The second polar lobe of theSabellaria cementarium embryo plays an inhibitory role in apical tuft formation

1983 ◽  
Vol 192 (3-4) ◽  
pp. 120-129 ◽  
Author(s):  
Jo Ann Render
Keyword(s):  
Polar Lobe ◽  
Apical Tuft ◽  
Inhibitory Role

The effect of removing the polar lobe in centrifuged eggs of Dentalium

Development ◽  
1968 ◽  
Vol 19 (1) ◽  
pp. 33-42
Author(s):  
N. H. Verdonk
Keyword(s):  
Normal Distribution ◽  
Polar Lobe ◽  
Morphogenetic Substances ◽  
Apical Tuft ◽  
Trochophore Larva

Classical evidence for the existence of morphogenetic substances was provided by experiments with spiralian eggs possessing a polar lobe: Ilyanassa (Crampton, 1896; Clement, 1952, 1956, 1962); Dentalium (Wilson, 1904); Chaetopterus (Tyler, 1930); Sabellaria (Hatt, 1932; Novikoff, 1938); and Mytilus (Rattenbury & Berg, 1954). Eggs from which the polar lobe had been removed developed into embryos with specific abnormalities. In Dentalium, after removal of the polar lobe at the trefoil stage, a trochophore larva is formed without post-trochal region and apical tuft. Removal of the polar lobe at second cleavage causes a larva without post-trochal region, but with an apical tuft. Wilson concluded that specific cytoplasmic materials essential to the formation of the apical tuft are contained in the first but no longer in the second polar lobe. Centrifuging the uncleaved egg just before first cleavage will disturb the normal distribution of substances.

Experimental studies on morphogenetic factors localized in the first and the second polar lobe of Dentalium eggs

Development ◽  
1970 ◽  
Vol 23 (1) ◽  
pp. 237-243
Author(s):  
W. L. M. Geilenkirchen ◽  
N. H. Verdonk ◽  
L. P. M. Timmermans
Keyword(s):  
Mytilus Edulis ◽  
Experimental Studies ◽  
Ilyanassa Obsoleta ◽  
Polar Lobe ◽  
Apical Tuft ◽  
The Third ◽  
Vegetal Pole ◽  
Morphogenetic Factors

During the development of several annelids and molluscs, a lobe of protoplasm is observed to protrude from the vegetal pole of the egg during the first cleavages. Removal of this polar lobe causes characteristic defects in the developing larvae as has been observed in the scaphopod, Dentalium (Wilson, 1904; Verdonk, 1968), the annelid Sabellaria (Hatt, 1932; Novikoff, 1938), the gastropod Ilyanassa obsoleta (Crampton, 1896; Clement, 1952) and the lamellibranch, Mytilus edulis (Rattenbury & Berg, 1954). In Dentalium a polar lobe is formed at the first, the second and the third cleavage. The lobes contain part of the cytoplasm, which later is confined to the D blastomere. After removal of the first polar lobe, embryos develop in which the post-trochal region and the apical tuft are absent. After removal of the second polar lobe the post-trochal region of the embryos is greatly reduced, but they develop an apical tuft (Wilson, 1904).

The localization of morphogenetic factors in uncleaved eggs of Dentalium

Development ◽  
1971 ◽  
Vol 25 (1) ◽  
pp. 57-63
Author(s):  
N. H. Verdonk ◽  
W. L. M. Geilenkirchen ◽  
L. P. M. Timmermans
Keyword(s):  
Polar Lobe ◽  
Apical Tuft ◽  
Morphogenetic Factors

The effect of removing parts of unfertilized and fertilized eggs of Dentalium has been studied. Up to 70 % of the volume of a 1st polar lobe can be removed from the vegetal side of both unfertilized and fertilized eggs, without influencing apical tuft formation. The post-trochal region is reduced. These eggs form a reduced polar lobe at first cleavage. After removal of more than 70 % of the volume of a 1st polar lobe from the vegetal side of an uncleaved egg, before or after fertilization, no polar lobe is formed and larvae develop without apical tuft or post-trochal region. The polar lobe area is quantitatively determined in the uncleaved egg, but after fertilization of isolated vegetal fragments regulation occurs and the polar lobe becomes proportional in size to the fragment. Feulgen-positive granules, present at the vegetal side of the uncleaved egg, can be removed without influencing apical tuft formation. They may be important as determinants for the formation of the post-trochal region or adult structures.

Local accumulation of Feulgen-positive granules in the egg cortex of Dentalium dentale L.

Development ◽  
1970 ◽  
Vol 23 (1) ◽  
pp. 245-252
Author(s):  
Lucy P. M. Timmermans ◽  
W. L. M. Geilenkirchen ◽  
N. H. Verdonk
Keyword(s):  
Polar Lobe ◽  
Apical Tuft ◽  
The Third ◽  
The One ◽  
Local Accumulation ◽  
Egg Cortex

A special feature of eggs of several species of annelids and molluscs is the formation of a polar lobe at stage-specific intervals during the cleavage phase. In the scaphopod Dentalium, a polar lobe develops at the first, the second and the third cleavage (Wilson, 1904). The cytoplasm set apart in the polar lobes is ultimately confined to the D blastomere and its derivative cells. Wilson observed that after removal of the polar lobe at the first cleavage a larva develops which lacks an apical tuft and the post-trochal region. After removal of the polar lobe at the second cleavage a larva develops which lacks most of the post-trochal region but possesses an apical tuft. A similar result to the one following the removal of the first polar lobe is obtained by removal of the vegetal one-third of an unfertilized egg.

Inhibitory Role of Plasminogen Activator Inhibitor-1 in Arterial Wound Healing and Neointima Formation

Circulation ◽  
1997 ◽  
Vol 96 (9) ◽  
pp. 3180-3191 ◽  
Author(s):  
Peter Carmeliet ◽  
Lieve Moons ◽  
Roger Lijnen ◽  
Stefaan Janssens ◽  
Florea Lupu ◽  
...  
Keyword(s):  
Wound Healing ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Neointima Formation ◽  
Plasminogen Activator Inhibitor 1 ◽  
Inhibitory Role ◽  
Activator Inhibitor

scholarly journals The inhibitory role of synthesized Nickel oxide nanoparticles against Hep-G2, MCF-7, and HT-29 cell lines: the inhibitory role of NiO NPs against Hep-G2, MCF-7, and HT-29 cell lines

2021 ◽  
Vol 14 (3) ◽  
pp. 443-453
Author(s):  
Mohammad Amin Jadidi Kouhbanani ◽  
Yasin Sadeghipour ◽  
Mina Sarani ◽  
Erfan Sefidgar ◽  
Saba Ilkhani ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Cell Lines ◽  
Oxide Nanoparticles ◽  
Hep G2 ◽  
Nickel Oxide Nanoparticles ◽  
Inhibitory Role ◽  
Nio Nps ◽  
Ht 29 ◽  
Mcf 7

scholarly journals Correction to: Inactivation of the Wnt/β-catenin signaling pathway underlies inhibitory role of microRNA-129-5p in epithelial–mesenchymal transition and angiogenesis of prostate cancer by targeting ZIC2

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhenming Jiang ◽  
Yuxi Zhang ◽  
Xi Chen ◽  
Pingeng Wu ◽  
Dong Chen
Keyword(s):  
Prostate Cancer ◽  
Signaling Pathway ◽  
Epithelial Mesenchymal Transition ◽  
Mesenchymal Transition ◽  
Inhibitory Role

An amendment to this paper has been published and can be accessed via the original article.

The inhibitory role of clioquinol in the fibrillation of hen egg white lysozyme

2021 ◽  
pp. 138830
Author(s):  
Baoliang Ma ◽  
Haohao Wang ◽  
Yujie Liu ◽  
Fang Wu ◽  
Xudong Zhu
Keyword(s):  
Egg White ◽  
Hen Egg White Lysozyme ◽  
Egg White Lysozyme ◽  
Inhibitory Role ◽  
Hen Egg White ◽  
Hen Egg

scholarly journals Entry-inhibitory role of catechins against SARS-CoV-2 and its UK variant

2021 ◽  
pp. 104560
Author(s):  
Susmit Mhatre ◽  
Nitisha Gurav ◽  
Mansi Shah ◽  
Vandana Patravale
Keyword(s):  
Inhibitory Role
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