PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Developmental stage”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed1998

Variation in acid hydrolase enzyme titers in different developmental stages of Aedes togoi.

Genetic mechanisms of filarial nematode susceptibility were studied in Aedes togoi. Acid hydrolases may play an important role in this process, including humoral or cell-mediated defenses. Levels of acid phosphatase, alpha-glucosidase, beta-glucuronidase, and N-acetyl-beta-glucosaminidase were determined for 1st- and 4th-instar larvae, male and female pupae, and 1- and 7-day-old adults using fluorometric and colorimetric assays. Acid phosphatase activity was highest in 1-day-old adults, moderate in larvae and pupae, and lowest in 7-day-old adults. Female 7-day-old adults had significantly higher levels than males of the same age. Moderate levels of alpha-glucosidase were found in larvae, with progressive increases in activity from pupae to 7-day-old adults. Levels in male pupae and 1-day-old males were higher than in females, but activity was twice as high in 7-day-old females. Activity of beta-glucuronidase was greater in adults, with females showing a 2-fold higher level than males at 7 days. In contrast, N-acetyl-beta-glucosaminidase activity was highest in 1st- and 4th-instar larvae and 1-day-old males and females. Activity also was significantly higher in male pupae, slightly greater in 1-day-old males, but twice as high in 7-day-old females when compared to males of the same age. Results showed significant changes and variation in acid hydrolase enzyme titers in the different life stages of Ae. togoi. These and other specific acid hydrolases could prove effective in monitoring biochemical and genetic changes in mosquito populations.

Aedes↗
PubMed1985

Localization of mRNAs in mouse testes by in situ hybridization: distribution of alpha-tubulin and developmental stage specificity of pro-opiomelanocortin transcripts.

Gene expression of mouse testicular germ cells and surrounding somatic cells during spermatogenesis was examined by RNA:cDNA hybridization in situ and concomitant Northern and dot blot analysis. Particular attention was paid to obtaining fixation and hybridization procedures for use with mouse testes to accomplish sensitive and precise localization with the in situ technique. alpha-Tubulin mRNAs were localized in virtually all testis cell types. In elongating spermatids, a unique labeling pattern was visualized; possibly corresponding to the position of the asymmetrically displaced cytoplasm. Pro-opiomelanocortin (POMC) transcripts in the adult mouse testis detected by Northern blot analysis were shown to be of a smaller size (approximately 600-800 nt) than the pituitary POMC transcripts, similar to what has been reported recently for POMC expression in the rat testis and mouse Leydig cell lines. Localization of POMC mRNAs by in situ hybridization was primarily to Leydig cells, although some labeling of spermatogonia and spermatocytes within the seminiferous epithelium was detected. A cellular or developmental specificity of the pattern of POMC localization was observed: obvious labeling of Leydig cells was limited to interstitial regions which were surrounded completely or in part by tubules in stages IX to XII of the cycle of the seminiferous epithelium.

Animals↗
PubMed2003

Expression of KS-type dehydrins is primarily regulated by factors related to organ type and leaf developmental stage during vegetative growth.

The expression of a gene, designated as DHN10, was analyzed at the protein level in two Solanum species. The DHN10 protein displays some consensus amino acid sequences of dehydrins, termed K- and S-segments. Unlike most dehydrins, both segments occur only in single copies in the DHN10 sequence and the S-segment is at a C-terminal position. Database searches revealed that KS-type dehydrins constitute a specific subclass distributed in dicotyledons and monocotyledons. In Solanum tuberosum L. plants, a high DHN10 abundance was observed under control conditions, particularly in flowers, stems, tubers and young developing leaves. In other Solanaceae and in barley ( Hordeum vulgare L.), the amount of DHN10 was much more elevated in young leaves than in old leaves. DHN10 abundance was investigated in two Solanum species subjected to low temperature or to drought. Under stress conditions, we observed substantially higher protein levels only in mature expanded leaves. These findings clearly indicate that KS-type dehydrins are present at a high level in the absence of stress during vegetative growth and that their expression is primarily regulated by factors related to organ type and to leaf development stage. A potential role for the DHN10 dehydrin during plant development and in tolerance to environmental stress is discussed.

Amino Acid Sequence↗
PubMed1988

Calmodulin in normal and cystic fibrosis human intestine at different developmental stages.

Calmodulin concentrations and localisation have been analysed as a function of development in human intestinal epithelial cells from normal and cystic fibrosis individuals. In normal fetuses up to eight weeks of gestation intestinal epithelial cells which were still undifferentiated were not immunoreactive and their calmodulin content was low. From eight weeks onwards there was a significant overall increase in calmodulin content concomitant with its segregation to the apical side of epithelial cells. At 14 weeks of gestation calmodulin concentrations and localisation closely resembled those of adults. The developmental pattern of calmodulin appeared to parallel the morphological and functional maturation of brush borders which occurs during the first trimester of pregnancy. In the intestinal epithelial cells from a 19 weeks cystic fibrosis fetus and a cystic fibrosis newborn infant neither calmodulin concentration, nor its localisation were affected. Similarly, brush border calmodulin binding proteins and enzymatic activities were similar in normal subjects and the cystic fibrosis intestine.

Adult↗
PubMed2002

Retinoic acid synthesis in the postnatal mouse brain marks distinct developmental stages and functional systems.

Retinoic acid (RA) affects development and function of the brain, but little is known about how much is made locally and where it is distributed. To identify RA-sensitive neural processes, we mapped the RA-synthesizing retinaldehyde dehydrogenases (RALDHs) during postnatal brain formation of the mouse. High and stable RALDH expressions mark the basal ganglia, olfactory bulbs, hippocampus and auditory afferents as major sites of RA actions in the functional brain. During the early postnatal period, transient and very high RALDH3 expressions distinguish two developmental events: (i) the colonization of the nucleus accumbens and the olfactory bulbs by neuronal precursors and (ii) the maturation of selected parts of the cerebral cortex. In the cortex, RALDH3 is transiently activated in postmigratory layer II/III neurons during formation of their dendritic arbors and it is transported in their axons across the corpus callosum. RALDH3-expressing cortical regions include most of the limbic lobe, with strongest expression in the anterior cingulate cortex, medial and lateral secondary visual cortices, auditory cortical areas, the secondary motor cortex and some association areas. The transient cortical expression points to a brief RA-critical period during differentiation of the cortical network that serves in the coordination of sensory-motor activity with emotional and recently learned information.

Aldehyde Oxidoreductases↗
PubMed1998

Cytokines promote the survival of mouse cranial sensory neurones at different developmental stages.

To investigate when the neurotrophic cytokines ciliary neurotrophic factor (CNTF), leukaemia inhibitory factor (LIF), oncostatin-M (OSM), interleukin-6 (IL-6) and cardiotrophin-1 (CT-1) act on developing sensory neurones and whether they co-operate with neurotrophins in regulating neuronal survival, we studied the in vitro trophic effects of these factors on two well-characterized populations of cranial sensory neurones at closely staged intervals throughout embryonic development. The cutaneous sensory neurones of the trigeminal ganglion, which show an early, transient survival response to BDNF and NT3 before becoming NGF-dependent, were supported by CNTF, LIF, OSM and CT-1 during the late fetal period, several days after the neurones become NGF-dependent. At this stage of development, these cytokines promoted the survival of a subset of NGF-responsive neurones. The enteroceptive neurones of the nodose ganglion, which retain dependence on BDNF throughout fetal development, were supported throughout their development by CNTF, LIF, OSM and CT-1, and displayed an additional survival response to IL-6 in the late fetal period. These findings indicate that populations of sensory neurones display different developmental patterns of cytokine responsiveness and show that embryonic trigeminal neurones pass through several phases of differing neurotrophic factor survival requirements.

Aging↗
PubMed2002

Regulation of fetal versus embryonic gamma globin genes: appropriate developmental stage expression patterns in the presence of HS2 of the locus control region.

The gamma genes provide the major contribution to beta-like globin chain production in the fetal liver of humans. However, the expression of gamma genes in the fetus is a recent evolutionary trend seen only in the primate lineage. In a previous study, it was shown that galago and human gamma genes retain their characteristic stage-specific expression patterns in transgenic mice (galago gamma is expressed exclusively in the embryo, whereas human gamma is expressed in the fetus). In that experiment, human and galago gamma genes were linked to hypersensitive site 3 (HS3) of the locus control region. To rule out the possibility that HS3 is required for these differential expression profiles, additional transgenic lines were tested in which human or galago gamma genes were linked to HS2. Once again, the galago gamma gene was embryonic and the human gamma gene was fetal, indicating that the stage specificity of these genes is driven by elements located within the 4-kb fragments that contain the human and galago gamma genes proper.

Age Factors↗
PubMed2001

Localization of the initial developmental stages of Loma salmonae in rainbow trout (Oncorhynchus mykiss).

The intracellular microsporidian parasite Loma salmonae affects salmonids of the genus Oncorhynchus and is a significant cause of economic losses in pen-reared Chinook salmon (O. tshawytscha) in British Columbia. Loma salmonae infection is easily recognized by the xenomas that form in the gills, but early stages of infection are difficult to detect in histologic sections. In situ hybridization (ISH), using an L. salmonae-specific digoxigenin-labeled single-stranded DNA probe, was used to detect the parasite during the early stages of infection. Loma salmonae was detected in the gut mucosal epithelium as early as 24 hours postexposure (PE), and it localized in the lamina propria of the intestine within 24 hours of infection. After the parasite was detected in the lamina propria, dividing merogonic stages in infected cells in the heart were detected by ISH as early as 2 days PE, providing the first evidence of parasitaemia and hematogenous distribution of this parasite in infected blood cells. The parasites inside the infected cells appeared to be undergoing merogony as they passed through the heart, indicating that proliferation may start at the site of infection, before the parasite arrives to the gills for their final developmental phase. This is the first time that L. salmonae passage through the intestinal wall and migration to the heart has been visualized; however, the identity of the cells harboring the parasite has yet to be determined.

Animals↗
PubMed2006

Differential expression of Paragonimus westermani eggshell proteins during the developmental stages.

Eggs of trematode parasites are comprised of numerous vitelline cells and one fertilized ovum, and are encapsulated within a protein shell provided by the vitellocytes. In this study, we isolated two full-length cDNA clones that showed substantial levels of sequence identity with trematode-specific eggshell precursor proteins from the human lung fluke, Paragonimus westermani. These cDNAs, designated Pw-Vit20 (868-bp-long) and Pw-Vit36 (883-bp-long), shared a 76% identity with one another at the nucleotide level, and each encoded a 261-amino acid (aa) polypeptide. The deduced aa sequences contained a N-terminal hydrophobic segment, as well as a sequence motif of Gly-Gly-Gly-Tyr-Asp-Asn/Thr-Tyr-Gly-Lys/Gln, which is highly homologous with the eggshell proteins of Fasciola hepatica. With the high frequencies of tyrosine, glycine and lysine, the positions occupied by tyrosine, which has been proved to be converted into dihydroxyphenylalanine, were well preserved. Pw-Vit20 and Pw-Vit36 were found to be monoexonic genes with variably diverged variants scattered into multiple genomic loci. Their protein products were localized in the vitelline follicles and eggshells. Expression of Pw-Vit20 was restricted to the egg and adult stages, thus suggesting a critical involvement of Pw-Vit20 in the parasite's fecundity activity. Conversely, Pw-Vit36 was constitutively expressed in the metacercariae and juvenile stages in the vitelline follicles and ducts, which suggested that the prepositioning of stem or primordial vitelline cells within the juveniles prior to sexual maturation. Pw-Vit36 might acquire a unique or additional function relevant to the maturation and/or development of the vitelline cells/follicles during the evolutionary period of P. westermani. Differential biological implications of multiple eggshell precursor proteins may provide insight into the molecular mechanism of eggshell formation and the developmental process of the vitelline follicles in the parasitic trematode.

Amino Acid Sequence↗
PubMed2005

Surveillance of different recombination defects in mouse spermatocytes yields distinct responses despite elimination at an identical developmental stage.

Fundamentally different recombination defects cause apoptosis of mouse spermatocytes at the same stage in development, stage IV of the seminiferous epithelium cycle, equivalent to mid-pachynema in normal males. To understand the cellular response(s) that triggers apoptosis, we examined markers of spermatocyte development in mice with different recombination defects. In Spo11(-)(/)(-) mutants, which lack the double-strand breaks (DSBs) that initiate recombination, spermatocytes express markers of early to mid-pachynema, forming chromatin domains that contain sex body-associated proteins but that rarely encompass the sex chromosomes. Dmc1(-)(/)(-) spermatocytes, impaired in DSB repair, appear to arrest at or about late zygonema. Epistasis analysis reveals that this earlier arrest is a response to unrepaired DSBs, and cytological analysis implicates the BRCT-containing checkpoint protein TOPBP1. Atm(-)(/)(-) spermatocytes show similarities to Dmc1(-)(/)(-) spermatocytes, suggesting that ATM promotes meiotic DSB repair. Msh5(-)(/)(-) mutants display a set of characteristics distinct from these other mutants. Thus, despite equivalent stages of spermatocyte elimination, different recombination-defective mutants manifest distinct responses, providing insight into surveillance mechanisms in male meiosis.

Animals↗
PubMed1983

The messenger RNA for alcohol dehydrogenase in Drosophila melanogaster differs in its 5' end in different developmental stages.

Alcohol dehydrogenase (EC 1.1.1.1) of Drosophila melanogaster is coded by a single structural gene, active in both larvae and adults. The major larval and adult transcripts of Adh differ in their 5'-untranslated regions. The major larval mRNA is about 1100 bases long, some 50 bases shorter than the major adult transcript. The 5' end of the larval mRNA is colinear with the genomic sequence immediately adjacent to the coding region, starting 70 base pairs (bp) upstream of the initiation codon. By contrast, the adult mRNA shares only 36 of its 123 5'-untranslated bases with the larval mRNA; the remaining 87 are encoded by a sequence 654 bp upstream. Both initiation sites are preceded by a TATA box some 24 bp upstream. The developmental specificity of Adh expression is seen, therefore, to have a counterpart in the specificity of transcription initiation at the two separate promoter regions.

Alcohol Dehydrogenase↗
PubMed1989

[Analysis of antigenic specificities of Paragonimus westermani developmental stages using immunoblot technique].

Serodiagnosis of parasitic infections is widely used, since parasites or their eggs are not always detected by ordinary methods. The sensitive tests such as ELISA are highly dependent on the purity of antigens used. To solve this problem, many workers have tried to find species-specific components of antigens. The present study was performed to determine the antigenic profile of crude saline extracts of 3, 5, 8 and 12-week old P. westermani worms, which were collected from experimentally infected cats, based on SDS-PAGE and immunoblot technique. The results were as follows: 1. The SDS-PAGE showed at least 30 protein bands ranging from 229 kDa to 10 kDa molecular weight. The protein components of P. westermani changed chronologically during its developmental period. The 229 kDa band was recognized only in 12-week old worms (SEP12). 2. Analysis by ELISA showed a significant increase in antibody levels at 3 weeks in infected cats using crude saline extract antigens (SEP3, SEP5, SEP8, SEP12). 3. By EITB using SEP3 and SEP5, infected cats recognized major protein bands with molecular weight of 60, 35, 28, 25 or 21 kDa at 3-12 weeks of infection, and 3 additional antigens, 19, 13 and 10 kDa, were detected at 8-12 weeks of infections. 4. Using SEP8, 5 antigens, 91, 85, 31, 25 and 21 kDa, were consistently detected by all infected sera tested. In addition, 3 antigens of 19, 13 and 10 kDa were detected at 8-12 weeks of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Developmental-stage-specific expression and regulation of an amphotropic retroviral receptor in hematopoietic cells.

Expression of the transmembrane receptor protein Ram-1 may be critical to optimizing retroviral gene transfer. Ram-1 acts as both a sodium-dependent phosphate transporter and a receptor for amphotropic retroviruses. We previously reported detectable Ram-1 in murine hematopoietic fetal liver cells (FLC) despite resistance of these cells to amphotropic retroviral transduction (infection). We document here that Ram-1 expression is completely absent in murine yolk sac cells from days 9.5 through 13.5 of ontogeny and first appears at low levels in midgestational FLC between days 13.5 and 14.5. In addition, Ram-1 expression is detected only in more differentiated populations within FLC, day 14.5, and not in those highly enriched for stem cells, indicating developmental regulation of Ram-1 during murine hematopoiesis. Others have reported the in vitro use of phosphate-free medium as a stimulus to increase levels of Ram-1 mRNA in nonhematopoietic cells. We now demonstrate that Ram-1 poly(A)+ mRNA increases significantly following culture of FLC in phosphate-free medium. Further, transduction of FLC in phosphate-free medium with an amphotropic retrovirus containing the multiple drug resistance gene leads to gene transfer not observed previously. These data demonstrate that (i) the normal resistance of FLC to amphotropic transduction is most likely due to an insufficient number of Ram-1 molecules for efficient retroviral recognition and binding, and (ii) Ram-1 can be upregulated by increasing the need for phosphate transport across the cell membrane.

Animals↗
PubMed2003

Expression pattern of Cubitus interruptus from the mulberry silkworm Bombyx mori in late developmental stages.

A partial genomic clone of Bombyx mori homologue of the segment polarity gene Cubitus interruptus ( BmCi), encoding the conserved zinc finger domain and harbouring two introns, has been characterized. BmCi was expressed in the silkglands of B. mori from embryonic to the late larval stages(3rd, 4th and 5th intermoults). The expression was confined to the anterior region of the middle silkglands, overlapping with the domain of sericin-2 expression and excluding the domains of Bm invected expression, namely the middle and posterior regions of the middle silkglands. In the wing discs, the expression was restricted to the anterior compartment, which increased from 4th to 5th larval intermoults and declined later in the pupal wing buds. In gonadal tissues (both ovaries and testes) BmCi was expressed from the larval to pupal stages. The transcripts were localized to the sperm tubes containing spermatogonia in the testis of Bombyx larvae. BmCi expression, however, was not detected in any of these tissues during the moulting stages. Expression of Ci in the wing discs and gonads is evolutionarily conserved, while the silkgland represents a novel domain. Our results imply that BmCi is involved in the specification and maintenance of micro-compartment identity within the middle silkglands.

Animals↗
PubMed1978

Observations on living rat spermatogenic cells in different developmental stages.

In the seminiferous tubules of the rat, as in most mammalian species, the developing germ cells form associations with constant cell composition. These cellular associations or stages follow each other in a regular manner along the seminiferous tubules giving rise to seminiferous epithelial wave. When a freshly isolated unstained seminiferous tubulus of the rat is subjected to transillumination under a stereomicroscope, the different segments of the seminiferous epithelial wave absorb light in a characteristic manner permitting their recognition. Using this technique, small segments with accurately known cell composition can be isolated and studied in living state with phase-contrast microscopy. In several cases, the phase-contrast microscopy gives more information about the cell morphology than conventional histological methods. In this study all major developmental steps from early spermatogonia to mature spermatids have been described. The findings of the present study can be used as reference material in the evaluation and identification of the various cell types of the seminiferous tubules obtained, e.g. by the Staput fractionation method. In addition, the findings may be helpful in the evaluation of spermatogenic and Sertoli cells in culture conditions.

Animals↗
PubMed1977

Characterization of a myelin-related fraction (SN 4) isolated from rat forebrain at two developmental stages.

A myelin-related fraction (SN 4) was isolated from forebrain of 17- and 40-day-old rats. Fraction SN 4 was obtained as a supernatant in a slow speed differential centrifugation of a myelin fraction. In contrast to multilamellar myelin fraction, SN 4 consisted of small vesicular profiles of a mixture of single membranes and some triple-layered structures. All typical myelin components were found in the SN 4 fraction from adult rat brain but their relative proportion was different from that of myelin: Wolfgram protein, myelin glycoproteins and 2',3'-cyclic nucleotide 3'-phosphohydrolase were increased, while basic proteins and proteolipid protein were decreased significantly. In contrast, the lipid composition appeared very similar to the one found in myelin. SN 4 from 17-day-old rat brains was essentially similar to that from adults, except that the major myelin glycoprotein was not enriched in comparison to myelin. Developmental changes found in myelin were also present in the SN 4 fraction. The specific radioactivity of the fucose-labeled major myelin glycoprotein was similar in SN 4 and in myelin. The particular composition of fraction SN 4 suggests that this material is not significantly contaminated by non-myelin-related membranes but rather supports the hypothesis that it could be enriched in a membrane representing a zone of transition during the formation of myelin and which is subjected to a remodelling of its protein components.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed2006

Cloning and nucleotide sequencing of three heat shock protein genes (hsp90, hsc70, and hsp19.5) from the diamondback moth, Plutella xylostella (L.) and their expression in relation to developmental stage and temperature.

Heat shock protein genes, hsp90, hsc70, and hsp19.5, were cloned and sequenced from the diamondback moth, Plutella xylostella (L.) by RT-PCR and RACE method. The cDNA sequence analysis of hsp90 and hsp19.5 revealed open reading frames (ORFs) of 2,151 and 522 bp in length, which encode proteins with calculated molecular weights of 82.4 and 19.5 kDa, respectively. Analysis of cDNA from hsc70 revealed an ORF of 1,878 bp coding a protein with a calculated molecular weight of 69.3 kDa. Furthermore, the analysis of genomic DNA from hsc70 confirmed the presence of introns while no introns were apparent in hsp90 and hsp19.5. Southern blot analysis suggested the presence of multiple copies of each gene family in the DBM genome. Detectable expression of hsp19.5 was observed at the pupal stage while expression of hsp90 and hsc70 was detected at both pupal and adult stages. At adult stage, females showed a higher expression of hsp90 and hsc70 than males. An increased expression was observed in all three genes after exposure to a high temperature in both sexes. These results suggest that in addition to a heat shock response, these HSP genes might be involved in other functions during the course of development in DBM.

Amino Acid Sequence↗