Drosophila Sex Peptide Controls the Assembly of Lipid Microcarriers in Seminal Fluid

Seminal fluid plays an essential role in promoting male reproductive success and modulating female physiology and behaviour. In the fruit fly, Drosophila melanogaster, Sex Peptide (SP) is the best-characterised protein mediator of these effects. It is secreted from the paired male accessory glands (AGs), which, like the mammalian prostate and seminal vesicles, generate most of the seminal fluid contents. After mating, SP binds to spermatozoa and is retained in the female sperm storage organs. It is gradually released by proteolytic cleavage and induces several long-term post-mating responses including ovulation, elevated feeding and reduced receptivity to remating, primarily signalling through the SP receptor (SPR). Here, we demonstrate a previously unsuspected SPR-independent function for SP. We show that, in the AG lumen, SP and secreted proteins with membrane-binding anchors are carried on abundant, large neutral lipid-containing microcarriers, also found in other SP-expressing Drosophila species. These microcarriers are transferred to females during mating, where they rapidly disassemble. Remarkably, SP is a key assembly factor for microcarriers and is also required for the female disassembly process to occur normally. Males expressing non-functional SP mutant proteins that affect SP’s binding to and release from sperm in females also do not produce normal microcarriers, suggesting that this male-specific defect contributes to the resulting widespread defects in ejaculate function. Our data therefore reveal a novel role for SP in formation of seminal macromolecular assemblies, which may explain the presence of SP in Drosophila species, which lack the signalling functions seen in D. melanogaster.Significance StatementSeminal fluid plays a critical role in reprogramming female physiology and behaviour to promote male reproductive success. We show in the fruit fly that specific seminal proteins, including the archetypal ‘female-reprogramming’ molecule Sex Peptide, are stored in male seminal secretions in association with large neutral lipid-containing microcarriers, which rapidly disperse in females. Related structures are also observed in other Sex Peptide-expressing Drosophila species. Males lacking Sex Peptide have structurally defective microcarriers, leading to abnormal cargo loading and transfer to females. Our data reveal that this key signalling molecule in Drosophila seminal fluid is also a microcarrier assembly factor that controls transfer of other seminal factors, and that this may be a more evolutionarily ancient role of this protein.

Trans-athletes in elite sport: inclusion and fairness

We support gender equality and freedoms in cases in which ‘like equals like’. Such inclusion is central to a progressive society. However, inclusion could potentially conflict with fairness in cases concerning transgendered athletes in elite sport. Accepted science regarding male and female physiology suggests that transwomen have an advantage over their cisgendered counterparts. This advantage stems from relatively high testosterone levels and prior male physiology of transwomen. Conversely, transmen who wish to compete in the men's division may be disadvantaged in comparison with cismen. Hence, while inclusion supports transwomen and transmen competing in the division that matches their gender identity, this may not satisfy the principle of fairness. We reason that transwomen and cismen are not only advantaged, but unfairly advantaged, and propose that the gender binary in elite sport should be replaced with a nuanced algorithm that accounts for both physiological and social parameters. As the algorithm would be applied to all athletes, it would be both inclusive and fair.

Unveiling the Role of Prolactin and its Receptor in Male Reproduction

Prolactin is a peptide hormone known to have multiple functions. However, the role of prolactin has been extensively studied only in female physiology and its function in male reproduction still remains majorly unexplored. Studies in rodents and humans have demonstrated the presence of prolactin and its receptor in testes, thereby suggesting a possible role during spermatogenesis. Experimental evidences from prolactin and prolactin receptor deficient male rodent models as well as studies done in hypo- and hyper-prolactinemic males hint at neuroendocrine and reproductive abnormalities. Nonetheless, there still remains a lot of ambiguity on the exact role of prolactin and its receptor in male reproduction. This review summarizes in depth on the role of prolactin in spermatogenesis.

Gender in the Temple: Women's Ailments in the Epidaurian Miracle Cures

This paper compares the cases of female ailments recorded in the Epidaurian Miracles Cures (iamata) with the theory and therapeutics of the Hippocratic gynecological texts as a means of testing the extent of the assumptions shared between temple and Hippocratic medicine. I argue that where temple and Hippocratic practice hold common ground, it is readily explicable through widely circulating and historically rooted cultural presuppositions regarding female physiology and pathology, rather than through scientific borrowings. Rather than representing complementary outlets of medical care in which Asklepios specialized in “hopeless” cases, I suggest that the iamata permit us to observe a process in which parallel medical traditions branched out from a common cultural substratum, and that more nuance is required in framing the relationship between Greek naturalist and religious medicine.