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1.
Proc Natl Acad Sci U S A ; 117(39): 24475-24483, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32913052

RESUMO

Wolbachia-infected mosquitoes are refractory to flavivirus infections, but the role of lipids in Wolbachia-mediated virus blocking remains to be elucidated. Here, we use liquid chromatography mass spectrometry to provide a comprehensive picture of the lipidome of Aedes aegypti (Aag2) cells infected with Wolbachia only, either dengue or Zika virus only, and Wolbachia-infected Aag2 cells superinfected with either dengue or Zika virus. This approach identifies a class of lipids, acyl-carnitines, as being down-regulated during Wolbachia infection. Furthermore, treatment with an acyl-carnitine inhibitor assigns a crucial role for acyl-carnitines in the replication of dengue and Zika viruses. In contrast, depletion of acyl-carnitines increases Wolbachia density while addition of commercially available acyl-carnitines impairs Wolbachia production. Finally, we show an increase in flavivirus infection of Wolbachia-infected cells with the addition of acyl-carnitines. This study uncovers a previously unknown role for acyl-carnitines in this tripartite interaction that suggests an important and broad mechanism that underpins Wolbachia-mediated pathogen blocking.


Assuntos
Aedes/microbiologia , Aedes/virologia , Carnitina/metabolismo , Wolbachia/fisiologia , Zika virus/fisiologia , Aedes/química , Aedes/metabolismo , Animais , Carnitina/química , Feminino , Mosquitos Vetores/química , Mosquitos Vetores/metabolismo , Mosquitos Vetores/microbiologia , Mosquitos Vetores/virologia
2.
J Virol ; 95(13): e0220320, 2021 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-33853965

RESUMO

Recent field trials have demonstrated that dengue incidence can be substantially reduced by introgressing strains of the endosymbiotic bacterium Wolbachia into Aedes aegypti mosquito populations. This strategy relies on Wolbachia reducing the susceptibility of Ae. aegypti to disseminated infection by positive-sense RNA viruses like dengue. However, RNA viruses are well known to adapt to antiviral pressures. Here, we review the viral infection stages where selection for Wolbachia-resistant virus variants could occur. We also consider the genetic constraints imposed on viruses that alternate between vertebrate and invertebrate hosts, and the likely selection pressures to which dengue virus might adapt in order to be effectively transmitted by Ae. aegypti that carry Wolbachia. While there are hurdles to dengue viruses developing resistance to Wolbachia, we suggest that long-term surveillance for resistant viruses should be an integral component of Wolbachia-introgression biocontrol programs.


Assuntos
Adaptação Fisiológica/fisiologia , Aedes/microbiologia , Vírus da Dengue/crescimento & desenvolvimento , Dengue/prevenção & controle , Wolbachia/metabolismo , Aedes/efeitos dos fármacos , Animais , Dengue/patologia , Dengue/transmissão , Drosophila/microbiologia , Evolução Molecular , Humanos , Resistência a Inseticidas/fisiologia , Mosquitos Vetores/microbiologia , Seleção Genética/genética
3.
PLoS Pathog ; 16(7): e1008410, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32726353

RESUMO

The bacterial endosymbiont Wolbachia is a biocontrol tool that inhibits the ability of the Aedes aegypti mosquito to transmit positive-sense RNA viruses such as dengue and Zika. Growing evidence indicates that when Wolbachia strains wMel or wAlbB are introduced into local mosquito populations, human dengue incidence is reduced. Despite the success of this novel intervention, we still do not fully understand how Wolbachia protects mosquitoes from viral infection. Here, we demonstrate that the Wolbachia strain wPip does not inhibit virus infection in Ae. aegypti. We have leveraged this novel finding, and a panel of Ae. aegypti lines carrying virus-inhibitory (wMel and wAlbB) and non-inhibitory (wPip) strains in a common genetic background, to rigorously test a number of hypotheses about the mechanism of Wolbachia-mediated virus inhibition. We demonstrate that, contrary to previous suggestions, there is no association between a strain's ability to inhibit dengue infection in the mosquito and either its typical density in the midgut or salivary glands, or the degree to which it elevates innate immune response pathways in the mosquito. These findings, and the experimental platform provided by this panel of genetically comparable mosquito lines, clear the way for future investigations to define how Wolbachia prevents Ae. aegypti from transmitting viruses.


Assuntos
Aedes/microbiologia , Vírus da Dengue , Interações Microbianas/fisiologia , Mosquitos Vetores/microbiologia , Wolbachia , Animais , Dengue/prevenção & controle , Dengue/transmissão , Infecções por Bactérias Gram-Negativas , Controle Biológico de Vetores/métodos , Fenótipo
4.
PLoS Pathog ; 16(4): e1008433, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32282862

RESUMO

The insect bacterium Wolbachia pipientis is being introgressed into Aedes aegypti populations as an intervention against the transmission of medically important arboviruses. Here we compare Ae. aegypti mosquitoes infected with wMelCS or wAlbB to the widely used wMel Wolbachia strain on an Australian nuclear genetic background for their susceptibility to infection by dengue virus (DENV) genotypes spanning all four serotypes. All Wolbachia-infected mosquitoes were more resistant to intrathoracic DENV challenge than their wildtype counterparts. Blocking of DENV replication was greatest by wMelCS. Conversely, wAlbB-infected mosquitoes were more susceptible to whole body infection than wMel and wMelCS. We extended these findings via mosquito oral feeding experiments, using viremic blood from 36 acute, hospitalised dengue cases in Vietnam, additionally including wMel and wildtype mosquitoes on a Vietnamese nuclear genetic background. As above, wAlbB was less effective at blocking DENV replication in the abdomen compared to wMel and wMelCS. The transmission potential of all Wolbachia-infected mosquito lines (measured by the presence/absence of infectious DENV in mosquito saliva) after 14 days, was significantly reduced compared to their wildtype counterparts, and lowest for wMelCS and wAlbB. These data support the use of wAlbB and wMelCS strains for introgression field trials and the biocontrol of DENV transmission. Furthermore, despite observing significant differences in transmission potential between wildtype mosquitoes from Australia and Vietnam, no difference was observed between wMel-infected mosquitoes from each background suggesting that Wolbachia may override any underlying variation in DENV transmission potential.


Assuntos
Aedes/microbiologia , Aedes/virologia , Vírus da Dengue/fisiologia , Mosquitos Vetores/microbiologia , Mosquitos Vetores/virologia , Wolbachia/fisiologia , Aedes/genética , Aedes/metabolismo , Animais , Feminino , Masculino , Mosquitos Vetores/genética , Mosquitos Vetores/metabolismo , Controle Biológico de Vetores , Replicação Viral
5.
Pharm Res ; 38(8): 1387-1395, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34382142

RESUMO

PURPOSE: To evaluate the physical and chemical degradation of monoclonal antibodies in the presence of Zn2+. METHODS: A full length IgG1 monoclonal antibody (mAb1) was formulated with various amounts of Zn2+. The resulting mixture was incubated for several weeks at room temperature and analyzed using a variety of biochemical techniques to look for various physical (e.g. aggregation) and chemical (e.g. fragmentation) degradation pathways. RESULTS: mAb1 of the IgG1 subclass undergoes aggregation in the presence of Zn2+ in a concentration dependent manner. Up to hexamers were characterized using SEC-MALS. No fragmentation was noticed in the presence of Zn2+ as opposed to that found in our previous report when IgG1 mAbs were incubated in the presence of Cu2+ ions. Site directed mutagenesis indicated the involvement of Fc histidine (His 310) in Zn2+ mediated aggregation. CONCLUSIONS: A novel metal ion mediated isodesmic aggregation mechanism was found in IgG1 class of monoclonal antibodies. Histidine residues in the Fc region were determined to be the binding site and implicated in Zn2+ mediated aggregation.


Assuntos
Anticorpos Monoclonais/química , Imunoglobulina G/química , Agregados Proteicos , Zinco/química , Sítios de Ligação de Anticorpos , Cobre/química , Multimerização Proteica , Viscosidade
6.
PLoS Pathog ; 13(12): e1006751, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29216317

RESUMO

Wolbachia pipientis from Drosophila melanogaster (wMel) is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster), wRi (D. simulans) and wPip (Culex quinquefasciatus) and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing.


Assuntos
Aedes/microbiologia , Transmissão Vertical de Doenças Infecciosas/veterinária , Mosquitos Vetores/microbiologia , Wolbachia/crescimento & desenvolvimento , Aedes/crescimento & desenvolvimento , Aedes/fisiologia , Aedes/virologia , Animais , Controle de Doenças Transmissíveis/métodos , Culex/microbiologia , Vírus da Dengue/isolamento & purificação , Vírus da Dengue/fisiologia , Drosophila melanogaster/microbiologia , Drosophila simulans/microbiologia , Feminino , Fertilidade , Masculino , Controle de Mosquitos/métodos , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Especificidade de Órgãos , Ovário/microbiologia , Ovário/fisiologia , RNA Viral/isolamento & purificação , Glândulas Salivares/microbiologia , Glândulas Salivares/fisiologia , Caracteres Sexuais , Especificidade da Espécie , Análise de Sobrevida , Tropismo Viral , Wolbachia/isolamento & purificação
7.
PLoS Genet ; 11(8): e1005453, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26291077

RESUMO

Many reproductive proteins from diverse taxa evolve rapidly and adaptively. These proteins are typically involved in late stages of reproduction such as sperm development and fertilization, and are more often functional in males than females. Surprisingly, many germline stem cell (GSC) regulatory genes, which are essential for the earliest stages of reproduction, also evolve adaptively in Drosophila. One example is the bag of marbles (bam) gene, which is required for GSC differentiation and germline cyst development in females and for regulating mitotic divisions and entry to spermatocyte differentiation in males. Here we show that the extensive divergence of bam between Drosophila melanogaster and D. simulans affects bam function in females but has no apparent effect in males. We further find that infection with Wolbachia pipientis, an endosymbiotic bacterium that can affect host reproduction through various mechanisms, partially suppresses female sterility caused by bam mutations in D. melanogaster and interacts differentially with bam orthologs from D. melanogaster and D. simulans. We propose that the adaptive evolution of bam has been driven at least in part by the long-term interactions between Drosophila species and Wolbachia. More generally, we suggest that microbial infections of the germline may explain the unexpected pattern of evolution of several GSC regulatory genes.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/metabolismo , Wolbachia/fisiologia , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/microbiologia , Evolução Molecular , Feminino , Expressão Gênica , Teste de Complementação Genética , Interações Hospedeiro-Patógeno , Infertilidade/genética , Masculino , Ovário/metabolismo , Ovário/patologia , Caracteres Sexuais
8.
Proc Natl Acad Sci U S A ; 112(18): 5679-84, 2015 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-25902490

RESUMO

TNF superfamily death ligands are expressed on the surface of immune cells and can trigger apoptosis in susceptible cancer cells by engaging cognate death receptors. A recombinant soluble protein comprising the ectodomain of Apo2 ligand/TNF-related apoptosis-inducing ligand (Apo2L/TRAIL) has shown remarkable preclinical anticancer activity but lacked broad efficacy in patients, possibly owing to insufficient exposure or potency. We observed that antibody cross-linking substantially enhanced cytotoxicity of soluble Apo2L/TRAIL against diverse cancer cell lines. Presentation of the ligand on glass-supported lipid bilayers enhanced its ability to drive receptor microclustering and apoptotic signaling. Furthermore, covalent surface attachment of Apo2L/TRAIL onto liposomes--synthetic lipid-bilayer nanospheres--similarly augmented activity. In vivo, liposome-displayed Apo2L/TRAIL achieved markedly better exposure and antitumor activity. Thus, covalent synthetic-membrane attachment of a cell-surface ligand enhances efficacy, increasing therapeutic potential. These findings have translational implications for liposomal approaches as well as for Apo2L/TRAIL and other clinically relevant TNF ligands.


Assuntos
Antineoplásicos/química , Membrana Celular/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Animais , Apoptose , Biotinilação , Ligante CD27/metabolismo , Caspase 8/metabolismo , Caspases/metabolismo , Linhagem Celular Tumoral , Epitopos/química , Proteína Ligante Fas/metabolismo , Humanos , Sistema Imunitário , Imunoterapia/métodos , Concentração Inibidora 50 , Ligantes , Lipossomos/química , Camundongos , Camundongos Nus , Microscopia de Fluorescência , Transplante de Neoplasias , Neoplasias/imunologia , Neoplasias/metabolismo , Proteínas Recombinantes/metabolismo
10.
J Invertebr Pathol ; 143: 18-25, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27871813

RESUMO

Animals experience near constant infection with microorganisms. A significant proportion of these microbiota reside in the alimentary tract. There is a growing appreciation for the roles gut microbiota play in host biology. The gut microbiota of insects, for example, have been shown to help the host overcome pathogen infection either through direct competition or indirectly by stimulating host immunity. These defenses may also be supplemented by coinfecting maternally inherited microbes such as Wolbachia. The presence of Wolbachia in a host can delay and/or reduce death caused by RNA viruses. Whether the gut microbiota of the host interacts with Wolbachia, or vice versa, the precise role of Wolbachia in antiviral protection is not known. In this study, we used 16S rDNA sequencing to characterise changes in gut microbiota composition in Drosophila melanogaster associated with Wolbachia infection and antibiotic treatment. We subsequently tested whether changes in gut composition via antibiotic treatment altered Wolbachia-mediated antiviral properties. We found that both antibiotics and Wolbachia significantly reduced the biodiversity of the gut microbiota without changing the total microbial load. We also showed that changing the gut microbiota composition with antibiotic treatment enhanced Wolbachia density but did not confer greater antiviral protection against Drosophila C virus to the host. We concluded there are significant interactions between Wolbachia and gut microbiota, but changing gut microbiota composition is not likely to be a means through which Wolbachia conveys antiviral protection to its host.


Assuntos
Drosophila melanogaster/microbiologia , Microbioma Gastrointestinal , Interações Hospedeiro-Patógeno , Viroses/microbiologia , Wolbachia , Animais , Antibacterianos/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Vírus de Insetos , Vírus de RNA
11.
mBio ; 15(2): e0249523, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38132636

RESUMO

Wolbachia are a genus of insect endosymbiotic bacteria which includes strains wMel and wAlbB that are being utilized as a biocontrol tool to reduce the incidence of Aedes aegypti-transmitted viral diseases like dengue. However, the precise mechanisms underpinning the antiviral activity of these Wolbachia strains are not well defined. Here, we generated a panel of Ae. aegypti-derived cell lines infected with antiviral strains wMel and wAlbB or the non-antiviral Wolbachia strain wPip to understand host cell morphological changes specifically induced by antiviral strains. Antiviral strains were frequently found to be entirely wrapped by the host endoplasmic reticulum (ER) membrane, while wPip bacteria clustered separately in the host cell cytoplasm. ER-derived lipid droplets (LDs) increased in volume in wMel- and wAlbB-infected cell lines and mosquito tissues compared to cells infected with wPip or Wolbachia-free controls. Inhibition of fatty acid synthase (required for triacylglycerol biosynthesis) reduced LD formation and significantly restored ER-associated dengue virus replication in cells occupied by wMel. Together, this suggests that antiviral Wolbachia strains may specifically alter the lipid composition of the ER to preclude the establishment of dengue virus (DENV) replication complexes. Defining Wolbachia's antiviral mechanisms will support the application and longevity of this effective biocontrol tool that is already being used at scale.IMPORTANCEAedes aegypti transmits a range of important human pathogenic viruses like dengue. However, infection of Ae. aegypti with the insect endosymbiotic bacterium, Wolbachia, reduces the risk of mosquito to human viral transmission. Wolbachia is being utilized at field sites across more than 13 countries to reduce the incidence of viruses like dengue, but it is not well understood how Wolbachia induces its antiviral effects. To examine this at the subcellular level, we compared how different strains of Wolbachia with varying antiviral strengths associate with and modify host cell structures. Strongly antiviral strains were found to specifically associate with the host endoplasmic reticulum and induce striking impacts on host cell lipid droplets. Inhibiting Wolbachia-induced lipid redistribution partially restored dengue virus replication demonstrating this is a contributing role for Wolbachia's antiviral activity. These findings provide new insights into how antiviral Wolbachia strains associate with and modify Ae. aegypti host cells.


Assuntos
Aedes , Vírus da Dengue , Dengue , Wolbachia , Animais , Humanos , Vírus da Dengue/fisiologia , Wolbachia/fisiologia , Gotículas Lipídicas , Replicação Viral , Retículo Endoplasmático , Antivirais , Lipídeos
12.
PLoS Negl Trop Dis ; 18(3): e0012022, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38484041

RESUMO

Pacific Island countries have experienced periodic dengue, chikungunya and Zika outbreaks for decades. The prevention and control of these mosquito-borne diseases rely heavily on control of Aedes aegypti mosquitoes, which in most settings are the primary vector. Introgression of the intracellular bacterium Wolbachia pipientis (wMel strain) into Ae. aegypti populations reduces their vector competence and consequently lowers dengue incidence in the human population. Here we describe successful area-wide deployments of wMel-infected Ae. aegypti in Suva, Lautoka, Nadi (Fiji), Port Vila (Vanuatu) and South Tarawa (Kiribati). With community support, weekly releases of wMel-infected Ae. aegypti mosquitoes for between 2 to 5 months resulted in wMel introgression in nearly all locations. Long term monitoring confirmed a high, self-sustaining prevalence of wMel infecting mosquitoes in almost all deployment areas. Measurement of public health outcomes were disrupted by the Covid19 pandemic but are expected to emerge in the coming years.


Assuntos
Aedes , Vírus da Dengue , Dengue , Wolbachia , Infecção por Zika virus , Zika virus , Animais , Humanos , Aedes/genética , Aedes/microbiologia , Mosquitos Vetores/genética , Mosquitos Vetores/microbiologia , Wolbachia/genética , Fiji/epidemiologia , Vanuatu
13.
Bioconjug Chem ; 24(10): 1674-83, 2013 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-24070051

RESUMO

Conjugation of an antibody to a drug can produce heterogeneous species that may have different physical stabilities and safety profiles. We explored the effect of thermal stress on the physical stability, specifically aggregation, of an antibody drug conjugate (ADC), ADC 1, wherein the antibody was linked to the val-cit-Monomethyl Auristatin E (vc-MMAE) linker drug through the reduction of interchain disulfides. We also explored the effects of conjugation on the secondary and tertiary structures of ADC 1. Circular dichroism, intrinsic tryptophan fluorescence, and differential scanning calorimetry showed that for species with high drug loading, conjugation does not measurably alter the secondary structure, but it does render the CH2 domain less stable to thermal stress such that ADC 1 rapidly forms high molecular weight species (HMWS) at 40 °C. Characterization of the HMWS using chromatographic and electrophoretic methods showed that it is an irreversible, noncovalent, and structurally altered form of ADC 1 primarily composed of molecules with six or eight drugs. Furthermore, the variable domain of the antibody may contribute to the extent of aggregation, since eight ADCs with over 90% sequence homology exhibited monthly rates of HMWS formation that differ by up to a factor of 2.


Assuntos
Anticorpos Monoclonais Humanizados/química , Imunoconjugados/química , Imunoglobulina G/química , Oligopeptídeos/química , Dissulfetos/química , Humanos , Estabilidade Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Temperatura
14.
Psychol Serv ; 20(3): 506-515, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35254845

RESUMO

Trauma-focused treatments for posttraumatic stress disorder (PTSD), such as Prolonged Exposure (PE) therapy and Cognitive Processing Therapy (CPT), are effective and supported by various Clinical Practice Guidelines; however, drop-out rates for the treatments are as high as 40% within clinical programs. One promising solution is delivering the evidence-based psychotherapies (EBPs) three or more times per week within an intensive outpatient program (IOP) for PTSD. The present study examined the feasibility and effectiveness of a relatively low-resourced PTSD IOP within a larger PTSD program at the Veterans Healthcare Administration. The intensive program offers two tracks (2 week or 4 week) grounded in the massed delivery of PE and CPT. Over a 12-month period, 351 veterans completed an assessment for PTSD and 172 started within one of the local PTSD programs (e.g., weekly, IOP, or residential). Results of the study demonstrated that the IOP is an acceptable (i.e., 87.3% completion rate) and effective (e.g., PTSD Checklist for Diagnostic and Statistical Manual [DSM-5] [PCL-5] decrease effect size d = 1.80) treatment option. There was also adequate demand for the program (e.g., 37.2% of patients engaged in care with the PTSD programs started the IOP), and the program was implemented with fidelity to the design. Taken together, the results of this study demonstrate that this low-resource IOP model is a promising approach to improve completion rates within the continuum of care for the treatment of PTSD. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Assuntos
Terapia Cognitivo-Comportamental , Transtornos de Estresse Pós-Traumáticos , Veteranos , Humanos , Veteranos/psicologia , Transtornos de Estresse Pós-Traumáticos/terapia , Transtornos de Estresse Pós-Traumáticos/psicologia , Terapia Cognitivo-Comportamental/métodos , Pacientes Ambulatoriais , Estudos de Viabilidade , Saúde dos Veteranos
15.
Parasit Vectors ; 16(1): 108, 2023 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-36934294

RESUMO

BACKGROUND: Introgression of the bacterial endosymbiont Wolbachia into Aedes aegypti populations is a biocontrol approach being used to reduce arbovirus transmission. This requires mass release of Wolbachia-infected mosquitoes. While releases have been conducted using a variety of techniques, egg releases, using water-soluble capsules containing mosquito eggs and larval food, offer an attractive method due to its potential to reduce onsite resource requirements. However, optimisation of this approach is required to ensure there is no detrimental impact on mosquito fitness and to promote successful Wolbachia introgression. METHODS: We determined the impact of storage time and temperature on wild-type (WT) and Wolbachia-infected (wMel or wAlbB strains) Ae. aegypti eggs. Eggs were stored inside capsules over 8 weeks at 18 °C or 22 °C and hatch rate, emergence rate and Wolbachia density were determined. We next examined egg quality and Wolbachia density after exposing eggs to 4-40 °C to determine how eggs may be impacted if exposed to extreme temperatures during shipment. RESULTS: Encapsulating eggs for 8 weeks did not negatively impact egg viability or resulting adult emergence and Wolbachia density compared to controls. When eggs were exposed to temperatures within 4-36 °C for 48 h, their viability and resulting adult Wolbachia density were maintained; however, both were significantly reduced when exposed to 40 °C. CONCLUSIONS: We describe the time and temperature limits for maintaining viability of Wolbachia-infected Ae. aegypti eggs when encapsulated or exposed to extreme temperatures. These findings could improve the efficiency of mass releases by providing transport and storage constraints to ensure only high-quality material is utilised during field releases.


Assuntos
Aedes , Wolbachia , Animais , Temperatura , Mosquitos Vetores , Ovos
16.
Virus Evol ; 9(1): vead016, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37744653

RESUMO

The introgression of antiviral strains of Wolbachia into Aedes aegypti mosquito populations is a public health intervention for the control of dengue. Plausibly, dengue virus (DENV) could evolve to bypass the antiviral effects of Wolbachia and undermine this approach. Here, we established a serial-passage system to investigate the evolution of DENV in Ae. aegypti mosquitoes infected with the wMel strain of Wolbachia. Using this system, we report on virus genetic outcomes after twenty passages of serotype 1 of DENV (DENV-1). An amino acid substitution, E203K, in the DENV-1 envelope protein was more frequently detected in the consensus sequence of virus populations passaged in wMel-infected Ae. aegypti than wild-type counterparts. Positive selection at residue 203 was reproducible; it occurred in passaged virus populations from independent DENV-1-infected patients and also in a second, independent experimental system. In wild-type mosquitoes and human cells, the 203K variant was rapidly replaced by the progenitor sequence. These findings provide proof of concept that wMel-associated selection of virus populations can occur in experimental conditions. Field-based studies are needed to explore whether wMel imparts selective pressure on DENV evolution in locations where wMel is established.

17.
Pathogens ; 11(3)2022 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-35335697

RESUMO

Release and subsequent establishment of Wolbachia-infected Aedes aegypti in native mosquito populations has successfully reduced mosquito-borne disease incidence. While this is promising, further development is required to ensure that this method is scalable and sustainable. Egg release is a beneficial technique that requires reduced onsite resources and increases community acceptance; however, its incidental ecological impacts must be considered to ensure sustainability. In this study, we tested a more environmentally friendly mosquito rearing and release approach through the encapsulation of diet and egg mixtures and the subsequent utilization of waste containers to hatch and release mosquitoes. An ecologically friendly diet mix was specifically developed and tested for use in capsules, and we demonstrated that using either cricket or black soldier fly meal as a substitute for beef liver powder had no adverse effects on fitness or Wolbachia density. We further encapsulated both the egg and diet mixes and demonstrated no loss in viability. To address the potential of increased waste generation through disposable mosquito release containers, we tested reusing commonly found waste containers (aluminum and tin cans, PET, and glass bottles) as an alternative, conducting a case study in Kiribati to assess the concept's cultural, political, and economic applicability. Our results showed that mosquito emergence and fitness was maintained with a variety of containers, including when tested in the field, compared to control containers, and that there are opportunities to implement this method in the Pacific Islands in a way that is culturally considerate and cost-effective.

18.
Pathogens ; 11(5)2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35631057

RESUMO

Wolbachia is an endosymbiotic bacterium that can restrict the transmission of human pathogenic viruses by Aedes aegypti mosquitoes. Recent field trials have shown that dengue incidence is significantly reduced when Wolbachia is introgressed into the local Ae. aegypti population. Female Ae. aegypti are anautogenous and feed on human blood to produce viable eggs. Herein, we tested whether people who reside on Tri Nguyen Island (TNI), Vietnam developed antibodies to Wolbachia Surface Protein (WSP) following release of Wolbachia-infected Ae. aegypti, as a measure of exposure to Wolbachia. Paired blood samples were collected from 105 participants before and after mosquito releases and anti-WSP titres were measured by ELISA. We determined no change in anti-WSP titres after ~30 weeks of high levels of Wolbachia-Ae. aegypti on TNI. These data suggest that humans are not exposed to the major Wolbachia surface antigen, WSP, following introgression of Wolbachia-infected Ae. aegypti mosquitoes.

19.
Microb Genom ; 7(9)2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34468309

RESUMO

Infection of wMel Wolbachia in Aedes aegypti imparts two signature features that enable its application for biocontrol of dengue. First, the susceptibility of mosquitoes to viruses such as dengue and Zika is reduced. Second, a reproductive manipulation is caused that enables wMel introgression into wild-type mosquito populations. The long-term success of this method relies, in part, on evolution of the wMel genome not compromising the critical features that make it an attractive biocontrol tool. This study compared the wMel Wolbachia genome at the time of initial releases and 1-7 years post-release in Cairns, Australia. Our results show the wMel genome remains highly conserved up to 7 years post-release in gene sequence, content, synteny and structure. This work suggests the wMel genome is stable in its new mosquito host and, therefore, provides reassurance on the potential for wMel to deliver long-term public-health impacts.


Assuntos
Aedes/microbiologia , Genoma Bacteriano , Wolbachia/genética , Aedes/virologia , Animais , Austrália , Dengue , Vírus da Dengue , Evolução Molecular , Zika virus , Infecção por Zika virus
20.
PLoS Negl Trop Dis ; 15(9): e0009752, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34492017

RESUMO

BACKGROUND: Biological control programs involving Wolbachia-infected Aedes aegypti are currently deployed in different epidemiological settings. New Caledonia (NC) is an ideal location for the implementation and evaluation of such a strategy as the only proven vector for dengue virus (DENV) is Ae. aegypti and dengue outbreaks frequency and severity are increasing. We report the generation of a NC Wolbachia-infected Ae. aegypti strain and the results of experiments to assess the vector competence and fitness of this strain for future implementation as a disease control strategy in Noumea, NC. METHODS/PRINCIPAL FINDINGS: The NC Wolbachia strain (NC-wMel) was obtained by backcrossing Australian AUS-wMel females with New Caledonian Wild-Type (NC-WT) males. Blocking of DENV, chikungunya (CHIKV), and Zika (ZIKV) viruses were evaluated via mosquito oral feeding experiments and intrathoracic DENV challenge. Significant reduction in infection rates were observed for NC-wMel Ae. aegypti compared to WT Ae. aegypti. No transmission was observed for NC-wMel Ae. aegypti. Maternal transmission, cytoplasmic incompatibility, fertility, fecundity, wing length, and insecticide resistance were also assessed in laboratory experiments. Ae. aegypti NC-wMel showed complete cytoplasmic incompatibility and a strong maternal transmission. Ae. aegypti NC-wMel fitness seemed to be reduced compared to NC-WT Ae. aegypti and AUS-wMel Ae. aegypti regarding fertility and fecundity. However further experiments are required to assess it accurately. CONCLUSIONS/SIGNIFICANCE: Our results demonstrated that the NC-wMel Ae. aegypti strain is a strong inhibitor of DENV, CHIKV, and ZIKV infection and prevents transmission of infectious viral particles in mosquito saliva. Furthermore, our NC-wMel Ae. aegypti strain induces reproductive cytoplasmic incompatibility with minimal apparent fitness costs and high maternal transmission, supporting field-releases in Noumea, NC.


Assuntos
Aedes/microbiologia , Controle de Mosquitos/métodos , Mosquitos Vetores/microbiologia , Controle Biológico de Vetores/métodos , Wolbachia , Animais , Vírus Chikungunya/fisiologia , Vírus da Dengue/classificação , Vírus da Dengue/fisiologia , Nova Caledônia , Zika virus/classificação
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