Environmental Science Student Krystalle Diaz

Krystalle Diaz is an Environmental Science student working on her undergraduate Honors College thesis in Dr. Jean McLain’s lab in the Department of Soil, Water and Environmental Science (SWES), in collaboration with Dr. Virginia Rich.  Krystalle joined Dr. Rich’s lab as an undergraduate technician in the summer of 2013 after her sophomore year of study, and stayed on to do cutting-edge research on the response of permafrost microbial communities to ecological change using metaproteomic analyses.  She received funding to present results at the American Society for Microbiology in May 2014 as part of their Undergraduate Capstone Fellowship Program, and she presented again at the American Geophysical Union last December.  After Dr. Rich announced her departure from the University of Arizona to join the faculty at Ohio State University, Krystalle became interested in working with Dr. McLain after attending an informational session featuring Honors College faculty mentors in SWES. 

Dr. McLain’s research is focused on the environmental safety and public health impacts of using reclaimed wastewater for crop and turf irrigation, questions that take on additional significance under conditions of overallocated water supplies in the Southwestern United States.  A significant unanswered question is whether trace contaminants (including residual antibiotics) in the wastewater can have detrimental effects on the environment.  Krystalle is examining the presence of genes encoding antibiotic resistance in the same permafrost soils she worked on with Dr. Rich.  Antibiotic resistance is known to be naturally-derived and occurs in pristine soils, but what kinds of resistance are common in natural habitats, versus what is common in clinical settings, and the respective levels of resistance, are poorly understood.  Krystalle is using a bioinformatics approach, mining peat soils for antibiotic resistance genes present in the collective genetic information of all microorganisms in the peat soil community (metagenomics).  While there have been other studies looking for antibiotic resistance genes in the environment, Krystalle is moving beyond simply looking for overall sequence similarities, instead building models of the variable and conserved regions of known antibiotic resistance genes and using those models to screen the communities’ genes for functionally similar matches.  This allows more robust identification of potentially quite divergent “wild” versions of antibiotic resistance genes in these Arctic peat soil communities.




After graduating from the University of Arizona this coming December, Krystalle will begin a Master’s program in Microbiology at the University of New Hampshire in the New Year. There she will build upon the conceptual approaches and methods she has trained in during her undergraduate research. 

This spotlight was contributed by

Krystalle S. Diaz