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

2017 ◽  
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.

scholarly journals Aedes aegypti: egg morphology and embryonic development

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ana Paula Miranda Mundim-Pombo ◽  
Hianka Jasmyne Costa de Carvalho ◽  
Rafaela Rodrigues Ribeiro ◽  
Marisol León ◽  
Durvanei Augusto Maria ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Aedes Aegypti ◽  
Vector Competence ◽  
Intermediate Stage ◽  
Egg Laying ◽  
Control Measures ◽  
Limiting Factor ◽  
Embryonic Cells ◽  
Biomedical Sciences ◽  
Egg Morphology

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

scholarly journals Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae) population in California

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 194 ◽  
Author(s):  
Anthony J. Cornel ◽  
Jodi Holeman ◽  
Catelyn C. Nieman ◽  
Yoosook Lee ◽  
Charles Smith ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Mosquito Species ◽  
Residential Areas ◽  
Mosquito Abundance ◽  
New Locations ◽  
New Formulation ◽  
A Site ◽  
Bg Sentinel ◽  
And Control

The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.

scholarly journals Insecticide resistance selection and reversal in two strains of Aedes aegypti

2020 ◽  
Vol 5 ◽  
pp. 183
Author(s):  
Jonathan Thornton ◽  
Bruno Gomes ◽  
Constância Ayres ◽  
Lisa Reimer
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Competence ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Metabolic Resistance ◽  
Resistance Selection ◽  
Similar Phenotype ◽  
Target Site Resistance ◽  
Homozygous Resistant

Background: Laboratory reared mosquito colonies are essential tools to understand insecticide action. However, they differ considerably from wild populations and from each other depending on their origin and rearing conditions, which makes studying the effects of specific resistance mechanisms difficult. This paper describes our methods for establishing multiple resistant strains of Aedes aegypti from two colonies as a new resource for further research on metabolic and target site resistance. Methods: Two resistant colonies of Ae. aegypti, from Cayman and Recife, were selected through 10 generations of exposure to insecticides including permethrin, malathion and temephos, to yield eight strains with different profiles of resistance due to either target site or metabolic resistance. Resistance ratios for each insecticide were calculated for the selected and unselected strains. The frequency of kdr alleles in the Cayman strains was determined using TaqMan assays. A comparative gene expression analysis among Recife strains was conducted using qPCR in larvae (CCae3A, CYP6N12, CYP6F3, CYP9M9) and adults (CCae3A, CYP6N12, CYP6BB2, CYP9J28a). Results: In the selected strain of Cayman, mortality against permethrin reduced almost to 0% and kdr became fixated by 5 generations. A similar phenotype was seen in the unselected homozygous resistant colony, whilst mortality in the susceptible homozygous colony rose to 82.9%. The Recife strains showed different responses between exposure to adulticide and larvicide, with detoxification genes in the temephos selected strain staying similar to the baseline, but a reduction in detoxification genes displayed in the other strains. Conclusions: These selected strains, with a range of insecticide resistance phenotypes and genotypes, will support further research on the effects of target-site and/or metabolic resistance mechanisms on various life-history traits, behaviours and vector competence of this important arbovirus vector.

scholarly journals Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae) population in California

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 194 ◽  
Author(s):  
Anthony J. Cornel ◽  
Jodi Holeman ◽  
Catelyn C. Nieman ◽  
Yoosook Lee ◽  
Charles Smith ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Mosquito Species ◽  
Residential Areas ◽  
Mosquito Abundance ◽  
New Locations ◽  
New Formulation ◽  
A Site ◽  
Bg Sentinel ◽  
And Control

The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.

scholarly journals Insecticide resistance selection and reversal in two strains of Aedes aegypti

2020 ◽  
Vol 5 ◽  
pp. 183
Author(s):  
Jonathan Thornton ◽  
Bruno Gomes ◽  
Constância Ayres ◽  
Lisa Reimer
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Competence ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Metabolic Resistance ◽  
Resistance Selection ◽  
Similar Phenotype ◽  
Target Site Resistance ◽  
Homozygous Resistant

Background: Laboratory reared mosquito colonies are essential tools to understand insecticide action. However, they differ considerably from wild populations and from each other depending on their origin and rearing conditions, which makes studying the effects of specific resistance mechanisms difficult. This paper describes our methods for establishing multiple resistant strains of Aedes aegypti from two colonies as a new resource for further research on metabolic and target site resistance. Methods: Two resistant colonies of Ae. aegypti, from Cayman and Recife, were selected through 10 generations of exposure to insecticides including permethrin, malathion and temephos, to yield eight strains with different profiles of resistance due to either target site or metabolic resistance. Resistance ratios for each insecticide were calculated for the selected and unselected strains. The frequency of kdr alleles (F1534C and V1016I) in the Cayman strains was determined using TaqMan assays. A comparative gene expression analysis among Recife strains was conducted using qPCR in larvae (CCae3A, CYP6N12, CYP6F3, CYP9M9) and adults (CCae3A, CYP6N12, CYP6BB2, CYP9J28a). Results: In the selected strain of Cayman, mortality against permethrin reduced almost to 0% and kdr became fixated by 5 generations. A similar phenotype was seen in the unselected homozygous resistant colony, whilst mortality in the susceptible homozygous colony rose to 82.9%. The Recife strains showed different responses between exposure to adulticide and larvicide, with detoxification genes in the temephos selected strain staying similar to the baseline, but a reduction in detoxification genes displayed in the other strains. Conclusions: These selected strains, with a range of insecticide resistance phenotypes and genotypes, will support further research on the effects of target-site and/or metabolic resistance mechanisms on various life-history traits, behaviours and vector competence of this important arbovirus vector.

scholarly journals Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae) population in California

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 194 ◽  
Author(s):  
Anthony J. Cornel ◽  
Jodi Holeman ◽  
Catelyn C. Nieman ◽  
Yoosook Lee ◽  
Charles Smith ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Mosquito Species ◽  
Residential Areas ◽  
Mosquito Abundance ◽  
New Locations ◽  
New Formulation ◽  
A Site ◽  
Bg Sentinel ◽  
And Control

The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.

High-quality genome assembly of Huazhan and Tianfeng, the parents of an elite rice hybrid Tian-you-hua-zhan

2021 ◽  
Author(s):  
Hui Zhang ◽  
Yuexing Wang ◽  
Ce Deng ◽  
Sheng Zhao ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Genome Assembly ◽  
High Quality ◽  
Rice Hybrid ◽  
High Quality Genome

scholarly journals Etiological, epidemiological, and clinical features of acute diarrhea in China

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Li-Ping Wang ◽  
◽  
Shi-Xia Zhou ◽  
Xin Wang ◽  
Qing-Bin Lu ◽  
...  
Keyword(s):  
Clinical Features ◽  
Acute Diarrhea ◽  
Vibrio Parahaemolyticus ◽  
Bacterial Pathogens ◽  
Control Measures ◽  
Viral Pathogens ◽  
Rotavirus A ◽  
Positive Rate ◽  
Prevention And Control Measures ◽  
And Control

AbstractNational-based prospective surveillance of all-age patients with acute diarrhea was conducted in China between 2009‒2018. Here we report the etiological, epidemiological, and clinical features of the 152,792 eligible patients enrolled in this analysis. Rotavirus A and norovirus are the two leading viral pathogens detected in the patients, followed by adenovirus and astrovirus. Diarrheagenic Escherichia coli and nontyphoidal Salmonella are the two leading bacterial pathogens, followed by Shigella and Vibrio parahaemolyticus. Patients aged <5 years had higher overall positive rate of viral pathogens, while bacterial pathogens were more common in patients aged 18‒45 years. A joinpoint analysis revealed the age-specific positivity rate and how this varied for individual pathogens. Our findings fill crucial gaps of how the distributions of enteropathogens change across China in patients with diarrhea. This allows enhanced identification of the predominant diarrheal pathogen candidates for diagnosis in clinical practice and more targeted application of prevention and control measures.

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