bims-sevkro 2018-08-05 papers

Gen Comp Endocrinol. 2018 Jul 25. pii: S0016-6480(17)30782-7. [Epub ahead of print]

Divergent evolution and clade-specific duplications of the Insulin-like Receptor in malacostracan crustaceans.

Herran Benjamin, Bertaux Joanne, Grève Pierre.

The Insulin-like Receptors (IRs) are an important protein family, represented by three members in vertebrates, two of which are well-known for their implication in metabolism (Insulin Receptor) and growth (IGF Receptor). In contrast, little is known about these receptors in invertebrates, in which a single gene generally exists except for a part of insects and other occasional species-specific duplications. In this study, we used publicly available sequences as well as de novo assembled transcriptomes to investigate the IR evolution in malacostracan crustaceans, animals in which the Insulin/IGF pathway is known to be implicated in sexual development through the androgenic gland hormone. We described the evolutionary divergence of malacostracan IRs compared to all the other metazoan sequences, including other pancrustaceans. We also demonstrated two well conserved duplications of IRs: one specific to the whole malacostracan class, another one specific to the decapod order. The potential implications for malacostracan biology are discussed.

Keywords: Crustaceans; Gene duplication; Insulin-like receptors; Phylogeny; Sexual differentiation

DOI: https://doi.org/10.1016/j.ygcen.2018.07.013

BMC Dev Biol. 2018 Jul 28. 18(1): 16

Effects of sex on response of the bovine preimplantation embryo to insulin-like growth factor 1, activin A, and WNT7A.

Paula Tríbulo, Gulnur Jumatayeva, Khoboso Lehloenya, James I Moss, Veronica M Negrón-Pérez, Peter J Hansen.

BACKGROUND: Alterations in maternal environment can sometimes affect embryonic development in a sexually-dimorphic manner. The objective was to determine whether preimplantation bovine embryos respond to three maternally-derived cell signaling molecules in a sex-dependent manner.RESULTS: Actions of three embryokines known to increase competence of bovine embryos to develop to the blastocyst stage, insulin-like growth factor 1 (IGF1), activin A, and WNT member 7A (WNT7A), were evaluated for actions on embryos produced in vitro with X- or Y- sorted semen from the same bull. Each embryokine was tested in embryos produced by in vitro fertilization of groups of oocytes with either pooled sperm from two bulls or with sperm from individual bulls. Embryos were treated with IGF1, activin A, or WNT7A on day 5 of culture. All three embryokines increased the proportion of cleaved zygotes that developed to the blastocyst stage and the effect was similar for female and male embryos. As an additional test of sexual dimorphism, effects of IGF1 on blastocyst expression of a total of 127 genes were determined by RT-qPCR using the Fluidigm Delta Gene assay. Expression of 18 genes was affected by sex, expression of 4 genes was affected by IGF1 and expression of 3 genes was affected by the IGF1 by sex interaction.
CONCLUSION: Sex did not alter how IGF1, activin A or WNT7A altered developmental competence to the blastocyst stage. Thus, sex-dependent differences in regulation of developmental competence of embryos by maternal regulatory signals is not a general phenomenon. The fact that sex altered how IGF1 regulates gene expression is indicative that there could be sexual dimorphism in embryokine regulation of some aspects of embryonic function other than developmental potential to become a blastocyst.

Keywords: Activin a; Embryo; Embryokine; Insulin-like growth factor 1; Sex-sorted semen; WNT7A

DOI: https://doi.org/10.1186/s12861-018-0176-2

Sci Total Environ. 2018 Jul 25. pii: S0048-9697(18)32657-3. [Epub ahead of print]646 245-256

Temporal evaluation of estrogenic endocrine disruption markers in smallmouth bass (Micropterus dolomieu) reveals seasonal variability in intersex.

Luke R Iwanowicz, A E Pinkney, C P Guy, A M Major, K Munney, V S Blazer, D A Alvarez, H L Walsh, A Sperry, R Braham, L R Sanders, D R Smith.

A reconnaissance project completed in 2009 identified intersex and elevated plasma vitellogenin in male smallmouth bass inhabiting the Missisquoi River, VT. In an attempt to identify the presence and seasonality of putative endocrine disrupting chemicals or other factors associated with these observations, a comprehensive reevaluation was conducted between September 2012 and June 2014. Here, we collected smallmouth bass from three physically partitioned reaches along the river to measure biomarkers of estrogenic endocrine disruption in smallmouth bass. In addition, polar organic chemical integrative samples (POCIS) were deployed to identify specific chemicals associated with biological observations. We did not observe biological differences across reaches indicating the absence of clear point source contributions to the observation of intersex. Interestingly, intersex prevalence and severity decreased in a stepwise manner over the timespan of the project. Intersex decreased from 92.8% to 28.1%. The only significant predictor of intersex prevalence was year of capture, based on logistic regression analysis. The mixed model of fish length and year-of-capture best predicted intersex severity. Intersex severity was also significantly different across late summer and early spring collections indicating seasonal changes in this metric. Plasma vitellogenin and liver vitellogenin Aa transcript abundance in males did not indicate exposure to estrogenic endocrine disrupting chemicals at any of the four sample collections. Analysis of chemicals captured by the POCIS as well as results of screening discrete water samples or POCIS extracts did not indicate the contribution of appreciable estrogenic chemicals. It is possible that unreported changes in land-use activity have ameliorated the problem, and our observations indicate recovery. Regardless, this work clearly emphasizes that single, snap shot sampling for intersex may not yield representative data given that the manifestation of this condition within a population can change dramatically over time.

Keywords: Endocrine disruption; Fish; Intersex; National Wildlife; POCIS; Refuge

DOI: https://doi.org/10.1016/j.scitotenv.2018.07.167