Proteomic Analysis of Chinook Salmon (Oncorhynchus tshawytscha) Ovarian Fluid

Abstract

The ovarian, or coelomic, fluid that is released with the egg mass of many fishes is increasingly found to play an important role in several biological processes crucial for reproductive success. These include maintenance of oocyte fertility and developmental competence, prolonging of sperm motility, and enhancing sperm swimming speed. Here we examined if and how the proteome of chinook salmon (Oncorhynchus tshawytscha) ovarian fluid varied among females and then sought to examine the composition of this fluid. Ovarian fluid in chinook salmon was analyzed using 1D SDS PAGE and LC-MS/MS tryptic digest screened against Mascot and Sequest databases. We found marked differences in the number and concentrations of proteins in salmon ovarian fluid across different females. A total of 174 proteins were identified in ovarian fluid, 47 of which were represented by six or more peptides, belonging to one of six Gene Ontology pathways. The response to chemical stimulus and response to hypoxia pathways were best represented, accounting for 26 of the 174 proteins. The current data set provides a resource that furthers our understanding of those factors that influence successful egg production and fertilisation in salmonids and other species.

Sexual selection for genetic compatibility: the role of the major histocompatibility complex on cryptic female choice in Chinook salmon (Oncorhynchus tshawytscha)

“…The MHC allelic divergence at the whole exon and at the PBR as well as the number of shared alleles between mates did not explain a significant amount of the variation in sperm velocity. Thus, the observed mate compatibility, which explains roughly 44% of the variation in sperm velocity (42-45% across models), appears to be characterized by factors other than MHC, potentially by other peptides identified in the ovarian fluid of Chinook salmon (Johnson et al, 2014). MHC-dependent fertilization success was reported in mice (Wedekind et al, 1996;Rülicke et al, 1998) and the red jungle fowl (Løvlie et al, 2013), but the mechanisms by which such a non-random gamete fusion occurs are yet unknown.…”

Ovarian fluid impacts flagellar beating and biomechanical metrics of sperm between alternative reproductive tactics

“…6). This is particularly important for broadcast spawning teleost fishes, such as salmonids, as each female creates a unique spawning environment by simultaneously expelling ovarian fluid along with an egg batch (Lahnsteiner et al, 1995;Johnson et al, 2014).…”

“…ions, proteins as discussed below) of the activation media (see Wojtczak et al, 2007;Hatef et al, 2009;Rosengrave et al, 2009b, among others). The main protein composition of salmon ovarian fluid was investigated by Johnson et al (2014): their proteomic analysis led to identification of 174 proteins of interest, among which 26 are either involved in the hypoxia pathway or are chemical stimuli, some of the latter probably being related to control of sperm function near the egg.…”

Gamete-associated flavobacteria of the oviparous Chinook salmon (Oncorhynchus tshawytscha) in lakes Michigan and Huron, North America

“…Thus, this finding does not support the assumption that the presence of flavobacteria in the ovarian fluid is associated with their presence on eggs. However, the finding that the majority of the ovarian fluid-associated flavobacteria could also be recovered from eggs, albeit not from the same individuals, does suggest that the capability to colonize one may be associated with the capacity to colonize the other, which makes sense given the fact that unfertilized eggs are immersed in ovarian fluid in the gymnovarious Chinook salmon (Johnson et al, 2014). Also of interest was the finding that six of the ten flavobacterial taxa recovered from Chinook salmon were are also capable of generating systemic infections in spawning female Chinook salmon (Table 3), as evidenced by their presence in the kidney, spleen, and brain tissues.…”