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Avshalom Hurvitz - One of the best experts on this subject based on the ideXlab platform.

  • molecular characterization of kisspeptin receptors and gene expression analysis during oogenesis in the Russian Sturgeon acipenser gueldenstaedtii
    General and Comparative Endocrinology, 2021
    Co-Authors: Ishwar Atre, Avshalom Hurvitz, Gad Degani, Naama Mizrahi, Krist Hausken, Svetlana Yomdin, Berta Levavisivan
    Abstract:

    Sturgeons belong to a subclass of fishes that derived from ray-finned fish ancestors preceding the emergence of teleosts. The Russian Sturgeon (Acipenser gueldenstaedtii) is a late-maturing fish with the females reaching puberty under aquaculture conditions at 6-10 years of age. Since kisspeptin has been shown to be a key hormone involved in regulation of major reproductive processes of many vertebrate species, this study was conducted to better understand the kisspeptin receptor (KissR) in Sturgeon. In this study we have cloned Russian Sturgeon KissR1 from brain mRNA and observed the ontogeny of rsKissR1 mRNA expression in ovarian follicles. Multiple sequence alignment of KissR1, KissR4, and their orthologs revealed that the Russian Sturgeon (rs) KissR1 sequence shares 64%-77% identity with elephant shark, coelacanth, and gar and 44-58% identity with tetrapod and teleost KissR1 sequences, while KissR4 seemed to share <65% identity to eel KissR2 and ~57% identity to Perciformes and Cypriniformes. Further rsKissR4 showed <97% identity to reed fish KissR4, <63% with Squamata (Reptiles) and gar KissR4. A phylogenetic analysis revealed that rsKissR1 is more closely related to coelacanth and gar KissR1 than teleost, while rsKissR4 was part of the KissR4 clade and shared higher similarity with Actinopterygiian sequences. We have further predicted homology models for both rsKiss receptors and performed in-silico analyses of their binding to a kiss-10 peptide. Both Sturgeon and zebrafish Kiss1 and Kiss2 activated rsKissR1 via both PKC/Ca2+ and PKA/cAMP signal-transduction pathways, while rsKissR2 was found to be less effective and was not activated by stKiss peptides. Ovarian rsKissR transcript levels for 10 fishes were determined by real-time PCR and significantly increased concomitantly with oogenesis, where the highest level of expression was evident in black follicles. These data suggest that extra-neuronal expression of the kisspeptin receptor may be involved in Sturgeon reproduction in a manner dependent on reproductive development.

  • Sex-Based Variation of Gene Expression in the Gonads and Fins of Russian Sturgeon (Acipenser gueldenstaedtii)
    Open Journal of Animal Sciences, 2021
    Co-Authors: Gad Degani, Akram Hajouj, Avshalom Hurvitz
    Abstract:

    Russian Sturgeon (Acipenser gueldenstaedtii) is a primitive freshwater fish and a source of black caviar. The genes involved in sexual determination and differentiation are still unknown and there are no molecular markers for sex identification in this species. Studying the variation of the sex-based differences in genomic sequences and in gene expression in the Sturgeon may lead to markers of sex in early stages of development and advances in aquaculture, as well as provide novel insights about the evolution of reproduction, sex determination, and sexual differentiation mechanisms in vertebrates. Previous studies by our and other groups have identified differentially expressed genes in the gonads of adult female and male Sturgeon. The current study aimed to test whether these genes were also differentially expressed in non-gonadal tissue, namely fins. We measured by qRT-PCR the mRNA levels of 29 known and novel sex-related genes in the gonads and fins of males (4 years old) and females (7 years old; sexual maturation is earlier in males than in females). Six genes (ATP6, IGFRM, LIA1A, S1A, NPL1A, GAPDH and SOX9) showed higher expression in female fins. However, only ATP6 mRNA levels differed in fins of males and females of the same age (4 years old). These findings underscore the impracticality of sex identification based on gene expression in non-gonadal tissue and the need for genetic sex markers in the Russian Sturgeon.

  • Molecular characterization of kisspeptin receptors and gene expression analysis during oogenesis in the Russian Sturgeon (Acipenser gueldenstaedtii)
    General and comparative endocrinology, 2020
    Co-Authors: Ishwar Atre, Svetlana Yom-din, Avshalom Hurvitz, Gad Degani, Naama Mizrahi, Krist Hausken, Berta Levavi-sivan
    Abstract:

    Sturgeons belong to a subclass of fishes that derived from ray-finned fish ancestors preceding the emergence of teleosts. The Russian Sturgeon (Acipenser gueldenstaedtii) is a late-maturing fish with the females reaching puberty under aquaculture conditions at 6-10 years of age. Since kisspeptin has been shown to be a key hormone involved in regulation of major reproductive processes of many vertebrate species, this study was conducted to better understand the kisspeptin receptor (KissR) in Sturgeon. In this study we have cloned Russian Sturgeon KissR1 from brain mRNA and observed the ontogeny of rsKissR1 mRNA expression in ovarian follicles. Multiple sequence alignment of KissR1, KissR4, and their orthologs revealed that the Russian Sturgeon (rs) KissR1 sequence shares 64%-77% identity with elephant shark, coelacanth, and gar and 44-58% identity with tetrapod and teleost KissR1 sequences, while KissR4 seemed to share

  • Transcription of Insulin-like Growth Factor Receptor in Russian Sturgeon (Acipenser gueldenstaedtii) Ovary during Oogenesis
    Universal Journal of Agricultural Research, 2017
    Co-Authors: Gad Degani, S. Yom Din, Avshalom Hurvitz
    Abstract:

    In the present study, we examined the insulin-like growth factor receptor 1(IGF-1R) transcription using real-time PCR at different stages of oocytes of Russian Sturgeon (Acipenser gueldenstaedtii) at age 8-9 years and weight 25 kg that were grown under aquaculture conditions. Compare to the pre-vitellogenesis stage, the transcription of IGF-1R increased at the vitellogenesis stages (yellow, gray and black). The mRNA of IGF-1R of oocytes in the black stage is significantly higher than in the gray or yellow stages. However, there are no significant differences between the gray or yellow stages of the mRNA level. Based on previous studies and the result of the mRNA of IGF-1R of oocytes during oogenesis, we proposed a model for the effect of GH, IGF-1 and IGF-1R on the oogenesis of Russian Sturgeon, which is a very important process for creating caviar.

  • Vitellogenin Level in the Plasma of Russian Sturgeon ( Acipenser gueldenstaedtii ) Northern Israel
    Journal of Marine Science: Research & Development, 2017
    Co-Authors: Berta Levavi-sivan, Gad Degani, Avshalom Hurvitz
    Abstract:

    In the present study, we examined the vitellogenin (Vg) level of Russian Sturgeon maintained in a relatively constant aquaculture at a water temperature of 18-22°C during growth and maturation. An increase in Vg in the blood plasma from oocytes was found in the yellow oocytes stage to the gray oocytes stage. However, no Vg was found in the pre-vitellogenic stage. Based on the present study and previous studies on hormone control reproduction and growth, we proposed a quality model that correlated between egg development and the hormones involved in controlling vitelogenesis (VTL).

Berta Levavi-sivan - One of the best experts on this subject based on the ideXlab platform.

Gad Degani - One of the best experts on this subject based on the ideXlab platform.

  • molecular characterization of kisspeptin receptors and gene expression analysis during oogenesis in the Russian Sturgeon acipenser gueldenstaedtii
    General and Comparative Endocrinology, 2021
    Co-Authors: Ishwar Atre, Avshalom Hurvitz, Gad Degani, Naama Mizrahi, Krist Hausken, Svetlana Yomdin, Berta Levavisivan
    Abstract:

    Sturgeons belong to a subclass of fishes that derived from ray-finned fish ancestors preceding the emergence of teleosts. The Russian Sturgeon (Acipenser gueldenstaedtii) is a late-maturing fish with the females reaching puberty under aquaculture conditions at 6-10 years of age. Since kisspeptin has been shown to be a key hormone involved in regulation of major reproductive processes of many vertebrate species, this study was conducted to better understand the kisspeptin receptor (KissR) in Sturgeon. In this study we have cloned Russian Sturgeon KissR1 from brain mRNA and observed the ontogeny of rsKissR1 mRNA expression in ovarian follicles. Multiple sequence alignment of KissR1, KissR4, and their orthologs revealed that the Russian Sturgeon (rs) KissR1 sequence shares 64%-77% identity with elephant shark, coelacanth, and gar and 44-58% identity with tetrapod and teleost KissR1 sequences, while KissR4 seemed to share <65% identity to eel KissR2 and ~57% identity to Perciformes and Cypriniformes. Further rsKissR4 showed <97% identity to reed fish KissR4, <63% with Squamata (Reptiles) and gar KissR4. A phylogenetic analysis revealed that rsKissR1 is more closely related to coelacanth and gar KissR1 than teleost, while rsKissR4 was part of the KissR4 clade and shared higher similarity with Actinopterygiian sequences. We have further predicted homology models for both rsKiss receptors and performed in-silico analyses of their binding to a kiss-10 peptide. Both Sturgeon and zebrafish Kiss1 and Kiss2 activated rsKissR1 via both PKC/Ca2+ and PKA/cAMP signal-transduction pathways, while rsKissR2 was found to be less effective and was not activated by stKiss peptides. Ovarian rsKissR transcript levels for 10 fishes were determined by real-time PCR and significantly increased concomitantly with oogenesis, where the highest level of expression was evident in black follicles. These data suggest that extra-neuronal expression of the kisspeptin receptor may be involved in Sturgeon reproduction in a manner dependent on reproductive development.

  • Sex-Based Variation of Gene Expression in the Gonads and Fins of Russian Sturgeon (Acipenser gueldenstaedtii)
    Open Journal of Animal Sciences, 2021
    Co-Authors: Gad Degani, Akram Hajouj, Avshalom Hurvitz
    Abstract:

    Russian Sturgeon (Acipenser gueldenstaedtii) is a primitive freshwater fish and a source of black caviar. The genes involved in sexual determination and differentiation are still unknown and there are no molecular markers for sex identification in this species. Studying the variation of the sex-based differences in genomic sequences and in gene expression in the Sturgeon may lead to markers of sex in early stages of development and advances in aquaculture, as well as provide novel insights about the evolution of reproduction, sex determination, and sexual differentiation mechanisms in vertebrates. Previous studies by our and other groups have identified differentially expressed genes in the gonads of adult female and male Sturgeon. The current study aimed to test whether these genes were also differentially expressed in non-gonadal tissue, namely fins. We measured by qRT-PCR the mRNA levels of 29 known and novel sex-related genes in the gonads and fins of males (4 years old) and females (7 years old; sexual maturation is earlier in males than in females). Six genes (ATP6, IGFRM, LIA1A, S1A, NPL1A, GAPDH and SOX9) showed higher expression in female fins. However, only ATP6 mRNA levels differed in fins of males and females of the same age (4 years old). These findings underscore the impracticality of sex identification based on gene expression in non-gonadal tissue and the need for genetic sex markers in the Russian Sturgeon.

  • Molecular characterization of kisspeptin receptors and gene expression analysis during oogenesis in the Russian Sturgeon (Acipenser gueldenstaedtii)
    General and comparative endocrinology, 2020
    Co-Authors: Ishwar Atre, Svetlana Yom-din, Avshalom Hurvitz, Gad Degani, Naama Mizrahi, Krist Hausken, Berta Levavi-sivan
    Abstract:

    Sturgeons belong to a subclass of fishes that derived from ray-finned fish ancestors preceding the emergence of teleosts. The Russian Sturgeon (Acipenser gueldenstaedtii) is a late-maturing fish with the females reaching puberty under aquaculture conditions at 6-10 years of age. Since kisspeptin has been shown to be a key hormone involved in regulation of major reproductive processes of many vertebrate species, this study was conducted to better understand the kisspeptin receptor (KissR) in Sturgeon. In this study we have cloned Russian Sturgeon KissR1 from brain mRNA and observed the ontogeny of rsKissR1 mRNA expression in ovarian follicles. Multiple sequence alignment of KissR1, KissR4, and their orthologs revealed that the Russian Sturgeon (rs) KissR1 sequence shares 64%-77% identity with elephant shark, coelacanth, and gar and 44-58% identity with tetrapod and teleost KissR1 sequences, while KissR4 seemed to share

  • Transcription of Insulin-like Growth Factor Receptor in Russian Sturgeon (Acipenser gueldenstaedtii) Ovary during Oogenesis
    Universal Journal of Agricultural Research, 2017
    Co-Authors: Gad Degani, S. Yom Din, Avshalom Hurvitz
    Abstract:

    In the present study, we examined the insulin-like growth factor receptor 1(IGF-1R) transcription using real-time PCR at different stages of oocytes of Russian Sturgeon (Acipenser gueldenstaedtii) at age 8-9 years and weight 25 kg that were grown under aquaculture conditions. Compare to the pre-vitellogenesis stage, the transcription of IGF-1R increased at the vitellogenesis stages (yellow, gray and black). The mRNA of IGF-1R of oocytes in the black stage is significantly higher than in the gray or yellow stages. However, there are no significant differences between the gray or yellow stages of the mRNA level. Based on previous studies and the result of the mRNA of IGF-1R of oocytes during oogenesis, we proposed a model for the effect of GH, IGF-1 and IGF-1R on the oogenesis of Russian Sturgeon, which is a very important process for creating caviar.

  • Vitellogenin Level in the Plasma of Russian Sturgeon ( Acipenser gueldenstaedtii ) Northern Israel
    Journal of Marine Science: Research & Development, 2017
    Co-Authors: Berta Levavi-sivan, Gad Degani, Avshalom Hurvitz
    Abstract:

    In the present study, we examined the vitellogenin (Vg) level of Russian Sturgeon maintained in a relatively constant aquaculture at a water temperature of 18-22°C during growth and maturation. An increase in Vg in the blood plasma from oocytes was found in the yellow oocytes stage to the gray oocytes stage. However, no Vg was found in the pre-vitellogenic stage. Based on the present study and previous studies on hormone control reproduction and growth, we proposed a quality model that correlated between egg development and the hormones involved in controlling vitelogenesis (VTL).

Berta Levavisivan - One of the best experts on this subject based on the ideXlab platform.

  • molecular characterization of kisspeptin receptors and gene expression analysis during oogenesis in the Russian Sturgeon acipenser gueldenstaedtii
    General and Comparative Endocrinology, 2021
    Co-Authors: Ishwar Atre, Avshalom Hurvitz, Gad Degani, Naama Mizrahi, Krist Hausken, Svetlana Yomdin, Berta Levavisivan
    Abstract:

    Sturgeons belong to a subclass of fishes that derived from ray-finned fish ancestors preceding the emergence of teleosts. The Russian Sturgeon (Acipenser gueldenstaedtii) is a late-maturing fish with the females reaching puberty under aquaculture conditions at 6-10 years of age. Since kisspeptin has been shown to be a key hormone involved in regulation of major reproductive processes of many vertebrate species, this study was conducted to better understand the kisspeptin receptor (KissR) in Sturgeon. In this study we have cloned Russian Sturgeon KissR1 from brain mRNA and observed the ontogeny of rsKissR1 mRNA expression in ovarian follicles. Multiple sequence alignment of KissR1, KissR4, and their orthologs revealed that the Russian Sturgeon (rs) KissR1 sequence shares 64%-77% identity with elephant shark, coelacanth, and gar and 44-58% identity with tetrapod and teleost KissR1 sequences, while KissR4 seemed to share <65% identity to eel KissR2 and ~57% identity to Perciformes and Cypriniformes. Further rsKissR4 showed <97% identity to reed fish KissR4, <63% with Squamata (Reptiles) and gar KissR4. A phylogenetic analysis revealed that rsKissR1 is more closely related to coelacanth and gar KissR1 than teleost, while rsKissR4 was part of the KissR4 clade and shared higher similarity with Actinopterygiian sequences. We have further predicted homology models for both rsKiss receptors and performed in-silico analyses of their binding to a kiss-10 peptide. Both Sturgeon and zebrafish Kiss1 and Kiss2 activated rsKissR1 via both PKC/Ca2+ and PKA/cAMP signal-transduction pathways, while rsKissR2 was found to be less effective and was not activated by stKiss peptides. Ovarian rsKissR transcript levels for 10 fishes were determined by real-time PCR and significantly increased concomitantly with oogenesis, where the highest level of expression was evident in black follicles. These data suggest that extra-neuronal expression of the kisspeptin receptor may be involved in Sturgeon reproduction in a manner dependent on reproductive development.

  • use of endoscopy for gender and ovarian stage determinations in Russian Sturgeon acipenser gueldenstaedtii grown in aquaculture
    Aquaculture, 2007
    Co-Authors: Avshalom Hurvitz, Gad Degani, K Jackson, Berta Levavisivan
    Abstract:

    The Russian Sturgeon (Acipenser gueldenstaedtii) is native to the Caspian Sea, the Black Sea and the Azov Sea. It used to breed in the main incoming rivers, until dam construction in the mid 20th century blocked upriver spawning migration. Aquaculture of Russian Sturgeon has only recently begun, prompted by their declining populations in natural habitats and the rise in meat and caviar prices. However, information on their gonadal development and puberty under culture conditions is incomplete. Because Sturgeons have no external sexual dimorphism and there are no external markers for sexing, internal examination of the gonads must be employed for gender identification as well as to monitor their development. The present study describes endoscopic and histological observations of the gonads of young Russian Sturgeons aimed at identifying gender and monitoring ovarian developmental stage in females up to the age of 6 years, when they enter their first puberty cycle, as well as at 7 years of age, when they have completed vitellogenesis, under culture conditions. This information, as related to fish age and size, is of vital importance to commercial farming of Russian Sturgeon for caviar production and reproduction. Forgonadalobservationsinbothsexes,weusedanendoscopicsystemconsistingofa4mm,14cmlongcystoscopesheathincorporated with fiber-optic light transmission, connected to a halogen cold light source and a miniature videocamera with a control unit attached to a color monitor. This system allowed us viewing of the fish's abdominal organs, and to save pictures of selected areas of the gonads on a computer as the fish's personal record. Ovarian biopsies were taken in parallel for histology at typical stages of gonadal development. Gender could be identified with this system as early as at 3 years of age and the sex ratio under culture conditions of females, males and unidentified gender were 55, 40 and 5%, respectively. Not only did large differences occur in the developmental stages of female of the same age group, but also ovarian development was highly asynchronous at the early vitellogenic stages. In late vitellogenesis, at the “gray egg” stage (1600–2600 μm diameter), the oocytes were quite regular in size and color, and remained so until the final stages of maturity. Our study suggests that endoscopy is an efficient method for both gender identification at an early age, and for determination of gonadal development stage in Sturgeon aquaculture. The ability to see the whole intact gonads of anesthetized fish can reveal important management and research information, with minimal damage or stress to the fish. © 2007 Published by Elsevier B.V.

Chulhong Park - One of the best experts on this subject based on the ideXlab platform.

  • Ontogenetic behavior of farm-bred Russian Sturgeon (Acipenser gueldenstaedtii) prelarvae in a diel photoperiodic cycle: behavioral modifications in response to light intensity
    Fisheries and Aquatic Sciences, 2019
    Co-Authors: Eun Jeong Kim, Chulhong Park, Yoon Kwon Nam
    Abstract:

    Russian Sturgeon ( Acipenser gueldenstaedtii ) is commercially important in Korea because its caviar is highly prized. Although the early ontogeny of the species has been described, behavioral modifications in response to various light intensities or diel photoperiodicity patterns have not been studied extensively. The objective of the present study was to examine the behavioral characteristics of hatchery-produced A. gueldenstaedtii prelarvae over a diel photoperiodic cycle. During a diel light cycle comprising 16 h of daylight (450 lx), 4 h of dim light (10 lx), and 4 h of darkness (

  • ontogenetic behavior of farm bred Russian Sturgeon acipenser gueldenstaedtii prelarvae in a diel photoperiodic cycle behavioral modifications in response to light intensity
    Fisheries and Aquatic Sciences, 2019
    Co-Authors: Eun Jeong Kim, Chulhong Park, Yoon Kwon Nam
    Abstract:

    Russian Sturgeon (Acipenser gueldenstaedtii) is commercially important in Korea because its caviar is highly prized. Although the early ontogeny of the species has been described, behavioral modifications in response to various light intensities or diel photoperiodicity patterns have not been studied extensively. The objective of the present study was to examine the behavioral characteristics of hatchery-produced A. gueldenstaedtii prelarvae over a diel photoperiodic cycle. During a diel light cycle comprising 16 h of daylight (450 lx), 4 h of dim light (10 lx), and 4 h of darkness (< 1 lx), newly hatched A. gueldenstaedtii prelarvae exhibited negative phototaxis in daylight (day 0–day 2), and this early behavior was not significantly affected by changes of light intensities. Rheotactic and non-rheotactic aggregation into schools was typical between days 3 and 6. Under the diel light cycle conditions described, rheotaxis was not influenced by environmental light intensity as much as non-rheotactic schooling behavior. Post-schooling behavior, which progressed from day 7 to day 8, did not change significantly during the diel light cycle. The data from the present study could be of practical value in developing a visual guide for assessing the fitness and quality of Russian Sturgeon prelarvae under diel light cycle conditions in hatcheries.

  • Additional file 1: of Ontogenetic behavior of farm-bred Russian Sturgeon (Acipenser gueldenstaedtii) prelarvae in a diel photoperiodic cycle: behavioral modifications in response to light intensity
    2019
    Co-Authors: Eun Kim, Chulhong Park, Yoon Nam
    Abstract:

    Figure S1. Information on prelarval development of Russian Sturgeon (Acipenser gueldenstaedtii) used in the present study. (PDF 381 kb

  • Effects of incubation temperature on the embryonic viability and hatching time in Russian Sturgeon (Acipenser gueldenstaedtii)
    Fisheries and Aquatic Sciences, 2018
    Co-Authors: Chulhong Park
    Abstract:

    Background Russian Sturgeon ( Acipenser gueldenstaedtii ) is an emerging candidate species in the Korean aquaculture domain owing to its highly valued caviar. Although the embryonic development of this species was previously described, the complete image data on the morphological differentiation of developing embryos have not been yet fully available. Further, with the viewpoint of larval production in hatchery, the effects of temperature on embryonic viability and the temporal window of hatching event have not been extensively studied. Hence, the objective of this study was to provide a complete set of photographic image data on the embryogenesis and also to examine the effects of incubation temperatures on embryonic viability and hatching event in farm-bred Russian Sturgeon. Results Typical characteristics of embryonic development including uneven, holoblastic cleavages with unequal blastomeres, followed by the formation of germ layer, neurulation, and organogenesis until hatching, were documented. Under different temperature conditions (12, 16, or 20 °C), viability of embryos incubated at 12 °C was significantly lower as relative to those of 16 and 20 °C incubated embryos. Hatchability of embryos was higher, and the timing of hatching event was more synchronized at 20 °C than at 12 and 16 °C. Conclusion Data from this study suggest that the incubation of Russian Sturgeon embryos at 20 °C would be desirable in the hatchery practice with respect to the good hatchability of embryos and the synchronization of hatching events. Additionally, the updated image data for complete embryonic development could be a useful reference guide for not only developmental researches but also artificial propagation of Russian Sturgeon in farms.

  • Effects of incubation temperature on the embryonic viability and hatching time in Russian Sturgeon ( Acipenser gueldenstaedtii )
    Fisheries and Aquatic Sciences, 2018
    Co-Authors: Eun Jeong Kim, Chulhong Park, Yoon Kwon Nam
    Abstract:

    Russian Sturgeon (Acipenser gueldenstaedtii) is an emerging candidate species in the Korean aquaculture domain owing to its highly valued caviar. Although the embryonic development of this species was previously described, the complete image data on the morphological differentiation of developing embryos have not been yet fully available. Further, with the viewpoint of larval production in hatchery, the effects of temperature on embryonic viability and the temporal window of hatching event have not been extensively studied. Hence, the objective of this study was to provide a complete set of photographic image data on the embryogenesis and also to examine the effects of incubation temperatures on embryonic viability and hatching event in farm-bred Russian Sturgeon. Typical characteristics of embryonic development including uneven, holoblastic cleavages with unequal blastomeres, followed by the formation of germ layer, neurulation, and organogenesis until hatching, were documented. Under different temperature conditions (12, 16, or 20 °C), viability of embryos incubated at 12 °C was significantly lower as relative to those of 16 and 20 °C incubated embryos. Hatchability of embryos was higher, and the timing of hatching event was more synchronized at 20 °C than at 12 and 16 °C. Data from this study suggest that the incubation of Russian Sturgeon embryos at 20 °C would be desirable in the hatchery practice with respect to the good hatchability of embryos and the synchronization of hatching events. Additionally, the updated image data for complete embryonic development could be a useful reference guide for not only developmental researches but also artificial propagation of Russian Sturgeon in farms.