Niranjana Krishnan (she/her) obtained her PhD in Toxicology from the Entomology department at Iowa State University. Working with Profs. Steven Bradbury and Joel Coats, she assessed the risk of insecticide exposures on monarch butterflies. Niranjana obtained a Bachelor's degree in Microbiology from University of Mumbai and a Master's degree in Biomedical Genetics from Vellore Institute of Technology, India.
Niranjana's current research interest is to apply in vivo, in vitro, and in silico techniques to estimate risk of chemical exposures on insect species, including species of conservation concern. This is being undertaken via three research themes that employ the adverse outcome pathway (AOP) framework: Research Theme 1: AOP development from molecular initiating events to organismal effects Research Theme 2: AOP development from organismal to population level effects Research Theme 3: AOP employment to inform interspecies extrapolation
Elucidating arrested pupal ecdysis Neonicotinoids, nicotinic acetylcholine receptor (nAChR) agonists, disrupt larval to pupal ecdysis in Lepidoptera. The doses that cause this effect are 10 to 100-fold lower than doses that cause outright mortality. We are elucidating the mechanism through which neonicotinoids, and potentially other chemicals that overstimulate nAChRs, cause arrest in pupation. We are also studying if other insect orders show a similar effect and investigating the interplay between neuroendocrine hormones and neurotransmitters. This project has implications for non-target risk assessment and pesticide development.
Assessing interspecies differences in insecticide susceptibility Insects can show large variations in insecticide susceptibility within and across orders. We are undertaking studies to identify species that show high and low susceptibility to major insecticide classes and assessing toxicokinetic and toxicodynamic factors that can help explain differences in susceptibility. The ultimate goal is to identify surrogate target and non-target species for testing and develop a framework that can be used to predict species' responses to untested chemicals.
Ecotoxicology & Risk Assessment Lab
Conservation of at-risk invertebrate species, Advancing Tox21 in invertebrate toxicology
Missouri University of Science and Technology Start-Up Funding
Elucidation of arrested pupal ecdysis: a novel, newly discovered insecticidal mode of action to manage a diversity of insect pests U.S. Department of Agriculture (January 2022 to December 2023)
Elucidating differences in pesticide susceptibility across two butterfly species Missouri S&T First Year Research Experience Program (January to May 2022)
Understanding the effect neonicotinoid insecticides have on insect pupal development Iowa State University Henry and Sylvia Richardson Research Incentive Grant (2020)
Assessing the risk of insecticides to monarch butterflies Xerces Society The Joan Mosenthal DeWind Award (2019-2020)
Evaluation of a Varroa Mite (Varroa destructor)-Active dsRNA via Dietary Exposure to Monarch Butterfly (Danaus plexippus) Larvae Bayer Crop Science (2018-2020)
Milkweed in Prairie Plots in Agricultural Landscapes: Assessing Risks of Insecticide Exposure to Monarch Butterfly Larvae Prairie Biotic Research Small Grants (2018-2019).