Professor, Department of Biology
Giacomini, J. J., Leslie, J., Tarpy, D. R., Palmer-Young, E. C., Irwin, R. E., & Adler, L. S. (2018). Medicinal value of sunflower pollen against bee pathogens. Scientific Reports, 8(1). https://doi.org/10.1038/s41598-018-32681-y
Pollinators provide billions of dollars in crop pollination annually, and are critical for preserving plant biodiversity. Concerns about pollinator declines have spurred research into a wide range of stressors, including loss of habitat, pesticide exposure, nutritional deficits, and parasites. Parasites have been implicated in the declines and even disappearance of many bee species, but it may be challenging to identify solutions that reduce bee parasites without reliance on chemicals. With a diversity of challenges, a diversity of solutions will be needed to reverse declines. Governments, industry stakeholders, and the public are now invested in and committed to developing policies that promote bee health, but in many cases we lack solutions that are simple, concrete, and easily implemented. Our research team recently made an astounding and potentially transformative discovery. We found that in the common eastern bumble bee, an abundant native pollinator, sunflower pollen dramatically reduced infection by a prevalent gut pathogen, up to 37 times lower than other pollen treatments. Also, free-flying bumble bee workers collected from farms had lower incidence of infection when there was more sunflower at the farm, indicating the potential for sunflower plantings to reduce infection. Moreover, sunflower pollen may have broad medicinal effects against other bee parasites; we found that sunflower pollen reduced a microsporidian pathogen and Deformed Wing Virus in honey bees in lab trials. These results indicate the exciting possibility that sunflower pollen reduces diverse parasites in multiple bee species, with potential to develop non-chemical pollen supplements as treatments for both bumble bees and honey bees.
Read more about Lynn Adler.
Associate Professor, Department of Biochemistry and Molecular Biology
Joshi, K. K., Bergé, M., Radhakrishnan, S. K., Viollier, P. H., & Chien, P. (2015). An Adaptor Hierarchy Regulates Proteolysis during a Bacterial Cell Cycle. Cell, 163(2), 419–431. https://doi.org/10.1016/j.cell.2015.09.030
The alarming increase in the number of antibiotic-resistant bacterial infections has made the discovery of new antibiotics a critical human health priority. Why have drug resistant bacteria emerged so quickly? One major factor is that all current antibiotics work by killing bacteria completely. While it is true that dead bacteria cannot infect hosts, this approach also creates tremendous pressure for the bacteria to evolve resistance mechanisms. Give that the human microbiome consists of billions of bacteria that are cordially living with their host, it is clear that the problem is not the simple presence of bacteria, but rather certain bacteria in a virulent state. Therefore, a better strategy is to selectively inhibit bacterial virulence, rather than to kill bacteria completely, in order to reduce the pressure to evolve resistance.
All known human pathogens require proteases, which are enzymes that break down proteins, to be infectious. This work focuses on a protease called ClpXP. The bacterium Caulobacter crescentus requires ClpXP when it invades a host as a pathogen, but does not need the protease for regular, non-virulent growth. ClpXP is therefore an ideal target for selective inhibition of bacterial virulence.
This study helps us understand how ClpXP selects certain proteins to break down at certain times. It elucidates the process by which various adaptors work together to select proteins and make them available to the ClpXP, so that ClpXP can destroy them. With this understanding, we can identify ways to block the process. We can also extend the findings in this particular case of C. crescentus to bacteria that pose grave threats to human health, such as Staphyloccus, Vibrio cholera, and Brucella abortus. In addition, because the ClpXP protease in the mitochondria of eukaryotic cells is very closely related to this system, we suspect that our work will inform the growing role of mitochondrial quality control in many human diseases, including cancer.
Read more about Peter Chien.
Associate Professor, Department of Food Science
Yang, T., Doherty, J., Zhao, B., Kinchla, A. J., Clark, J. M., & He, L. (2017). Effectiveness of Commercial and Homemade Washing Agents in Removing Pesticide Residues on and in Apples. Journal of Agricultural and Food Chemistry, 65(44), 9744–9752. https://doi.org/10.1021/acs.jafc.7b03118
Removal of pesticide residues from fresh produce is important to reduce pesticide exposure to humans. This study investigated the effectiveness of commercial and homemade washing agents in the removal of surface and internalized pesticide residues from apples. Surface-enhanced Raman scattering (SERS) mapping and liquid chromatography tandem-mass spectrometry (LC MS/MS) methods were used to determine the effectiveness of different washing agents in removing pesticide residues. Surface pesticide residues were most effectively removed by sodium bicarbonate (baking soda) solution when compared with either tap water or bleach. Thiabendazole, a systemic pesticide, penetrated four-fold deeper into the apple peel than did phosmet, a non-systemic pesticide, which led to more thiabendazole residues inside the apples, which could not be washed away using the baking soda washing solution. To the best of our knowledge, this is the first study that separated the surface and penetrated pesticides in response to washing. It is also the first study that correlated the depth of pesticide penetration and the efficacy of washing. Understanding the effectiveness of various washing procedures in the removal of pesticides on and in apples will allow us to develop better strategies to minimize pesticide exposure from fresh produce. The technique Dr. He developed for detecting pesticide and its penetration has led to an intellectual property disclosure and some industry projects to study pesticides in their formulations and their behaviors. Recently, Dr. He’s lab also helped a company to validate a washing formulation that is based on this study using baking soda. The outcome of this study helps industries to develop more cost-effective and safer pesticide formulations, and cost-effective formulation to remove pesticide residue from food.
Read more about Lili He.
Professor, Francis Chair and Graduate Program Director, Department of Food Science
Sun, Q., Xiao, X., Kim, Y., Kim, D., Yoon, K. S., Clark, J. M., & Park, Y. (2016). Imidacloprid Promotes High Fat Diet-Induced Adiposity and Insulin Resistance in Male C57BL/6J Mice. Journal of Agricultural and Food Chemistry, 64(49), 9293–9306. https://doi.org/10.1021/acs.jafc.6b04322
Application of insecticides contributed to significant increases in agricultural productivity in the 20th century, helping to meet the challenge of feeding the world’s expanding population. However, insecticides are one of the major environmental contaminants, and the extensive use of insecticides has caused wide public health concerns. Simultaneously, emerging evidence suggests that persistent organic pollutants, including insecticides, are linked to the development of obesity and diabetes. Among newly developed insecticides, imidacloprid, in particular, is commonly used to control ectoparasites (i.e. ticks) by direct application to pets, along with agricultural applications. Because of a potential link to the decline of the bee population, usage of imidacloprid in Europe has been banned. This study reports significant off-target effects of imidacloprid and further challenges to determine the synergistic effects of insecticides and other known factors of obesity and Type 2 diabetes. The doses used in the study are low enough to be considered safe in current industrial and regulatory practices. The results of this study may help us understand the current obesity epidemic and will be foundational in developing potential preventive and/or treatment strategy for obesity and Type 2 diabetes in the future.
Read more about Yeonhwa Park.
Assistant Professor, Department of Veterinary and Animal Sciences
Wells, A. C., Daniels, K. A., Angelou, C. C., Fagerberg, E., Burnside, A. S., Markstein, M., Alfandari, D., Welsh, R. M., Pobezinskaya, E. L., and Pobezinsky, L. A. (2017). Modulation of let-7 miRNAs controls the differentiation of effector CD8 T cells. eLife, 6. https://doi.org/10.7554/elife.26398
The immune system is the only known natural mechanism that destroys infected or cancerous cells in an organism. Cytotoxic T lymphocytes, also called T-killer cells, are the most potent killer cells among all of the cells involved in the immune response to viruses and tumors. Unfortunately, under pathological conditions such as chronic viral infections or cancer, the function of T-killer cells is often compromised. When T-killer cells become inactive, it is very difficult to treat these diseases. The Pobezinsky lab is working to understand how to generate and maintain fully functional T-killer cells under pathological conditions.
This study reports the discovery of a molecular switch that turns T-killer cells on or off. The switch is based on certain RNA molecules called microRNA that regulate gene expression. The authors discovered that reducing the expression of a particular microRNA called let-7 results in enhanced T-killer cell function, and conversely, increasing the let-7 expression results in diminished T-killer cell function. Understanding this relationship opens up the possibility for designing therapies that decrease levels of let-7 in order to improve T-killer cell performance in responses to viruses and tumors. Dr. Pobezinsky recently received a large industry grant to directly explore these translational possibilities.
Read more about Leonid Pobezinsky.
Professor, Department of Chemistry
Mout, R., Ray, M., Yesilbag Tonga, G., Lee, Y.-W., Tay, T., Sasaki, K., & Rotello, V. M. (2017). Direct Cytosolic Delivery of CRISPR/Cas9-Ribonucleoprotein for Efficient Gene Editing. ACS Nano, 11(3), 2452–2458. https://doi.org/10.1021/acsnano.6b07600
The recently developed gene editing tool CRISPR/Cas9 is a powerful technology with enormous potential to treat genetic diseases. CRISPR has two components: a scissor-like protein Cas9, and a RNA molecule called sgRNA that guides Cas9 protein to a target gene. Once the Cas9-sgRNA pair gets to the destination gene in the nucleus, it can find and correct the mistakes in the gene with the help of host cell repair machinery. Currently, CRISPR/Cas9 therapy is carried out by delivering genes to the host cells, so that the cells can make their own Cas9 and sgRNA. However, this strategy creates major problems of unwanted gene editing and immune responses because the CRISPR genes remain in the host cells after they are delivered.
This study demonstrates a highly efficient alternative nanomaterial-based strategy that directly delivers a pre-fabricated Cas9:sgRNA complex to the cells. It overcomes the challenges of crossing the cell membrane and arriving at the cell nucleus without being trapped in intracellular structures along the way. The Cas9:sgRNA complex was delivered to >90% of cells using a wide range of cell types. The strategy therefore provides a way to employ the powerful gene editing capabilities of the CRISPR system without suffering from its usual limitations. The research has been patented, and two industrial partnerships have been generated to apply our technology for therapeutic and agricultural use. Additionally, the technology has featured in multiple proposals to funding agencies.
Read more about Vincent Rotello.
M. Sloan Siegrist
Assistant Professor, Department of Microbiology
García-Heredia, A., Pohane, A. A., Melzer, E. S., Carr, C. R., Fiolek, T. J., Rundell, S. R., … Siegrist, M. S. (2018). Peptidoglycan precursor synthesis along the sidewall of pole-growing mycobacteria. eLife, 7. https://doi.org/10.7554/elife.37243
Because it is essential for viability and composed of molecules that are not present in eukaryotic cells, the bacterial cell wall has been a fruitful target of antibiotics. We co-developed a metabolic labeling strategy that has been widely adopted by microbiologists to illuminate cell wall peptidoglycan, a matrix of sugars and non-proteinaceous amino acids. However, while we knew what the probes labeled, we did not understand how they got to their destination. This was a significant limitation, as the uptake pathway of a probe determines whether it is specific for newly-made or newly-remodeled material, categories of peptidoglycan that are inhibited by different classes of antibiotics. In our paper, we determined the metabolic fates of several probes and used this information to pinpoint the location of peptidoglycan assembly and remodeling with precision. This work is an essential first step toward realizing the probes’ industrial applications. For example, well-defined reagents simplify downstream deconvolution of hits from high-throughput cell wall inhibitor screening. As we can attach different cargo to our probes, we also envision using them to deliver antibacterials. The route(s) by which these molecules are likely to access the bacteria is a critical design consideration.
Read more about M. Sloan Siegrist.
Professor, Department of Chemistry
Borotto, N. B., Zhou, Y., Hollingsworth, S. R., Hale, J. E., Graban, E. M., Vaughan, R. C., & Vachet, R. W. (2015). Investigating Therapeutic Protein Structure with Diethylpyrocarbonate Labeling and Mass Spectrometry. Analytical Chemistry, 87(20), 10627–10634. https://doi.org/10.1021/acs.analchem.5b03180
Protein therapeutics are the fastest growing segment of the pharmaceutical industry. Unlike traditional small‐molecule drugs, protein-based drugs must maintain not only their covalent structure (i.e. bonding of atoms in the molecule) but also their proper three‐dimensional (3D) structure. Changes in a protein therapeutic's 3D structure can lead to an inactive drug or worse, an unwanted immune response. Consequently, there is a big push in the pharmaceutical industry to find fast, reliable, and convenient methods to assess protein 3D structure.
While there are excellent traditional biochemical tools that can assess protein structure, they are either too slow to be routinely useful (e.g. NMR, X‐ray crystallography) or they are not sensitive enough to identify structural changes that influence the function of a protein therapeutic (e.g. circular dichroism (CD), fluorescence). Considering this gap in technology, we developed an approach based on chemical labeling and mass spectrometry (MS) that is more rapid and efficient than techniques like NMR and X‐ray crystallography and provides much more structural resolution than techniques such as CD and fluorescence.
The technique described in this paper is the subject of a pending patent, and a company called QuarryBio has recently licensed this technology. We are collaborating with QuarryBio on ways to further extend this method to make it more readily available for pharmaceutical companies to use.
Read more about Richard Vachet.