Project description:Sturgeons, producers of black caviar, are one of the most valuable wildlife commodities on earth (Pikitch et al., 2005). They appeared approximately 200 million years ago, and are known as living fossils (Bemis et al., 1997). Sturgeon populations dramatically declined as a result of overfishing, poaching and habitat destruction (Birstein, 1993; Billard and Lecointre, 2001; Vidotto et al., 2013). International Union for Conservation of Nature and Natural Resources (IUCN) classified over 85% of sturgeon species as at risk of extinction, more than any other group of species. Therefore, artificial reproduction techniques have been developed for sturgeons to meet the demands of aquaculture and restocking programs. Basic knowledge regarding biology of reproduction such as egg activation and fertilization can help improving the efficiency of artificial reproduction. Fertilization happens when gametes, spermatozoon and egg, are fused together. Egg activation refers to a series of morphological and molecular changes that occur in the egg during and after fertilization. Egg activation is believed to prevent polyspermy, and may also establish a micro-environment to support embryo development (Wong and Wessel, 2006; Niksirat et al., 2015a). Although, earlier researchers have illustrated egg structure and its morphological changes during egg fertilization and activation in sturgeons (Cherr and Clark, 1982, 1985a; Linhart and Kudo, 1997; Debus et al., 2008; Zelazowska, 2010), there is still a lack of molecular knowledge to improve our understanding of this stage of reproduction in these animals. Eggs of sturgeon are released to aqueous environment, where they are fertilized, activated and develop an adhesive layer after contact with freshwater (Cherr and Clark, 1984; Vorobeva and Markov, 1999). Although, egg stickiness is necessary for eggs in nature to help them find a stable position by attaching to substrates such as gravel and stone and increase chance of survival until hatching (Riehl and Patzner, 1998), but can cause high rate of mortality during artificial incubation as a result of attachment of eggs together and subsequent suffocation in limited space of incubators. Using clay suspension in water as an activation medium has been proven to be effective to block egg stickiness in sturgeon eggs (Dettlaff et al., 1993). In recent years, label-free protein quantification techniques have been developed based on the presumption of linear proportionality between peptide mass peak signal intensity and concentration of a given peptide. This approach avoids the limitations and multiple preparation steps of methods such as those based on two-dimensional gel electrophoresis (Niksirat et al., 2015b). The aim of present study was to identify and quantify proteome changes of sterlet eggs during activation in different activation media, water and clay suspension, using label-free protein quantification technique.
Project description:In this study we analyzed the spatial and temporal localization of maternal transcripts during oogenesis in Acipenser ruthenus. The occurrence of transcript asymmetry in A. ruthenus has been described at a global level only in matured eggs. However not much is known about the asymmetry during oogenesis. In this study we assessed the temporal establishment of the transcript localization at a global level for A. ruthenus. We were able to determine that there are many transcripts that show temporal variability in the establishment of their localization. We observed an early, predefined and also late pathways for both the vegetally and animally localized transcripts. Additionally, we showed that some maternal transcripts are dynamic during oogenesis with degradation and de novo production being observed. Our study showed that in additional to spatial orientation to the transcripts, there is a strong temporal factor. The discovery of these new temporal profiles should help to better understand the driving forces during embryogenesis.
Project description:Transferrins are a superfamily of iron-binding proteins and are recognized as multifunctional proteins. In the present study, transcriptomic and proteomic methods were used to identify transferrins in the reproductive organs and sperm of out-of-spawning and spermiating sterlet (Acipenser ruthenus) males. The results showed that seven transferrin transcripts were identified in the transcriptome of sterlet, and these transcripts were qualified as two different transferrin genes, serotransferrin and melanotransferrin, with several isoforms present for serotransferrin. The relative abundance of serotransferrin isoforms was higher in the kidneys and Wolffian ducts in the spermiating males compared to out-of-spawning males. In addition, transferrin was immunodetected in sterlet seminal plasma, but not in sterlet spermatozoa extract. Mass spectrometry identification of transferrin in seminal plasma but not in spermatozoa corroborates immunodetection. The identification of transferrin in the reproductive organs and seminal plasma of sterlet in this study provides the potential function of transferrin during sturgeon male reproduction.