Further Notes on the Hardening of the Chorion of Salmon Eggs

Kusa, Mamoru

doi:10.1508/cytologia.15.145

Cited by 14 publications

(4 citation statements)

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“…A species comparison also suggests that eggs with thicker jelly coats -such as the demersal eggs of Atlantic and Pacific herringwill bind the maximum amount of cadmium during incubation in lower salinities. Nakano (1959) found that "hardening" of the fertilized egg, a process requiring calcium (Kusa, 1949) is inhibited by cadmium; Zotin (1958) showed that hardening of the egg involves a change in properties of the capsule. A question remains as to whether cadmium influences the properties of the capsule, the jelly coat, or both.…”

Section: Influencementioning

confidence: 99%

Osmotic responses of eggs and larvae of the Pacific herring to salinity and cadmium

Alderdice

Rao

Rosenthal

1979

Helgolander Wiss. Meeresunters

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. Yolk osmolalities decreased, after hatching of the larvae, to approximate those levels attained between 100 and 250 hr. An hypothesis is presented whereby minimum osmotic work is defined on the basis of isosmotic relations existing between yolk, perivitelline fluid, and incubation medium. This leads to the description of a range of salinities defined in terms of osmoregulatory scope. At the 5 ~ test temperature, incubation salinities associated with maximum osmoregulatory scope (13.2-19 %o) correspond closely to the range of salinities providing maximum or near-maximum hatches of viable larvae. The presence of a salinity-temperature interaction and its influence on the association between osmoregulatory scope and production of viable larvae is suggested as a mechanism underlying and providing the recognized plasticity of Pacific herring egg development. In a companion study involving cadmium as a contaminant, eggs !ncubated at 20 %~ S were exposed to 0, 1 or 10 ppm Cd in 5, 20 or 35 0/00 S for 48-hr periods at six stages of development between fertilization and hatching. Cd exposure resulted in a reduction in osmolality of perivitelline fluid. Reduction was greater in higher Cd concentrations and in eggs transferred to higher salinities. An hypothesis is presented to explain observed effects of Cd exposure on some physical properties of teleost eggs, including reductions in perivitelline fluid osmolality and egg volume. Finally, newly hatched (0-, 3-, 6-and 9-day old) larvae from eggs incubated at 20 %~ S (8.5 ~ were exposed to salinities from 0 to 50 %o for a period of 72 hr. Median tolerance limits (72-hr) were 2.8-5.2 %o for low salinities and 33-35.8 ~174 for high salinities. No trends in salinity tolerance were noted amongst the four ages of larvae. The data suggest that natural larvae entrained in sea water would be susceptible to salinity-induced mortality in salinities greater than about 20 %o. However, this conclusion is subject to confirmation in view of the low/low-high/high salinity-temperature interaction previously noted in relation to egg development, and its possible continuing influence in larval stages.

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Section: Influencementioning

confidence: 99%

Osmotic responses of eggs and larvae of the Pacific herring to salinity and cadmium

Alderdice

Rao

Rosenthal

1979

Helgolander Wiss. Meeresunters

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“…In fish eggs, some reactions or factors such as oxidation of sulfhydryl groups in chorion proteins (20, 21 ), 'hardening enzyme' (35), cortical alveolar substance and mucopolysaccharides (1 9), and some environmental factors such as pH and temperature (8) and/or Ca2+ (13,14,20) are reported to be related with hardening of the egg envelope (chorion).…”

Section: Discussionmentioning

confidence: 99%

Analysis of Hardening of the Egg Envelope (Chorion) of the Fish, Oryzias latipes

1991

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Hardening of the chorion of medaka eggs was quantitated in terms of the solubility of its constituent proteins. After activation of unfertilized eggs with the Ca*+-ionophore A231 87, hardening of chorion (named 'ionophore-activation hardening') proceeded and 60 min after activation the solubility of the proteins in 1 N NaOH had decreased to 20% of that of proteins of unhardened chorions. On SDS-PAGE, the chorions of unfertilized eggs gave four major protein bands (150, 83, 78 and 51 K). After Ca2+-ionophore activation, new two protein bands (135 and 61 K) appeared, with concurrent disappearance of all the original bands except the 51 K band. Isolated chorions of unfertilized eggs were also hardened by Ca2+ and 60 min after addition of Ca2+ the solubility of their proteins in 1 N NaOH had decreased to about 45% of that originally. During this type of hardening (named 'Ca2+-hardening'), however, the SDS-PAGE pattern of the proteins remained unchanged. Therefore, there are two mechanisms of hardening. The 'ionophore-activation hardening' was inhibited by cadaverine. When chorions were isolated 20 min after Ca2+-ionophore activation and kept in Ca'+-free conditions, the 'ionophore-activation hardening' process was arrested: further hardening was resumed on addition of Ca2+ to the medium. These results suggest the presence of some hardening machinery in isolated chorions.

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“…It is well known that chorion hardening is Ca'+-dependent (9, 13,16,26). If the homogenates of the unfertilized egg chorions were incubated with 0.1 M EDTA, their constituent proteins…”

Section: Hardening Of Chorion Isolated From Unfertilizedmentioning

confidence: 99%

Change in Component Proteins of the Egg Envelope (Chorion) of Rainbow Trout during Hardening

1991

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Egg envelope (chorion) of unfertilized eggs of rainbow trout, Oncorhynchus mykiss, consists of 4 major protein components whose molecular weights are approximately 110 K, 64 K, 56 K and 50 K. On hardening of the chorion after activation, 64 K, 56 K and 50 K components disappeared, some components higher than 160 K were newly formed and the solubility of the chorion in 1 N NaOH or 12 M urea-2% SDS-1% 2-mercaptoethanol (Sample Buffer) decreased. This implies that probable formation of covalent crosslinks between the constituents occurs during the hardening.Hardening occurred also in the chorion isolated from the unfertilized eggs. The conversion of the 64 K, 56 K and 50 K components into the higher molecular weight intermediates was CaZf-dependent, accelerated by 2-mercaptoethanol and inhibited by a high temperature (60°C). Optimum pH of this hardening system was acidic, i.e., 5.0 to 6.0.Cadaverine inhibited the change in solubility of chorion in NaOH or Sample Buffer, while it could not inhibit the disappearance of the 64 K, 56 K and 50 K components and the new formation of the higher molecular weight intermediates. This observation indicates existence of two processes in chorion hardening, which are tentatively named cadaverine-insensitive and cadaverine-sensitive processes.

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Further Notes on the Hardening of the Chorion of Salmon Eggs

Cited by 14 publications

References 0 publications

Osmotic responses of eggs and larvae of the Pacific herring to salinity and cadmium

Osmotic responses of eggs and larvae of the Pacific herring to salinity and cadmium

Analysis of Hardening of the Egg Envelope (Chorion) of the Fish, Oryzias latipes

Change in Component Proteins of the Egg Envelope (Chorion) of Rainbow Trout during Hardening

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