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PubMed2005

[The effect of male mating competitiveness, developmental rate, and viability of larvae and pupae in Drosophila melanogaster heterozygous for the temperature-sensitive lethal mutation l(2)M167DTS on the dynamics of the mutation elimination from the population].

The dependence of selection on an introduced mutation 1(2)M167DTS on male mating competitiveness, viability, and developmental rate of larvae and pupae of Drosophila melanogaster, heterozygous for this mutation, was examined in population experiments with preset conditions. The limitations of fitness parameters of individuals l(2)M167DTS/+ relative to individuals +/+ were estimated according to the conditions of the experiment and phenotypic characteristics of the mutation studied. Under conditions of limited food supply and dependence on emergence time in each generation, the sequence of female mating was shown to be of less importance than the order of medium utilization by the progeny of a certain genotype related to the male success in the first mating. The limiting factors acting on the l(2)M167DTS mutation were viability and developmental rate.

Adaptation, Physiological↗
PubMedDate not supplied

Asynchronous language acquisition in developmental dysphasia.

A longitudinal study was conducted to document and compare evolution of children with linguistic acquisition impairment. To determine whether development of the analytic mechanisms underlying linguistic processing occured in similar fashion, two children with mixed developmental dysphasia were assessed from 4 to 5:6 years of age with psycholinguistic tests at 6-months interval. Spontaneous speech and language production (consonant repertory in initial word position, MLU, and lexical diversity) were investigated in a standardized symbolic play context. The phonologic and lexico-morphologic evolution analyses revealed a marked improvement in motor control of phonology and in the application of morphosyntaxic rules in child 1, whereas child 2 was still impaired in phonology and morphosyntax. The singular developmental changes in spontaneous speech results indicate dynamic relationships between various language production facets and variability in the kind of deficit and lexical automation presented by these children. These contrasts in the evolution of language production profiles between child 1 and child 2 also underline the importance of longitudinal studies in the analysis of the atypical linguistic processing paths used by children with developmental dysphasia.

Child Language↗
PubMed2004

Replication of the endosymbiotic bacterium Blochmannia floridanus is correlated with the developmental and reproductive stages of its ant host.

The dynamics of replication of the intracellular endosymbiotic bacterium Blochmannia floridanus was determined during the larval development of its host ant Camponotus floridanus by real-time quantitative PCR. The bacteria were found to proliferate during pupation and immediately after the eclosion of the imagines (adult ants). In older workers the number of bacteria present in the midgut bacteriocytes decreased significantly. In contrast, the bacterial population in the ovaries was dependent on the reproductive state of the animal. An age-dependent degeneration of the midgut bacteriocytes was also investigated by microscopic techniques in males and female castes of the closely related ant species C. herculeanus and C. sericeiventris, respectively, with similar results and supports the concept of age-dependent degeneration of the midgut bacteriocytes in all castes.

Age Factors↗
PubMed1993

Dual diagnoses. Psychiatric disorders in developmental disabilities.

A high prevalence of psychiatric illness exists in persons with mental retardation. Among children with mild to moderate retardation, psychiatric illnesses resemble those seen in the general population. Major affective disorders, ADHD, and conduct disorder are common and respond to the same interventions used in children without mental retardation. Persons with severe to profound retardation are more likely to engage in stereotypies and self-injurious behaviors. In addition, certain specific syndromes associated with mental retardation present with particular neurocognitive, behavioral, and psychiatric profiles. Common examples are fetal alcohol syndrome, Down syndrome, fragile X syndrome, and Rett syndrome. Specific challenges exist for pediatricians who diagnose and treat patients with mental retardation and psychiatric illness. The child's impaired ability to communicate his or her thoughts and feelings with words makes clinical history taking difficult. The clinician must frequently rely on the observation of family members and teachers. An understanding of developmental profiles and interpersonal, peer, and family dynamics is important. Specific behaviors must be targeted and realistic objectives set in treatment planning, which may include psychotherapy, medication, behavior management techniques, and rehabilitation therapy.

Attention Deficit Disorder with Hyperactivity↗
PubMed1986

A measurement of the process of adolescence: standardization and interpretation.

The Objective Measure of Ego Identity Status (Adams, Shea, & Fitch, 1979) was administered to 350 adolescents (12 to 18 years old) to test the Eriksonian theory of a developmental continuum from role diffusion to identity achievement. The results offer construct validity for the dynamic process proposed by Blos and Erikson, but do not support the categorization procedure as set forth by Adams, Shea, and Fitch. The OMEIS questionnaire lends itself to a qualitative and dynamic interpretation rather than to a quantitative and normative approach. It is suggested that the dynamic interpretation is more sensitive to the psychological reality of the developmental process.

Achievement↗
PubMed2004

Distinct neural precursors in the developing human spinal cord.

Both embryonic and adult central nervous system have been shown to contain multipotent neural stem cells, but it is not yet clear whether they consist of a single or distinct populations of neural precursors. Since embryonic human neural precursors, particularly in the spinal cord, have not been extensively characterized, we have studied their behaviour at different days of gestation and in different culture conditions. Depending on dissociation and culture conditions, neurospheres which contain nestin- and vimentin-positive or only vimentin-positive neural precursors can be isolated. Whereas the former can be isolated only at early developmental stages, the latter appear to be present at all the stages examined, between 45 and 89 days of gestation. Furthermore, comparison of the effect of FGF, EGF and the two factors in combination on colony formation shows an additive effect of the two growth factors, indicating the existence of more than one type of neural precursor. Overall our results suggest that the human spinal cord contains distinct and dynamic populations of neural precursors which are developmentally regulated.

Cell Differentiation↗
PubMed2005

Peer relationships and psychopathology in developmental perspective: reflections on progress and promise.

Articles in this special section illuminate progress, challenges, gaps, and future directions for theory and research concerned with peer relations and psychopathology. Advances reflect the emergence of developmental psychopathology, with its emphasis on systems theory, dynamic interactions of individuals in context, processes and change, complexity, integration of normative and pathological development, and longitudinal designs. Gaps reflect the challenges and exciting future ahead for research on peer processes in developmental psychopathology across multiple levels of analysis.

Adolescent↗
PubMed2004

Bioreactor cultivation enhances the efficiency of human embryoid body (hEB) formation and differentiation.

The promise of human embryonic stem cells (hESCs) to provide an unlimited supply of cells for cell therapy and tissue engineering depends on the availability of a controllable bioprocess for their expansion and differentiation. We describe for the first time the formation of differentiating human embryoid bodies (hEBs) in rotating bioreactors to try and control their agglomeration. The efficacy of the dynamic process compared to static cultivation in Petri dishes was analyzed with respect to the yield of hEB formation and differentiation. Quantitative analyses of hEBs, DNA and protein contents, and viable cell concentration, as measures for culture cellularity and scale-up, revealed 3-fold enhancement in generation of hEBs compared to the static culture. Other metabolic indices such as glucose consumption, lactic acid production, and pH pointed to efficient cell expansion and differentiation in the dynamic cultures. The type of rotating vessel had a significant impact on the process of hEB formation and agglomeration. In the slow turning lateral vessel (STLV), hEBs were smaller in size and no large necrotic centers were seen, even after 1-month cultivation. In the high aspect rotating vessel (HARV), hEB agglomeration was massive. The appearance of representative tissues derived from the three germ layers as well as primitive neuronal tube organization, blood vessel formation, and specific-endocrine secretion indicated that the initial developmental events are not altered in the dynamically formed hEBs. Collectively, our study defines the culture conditions in which control over the aggregation of differentiating hESCs is obtained, thus enabling scaleable cell production for clinical and industrial applications.

Apoptosis↗
PubMed2004

Development of goat embryos reconstituted with somatic cells: the effect of cell-cycle coordination between transferred nucleus and recipient oocytes.

The developmental ability and the nucleus and microtubule dynamics of nuclear transplanted goat embryos derived from in vitro matured oocytes were studied while controlling cell-cycle coordination of donor embryonic nuclei and recipient cytoplasts. Three groups of transfers were studied: G0/G1 (after the fibroblast cells grew to 100% confluence) and G2/M (nocodazole treated) phase fibroblasts transferred to MII cytoplasts (G0/G1-->MII and G2/M-->MII group, respectively), and G0/G1 phase fibroblasts transferred to preactivated cytoplasts, mostly at S-phase, (G0/G1-->Pre group) by electrical fusion. The results showed that fusion and developmental ability did not differ between G0/G1-->MII and G0/G1-->Pre groups. However the developmental rate of embryos in the G0/G1-->MII group was significantly higher than that of the G2/M-->MII group. Most fibroblast nuclei (G0/G1 and G2/M) transferred into MII oocytes underwent premature chromosome condensation (PCC). Normal spindle were only detected in the G0/G1-->MII group. In contract, fibroblast nuclei in pre-activated oocytes rarely underwent PCC, but formed a swollen nuclear structure. The data suggest that in vitro matured goat oocytes can support the development of somatic fibroblasts after nuclear transfer, G0/G1 -->MII and G0/G1-->S nuclear transfer might be effective ways for improving the developmental competence of the reconstituted embryos, and that G2/M-->MII nuclear transfer by electrical fusion (even in Ca2+-free fusion medium) induces abnormal chromosome ploidy.

Animals↗
PubMed2003

Chromatin dynamics and Arabidopsis development.

The plant life cycle involves a series of developmental phase transitions. These transitions require the regulation and highly co-ordinated expression of many genes. Epigenetic controls have now been shown to be a key element of this mechanism of regulation. In the model plant Arabidopsis, recent genetic and molecular studies on chromatin have begun to dissect the molecular basis of these epigenetic controls. Chromatin dynamics represent the emerging and exciting field of gene regulation notably involved in plant developmental transitions. By comparing plant and animal systems, new insights into the molecular complexes and mechanisms governing development can be delineated. We are now beginning to identify the components of chromatin complexes and their functions.

Arabidopsis↗
PubMed2003

From unity to atonement: Some religious correlates of Hans Loewald's developmental theory.

Loewald's understanding of ego development offers a way to conceptualise, from a psychoanalytic perspective, those aspects of religious experience that can reflect or contribute to the enrichment of the ego, in contradistinction to the defensive and regressive elements of religious experience that have been well detailed in the psychoanalytic literature in the past. In Loewald's view, a dynamic and metabolic interplay between ego and reality characterises the developmental process. With increasing levels of internalisation, differentiation, individuation and integration, ego and reality are restructured into increasingly resilient and durable forms. An ongoing dialectical tension between separation and reunion provides the driving force for development. Loewald's emphasis on the synthetic rather than defensive aspects of ego functioning forms the basis for his characterisation of sublimation as a 'genuine appropriation' rather than a defence, thus opening up one way to understand non-defensive aspects of religious experience from a psychoanalytic perspective. In the course of this exploration of Loewald's view of ego development and its implications for an understanding of religious experience, the author offers perspectives on Freud's views of religion, on some extreme forms of religious fundamentalism, and on the dynamics of 'mature' faith as illuminated by Loewald's developmental theory.

Ego↗
PubMed1999

Dynamic movement of the ParA-like Soj protein of B. subtilis and its dual role in nucleoid organization and developmental regulation.

The Spo0J and Soj proteins of B. subtilis belong to a widespread family of bacterial proteins required for accurate segregation of plasmids and chromosomes. Spo0J binds to several sites around the oriC region of the chromosome, which are organized into compact foci that may play a centromere-like role in active chromosome segregation. We now show that Soj has a role in organization or compaction of Spo0J-oriC complexes and possibly other regions of the nucleoid. This activity is accompanied by a dynamic localization pattern in which Soj protein undergoes assembly and disassembly into large nucleoid-associated patches on a timescale of minutes. The dynamic behavior of Soj, like its previously described transcriptional repression activity, is controlled by Spo0J. These interactions may constitute a checkpoint coupling developmental transcription to cell cycle progression.

Bacillus subtilis↗
PubMed1998

Microtubule and microfilament dynamics in rat embryos during the two-cell block in vitro.

Developmental block of rat embryo is induced by phosphate at the late two-cell stage. The present study uses immunocytochemistry and laser scanning confocal microscopy to examine microtubule and microfilament dynamics in blocked and nonblocked two-cell-stage rat embryos. Thin fibrous microtubules were distributed homogeneously in the cytoplasm in nonblocked embryos during the interphase of the two-cell stage and then translocated into mitotic spindles at the M-phase. In embryos blocked at the two-cell stage, much thicker fibrous microtubules were formed and distributed as rude meshwork structures in the cytoplasm. Microfilaments were distributed adjacent to nuclei and along the inside of the plasma membrane in nonblocked embryos during the two-cell stage, at M-phase, and at cleavage to the four-cell stage. In embryos blocked at the two-cell stage, however, microfilaments formed granules and dispersed in the cytoplasm. The distribution of microtubules and microfilaments changed relative to the occurrence of two-cell block. In summary, these results indicate that both microtubules and microfilaments are closely involved in the developmental block in two-cell rat embryos.

Actin Cytoskeleton↗
PubMed1990

An introduction to using children's drawings as an assessment tool.

This article is intended to familiarize the ambulatory care provider with possible uses of children's drawings as assessment tools. Drawings can be a useful adjunct in detecting perceptual-motor difficulties and developmental delay, and can provide clues to self-image and family dynamics. Piaget's theory of cognitive development provides a framework to evaluate the child's intellectual development as reflected in drawings. The developmental scales of Koppitz are presented as a practical screening tool. The Koppitz scales include both developmental norms and items that might indicate emotional problems. Observing the child's drawing of the family provides clues to family dynamics. Becoming highly skilled in the evaluation of children's drawings requires a familiarity with neurophysiology, education, psychology, and psychoanalytic and developmental theory, along with intuition and practice. This article presents an introduction to evaluating children's drawings.

Ambulatory Care↗
PubMed2001

Identification of factors mediating the developmental regulation of the early acting -3.9 kb chicken lysozyme enhancer element.

The chicken lysozyme gene -3.9 kb enhancer forms a DNase I hypersensitive site (DHS) early in macrophage differentiation, but not in more primitive multipotent myeloid precursor cells. A nucleosome becomes precisely positioned across the enhancer in parallel with DHS formation. In transfection assays, the 5'-part of the -3.9 kb element has ubiquitous enhancer activity. The 3'-part has no stimulatory activity, but is necessary for enhancer repression in lysozyme non-expressing cells. Recent studies have shown that the chromatin fine structure of this region is affected by inhibition of histone deacetylase activity after Trichostatin A (TSA) treatment, but only in lysozyme non-expressing cells. These results indicated a developmental modification of chromatin structure from a dynamic, but inactive, to a stabilised, possibly hyperacetylated, active state. Here we have identified positively and negatively acting transcription factors binding to the -3.9 kb enhancer and determined their contribution to enhancer activity. Furthermore, we examined the influence of TSA treatment on enhancer activity in macrophage cells and lysozyme non-expressing cells, including multipotent macrophage precursors. Interestingly, TSA treatment was able to restore enhancer activity fully in macrophage precursor cells, but not in non-macrophage lineage cells. These results suggest (i) that the transcription factor complement of multipotent progenitor cells is similar to that of lysozyme-expressing cells and (ii) that developmental regulation of the -3.9 kb enhancer is mediated by the interplay of repressing and activating factors that respond to or initiate changes in the chromatin acetylation state.

AT Rich Sequence↗
PubMed1998

Applying computer modeling to examine complex dynamics and pattern formation of tissue growth.

For research in areas such as developmental biology and cancer, understanding the formation and regrowth of tissue is of great importance. Since complex system behavior makes it difficult to interpret dynamics and pattern formation of tissue growth, it is helpful to have a way to simulate the cell systems and test hypotheses about the mechanisms by which the system is responding. Computer "modeling experiments" can serve this purpose, as we show with an example of the small intestine epithelial cells' response to cytosine arabinoside. This example demonstrates that nonhomogeneities in the cell population can play an important role and emphasizes the need to use a modeling approach, like our spatial modeling, that addresses the differences within the tissue structure. These types of "modeling experiments" can guide researchers with further experiments and provide clues as to how complex cell proliferation behavior is linked to underlying molecular phenomena.

Antimetabolites, Antineoplastic↗
PubMed2003

Setting the stage: developmental biology in pre-college classrooms.

Exercises that employ dynamic living material have proved highly successful at generating interest in science among young students. Developing embryos and larvae are especially well suited for such endeavors, for they can be handled without expensive or elaborate equipment, and their changing nature engages students. Using amphibian embryos, which are relatively large and exhibit profound, easily observed morphological changes, and amphibian larvae, which are easily kept and observed, captures the attention of children. By designing inquiry-based exercises and focused discussion sessions, a high intellectual content can be integrated into these endeavors. The long-term implications for generating an informed citizenry, improving the participation of women in science, and empowering elementary school teachers are profound. Professional developmental biology researchers should feel encouraged to participate in these types of activities.

Ambystoma↗
PubMedDate not supplied

[The dynamics of hormonal status of developing red beet root (Beta vulgaris L.) in correlation with the dynamics of sugar accumulation].

We studied the dynamics of phytohormone levels (indole-3-acetic acid, abscisic acid, cytokinins, and gibberellin-like substances) in red beet (Beta vulgaris L.) roots at different developmental stages in comparison with the data on the dynamics of sugar accumulation in order to test possible hormonal regulation of sugar accumulation. The obtained data suggest the involvement of cytokinins and gibberellin-like substances in the control of sugar accumulation in the roots, while indole-3-acetic acid, abscisic acid, and gibberellin-like substances can control the outflow. The data on the dynamics of phytohormone levels shed light on their specific physiological role in red beet root development.

Beta vulgaris↗