scholarly journals Automated phenotyping of mosquito larvae enables high-throughput screening for novel larvicides and smartphone-based detection of larval insecticide resistance

2020 ◽  
Author(s):  
Steven D. Buckingham ◽  
Frederick A. Partridge ◽  
Beth C. Poulton ◽  
Ben Miller ◽  
Rachel A. McKendry ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
High Throughput ◽  
High Throughput Screening ◽  
Pyrethroid Resistance ◽  
Standard Test ◽  
Mosquito Larvae ◽  
Mosquito Vector ◽  
Chemical Screening ◽  
Field Assay ◽  
Automated Phenotyping

AbstractPyrethroid-impregnated nets have contributed significantly to halving the burden of malaria but resistance threatens their future efficacy and the pipeline of new insecticides is short. Here we report that an invertebrate automated phenotyping platform (INVAPP), combined with the algorithm Paragon, provides a robust system for measuring larval motility in Anopheles gambiae (and An. coluzzi) as well as Aedes aegypti with the capacity for high-throughput screening for new larvicides. By this means, we reliably quantified both time- and concentration-dependent actions of chemical insecticides faster than using the WHO standard larval assay. We illustrate the effectiveness of the system using an established larvicide (temephos) and demonstrate its capacity for library-scale chemical screening using the Medicines for Malaria (MFP) Pathogen-Box library. As a proof-of-principle, this library screen identified a compound, subsequently confirmed to be tolfenpyrad, as an effective larvicide. We have also used the INVAPP / Paragon system to enable detection of resistance to deltamethrin. We show how this approach to monitoring larval susceptibility to insecticides can be adapted for use with a smartphone camera application and therefore has potential for further development as a simple portable field-assay for insecticide resistance with associated real-time, geo-located information to identify hotspots.Author summaryWe have developed an automated platform for recording the motility of mosquito larvae and applied it to larvae of a mosquito vector of malaria and a mosquito vector of dengue, Zika, yellow fever and other human diseases. The platform facilitates high-throughput, chemical screening for new compounds to control mosquito larvae and also allows detection of larval resistance to the pyrethroid insecticide deltamethrin. Pyrethroid-impregnated bednets have helped to halve the deaths from malaria in recent years but pyrethroid resistance is an important threat to this progress. Our approach assays insecticide actions faster than the current WHO standard test and we show that it can be adapted for use with a smartphone, which offers the prospect of a future field assay for resistance with the added benefit of precise satellite-based location.

scholarly journals Automated phenotyping of mosquito larvae enables high-throughput screening for novel larvicides and offers potential for smartphone-based detection of larval insecticide resistance

2021 ◽  
Vol 15 (6) ◽  
pp. e0008639
Author(s):  
Steven D. Buckingham ◽  
Frederick A. Partridge ◽  
Beth C. Poulton ◽  
Benjamin S. Miller ◽  
Rachel A. McKendry ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Mosquito Larvae ◽  
Chemical Screening ◽  
Field Assay ◽  
Library Screen ◽  
Automated Phenotyping ◽  
Robust System ◽  
Further Development ◽  
Proof Of Principle

Pyrethroid-impregnated nets have contributed significantly to halving the burden of malaria but resistance threatens their future efficacy and the pipeline of new insecticides is short. Here we report that an invertebrate automated phenotyping platform (INVAPP), combined with the algorithm Paragon, provides a robust system for measuring larval motility in Anopheles gambiae (and An. coluzzi) as well as Aedes aegypti with the capacity for high-throughput screening for new larvicides. By this means, we reliably quantified both time- and concentration-dependent actions of chemical insecticides faster than using the WHO standard larval assay. We illustrate the effectiveness of the system using an established larvicide (temephos) and demonstrate its capacity for library-scale chemical screening using the Medicines for Malaria Venture (MMV) Pathogen Box library. As a proof-of-principle, this library screen identified a compound, subsequently confirmed to be tolfenpyrad, as an effective larvicide. We have also used the INVAPP / Paragon system to compare responses in larvae derived from WHO classified deltamethrin resistant and sensitive mosquitoes. We show how this approach to monitoring larval response to insecticides can be adapted for use with a smartphone camera application and therefore has potential for further development as a simple portable field-assay with associated real-time, geo-located information to identify hotspots.

scholarly journals Antagonism screen for inhibitors of bacterial cell wall biogenesis uncovers an inhibitor of undecaprenyl diphosphate synthase

2015 ◽  
Vol 112 (35) ◽  
pp. 11048-11053 ◽  
Author(s):  
Maya A. Farha ◽  
Tomasz L. Czarny ◽  
Cullen L. Myers ◽  
Liam J. Worrall ◽  
Shawn French ◽  
...  
Keyword(s):  
Cell Wall ◽  
High Throughput ◽  
High Throughput Screening ◽  
Teichoic Acid ◽  
Antibacterial Drug ◽  
Wall Teichoic Acid ◽  
Chemical Screening ◽  
Cellular Processes ◽  
Cell Wall Biogenesis ◽  
Antagonistic Interactions

Drug combinations are valuable tools for studying biological systems. Although much attention has been given to synergistic interactions in revealing connections between cellular processes, antagonistic interactions can also have tremendous value in elucidating genetic networks and mechanisms of drug action. Here, we exploit the power of antagonism in a high-throughput screen for molecules that suppress the activity of targocil, an inhibitor of the wall teichoic acid (WTA) flippase in Staphylococcus aureus. Well-characterized antagonism within the WTA biosynthetic pathway indicated that early steps would be sensitive to this screen; however, broader interactions with cell wall biogenesis components suggested that it might capture additional targets. A chemical screening effort using this approach identified clomiphene, a widely used fertility drug, as one such compound. Mechanistic characterization revealed the target was the undecaprenyl diphosphate synthase, an enzyme that catalyzes the synthesis of a polyisoprenoid essential for both peptidoglycan and WTA synthesis. The work sheds light on mechanisms contributing to the observed suppressive interactions of clomiphene and in turn reveals aspects of the biology that underlie cell wall synthesis in S. aureus. Further, this effort highlights the utility of antagonistic interactions both in high-throughput screening and in compound mode of action studies. Importantly, clomiphene represents a lead for antibacterial drug discovery.

scholarly journals An automated high-throughput system for phenotypic screening of chemical libraries onC. elegansand parasitic nematodes

2017 ◽  
Author(s):  
Frederick A. Partridge ◽  
Anwen E. Brown ◽  
Steven D. Buckingham ◽  
Nicky J. Willis ◽  
Graham M. Wynne ◽  
...  
Keyword(s):  
High Throughput ◽  
Crop Damage ◽  
Parasitic Nematodes ◽  
Chemical Library ◽  
Trichuris Muris ◽  
Chemical Screening ◽  
Automated Phenotyping ◽  
Global Threat ◽  
Therapeutic Compounds ◽  
Parasitic Worms

AbstractParasitic nematodes infect hundreds of millions of people and farmed livestock. Further, plant parasitic nematodes result in major crop damage. The pipeline of therapeutic compounds is limited and parasite resistance to the existing anthelmintic compounds is a global threat. We have developed an INVertebrate Automated Phenotyping Platform (INVAPP) for high-throughput, plate-based chemical screening, and an algorithm (Paragon) which allows screening for compounds that have an effect on motility and development of parasitic worms. We have validated its utility by determining the efficacy of a panel of known anthelmintics against model and parasitic nematodes:Caenorhabditis elegans, Haemonchus contortus, Teladorsagia circumcincta, andTrichuris muris. We then applied the system to screen the Pathogen Box chemical library in a blinded fashion and identified known anthelmintics, including tolfenpyrad, auranofin, and mebendazole and 14 compounds previously undescribed as anthelmintics, including benzoxaborole and isoxazole chemotypes. This system offers an effective, high-throughput system for the discovery of novel anthelmintics.

scholarly journals Nonlinear Dose–Response Modeling of High-Throughput Screening Data Using an Evolutionary Algorithm

Dose-Response ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 155932582092673
Author(s):  
Jun Ma ◽  
Eric Bair ◽  
Alison Motsinger-Reif
Keyword(s):  
High Throughput ◽  
Dose Response ◽  
High Throughput Screening ◽  
Model Fitting ◽  
Logistic Models ◽  
Toxicity Testing ◽  
Nonlinear Least Squares ◽  
New Method ◽  
Chemical Screening ◽  
Response Modeling

Nonlinear dose–response relationships exist extensively in the cellular, biochemical, and physiologic processes that are affected by varying levels of biological, chemical, or radiation stress. Modeling such responses is a crucial component of toxicity testing and chemical screening. Traditional model fitting methods such as nonlinear least squares (NLS) are very sensitive to initial parameter values and often had convergence failure. The use of evolutionary algorithms (EAs) has been proposed to address many of the limitations of traditional approaches, but previous methods have been limited in the types of models they can fit. Therefore, we propose the use of an EA for dose–response modeling for a range of potential response model functional forms. This new method can not only fit the most commonly used nonlinear dose–response models (eg, exponential models and 3-, 4-, and 5-parameter logistic models) but also select the best model if no model assumption is made, which is especially useful in the case of high-throughput curve fitting. Compared with NLS, the new method provides stable and robust solutions without sensitivity to initial values.

scholarly journals A cytochrome P450 allele confers pyrethroid resistance on a major African malaria vector, reducing insecticide-treated bednet efficacy

2019 ◽  
Vol 11 (484) ◽  
pp. eaat7386 ◽  
Author(s):  
Gareth D. Weedall ◽  
Leon M. J. Mugenzi ◽  
Benjamin D. Menze ◽  
Magellan Tchouakui ◽  
Sulaiman S. Ibrahim ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Insecticide Resistance ◽  
Malaria Vector ◽  
Southern Africa ◽  
Malaria Control ◽  
Pyrethroid Resistance ◽  
Mosquito Vector ◽  
Metabolic Resistance ◽  
Pyrethroid Insecticides ◽  
The Impact

Metabolic resistance to insecticides such as pyrethroids in mosquito vectors threatens control of malaria in Africa. Unless it is managed, recent gains in reducing malaria transmission could be lost. To improve monitoring and assess the impact of insecticide resistance on malaria control interventions, we elucidated the molecular basis of pyrethroid resistance in the major African malaria vector, Anopheles funestus. We showed that a single cytochrome P450 allele (CYP6P9a_R) in A. funestus reduced the efficacy of insecticide-treated bednets for preventing transmission of malaria in southern Africa. Expression of key insecticide resistance genes was detected in populations of this mosquito vector throughout Africa but varied according to the region. Signatures of selection and adaptive evolutionary traits including structural polymorphisms and cis-regulatory transcription factor binding sites were detected with evidence of selection due to the scale-up of insecticide-treated bednet use. A cis-regulatory polymorphism driving the overexpression of the major resistance gene CYP6P9a allowed us to design a DNA-based assay for cytochrome P450–mediated resistance to pyrethroid insecticides. Using this assay, we tracked the spread of pyrethroid resistance and found that it was almost fixed in mosquitoes from southern Africa but was absent from mosquitoes collected elsewhere in Africa. Furthermore, a field study in experimental huts in Cameroon demonstrated that mosquitoes carrying the resistance CYP6P9a_R allele survived and succeeded in blood feeding more often than did mosquitoes that lacked this allele. Our findings highlight the need to introduce a new generation of insecticide-treated bednets for malaria control that do not rely on pyrethroid insecticides.

scholarly journals Automated phenotyping of Caenorhabditis elegans embryos with a high-throughput-screening microfluidic platform

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Huseyin Baris Atakan ◽  
Tunc Alkanat ◽  
Matteo Cornaglia ◽  
Raphaël Trouillon ◽  
Martin A. M. Gijs
Keyword(s):  
Caenorhabditis Elegans ◽  
High Throughput ◽  
High Throughput Screening ◽  
Microfluidic Platform ◽  
Automated Phenotyping

scholarly journals High-Throughput Chemical Screening for Antivirulence Developmental Phenotypes in Trypanosoma brucei

2014 ◽  
Vol 13 (3) ◽  
pp. 412-426 ◽  
Author(s):  
Paula MacGregor ◽  
Alasdair Ivens ◽  
Steven Shave ◽  
Iain Collie ◽  
David Gray ◽  
...  
Keyword(s):  
Small Molecules ◽  
Trypanosoma Brucei ◽  
High Throughput ◽  
High Throughput Screening ◽  
Morphological Changes ◽  
Specific Gene ◽  
African Trypanosomes ◽  
Chemical Screening

ABSTRACT In the bloodstream of mammalian hosts, the sleeping sickness parasite, Trypanosoma brucei , exists as a proliferative slender form or a nonproliferative, transmissible, stumpy form. The transition between these developmental forms is controlled by a density-dependent mechanism that is important for the parasite's infection dynamics, immune evasion via ordered antigenic variation, and disease transmissibility. However, stumpy formation has been lost in most laboratory-adapted trypanosome lines, generating monomorphic parasites that proliferate uncontrolled as slender forms in vitro and in vivo . Nonetheless, these forms are readily amenable to cell culture and high-throughput screening for trypanocidal lead compounds. Here, we have developed and exploited a high-throughput screen for developmental phenotypes using a transgenic monomorphic cell line expressing a reporter under the regulation of gene control signals from the stumpy-specific molecule PAD1. Using a whole-cell fluorescence-based assay to screen over 6,000 small molecules from a kinase-focused compound library, small molecules able to activate stumpy-specific gene expression and proliferation arrest were assayed in a rapid assay format. Independent follow-up validation identified one hit able to induce modest, yet specific, changes in mRNA expression indicative of a partial differentiation to stumpy forms in monomorphs. Further, in pleomorphs this compound induced a stumpy-like phenotype, entailing growth arrest, morphological changes, PAD1 expression, and enhanced differentiation to procyclic forms. This not only provides a potential tool compound for the further understanding of stumpy formation but also demonstrates the use of high-throughput screening in the identification of compounds able to induce specific phenotypes, such as differentiation, in African trypanosomes.

High-throughput screening program for botanical extracts

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
L Hingorani ◽  
NP Seeram ◽  
B Ebersole
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Screening Program ◽  
Botanical Extracts

High throughput screening of microbial biodiversity for the discovery of novel cosmeceutical agents

Planta Medica ◽  
2015 ◽  
Vol 81 (16) ◽  
Author(s):  
K Georgousaki ◽  
N DePedro ◽  
AM Chinchilla ◽  
N Aliagiannis ◽  
F Vicente ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Microbial Biodiversity
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