Roopa Samal | University of Delhi (original) (raw)

Papers by Roopa Samal

Journal of applied and natural science, Jun 19, 2024

Phytoparasitica, Mar 13, 2024

Journal of Tropical Medicine, Jan 5, 2024

Journal of Applied and Natural Science

Aedes-borne diseases are of worldwide concern due to the lack of effective medicine and vaccinati... more Aedes-borne diseases are of worldwide concern due to the lack of effective medicine and vaccination. Frequent use of chemical intervention has developed insecticide resistance in mosquitoes and posed health risks to humans and the environment, necessitating an effective and safer intervention. Graphene Oxide (GO) is an efficient material that can absorb pesticide particles and release pesticide macromolecules in a controlled manner. With the proposition that magnetic graphene oxide (MGO)-based nanoformulations can be an eco-safe and effective material for pesticide conjugation, the present study synthesized these nanoformulations conjugated with a pyrethroid, deltamethrin (DL) through chemical co-precipitation method. The formulations were validated using biophysical techniques and investigated for their efficacy against Aedes aegypti. The X-ray diffraction (XRD) pattern of nanocomposites showed six intense diffraction peaks of Fe3O4 particles, X-ray photoelectron spectroscopy (XPS)...

Gazi Entomolojik Arastirmalar Dernegi, Mar 29, 2023

Malaria Journal

Background Attractive toxic sugar bait (ATSB) is a promising “attract and kill”-based approach fo... more Background Attractive toxic sugar bait (ATSB) is a promising “attract and kill”-based approach for mosquito control. It is a combination of flower nectar/fruit juice to attract the mosquitoes, sugar solution to stimulate feeding, and a toxin to kill them. Selecting an effective attractant and optimizing concentration of toxicant is significant in the formulation of ATSB. Methods Current study formulated an ATSB using fruit juice, sugar and deltamethrin, a synthetic pyrethroid. It was evaluated against two laboratory strains of Anopheles stephensi. Initial studies evaluated comparative attractiveness of nine different fruit juices to An. stephensi adults. Nine ASBs were prepared by adding fermented juices of plum, guava, sweet lemon, orange, mango, pineapple, muskmelon, papaya, and watermelon with 10% sucrose solution (w/v) in 1:1 ratio. Cage bioassays were conducted to assess relative attraction potential of ASBs based on the number of mosquito landings on each and the most effectiv...

Biology bulletin of the Russian Academy of Sciences, Dec 1, 2021

GEDRAG & ORGANISATIE REVIEW, 2021

Frontiers in Physiology

Despite the continuous use of chemical interventions, Aedes-borne diseases remain on the rise. Ne... more Despite the continuous use of chemical interventions, Aedes-borne diseases remain on the rise. Neonicotinoids are new, safer, and relatively effective pharmacological interventions against mosquitoes. Neonicotinoids interact with the postsynaptic nicotinic acetylcholine receptors (nAChRs) of the insect central nervous system, but the absence of nAChR polymorphism in resistant phenotypes makes their involvement in neonicotinoid resistance uncertain. Thus, an investigation was carried out to understand the role of metabolic detoxification and target site insensitivity in imparting acetamiprid resistance in Aedes aegypti larvae. Studies were conducted on the parent susceptible strain (PS), acetamiprid-larval selected strain for five generations (ACSF-5; 8.83-fold resistance) and 10 generations (ACSF-10; 19.74-fold resistance) of Ae. aegypti. The larval selection raised α-esterase and β-esterase activities by 1.32-fold and 1.34-fold, respectively, in ACSF-10 as compared to PS, while the...

Journal of Tropical Medicine

Background. Attractive toxic sugar bait (ATSB), based on “attract and kill” approach, is a novel ... more Background. Attractive toxic sugar bait (ATSB), based on “attract and kill” approach, is a novel and promising strategy for mosquito control. Formulation of an attractive sugar bait (ASB) solution by selecting an efficient olfaction stimulant and preparation of an optimized sugar-attractant dosage is a significant component for the success of the approach. Methods. Current study evaluated relative potential of nine ASBs, formulated by combination of sugar and fresh fruit juices (guava, mango, muskmelon, orange, papaya, pineapple, plum, sweet lemon, and watermelon) in attracting Aedes aegypti adults. Freshly extracted and 48-hour-fermented juices were combined with 10% sucrose solution (w/v) in 1 : 1 ratio. Cage bioassays were conducted against two laboratory strains (susceptible: AND-Aedes aegypti; deltamethrin-selected: AND-Aedes aegypti-DL10) and two field-collected strains (Shahdara strain of Aedes aegypti: SHD-Delhi; Govindpuri strain of Aedes aegypti: GVD-Delhi). Each of the ni...

Journal of Applied and Natural Science, 2021

Aedes aegypti management is a global concern due to the absence of medication and effective vacci... more Aedes aegypti management is a global concern due to the absence of medication and effective vaccines. The pesticide-mediated health hazards and rising insecticide resistance in mosquitoes have aggravated the issues. As graphene Oxide (GO)- based nanoformulations are considered a novel mosquito management strategy; the present investigation evaluated the efficacy of GO-based nanoformulations conjugated with malathion (ML) and endosulphan (EN) against Ae. aegypti. The GO was synthesised by Hummers’ method and was confirmed by UV-visible spectral analysis. The GO-ML and GO-EN binary mixtures (1:1 and 1:2) were assayed for toxic potential against mosquito larvae as per WHO protocol and the dead larvae were scrutinized for morphological deformations/abnormalities. The contact irritancy potential of GO nanoformulations was also evaluated against adult Ae. aegypti. The UV-visible spectrum of GO showed a narrow and high peak at ~300 nm corresponding to an n-π* plasmon peak. The GO-insectici...

International Journal of Tropical Insect Science, 2021

Aedes aegypti is of utmost public health concern transmitting various diseases of human health co... more Aedes aegypti is of utmost public health concern transmitting various diseases of human health concern. Employment of chemical-based control interventions has induced immunity in mosquitoes, harmed environment, and adversely affected human health and non-targets diverting the research focus on alternate measures. Current study investigates the efficacy of an Insect Growth Regulator, lufenuron, against early fourth instars of Ae. aegypti. The larvae exposed to lufenuron for 24 h were assessed for the effects on the development and adult emergence. The impact of sub-lethal and median-lethal dose of lufenuron was determined on the nutrients and detoxification enzymes of Ae. aegypti. The larvae exposed to lufenuron showed reduced adult emergence exhibiting the respective IE30 and IE50 as 0.13 μg/L and 0.96 μg/L. Larval treatment with IE30 and IE50 lufenuron reduced the carbohydrate and lipid content in Ae. aegypti. However, the protein levels in the larvae decreased only on exposure to IE30 lufenuron while increased with IE50 lufenuron. Besides, IE30 and IE50 lufenuron treatment elevated α-esterases (1.05-fold; 1.15-fold); β-esterases (1.29-fold;1.62-fold), and Glutathione-S-transferases (1.19-fold; 3.1-fold) expression in the Ae. aegypti larvae. The % acetylcholinesterase inhibition also reduced by 3.75-fold and 2.07-fold, correspondingly, while the cytochrome P450 monooxygenase expression rose (1.15-fold) only with IE50 dosage of lufenuron. It is suggested that lufenuron stress probably ampliflied the catabolism of nutrients and expression of metabolic detoxifying enzymes in Ae. aegypti larvae in order to meet higher energy requirements and counteract the adverse effects of lufenuron. This is the first ever report unravelling the effect of lufenuron on the biochemical parameters of Ae. aegypti larvae.

Proceedings of the International Conference and the 10th Congress of the Entomological Society of Indonesia (ICCESI 2019), 2020

Red Cotton Bug, Dysdercus koenigii (Fabr.) (Hemiptera:Pyrrhocoridae), commonly called cotton stai... more Red Cotton Bug, Dysdercus koenigii (Fabr.) (Hemiptera:Pyrrhocoridae), commonly called cotton stainer, is a damaging pest of cotton and other economical crops in Asia. Nymphs as well as adult of this pest suck the sap from the green bolls and leaves of cotton causing shedding of young bolls, rotting of green bolls, stained cotton fibers and loss of seed viability. The present study evaluates the toxic and growth regulatory effects of a pyrethroid, beta-cyfluthrin against D. koenigii. The newly emerged fifth instars nymphs were exposed to beta-cyfluthrin at concentration ranging from 0.00008% to 0.00128%. A volume of 1μL of beta-cyfluthrin was topically applied on the dorsal anterior thoracic region of nymphs (in 3 replicates, each replicate containing batch of 25 insects) and were observed for mortality after 24 hr. The nymphs were further reared till adults to observe delayed toxicity effects and developmental abnormalities, if any. The result revealed significant lethal effects of ...

Chemical control of dengue vector, Aedes aegypti is impaired due to development of resistance to ... more Chemical control of dengue vector, Aedes aegypti is impaired due to development of resistance to conventional insecticides. Insect Growth Regulators (IGRs) are considered more suitable and effective vector control agents as they specifically inhibit chitin biosynthesis, a process absent in vertebrates, and impose less adverse effects on beneficial insects and the environment. Present study investigates Lufenuron, a Chitin Synthesis Inhibitor (CSI), as a control agent of Ae. aegypti. Different instars of Ae. aegypti were exposed to a range of concentrations of Lufenuron as per WHO protocol. The investigations showed the effective hormone-mimetic effect of Lufenuron resulting in the formation of a significant number of larval-pupal and pupal-adult intermediates with the maximum number observed on exposure to L3 (L-P=17%, P-A=21%). Approximately 20% of L2 instars either could not moult and remained trapped inside the new exuviae or possessed bulged abdomen while some showed ruptured ex...

Acta Ecologica Sinica, 2018

Upgrade your existing EDX system with the world leader in affordable EDX upgrades. Our new digita... more Upgrade your existing EDX system with the world leader in affordable EDX upgrades. Our new digital pulse processor provides increased throughput and will interface to most EDS detectors. Precise Standardless quantitation for even complex matricies "Active" digital imaging, linescans, and x-ray mapping. Combining digital imaging with our EDS system produces a very simple yet powerful Microanalysis system.

The Open Parasitology Journal, 2018

Background: Mosquito control is a major concern throughout the world because of rising cases of m... more Background: Mosquito control is a major concern throughout the world because of rising cases of mosquito-borne diseases. The outbreak of Zika, Dengue and Chikungunya has caused grave situations raising urgent need to control Aedes aegypti. Moreover, extensive use of synthetic insecticides in mosquito control programs has resulted in high levels of insecticide resistance leading to the use of magnified concentrations, impacting human health and environment adversely. The knowledge about current status of the insecticide susceptibility against Ae. aegypti could help to devise mosquito control strategy. Objective: Present study evaluates the larvicidal potential of thirteen insecticides belonging to seven different classes; organochlorines, organophosphates, carbamates, pyrethroids, neonicotinoids, avermectins and secondary metabolites; against early fourth instars of Ae. aegypti. Materials and Methods: The insecticide susceptibility was evaluated as per WHO protocol. Fatality counts w...

Vector Biology Journal, 2017