Dr. Vidya Devi Negi
Assistant Professor, Biological Sciences

The research interest of 2i-Lab

Bacterial evolution and the associated consequences

The lab is interested in exploring the Salmonella infection mediated pathogenies and associated immunological outcomes. Salmonella enterica serovar Typhimurium is a Gram-negative bacterium that infects many hosts, including amoeba, invertebrates, humans, and plants. S. Typhi is a human-specific serovar causing typhoid fever. 

In the 2i-lab, we examine how Salmonella infection can benefit the bug by adapting to the host environment. These evolutionary adaptations can help bacteria, and what mechanism makes the evolved bacteria more pathogenic than their non-adaptive counterparts. I am interested in further extrapolating the study to target using various other pathogens, including Listeria monocytogens, and Pseudomonas aeruginosa, responsible for causing significant mortality and morbidity. 

Bacterial evolution and the associated consequences

Also, I am interested in looking for the impact of Salmonella infection on obesity/diabetes and how bacterial infection can increase obesity and diabetes incidences using the worm Caenorhabditis elegans (C. elegans) model. Obesity and diabetes further increase the risk of various infections like Streptococcus infection etc., among the patient. Few reports describe the contrasting scenarios where microbe can lead to host obesity, especially viruses and the altered gut microbiota giving rise to the new field of infectobesity. The C. elegans is a well-established model system used for host-pathogen interaction, including Salmonella, Pseudomonas, immune response and immune signalling, obesity and diabetes. This global obesity and diabetes scenario led me to think about Salmonella infection mediated obesity and its association with diabetes using C. elegans as a model.

Infection mediated developmental defects using the C. elegans model

Also, the current work going on in the lab is about studying the developmental defects due to Salmonella infection by using C. elegans as a model system. What severity of the defect Salmonella can cause, as this pathogen is known to infect pregnant women and neonates and lead to preterm birth or even foetal loss. We found that infection has a significant impact on the development of the worm in terms of egg morphology, hatching behaviour, different larval stage development, and even adulthood and gonadogenesis. We are looking out the mechanism of how Salmonella infection can cause these defects.  Salmonella infection is also able to cause the Dauer formation in the worm. We have found that the Salmonella infection can cause the dauer formation in C. elegans, and the phenotype persists up to the 5th generation. Still, beyond that, the worm has adopted itself to eat the Salmonella as their regular food, and no more are responding against the pathogens. 

• Negi VD, Khurana Sandhya and Bonney, Elizabeth, A, “Interleukin-10 Delays Viral Clearance in the Placenta and Uterus of Mice With Acute Lymphocytic Choriomeningitis Virus Infection During Pregnancy” Front. Virol., 15 February 2022
  
• Mallick S, Mishra N, Barik BK, Negi VD, “Salmonella Typhimurium fepB negatively regulates C. elegans behavioral plasticity” J Infect. 2022 Jan 3:S0163-4453(21)00662-9
  
• N. Mishra, S. Mallick, V,D. Negi, "Salmonella Typhimurium infection causes defects and fastening of Caenorhabditis elegans developmental stages", Microbes and Infection, 2021 Oct 28:104894
  
• Pradhan D, Pradhan J, Mishra A, Karmakar K, Dhiman R, Chakravortty D, Negi VD “Immune modulations and survival strategies of evolved Salmonella Typhimurium stains” Biochim Biophys Acta Gen Subj. 2020 Aug;1864(8):129627.
  
• Pradhan, D, Negi VD. “Repeated In-Vitro and In-Vivo Exposure Leads to Genetic Alteration, Adaptations, and Hypervirulence in Salmonella” Microb Pathog. 2019 Nov;136:103654