Opposing roles for Bmp signalling during the development of electrosensory lateral line organs.

The lateral line system enables fishes and aquatic-stage amphibians to detect local water movement via mechanosensory hair cells in neuromasts, and many species to detect weak electric fields via electroreceptors (modified hair cells) in ampullary organs. Both neuromasts and ampullary organs develop from lateral line placodes, but the molecular mechanisms underpinning ampullary organ formation are understudied relative to neuromasts. This is because the ancestral lineages of zebrafish (teleosts) and (frogs) independently lost electroreception.

Characterization of regeneration initiating cells during Xenopus laevis tail regeneration.

Background: Embryos are regeneration and wound healing masters. They rapidly close wounds and scarlessly remodel and regenerate injured tissue. Regeneration has been extensively studied in many animal models using new tools such as single-cell analysis.

Secondary growth ovarian follicles of the pigmented sterlet sturgeon Acipenser ruthenus L. 1758 (Acipenseriformes, Chondrostei, Actinopterygii, Osteichthyes) - Microscopic study of oocytes, egg envelope and diversification of follicular cells.

The individual ovarian follicle of sturgeons (Acipenseriformes, Acipenseridae) contains an oocyte surrounded by follicular cells (FCs), basal lamina, and thecal cells. The late stages of the secondary growth of follicles (mid- and advanced vitellogenic) are not fully explained in Acipenseriformes. To explore and discuss the ultrastructure of oocytes, FCs, an egg envelope, and explain how micropylar cells differentiate and the canals of a multiple micropyle are formed, the samples of ovaries of the mature sterlet sturgeon Acipenser ruthenus were examined.

Species-specific differences in DNA damage sensitivity at early developmental stage: A comparative study of sterlet (Acipenser ruthenus) and common carp (Cyprinus carpio).

DNA damage in embryos shapes the development of an organism. Understanding life stage-specific differences between fish species is essential for ecological risk assessment measures. We explored DNA damage sensitivity in two nonmodel fish species, sterlet (Acipenser ruthenus) and common carp (Cyprinus carpio).

Sturgeon gut development: a unique yolk utilization strategy among vertebrates.

In vertebrates, maternally supplied yolk is typically used in one of two ways: either intracellularly by endodermal cells or extracellularly via the yolk sac. This study delves into the distinctive gut development in sturgeons, which are among the most ancient extant fish groups, contrasting it with that of other vertebrates. Our observations indicate that while sturgeon endodermal cells form the archenteron (i.

Characterization of potential spermatogonia biomarker genes in the European eel (Anguilla anguilla).

Identification of specific molecular markers for spermatogonial stem cells in teleost is crucial for enhancing the efficacy of reproductive biotechnologies in aquaculture, such as transplantation and surrogate production in fishes. Since it is not yet possible to distinguish spermatogonial stem cells of European eel (Anguilla anguilla) using specific molecular markers, we isolated spermatogonial cells from immature European eels to find these potential markers. We attempted this by studying three candidate genes: vasa, nanos2, and dnd1.

Identification of multiple transcription factor genes potentially involved in the development of electrosensory mechanosensory lateral line organs.

In electroreceptive jawed vertebrates, embryonic lateral line placodes give rise to electrosensory ampullary organs as well as mechanosensory neuromasts. Previous reports of shared gene expression suggest that conserved mechanisms underlie electroreceptor and mechanosensory hair cell development and that electroreceptors evolved as a transcriptionally related "sister cell type" to hair cells. We previously identified only one transcription factor gene, , as ampullary organ-restricted in the developing lateral line system of a chondrostean ray-finned fish, the Mississippi paddlefish ().

Genome-wide comparative methylation analysis reveals the fate of germ stem cells after surrogate production in teleost.

Background: Surrogate production by germline stem cell transplantation is a powerful method to produce donor-derived gametes via a host, a practice known as surrogacy. The gametes produced by surrogates are often analysed on the basis of their morphology and species-specific genotyping, which enables conclusion to be drawn about the donor's characteristics. However, in-depth information, such as data on epigenetic changes, is rarely acquired.

Asymmetry in previtellogenic and early vitellogenic oocytes, ultrastructure of follicular cells and egg envelope in the pigmented sterlet, Acipenser ruthenus L. 1758 (Chondrostei, Acipenseriformes).

Ovarian follicles of sterlets (Acipenser ruthenus) are composed of a single oocyte surrounded by follicular cells (FCs), basal lamina, and thecal cells. Previtellogenic oocytes are polarized. Homogeneous ooplasm (contains ribosomes) and granular ooplasm (comprises nuage aggregations of nuclear origin, rough endoplasmic reticulum (RER), Golgi complexes, ribosomes, and mitochondria) are distinguished.

Enhancement of zebrafish sperm production via a large body-sized surrogate with germ cell transplantation.

Zebrafish (Danio rerio) is a commonly-used vertebrate model species for many research areas. However, its low milt volume limits effective cryopreservation of sperm from a single individual and often precludes dividing a single semen sample to conduct multiple downstream procedures such as genomic DNA/RNA extraction and in-vitro fertilization. Here, we apply germ stem cell transplantation to increase zebrafish sperm production in a closely related larger species from the same subfamily, giant danio Devario aequipinnatus.

DNA repair genes play a variety of roles in the development of fish embryos.

Embryogenesis is one of the most important life stages because it determines an organism's healthy growth. However, embryos of externally fertilizing species, such as most fish, are directly exposed to the environment during development and may be threatened by DNA damaging factors (pollutants, UV, reactive oxygen species). To counteract the negative effects of DNA fragmentation, fish embryos evolved complex damage response pathways.

Does dietary exposure to 17α-ethinylestradiol alter biomarkers related with endocrine disruption and oxidative stress in the adult triploid of Danio rerio?

This study was conducted to investigate a comprehensive effect of 17α-ethinylestradiol (EE2) in zebrafish (Danio rerio) with the emphasis on endocrine disruption, oxidative stress and detoxification processes at different levels. Adult male triploid zebrafish were exposed to EE2 administered in feed at two concentrations - 10 and 1000 μg/kg for six weeks. The estrogenic potential of EE2 was evaluated using an analysis of vitellogenin, gene expression focused on reproductive disorders and gonad histological examination.

Intracytoplasmic sperm injection in sturgeon species: A promising reproductive technology of selected genitors.

Sturgeons are the most endangered species group and their wild populations continue to decrease. In this study, we apply intracytoplasmic sperm injection (ICSI), an assisted reproductive technology, for the first time in endangered and critically endangered sturgeons. Using various egg-sperm species combinations we performed different ICSI experiments with immobilized pre- or non-activated spermatozoa, single or many, fresh or cryopreserved.

Use of all-male triploid population of zebrafish (Danio rerio) for evaluation of 17α-ethinylestradiol effects.

Objectives: We tested the toxicity of ethinylestradiol, a semisynthetic estrogen used in oral contraceptives, on all-male triploid zebrafish using commercial feeds and three different doses concentrations. We aimed to determine whether ethinylestradiol peroral administration resulted in vitellogenin production and whether all-male triploid zebrafish could serve as a model species for xenoestrogen testing.

Methods: The actual concentrations of 17α-ethinylestradiol were 0.

Vitrification of the ovarian tissue in sturgeons.

The aim of this study was to test whether vitrification of sterlet Acipenser ruthenus and Russian sturgeon Acipenser gueldenstaedtii ovarian tissue through needle-immersed vitrification (NIV) is an efficient strategy for the preservation of oogonia (OOG) in order to supplement the current conservation efforts for these endangered fish species. Histological analyses of the gonads displayed that the ovaries of both species were immature and contained predominantly OOG and primary oocytes. The germline origin of these cells was verified by localization of the vasa protein through immunocytochemistry.

Optimization of culture conditions of common carp germ cells for purpose of surrogate production.

Common carp () is the fourth most-produced fish species in aquaculture and frequently used model species with significant effort invested in development of biotechnological applications. In present study, we attempted to establish an germ cell culture condition for short term cell culture, which could facilitate further applications such as surrogacy or gene manipulation. Basal media and different types of feeder cells were investigated to optimize carp germ cell culture condition to favor maintenance of mitotic proliferation.

Comparison of RNA localization during oogenesis within and .

The oocyte is a unique cell, from which develops a complex organism comprising of germ layers, tissues and organs. In some vertebrate species it is known that the asymmetrical localization of biomolecules within the oocyte is what drives the spatial differentiation of the daughter cells required for embryogenesis. This asymmetry is first established to produce an animal-vegetal (A-V) axis which reflects the future specification of the ectoderm, mesoderm, and endoderm layers.

Evolutionary conservation of maternal RNA localization in fishes and amphibians revealed by TOMO-Seq.

Asymmetrical localization of biomolecules inside the egg, results in uneven cell division and establishment of many biological processes, cell types and the body plan. However, our knowledge about evolutionary conservation of localized transcripts is still limited to a few models. Our goal was to compare localization profiles along the animal-vegetal axis of mature eggs from four vertebrate models, two amphibians (Xenopus laevis, Ambystoma mexicanum) and two fishes (Acipenser ruthenus, Danio rerio) using the spatial expression method called TOMO-Seq.

Transcriptome and Proteome Analyses Reveal Stage-Specific DNA Damage Response in Embryos of Sturgeon ().

DNA damage during early life stages may have a negative effect on embryo development, inducing mortality and malformations that have long-lasting effects during adult life. Therefore, in the current study, we analyzed the effect of DNA damage induced by genotoxicants (camptothecin (CPT) and olaparib) at different stages of embryo development. The survival, DNA fragmentation, transcriptome, and proteome of the endangered sturgeon were analyzed.

Partial Gene Knockout Diverts LC-PUFA Biosynthesis via an Alternative Δ8 Pathway with an Impact on the Reproduction of Female Zebrafish ().

The zebrafish () genome contains a single gene encoding a desaturase (FADS2) with both Δ6 and Δ5 activities, the key player in the endogenous biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs), which serve essential functions as membrane components, sources of energy and signaling molecules. LC-PUFAs include the precursors of eicosanoids and are thus predicted to be indispensable molecules for reproductive health in virtually all vertebrates. In mice, an amniotic vertebrate, deletion mutants, both males and females, have been confirmed to be sterile.

Clonal gametogenesis is triggered by intrinsic stimuli in the hybrid's germ cells but is dependent on sex differentiation†.

Interspecific hybridization may trigger the transition from sexual reproduction to asexuality, but mechanistic reasons for such a change in a hybrid's reproduction are poorly understood. Gametogenesis of many asexual hybrids involves a stage of premeiotic endoreplication (PMER), when gonial cells duplicate chromosomes and subsequent meiotic divisions involve bivalents between identical copies, leading to production of clonal gametes. Here, we investigated the triggers of PMER and whether its induction is linked to intrinsic stimuli within a hybrid's gonial cells or whether it is regulated by the surrounding gonadal tissue.

Efficient CRISPR Mutagenesis in Sturgeon Demonstrates Its Utility in Large, Slow-Maturing Vertebrates.

In the last decade, the CRISPR/Cas9 bacterial virus defense system has been adapted as a user-friendly, efficient, and precise method for targeted mutagenesis in eukaryotes. Though CRISPR/Cas9 has proven effective in a diverse range of organisms, it is still most often used to create mutant lines in lab-reared genetic model systems. However, one major advantage of CRISPR/Cas9 mutagenesis over previous gene targeting approaches is that its high efficiency allows the immediate generation of near-null mosaic mutants.

Isolation and Characterization of Highly Pure Type A Spermatogonia From Sterlet () Using Flow-Cytometric Cell Sorting.

Sturgeons are among the most ancient linages of actinopterygians. At present, many sturgeon species are critically endangered. Surrogate production could be used as an affordable and a time-efficient method for endangered sturgeons.

The remarkable dynamics in the establishment, rearrangement, and loss of dentition during the ontogeny of the sterlet sturgeon.

Background: Sturgeons belong to an early-branching lineage often used as a proxy of ancestor-like traits of ray-finned fishes. However, many features of this lineage, such as the transitory presence and the eventual loss of dentition, exemplify specializations that, in fact, provide important information on lineage-specific evolutionary dynamics.

Results: Here, we introduce a detailed overview of the dentition during the development of the sterlet sturgeon.