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PubMed2005

Localization of Apaf1 gene expression in the early development of the mouse by means of in situ reverse transcriptase-polymerase chain reaction.

Apoptosis is an essential ubiquitous process that controls the duration of the life span of cells, thus playing a crucial role in morphogenetic, histogenetic, and phylogenetic developmental processes. Apaf1 (apoptosis protease activating factor 1) is one of the central mediators of the intrinsic apoptotic pathway and a part of the apoptosome, which activates procaspase-3 and promotes cell death. Gene knockout of Apaf1 in mice leads to late embryonic lethality with malformations such as the persistence of interdigital webs and hyperplasia of brain and retina. Therefore, Apaf1 is generally believed to play a crucial role in developmental apoptosis and have a widespread expression. However, its pattern of expression in early development remains unknown. To specify whether Apaf1 indeed plays this key role, we investigated the pattern of gene expression for Apaf1 in mouse embryos on day 7, 9, and 12 of development. Our results show, that gene expression for Apaf1 first occurs within the embryo between day 7 and 9 of development, becoming more widespread toward day 12 and then includes structures, such as yolk sac, mesenchyme, cartilage, heart anlage, otic vesicle, peridermis, and anlagen of the spinal ganglia and vertebral bodies. Our results also show that gene expression for Apaf1 is not ubiquitous in early mouse development. This finding indicates that cell death processes are independent of or less dependent on Apaf1 during this time. Of interest, an active gene expression for Apaf1 is also present in organ anlagen such as heart or intestine, in which no obvious phenotype is seen after Apaf1 deletion. This finding suggests a possible role for Apaf1 in such anlagen as a putative alternative compensatory pathway, which could be switched on in the case of defects in the mediators that are normally involved in such organs.

Animals↗
PubMed2006

A Golgi-localized hexose transporter is involved in heterotrimeric G protein-mediated early development in Arabidopsis.

Signal transduction involving heterotrimeric G proteins is universal among fungi, animals, and plants. In plants and fungi, the best understood function for the G protein complex is its modulation of cell proliferation and one of several important signals that are known to modulate the rate at which these cells proliferate is D-glucose. Arabidopsis thaliana seedlings lacking the beta subunit (AGB1) of the G protein complex have altered cell division in the hypocotyl and are D-glucose hypersensitive. With the aim to discover new elements in G protein signaling, we screened for gain-of-function suppressors of altered cell proliferation during early development in the agb1-2 mutant background. One agb1-2-dependent suppressor, designated sgb1-1(D) for suppressor of G protein beta1 (agb1-2), restored to wild type the altered cell division in the hypocotyl and sugar hypersensitivity of the agb1-2 mutant. Consistent with AGB1 localization, SGB1 is found at the highest steady-state level in tissues with active cell division, and this level increases in hypocotyls when grown on D-glucose and sucrose. SGB1 is shown here to be a Golgi-localized hexose transporter and acts genetically with AGB1 in early seedling development.

Alleles↗
PubMed2004

Talent identification and early development of elite water-polo players: a 2-year follow-up study.

The processes of talent detection and early development are critical in any sport programme. However, not much is known about the appropriate strategies to be implemented during these processes, and little scientific inquiry has been conducted in this area. The aim of this study was to identify variables of swimming, ball handling and physical ability, as well as game intelligence, which could assist in the selection process of young water-polo players. Twenty-four players aged 14-15 years underwent a battery of tests three times during a 2-year period, before selection to the junior national team. The tests included: freestyle swim for 50, 100, 200 and 400 m, 100-m breast-stroke, 100-m 'butterfly' (with breast-stroke leg motion), 50-m dribbling, throwing at the goal, throw for distance in the water, vertical 'jump' from the water, and evaluation of game intelligence by two coaches. A comparison of those players eventually selected to the team and those not selected demonstrated that, 2 years before selection, selected players were already superior on most of the swim tasks (with the exception of breast-stroke and 50-m freestyle), as well as dribbling and game intelligence. This superiority was maintained throughout the 2 years. Two-way tabulation revealed that, based on baseline scores, the prediction for 67% of the players was in agreement with the final selection to the junior national team. We recommend that fewer swim events be used in the process of selecting young water-polo players, and that greater emphasis should be placed on evaluation of game intelligence.

Achievement↗
PubMed1998

Widespread programmed cell death in early developing chick optic tectum.

We demonstrate that widespread programmed cell death exists in proliferative regions of chicken optic tectum during early development using a sensitive fluorescent ISEL method (FISEL+) and antibody staining for an antigen in dying cells. Several developmental stages from embryonic day (E) 3 to E18 were examined. FISEL+-positive cells were rare before E7 and between E9 to E12. However, massive labeling was observed in the ventricular zone (VZ) between stages E7.5 and E8. At this time extensive cell migration is underway and many labeled cells were found not only in the VZ (premigratory cells) but also in the intermediate zone and tectal plate (migratory cells). Many labeled cells were also found in upper tectal laminae at late developmental stages (E15 and E18).

Animals↗
PubMed2006

Early development of zooxanthella-containing eggs of the corals Porites cylindrica and Montipora digitata: The endodermal localization of zooxanthellae.

We studied the early development of zooxanthellae-containing eggs of the scleractinian corals Porites cylindrica and Montipora digitata to elucidate how zooxanthellae become localized to the endoderm of planulae during the course of development. In both species, zooxanthellae were distributed evenly in the oocytes and delivered almost equally to the blastomeres during cleavage. In P. cylindrica, gastrulation occurred via delamination or ingression, and blastomeres containing zooxanthellae dropped into the blastocoel during gastrulation. Thus, zooxanthellae were restricted to the endodermal cells at the gastrula or early planula stage in P. cylindrica. In M. digitata, gastrulation occurred by a combination of invagination and epiboly to form a somewhat concave gastrula. Zooxanthellae were present in both endodermal and ectodermal cells of early planulae, but they disappeared from the ectoderm as the planulae matured. In our previous study on two species of Pocillopora, we found that zooxanthellae were localized in eggs as well as in embryos, and that blastomeres containing zooxanthellae later dropped into the blastocoel to become restricted to the endoderm (Hirose et al., 2000). The timing and mechanism of zooxanthella localization and types of gastrulation differed among species belonging to the three genera. These results suggest that zooxanthella localization in the embryos reflects the timing of the determination of presumptive endoderm cells and/or specificity of zooxanthellae toward presumptive endoderm cells.

Animals↗
PubMed1990

Sex steroid profiles of coho salmon (Oncorhynchus kisutch) during early development and sexual differentiation.

Sex steroids were measured by radioimmunoassay in whole-body extracts of coho salmon, Oncorhynchus kisutch, during early development and sexual differentiation. Profiles were developed for fish from the time of fertilization until 87 days postfertilization (dpf) for six steroids: testosterone (T), 11-ketotestosterone (KT), androstenedione (A), progesterone (P4), 17 alpha-hydroxy-20 beta-dihydroprogesterone (DHP), and 17 beta-estradiol (E2). Ovarian fluid was also examined for steroid content. Steroid profiles of unfertilized eggs essentially paralleled those of ovarian fluid. In one experiment, steroids in developing embryos declined precipitously after fertilization until 30 dpf; at hatching, all steroids increased slightly and then declined during yolk sac absorption. Results from a second experiment basically supported those of the first except that only testosterone increased at the time of hatching. Bimodality was evident in the data on steroid levels for fish collected between 42 and 56 dpf and again after 87 dpf. The hormone levels generally decreased or remained constant after the onset of exogenous feeding. Histological analyses during the first experiment showed the presence of undifferentiated gonads between hatching and 70 dpf, but by 77 dpf ovarian development was evident. In the second experiment, in which fish were more frequently sampled for histological analysis, undifferentiated gonads were present from hatching to 59 dpf. Development of oogonia was observed between 66 and 73 dpf and by 75 dpf ovarian development could be easily discerned. The sex of fish sampled at 101 dpf was determined by examining gonadal morphology, and steroid levels of those fish were determined. A sexual dimorphism was apparent in levels of T, KT, and A, but not of DHP or E2. The dynamics of steroid content of developing coho salmon at hatch, coupled with their bimodal distributions during yolk sac absorption, may suggest a role of sex steroids in the process of sexual differentiation apparent later in development. Changes in whole-body steroid levels at hatch may also be indicative of the onset of sexual differentiation even though no signs of gondal differentiation were histologically discernible at that time.

Androstenedione↗
PubMed2006

Expression pattern of three putative RNA-binding proteins during early development of the sea urchin Paracentrotus lividus.

We report the expression patterns of three transcripts encoding RNA-binding proteins during early development of the Mediterranean sea urchin Paracentrotus lividus. Two of these genes encode KH-domains RNA-binding proteins closely related to the vertebrate neuro-oncological ventral antigen 1 (Nova) and RING Finger and KH-domain (RKHD). The third encodes the sea urchin ortholog of the polypyrimidine tract binding protein (PTB). Zygotic expression of nova and rkhd starts at mesenchyme blastula stage and is restricted to the presumptive endoderm territory. During gastrulation, expression of nova is restricted to the midgut and hindgut, while expression of rkhd become more complex and includes the foregut and hindgut territories as well as previously unknown territories within the ectoderm. PTB is first expressed ubiquitously but starting at the late gastrula stage, then PTB transcripts become highly enriched in the foregut and oral ectoderm. We further report that expression of nova and rkhd in the endomesoderm is under the control of the Wnt/beta-catenin pathway and occurs in a cell-autonomous manner while expression of rkhd and PTB in the oral ectoderm is regulated by Nodal signaling.

Amino Acid Sequence↗
PubMed1999

Effects of gonadal steroids on the GABA and glutamate contents of the early developing tilapia brain.

The effects of gonadal steroids on the gamma-aminobutyric acid (GABA) and glutamate (Glu) contents of the early developing brain were investigated. Seven-day-old (7 days post-hatch) tilapia were divided into three groups which were continuously treated with 100 mg/kg diet 17beta-estradiol (E2), 100 mg/kg diet methyltestosterone (MT), and a normal diet, respectively. Until 10, 20, and 30 days old, the GABA and Glu contents of the brains were detected by HPLC-ECD. The brain GABA and Glu contents, before 30 days old, significantly increased with age. These results demonstrate that before 30 days old is a developing period of both GABA and Glu systems in the tilapia brain. During this period, both E2 and MT have a facilitative effect on the GABAergic and Gluergic system during a restricted effective period.

Animals↗
PubMed2006

Parental attachment, parental control, and early development of alcohol use: a longitudinal study.

The authors explored the predictive influence of both parental attachment and parental control on early onset of alcohol consumption in adolescence by use of a longitudinal sample of 1,012 young adolescents. Whether the relationship between parental control and adolescents' drinking is moderated by parental attachment was also examined. Consistent with other studies, attachment and strict control were cross-sectionally related to adolescents' alcohol use at all 3 measurements. However, the longitudinal results of structural equation modeling analyses suggest that a good attachment relationship between parent and child does not prevent adolescents from drinking. In addition, strict control was related to lower engagement in alcohol use. Furthermore, with regard to the moderating effect, parental attachment did not moderate longitudinally the association between parental control and an early development of alcohol use. Implications for further research are discussed.

Adolescent↗
PubMed1999

Interactions between nerve growth factor binding and estradiol in early development of the zebra finch telencephalon.

The zebra finch telencephalon exhibits rapid and substantial development in the first few weeks after hatching. In parallel, the rate of estradiol synthesis is very high in the zebra finch forebrain, and estradiol can have potent neurotrophic effects in specific telencephalic regions, including those that control the learning and production of song. In an attempt to elucidate mechanisms regulating telencephalic development, potentially including a role for the large capacity for estrogen production, (125)I-nerve growth factor (NGF) binding was measured in homogenates of telencephalon from zebra finches age 3, 15, 30, 60, and 120 days. The highest density of low- and high-affinity (125)I-NGF binding sites was observed in 3-day-old finches. Using an aromatase inhibitor, Fadrozole, to reduce estradiol levels in 1 to 4-day-old zebra finches significantly decreased both high- and low-affinity (125)I-NGF binding sites. Conversely, treating adult or 8 to 14-day-old hatchlings with estradiol increased high-affinity (125)I-NGF binding sites. These results are consistent with the hypothesis that estradiol influences the level of NGF receptors, and suggest one mechanism through which the steroid could affect brain development. The data also indicate that estradiol and NGF activity may be important for very early development of the telencephalon.

Age Factors↗
PubMedDate not supplied

The early development of muscle spindle in human foetus.

The normal development of muscle spindles has been carefully described in a variety of species but only a few attempts were made to study the embryological development of the muscle spindle in humans. Most of the studies aimed to define the early development of muscle spindle in human foetuses, stated the begin of this process at the 11th week of intrauterine life, when the formation of a network of very fine nerve fibres with enlargements and ringle around developing muscle cells occur. In the present study we tried to document the probably earliest time of appearance of muscle spindles in the skeletal muscle of human foetuses. To this aim we examined fragments of deltoid and gastrocnemius muscles removed from human foetuses at the 9th and 10th week of gestation by using the light microscope technique. Data collected in muscle specimens at the 9th and 10th week of gestation showed the presence, at this time, of a structure with features clearly different from that of the adjacent muscular areas. This structure consists in a number of flat mesenchymal cells surrounding and forming several layers around a bundle of myoblasts smaller and lesser differentiated than the muscle cells located around and it is in close relationship with nervous fibres. These morphological findings might allow to identify the earliest stage of muscle spindle formation in human species.

Gestational Age↗
PubMed1988

The early development of subcortical projections to presumptive somatic sensory-motor areas of neocortex in the North American opossum.

We have studied the early development of subcortical projections to presumptive somatic sensory-motor areas of neocortex in the North American opossum Didelphis virginiana. The opossum is born in a very immature state, 12-13 days after conception, and climbs into an external pouch where it is available for experimental manipulation. Using the retrograde transport of wheat germ agglutinin conjugated to horseradish peroxidase, we have obtained evidence that axons from the dorsal raphe and superior central nuclei, the substantia nigra, the locus coeruleus and the parabrachial nuclei reach presumptive somatic sensory-motor areas of neocortex by at least postnatal day (PND) 10. Axons showing serotonin-like immunoreactivity, presumably from the dorsal raphe and/or superior central nuclei, and axons containing tyrosine hydroxylase immunoreactivity, presumably from the substantia nigra and/or locus coeruleus, are present in the same areas at birth or shortly thereafter. Thalamic axons do not grow into comparable areas of neocortex until after PND 10. Such axons reach the subplate region of ventrolateral neocortex first and then proceed dorsomedially; by estimated PD (EPND) 21, they are present in presumptive layers I, V and VI, but they do not innervate an identified layer IV until EPND 48. The developmental sequences suggested by our study are compared with those reported for other species and are discussed in light of their importance in the formation of major sensory and motor circuits.

Animals↗
PubMed1989

Strain differences in the early development of the thymus-dependent cells: precocity of T lineage cells in AKR mice as compared to those in C3H mice.

Early development of T lineage cells were compared between AKR and C3H mice by using two experimental strategies--neonatal thymectomy (NTx) and bone marrow transplantation (BMT)--between these two strains of mice. After NTx, AKR mice developed less wasting disease and showed better maintenance of several T cell functions. In addition, the response of neonatal spleen cells to PHA and ConA was much greater in AKR mice than in C3H mice. Further, when AKR mice were used as recipients of BMT, cell numbers recovered from thymuses between 2 and 7 weeks after reconstitution were consistently much greater (about 10 times greater) than those from chimeras where C3H mice were used as recipients, regardless of the donor strains of bone marrow cells. However, 4 weeks after BMT the proliferative responses to ConA were consistently higher in the donor-derived thymocytes from chimeras where AKR mice were used as bone marrow donors than in those from chimeras in which C3H were donors. The present findings suggest that these differences may be attributed to characteristics of recipient microenvironment (e.g., thymic stroma) which maintain developing thymocytes and supply them to the peripheral lymphoid tissue. Alternatively the differences may to some degree also be attributable to characteristics of the thymic progenitors themselves, which may determine the rates of maturation of thymocyte functions.

Animals↗
PubMedDate not supplied

[Aspartate- and alanine-aminotransferase in early development of keta].

We studied the activities of the marker enzymes of physiological state and adaptive reactions, aspartate and alanine aminotransferases, in early development of the keta Oncorhynchus keta. Aspartate aminotransferase with pH optima 6.8, 7.0, 7.6, and 8.0 and alanine aminotransferase with pH optima 7.0, 7.4, 7.6, 7.8, 8.0, and 8.2 were found in the eggs, larvae, and fry. The succession of enzymes with different pH takes place during ontogenesis, as well as stage specific changes in their activity. The maximum enzymatic activity was recorded in the larvae during their rise for "afloat." A correlation was established between the dynamics of enzymatic activity and soluble nitrogen and amine nitrogen contents.

Alanine Transaminase↗
PubMed1985

Acetylcholinesterase (AChE) and pseudocholinesterase (BuChE) activity distribution pattern in early developing chick limbs.

The distribution of acetylcholinesterase (AChE) and pseudocholinesterase (BuChE) activities was studied by histochemical, quantitative and electrophoretical methods during the early development of chick limbs, from stage 16 to stage 32 H.H. (Hamburger & Hamilton, 1951). By quantitative methods, true AChE activity was found, and increased about threefold during the developmental period, together with a smaller amount of BuChE which increased more rapidly in comparison with the AChE activity from stage 25 to 32 H.H. Cholinesterase activity was histochemically localized mainly in interacting tissues, such as the ectoderm (including the apical ectodermal ridge) and the underlying mesenchyme. True AChE was histochemically localized around the nuclei and on the plasma membrane of ectodermal (including AER) and mesenchymal cells, and at the plasma membrane of mesenchymal cell processes reaching the basal lamina between the ectoderm and the mesenchyme. AChE together with BuChE activity was found in the basal lamina between the ectoderm and the mesenchyme, in underlying mesenchymal cells and in deeper mesenchymal cells, especially during their transformation into unexpressed chondrocytes. During limb morphogenesis, the cellular and regional localization of the enzyme activities showed variations depending on the stage of development and on the occurrence of interactions. The possibility of morphogenetic functions of the enzyme id discussed.

Acetylcholinesterase↗
PubMed2003

Morphology of early developing oligodendrocytes in the ventrolateral spinal cord of the chicken.

The oligodendroglial population includes Type I and II cells related to several thin axons, Type III cells with a few processes in relation to relatively thick axons and Type IV cells related to a single thick axon. This structural diversity of oligodendrocytes is accompanied by a molecular heterogeneity. In the chicken spinal cord, oligodendrocytes have begun to contact axons at embryonic day (E)10 and compact sheaths have appeared by E12. At the latter stage, most sheath-forming oligodendrocytes contact more than one axon. At E15, however, each sheath-forming cell seems to have developed a Schwann cell-like anatomy, being related to a single axon. Based on these findings, the present study examines more thoroughly the anatomy of early developing oligodendrocytes in the chicken spinal cord. Examination of slices immunostained with antibodies against the oligodendroglial marker O4 showed that a few positive cells are present at E6, after which the occurrence increases with age. At E12 most immunostained cells have two or more processes. At E15 however, dye-injected oligodendrocytes have developed a Type IV structure. Between E12 and E15, mean sheath length increases about 4x, from 50 microm to over 200 microm, while the length of the spinal cord increases 36% only. This indicates that early oligodendrocytes in chicken white matter develop a Type IV anatomy between E12 and E15 through an elimination of sheaths.

Animals↗
PubMed1993

Early development of the pineal photoreceptors prior to the retinal differentiation in the embryonic rainbow trout, Oncorhynchus mykiss (Teleostei).

The development of the pineal and retinal photoreceptors in the embryonic rainbow trout, Oncorhynchus mykiss was investigated by means of light and electron microscopy. The pineal photoreceptors endowed with photoreceptive outer segments and signal-transmitting synapses appeared first 15 days after fertilization, and well developed by 21 days. In contrast, the retinal photoreceptors appeared as late as 27 days after fertilization (1 day before hatching). This temporal disparity in photoreceptor development has been compared with the photoperiodic formation of otolith increments, which is initiated during an early developmental stage lacking retinal photoreception. It has been suggested that the early development of pineal photoreceptors may be involved in light-dark recognition, establishment of the diel and circadian rhythms, and entrainment to the environmental photoperiod in the embryonic rainbow trout.

Animals↗