scholarly journals Inhibition of Asaia in Adult Mosquitoes Causes Male-Specific Mortality and Diverse Transcriptome Changes

Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 380 ◽  
Author(s):  
Maria Vittoria Mancini ◽  
Claudia Damiani ◽  
Sarah M. Short ◽  
Alessia Cappelli ◽  
Ulisse Ulissi ◽  
...  

Mosquitoes can transmit many infectious diseases, such as malaria, dengue, Zika, yellow fever, and lymphatic filariasis. Current mosquito control strategies are failing to reduce the severity of outbreaks that still cause high human morbidity and mortality worldwide. Great expectations have been placed on genetic control methods. Among other methods, genetic modification of the bacteria colonizing different mosquito species and expressing anti-pathogen molecules may represent an innovative tool to combat mosquito-borne diseases. Nevertheless, this emerging approach, known as paratransgenesis, requires a detailed understanding of the mosquito microbiota and an accurate characterization of selected bacteria candidates. The acetic acid bacteria Asaia is a promising candidate for paratransgenic approaches. We have previously reported that Asaia symbionts play a beneficial role in the normal development of Anopheles mosquito larvae, but no study has yet investigated the role(s) of Asaia in adult mosquito biology. Here we report evidence on how treatment with a highly specific anti-Asaia monoclonal antibody impacts the survival and physiology of adult Anopheles stephensi mosquitoes. Our findings offer useful insight on the role of Asaia in several physiological systems of adult mosquitoes, where the influence differs between males and females.

2020 ◽  
Vol 10 (4) ◽  
pp. 1353-1360 ◽  
Author(s):  
Vanessa M. Macias ◽  
Sage McKeand ◽  
Duverney Chaverra-Rodriguez ◽  
Grant L. Hughes ◽  
Aniko Fazekas ◽  
...  

Innovative tools are essential for advancing malaria control and depend on an understanding of molecular mechanisms governing transmission of malaria parasites by Anopheles mosquitoes. CRISPR/Cas9-based gene disruption is a powerful method to uncover underlying biology of vector-pathogen interactions and can itself form the basis of mosquito control strategies. However, embryo injection methods used to genetically manipulate mosquitoes (especially Anopheles) are difficult and inefficient, particularly for non-specialist laboratories. Here, we adapted the ReMOT Control (Receptor-mediated Ovary Transduction of Cargo) technique to deliver Cas9 ribonucleoprotein complex to adult mosquito ovaries, generating targeted and heritable mutations in the malaria vector Anopheles stephensi without injecting embryos. In Anopheles, ReMOT Control gene editing was as efficient as standard embryo injections. The application of ReMOT Control to Anopheles opens the power of CRISPR/Cas9 methods to malaria laboratories that lack the equipment or expertise to perform embryo injections and establishes the flexibility of ReMOT Control for diverse mosquito species.


Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 947
Author(s):  
Rishi Kondapaneni ◽  
Ashley N. Malcolm ◽  
Brian M. Vazquez ◽  
Eric Zeng ◽  
Tse-Yu Chen ◽  
...  

Florida lies within a subtropical region where the climate allows diverse mosquito species including invasive species to thrive year-round. As of 2021, there are currently 66 state-approved Florida Mosquito Control Districts, which are major stakeholders for Florida public universities engaged in mosquito research. Florida is one of the few states with extensive organized mosquito control programs. The Florida State Government and Florida Mosquito Control Districts have long histories of collaboration with research institutions. During fall 2020, we carried out a survey to collect baseline data on the current control priorities from Florida Mosquito Control Districts relating to (1) priority control species, (2) common adult and larval control methods, and (3) major research questions to address that will improve their control and surveillance programs. The survey data showed that a total of 17 distinct mosquito species were considered to be priority control targets, with many of these species being understudied. The most common control approaches included truck-mounted ultra-low-volume adulticiding and biopesticide-based larviciding. The districts held interest in diverse research questions, with many prioritizing studies on basic science questions to help develop evidence-based control strategies. Our data highlight the fact that mosquito control approaches and priorities differ greatly between districts and provide an important point of comparison for other regions investing in mosquito control, particularly those with similar ecological settings, and great diversity of potential mosquito vectors, such as in Florida. Our findings highlight a need for greater alignment of research priorities between mosquito control and mosquito research. In particular, we note a need to prioritize filling knowledge gaps relating to understudied mosquito species that have been implicated in arbovirus transmission.


Insects ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 173 ◽  
Author(s):  
Samuel Karungu ◽  
Evans Atoni ◽  
Joseph Ogalo ◽  
Caroline Mwaliko ◽  
Bernard Agwanda ◽  
...  

Kenya is among the most affected tropical countries with pathogen transmitting Culicidae vectors. For decades, insect vectors have contributed to the emergence and distribution of viral and parasitic pathogens. Outbreaks and diseases have a great impact on a country’s economy, as resources that would otherwise be used for developmental projects are redirected to curb hospitalization cases and manage outbreaks. Infected invasive mosquito species have been shown to increasingly cross both local and global boarders due to the presence of increased environmental changes, trade, and tourism. In Kenya, there have been several mosquito-borne disease outbreaks such as the recent outbreaks along the coast of Kenya, involving chikungunya and dengue. This certainly calls for the implementation of strategies aimed at strengthening integrated vector management programs. In this review, we look at mosquitoes of public health concern in Kenya, while highlighting the pathogens they have been linked with over the years and across various regions. In addition, the major strategies that have previously been used in mosquito control and what more could be done to reduce or combat the menace caused by these hematophagous vectors are presented.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Nayana Gunathilaka ◽  
Koshila Ranasinghe ◽  
Deepika Amarasinghe ◽  
Wasana Rodrigo ◽  
Harendra Mallawarachchi ◽  
...  

Background. Larval and adult mosquito stages harbor different extracellular microbes exhibiting various functions in their digestive tract including host-parasite interactions. Midgut symbiotic bacteria can be genetically exploited to express molecules within the vectors, altering vector competency and potential for disease transmission. Therefore, identification of mosquito gut inhabiting microbiota is of ample importance before developing novel vector control strategies that involve modification of vectors. Method. Adult mosquitoes of Culex tritaeniorhynchus, Culex gelidus, and Mansonia annulifera were collected from selected Medical Officer of Health (MOH) areas in the Gampaha district of Sri Lanka. Midgut lysates of the field-caught non-blood-fed female mosquitoes were cultured in Plate Count Agar medium, and Prokaryotic 16S ribosomal RNA partial genes of the isolated bacteria colonies were amplified followed by DNA sequencing. Diversity indices were used to assess the diversity and richness of the bacterial isolates in three mosquito species. The distribution pattern of bacterial isolates between different mosquito species was assessed by Distance-Based Redundancy Analysis (dbRDA). Results. A total of 20 bacterial species (Staphylococcus pasteuri, Bacillus megaterium, Staphylococcus cohnii, Pantoea dispersa, Staphylococcus chromogenes, Bacillus aquimaris, Staphylococcus arlettae, Staphylococcus sciuri, Staphylococcus warneri, Moraxella osloensis, Enterobacter sp., Klebsiella michiganensis, Staphylococcus hominis, Staphylococcus saprophyticus, Streptomyces sp., Bacillus niacin, Cedecea neteri, Micrococcus luteus, Lysinibacillus sphaericus, and Bacillus licheniformis) were identified. All of these species belonged to three phyla, Proteobacteria, Firmicutes, and Actinobacteria, out of which phylum Firmicutes (71.1%) was the most prominent. The least number of species was recorded from Actinobacteria. The relative distribution of midgut microbes in different mosquito species differed significantly among mosquito species (Chi-square, χ2=486.091; df=36; P≤0.001). Midgut microbiota of Cx. tritaeniorhynchus and Cx. gelidus indicated a similarity of 21.51%, while Ma. annulifera shared a similarity of 6.92% with the cluster of above two species. The gut microbiota of Cx. tritaeniorhynchus was also significantly more diverse and more evenly distributed compared to Ma. annulifera. Simpson’s diversity, Margalef’s diversity, and Menhinick’s diversity indices were higher in Cx. gelidus. Of the recorded species, P. dispersa and strains of nonpathogenic species in Bacillaceae family (B. megaterium, B. niacini, B. licheniformis, and L. sphaericus) can be recommended as potential candidates for paratransgenesis. Conclusion. The relative distribution of midgut microbes in different mosquito species differed significantly among the three studied adult mosquito species. The present data strongly encourage further investigations to explore the potential usage of these microbes through paratransgenic approach for novel eco-friendly vector control strategies.


Author(s):  
Brendan J Trewin ◽  
Daniel E Pagendam ◽  
Myron P Zalucki ◽  
Jonathan M Darbro ◽  
Gregor J Devine ◽  
...  

Abstract Urban landscape features play an important role in the distribution and population spread of mosquito vectors. Furthermore, current insecticide and novel rear-and-release strategies for urban mosquito management rarely consider the spatial structure of the landscape when applying control practices. Here, we undertake a mark-recapture experiment to examine how urban features influence the movement and distribution of Australian container-inhabiting Aedes vectors. We pay attention to the role of semipermanent water storage containers, called rainwater tanks, and the influence of movement barriers, such as roads, on the spread and distribution of vector populations. Results suggest that Aedes aegypti (Linnaeus) (Diptera: Culicidae) were more likely to be captured around rainwater tanks, and that released males travel throughout residential blocks but do not cross roads. Conversely, female Aedes notoscriptus (Skuse) (Diptera: Culicidae) movement was uninhibited by roads and rainwater tanks did not influence female distribution or oviposition behavior. Using an isotropic Gaussian kernel framework, we show that vector movement is likely to be greater when applying a temporal effect, than when estimated by traditional methods. We conclude that a greater understanding on the role of urban features on vector movement will be important in the new age of rear-and-release mosquito control strategies, particularly those where estimations of movement are important for ensuring efficacy of application.


2020 ◽  
Vol 117 (30) ◽  
pp. 17702-17709 ◽  
Author(s):  
Azadeh Aryan ◽  
Michelle A. E. Anderson ◽  
James K. Biedler ◽  
Yumin Qi ◽  
Justin M. Overcash ◽  
...  

A dominant male-determining locus (M-locus) establishes the male sex (M/m) in the yellow fever mosquito,Aedes aegypti.Nix, a gene in the M-locus, was shown to be a male-determining factor (M factor) as somatic knockout ofNixled to feminized males (M/m) while transient expression ofNixresulted in partially masculinized females (m/m), with male reproductive organs but retained female antennae. It was not clear whether any of the other 29 genes in the 1.3-Mb M-locus are also needed for complete sex-conversion. Here, we report the generation of multiple transgenic lines that expressNixunder the control of its own promoter. Genetic and molecular analyses of these lines provided insights unattainable from previous transient experiments. We show that theNixtransgene alone, in the absence of the M-locus, was sufficient to convert females into males with all male-specific sexually dimorphic features and male-like gene expression. The converted m/m males are flightless, unable to perform the nuptial flight required for mating. However, they were able to father sex-converted progeny when presented with cold-anesthetized wild-type females. We show thatmyo-sex, a myosin heavy-chain gene also in the M-locus, was required for male flight as knockout ofmyo-sexrendered wild-type males flightless. We also show thatNix-mediated female-to-male conversion was 100% penetrant and stable over many generations. Therefore,Nixhas great potential for developing mosquito control strategies to reduce vector populations by female-to-male sex conversion, or to aid in a sterile insect technique that requires releasing only non-biting males.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Elijah O. Juma ◽  
Chang-Hyun Kim ◽  
Christopher Dunlap ◽  
Brian F. Allan ◽  
Chris M. Stone

Abstract Background The bacterial communities associated with mosquito eggs are an essential component of the mosquito microbiota, yet there are few studies characterizing and comparing the microbiota of mosquito eggs to other host tissues. Methods We sampled gravid female Culex pipiens L. and Culex restuans Theobald from the field, allowed them to oviposit in the laboratory, and characterized the bacterial communities associated with their egg rafts and midguts for comparison through MiSeq sequencing of the 16S rRNA gene. Results Bacterial richness was higher in egg rafts than in midguts for both species, and higher in Cx pipiens than Cx. restuans. The midgut samples of Cx. pipiens and Cx. restuans were dominated by Providencia. Culex pipiens and Cx. restuans egg rafts samples were dominated by Ralstonia and Novosphingobium, respectively. NMDS ordination based on Bray-Curtis distance matrix revealed that egg-raft samples, or midgut tissues harbored similar bacterial communities regardless of the mosquito species. Within each mosquito species, there was a distinct clustering of bacterial communities between egg raft and midgut tissues. Conclusion These findings expand the list of described bacterial communities associated with Cx. pipiens and Cx. restuans and the additional characterization of the egg raft bacterial communities facilitates comparative analysis of mosquito host tissues, providing a basis for future studies seeking to understand any functional role of the bacterial communities in mosquito biology.


2020 ◽  
Author(s):  
Elijah O. Juma ◽  
Chang-Hyun Kim ◽  
Christopher Dunlap ◽  
Brian F. Allan ◽  
Chris M. Stone

AbstractBackgroundThe bacterial communities associated with mosquito eggs are an essential component of the mosquito microbiota, yet there are few studies characterizing and comparing the microbiota of mosquito eggs to other host tissues.MethodsWe sampled gravid female Culex pipiens and Culex restuans from the field, allowed them to oviposit in the laboratory, and characterized the microbiota associated with their egg rafts and midguts for comparison through MiSeq sequencing of the 16S rRNA gene.ResultsBacterial richness was higher in egg rafts than in midguts for both species, and higher in Cx pipiens L. than Cx. restuans. The midgut samples of Cx. pipiens and Cx. restuans were dominated by Providencia. Culex pipiens L. and Cx. restuans egg rafts samples were dominated by Ralstonia and Novosphingobium, respectively. NMDS ordination based on Bray-Curtis distance matrix revealed that egg raft samples, or midgut tissues harbored similar bacterial communities regardless of the mosquito species. Within each mosquito species, there were distinct clustering of bacterial communities between egg raft and midgut tissues.ConclusionThese findings expand the list of described bacterial communities associated with Cx. pipiens L. and Cx. restuans and the additional characterization of the egg raft bacterial communities facilitates comparative analysis of mosquito host tissues, providing a basis for future studies seeking to understand any functional role of microbiota in mosquito biology.


2021 ◽  
Vol 15 (8) ◽  
pp. e0009438
Author(s):  
Isik Unlu ◽  
Ary Faraji ◽  
Nicholas Indelicato ◽  
James R. McNelly

Background Aedes (Stegomyia) albopictus (Skuse) impacts human outdoor activity because of its aggressive biting behavior, and as a major vector of mosquito-borne diseases, it is also of public health importance. Although most mosquito species exhibit crepuscular activity by primarily host seeking at dawn and dusk, Ae. albopictus has been traditionally characterized as a diurnal or day-biting mosquito. With the global expansion and increased involvement of Ae. albopictus in mosquito-borne diseases, it is imperative to elucidate the diel activity of this species, particularly in newly invaded areas. Methodology and principal findings Human sweep netting and carbon dioxide-baited rotator traps were used to evaluate the diel activity of Ae. albopictus in two study sites. Both trapping methods were used in New Jersey’s Mercer County, USA (temperate/urban), while only human sweep netting was used in Florida’s Volusia County, USA (subtropical/suburban). Human sweep netting was performed to determine adult mosquito activity at Sunrise, Solar Noon, Sunset, and Lunar Midnight. Because New Jersey is in a temperate area, diel activity was investigated during the early season (3–19 July), peak season (25 July-19 September), and late season (22 September- 22 October). Aedes albopictus showed the highest activity during peak and late seasons at Solar Noon (P < 0.05). At Sunrise and Sunset during the peak season, Ae. albopictus activity was similar. Lunar Midnight activity was significantly lower than Sunrise and Solar Noon (P < 0.05) but was similar to that of Sunset. In the late season, the highest activity was observed during Solar Noon while the least activity was observed during Sunrise and Lunar Midnight (P<0.05). Bottle rotator traps used in conjunction with the human sweep net technique exhibited similar results. Seasonal activity was not differentiated in Florida due to the consistent subtropical climate. The highest adult activity was observed at Sunrise using human sweep netting, but it was not significantly different from Solar Noon and Sunset. The lowest adult activity was observed at Lunar Midnight; however, it was not significantly different from Solar Noon and Sunset. These results provide evidence that the diel activity of Ae. albopictus, contrary to the common perception of its diurnal activity, is much more varied. Conclusion/Significance Involvement of Ae. albopictus in the transmission of debilitating mosquito-borne pathogens such as chikungunya, dengue, and Zika virus, coupled with its affinity to thrive in human peridomestic environments, substantiates that our findings have global implications in areas where Ae. albopictus populations established. It also highlights the importance of behavioral studies of vector species which will not only help mosquito control professionals plan the timing of their control efforts but also provides empirical evidence against conventional wisdoms that may unjustly persist within public health stewards.


2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Bahadin Salavati ◽  
AMIR HOSSEIN ZAHIRNIA ◽  
Hassan Nasirian ◽  
SHAHYAD AZARI-HAMIDIAN

Abstract. Salavati B, Zahirnia AH, Nasirian H, Hamidian SA. 2021. Trend of mosquito (Diptera: Culicidae) monthly distribution in Sanandaj County of Iran. Biodiversitas 22: 4705-4715. Mosquitoes are the most significant arthropods of medical importance due to their burden of transmitting pathogens and parasites. The present study was designed to investigate the distribution of mosquitos (Diptera: Culicidae) in Sanandaj County in 2018. Sanandaj County was divided into four areas in rural and urban areas, including north, south, east, and west. Four rural and urban areas were randomly selected from four geographical directions. A sampling of larval and adult mosquitoes was performed using standard methods. The dipping technique was used to collect the mosquito larvae. A sampling of adult mosquitoes was performed during feeding on humans and animal baits and resting in the natural indoors, outdoors, and artificial areas. Light traps were also used to collect adult mosquitoes. The larval and adult specimens were identified using the morphology-based key. In total, nine mosquito species, including Anopheles maculipennis s.l., Anopheles superpictus s.l., Culiseta longiareolata, Culiseta subochrea, Culex hortensis, Culex mimeticus, Culex modestus, Culex pipiens, and Culex theileri were inhabited in Sanandaj County. The larval and adult mosquito species trend remains constant for at least 6 months of a year, from May to October. One-way ANOVA didn't reveal a significant difference between mosquito breeding places' habitats and water types, mosquito localities and life stages, monthly mosquito distribution, and adult mosquito resting places. The frequency trends of larval and adult mosquito species remain constant at least for 6 months of a year. It needs to be ready for timely mosquito control measures.


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