Analysis of a Cytoplasmic Determinant in an Insect Egg

1977 ◽  
pp. 5-21
Author(s):  
KLAUS KALTHOFF
Keyword(s):  
Insect Egg ◽  
Cytoplasmic Determinant

Insectivorous Birds Are Attracted by Plant Traits Induced by Insect Egg Deposition

2018 ◽  
Vol 44 (12) ◽  
pp. 1127-1138 ◽  
Author(s):  
Elina Mäntylä ◽  
Sven Kleier ◽  
Carita Lindstedt ◽  
Silke Kipper ◽  
Monika Hilker
Keyword(s):  
Plant Traits ◽  
Insectivorous Birds ◽  
Insect Egg ◽  
Egg Deposition

scholarly journals The Structure of the Insect Egg-Shell in Relation to the Respiration of the Embryo

1950 ◽  
Vol 26 (4) ◽  
pp. 327-334
Author(s):  
P. H. TUFT
Keyword(s):  
Rhodnius Prolixus ◽  
Gaseous Exchange ◽  
Insect Egg ◽  
Physical Conditions ◽  
Egg Shell ◽  
Gas Space ◽  
The Relationship ◽  
Sufficient Oxygen

1. The site of gaseous exchange in the eggs of Rhodnius prolixus (Stahl) is shown to be the rim of the cap which covers the anterior end of the egg. Most of the oxygen consumed by the embryo enters the egg through the micropyles and pseudomicropyles which penetrate the shell in this region. 2. The physical conditions necessary for the passage of sufficient oxygen through these pores is discussed. A continuous gas space under the shell--the presence of which can be deduced on theoretical grounds--is shown to exist in the Rhodnius egg. 3. The relationship between waterproofing and the permeability of the shell to oxygen is discussed.

Insect egg sets on angiosperm leaves from the Lower Cretaceous of Negev, Israel

2007 ◽  
Vol 28 (5) ◽  
pp. 803-811 ◽  
Author(s):  
Valentin Krassilov ◽  
Natalia Silantieva ◽  
Meinolf Hellmund ◽  
Winfried Hellmund
Keyword(s):  
Lower Cretaceous ◽  
Insect Egg

A cytoplasmic determinant for dorsal axis formation in an early embryo of Xenopus laevis

Development ◽  
1990 ◽  
Vol 110 (4) ◽  
pp. 1051-1056 ◽  
Author(s):  
M. Yuge ◽  
Y. Kobayakawa ◽  
M. Fujisue ◽  
K. Yamana
Keyword(s):  
Xenopus Laevis ◽  
Direct Evidence ◽  
Early Embryo ◽  
Dorsal Side ◽  
Axis Formation ◽  
Secondary Axis ◽  
Dorsal Axis ◽  
Cell Embryo ◽  
Dorsal Cells ◽  
Cytoplasmic Determinant

In Xenopus laevis, dorsal cells that arise at the future dorsal side of an early cleaving embryo have already acquired the ability to cause axis formation. Since the distribution of cytoplasmic components is markedly heterogeneous in an egg and embryo, it has been supposed that the dorsal cells are endowed with the activity to form axial structures by inheriting a unique cytoplasmic component or components localized in the dorsal region of an egg or embryo. However, there has been no direct evidence for this. To examine the activity of the cytoplasm of dorsal cells, we injected cytoplasm (dorsal cytoplasm) from dorsal vegetal cells of a Xenopus 16-cell embryo into ventral vegetal cells of a simultaneous recipient. The cytoplasm caused secondary axis formation in 42% of recipients. Histological examination revealed that well-developed secondary axes included notochord, as well as a neural tube and somites. However, injection of cytoplasm of ventral vegetal cells never caused secondary axis and most recipients became normal tailbud embryos. Furthermore, about two-thirds of ventral isolated halves injected with dorsal cytoplasm formed axial structures. These results show that dorsal, but not ventral, cytoplasm contains the component or components responsible for axis formation. This can be the first step towards identifying the molecular basis of dorsal axis formation.

Establishment of Polarity in the Insect Egg

1985 ◽  
pp. 347-377 ◽  
Author(s):  
HERWIG O. GUTZEIT ◽  
KLAUS SANDER
Keyword(s):  
Insect Egg

scholarly journals Insect egg size and shape evolve with ecology but not developmental rate

Nature ◽  
2019 ◽  
Vol 571 (7763) ◽  
pp. 58-62 ◽  
Author(s):  
Samuel H. Church ◽  
Seth Donoughe ◽  
Bruno A. S. de Medeiros ◽  
Cassandra G. Extavour
Keyword(s):  
Egg Size ◽  
Developmental Rate ◽  
Insect Egg ◽  
Size And Shape

The Penetration of the Insect Egg-shells. I.—Penetration of the Chorion of Rhodnius prolixus, Stål

1948 ◽  
Vol 39 (3) ◽  
pp. 359-383 ◽  
Author(s):  
J. W. L. Beament
Keyword(s):  
Formic Acid ◽  
Aqueous Solutions ◽  
Random Distribution ◽  
Protein Layer ◽  
Insect Egg ◽  
Wetting Power ◽  
Egg Shells ◽  
Pass Through ◽  
Almost All ◽  
Considerable Period

The unspecialised portion of the shell and the cap of Rhodnius eggs are impermeable to almost all hydrophilic and lipophilic liquids. If water and very small ions pass through the chorion they must traverse a wax layer on the inside of the shell. Certain corrosive materials, e.g., glacial formic acid, may pass through the shell slowly.These conclusions, based on experiments with pieces of shell, have been confirmed in ovicidal experiments. A range of materials with widely differing properties enter the embryo only through the micropyles, of which there are approximately fifteen in the rim of each shell. At least one micropyle must be traversed to kill an egg but many eggs were killed when only one had been penetrated.A cement, applied by the female at oviposition, may occlude the outer orifice of a micropyle. The properties of the cement are described; it appears to be a tanned protein. Cement deposits are much more copious on the eggs laid by younger females. Such eggs are more resistant to ovicides because penetration is delayed. This increased resistance is more pronounced when oleophilic liquids are used owing to the rapidity with which they kill eggs from older females. The random distribution of cement is one cause of the variability of replicates in ovicidal tests.A detailed investigation has been made of factors governing liquids traversing the micropyles. Hydrophilic liquids invade the outer lipophilic part of the micropyle slowly; the displacement of air is the most important factor and small changes in the wetting power of the liquid make little difference to the rate of entry.Aqueous liquids aie absorbed into the protein lining of the inner portion of the micropyle. They reach the wax layer on the inside of the shell by migrating into and through the inner protein layer. The area which is invaded increases linearly with time. Mortality, therefore, increases as the square of the time of immersion, but it is proportional to the increase in concentration of a solute if the period of immersion is constant.Oleophilic liquids wet the micropyle actively. They may by-pass air and flow rapidly to the wax at the inner end of the tube. Wax solvents kill very quickly and are much more toxic than other lipophiles.Water in the micropyle and shell may affect the entrance of either type of liquid. In general it increases the toxicity of aqueous solutions and retards the entry of oils.Wax-emulsifying materials added to aqueous solutions do not produce great increases in toxicity. They are “filtered out” at the protein lining of the micropyle and do not reach the wax layer for a considerable period of time.

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