How Ontario is battling a very hungry caterpillar

A recent interview of yours (among other scientists) truly with TVO's Justin Chandler

Gypsy-moth caterpillars are killing trees throughout the province. This research team thinks understanding how they pee could help defeat them.

Op-ed in Canadian media outlets about our research

I recently wrote an op-ed describing our research spanning 2018-2020 - start here to understand why we study caterpillar "kidney" and follow links in the article to peer-reviewed publications to read detailed peer-reviewed studies.

Voltage-gated, ligand-gated and mechanosensitive ion channels regulate ion transport in (non-excitable non-contractile) epithelia

Upcoming research program at California State University San Marcos

Epithelia are built for unidirectional ion transport. Many epithelia, including Malpighian tubule epithelia of caterpillars are not able to contract and are not innervated. Recent work from our lab demonstrated that Malpighian tubules of caterpillars express voltage-gated, ligand-gated and mechanosensitive ion channels. Subsequent work has shown that this previously unaccounted for molecular machinery is used to regulate ion transport in the Malpighian tubules of caterpillars. Why do Malpighian tubules need to do this? Caterpillars are voracious eaters and many species grow ~1,000-fold within 4-5 weeks. This puts pressure on their kidney to constantly excrete metabolic wastes. Caterpillars have adapted for this by embedding their Malpighian tubules into the rectal complex, which enables them to use ions and water from the diet instead of their haemolymph (blood) to power excretion in their kidney. However, caterpillars eat gargantuan amounts of food, but there are periods when they're not teaching (e.g., moulting). Under these circumstances, they cannot use the dietary ions and water to power their kidney. Instead, they switch to using ions and water from the blood. All evidence to date suggest that voltage-gated, ligand-gated and mechanosensitive ion channels play a role in this ability of the caterpillar Malpighian tubules to switch between using haemolymph ions and dietary ions. Why do they need voltage-gated, ligand-gated and mechanosensitive ion channels to do this? Because this switchover takes place within minutes! This enables the caterpillar to keep its excretory function unperturbed in the face of changing dietary ion availability.  

Gap junctions in ion-transporting epithelia

Current post-doctoral work with Dr. Michael J. O'Donnell (McMaster University)

This series of studies is focussed on establishing the role of gap junctions in vectorial ion transport in vertebrate and invertebrate epithelia. Click on the link below to read an article describing our recent discovery of how gap junctions enable ion transport in the Malpighian tubules of insects.

Ion transport mechanisms in the Malpighian tubules of the larval cabbage looper 

Trichoplusia ni

Current post-doctoral work with Dr. Michael J. O'Donnell (McMaster University)

Several studies aimed at determining the molecular machinery of ion transport in the Malpighian tubules of T. ni. We are aiming our studies at understanding how the paradoxical reabsorption of cations is enabled through the secondary cells of T. ni. Additionally, of special interests is the segmented nature of the Malpighian tubule of larval lepidopterans and its ability to change between ion secretion and reabsorption depending on the hydro mineral status of the animal.

A role for tight junctions in regulating paracellular permeability of the fish gill epithelia

Doctoral work under Dr. Scott Kelly's supervision (York University)

The tight junction (TJ) complex is a cellular structure that is common to all vertebrate epithelia. Molecular constituents of the TJ complex dictate paracellular permeability properties of the tissue by occluding the intercellular cleft between adjacent epithelial cells. The bicellular TJ (bTJ) complex lines the border between two adjacent epithelial cells and is credited with fine-tuning epithelial barrier properties in aquatic vertebrates. The molecular components of the bTJ in fishes include a large superfamily of claudin (Cldn) proteins. Aquatic vertebrates, and fishes specifically, rely on the TJ complex in epithelia exposed to surrounding water to battle passive ion loading and ion loss. In the current set of studies, potential roles of individual TJ proteins in the establishment and maintenance of the barrier properties in rainbow trout gill epithelium were investigated in vivo and in vitro. Tricellular TJ (tTJ) is found at the point of contact between three adjacent epithelial cells. Very little is known in regards to the tTJ complex in the fish epithelia. Part of the studies concentrated on identifying and characterizing the molecular components of the bTJ and tTJ in an ancient jawless vertebrate sea lamprey, Petromyzon marinus. Genes encoding for several TJ proteins were identified in the sea lamprey genome and their function studied. Altogether, the current collection of studies has provided a significant insight into the function of bTJ and tTJ proteins in aquatic vertebrates. 

(760) 750-3400 x8046

Dept. of Biological Sciences
CSU San Marcos
333 S. Twin Oaks Valley Rd. 
San Marcos, CA 92096

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©2018 by Dr. Dennis Kolosov, comparative electrophysiologist. Updated in 2020.
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