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20 pages, 4251 KiB

Open AccessArticle

The Effects of Seven-Day Exposure to Silver Nanoparticles on Fertility and Homeostasis of Zebrafish (Danio rerio)

by Hubert Szudrowicz, Maciej Kamaszewski, Antoni Adamski, Marek Skrobisz, Justyna Frankowska-Łukawska, Maciej Wójcik, Joanna Bochenek, Kacper Kawalski, Jakub Martynow, Patryk Bujarski, Pola Pruchniak, Ewelina Latoszek, Paweł Bury-Burzymski, Adrian Szczepański, Sławomir Jaworski, Arkadiusz Matuszewski and Andrzej Przemysław Herman

Int. J. Mol. Sci. 2022, 23(19), 11239; https://doi.org/10.3390/ijms231911239 - 24 Sep 2022

Cited by 5 | Viewed by 1995

Abstract

Silver nanoparticles (AgNPs) are found in open waters, but the effect of their low concentrations on an organism’s homeostasis is not fully understood. The aim of the study was to determine the short-term exposure effects of AgNPs coated by PvP (polyvinylpyrrolidone) on the [...] Read more.

Silver nanoparticles (AgNPs) are found in open waters, but the effect of their low concentrations on an organism’s homeostasis is not fully understood. The aim of the study was to determine the short-term exposure effects of AgNPs coated by PvP (polyvinylpyrrolidone) on the homeostasis of livers and gonads in zebrafish. Sexually mature zebrafish were exposed for seven days to silver ions (0.01 mg/dm³) or AgNPs (0.01; 0.05; 0.1; 0.5; 1.0 mg/dm³). On the last day, the liver, testes, and ovaries were subjected to a histology analysis. In the liver, we analyzed the expression of the cat, gpx1a, gsr, sod1, and cyp1a genes. On the last day of the experiment, the lowest survival rate was found in the AgNPs 0.05 mg/dm³ group. The histological analysis showed that AgNPs and silver ions cause an increase in the area of hepatocytes. The highest proliferation index of hepatocytes was found in the AgNP 0.05 mg/dm³ group. Furthermore, AgNPs were found to interfere with spermatogenesis and oogonesis as well as reduce the expression levels of the cat, gpx1a, and sod1 genes in the liver compared with the control group. Based on the results, it can be concluded that exposure to AgNPs causes cytotoxic changes in zebrafish, activates the immune system, negatively affects the process of meiosis in the gonads, and generates oxidative stress. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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15 pages, 3338 KiB

Open AccessArticle

Whole-Genome Inter-Sex Variation in Russian Sturgeon (Acipenser gueldenstaedtii)

by Gad Degani, Michal Nevo Sarel, Akram Hajouj, Avshalom Hurvitz, Isana Veksler-Lublinsky and Ari Meerson

Int. J. Mol. Sci. 2022, 23(16), 9469; https://doi.org/10.3390/ijms23169469 - 22 Aug 2022

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Abstract

The Russian sturgeon (Acipenser gueldenstaedtii, AG) is an endangered fish species increasingly raised on fish farms for black caviar. Understanding the process of sex determination in AG is, therefore, of scientific and commercial importance. AG lacks sexual dimorphism until sexual maturation [...] Read more.

The Russian sturgeon (Acipenser gueldenstaedtii, AG) is an endangered fish species increasingly raised on fish farms for black caviar. Understanding the process of sex determination in AG is, therefore, of scientific and commercial importance. AG lacks sexual dimorphism until sexual maturation and has a predominantly octoploid genome without a definite sex chromosome. A conserved short female-specific genomic sequence was recently described, leading to the development of a genetic sex marker. However, no biological function has been reported for this sequence. Thus, the mechanism of sex determination and the overall inter-sex genomic variation in AG are still unknown. To comprehensively analyze the inter-sex genomic variation and assess the overall inter-species variation between AG and A. ruthenus (AR, sterlet), a related tetraploid sturgeon species, we performed whole-genome sequencing on DNA from 10 fish-farm-raised adult AG (5 males and 5 females). We produced a partially assembled, ~2390 MBp draft genome for AG. We validated in AG the female-specific region previously described in AR. We identified ~2.8 million loci (SNP/indels) varying between the species, but only ~7400 sex-associated loci in AG. We mapped the sex-associated AG loci to the AR genome and identified 15 peaks of sex-associated variation (10 kb segments with 30 or more sex-associated variants), 1 of which matched the previously reported sex-variable region. Finally, we identified 14 known and predicted genes in proximity to these peaks. Our analysis suggests that one or more of these genes may have functional roles in sex determination and/or sexual differentiation in sturgeons. Further functional studies are required to elucidate these roles. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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17 pages, 9221 KiB

Open AccessArticle

Transcriptome Profiling and Expression Localization of Key Sex-Related Genes in a Socially-Controlled Hermaphroditic Clownfish, Amphiprion clarkii

by Huan Wang, Meng Qu, Wei Tang, Shufang Liu and Shaoxiong Ding

Int. J. Mol. Sci. 2022, 23(16), 9085; https://doi.org/10.3390/ijms23169085 - 13 Aug 2022

Cited by 6 | Viewed by 2075

Abstract

Clownfish can be an excellent research model for investigating the socially-controlled sexual development of sequential hermaphrodite teleosts. However, the molecular cascades underlying the social cues that orchestrate the sexual development process remain poorly understood. Here, we performed a comparative transcriptomic analysis of gonads [...] Read more.

Clownfish can be an excellent research model for investigating the socially-controlled sexual development of sequential hermaphrodite teleosts. However, the molecular cascades underlying the social cues that orchestrate the sexual development process remain poorly understood. Here, we performed a comparative transcriptomic analysis of gonads from females, males, and nonbreeders of Amphiprion clarkii, which constitute a complete social group, allowing us to investigate the molecular regulatory network under social control. Our analysis highlighted that the gonads of nonbreeders and males exhibited high similarities but were far from females, both in global transcriptomic profiles and histological characteristics, and identified numerous candidate genes involved in sexual development, some well-known and some novel. Significant upregulation of cyp19a1a, foxl2, nr5a1a, wnt4a, hsd3b7, and pgr in females provides strong evidence for the importance of steroidogenesis in ovarian development and maintenance, with cyp19a1a playing a central role. Amh and sox8 are two potential key factors that may regulate testicular tissue development in early and late stages, respectively, as they are expressed at higher levels in males than in females, but with slightly different expression timings. Unlike previous descriptions in other fishes, the unique expression pattern of dmrt1 in A. clarkii implied its potential function in both male and female gonads, and we speculated that it might play promoting roles in the early development of both testicular and ovarian tissues. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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14 pages, 5009 KiB

Open AccessArticle

Cloning of the Maternal Effector Gene org and Its Regulation by lncRNA ORG-AS in Chinese Tongue Sole (Cynoglossus semilaevis)

by Xiaona Zhao, Bo Feng, Qian Wang, Lili Tang, Qian Liu, Wenxiu Ma, Chenghua Li and Changwei Shao

Int. J. Mol. Sci. 2022, 23(15), 8605; https://doi.org/10.3390/ijms23158605 - 03 Aug 2022

Cited by 2 | Viewed by 1517

Abstract

Maternal effector genes (MEGs) encode maternal RNA and protein, accumulating in the cytoplasm of oocytes. During oocyte development, MEGs participate in oocyte meiosis and promote oocyte development. And MEGs can also regulate maternal transcriptome stability and promote maternal–zygotic transition (MTZ) in early embryonic [...] Read more.

Maternal effector genes (MEGs) encode maternal RNA and protein, accumulating in the cytoplasm of oocytes. During oocyte development, MEGs participate in oocyte meiosis and promote oocyte development. And MEGs can also regulate maternal transcriptome stability and promote maternal–zygotic transition (MTZ) in early embryonic development. Long noncoding RNAs (lncRNAs), as new epigenetic regulators, can regulate gene expression at both the transcriptional and post-transcriptional levels through cis- or trans-regulation. The oogenesis-related gene org is a germ-cell-specific gene in fish, but the role of org in embryonic development and oogenesis has rarely been studied, and the knowledge of the lncRNA-mediated regulation of org is limited. In this study, we cloned and identified the org gene of Chinese tongue sole (Cynoglossus semilaevis), and we identified a lncRNA named lncRNA ORG-anti-sequence (ORG-AS), located at the reverse overlapping region of org. The results of qRT-PCR and FISH demonstrated that org was highly expressed during the early stages of embryonic development and oogenesis and was located in the cytoplasm of oocytes. ORG-AS was expressed at low levels in the ovary and colocalized with org in the cytoplasm of oocytes. In vitro experiments showed that overexpression of ORG-AS inhibited org expression. These results suggest that org, as a MEG in C. semilaevis, participates in the MTZ and the oogenesis. The lncRNA ORG-AS negatively regulates the gene expression of org through trans-regulation. These new findings broaden the function of MEGs in embryonic development and the oogenesis of bony fish and prove that lncRNAs are important molecular factors regulating org. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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16 pages, 1504 KiB

Open AccessArticle

Absence of Figla-like Gene Is Concordant with Femaleness in Cichlids Harboring the LG1 Sex-Determination System

by Arie Yehuda Curzon, Andrey Shirak, Ayana Benet-Perlberg, Alon Naor, Shay Israel Low-Tanne, Haled Sharkawi, Micha Ron and Eyal Seroussi

Int. J. Mol. Sci. 2022, 23(14), 7636; https://doi.org/10.3390/ijms23147636 - 11 Jul 2022

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Abstract

Oreochromis niloticus has been used as a reference genome for studies of tilapia sex determination (SD) revealing segregating genetic loci on linkage groups (LGs) 1, 3, and 23. The master key regulator genes (MKR) underlying the SD regions on LGs 3 and 23 [...] Read more.

Oreochromis niloticus has been used as a reference genome for studies of tilapia sex determination (SD) revealing segregating genetic loci on linkage groups (LGs) 1, 3, and 23. The master key regulator genes (MKR) underlying the SD regions on LGs 3 and 23 have been already found. To identify the MKR in fish that segregate for the LG1 XX/XY SD-system, we applied short variant discovery within the sequence reads of the genomic libraries of the Amherst hybrid stock, Coptodon zillii and Sarotherodon galilaeus, which were aligned to a 3-Mbp-region of the O. aureus genome. We obtained 66,372 variants of which six were concordant with the XX/XY model of SD and were conserved across these species, disclosing the male specific figla-like gene. We further validated this observation in O. mossambicus and in the Chitralada hybrid stock. Genome alignment of the 1252-bp transcript showed that the figla-like gene’s size was 2664 bp, and that its three exons were capable of encoding 99 amino acids including a 45-amino-acid basic helix–loop–helix domain that is typical of the ovary development regulator—factor-in-the-germline-alpha (FIGLA). In Amherst gonads, the figla-like gene was exclusively expressed in testes. Thus, the figla-like genomic presence determines male fate by interrupting the female developmental program. This indicates that the figla-like gene is the long-sought SD MKR on LG1. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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14 pages, 3416 KiB

Open AccessArticle

Isolation and Characterization of Germline Stem Cells in Protogynous Hermaphroditic Monopterus albus

by Xiaoyun Sun, Binbin Tao, Yongxin Wang, Wei Hu and Yuhua Sun

Int. J. Mol. Sci. 2022, 23(11), 5861; https://doi.org/10.3390/ijms23115861 - 24 May 2022

Cited by 6 | Viewed by 2301

Abstract

Germline stem cells (GSCs) are a group of unique adult stem cells in gonads that act as important transmitters for genetic information. Donor GSCs have been used to produce offspring by transplantation in fisheries. In this study, we successfully isolated and enriched GSCs [...] Read more.

Germline stem cells (GSCs) are a group of unique adult stem cells in gonads that act as important transmitters for genetic information. Donor GSCs have been used to produce offspring by transplantation in fisheries. In this study, we successfully isolated and enriched GSCs from the ovary, ovotestis, and testis of Monopterus albus, one of the most important breeding freshwater fishes in China. Transcriptome comparison assay suggests that a distinct molecular signature exists in each type of GSC, and that different signaling activities are required for the maintenance of distinct GSCs. Functional analysis shows that fGSCs can successfully colonize and contribute to the germline cell lineage of a host zebrafish gonad after transplantation. Finally, we describe a simple feeder-free method for the isolation and enrichment of GSCs that can contribute to the germline cell lineage of zebrafish embryos and generate the germline chimeras after transplantation. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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14 pages, 2513 KiB

Open AccessArticle

Identification of an Epigenetically Marked Locus within the Sex Determination Region of Channel Catfish

by Yujia Yang, Tao Zhou, Yang Liu, Changxu Tian, Lisui Bao, Wenwen Wang, Yu Zhang, Shikai Liu, Huitong Shi, Suxu Tan, Dongya Gao, Rex A. Dunham and Zhanjiang Liu

Int. J. Mol. Sci. 2022, 23(10), 5471; https://doi.org/10.3390/ijms23105471 - 13 May 2022

Cited by 7 | Viewed by 2225

Abstract

Channel catfish has an XY sex determination system. However, the X and Y chromosomes harbor an identical gene content of 950 genes each. In this study, we conducted comparative analyses of methylome and transcriptome of genetic males and genetic females before gonadal differentiation [...] Read more.

Channel catfish has an XY sex determination system. However, the X and Y chromosomes harbor an identical gene content of 950 genes each. In this study, we conducted comparative analyses of methylome and transcriptome of genetic males and genetic females before gonadal differentiation to provide insights into the mechanisms of sex determination. Differentially methylated CpG sites (DMCs) were predominantly identified on the sex chromosome, most notably within the sex determination region (SDR), although the overall methylation profiles across the entire genome were similar between genetic males and females. The drastic differences in methylation were located within the SDR at nucleotide position 14.0–20.3 Mb of the sex chromosome, making this region an epigenetically marked locus within the sex determination region. Most of the differentially methylated CpG sites were hypermethylated in females and hypomethylated in males, suggesting potential involvement of methylation modification in sex determination in channel catfish. Along with the differential methylation in the SDR, a number of differentially expressed genes within the SDR were also identified between genetic males and females, making them potential candidate genes for sex determination and differentiation in channel catfish. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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12 pages, 2588 KiB

Open AccessBrief Report

Screening of Genes Related to Sex Determination and Differentiation in Mandarin Fish (Siniperca chuatsi)

by Cheng Yang, Liangming Chen, Rong Huang, Bin Gui, Yangyu Li, Yangyang Li, Yongming Li, Lanjie Liao, Zuoyan Zhu and Yaping Wang

Int. J. Mol. Sci. 2022, 23(14), 7692; https://doi.org/10.3390/ijms23147692 - 12 Jul 2022

Cited by 2 | Viewed by 1691

Abstract

Mandarin fish has an XX/XY sex-determination system. The female mandarin fish is typically larger than the male. Sex identification and the discovery of genes related to sex determination in mandarin fish have important theoretical significance in the elucidation of the regulation and evolutionary [...] Read more.

Mandarin fish has an XX/XY sex-determination system. The female mandarin fish is typically larger than the male. Sex identification and the discovery of genes related to sex determination in mandarin fish have important theoretical significance in the elucidation of the regulation and evolutionary mechanism of animal reproductive development. In this study, the chromosome-level genome of a female mandarin fish was assembled, and we found that LG24 of the genome was an X chromosome. A total of 61 genes on the X chromosome showed sex-biased expression. Only six gonadal genes (LG24G00426, LG24G003280, LG24G003300, LG24G003730, LG24G004200, and LG24G004770) were expressed in the testes, and the expression of the other gene LG24G003870 isoform 1 in the ovaries was significantly higher than that in the testes (p < 0.01). Five (except LG24G003280 and LG24G003300) of the seven aforementioned genes were expressed at the embryonic development stage, suggesting their involvement in early sex determination. The expression of LG24G004770 (encoding HS6ST 3-B-like) was also significantly higher in female muscles than in male muscles (p < 0.01), indicating other functions related to female growth. ZP3 encoded by LG24G003870 isoform 1 increased the C-terminal transmembrane domain, compared with that encoded by other fish zp3 isoforms, indicating their different functions in sex determination or differentiation. This study provides a foundation for the identification of sex-determining genes in mandarin fish. Full article

(This article belongs to the Special Issue Molecular Sexual Determination and Differentiation in Fishes)

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