Modulation of mammalian sperm function by fertilization promoting peptide (FPP)

Combined Raman and polarization sensitive holographic imaging for a multimodal label-free assessment of human sperm function

Raman microspectroscopy (RM) and polarization sensitive digital holographic imaging (PSDHI) are valuable analytical tools in biological and medical research, allowing the detection of both biochemical and morphological variations of the sample without labels or long sample preparation. Here, using this multi-modal approach we analyze in vitro human sperm capacitation and the acrosome reaction induced by heparin. The multimodal microscopy provides morphofunctional information that can assess the sperms ability to respond to capacitation stimuli (sperm function). More precisely, the birefringence analysis in sperm cells can be used as an indicator of its structural normality. Indeed, digital holography applied for polarization imaging allows for revelation of the polarization state of the sample, showing a total birefringence of the sperm head in non-reacted spermatozoa, and a birefringence localized in the post-acrosomal region in reacted spermatozoa. Additionally, RM allows the detection and spectroscopic characterization of protein/lipid delocalization in the plasma and acrosomal membranes that can be used as valuable Raman biomarkers of sperm function. Interestingly, these spectral variations can be correlated with different time phases of the cell capacitation response. Although further experimentation is required, the proposed multimodal approach could represent a potential label-free diagnostic tool for use in reproductive medicine and the diagnosis of infertility.

The alphabet of intrinsic disorder: II. Various roles of glutamic acid in ordered and intrinsically disordered proteins

The ability of a protein to fold into unique functional state or to stay intrinsically disordered is encoded in its amino acid sequence. Both ordered and intrinsically disordered proteins (IDPs) are natural polypeptides that use the same arsenal of 20 proteinogenic amino acid residues as their major building blocks. The exceptional structural plasticity of IDPs, their capability to exist as heterogeneous structural ensembles and their wide array of important disorder-based biological functions that complements functional repertoire of ordered proteins are all rooted within the peculiar differential usage of these building blocks by ordered proteins and IDPs. In fact, some residues (so-called disorder-promoting residues) are noticeably more common in IDPs than in sequences of ordered proteins, which, in their turn, are enriched in several order-promoting residues. Furthermore, residues can be arranged according to their “disorder promoting potencies,” which are evaluated based on the relative abundances of various amino acids in ordered and disordered proteins. This review continues a series of publications on the roles of different amino acids in defining the phenomenon of protein intrinsic disorder and concerns glutamic acid, which is the second most disorder-promoting residue.

Ablation of paternal accessory sex glands imparts physical and behavioural abnormalities to the progeny: an in vivo study in the golden hamster

The functional significance of male accessory sex glands (ASG) remains unclear. This study explored their importance in reproduction. In previous investigations, embryos sired by males with ASG either totally or partially removed had a shift in the cell cycle and delayed cleavage during preimplantation development, higher incidence of apoptosis, early oviductal-uterine transit, higher proportion of embryo degeneration, lower implantation rate, and ultimately reduced fertility and fecundity. Some pups were born alive; but would they be normal? We hypothesized that the first generation offspring (F1) could also bear undesirable traits. To test our hypothesis, we raised and studied these F1 pups from birth to 8 weeks. We monitored physical growth and assessed behaviour such as nest patch odor preference, acoustic startle response (ASR) and exploratory activity. We detected deviations from the norm in physical growth, a premature cessation of nest patch odor preferences, accelerated acoustic startle habituation and more frequent rearing when exposed to a novel environment. In terms of structure, we found one incidence of diphallus with duplicated urethra. We concluded that sperm lacking contact with ASG secretions gave rise to progeny with abnormal traits.