Many eukaryotes, pathogenic and free-living alike, encyst during their life cycle. How these various organisms sense their environment to determine when and where to differentiate is largely unknown. Our recent work on the intestinal parasite Giardia lamblia has demonstrated that intestinal bile and elevated pH deplete cholesterol rich lipid rafts from the parasite plasma membrane which upregulates cyclic adenosine monophosphate (cAMP) production and initiates encystation. I will present our recent work on the regulation of encystation in Giardia.

Biodiversity is uneven both across geographic regions and branches of the tree of life. In this talk, I will explore one possible cause for this pattern: variation in the rate at which new species form. Using a data set from lizards and snakes, I will discuss the possible factors influencing speciation rate variation.

Note: this talk was not recorded at the request of the speaker.

Basic scientific research is often geared towards the biology of humans or more experimentally tractable organisms that share biology with humans. However, evolution has run many experiments distinct from human biology resulting in groundbreaking innovations (CRISPR, GFP, PCR, optogenetics and many more). Here, I will highlight how studying a broader range of organisms can shift our understanding of the rules of life and impact our ability to engineer it.

The plant immune system recognizes pests and pathogens and activates inducible defense responses. Our lab aims to understand how plants detect and respond to different classes of attackers, and how plants recognize the huge breadth of potential threats through a limited number of receptor-encoding genes. Our lens on immune recognition is to study the large set of several hundred receptor kinases, which can specifically bind diverse pest-associated molecular patterns (PAMPs).

Our intestinal microbial community is quickly evolving with us, following changes to modern lifestyles and even throughout our lifetimes. I aim to understand how horizontal gene transfer shapes interactions in the microbiota and the implications of this pervasive phenomenon for community properties relevant to human health (e.g. resilience of a healthy microbiota to perturbations). I identified a large conjugative plasmid that frequently transfers to multiple species within a person and mediates the formation of multi-species biofilms.

Mammals maintain stable body temperature largely independent of the temperature of their environment and even small deviations from optimal internal temperature can threaten their survival. Thermoregulation critically depends on the ability to sense deep body temperature by the intrinsically warm and cold-sensitive neurons in the preoptic area of the hypothalamus (POA). However, the precise physiological roles of the temperature-sensitive POA neurons and the molecular mechanisms responsible for their temperature sensitivity are poorly understood.

Several disease-causing bacteria produce toxins that damage host cells by triggering preprogrammed cell death. Two such bacterial toxins are called cytolethal distending toxin B and apoptosis-inducing protein of 56 kDa. We discovered that diverse insect species co-opted the two bacterial genes encoding each cytotoxin through a phenomenon called horizontal gene transfer (HGT). HGT occurs when a gene from one organism is inserted into the genome of another and then is stably inherited across generations.

Osmoregulation and ion regulation are essential features for normal physiological functions in animals. Using integrative approaches to describe coordinated cellular and organ-level mechanisms with physiological traits, my research broadly examines fundamental features that allow invertebrate animals to adapt to fluctuating environmental conditions. My talk will focus on work examining the interplay of anthropogenic disturbances and ion regulation in two different arthropod groups, amphipods and mosquitoes.