SAN GABRIEL MALL and LIBRARY

Science Lecture Series Schedule

Sponsored by William Gohlke, in memory of OLE W. GOHLKE and STEPHANNE A. GOHLKE

Science Lecture Series Spring 2025

Science Lecture Series May 29, 2025 event flyer

Warming boosts the prevalence of antimicrobial resistance in soil bacteria: A case study and synthesis

Melanie Hacopian
Ecology and Evolutionary Biology at UC Irvine

Thursday May 29, 2025, 12:30pm-1:30pm, CS 177

Abstract:
The effect of warming on antimicrobial resistance (AMR) genes in the environment has critical implications for public health but is little studied. AMR mechanisms may be favored at warmer temperatures as heat, desiccation stress, and antimicrobial compounds sometimes impose similar consequences on bacterial cells. We collected published soil bacterial genomes from the BV-BRC database and tested the relationship between reported optimal growth temperature and the number of encoded AMR genes. Furthermore, we tested the relationship between temperature and AMR gene transcription in a natural ecosystem by analyzing soil transcriptomes from a warming manipulation experiment in an Alaskan boreal forest. We hypothesized that there is a positive relationship between warming and AMR prevalence in gene content in bacterial genomes and transcriptomic sequences, and that this effect would vary by drug class. Regarding the bacterial genomes, we found a positive relationship between the fraction of encoded AMR genes and the reported optimal temperature of soil bacteria. The drug classes tetracycline and lincosamide/macrolide/streptogramin had the strongest positive relationship with reported optimal temperature. For the case study in a natural ecosystem, we found 61 significantly upregulated AMR gene-associated transcripts spanning eight drug classes in warmed plots. In the Alaskan soil samples, we found that warming elicited the strongest positive effect on transcripts targeting lincosamide/streptogramin, beta-lactam, and phenicol/quinolone antibiotics. Overall, higher temperatures were linked to AMR gene prevalence.

Bio: Melanie Hacopian graduated from Glendale High School then went to Pasadena City College, where she joined her first research lab under the mentorship of Dr. Jared Ashcroft. Melanie transferred to California State University, Long Beach where she first learned about the field of environmental microbiology in Dr. Renaud Berlemont's bioinformatics lab. During the last year of her undergraduate education, she applied to Ph.D. programs and was accepted to UC Irvine in the Department of Ecology and Evolutionary Biology. Working in Dr. Kathleen Treseder's global change lab, Melanie has the opportunity to study the response of soil microbial communities to warming and drying in natural settings.

Past Lectures
2/27/24: Mud matters: Understanding the role of ocean sediments in storing carbon
3/26/24: Bound for Glory
4/30/24: Various Population of Mitochondria & Their Role in Disease
5/28/24: Healthcare Professions Internship
9/18/24: From Molecular Gastronomy to Drug Delivery
9/24/24: Age-related decline in progenitor differentiation potential may reduce skeletal muscle regeneration
10/22/24: My Non-traditional Pathway Into Medicine: from post-civil war El Salvador to Glendale Community College to medical school
11/27/24: Mathematics in Antiquity: The Art of Calculation in the Ancient World
2/25/25: Mendel’s Seeds of Genetics: From Brno to the World
3/27/25: U.S. Mendel School at GCC Announces the Mendel Contest: How do I see Mendel?
3/37/25: What causes severe morning sickness: using genetics to solve an unmet need in women’s health
4/29/25: From GCC to Colorectal Surgery