Proteomic profile of seminal plasma from Pêga donkeys (Equus asinus) with high sperm motility and vigor: Implications for assisted reproduction.

Donkeys of the Pêga breed (Equus asinus) have been used for two centuries to produce breeding stock and create hybrids for labor and transport in southeast Brazil, and for exporting meat and milk to other countries. Furthermore, they are used in competitions, as they are docile and easy to handle. However, assisted reproduction success rates for frozen donkey semen are remarkably low, with no standardized method for cryopreserving sperm after removal of seminal plasma. This work aims to reveal the biological involvement of seminal plasma proteins from Pêga donkeys in aiding the development of assisted reproduction. This study was carried out with 14 ejaculates collected every eight days, throughout the breeding season, from three healthy fertile Pêga donkeys, with an average age of four years. After confirming the high freezability of fresh semen by evaluating quality parameters, the seminal plasma was separated by centrifugation and an aliquot from each collection was microfiltered and frozen. A label-free technique followed by LC-MS/MS analysis applied to pools of seminal plasma samples from each animal revealed 522 proteins in the proteomic profile, of which 49.8 % (260 proteins) are related to cellular energy transformation, and many proteins involved in reproduction (76), spermatogenesis (38), fertilization (29), among other biological process. By comparison with literature, Pêga donkeys share many proteins with donkeys of Dezhou breed that present great potential as fertility biomarkers. Our results showed proteins positively related to fertilization for different breeds of donkeys around the world, helping to enhance the assisted reproduction of Pêga donkeys.

Proteoforms of ß-Casein, α-s1-Casein, α-Lactalbumin, Serum Albumin, and Lactotransferrin Identified in Different Lactation Phases of Human Milk by Proteomics Approach.

SCOPE: Human milk (HM) has a wide range of proteins with biological and nutritional functions, essential for newborns. The roles of proteins and their proteoforms in HM are not fully understood. This study aims to assess, by 2-DE proteomics, the differential proteoforms in HM, present in colostrum (COL), transition (TRA), and mature milk (MAT), aiming to contribute to understanding neonates' protein needs. METHODS AND RESULTS: HM samples are collected from 39 healthy lactating women. COL presents the higher concentration of essential amino acids. After MALDI-MS/MS and bioinformatics analysis, proteoforms are differentially detected. Abundances of ß-casein (CSN2), α-s1 casein, and α-lactalbumin (LALBA) are higher in MAT; CSN2s are found in 11 spots and the isoforms increase in size as the pI becomes more acidic; regarding LALBA, two variant forms are found with different abundances in TRA and MAT; CSN2, LALBA, lactotransferrin (LTF), and serum albumin forms are present in all lactation phases. CONCLUSION: This study reveals differential proteoforms in COL involved in tissue growth and body development, besides essential amino acids, and, in MAT, involved in muscle mass gain, strengthening of the immune system, and energy production. The results provide new insight about proteoforms involved in maturation of the newborn's organs and systems.