The Role of Transcription Factors in Gonad Development and Sex Differentiation of a Teleost Model Fish—Guppy (Poecilia reticulata)

Abstract

The guppy (Poecilia reticulata) is one of the world’s most popular ornamental fish. Due to lecithotrophic viviparous, it is commonly used in toxicological studies and environmental monitoring. This study aimed to investigate the molecular mechanisms of gonad development and differentiation during guppy ontogenesis. The study mainly focused on the role and localization of potential specific sex markers and transcription factors: Sox9, Dmrt1, Erβ. For histological analysis, guppies of both sexes were collected at 1, 60, and 360 dph (day post-hatching). The gonads morphology and immunohistochemistry detection of mentioned markers localization were performed. The expression of Sox9 protein was compared between sexes. Histological analysis revelated all types of male germinal cells in 60 dph guppy’s testes. Maturated oocytes were visible in the ovaries of 360 dph fish. The Sox9 expression varied in spermatocytes and spermatids, from cellular to nuclear localization, and was higher in ovaries. Dmrt1 was detected in all testes groups and 360 dph ovaries. The Erβ was observed in both sexes at 60 and 360 dph. For the first time, the localization of transcription factors in guppy during ontogenesis was traced. The Sox9 designation as a factor regulating the development of germinal cells in adult guppies may facilitate the analysis of xenobiotics’ influence on fish’s reproductive system.

Effects of inbreeding and elevated rearing temperatures on strategic sperm production

“…In all models, brood identity was included as a random factor to account for measurements of several males from the same brood then assigned to different temperatures and social environments. Sperm production is strongly dependent on male size and age (Pitcher and Evans 2001; Gasparini et al 2010; Kamaszewski et al 2020), so their SL and adult age at testing were standardized (mean = 0, SD =1) and included as separate covariates in all analyses. Sperm data was power-transformed to fulfill the homogeneity of variances and the normality of residuals assumptions using Levene’s test and Shapiro-Wilks test, respectively.…”

Effects of inbreeding and elevated rearing temperatures on strategic sperm investment

“…In all models, brood identity was included as a random factor to account for measurements of several males from the same brood, then assigned to different temperatures and social environments. Sperm production is strongly dependent on male size and age ( Pitcher and Evans 2001 ; Gasparini et al 2010 ; Kamaszewski et al 2020 ), so their SL and adult age at testing were standardized (mean = 0, SD = 1) and included as separate covariates in all analyses. Sperm data was power-transformed to fulfill the homogeneity of variances and the normality of residual assumptions using Levene’s test and Shapiro-Wilks test, respectively.…”

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

“…To detect proliferating hepatocyte nuclei, the PCNA (proliferation cell nuclear antigen) monoclonal mouse antibody, clone PC10 (cat no. M0879; DAKO, Glostrup, Denmark) was used, according to the methodology described by Kamaszewski et al [ 51 ]. The following histomorphometric measurements (100 measurements from 1 individual) were taken in the liver on the HE-stained preparations: the area of the hepatocytes (µm 2 ), area of the hepatocyte nuclei (µm 2 ), and area of lipid vacuoles in hepatocytes (µm 2 ).…”