Biology subjects

Surendran, S. N.

Publications and source records attributed to Surendran, S. N..

5 recordsLinked to original sources

bioRxiv2024

Sequencing 1206 genomes reveals origin and movement of Aedes aegypti driving increased dengue risk

The number of dengue cases worldwide has increased ten-fold over the past decade as Aedes aegypti, the primary vector of this disease, thrives and expands its distribution, revealing limitations to current control methods. To better understand how Ae. aegypti evolved from a forest dwelling, generalist species to a highly anthropophilic urban species and the impact of contemporary gene flow on the future of dengue control, we sequenced 1,206 genomes from mosquitoes collected at 74 locations around the globe. Here we show that after evolving a preference for humans in the Sahel region of West Africa, the origin of the fully domesticated, anthropophilic subspecies Ae. aegypti aegypti (Aaa) occurred in the Americas during the Atlantic Slave Trade era and was followed by its explosive expansion around the globe. In recent decades, Aaa has invaded coastal Africa, the ancestral home range, introducing insecticide resistance mutations and an affinity for human hosts. Evidence of back-to-Africa migration is found in regions with recent dengue outbreaks, raising concern that global movement of Aaa could increase transmission risk of arboviruses including dengue in urban Africa. These data provide a platform to further study this important mosquito vector species and underscore developing complexity in the fight to limit the spread of dengue, Zika, and chikungunya diseases.

genomics↗

bioRxiv2024

Preimaginal development of Aedes aegypti in brackish water produces adult mosquitoes with thicker cuticles and greater insecticide resistance

Aedes aegypti and Aedes albopictus mosquitoes, the principal vectors of many human arboviral diseases, lay eggs and undergo preimaginal development in fresh water habitats. They have also recently been found to develop in brackish water in coastal areas. Adult females emerging from brackish water-developing Ae. aegypti larvae are shown to possess thicker cuticles and greater resistance to common insecticides used against adults (adulticides) compared with fresh water Ae. aegypti. These findings are compatible with previous findings showing that brackish water Ae. aegypti larvae possess thicker cuticles and greater larvicide resistance. Greater resistance of salinity-tolerant Ae. aegypti to adulticides and larvicides is a hitherto unappreciated problem for controlling arboviral diseases and has implications also for other mosquito-borne diseases.

zoology↗

bioRxiv2024

Lectin Microarray Analysis of Salivary Gland Glycoproteins from the Arboviral Vector Aedes aegypti and the Malaria Vector Anopheles stephensi

Salivary gland glycoconjugates in human-feeding insects and arachnids can elicit hypersensitivity reactions. Glycoproteins introduced during blood feeding by arachnid ticks are responsible for red meat allergy or the -gal syndrome. Dengue virus transmitted by Aedes mosquitoes incorporates mosquito glycoproteins into its envelope and malaria parasites transmitted by Anopheles mosquitoes reportedly express -gal epitopes that are potentially derived from mosquito salivary glands. Tick salivary gland glycoproteins possess -gal epitopes. We used microarrays containing forty different lectins to analyse salivary gland protein glycoconjugates from the principal arboviral vector Aedes aegypti and the rapidly spreading malaria vector Anopheles stephensi. Salivary gland glycoproteins of both mosquitoes possessed very similar lectin-binding specificities. Lectin-binding profiles showed the significant presence of oligomannose N-glycans and O-glycans, a limited presence of glycan structures capped with terminal GalNAc, GlcNAc, {beta} linked Gal, 1-6 linked fucose, and no detectable sialic acids or terminal -linked Gal in salivary gland glycoproteins.

zoology↗

bioRxiv2023

Aalbo1200: global genetic differentiation and variability of the mosquito Aedes albopictus

The mosquito Aedes albopictus transmits human viruses including dengue and chikungunya and is an extremely successful invasive species expanding into new regions of the world. New tools are needed to complement existing tools to help monitor and control this species. Genomic resources are improving for this species including genome reference sequences, and whole genome sequencing data will help to catalog genetic diversity in this species and further enable genetic analysis. We collected populations of Ae. albopictus from throughout its distribution and generated whole genome sequencing data from population samples. These data will be used to address a number of basic and applied questions for this species. Here, we show genetic differentiation patterns among the tropical and temperate forms, as well as finer scale genetic clustering at the regional and population scale. These data and results will be a valuable resource for further study and tool development for this species.

evolutionary biology↗

bioRxiv2020

Molecular forms of Anopheles subpictus s.l. and Anopheles sundaicus s.l. in the Indian subcontinent

BackgroundAnopheles subpictus s.l. and Anopheles sundaicus s.l. are closely related species, each comprising of several sibling species. Ambiguities exist in the classification of these two nominal species and the specific status of members of An. subpictus complex. Identifying fixed molecular forms and mapping their spatial distribution will help in resolving the taxonomic ambiguities and understanding their relative epidemiological significance. MethodsDNA sequencing of Internal Transcribed Spacer-2 (ITS2), 28S-rDNA (D1-to-D3 domains) and cytochrome oxidase-II of morphologically identified specimens of two nominal species, An. subpictus s.l. and An. sundaicus s.l. collected from the Indian subcontinent, was performed and subjected to genetic distance and molecular phylogenetic analyses. ResultsMolecular characterization of mosquitoes for rDNA revealed the presence of two molecular forms of An. sundaicus s.l. (identified as An. epiroticus s.s. and An. sundaicus D) and three molecular forms of An. subpictus s.l. (provisionally designated as Form A, B and C) in the Indian subcontinent. Phylogenetic analyses revealed two distinct clades: (i) subpictus clade, with a single molecular form of An. subpictus (Form A) prevalent in mainland India and Sri Lanka, and (ii) sundaicus clade, comprising of members of Sundaicus Complex., two molecular forms of An. subpictus s.l., (Form B and C) prevalent in coastal areas or islands, and molecular forms reported from Thailand and Indonesia. Based on the number of float-ridges on eggs, all An. subpictus molecular Form B were classified as Species B whereas majority (80%) of the molecular Form A were classified as sibling species C. Fixed intragenomic sequence variation in ITS2 with the presence of two haplotypes was found in molecular Form A throughout its distribution. ConclusionA total of three molecular forms of An. subpictus s.l. and two molecular forms of An. sundaicus s.l. were recorded in the Indian subcontinent. Phylogenetically, two forms of An. subpictus s.l., (Form B and C) prevalent in coastal areas or islands in the Indian subcontinent and molecular forms reported from Southeast Asia are members of Sundaicus Complex. Molecular Form A of An. subpictus is distantly related to all other forms and deserve a distinct specific status. Presence of An. epiroticus in Indian territory is recorded for the first time.

zoology↗