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PubMed2000

Dynamic connexin43 expression and gap junctional communication during endoderm differentiation of F9 embryonal carcinoma cells.

Gap junctional communication permits the direct intercellular exchange of small molecules and ions. In vertebrates, gap junctions are formed by the conjunction of two connexons, each consisting of a hexamer of connexin proteins, and are either established or degraded depending on the nature of the tissue formed. Gap junction function has been implicated in both directing developmental cell fate decisions and in tissue homeostasis/metabolite exchange. In mouse development, formation of the extra embryonal parietal endoderm from visceral endoderm is the first epithelial-mesenchyme transition to occur. This transition can be mimicked in vitro, by F9 embryonal carcinoma (EC) cells treated with retinoic acid, to form (epithelial) primitive or visceral endoderm, and then with parathyroid hormone-related peptide (PTHrP) to induce the transition to (mesenchymal) parietal endoderm. Here, we demonstrate that connexin43 mRNA and protein expression levels, protein phosphorylation and subcellular localization are dynamically regulated during F9 EC cell differentiation. Dye injection showed that this complex regulation of connexin43 is correlated with functional gap junctional communication. Similar patterns of connexin43 expression, localization and communication were found in visceral and parietal endoderm isolated ex vivo from mouse embryos at day 8.5 of gestation. However, in F9 cells this tightly regulated gap junctional communication does not appear to be required for the differentiation process as such.

Animals↗
PubMed1999

Physical and occupational therapy.

Occupational and physical therapists are concerned with an infant's ability to perform in object play and manipulation, self-care, mobility, and social function. Within the realm of child psychiatry, occupational and physical therapists contribute to a comprehensive assessment by providing in-depth neuromotor, sensory processing, and functional or adaptive skill analyses. The three theoretic approaches presented in this article represent the current trends within infant and young child assessment in the fields of occupational and physical therapy. In the past, therapists primarily used neuromotor or developmental assessments. Although these assessments have proven to be adequate for discrimination between children with developmental delays and those who are typically developing, they have not been as useful in documentation of progress in treatment or in providing an understanding of qualitative aspects of movement. Qualitative assessments that are more sensitive to change and to the complexity of functional skills have grown with the development of more sophisticated early-intervention strategies. Assessments based on dynamic systems theory allow therapists to quantify abilities, document subtle changes over time, and provide information on the qualitative aspects of movement. Therapists, however, continue to regularly employ assessments from multiple theoretic approaches to complete comprehensive evaluations.

Child, Preschool↗
PubMed1990

Stage-specific cuticular proteins of Ostertagia circumcincta and Ostertagia ostertagi.

In this study we have shown that NHS-biotin and I125-streptavidin can detect cuticular polypeptides of Ostertagia spp. The labelled polypeptide profile of intact nematodes is simple compared to the profile obtained by labelling homogenates. None of the major internal polypeptides are labelled and the subset of proteins labelled in intact nematodes appears to be mainly surface associated. The results presented here demonstrate that NHS-biotin may be used as a reagent for the analysis of surface polypeptides. The surface polypeptide profiles of the five major developmental stages (L1, L2, L3, L4 and adult) of Ostertagia circumcincta show a series of stage-specific molecules with no polypeptides common to all stages, indicating that the cuticle is a dynamic structure which changes throughout the life cycle. Similarily comparison of Ostertagia ostertagi L3 and L4 stage surface profiles showed that each stage is clearly distinct; comparison of these stages between the two species shows an overall similarity.

Animals↗
PubMed1997

Sox genes find their feet.

The identification of the mammalian testis-determining factor, SRY, led to the description of a new class of genes encoding transcription factors, the SOX gene family. SOX proteins display properties of both classical transcription factors and architectural components of chromatin. The dynamic and diverse patterns of expression of SOX genes and analysis of mutations in humans, mice and Drosophila suggest that SOX factors play key roles in decisions of cell fate during diverse developmental processes.

Animals↗
PubMed2002

SCAR is a primary regulator of Arp2/3-dependent morphological events in Drosophila.

The Arp2/3 complex and its activators, Scar/WAVE and Wiskott-Aldrich Syndrome protein (WASp), promote actin polymerization in vitro and have been proposed to influence cell shape and motility in vivo. We demonstrate that the Drosophila Scar homologue, SCAR, localizes to actin-rich structures and is required for normal cell morphology in multiple cell types throughout development. In particular, SCAR function is essential for cytoplasmic organization in the blastoderm, axon development in the central nervous system, egg chamber structure during oogenesis, and adult eye morphology. Highly similar developmental requirements are found for subunits of the Arp2/3 complex. In the blastoderm, SCAR and Arp2/3 mutations result in a reduction in the amount of cortical filamentous actin and the disruption of dynamically regulated actin structures. Remarkably, the single Drosophila WASp homologue, Wasp, is largely dispensable for these numerous Arp2/3-dependent functions, whereas SCAR does not contribute to cell fate decisions in which Wasp and Arp2/3 play an essential role. These results identify SCAR as a major component of Arp2/3-dependent cell morphology during Drosophila development and demonstrate that the Arp2/3 complex can govern distinct cell biological events in response to SCAR and Wasp regulation.

Actin-Related Protein 2↗
PubMed2026

Bayesian inference of lineage trees by joint analysis of single-cell multimodal lineage-tracing data with BiLinT.

The advent of single-cell lineage-tracing technologies has enabled the simultaneous profiling of gene expression and lineage barcodes. However, accurate, high-resolution reconstruction of cell lineage trees remains challenging because most existing approaches treat these modalities separately and therefore fail to fully exploit their complementary information. Here we present BiLinT, a Bayesian framework that jointly models multimodal single-cell lineage-tracing data for lineage tree reconstruction. BiLinT integrates barcode evolution (a continuous-time Markov chain) with gene expression dynamics (an Ornstein-Uhlenbeck process) within a unified probabilistic model. Across synthetic and real data sets, BiLinT provides accurate lineage-tree reconstruction and reveals differentiation-associated clonal structure and developmental fate biases.

Journal Article↗
PubMed2006

Asymmetrical interactions between Wolbachia and Spiroplasma endosymbionts coexisting in the same insect host.

We investigated the interactions between the endosymbionts Wolbachia pipientis strain wMel and Spiroplasma sp. strain NSRO coinfecting the host insect Drosophila melanogaster. By making use of antibiotic therapy, temperature stress, and hemolymph microinjection, we established the following strains in the same host genetic background: the SW strain, infected with both Spiroplasma and Wolbachia; the S strain, infected with Spiroplasma only; and the W strain, infected with Wolbachia only. The infection dynamics of the symbionts in these strains were monitored by quantitative PCR during host development. The infection densities of Spiroplasma exhibited no significant differences between the SW and S strains throughout the developmental course. In contrast, the infection densities of Wolbachia were significantly lower in the SW strain than in the W strain at the pupal and young adult stages. These results indicated that the interactions between the coinfecting symbionts were asymmetrical, i.e., Spiroplasma organisms negatively affected the population of Wolbachia organisms, while Wolbachia organisms did not influence the population of Spiroplasma organisms. In the host body, the symbionts exhibited their own tissue tropisms: among the tissues examined, Spiroplasma was the most abundant in the ovaries, while Wolbachia showed the highest density in Malpighian tubules. Strikingly, basically no Wolbachia organisms were detected in hemolymph, the principal location of Spiroplasma. These results suggest that different host tissues act as distinct microhabitats for the symbionts and that the lytic process in host metamorphosis might be involved in the asymmetrical interactions between the coinfecting symbionts.

Animals↗
PubMed2006

Vacuolar membrane dynamics in the filamentous fungus Aspergillus oryzae.

Vacuoles in filamentous fungi are highly pleomorphic and some of them, e.g., tubular vacuoles, are implicated in intra- and intercellular transport. In this report, we isolated Aovam3, the homologue of the Saccharomyces cerevisiae VAM3 gene that encodes the vacuolar syntaxin, from Aspergillus oryzae. In yeast complementation analyses, the expression of Aovam3 restored the phenotypes of both Deltavam3 and Deltapep12 mutants, suggesting that AoVam3p is likely the vacuolar and/or endosomal syntaxin in A. oryzae. FM4-64 [N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenyl-hexatrienyl)pyridinium dibromide] and CMAC (7-amino-4-chloromethylcoumarin) staining confirmed that the fusion protein of enhanced green fluorescent protein (EGFP) with AoVam3p (EGFP-AoVam3p) localized on the membrane of the pleomorphic vacuolar networks, including large spherical vacuoles, tubular vacuoles, and putative late endosomes/prevacuolar compartments. EGFP-AoVam3p-expressing strains allowed us to observe the dynamics of vacuoles with high resolutions, and moreover, led to the discovery of several new aspects of fungal vacuoles, which have not been discovered so far with conventional staining methods, during different developmental stages. In old hyphae, EGFP fluorescence was present in the entire lumen of large vacuoles, which occupied most of the cell, indicating that degradation of cytosolic materials had occurred in such hyphae via an autophagic process. In hyphae that were not in contact with nutrients, such as aerial hyphae and hyphae that grew on a glass surface, vacuoles were composed of small punctate structures and tubular elements that often formed reticulum-like networks. These observations imply the presence of so-far-unrecognized roles of vacuoles in the development of filamentous fungi.

Aspergillus oryzae↗
PubMed2003

Efficiency of alternative policy options for screening for developmental dysplasia of the hip in the United Kingdom.

AIMS: To assess, using a decision model, the efficiency of ultrasound based and clinical screening strategies for developmental dysplasia of the hip. METHODS: The additional cost per additional favourable outcome was compared for the following strategies: clinical screening alone using the Ortolani and Barlow tests; addition of static and dynamic ultrasound examination of the hips of all infants (universal ultrasound) or restricted to infants with defined risk factors (selective ultrasound); "no screening" (that is, clinical diagnosis only). RESULTS: Ultrasound based screening strategies are predicted to be more effective but more costly than clinical screening or no screening. Estimated total costs per 100,000 live births are approximately pound 4 million for universal ultrasound, pound 3 million for selective ultrasound, pound 1 million for clinical screening alone, and pound 0.4 million for no screening. The relative efficiency of selective ultrasound and clinical screening is poorly differentiated, and depends on how infants are selected for ultrasound as well as the expertise of clinical screening examiners. If training costs less than pound 20 per child screened, clinical screening alone would be more efficient than selective ultrasound. Relative to no screening, each of the 16 additional favourable outcomes achieved as a result of selective ultrasound costs approximately pound 0.2 million, while each of the five favourable outcomes achieved through universal ultrasound screening, over and above selective ultrasound, costs approximately pound 0.3 million. CONCLUSIONS: Policy choice depends on values attached to the different outcomes, willingness to pay to achieve these and total budget.

Child, Preschool↗
PubMed2000

Limb malformations and abnormal sex hormone concentrations in frogs.

Declines in amphibian populations, and amphibians with gross malformations, have prompted concern regarding the biological status of many anuran species. A survey of bullfrogs, Rana catesbeiana, and green frogs, Rana clamitans, conducted in central and southern New Hampshire showed malformed frogs at 81% of the sites sampled (13 of 16 sites). Brain gonadotropin-releasing hormone (GnRH) and the synthesis of androgens and estradiol, hormones essential to reproductive processes, were measured from limb-malformed and normal (no limb malformation) frogs. Normal frogs had significantly higher concentrations (nearly 3-fold) of in vitro produced androgens and of brain GnRH than malformed frogs. Because most malformations are thought to occur during development, we propose that environmental factors or endocrine-disrupting chemicals that may cause developmental abnormalities also act during early development to ultimately cause abnormally reduced GnRH and androgen production in adult frogs. The consequences of reduced GnRH and androgens on anuran reproductive behavior and population dynamics are unknown but certainly may be profound and warrant further research.

Androgens↗
PubMed2006

Fluorescent reporter methods.

The identification and cloning of the green fluorescent protein (GFP) from jellyfish marks the beginning of a new era of fluorescent reporters. In Caenorhabditis elegans, genetically encoded markers like the fluorescent proteins of the GFP family became the reporter of choice for gene expression studies and protein localization. The small size and transparency of the worm allows the visualization of in vivo dynamics, which increases the number of potential applications for fluorescent reporters tremendously. In combination with subcellular tags, GFP can be used to label subcellular structures like synapses allowing novel approaches to study developmental processes like synapse formation. Other fluorescent labels like small organic dyes, which are in widespread use in cell culture systems, are rarely used in C. elegans owing to difficulties in applying these labels through the impenetrable cuticle or eggshell of the animal. A notable exception is the use of lipophilic dyes, which are taken up by certain sensory neurons in the intact animal and can be introduced into the embryo after puncturing of the egg shell. This chapter covers the use of fluorescent dyes and fluorescent proteins in C. elegans. Emphasis is placed on microscopic techniques including wide field and confocal microscopy as well as time-lapse recordings. The use of fluorescent proteins as transgenic markers and image processing of fluorescence images are briefly discussed.

Animals↗
PubMedDate not supplied

[Study of the mutagenic and embryotoxic action of etidin].

Investigations of mutagenic and embryotoxic action of ethidine were conducted on animals. The possibility of the mutagenic action of ethidine (in doses of 2500 and 1000 mg/kg of the body mass) was verified on mongrel albino mice through investigation of chromosomal aberration in the bone marrow cells. The embryotoxicity was studied on mongrel albino rats with introduction of the compound (in doses of 100 and 500 mg/kg to pregnant female rats at the time of implantation or organogenesis. On the 20th day of development the mass, length, external and internal developmental anomalies were noted along with observations carried on over the progency in the post-natal period. Opening of the eyes and the appearance of the hair tegmentum were recorded and dynamic changes in the body mass observed for a period of 2 months. In tests 14 mice were used from which 1300 cells were obtained and examined at the stage of metaphase and 50 female rats from which 307 embryos and 183 rattlings were studied in the post-natal period. Investigations failed to reveal any mutagenic of embryotoxic action of ethidine, nor its influence on the progeny in the post-natal period.

Animals↗
PubMed1984

Observations on the dynamics of argyrophilic nucleolar material in the nuclei of mice spermatids.

Applying a new silver staining technique it could be shown that in very early spermatids strong argyrophilia in nucleoli is confined to their granular and fibrillar components; fibrillar centers are devoid of silver. During subsequent developmental stages remnants of these nucleolar components are present in the form of intensively silver stained clusters of coiled fibers. As chromatin condensation proceeds, these fibrous structures decrease in size and density and are finally completely absent. The nucleus of the mature sperm contains only the space in which they formerly existed, now silver negative, as the so-called 'nuclear vacuole'.

Animals↗
PubMed1989

Potential use of Doppler ultrasound in developmental pharmacology.

The non-invasive study of the human fetal circulation is now possible using Doppler ultrasound techniques. Until recently, these methods have been used to study fetal physiology but are increasingly being used to assess the effect of maternally administered drugs on fetal cardiovascular dynamics. Drugs studied include established and experimental antihypertensive treatments, tocolytics and regional anaesthetics. This new application of Doppler ultrasound will increase our knowledge of drug effects in pregnancy and provides a new method of assessing novel treatments.

Female↗
PubMed2001

Neuromotor development from 5 to 18 years. Part 1: timed performance.

Timed performance in specific motor tasks is an essential component of a neurological examination applied to children with motor dysfunctions. This article provides centile curves describing normal developmental course and interindividual variation of timed performances of non-disabled children from 5 to 18 years. In a cross-sectional study (n=662) the following motor tasks were investigated: repetitive finger movements, hand and foot movements, alternating hand and foot movements, sequential finger movements, pegboard, and dynamic and static balance. Intraobserver, interobserver, and test-retest reliability for timed measurements were moderate to high. Timed performances improved throughout the entire prepubertal period, but differed among various motor tasks with respect to increase in speed and when the 'adolescent plateau' was reached. Centile curves of timed performance displayed large interindividual variation for all motor tasks. At no age were clinically relevant sex differences noted, nor did socioeconomic status significantly correlate with timed performance. Our results demonstrate that timed motor performances between 5 and 18 years are characterized by a long-lasting developmental change and a large interindividual variation. Therefore, a well standardized test instrument, and age-specific standards for motor performances are necessary preconditions for a reliable assessment of motor competence in school-age children.

Adolescent↗
PubMed1997

The effects of poverty on child health and development.

Poverty has been shown to negatively influence child health and development along a number of dimensions. For example, poverty-net of a variety of potentially confounding factors-is associated with increased neonatal and postneonatal mortality rates, greater risk of injuries resulting from accidents or physical abuse/neglect, higher risk for asthma, and lower developmental scores in a range of tests at multiple ages. Despite the extensive literature available that addresses the relationship between poverty and child health and development, as yet there is no consensus on how poverty should be operationalized to reflect its dynamic nature. Perhaps more important is the lack of agreement on the set of controls that should be included in the modeling of this relationship in order to determine the "true" or net effect of poverty, independent of its cofactors. In this paper, we suggest a general model that should be adhered to when investigating the effects of poverty on children. We propose a standard set of controls and various measures of poverty that should be incorporated in any study, when possible.

Asthma↗