Abstract EANA2024-6

On Earth, bacteria form biofilms, colonies shielded by an extracellular matrix (ECM), to protect themselves from external stresses and become more resistant to drugs, causing widespread health issues. In space, bacteria also form biofilms, which have been found to be even more virulent and resistant to external stress and antibiotics than Earth biofilm, posing a significant threat to the safety of the crew, already exacerbated by the reduction of astronauts' immune response. Moreover, the presence of biofilms poses a threat to the proper functioning instruments and equipment used in space. Therefore, it is imperative to develop new strategies to prevent biofilm formation and effectively eradicate them. Entamoeba histolytica, a parasite residing in the human colon, feeds on bacteria and occasionally causes disease. While the presence of biofilms in the gut is established, the ability of this amoeba to tackle these biofilms was previously unknown. Our research reveals that E. histolytica can dismantle biofilms of diverse bacterial origins, including multi-species biofilms, by employing potent cysteine protease (CPs) enzymes. Specifically, these CPs have been found to degrade TasA, a crucial protein component of Bacillus subtilis biofilms. Consequently, through TasA cleavage, this amoeba can infiltrate and weaken the biofilm, rendering it more susceptible to antibiotics. The efficacy of EhCPs in degrading both single and multispecies biofilms of diverse origins positions them as potent anti-biofilm agents, potentially valuable in combating biofilm formation in space environments.