Biology subjects

Johnson, E. J.

Publications and source records attributed to Johnson, E. J..

3 recordsLinked to original sources

bioRxiv2023

Human Ageing Genomic Resources: updates on key databases in ageing research

Ageing is a complex and multifactorial process. For two decades, the Human Ageing Genomic Resources (HAGR) have aided researchers in the study of various aspects of ageing and its manipulation. Here we present the key features and recent enhancements of these resources, focusing on its six main databases. One database, GenAge, focuses on genes related to ageing, featuring 307 genes linked to human ageing and 2205 genes associated with longevity and ageing in model organisms. AnAge focuses on ageing, longevity, and life-history across animal species, containing data on 4645 species. DrugAge includes information about 1097 longevity drugs and compounds in model organisms such as mice, rats, flies, worms, and yeast. GenDR provides a list of 214 genes associated with the life-extending benefits of dietary restriction in model organisms. CellAge contains a catalogue of 866 genes associated with cellular senescence. The LongevityMap serves as a repository for genetic variants associated with human longevity, encompassing 3144 variants pertaining to 884 genes. Additionally, HAGR provides various tools as well as gene expression signatures of ageing, dietary restriction, and replicative senescence based on meta-analyses. Our databases are integrated, regularly updated, and manually curated by experts. HAGR is freely available online (https://genomics.senescence.info/).

bioinformatics↗

bioRxiv2022

Vaporous essential oils and isolates restore pyrethroid-treated netting efficacy to Aedes aegypti (Diptera: Culicidae)

Decreasing opportunities for mosquitoes to bite is critical in the reduction of mosquito-borne pathogen transmission, such as Plasmodium spp. or dengue, yellow fever, and West Nile viruses. Field-evolved resistance to a large selection of synthetic insecticides is crippling efforts to reduce mosquito populations and new strategies are necessary to sustain the efficacy of commercially available tools. Aedes aegypti (L.), among other species, have evolved pyrethroid resistance in the field and the pyrethroid-resistant Puerto Rico (PR) strain is a valuable tool for understanding resistance mechanisms. A previous study showed that pyrethroid efficacy can be enhanced by pre-exposing the PR strain to essential oil vapors before topical application of deltamethrin. Insecticide-treated nets (ITNs) and long-lasting insecticidal nets (LLINs) are current products commercialized for mosquito bite protection, but nets using pyrethroids are losing efficacy in the field due to field-evolved pyrethroid resistance. This study tested essential oils previously identified to affect pyrethroid efficacy, as well as their main isolates, to assess if they can restore the efficacy of pyrethroid-treated LLIN against the PR strain. We show that although amyris (Amyris balsamifera) expectedly decreases net efficacy, increased mortality can be obtained after exposure to tagetes (Tagetes bipinnata) and cajeput (Melaleuca cajuputi) oils, but also after exposure to their isolates, such as dihydro tagetone and ocimene, from 1 h after exposure to the net. This study provides a selection of promising synergists used as vaporous emanations to restore pyrethroid efficacy and counteract field-evolved resistance in mosquitoes.

pharmacology and toxicology↗

bioRxiv2017

Forgot what you like? Evidence for hippocampal dependence of value-based decisions

Consistent decisions are intuitively desirable and theoretically important for utility maximization. Neuroeconomics has established the neurobiological substrate of value representation, but brain regions that provide input to the value-processing network is less explored. The constructed-preference tradition within behavioral decision research gives a critical role to cognitive processes that rely on associations, suggesting a role for the hippocampus in making decisions and to do so consistently. We compared the performance of 31 patients with mediotemporal lobe (MTL) epilepsy and hippocampal lesions, 30 patients with extratemporal lobe epilepsy, and 30 healthy controls on two tasks: binary choices between candy bars based on their preferences and a number-comparison control task where the larger number is chosen. MTL patients make more inconsistent choices than the other two groups for the value-based choice but not the number-comparison task. These inconsistencies increase with the volume of compromised hippocampal tissue. These results suggest a critical involvement of the MTL in preference construction and value-based choices.\n\nSignificanceOur days are full of choices that reflect our preferences. Economics lays out models of how to optimally make these decisions. Neuroeconomics has identified a cortical value-processing network whose activity correlates with constructs related to valuation and choice in economic models. However open questions remain: How are these value signals formed, and what regions might be necessary for retrieving and computing these value signals? Inspired by cognitive models calling on associative processes in value-based decisions, this paper uses unique neuropsychological data to establish the critical role of the medial temporal lobe in making consistent choices and further informs our understanding of the value-processing network.

animal behavior and cognition↗