Sperm binding to porcine oviductal cells is mediated by SRCR domains contained in DMBT1.

The oviduct is an organ in which a subpopulation of sperm is stored in a reservoir, preserving its fertilizing potential. In porcine, two oviductal proteins have been identified in relation to sperm binding, Annexin A2 and Deleted in Malignant Brain Tumor 1 (DMBT1). DMBT1 is a multifunctional, multidomain glycoprotein, and the characteristics of all of its domains, as well as its carbohydrates, make them candidates for sperm binding. In this work, we challenge sperm for binding to pig oviductal cells on primary culture, after treatment with antibodies specific for the different domains present in DMBT1. Only anti-SRCR antibodies produced inhibition of sperm binding to cells. Thus, SRCR is the main domain in DMBT1 promoted sperm binding to form the reservoir in the oviduct, and this function is probably elicited through the polypeptide itself.

Annexin A2 and S100A10 in the mammalian oviduct.

In many mammals, upon entry into the female reproductive tract, a subpopulation of sperm is stored in the oviduct forming a functional reservoir. In the oviducts of pig and cow, Annexin A2 (AnxA2) has been linked to the binding of sperm. This protein may exist as a monomer or bound to S100A10 and both forms are associated with different biological functions. S100A10 has not yet been reported in the oviduct. The objective of this work is to analyze for the presence of S100A10 in the oviduct and to advance the study of AnxA2 and S100A10 in this organ. This work shows the presence of both proteins, AnxA2 and S100A10, in the oviduct of human, pig, cow, cat, dog and rabbit. At least in pig, AnxA2 is found devoid of S100A10 in the outer surface of the apical plasma membrane of oviductal epithelial cells, indicating that it binds to sperm as a monomer or in association with proteins different from S100A10. In the apical cytoplasm of pig oviductal epithelial cells, AnxA2 is associated with S100A10. In primary culture of porcine oviductal cells, the expression of ANXA2 is increased by progesterone, while the expression of S100A10 is increased by progesterone and estradiol. The widespread detection of both proteins in the oviduct of mammals indicates a probable conserved function in this organ. In summary, S100A10 and AnxA2 are widespread in the mammalian oviduct but AnxA2 binds sperm in vivo devoid of S100A10 and may be related to reservoir formation.

Cucurbit[8]uril-stabilized charge transfer complexes with diquat driven by pH: a SERS study.

In this work, we have studied the pH-dependence of the formation of DQCB[8] complexes by surface-enhanced Raman scattering (SERS) spectroscopy. The SERS spectra suggest that at acidic pH CB[8] can form a binary complex with the dication DQ(+2) while at higher pH ternary complexes with the radical cation dimer (DQ(+)˙)(2) and the radical cation-dication dimer (DQ(+)˙DQ(+2)) are formed. The pH-enhanced diquat (DQ) dimerization inside the cucurbit[8]uril cavity has not been reported until now. In addition, this study provides very valuable information regarding the use of CB[8] functionalized silver nanoparticles as SERS substrate for sensing applications.

Molecular identification of the sperm selection involved porcine sperm binding glycoprotein (SBG) as deleted in malignant brain tumors 1 (DMBT1).

Porcine sperm binding glycoprotein (SBG) is involved in sperm-oviduct interaction. Here we use mass spectrometry to identify SBG, finding peptides corresponding to deleted in malignant brain tumors 1 (DMBT1), at scavenger receptor cysteine-rich (SRCR) and CUB domains. RT-PCR allowed the cloning of unique sequences, belonging to porcine DMBT1. Western blot and immunofluorescence of oviductal tissues using anti-SBG and anti-hDMBT1 antibodies showed identical results. The biochemical characteristics of both proteins are coincident. We conclude that porcine SBG is an oviductal form of DMBT1, and thus assign this protein a novel location and function.