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.
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.
For her senior project Martie studied the behavioural response in captive common marmosets (Callithrix jacchus – the second smallest primate in the world) to the introduction of a novel foraging-enrichment device. In captivity, animals often become bored, depressed, or stressed, and enrichment is a way in which caretakers can improve the lives of captive animals. Compared to many other animals, monkeys are very smart, and therefore need even more stimulation to keep them physically and psychologically active. Knowing how to keep animals happy and healthy in captivity is a highly important aspect of conservation biology.
In the wild, marmosets don’t just collect fruits and insects like many other monkeys do, but gouge trees with their teeth and suck out the sap. In captivity however, most monkeys are fed fruits and vegetables from stationary bowls, which provides enough nutrition, but gives no practice in natural ways foraging, and makes the marmosets lose their ability to gouge trees. With the help of Bard professor Felicia Keesing, Martie designed a novel enrichment device for captive marmosets living in captivity in Costa Rica. The device was made of a small wooden log with holes drilled all around it, that Martie filled with honey and hang up vertically in the cages. This study was the first ever to try honey as a sap substitute for common marmosets, and Marite found that this simple device increased positive foraging behaviours and decreased inactivity, significantly improving the well-being of captive monkeys.
Shailab Shrestha studied how bacteria develop resistance against antimicrobial agents, such as antimicrobial peptides. Together with prof. Gabriel Perron, Shailab sequenced genomes of several experimentally evolved Pseudomonas fluorescens populations resistant to high concentrations of a certain synthetically modified antimicrobial peptide named pexiganan, and compared these genomes to each other. The results of his original studies were not quite clear due to possible contamination, but Shailab followed up on them during BSRI 2016, and the project has high chances of being eventually published as research paper.
In her senior project, Katherine Moccia studied potential effects hydraulic fracturing (aka fracking) can have on microbial communities in streams near fracking sites. Under supervision of prof. Brooke Jude, Katherine tried to understand whether the presence of bacteria that produce purple pigments, such as species of Janthinobacterium, can be used as an indicator for the overall “health” of a natural water stream. She used microbial isolates from a local creek, and added a commonly used hydraulic fracturing material called glutaraldehyde to simulated microbial communities, to quantify the effects glutaraldehyde would have on the number of purple colonies. The results of this project were not quite clear, but are promising methodologically.
Many aquatic insects use polarized light to find water surfaces on which they reproduce, and where their larvae live and grow. Manmade objects and structures can sometimes mimic these water surfaces by polarizing light. Moreover, in some cases they can be more attractive to aquatic insects than water itself. This effect causes “ecological traps” that can lead aquatic insects to population decline or even extinction.
Previous studies have shown that the attractiveness of polarizing synthetic surfaces can be reduced if grids of non-polarizing lines are strategically placed on them. In his senior project, Theodore Black measured the effect of line thickness on the attractiveness of polarizing non-water surfaces. Early in the morning he would install his polarizing traps near the water stream, and late at night he would collect them. Then, for days and days, he would sort and identify insects trapped in oil under the microscope, classifying them into such poetically named groups as non-biting midges (Chironomidae), black flies (Simulliidea), caddisflies (Trichoptera), and mayflies (Ephemeroptera). This work allowed Theo to analyze and describe the effect of non-polarizing line thickness on the attractiveness of traps, which will help to protect aquatic insects from human interference. Using this new information, engineers will be able to design solar panels that are efficient, yet don’t trick aquatic insects into laying eggs on it, helping them to avoid an evolutionary trap.
The Steven & Alexandra Cohen Foundation has awarded a $5 million dollar leadership grant to support a scientific study that seeks to reduce Lyme disease in neighborhoods. If successful, the project will revolutionize Lyme disease prevention.
Bard College biologist Felicia Keesing and Cary Institute disease ecologist Richard Ostfeld will direct the scientifically rigorous five-year study. It will take place in Dutchess County, New York, which is home to one of the nation’s highest Lyme disease infection rates. Residents of 24 neighborhoods will be recruited from Lyme disease hotspots identified by the researchers and their partners at the Dutchess County Department of Health.
Link to the project web-page:
What are the molecular processes distinguishing cell regeneration from cell development? Using zebrafish as a model organism, Sophia Zega studies one facet of this question by investigating the role of FAT2 protein in initial hair cell development, and in hair cell regeneration. Based on previous evidence we know FAT2 levels increase following hair cell ablation in preparation for regeneration. Sophia performs a knock down of FAT2 in zebrafish larvae, and then stains hair cells with dyes binding to actin and microtubules, to see how the FAT2 gene is important for hair cell development and regeneration.