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Eggshell and egg yolk proteins in fish: hepatic proteins for the next generation: oogenetic, population, and evolutionary implications of endocrine disruption.

Arukwe A, Goksøyr A - Comp Hepatol (2003)

Bottom Line: The many molecular events involved in these processes require tight, coordinated regulation that is under strict endocrine control, with the female sex steroid hormone estradiol-17beta in a central role.This has led to the development of specific and sensitive assays for these proteins in fish, and the application of vitellogenin and zona radiata proteins as informative biomarkers for endocrine disrupting effects of chemicals and effluents using fish as test organisms.The genes encoding these important reproductive proteins are conserved in the animal kingdom and are products of several hundred million years of evolution.

View Article: PubMed Central - HTML - PubMed

Affiliation: Great Lakes Institute for Environmental Research, University of Windsor, Ontario, 401 Sunset Avenue, Windsor, N9B 3P4, Canada. arukwe@uwindsor.ca

ABSTRACT
The oocyte is the starting point for a new generation. Most of the machinery for DNA and protein synthesis needed for the developing embryo is made autonomously by the fertilized oocyte. However, in fish and in many other oviparous vertebrates, the major constituents of the egg, i.e. yolk and eggshell proteins, are synthesized in the liver and transported to the oocyte for uptake. Vitellogenesis, the process of yolk protein (vitellogenin) synthesis, transport, and uptake into the oocyte, and zonagenesis, the synthesis of eggshell zona radiata proteins, their transport and deposition by the maturing oocyte, are important aspects of oogenesis. The many molecular events involved in these processes require tight, coordinated regulation that is under strict endocrine control, with the female sex steroid hormone estradiol-17beta in a central role. The ability of many synthetic chemical compounds to mimic this estrogen can lead to unscheduled hepatic synthesis of vitellogenin and zona radiata proteins, with potentially detrimental effects to the adult, the egg, the developing embryo and, hence, to the recruitment to the fish population. This has led to the development of specific and sensitive assays for these proteins in fish, and the application of vitellogenin and zona radiata proteins as informative biomarkers for endocrine disrupting effects of chemicals and effluents using fish as test organisms. The genes encoding these important reproductive proteins are conserved in the animal kingdom and are products of several hundred million years of evolution.

No MeSH data available.


Related in: MedlinePlus

Immunochemical analysis using indirect ELISA of oogenic proteins in plasma of juvenile Atlantic salmon (Salmo salar) exposed to different concentrations of oil refinery treatment plant (ORTP) effluent. Proteins were detected with homologous antisera against Atlantic salmon zona radiata proteins (Zr-protein) and vitellogenin (Vtg). Data are given as mean ELISA absorbance values (492 nm) ± SD (n = 6 per treatment group). Data were analyzed using Dunnett's tests for comparison with control group. *Significantly different from control (p < 0.001). Reproduced with permission from Arukwe et al. [113].
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Figure 4: Immunochemical analysis using indirect ELISA of oogenic proteins in plasma of juvenile Atlantic salmon (Salmo salar) exposed to different concentrations of oil refinery treatment plant (ORTP) effluent. Proteins were detected with homologous antisera against Atlantic salmon zona radiata proteins (Zr-protein) and vitellogenin (Vtg). Data are given as mean ELISA absorbance values (492 nm) ± SD (n = 6 per treatment group). Data were analyzed using Dunnett's tests for comparison with control group. *Significantly different from control (p < 0.001). Reproduced with permission from Arukwe et al. [113].

Mentions: In designing a bioassay for xenoestrogens, toxicologists and biologists have used the induction of Vtg and Zr-protein in male and juvenile oviparous vertebrates as an effective and sensitive biomarker for xenoestrogens [113-118]. Using juvenile Atlantic salmon (Salmo salar) and different doses of NP, we saw that NP treatment significantly elevated plasma levels of Zr-protein and Vtg in a two week in vivo study, with the former showing more sensitivity to the xenoestrogen compound [115]. Higher sensitivity of Zr-protein when compared with Vtg evaluated with indirect ELISA has also been observed in with juvenile Atlantic salmon treated with different doses of an oil refinery treatment plant effluent [[115], Fig. 4] and with E2 [119]. In both these studies, induced Zr-protein levels were apparent at lower E2 doses, while Vtg was only induced at higher E2 doses, thus indicating differential induction of both proteins as was observed using NP [115]. However, it could be argued that the differences in sensitivity could arise from different affinities of the antibodies used in the assays. Attempts to resolve this issue have focused on the development of quantitative assays for the two protein groups and their mRNAs (see below). In a recent study with medaka, Lee et al. [51] reported a differential sensitivity of the two zona radiata precursor genes choriogenin H and L, respectively, with choriogenin L mRNA responding at lower doses of estrogen than mRNA of the H form. Unfortunately, however, they did not compare the response directly with Vtg mRNA. In the study of Yadetie et al. [120], no clear differences were observed in the response of Vtg and Zrp mRNA levels of salmon exposed to NP. However, Celius et al. [57], employing a quantitative real time polymerase chain reaction assay (qPCR) for rainbow trout Vtg and Zrp, reported that Zrp mRNA was more responsive than Vtg mRNA to low doses of E2 and the mycoestrogen α-zearalenol.


Eggshell and egg yolk proteins in fish: hepatic proteins for the next generation: oogenetic, population, and evolutionary implications of endocrine disruption.

Arukwe A, Goksøyr A - Comp Hepatol (2003)

Immunochemical analysis using indirect ELISA of oogenic proteins in plasma of juvenile Atlantic salmon (Salmo salar) exposed to different concentrations of oil refinery treatment plant (ORTP) effluent. Proteins were detected with homologous antisera against Atlantic salmon zona radiata proteins (Zr-protein) and vitellogenin (Vtg). Data are given as mean ELISA absorbance values (492 nm) ± SD (n = 6 per treatment group). Data were analyzed using Dunnett's tests for comparison with control group. *Significantly different from control (p < 0.001). Reproduced with permission from Arukwe et al. [113].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC153486&req=5

Figure 4: Immunochemical analysis using indirect ELISA of oogenic proteins in plasma of juvenile Atlantic salmon (Salmo salar) exposed to different concentrations of oil refinery treatment plant (ORTP) effluent. Proteins were detected with homologous antisera against Atlantic salmon zona radiata proteins (Zr-protein) and vitellogenin (Vtg). Data are given as mean ELISA absorbance values (492 nm) ± SD (n = 6 per treatment group). Data were analyzed using Dunnett's tests for comparison with control group. *Significantly different from control (p < 0.001). Reproduced with permission from Arukwe et al. [113].
Mentions: In designing a bioassay for xenoestrogens, toxicologists and biologists have used the induction of Vtg and Zr-protein in male and juvenile oviparous vertebrates as an effective and sensitive biomarker for xenoestrogens [113-118]. Using juvenile Atlantic salmon (Salmo salar) and different doses of NP, we saw that NP treatment significantly elevated plasma levels of Zr-protein and Vtg in a two week in vivo study, with the former showing more sensitivity to the xenoestrogen compound [115]. Higher sensitivity of Zr-protein when compared with Vtg evaluated with indirect ELISA has also been observed in with juvenile Atlantic salmon treated with different doses of an oil refinery treatment plant effluent [[115], Fig. 4] and with E2 [119]. In both these studies, induced Zr-protein levels were apparent at lower E2 doses, while Vtg was only induced at higher E2 doses, thus indicating differential induction of both proteins as was observed using NP [115]. However, it could be argued that the differences in sensitivity could arise from different affinities of the antibodies used in the assays. Attempts to resolve this issue have focused on the development of quantitative assays for the two protein groups and their mRNAs (see below). In a recent study with medaka, Lee et al. [51] reported a differential sensitivity of the two zona radiata precursor genes choriogenin H and L, respectively, with choriogenin L mRNA responding at lower doses of estrogen than mRNA of the H form. Unfortunately, however, they did not compare the response directly with Vtg mRNA. In the study of Yadetie et al. [120], no clear differences were observed in the response of Vtg and Zrp mRNA levels of salmon exposed to NP. However, Celius et al. [57], employing a quantitative real time polymerase chain reaction assay (qPCR) for rainbow trout Vtg and Zrp, reported that Zrp mRNA was more responsive than Vtg mRNA to low doses of E2 and the mycoestrogen α-zearalenol.

Bottom Line: The many molecular events involved in these processes require tight, coordinated regulation that is under strict endocrine control, with the female sex steroid hormone estradiol-17beta in a central role.This has led to the development of specific and sensitive assays for these proteins in fish, and the application of vitellogenin and zona radiata proteins as informative biomarkers for endocrine disrupting effects of chemicals and effluents using fish as test organisms.The genes encoding these important reproductive proteins are conserved in the animal kingdom and are products of several hundred million years of evolution.

View Article: PubMed Central - HTML - PubMed

Affiliation: Great Lakes Institute for Environmental Research, University of Windsor, Ontario, 401 Sunset Avenue, Windsor, N9B 3P4, Canada. arukwe@uwindsor.ca

ABSTRACT
The oocyte is the starting point for a new generation. Most of the machinery for DNA and protein synthesis needed for the developing embryo is made autonomously by the fertilized oocyte. However, in fish and in many other oviparous vertebrates, the major constituents of the egg, i.e. yolk and eggshell proteins, are synthesized in the liver and transported to the oocyte for uptake. Vitellogenesis, the process of yolk protein (vitellogenin) synthesis, transport, and uptake into the oocyte, and zonagenesis, the synthesis of eggshell zona radiata proteins, their transport and deposition by the maturing oocyte, are important aspects of oogenesis. The many molecular events involved in these processes require tight, coordinated regulation that is under strict endocrine control, with the female sex steroid hormone estradiol-17beta in a central role. The ability of many synthetic chemical compounds to mimic this estrogen can lead to unscheduled hepatic synthesis of vitellogenin and zona radiata proteins, with potentially detrimental effects to the adult, the egg, the developing embryo and, hence, to the recruitment to the fish population. This has led to the development of specific and sensitive assays for these proteins in fish, and the application of vitellogenin and zona radiata proteins as informative biomarkers for endocrine disrupting effects of chemicals and effluents using fish as test organisms. The genes encoding these important reproductive proteins are conserved in the animal kingdom and are products of several hundred million years of evolution.

No MeSH data available.


Related in: MedlinePlus