| 1. |
- Kellner, Martin, 1978-, et al.
(author)
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Developmental exposure to the SSRI citalopram causes long-lasting behavioural effects in the three-spined stickleback (Gasterosteus aculeatus)
- 2018
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In: Ecotoxicology. - : Springer Science and Business Media LLC. - 0963-9292 .- 1573-3017. ; 27:1, s. 12-22
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Journal article (peer-reviewed)abstract
- Selective Serotonin re-uptake inhibitors (SSRIs) are a class of psychotropic drugs used to treat depression in both adolescents and pregnant or breast-feeding mothers as well as in the general population. Recent research on rodents points to long-lasting behavioural effects of pre- and perinatal exposure to SSRIs which last into adulthood. In fish however, studies on effects of developmental exposure to SSRIs appears to be non-existent. In order to study effects of developmental SSRI exposure in fish, three-spine sticklebacks were exposed to 1.5 A mu g/l of the SSRI citalopram in the ambient water for 30 days, starting two days post-fertilisation. After approximately 100 days of remediation in clean water the fish were put through an extensive battery of behavioural tests. Feeding behaviour was tested as the number of bites against a piece of food and found to be increased in the exposed fish. Aggression levels were measured as the number of bites against a mirror image during 10 min and was also found to be significantly increased in the exposed fish. Novel tank behaviour and locomotor activity was tested in an aquarium that had a horizontal line drawn half-way between the bottom and the surface. Neither the latency to the first transition to the upper half, nor the number of transitions or the total time spent in the upper half was affected by treatment. Locomotor activity was significantly reduced in the exposed fish. The light/dark preference was tested in an aquarium where the bottom and walls were black on one side and white on the other. The number of transitions to the white side was significantly reduced in the exposed fish but there was no effect on the latency to the first transition or the total time spent in the white half. The results in the current study indicate that developmental SSRI exposure causes long-lasting behavioural effects in fish and contribute to the existing knowledge about SSRIs as environmental pollutants.
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| 2. |
- Li, Li-Chun, et al.
(author)
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Changes in Red Color Sensitivity over the Spawning Cycle of Female Three-spined Stickleback (Gasterosteus aculeatus)
- 2022
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In: Zoological Studies. - 1021-5506 .- 1810-522X. ; 61
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Journal article (peer-reviewed)abstract
- Male red nuptial coloration is a primary mating signal for three-spined sticklebacks (Gasterosteus aculeatus), and the retinae of both sexes are especially sensitive to red during the breeding season. Red sensitivity is an important aspect of female mate choice in this species, but only when they are ready to spawn and not over the entire breeding period. Here, we aimed to determine if the red sensitivity of female sticklebacks change over their repeat spawning cycle. To this end, we assessed retinal opsin mRNA levels and behavioral red sensitivity in females over this cycle. Both methods indicated that females were more sensitive to red during spawning than in the inter-spawning intervals. Relative expression levels of red color opsin genes (lws) and optical motor sensitivity were high during spawning, decreased after the spawning period, and then increased again 72–96 h later when they were ready to spawn again. Thus, female sticklebacks altered their color sensitivity according to need, but the underlying mechanism remains unclear.
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| 3. |
- Roufidou, Chrysoula, et al.
(author)
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Heat shock protein (HSP) expression and mitogen-activated protein kinase (MAPK) phosphorylation during early embryonic developmental stages of the Gilthead sea bream (Sparus aurata)
- 2018
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In: Mediterranean Marine Science. - : National Documentation Centre (EKT). - 1108-393X .- 1791-6763. ; 19:2, s. 240-247
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Journal article (peer-reviewed)abstract
- Both heat shock proteins (HSPs), which have key roles in vital cell functions, as well as members of the mitogen-activated protein kinases (MAPKs), which adjust gene expression by transducing cellular signals to the nucleus, are necessary for normal embryonic development in vertebrates. Therefore, protein expression levels of HSP70 and HSP90 and the activation of members of the MAPK protein family, such as p38 MAPK, ERKs, and JNKs were studied in the early developmental stages of the Gilthead sea bream, Spams aurata Linnaeus, 1758. The protein expression of HSP70 and the phosphorylation ratio of JNKs remained at equal levels at all examined developmental stages, while the other examined proteins exhibited a differential profile. HSP90 levels were mostly increased at the 16-cell stage and towards the morula stages, and the lowest values were observed at the two- to four-cell and one-half epiboly stages. While p38 MAPK phosphorylation ratio exhibited increased values mostly in the early developmental stages, the opposite was observed concerning ERK phosphorylation ratio, where increased values were observed in the later embryonic stages (high blastula to one-half epiboly stages). These differential profiles of the examined protein expression levels highlight the importance of these proteins during embryogenesis and pave the way for further research to unveil their distinct role in early development.
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| 4. |
- Roufidou, Chrysoula, et al.
(author)
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Hormonal changes over the spawning cycle in the female three-spined stickleback, Gasterosteus aculeatus
- 2018
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In: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 257:SI, s. 97-105
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Journal article (peer-reviewed)abstract
- Female three-spined sticklebacks are batch spawners laying eggs in a nest built by the male. We sampled female sticklebacks at different time points, when they were ready to spawn and 6, 24, 48 and 72 hours post-spawning (hps) with a male. Following spawning, almost all females (15 out of 19) had ovulated eggs again at Day 3 post-spawning (72hps). At sampling, plasma, brain and pituitaries were collected, and the ovary and liver were weighed. Testosterone (T) and estradiol (E2) were measured by radioimmunoassay. Moreover, the mRNA levels of follicle-stimulating hormone (fsh-β) and luteinizing hormone (lh-β) in the pituitary, and of the gonadotropin-releasing hormones (GnRHs: gnrh2, gnrh3) and kisspeptin (kiss2) and its G protein-coupled receptor (gpr54) in the brain were measured by real-time qPCR. Ovarian weights peaked in “ready to spawn” females, dropped after spawning, before again progressively increasing from 6 to 72hps. Plasma T levels showed peaks at 24 and 48hps and decreased at 72hps, while E2 levels increased already at 6hps and remained at high levels up to 48hps. There was a strong positive correlation between T and E2 levels over the spawning cycle. Pituitary lh-β mRNA levels showed a peak at 48hps, while fsh-β did not change. The neuropeptides and gpr54 did not show any changes. The changes in T and E2 over the stickleback spawning cycle were largely consistent with those found in other multiple-spawning fishes whereas the marked correlation between T and E2 does not support T having other major roles over the cycle than being a precursor for E2.
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| 5. |
- Roufidou, Chrysoula, 1987-, et al.
(author)
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Ovarian fluid in the three-spined stickleback, Gasterosteus aculeatus : effects of egg overripening and sex steroid treatment
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Other publication (other academic/artistic)abstract
- In most fishes, including the three-spined stickleback, Gasterosteus aculeatus, the ovulated eggs are surrounded by the ovarian fluid (OF). OF is probably secreted by the ovarian lumen epithelium under stimulation by sex steroids. OF is believed to have several biological functions, including the maintance of the egg viability after ovulation. Female sticklebacks produce eggs in batches, and if spawning or spontaneous dropping of the eggs does not happen, they can become overripe. In the present study, OF properties were studied in overripe and non-overripe ovulated female sticklebacks, and the effects of testosterone (T), estradiol (E2), 17,20β-dihydroxypregn-4-en-3-one (17,20β-P) and progesterone (P4) on OF properties in females that were implanted with Silastic capsules into the abdominal cavity, after having spawned naturally were investigated. Overripe females had a diminished amount of OF, that had a higher percentage dry weight, higher protein levels and lower viscocity compared to OF from non-overripe ovulated females. T delayed the next ovulation. Both T and 17,20β-P induced a significant increase of OF amount. However, the OF protein concentration was significantly increased only in 17,20β-P females. 1-D SDS-PAGE analysis showed that OF contains several proteins, with high individual variability but with no consistent differences between groups. Some of the OF proteins appeared to correspond to proteins from the eggs. The results suggest that secretion of OF may be under the control of 17,20β-P and that changes in its properties are related to the overripening of eggs.
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| 6. |
- Roufidou, Chrysoula, et al.
(author)
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Ovarian fluid in the three-spined stickleback Gasterosteus aculeatus : effects of egg overripening and sex steroid treatment
- 2019
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In: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 94:3, s. 446-457
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Journal article (peer-reviewed)abstract
- The ovarian fluid properties of the three-spined stickleback Gasterosteus aculeatus were studied in overripe and non-overripe ovulated female sticklebacks and in females that were implanted with Silastic capsules containing testosterone (T), oestradiol (E2), 17,20-dihydroxypregn-4-en-3-one (17,20-P) or progesterone (P4) into the abdominal cavity. Overripe females had less ovarian fluid than non-overripe females, but with higher dry mass, higher protein concentration and lower viscosity. T and 17,20-P increased the amount of ovarian fluid and the fluid protein concentration was increased by 17,20-P. 1-D sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that ovarian fluid contains several proteins, with high individual variability but with no consistent differences between groups. Some of the ovarian fluid proteins appeared to correspond to proteins from the eggs. The results suggest that secretion of ovarian fluid may be influenced by steroid hormones and that changes in its properties are related to the overripening of ovulated eggs. In at least some respects it appears that the changes in the ovarian fluid is a result, rather than the cause of overripening.
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| 7. |
- Roufidou, Chrysoula, et al.
(author)
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Overripening of eggs and changes in reproductive hormones in the threespine stickleback, Gasterosteus aculeatus
- 2016
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In: Evolutionary Ecology Research. - 1522-0613 .- 1937-3791. ; 17:3, s. 583-601
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Journal article (peer-reviewed)abstract
- Background: Female threespine sticklebacks, Gasterosteus aculeatus, are batch spawners. As in most teleosts, the ovulated eggs are kept in the ovarian cavity until spawning. If spawning or spontaneous release of the eggs does not take place, they can become overripe and harden, and in most cases remain in the ovary. The overripe eggs are lost for reproduction and also block further spawnings. Reproductive hormones regulate egg production and may be involved in the mechanism of overripening. Question: What are the reproductive endocrinological parameters characterizing overripening of ovulated eggs in the threespine stickleback? Organism: Wild-caught adult threespine sticklebacks from the southern Baltic at Skare in southern Sweden and the island of Asko in northwestern Baltic Proper in Sweden. Experiments: We collected blood samples for hormone measurements, as well as pituitaries and brains for measurement of mRNA from both sexually mature non-overripe (non-ovulated and/or ovulated) and overripe (egg-bound) females. For the Skare fish, sexual maturation was induced under laboratory conditions by exposure to a long photoperiod and we compared the non-overripe (including non-ovulated, with oocytes in different maturing or ripening stages, and ovulated females) with the overripe females. The Asko fish were sampled directly from nature, during the natural summer breeding season and we compared the non-overripe (including non-ovulated, with oocytes in different maturing or ripening stages, and ovulated females) with the overripe females. Methods: In the fish collected from Skare, we used radioimmunoassay to measure the plasma levels of four steroids: testosterone, estradiol, 17,20 beta-dihydroxypregn-4-en-3-one (17,20 beta-P), and 17,20 beta, 21-trihydroxypregn-4-en-3-one (17,20 beta,21-P). We also measured the mRNA levels of gonadotropins [GTHs: follicle-stimulating hormone (fsh-beta) and luteinizing hormone (lh-beta)] in the pituitary, and of gonadotropin-releasing hormones (GnRHs: gnrh2, gnrh3) and kisspeptin (kiss2) and its G protein-coupled receptor (gpr54) in the brain by real-time quantitative PCR. In the fish collected from Asko, we measured only progestogens (17,20 beta-P and 17,20 beta,21-P). Results: In the fish from Skare, overripe female sticklebacks had significantly lower levels of circulating plasma steroid hormones (testosterone, estradiol, 17,20 beta-P), as well as of pituitary lh-beta and brain kiss2 and gpr54 mRNA than the non-overripe females. In the fish caught from Asko, overripe females had lower 17,20 beta-P levels than the non-overripe non-ovulated females, but there was no difference between the non-overripe ovulated and the overripe females. The 17,20 beta,21-P plasma levels were under the limit of detection in all groups.
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| 8. |
- Roufidou, Chrysoula, 1987-
(author)
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Reproductive physiology of the female three-spined stickleback, Gasterosteus aculeatus
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Reproduction in vertebrates, including fishes, is under control of the brain-pituitary-gonad (BPG) axis. The female three-spined stickleback, Gasterosteus aculeatus, produces egg clutches at intervals of a few days and spawns them in a nest built by male. Following ovulation, eggs are stored in the ovarian cavity surrounded by the ovarian fluid (OF). If spawning or spontaneous release do not occur, the eggs can undergo overripening, a phenomenon occurring both in nature and captivity.In this PhD thesis, the changes of reproductive hormones and vitellogenesis were studied at overripening of eggs and over the natural spawning cycle. OF properties were also examined at overripening of eggs and after treatment with sex steroids.Plasma levels of steroids: testosterone (T), estradiol (E2), 17,20β-dihydroxypregn-4-en-3-one (17,20β-P) and 17,20β,21-trihydroxypregn-4-en-3-one (17,20β,21-P) were measured by radioimmunoassay, and relative mRNA levels of the pituitary gonadotropins (fsh-β/lh-β), brain gonadotropin-releasing hormones (gnrh2/gnrh3) and kisspeptin and its receptor (kiss2/gpr54) by qPCR. Overripening of eggs was accompanied with a significant reduction in most of endocrine parameters of BPG axis (T, E2, 17,20β-P; lh-β; kiss2, gpr54). Low level of hormones could be advantageous for the overripe egg-bound females, since this would reduce further ovulations giving higher chances to survive and reproduce again. Over the 3-day spawning cycle, T and E2 were highly correlated, showed cyclicity with low levels at ovulation and increasing from 24 and 6 hours post-spawning (hps), respectively. Spawning may give rise to this increase as these rises did not occur if release of the eggs does not happen (overripe females). A peak at pituitary lh-β mRNA levels appeared 48 hps, a day before the next ovulation. No significant changes were found for the other studied hormones.Vitellogenesis was studied by measurement of the vitellogenin mRNA levels in the liver by qPCR. The levels were highest at 24 and 48 hps and were positively correlated to both E2 and T over the cycle. However, changes were small suggesting a rather continuous vitellogenesis over the stickleback spawning cycle which could be an advantage for a multiple spawner with a limited spawning season. Overripening reduced vitellogenin mRNA levels but did not abolish it.OF amount was diminished in overripe females and had a lower viscocity but higher dry weight and protein levels than in non-overripe ovulated females, suggesting that changes in OF properties are related to the egg overripening. The effects of steroids were studied using Silastic capsules. T and 17,20β-P induced an increase of OF amount, but protein levels were only increased in 17,20β-P-treated females, proposing a role of this steroid in the control of OF secretion. 1-D SDS-PAGE showed that OF contained several proteins, some of them came from eggs, but no consistent differences between groups.Concluding, the knowledge of the reproductive physiological changes is important for understanding their essential roles in the production of viable eggs in this species but also in the reproductive physiology of female fishes in general.
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| 9. |
- Roufidou, Chrysoula, 1987-, et al.
(author)
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Vitellogenesis in the three-spined stickleback, Gasterosteus aculeatus, over the spawning cycle and at egg overripening
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Other publication (other academic/artistic)abstract
- Vitellogenesis was studied in the female three-spined stickleback, Gasterosteus aculeatus, a multiple-spawning fish producing several egg batches during the breeding season, over the spawning cycle and at overripening of eggs. For the spawning cycle, the females were sampled when they were ’’ready to spawn’’ and 6, 24, 48, and 72 hours post-spawning (hps). For the overripening of eggs, non-overripe (mature non-ovulated and ovulated) and overripe females were sampled from nature in the breeding season. Liver tissues were collected for relative vitellogenin mRNA levels measurements by real-time qPCR. vitellogenin mRNA was expressed at all time-points over the 3-day spawning cycle and the levels were significantly increased at 24 and 48 hps, a day before ovulation, compared to the ’’ready to spawn’’ and 6 hps females. Changes over the cycle were, however, small. The highest sample point was only 1.4 times higher than the lowest. The vitellogenin mRNA levels were positively correlated with both circulating estradiol and testosterone levels over the cycle. Overripe females had 1.5 times lower vitellogenin mRNA levels than the non-overripe non-ovulated but not than the non-overripe ovulated females. These findings suggest that vitellogenesis is rather continuous over the stickleback spawning cycle, which could be an advantage for a multiple spawner, and that overripening condition reduces vitellogenin production but does not eliminate it.
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| 10. |
- Shao, Yi Ta, et al.
(author)
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Changes in kisspeptin, GnRH, and gonadotropin mRNA levels in male threespine stickleback (Gasterosteus aculeatus) during photoperiod-induced sexual maturation
- 2019
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In: Evolutionary Ecology Research. - 1522-0613 .- 1937-3791. ; 20:3, s. 317-329
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Journal article (peer-reviewed)abstract
- Background: Both gonadotropin-releasing hormone (GnRH) and kisspeptin have a critical role in the photoperiodic control of sexual maturation in mammals. Question: What are the roles of GnRH and kisspeptin in the photoperiodic control of sexual maturation in the threespine stickleback, Gasterosteus aculeatus? Method: If kisspeptin and GnRH trigger the photoperiodic induction of maturation in fishes, they would be expected to be activated prior to, or at least no later than, the gonadotropins. The mRNA levels of brain gnrh2, gnrh3, kiss2 and its receptor, gpr54, as well as of pituitary lh-beta and fsh-beta, were measured in males under standard laboratory conditions [16 hours light/8 hours dark (L16/D8) or 8 hours light/16 hours dark (L8/D16)] after 3, 10, 19, and 29 days at 20 degrees C. Results: From day 19, males in the long-day photoperiod (L16/D8) condition were visibly mature with bright breeding coloration. Compared with short-day photoperiod (L8/D16) fish, L16/D8 fish had higher lh-beta mRNA levels at days 10, 19, and 29, and higher fsh-beta mRNA levels at day 10 only. Furthermore, L16/D8 fish had higher gnrh3 mRNA levels at days 10 and 29, and higher gnrh2 mRNA levels at day 29, than L8/D16 fish. Finally, kiss2 and gpr54 mRNA levels of L16/D8 fish were significantly higher than those of L8/D16 fish at days 19 and 29, respectively. Conclusions: At the onset of sexual maturation, the levels of lh-beta, fsh-beta, and gnrh3 rose earlier than those of kiss2 and gpr54. These results are consistent with GnRH3 having a role in the early phases of maturation, but do not support a role for kisspeptin in photoperiodic initiation of maturation in male stickleback.
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