Releasing incompatible males drives strong suppression across populations of wild and Wolbachia-carrying Aedes aegypti in Australia.

Releasing sterile or incompatible male insects is a proven method of population management in agricultural systems with the potential to revolutionize mosquito control. Through a collaborative venture with the "Debug" Verily Life Sciences team, we assessed the incompatible insect technique (IIT) with the mosquito vector Aedes aegypti in northern Australia in a replicated treatment control field trial. Backcrossing a US strain of Ae. aegypti carrying Wolbachia wAlbB from Aedes albopictus with a local strain, we generated a wAlbB2-F4 strain incompatible with both the wild-type (no Wolbachia) and wMel-Wolbachia Ae. aegypti now extant in North Queensland. The wAlbB2-F4 strain was manually mass reared with males separated from females using Verily sex-sorting technologies to obtain no detectable female contamination in the field. With community consent, we delivered a total of three million IIT males into three isolated landscapes of over 200 houses each, releasing ∼50 males per house three times a week over 20 wk. Detecting initial overflooding ratios of between 5:1 and 10:1, strong population declines well beyond 80% were detected across all treatment landscapes when compared to controls. Monitoring through the following season to observe the ongoing effect saw one treatment landscape devoid of adult Ae. aegypti early in the season. A second landscape showed reduced adults, and the third recovered fully. These encouraging results in suppressing both wild-type and wMel-Ae. aegypti confirms the utility of bidirectional incompatibility in the field setting, show the IIT to be robust, and indicate that the removal of this arbovirus vector from human-occupied landscapes may be achievable.

Homeostatic and circadian mechanisms of bioluminescence regulation differ between a forest and a facultative cave species of glowworm, Arachnocampa.

Glowworms, members of the keroplatid fly genus, Arachnocampa, glow to attract prey. Here we describe substantial differences in the bioluminescence regulatory systems of two species; one is a troglophile with populations both in caves and outside of caves in wet forest (Arachnocampa tasmaniensis) and the other has no known cave populations (Arachnocampa flava). We find that A. tasmaniensis is ready to initiate bioluminescence at any time darkness is encountered. In contrast, A. flava shows a homeostatic control of bioluminescence; it is unlikely to initiate bioluminescence when exposed to dark pulses during the photophase and it does so with a long latency. Another difference between the two species is that A. tasmaniensis individuals synchronize their bioluminescence in the dark zone of caves under the control of the circadian system and A. flava individuals do not synchronize to each other, rather their circadian control system entrains to the light:dark cycle to promote nocturnal bioluminescence. Consequently, we produced a phase-response curve in response to photic entrainment under constant darkness for both species. The shape of the phase-response curves differs between the two species as does the overall sensitivity to the identical entrainment conditions. The phase-response curve of A. tasmaniensis facilitates synchronization whereas that of A. flava facilitates nocturnal glowing. The two-species comparison highlights possible pathways of divergence of circadian control of physiological functions that could be associated with the extreme ecological differences experienced in cave and surface habitats.

Bioluminescence imaging in mouse models quantifies beta cell mass in the pancreas and after islet transplantation.

PURPOSE: We developed a mouse model that enables non-invasive assessment of changes in beta cell mass. PROCEDURES: We generated a transgenic mouse expressing luciferase under control of the mouse insulin I promoter [mouse insulin promoter-luciferase-Vanderbilt University (MIP-Luc-VU)] and characterized this model in mice with increased or decreased beta cell mass and after islet transplantation. RESULTS: Streptozotocin-induced, diabetic MIP-Luc-VU mice had a progressive decline in bioluminescence that correlated with a decrease in beta cell mass. MIP-Luc-VU animals fed a high-fat diet displayed a progressive increase in bioluminescence that reflected an increase in beta cell mass. MIP-Luc-VU islets transplanted beneath the renal capsule or into the liver emitted bioluminescence proportional to the number of islets transplanted and could be imaged for more than a year. CONCLUSIONS: Bioluminescence in the MIP-Luc-VU mouse model is proportional to beta cell mass in the setting of increased and decreased beta cell mass and after transplantation.