title: Developmental effects of exposure to ultraviolet B radiation on the freshwater prawn Macrobrachium olfersi: Mitochondria as a target of environmental UVB radiation.
abstract: In South America, increased UVB radiation has become an important environmental issue that is potentially threatening aquatic ecosystems. Considering that species exhibit different degrees of sensitivity to UVB radiation and that embryos are more sensitive than organisms at later life stages, the aim of this study was to characterize the effects of UVB radiation on subcellular compartments of embryos of the freshwater prawn Macrobrachium olfersi. This species lives and reproduces in clear and shallow waters, where UV radiation can fully penetrates. Embryos were irradiated with a UVB 6W lamp for 30min and examined after 1h, 12h, 24h and 48h of exposure. The irradiance of the UVB used simulates the UV radiation that embryos receive in the natural environment. The subcellular compartment most affected by the UVB radiation was the mitochondria, which exhibited a circular shape, a decrease in mitochondrial cristae, rupture of membranes and a morphology compatible with fission. These impairments were observed simultaneously with increased ROS production, just after 1h of UVB exposure. Thus, we investigated proteins related to mitochondrial fission (Drp-1) and fusion (Mfn-1), which are essential to cell maintenance. We found a significant increase in Drp-1 expression at all analyzed time-points and a significant decrease in Mfn-1 expression only after 24h of UVB exposure. Additionally, a decrease in embryonic cell viability was verified via the mitochondrial integrity assay. To conclude, we observed important mitochondrial dysfunctions against the environmental stress caused by UVB radiation. Moreover, the cellular responses found are critical and should not be disregarded, because they impact embryos that can potentially compromise the aquatic ecosystems.
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil.
authors.forename: Thaline
authors.initials: T
authors.lastname: de Quadros
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil.
authors.forename: Heloísa
authors.initials: H
authors.lastname: Schramm
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil.
authors.forename: Eliane C
authors.initials: EC
authors.lastname: Zeni
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil.
authors.forename: Carmen
authors.initials: C
authors.lastname: Simioni
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: Silvana
authors.initials: S
authors.lastname: Allodi
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil.
authors.forename: Yara M R
authors.initials: YM
authors.lastname: Müller
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil; Centro Universitário Católica de Santa Catarina, Brazil.
authors.forename: Dib
authors.initials: D
authors.lastname: Ammar
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil.
authors.forename: Evelise M
authors.initials: EM
authors.lastname: Nazari
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D017753:Ecosystem; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000528:radiation effects; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water; D008928:Mitochondria / Q000528:radiation effects*; D063154:Mitochondrial Dynamics / Q000528:radiation effects; D008962:Models, Theoretical; D033541:Palaemonidae / Q000196:embryology / Q000254:growth & development / Q000528:radiation effects*; D013020:South America; D014466:Ultraviolet Rays
keywords: Cell viability; Crustacea; Embryo; Mitochondrial dynamics; UV radiation