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PubMed2025

Microfluidics to Follow Spatiotemporal Dynamics at the Nucleo-Cytoplasmic Interface During Plant Root Growth.

Nuclear dynamics refers to global/local changes in the molecular and spatial organization of genomic DNA that can occur during development or in response to environmental stress signals and eventually impact genomic functions. In plants, nuclear dynamics relies notably on the connection of the nucleus with the cytoskeleton during development. It orchestrates genomic functions in response to developmental and environmental cues. This is particularly true in the plant root system, which is constantly exposed to a wide range of internal and external stimuli. Currently, studying nuclear dynamics in a growing root is challenging due to limitations regarding real-time imaging for quantitative analyses under controlled conditions. Microfluidic systems for plant cell studies are valuable analytical tools that provide precise control of culture conditions together with live-imaging capabilities at high temporal and spatial resolutions. Herein, we describe a microfluidic platform to unravel dynamically and noninvasively nuclear organization in the seedling root system exposed to various treatments. As exemplified here, our microfluidic platform can be conveniently used for real-time microscopy imaging and quantitative analysis of fine nuclear morphological changes upon modifying cytoskeleton dynamics. Importantly, our system can be applied to a wide variety of microscopic means including high-resolution microscopy to investigate diverse subcellular compartments or nuclear domains in Arabidopsis thaliana roots.

Plant Roots↗
PubMed2006

Dynamic regulation of Drosophila nuclear receptor activity in vivo.

Nuclear receptors are a large family of transcription factors that play major roles in development, metamorphosis, metabolism and disease. To determine how, where and when nuclear receptors are regulated by small chemical ligands and/or protein partners, we have used a 'ligand sensor' system to visualize spatial activity patterns for each of the 18 Drosophila nuclear receptors in live developing animals. Transgenic lines were established that express the ligand binding domain of each nuclear receptor fused to the DNA-binding domain of yeast GAL4. When combined with a GAL4-responsive reporter gene, the fusion proteins show tissue- and stage-specific patterns of activation. We show that these responses accurately reflect the presence of endogenous and exogenously added hormone, and that they can be modulated by nuclear receptor partner proteins. The amnioserosa, yolk, midgut and fat body, which play major roles in lipid storage, metabolism and developmental timing, were identified as frequent sites of nuclear receptor activity. We also see dynamic changes in activation that are indicative of sweeping changes in ligand and/or co-factor production. The screening of a small compound library using this system identified the angular psoralen angelicin and the insect growth regulator fenoxycarb as activators of the Ultraspiracle (USP) ligand-binding domain. These results demonstrate the utility of this system for the functional dissection of nuclear receptor pathways and for the development of new receptor agonists and antagonists that can be used to modulate metabolism and disease and to develop more effective means of insect control.

Animals↗
PubMed1978

Primary and secondard process in the context of cerebral hemispheric specialization.

Increasing knowledge of human cerebral hemispheric specialization suggests a relationship between the different formal modes of thinking attributed to the two hemispheres and those psychoanalysis has traditionally assigned to primary (similar to recessive hemispheric) and secondary (similar to dominant hemispheric) processes. The fact of a lifelong capability at the neurophysiological level for coequal, simultaneous registration and organization of experience in these different cognitive modes allows primary process to be conceptualized in developmental terms. As the first organizing mode of infantile development, it shapes the primitive content of the dynamic unconscious. Thereafter, it can be viewed as coexistent and commingled with secondary process in dynamic tension, complementarity, and developing complexity. Observations from normal behavior, current research, and the functioning of the psychoanalyst support this thesis and reinforce an emerging viewpoint in contemporary psychoanalysis that primary processes are not confined to archaic levels but are open to growth and developmental integration into the complete range of ego functions.

Affect↗
PubMed1999

Developmental changes of cerebral blood flow and oxygen metabolism in children.

BACKGROUND AND PURPOSE: Normal values for cerebral blood flow (CBF) and metabolism in adults are well established, but not for children. Our goal, therefore, was to clarify functional developmental changes of the brain in children in relation to CBF and oxygen metabolism. METHODS: We measured regional CBF (rCBF), regional cerebral metabolic rate for oxygen (rCMRO2), and regional oxygen extraction fraction (rOEF), using positron emission tomography (PET). We performed 30 PET studies in 24 children ages 10 days to 16 years (nine boys, 15 girls), using a steady inhalation method with C(15)O2, (15)O2, and 15CO in order to measure rCBF, rCMRO2, and rOEF, respectively. Regions of interest were set in the primary cerebral areas (sensorimotor, visual, temporal, and parietal cortex), cerebral association areas (frontal and visual association), basal ganglia (lenticular and thalamus), and posterior fossa (brain stem and cerebellar cortex). Subjects were grouped by age (< 1, 1 to < 3, 3 to < 8, and > or = 8 years), and the absolute values of the parameters were compared with those obtained from 10 healthy adults. RESULTS: rCBF and rCMRO2 were lower in the neonatal period than in older children and adults, and increased significantly during early childhood. rCBF was higher as compared with adults, peaking around age 7, whereas rCMRO2 was relatively high, with the last area to increase being the frontal association cortex. Both rCBF and rCMRO2 reached adult values during adolescence. No difference in rCBF was observed between the basal ganglia and the primary cerebral cortex; however, it was prominent in the occipital lobe in every age bracket. No significant changes in rOEF were found during childhood. CONCLUSION: The dynamic changes of rCBF and rCMRO2 observed in children probably reflect the physiologic developmental state within anatomic areas of the brain.

Adolescent↗
PubMed1994

Emotion regulation: a theme in search of definition.

Contemporary interest in emotion regulation promises to advance important new views of emotional development as well as offering applications to developmental psychopathology, but these potential contributions are contingent on developmentalists' attention to some basic definitional issues. This essay offers a perspective on these issues by considering how emotion regulation should be defined, the various components of the management of emotion, how emotion regulation strategies fit into the dynamics of social interaction, and how individual differences in emotion regulation should be conceptualized and measured. In the end, it seems clear that emotion regulation is a conceptual rubric for a remarkable range of developmental processes, each of which may have its own catalysts and control processes. Likewise, individual differences in emotion regulation skills likely have multifaceted origins and are also related in complex ways to the person's emotional goals and the immediate demands of the situation. Assessment approaches that focus on the dynamics of emotion are well suited to elucidating these complex developmental and individual differences. In sum, a challenging research agenda awaits those who enter this promising field of study.

Adaptation, Psychological↗
PubMedDate not supplied

Developmental perspective of sensory organization on postural control.

The development of sensory organization on postural control was studied using computerized dynamic posturography. Generalized postural stability increased with age but had not reached the adult level at the age of 15 years. The significance of each sensory component for postural control was analysed. Somatosensory function developed early and became comparable with the adult level at the age of 3-4 years. The visual function followed and reached the adult level at the age of 15 years. The vestibular function developed later, showing a considerably lower level even at the age of 15 years. Girls were superior to boys with respect to the vestibular function at the age of 7-8 years. The implication of this sexual difference for some developmental disorders is discussed.

Adolescent↗
PubMed2001

Theory of robustness of irreversible differentiation in a stem cell system: chaos hypothesis.

Based on an extensive study of a dynamical systems model of the development of a cell society, a novel theory for stem cell differentiation and its regulation is proposed as the "chaos hypothesis". Two fundamental features of stem cell systems-stochastic differentiation of stem cells and the robustness of a system due to regulation of this differentiation-are found to be general properties of a system of interacting cells exhibiting chaotic intra-cellular reaction dynamics and cell division, whose presence does not depend on the detail of the model. It is found that stem cells differentiate into other cell types stochastically due to a dynamical instability caused by cell-cell interactions, in a manner described by the Isologous Diversification theory. This developmental process is shown to be stable not only with respect to molecular fluctuations but also with respect to the removal of cells. With this developmental process, the irreversible loss of multipotency accompanying the change from a stem cell to a differentiated cell is shown to be characterized by a decrease in the chemical diversity in the cell and of the complexity of the cellular dynamics. The relationship between the division speed and the loss of multipotency is also discussed. Using our model, some predictions that can be tested experimentally are made for a stem cell system.

Animals↗
PubMed2006

Developmental kinetics, turnover, and stimulatory capacity of thymic epithelial cells.

Despite the importance of thymic stromal cells to T-cell development, relatively little is known about their biology. Here, we use single-cell analysis of stromal cells to analyze extensive changes in the number and composition of thymic stroma throughout life, revealing a surprisingly dynamic population. Phenotypic progression of thymic epithelial subsets was assessed at high resolution in young mice to provide a developmental framework. The cellular and molecular requirements of adult epithelium were studied, using various mutant mice to demonstrate new cross talk checkpoints dependent on RelB in the cortex and CD40 in the medulla. With the use of Ki67 and BrdU labeling, the turnover of thymic epithelium was found to be rapid, but then diminished on thymic involution. The various defects in stromal turnover and composition that accompanied involution were rapidly reversed following sex steroid ablation. Unexpectedly, mature cortical and medullary epithelium showed a potent capacity to stimulate naive T cells, comparable to that of thymic dendritic cells. Overall, these studies show that the thymic stroma is a surprisingly dynamic population and may have a more direct role in negative selection than previously thought.

Aging↗
PubMed2006

Multilocus linkage disequilibrium mapping of epistatic quantitative trait loci that regulate HIV dynamics: a simulation approach.

The time-dependent change of HIV particle load, i.e. HIV dynamics, is likely to be controlled by a multitude of quantitative trait loci (QTL) that interact with each other as well as with various developmental and environmental factors in a coordinated manner. In this article, we have derived a new statistical model for mapping the epistatic QTL responsible for HIV dynamics in a natural human population. This model, constructed on the integrated theme of functional mapping and linkage disequilibrium (LD) mapping, can make use of information from multiple markers genotyped from the human genome. It allows for the test and estimation of genetic actions and interactions involved in the control of HIV progression and provides a general platform to identify the detailed genetic architecture of resistance or susceptibility of humans to HIV on a dynamic scale. We have generalized this model to accommodate various complicated clincal designs for AIDS studies. Simulation studies with different scenarios are performed to examine the statistical behaviour of the model. The genetic and statistical extensions of this mapping model to HIV/AIDS genomic research are discussed.

Computer Simulation↗
PubMed2026

CACNA1C Genetic Variants Differentially Affect Neuronal Networks Through Divergent Pathways.

BACKGROUND: CACNA1C encodes the pore-forming subunit of the L-type calcium channel Cav1.2. Common variants in CACNA1C are associated with psychiatric disorders, whereas rare single nucleotide variants cause CACNA1C-related disorder, a multisystem disorder with symptoms that include autism spectrum disorder (ASD), intellectual disability, and seizures. However, the cellular mechanisms linking CACNA1C dysfunction to neurodevelopmental phenotypes remain poorly understood. METHODS: We generated isogenic CACNA1C loss-of-function induced pluripotent stem cell lines and reprogrammed a line from an individual carrying a novel predicted gain-of-function variant (p.Ala1521Pro) in CACNA1C. Neuronal activity was assessed using multielectrode arrays, pharmacological manipulation, and gene expression analysis. Early developmental phenotypes were examined using quantitative reverse transcriptase polymerase chain reaction, immunocytochemistry, and RNA sequencing. RESULTS: Neurons carrying CACNA1C variants displayed opposing alterations in network dynamics, depending on variant type. Pharmacological and molecular assays indicated that these network differences were associated with dysregulated GABAergic (gamma-aminobutyric acidergic) signaling. Early developmental analysis revealed that loss of CACNA1C altered rosette morphology, CREB (cAMP response element binding protein) phosphorylation, and transcriptional programs related to axonogenesis and synaptic signaling, indicating effects on neuronal differentiation. The patient line exhibited opposing effects on rosette morphology and CREB signaling, reflecting variant-specific effects. CONCLUSIONS: These findings demonstrate that Cav1.2 regulates excitatory-inhibitory balance, network organization, and aspects of neurodevelopment. Divergent effects of CACNA1C variants highlight how altered Cav1.2 signaling contributes to variable neurodevelopmental phenotypes, including ASD and epilepsy, and establish a framework for defining CACNA1C variant effects in human neurons.

CACNA1C↗
PubMed2001

Dynamics of meiosis and protein kinase activities in bovine oocytes correlated to prolactin treatment and follicle size.

Oocyte developmental competence depends on the size of the original follicle and is affected by compounds like prolactin. We wished to investigate nuclear and cytoplasmic maturation of bovine oocytes correlated to their origin and response to prolactin treatment, by monitoring at frequent intervals meiotic configuration of chromosomes and activity of histone H1 and MAP-kinase. Bovine ovaries were obtained from a slaughterhouse and oocytes were recovered by follicle isolation. Oocytes (n = 1,397) with a compact cumulus were selected from small (2 to 3 mm) and large (4 to 5 mm in diameter) follicles and cultured up to 28 h in TCM 199+20% bull serum with or without 50 ng/mL bovine prolactin. Four groups of oocytes were formed: originating from small or large follicles, and treated or not treated with prolactin. At the scheduled time intervals for in vitro maturation, cumulus oocyte complexes from the 4 groups were randomly selected and the oocytes were analyzed for histone H1 and MAP-kinase, and for chromatin configuration. The first meiotic division took longer to complete in oocytes from large follicles (P < 0.01). Under the influence of prolactin the meiosis was prolonged in oocytes both from small and large follicles (P < 0.05). Histone H1 and MAP-kinases started to be activated at approximately the same time, around 6 h after beginning maturation. But after this time, significantly lower levels of both kinase activities were found in oocytes treated with prolactin, especially those treated during Meiosis I (P < 0.05). Our results indicate a correlation of chromatin configuration and histone H1/MAP-kinase activities.

Animals↗
PubMed2005

Glutamate receptor dynamics organizing synapse formation in vivo.

Insight into how glutamatergic synapses form in vivo is important for understanding developmental and experience-triggered changes of excitatory circuits. Here, we imaged postsynaptic densities (PSDs) expressing a functional, GFP-tagged glutamate receptor subunit (GluR-IIA(GFP)) at neuromuscular junctions of Drosophila melanogaster larvae for several days in vivo. New PSDs, associated with functional and structural presynaptic markers, formed independently of existing synapses and grew continuously until reaching a stable size within hours. Both in vivo photoactivation and photobleaching experiments showed that extrasynaptic receptors derived from diffuse, cell-wide pools preferentially entered growing PSDs. After entering PSDs, receptors were largely immobilized. In comparison, other postsynaptic proteins tested (PSD-95, NCAM and PAK homologs) exchanged faster and with no apparent preference for growing synapses. We show here that new glutamatergic synapses form de novo and not by partitioning processes from existing synapses, suggesting that the site-specific entry of particular glutamate receptor complexes directly controls the assembly of individual PSDs.

Animals↗
PubMed1997

Towards a novel augmented-reality tool to visualize dynamic 3-D anatomy.

Using augmented reality (AR) to teach dynamic 3-D anatomy may impart better understanding of bone dynamics during body movement. We are currently developing an AR tool that will allow superimposition and registration of bone structures on real anatomical counterparts of a human subject. This article describes the application, the problems to be solved, and reports on preliminary developmental studies of a first prototype of the tool. Specifically, studies test approaches to simulating real-time dynamic anatomy, and the feasibility in achieving registration of 3-D anatomical bones on their real counterparts. Such a tool will offer several unique advantages over traditional teaching methods and overcome many of their current limitations.

Anatomy↗
PubMed2000

Id proteins are dynamically expressed in normal epidermis and dysregulated in squamous cell carcinoma.

Helix-loop-helix genes regulate many developmental pathways, and growing evidence associates dysregulated expression with tumorigenesis. We observed Id-1, Id-2, and Id-3 mRNA expression in proliferating human keratinocytes in vitro with subsequent down-regulation with differentiation. Immunohistochemical analysis of human tissue sections identified cytoplasmic Id-1 expression and nuclear Id-2 and Id-3 expression in the proliferating layers of the epidermis. Furthermore, we observed a columnar pattern of Id-2 and Id-3 staining, which may relate to the epidermal proliferative unit. In squamous cell carcinoma of the head and neck, Id protein immunoreactivity was observed in the majority of malignant keratinocytes in the most poorly differentiated sections, with reduced staining in well-differentiated disease.

Carcinoma, Squamous Cell↗
PubMed1982

[Relations between pigmentation of the cornea and the number of epidermal melanophores in Rana temporaria L. larvae].

The dynamics of the external cornea pigmentation in Rana temporaria L. larvae at the 22d developmental stage have been studied under conditions favourable for various course of certain morphological reactions in the pigment system. The cornea together with the surrounding skin is transferred on the dorsal surface of the larva body, and the piece of the dorsal surface skin is put instead of the cornea removed. When using the reciprocal transplantation method and preserving the organism's integrity (without disturbing melanocyte-stimulating source--namely, the hypophysis, and melatonine sources--namely, the pineal gland and the lateral eyes) the corneal pigmentation is observed on the background of perfect morphological reactions in the pigment system, while the larvae are maintained on the dark and light substrates, that is at various density of the pigment cells (120 larvae have been used). The pigmentation dynamics have been studied from the 6th up to the 20th day in total preparations. The epidermal melanophores density is estimated in 4 areas of each preparation. The melanin amount is estimated by means of the electron paramagnetic resonance-spectrometry according to the contents of free radicals expressed in relative units. A direct proportional dependence between the significantly higher melanin contents (1.5-fold) and a significantly quicker (1.5-fold) process of the corneal pigmentation is revealed, that agrees with an increasing number of the pigment cells per one unit of the body surface in the larvae maintained on the dark substrate. In the larvae maintained on the light substrate, the dependence is of a reverse character. It is probable that the factors forcing the pigmented cells, at cultivation the neural crest cells in vitro to reject from each other, affect the pigmentation of the larval cornea in vivo. If it is the case, the processes specific for the embryonal period, transgress during the cornea pigmentation at the larval stages of development.

Animals↗
PubMed1998

Development of bony acetabulum in newborns with developmental hip dysplasia.

Trend in the development of bony acetabulum in newborns with developmental hip dysplasia was examined during the first year of life. The study comprised 120 newborns with developmental hip dysplasia. The degree of dysplasia was determined by measuring the acetabular angle (AC) on X-rays of the hips in the anteroposterior projection. The experimental trend curve was most adequate for both the whole group and each subject. The coefficient of trend was assessed by specially designed iterative method. The exhibited trend form allows the extrapolation and prognosis of treatment outcome already after 3-5 measurements of the AC angle. The applied iterative method for the determination of the coefficient of exponential trend iterated rather quickly. The chosen form of the trend curve proved to be adequate for manifestations in which a constant value is expected after a longer period of time. The exponential curve represents a mathematical model of the acetabular development dynamics, with allometric exponents and coefficients of the equation being numerical parameters that define developmental changes. As the AC angle reaches the constant value with the closure of triradiate cartilage, this parameter is an objective measure of the development of bony acetabulum. When assessing the acetabular growth in developmental dysplasia it is necessary to bear in mind that duration, specific position and quantity of newly formed and remodelled bone are determined genetically, and that external factors have a significant influence on the definitive formation.

Acetabulum↗
PubMed2002

A developmental psychopathology perspective on adolescence.

Developmental psychopathology offers an integrative framework for conceptualizing the course of development during adolescence, with particular relevance for understanding continuity and the emergence of psychopathology during this and subsequent developmental periods. In this article, the utility of a developmental psychopathology perspective for informing the design of research, prevention, and intervention is highlighted. Interdisciplinary, organizational models of development, emphasizing the dynamic relations between the developing individual and internal and external contexts, are discussed. Examination of boundaries between abnormal and normal development during adolescence offers important vantage points for articulating diversity in the developmental course during this period. Conceptualizing divergence and convergence in developmental pathways, continuity and discontinuity in development, and the transactions of risk and protective processes leading to maladaptation, psychopathology, and resilience are highlighted.

Adolescent↗
PubMed2001

Osr2, a new mouse gene related to Drosophila odd-skipped, exhibits dynamic expression patterns during craniofacial, limb, and kidney development.

We have isolated a new mouse gene, odd-skipped related 2 (Osr2), that encodes a zinc finger containing protein related to Drosophila Odd-skipped. The putative OSR2 protein shares 65% amino acid sequence identity overall and 98% sequence identity in the zinc finger region, respectively, with the previously reported Osr1 gene product. During mouse embryonic development, Osr2 expression is first detected at E9.25, specifically in the mesonephric vesicles. By E10.0, Osr2 expression is also observed in the rostro-lateral mandibular mesenchyme immediately adjacent to the maxillary processes. In the developing limb buds, Osr2 is expressed in a unique mesenchymal domain and the onset of Osr2 expression follows a distinct dorsal to ventral developmental time sequence beginning in the forelimb and then in the hindlimb. Osr2 exhibits a dynamic expression pattern during craniofacial development, in the mandibular and maxillary processes as well as the developing palate. Osr2 is also expressed at sites of epithelial-mesenchymal interactions during tooth and kidney development.

Amino Acid Sequence↗