Aedes aegypti: egg morphology and embryonic development

Abstract Background The diseases for which Aedes aegypti is a vector are worrisome. The high vector competence of this mosquito, as well as its anthropophilia and ability to adapt to the urban environment, allows it to exploit many habitats, making its prevention an arduous task. Despite current disease control measures focused on the mosquito, the effectiveness in containing its dispersion still requires improvement; thus greater knowledge about this insect is fundamental. Methods Aedes aegypti egg morphology and embryonic development were analyzed from eggs of the insectary of the Institute of Biomedical Sciences of the University of São Paulo. Optical (light and confocal) and electronic (transmission and scanning) microscopy were used to analyze the morphological and ultrastructural features of the eggs. Embryos were observed in the initial (0–20.5 h after egg-laying), intermediate (20.6–40.1 h after egg-laying), and final (40.2–61.6 h) stages of development, and kept at a temperature of 28 °C ± 1 °C until collection for processing. Results Eggs of Ae. aegypti were whitish at the time of oviposition, and then quickly became black. The egg length was 581.45 ± 39.73 μm and the width was 175.36 ± 11.59. Access to the embryo was difficult due to the egg morphology, point of embryonic development, and difficult permeability of the exochorion (mainly in fixation). Only about 5% of the collected eggs were successfully processed. In the initial stage of embryonic development, characteristics suggestive of intense cellular activity were found. In the intermediate stage, the beginning of the segmentation process was evident. In the final phase, it was possible to differentiate the cephalic region and the thoracic and abdominal segments. Conclusion The chorion was found to be an important protective barrier and a limiting factor for the evaluation of the embryos and mosquito embryonic cells, indicating that further studies need to be carried out to identify the reason that this occurs. Graphical abstract

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Aedes Aegypti: Morphology the Egg and Embryonic Development

10.21203/rs.3.rs-274534/v1 ◽

2021 ◽

Author(s):

Ana Paula Miranda Mundim-Pombo ◽

Marisol León ◽

Hianka Jasmyne Costa de Carvalho ◽

Durvanei Augusto Maria ◽

Maria Angelica Miglino

Keyword(s):

Embryonic Development ◽

Aedes Aegypti ◽

Morphological Characteristics ◽

Microscopic Analysis ◽

Biomedical Sciences ◽

Great Resistance ◽

Egg Morphology ◽

Great Relevance ◽

Control Technologies ◽

The University

Abstract Background: Aedes aegypti (Diptera: Culicidae) has great relevance in public health worldwide due to its performance as a vector of arboviruses, which makes the knowledge about its cycle fundamental. It is known that the acquaintance of embryonic kinetics has great potential to assist in the development of new vector control technologies and, consequently, in the control of arboviruses. Methods: This research proposes to analyze the egg morphology and embryonic development of Aedes aegypti. Eggs from the insectary of the Institute of Biomedical Sciences of the University of São Paulo (n = 46) were used. The methodological procedure involved morphological and ultrastructural analyzes using equipment for optical microscopy (light and confocal) and electronic (scanning). Eggs and embryos were observed in initial, intermediate and final thirds of development, kept at a temperature of 28°C, 1°C until collection for processing. Results: The embryos had different morphological characteristics according to the stage of gestation, in the initial and intermediate stages of development. In the initial third, the presence of primordial epithelium and characteristics suggestive of intense cellular activity were found. Conclusion: According to the results obtained in the eggs, it is concluded that the great resistance of the chorion in the embryo is a factor that generates difficulties for microscopic analysis of the embryo (mainly in fixation), with a strong protective barrier.

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Quiescence in Aedes aegypti: Interpopulation Differences Contribute to Population Dynamics and Vectorial Capacity

Insects ◽

10.3390/insects9030111 ◽

2018 ◽

Vol 9 (3) ◽

pp. 111 ◽

Cited By ~ 4

Author(s):

Luciana Oliva ◽

Roseli La Corte ◽

Marcelo Santana ◽

Cleide Albuquerque

Keyword(s):

Population Dynamics ◽

Embryonic Development ◽

Aedes Aegypti ◽

Development Time ◽

Mosquito Species ◽

Vectorial Capacity ◽

Control Measures ◽

Adult Size ◽

Egg Viability ◽

Male Predominance

The strategy of Aedes aegypti to prolong embryonic viability by quiescence has severe implications for geographic expansion and maintenance of mosquito populations in areas under control measures. We evaluated the effects of quiescence on biological parameters directly or indirectly associated with population dynamics and vectorial capacity in populations of this mosquito species from two Brazilian municipalities characterized as dengue, chikungunya, and Zika transmission areas. Egg viability, initial hatching time, post-embryonic development time, adult emergence rate, sexual proportion, adult size, fecundity, and fertility were analyzed using eggs stored for 10, 40, 70, 100, 130, and 160 d. Quiescence time reduced overall egg viability and post-embryonic development time in both municipalities but was more costly in Aracaju (100 d, 8 d) than in Recife (130 d, 7.5 d). Emergence rates increased in Recife when the eggs were older, but not in Aracaju. Significant deviations in sexual proportion, with male predominance, were observed in both populations. Initial hatch, fecundity, fertility, and adult size did not significantly influence egg quiescence time. These results indicate intrinsic and differential characteristics for each A. aegypti population, suggesting a differential cost of quiescence for population dynamics parameters that can indirectly affect vectorial capacity and control measures.

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Notes on Culicine Mosquitos in Tanganyika Territory

Bulletin of Entomological Research ◽

10.1017/s000748530002647x ◽

1942 ◽

Vol 33 (3) ◽

pp. 181-193 ◽

Cited By ~ 17

Author(s):

W. Victor Harris

Keyword(s):

Aedes Aegypti ◽

Dar Es Salaam ◽

Fixed Number ◽

Egg Laying ◽

Control Measures ◽

Actual Process ◽

Rural Districts ◽

Tree Holes ◽

Constant Period ◽

Domestic Breeding

The examination of mosquito larvae collected by house searchers on Stegomyia control measures in Dar-es-Salaam, the largest town in Tanganyika, shows that Aëdes aegypti is definitely the predominant domestic breeder there. The other species of the genus Aëdes encountered are listed with their frequencies.Similarly the examination of larvae found in tree-holes in Dar-es-Salaam shows that Aëdes aegypti, A. simpsoni and A. metallicus are regularly encountered.A system of obtaining an index of the population density of both A. aegypti and A. simpsoni, unconnected with the actual process of Stegomyia control measures, is described. This would be applicable to smaller towns, rural districts, and towns in high rainfall areas where A. aegypti is not the only danger as a yellow fever vector, and where extra-domestic breeding is important. The system is based on the exposure of a fixed number of bamboo pots containing water for a constant period of days, to attract egg-laying female mosquitos. Species of mosquitos and their frequencies obtained in a series of trials are given.

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Improved Aedes aegypti mosquito reference genome assembly enables biological discovery and vector control

10.1101/240747 ◽

2017 ◽

Cited By ~ 7

Author(s):

Benjamin J. Matthews ◽

Olga Dudchenko ◽

Sarah Kingan ◽

Sergey Koren ◽

Igor Antoshechkin ◽

...

Keyword(s):

Aedes Aegypti ◽

Insecticide Resistance ◽

Genome Assembly ◽

Vector Competence ◽

Egg Laying ◽

Glutathione S Transferase ◽

Viral Pathogens ◽

Biological Discovery ◽

And Control ◽

High Quality Genome

Female Aedes aegypti mosquitoes infect hundreds of millions of people each year with dangerous viral pathogens including dengue, yellow fever, Zika, and chikungunya. Progress in understanding the biology of this insect, and developing tools to fight it, has been slowed by the lack of a high-quality genome assembly. Here we combine diverse genome technologies to produce AaegL5, a dramatically improved and annotated assembly, and demonstrate how it accelerates mosquito science and control. We anchored the physical and cytogenetic maps, resolved the size and composition of the elusive sex-determining “M locus”, significantly increased the known members of the glutathione-S-transferase genes important for insecticide resistance, and doubled the number of chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites. Using high-resolution QTL and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. We predict that AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly arboviral vector.

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Vector Competence of Aedes aegypti, Aedes albopictus and Culex quinquefasciatus from Brazil and New Caledonia for Three Zika Virus Lineages

Pathogens ◽

10.3390/pathogens9070575 ◽

2020 ◽

Vol 9 (7) ◽

pp. 575 ◽

Cited By ~ 2

Author(s):

Rosilainy S. Fernandes ◽

Olivia O’Connor ◽

Maria Ignez L. Bersot ◽

Dominique Girault ◽

Marguerite R. Dokunengo ◽

...

Keyword(s):

Aedes Aegypti ◽

Culex Quinquefasciatus ◽

Zika Virus ◽

Mosquito Control ◽

New Caledonia ◽

Vector Competence ◽

Control Measures ◽

The Pacific ◽

Viral Surveillance ◽

Virus Strains

Zika virus (ZIKV) has caused severe epidemics in South America beginning in 2015, following its spread through the Pacific. We comparatively assessed the vector competence of ten populations of Aedes aegypti and Ae. albopictus from Brazil and two of Ae. aegypti and one of Culex quinquefasciatus from New Caledonia to transmit three ZIKV isolates belonging to African, Asian and American lineages. Recently colonized mosquitoes from eight distinct sites from both countries were orally challenged with the same viral load (107 TCID50/mL) and examined after 7, 14 and 21 days. Cx. quinquefasciatus was refractory to infection with all virus strains. In contrast, although competence varied with geographical origin, Brazilian and New Caledonian Ae. aegypti could transmit the three ZIKV lineages, with a strong advantage for the African lineage (the only one reaching saliva one-week after challenge). Brazilian Ae. albopictus populations were less competent than Ae. aegypti populations. Ae. albopictus generally exhibited almost no transmission for Asian and American lineages, but was efficient in transmitting the African ZIKV. Viral surveillance and mosquito control measures must be strengthened to avoid the spread of new ZIKV lineages and minimize the transmission of viruses currently circulating.

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Faculty Opinions recommendation of The ion channel ppk301 controls freshwater egg-laying in the mosquito Aedes aegypti.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.735802738.793568235 ◽

2019 ◽

Author(s):

Thomas Finger

Keyword(s):

Aedes Aegypti ◽

Ion Channel ◽

Egg Laying

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Internal embryonic development in a non-copulatory, egg-laying teleost, the three-spined stickleback, Gasterosteus aculeatus

Scientific Reports ◽

10.1038/s41598-019-38584-w ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Laura L. Dean ◽

Shaun Robertson ◽

Muayad Mahmud ◽

Andrew D. C. MacColl

Keyword(s):

Embryonic Development ◽

Gasterosteus Aculeatus ◽

Egg Laying

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Microbiome-based environmental monitoring of a dairy processing facility highlights the challenges associated with low microbial-load samples

npj Science of Food ◽

10.1038/s41538-021-00087-2 ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Aoife J. McHugh ◽

Min Yap ◽

Fiona Crispie ◽

Conor Feehily ◽

Colin Hill ◽

...

Keyword(s):

Environmental Monitoring ◽

Illumina Sequencing ◽

Food Chain ◽

Control Measures ◽

Initial Assessment ◽

Limiting Factor ◽

Accurate Identification ◽

Processing Facility ◽

High Concentrations ◽

Sequencing Platforms

AbstractEfficient and accurate identification of microorganisms throughout the food chain can potentially allow the identification of sources of contamination and the timely implementation of control measures. High throughput DNA sequencing represents a potential means through which microbial monitoring can be enhanced. While Illumina sequencing platforms are most typically used, newer portable platforms, such as the Oxford Nanopore Technologies (ONT) MinION, offer the potential for rapid analysis of food chain microbiomes. Initial assessment of the ability of rapid MinION-based sequencing to identify microbes within a simple mock metagenomic mixture is performed. Subsequently, we compare the performance of both ONT and Illumina sequencing for environmental monitoring of an active food processing facility. Overall, ONT MinION sequencing provides accurate classification to species level, comparable to Illumina-derived outputs. However, while the MinION-based approach provides a means of easy library preparations and portability, the high concentrations of DNA needed is a limiting factor.

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Permethrin Resistance in Aedes aegypti Affects Aspects of Vectorial Capacity

Insects ◽

10.3390/insects12010071 ◽

2021 ◽

Vol 12 (1) ◽

pp. 71

Author(s):

Tse-Yu Chen ◽

Chelsea T. Smartt ◽

Dongyoung Shin

Keyword(s):

Aedes Aegypti ◽

Sodium Channel ◽

Mosquito Control ◽

Vector Competence ◽

Vectorial Capacity ◽

Parental Population ◽

Control Programs ◽

Channel Gene ◽

Sodium Channel Gene ◽

Specific Pcr

Aedes aegypti, as one of the vectors transmitting several arboviruses, is the main target in mosquito control programs. Permethrin is used to control mosquitoes and Aedes aegypti get exposed due to its overuse and are now resistant. The increasing percentage of permethrin resistant Aedes aegypti has become an important issue around the world and the potential influence on vectorial capacity needs to be studied. Here we selected a permethrin resistant (p-s) Aedes aegypti population from a wild Florida population and confirmed the resistance ratio to its parental population. We used allele-specific PCR genotyping of the V1016I and F1534C sites in the sodium channel gene to map mutations responsible for the resistance. Two important factors, survival rate and vector competence, that impact vectorial capacity were checked. Results indicated the p-s population had 20 times more resistance to permethrin based on LD50 compared to the parental population. In the genotyping study, the p-s population had more homozygous mutations in both mutant sites of the sodium channel gene. The p-s adults survived longer and had a higher dissemination rate for dengue virus than the parental population. These results suggest that highly permethrin resistant Aedes aegypti populations might affect the vectorial capacity, moreover, resistance increased the survival time and vector competence, which should be of concern in areas where permethrin is applied.

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