Introduction: The Role of Microbes in Sex Reversal
Microbial communities play a vital role in animal reproductive health, yet scientists have only just begun to uncover their importance in the gonads, especially during sex differentiation. The swamp eel (Monopterus albus) stands out as a remarkable species that naturally switches sex from female to male. This unique trait provides an excellent model to study how microbes in the gonads may influence or respond to sex reversal.
Key Findings: Microbial Shifts Influence Reproductive Function
Researchers discovered that healthy swamp eel gonads house living microbial communities with microbial loads comparable to the gut, skin, and blood. In fact, over 55% of their microbial diversity overlaps with the gut and blood niches. The study found significant differences between the ovary and testis microbiomes. By isolating and injecting the ovarian-dominant bacteria Bacillus, scientists triggered microbial imbalance and metabolic shifts in the ovary. This led to altered amino acid and lipid metabolism, potentially affecting ovarian health.
Interestingly, Bacillus also suppressed sperm motility and count while causing inflammation in male testes. These findings underscore the critical influence of bacteria on sexual transition and gamete production. The results strongly indicate that ovarian-specific bacteria support ovarian function while simultaneously inhibiting male reproductive capacity, suggesting microbes actively participate in the natural sex reversal process of swamp eels.
