamorphosis. Metamorphosis in B. amphitrite involves a complex sequence of events: cementation, epidermis separation from the cypris cuticle, degeneration of cypris musculature, rotation of the thorax inside the mantle cavity, building of the juvenile musculature, contraction of antennular muscles, raising of the body, shedding of the cypris cuticle, shell plate and basis formation and, possibly, a further moult to become a suspension feeding barnacle. We compare these events with developmental information from other barnacle species and discuss them in the framework of barnacle settlement ecology. PMID:22666355

DNA Replication Control During Drosophila Development: Insights into the Onset of S Phase, Replication Initiation, and Fork Progression

PubMed Central

Hua, Brian L.; Orr-Weaver, Terry L.

2017-01-01

Proper control of DNA replication is critical to ensure genomic integrity during cell proliferation. In addition, differential regulation of the DNA replication program during development can change gene copy number to influence cell size and gene expression. Drosophila melanogaster serves as a powerful organism to study the developmental control of DNA replication in various cell cycle contexts in a variety of differentiated cell and tissue types. Additionally, Drosophila has provided several developmentally regulated replication models to dissect the molecular mechanisms that underlie replication-based copy number changes in the genome, which include differential underreplication and gene amplification. Here, we review key findings and our current understanding of the developmental control of DNA replication in the contexts of the archetypal replication program as well as of underreplication and differential gene amplification. We focus on the use of these latter two replication systems to delineate many of the molecular mechanisms that underlie the developmental control of replication initiation and fork elongation. PMID:28874453

A BIOLOGICALLY BASED MODEL FOR THE HORMONAL CONTROL OF THE MENSTRUAL CYCLE

EPA Science Inventory

Recent studies suggest that environmental substances that mimic endogenous estrogens (eg. estradiol) may disrupt the endocrine system. While high-level exposures to estrogenic substances are believed to contribute to such adverse effects as cancer, developmental disorders, and fe...

Report of the NASA Mammalian Developmental Biology Working Group

NASA Technical Reports Server (NTRS)

Keefe, J. R.

1985-01-01

Development is considered to encompass all aspects of the mammalian life span from initial initial germ cell production through the complete life cycle to death of the organism. Thus, gamete production, fertilization, embryogenesis, implantation, fetogenesis, birth, peri- and postnatal maturation, and aging were all considered as stages of a development continuum relevant to problems of Space Biology. Deliberations thus far have been limited to stages of the development cycle from fertilization to early postnatal life. The deliberations are detailed.

Androgen Receptor-Mediated Growth Suppression of HPr-1AR and PC3-Lenti-AR Prostate Epithelial Cells

PubMed Central

Bolton, Eric C.

2015-01-01

The androgen receptor (AR) mediates the developmental, physiologic, and pathologic effects of androgens including 5α-dihydrotestosterone (DHT). However, the mechanisms whereby AR regulates growth suppression and differentiation of luminal epithelial cells in the prostate gland and proliferation of malignant versions of these cells are not well understood, though they are central to prostate development, homeostasis, and neoplasia. Here, we identify androgen-responsive genes that restrain cell cycle progression and proliferation of human prostate epithelial cell lines (HPr-1AR and PC3-Lenti-AR), and we investigate the mechanisms through which AR regulates their expression. DHT inhibited proliferation of HPr-1AR and PC3-Lenti-AR, and cell cycle analysis revealed a prolonged G1 interval. In the cell cycle, the G1/S-phase transition is initiated by the activity of cyclin D and cyclin-dependent kinase (CDK) complexes, which relieve growth suppression. In HPr-1AR, cyclin D1/2 and CDK4/6 mRNAs were androgen-repressed, whereas CDK inhibitor, CDKN1A, mRNA was androgen-induced. The regulation of these transcripts was AR-dependent, and involved multiple mechanisms. Similar AR-mediated down-regulation of CDK4/6 mRNAs and up-regulation of CDKN1A mRNA occurred in PC3-Lenti-AR. Further, CDK4/6 overexpression suppressed DHT-inhibited cell cycle progression and proliferation of HPr-1AR and PC3-Lenti-AR, whereas CDKN1A overexpression induced cell cycle arrest. We therefore propose that AR-mediated growth suppression of HPr-1AR involves cyclin D1 mRNA decay, transcriptional repression of cyclin D2 and CDK4/6, and transcriptional activation of CDKN1A, which serve to decrease CDK4/6 activity. AR-mediated inhibition of PC3-Lenti-AR proliferation occurs through a similar mechanism, albeit without down-regulation of cyclin D. Our findings provide insight into AR-mediated regulation of prostate epithelial cell proliferation. PMID:26372468

Attachment in integrative neuroscientific perspective.

PubMed

Hruby, Radovan; Hasto, Jozef; Minarik, Peter

2011-01-01

Attachment theory is a very influential general concept of human social and emotional development, which emphasizes the role of early mother-infant interactions for infant's adaptive behavioural and stress copying strategies, personality organization and mental health. Individuals with disrupted development of secure attachment to mother/primary caregiver are at higher risk of developing mental disorders. This theory consists of the complex developmental psycho-neurobiological model of attachment and emerges from principles of psychoanalysis, evolutionary biology, cognitive-developmental psychology, ethology, physiology and control systems theory. The progress of modern neuroscience enables interpretation of neurobiological aspects of the theory as multi-level neural interactions and functional development of important neural structures, effects of neuromediattors, hormones and essential neurobiological processes including emotional, cognitive, social interactions and the special key role of mentalizing. It has multiple neurobiological, neuroendocrine, neurophysiological, ethological, genetic, developmental, psychological, psychotherapeutic and neuropsychiatric consequences and is a prototype of complex neuroscientific concept as interpretation of modern integrated neuroscience.

Knowledge Cannot Explain the Developmental Growth of Working Memory Capacity

ERIC Educational Resources Information Center

Cowan, Nelson; Ricker, Timothy J.; Clark, Katherine M.; Hinrichs, Garrett A.; Glass, Bret A.

2015-01-01

According to some views of cognitive growth, the development of working memory capacity can account for increases in the complexity of cognition. It has been difficult to ascertain, though, that there actually is developmental growth in capacity that cannot be attributed to other developing factors. Here we assess the role of item familiarity. We…

Integrating Technology in the Classroom: Factors That Account for Teachers' Regressive Developmental Trajectories

ERIC Educational Resources Information Center

Looi, Chee-Kit; Chen, Wenli; Chen, Fang-Hao

2014-01-01

In this article, we studied the developmental trajectories of three teachers as they integrated GroupScribbles (GS) technology in their classroom lessons over a semester period of about 5 months. Coherency diagrams were used to capture the complex interplay of a teacher's knowledge (K), goals (G) and beliefs (B) in leveraging technology…

Metacognition in Speech and Language Therapy for Children with Social (Pragmatic) Communication Disorders: Implications for a Theory of Therapy

ERIC Educational Resources Information Center

Gaile, Jacqueline; Adams, Catherine

2018-01-01

Background: Metacognition is a significant component of complex interventions for children who have developmental language disorders. Research into how metacognition operates in the content or process of developmental language therapy delivery is limited. Identification and description of proposed active therapy components, such as metacognition,…

Mapping the Developmental Trajectory and Correlates of Enhanced Pitch Perception on Speech Processing in Adults with ASD

ERIC Educational Resources Information Center

Mayer, Jennifer L.; Hannent, Ian; Heaton, Pamela F.

2016-01-01

Whilst enhanced perception has been widely reported in individuals with Autism Spectrum Disorders (ASDs), relatively little is known about the developmental trajectory and impact of atypical auditory processing on speech perception in intellectually high-functioning adults with ASD. This paper presents data on perception of complex tones and…

Slow Perceptual Processing at the Core of Developmental Dyslexia: A Parameter-Based Assessment of Visual Attention

ERIC Educational Resources Information Center

Stenneken, Prisca; Egetemeir, Johanna; Schulte-Korne, Gerd; Muller, Hermann J.; Schneider, Werner X.; Finke, Kathrin

2011-01-01

The cognitive causes as well as the neurological and genetic basis of developmental dyslexia, a complex disorder of written language acquisition, are intensely discussed with regard to multiple-deficit models. Accumulating evidence has revealed dyslexics' impairments in a variety of tasks requiring visual attention. The heterogeneity of these…

In-Service Assistive Technology Training to Support People with Intellectual and Developmental Disabilities: A Case Study

ERIC Educational Resources Information Center

Haynes, Scott

2013-01-01

Assistive technology (AT) benefits many individuals with intellectual and developmental disabilities (IDD). The appropriate application of accommodation solutions, whether they involve the use of AT or not, can be a complex process involving a team of people with various backgrounds. This article describes an in-service AT training program that…

SNAT2 and LAT1 transporter abundance is developmentally regulated in skeletal muscle of neonatal pigs

USDA-ARS?s Scientific Manuscript database

Previously, we demonstrated that the insulin and amino acid–induced activation of the mammalian target of rapamycin complex 1 (mTORC1), is developmentally regulated in neonatal pigs. Recent studies have indicated an important role of the System A transporters (SNAT2 and SLC1A5) and the L transporter...

Developmental outcomes of Down syndrome and Dandy-Walker malformation

PubMed Central

Love, Kaitlin; Huddleston, Lillie; Olney, Pat; Wrubel, David; Visootsak, Jeannie

2012-01-01

Dandy-Walker syndrome (DWS), or Dandy-Walker complex, is a congenital brain malformation of the posterior fossa, typically resulting in developmental delay and cognitive disability. The co-occurrence of Down syndrome (DS) and DWS is relatively uncommon; thus, its impact on developmental outcomes has not been fully elucidated. Herein, we report a case of a 37-month-old child with DS and DWS, who is functioning at the following age-equivalent: gross motor at a 9-mo level, fine motor 6 mo, expressive language 14 mo, receptive language 9 mo. As such, it is important to determine how the DWS influences developmental outcomes, and appreciate the importance of early interventional therapy. PMID:22866020

Growing up in the Ocean: Complex Life Cycles of Common Marine Invertebrates

ERIC Educational Resources Information Center

Bennett, Katie; Hiebert, Laurel

2010-01-01

Most people are familiar with the concept that animals come in all shapes and sizes and that the body plan of some animals can completely transform during their lifetime. Well-known examples of such complex life cycles of terrestrial animals include butterflies and frogs. Many people are unaware, however, that complex life cycles are exceedingly…

From Continuous Improvement to Organisational Learning: Developmental Theory.

ERIC Educational Resources Information Center

Murray, Peter; Chapman, Ross

2003-01-01

Explores continuous improvement methods, which underlie total quality management, finding barriers to implementation in practice that are related to a one-dimensional approach. Suggests a multiple, unbounded learning cycle, a holistic approach that includes adaptive learning, learning styles, generative learning, and capability development.…

Developmental Control of Cell-Cycle Compensation Provides a Switch for Patterned Mitosis at the Onset of Chordate Neurulation.

PubMed

Ogura, Yosuke; Sasakura, Yasunori

2016-04-18

During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.

Evidence for the presence of a mammalian-like cholinesterase in Paramecium primaurelia (Protista, Ciliophora) developmental cycle.

PubMed

Delmonte Corrado, M U; Politi, H; Trielli, F; Angelini, C; Falugi, C

1999-01-01

By histochemical and immunohistochemical methods, the presence of cholinergic-like molecules has previously been demonstrated in Paramecium primaurelia, and their functional role in mating-cell pairing was suggested. In this work, both true acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities were electrophoretically investigated, and the presence of molecules immunologically related to BuChE was checked by immunoblotting. The AChE activity, shown in the membrane protein fraction of mating-competent cells and in the cytoplasmic fraction of immature cells, is due to a 260-kDa molecular form, similar to the membrane-bound tetrameric form present in human erythrocytes. This AChE activity does not appear in either the cytoplasmic fraction of mating-competent cells or in the membrane protein fraction of immature cells. No evidence was found for the presence or the activity of BuChE-like molecules. The role of AChE in P. primaurelia developmental cycle is discussed.

Temporal remodeling of the cell cycle accompanies differentiation in the Drosophila germline.

PubMed

Hinnant, Taylor D; Alvarez, Arturo A; Ables, Elizabeth T

2017-09-01

Development of multicellular organisms relies upon the coordinated regulation of cellular differentiation and proliferation. Growing evidence suggests that some molecular regulatory pathways associated with the cell cycle machinery also dictate cell fate; however, it remains largely unclear how the cell cycle is remodeled in concert with cell differentiation. During Drosophila oogenesis, mature oocytes are created through a series of precisely controlled division and differentiation steps, originating from a single tissue-specific stem cell. Further, germline stem cells (GSCs) and their differentiating progeny remain in a predominantly linear arrangement as oogenesis proceeds. The ability to visualize the stepwise events of differentiation within the context of a single tissue make the Drosophila ovary an exceptional model for study of cell cycle remodeling. To describe how the cell cycle is remodeled in germ cells as they differentiate in situ, we used the Drosophila Fluorescence Ubiquitin-based Cell Cycle Indicator (Fly-FUCCI) system, in which degradable versions of GFP::E2f1 and RFP::CycB fluorescently label cells in each phase of the cell cycle. We found that the lengths of the G1, S, and G2 phases of the cell cycle change dramatically over the course of differentiation, and identified the 4/8-cell cyst as a key developmental transition state in which cells prepare for specialized cell cycles. Our data suggest that the transcriptional activator E2f1, which controls the transition from G1 to S phase, is a key regulator of mitotic divisions in the early germline. Our data support the model that E2f1 is necessary for proper GSC proliferation, self-renewal, and daughter cell development. In contrast, while E2f1 degradation by the Cullin 4 (Cul4)-containing ubiquitin E3 ligase (CRL4) is essential for developmental transitions in the early germline, our data do not support a role for E2f1 degradation as a mechanism to limit GSC proliferation or self-renewal. Taken together, these findings provide further insight into the regulation of cell proliferation and the acquisition of differentiated cell fate, with broad implications across developing tissues. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparative proteomic analysis provides insight into the biological role of protein phosphatase inhibitor-2 from Arabidopsis.

PubMed

Ahsan, Nagib; Chen, Mingjie; Salvato, Fernanda; Wilson, Rashaun S; Shyama Prasad Rao, R; Thelen, Jay J

2017-08-08

Protein phosphatase inhibitor-2 (PPI-2) is a conserved eukaryotic effector protein that inhibits type one protein phosphatases (TOPP). A transfer-DNA knockdown of AtPPI-2 resulted in stunted growth in both vegetative and reproductive phases of Arabidopsis development. At the cellular level, AtPPI-2 knockdown had 35 to 40% smaller cells in developing roots and leaves. This developmental phenotype was rescued by transgenic expression of the AtPPI-2 cDNA behind a constitutive promoter. Comparative proteomics of developing leaves of wild type (WT) and AtPPI-2 mutant revealed reduced levels of proteins associated with chloroplast development, ribosome biogenesis, transport, and cell cycle regulation processes. Decreased abundance of several ribosomal proteins, a DEAD box RNA helicase family protein (AtRH3), Clp protease (ClpP3) and proteins associated with cell division suggests a bottleneck in chloroplast ribosomal biogenesis and cell cycle regulation in AtPPI-2 mutant plants. In contrast, eight out of nine Arabidopsis TOPP isoforms were increased at the transcript level in AtPPI-2 leaves compared to WT. A protein-protein interaction network revealed that >75% of the differentially accumulated proteins have at least secondary and/or tertiary connections with AtPPI-2. Collectively, these data reveal a potential basis for the growth defects of AtPPI-2 and support the presumed role of AtPPI-2 as a master regulator for TOPPs, which regulate diverse growth and developmental processes. Comparative label-free proteomics was used to characterize an AtPPI-2T-DNA knockdown mutant. The complex, reduced growth phenotype supports the notion that AtPPI-2 is a global regulator of TOPPs, and possibly other proteins. Comparative proteomics revealed a range of differences in protein abundance from various cellular processes such as chloroplast development, ribosome biogenesis, and transporter activity in the AtPPI-2 mutant relative to WT Arabidopsis. Collectively the results of proteomic analysis and the protein-protein network suggest that AtPPI-2 is involved in a wide range of biological processes either directly or indirectly including plastid biogenesis, translational mechanisms, and cell cycle regulation. The proposed protein interaction network comprises a testable model underlying changes in protein abundance in the AtPPI-2 mutant, and provides a better framework for future studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Geographic variation and evolution in the life cycle of the witch-hazel leaf gall aphid, Hormaphis hamamelidis.

PubMed

von Dohlen, C D; Gill, D E

1989-02-01

Two divergent life cycles associated with different elevations and latitudes have been documented for the witch-hazel leaf gall aphid, Hormaphis hamamelidis. At low elevation in northern Virginia, the aphid had seven distinct generations alternating between the primary host, witchhazel (Hamamelis virginiana), and a secondary host, river birch (Betula nigra). These findings confirm the original published life cycle description for the same locality. A second, abbreviated life cycle consisting of only three generations restricted to witch-hazel was discovered at high elevation (1000 m) in north central and northwestern Virginia. Aphids of both life cycles were sympatric at a middle elevation site. The life cycles and morphology suggest that the two forms are separate species. Although monoecious life cycles on primary hosts in aphids generally are thought to be ancestral to complex host-alternating ones, it is certainly possible that monoecious cycles are sometimes secondarily derived from complex cycles. By constructing a preliminary phylogeny of the described species in the tribe Hormaphidini, we propose that the abbreviated life cycle is derived from the complex one in the case of these witchhazel gall aphids. Our findings are discussed in the context of current theory regarding the evolutionary stability of complex life cycles.

The PsB glycoprotein complex is secreted as a preassembled precursor of the spore coat in Dictyostelium discoideum.

PubMed

Watson, N; McGuire, V; Alexander, S

1994-09-01

The PsB glycoprotein in Dictyostelium discoideum is one of a diverse group of developmentally regulated, prespore-cell-specific proteins, that contain a common O-linked oligosaccharide. This post-translational modification is dependent on the wild-type modB allele. The PsB protein exists as part of a multiprotein complex of six different proteins, which have different post-translational modifications and are held together by both covalent and non-covalent interactions (Watson et al. (1993). J. Biol. Chem. 268, 22634-22641). In this study we have used microscopic and biochemical analyses to examine the cellular localization and function of the PsB complex during development. We found that the PsB complex first accumulates in prespore vesicles in slug cells and is secreted later during culmination and becomes localized to both the extracellular matrix of the apical spore mass of mature fruiting bodies and to the inner layer of the spore coat. The PsB associated with the spore coat is covalently bound by disulfide bridges. The PsB protein always exists in a multiprotein complex, but the composition of the PsB complex changes during secretion and spore maturation. Some of the PsB complex proteins have been identified as spore coat proteins. These data demonstrate that some of the proteins that form the spore coat exist as a preassembled precursor complex. The PsB complex is secreted in a developmentally regulated manner during the process of spore differentiation, at which time proteins of the complex, as well as additional spore coat proteins, become covalently associated in at least two forms of extracellular matrix: the interspore matrix and the spore coat. These and other studies show that proteins with modB dependent O-linked oligosaccharides are involved in a wide variety of processes underlying morphogenesis in this organism. These developmental processes are the direct result of cellular mechanisms regulating protein targeting, assembly and secretion, and the assembly of specific extracellular matrices.

Identification of early indicators of altered metabolism in normal development using a rodent model system.

PubMed

Prabakaran, Ashok Daniel; Karakkat, Jimsheena Valiyakath; Vijayan, Ranjit; Chalissery, Jisha; Ibrahim, Marwa F; Kaimala, Suneesh; Adeghate, Ernest A; Al-Marzouqi, Ahmed Hassan; Ansari, Suraiya Anjum; Mensah-Brown, Eric; Emerald, Bright Starling

2018-03-01

Although the existence of a close relationship between the early maternal developmental environment, fetal size at birth and the risk of developing disease in adulthood has been suggested, most studies, however, employed experimentally induced intrauterine growth restriction as a model to link this with later adult disease. Because embryonic size variation also occurs under normal growth and differentiation, elucidating the molecular mechanisms underlying these changes and their relevance to later adult disease risk becomes important. The birth weight of rat pups vary according to the uterine horn positions. Using birth weight as a marker, we compared two groups of rat pups - lower birth weight (LBW, 5th to 25th percentile) and average birth weight (ABW, 50th to 75th percentile) - using morphological, biochemical and molecular biology, and genetic techniques. Our results show that insulin metabolism, Pi3k/Akt and Pparγ signaling and the genes regulating growth and metabolism are significantly different in these groups. Methylation at the promoter of the InsII ( Ins2 ) gene and DNA methyltransferase 1 in LBW pups are both increased. Additionally, the Dnmt1 repressor complex, which includes Hdac1, Rb (Rb1) and E2f1, was also upregulated in LBW pups. We conclude that the Dnmt1 repressor complex, which regulates the restriction point of the cell cycle, retards the rate at which cells traverse the G1 or G0 phase of the cell cycle in LBW pups, thereby slowing down growth. This regulatory mechanism mediated by Dnmt1 might contribute to the production of small-size pups and altered physiology and pathology in adult life. © 2018. Published by The Company of Biologists Ltd.

Identification of early indicators of altered metabolism in normal development using a rodent model system

PubMed Central

Prabakaran, Ashok Daniel; Karakkat, Jimsheena Valiyakath; Chalissery, Jisha; Ibrahim, Marwa F.; Kaimala, Suneesh; Adeghate, Ernest A.; Al-Marzouqi, Ahmed Hassan; Ansari, Suraiya Anjum

2018-01-01

ABSTRACT Although the existence of a close relationship between the early maternal developmental environment, fetal size at birth and the risk of developing disease in adulthood has been suggested, most studies, however, employed experimentally induced intrauterine growth restriction as a model to link this with later adult disease. Because embryonic size variation also occurs under normal growth and differentiation, elucidating the molecular mechanisms underlying these changes and their relevance to later adult disease risk becomes important. The birth weight of rat pups vary according to the uterine horn positions. Using birth weight as a marker, we compared two groups of rat pups – lower birth weight (LBW, 5th to 25th percentile) and average birth weight (ABW, 50th to 75th percentile) – using morphological, biochemical and molecular biology, and genetic techniques. Our results show that insulin metabolism, Pi3k/Akt and Pparγ signaling and the genes regulating growth and metabolism are significantly different in these groups. Methylation at the promoter of the InsII (Ins2) gene and DNA methyltransferase 1 in LBW pups are both increased. Additionally, the Dnmt1 repressor complex, which includes Hdac1, Rb (Rb1) and E2f1, was also upregulated in LBW pups. We conclude that the Dnmt1 repressor complex, which regulates the restriction point of the cell cycle, retards the rate at which cells traverse the G1 or G0 phase of the cell cycle in LBW pups, thereby slowing down growth. This regulatory mechanism mediated by Dnmt1 might contribute to the production of small-size pups and altered physiology and pathology in adult life. PMID:29434026

Influence of Orientia tsutsugamushi infection on the developmental biology of Leptotrombidium imphalum and Leptotrombidium chiangraiensis (Acari: Trombiculidae).

PubMed

Phasomkusolsil, Siriporn; Tanskul, Panita; Ratanatham, Supaporn; Watcharapichat, Pochaman; Phulsuksombati, Duangporn; Frances, Stephen P; Lerdthusnee, Kriangkrai; Linthicum, Kenneth J

2012-11-01

Leptotrombidium chiangraiensis Tanskul & Linthicum, and Leptotrombidium imphalum Vercammen-Grandjean are important vectors of scrub typhus in rice field habitats in northern Thailand. The developmental biology of all stages of the life cycle of two generations of these species of mites infected with Orientia tsutsugamushi (Hayashi) and uninfected mites is reported. The development of the infected lines of both F1 and F2 L. chiangraiensis were significantly longer than their respective uninfected lines (P < 0.05). The developmental times of uninfected and infected F1 lines of L. imphalum were not significantly different; however, F2 infected lines took significantly longer to develop (P < 0.05). Both F1 and F2 generations of infected L. imphalum and L. chiangraiensis oviposited on average >150 fewer eggs than uninfected mites.

Primer and interviews: Molecular mechanisms of morphological evolution

PubMed Central

Kiefer, Julie C

2010-01-01

The beauty of the developing embryo, and the awe that it inspires, lure many scientists into the field of developmental biology. What compels cells to divide, migrate, and morph into a being with a complex body plan? Evolutionary developmental biologists hold similar fascinations, with dynamics that take place on a grander timescale. How do phenotypic traits diverge over evolutionary time? This primer illustrates how a deep understanding of the basic principles that underlie developmental biology have changed how scientists think about the evolution of body form. The primer culminates in a conversation with David Stern, PhD, and Michael Shapiro, PhD, who discuss current topics in morphological evolution, why the field should be of interest to classic developmental biologists, and what lies ahead. Developmental Dynamics 239:3497–3505, 2010. © 2010 Wiley-Liss, Inc. PMID:21069831

Developmental perspectives on nutrition and obesity from gestation to adolescence.

PubMed

Esposito, Layla; Fisher, Jennifer O; Mennella, Julie A; Hoelscher, Deanna M; Huang, Terry T

2009-07-01

Obesity results from a complex combination of factors that act at many stages throughout a person's life. Therefore, examining childhood nutrition and obesity from a developmental perspective is warranted. A developmental perspective recognizes the cumulative effects of factors that contribute to eating behavior and obesity, including biological and socioenvironmental factors that are relevant at different stages of development. A developmental perspective considers family, school, and community context. During gestation, risk factors for obesity include maternal diet, overweight, and smoking. In early childhood, feeding practices, taste acquisition, and eating in the absence of hunger must be considered. As children become more independent during middle childhood and adolescence, school nutrition, food marketing, and social networks become focal points for obesity prevention or intervention. Combining a multilevel approach with a developmental perspective can inform more effective and sustainable strategies for obesity prevention.

Knowledge Cannot Explain the Developmental Growth of Working Memory Capacity

PubMed Central

Cowan, Nelson; Ricker, Timothy J.; Clark, Katherine M.; Hinrichs, Garrett A.; Glass, Bret A.

2014-01-01

According to some views of cognitive growth, the development of working memory capacity can account for increases in the complexity of cognition. It has been difficult to ascertain, though, that there actually is developmental growth in capacity that cannot be attributed to other developing factors. Here we assess the role of item familiarity. We document developmental increases in working memory for visual arrays of English letters versus unfamiliar characters. Although letter knowledge played a special role in development between the ages of 6 to 8 years, children with adequate letter knowledge showed practically the same developmental growth in normalized functions for letters and unfamiliar characters. The results contribute to a growing body of evidence that the developmental improvement in working memory does not wholly stem from supporting processes such as encoding, mnemonic strategies, and knowledge. PMID:24942111

Sometimes "Newton's Method" Always "Cycles"

ERIC Educational Resources Information Center

Latulippe, Joe; Switkes, Jennifer

2012-01-01

Are there functions for which Newton's method cycles for all non-trivial initial guesses? We construct and solve a differential equation whose solution is a real-valued function that two-cycles under Newton iteration. Higher-order cycles of Newton's method iterates are explored in the complex plane using complex powers of "x." We find a class of…

[Effect of spermatozoa from different sources on normal fertilization of oocytes and embryo quality and development in intracytoplasmic sperm injection cycles].

PubMed

Xie, Duo; Qiu, Zhuolin; Luo, Chen; Chu, Qingjun; Quan, Song

2014-06-01

To evaluate the impact of spermatozoa from different sources on normal fertilization of oocytes, embryo quality and embryo developmental potential in intracytoplasmic sperm injection (ICSI) cycles. A retrospective analysis was conducted among 197 patients undergoing ICSI cycles in our center. The patients were classified into 3 groups according to the sources of semen, namely ejaculated spermatozoa group (n=102), percutaneous epididymal sperm aspiration (PESA) group (n=68), and testicular sperm aspiration (TESA) group (n=27). The ejaculated spermatozoa group was further classified into oligoasthenoteratozoospermia (n=67) and cryptozoospermia (n=35) subgroups. The normal fertilization, high-quality embryo, implantation and clinical pregnancy rates were compared among the groups; the rate of high-quality blastocyst formation in in-vitro culture of non-top quality embryos was also observed. The patients with PESA showed significantly higher normal fertilization rate (75.6%) than those in oligoasthenoteratozoospermia (64.8%), cryptozoospermia (62.1%), and TESA (61.6%) groups (P<0.05). No significant differences were found in the high-quality embryo, implantation, and clinical pregnancy rates among the groups (P>0.05). The rate of high-quality blastocyst formation in the in-vitro culture of non-top quality embryos was also comparable among the groups (P>0.05). Although spermatozoa obtained with by PESA is associated with a higher normal fertilization rate, the sources of spermatozoa do not significantly affect the embryonic quality and developmental potential in ICSI cycles.

Attainment of gross motor milestones in children with Down syndrome in Kosovo - developmental perspective.

PubMed

Beqaj, Samire; Jusaj, Njomza; Živković, Vujica

2017-08-01

Aim To investigate the age (in months) at which motor skills are developed in children with Down syndrome (DS), and compare it to the age of the development of the same skills in both, children with typical development (TD), and children with DS reported by four other studies. Methods Sixteen children (7 girls and 9 boys) were monthly assessed for the development of nineteen motor skills between 2008 and 2011. The mean ages when the skills were accomplished were presented using descriptive statistics. Independent T-samples test (significance < 0.05) was used to compare the mean developmental ages from our study with those seen in children with TD (Comparison 1) and also in children with DS reported by four other authors (Comparison 2a-2d). Results Children with DS developed at a significantly slower pace compared to children with TD (p=0.005). Generally, delay and variance of developmental age in children with DS increased chronologically with the complexity of the skills. No significant difference was found between developmental age in children from the present study and children with DS from other studies. Conclusion The rate of attainment of motor skills is delayed in children with DS in comparison to children with TD, however, the developmental sequence is the same. The delayed development is more prominent in more complex skills. Copyright© by the Medical Assotiation of Zenica-Doboj Canton.

Comparison of Measures of Morphosyntactic Complexity in French-Speaking School-Aged Children

ERIC Educational Resources Information Center

Mimeau, Catherine; Plourde, Vickie; Ouellet, Andrée-Anne; Dionne, Ginette

2015-01-01

This study examined the validity and reliability of different measures of morphosyntactic complexity, including the Morphosyntactic Complexity Scale (MSCS), a novel adaptation of the Developmental Sentence Scoring, in French-speaking school-aged children. Seventy-three Quebec children from kindergarten to Grade 3 completed a definition task and a…

Development and Example Application of a Pilot Model for the Biogeochemical Cycling of Mercury in Watersheds: SERAFM-NPS

EPA Science Inventory

Mercury is a developmental neurotoxicant, ubiquitous in the environment, existing both naturally and through anthropogenic additions, resulting in human and ecological exposure risks primarily via consumption of mercury contaminated fish tissue. To better understand the risk ass...

Knowledge Is Power. Research Can Help Your Marketing Program Succeed.

ERIC Educational Resources Information Center

Smith, Robert M.

1982-01-01

Three major types of market research can be helpful in college marketing: exploratory (internal and external to the college); developmental, to test marketing strategies and messages; and evaluative, to complete the market planning cycle. Increasingly sophisticated and accountable marketing techniques can be developed. (MSE)

Isolation, Culture and Cryopreservation of Sarcocystis species

USDA-ARS?s Scientific Manuscript database

More than 200 valid Sarcocystis species have been described in the parasitological literature. The developmental life cycle in the intermediate host and definitive host has only been described for a few species. The majority of species have been identified based solely on the presence of the sarcocy...

On the interrelation of multiplication and division in secondary school children.

PubMed

Huber, Stefan; Fischer, Ursula; Moeller, Korbinian; Nuerk, Hans-Christoph

2013-01-01

Each division problem can be transformed into as a multiplication problem and vice versa. Recent research has indicated strong developmental parallels between multiplication and division in primary school children. In this study, we were interested in (i) whether these developmental parallels persist into secondary school, (ii) whether similar developmental parallels can be observed for simple and complex problems, (iii) whether skill level modulates this relationship, and (iv) whether the correlations are specific and not driven by general cognitive or arithmetic abilities. Therefore, we assessed performance of 5th and 6th graders attending two secondary school types of the German educational system in simple and complex multiplication as well as division while controlling for non-verbal intelligence, short-term memory, and other arithmetic abilities. Accordingly, we collected data from students differing in skills levels due to either age (5th < 6th grade) or school type (general < intermediate secondary school). We observed moderate to strong bivariate and partial correlations between multiplication and division with correlations being higher for simple tasks but nevertheless reliable for complex tasks. Moreover, the association between simple multiplication and division depended on students' skill levels as reflected by school types, but not by age. Partial correlations were higher for intermediate than for general secondary school children. In sum, these findings emphasize the importance of the inverse relationship between multiplication and division which persists into later developmental stages. However, evidence for skill-related differences in the relationship between multiplication and division was restricted to the differences for school types.

On triatomines, cockroaches and haemolymphagy under laboratory conditions: new discoveries

PubMed Central

Durán, Pamela; Siñani, Edda; Depickère, Stéphanie

2016-01-01

For a long time, haematophagy was considered an obligate condition for triatomines (Hemiptera: Reduviidae) to complete their life cycle. Today, the ability to use haemolymphagy is suggested to represent an important survival strategy for some species, especially those in genus Belminus. As Eratyrus mucronatus and Triatoma boliviana are found with cockroaches in the Blaberinae subfamily in Bolivia, their developmental cycle from egg to adult under a “cockroach diet” was studied. The results suggested that having only cockroach haemolymph as a food source compromised development cycle completion in both species. Compared to a “mouse diet”, the cockroach diet increased: (i) the mortality at each nymphal instar; (ii) the number of feedings needed to molt; (iii) the volume of the maximum food intake; and (iv) the time needed to molt. In conclusion, haemolymph could effectively support survival in the field in both species. Nevertheless, under laboratory conditions, the use of haemolymphagy as a survival strategy in the first developmental stages of these species was not supported, as their mortality was very high. Finally, when Triatoma infestans, Rhodnius stali and Panstrongylus rufotuberculatus species were reared on a cockroach diet under similar conditions, all died rather than feeding on cockroaches. These results are discussed in the context of the ecology of each species. PMID:27706376

Developmental plasticity and the evolution of parasitism in an unusual nematode, Parastrongyloides trichosuri.

PubMed

Stasiuk, Susan J; Scott, Maxwell J; Grant, Warwick N

2012-01-03

Parasitism is an important life history strategy in many metazoan taxa. This is particularly true of the Phylum Nematoda, in which parasitism has evolved independently at least nine times. The apparent ease with which parasitism has evolved amongst nematodes may, in part, be due to a feature of nematode development acting as a pre-adaptation for the transition from a free-living to a parasitic life history. One candidate pre-adaptive feature for evolution in terrestrial nematodes is the dauer larva, a developmentally arrested morph formed in response to environmental signals. We investigated the role of dauer development in the nematode, Parastrongyloides trichosuri, which has retained a complete free-living life cycle in addition to a life cycle as a mammalian gastrointestinal parasite. We show that the developmental switch between these life histories is sensitive to the same environmental cues as dauer arrest in free-living nematodes, including sensitivity to a chemical cue produced by the free-living stages. Furthermore, we show that genetic variation for the sensitivity of the cue(s) exists in natural populations of P. trichosuri, such that we derived inbred lines that were largely insensitive to the cue and other lines that were supersensitive to the cue. For this parasitic clade, and perhaps more widely in the phylum, the evolution of parasitism co-opted the dauer switch of a free-living ancestor. This lends direct support to the hypothesis that the switch to developmental arrest in the dauer larva acted as a pre-adaptation for the evolution of parasitism, and suggests that the sensory transduction machinery downstream of the cue may have been similarly co-opted and modified.

Developmental plasticity and the evolution of parasitism in an unusual nematode, Parastrongyloides trichosuri

PubMed Central

2012-01-01

Background Parasitism is an important life history strategy in many metazoan taxa. This is particularly true of the Phylum Nematoda, in which parasitism has evolved independently at least nine times. The apparent ease with which parasitism has evolved amongst nematodes may, in part, be due to a feature of nematode development acting as a pre-adaptation for the transition from a free-living to a parasitic life history. One candidate pre-adaptive feature for evolution in terrestrial nematodes is the dauer larva, a developmentally arrested morph formed in response to environmental signals. Results We investigated the role of dauer development in the nematode, Parastrongyloides trichosuri, which has retained a complete free-living life cycle in addition to a life cycle as a mammalian gastrointestinal parasite. We show that the developmental switch between these life histories is sensitive to the same environmental cues as dauer arrest in free-living nematodes, including sensitivity to a chemical cue produced by the free-living stages. Furthermore, we show that genetic variation for the sensitivity of the cue(s) exists in natural populations of P. trichosuri, such that we derived inbred lines that were largely insensitive to the cue and other lines that were supersensitive to the cue. Conclusions For this parasitic clade, and perhaps more widely in the phylum, the evolution of parasitism co-opted the dauer switch of a free-living ancestor. This lends direct support to the hypothesis that the switch to developmental arrest in the dauer larva acted as a pre-adaptation for the evolution of parasitism, and suggests that the sensory transduction machinery downstream of the cue may have been similarly co-opted and modified. PMID:22214222

Switching on Flowers: Transient LEAFY Induction Reveals Novel Aspects of the Regulation of Reproductive Development in Arabidopsis

PubMed Central

Wagner, Doris; Meyerowitz, Elliot M.

2011-01-01

Developmental fate decisions in cell populations fundamentally depend on at least two parameters: a signal that is perceived by the cell and the intrinsic ability of the cell to respond to the signal. The same regulatory logic holds for phase transitions in the life cycle of an organism, for example the switch to reproductive development in flowering plants. Here we have tested the response of the monocarpic plant species Arabidopsis thaliana to a signal that directs flower formation, the plant-specific transcription factor LEAFY (LFY). Using transient steroid-dependent LEAFY (LFY) activation in lfy null mutant Arabidopsis plants, we show that the plant’s competence to respond to the LFY signal changes during development. Very early in the life cycle, the plant is not competent to respond to the signal. Subsequently, transient LFY activation can direct primordia at the flanks of the shoot apical meristem to adopt a floral fate. Finally, the plants acquire competence to initiate the flower-patterning program in response to transient LFY activation. Similar to a perennial life strategy, we did not observe reprogramming of all primordia after perception of the transient signal, instead only a small number of meristems responded, followed by reversion to the prior developmental program. The ability to initiate flower formation and to direct flower patterning in response to transient LFY upregulation was dependent on the known direct LFY target APETALA1 (AP1). Prolonged LFY or activation could alter the developmental gradient and bypass the requirement for AP1. Prolonged high AP1 levels, in turn, can also alter the plants’ competence. Our findings shed light on how plants can fine-tune important phase transitions and developmental responses. PMID:22639600

Modulation of Differentiation Processes in Murine Embryonic Stem Cells Exposed to Parabolic Flight-Induced Acute Hypergravity and Microgravity.

PubMed

Acharya, Aviseka; Brungs, Sonja; Henry, Margit; Rotshteyn, Tamara; Singh Yaduvanshi, Nirmala; Wegener, Lucia; Jentzsch, Simon; Hescheler, Jürgen; Hemmersbach, Ruth; Boeuf, Helene; Sachinidis, Agapios

2018-06-15

Embryonic developmental studies under microgravity conditions in space are very limited. To study the effects of short-term altered gravity on embryonic development processes, we exposed mouse embryonic stem cells (mESCs) to phases of hypergravity and microgravity and studied the differentiation potential of the cells using wide-genome microarray analysis. During the 64th European Space Agency's parabolic flight campaign, mESCs were exposed to 31 parabolas. Each parabola comprised phases lasting 22 s of hypergravity, microgravity, and a repeat of hypergravity. On different parabolas, RNA was isolated for microarray analysis. After exposure to 31 parabolas, mESCs (P31 mESCs) were further differentiated under normal gravity (1 g) conditions for 12 days, producing P31 12-day embryoid bodies (EBs). After analysis of the microarrays, the differentially expressed genes were analyzed using different bioinformatic tools to identify developmental and nondevelopmental biological processes affected by conditions on the parabolic flight experiment. Our results demonstrated that several genes belonging to GOs associated with cell cycle and proliferation were downregulated in undifferentiated mESCs exposed to gravity changes. However, several genes belonging to developmental processes, such as vasculature development, kidney development, skin development, and to the TGF-β signaling pathway, were upregulated. Interestingly, similar enriched and suppressed GOs were obtained in P31 12-day EBs compared with ground control 12-day EBs. Our results show that undifferentiated mESCs exposed to alternate hypergravity and microgravity phases expressed several genes associated with developmental/differentiation and cell cycle processes, suggesting a transition from the undifferentiated pluripotent to a more differentiated stage of mESCs.

The unique structural and biochemical development of single cell C4 photosynthesis along longitudinal leaf gradients in Bienertia sinuspersici and Suaeda aralocaspica (Chenopodiaceae)

PubMed Central

Koteyeva, Nuria K.; Voznesenskaya, Elena V.; Berry, James O.; Cousins, Asaph B.; Edwards, Gerald E.

2016-01-01

Temporal and spatial patterns of photosynthetic enzyme expression and structural maturation of chlorenchyma cells along longitudinal developmental gradients were characterized in young leaves of two single cell C4 species, Bienertia sinuspersici and Suaeda aralocaspica. Both species partition photosynthetic functions between distinct intracellular domains. In the C4-C domain, C4 acids are formed in the C4 cycle during capture of atmospheric CO2 by phosphoenolpyruvate carboxylase. In the C4-D domain, CO2 released in the C4 cycle via mitochondrial NAD-malic enzyme is refixed by Rubisco. Despite striking differences in origin and intracellular positioning of domains, these species show strong convergence in C4 developmental patterns. Both progress through a gradual developmental transition towards full C4 photosynthesis, with an associated increase in levels of photosynthetic enzymes. Analysis of longitudinal sections showed undeveloped domains at the leaf base, with Rubisco rbcL mRNA and protein contained within all chloroplasts. The two domains were first distinguishable in chlorenchyma cells at the leaf mid-regions, but still contained structurally similar chloroplasts with equivalent amounts of rbcL mRNA and protein; while mitochondria had become confined to just one domain (proto-C4-D). The C4 state was fully formed towards the leaf tips, Rubisco transcripts and protein were compartmentalized specifically to structurally distinct chloroplasts in the C4-D domains indicating selective regulation of Rubisco expression may occur by control of transcription or stability of rbcL mRNA. Determination of CO2 compensation points showed young leaves were not functionally C4, consistent with cytological observations of the developmental progression from C3 default to intermediate to C4 photosynthesis. PMID:26957565

The Contribution of Novel Brain Imaging Techniques to Understanding the Neurobiology of Mental Retardation and Developmental Disabilities

ERIC Educational Resources Information Center

Gothelf, Doron; Furfaro, Joyce A.; Penniman, Lauren C.; Glover, Gary H.; Reiss, Allan L.

2005-01-01

Studying the biological mechanisms underlying mental retardation and developmental disabilities (MR/DD) is a very complex task. This is due to the wide heterogeneity of etiologies and pathways that lead to MR/DD. Breakthroughs in genetics and molecular biology and the development of sophisticated brain imaging techniques during the last decades…

The Perspective of Young Adult Siblings of Individuals with Asperger Syndrome and High Functioning Autism: An Exploration of Grief and Implications for Developmental Transition

ERIC Educational Resources Information Center

Allgood, Nicole R.

2010-01-01

Asperger syndrome (AS) and high functioning autism are complex developmental disabilities that have a significant impact on the individual and his/her family. Asperger syndrome is characterized by challenges with understanding non-verbal communication, difficulties with social relationships, and restricted interests. Having a brother or sister…

Computer Simulation of Embryonic Systems: What can a virtual embryo teach us about developmental toxicity? Microcephaly: Computational and organotypic modeling of a complex human birth defect (seminar and lecture - Thomas Jefferson University, Philadelphia, PA)

EPA Science Inventory

(1) Standard practice for assessing developmental toxicity is the observation of apical endpoints (intrauterine death, fetal growth retardation, structural malformations) in pregnant rats/rabbits following exposure during organogenesis. EPA’s computational toxicology research pro...

Children's and Adults' Memory for Emotional Pictures: Examining Age-Related Patterns Using the Developmental Affective Photo System

ERIC Educational Resources Information Center

Cordon, Ingrid M.; Melinder, Annika M. D.; Goodman, Gail S.; Edelstein, Robin S.

2013-01-01

Two studies were conducted to examine theoretical questions about children's and adults' memory for emotional visual stimuli. In Study 1, 7- to 9-year-olds and adults (N = 172) participated in the initial creation of the Developmental Affective Photo System (DAPS). Ratings of emotional valence, arousal, and complexity were obtained. In Study 2,…

Syntactic Complexity Effects of Russian Relative Clause Sentences in Children with and without Developmental Language Disorder

ERIC Educational Resources Information Center

Rakhlin, Natalia; Kornilov, Sergey A.; Kornilova, Tatiana V.; Grigorenko, Elena L.

2016-01-01

We investigated relative clause (RC) comprehension in 44 Russian-speaking children with typical language (TD) and developmental language disorder (DLD) (M age = 10;67, SD = 2.84) and 22 adults. Flexible word order and morphological case in Russian allowed us to isolate factors that are obscured in English, helping us to identify sources of…

A Systematic Review of Paraprofessional-Delivered Educational Practices to Improve Outcomes for Students with Intellectual and Developmental Disabilities

ERIC Educational Resources Information Center

Brock, Matthew E.; Carter, Erik W.

2013-01-01

The involvement of paraprofessionals in the education of students with intellectual and developmental disabilities (IDD) has been both complex and controversial. Many scholars and advocates have raised concerns about the roles these staff members play in schools and the degree to which there is empirical support for their direct work with…

Abundance of amino acid transporters involved in mTORC1 activation in skeletal muscle of neonatal pigs is developmentally regulated

USDA-ARS?s Scientific Manuscript database

Previously we demonstrated that the insulinand amino acid-induced activation of the mammalian target of rapamycin complex 1 (mTORC1) is developmentally regulated in neonatal pigs. Recent studies have indicated that members of the System A transporter (SNAT2), the System N transporter (SNAT3), the Sy...

Small organelle, big responsibility: the role of centrosomes in development and disease

PubMed Central

Chavali, Pavithra L.; Pütz, Monika; Gergely, Fanni

2014-01-01

The centrosome, a key microtubule organizing centre, is composed of centrioles, embedded in a protein-rich matrix. Centrosomes control the internal spatial organization of somatic cells, and as such contribute to cell division, cell polarity and migration. Upon exiting the cell cycle, most cell types in the human body convert their centrioles into basal bodies, which drive the assembly of primary cilia, involved in sensing and signal transduction at the cell surface. Centrosomal genes are targeted by mutations in numerous human developmental disorders, ranging from diseases exclusively affecting brain development, through global growth failure syndromes to diverse pathologies associated with ciliary malfunction. Despite our much-improved understanding of centrosome function in cellular processes, we know remarkably little of its role in the organismal context, especially in mammals. In this review, we examine how centrosome dysfunction impacts on complex physiological processes and speculate on the challenges we face when applying knowledge generated from in vitro and in vivo model systems to human development. PMID:25047622

Cytoplasmic p21Cip1/WAF1 regulates neurite remodeling by inhibiting Rho-kinase activity

PubMed Central

Tanaka, Hiroyuki; Yamashita, Toshihide; Asada, Minoru; Mizutani, Shuki; Yoshikawa, Hideki; Tohyama, Masaya

2002-01-01

p21Cip1/WAF1 has cell cycle inhibitory activity by binding to and inhibiting both cyclin/Cdk kinases and proliferating cell nuclear antigen. Here we show that p21Cip1/WAF1 is induced in the cytoplasm during the course of differentiation of chick retinal precursor cells and N1E-115 cells. Ectopic expression of p21Cip1/WAF1 lacking the nuclear localization signal in N1E-115 cells and NIH3T3 cells affects the formation of actin structures, characteristic of inactivation of Rho. p21Cip1/WAF1 forms a complex with Rho-kinase and inhibits its activity in vitro and in vivo. Neurite outgrowth and branching from the hippocampal neurons are promoted if p21Cip1/WAF1 is expressed abundantly in the cytoplasm. These results suggest that cytoplasmic p21Cip1/WAF1 may contribute to the developmental process of the newborn neurons that extend axons and dendrites into target regions. PMID:12119358

Cytoplasmic p21(Cip1/WAF1) regulates neurite remodeling by inhibiting Rho-kinase activity.

PubMed

Tanaka, Hiroyuki; Yamashita, Toshihide; Asada, Minoru; Mizutani, Shuki; Yoshikawa, Hideki; Tohyama, Masaya

2002-07-22

p21(Cip1/WAF1) has cell cycle inhibitory activity by binding to and inhibiting both cyclin/Cdk kinases and proliferating cell nuclear antigen. Here we show that p21(Cip1/WAF1) is induced in the cytoplasm during the course of differentiation of chick retinal precursor cells and N1E-115 cells. Ectopic expression of p21(Cip1/WAF1) lacking the nuclear localization signal in N1E-115 cells and NIH3T3 cells affects the formation of actin structures, characteristic of inactivation of Rho. p21(Cip1/WAF1) forms a complex with Rho-kinase and inhibits its activity in vitro and in vivo. Neurite outgrowth and branching from the hippocampal neurons are promoted if p21(Cip1/WAF1) is expressed abundantly in the cytoplasm. These results suggest that cytoplasmic p21(Cip1/WAF1) may contribute to the developmental process of the newborn neurons that extend axons and dendrites into target regions.

Functional genomic characterization of neoblast-like stem cells in larval Schistosoma mansoni

PubMed Central

Wang, Bo; Collins, James J; Newmark, Phillip A

2013-01-01

Schistosomes infect hundreds of millions of people in the developing world. Transmission of these parasites relies on a stem cell-driven, clonal expansion of larvae inside a molluscan intermediate host. How this novel asexual reproductive strategy relates to current models of stem cell maintenance and germline specification is unclear. Here, we demonstrate that this proliferative larval cell population (germinal cells) shares some molecular signatures with stem cells from diverse organisms, in particular neoblasts of planarians (free-living relatives of schistosomes). We identify two distinct germinal cell lineages that differ in their proliferation kinetics and expression of a nanos ortholog. We show that a vasa/PL10 homolog is required for proliferation and maintenance of both populations, whereas argonaute2 and a fibroblast growth factor receptor-encoding gene are required only for nanos-negative cells. Our results suggest that an ancient stem cell-based developmental program may have enabled the evolution of the complex life cycle of parasitic flatworms. DOI: http://dx.doi.org/10.7554/eLife.00768.001 PMID:23908765

The effect of nonylphenol on gene expression in Atlantic salmon smolts

USGS Publications Warehouse

Robertson, Laura S.; McCormick, Stephen D.

2012-01-01

The parr–smolt transformation in Atlantic salmon (Salmo salar) is a complex developmental process that culminates in the ability to migrate to and live in seawater. Exposure to environmental contaminants like nonylphenol can disrupt smolt development and may be a contributing factor in salmon population declines. We used GRASP 16K cDNA microarrays to investigate the effects of nonylphenol on gene expression in Atlantic salmon smolts. Nonylphenol exposure reduced gill Na+/K+-ATPase activity and plasma cortisol and triiodothyronine levels. Transcriptional responses were examined in gill, liver, olfactory rosettes, hypothalamus, and pituitary. Expression of 124 features was significantly altered in the liver of fish exposed to nonylphenol; little to no transcriptional effects were observed in other tissues. mRNA abundance of genes involved in protein biosynthesis, folding, modification, transport and catabolism; nucleosome assembly, cell cycle, cell differentiation, microtubule-based movement, electron transport, and response to stress increased in nonylphenol-treated fish. This study expands our understanding of the effect of nonylphenol on smolting and provides potential targets for development of biomarkers.

Multiple Phosphatases Regulate Carbon Source-Dependent Germination and Primary Metabolism in Aspergillus nidulans

PubMed Central

de Assis, Leandro José; Ries, Laure Nicolas Annick; Savoldi, Marcela; Dinamarco, Taisa Magnani; Goldman, Gustavo Henrique; Brown, Neil Andrew

2015-01-01

Aspergillus nidulans is an important mold and a model system for the study of fungal cell biology. In addition, invasive A. nidulans pulmonary infections are common in humans with chronic granulomatous disease. The morphological and biochemical transition from dormant conidia into active, growing, filamentous hyphae requires the coordination of numerous biosynthetic, developmental, and metabolic processes. The present study exhibited the diversity of roles performed by seven phosphatases in regulating cell cycle, development, and metabolism in response to glucose and alternative carbon sources. The identified phosphatases highlighted the importance of several signaling pathways regulating filamentous growth, the action of the pyruvate dehydrogenase complex as a metabolic switch controlling carbon usage, and the identification of the key function performed by the α-ketoglutarate dehydrogenase during germination. These novel insights into the fundamental roles of numerous phosphatases in germination and carbon sensing have provided new avenues of research into the identification of inhibitors of fungal germination, with implications for the food, feed, and pharmaceutical industries. PMID:25762568

Identification of Marteilia refringens infecting the razor clam Solen marginatus by PCR and in situ hybridization.

PubMed

López-Flores, Inmaculada; Garrido-Ramos, Manuel A; de la Herran, Roberto; Ruiz-Rejón, Carmelo; Ruiz-Rejón, Manuel; Navas, José I

2008-06-01

Marteilia refringens is a protozoan parasite recognized as a significant pathogen of the European flat oyster Ostrea edulis. It is believed to have a complex life-cycle involving several hosts. In this study, we applied molecular approaches to identify this parasite in samples of the razor clam Solen marginatus from the south west coast of Spain. We used a PCR assay to amplify a fragment of the IGS rDNA region. PCR products were sequenced and the phylogenetic affinity of the sequences was determined. In situ hybridization analysis showed tissue distribution and presence of different developmental stages of the parasite in the digestive diverticula epithelium, which suggested a true parasitism in these individuals. This is the first report of the occurrence of M. refringens in the razor clam S. marginatus in the south Atlantic. The methodology described herein may be useful for accurate identification of the parasite strain in different hosts and thus provide valuable information for marteiliosis control programmes.

Genomic analysis of the causative agents of coccidiosis in domestic chickens

PubMed Central

Reid, Adam J.; Blake, Damer P.; Ansari, Hifzur R.; Billington, Karen; Browne, Hilary P.; Bryant, Josephine; Dunn, Matt; Hung, Stacy S.; Kawahara, Fumiya; Miranda-Saavedra, Diego; Malas, Tareq B.; Mourier, Tobias; Naghra, Hardeep; Nair, Mridul; Otto, Thomas D.; Rawlings, Neil D.; Rivailler, Pierre; Sanchez-Flores, Alejandro; Sanders, Mandy; Subramaniam, Chandra; Tay, Yea-Ling; Woo, Yong; Wu, Xikun; Barrell, Bart; Dear, Paul H.; Doerig, Christian; Gruber, Arthur; Ivens, Alasdair C.; Parkinson, John; Rajandream, Marie-Adèle; Shirley, Martin W.; Wan, Kiew-Lian; Berriman, Matthew

2014-01-01

Global production of chickens has trebled in the past two decades and they are now the most important source of dietary animal protein worldwide. Chickens are subject to many infectious diseases that reduce their performance and productivity. Coccidiosis, caused by apicomplexan protozoa of the genus Eimeria, is one of the most important poultry diseases. Understanding the biology of Eimeria parasites underpins development of new drugs and vaccines needed to improve global food security. We have produced annotated genome sequences of all seven species of Eimeria that infect domestic chickens, which reveal the full extent of previously described repeat-rich and repeat-poor regions and show that these parasites possess the most repeat-rich proteomes ever described. Furthermore, while no other apicomplexan has been found to possess retrotransposons, Eimeria is home to a family of chromoviruses. Analysis of Eimeria genes involved in basic biology and host-parasite interaction highlights adaptations to a relatively simple developmental life cycle and a complex array of co-expressed surface proteins involved in host cell binding. PMID:25015382

Rapid DNA replication origin licensing protects stem cell pluripotency

PubMed Central

Matson, Jacob Peter; Dumitru, Raluca; Coryell, Philip; Baxley, Ryan M; Chen, Weili; Twaroski, Kirk; Webber, Beau R; Tolar, Jakub; Bielinsky, Anja-Katrin; Purvis, Jeremy E

2017-01-01

Complete and robust human genome duplication requires loading minichromosome maintenance (MCM) helicase complexes at many DNA replication origins, an essential process termed origin licensing. Licensing is restricted to G1 phase of the cell cycle, but G1 length varies widely among cell types. Using quantitative single-cell analyses, we found that pluripotent stem cells with naturally short G1 phases load MCM much faster than their isogenic differentiated counterparts with long G1 phases. During the earliest stages of differentiation toward all lineages, MCM loading slows concurrently with G1 lengthening, revealing developmental control of MCM loading. In contrast, ectopic Cyclin E overproduction uncouples short G1 from fast MCM loading. Rapid licensing in stem cells is caused by accumulation of the MCM loading protein, Cdt1. Prematurely slowing MCM loading in pluripotent cells not only lengthens G1 but also accelerates differentiation. Thus, rapid origin licensing is an intrinsic characteristic of stem cells that contributes to pluripotency maintenance. PMID:29148972

SIGNALS AND REGULATORS THAT GOVERN STREPTOMYCES DEVELOPMENT

PubMed Central

McCormick, Joseph R.; Flärdh, Klas

2012-01-01

Streptomyces coelicolor is the genetically best characterized species of a populous genus belonging to the Gram-positive Actinobacteria. Streptomycetes are filamentous soil organisms, well known for the production of a plethora of biologically active secondary metabolic compounds. The Streptomyces developmental life cycle is uniquely complex, and involves coordinated multicellular development with both physiological and morphological differentiation of several cell types, culminating in production of secondary metabolites and dispersal of mature spores. This review presents a current appreciation of the signaling mechanisms used to orchestrate the decision to undergo morphological differentiation, and the regulators and regulatory networks that direct the intriguing development of multigenomic hyphae, first to form specialized aerial hyphae, and then to convert them into chains of dormant spores. This current view of S. coelicolor development is destined for rapid evolution as data from “-omics” studies shed light on gene regulatory networks, new genetic screens identify hitherto unknown players, and the resolution of our insights into the underlying cell biological processes steadily improve. PMID:22092088

Programming self-organizing multicellular structures with synthetic cell-cell signaling.

PubMed

Toda, Satoshi; Blauch, Lucas R; Tang, Sindy K Y; Morsut, Leonardo; Lim, Wendell A

2018-05-31

A common theme in the self-organization of multicellular tissues is the use of cell-cell signaling networks to induce morphological changes. We used the modular synNotch juxtacrine signaling platform to engineer artificial genetic programs in which specific cell-cell contacts induced changes in cadherin cell adhesion. Despite their simplicity, these minimal intercellular programs were sufficient to yield assemblies with hallmarks of natural developmental systems: robust self-organization into multi-domain structures, well-choreographed sequential assembly, cell type divergence, symmetry breaking, and the capacity for regeneration upon injury. The ability of these networks to drive complex structure formation illustrates the power of interlinking cell signaling with cell sorting: signal-induced spatial reorganization alters the local signals received by each cell, resulting in iterative cycles of cell fate branching. These results provide insights into the evolution of multi-cellularity and demonstrate the potential to engineer customized self-organizing tissues or materials. Copyright © 2018, American Association for the Advancement of Science.

The let-7 microRNA target gene, Mlin41/Trim71 is required for mouse embryonic survival and neural tube closure

PubMed Central

Schulman, Betsy R. Maller; Liang, Xianping; Stahlhut, Carlos; DelConte, Casey; Stefani, Giovanni; Slack, Frank J.

2010-01-01

In the nematode Caenorhabditis elegans, the let-7 microRNA (miRNA) controls the timing of key developmental events and terminal differentiation in part by directly regulating lin-41. C. elegans lin-41 mutants display precocious cell cycle exit and terminal differentiation of epidermal skin cells. lin-41 orthologues are found in more complex organisms including both mice and humans, but their roles are not known. We generated Mlin41 mouse mutants to ascertain a functional role for Mlin41. Strong loss of function Mlin41 gene-trap mutants demonstrated a striking neural tube closure defect during development, and embryonic lethality. Like C. elegans lin-41, Mlin41 also appears to be regulated by the let-7 and mir-125 miRNAs. Since Mlin41 is required for neural tube closure and survival it points to human lin-41 (HLIN41/TRIM71) as a potential human development and disease gene. PMID:19098426

HDAC2 deregulation in tumorigenesis is causally connected to repression of immune modulation and defense escape

PubMed Central

Conte, Mariarosaria; Dell'Aversana, Carmela; Benedetti, Rosaria; Petraglia, Francesca; Carissimo, Annamaria; Petrizzi, Valeria Belsito; D'Arco, Alfonso Maria; Abbondanza, Ciro; Nebbioso, Angela; Altucci, Lucia

2015-01-01

Histone deacetylase 2 (HDAC2) is overexpressed or mutated in several disorders such as hematological cancers, and plays a critical role in transcriptional regulation, cell cycle progression and developmental processes. Here, we performed comparative transcriptome analyses in acute myeloid leukemia to investigate the biological implications of HDAC2 silencing versus its enzymatic inhibition using epigenetic-based drug(s). By gene expression analysis of HDAC2-silenced vs wild-type cells, we found that HDAC2 has a specific role in leukemogenesis. Gene expression profiling of U937 cell line with or without treatment of the well-known HDAC inhibitor vorinostat (SAHA) identifies and characterizes several gene clusters where inhibition of HDAC2 ‘mimics’ its silencing, as well as those where HDAC2 is selectively and exclusively regulated by HDAC2 protein expression levels. These findings may represent an important tool for better understanding the mechanisms underpinning immune regulation, particularly in the study of major histocompatibility complex class II genes. PMID:25473896

20170312 - Computer Simulation of Developmental ...

EPA Pesticide Factsheets

Rationale: Recent progress in systems toxicology and synthetic biology have paved the way to new thinking about in vitro/in silico modeling of developmental processes and toxicities, both for embryological and reproductive impacts. Novel in vitro platforms such as 3D organotypic culture models, engineered microscale tissues and complex microphysiological systems (MPS), together with computational models and computer simulation of tissue dynamics, lend themselves to a integrated testing strategies for predictive toxicology. As these emergent methodologies continue to evolve, they must be integrally tied to maternal/fetal physiology and toxicity of the developing individual across early lifestage transitions, from fertilization to birth, through puberty and beyond. Scope: This symposium will focus on how the novel technology platforms can help now and in the future, with in vitro/in silico modeling of complex biological systems for developmental and reproductive toxicity issues, and translating systems models into integrative testing strategies. The symposium is based on three main organizing principles: (1) that novel in vitro platforms with human cells configured in nascent tissue architectures with a native microphysiological environments yield mechanistic understanding of developmental and reproductive impacts of drug/chemical exposures; (2) that novel in silico platforms with high-throughput screening (HTS) data, biologically-inspired computational models of

Computer Simulation of Developmental Processes and ...

EPA Pesticide Factsheets

Rationale: Recent progress in systems toxicology and synthetic biology have paved the way to new thinking about in vitro/in silico modeling of developmental processes and toxicities, both for embryological and reproductive impacts. Novel in vitro platforms such as 3D organotypic culture models, engineered microscale tissues and complex microphysiological systems (MPS), together with computational models and computer simulation of tissue dynamics, lend themselves to a integrated testing strategies for predictive toxicology. As these emergent methodologies continue to evolve, they must be integrally tied to maternal/fetal physiology and toxicity of the developing individual across early lifestage transitions, from fertilization to birth, through puberty and beyond. Scope: This symposium will focus on how the novel technology platforms can help now and in the future, with in vitro/in silico modeling of complex biological systems for developmental and reproductive toxicity issues, and translating systems models into integrative testing strategies. The symposium is based on three main organizing principles: (1) that novel in vitro platforms with human cells configured in nascent tissue architectures with a native microphysiological environments yield mechanistic understanding of developmental and reproductive impacts of drug/chemical exposures; (2) that novel in silico platforms with high-throughput screening (HTS) data, biologically-inspired computational models of

Trust-Based Relational Intervention (TBRI): A Systemic Approach to Complex Developmental Trauma

PubMed Central

Purvis, Karyn B.; Cross, David R.; Dansereau, Donald F.; Parris, Sheri R.

2013-01-01

Children and youth who have experienced foster care or orphanage-rearing have often experienced complex developmental trauma, demonstrating an interactive set of psychological and behavioral issues. Trust-Based Relational Intervention (TBRI) is a therapeutic model that trains caregivers to provide effective support and treatment for at-risk children. TBRI has been applied in orphanages, courts, residential treatment facilities, group homes, foster and adoptive homes, churches, and schools. It has been used effectively with children and youth of all ages and all risk levels. This article provides the research base for TBRI and examples of how it is applied. PMID:24453385

Characterization of a complex chromosomal rearrangement using chromosome, FISH, and microarray assays in a girl with multiple congenital abnormalities and developmental delay

PubMed Central

2014-01-01

Complex chromosomal rearrangements (CCRs) are balanced or unbalanced structural rearrangements involving three or more cytogenetic breakpoints on two or more chromosomal pairs. The phenotypic anomalies in such cases are attributed to gene disruption, superimposed cryptic imbalances in the genome, and/or position effects. We report a 14-year-old girl who presented with multiple congenital anomalies and developmental delay. Chromosome and FISH analysis indicated a highly complex chromosomal rearrangement involving three chromosomes (3, 7 and 12), seven breakpoints as a result of one inversion, two insertions, and two translocations forming three derivative chromosomes. Additionally, chromosomal microarray study (CMA) revealed two submicroscopic deletions at 3p12.3 (467 kb) and 12q13.12 (442 kb). We postulate that microdeletion within the ROBO1 gene at 3p12.3 may have played a role in the patient’s developmental delay, since it has potential activity-dependent role in neurons. Additionally, factors other than genomic deletions such as loss of function or position effects may also contribute to the abnormal phenotype in our patient. PMID:25478007

Environmental perception and epigenetic memory: mechanistic insight through FLC

PubMed Central

Berry, Scott; Dean, Caroline

2015-01-01

Chromatin plays a central role in orchestrating gene regulation at the transcriptional level. However, our understanding of how chromatin states are altered in response to environmental and developmental cues, and then maintained epigenetically over many cell divisions, remains poor. The floral repressor gene FLOWERING LOCUS C (FLC) in Arabidopsis thaliana is a useful system to address these questions. FLC is transcriptionally repressed during exposure to cold temperatures, allowing studies of how environmental conditions alter expression states at the chromatin level. FLC repression is also epigenetically maintained during subsequent development in warm conditions, so that exposure to cold may be remembered. This memory depends on molecular complexes that are highly conserved among eukaryotes, making FLC not only interesting as a paradigm for understanding biological decision-making in plants, but also an important system for elucidating chromatin-based gene regulation more generally. In this review, we summarize our understanding of how cold temperature induces a switch in the FLC chromatin state, and how this state is epigenetically remembered. We also discuss how the epigenetic state of FLC is reprogrammed in the seed to ensure a requirement for cold exposure in the next generation. Significance Statement FLOWERING LOCUS C (FLC) regulation provides a paradigm for understanding how chromatin can be modulated to determine gene expression in a developmental context. This review describes our current mechanistic understanding of how FLC expression is genetically specified and epigenetically regulated throughout the plant life cycle, and how this determines plant life-history strategy. PMID:25929799

[What makes an insect a vector?].

PubMed

Kampen, Helge

2009-01-01

Blood-feeding insects transmit numerous viruses, bacteria, protozoans and helminths to vertebrates. The developmental cycles of the microorganisms in their vectors and the mechanisms of transmission are generally extremely complex and the result of a long-lasting coevolution of vector and vectored pathogen based on mutual adaptation. The conditions necessary for an insect to become a vector are multiple but require an innate vector competence as a genetic basis. Next to the vector competence plenty of entomological, ecological and pathogen-related factors are decisive, given the availability of infection sources. The various modes of pathogen transmission by vectors are connected to the developmental routes of the microorganisms in their vectors. In particular, pathogens transmitted by saliva encounter a lot of cellular and acellular barriers during their migration from the insect's midgut through the hemocele into the salivary fluid, including components of the insect's immune system. With regard to intracellular development, receptor-mediated invasion mechanisms are of relevance. As an environmental factor, the temperature has a paramount impact on the vectorial roles of hematophagous insects. Not only has it a considerable influence on the duration of a pathogen's development in its vector (extrinsic incubation period) but it can render putatively vector-incompetent insects to vectors ("leaky gut" phenomenon). Equally crucial are behavioural aspects of both the insect and the pathogen such as blood host preferences, seasonal appearance and circadian biting activity on the vector's side and diurnal/nocturnal periodicity on the pathogen's side which facilitate a contact in the first place.

Testing strategies for embryo-fetal toxicity of human pharmaceuticals. Animal models vs. in vitro approaches: a workshop report.

PubMed

van der Laan, Jan Willem; Chapin, Robert E; Haenen, Bert; Jacobs, Abigail C; Piersma, Aldert

2012-06-01

Reproductive toxicity testing is characterized by high animal use. For registration of pharmaceutical compounds, developmental toxicity studies are usually conducted in both rat and rabbits. Efforts have been underway for a long time to design alternatives to animal use. Implementation has lagged, partly because of uncertainties about the applicability domain of the alternatives. The reproductive cycle is complex and not all mechanisms of development can be mimicked in vitro. Therefore, efforts are underway to characterize the available alternative tests with regard to the mechanism of action they include. One alternative test is the mouse embryonic stem cell test (EST), which has been studied since the late 1990s. It is a genuine 3R "alternative" assay as it is essentially animal-free. A meeting was held to review the state-of-the-art of various in vitro models for prediction of developmental toxicity. Although the predictivity of individual assays is improving, a battery of several assays is likely to have even higher predictivity, which is necessary for regulatory acceptance. The workshop concluded that an important first step is a thorough survey of the existing rat and rabbit studies, to fully characterize the frequency of responses and the types of effects seen. At the same time, it is important to continue the optimization of in vitro assays. As more experience accumulates, the optimal conditions, assay structure, and applicability of the alternative assays are expected to emerge. Copyright © 2012 Elsevier Inc. All rights reserved.

A maize root tip system to study DNA replication programmes in somatic and endocycling nuclei during plant development.

PubMed

Bass, Hank W; Wear, Emily E; Lee, Tae-Jin; Hoffman, Gregg G; Gumber, Hardeep K; Allen, George C; Thompson, William F; Hanley-Bowdoin, Linda

2014-06-01

The progress of nuclear DNA replication is complex in both time and space, and may reflect several levels of chromatin structure and 3-dimensional organization within the nucleus. To understand the relationship between DNA replication and developmental programmes, it is important to examine replication and nuclear substructure in different developmental contexts including natural cell-cycle progressions in situ. Plant meristems offer an ideal opportunity to analyse such processes in the context of normal growth of an organism. Our current understanding of large-scale chromosomal DNA replication has been limited by the lack of appropriate tools to visualize DNA replication with high resolution at defined points within S phase. In this perspective, we discuss a promising new system that can be used to visualize DNA replication in isolated maize (Zea mays L.) root tip nuclei after in planta pulse labelling with the thymidine analogue, 5-ethynyl-2'-deoxyuridine (EdU). Mixed populations of EdU-labelled nuclei are then separated by flow cytometry into sequential stages of S phase and examined directly using 3-dimensional deconvolution microscopy to characterize spatial patterns of plant DNA replication. Combining spatiotemporal analyses with studies of replication and epigenetic inheritance at the molecular level enables an integrated experimental approach to problems of mitotic inheritance and cellular differentiation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Module Based Complexity Formation: Periodic Patterning in Feathers and Hairs

PubMed Central

Chuong, Cheng-Ming; Yeh, Chao-Yuan; Jiang, Ting-Xin; Widelitz, Randall

2012-01-01

Patterns describe order which emerges from homogeneity. Complex patterns on the integument are striking because of their visibility throughout an organism's lifespan. Periodic patterning is an effective design because the ensemble of hair or feather follicles (modules) allows the generation of complexity, including regional variations and cyclic regeneration, giving the skin appendages a new lease on life. Spatial patterns include the arrangements of feathers and hairs in specified number, size, and spacing. We explore how a field of equivalent progenitor cells can generate periodically arranged modules based on genetic information, physical-chemical rules and developmental timing. Reconstitution experiments suggest a competitive equilibrium regulated by activators / inhibitors involving Turing reaction-diffusion. Temporal patterns result from oscillating stem cell activities within each module (micro-environment regulation), reflected as growth (anagen) and resting (telogen) phases during the cycling of feather and hair follicles. Stimulating modules with activators initiates the spread of regenerative hair waves, while global inhibitors outside each module (macro-environment) prevent this. Different wave patterns can be simulated by Cellular Automata principles. Hormonal status and seasonal changes can modulate appendage phenotypes, leading to “organ metamorphosis”, with multiple ectodermal organ phenotypes generated from the same precursors. We discuss potential evolutionary novel steps using this module based complexity in several amniote integument organs, exemplified by the spectacular peacock feather pattern. We thus explore the application of the acquired knowledge of patterning in tissue engineering. New hair follicles can be generated after wounding. Hairs and feathers can be reconstituted through self-organization of dissociated progenitor cells. PMID:23539312

Module-based complexity formation: periodic patterning in feathers and hairs.

PubMed

Chuong, Cheng-Ming; Yeh, Chao-Yuan; Jiang, Ting-Xin; Widelitz, Randall

2013-01-01

Patterns describe order which emerges from homogeneity. Complex patterns on the integument are striking because of their visibility throughout an organism’s lifespan. Periodic patterning is an effective design because the ensemble of hair or feather follicles (modules) allows the generation of complexity, including regional variations and cyclic regeneration, giving the skin appendages a new lease on life. Spatial patterns include the arrangements of feathers and hairs in specific number, size, and spacing.We explorehowa field of equivalent progenitor cells can generate periodically arranged modules based on genetic information, physical–chemical rules and developmental timing. Reconstitution experiments suggest a competitive equilibrium regulated by activators/inhibitors involving Turing reaction-diffusion. Temporal patterns result from oscillating stem cell activities within each module (microenvironment regulation), reflected as growth (anagen) and resting (telogen) phases during the cycling of feather and hair follicles. Stimulating modules with activators initiates the spread of regenerative hair waves, while global inhibitors outside each module (macroenvironment) prevent this. Different wave patterns can be simulated by cellular automata principles. Hormonal status and seasonal changes can modulate appendage phenotypes, leading to ‘organ metamorphosis’, with multiple ectodermal organ phenotypes generated from the same precursors. We discuss potential novel evolutionary steps using this module-based complexity in several amniote integument organs, exemplified by the spectacular peacock feather pattern. We thus explore the application of the acquired knowledge of patterning in tissue engineering. New hair follicles can be generated after wounding. Hairs and feathers can be reconstituted through self-organization of dissociated progenitor cells. © 2012 Wiley Periodicals, Inc.

Life cycle of a plant parasitic mite, Tetranychus sayedi Baker & Pitchard (Acari: Tetranychidae) on two hosts from West Bengal, India.

PubMed

Mondal, Sagata; Gupta, Salil Kumar

2017-09-01

The present paper reports duration of different developmental stages as well as fecundity, longevity, oviposition periods, sex ratio, etc. of Tetranychus sayedi Baker & Pitchard on two medicinal plants, viz. Cryptolepis buchanani Roem & Schult and Justicia adhatoda L. under laboratory condition at 27.5 °C and 65% R.H. during February-March, 2016. The two hosts in which the life cycle was studied form two new records of hosts for this mite. It appears that C. buchanani is better host among the two hosts as because the life cycle (egg to adult) was completed in shorter time, recording high fecundity and longer longevity.

Social Inequality in Population Developmental Health: An Equity and Justice Issue.

PubMed

Keating, Daniel P

2016-01-01

The conceptual framework for this chapter focuses on outcomes in developmental health as a key indicator of equity. Not all disparities in developmental health are indicators of a failure of equity and justice, but those that are clearly linked to social patterns in theoretically coherent and empirically substantial ways serve as a powerful diagnostic tool. They are especially diagnostic when they point to social factors that are remediable, especially in comparison to societies in which such social disparities are sharply lower (Keating, Siddiqi, & Nguyen, 2013). In this chapter, I review the theoretical links and empirical evidence supporting this central claim and propose that there is strong evidence for the following critical links: (a) there is a compelling empirical connection between disparities in social circumstances and disparities in developmental health outcomes, characterized as a social gradient effect; (b) "drilling down" reveals the core biodevelopmental mechanisms that yield the social disparities that emerge across the life course; (c) in turn, life course effects on developmental health have an impact on societies and populations that are revealed by "ramping up" the research to consider international comparisons of population developmental health; and (d) viewing this integrated evidence through the lens of equity and justice helps to break the vicious cycle that reproduces social inequality in a distressingly recurring fashion. © 2016 Elsevier Inc. All rights reserved.

Systematic developmental neurotoxicity assessment of a representative PAH Superfund mixture using zebrafish.

PubMed

Geier, Mitra C; James Minick, D; Truong, Lisa; Tilton, Susan; Pande, Paritosh; Anderson, Kim A; Teeguardan, Justin; Tanguay, Robert L

2018-04-06

Superfund sites often consist of complex mixtures of polycyclic aromatic hydrocarbons (PAHs). It is widely recognized that PAHs pose risks to human and environmental health, but the risks posed by exposure to PAH mixtures are unclear. We constructed an environmentally relevant PAH mixture with the top 10 most prevalent PAHs (SM10) from a Superfund site derived from environmental passive sampling data. Using the zebrafish model, we measured body burden at 48 hours post fertilization (hpf) and evaluated the developmental and neurotoxicity of SM10 and the 10 individual constituents at 24 hours post fertilization (hpf) and 5 days post fertilization (dpf). Zebrafish embryos were exposed from 6 to 120 hpf to (1) the SM10 mixture, (2) a variety of individual PAHs: pyrene, fluoranthene, retene, benzo[a]anthracene, chrysene, naphthalene, acenaphthene, phenanthrene, fluorene, and 2-methylnaphthalene. We demonstrated that SM10 and only 3 of the individual PAHs were developmentally toxic. Subsequently, we constructed and exposed developing zebrafish to two sub-mixtures: SM3 (comprised of 3 of the developmentally toxicity PAHs) and SM7 (7 non-developmentally toxic PAHs). We found that the SM3 toxicity profile was similar to SM10, and SM7 unexpectedly elicited developmental toxicity unlike that seen with its individual components. The results demonstrated that the overall developmental toxicity in the mixtures could be explained using the general concentration addition model. To determine if exposures activated the AHR pathway, spatial expression of CYP1A was evaluated in the 10 individual PAHs and the 3 mixtures at 5 dpf. Results showed activation of AHR in the liver and vasculature for the mixtures and some individual PAHs. Embryos exposed to SM10 during development and raised in chemical-free water into adulthood exhibited decreased learning and responses to startle stimulus indicating that developmental SM10 exposures affect neurobehavior. Collectively, these results exemplify the utility of zebrafish to investigate the developmental and neurotoxicity of complex mixtures. Copyright © 2018 Elsevier Inc. All rights reserved.

Adult Development and the Workplace.

ERIC Educational Resources Information Center

Heffernan, James M.

Little attention has been given to how adults develop through their lifetimes and what roles their workplace environments play in that development. Research and theory regarding adult psychosocial development have confirmed the developmental life-cycle phases of adulthood. These are: leaving the family (ages 16-22), getting into the adult world…

Rapid Prototyping Methodology in Action: A Developmental Study.

ERIC Educational Resources Information Center

Jones, Toni Stokes; Richey, Rita C.

2000-01-01

Investigated the use of rapid prototyping methodologies in two projects conducted in a natural work setting to determine the nature of its use by designers and customers and the extent to which its use enhances traditional instructional design. Discusses design and development cycle-time reduction, product quality, and customer and designer…

Characterization of gut bacteria at different developmental stages of Asian honey bees, Apis cerana

USDA-ARS?s Scientific Manuscript database

Previous surveys have shown that adult workers of the Asian honey bee Apis cerana harbor four major gut microbes (Bifidobacterium, Snodgrassella alvi, Gilliamella apicola, and Lactobacillus). Using quantitative PCR we characterized gut bacterial communities across the life cycle of A. cerana from la...

Family Life Satisfaction across Positional Roles, Family Development Categories and SES.

ERIC Educational Resources Information Center

Tiffany, Phyllis G.

Marital satisfaction across the life cycle differs for men and women. To investigate family life satisfaction across positional roles, developmental categories, and socioeconomic status (SES), 100 husbands and wives (families) were administered the Heimler Schedule of Social Functioning (SOSF), which relates social function and stressors (work,…

75 FR 28810 - National Institute of General Medical Sciences; Notice of Closed Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-24

... funding cycle. (Catalogue of Federal Domestic Assistance Program Nos. 93.375, Minority Biomedical Research Support; 93.821, Cell Biology and Biophysics Research; 93.859, Pharmacology, Physiology, and Biological Chemistry Research; 93.862, Genetics and Developmental Biology Research; 93.88, Minority Access to Research...

DEVELOPMENTAL STAGE-SPECIFIC LIFE-CYCLE BIOASSAY FOR ASSESSMENT OF SEDIMENT-ASSOCIATED TOXICANT EFFECTS ON BENTHIC COPEPOD PRODUCTION. (R827397)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Patterns of gender development.

PubMed

Martin, Carol Lynn; Ruble, Diane N

2010-01-01

A comprehensive theory of gender development must describe and explain long-term developmental patterning and changes and how gender is experienced in the short term. This review considers multiple views on gender patterning, illustrated with contemporary research. First, because developmental research involves understanding normative patterns of change with age, several theoretically important topics illustrate gender development: how children come to recognize gender distinctions and understand stereotypes, and the emergence of prejudice and sexism. Second, developmental researchers study the stability of individual differences over time, which elucidates developmental processes. We review stability in two domains-sex segregation and activities/interests. Finally, a new approach advances understanding of developmental patterns, based on dynamic systems theory. Dynamic systems theory is a metatheoretical framework for studying stability and change, which developed from the study of complex and nonlinear systems in physics and mathematics. Some major features and examples show how dynamic approaches have been and could be applied in studying gender development.

Patterns of Gender Development

PubMed Central

Martin, Carol Lynn; Ruble, Diane N.

2013-01-01

A comprehensive theory of gender development must describe and explain long-term developmental patterning and changes and how gender is experienced in the short term. This review considers multiple views on gender patterning, illustrated with contemporary research. First, because developmental research involves understanding normative patterns of change with age, several theoretically important topics illustrate gender development: how children come to recognize gender distinctions and understand stereotypes, and the emergence of prejudice and sexism. Second, developmental researchers study the stability of individual differences over time, which elucidates developmental processes. We review stability in two domains—sex segregation and activities/interests. Finally, a new approach advances understanding of developmental patterns, based on dynamic systems theory. Dynamic systems theory is a metatheoretical framework for studying stability and change, which developed from the study of complex and nonlinear systems in physics and mathematics. Some major features and examples show how dynamic approaches have been and could be applied in studying gender development. PMID:19575615

The chemistry of caries: remineralization and demineralization events with direct clinical relevance.

PubMed

González-Cabezas, Carlos

2010-07-01

Dental caries is a site-specific disease that undergoes many cycles of demineralization and remineralization during lesion development. Because of its developmental characteristics dynamics, the caries lesion can be arrested and even repaired at its early stages without operative intervention by increasing the net mineral gain during the demineralization and remineralization cycles. This result can be accomplished by reducing the effect of etiological factors such as cariogenic biofilms and diet, and increasing the efficacy of remineralizing agents such as saliva and fluoride. Copyright 2010 Elsevier Inc. All rights reserved.

The evaluation life cycle: a retrospective assessment of stages and phases of the circles of care initiative.

PubMed

Bess, Gary; Allen, James; Deters, Pamela B

2004-08-12

A life cycle metaphor characterizes the evolving relationship between the evaluator and program staff. This framework suggests that common developmental dynamics occur in roughly the same order across groups and settings. There are stage-specific dynamics that begin with Pre-History, which characterize the relationship between the grantees and evaluator. The stages are: (a) Pre-History, (b) Process, (c) Development, (d) Action, (e) Findings-Compilation, and (f) Transition. The common dynamics, expectations, and activities for each stage are discussed.

The Bio-Logic and machinery of plant morphogenesis.

PubMed

Niklas, Karl J

2003-04-01

Morphogenesis (the development of organic form) requires signal-trafficking and cross-talking across all levels of organization to coordinate the operation of metabolic and genomic networked systems. Many biologists are currently converging on the pictorial conventions of computer scientists to render biological signaling as logic circuits supervising the operation of one or more signal-activated metabolic or gene networks. This approach can redact and simplify complex morphogenetic phenomena and allows for their aggregation into diagrams of larger, more "global" networked systems. This conceptualization is discussed in terms of how logic circuits and signal-activated subsystems work, and it is illustrated for examples of increasingly more complex morphogenetic phenomena, e.g., auxin-mediated cell expansion, entry into the mitotic cell cycle phases, and polar/lateral intercellular auxin transport. For each of these phenomena, a posited circuit/subsystem diagram draws rapid attention to missing components, either in the logic circuit or in the subsystem it supervises. These components must be identified experimentally if each of these basic phenomena is to be fully understood. Importantly, the power of the circuit/subsystem approach to modeling developmental phenomena resides not in its pictorial appeal but in the mathematical tools that are sufficiently strong to reveal and quantify the synergistics of networked systems and thus foster a better understanding of morphogenesis.

Environmental factors, epigenetics, and developmental origin of reproductive disorders.

PubMed

Ho, Shuk-Mei; Cheong, Ana; Adgent, Margaret A; Veevers, Jennifer; Suen, Alisa A; Tam, Neville N C; Leung, Yuet-Kin; Jefferson, Wendy N; Williams, Carmen J

2017-03-01

Sex-specific differentiation, development, and function of the reproductive system are largely dependent on steroid hormones. For this reason, developmental exposure to estrogenic and anti-androgenic endocrine disrupting chemicals (EDCs) is associated with reproductive dysfunction in adulthood. Human data in support of "Developmental Origins of Health and Disease" (DOHaD) comes from multigenerational studies on offspring of diethylstilbestrol-exposed mothers/grandmothers. Animal data indicate that ovarian reserve, female cycling, adult uterine abnormalities, sperm quality, prostate disease, and mating behavior are susceptible to DOHaD effects induced by EDCs such as bisphenol A, genistein, diethylstilbestrol, p,p'-dichlorodiphenyl-dichloroethylene, phthalates, and polyaromatic hydrocarbons. Mechanisms underlying these EDC effects include direct mimicry of sex steroids or morphogens and interference with epigenomic sculpting during cell and tissue differentiation. Exposure to EDCs is associated with abnormal DNA methylation and other epigenetic modifications, as well as altered expression of genes important for development and function of reproductive tissues. Here we review the literature exploring the connections between developmental exposure to EDCs and adult reproductive dysfunction, and the mechanisms underlying these effects. Copyright © 2016 Elsevier Inc. All rights reserved.

Environmental Factors, Epigenetics, and Developmental Origin of Reproductive Disorders

PubMed Central

Ho, Shuk-Mei; Cheong, Ana; Adgent, Margaret A.; Veevers, Jennifer; Suen, Alisa A.; Tam, Neville N.C.; Leung, Yuet-Kin; Jefferson, Wendy N.; Williams, Carmen J.

2016-01-01

Sex-specific differentiation, development, and function of the reproductive system are largely dependent on steroid hormones. For this reason, developmental exposure to estrogenic and anti-androgenic endocrine disrupting chemicals (EDCs) is associated with reproductive dysfunction in adulthood. Human data in support of “Developmental Origins of Health and Disease” (DOHaD) comes from multigenerational studies on offspring of diethylstilbestrol-exposed mothers/grandmothers. Animal data indicate that ovarian reserve, female cycling, adult uterine abnormalities, sperm quality, prostate disease, and mating behavior are susceptible to DOHaD effects induced by EDCs such as bisphenol A, genistein, diethylstilbestrol, p,p′-dichlorodiphenyl-dichloroethylene, phthalates, and polyaromatic hydrocarbons. Mechanisms underlying these EDC effects include direct mimicry of sex steroids or morphogens and interference with epigenomic sculpting during cell and tissue differentiation. Exposure to EDCs is associated with abnormal DNA methylation and other epigenetic modifications, as well as altered expression of genes important for development and function of reproductive tissues. Here we review the literature exploring the connections between developmental exposure to EDCs and adult reproductive dysfunction, and the mechanisms underlying these effects. PMID:27421580

Managing Complexity: Impact of Organization and Processing Style on Nonverbal Memory in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Tsatsanis, Katherine D.; Noens, Ilse L. J.; Illmann, Cornelia L.; Pauls, David L.; Volkmar, Fred R.; Schultz, Robert T.; Klin, Ami

2011-01-01

The contributions of cognitive style and organization to processing and recalling a complex novel stimulus were examined by comparing the Rey Osterrieth Complex Figure (ROCF) test performance of children, adolescents, and adults with ASD to clinical controls (CC) and non-impaired controls (NC) using the "Developmental Scoring System."…

Diapause hormone in the Helicoverpa/Heliothis complex: a review of gene expression, peptide structure and activity, analog and antagonist development, and the receptor

USDA-ARS?s Scientific Manuscript database

This review summarizes recent studies focusing on diapause hormone (DH) in the Helicoverpa/Heliothis complex of agricultural pests. Moths in this complex overwinter in pupal diapause, a form of developmental arrest used to circumvent unfavorable seasons. DH was originally reported in the silkmoth ...

Generalized additive models and Lucilia sericata growth: assessing confidence intervals and error rates in forensic entomology.

PubMed

Tarone, Aaron M; Foran, David R

2008-07-01

Forensic entomologists use blow fly development to estimate a postmortem interval. Although accurate, fly age estimates can be imprecise for older developmental stages and no standard means of assigning confidence intervals exists. Presented here is a method for modeling growth of the forensically important blow fly Lucilia sericata, using generalized additive models (GAMs). Eighteen GAMs were created to predict the extent of juvenile fly development, encompassing developmental stage, length, weight, strain, and temperature data, collected from 2559 individuals. All measures were informative, explaining up to 92.6% of the deviance in the data, though strain and temperature exerted negligible influences. Predictions made with an independent data set allowed for a subsequent examination of error. Estimates using length and developmental stage were within 5% of true development percent during the feeding portion of the larval life cycle, while predictions for postfeeding third instars were less precise, but within expected error.

How do environmental factors influence life cycles and development? An experimental framework for early-diverging metazoans

PubMed Central

Bosch, Thomas C. G.; Adamska, Maja; Augustin, René; Domazet-Loso, Tomislav; Foret, Sylvain; Fraune, Sebastian; Funayama, Noriko; Grasis, Juris; Hamada, Mayuko; Hatta, Masayuki; Hobmayer, Bert; Kawai, Kotoe; Klimovich, Alexander; Manuel, Michael; Shinzato, Chuya; Technau, Uli; Yum, Seungshic; Miller, David J.

2014-01-01

Ecological developmental biology (eco-devo) explores the mechanistic relationships between the processes of individual development and environmental factors. Recent studies imply that some of these relationships have deep evolutionary origins, and may even predate the divergences of the simplest extant animals, including cnidarians and sponges. Development of these early diverging metazoans is often sensitive to environmental factors, and these interactions occur in the context of conserved signaling pathways and mechanisms of tissue homeostasis whose detailed molecular logic remain elusive. Efficient methods for transgenesis in cnidarians together with the ease of experimental manipulation in cnidarians and sponges make them ideal models for understanding causal relationships between environmental factors and developmental mechanisms. Here, we identify major questions at the interface between animal evolution and development and outline a road map for research aimed at identifying the mechanisms that link environmental factors to developmental mechanisms in early diverging metazoans. PMID:25205353

Developmental stages of Trypanosoma (Megatrypanum) freitasi Rego, Magalhães & Siqueira, 1957 in the opossum Didelphis marsupialis (Marsupialia, Didelphidae).

PubMed

Deane, M P; Jansen, A M

1990-01-01

Trypanosoma (Megatrypanum) freitasi, a parasite of marsupials of the genus Didelphis, has been found to undergo in the lumen of the scent (anal) glands of its vertebrate host, a cycle such as usually occurs in the intestinal tract of the insect vectors of trypanosomatids and similar to what has been reported for Trypanosoma (Schizotrypanum) cruzi. The invertebrate host of Trypanosoma freitasi is still unknown. Developmental stages of the trypanosome in its mammalian host, especially the dividing epimastigotes, multinucleate plasmodial forms and rosettes found in the lumen of the scent glands of a naturally infected Didelphis marsupialis are described and illustrated.

Precursors to language development in typically and atypically developing infants and toddlers: the importance of embracing complexity.

PubMed

D'Souza, Dean; D'Souza, Hana; Karmiloff-Smith, Annette

2017-05-01

In order to understand how language abilities emerge in typically and atypically developing infants and toddlers, it is important to embrace complexity in development. In this paper, we describe evidence that early language development is an experience-dependent process, shaped by diverse, interconnected, interdependent developmental mechanisms, processes, and abilities (e.g. statistical learning, sampling, functional specialization, visual attention, social interaction, motor ability). We also present evidence from our studies on neurodevelopmental disorders (e.g. Down syndrome, fragile X syndrome, Williams syndrome) that variations in these factors significantly contribute to language delay. Finally, we discuss how embracing complexity, which involves integrating data from different domains and levels of description across developmental time, may lead to a better understanding of language development and, critically, lead to more effective interventions for cases when language develops atypically.

Impaired activity of CCA-adding enzyme TRNT1 impacts OXPHOS complexes and cellular respiration in SIFD patient-derived fibroblasts.

PubMed

Liwak-Muir, Urszula; Mamady, Hapsatou; Naas, Turaya; Wylie, Quinlan; McBride, Skye; Lines, Matthew; Michaud, Jean; Baird, Stephen D; Chakraborty, Pranesh K; Holcik, Martin

2016-06-18

SIFD (Sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay) is a novel form of congenital sideroblastic anemia associated with B-cell immunodeficiency, periodic fevers, and developmental delay caused by mutations in the CCA-adding enzyme TRNT1, but the precise molecular pathophysiology is not known. We show that the disease causing mutations in patient-derived fibroblasts do not affect subcellular localization of TRNT1 and show no gross morphological differences when compared to control cells. Analysis of cellular respiration and oxidative phosphorylation (OXPHOS) complexes demonstrates that both basal and maximal respiration rates are decreased in patient cells, which may be attributed to an observed decrease in the abundance of select proteins of the OXPHOS complexes. Our data provides further insight into cellular pathophysiology of SIFD.

Simple Mindreading Abilities Predict Complex Theory of Mind: Developmental Delay in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Pino, Maria Chiara; Mazza, Monica; Mariano, Melania; Peretti, Sara; Dimitriou, Dagmara; Masedu, Francesco; Valenti, Marco; Franco, Fabia

2017-01-01

Theory of mind (ToM) is impaired in individuals with autism spectrum disorders (ASD). The aims of this study were to: (i) examine the developmental trajectories of ToM abilities in two different mentalizing tasks in children with ASD compared to TD children; and (ii) to assess if a ToM simple test known as eyes-test could predict performance on…

Prevalence of Autism Spectrum Disorders: Autism and Developmental Disabilities Monitoring Network, 14 Sites, United States, 2008. Morbidity and Mortality Weekly Report. Surveillance Summaries. Volume 61, Number 3

ERIC Educational Resources Information Center

Baio, Jon

2012-01-01

Problem/Condition: Autism spectrum disorders (ASDs) are a group of developmental disabilities characterized by impairments in social interaction and communication and by restricted, repetitive, and stereotyped patterns of behavior. Symptoms typically are apparent before age 3 years. The complex nature of these disorders, coupled with a lack of…

Carryover Effects of Acute DEHP Exposure on Ovarian Function and Oocyte Developmental Competence in Lactating Cows

PubMed Central

Kalo, Dorit; Hadas, Ron; Furman, Ori; Ben-Ari, Julius; Maor, Yehoshua; Patterson, Donald G.; Tomey, Cynthia; Roth, Zvi

2015-01-01

We examined acute exposure of Holstein cows to di(2-ethylhexyl) phthalate (DEHP) and its carryover effects on ovarian function and oocyte developmental competence. Synchronized cows were tube-fed with water or 100 mg/kg DEHP per day for 3 days. Blood, urine and milk samples were collected before, during and after DEHP exposure to examine its clearance pattern. Ovarian follicular dynamics was monitored through an entire estrous cycle by ultrasonographic scanning. Follicular fluids were aspirated from the preovulatory follicles on days 0 and 29 of the experiment and analyzed for phthalate metabolites and estradiol concentration. The aspirated follicular fluid was used as maturation medium for in-vitro embryo production. Findings revealed that DEHP impairs the pattern of follicular development, with a prominent effect on dominant follicles. The diameter and growth rate of the first- and second-wave dominant follicles were lower (P < 0.05) in the DEHP-treated group. Estradiol concentration in the follicular fluid was lower in the DEHP-treated group than in controls, and associated with a higher number of follicular pathologies (follicle diameter >25 mm). The pattern of growth and regression of the corpus luteum differed between groups, with a lower volume in the DEHP-treated group (P < 0.05). The follicular fluid aspirated from the DEHP-treated group, but not the controls, contained 23 nM mono(2-ethylhexyl) phthalate. Culturing of cumulus oocyte complexes in the follicular fluid aspirated from DEHP-treated cows reduced the proportion of oocytes progressing to the MII stage, and the proportions of 2- to 4-cell-stage embryos (P < 0.04) and 7-day blastocysts (P < 0.06). The results describe the risk associated with acute exposure to DEHP and its deleterious carryover effects on ovarian function, nuclear maturation and oocyte developmental competence. PMID:26154164

Residual life assessment of the SSME/ATD HPOTP turnaround duct (TAD)

NASA Technical Reports Server (NTRS)

Gross, R. Steven

1996-01-01

This paper is concerned with the prediction of the low cycle thermal fatigue behavior of a component in a developmental (ATD) high pressure liquid oxygen turbopump (HPOTP) for the Space Shuttle Main Engine (SSME). This component is called the Turnaround Duct (TAD). The TAD is a complex single piece casting of MAR-M-247 material. Its function is to turn the hot turbine exhaust gas (1200 F hydrogen rich gas steam) such that it can exhaust radially out of the turbopump. In very simple terms, the TAD consists of two rings connected axially by 22 hollow airfoil shaped struts with the turning vanes placed at the top, middle, and bottom of each strut. The TAD is attached to the other components of the pump via bolts passing through 14 of the 22 struts. Of the remaining 8 struts, four are equally spaced (90 deg interval) and containing a cooling tube through which liquid hydrogen passes on its way to cool the shaft bearing assemblies. The remaining 4 struts are empty. One of the pump units in the certification test series was destructively examined after 22 test firings. Substantial axial cracking was found in two of the struts which contain cooling tubes. None of the other 20 struts showed any sign of internal cracking. This unusual low cycle thermal fatigue behavior within the two cooling tube struts is the focus of this study.

Essential Dosage-Dependent Functions of the Transcription Factor Yin Yang 1 in Late Embryonic Development and Cell Cycle Progression†

PubMed Central

Affar, El Bachir; Gay, Frédérique; Shi, Yujiang; Liu, Huifei; Huarte, Maite; Wu, Su; Collins, Tucker; Li, En; Shi, Yang

2006-01-01

Constitutive ablation of the Yin Yang 1 (YY1) transcription factor in mice results in peri-implantation lethality. In this study, we used homologous recombination to generate knockout mice carrying yy1 alleles expressing various amounts of YY1. Phenotypic analysis of yy1 mutant embryos expressing ∼75%, ∼50%, and ∼25% of the normal complement of YY1 identified a dosage-dependent requirement for YY1 during late embryogenesis. Indeed, reduction of YY1 levels impairs embryonic growth and viability in a dose-dependent manner. Analysis of the corresponding mouse embryonic fibroblast cells also revealed a tight correlation between YY1 dosage and cell proliferation, with a complete ablation of YY1 inducing cytokinesis failure and cell cycle arrest. Consistently, RNA interference-mediated inhibition of YY1 in HeLa cells prevents cytokinesis, causes proliferative arrest, and increases cellular sensitivity to various apoptotic agents. Genome-wide expression profiling identified a plethora of YY1 target genes that have been implicated in cell growth, proliferation, cytokinesis, apoptosis, development, and differentiation, suggesting that YY1 coordinates multiple essential biological processes through a complex transcriptional network. These data not only shed new light on the molecular basis for YY1 developmental roles and cellular functions, but also provide insight into the general mechanisms controlling eukaryotic cell proliferation, apoptosis, and differentiation. PMID:16611997

Managing Contextual Complexity in an Experiential Learning Course: A Dynamic Systems Approach through the Identification of Turning Points in Students' Emotional Trajectories

PubMed Central

Nogueiras, Gloria; Kunnen, E. Saskia; Iborra, Alejandro

2017-01-01

This study adopts a dynamic systems approach to investigate how individuals successfully manage contextual complexity. To that end, we tracked individuals' emotional trajectories during a challenging training course, seeking qualitative changes–turning points—and we tested their relationship with the perceived complexity of the training. The research context was a 5-day higher education course based on process-oriented experiential learning, and the sample consisted of 17 students. The students used a five-point Likert scale to rate the intensity of 16 emotions and the complexity of the training on 8 measurement points. Monte Carlo permutation tests enabled to identify 30 turning points in the 272 emotional trajectories analyzed (17 students * 16 emotions each). 83% of the turning points indicated a change of pattern in the emotional trajectories that consisted of: (a) increasingly intense positive emotions or (b) decreasingly intense negative emotions. These turning points also coincided with particularly complex periods in the training as perceived by the participants (p = 0.003, and p = 0.001 respectively). The relationship between positively-trended turning points in the students' emotional trajectories and the complexity of the training may be interpreted as evidence of a successful management of the cognitive conflict arising from the clash between the students' prior ways of meaning-making and the challenging demands of the training. One of the strengths of this study is that it provides a relatively simple procedure for identifying turning points in developmental trajectories, which can be applied to various longitudinal experiences that are very common in educational and developmental contexts. Additionally, the findings contribute to sustaining that the assumption that complex contextual demands lead unfailingly to individuals' learning is incomplete. Instead, it is how individuals manage complexity which may or may not lead to learning. Finally, this study can also be considered a first step in research on the developmental potential of process-oriented experiential learning training. PMID:28515703

Incremental learning of skill collections based on intrinsic motivation

PubMed Central

Metzen, Jan H.; Kirchner, Frank

2013-01-01

Life-long learning of reusable, versatile skills is a key prerequisite for embodied agents that act in a complex, dynamic environment and are faced with different tasks over their lifetime. We address the question of how an agent can learn useful skills efficiently during a developmental period, i.e., when no task is imposed on him and no external reward signal is provided. Learning of skills in a developmental period needs to be incremental and self-motivated. We propose a new incremental, task-independent skill discovery approach that is suited for continuous domains. Furthermore, the agent learns specific skills based on intrinsic motivation mechanisms that determine on which skills learning is focused at a given point in time. We evaluate the approach in a reinforcement learning setup in two continuous domains with complex dynamics. We show that an intrinsically motivated, skill learning agent outperforms an agent which learns task solutions from scratch. Furthermore, we compare different intrinsic motivation mechanisms and how efficiently they make use of the agent's developmental period. PMID:23898265

Visualizing the 3D Architecture of Multiple Erythrocytes Infected with Plasmodium at Nanoscale by Focused Ion Beam-Scanning Electron Microscopy

PubMed Central

Soares Medeiros, Lia Carolina; De Souza, Wanderley; Jiao, Chengge; Barrabin, Hector; Miranda, Kildare

2012-01-01

Different methods for three-dimensional visualization of biological structures have been developed and extensively applied by different research groups. In the field of electron microscopy, a new technique that has emerged is the use of a focused ion beam and scanning electron microscopy for 3D reconstruction at nanoscale resolution. The higher extent of volume that can be reconstructed with this instrument represent one of the main benefits of this technique, which can provide statistically relevant 3D morphometrical data. As the life cycle of Plasmodium species is a process that involves several structurally complex developmental stages that are responsible for a series of modifications in the erythrocyte surface and cytoplasm, a high number of features within the parasites and the host cells has to be sampled for the correct interpretation of their 3D organization. Here, we used FIB-SEM to visualize the 3D architecture of multiple erythrocytes infected with Plasmodium chabaudi and analyzed their morphometrical parameters in a 3D space. We analyzed and quantified alterations on the host cells, such as the variety of shapes and sizes of their membrane profiles and parasite internal structures such as a polymorphic organization of hemoglobin-filled tubules. The results show the complex 3D organization of Plasmodium and infected erythrocyte, and demonstrate the contribution of FIB-SEM for the obtainment of statistical data for an accurate interpretation of complex biological structures. PMID:22432024

Developmental Changes for the Hemolymph Metabolome of Silkworm (Bombyx moriL.)

PubMed Central

Zhou, Lihong; Li, Huihui; Hao, Fuhua; Li, Ning; Liu, Xin; Wang, Guoliang; Wang, Yulan; Tang, Huiru

2015-01-01

Silkworm (Bombyx mori) is a lepidopteran-holometabolic model organism. To understand its developmental biochemistry, we characterized the larval hemolymph metabonome from the third instar to prepupa stage using 1H NMR spectroscopy whilst hemolymph fatty acid composition using GC-FID/MS. We unambiguously assigned more than 60 metabolites, among which tyrosine-o-β-glucuronide, mesaconate, homocarnosine, and picolinate were reported for the first time from the silkworm hemolymph. Phosphorylcholine was the most abundant metabolite in all developmental stages with exception for the periods before the third and fourth molting. We also found obvious developmental dependence for the hemolymph metabonome involving multiple pathways including protein biosyntheses, glycolysis, TCA cycle, the metabolisms of choline amino acids, fatty acids, purines, and pyrimidines. Most hemolymph amino acids had two elevations during the feeding period of the fourth instar and prepupa stage. Trehalose was the major blood sugar before day 8 of the fifth instar, whereas glucose became the major blood sugar after spinning. C16:0, C18:0 and its unsaturated forms were dominant fatty acids in hemolymph. The developmental changes of hemolymph metabonome were associated with dietary nutrient intakes, biosyntheses of cell membrane, pigments, proteins, and energy metabolism. These findings offered essential biochemistry information in terms of the dynamic metabolic changes during silkworm development. PMID:25825269

A Transcriptome Atlas of Physcomitrella patens Provides Insights into the Evolution and Development of Land Plants.

PubMed

Ortiz-Ramírez, Carlos; Hernandez-Coronado, Marcela; Thamm, Anna; Catarino, Bruno; Wang, Mingyi; Dolan, Liam; Feijó, José A; Becker, Jörg D

2016-02-01

Identifying the genetic mechanisms that underpin the evolution of new organ and tissue systems is an aim of evolutionary developmental biology. Comparative functional genetic studies between angiosperms and bryophytes can define those genetic changes that were responsible for developmental innovations. Here, we report the generation of a transcriptome atlas covering most phases in the life cycle of the model bryophyte Physcomitrella patens, including detailed sporophyte developmental progression. We identified a comprehensive set of sporophyte-specific transcription factors, and found that many of these genes have homologs in angiosperms that function in developmental processes such as flowering and shoot branching. Deletion of the PpTCP5 transcription factor results in development of supernumerary sporangia attached to a single seta, suggesting that it negatively regulates branching in the moss sporophyte. Given that TCP genes repress branching in angiosperms, we suggest that this activity is ancient. Finally, comparison of P. patens and Arabidopsis thaliana transcriptomes led us to the identification of a conserved core of transcription factors expressed in tip-growing cells. We identified modifications in the expression patterns of these genes that could account for developmental differences between P. patens tip-growing cells and A. thaliana pollen tubes and root hairs. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

Developmental Changes for the Hemolymph Metabolome of Silkworm (Bombyx mori L.).

PubMed

Zhou, Lihong; Li, Huihui; Hao, Fuhua; Li, Ning; Liu, Xin; Wang, Guoliang; Wang, Yulan; Tang, Huiru

2015-05-01

Silkworm (Bombyx mori) is a lepidopteran-holometabolic model organism. To understand its developmental biochemistry, we characterized the larval hemolymph metabonome from the third instar to prepupa stage using (1)H NMR spectroscopy whilst hemolymph fatty acid composition using GC-FID/MS. We unambiguously assigned more than 60 metabolites, among which tyrosine-o-β-glucuronide, mesaconate, homocarnosine, and picolinate were reported for the first time from the silkworm hemolymph. Phosphorylcholine was the most abundant metabolite in all developmental stages with exception for the periods before the third and fourth molting. We also found obvious developmental dependence for the hemolymph metabonome involving multiple pathways including protein biosyntheses, glycolysis, TCA cycle, the metabolisms of choline amino acids, fatty acids, purines, and pyrimidines. Most hemolymph amino acids had two elevations during the feeding period of the fourth instar and prepupa stage. Trehalose was the major blood sugar before day 8 of the fifth instar, whereas glucose became the major blood sugar after spinning. C16:0, C18:0 and its unsaturated forms were dominant fatty acids in hemolymph. The developmental changes of hemolymph metabonome were associated with dietary nutrient intakes, biosyntheses of cell membrane, pigments, proteins, and energy metabolism. These findings offered essential biochemistry information in terms of the dynamic metabolic changes during silkworm development.

Multifractality as a Measure of Complexity in Solar Flare Activity

NASA Astrophysics Data System (ADS)

Sen, Asok K.

2007-03-01

In this paper we use the notion of multifractality to describe the complexity in H α flare activity during the solar cycles 21, 22, and 23. Both northern and southern hemisphere flare indices are analyzed. Multifractal behavior of the flare activity is characterized by calculating the singularity spectrum of the daily flare index time series in terms of the Hölder exponent. The broadness of the singularity spectrum gives a measure of the degree of multifractality or complexity in the flare index data. The broader the spectrum, the richer and more complex is the structure with a higher degree of multifractality. Using this broadness measure, complexity in the flare index data is compared between the northern and southern hemispheres in each of the three cycles, and among the three cycles in each of the two hemispheres. Other parameters of the singularity spectrum can also provide information about the fractal properties of the flare index data. For instance, an asymmetry to the left or right in the singularity spectrum indicates a dominance of high or low fractal exponents, respectively, reflecting a relative abundance of large or small fluctuations in the total energy emitted by the flares. Our results reveal that in the even (22nd) cycle the singularity spectra are very similar for the northern and southern hemispheres, whereas in the odd cycles (21st and 23rd) they differ significantly. In particular, we find that in cycle 21, the northern hemisphere flare index data have higher complexity than its southern counterpart, with an opposite pattern prevailing in cycle 23. Furthermore, small-scale fluctuations in the flare index time series are predominant in the northern hemisphere in the 21st cycle and are predominant in the southern hemisphere in the 23rd cycle. Based on these findings one might suggest that, from cycle to cycle, there exists a smooth switching between the northern and southern hemispheres in the multifractality of the flaring process. This new observational result may bring an insight into the mechanisms of the solar dynamo operation and may also be useful for forecasting solar cycles.

Reading, Complexity and the Brain

ERIC Educational Resources Information Center

Goswami, Usha

2008-01-01

Brain imaging offers a new technology for understanding the acquisition of reading by children. It can contribute novel evidence concerning the key mechanisms supporting reading, and the brain systems that are involved. The extensive neural architecture that develops to support efficient reading testifies to the complex developmental processes…

DIRECT AND PHOTOACTIVATED TOXICITY OF A COMPLEX PETROLEUM MIXTURE: A COMPARISON OF SOLUBILIZATION METHODS

EPA Science Inventory

This work addresses several issues associated with the toxicity of a complex petroleum mixture (combined kerosene/diesel and crude oil), including developmental effects and early lifestage mortality, method of solubilization, and potential photo-activated and photo-modified toxic...

Graduate Education to Facilitate Interdisciplinary Research Collaboration: Identifying Individual Competencies and Developmental Activities

ERIC Educational Resources Information Center

Holt, Valerie Ciocca

2013-01-01

Interdisciplinary research collaborations (IDRC) are considered essential for addressing the most complex global community problems concerning science, health, education, energy, the environment, and society. In spite of technological advances, supportive funding, and even researcher proclivity to collaborate, these complex interdisciplinary…

The symphony of the damned: racial discourse, complex political emergencies and humanitarian aid.

PubMed

Duffield, M

1996-09-01

This paper concerns the manner in which the West is responding to protracted political crises beyond its borders. It examines the conceptual world-view that aid agencies bring to complex emergencies and which shapes action. The paper provides an analysis of developmentalism. That is, the currently dominant idea of development which is an adapted form of multiculturalism. It is based on the empowerment of cultural differences and the relativisation of progress. As a variant of multiculturalism, developmentalism is part of Western racial discourse. In terms of understanding conflict, it establishes a mirror-image relationship with new rascist ideas premised on cultural pluralism inevitably leading to social breakdown, violence and anarchy. To the contrary, with its functional view of social harmony, libertine developmentalism claims that even unresolved political crisis constitutes a development opportunity. Developmentalism, like culturalism generally, is incapable of analysing power. It therefore cannot understand the effects and significance of its own organisational forms. Moreover, since the absence of power translates into operational neutrality in a war zone, it is also unable to analyse the nature of new political formations emerging in the global periphery. That is, the so-called weak or failed states, warlords and so on. This functional ignorance has allowed a widespread incorporation of humanitarian aid into the fabric of political violence. Developmentalism is an essential underpinning for the growing organisational accommodation to ongoing conflict and eroding standards of justice and accountability.

RNAi pathways contribute to developmental history-dependent phenotypic plasticity in C. elegans

PubMed Central

Hall, Sarah E.; Chirn, Gung-Wei; Lau, Nelson C.; Sengupta, Piali

2013-01-01

Early environmental experiences profoundly influence adult phenotypes through complex mechanisms that are poorly understood. We previously showed that adult Caenorhabditis elegans that transiently passed through the stress-induced dauer larval stage (post-dauer adults) exhibit significant changes in gene expression profiles, chromatin states, and life history traits when compared with adults that bypassed the dauer stage (control adults). These wild-type, isogenic animals of equivalent developmental stages exhibit different signatures of molecular marks that reflect their distinct developmental trajectories. To gain insight into the mechanisms that contribute to these developmental history-dependent phenotypes, we profiled small RNAs from post-dauer and control adults by deep sequencing. RNA interference (RNAi) pathways are known to regulate genome-wide gene expression both at the chromatin and post-transcriptional level. By quantifying changes in endogenous small interfering RNA (endo-siRNA) levels in post-dauer as compared with control animals, our analyses identified a subset of genes that are likely targets of developmental history-dependent reprogramming through a complex RNAi-mediated mechanism. Mutations in specific endo-siRNA pathways affect expected gene expression and chromatin state changes for a subset of genes in post-dauer animals, as well as disrupt their increased brood size phenotype. We also find that both chromatin state and endo-siRNA distribution in dauers are unique, and suggest that remodeling in dauers provides a template for the subsequent establishment of adult post-dauer profiles. Our results indicate a role for endo-siRNA pathways as a contributing mechanism to early experience-dependent phenotypic plasticity in adults, and describe how developmental history can program adult physiology and behavior via epigenetic mechanisms. PMID:23329696

Defective pulmonary innervation and autonomic imbalance in congenital diaphragmatic hernia

PubMed Central

Lath, Nikesh R.; Galambos, Csaba; Rocha, Alejandro Best; Malek, Marcus; Gittes, George K.

2012-01-01

Congenital diaphragmatic hernia (CDH) is associated with significant mortality due to lung hypoplasia and pulmonary hypertension. The role of embryonic pulmonary innervation in normal lung development and lung maldevelopment in CDH has not been defined. We hypothesize that developmental defects of intrapulmonary innervation, in particular autonomic innervation, occur in CDH. This abnormal embryonic pulmonary innervation may contribute to lung developmental defects and postnatal physiological derangement in CDH. To define patterns of pulmonary innervation in CDH, human CDH and control lung autopsy specimens were stained with the pan-neural marker S-100. To further characterize patterns of overall and autonomic pulmonary innervation during lung development in CDH, the murine nitrofen model of CDH was utilized. Immunostaining for protein gene product 9.5 (a pan-neuronal marker), tyrosine hydroxylase (a sympathetic marker), vesicular acetylcholine transporter (a parasympathetic marker), or VIP (a parasympathetic marker) was performed on lung whole mounts and analyzed via confocal microscopy and three-dimensional reconstruction. Peribronchial and perivascular neuronal staining pattern is less complex in human CDH than control lung. In mice, protein gene product 9.5 staining reveals less complex neuronal branching and decreased neural tissue in nitrofen-treated lungs from embryonic day 12.5 to 16.5 compared with controls. Furthermore, nitrofen-treated embryonic lungs exhibited altered autonomic innervation, with a relative increase in sympathetic nerve staining and a decrease in parasympathetic nerve staining compared with controls. These results suggest a primary defect in pulmonary neural developmental in CDH, resulting in less complex neural innervation and autonomic imbalance. Defective embryonic pulmonary innervation may contribute to lung developmental defects and postnatal physiological derangement in CDH. PMID:22114150

On the interrelation of multiplication and division in secondary school children

PubMed Central

Huber, Stefan; Fischer, Ursula; Moeller, Korbinian; Nuerk, Hans-Christoph

2013-01-01

Multiplication and division are conceptually inversely related: Each division problem can be transformed into as a multiplication problem and vice versa. Recent research has indicated strong developmental parallels between multiplication and division in primary school children. In this study, we were interested in (i) whether these developmental parallels persist into secondary school, (ii) whether similar developmental parallels can be observed for simple and complex problems, (iii) whether skill level modulates this relationship, and (iv) whether the correlations are specific and not driven by general cognitive or arithmetic abilities. Therefore, we assessed performance of 5th and 6th graders attending two secondary school types of the German educational system in simple and complex multiplication as well as division while controlling for non-verbal intelligence, short-term memory, and other arithmetic abilities. Accordingly, we collected data from students differing in skills levels due to either age (5th < 6th grade) or school type (general < intermediate secondary school). We observed moderate to strong bivariate and partial correlations between multiplication and division with correlations being higher for simple tasks but nevertheless reliable for complex tasks. Moreover, the association between simple multiplication and division depended on students' skill levels as reflected by school types, but not by age. Partial correlations were higher for intermediate than for general secondary school children. In sum, these findings emphasize the importance of the inverse relationship between multiplication and division which persists into later developmental stages. However, evidence for skill-related differences in the relationship between multiplication and division was restricted to the differences for school types. PMID:24133476

p21 stability: linking chaperones to a cell cycle checkpoint.

PubMed

Liu, Geng; Lozano, Guillermina

2005-02-01

Progression through the cell cycle is regulated by numerous proteins, one of which is the cyclin-dependent kinase inhibitor, p21. A new study identifies a novel protein complex that stabilizes p21. The stability of this complex is critical in effecting the p53-mediated cell cycle checkpoint.

Prenatal stress and development: beyond the single cause and effect paradigm.

PubMed

Hamlin, Heather J

2012-12-01

Our awareness of the causes of stress-induced developmental dysfunction has increased dramatically over the past decade, and it is becoming increasingly clear that a number of factors can have considerable impacts on the developing fetus. Although there is a tendency in investigations of developmental teratogens to attribute specific causes to adverse fetal outcomes, it is important we recognize that for most developmental dysfunctions it is unlikely a single cause, but yet a series of environmental insults combined with genetic predisposition that ultimately leads to a disease state. Nonetheless, a number of developmental teratogens, such as maternal psychological stress and chemical exposures, have been shown to increase the likelihood of developmental defects. These defects can manifest during development, leading to observable birth defects, or could become evident long after birth, even into adulthood. In addition, epigenetic mutations in the germline can alter the phenotype of successive generations through transgenerational inheritance, and in this way environmental factors can alter the developmental outcomes and disease predispositions of future generations. Understanding this complexity is essential to interpretations of causality in the studies of stress-induced developmental dysfunction and needs to be fully considered to more effectively interpret potential outcomes. Copyright © 2013 Wiley Periodicals, Inc.

Drosophila Lin-52 Acts in Opposition to Repressive Components of the Myb-MuvB/dREAM Complex

PubMed Central

Lewis, Peter W.; Sahoo, Debashis; Geng, Cuiyun; Bell, Maren

2012-01-01

The Drosophila melanogaster Myb-MuvB/dREAM complex (MMB/dREAM) participates in both the activation and repression of developmentally regulated genes and origins of DNA replication. Mutants in MMB subunits exhibit diverse phenotypes, including lethality, eye defects, reduced fecundity, and sterility. Here, we used P-element excision to generate mutations in lin-52, which encodes the smallest subunit of the MMB/dREAM complex. lin-52 is required for viability, as null mutants die prior to pupariation. The generation of somatic and germ line mutant clones indicates that lin-52 is required for adult eye development and for early embryogenesis via maternal effects. Interestingly, the maternal-effect embryonic lethality, larval lethality, and adult eye defects could be suppressed by mutations in other subunits of the MMB/dREAM complex. These results suggest that a partial MMB/dREAM complex is responsible for the lethality and eye defects of lin-52 mutants. Furthermore, these findings support a model in which the Lin-52 and Myb proteins counteract the repressive activities of the other members of the MMB/dREAM complex at specific genomic loci in a developmentally controlled manner. PMID:22688510

Representing Ontogeny Through Ontology: A Developmental Biologist’s Guide to The Gene Ontology

PubMed Central

Hill, David P.; Berardini, Tanya Z.; Howe, Douglas G.; Van Auken, Kimberly M.

2010-01-01

Developmental biology, like many other areas of biology, has undergone a dramatic shift in the perspective from which developmental processes are viewed. Instead of focusing on the actions of a handful of genes or functional RNAs, we now consider the interactions of large functional gene networks and study how these complex systems orchestrate the unfolding of an organism, from gametes to adult. Developmental biologists are beginning to realize that understanding ontogeny on this scale requires the utilization of computational methods to capture, store and represent the knowledge we have about the underlying processes. Here we review the use of the Gene Ontology (GO) to study developmental biology. We describe the organization and structure of the GO and illustrate some of the ways we use it to capture the current understanding of many common developmental processes. We also discuss ways in which gene product annotations using the GO have been used to ask and answer developmental questions in a variety of model developmental systems. We provide suggestions as to how the GO might be used in more powerful ways to address questions about development. Our goal is to provide developmental biologists with enough background about the GO that they can begin to think about how they might use the ontology efficiently and in the most powerful ways possible. PMID:19921742

"I Disagree!" Said a Second-Grader: Butterflies, Conflict, and Literate Thinking.

ERIC Educational Resources Information Center

Salyer, David M.

2000-01-01

Describes how an inquiry-based science project on the life cycle of butterflies provided a developmentally appropriate learning experience in a first and second grade multiage classroom. Maintains that the critical exchange of ideas among students made students' thinking available for inspection, and allowed students to use their talk as a tool…

Development of life stages of Leptotrombidium imphalum and Leptotrombidium chiangraiensis (Acari: Trombiculidae) uninfected and infected with the scrub typhus rickettsia, Orientia tsustugamushi

USDA-ARS?s Scientific Manuscript database

Leptotrombidium chiangraiensis Tanskul and Linthicum and Leptotrombidium imphalum Vercammen-Grandjean are important vectors of scrub typhus in ricefield habitats in northern Thailand. The developmental biology of all stages of the life cycle of two generations of mites infected with Orientia tsutsug...

The Writing Process: Effects of Life-Span Development on Imaging.

ERIC Educational Resources Information Center

Shock, Diane Hahn

A qualitative study focused on incubation and illumination within the act of writing to determine if life-span development affects image production during these creative, cognitive acts. Sixteen subjects of both sexes from four age groups represented major developmental stages in the life cycle. The research design provided two 90-minute sessions…

A Cognitive Developmental Approach to Question Asking: A Learning Cycle-Distancing Model.

ERIC Educational Resources Information Center

Sigel, Irving E.; Kelley, Todd D.

The role of questioning techniques in the classroom is discussed, with particular emphasis on the cyclical nature of teacher-student dialogues. Excerpts from transcripts of actual dialogues are also analyzed. According to the model, based on Piaget's theory of cognitive development, the questioning strategies are designed to enhance the student's…

Social Anxiety and Peer Helping in Adolescent Addiction Treatment

ERIC Educational Resources Information Center

Pagano, Maria E.; Wang, Alexandra R.; Rowles, Brieana M.; Lee, Matthew T.; Johnson, Byron R.

2015-01-01

The developmental need to fit in may lead to higher alcohol and other drug use among socially anxious youths which exacerbates the drink/trouble cycle. In treatment, youths with social anxiety disorder (SAD) may avoid participating in therapeutic activities with risk of negative peer appraisal. Peer-helping is a low-intensity, social activity in…

From Embryo to Adult: Hematopoiesis along the Drosophila Life Cycle.

PubMed

Ramond, Elodie; Meister, Marie; Lemaitre, Bruno

2015-05-26

Studies on Drosophila hematopoiesis have thus far focused on the embryonic and larval origin of hemocytes, the fly blood cells. In this issue of Developmental Cell, Ghosh et al. (2015) identify adult hematopoietic hubs containing progenitors that can differentiate into different blood cell types. Copyright © 2015 Elsevier Inc. All rights reserved.

Coprinus Cinereus: An Ideal Organism for Studies of Genetics and Developmental Biology.

ERIC Educational Resources Information Center

Moore, David; Pukkila, Patricia J.

1985-01-01

Ink-cap mushrooms can be easily grown in culture and provide students with ideal material for studying a wide range of biological problems. The life cycle is discussed extensively with hints for inoculating plates, staining, and isolating basidiospores. Exercises are easy, safe, and provide opportunity to demonstrate several microbiological…

Revision and Evaluation of a Course in Behavioral Sciences for Undergraduate Medical Students.

ERIC Educational Resources Information Center

McGuire, Frederick L.; Friedmann, Claude T. H.

1981-01-01

The new teaching format of a behavioral science course at the University of California, Irvine, College of Medicine is described. Specific objectives were to present an introduction of life's developmental cycles, the nature of mind-body relationships, and dynamics of the doctor-patient relationship, and to develop interviewing skills. (MLW)

76 FR 26736 - Center for Scientific Review; Notice of Closed Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-09

... due to the timing limitations imposed by the review and funding cycle. Name of Committee: Molecular....gov . Name of Committee: Molecular, Cellular and Developmental Neuroscience Integrated Review Group, Cellular and Molecular Biology of Glia Study Section. Date: June 2-3, 2011. Time: 8 a.m. to 4 p.m. Agenda...

Embryonic development rates of northern grasshoppers (Orthoptera: Acrididae): implications for climate change and habitat management

USDA-ARS?s Scientific Manuscript database

Temperature-dependent rates of embryonic development are a primary determinant of the life cycle of many species of grasshoppers which, in cold climates, spend two winters in the egg stage. Knowledge of embryonic developmental rates is important for an assessment of the effects of climate change and...

"Play" across the Life Cycle: From Initiative to Integrity to Transcendence

ERIC Educational Resources Information Center

Jones, Elizabeth

2011-01-01

In this autobiographical journey through life-span developmental theory, the author reflects on her life as a player, embedding it in the context of Erik Erikson and Joan Erikson's stages of human development. The author builds on these basic ideas--theory, storytelling, play, and development--and defines them as simply as possible.

Income Disparities in Preschool Outcomes and the Role of Family, Child, and Parenting Factors

ERIC Educational Resources Information Center

Kohen, Dafna; Guèvremont, Anne

2014-01-01

The current study examined income disparities in a comprehensive set of preschoolers' outcomes (verbal ability, developmental skills, number knowledge, and hyperactivity) and the factors that could reduce differences in outcomes between children in the lowest and highest household income quartiles. Findings using Cycle 6 data from the Canadian…

Expansive Learning in a Library: Actions, Cycles and Deviations from Instructional Intentions

ERIC Educational Resources Information Center

Engestrom, Yrjo; Rantavuori, Juhana; Kerosuo, Hannele

2013-01-01

The theory of expansive learning has been applied in a large number of studies on workplace learning and organizational change. However, detailed comprehensive analyses of entire developmental interventions based on the theory of expansive learning do not exist. Such a study is needed to examine the empirical usability and methodological rigor…

Living in Partner-Violent Families: Developmental Links to Antisocial Behavior and Relationship Violence

ERIC Educational Resources Information Center

Ireland, Timothy O.; Smith, Carolyn A.

2009-01-01

Links between living in a partner-violent home and subsequent aggressive and antisocial behavior are suggested by the "cycle of violence" hypothesis derived from social learning theory. Although there is some empirical support, to date, findings have been generally limited to cross-sectional studies predominantly of young children, or…

A phenomenographic study of the ability to address complex socio-technical systems via variation theory

NASA Astrophysics Data System (ADS)

Mendoza Garcia, John A.

Sometimes engineers fail when addressing the inherent complexity of socio-technical systems because they lack the ability to address the complexity of socio-technical systems. Teaching undergraduate engineering students how to address complex socio-technical systems, has been an educational endeavor at different levels ranging from kindergarten to post-graduate education. The literature presents different pedagogical strategies and content to reach this goal. However, there are no existing empirically-based assessments guided by a learning theory. This may be because at the same time explanations of how the skill is developed are scarce. My study bridges this gap, and I propose a developmental path for the ability to address the complex socio-technical systems via Variation Theory, and according to the conceptual framework provided by Variation Theory, my research question was "What are the various ways in which engineers address complex socio-technical systems?" I chose the research approach of phenomenography to answer my research question. I also chose to use a blended approach, Marton's approach for finding the dimensions of variation, and the developmental approach (Australian) for finding a hierarchical relationship between the dimensions. Accordingly, I recruited 25 participants with different levels of experience with addressing complex socio-technical systems and asked them all to address the same two tasks: A design of a system for a county, and a case study in a manufacturing firm. My outcome space is a nona-dimensional (nine) developmental path for the ability to address the complexity in socio-technical systems, and I propose 9 different ways of experiencing the complexity of a socio-technical system. The findings of this study suggest that the critical aspects that are needed to address the complexity of socio-technical systems are: being aware of the use of models, the ecosystem around, start recognizing different boundaries, being aware of time as a factor, recognizing the part-whole relationships, make effort in tailoring a solution that responds to stakeholders' needs, find the right problem, giving voice to others, and finally be aware of the need to iterate.

The MADS-box XAANTAL1 increases proliferation at the Arabidopsis root stem-cell niche and participates in transition to differentiation by regulating cell-cycle components.

PubMed

García-Cruz, Karla V; García-Ponce, Berenice; Garay-Arroyo, Adriana; Sanchez, María De La Paz; Ugartechea-Chirino, Yamel; Desvoyes, Bénédicte; Pacheco-Escobedo, Mario A; Tapia-López, Rosalinda; Ransom-Rodríguez, Ivan; Gutierrez, Crisanto; Alvarez-Buylla, Elena R

2016-07-29

Morphogenesis depends on the concerted modulation of cell proliferation and differentiation. Such modulation is dynamically adjusted in response to various external and internal signals via complex transcriptional regulatory networks that mediate between such signals and regulation of cell-cycle and cellular responses (proliferation, growth, differentiation). In plants, which are sessile, the proliferation/differentiation balance is plastically adjusted during their life cycle and transcriptional networks are important in this process. MADS-box genes are key developmental regulators in eukaryotes, but their role in cell proliferation and differentiation modulation in plants remains poorly studied. We characterize the XAL1 loss-of-function xal1-2 allele and overexpression lines using quantitative cellular and cytometry analyses to explore its role in cell cycle, proliferation, stem-cell patterning and transition to differentiation. We used quantitative PCR and cellular markers to explore if XAL1 regulates cell-cycle components and PLETHORA1 (PLT1) gene expression, as well as confocal microscopy to analyse stem-cell niche organization. We previously showed that XAANTAL1 (XAL1/AGL12) is necessary for Arabidopsis root development as a promoter of cell proliferation in the root apical meristem. Here, we demonstrate that XAL1 positively regulates the expression of PLT1 and important components of the cell cycle: CYCD3;1, CYCA2;3, CYCB1;1, CDKB1;1 and CDT1a In addition, we show that xal1-2 mutant plants have a premature transition to differentiation with root hairs appearing closer to the root tip, while endoreplication in these plants is partially compromised. Coincidently, the final size of cortex cells in the mutant is shorter than wild-type cells. Finally, XAL1 overexpression-lines corroborate that this transcription factor is able to promote cell proliferation at the stem-cell niche. XAL1 seems to be an important component of the networks that modulate cell proliferation/differentiation transition and stem-cell proliferation during Arabidopsis root development; it also regulates several cell-cycle components. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Identification of the meiotic life cycle stage of Trypanosoma brucei in the tsetse fly

PubMed Central

Peacock, Lori; Ferris, Vanessa; Sharma, Reuben; Sunter, Jack; Bailey, Mick; Carrington, Mark; Gibson, Wendy

2011-01-01

Elucidating the mechanism of genetic exchange is fundamental for understanding how genes for such traits as virulence, disease phenotype, and drug resistance are transferred between pathogen strains. Genetic exchange occurs in the parasitic protists Trypanosoma brucei, T. cruzi, and Leishmania major, but the precise cellular mechanisms are unknown, because the process has not been observed directly. Here we exploit the identification of homologs of meiotic genes in the T. brucei genome and demonstrate that three functionally distinct, meiosis-specific proteins are expressed in the nucleus of a single specific cell type, defining a previously undescribed developmental stage occurring within the tsetse fly salivary gland. Expression occurs in clonal and mixed infections, indicating that the meiotic program is an intrinsic but hitherto cryptic part of the developmental cycle of trypanosomes. In experimental crosses, expression of meiosis-specific proteins usually occurred before cell fusion. This is evidence of conventional meiotic division in an excavate protist, and the functional conservation of the meiotic machinery in these divergent organisms underlines the ubiquity and basal evolution of meiosis in eukaryotes. PMID:21321215

Toxicity assessment of diesel- and metal-contaminated soils through elutriate and solid phase assays with the slime mold Dictyostelium discoideum.

PubMed

Rodríguez-Ruiz, Amaia; Dondero, Francesco; Viarengo, Aldo; Marigómez, Ionan

2016-06-01

A suite of organisms from different taxonomical and ecological positions is needed to assess environmentally relevant soil toxicity. A new bioassay based on Dictyostelium is presented that is aimed at integrating slime molds into such a testing framework. Toxicity tests on elutriates and the solid phase developmental cycle assay were successfully applied to a soil spiked with a mixture of Zn, Cd, and diesel fuel freshly prepared (recently contaminated) and after 2 yr of aging. The elutriates of both soils provoked toxic effects, but toxicity was markedly lower in the aged soil. In the D. discoideum developmental cycle assay, both soils affected amoeba viability and aggregation, with fewer multicellular units, smaller fruiting bodies and, overall, inhibition of fruiting body formation. This assay is quick and requires small amounts of test soil, which might facilitate its incorporation into a multispecies multiple-endpoint toxicity bioassay battery suitable for environmental risk assessment in soils. Environ Toxicol Chem 2016;35:1413-1421. © 2015 SETAC. © 2015 SETAC.

Revealing the secret life of pre-implantation embryos by time-lapse monitoring: A review

PubMed Central

Faramarzi, Azita; Khalili, Mohammad Ali; Micara, Giulietta; Agha-Rahimi, Azam

2017-01-01

High implantation success following in vitro fertilization cycles are achieved via the transfer of embryos with the highest developmental competence. Multiple pregnancies as a result of the transfer of several embryos per cycle accompany with various complication. Thus, single-embryo transfer (SET) is the preferred practice in assisted reproductive technique (ART) treatment. In order to improve the pregnancy rate for SET, embryologists need reliable biomarkers to aid their selection of embryos with the highest developmental potential. Time-lapse technology is a noninvasive alternative conventional microscopic assessment. It provides uninterrupted and continues the survey of embryo development to transfer day. Today, there are four time-lapse systems that are commercially available for ART centers. In world and Iran, the first time lapse babies were born in 2010 and 2015, respectively, conceived by SET. Here, we review the use of time-lapse monitoring in the observation of embryogenesis as well as its role in SET. Although, the findings from our review support common use of time-lapse monitoring in ART centers; but, future large studies assessing this system in well-designed trials are necessary. PMID:28744520

Effects of Mentha suaveolens Essential Oil on Chlamydia trachomatis

PubMed Central

Sessa, Rosa; Di Pietro, Marisa; De Santis, Fiorenzo; Filardo, Simone; Ragno, Rino; Angiolella, Letizia

2015-01-01

Chlamydia trachomatis, the most common cause of sexually transmitted bacterial infection worldwide, has a unique biphasic developmental cycle alternating between the infectious elementary body and the replicative reticulate body. C. trachomatis is responsible for severe reproductive complications including pelvic inflammatory disease, ectopic pregnancy, and obstructive infertility. The aim of our study was to evaluate whether Mentha suaveolens essential oil (EOMS) can be considered as a promising candidate for preventing C. trachomatis infection. Specifically, we investigated the in vitro effects of EOMS towards C. trachomatis analysing the different phases of chlamydial developmental cycle. Our results demonstrated that EOMS was effective towards C. trachomatis, whereby it not only inactivated infectious elementary bodies but also inhibited chlamydial replication. Our study also revealed the effectiveness of EOMS, in combination with erythromycin, towards C. trachomatis with a substantial reduction in the minimum effect dose of antibiotic. In conclusion, EOMS treatment may represent a preventative strategy since it may reduce C. trachomatis transmission in the population and, thereby, reduce the number of new chlamydial infections and risk of developing of severe sequelae. PMID:25685793

Mutational Analysis of Cell Types in Tuberous Sclerosis Complex (TSC)

DTIC Science & Technology

2007-01-01

disorder resulting from mutations in the TSC1 or TSC2 genes that is associated with epilepsy, cognitive disability, and autism . TSC1/TSC2 gene mutations...cognitive disability, and autism . TSC1/TSC2 gene mutations lead to developmental alterations in brain structure known as tubers in over 80% of TSC...TSC (Sparagana and Roach, 2000). Comorbid neuropsychological disorders such as autism , mental retardation (MR), pervasive developmental disorder

The seasonal-cycle climate model

NASA Technical Reports Server (NTRS)

Marx, L.; Randall, D. A.

1981-01-01

The seasonal cycle run which will become the control run for the comparison with runs utilizing codes and parameterizations developed by outside investigators is discussed. The climate model currently exists in two parallel versions: one running on the Amdahl and the other running on the CYBER 203. These two versions are as nearly identical as machine capability and the requirement for high speed performance will allow. Developmental changes are made on the Amdahl/CMS version for ease of testing and rapidity of turnaround. The changes are subsequently incorporated into the CYBER 203 version using vectorization techniques where speed improvement can be realized. The 400 day seasonal cycle run serves as a control run for both medium and long range climate forecasts alsensitivity studies.

Signal relay during the life cycle of Dictyostelium.

PubMed

Mahadeo, Dana C; Parent, Carole A

2006-01-01

A fundamental property of multicellular organisms is signal relay, the process by which information is transmitted from one cell to another. The integration of external information, such as nutritional status or developmental cues, is critical to the function of organisms. In addition, the spatial organizations of multicellular organisms require intricate signal relay mechanisms. Signal relay is remarkably exhibited during the life cycle of the social amoebae Dictyostelium discoideum, a eukaryote that retains a simple way of life, yet it has greatly contributed to our knowledge of the mechanisms cells use to communicate and integrate information. This chapter focuses on the molecules and mechanisms that Dictyostelium employs during its life cycle to relay temporal and spatial cues that are required for survival.

Zebrafish model systems for developmental neurobehavioral toxicology.

PubMed

Bailey, Jordan; Oliveri, Anthony; Levin, Edward D

2013-03-01

Zebrafish offer many advantages that complement classic mammalian models for the study of normal development as well as for the teratogenic effects of exposure to hazardous compounds. The clear chorion and embryo of the zebrafish allow for continuous visualization of the anatomical changes associated with development, which, along with short maturation times and the capability of complex behavior, makes this model particularly useful for measuring changes to the developing nervous system. Moreover, the rich array of developmental, behavioral, and molecular benefits offered by the zebrafish have contributed to an increasing demand for the use of zebrafish in behavioral teratology. Essential for this endeavor has been the development of a battery of tests to evaluate a spectrum of behavior in zebrafish. Measures of sensorimotor plasticity, emotional function, cognition and social interaction have been used to characterize the persisting adverse effects of developmental exposure to a variety of chemicals including therapeutic drugs, drugs of abuse and environmental toxicants. In this review, we present and discuss such tests and data from a range of developmental neurobehavioral toxicology studies using zebrafish as a model. Zebrafish provide a key intermediate model between high throughput in vitro screens and the classic mammalian models as they have the accessibility of in vitro models and the complex functional capabilities of mammalian models. Copyright © 2013 Wiley Periodicals, Inc.

The effects of drought and disturbance on the growth and developmental instability of loblolly pine (Pinus taeda L.)

USGS Publications Warehouse

Graham, John H.; Duda, Jeffrey J.; Brown, Michelle L.; Kitchen, Stanley G.; Emlen, John M.; Malol, Jagadish; Bankstahl, Elizabeth; Krzysik, Anthony J.; Balbach, Harold E.; Freeman, D. Carl

2012-01-01

Ecological indicators provide early warning of adverse environmental change, helping land managers adaptively manage their resources while minimizing costly remediation. In 1999 and 2000, we studied two such indicators, growth and developmental instability, of loblolly pine (Pinus taeda L.) influenced by mechanized infantry training at Fort Benning, Georgia. Disturbed areas were used for military training; tracked and wheeled vehicles damaged vegetation and soils. Highly disturbed sites had fewer trees, diminished ground cover, warmer soils in the summer, and more compacted soils with a shallower A-horizon. We hypothesized that disturbance would decrease the growth of needles, branches, and tree rings, increase the complexity of tree rings, and increase the developmental instability of needles. Contrary to our expectations, however, disturbance enhanced growth in the first year of the study, possibly by reducing competition. In the second year, a drought reduced growth of branches and needles, eliminating the stimulatory effect of disturbance. Growth-ring widths increased with growing-season precipitation, and decreased with growing-season temperature over the last 40 years. Disturbance had no effect on tree-ring complexity, as measured by the Hurst exponent. Within-fascicle variation of current-year needle length, a measure of developmental instability, differed among the study populations, but appeared unrelated to mechanical disturbance or drought.

Cell migration analysis: A low-cost laboratory experiment for cell and developmental biology courses using keratocytes from fish scales.

PubMed

Prieto, Daniel; Aparicio, Gonzalo; Sotelo-Silveira, Jose R

2017-11-01

Cell and developmental processes are complex, and profoundly dependent on spatial relationships that change over time. Innovative educational or teaching strategies are always needed to foster deep comprehension of these processes and their dynamic features. However, laboratory exercises in cell and developmental biology at the undergraduate level do not often take into account the time dimension. In this article, we provide a laboratory exercise focused in cell migration, aiming to stimulate thinking in time and space dimensions through a simplification of more complex processes occurring in cell or developmental biology. The use of open-source tools for the analysis, as well as the whole package of raw results (available at http://github.com/danielprieto/keratocyte) make it suitable for its implementation in courses with very diverse budgets. Aiming to facilitate the student's transition from science-students to science-practitioners we propose an exercise of scientific thinking, and an evaluation method. This in turn is communicated here to facilitate the finding of common caveats and weaknesses in the process of producing simple scientific communications describing the results achieved. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(6):475-482, 2017. © 2017 The International Union of Biochemistry and Molecular Biology.

Zebrafish Model Systems for Developmental Neurobehavioral Toxicology

PubMed Central

Bailey, Jordan; Oliveri, Anthony; Levin, Edward D.

2014-01-01

Zebrafish offer many advantages that complement classic mammalian models for the study of normal development as well as for the teratogenic effects of exposure to hazardous compounds. The clear chorion and embryo of the zebrafish allow for continuous visualization of the anatomical changes associated with development, which, along with short maturation times and the capability of complex behavior, makes this model particularly useful for measuring changes to the developing nervous system. Moreover, the rich array of developmental, behavioral, and molecular benefits offered by the zebrafish have contributed to an increasing demand for the use of zebrafish in behavioral teratology. Essential for this endeavor has been the development of a battery of tests to evaluate a spectrum of behavior in zebrafish. Measures of sensorimotor plasticity, emotional function, cognition and social interaction have been used to characterize the persisting adverse effects of developmental exposure to a variety of chemicals including therapeutic drugs, drugs of abuse and environmental toxicants. In this review, we present and discuss such tests and data from a range of developmental neurobehavioral toxicology studies using zebrafish as a model. Zebrafish provide a key intermediate model between high throughput in vitro screens and the classic mammalian models as they have the accessibility of in vitro models and the complex functional capabilities of mammalian models. PMID:23723169

Smooth pursuit eye movement (SPEM) in patients with multiple complex developmental disorder (MCDD), a subtype of the pervasive developmental disorder.

PubMed

Lahuis, Bertine E; Van Engeland, Herman; Cahn, Wiepke; Caspers, Esther; Van der Geest, Jos N; Van der Gaag, Rutger Jan; Kemner, Chantal

2009-01-01

Multiple complex developmental disorder (MCDD) is a well-defined and validated behavioural subtype of pervasive developmental disorder-not otherwise specified (PDD-NOS) and is thought to be associated with a higher risk of developing a schizophrenic spectrum disorder. The question was addressed whether patients with MCDD show the same psychophysiological abnormalities as seen in patients with schizophrenia. Smooth pursuit eye movement (pursuit gain and saccadic parameters) was measured in children with either MCDD (n=18) or autism (n=18), and in age- and IQ-matched controls (n=36), as well as in a group of adult patients with schizophrenia (n=14) and a group of adult controls (n=17). We found the expected effect of lower velocity gain and increased number of saccades in schizophrenic patients. Children with MCDD also showed a lower velocity gain compared to controls children. In contrast, velocity gain was similar in autistic subjects and controls. No differences for velocity gain were found in a direct comparison between MCDD and autism. Saccadic parameters were not significantly different from controls in either MCDD or autistic subjects. Children with MCDD, like schizophrenic adults, show a reduced velocity gain, which could indicate that schizophrenia spectrum disorders and MCDD share (at least to some degree) a common neurobiological background.

Evolution and development of brain networks: from Caenorhabditis elegans to Homo sapiens.

PubMed

Kaiser, Marcus; Varier, Sreedevi

2011-01-01

Neural networks show a progressive increase in complexity during the time course of evolution. From diffuse nerve nets in Cnidaria to modular, hierarchical systems in macaque and humans, there is a gradual shift from simple processes involving a limited amount of tasks and modalities to complex functional and behavioral processing integrating different kinds of information from highly specialized tissue. However, studies in a range of species suggest that fundamental similarities, in spatial and topological features as well as in developmental mechanisms for network formation, are retained across evolution. 'Small-world' topology and highly connected regions (hubs) are prevalent across the evolutionary scale, ensuring efficient processing and resilience to internal (e.g. lesions) and external (e.g. environment) changes. Furthermore, in most species, even the establishment of hubs, long-range connections linking distant components, and a modular organization, relies on similar mechanisms. In conclusion, evolutionary divergence leads to greater complexity while following essential developmental constraints.

Unusual anal fin in a Devonian jawless vertebrate reveals complex origins of paired appendages

PubMed Central

Sansom, Robert S.; Gabbott, Sarah E.; Purnell, M. A.

2013-01-01

Jawed vertebrates (gnathostomes) have undergone radical anatomical and developmental changes in comparison with their jawless cousins (cyclostomes). Key among these is paired appendages (fins, legs and wings), which first evolved at some point on the gnathostome stem. The anatomy of fossil stem gnathostomes is, therefore, fundamental to our understanding of the nature and timing of the origin of this complex innovation. Here, we show that Euphanerops, a fossil jawless fish from the Devonian, possessed paired anal-fin radials, but no pectoral or pelvic fins. This unique condition occurs at an early stage on the stem-gnathostome lineage. This condition, and comparison with the varied condition of paired fins in other ostracoderms, indicates that there was a large amount of developmental plasticity during this episode—rather than a gradual evolution of this complex feature. Apparently, a number of different clades were exploring morphospace or undergoing multiple losses. PMID:23576777

Mammalian Cardiovascular Patterning as Determined by Hemodynamic Forces and Blood Vessel Genetics

NASA Astrophysics Data System (ADS)

Anderson, Gregory Arthur

Cardiovascular development is a process that involves the timing of multiple molecular events, and numerous subtle three-dimensional conformational changes. Traditional developmental biology techniques have provided large quantities of information as to how these complex organ systems develop. However, the major drawback of the majority of current developmental biological imaging is that they are two-dimensional in nature. It is now well recognized that circulation of blood is required for normal patterning and remodeling of blood vessels. Normal blood vessel formation is dependent upon a complex network of signaling pathways, and genetic mutations in these pathways leads to impaired vascular development, heart failure, and lethality. As such, it is not surprising that mutant mice with aberrant cardiovascular patterning are so common, since normal development requires proper coordination between three systems: the heart, the blood, and the vasculature. This thesis describes the implementation of a three-dimensional imaging technique, optical projection tomography (OPT), in conjunction with a computer-based registration algorithm to statistically analyze developmental differences in groups of wild-type mouse embryos. Embryos that differ by only a few hours' gestational time are shown to have developmental differences in blood vessel formation and heart development progression that can be discerned. This thesis describes how we analyzed mouse models of cardiovascular perturbation by OPT to detect morphological differences in embryonic development in both qualitative and quantitative ways. Both a blood vessel specific mutation and a cardiac specific mutation were analyzed, providing evidence that developmental defects of these types can be quantified. Finally, we describe the implementation of OPT imaging to identify statistically significant phenotypes from three different mouse models of cardiovascular perturbation across a range of developmental time points. Image registration methods, combined with intensity- and deformation-based analyses are described and utilized to fully characterize myosin light chain 2a (Mlc2a), delta-like ligand 4 (Dll4), and Endoglin (Eng) mutant mouse embryos. We show that Eng mutant embryos are statistically similar to the Mlc2a phenotype, confirming that these mouse mutants suffer from a primary cardiac developmental defect. Thus, a loss of hemodynamic force caused by defective pumping of the heart is the primary developmental defect affecting these mice.

Developmental Testing of Electric Thrust Vector Control Systems for Manned Launch Vehicle Applications

NASA Technical Reports Server (NTRS)

Bates, Lisa B.; Young, David T.

2012-01-01

This paper describes recent developmental testing to verify the integration of a developmental electromechanical actuator (EMA) with high rate lithium ion batteries and a cross platform extensible controller. Testing was performed at the Thrust Vector Control Research, Development and Qualification Laboratory at the NASA George C. Marshall Space Flight Center. Electric Thrust Vector Control (ETVC) systems like the EMA may significantly reduce recurring launch costs and complexity compared to heritage systems. Electric actuator mechanisms and control requirements across dissimilar platforms are also discussed with a focus on the similarities leveraged and differences overcome by the cross platform extensible common controller architecture.

Small-molecule histone methyltransferase inhibitors display rapid antimalarial activity against all blood stage forms in Plasmodium falciparum

PubMed Central

Malmquist, Nicholas A.; Moss, Thomas A.; Mecheri, Salah; Scherf, Artur; Fuchter, Matthew J.

2012-01-01

Epigenetic factors such as histone methylation control the developmental progression of malaria parasites during the complex life cycle in the human host. We investigated Plasmodium falciparum histone lysine methyltransferases as a potential target class for the development of novel antimalarials. We synthesized a compound library based upon a known specific inhibitor (BIX-01294) of the human G9a histone methyltransferase. Two compounds, BIX-01294 and its derivative TM2-115, inhibited P. falciparum 3D7 parasites in culture with IC50 values of ∼100 nM, values at least 22-fold more potent than their apparent IC50 toward two human cell lines and one mouse cell line. These compounds irreversibly arrested parasite growth at all stages of the intraerythrocytic life cycle. Decrease in parasite viability (>40%) was seen after a 3-h incubation with 1 µM BIX-01294 and resulted in complete parasite killing after a 12-h incubation. Additionally, mice with patent Plasmodium berghei ANKA strain infection treated with a single dose (40 mg/kg) of TM2-115 had 18-fold reduced parasitemia the following day. Importantly, treatment of P. falciparum parasites in culture with BIX-01294 or TM2-115 resulted in significant reductions in histone H3K4me3 levels in a concentration-dependent and exposure time-dependent manner. Together, these results suggest that BIX-01294 and TM2-115 inhibit malaria parasite histone methyltransferases, resulting in rapid and irreversible parasite death. Our data position histone lysine methyltransferases as a previously unrecognized target class, and BIX-01294 as a promising lead compound, in a presently unexploited avenue for antimalarial drug discovery targeting multiple life-cycle stages. PMID:23011794

Developmental and Cell Cycle Quiescence Is Mediated by the Nuclear Hormone Receptor Coregulator DIN-1S in the Caenorhabditis elegans Dauer Larva.

PubMed

Colella, Eileen; Li, Shaolin; Roy, Richard

2016-08-01

When faced with suboptimal growth conditions, Caenorhabditis elegans larvae can enter a diapause-like stage called "dauer" that is specialized for dispersal and survival. The decision to form a dauer larva is controlled by three parallel signaling pathways, whereby a compromise of TGFβ, cyclic guanosine monophosphate, or insulin/IGF-like signaling (ILS) results in dauer formation. Signals from these pathways converge on DAF-12, a nuclear hormone receptor that triggers the changes required to initiate dauer formation. DAF-12 is related to the vitamin D, liver-X, and androstane receptors, and like these human receptors, it responds to lipophilic hormone ligands. When bound to its ligand, DAF-12 acquires transcriptional activity that directs reproductive development, while unliganded DAF-12 forms a dauer-specifying complex with its interacting protein DIN-1S to regulate the transcription of genes required for dauer development. We report here that din-1S is required in parallel to par-4/LKB1 signaling within the gonad to establish cell cycle quiescence during the onset of the dauer stage. We show that din-1S is important for postdauer reproduction when ILS is impaired and is necessary for long-term dauer survival in response to reduced ILS. Our work uncovers several previously uncharacterized functions of DIN-1S in executing and maintaining many of the cellular and physiological processes required for appropriate dauer arrest, while also shedding light on the coordination of nuclear hormone signaling, the LKB1/AMPK signaling cascade, and ILS/TGFβ in the control of cell cycle quiescence and tissue growth: a key feature that is often misregulated in a number of hormone-dependent cancers. Copyright © 2016 by the Genetics Society of America.

Changes in CO2 during Ocean Anoxic Event 1d indicate similarities to other carbon cycle perturbations

NASA Astrophysics Data System (ADS)

Richey, Jon D.; Upchurch, Garland R.; Montañez, Isabel P.; Lomax, Barry H.; Suarez, Marina B.; Crout, Neil M. J.; Joeckel, R. M.; Ludvigson, Greg A.; Smith, Jon J.

2018-06-01

Past greenhouse intervals of the Mesozoic were repeatedly punctuated by Ocean Anoxic Events (OAEs), major perturbations to the global carbon cycle and abrupt climate changes that may serve as relevant analogs for Earth's greenhouse gas-forced climate future. The key to better understanding these transient climate disruptions and possible CO2-forced tipping-points resides in high-resolution, precise, and accurate estimates of atmospheric CO2 for individual OAEs. Here we present a high-temporal resolution, multi-proxy pCO2 reconstruction for the onset of mid-Cretaceous (Albian-Cenomanian Boundary) OAE1d. Coupling of pCO2 estimates with carbon isotopic compositions (δ13C) of charcoal, vitrain, and cuticle from the Rose Creek Pit (RCP), Nebraska, reveals complex phasing, including a lag between the well-documented negative δ13C excursion defining the onset of OAE1d and the CO2 increase. This lag indicates that increased CO2 or other C-based greenhouse gases may not have been the primary cause of the negative excursion. Our study reveals a pCO2 increase within the interval of the negative δ13C excursion, reaching a maximum of up to ∼840 ppm (95% confidence interval -307 ppm/+167 ppm) toward its end. The reconstructed magnitude of CO2 increase (∼357 ppm) is similar to that of Late Cretaceous OAE2 but of smaller magnitude than that of other major carbon cycle perturbations of the Mesozoic assessed via stomatal methods (e.g., the Toarcian OAE [TOAE], Triassic-Jurassic boundary event, Cretaceous-Paleogene Boundary event). Furthermore, our results indicate a possible shared causal or developmental mechanism with OAE1a and the TOAE.

Uncoupling of oxidative phosphorylation prevents the urinary alcohol level cycling caused by feeding ethanol continuously at a constant rate.

PubMed

Li, J; French, B A; Nan, L; Fu, P; French, S W

2005-06-01

The mechanism of the UAL cycle in the intragastric feeding model of alcoholic liver disease in the rat was investigated by administering dinitrophenol (DNP) with ethanol in the diet. The question was: is the rate of oxidative phosphorylation fluxuation essential for the cycle to occur? The question has been partially answered by showing that rotenone, which inhibits complex I, blocks the cycle by preventing the generation of NAD from NADH. This would inhibit ATP generation from complex I but would not affect oxidative phosphorylation by complex 2 and 3. Since the rate of O2 consumption is normal at the troughs of the cycle and decreases at the peaks of the cycle and the levels of ATP are reduced at the peaks of the cycle, it is likely that the rate of oxidative phosphorylation also cycles. Since 2-4 dinitrophenol (DNP) uncouples oxidative phosphorylation, it was anticipated that feeding it with ethanol would prevent the cycle from occurring. This proved to be the case. In addition, DNP caused energy wasting and prevented the increase in serum alanine aminotranspeptidase caused by ethanol feeding, probably by preventing the hypoxia which occurs at the peaks of the cycle.

A Gestational High Protein Diet Affects the Abundance of Muscle Transcripts Related to Cell Cycle Regulation throughout Development in Porcine Progeny

PubMed Central

Oster, Michael; Murani, Eduard; Metges, Cornelia C.; Ponsuksili, Siriluck; Wimmers, Klaus

2012-01-01

Background In various animal models pregnancy diets have been shown to affect offspring phenotype. Indeed, the underlying programming of development is associated with modulations in birth weight, body composition, and continual diet-dependent modifications of offspring metabolism until adulthood, producing the hypothesis that the offspring's transcriptome is permanently altered depending on maternal diet. Methodology/Principal Findings To assess alterations of the offspring's transcriptome due to gestational protein supply, German Landrace sows were fed isoenergetic diets containing protein levels of either 30% (high protein - HP) or 12% (adequate protein - AP) throughout their pregnancy. Offspring muscle tissue (M. longissimus dorsi) was collected at 94 days post conception (dpc), and 1, 28, and 188 days post natum (dpn) for use with Affymetrix GeneChip Porcine Genome Arrays and subsequent statistical and Ingenuity pathway analyses. Numerous transcripts were found to have altered abundance at 94 dpc and 1 dpn; at 28 dpn no transcripts were altered, and at 188 dpn only a few transcripts showed a different abundance between diet groups. However, when assessing transcriptional changes across developmental time points, marked differences were obvious among the dietary groups. Depending on the gestational dietary exposure, short- and long-term effects were observed for mRNA expression of genes related to cell cycle regulation, energy metabolism, growth factor signaling pathways, and nucleic acid metabolism. In particular, the abundance of transcripts related to cell cycle remained divergent among the groups during development. Conclusion Expression analysis indicates that maternal protein supply induced programming of the offspring's genome; early postnatal compensation of the slight growth retardation obvious at birth in HP piglets resulted, as did a permanently different developmental alteration and responsiveness to the common environment of the transcriptome. The transcriptome modulations are interpreted as the molecular equivalent of developmental plasticity of the offspring that necessitates adaptation and maintenance of the organismal phenotype. PMID:22496824

Evidence for the Existence of One Antenna-Associated, Lipid-Dissolved and Two Protein-Bound Pools of Diadinoxanthin Cycle Pigments in Diatoms[C][W

PubMed Central

Lepetit, Bernard; Volke, Daniela; Gilbert, Matthias; Wilhelm, Christian; Goss, Reimund

2010-01-01

We studied the localization of diadinoxanthin cycle pigments in the diatoms Cyclotella meneghiniana and Phaeodactylum tricornutum. Isolation of pigment protein complexes revealed that the majority of high-light-synthesized diadinoxanthin and diatoxanthin is associated with the fucoxanthin chlorophyll protein (FCP) complexes. The characterization of intact cells, thylakoid membranes, and pigment protein complexes by absorption and low-temperature fluorescence spectroscopy showed that the FCPs contain certain amounts of protein-bound diadinoxanthin cycle pigments, which are not significantly different in high-light and low-light cultures. The largest part of high-light-formed diadinoxanthin cycle pigments, however, is not bound to antenna apoproteins but located in a lipid shield around the FCPs, which is copurified with the complexes. This lipid shield is primarily composed of the thylakoid membrane lipid monogalactosyldiacylglycerol. We also show that the photosystem I (PSI) fraction contains a tightly connected FCP complex that is enriched in protein-bound diadinoxanthin cycle pigments. The peripheral FCP and the FCP associated with PSI are composed of different apoproteins. Tandem mass spectrometry analysis revealed that the peripheral FCP is composed mainly of the light-harvesting complex protein Lhcf and also significant amounts of Lhcr. The PSI fraction, on the other hand, shows an enrichment of Lhcr proteins, which are thus responsible for the diadinoxanthin cycle pigment binding. The existence of lipid-dissolved and protein-bound diadinoxanthin cycle pigments in the peripheral antenna and in PSI is discussed with respect to different specific functions of the xanthophylls. PMID:20935178

Blastocyst transfer does not improve cycle outcome as compared to D3 transfer in antagonist cycles with an elevated progesterone level on the day of hCG.

PubMed

Demirel, Cem; Aydoğdu, Serkan; Özdemir, Arzu İlknur; Keskin, Gülşah; Baştu, Ercan; Buyru, Faruk

2017-09-01

To evaluate the association between progesterone elevation on the day of human chorionic gonadotropin (hCG) administration and clinical pregnancy rates of gonadotropin-releasing hormone (GnRH) antagonist in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles with the transfer of embryos at different developmental stages (day-3 versus day-5 ETs). This is a retrospective analysis of fresh IVF/ICSI; 194 cycles out of 2676 conducted in a single center. A total of 2676 cycles were analyzed, of which 386 had no progesterone measurements available. Two hundred eighteen cycles had progesterone elevation (p>1.5 ng/mL) giving an overall incidence of 9.5%. Twenty-four cycles were excluded from further analysis. Of the remaining 194 cycles, 151 had day-3 transfers and 43 had blastocyst transfers. There was no statistically significant difference in pregnancy and clinical pregnancy rates per transfer between the D3-ET and D5-ET groups (46% vs. 49%, and 39% vs. 35%, respectively). The results of this study suggest that blastocyst transfer does not improve cycle outcomes compared with D3 transfer in GnRH antagonist cycles with an elevated progesterone level on the day of hCG.

Integrated Disinfection By-Products Research: Assessing Reproductive and Developmental Risks Posed by Complex Disinfection By-Product Mixtures

EPA Science Inventory

This article presents a toxicologically-based risk assessment strategy for identifying the individual components or fractions of a complex mixture that are associated with its toxicity. The strategy relies on conventional component-based mixtures risk approaches such as dose addi...

The Developmental Effects Of A Municipal Wastewater Effluent On The Northern Leopard Frog, Rana pipiens

EPA Science Inventory

Wastewater effluents are complex mixtures containing a variety of anthropogenic compounds, many of which are known endocrine disruptors. In order to characterize the development and behavorial effects of such a complex mixture, northern leopard frogs, Rana pipiens, were e...

THE POWER TO DETECT A DIFFERENCE: DETERMINING SAMPLE SIZE REQUIREMENTS FOR EVALUATION OF REPRODUCTIVE/DEVELOPMENTAL EFFECTS FROM EXPOSURE TO COMPLEX MIXTURES OF DISINFECTION BYPRODUCTS

EPA Science Inventory

Toxicological assessment of environmentally-realistic complex mixtures of drinking-water disinfection byproducts (DBPs) are needed to address concerns raised by some epidemiological studies showing associations between exposure to chemically disinfected water and adverse reproduc...

From genotype to phenotype: unraveling the complexities of cold adaptation in forest trees

Treesearch

Glenn T. Howe; Sally N. Aitken; David B. Neale; Kathleen D. Jermstad; Nicholas C. Wheeler; Tony H.H Chen

2003-01-01

Adaptation to winter cold in temperate and boreal trees involves complex genetic, physiological, and developmental processes. Genecological studies demonstrate the existence of steep genetic clines for cold adaptation traits in relation to environmental (mostly temperature related) gradients. Population differentiation is generally stronger for cold adaptation traits...

Effects of an iPad-Based Early Reading Intervention with Students with Complex Needs

ERIC Educational Resources Information Center

Lucas, Kristin Goodwin

2015-01-01

Early reading literacy is foundational to all other academic learning. It is imperative that elementary students with and without disabilities be provided with evidence-based reading instruction. Elementary students with developmental disabilities (DD) and complex communication needs (CCN) benefit from evidence-based reading instruction that…

Economic Analysis of Complex Nuclear Fuel Cycles with NE-COST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganda, Francesco; Dixon, Brent; Hoffman, Edward

The purpose of this work is to present a new methodology, and associated computational tools, developed within the U.S. Department of Energy (U.S. DOE) Fuel Cycle Option Campaign to quantify the economic performance of complex nuclear fuel cycles. The levelized electricity cost at the busbar is generally chosen to quantify and compare the economic performance of different baseload generating technologies, including of nuclear: it is the cost of electricity which renders the risk-adjusted discounted net present value of the investment cash flow equal to zero. The work presented here is focused on the calculation of the levelized cost of electricitymore » of fuel cycles at mass balance equilibrium, which is termed LCAE (Levelized Cost of Electricity at Equilibrium). To alleviate the computational issues associated with the calculation of the LCAE for complex fuel cycles, a novel approach has been developed, which has been called the “island approach” because of its logical structure: a generic complex fuel cycle is subdivided into subsets of fuel cycle facilities, called islands, each containing one and only one type of reactor or blanket and an arbitrary number of fuel cycle facilities. A nuclear economic software tool, NE-COST, written in the commercial programming software MATLAB®, has been developed to calculate the LCAE of complex fuel cycles with the “island” computational approach. NE-COST has also been developed with the capability to handle uncertainty: the input parameters (both unit costs and fuel cycle characteristics) can have uncertainty distributions associated with them, and the output can be computed in terms of probability density functions of the LCAE. In this paper NE-COST will be used to quantify, as examples, the economic performance of (1) current Light Water Reactors (LWR) once-through systems; (2) continuous plutonium recycling in Fast Reactors (FR) with driver and blanket; (3) Recycling of plutonium bred in FR into LWR. For each fuel cycle, the contributions to the total LCAE of the main cost components will be identified.« less

Isolation and Compositional Analysis of a CP12-Associated Complex of Calvin Cycle Enzymes from Nicotiana tabacum

USDA-ARS?s Scientific Manuscript database

CP12 is a small intrinsically unstructured protein that forms a multiprotein complex with two Calvin Cycle enzymes, phosphoribulokinase (PRK) and NAD(P)-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The complex can be reconstituted in vitro from recombinant proteins under conditions t...

Developmental sources of conservation and variation in the evolution of the primate eye.

PubMed

Dyer, Michael A; Martins, Rodrigo; da Silva Filho, Manoel; Muniz, José Augusto P C; Silveira, Luiz Carlos L; Cepko, Constance L; Finlay, Barbara L

2009-06-02

Conserved developmental programs, such as the order of neurogenesis in the mammalian eye, suggest the presence of useful features for evolutionary stability and variability. The owl monkey, Aotus azarae, has developed a fully nocturnal retina in recent evolution. Description and quantification of cell cycle kinetics show that embryonic cytogenesis is extended in Aotus compared with the diurnal New World monkey Cebus apella. Combined with the conserved mammalian pattern of retinal cell specification, this single change in retinal progenitor cell proliferation can produce the multiple alterations of the nocturnal retina, including coordinated reduction in cone and ganglion cell numbers, increase in rod and rod bipolar numbers, and potentially loss of the fovea.

Life cycles, fitness decoupling and the evolution of multicellularity.

PubMed

Hammerschmidt, Katrin; Rose, Caroline J; Kerr, Benjamin; Rainey, Paul B

2014-11-06

Cooperation is central to the emergence of multicellular life; however, the means by which the earliest collectives (groups of cells) maintained integrity in the face of destructive cheating types is unclear. One idea posits cheats as a primitive germ line in a life cycle that facilitates collective reproduction. Here we describe an experiment in which simple cooperating lineages of bacteria were propagated under a selective regime that rewarded collective-level persistence. Collectives reproduced via life cycles that either embraced, or purged, cheating types. When embraced, the life cycle alternated between phenotypic states. Selection fostered inception of a developmental switch that underpinned the emergence of collectives whose fitness, during the course of evolution, became decoupled from the fitness of constituent cells. Such development and decoupling did not occur when groups reproduced via a cheat-purging regime. Our findings capture key events in the evolution of Darwinian individuality during the transition from single cells to multicellularity.

Comparative proteomics of two life cycle stages of stable isotope-labeled Trypanosoma brucei reveals novel components of the parasite's host adaptation machinery.

PubMed

Butter, Falk; Bucerius, Ferdinand; Michel, Margaux; Cicova, Zdenka; Mann, Matthias; Janzen, Christian J

2013-01-01

Trypanosoma brucei developed a sophisticated life cycle to adapt to different host environments. Although developmental differentiation of T. brucei has been the topic of intensive research for decades, the mechanisms responsible for adaptation to different host environments are not well understood. We developed stable isotope labeling by amino acids in cell culture in trypanosomes to compare the proteomes of two different life cycle stages. Quantitative comparison of 4364 protein groups identified many proteins previously not known to be stage-specifically expressed. The identification of stage-specific proteins helps to understand how parasites adapt to different hosts and provides new insights into differences in metabolism, gene regulation, and cell architecture. A DEAD-box RNA helicase, which is highly up-regulated in the bloodstream form of this parasite and which is essential for viability and proper cell cycle progression in this stage is described as an example.

Knowledge cannot explain the developmental growth of working memory capacity.

PubMed

Cowan, Nelson; Ricker, Timothy J; Clark, Katherine M; Hinrichs, Garrett A; Glass, Bret A

2015-01-01

According to some views of cognitive growth, the development of working memory capacity can account for increases in the complexity of cognition. It has been difficult to ascertain, though, that there actually is developmental growth in capacity that cannot be attributed to other developing factors. Here we assess the role of item familiarity. We document developmental increases in working memory for visual arrays of English letters versus unfamiliar characters. Although letter knowledge played a special role in development between the ages of 6 and 8 years, children with adequate letter knowledge showed practically the same developmental growth in normalized functions for letters and unfamiliar characters. The results contribute to a growing body of evidence that the developmental improvement in working memory does not wholly stem from supporting processes such as encoding, mnemonic strategies, and knowledge. A video abstract is available at: https://www.youtube.com/watch?v=LJdqErLR2Hs&feature=youtu.be. © 2014 John Wiley & Sons Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garige, Mamatha; Walters, Eric, E-mail: ewalters@howard.edu

The molecular basis for nutraceutical properties of the polyphenol curcumin (Curcuma longa, Turmeric) is complex, affecting multiple factors that regulate cell signaling and homeostasis. Here, we report the effect of curcumin on cellular and developmental mechanisms in the eukaryotic model, Dictyostelium discoideum. Dictyostelium proliferation was inhibited in the presence of curcumin, which also suppressed the prestarvation marker, discoidin I, members of the yakA-mediated developmental signaling pathway, and expression of the extracellular matrix/cell adhesion proteins (DdCAD and csA). This resulted in delayed chemotaxis, adhesion, and development of the organism. In contrast to the inhibitory effects on developmental genes, curcumin induced gstAmore » gene expression, overall GST activity, and generated production of reactive oxygen species. These studies expand our knowledge of developmental and biochemical signaling influenced by curcumin, and lends greater consideration of GST enzyme function in eukaryotic cell signaling, development, and differentiation.« less

A developmental approach to mentalizing communities: I. A model for social change.

PubMed

Twemlow, Stuart W; Fonagy, Peter; Sacco, Frank C

2005-01-01

A developmental model is proposed applying attachment theory to complex social systems to promote social change. The idea of mentalizing communities is outlined with a proposal for three projects testing the model: ways to reduce bullying and create a peaceful climate in schools, projects to promote compassion in cities by a focus of end-of-life care, and a mentalization-based intervention into parenting style of borderline and substance abusing parents.

Common developmental pathways link tooth shape to regeneration

PubMed Central

Fraser, Gareth J.; Bloomquist, Ryan F.; Streelman, J. Todd

2013-01-01

In many non-mammalian vertebrates, adult dentitions result from cyclical rounds of tooth regeneration wherein simple unicuspid teeth are replaced by more complex forms. Therefore and by contrast to mammalian models, the numerical majority of vertebrate teeth develop shape during the process of replacement. Here, we exploit the dental diversity of Lake Malawi cichlid fishes to ask how vertebrates generally replace their dentition and in turn how this process acts to influence resulting tooth morphologies. First, we used immunohistochemistry to chart organogenesis of continually replacing cichlid teeth and discovered an epithelial down-growth that initiates the replacement cycle via a labial proliferation bias. Next, we identified sets of co-expressed genes from common pathways active during de novo, lifelong tooth replacement and tooth morphogenesis. Of note, we found two distinct epithelial cell populations, expressing markers of dental competence and cell potency, which may be responsible for tooth regeneration. Related gene sets were simultaneously active in putative signaling centers associated with the differentiation of replacement teeth with complex shapes. Finally, we manipulated targeted pathways (BMP, FGF, Hh, Notch, Wnt/β-catenin) in vivo with small molecules and demonstrated dose-dependent effects on both tooth replacement and tooth shape. Our data suggest that the processes of tooth regeneration and tooth shape morphogenesis are integrated via a common set of molecular signals. This linkage has subsequently been lost or decoupled in mammalian dentitions where complex tooth shapes develop in first generation dentitions that lack the capacity for lifelong replacement. Our dissection of the molecular mechanics of vertebrate tooth replacement coupled to complex shape pinpoints aspects of odontogenesis that might be re-evolved in the lab to solve problems in regenerative dentistry. PMID:23422830

Dosage-Sensitive Function of RETINOBLASTOMA RELATED and Convergent Epigenetic Control Are Required during the Arabidopsis Life Cycle

PubMed Central

Johnston, Amal J.; Kirioukhova, Olga; Barrell, Philippa J.; Rutten, Twan; Moore, James M.; Baskar, Ramamurthy; Grossniklaus, Ueli; Gruissem, Wilhelm

2010-01-01

The plant life cycle alternates between two distinct multi-cellular generations, the reduced gametophytes and the dominant sporophyte. Little is known about how generation-specific cell fate, differentiation, and development are controlled by the core regulators of the cell cycle. In Arabidopsis, RETINOBLASTOMA RELATED (RBR), an evolutionarily ancient cell cycle regulator, controls cell proliferation, differentiation, and regulation of a subset of Polycomb Repressive Complex 2 (PRC2) genes and METHYLTRANSFERASE 1 (MET1) in the male and female gametophytes, as well as cell fate establishment in the male gametophyte. Here we demonstrate that RBR is also essential for cell fate determination in the female gametophyte, as revealed by loss of cell-specific marker expression in all the gametophytic cells that lack RBR. Maintenance of genome integrity also requires RBR, because diploid plants heterozygous for rbr (rbr/RBR) produce an abnormal portion of triploid offspring, likely due to gametic genome duplication. While the sporophyte of the diploid mutant plants phenocopied wild type due to the haplosufficiency of RBR, genetic analysis of tetraploid plants triplex for rbr (rbr/rbr/rbr/RBR) revealed that RBR has a dosage-dependent pleiotropic effect on sporophytic development, trichome differentiation, and regulation of PRC2 subunit genes CURLY LEAF (CLF) and VERNALIZATION 2 (VRN2), and MET1 in leaves. There were, however, no obvious cell cycle and cell proliferation defects in these plant tissues, suggesting that a single functional RBR copy in tetraploids is capable of maintaining normal cell division but is not sufficient for distinct differentiation and developmental processes. Conversely, in leaves of mutants in sporophytic PRC2 subunits, trichome differentiation was also affected and expression of RBR and MET1 was reduced, providing evidence for a RBR-PRC2-MET1 regulatory feedback loop involved in sporophyte development. Together, dosage-sensitive RBR function and its genetic interaction with PRC2 genes and MET1 must have been recruited during plant evolution to control distinct generation-specific cell fate, differentiation, and development. PMID:20585548

Reproductive and developmental costs of deltamethrin resistance in the Chagas disease vector Triatoma infestans.

PubMed

Germano, Mónica Daniela; Inés Picollo, María

2015-06-01

Effective chemical control relies on reducing vector population size. However, insecticide selection pressure is often associated with the development of resistant populations that reduce control success. In treated areas, these resistant individuals present an adaptive advantage due to enhanced survival. Resistance can also lead to negative effects when the insecticide pressure ceases. In this study, the biological effects of deltamethrin resistance were assessed in the Chagas disease vector Triatoma infestans. The length of each developmental stage and complete life cycle, mating rate, and fecundity were evaluated. Susceptible and resistant insects presented similar mating rates. A reproductive cost of resistance was expressed as a lower fecundity in the resistant colony. Developmental costs in the resistant colony were in the form of a shortening of the second and third nymph stage duration and an extension of the fifth stage. A maternal effect of deltamethrin resistance is suggested as these effects were identified in resistant females and their progeny independently of the mated male's deltamethrin response. Our results suggest the presence of pleiotropic effects of deltamethrin resistance. Possible associations of these characters to other traits such as developmental delays and behavioral resistance are discussed. © 2015 The Society for Vector Ecology.

Green Algae and the Origins of Multicellularity in the Plant Kingdom

PubMed Central

Umen, James G.

2014-01-01

The green lineage of chlorophyte algae and streptophytes form a large and diverse clade with multiple independent transitions to produce multicellular and/or macroscopically complex organization. In this review, I focus on two of the best-studied multicellular groups of green algae: charophytes and volvocines. Charophyte algae are the closest relatives of land plants and encompass the transition from unicellularity to simple multicellularity. Many of the innovations present in land plants have their roots in the cell and developmental biology of charophyte algae. Volvocine algae evolved an independent route to multicellularity that is captured by a graded series of increasing cell-type specialization and developmental complexity. The study of volvocine algae has provided unprecedented insights into the innovations required to achieve multicellularity. PMID:25324214

Nonlinear Growth Curves in Developmental Research

PubMed Central

Grimm, Kevin J.; Ram, Nilam; Hamagami, Fumiaki

2011-01-01

Developmentalists are often interested in understanding change processes and growth models are the most common analytic tool for examining such processes. Nonlinear growth curves are especially valuable to developmentalists because the defining characteristics of the growth process such as initial levels, rates of change during growth spurts, and asymptotic levels can be estimated. A variety of growth models are described beginning with the linear growth model and moving to nonlinear models of varying complexity. A detailed discussion of nonlinear models is provided, highlighting the added insights into complex developmental processes associated with their use. A collection of growth models are fit to repeated measures of height from participants of the Berkeley Growth and Guidance Studies from early childhood through adulthood. PMID:21824131

Complex Autocatalysis in Simple Chemistries.

PubMed

Virgo, Nathaniel; Ikegami, Takashi; McGregor, Simon

2016-01-01

Life on Earth must originally have arisen from abiotic chemistry. Since the details of this chemistry are unknown, we wish to understand, in general, which types of chemistry can lead to complex, lifelike behavior. Here we show that even very simple chemistries in the thermodynamically reversible regime can self-organize to form complex autocatalytic cycles, with the catalytic effects emerging from the network structure. We demonstrate this with a very simple but thermodynamically reasonable artificial chemistry model. By suppressing the direct reaction from reactants to products, we obtain the simplest kind of autocatalytic cycle, resulting in exponential growth. When these simple first-order cycles are prevented from forming, the system achieves superexponential growth through more complex, higher-order autocatalytic cycles. This leads to nonlinear phenomena such as oscillations and bistability, the latter of which is of particular interest regarding the origins of life.

Stage-dependent piRNAs in chicken implicated roles in modulating male germ cell development.

PubMed

Chang, Kai-Wei; Tseng, Yen-Tzu; Chen, Yi-Chen; Yu, Chih-Yun; Liao, Hung-Fu; Chen, Yi-Chun; Tu, Yu-Fan Evan; Wu, Shinn-Chih; Liu, I-Hsuan; Pinskaya, Marina; Morillon, Antonin; Pain, Bertrand; Lin, Shau-Ping

2018-06-01

The PIWI/piRNA pathway is a conserved machinery important for germ cell development and fertility. This piRNA-guided molecular machinery is best known for repressing derepressed transposable elements (TE) during epigenomic reprogramming. The extent to which piRNAs are involved in modulating transcripts beyond TEs still need to be clarified, and it may be a stage-dependent event. We chose chicken germline as a study model because of the significantly lower TE complexity in the chicken genome compared to mammalian species. We generated high-confidence piRNA candidates in various stages across chicken germline development by 3'-end-methylation-enriched small RNA sequencing and in-house bioinformatics analysis. We observed a significant developmental stage-dependent loss of TE association and a shifting of the ping-pong cycle signatures. Moreover, the stage-dependent reciprocal abundance of LINE retrotransposons, CR1-C, and its associated piRNAs implicated the developmental stage-dependent role of piRNA machinery. The stage dependency of piRNA expression and its potential functions can be better addressed by analyzing the piRNA precursors/clusters. Interestingly, the new piRNA clusters identified from embryonic chicken testes revealed evolutionary conservation between chickens and mammals, which was previously thought to not exist. In this report, we provided an original chicken RNA resource and proposed an analytical methodology that can be used to investigate stage-dependent changes in piRNA compositions and their potential roles in TE regulation and beyond, and also revealed possible conserved functions of piRNAs in developing germ cells.

Developmental competence of Dromedary camel (Camelus dromedarius) oocytes selected using brilliant cresyl blue staining.

PubMed

Fathi, Mohamed; Ashry, Mohamed; Salama, Ali; Badr, Magdy R

2017-08-01

The objectives of the present studies were to investigate the developmental capacity of dromedary camel oocytes selected by brilliant cresyl blue (BCB) staining and to investigate the expression of select transcripts in germinal vesicle (GV) stage oocytes. These transcripts included BMP15 and GDF9 as important transcripts for folliculogenesis and oocyte development, Zar1 and Mater as maternal transcripts required for embryonic development, Cyclin B1 and CDK1 as cell cycle regulators and Oct4 and STAT3 as transcription factors. Dromedary camel oocytes were retrieved from ovaries collected at a local slaughterhouse. After exposure to BCB staining, cumulus-oocyte complexes (COCs) from BCB+, BCB- and control (selected based on morphological criteria) groups were subjected to in vitro maturation, in vitro fertilization and in vitro culture. For gene expression studies, after BCB staining cumulus cells were stripped off and the completely denuded GV stage oocytes were used for RT-PCR analysis of selected transcripts. BCB+ oocytes showed higher maturation, and fertilization rates compared with BCB- and control groups. Indices of early embryonic development, namely, cleavage at 48 hours post insemination (hpi), and development to morula at day 5 and day 7 blastocyst rates were also significantly higher in the BCB+ group. RT-PCR revealed a higher expression of BMP15, GDF9, Zar1, Mater, Cyclin B1, CDK1, OCT4 and STAT3 in good quality oocytes that stained positively for BCB (BCB+). Collectively, results provide novel information about the use of BCB screening for selecting good quality oocytes to improve in vitro embryo production in the dromedary camel.

Transcriptome analysis of sika deer in China.

PubMed

Jia, Bo-Yin; Ba, Heng-Xing; Wang, Gui-Wu; Yang, Ying; Cui, Xue-Zhe; Peng, Ying-Hua; Zheng, Jun-Jun; Xing, Xiu-Mei; Yang, Fu-He

2016-10-01

Sika deer is of great commercial value because their antlers are used in tonics and alternative medicine and their meat is healthy and delicious. The goal of this study was to generate transcript sequences from sika deer for functional genomic analyses and to identify the transcripts that demonstrate tissue-specific, age-dependent differential expression patterns. These sequences could enhance our understanding of the molecular mechanisms underlying sika deer growth and development. In the present study, we performed de novo transcriptome assembly and profiling analysis across ten tissue types and four developmental stages (juvenile, adolescent, adult, and aged) of sika deer, using Illumina paired-end tag (PET) sequencing technology. A total of 1,752,253 contigs with an average length of 799 bp were generated, from which 1,348,618 unigenes with an average length of 590 bp were defined. Approximately 33.2 % of these (447,931 unigenes) were then annotated in public protein databases. Many sika deer tissue-specific, age-dependent unigenes were identified. The testes have the largest number of tissue-enriched unigenes, and some of them were prone to develop new functions for other tissues. Additionally, our transcriptome revealed that the juvenile-adolescent transition was the most complex and important stage of the sika deer life cycle. The present work represents the first multiple tissue transcriptome analysis of sika deer across four developmental stages. The generated data not only provide a functional genomics resource for future biological research on sika deer but also guide the selection and manipulation of genes controlling growth and development.

Carryover effects of predation risk on postembryonic life-history stages in a freshwater shrimp.

PubMed

Ituarte, Romina Belén; Vázquez, María Guadalupe; González-Sagrario, María de los Ángeles; Spivak, Eduardo Daniel

2014-04-01

For organisms with complex life histories it is well known that risk experienced early in life, as embryos or larvae, may have effects throughout the life cycle. Although carryover effects have been well documented in invertebrates with different levels of parental care, there are few examples of predator-induced responses in externally brooded embryos. Here, we studied the effects of nonlethal predation risk throughout the embryonic development of newly spawned eggs carried by female shrimp on the timing of egg hatching, hatchling morphology, larval development and juvenile morphology. We also determined maternal body mass at the end of the embryonic period. Exposure to predation risk cues during embryonic development led to larger larvae which also had longer rostra but reached the juvenile stage sooner, at a smaller size and with shorter rostra. There was no difference in hatching timing, but changes in larval morphology and developmental timing showed that the embryos had perceived waterborne substances indicative of predation risk. In addition to carryover effects on larval and juvenile stages, predation threat provoked a decrease of body mass in mothers exposed to predator cues while brooding. Our results suggest that risk-exposed embryos were able to recognize the same infochemicals as their mothers, manifesting a response in the free-living larval stage. Thus, future studies assessing anti-predator phenotypes should include embryonic development, which seems to determine the morphology and developmental time of subsequent life-history stages according to perceived environmental conditions. Copyright © 2014 Elsevier GmbH. All rights reserved.

The Romantic Relationship Experiences of Young Adult Women Exposed to Domestic Violence.

PubMed

Haselschwerdt, Megan L; Carlson, Camille E; Hlavaty, Kathleen

2018-05-01

Guided by a review of the literature on intergenerational transmission of violence, or "the cycle of violence", and Johnson's typology of domestic violence, the current study qualitatively examined the romantic relationship experiences of 23 young adult women who were exposed to father-mother-perpetrated domestic violence (DV) during childhood and adolescence. Findings are partially consistent with the hypothesis that DV exposure is associated with an increased risk of later experiencing dating violence, such that half of the sample reported having abusive partners or relationships during high school. However, none of the young women reported violence or abuse during the early years of college, suggesting the salience of developmental timing when examining transmission of violence. Beyond whether the women experienced dating violence, they described how their earlier DV exposure experiences influence how they entered into, managed, and exited romantic relationships. By comparing their potential, former, and current romantic relationships with their fathers' violence and abuse, their mothers' victimization, and high school relationship partners' behaviors, the young women actively and strategically managed their relationship involvement over time. Although women exposed to both situational couple and coercive controlling violence reported experiencing abuse during high school, only women with coercive controlling exposure experienced reported having nonabusive, healthy, and supportive relationships. Findings suggest that the romantic relationship experiences of DV-exposed young adult women are complex, warranting a holistic approach that takes into consideration the full range of potential relationship experiences, the role of former relationships, and developmental timing when seeking to prevent and intervene in intergenerational transmission processes.

Gene expression profiles in the cerebellum and hippocampus following exposure to a neurotoxicant, Aroclor 1254: Developmental effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Royland, Joyce E.; Wu, Jinfang; Zawia, Nasser H.

2008-09-01

The developmental consequences of exposure to the polychlorinated biphenyls (PCBs) have been widely studied, making PCBs a unique model to understand issues related to environmental mixture of persistent chemicals. PCB exposure in humans adversely affects neurocognitive development, causes psychomotor difficulties, and contributes to attention deficits in children, all of which seem to be associated with altered patterns of neuronal connectivity. In the present study, we examined gene expression profiles in the rat nervous system following PCB developmental exposure. Pregnant rats (Long-Evans) were dosed perinatally with 0 or 6 mg/kg/day of Aroclor 1254 from gestation day 6 through postnatal day (PND)more » 21. Gene expression in cerebellum and hippocampus from PND7 and PND14 animals was analyzed with an emphasis on developmental aspects. Changes in gene expression ({>=} 1.5 fold) in control animals identified normal developmental changes. These basal levels of expression were compared to data from Aroclor 1254-treated animals to determine the impact of gestational PCB exposure on developmental parameters. The results indicate that the expression of a number of developmental genes related to cell cycle, synaptic function, cell maintenance, and neurogenesis is significantly altered from PND7 to PND14. Aroclor 1254 treatment appears to dampen the overall growth-related gene expression levels in both regions with the effect being more pronounced in the cerebellum. Functional analysis suggests that Aroclor 1254 delays maturation of the developing nervous system, with the consequences dependent on the ontological state of the brain area and the functional role of the individual gene. Such changes may underlie learning and memory deficits observed in PCB exposed animals and humans.« less

A Novel Interaction of Ecdysoneless (ECD) Protein with R2TP Complex Component RUVBL1 Is Required for the Functional Role of ECD in Cell Cycle Progression.

PubMed

Mir, Riyaz A; Bele, Aditya; Mirza, Sameer; Srivastava, Shashank; Olou, Appolinaire A; Ammons, Shalis A; Kim, Jun Hyun; Gurumurthy, Channabasavaiah B; Qiu, Fang; Band, Hamid; Band, Vimla

2015-12-28

Ecdysoneless (ECD) is an evolutionarily conserved protein whose germ line deletion is embryonic lethal. Deletion of Ecd in cells causes cell cycle arrest, which is rescued by exogenous ECD, demonstrating a requirement of ECD for normal mammalian cell cycle progression. However, the exact mechanism by which ECD regulates cell cycle is unknown. Here, we demonstrate that ECD protein levels and subcellular localization are invariant during cell cycle progression, suggesting a potential role of posttranslational modifications or protein-protein interactions. Since phosphorylated ECD was recently shown to interact with the PIH1D1 adaptor component of the R2TP cochaperone complex, we examined the requirement of ECD phosphorylation in cell cycle progression. Notably, phosphorylation-deficient ECD mutants that failed to bind to PIH1D1 in vitro fully retained the ability to interact with the R2TP complex and yet exhibited a reduced ability to rescue Ecd-deficient cells from cell cycle arrest. Biochemical analyses demonstrated an additional phosphorylation-independent interaction of ECD with the RUVBL1 component of the R2TP complex, and this interaction is essential for ECD's cell cycle progression function. These studies demonstrate that interaction of ECD with RUVBL1, and its CK2-mediated phosphorylation, independent of its interaction with PIH1D1, are important for its cell cycle regulatory function. Copyright © 2016, American Society for Microbiology. All Rights Reserved.