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K-State Today

October 24, 2023

Sujata Chaudhari to present Biochemistry and Molecular Biophysics Seminar

Submitted by Biochemistry and Molecular Biophysics

Sujata Chaudhari, professor of pathology and microbiology at the University of Nebraska Medical Center, will be the featured speaker for this week's Biochemistry and Molecular Biophysics Seminar. Chaudhari will present "Shaping the Shield: Exploring Tick Cuticle Remodeling" at 4 p.m. Wednesday, Oct. 25, in 120 Ackert Hall.

The black-legged tick, Ixodes scapularis, is a common vector for multiple human pathogens, including Borrelia Burgdorferi, the etiological agent of Lyme disease. Ticks have four developmental stages: egg, larvae, nymph and adult. Once hatched from an egg, the tick must ingest a substantial blood meal before it can molt and transition to the next developmental stage in its life cycle. Unfortunately, the large blood meal also increases the chance of pathogen transmission from an infected host. Blood feeding in ticks is characterized by an expanding cuticle that allows them to engorge and reach sizes up to 100 times their original body weight. However, the ultrastructural changes that underlie cuticle expansion and the factors that stabilize the expanding cuticle against the increasing turgor pressure arising from the ingested blood meal have not been thoroughly studied.

We hypothesize that chitin, a structural component of the tick cuticle, undergoes remodeling to stabilize the expanding cuticle and accommodate the internal hydrostatic pressure. Chaudhari's lab's data indicates that exocuticular chitin is degraded during cuticle expansion while new layers of chitin are added to the endocuticle. The synthesis of chitin outside of molting stages has not been previously reported.  Chaudhari's lab's data, for the first time, reveals a novel phenomenon of biphasic chitin synthesis in ticks. The lab's ultrastructural and confocal microscopic analysis of the nymphal tick cuticle during the blood-feeding and molting stages demonstrates that chitin is synthesized in two separate phases. Additionally, the lab's data highlights a direct impact of inhibiting chitin synthesis on tick feeding. The lab's work aims to shed light on the molecular mechanisms of cuticular chitin remodeling in ticks and, in the long term, assess the importance of chitin metabolism as a target for novel vector control strategies.