Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Cold Spring Harbor Laboratory  

Electrophysiological recordings taken from the antennal nerve can provide essential information on the general auditory condition of the mosquito tested. Furthermore, electrophysiological recordings provide detailed information on what types of stimulation induce the largest nerve responses. When these are used in conjunction with a vibrometer to measure the corresponding movement of the antennal ear during stimulation, a comprehensive overview of hearing function can be obtained. This protocol can be applied to male and female adults from any mosquito strain and can be scaled relative to available resources.

DOI： 10.1101/pdb.prot108010

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3389/fcell.2023.1123738

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1186/s12929-023-00906-6

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Acoustic communication signals diversify even on short evolutionary time scales. To understand how the auditory system underlying acoustic communication could evolve, we conducted a systematic comparison of the early stages of the auditory neural circuit involved in song information processing between closely-related fruit-fly species. Male Drosophila melanogaster and D. simulans produce different sound signals during mating rituals, known as courtship songs. Female flies from these species selectively increase their receptivity when they hear songs with conspecific temporal patterns. Here, we firstly confirmed interspecific differences in temporal pattern preferences; D. simulans preferred pulse songs with longer intervals than D. melanogaster. Primary and secondary song-relay neurons, JO neurons and AMMC-B1 neurons, shared similar morphology and neurotransmitters between species. The temporal pattern preferences of AMMC-B1 neurons were also relatively similar between species, with slight but significant differences in their band-pass properties. Although the shift direction of the response property matched that of the behavior, these differences are not large enough to explain behavioral differences in song preferences. This study enhances our understanding of the conservation and diversification of the architecture of the early-stage neural circuit which processes acoustic communication signals.

DOI： 10.1038/s41598-022-27349-7

Web of Science

PubMed

Other Link： https://www.nature.com/articles/s41598-022-27349-7

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Male Aedes aegypti (Ae. aegypti) mosquitoes rely on hearing to identify conspecific females for mating, with the male attraction to the sound of flying females (“phonotaxis”) an important behavior in the initial courtship stage. Hearing thus represents a promising target for novel methods of mosquito control, and hearing behaviors (such as male phonotaxis) can be targeted via the use of sound traps. These traps unfortunately have proven to be relatively ineffective during field deployment. Shifting the target from hearing behavior to hearing function could therefore offer a novel method of interfering with Ae. aegypti mating. Numerous neurotransmitters, including serotonin (5-hydroxytryptamine, or 5-HT) and octopamine, are expressed in the male ear, with modulation of the latter proven to influence the mechanical responses of the ear to sound. The effect of serotonin modulation however remains underexplored despite its significant role in determining many key behaviors and biological processes of animals. Here we investigated the influence of serotonin on the Ae. aegypti hearing function and behaviors. Using immunohistochemistry, we found significant expression of serotonin in the male and female Ae. aegypti ears. In the male ear, presynaptic sites identified via antibody labelling showed only partial overlap with serotonin. Next, we used RT-qPCR to identify and quantify the expression levels of three different serotonin receptor families (5-HT₁, 5-HT₂, and 5-HT₇) in the mosquito heads and ears. Although all receptors were identified in the ears of both sexes, those from the 5-HT₇ family were significantly more expressed in the ears relative to the heads. We then thoracically injected serotonin-related compounds into the mosquitoes and found a significant, reversible effect of serotonin exposure on the male ear mechanical tuning frequency. Finally, oral administration of a serotonin-synthesis inhibitor altered male phonotaxis. The mosquito serotonergic system and its receptors thus represent interesting targets for novel methods of mosquito, and thus disease, control.

DOI： 10.3389/fphys.2022.931567

Web of Science

PubMed

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Background

The primary disease vectors for dengue virus (DENV) transmission between humans are the mosquitoes Aedes aegypti and Aedes albopictus, with Ae. aegypti population size strongly correlated with DENV outbreaks. When a mosquito is infected with DENV, the virus migrates from the midgut to the salivary glands to complete the transmission cycle. How the virus crosses the hemocoel, resulting in systemic infection, is still unclear however. During viral infection and migration, the innate immune system is activated in defense. As part of cellular-mediated immunity, hemocytes are known to defend against bacteria and Plasmodium infection and may also participate in defending against DENV infection. Hemocytes are categorized into three cell types: prohemocytes, granulocytes, and oenocytoids. Here, we investigated which hemocytes can be infected by DENV and compare hemocyte infection between Ae. aegypti and Ae. albopictus.

Methods

Hemocytes were collected from Ae. aegypti and Ae. albopictus mosquitoes that were intrathoracically infected with DENV2-GFP. The collected hemocytes were then identified via Giemsa staining and examined microscopically for morphological differences and viral infection.

Results

All three types of hemocytes were infected by DENV, though the predominantly infected cell type was prohemocytes. In Ae. aegypti, the highest and lowest infection rates at 7 days post infection occurred in prohemocytes and granulocytes, respectively. Prohemocytes were also the primary infection target of DENV in Ae. albopictus, with similar infection rates across the other two hemocyte groups. The ratios of hemocyte composition did not differ significantly between non-infected and infected mosquitoes for either species.

Conclusions

In this study, we showed that prohemocytes were the major type of hemocyte infected by DENV in both Ae. aegypti and Ae. albopictus. The infection rate of prohemocytes in Ae. albopictus was lower than that in Ae. aegypti, which may explain why systemic DENV infection in Ae. albopictus is less efficient than in Ae. aegypti and why Ae. albopictus is less correlated to dengue fever outbreaks. Future work in understanding the mechanisms behind these phenomena may help reduce arbovirus infection prevalence.

Graphical Abstract

DOI： 10.1186/s13071-022-05276-w

Web of Science

PubMed

Other Link： https://link.springer.com/article/10.1186/s13071-022-05276-w/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

A key component of integrated vector management strategies is the efficient implementation of mosquito traps for surveillance and control. Numerous trap types have been created with distinct designs and capture mechanisms, but identification of the most effective trap type is critical for effective implementation. For dengue vector surveillance, previous studies have demonstrated that active traps utilizing CO₂ attractant are more effective than passive traps for capturing Aedes mosquitoes. However, maintaining CO₂ supply in traps is so labor intensive as to be likely unfeasible in crowded residential areas, and it is unclear how much more effective active traps lacking attractants are than purely passive traps. In this study, we analyzed Aedes capture data collected in 2019 from six urban areas in Kaohsiung City to compare Aedes mosquito catch rates between (passive) gravitraps and (active) fan-traps. The average gravitrap index (GI) and fan-trap index (FI) values were 0.68 and 3.39 respectively at peak catch times from June to August 2019, with consistently higher FI values calculated in all areas studied. We compared trap indices to reported cases of dengue fever and correlated them with weekly fluctuations in temperature and rainfall. We found that FI trends aligned more closely with case numbers and rainfall than GI values, supporting the use of fan-traps for Aedes mosquito surveillance and control as part of broader vector management strategies. Furthermore, combining fan-trap catch data with rapid testing for dengue infections may improve the early identification and prevention of future disease outbreaks.

DOI： 10.3389/fpubh.2022.778736

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Background

Health systems face challenges to accelerate access to innovations that add value and avoid those unlikely to do so. This is very timely to the field of age-related sensorineural hearing loss (ARHL), where a significant unmet market need has been identified and sizeable investments made to promote the development of novel hearing therapeutics (NT). This study aims to apply health economic modeling to inform the development of cost-effective NT.

Methods

We developed a decision-analytic model to assess the potential costs and effects of using regenerative NT in patients ≥50 with ARHL. This was compared to the current standard of care including hearing aids and cochlear implants. Input data was collected from systematic literature searches and expert opinion. A UK NHS healthcare perspective was adopted. Three different but related analyses were performed using probabilistic modeling: (1) headroom analysis, (2) scenario analyses, and (3) threshold analyses.

Results

The headroom analysis shows an incremental net monetary benefit (iNMB) of £20,017[£11,299–£28,737] compared to the standard of care due to quality-adjusted life-years (QALY) gains and cost savings. Higher therapeutic efficacy and access for patients with all degrees of hearing loss yields higher iNMBs. Threshold analyses shows that the ceiling price of the therapeutic increases with more severe degrees of hearing loss.

Conclusion

NT for ARHL are potentially cost-effective under current willingness-to-pay (WTP) thresholds with considerable room for improvement in the current standard of care pathway. Our model can be used to help decision makers decide which therapeutics represent value for money and are worth commissioning, thereby paving the way for urgently needed NT.

DOI： 10.3389/fnins.2022.769983

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Dengue fever is one of the most severe viral diseases transmitted by Aedes mosquitoes, with traditional approaches of disease control proving insufficient to prevent significant disease burden. Release of Wolbachia-transinfected mosquitoes offers a promising alternative control methodologies; Wolbachia-transinfected female Aedes aegypti demonstrate reduced dengue virus transmission, whilst Wolbachia-transinfected males cause zygotic lethality when crossed with uninfected females, providing a method for suppressing mosquito populations. Although highly promising, the delicate nature of population control strategies and differences between local species populations means that controlled releases of Wolbachia-transinfected mosquitoes cannot be performed without extensive testing on specific local Ae. aegypti populations. In order to investigate the potential for using Wolbachia to suppress local Ae. aegypti populations in Taiwan, we performed lab-based and semi-field fitness trials. We first transinfected the Wolbachia strain wAlbB into a local Ae. aegypti population (wAlbB-Tw) and found no significant changes in lifespan, fecundity and fertility when compared to controls. In the laboratory, we found that as the proportion of released male mosquitoes carrying Wolbachia was increased, population suppression could reach up to 100%. Equivalent experiments in semi-field experiments found suppression rates of up to 70%. The release of different ratios of wAlbB-Tw males in the semi-field system provided an estimate of the optimal size of male releases. Our results indicate that wAlbB-Tw has significant potential for use in vector control strategies aimed at Ae. aegypti population suppression in Taiwan. Open field release trials are now necessary to confirm that wAlbB-Tw mediated suppression is feasible in natural environments.

DOI： 10.1371/journal.pntd.0010084

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Association for the Advancement of Science (AAAS)  

By beating their wings faster around sunset, male Anopheles mosquitoes sensitize their auditory system to female flight tones.

DOI： 10.1126/sciadv.abl4844

Web of Science

PubMed

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

The areas where dengue virus (DENV) is endemic have expanded rapidly, driven in part by the global spread of Aedes species, which act as disease vectors. DENV replicates in the mosquito midgut and is disseminated to the mosquito’s salivary glands for amplification. Thus, blocking virus infection or replication in the tissues of the mosquito may be a viable strategy for reducing the incidence of DENV transmission to humans. Here we used the mariner Mos1 transposase to create an Aedes aegypti line that expresses virus-specific miRNA hairpins capable of blocking DENV replication. These microRNA are driven by the blood-meal-inducible carboxypeptidase A promoter or by the polyubiquitin promoter. The transgenic mosquitoes exhibited significantly lower infection rates and viral titers for most DENV serotypes 7 days after receiving an infectious blood meal. The treatment was also effective at day 14 post infection after a second blood meal had been administered. In viral transmission assay, we found there was significantly reduced transmission in these lines. These transgenic mosquitoes were effective in silencing most of the DENV genome; such an approach may be employed to control a dengue fever epidemic.

DOI： 10.1038/s41598-021-03229-4

Web of Science

PubMed

Other Link： https://www.nature.com/articles/s41598-021-03229-4

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.xpro.2021.100432

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Increased levels of dysfunctional mitochondria within skeletal muscle are correlated with numerous age-related physiopathological conditions. Improving our understanding of the links between mitochondrial function and muscle proteostasis, and the role played by individual genes and regulatory networks, is essential to develop treatments for these conditions. One potential player is the mitochondrial outer membrane protein Fis1, a crucial fission factor heavily involved in mitochondrial dynamics in yeast but with an unknown role in higher-order organisms. By using Drosophila melanogaster as a model, we explored the effect of Fis1 mutations generated by transposon Minos-mediated integration. Mutants exhibited a higher ratio of damaged mitochondria with age as well as elevated reactive oxygen species levels compared with controls. This caused an increase in oxidative stress, resulting in large accumulations of ubiquitinated proteins, accelerated muscle function decline, and mitochondrial myopathies in young mutant flies. Ectopic expression of Fis1 isoforms was sufficient to suppress this phenotype. Loss of Fis1 led to unbalanced mitochondrial proteostasis within fly muscle, decreasing both flight capabilities and lifespan. Fis1 thus clearly plays a role in fly mitochondrial dynamics. Further investigations into the detailed function of Fis1 are necessary for exploring how mitochondrial function correlates with muscle health during aging.

DOI： 10.1111/acel.13379

Web of Science

PubMed

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3389/fimmu.2021.640367

Web of Science

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1186/s13071-020-04382-x

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/v12101105

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.isci.2020.101486

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.cois.2020.04.003

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media {LLC}  

DOI： 10.1038/s41467-020-16335-0

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1186/s12879-020-4942-y

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3389/fncel.2019.00418

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.heares.2019.07.003

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1097/MAO.0000000000002194

Web of Science

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Nature  

DOI： 10.1038/s41467-018-06388-7

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：{eLife} Sciences Organisation, Ltd.  

DOI： 10.7554/eLife.26402

PubMed

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Association for the Advancement of Science ({AAAS})  

DOI： 10.1126/science.1245710

PubMed