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Results for “Developmental stage”

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PubMed1999

Molecular identification of developmental stages in Opecoelidae (Digenea).

Nuclear ribosomal DNA sequences represent a useful tool for distinction of poorly differentiated developmental stages, such as trematode cercariae or metacercariae. Here, the complete internal transcribed spacer region of the ribosomal DNA (ITS 1 + 5.8S + ITS 2) was sequenced for 29 specimens of the digenean family Opecoelidae, including 16 adult specimens and 13 undescribed larval stages (nine cercariae and four metacercariae) occurring in various marine host organisms. Six cercariae and three metacercariae were found to match their corresponding adult form. This work also revealed that cercariae of the same species are able to infect more than one gastropod host species, suggesting that the specificity for the first intermediate host within the Digenea may be lower than previously thought.

Animals↗

PubMed2006

Identification of related QTLs at late developmental stage in rice (Oryza sativa L.) under two nitrogen levels.

QTL underlying related traits at the late developmental stage under two different nitrogen levels were investigated in rice using a population of chromosome segment substitution lines (CSSL) derived from a cross between Teqing and Lemont. A total of 31 QTLs referring 5 traits, that is, plant height (PH), panicle number per plant (PN), chlorophyll content (CC), shoot dry weight (SDW) and grain yield per plant (YD), were detected. Under normal N level, 3 QTLs were detected for each trait, while under low N level, 5, 4, 5 and 2 QTLs were detected for PH, PN, CC and SDW respectively. Most of the QTLs were located on chromosome 2, 3, 7, 11 and 12. QTLs controlling different traits or the same trait under different N levels were mapped on the same or adjacent intervals, forming several clusters in rice chromosomes. More than two traits were controlled by QTLs on one of four intervals (RM30-RM439, RM18-RM478, RM309-RM270, and RM235-RM17), suggesting that there were some pleiotropic effects. It was supposed that some QTLs only detected at low N level might be associated with the ability to tolerate the low N stress in rice.

Chlorophyll↗

PubMedDate not supplied

A developmentally staged curriculum for teaching self-care to the child with insulin-dependent diabetes mellitus.

A developmentally staged curriculum has been designed to teach children with insulin-dependent diabetes mellitus about their disorder and its care within an organized program of ongoing ambulatory medical care. A preliminary evaluation of the teaching program based on this curriculum indicates that self-care skills are mastered but that the implementation of self-monitoring aspects decreases during adolescence. A survey of a sampling of participants indicates that interest in the program also declines with adolescence. However, the majority had positive responses at all ages and all children and adolescents had positive responses to the experience of being with diabetic peers. The curriculum is presented to help organize the appropriate teaching of diabetes care to children and adolescents.

Age Factors↗

PubMed1994

Biochemical characterization of the developmental stage- and tissue-specific erythroid transcription factor, NF-E4.

Analysis of the nuclear factors responsible for erythroid gene regulation has led to the cloning of several transcriptional regulatory proteins with clear lines of evidence suggesting or demonstrating their roles in tissue-specific gene expression. However, the erythroid cell lineage-restricted proteins that have been characterized to date do not differ significantly in activity during the distinct developmental stages of erythropoiesis, a characteristic that might be expected for a nuclear factor that actively participates in the differential regulation of various alpha- or beta-type globin genes (called globin gene switching) at distinct stages of embryonic development. We reported previously the identification of such a differentially expressed DNA binding activity, which appeared to be present in mature definitive (adult) erythroid cells but absent in immature definitive or primitive (embryonic) erythroid cells. Here we detail the biochemical properties of this erythroid tissue- and developmental stage-specific DNA binding activity (called nuclear factor-erythroid 4; NF-E4), which contains characteristics of a molecule that may be intimately involved in globin gene switching.

Animals↗

PubMed1994

Differential effects of transforming growth factor-beta 1 on distinct developmental stages of murine megakaryocytopoiesis.

The effect of transforming growth factor-beta 1 (TGF beta 1) on three developmental stages of megakaryocytopoiesis was investigated. Using a murine bone marrow agar culture system, titrated doses of TGF beta 1 were added to cultures assaying primitive high proliferative megakaryocyte progenitors, committed megakaryocyte precursors, and nondividing, endoreduplicating megakaryocytes. The growth of high proliferative megakaryocyte colony-forming cells (HPP-CFU-Mk) that require the growth factors interleukins-1, 3 and 6 (IL-1 + IL-3 + IL-6) for colony detection was abrogated by the addition of 1 ng TGF beta 1/ml. The sensitivity of committed megakaryocyte progenitors (colony-forming unit-megakaryocyte, CFU-Mk) to TGF beta 1 depended on the growth factor combination. TGF beta 1 (1 ng/ml) completely inhibited megakaryocyte colony formation from CFU-Mk only in cultures stimulated by low doses of IL-3. TGF beta 1 (> 10 ng/ml) could only marginally inhibit megakaryocyte colony formation generated in the presence of either high doses of IL-3 or the combination of low dose IL-3 + IL-6. TGF beta 1 inhibited both IL-3-dependent and IL-6-dependent megakaryocyte growth but tenfold higher doses of TGF beta 1 were required to inhibit growth generated by the combination of IL-3 + IL-6. The data showed that the capacity of TGF beta 1 to inhibit distinct differentiation stages of the megakaryocytopoietic lineage depended on the concentration and combination of growth factors involved.

Animals↗

PubMed1988

Transitional changes in arachidonic acid metabolism by bovine embryos at different developmental stages.

In order to determine the profile of arachidonic acid (AA) metabolites synthesized by bovine embryos during early developmental stages, embryos collected from superovulated beef cattle (days 6 through 17) were incubated with AA and its metabolites were analyzed by high performance liquid chromatography and radioimmunoassay (RIA). Embryos harvested and cultured before day 12 of the estrous cycle metabolized AA primarily to prostaglandin E2 (PGE2), whereas, those harvested on day 13 of the cycle metabolized AA to both PGE2 and PGF2 alpha. Furthermore, embryos collected after day 15 of the cycle metabolized AA to PGI2 in addition to PGE2 and PGF2 alpha. In view of the luteotropic properties that have been attributed to PGE2 and the vasodilatory effect of PGI2, this transitional change in prostaglandin synthesis during early stages of embryonic development may be a part of the mechanism by which the embryo exerts a luteotropic effect leading to maternal recognition of pregnancy and by which the conceptus begins preparing for subsequent implantation.

Animals↗

PubMed1988

Analysis in serum-free culture of the targets of recombinant human hemopoietic growth factors: interleukin 3 and granulocyte/macrophage-colony-stimulating factor are specific for early developmental stages.

We have used a serum-free culture system for enriched human hemopoietic progenitors to analyze the developmental stages and lineage specificities of the human hemopoietic colony-stimulating factors. None of the individual factors alone efficiently supported hemopoietic colony formation. Neither interleukin 3 nor granulocyte/macrophage-colony-stimulating factor alone or in combination effectively supported proliferation of progenitor cells. However, when combined with granulocyte-colony-stimulating factor or erythropoietin, these factors yielded neutrophil colonies or erythroid bursts, respectively. Serial observations of interleukin 3-supported cultures revealed sequential emergence and subsequent degeneration of clusters of cells. These observations suggest that the primary targets of interleukin 3 and granulocyte/macrophage-colony-stimulating factor are multipotent progenitors at the early stages of development rather than cells in the terminal process of maturation.

Adult↗

PubMed1994

Influence of the developmental stage and the equilibration time on the outcome of ultrarapid cryopreservation of mouse embryos.

Mouse embryos of different developmental stages from 1- to 8-cell inclusive were ultrarapidly frozen in 0.25 ml French straws after various periods of equilibration (1, 3, 5 and 9 min) in freezing-buffer containing 3.5 M dimethylsulphoxide (DMSO), 0.25 M sucrose, and 20% fetal calf serum (FCS) in phosphate buffered saline (PBS). After thawing in a 37 degrees C waterbath and dilution for 5 min in 0.25 M sucrose in PBS/FCS the embryos were cultured in Ham's F10 medium with 10% FCS (37 degrees C, 5% CO2, 95% humidity) for 4-6 days. The rates of expanded and hatching blastocysts were then evaluated and compared to the corresponding rates of non-frozen controls. Thus, for each cleavage stage, the optimal equilibration time was evaluated. It was 1 min for the 1-cell and 8-cell stages (32 and 81% blastocysts, respectively), and 3-5 min for the 2-cell (76 and 73%, respectively) and the 4-cell stage (88 and 87%, respectively). It is concluded that the ultrarapid freezing method described provides satisfactory results for all tested cleavage stages, but not for the 1-cell stage.

Animals↗

PubMed1985

Hemopoietic differentiation potential of cultured lateral plate mesoderm explanted from Rana pipiens embryos at successive developmental stages.

Ventral blood island mesoderm and dorsal lateral plate mesoderm were removed from Rana pipiens embryos at successive developmental stages (stages 13-19; 50-118 h) and cultured as individual explants in serum-free medium. After 5-7 days, the cultures were harvested, and differential counts were made of Wright-Giemsa-stained cells. Ventral blood island explants gave rise to cells of the myeloid lineage, suggesting that ventral blood island mesoderm was committed to hemopoiesis at the time of explant. Although erythrocytes were present in the cultures, granulocytes and monocyte/macrophages predominated. This differentiation profile occurred without the addition of any exogenous humoral factors. Monocyte/macrophages and immature precursor cells exhibited recurring inverse fluctuations with respect to one another. In all cases examined, cultures of dorsal lateral plate mesoderm showed marginal hemopoietic cell differentiation, suggesting a requirement for exogenous humoral factors and/or cell-cell interactions. When viewed in the context of previous studies from our laboratory, these results demonstrate that, in the amphibian embryo, there are two sources of hemopoietic stem cells separated both in space and time.

Animals↗

PubMed1992

Glutathione transferase isoenzymes from Bufo bufo embryos at an early developmental stage.

Six forms of glutathione transferase (GST) were resolved from the cytosolic fraction of Bufo bufo embryos at developmental stage 4 by GSH-Sepharose affinity chromatography followed by f.p.l.c. chromatofocusing in the 9-6 pH range. They have apparent isoelectric points at pH 8.37 (GST I), 8.22 (GST II), 8.10 (GST III), 7.84 (GST IV), 7.37 (GST V) and 7.12 (GST VI), and each displayed an apparent subunit molecular mass of 23 kDa by SDS/PAGE. The Bufo bufo embryo enzymes showed very similar structural, catalytic and immunological properties, as indicated by their substrate-specificities, inhibition characteristics, c.d. spectra, h.p.l.c. elution profiles and immunological reactivities, as well as by their N-terminal amino acid sequences. Although Bufo bufo embryo GSTs do not correspond to any other known GSTs, the results of our experiments indicate that amphibian GSTs could be included in the Pi family of GSTs. This conclusion is supported by the analysis of c.d. spectra, and by the fact that mammalian Pi class GSTs and amphibian GSTs showed about 80% identity in their N-terminal amino acid sequences. Furthermore, antisera prepared against Bufo bufo GST III cross-reacted in immunoblotting analysis with Pi class GSTs, and vice versa.

Amino Acid Sequence↗

PubMed1995

[The question of pathogenesis of parasitic castration in snails infected with developmental stages of digenetic trematodes].

In the article several models of pathogenesis of parasitic castration of snails infected with developmental stages of digenetic trematodes are presented. Some aspects of mechanical and chemical damage of the gonad and changes in tissues of this organ, caused by its starvation--developing as a consequence of competition between the host and its parasites, are discussed. Particular attention was paid to potential effect of the parasitic larvae on physiology of the hormonal system of the host.

Animals↗

PubMed1978

Template activity for histones of poly(A)-minus RNA fraction from different developmental stages of Artemia salina embryos.

Template activity for histones of RNA fractions derived from Artemia salina embryos at different developmental stages were measured in a Krebs ascites cell-free system. Appreciable amounts of acid-soluble polypeptides comigrating with Hela cell histone markers on acrylamide gel electrophoresis were detected only when RNA fractions from nauplii were used. Tryptic peptide analysis by high voltage electrophoresis of the translational products had a pattern qualitatively similar to that of in vivo labeled histone markers from Hela.

Animals↗

PubMedDate not supplied

High performance liquid chromatography analysis of the furanochromones khellin and visnagin in various organs of Ammi visnaga (L.) Lam. at different developmental stages.

The content of the furanochromones khellin and visnagin, in the organs of Ammi visnaga (L.) Lam. at different developmental stages, has been examined. Determinations have been performed by means of a high performance liquid chromatography (HPLC) technique which allows both the separation and the quantitative determination of these chromones. Unripe fruits are the richest in both chromones, but the collection of ripe dry fruits--as it occurs in Egyptian folk-medicine--seems more reasonable because they might not undergo degradation processes during desiccation and storage.

Chromatography, High Pressure Liquid↗

PubMed1989

[Tegumental ultrastructures of Paragonimus iloktsuenensis according to the developmental stages].

A scanning electron microscopic study was performed to observe the tegumental ultrastructures of Paragonimus iloktsuenensis according to its developmental stages. The metacercariae were obtained from the liver of the brackish water crab, Sesarma dehaani. Juvenile and adult P. iloktsuenensis were recovered from the experimental rats on 2, 4 and 8 weeks after infection. The findings were summarized as follows: 1. The excysted metacercariae were characteristically gourd-shape, with their whole body surface beset with numerous spade-shape spines. The large, type II sensory papillae (non-ciliated round swellings) were arranged along the rim of the oral and ventral suckers, 11-12 and 6-8 in numbers respectively. 2. Two-week old juvenile worms, recovered chiefly from the liver of the experimental rats, were slender in body shape, with their ventral sucker near the anterior one-third level. The distribution of tegumental spines was less dense than in the excysted metacercariae. The spines were with 1-2 pointed tips and 3-4 longitudinal splits. Numerous ciliated knob-like, type I papillae were observed in both sides of the oral sucker, and 6 large, type II papillae were arranged along the rim of the ventral sucker. 3. Four-week old worms, recovered from the thoracic cavity and/or lung parenchyme of the experimental rats, were thicker than wide in body configuration, and their ventral sucker was located near the anterior one-fourth level. The tegumental spines at ventral surface were grouped, each group with 3-5 aggregated ones. The type I and type II papillae (small-sized) were distributed chiefly around the rim of two suckers. 4. Adult (eight-week old) worms, recovered from the capsules in the lung parenchyme, were very stout, and covered densely with bearfoot-like spines. At dorsal surface, cobblestone-like cytoplasmic processes were well-developed, with many tegumental spines embedded in them. It was observed in this study that the tegument of P. iloktsuenesis continued to change and differentiate as the worms grew to be adults.

Animals↗

PubMed1994

Analysis of gene expression by tissue and developmental stage.

High-throughput sequencing of cDNAs from multiple tissue- and stage-specific libraries is an efficient method for characterizing gene expression by tissue and developmental stage. When combined with functional information derived from the systematic study of transcription factors, signal transducers, and other regulatory molecules in model systems, data from expressed sequence tag projects provide an increasingly detailed picture of gene expression and its regulation. Understanding this picture will require the development of highly sophisticated databases to organize and correlate these data.

Animals↗

PubMed1999

Growth and differentiation of cultured fetal hepatocytes isolated various developmental stages.

We examined the relationship between cell proliferation and differentiation of cultured rat fetal and newborn hepatocytes isolated from various developmental stages. The albumin production rate increased along with cell growth under in vitro culture and became maximal two days after the growth cessation. AFP was secreted by both fetal and newborn hepatocytes with growth ability. Furthermore, the responses to HGF addition in fetal hepatocyte cultures were observed in terms of growth stimulation and down-regulated of the Met receptor. We also studied the changes in RB and liver enriched transcription factors (C/EBPs) for investigating the mechanism underlying proliferation and differentiation of fetal hepatocytes. Western blot analysis of hepatocytes taken from various gestation stages of rat liver showed that the expression of RB and C/EBP beta increased as gestation stage proceeded. When RB antisense S-oligonucleotide was added to the culture medium, proliferation and AFP expression increased, while C/EBP alpha and albumin expressions decreased. These results indicated that the tumor suppressor gene product RB had a profound role not only in cell proliferation but also hepatocyte differentiation.

Albumins↗

PubMed2002

Millisecond by millisecond, year by year: normative EEG microstates and developmental stages.

Most studies of continuous EEG data have used frequency transformation, which allows the quantification of brain states that vary over seconds. For the analysis of shorter, transient EEG events, it is possible to identify and quantify brain electric microstates as subsecond time epochs with stable field topography. These microstates may correspond to basic building blocks of human information processing. Microstate analysis yields a compact and comprehensive repertoire of short lasting classes of brain topographic maps, which may be considered to reflect global functional states. Each microstate class is described by topography, mean duration, frequency of occurrence and percentage analysis time occupied. This paper presents normative microstate data for resting EEG obtained from a database of 496 subjects between the age of 6 and 80 years. The extracted microstate variables showed a lawful, complex evolution with age. The pattern of changes with age is compatible with the existence of developmental stages as claimed by developmental psychologists. The results are discussed in the framework of state dependent information processing and suggest the existence of biologically predetermined top-down processes that bias brain electric activity to functional states appropriate for age-specific learning and behavior.

Adolescent↗

PubMed1982

Intracellular plasma proteins in human fetal choroid plexus during development. I. Developmental stages in relation to the number of epithelial cells which contain albumin in telencephalic, diencephalic and myelencephalic choroid plexus.

The developmental stages of telencephalic, diencephalic and myelencephalic choroid plexuses in the human fetus and the morphology of choroid plexus epithelial cells in the various plexuses in different development stages were described on basis of PAS- and toluidine blue-stained material. Six different cell types were identified in various combinations in 4 different stages (I-IV). The number and distribution of albumin-containing epithelial cells in various plexuses in the different stages of development were investigated by indirect immunoperoxidase technique. Albumin-containing cells did not belong to a single cell type. The telencephalic plexus exhibited a staining pattern for albumin which was different from that of the diencephalic and myelencephalic plexuses. In the telencephalic plexus positive epithelial cells were frequent in stage I, whereas only a few positive cells were present in stage II and III. In contrast, 30-40% of the epithelial cells in both diencephalic and myelencephalic plexuses in stage I, II and III showed a positive staining reaction. Later in gestation less than 10% were positive. It is suggested that a main function of the diencephalic and myelencephalic plexuses early in gestation is associated with protein transport rather than with glycogen synthesis and storage which might be a major function of the telencephalic plexus.

Cell Differentiation↗