Doug Sweeney is a fourth-year PhD student majoring in marine biology at Scripps Institution of Oceanography at the University of California San Diego. His research focuses on natural products discovery and chemical ecology, and he’s currently working at the Center for Biotechnology and Biomedicine (CMBB) under the guidance of Scripps microbial ecologist Paul Jensen. A native of Southern California, Sweeney attended Grossmont Community College in El Cajon before transferring to UC San Diego, where he earned his Bachelor of Science in microbiology, magna cum laude. Sweeney had worked at his family’s business for 10 years before finding his own path at Scripps.
explorations now: Why did you choose to attend Scripps?
Doug Sweeney: Through my undergraduate experience at UC San Diego, I attended a variety of microbiology courses, some at Scripps, and developed a strong interest in marine microorganisms, specifically their ability to produce antibacterial and anticancer compounds. Additionally, Scripps has esteemed faculty and researchers in the field of natural products research. These include Dr. William Fenical and my advisor, Dr. Paul Jensen, who together discovered the potent anticancer compound salinosporamide, or marizomib, a molecule currently in phase three clinical trials as a treatment for glioblastoma, an aggressive type of cancer that can occur in the brain or spinal cord.
en: What are you researching at Scripps and how did you become interested in this field?
DS: My research involves looking into antibacterial compound production by marine bacteria. Today, over half of the antibiotics in use are derived from naturally occurring compounds from bacteria. Despite the discovery of hundreds of these compounds, we still do not know why most of these organisms produce them! My research focuses on understanding the ecological role (e.g., species interactions) of these molecules to facilitate future drug discovery.
en: What’s life like as a Scripps student? Describe a typical day.
DS: The balance of wet and dry lab work is my favorite part about researching as a Scripps student. On a typical day, I try to spend my mornings catching up on computer work (everything from analyzing data to ordering supplies) and preparing lab work for later in the day. I really love working in the lab, spending my afternoons culturing bacteria from marine sediments and analyzing the compounds that they make. Often, these organisms produce brilliantly colored pigments and I try to correlate these beautiful colorations to compounds or antibiotic activity. But the part I love the most about Scripps is being so close to the ocean, where I can surf as a reward for finishing my lab work for the day!
en: What’s the most exciting thing about your work?
DS: While antibiotic discovery is an amazing aspect of my work, these microbial compounds may have surprising consequences for global biogeochemical cycles, such as carbon and iron cycling. For instance, some bacteria can use these compounds to “breathe” iron oxides (rust!). If we were to imagine this process on a human scale, it would be like exhaling onto a baseball and throwing it at a boulder in order to breathe! These extraordinary physiological adaptations not only allow for survival in these environments, but contribute to the global iron cycles by freeing up limited iron reserves for use by marine plants and algae. This is coupled with the decomposition of hard-to-digest organic matter, further adding to the marine carbon cycle. Really makes you think how a microscopic organism can have such a huge impact.
en: Are there any role models or mentors who have helped you along the way?
DS: I cannot thank my advisor, Dr. Paul Jensen, enough for allowing me to join his lab and allow me to pursue my research interests. His mentorship and guidance have been invaluable to my time at Scripps. There are also so many people in the natural products groups here at Scripps whom I admire who have helped me during my time. But without Professors Bianca Brahamsha and Brian Palenik, who instilled my love for marine microbiology back in undergrad, I would not have applied to Scripps.
en: What are some of the challenges you face as a student?
DS: Recently the obvious answer here is COVID-19. Despite the obstacles it has presented for myself, the research community at Scripps, and the world as a whole, it has been amazing to see the Scripps community come together: faculty, students, and administrators alike to keep our institution running. I cannot thank everyone enough for all their great work. While research has slowed, due to everyone’s amazing efforts, we have not stopped.
en: What are your plans post-Scripps?
DS: While I have not made concrete plans for life after Scripps, I have been considering staying in academia with the hopes of eventually running my own research group. As a stepping stone to possible professorship, it would be wonderful to give back to the community college system that inspired and pushed me to get to where I am today as an instructor.
Undergraduate student examines red blood cell activity in teleost fish