Scholarly Literature

This is a database of scholarly literature that concentrates currently on natural and engineered selfish genetic elements (gene drives).  The latest are shown here.
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From the Lab to the Field: Long-Distance Transport of Sterile Aedes Mosquitoes

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H. Maïga, M. T. Bakhoum, W. Mamai, G. Diouf, N. S. Bimbilé Somda, T. Wallner, C. Martina, S. S. Kotla, O. B. Masso, H. Yamada, B. B. D. Sow, A. G. Fall and J. Bouyer,  Insects,  14. 2023-02-18 19:03:39.
Pilot programs of the sterile insect technique (SIT) against Aedes aegypti may rely on importing significant and consistent numbers of high-quality sterile males from a distant mass rearing factory. As such, long-distance mass transport of sterile males may contribute to meet this requirement if their survival and quality are not compromised. This study therefore aimed to develop and assess a novel method for long-distance shipments of sterile male mosquitoes from the laboratory to the field. Different types of mosquito compaction boxes in addition to a simulation of the transport of marked and unmarked sterile males were assessed in terms of survival rates/recovery rates, flight ability and morphological damage to the mosquitoes. The novel mass transport protocol allowed long-distance shipments of sterile male mosquitoes for up to four days with a nonsignificant impact on survival (>90% for 48 h of transport and between 50 and 70% for 96 h depending on the type of mosquito compaction box), flight ability, and damage. In addition, a one-day recovery period for transported mosquitoes post-transport increased the escaping ability of sterile males by more than 20%. This novel system for the long-distance mass transport of mosquitoes may therefore be used to ship sterile males worldwide for journeys of two to four days. This study demonstrated that the protocol can be used for the standard mass transport of marked or unmarked chilled Aedes mosquitoes required for the SIT or other related genetic control programs.

Wbm0076, a candidate effector protein of the Wolbachia endosymbiont of Brugia malayi, disrupts eukaryotic actin dynamics

24745
M. K. Mills, L. G. McCabe, E. M. Rodrigue, K. F. Lechtreck and V. J. Starai,  PLoS Pathogens,  19:e1010777. 2023-02-17 18:26:34.
Brugia malayi, a parasitic roundworm of humans, is colonized by the obligate intracellular bacterium, Wolbachia pipientis. The symbiosis between this nematode and bacterium is essential for nematode reproduction and long-term survival in a human host. Therefore, identifying molecular mechanisms required by Wolbachia to persist in and colonize B. malayi tissues will provide new essential information regarding the basic biology of this endosymbiosis. Wolbachia utilize a Type IV secretion system to translocate so-called "effector" proteins into the cytosol of B. malayi cells to promote colonization of the eukaryotic host. However, the characterization of these Wolbachia secreted proteins has remained elusive due to the genetic intractability of both organisms. Strikingly, expression of the candidate Wolbachia Type IV-secreted effector protein, Wbm0076, in the surrogate eukaryotic cell model, Saccharomyces cerevisiae, resulted in the disruption of the yeast actin cytoskeleton and inhibition of endocytosis. Genetic analyses show that Wbm0076 is a member of the family of Wiskott-Aldrich syndrome proteins (WAS [p]), a well-conserved eukaryotic protein family required for the organization of actin skeletal structures. Thus, Wbm0076 likely plays a central role in the active cell-to-cell movement of Wolbachia throughout B. malayi tissues during nematode development. As most Wolbachia isolates sequenced to date encode at least partial orthologs of wBm0076, we find it likely that the ability of Wolbachia to directly manipulate host actin dynamics is an essential requirement of all Wolbachia endosymbioses, independent of host cell species.

How genomics can help biodiversity conservation

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K. Theissinger, C. Fernandes, G. Formenti, I. Bista, P. R. Berg, C. Bleidorn, A. Bombarely, A. Crottini, G. R. Gallo, J. A. Godoy, S. Jentoft, J. Malukiewicz, A. Mouton, R. A. Oomen, S. Paez, P. J. Palsbøll, C. Pampoulie, M. J. Ruiz-López, S. Secomandi, H,  Trends in Genetics,  2023-02-16 19:11:36.
Genomics provides effective tools to characterize biodiversity, but the full implementation of genomic techniques in practical conservation is still limited. We review some of the main approaches in biodiversity genomics available to conservationists and genomicists.High-quality, long-read sequencing and bioinformatic technologies facilitate genome sequencing and assembly for any species. We summarize how reference genomes, in conjunction with population genomic data, can contribute to biodiversity monitoring, conservation, and restoration efforts.Over the past decade, many initiatives to generate reference genomes spanning the tree of life have emerged worldwide. We call for increased integration of reference genomes and population genomics data into interdisciplinary conservation efforts to fully unlock the potential of genomics in safeguarding global biodiversity.

Evaluating the mating competency of genetically modified male mosquitoes in laboratory conditions

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B. Contreras, Z. N. Adelman and K. Chae,  Frontiers in Tropical Diseases,  4. 2023-02-13 12:01:23.
Efforts to eradicate mosquito-borne diseases have increased the demand for genetic control strategies, many of which involve the release of genetically modified (GM) mosquito males into natural populations. The first hurdle for GM males is to compete with their wild-type counterparts for access to females. Here, we introduce an eye color-based mating assay, in which both Lvp wild-type and kynurenine 3-monooxygenase (kmo)-null males compete for access to kmo-null females, and therefore the eye color phenotype (black or white) of the progeny is dependent on the parental mating pair. A series of tests addressed that male mating competitiveness between the two strains can significantly be influenced by adult density, light intensity, and mating duration. Interestingly, the mating competitiveness of males was not correlated with body size, which was negatively influenced by a high larval density. Lastly, this eye color-associated assay was applied to characterize GM mosquitoes in their mating competitiveness, establishing this method as a fast and precise way of benchmarking this fitness parameter for laboratory-raised males.

Gene Drive: Past, Present and Future Roads to Vertebrate Biocontrol

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G. R. McFarlane, C. B. A. Whitelaw and S. G. Lillico,  Applied Biosciences,  2:52-70. 2023-02-13 09:35:36.
Scientists have long sought a technology to humanely control populations of damaging invasive pests in a species-specific manner. Gene drive technology could see this become a reality. This review charts the twists and turns on the road to developing gene drives in vertebrates. We focus on rodents, as these will likely be the first targets, and trace the journey from the early understanding of selfish genetic elements to engineering gene drives in mice; before discussing future research focuses and the crucial role that public perception and governance will play in the application of this technology. The realisation of robust gene drive strategies in vertebrate pests has the potential to revolutionise biocontrol.

Review of gene drive modelling and implications for risk assessment of gene drive organisms

24722
J. L. Frieß, C. R. Lalyer, B. Giese, S. Simon and M. Otto,  Ecological Modelling,  478:110285. 2023-02-13 09:34:10.
Synthetic gene drive (GD) systems constitute a form of novel invasive environmental biotechnology with far-reaching consequences beyond those of other known genetically modified organisms (GMOs). During the last 10 years, the development of GD systems has been closely linked to mathematical modelling which can provide feedback on how to achieve gene drive spread but also may be used to predict the ecological consequences of a gene drive release. GMOs, thus also GD systems, need to pass an environmental risk assessment (ERA) prior to a release into the environment. Models in this respect may play an important role because a release of GD organisms, even at a small scale, may not be reversible. In our review, we analyse the scope and structure of existing models to examine how they may assist the ERA. Our analysis reveals that a majority of models so far are deterministic, non-spatial and not tailored for a specific target organism. Models often use simplified assumptions on the biology of the species and seem to be made to test the effectiveness of the drive. Few models go beyond this and verify whether model predictions may be realistic under field conditions. We identified four advanced models that we judged to be the most ecologically realistic and compared the implemented parameters with ERA requirements by the European Food Safety Authority (EFSA) and World Health Organization (WHO) for genetically modified insects and mosquitoes. Although a number of abiotic and biotic factors are already considered in these models, mating-related factors and traits relevant to the interactions between the GMO and target organisms and with other species are largely excluded. Overall, our results show that biological and ecological realism are still poorly realized in current models and that most models aim to predict efficacy rather than ecological effects. Given the complexity of natural ecosystems, it may not be possible to compile a single model to cover all complexities. Thus, models should be further developed with the purpose to assist specific questions related to the risk assessment of GDs. Moreover, uncertainty will be a key issue for any model used in RA and we see the need to improve this aspect when modelling gene drives.

The Anthropocene as the End of Nature? Why Recognizing Interventionism Is Key in Coming to Terms with the Anthropocene

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K. Boersma,  ENVIRONMENTAL ETHICS,  44:195-219. 2023-02-12 09:43:02.
In this article, I address and argue against the tendency to understand the anthropocene as inaugurating the end of nature. I conduct two key moves. First, by way of an engagement with the concept of anthropocene technology I explain how understanding the anthropocene as the end of nature prevents us from recognizing what the anthropocene is all about: interventionism. Secondly, I illustrate how a nondualist understanding of the human-nature relation allows us to recognize interventionism as the hallmark of the anthropocene without falling back into the hierarchical human-nature conceptions that underlie interventionism. A nondualist framework that conserves the human-nature distinction helps us in our ability to relate critically to contemporary science and technology in the anthropocene. I illustrate the conceptual narrative of the article through the specific case of gene drive technology development.

Expansion and loss of sperm nuclear basic protein genes in Drosophila correspond with genetic conflicts between sex chromosomes

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C.-H. Chang, I. Mejia Natividad and H. S. Malik,  eLife,  12:e85249. 2023-02-10 09:47:51.
Many animal species employ sperm nuclear basic proteins (SNBPs) or protamines to package sperm genomes tightly. SNBPs vary across animal lineages and evolve rapidly in mammals. We used a phylogenomic approach to investigate SNBP diversification in Drosophila species. We found that most SNBP genes in Drosophila melanogaster evolve under positive selection except for genes essential for male fertility. Unexpectedly, evolutionarily young SNBP genes are more likely to be critical for fertility than ancient, conserved SNBP genes. For example, CG30056 is dispensable for male fertility despite being one of three SNBP genes universally retained in Drosophila species. We found 19 independent SNBP gene amplification events that occurred preferentially on sex chromosomes. Conversely, the montium group of Drosophila species lost otherwise-conserved SNBP genes, coincident with an X-Y chromosomal fusion. Furthermore, SNBP genes that became linked to sex chromosomes via chromosomal fusions were more likely to degenerate or relocate back to autosomes. We hypothesize that autosomal SNBP genes suppress meiotic drive, whereas sex-chromosomal SNBP expansions lead to meiotic drive. X-Y fusions in the montium group render autosomal SNBPs dispensable by making X-versus-Y meiotic drive obsolete or costly. Thus, genetic conflicts between sex chromosomes may drive SNBP rapid evolution during spermatogenesis in Drosophila species.

When less is more: accounting for overcompensation in mosquito SIT projects

24717
J. Bouyer,  Trends in Parasitology,  2023-02-08 10:14:35.
Compensation and overcompensation under field conditions are confirmed in Aedes mosquitoes recently by Evans et al.: equal or increased densities of emerging adults may thus result from reduced larval densities. Here the consequences when applying the sterile insect technique and provide recommendations to avoid counterproductive effects are discussed.

NDUFA8 potentially rescues Wolbachia-induced cytoplasmic incompatibility in Laodelphax striatellus

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J. Chen, M. K. Wang, Q. X. Xie, X. L. Bing, T. P. Li and X. Y. Hong,  Insect Sci,  2023-02-06 18:20:35.
The endosymbiont Wolbachia manipulates host reproduction by several strategies, one of the most important of which is cytoplasmic incompatibility (CI). CI can be rescued when Wolbachia-infected (WI) males mate with females infected with the same Wolbachia strain. However, the potential rescue mechanism of CI in the small brown planthopper Laodelphax striatellus is unclear. In this study, comparative transcriptome analysis was applied to explore the effect of Wolbachia on L. striatellus eggs. A total of 1387 differentially expressed genes were identified. RNAi of seven Wolbachia-upregulated key planthopper genes reduced egg reproduction, suggesting that Wolbachia might improve fecundity in L. striatellus by affecting these seven genes. Suppressing the expression of another upregulated gene, NDUFA8 (encoding NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 8-like) by RNAi significantly increased the mortality of early embryos without affecting the number of deposited eggs. Wolbachia infection upregulated the mRNA level of NDUFA8, and dsNDUFA8 treatment of WI females re-created CI-like symptoms, suggesting that NDUFA8 is associated with the rescue phenotype. Because all L. striatellus populations worldwide are infected with Wolbachia, NDUFA8 is a potential pest control target. This article is protected by copyright. All rights reserved.

Investigating Wolbachia symbiont-mediated host protection against a bacterial pathogen using a natural Wolbachia nuclear insert

24740
C. Prigot-Maurice, B. Lheraud, S. Guéritault, S. Beltran-Bech, R. Cordaux, J. Peccoud and C. Braquart-Varnier,  Journal of Invertebrate Pathology,  197:107893. 2023-02-06 18:15:04.
Wolbachia bacterial endosymbionts provide protection against pathogens in various arthropod species but the underlying mechanisms remain misunderstood. By using a natural Wolbachia nuclear insert (f-element) in the isopod Armadillidium vulgare, we explored whether Wolbachia presence is mandatory to observe protection in this species or the presence of its genes is sufficient. We assessed survival of closely related females carrying or lacking the f-element (and lacking Wolbachia) challenged with the bacterial pathogen Salmonella enterica. Despite marginal significant effects, the f-element alone did not appear to confer survival benefits to its host, suggesting that Wolbachia presence in cells is crucial for protection.

A Zika virus-responsive sensor-effector system in Aedes aegypti

24699
S. Basu, C. M. Reitmayer, S. Lumley, B. Atkinson, M. L. Schade-Weskott, S. Rooney, W. Larner, E. E. Montiel, R. Gutierrez-Lopez, E. Levitt, H. M. Munyanduki, A. M. E. Elrefaey, A. T. Clarke, S. Koit, E. Zusinaite, R. Fragkoudis, A. Merits and L. Alphey,  bioRxiv,  2023.02.06.527261. 2023-02-06 12:38:46.
Zika virus (ZIKV) is a recently re-emerged flavivirus transmitted primarily through the bite of an infected mosquito, Aedes aegypti being the main vector. ZIKV infection is associated with a range of adverse effects; infection during pregnancy can lead to foetal abnormalities, including microcephaly. Lacking a licensed vaccine, or specific therapeutics, control of ZIKV transmission focuses on vector control. However, in most transmission settings, current methods are insufficient to successfully control ZIKV, or other similarly-transmitted arboviruses such as dengue and chikungunya viruses. This has stimulated interest in genetics-based methods, either to reduce the number of mosquitoes (population suppression), or to make mosquitoes less able to transmit (population modification). Here, we describe a method to selectively eliminate infected mosquitoes, using a virus sensor inserted into the mosquito genome and coupled to a quorum-counting lethal effector. In mosquitoes, ZIKV normally establishes persistent, lifelong infection; survival of these infected mosquitoes is crucial to transmission potential. Correspondingly, removal of infected mosquitoes can reduce vectorial capacity of a mosquito population, i.e. ability to transmit. Since relatively few mosquitoes become infected, typically <2%, engineered hypersensitivity to ZIKV would have only a modest population-level fitness cost, and lower still if transmission were successfully reduced by such means.Competing Interest StatementThe authors have declared no competing interest.

A selfish genetic element and its suppressor causes gross damage to testes in a fly

24697
S. Lyth, A. Manser, G. Hurst, T. Price and R. Verspoor,  bioRxiv,  2023.02.06.527273. 2023-02-06 12:34:06.
Selfish genetic elements (SGEs), specifically X-chromosome meiotic drive (XCMD), create huge conflicts within a hosts genome and can have profound effects on fertility. Suppressors are a common evolutionary response to XCMD to negate its costs. However, whether suppressors themselves can cause negative non-target effects remains understudied. Here, we examine whether the intragenomic conflicts created by XCMD and its suppressor affects gonad morphology in Drosophila subobscura. We found significant differences in testes, seminal vesicle, and accessory gland size depending on whether a male carried a non-driving X chromosome, an XCMD, and if the XCMD was suppressed. We also found the first evidence of extreme whole-organ damage to testes that is specifically associated with a suppressor of XCMD. Unlike other studies, our evidence suggests that XCMD in D. subobscura inflicts extreme damage on male gonads. This damage is most severe if both XCMD and its suppressor are both present. While costs of suppression have importance in theoretical models, they have largely been ignored in empirical XCMD systems. Overall, this study highlights that genetic conflict, created by SGEs and their suppressors, is a potent evolutionary force that can have major impacts on gonad development and gametogenesis.Competing Interest StatementThe authors have declared no competing interest.

Moving beyond narrow definitions of gene drive: Diverse perspectives and frames enable substantive dialogue among science and humanities teachers in the United States and United Kingdom

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S. Hartley, A. Stelmach, J. A. Delborne and S. K. Barnhill-Dilling,  Public Understanding of Science,  2023-02-06 08:31:02.
Gene drive is an emerging biotechnology with applications in global health, conservation and agriculture. Scientists are preparing for field trials, triggering debate about when and how to release gene-drive organisms. These decisions depend on public understandings of gene drive, which are shaped by language. While some studies on gene drive communication assume the need to persuade publics of expert definitions of gene drive, we highlight the importance of meaning-making in communication and engagement. We conducted focus groups with humanities and science teachers in the United Kingdom and United States to explore how different media framings stimulated discussions of gene drive. We found diversity in the value of these framings for public debate. Interestingly, the definition favoured by gene drive scientists was the least popular among participants. Rather than carefully curating language, we need opportunities for publics to make sense and negotiate the meanings of a technology on their own terms.

Pangenomic analysis of Wolbachia provides insight into the evolution of host adaptation and cytoplasmic incompatibility factor genes

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B. Liu, Y. S. Ren, C. Y. Su, Y. Abe and D. H. Zhu,  Frontiers in Microbiology,  14:1084839. 2023-02-03 09:44:36.
INTRODUCTION: The genus Wolbachia provides a typical example of intracellular bacteria that infect the germline of arthropods and filarial nematodes worldwide. Their importance as biological regulators of invertebrates, so it is particularly important to study the evolution, divergence and host adaptation of these bacteria at the genome-wide level. METHODS: Here, we used publicly available Wolbachia genomes to reconstruct their evolutionary history and explore their adaptation under host selection. RESULTS: Our findings indicate that segmental and single-gene duplications, such as DNA methylase, bZIP transcription factor, heat shock protein 90, in single monophyletic Wolbachia lineages (including supergroups A and B) may be responsible for improving the ability to adapt to a broad host range in arthropod-infecting strains. In contrast to A strains, high genetic diversity and rapidly evolving gene families occur in B strains, which may promote the ability of supergroup B strains to adapt to new hosts and their large-scale spreading. In addition, we hypothesize that there might have been two independent horizontal transfer events of cif genes in two sublineages of supergroup A strains. Interestingly, during the independent evolution of supergroup A and B strains, the rapid evolution of cif genes in supergroup B strains resulted in the loss of their functional domain, reflected in a possible decrease in the proportion of induced cytoplasmic incompatibility (CI) strains. DISCUSSION: This present study highlights for reconstructing of evolutionary history, addressing host adaptation-related evolution and exploring the origin and divergence of CI genes in each Wolbachia supergroup. Our results thus not only provide a basis for further exploring the evolutionary history of Wolbachia adaptation under host selection but also reveal a new research direction for studying the molecular regulation of Wolbachia- induced cytoplasmic incompatibility.

Horizontal gene transfer from plant to whitefly

24810
T. Islam, R. B. Azad, S. H. Kasfy, A. A. Rahman and T. Z. Khan,  Trends in Biotechnology,  2023-02-02 10:00:00.
The recent discovery of the horizontal transfer of a toxin-neutralizing gene from plant to whitefly (Bemisia tabaci), a polyphagous insect, sparked a new area of study. In this forum, we discuss some potential biotechnological applications of this newly discovered knowledge in the coevolutionary arms race between plants and whitefly.

Biological comparative study between Wolbachia-infected Aedes aegypti mosquito and Wolbachia-uninfected strain, Jeddah city, Saudi Arabia

24804
A. G. Algamdi, F. M. Shaher and J. A. Mahyoub,  Saudi J Biol Sci,  30:103581. 2023-02-02 08:32:08.
In this study, samples of Wolbachia-infected Aedes aegypti mosquitoes were collected from Al-Safa district in Jeddah city, Saudi Arabia. The presence of Wolbachia bacteria in mosquitoes was confirmed by PCR technique and they were reared and propagated in the laboratory. Comparative studies were conducted between Wolbachia-infected A. Aegypti and the Wolbachia-uninfected laboratory strain in terms of their ability to withstand drought, resist two types of insecticides and the activities of pesticide detoxification enzymes. The Wolbachia-infected A. aegypti strain proved less able to withstand the drought period, as the egg-hatching rate of the Wolbachia-uninfected strain was greater than that of the Wolbachia-infected strain after one, two and three months of dry periods. Compared to the Wolbachia-uninfected strain, the Wolbachia-infected strain demonstrated a relatively greater resistance to tested pesticides, namely Baton 100EC and Fendure 25EC which may be attributed to the higher levels of the detoxification enzymes glutathione-S-transferase and catalase and the lower levels of esterase and acetylcholine esterase.

Engineered Antiviral Sensor Targets Infected Mosquitoes

24617
E. Dalla Benetta, A. J. Lopez-Denman, H.-H. Li, R. A. Masri, D. J. Brogan, M. Bui, T. Yang, M. Li, M. Dunn, M. J. Klein, S. Jackson, K. Catalan, K. R. Blasdell, P. Tng, I. Antoshechkin, L. S. Alphey, P. N. Paradkar and O. Akbari,  bioRxiv,  2023.01.27.525922. 2023-01-27 09:22:47.
Escalating vector disease burdens pose significant global health risks, so innovative tools for targeting mosquitoes are critical. We engineered an antiviral strategy termed REAPER (vRNA Expression Activates Poisonous Effector Ribonuclease) that leverages the programmable RNA-targeting capabilities of CRISPR Cas13 and its potent collateral activity. Akin to a stealthy Trojan Horse hiding in stealth awaiting the presence of its enemy, REAPER remains concealed within the mosquito until an infectious blood meal is up taken. Upon target viral RNA infection, REAPER activates, triggering programmed destruction of its target arbovirus such as chikungunya. Consequently, Cas13 mediated RNA targeting significantly reduces viral replication and its promiscuous collateral activity can even kill infected mosquitoes. This innovative REAPER technology adds to an arsenal of effective molecular genetic tools to combat mosquito virus transmission.Competing Interest StatementO.S.A is a founder of both Agragene, Inc. and Synvect, Inc. with equity interest. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict of interest policies. L.A is an adviser to Synvect, Inc and Biocentis Ltd., with financial interest in each. All other authors declare no competing interests.

Impact of randomised wmel Wolbachia deployments on notified dengue cases and insecticide fogging for dengue control in Yogyakarta City

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C. Indriani, S. K. Tanamas, U. Khasanah, M. R. Ansari, Rubangi, W. Tantowijoyo, R. A. Ahmad, S. M. Dufault, N. P. Jewell, A. Utarini, C. P. Simmons and K. L. Anders,  Glob Health Action,  16:2166650. 2023-01-26 09:27:00.
BACKGROUND: Releases of Wolbachia (wMel)-infected Aedes aegypti mosquitoes significantly reduced the incidence of virologically confirmed dengue in a previous cluster randomised trial in Yogyakarta City, Indonesia. Following the trial, wMel releases were extended to the untreated control areas, to achieve city-wide coverage of Wolbachia. OBJECTIVE: In this predefined analysis, we evaluated the impact of the wMel deployments in Yogyakarta on dengue hemorrhagic fever (DHF) case notifications and on the frequency of perifocal insecticide spraying by public health teams. METHODS: Monthly counts of DHF cases notified to the Yogyakarta District Health Office between January 2006 and May 2022 were modelled as a function of time-varying local wMel treatment status (fully- and partially-treated vs untreated, and by quintile of wMel prevalence). The frequency of insecticide fogging in wMel-treated and untreated areas was analysed using negative binomial regression. RESULTS: Notified DHF incidence was 83% lower in fully treated vs untreated periods (IRR 0.17 [95% CI 0.14, 0.20]), and 78% lower in areas with 80-100% wMel prevalence compared to areas with 0-20% wMel (IRR 0.23 [0.17, 0.30]). A similar intervention effect was observed at 60-80% wMel prevalence as at 80-100% prevalence (76% vs 78% efficacy, respectively). Pre-intervention, insecticide fogging occurred at similar frequencies in areas later randomised to wMel-treated and untreated arms of the trial. After wMel deployment, fogging occurred significantly less frequently in treated areas (IRR 0.17 [0.10, 0.30]). CONCLUSIONS: Deployments of wMel-infected Aedes aegypti mosquitoes resulted in an 83% reduction in the application of perifocal insecticide spraying, consistent with lower dengue case notifications in wMel-treated areas. These results show that the Wolbachia intervention effect demonstrated previously in a cluster randomised trial was also measurable from routine surveillance data.

Control of Aedes mosquito populations using recombinant microalgae expressing short hairpin RNAs and their effect on plankton

24615
X. Fei, S. Xiao, X. Huang, Z. Li, X. Li, C. He, Y. Li, X. Zhang and X. Deng,  PLOS Neglected Tropical Diseases,  17:e0011109. 2023-01-26 09:15:48.
New biocontrol strategies are urgently needed to combat vector-borne infectious diseases. This study presents a low-cost method to produce a potential mosquito insecticide that utilizes the microalgae released into suburban water sources to control mosquito populations. Chlorella microalgae are ubiquitous in local waters, which were chosen as the host for genetic transfection. This species facilitated the recombinant algae to adapt to the prevailing environmental conditions with rapid growth and high relative abundance. The procedure involved microalgae RNAi-based insecticides developed using short hairpin RNAs targeting the Aedes aegypti chitin synthase A (chsa) gene in Chlorella. These insecticides effectively silenced the chsa gene, inhibiting Aedes metamorphosis in the laboratory and simulatedfield trials. This study explored the impact of recombinant microalgae on the phytoplankton and zooplankton in suburban waters. High-throughput sequencing revealed that rapid reproduction of recombinant Chlorella indirectly caused the disappearance of some phytoplankton and reduced the protozoan species. This study demonstrated that a recombinant microalgae-based insecticide could effectively reduce the population of Aedes mosquitoes in the laboratory and simulated field trials. However, the impact of this technology on the environment and ecology requires further investigation.

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