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PubMed2004

Sexual and temporal dynamics of molecular evolution in C. elegans development.

Dissection of the phenotypic and molecular details of development and differentiation is a centuries-old topic in evolutionary biology. However, an adequate understanding is missing for the molecular evolution of genes that are expressed differentially throughout development-across time, tissues, and the sexes. In this study, we investigate the dynamics of gene evolution across Caenorhabditis elegans ontogeny and among genes expressed differentially between each sex and gamete type. Using gene classes identified by genome-wide gene expression developmental time series and comparative sequence analysis with the congener C. briggsae, we demonstrate that genes expressed predominantly after reproductive maturity evolve more rapidly than genes expressed earlier in development and that genes expressed transiently during embryogenesis evolve faster than other embryonic transcripts. These results are indicative of relaxed selection on genes expressed after maturity, in accord with the mutation-accumulation model of aging. Furthermore, genes involved in spermatogenesis reveal more rapid evolution than other phenotypic classes of genes. Average rates of evolution among male soma-related genes indicates that selection acts to maintain males in these androdioecious species, despite their rarity, and the rapid evolution of sperm genes suggests that sexual selection acts on sperm development and function.

Aging↗
PubMed1996

Containers, mental space and psychodynamics.

The concept of the container has a place within cognitive science as well as within psychodynamic theories. Cognitive semantics has shown that many metaphors giving meaning to daily life-events use the container as a basic reference point. Psychoanalytic theory, most notably, Freud's psychosexual developmental model, illustrates how the container of the body results in meaning. Object relations theory in psychoanalysis has shown how patients with borderline personality disorder behave according to the dynamics of container and containment. Both the cognitive and the psychodynamic conceptions of containers are clinically relevant. The fundamental notion of the container leads to an exploration of 'container dynamics' both in cognitive semantics and in psychodynamic work. A model of the cusp may be of help in the description of the dynamics at the border of the container. Furthermore, the descriptions of the patient's communication of emotion and thoughts may involve three interacting dimensions: an effective-perceptual dimension, a phantasy dimension and a socio-interactive dimension. The interaction between these dimensions has implications for dealing with container dynamics and the process of containment.

Borderline Personality Disorder↗
PubMed2002

Systematic determination of patterns of gene expression during Drosophila embryogenesis.

BACKGROUND: Cell-fate specification and tissue differentiation during development are largely achieved by the regulation of gene transcription. RESULTS: As a first step to creating a comprehensive atlas of gene-expression patterns during Drosophila embryogenesis, we examined 2,179 genes by in situ hybridization to fixed Drosophila embryos. Of the genes assayed, 63.7% displayed dynamic expression patterns that were documented with 25,690 digital photomicrographs of individual embryos. The photomicrographs were annotated using controlled vocabularies for anatomical structures that are organized into a developmental hierarchy. We also generated a detailed time course of gene expression during embryogenesis using microarrays to provide an independent corroboration of the in situ hybridization results. All image, annotation and microarray data are stored in publicly available database. We found that the RNA transcripts of about 1% of genes show clear subcellular localization. Nearly all the annotated expression patterns are distinct. We present an approach for organizing the data by hierarchical clustering of annotation terms that allows us to group tissues that express similar sets of genes as well as genes displaying similar expression patterns. CONCLUSIONS: Analyzing gene-expression patterns by in situ hybridization to whole-mount embryos provides an extremely rich dataset that can be used to identify genes involved in developmental processes that have been missed by traditional genetic analysis. Systematic analysis of rigorously annotated patterns of gene expression will complement and extend the types of analyses carried out using expression microarrays.

Animals↗
PubMed2003

Separable roles of UFO during floral development revealed by conditional restoration of gene function.

The UNUSUAL FLORAL ORGANS (UFO) gene is required for several aspects of floral development in Arabidopsis including specification of organ identity in the second and third whorls and the proper pattern of primordium initiation in the inner three whorls. UFO is expressed in a dynamic pattern during the early phases of flower development. Here we dissect the role of UFO by ubiquitously expressing it in ufo loss-of-function flowers at different developmental stages and for various durations using an ethanol-inducible expression system. The previously known functions of UFO could be separated and related to its expression at specific stages of development. We show that a 24- to 48-hour period of UFO expression from floral stage 2, before any floral organs are visible, is sufficient to restore normal petal and stamen development. The earliest requirement for UFO is during stage 2, when the endogenous UFO gene is transiently expressed in the centre of the wild-type flower and is required to specify the initiation patterns of petal, stamen and carpel primordia. Petal and stamen identity is determined during stages 2 or 3, when UFO is normally expressed in the presumptive second and third whorl. Although endogenous UFO expression is absent from the stamen whorl from stage 4 onwards, stamen identity can be restored by UFO activation up to stage 6. We also observed floral phenotypes not observed in loss-of-function or constitutive gain-of-function backgrounds, revealing additional roles of UFO in outgrowth of petal primordia.

Arabidopsis↗
PubMed1997

3-dimensional kinematics of overarm throwing action of children age 15 to 30 months.

7 children 15 to 30 mo. old participated in a study of 3-dimensional kinematics of overarm throwing. Children of different ages were considered to be at different developmental stages of motor development. Video recordings were digitised and 3-dimensional coordinates established using the DLT algorithm. Qualitative analysis indicated that the children executed either a 'static' or 'dynamic' throwing action. Either could further be classified as 'arm dominated' or 'sequentially linked.' Maximum elbow extension was no more than 163 degrees for any child; release velocity was higher for older subjects; and the angle of ball release was large in 'arm-dominated throws' (M = 49 degrees) and comparatively smaller in 'sequentially linked' throws (M = 15 degrees).

Age Factors↗
PubMed2000

[Analyses of the population structures of Mallophaga infesting urban pigeons].

A total of 70 pigeons from Cracow area was examined and the representation of bird lice (Mallophaga) infesting them estimated. Mostly the populations of two dominant species: Columbicola columbae columbae (L.) and Campanulotes bidentatus compar (Burm.) were assessed. 47% of birds inspected had less than 100 specimens of Mallophaga, although the highest infested one had 900 specimens. Sex and age of pigeons did not influence the number of bird lice present, and only weak health condition of individuals allowed higher infestation. The sex structure of ectoparasites was balanced, with a slightly higher number of females during the year of study. The highest number of bird lice was detected in autunm and the larvae definitely predominated then, as well. Similar tendency was observed in C. c. columbae populations. The course of age dynamic of C. b. compar was somewhat different, having the peak in July, and the imago stage dominated in this species. The populations of in C. c. columbae showed developmental signs, whereas the population structures of C. b. compar gave evidence of their regression.

Animals↗
PubMed1979

[Longitudinal studies on the physical development of low birth weight children. Growth dynamics and sexual dimorphism during the first year of life].

Longitudinal studies of physical development in the first year of life were carried out in the group of children born with low body weight. Results were compared with those obtained in the control group. The examined group consisted of 73 children born from single pregnancies in hospitals from families living in Wola district of Warsaw. Out of 73 children, 35 were born t term as small-for-date children (DW). Remaining 38 children were prematurely born (W). The control group (K) consisted of 40 children born in hospital at term, from single pregnancy, with body-weight at birth corresponding to foetal age (25-75 centiles). They came also from families living in Wola district. Analysis of physical development was based on the results of anthropometric measurements carried out at monthly intervals through the first year of life, considering required age tolerance, using standardized measuring methods and instruments. The principles of feeding, nursing, prophylaxis of rickets and iron deficiency as well as preventive vaccinations were the same for all children. Variability with age as well as monthly and yearly gains and the index of sexual dimorphism of the following parameters were analysed: body-weight, body-length, head and chest circumference thorax and head length, shoulders width, hip width. Longitudinal observation of these children through evaluation of growth increments made the analysis of the dynamics of somatic development possible. The analysis showed differences in physical development in the first year of life in children under examination. These differences concerned both the variability of separate traits with age, and the dynamics of development, development of sexual dimorphism index in relation to the control group. The differences ere also observed between the small-to-date and prematurely born children. Developmental differences ere noted among the children born with low body-weight dependent on the achieved foetal age at birth. No tendency in small-for-date infants to decrease the differences as compared to the control group was noted. This tendency was typical of the prematurely born children. The highest developmental rate was observed in prematurely born infants.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1984

[Pigmentation of the outer cornea after removal of the eye from Rana lessonae Camerano larvae].

Dynamics and morphological peculiarities of pigmentation in the external cornea after removal of the eye in larvae of Rana lessonae Camerano have been studied in situ depending on the developmental stage during prometamorphosis. The results are compared with the previously obtained data for tadpoles of Rana temporaria (D. V. Popov, Sokolova Z. A., Kalistratova E. N. et al., 1982). The process of pigmentation in the cornea does not depend on the developmental stage, proceeds with a constant rate and accomplishes before the beginning of the metamorphous climax. In the Rana lessonae tadpoles the dermal chromatomorphous units differentiate earlier than in the Rana temporaria larvae. The period of metamorphosis in the R. lessonae is 2 times as long as in the R. temporaria. At the same time, transplantation of the epidermal melanophores during the process of the cornea pigmentation in these species is realized with the same rate. Thus, in this case, the phenomena occurring at the cellular and organism levels are rather autonomous. The differences revealed between the cornea pigmentation in the R. lessonae and R. temporaria larvae are explained as the phenomenon of interlevel heterochrony in ontogenesis.

Animals↗
PubMed1993

Autoradiographic studies on 3H-fucose incorporation into manubria and its translocation to antheridial space during spermatogenesis in Chara vulgaris L.

The internal space of antheridium in Chara vulgaris L. is filled with the PAS-positive polysaccharide mucilage. It is produced and secreted by non-generative, polyploidal cells--manubria. Autoradiographic studies with the use of 3H-fucose have shown that this precursor is incorporated into polysaccharidial compounds at the manubrium surface. The dynamics of this process is different in proliferative phase than after symplasmic isolation of antheridium. The translocation of mucilage into antheridial space is very intensive, especially at the older developmental stages of antheridium. The data obtained after 12-hour postincubation indicated secondary metabolic changes of mucilage. The decrease in total radioactivity per investigated section is most intensive by the end of spermatogenesis. These facts seem to confirm the assumption about nutritive role of mucilage filling Chara antheridium during the process of spermatogenesis.

Autoradiography↗
PubMed2026

Histone H3K9 methyltransferases regulate cortical growth by coordinating heterochromatin formation and neural progenitor dynamics.

DNA packaging into heterochromatin is a fundamental mechanism of transcriptional silencing, yet its role in regulating neural progenitor behavior during brain development remains poorly understood. Trimethylation of histone H3 lysine 9 (H3K9me3), catalyzed by the methyltransferases SETDB1, SUV39H1, and SUV39H2, is a defining feature of heterochromatin, but functional redundancy among these enzymes has obscured their developmental roles. Here, we generated a cortex-specific triple knockout mouse model lacking Setdb1, Suv39h1, and Suv39h2 to directly interrogate H3K9me3 function during corticogenesis. Combined loss of H3K9 methyltransferases caused genome-wide depletion of H3K9me3, disruption of neural progenitor cell-cycle progression, and impaired cortical neurogenesis, resulting in microcephaly. H3K9 methyltransferases preserve neural progenitor identity and function by silencing clustered protocadherins, meiosis-associated genes, and a cell-cycle restraint program through H3K9me3 deposition. Loss of H3K9me3 promoted local chromatin opening and increased transcription factor occupancy, enabling transposable elements to acquire cryptic enhancer activity and modulate proximal gene expression. Together, these findings establish H3K9me3 heterochromatin as an active regulator of neural progenitor dynamics and lineage fidelity, revealing a central epigenetic mechanism that restricts aberrant transcriptional programs to ensure cortical growth.

Cerebral Cortex↗
PubMed2002

Dynamic regulation of Smad expression during mesenchyme to epithelium transition in the metanephric kidney.

Genetic studies have revealed a role for the transforming growth factor beta (TGFbeta) superfamily growth factors in development of the mouse kidney. In this study, we have characterized developmental expression of Smad proteins, the downstream effectors of TGFbeta superfamily ligands. Immunohistochemistry detecting Smads 1-5 and 8 was performed on 11.25-15.5 dpc kidney sections. We find that Smad proteins are readily detected in metanephric mesenchyme but are coordinately down-regulated in condensing mesenchyme and derivative structures such as renal vesicles. In order to define the stage at which down-regulation occurs, we used the heterologous inducer lithium chloride to promote condensation in isolated cultured mesenchymal explants and subsequently assayed expression of Smad 4. Down-regulation is complete in lithium chloride induced mesenchymal condensates, indicating that Smad regulation takes place at an early stage, prior to mesenchyme to epithelium transition.

Animals↗
PubMed2007

Regulatory T cells maintain long-term tolerance to myelin basic protein by inducing a novel, dynamic state of T cell tolerance.

The pathogenesis of multiple sclerosis involves a breakdown in T cell tolerance to myelin proteins like myelin basic protein (MBP). Most MBP-specific T cells are eliminated by central tolerance in adult mice, however, the developmentally regulated expression of MBP allows MBP-specific thymocytes in young mice to escape negative selection. It is not known how these T cells that encounter MBP for the first time in the periphery are regulated. We show that naive MBP-specific T cells transferred into T cell-deficient mice induce severe autoimmunity. Regulatory T cells prevent disease, however, suppression of the newly transferred MBP-specific T cells is abrogated by activating APCs in vivo. Without APC activation, MBP-specific T cells persist in the periphery of protected mice but do not become anergic, raising the question of how long-term tolerance can be maintained if APCs presenting endogenous MBP become activated. Our results demonstrate that regulatory T cells induce naive MBP-specific T cells responding to nonactivated APCs to differentiate into a unique, tolerized state with the ability to produce IL-10 and TGF-beta1 in response to activated, but not nonactivated, APCs presenting MBP. This tolerant response depends on continuous activity of regulatory T cells because, in their absence, these uniquely tolerized MBP-specific T cells can again induce autoimmunity.

Animals↗
PubMed2003

Sex dimorphism in development dynamics and in development progression of morphological features in human foetuses.

The study material comprised 3889 foetuses of both sexes, aged 20-42 weeks. t-Student test has been applied to evaluate the existence of potential sex-dependent differentiation of developmental trends as assessed by weekly measurements of selected somatic features and by the weight of internal organs. The regression coefficients of the analysed variables have been compared against the opposite sex. The rate of development of the analysed features in consecutive weeks has been found to be sex-related. Highest sex-related differences have been observed for the total body weight and for the weight of internal organs, with the exception of the adrenals, and the differences have been significant enough to justify the existence of contrasting, sex-dependent patterns of development of the analysed variables. The development of the analysed morphological features has been depicted by curvilinear regression. When described by various degree polynomials the development course of the analysed features displays sex-related differences. Only the change in the weight of the adrenals is similar for both sexes. The evaluation of the developmental advancement of the analysed features has revealed that they are usually at a more advanced development level in female foetuses.

Body Height↗
PubMed2005

[Dynamic change of ATPase activity on amyloplasts and protein bodies during the endosperm development in rice (Oryza sative L.)].

The ultracytochemical localizations of ATPase activity on amyloplasts and protein bodies were studied by using a lead precipitation technique at middle and late developmental stage of endosperm in rice (Oryza sativa L. cv. Minghui 63). The results showed that the inner and outer plasma membrane of amyloplasts, the web-like passages among starch grains and the amorphous substance surrounding the amyloplasts exhibited high ATPase activity. ATPase activity products were present on the membranes of protein body I and protein body II, and on the vacuoles and vesicle-like structures surrounding protein bodies. Active products of ATPase were also located on the plasma membrane and cell wall of starchy endosperm cells, on the cell wall, plasma membrane, nucleus and plasmodesma of aleurone and subaleurone layer cells. According to the distribution pattern of active products of ATPase, we infer that the web-like passage in amyloplast may be the transporting channel for nutrients flowing into the amyloplast. The ATPase on amyloplasts and protein bodies can supply the power for nutrients passing through the plasma membranes.

Adenosine Triphosphatases↗
PubMed1997

Developmental expression of two rat sialyltransferases that modify the neural cell adhesion molecule, N-CAM.

Polysialylation of the neural cell adhesion molecule (N-CAM) reduces the efficacy of N-CAM-mediated homophilic binding and is regulated both during development and in regions undergoing neurogenesis or remodeling in the adult. Hamster PST-1 (PST) and rat STX are two related sialytransferases that catalyze the polysialylation of N-CAM. We have isolated a cDNA clone for the rat homologue of PST and compared its amino acid and nucleotide sequence to that of rat STX. This analysis revealed regions of high sequence similarity corresponding to the enzymatic domains of the two molecules. Other regions of lower similarity were used to generate specific probes for in situ hybridization. The distribution of PST and STX mRNAs, polysialic acid, and N-CAM were analyzed at three developmental stages. PST and STX mRNAs were expressed abundantly throughout the nervous system at embryonic day 15 and postnatal day 4 and were coexpressed in most tissues examined. In the adult brain, STX expression was reduced relative to PST and expression of both mRNAs was restricted to subsets of cells in areas undergoing constant synaptic rearrangement including hippocampus and olfactory system. The results suggest that both PST and STX participate in the polysialylation of N-CAM in vivo and that their expression levels are dynamically controlled during development and regeneration.

Amino Acid Sequence↗
PubMed2002

Expression and developmental regulation of gap junction connexins cx26, cx32, cx43 and cx45 in the rat midbrain-floor.

Connexins (cx) constitute a family of transmembrane proteins that form gap junction channels allowing metabolic and electrical coupling of cellular networks. Initial studies on the expression of cx in the developing brain have suggested that cx may undergo dynamic changes and may possibly be implicated in synchronizing development and differentiation of neural progenitor cells and young neurons. We have investigated expression of cx26, cx32, cx43, and cx45 in the midbrain floor, where nigrostriatal dopaminergic neurons originate and differentiate. This neuron population is of major importance in regulating motor-functions. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) revealed low levels of cx26-mRNA in the midbrain floor at E12, which gradually increased during pre- and postnatal development, reaching a maximum in the adult. Cx32-mRNA-levels reached a first peak at E16, and showed highest levels in adulthood. Cx43 was highly expressed at E12, decreased until E18, and subsequently increased again until adulthood. Cx45 mRNA was prominent at all developmental ages, but slightly decreased after the first postnatal week. Double-labeling for the dopaminergic neuronal marker tyrosine hydroxylase (TH), and cx-immunoreactivities (ir) evaluated by quantitative confocal laser microscopy revealed both distinct and similar developmental patterns for the individual cx investigated. Cx26 was highest at E14, decreased towards birth, and subsequently increased again reaching about 50% of the E14 level in the adult. Cx32-ir peaked at E16 and dropped to low levels after birth. Cx43-ir was highest at E12, decreased sharply at E14, reached its lowest levels at birth, but modestly increased again afterwards. Cx45-ir showed a biphasic pattern, with two prominent peaks at E12 and E18, followed by a massive postnatal decrease. Taken together, our results reveal that expression and ir of cx in the midbrain floor and dopaminergic neurons, respectively, follow cx-type specific patterns that temporally coincide with important steps of midbrain morphogenesis, as e.g. progenitor cell formation and migration (E12), early differentiation (E14-16), target encounter (E16-18) and postnatal functional maturation of the nigrostriatal system.

Animals↗
PubMed2026

Microbial allies in a cotton pest: A descriptive account of associated microbiota dynamics in Dysdercus cingulatus across development.

BACKGROUND: Hemipteran insects harbour several symbiotic partners, mainly bacteria, which play pivotal roles for hosts like dietary provision, support overall physiology, xenobiotic degradation and manipulate/regulate behaviour. Most of these symbionts usually reside and operate from the digestive tracts of the animals. Cotton is one of the major cash crops in India and Dysdercus cingulatus (D. cingulatus) though a secondary pest, is causing significant destruction of cotton bolls, poor lint quality and reduce oil content of seeds. Premature opening of cotton bolls often leads to bacterial and fungal infections, thus resulting in extensive economic loss worldwide. D. cingulatus is a hemimetabolous insect that comprises of developmental stages like egg, nymph (5 instar stages), and adult. The present work explored the ontogeny specific diversity in the associated microbiota and predicted their probable functional inputs in D. cingulatus. RESULTS: The data obtained using 16S rRNA gene sequencing (NovaSeq 6000) revealed presence of members of Proteobacteria (65.83%), Firmicutes (24%), Actinobacteria (10%) phyla throughout the ontogeny of D. cingulatus. Highest alpha diversity of these symbiotic bacteria was recorded in the third instar nymphs in contrast to rest of the developmental stages. Among all the observed genera, Stenotrophomonas, Hungatella and Glutamicibacter were predominant from egg to adult stages. MicFunPred, a tool used for predicting the probable functional inputs of these symbionts, hinted at their probable stage specific contribution in crucial biochemical pathways such as polyketide biosynthesis, ascorbate/aldarate metabolism, pentose phosphate and glyoxylate cycles, steroid hormone and peptidoglycan biosynthesis, and glycolysis/pyruvate metabolism. CONCLUSIONS: The primary investigations on the ontogenetic composition and diversity of associated microbiota, suggest dynamic shifts in D. cingulatus, concurrent with their probable functions/roles in the host development and metabolism. To the best of our knowledge, this is the first report on symbiotic microbiota variation across the developmental stages of D. cingulatus that provides preliminary descriptive observations that may guide future functional and experimental investigations into microbiota-based pest management.

Animals↗
PubMedDate not supplied

Progress toward understanding follicle development in vitro: appearances are not deceiving.

The interactive factors that influence the developmental progress of a follicle and determine whether it will progress to ovulation or toward atresia, are highly complex. In vitro models are being developed that are intended to provide a simplified environment to facilitate understanding of the dynamics of the processes involved. The purpose of this overview is to evaluate progress to date and to focus attention on issues that need more careful consideration to improve the usefulness of the models. Basically, two approaches exist. One, attached follicle culture, employs either enzyme-digested or mechanically harvested follicles depending on the method but allows attachment of the follicles to the culture surface. This produces a rounded or flattened structure (depending on culture conditions) that is no longer an intact follicle. During this culture, the cells reorganize themselves, some remaining in contact with the oocyte and others attaching to the culture surface and proliferating. The other approach, intact 3-dimensional follicle culture, employs mechanically dissected preantral follicles that are cultured as free-floating intact structures. Intact follicle culture emulates the in vivo developmental pattern of the follicle more closely than a non-intact structure can, and thereby provides a favorable model to investigate the interaction between hormonal and paracrine factors in the development of the follicle in isolation from systemic effects. For example, intact follicle culture has begun to be used to investigate the local effects of several different steroids. In addition, the local effects of inhibin, activin, and follistatin and their interactions with locally produced growth factors and steroids as well as synergy with gonadotrophins are beginning to be investigated. In our laboratory, the focus is on the roles of gonadotrophins at different stages of follicle development, particularly the effect of FSH isoforms in modulating follicle development in vitro. Finally, an important issue that urgently needs to be addressed, for future studies of in vitro follicle development, is the rationalization and standardization of follicle culture conditions.

Activins↗