Light-specific wavelengths differentially affect the exploration rate, opercular beat, skin color change, opsin transcripts, and the oxi-redox system of the longsnout seahorse Hippocampus reidi

Autor(es)

Souto-Neto, Jose Araujo ; David, Daniela Dantas ; Zanetti, Giovanna ; Sua-Cespedes, Cristhian ; Freret-Meurer, Natalie Villar ; Moraes, Maria Nathalia ; de Assis, Leonardo Vinicius Monteiro ; Castrucci, Ana Maria de Lauro

• Tipo de documento: Artigo Científico
• Fonte: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY; v. 288, p. 20-pg., 2023-11-20.

Resumo

Light is a strong stimulus for the sensory and endocrine systems. The opsins constitute a large family of proteins that can respond to specific light wavelengths. Hippocampus reidi is a near-threatened seahorse that has a diverse color pattern and sexual dimorphism. Over the years, H. reidi's unique characteristics, coupled with its high demand and over-exploitation for the aquarium trade, have raised concerns about its conservation, primarily due to their significant impact on wild populations. Here, we characterized chromatophore types in juvenile and adult H. reidi in captivity, and the effects of specific light wavelengths with the same irradiance (1.20 mW/cm2) on color change, growth, and survival rate. The xanthophores and melanophores were the major components of H. reidi pigmentation with differences in density and distribution between life stages and sexes. In the eye and skin of juveniles, the yellow (585 nm) wavelength induced a substantial increase in melanin levels compared to the individuals kept under white light (WL), blue (442 nm), or red (650 nm) wavelengths. In addition, blue and yellow wavelengths led to a higher juvenile mortality rate in comparison to the other treatments. Adult seahorses showed a rhythmic color change over 24 h, the highest reflectance values were obtained in the light phase, representing a daytime skin lightening for individuals under WL, blue and yellow wavelength, with changes in the acrophase. The yellow wavelength was more effective on juvenile seahorse pigmentation, while the blue wavelength exerted a stronger effect on the regulation of adult physiological color change. Dramatic changes in the opsin mRNA levels were life stage-dependent, which may infer ontogenetic opsin functions throughout seahorses' development. Exposure to specific wavelengths differentially affected the opsins mRNA levels in the skin and eyes of juveniles. In the juveniles, skin transcripts of visual (rh1, rh2, and lws) and non-visual opsins (opn3 and opn4x) were higher in individuals under yellow light. While in the juvenile's eyes, only rh1 and rh2 had increased transcripts influenced by yellow light; the lws and opn3 mRNA levels were higher in juveniles' eyes under WL. Prolonged exposure to yellow wavelength stimulates a robust increase in the antioxidant enzymes sod1 and sod2 mRNA levels. Our findings indicate that changes in the visible light spectrum alter physiological processes at different stages of life in H. reidi and may serve as the basis for a broader discussion about the implications of artificial light for aquatic species in captivity. (AU)

• Processo FAPESP: 18/14728-0 - Melanopsina como fotorreceptor de UVA e sua relação com pigmentação, reparo de DNA, relógio biológico e componentes do eixo HPA: um novo alvo farmacológico?
• Beneficiário: Ana Maria de Lauro Castrucci
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 21/01659-2 - Participação da melanopsina na termorregulação de mamíferos
• Beneficiário: Giovanna Zanetti
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 17/24615-5 - Derrubando um paradigma? Melanopsina, um fotopigmento canônico, atuando como sensor para ajuste do relógio em órgãos não expostos à luz, e sua possível interação com canais TRP: estudo transdisciplinar envolvendo aspectos fisiológicos e patológicos
• Beneficiário: Ana Maria de Lauro Castrucci
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 17/26651-9 - Glaucoma como modelo de ruptura da informação temporal: impacto sobre o metabolismo
• Beneficiário: Maria Nathália de Carvalho Magalhães Moraes Figueira Borges
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 18/16511-8 - Participação dos sistemas de fotorrecepção e de controle temporal no desenvolvimento, progressão e metástase do melanoma maligno: investigação de novos alvos terapêuticos
• Beneficiário: Leonardo Vinícius Monteiro de Assis
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 18/23043-0 - Sistemas de foto- e termo-recepção no Siri-Azul Callinectes sapidus (Crustacea Brachyura) e a relação com o ciclo de muda
• Beneficiário: Daniela Dantas David
• Modalidade de apoio: Bolsas no Brasil - Doutorado