Post-testicular spermatozoa of a marine teleost can conduct cytoplasmic and mitochondrial translation.

Translational silence of spermatozoa has long been considered the norm in animals. However, studies in mammals have shown that the mitochondrial ribosomal machinery is selectively activated during capacitation in the female reproductive tract, while cytosolic ribosomes remain inactive. Here, using quantitative proteomics in a piscine model species, we show that proteins involved in mRNA processing and cytoplasmic translation are predominantly accumulated in immature spermatozoa within the extratesticular excurrent ducts, while those related to flagellar motility are enriched in ejaculated (mature) sperm.

Short-term polystyrene nanoplastic exposure alters zebrafish male and female germline and reproductive outcomes, unveiling pollutant-impacted molecular pathways.

Nanoplastics pollution is a rising environmental concern whose impacts on biodiversity and human health are far from being understood. This is particularly salient in aquatic ecosystems, where the majority of species depend on external fertilization for reproduction. Here we evaluated the effects of a short-term exposure to engineered polystyrene nanoplastics (NPs) in the zebrafish germline to further explore their impact on reproduction.

Aquaporin-3a Dysfunction Impairs Osmoadaptation in Post-Activated Marine Fish Spermatozoa.

Spermatozoon volume regulation is an essential determinant of male fertility competence in mammals and oviparous fishes. In mammals, aquaporin water channels (AQP3, -7 and -8) have been suggested to play a role in spermatozoon cell volume regulatory responses in the hypotonic female oviduct. In contrast, the ejaculated spermatozoa of marine teleosts, such as the gilthead seabream (), experience a high hypertonic shock in seawater, initially resulting in an Aqp1aa-mediated water efflux, cell shrinkage and the activation of motility.

Aqp4a and Trpv4 mediate regulatory cell volume increase for swimming maintenance of marine fish spermatozoa.

Volume regulation is essential for cell homeostasis and physiological function. Amongst the sensory molecules that have been associated with volume regulation is the transient receptor potential vanilloid 4 (TRPV4), which is a non-selective cation channel that in conjunction with aquaporins, typically controls regulatory volume decrease (RVD). Here we show that the interaction between orthologous AQP4 (Aqp4a) and TRPV4 (Trpv4) is important for regulatory volume increase (RVI) in post-activated marine fish spermatozoa under high osmotic stress.

Aquaporin splice variation differentially modulates channel function during marine teleost egg hydration.

Aquaporin-mediated oocyte hydration is a developmentally regulated adaptive mechanism that co-occurs with meiosis resumption in marine teleosts. It provides the early embryos with vital water until osmoregulatory systems develop, and in the majority of marine teleosts causes their eggs to float. Recent studies have shown that the subdomains of two water channels (Aqp1ab1 and Aqp1ab2) encoded in a teleost-specific aquaporin-1 cluster (TSA1C) co-evolved with duplicated Ywhaz-like (14-3-3ζ-like) binding proteins to differentially control their membrane trafficking for maximal egg hydration.