Morphological and Biochemical Alterations of Abalone Testicular Germ Cells and Spawned Sperm and their Fertilizing Ability

Abstract

In this study, we aimed to detect morphological and biochemical changes in developing germ cells (Gc), testicular sperm (Tsp), and spawned sperm (Ssp) using capacitation-associated characteristics. Gradual changes in the profiles of two membrane proteins, namely NaCl- and detergent-extractable proteins, were observed as compared Gc with Tsp and Tsp with Ssp. These membrane modifications were accomplished mostly through the introduction of new protein sets, both peripheral and integral, into Tsp and Ssp membranes. Activation of serine proteases, particularly in Ssp detergent-extracted proteins with the molecular masses of 38-130 kDa was evident and marked a major difference between Ssp and Tsp. An increase in the level of tyrosine phosphorylation of the proteins ranging from 15 to 20 kDa was noted in Tsp and remained constant in Ssp. Specifically, these three capacitation-associated characteristics could be detected in Ssp, possessing full fertilizing capacity. The lack of an activated proteolytic activity in Tsp resulted in a delayed fertilization, but not affected fertilizing ability. We believe that these characteristics should be advantageous in predicting abalone sperm fertilizing capability, particularly in cases when isolated germ cells or purified Tsp are used in place of spawned sperm in abalone aquaculture.

Cathepsin D in prawn reproductive system: its localization and function in actin degradation

“…In crustaceans and other aquatic animals, the existence and properties of many enzymes in digestive and immune systems have been gradually accumulated ( Garcia-Carreño, Navarrete del Toro & Muhlia-Almazan, 2014 ; Bañuelos Vargas et al., 2018 ). In the reproductive system, presence of a trypsin-like protease as sperm surface enzymes and its activation in association with post-testicular sperm modifications prior to gamete interaction have been reported in shrimp and prawn species ( Suphamungmee et al, 2008 ; Watthammawut et al, 2015 ). Here, we further characterized the other type of sperm surface enzyme, cathepsin-D (CAT-D), and demonstrated its role in actin filament hydrolysis.…”

Changes of fatty acids in phosphatidylcholine on sperm membrane during Macrobrachium rosenbergii sperm transit through spermatic duct and lipid analysis in spermatic vesicles

“…In some species of marine invertebrates, it is originally believed that the sperm simultaneously acquire fertilizing ability immediately after their production following a "broadcast" sprawning from the testis (Ohlendieck and Lennarz, 1996;Vacquier, 1998). However, the recent evidence in the broadcast spawning animals, for instance, abalones and Penaeus monodon, addresses the essence of sperm modification post-testicularly in order for them to gain fertilizing capability (Alfaro et al, 2003, Vanichviriyakit et al, 2004Suphamungmee et al, 2008). In Macrobrachium rosenbergii and some other crustaceans, some differences in reproductive biology should also be noted.…”

Supplemental Information 1: Full sequence of MrCAT-D and amino acid positions of designed primers

“…In crustaceans and other aquatic animals, the existence and properties of many enzymes in digestive and immune systems have been gradually accumulated (Garcia-Carreño, Navarrete del Toro & Muhlia-Almazan, 2014;Bañuelos Vargas et al, 2018). In the reproductive system, presence of a trypsin-like protease as sperm surface enzymes and its activation in association with post-testicular sperm modifications prior to gamete interaction have been reported in shrimp and prawn species (Suphamungmee et al, 2008;Watthammawut et al, 2015). Here, we further characterized the other type of sperm surface enzyme, cathepsin-D (CAT-D), and demonstrated its role in actin filament hydrolysis.…”