Ticks are vectors for several serious diseases (meaning that they can transmit these diseases to humans), including Lyme disease, babesiosis, and anaplasmosis. Melissa Yost-Bido ’19 studied something called Haller’s organs: chemosensory organs (essentially, a very special type of smell) that ticks have on their front legs, and that is thought to help them detect pheromones, carbon dioxide, and infrared radiation. As you can guess, all that ticks really care about, is how to find a host (such as a mouse, or a human), to attach to them, and feed on their blood. Being able to detect animal smells and heat would definitely help here!
Many methods of tick-borne disease prevention that are used now, harm not only ticks, but also other, good, beneficial organisms. If we learn more about the Haller’s organ, we can try to find new ways to fight ticks, by making sure that they cannot find new hosts. Melissa studied the ability of the Haller’s organ in blacklegged ticks (Ixodes scapularis; the nastiest ticks around here) to detect infrared light. She collected local ticks, separated them into groups, and then either left their Haller’s organs intact, or removed them. Then Melissa exposed each tick from each group to infrared light (heat), and recorded the distance that each tick moved towards the source of infrared radiation. She found that ticks with a Haller’s organ traveled farther towards the heat, compared to those that had their Haller’s organs removed. This suggests that Ixodes ticks can use Haller’s organs to detect warm bodies, which is something nobody had ever shown before!
We live in the era of antibiotic resistance: old, familiar antibiotics, that used to work so well in the past, are no longer guaranteed to kill harmful bacteria, as the bacteria evolve new ways to fight back and survive the treatment. Because of that, now, more than ever, it is important to study the fundamentals of gene regulation in bacteria, with a hope to find new ways to control them.
Riboswitches are a unique mechanism of gene regulation that is used by bacteria, fungi, and plants. A piece of RNA with a riboswitch changes its shape depending on what chemicals are present in the cell, which in turn changes what proteins are produced by the bacterium. Riboswitches were shown to be critical for the bacterial survival, which means that in the future, we can try to use them as targets for the development of new pharmaceuticals. With the guidance from Dr. Gabriel Perron and Dr. Swapan Jain, Rachael Mendoza ’19 used bioinformatic tools to identify and classify the riboswitches in thirty strains of a certain bacterial species (B. subtilis). She described the diversity of riboswitches in these strains, and put forth some interesting hypotheses about how this information can inform development of future medical treatments.
For her senior project, Lucy Christiana ’19 built a computer simulation of plant community dynamics. Lucy studied how plants would grow if they experience a phenomenon called “plant-soil negative feedback”. Despite a scary name, the idea of this effect is rather simple: imagine that every growing plant is attacked by some “bad stuff” living in the soil, such as pathogenic fungi that try to weaken or kill the plant. As a plant is growing , these fungal pathogens will multiply in the soil around it, making this patch of soil kind of hostile to this plant species. Any seed from this species, for example, will have a hard time surviving in this particular patch of soil, just because it is so rich with “bad fungi”. A different plant species, however, will have no problem living there, as it will be immune to pathogens (each plant species comes with its own list of enemies, so pathogens of one species don’t necessarily harm the other).
As you can imagine, this can really change how plants grow, and it would probably improve biodiversity: even if one plant species is a strong competitor, it will soon be weakened by local pathogens, allowing other species to grow in its place. Lucy was interested in how these negative feedbacks shape the emerging plant community, and she used over 30 years of historical vegetation data from a particular long-term field experiment in Lawrence, Kansas. Lucy built a cellular automata model for one of the species described in this experiment (Ambrosia artemisiifolia, aka common ragweed), and compared predictions of her model to real data. This study is a step towards a more integrated analysis of spatiotemporal patterns of plant community assembly dynamics, and it can help us to understand how plants interact with each other, and how these interactions shape the landscapes that surround us.
In recent years, many have speculated that climate change is the driving force behind the spike in cases of Lyme disease in the northeastern United States. It would be really useful for the public if we could use climate data to predict places and times at risk for Lyme disease. In her senior project, Sarah Weiner used public records from the United States Drought Monitor to create a climate index. Then, with guidance from professor Felicia Keesing, Sarah built statistical models to see whether this climate index could be used to predict year-to-year variation in Lyme disease incidence at the county level. Sarah found that climate is not a practical way to predict Lyme disease outbreaks, and that other factors, such as location, are much better predictors.
In her senior project, Biz Osborne-Schwartz’ 17 sought to improve oral rehydration therapies (ORT) for cholera patients. Working with her advisor, Professor Brooke Jude, Biz developed a protocol to study the attachment of Vibrio cholerae to chitin (a stand-in for a human intestinal cell) and other carbohydrates. This new protocol allowed her to test if adding a certain type of chemical compounds, called enzyme resistant carbohydrates, to ORT could decrease the number of bacteria in a patient infected with cholera. Biz observed a decrease in Vibrio cholerae attached to chitin beads when incubated in ORT with enzyme resistant starches, which means that more complex ORT are promising for cholera patients!
In November 2017, Bard alum Silas Busch ’16 presented the work he did during his Bard senior project at a professional society meeting “Society for Neuroscience” in Washington DC. His poster won a travel award from the David Hubel Memorial Fund (distributed through the Faculty for Undergraduate Neuroscience society).
In his work, Silas studied how neural cells in the brain of frog tadpoles change their spiking properties when tadpoles experience different types of visual and auditory stimuli. To measure neuronal properties, Silas used a fancy electrophysiological technique, called Dynamic Clamp. He found that neurons become tuned to better process stimuli perceived by the brain, and that when visual and auditory stimuli are combined, it leads to interesting, and somewhat unexpected changes in neuronal tuning.
Presentation info: S.E. Busch, A.S. Khakhalin. Midbrain neurons show temporal retuning of intrinsic properties in response to patterned uni- and multisensory stimulation. Wed Nov 15, 2017. Washington DC.
In her senior project, Daniella Azulai ’17 studied antibiotic resistance of a bacterium Pseudomonas aeruginosa: a pathogen that plagues patients with compromised immune systems and people with cystic fibrosis. Daniella developed a new method to test how virulent (harmful) different strains of these bacteria are. Using larval zebrafish, she found that antibiotic resistance does not necessarily correlate with virulence, but rather that each strain showed a unique profile, pointing to differences in the evolution of these strains over time.
Sydney Pindling finished her senior project in the fall of 2016, under the supervision of professor Gabriel Perron. Sydney developed a promising new model to study the effects of antibiotics, such as streptomycin, on the animal microbiome. She exposed larval zebrafish (Danio rerio) to very low concentrations of streptomycin; in fact, the concentrations Sydney used were similar to that observed in in environment: rivers and streams near human settlements. Sydney found that that even at these low concentrations streptomycin changed the microbiome in the larval fish, and increased larva mortality. She also observed that the microbes in the fish gut were selected for genes associated with antibiotic resistance. These results may have relevance both for studies of antibiotic effects in humans, and for the environmental research of fish populations.
Biology senior Molly McQuillan and professor Arseny Khakhalin coauthored on a neuroscience paper published in the prestigious life sciences journal eLife. The paper presents new research that explains how the developing brain learns to integrate simultaneous sensory cues—sound, touch, and visual—that would be ignored individually.
Read full press-release from Bard
Full citation: Truszkowski, Torrey LS, Oscar A. Carrillo, Julia Bleier, Carolina Ramirez-Vizcarrondo, Molly McQuillan, Christopher P. Truszkowski, Arseny S. Khakhalin, and Carlos D. Aizenman. “A cellular mechanism for inverse effectiveness in multisensory integration.” eLife 6 (2017): e25392.
This amazing photo of a Snow Leopard (Panthera uncia) was made by Bard biology senior Devin Fraleigh, who is now working with Panthera foundation, in collaboration with the American University of Central Asia in Kyrgzstan, to study populations of Snow Leopards in the Tien Shan mountains. This image of an adult leopard was captured using an automated camera in early March 2017 on a mountain pass in the Ala-Too mountain range, not far from Bishkek.