Tayo Adekeye: Mutations in myosin regulatory light chain protein cause disordered sarcomere assembly in zebrafish muscle
Sarcomeres are the basic contractile unit of muscle, in which myosin-rich thick filaments interact with actin-based thin filaments to generate contractile force. Tightly bound to the head of the myosin heavy chain is Mylpf; a regulatory light chain protein that stabilizes the myosin lever arm and is essential for normal myosin activity. In humans, rare MYLPF gene variants cause a limb contracture disease called Distal Arthrogryposis (DA). However, it remains unclear how these single nucleotide variations impact muscle development and why the human MYLPF variants cause DA. In this brief talk, I will discuss how two MYLPF variants from DA patients (with residue change G163S and C157F) failed to rescue the sarcomere in zebrafish mylpfa knockout, suggesting that a sarcomere assembly defect underpins Mylpf-induced DA. Also, when expressed in wild-type animals, the recessive variant (C157F) looks normal, while the dominant variant (G163S) induces severe sarcomere defects, recapitulating the human inheritance patterns. These findings reveal a vital role for Mylpf in sarcomere assembly in vertebrates and suggest a mechanism for the muscle defect in DA.
Tayo is a 3rd-year PhD student in the Talbot lab with a background in microbiology (B.S) and Human and Population genetics (M.S). His Ph.D thesis focuses on investigating the molecular basics of muscle formation and development, and the implications for human musculoskeletal disease. He uses genetic and molecular techniques and live imaging approach in Zebrafish to study the interaction of sarcomere protein during muscle formation and the mechanism of the disease associated with impaired sarcomere organization.
Vendy Hazuková: Consequences of ice-out timing variability for physical and biogeochemical structure of
small, Arctic lakes in West Greenland
Abrupt warming in West Greenland has shifted the average timing of lake ice-out 6 days earlier since the early 1990s; however, there remains large variability in its timing, with up to 30-day difference in ice-out date across years. We found that in early ice-out years, summer (June and July) mixing depths were deeper and lake-bottom
temperatures were warmer. On the other hand, surface temperatures were quite variable across lakes along the ice-out gradient. The differential responses of surface and lake-bottom temperatures to inter-annual variability have further implications for ecosystem processes in these lakes. For example, lakes with propensity to incomplete
mixing in late ice-out years tend to mix fully in years when ice-out occurs earlier during the year. Consequently, summer hypolimnetic concentrations of dissolved oxygen are higher despite warmer temperatures. These findings demonstrate the necessity to parse out different climatic drivers to better understand how thermal structure and lake ecosystem processes respond to ongoing and future changes.
Vendy is a 5th year PhD Candidate in EES working with Dr. Jasmine Saros. Her dissertation is focused on understanding how Arctic lakes respond to climate change.
Shehnaz Munnaf Chowdhury: Assessing overwintering of Ganaspis brasiliensis
In Dr. Fanning’s lab, Shehnaz is assessing the ability of G. brasiliensis to survive the winter in the northern temperate climate conditions of Maine, New York, and New Jersey as well as determining the survival and impact of nutrition of G. brasiliensis in laboratory bioassays. To assess the ability of G. brasiliensis to survive the winter in the northern temperate climate conditions of Maine, New York, and New Jersey, they will conduct survival trials in both the laboratory and field. In both trials, they will test diapausing prepupae and adult life stages that have been acclimated to the cold and others have remained non-acclimated.
Shehnaz is a 1st-year Master’s student of Entomology in the School of Biology, working as a graduate research student in Dr. Philip Fanning’s lab. She completed her Bachelor of Science in Agriculture and her first Master’s in Entomology from Bangladesh Agricultural University.
Stephanie Hurd: The effect of landscape fragmentation on Ixodes scapularis densities through altered small mammal behavior and their predators’ activity
Extensive research examined the impacts of forest fragmentation on the blacklegged tick (Ixodes scapularis), the vector of Lyme disease in the northeast United States, but studies’ results are conflicting and underlying mechanisms remain understudied. There has been limited investigation into the cascading effects of fragmentation on population size and behavior of small mammals that provide blood meals for I. scapularis and are reservoirs for the causative agent of Lyme disease, Borrelia burgdorferi. Fragmentation may reduce the activity of predators of small mammals (e.g., bobcats, foxes, etc.), releasing their prey (e.g., mice, etc.) from the threat of predation, thereby increasing prey foraging, tick-host encounter rates, and thus tick densities. Additionally, fragmentation increases forest edge, a preferred browsing habitat of deer, which are important hosts for adult I. scapularis. This study tests the hypotheses that fragmentation results in higher tick densities through (1) decreased predator activity, (2) increased prey foraging, and (3) increased deer activity. We selected 20 sites, each 1km2, in southern Maine, an area with a high incidence of tick-borne disease. These study sites ranged along gradients of multiple fragmentation metrics (e.g., patch size, isolation, etc.). We used drag sampling to collect ticks and determine tick densities at each site. To quantify the activity of small mammals, their predators, and deer, we deployed trail cameras to estimate the relative abundance of predators and deer and used foraging trays to assess small mammal foraging behavior. Preliminary results suggest higher tick densities at intermediate levels of fragmentation.
Stephanie is a PhD candidate in Dr. Allie Gardner’s lab, studying the effects of forest management practices across spatial scales on wildlife communities and the transmission of tick-borne pathogens.