Biology subjects

Albert, J. T.

Publications and source records attributed to Albert, J. T..

5 recordsLinked to original sources

bioRxiv2025

Using a female-specific isoform of doublesex to explore male-specific hearing in mosquitoes

Animal reproduction relies on elaborate divisions of labour and multiple dimorphisms between the sexes. Primary dimorphisms affect core elements of reproduction, secondary dimorphisms affect more indirect traits, including complex behaviours. In disease-transmitting mosquitoes, males locate females acoustically prior to copulation (phonotaxis). No comparable acoustic behaviour is known for females. As a result, the males ears - and hearing performance - have evolved to become substantially more complex. Sex-specific hearing in mosquitoes is in part controlled by the doublesex (dsx) gene. Intriguingly, dsx forms a linker between primary and secondary dimorphisms: spermatogenesis and ear morphogenesis share considerable molecular overlap and both depend on dsx expression patterns. We have combined transcriptomics with functional-anatomical analyses to dissect dsx-dependent hearing in the malaria mosquito Anopheles gambiae. By cross-linking our auditory findings to the genetic bases of spermatogenesis we advance the molecular understanding of sex-specific hearing mechanisms in insects, highlighting the special roles of ciliary factors therein. HighlightsO_LIDisruption of the female-specific exon of the doublesex gene alters hearing in female Anopheles gambiae mosquitoes C_LIO_LIFemale mutant ears are anatomically and functionally distinct from both wild-type male and female; they show a substantial, but incomplete, masculinisation C_LIO_LIContrary to males, and similarly to females, the flagella of female mutants do not exhibit Self-Sustained Oscillations (SSOs) C_LIO_LITranscriptomic comparisons of ears uncovered molecular bases of auditory maleness, these were closely linked to molecular machinery of ciliary function C_LIO_LIComparisons with existing transcriptome from male testes revealed a substantial overlap between male ear and testicular ciliary motility machineries C_LI

neuroscience↗

bioRxiv2024

The GABAA receptor RDL modulates the auditory sensitivity of malaria mosquitoes.

Malaria mosquitoes mate in crowded, and noisy, swarms. A vital stage of their precopulatory behaviour involves detecting the faint flight tone of a mating partner amidst the noise from hundreds of other mosquitoes. This exquisite sensory performance is enabled by a complex auditory system with remarkable features. One such feature is their vast efferent control system, which provides the mosquito ear with the required plasticity to adapt to various external and internal changes. In this paper, we study the auditory role of GABA, one of the main efferent signalling molecules in the mosquito ear, and its interactions with octopamine, another neurotransmitter of the efferent network. We show that GABA is released in the malaria mosquito auditory nerve and that GABA receptors are expressed in the ear, including the GABAA receptor Resistance to Dieldrin (RDL), a target for the evolution of insecticide resistance. Using picrotoxin to antagonize RDL receptors, we discovered multiple auditory effects of GABA at the mechanical and electrical level. At the mechanical level, blocking RDL promotes the erection of antennal fibrillae and the cessation of flagellar self-sustained oscillations. These effects are not observed in knockouts of the octopamine receptor AgOct{beta}2, suggesting that RDL auditory mechanical effects are mediated through octopamine release in the mosquito ear. Electrically, picrotoxin injection increases the spontaneous firing of auditory neurons and direct current (DC) responses of the nerve to mechanical stimulation both in wildtype and AgOct{beta}2 mutants, indicating that RDL may also modulate auditory sensitivity via octopamine-independent pathways. In summary, our experiments uncover distinct auditory roles of GABA, as well as synergistic roles with octopamine. The data show a fundamental role of RDL in controlling the auditory function of malaria mosquitoes and implicate RDL signalling in mating of natural malaria mosquito populations.

neuroscience↗

bioRxiv2022

A novel beta-adrenergic like octopamine receptor modulates the audition of malaria mosquitoes and serves as insecticide target

Hearing is an essential sense in the life cycle of malaria mosquitoes. Within large swarms formed transiently at dusk, mosquitoes acoustically recognize their mating partners by their wingbeats. Indeed, malaria mosquitoes only respond to the flight tones of mating partners during swarm time. This phenomenon implies a sophisticated context- and time-dependent modulation of mosquito audition, the mechanisms of which are still largely unknown. Using transcriptomics, we identify a complex network of candidate neuromodulators regulating mosquito hearing. Among them, octopamine stands out as regulator of the auditory performance during swarm time. To explore octopamines roles in mosquito hearing, we carried out an in-depth analysis of octopamine-mediated effects on auditory function. We found that octopamine affects the properties of the mosquito ear on multiple levels: it modulates the tuning and stiffness of the flagellar sound receiver and it controls the erection of antennal fibrillae in males. We found that two different receptors are driving octopamines auditory roles, including a novel beta octopamine receptor. We also demonstrate that the octopaminergic auditory control system can be targeted by insecticides. Our findings identify octopamine signalling as a key component of hearing and mating partner detection in malaria mosquitoes, and as a potential novel target for mosquito control.

neuroscience↗

bioRxiv2021

Flight-tone mediated circadian control of audibility in mating swarms of Anopheles mosquitoes

Mating swarms of malaria mosquitoes form every day at sunset throughout the tropical world, they typically last less than 30 minutes. Activity patterns must thus be highly synchronized between the sexes. Moreover, males must be able to identify the few sporadically entering females by detecting the females faint flight tones. We here show that the Anopheles circadian clock ensures a tight synchrony of male and female activity and -importantly - also retunes the males acoustic detection system: by lifting their own flight tones at dusk, males actively enhance the audibility of females. The reported phenomenon of harmonic convergence is a random by-product of the mosquitoes flight tone variance. Intriguingly, flight tones of individual mosquitoes occupy narrow -partly non-overlapping-frequency ranges, suggesting that the audibility of individual females varies across males. One Sentence SummaryMale mosquitoes sharpen their hearing at sunset.

neuroscience↗

bioRxiv2019

Homeostatic maintenance and age-related functional decline in the Drosophila ear

The widespread loss of hearing is one of the major threats to future wellbeing in ageing human societies. Amongst its various forms, age-related hearing loss (ARHL) carries the vast bulk of the global disease burden. The causes for the terminal decline of auditory function, however, are as unknown as the mechanisms that maintain sensitive hearing before its breakdown. We here present an in-depth analysis of maintenance and ageing in the auditory system of the fruit fly Drosophila melanogaster. We show that Drosophila, just like humans, display ARHL and that their auditory life span is homeostatically supported by a set of evolutionarily conserved transcription factors. The transcription factors Onecut (closest human orthologues: ONECUT2, ONECUT3), Optix (SIX3, SIX6), Worniu (SNAI2) and Amos (ATOH1, ATOH7, NEUROD1) emerged as key regulators acting upstream of core sensory genes, including components of the flys molecular machinery for auditory transduction and amplification.

neuroscience↗