Uridineinbau in die Nucleinsäuren von Furchungsstadien der Eier des Seeigels Paracentrotus Lividus

1967 ◽  
Vol 22 (11) ◽  
pp. 1176-1182 ◽  
Author(s):  
G. Czihak ◽  
H. G. Wittmann ◽  
I. Hindennach
Keyword(s):  
Sea Urchin ◽  
Rna Synthesis ◽  
Fission Products ◽  
Paracentrotus Lividus ◽  
The Other ◽  
Soluble Form ◽  
Blastula Stage ◽  
High Turnover ◽  
Cell Stage ◽  
Sea Urchin Egg

1. Uridine taken up during the 16th-cell stage of the sea urchin egg is stored in acid soluble form.2. During the interphase of this stage uridine is used for an RNA-synthesis in the micromeres, the smallest blastomeres of the egg, which have a prolonged interphase. There seems to occur no RNA-synthesis in the other blastomeres of this stage or the synthesis in these cells is considerably smaller. The RNA of the micromeres has a high turnover, it is neither tRNA nor rRNA but probably mRNA.3. 2½ hours after the 16th-cell stage — this is in the young blastula stage — about 5½ hours after fertilization, at least half of the micromere-RNA is already decomposed, the fission products of which having been used together with the stored uridine to synthesize rRNA and (after methylation of the uridine) DNA.

Enucleation of Sea-Urchin Blastomeres with or without Removal of Asters

1952 ◽  
Vol s3-93 (24) ◽  
pp. 475-486
Author(s):  
I. JOAN LORCH
Keyword(s):  
Sea Urchin ◽  
Nuclear Membrane ◽  
Cell Stage ◽  
Sea Urchin Egg ◽  
In Cells

The following experiments were carried out on one blastomere at the two-cell stage of the sea-urchin egg: 1. Removal of the nucleus. 2. Removal of the nucleus and surrounding cytoplasm (centrosphere). 3. Attempted removal of the centrosphere only. In cells from which the nucleus had been removed the asters multiplied for up to 7 hours and then disappeared. During the period of aster multiplication, cleavage furrows often appeared between the asters but did not succeed in dividing the cell. After about 8 hours, cleavage into a large number of spheroidal cells occurred. When the nucleus and centrosphere were removed no asters were formed and no cleavage furrows were observed until after about 8 hours, when division into a large number of spheroidal cells occurred. When attempts were made to remove the centrosphere, leaving the nucleus intact, asters were always eventually re-formed Before the re-formation of asters neither the nucleus nor the cytoplasm divided although dissolution of the nuclear membrane, followed by its reappearance, occurred. After re-formation of the asters cleavage appeared to be normal.

Incorporation of Uridine in Cleavage Stage Eggs of the Sea Urchin Paracentrotus Lividus

1971 ◽  
Vol 26 (8) ◽  
pp. 816-821 ◽  
Author(s):  
Larry E. Bockstahler
Keyword(s):  
Ion Exchange ◽  
Sea Urchin ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Paracentrotus Lividus ◽  
Cleavage Stage ◽  
Early Cleavage ◽  
Cell Stage ◽  
Cleavage Stages ◽  
Layer Chromatography

Incorporation of uridine in cleavage stage eggs of the sea urchin Paracentrotus lividus was investigated. It was shown by ion exchange and thin layer chromatography that most of the uridine taken up during the 16-cell stage was converted into UTP with some incorporation into UDP and UMP. Conversion of uridine to these phosphorylated nucleosides occurred throughout early cleavage stages. A very small amount of uridine taken up by cleavage stage eggs is incorporated into RNA heterogeneous in size. This RNA was examined by polyacrylamide gel electrophoresis.

Origin and behaviour of pigment cells in sea urchin embryos

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S42-S43 ◽  
Author(s):  
Tetsuya Kominami
Keyword(s):  
Sea Urchin ◽  
Pigment Cell ◽  
Cell Lineage ◽  
Pigment Cells ◽  
Cleavage Stage ◽  
Fate Map ◽  
Blastula Stage ◽  
Cell Stage ◽  
Stage Embryo ◽  
Founder Cells

Sea urchin pluteus larvae contain dozens of pigment cells in their ectoderm. These pigment cells are the descendants of the veg2 blastomeres of the 60-cell stage embryo. According to the fate map made by Ruffins and Ettensohn, the prospective pigment cells occupy the central region of the vegetal plate. Most of these prospective pigment cells exclusively give rise to pigment cells. Therefore, specification of the pigment cell lineage should occur at some point between the 60-cell and mesenchyme blastula stage. However, the detailed process of the specification of the pigment lineage is unknown.When are pigment cells specified? Are cell interactions necessary for the specification? Do founder cells exist? To answer these questions, I treated embryos with Ca2+-free seawater during the cleavage stage and examined the number of pigment cells observed in pluteus larvae. Treatment at 5.5–8.5 h and especially 7.5–10.5 h postfertilisation markedly reduced the number of pigment cells. The decrease was statistically significant. On the other hand, the treatment at 3.5–6.5 h or 9.5–12.5 h never reduced the number of pigment cells. By examining the frequency of the appearance of embryos whose numbers of pigment cells were less than 20, it was also found that the numbers of pigment cells were frequently in multiples of 4. Embryos having 4, 8, 12, 16 and 20 pigment cells were more frequently observed. Statistics indicated that the frequency of appearance was not random. These results indicated that cell contacts are necessary for the specification of pigment cells and that the specification occurs from 7 to 10 h postfertilisation. The results also suggest that the founder cells, if they exist, divide twice before they differentiate into pigment cells.

scholarly journals Effect of non-histone chromosomal proteins on transcription in vitro in sea-urchin

1978 ◽  
Vol 174 (1) ◽  
pp. 95-102 ◽  
Author(s):  
E Di Mauro ◽  
F Pedone ◽  
M Pomponi
Keyword(s):  
Sea Urchin ◽  
Rna Synthesis ◽  
Paracentrotus Lividus ◽  
Chromosomal Proteins ◽  
Stage Of Development ◽  
Transcription Process ◽  
Initiation Step ◽  
Transcription In Vitro ◽  
Transcription 3

Non-histone chromosomal proteins prepared from chromosomal material of the sea-urchin Paracentrotus lividus affect RNA synthesis in vitro. 1. The extent of transcription can be radically changed from inhibition to stimulation, depending on the DNA/non-histone chromosomal proteins ratio. 2. A correlation exists between stage of development and influence on transcription. 3. Non-histone chromosomal proteins exert their action by intervening directly on some initiation step of RNA synthesis, as shown by the numbers of initiation events that take place in their presence or absence. 4. Stimulatory activity is observed only in restrictive conditions of ionic strength and temperature. These observations are in agreement with models that predict for non-histone chromosomal proteins a regulatory role on the transcription process exerted through a modulation of promoter availability.

scholarly journals STUDIES ON SULFHYDRYL GROUPS DURING CELL DIVISION OF SEA URCHIN EGG

1960 ◽  
Vol 8 (3) ◽  
pp. 603-607 ◽  
Author(s):  
Hikoichi Sakai
Keyword(s):  
Cell Division ◽  
Sea Urchin ◽  
Sulfhydryl Groups ◽  
Cell Stage ◽  
Sea Urchin Eggs ◽  
Maximum Value ◽  
Sea Urchin Egg ◽  
Egg Cortex

Masses of cortices of both unfertilized and fertilized sea urchin eggs can be isolated by crushing eggs in hypotonic MaCl2 (0.1 M) solution. The amount of cortical material in terms of protein-N increases steadily after fertilization until the monaster stage and thereafter remains almost constant until well into the two-cell stage. The amount of bound—SH per protein-N of the egg cortex also increases after fertilization, reaches a maximum value at the amphiaster stage and thereafter decreases rapidly as the cleavage of the cell proceeds.

scholarly journals Changes in responsiveness of preimplantation mouse embryos to serum

Development ◽  
1978 ◽  
Vol 45 (1) ◽  
pp. 295-301
Author(s):  
Simon B. Fishel ◽  
M. Azim H. Surani
Keyword(s):  
Bovine Serum ◽  
Rna Synthesis ◽  
Blastocyst Stage ◽  
Mouse Embryos ◽  
The Other ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Serum Albumen

Changes in uptake of radioactive uridine and its incorporation into RNA were determined in preimplantation mouse embryos, from the 2-cell to the blastocyst stage, as a measure of their responsiveness to extracellular conditions. Two media were tested, one contained serum and the other contained bovine serum albumen as a control. An increase in the acid-soluble pool occurred at the 8-cell stage and a marked increase in RNA synthesis occurred at the early blastocyst stage when the embryos were incubated with serum.

Spatial and temporal expression pattern during sea urchin embryogenesis of a gene coding for a protease homologous to the human protein BMP-1 and to the product of the Drosophila dorsal-ventral patterning gene tolloid

Development ◽  
1992 ◽  
Vol 114 (1) ◽  
pp. 147-163 ◽  
Author(s):  
T. Lepage ◽  
C. Ghiglione ◽  
C. Gache
Keyword(s):  
Sea Urchin ◽  
Catalytic Domain ◽  
Intracellular Localization ◽  
Regulation Of Gene Expression ◽  
Drosophila Embryo ◽  
Limited Area ◽  
Fate Map ◽  
Blastula Stage ◽  
Cell Stage ◽  
Short Period

A cDNA clone coding for a sea urchin embryonic protein was isolated from a prehatching blastula lambda gt11 library. The predicted translation product is a secreted 64 × 10(3) Mr enzyme designated as BP10. The protein contains several domains: a signal peptide, a putative propeptide, a catalytic domain with an active center typical of a Zn(2+)-metalloprotease, an EGF-like domain and two internal repeats similar to repeated domains found in the C1s and C1r serine proteases of the complement cascade. The BP10 protease is constructed with the same domains as the human bone morphogenetic protein BMP-1, a protease described as a factor involved in bone formation, and as the recently characterized product of the tolloid gene which is required for correct dorsal-ventral patterning of the Drosophila embryo. The transcription of the BP10 gene is transiently activated around the 16- to 32-cell stage and the accumulation of BP10 transcripts is limited to a short period at the blastula stage. By in situ hybridization with digoxygenin-labelled RNA probes, the BP10 transcripts were only detected in a limited area of the blastula, showing that the transcription of the BP10 gene is also spatially controlled. Antibodies directed against a fusion protein were used to detect the BP10 protein in embryonic extracts. The protein is first detected in early blastula stages, its level peaks in late cleavage, declines abruptly before ingression of primary mesenchyme cells and remains constant in late development. The distribution of the BP10 protein during its synthesis and secretion was analysed by immunostaining blastula-stage embryos. The intracellular localization of the BP10 staining varies with time. The protein is first detected in a perinuclear region, then in an apical and submembranous position just before its secretion into the perivitelline space. The protein is synthesized in a sharply delimited continuous territory spanning about 70% of the blastula. Comparison of the size and orientation of the labelled territory in the late blastula with the fate map of the blastula stage embryo shows that the domain in which the BP10 gene is expressed corresponds to the presumptive ectoderm. Developing embryos treated with purified antibodies against the BP10 protein and with synthetic peptides derived from the EGF-like domain displayed perturbations in morphogenesis and were radialized to various degrees. These results are consistent with a role for BP10 in the differentiation of ectodermal lineages and subsequent patterning of the embryo. On the basis of these results, we speculate that the role of BP10 in the sea urchin embryo might be similar to that of tolloid in Drosophila. We discuss the idea that the processes of spatial regulation of gene expression along the animal-vegetal in sea urchin and dorsal-ventral axes in Drosophila might have some similarities and might use common elements.

Functional visualization of the separate but interacting calcium stores sensitive to NAADP and cyclic ADP-ribose

2000 ◽  
Vol 113 (24) ◽  
pp. 4413-4420 ◽  
Author(s):  
H.C. Lee ◽  
R. Aarhus
Keyword(s):  
Endoplasmic Reticulum ◽  
Sea Urchin ◽  
The Other ◽  
Calcium Stores ◽  
Cellular Functions ◽  
Large Size ◽  
Opposite Pole ◽  
Visual Evidence ◽  
Sea Urchin Egg ◽  
Cyclic Adp Ribose

Cells possess multiple Ca(2+) stores and their selective mobilization provides the spatial-temporal Ca(2+) signals crucial in regulating diverse cellular functions. Except for the inositol trisphosphate (IP(3))-sensitive Ca(2+) stores, the identities and the mechanisms of how these internal stores are mobilized are largely unknown. In this study, we describe two Ca(2+) stores, one of which is regulated by cyclic ADP-ribose (cADPR) and the other by nicotinic acid adenine dinucleotide phosphate (NAADP). We took advantage of the large size of the sea urchin egg and stratified its organelles by centrifugation. Using photolysis to produce either uniform or localized increases of cADPR and NAADP from their respective caged analogs, the two separate stores could be visually identified by Ca(2+) imaging and shown to be segregated to the opposite poles of the eggs. The cADPR-pole also contained the IP(3)-sensitive Ca(2+) stores, the egg nucleus and the endoplasmic reticulum (ER); the latter was visualized using Bodipy-thapsigargin. On the other hand, the mitochondria, as visualized by rhodamine 123, were segregated to the opposite pole together with the NAADP-sensitive calcium stores. Fertilization of the stratified eggs elicited a Ca(2+) wave starting at the cADPR-pole and propagating toward the NAADP-pole. These results provide the first direct and visual evidence that the NAADP-sensitive Ca(2+) stores are novel and distinct from the ER. During fertilization, communicating signals appear to be transmitted from the ER to NAADP-sensitive Ca(2+) stores, leading to their activation.

scholarly journals Studies on Sulfhydryl Groups during Cell Division of Sea Urchin Egg

1962 ◽  
Vol 45 (3) ◽  
pp. 427-438 ◽  
Author(s):  
Hikoichi Sakai
Keyword(s):  
Cell Division ◽  
Sea Urchin ◽  
Soluble Fraction ◽  
Water Soluble ◽  
The Other ◽  
Original Sample ◽  
Water Soluble Fraction ◽  
Sea Urchin Egg ◽  
Soluble Fractions

The contractility of the thread model prepared from the KCl-soluble proteins of the egg and in vivo factors for the contraction are investigated in Hemicentrotus, Anthocidaris, and Pseudocentrotus eggs. The contractility of the thread model induced by metal ions or cystine changes during development in the characteristic pattern of high at the metaphase and low at the monaster and the interkinetic stages. The change in contractility is paralleled by the change in the —SH content of the protein. The water-soluble fraction of the eggs has activity in causing contraction of the thread model. This activity changes during development in the same way as the contractility itself. The contraction of the thread induced by the water-soluble fractions is accompanied by a decrease in the —SH content of the thread. The activity of the water-soluble fraction in inducing the contraction is proportional to its ability to decrease the number of —SH groups. On boiling, the activity is largely destroyed. The activity is due to two components, one being non-dialyzable and the other dialyzable. Separately each component has little effect, but when mixed, the activity of the original sample is completely restored.

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