Delayed larval development in Anopheles mosquitoes deprived of Asaia bacterial symbionts
The nematode parasites Wuchereria bancrofti, Brugia malayi, and B. timori cause a human disease known as lymphatic filariasis, which afflicts approximately 120 million people worldwide. These organisms are known to contain endosymbiotic bacteria (Wolbachia) that are related to rickettsiae. It has been previously reported that tetracycline blocks the L3 to L4 molt of the filarial parasite B. malayi, and suggested that this was related to their known anti-rickettsial activity. However, this interpretation was tempered by several observations. First, Wolbachia DNA could still be detected in nematodes from tetracycline-treated cultures. In addition, chloramphenicol, which has anti-rickettsial and anti-chlamydial activity, failed to inhibit the molt. These observations could not rule out the possibility that the anti-molting activity of tetracycline is due to pharmacologic activities unrelated to its anti-rickettsial functions. This study shows that chemically modified tetracycline, which does not to have anti-microbial activity, also blocks molting.