Single cones give rise to multi-cone types in the retinas of fishes

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: March 6, 2025

Retinal cone photoreceptors are specialized neurons that capture light to begin the process of daylight vision. They occur as individual cells (i.e., single cones), or combinations structurally linked cells, such double and triple cones found in retinas non-eutherian vertebrates. These different morphological types form mosaics varying regularity, with patterned nearly perfect lattices many bony fishes (teleosts) some geckos. Although were first reported over 150 years ago, how they whether from coalescing cones, progenitors) remains uncertain. In turn, there is a general vertebrate sequence appearance unknown. Here, developing seven species teleosts examined revealing only arranged hexagonal-like mosaics, present at earliest stages photoreceptor differentiation. Double arose formation multi-cone type (such square mosaic, where each surrounded by four cones) followed dynamics depending on was altricial precocial. Single therefore primordial which all preceded other mosaic patterns. Based observations transitional retinas, we propose model for transformation hexagonal square. The those land vertebrates constitute an example convergent evolution achieve elliptical waveguide structure, likely improved spatio-temporal resolution.

Language: Английский

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Damsels in Disguise: Development of Ultraviolet Sensitivity and Colour Patterns in Damselfishes (Pomacentridae)

Molecular Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

ABSTRACT Damselfishes (Pomacentridae) are widespread and highly abundant on tropical coral reefs. They exhibit diverse body colouration within between the ~250 species across ontogenetic stages. In addition to human‐visible colours (i.e., 400–700 nm), most adult damselfishes reflect ultraviolet (UV, 300–400 nm) colour patches. UV sensitivity signals essential for feeding form basis a secret communication channel invisible many UV‐blind predatory fish reef; however, how these traits develop stages their distribution damselfish family is poorly characterised. Here, we used photography, phylogenetic reconstructions of opsin genes, differential gene expression analysis (DGE) retinal samples investigate development vision patterns in three (pre‐settlement larval, juvenile, adult) 11 species. Using DGE, found similar juveniles adults, which strongly differed from larvae. All all expressed at least one UV‐sensitive sws1 gene. However, only started appear juvenile stage. Moreover, Pomacentrus displayed complex that were correlated with two copies. This could mean some can discriminate change component. We demonstrate dramatic shifts both while highlighting importance considering ontogeny when studying coevolution visual systems signals.

Language: Английский

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Horizontal cell connectivity in the anchovy retina—a 3D electron microscopic study

BMC Biology, Journal Year: 2025, Volume and Issue: 23(1)

Published: May 19, 2025

Abstract Background Block-face scanning electron microscopy has opened a new era of connectomics research, in which it is possible to make dense reconstructions all cells clipping neuronal network, such as the retina, resolving synaptic contacts. Anchovies, exceptionally abundant marine teleosts, have retinae with regions for triple cone-based color vision and region specialized cone photoreceptors, so-called polycones, made long short cones axially oriented outer segment lamellae polarization contrast vision. This modality, discovered 1970s, unique vertebrates, but neural wiring generation deeper retinal layers unknown so far. Results To elucidate European anchovy Engraulis encrasicolus (Linnaeus, 1758), first project, we investigated shapes cone-specific rules 3 horizontal cell types using volume subsequent computer-aided reconstruction: H1 contact both polycone, H2 only cones, H3 are exclusively connected rods. In addition, distinctive double band Müller fibers layer axon terminals were structurally clarified. Conclusions The findings suggest that (1) monochromatic system based on fine structure specializations retina an inherited (bichromatic) mechanism inner (2) polycones arose from red (now long) green short) (3) blue single disappeared relevant region.

Language: Английский

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Light environment and seasonal variation in the visual system of the red shiner (Cyprinella lutrensis)

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: May 5, 2024

Abstract The light environment underwater can vary dramatically over space and time, challenging the visual systems of aquatic organisms. To meet these challenges, many species shift their spectral sensitivities through changes in pigment chromophore opsin expression. red shiner ( Cyprinella lutrensis ) is a cyprinid minnow that has rapidly expanded its range throughout North America inhabits wide habitats. We hypothesized system plasticity contributed to shiner’s success. investigated usage expression by collecting shiners from three Oklahoma creeks turbidity year. characterized spectroradiometry, measured composition eyes with high performance liquid chromatography, CYP27C1 enzyme function heterologous expression, examined ocular gene RNA sequencing de novo transcriptome assembly. observed significantly higher proportions long- wavelength shifted A 2 fish turbid site samples collected winter, suggesting there may be temperature-dependent trade-off between chromophore-based tuning chromophore-related noise. Opsin varied clear creeks, but did not align as expected, magnitude differences was limited compared composition. confirmed catalyzes conversion 1 , well correlated levels eye, occurring outside eye.

Language: Английский

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Pigment Identification and Gene Expression Analysis during Erythrophore Development in Spotted Scat (Scatophagus argus) Larvae

International Journal of Molecular Sciences, Journal Year: 2023, Volume and Issue: 24(20), P. 15356 - 15356

Published: Oct. 19, 2023

Red coloration is considered an economically important trait in some fish species, including spotted scat, a marine aquaculture fish. Erythrophores are gradually covered by melanophores from the embryonic stage. Despite studies of black spot formation and melanophore little known about erythrophore development, which responsible for red coloration. 1-phenyl 2-thiourea (PTU) tyrosinase inhibitor commonly used to inhibit melanogenesis contribute visualization development. In this study, scat embryos were treated with 0.003% PTU 0 72 h post fertilization (hpf) melanin. clearly observed during stage 14 hpf, showing initial increase (14 36 hpf), followed gradual decrease (36 hpf). The number size erythrophores at hpf larger than those 24 hpf. At LC-MS absorbance spectrophotometry revealed that carotenoid content was eight times higher pteridine content, β-carotene lutein main pigments related larvae. Compared their expression normal hatching group, rlbp1b, rbp1.1, rpe65a retinol metabolism soat2 apoa1 steroid hormone biosynthesis significantly up-regulated rh2 associated phototransduction down-regulated. By qRT-PCR, levels genes involved (scarb1, plin6, plin2, apoda, bco1, rep65a), synthesis (gch2), chromatophore differentiation (slc2a15b csf1ra) except bco1. These gene profiles consistent developmental changes erythrophores. findings provide insights into pigment cell function regulation selective breeding programs ornamental aquatic animals.

Language: Английский

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Systematic analysis of ocular features and responses of cultured spotted wolffish (Anarhichas minor)

Journal of Fish Diseases, Journal Year: 2024, Volume and Issue: 47(8)

Published: May 6, 2024

Abstract A better understanding of unique anatomical and functional features the visual systems teleost fish could provide key knowledge on how these influence health survival animals in both wild culture environments. We took a systematic approach to assess some spotted wolffish ( Anarhichas minor ), species increasing importance North Atlantic aquaculture initiatives. The lumpfish Cyclopterus lumpus ) was included studies comparative manner reference. Histology, light electron microscopy were used study spatial distribution occurrence cone photoreceptor cells nature retinal tissues, while immunohistochemistry explore expression patterns two markers, XAP‐1 XAP‐2, species. marine bacterial infection paradigm host–pathogen responses might impact markers animals. define basic mosaic present an ultrastructural macroscopic geographical configuration pigment tissues Photoreceptor XAP‐2 have novel retinas, exogenous pathogenic influences can affect normal pattern lumpfish. Live tank‐side ophthalmoscopy spectral domain optical coherence tomography (SD‐OCT) revealed that cultured display variations shape tissue. These complementary imaging findings suggest harbour ocular not yet described teleosts function involve specific tissue dynamics Finally, extensive endogenous biofluorescence is animals, which raises questions about use ways for perception and/or communication. This work advances fundamental economically important but now threatened provides foundation further research versus disease settings. also be useful optimizing welfare towards one or integrative perspective.

Language: Английский

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Damsels in a hidden colour: development of ultraviolet sensitivity and colour patterns in damselfishes (Pomacentridae)

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 23, 2024

Damselfishes (Pomacentridae) are widespread and highly abundant on tropical coral reefs. They exhibit diverse body colouration within between the ~250 species across ontogenetic stages. In addition to human visible colours (i.e., 400-700 nm), most adult damselfishes reflect ultraviolet (UV, 300-400 nm) colour patches. UV sensitivity signals essential for feeding form basis a secret communication channel invisible many UV-blind predatory fish reef; however, how these traits develop stages, their distribution damselfish family is poorly characterised. Here, we used photography, phylogenetic reconstructions of opsin genes, differential gene expression analysis (DGE) retinal samples, investigate development vision patterns in three stages (pre-settlement larval, juvenile, adult) eleven species. Using DGE, found similar juveniles adults, which strongly differed from larvae. All all expressed at least one UV-sensitive sws1 gene. However, only started appear juvenile stage. Moreover, Pomacentrus displayed complex that were correlated with two copies. This could mean some can discriminate change component. We demonstrate dramatic shifts both damselfish, while highlighting importance considering ontogeny when studying coevolution visual systems signals.

Language: Английский

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Deep-sea fish reveal alternative pathway for vertebrate visual development

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 10, 2024

Abstract Vertebrate vision is accomplished by two phenotypically distinct types of photoreceptors in the retina: saturation-resistant cones for detection bright light and highly sensitive rods dim conditions [1]. The current dogma that, during development, all vertebrates initially feature a cone-dominated retina, are added later [2, 3]. By studying ontogeny three species deep-sea fishes, we show that their larvae express cone-specific genes with rod-like morphologies. Through these fishes either retain this cone retina ( Maurolicus mucronatus ) or switch to true rod expression rod-specific transcription factors Vinciguerria mabahiss Benthosema pterotum ). In contrast most marine which inhabit upper layer open ocean, occur deeper, exposing them dimmer environment [4–7]. Spectral maxima predictions from molecular dynamics simulations environmental estimations suggest using transmuted combine characteristics both maximises visual performance conditions. Our findings provide molecular, morphological, functional evidence evolution an alternative developmental pathway vertebrate vision.

Language: Английский

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Damsels in a Hidden Colour: Development of Ultraviolet Sensitivity and Colour Patterns in Damselfishes (Pomacentridae)

Published: Oct. 8, 2024

Damselfishes (Pomacentridae) are widespread and highly abundant on tropical coral reefs. They exhibit diverse body colouration within between the ∼250 species across ontogenetic stages. In addition to human visible colours (i.e., 400-700 nm), most adult damselfishes reflect ultraviolet (UV, 300-400 nm) colour patches. UV sensitivity signals essential for feeding form basis a secret communication channel invisible many UV-blind predatory fish reef; however, how these traits develop stages, their distribution damselfish family is poorly characterised. Here, we used photography, phylogenetic reconstructions of opsin genes, differential gene expression analysis (DGE) retinal samples, investigate development vision patterns in three stages (pre-settlement larval, juvenile, adult) eleven species. Using DGE, found similar juveniles adults, which strongly differed from larvae. All all expressed at least one UV-sensitive _sws1_ gene. However, only started appear juvenile stage. Moreover, _Pomacentrus_ displayed complex that were correlated with two copies. This could mean some can discriminate change component. We demonstrate dramatic shifts both damselfish, while highlighting importance considering ontogeny when studying coevolution visual systems signals.

Language: Английский

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Transcriptome analysis reveals the importance of phototransduction during the first-feeding in mandarin fish (Siniperca chuatsi)

Functional & Integrative Genomics, Journal Year: 2024, Volume and Issue: 24(6)

Published: Oct. 25, 2024

Language: Английский

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