Lab Members

Principal Investigator

Karen Ottemann, Ph.D. Karen grew up in Michigan and Illinois before landing in the San Francisco Bay area in 7th grade. She received her B.S. in Bacteriology from UC Davis in 1987, worked for almost a year at Cetus Corporation, and then carried out Ph.D. work on the Vibrio cholerae virulence gene regulator ToxR at Harvard University in the Microbiology and Molecular Genetics Department with Prof. John Mekalanos. After finishing her Ph.D. in 1994, she moved to UC Berkeley Molecular Cell Biology Department to work on Salmonella chemoreceptors with Prof. Daniel E. Koshland, Jr. from 1994-1999. In 1999 she started her own lab at UC Santa Cruz focussed on colonization abilities and chemotaxis of Helicobacter pylori. She enjoys the collegial atmosphere and amazing research done by her colleagues, as well as the many gorgeous campus hiking and biking trails.


Lab Members

Xiaolin Liu, Ph.D.

Post doc Xiaolin grew up in the beautiful Shandong Peninsula between the Bohai Sea and Yellow Sea. He completed his Ph.D. work on Azorhizobium caulinodans chemotaxis in 2021 from the University of Chinese Academy of Sciences (UCAS) and Yantai Institute of Coastal Zone Research. During his Ph.D., he and earned a China Scholarship Council award to work in the Ottemann Lab for part of his Ph.D. His postdoc focus is on H. pylori flagellar and chemotaxis signaling responses. When out of lab, he likes reading and hiking. Email:

Shuai Hu, Ph.D.

Postdoc Shuai grew up in Xi’an, China, the hometown of Terra-Cotta Warriors. He received his B.S. from Xiamen University, China, and M.S. from Indiana University Bloomington, and his Ph.D. in 2022 from the Microbiology and Environment Toxicology Department at UC Santa Cruz. His focus is on how host metabolites, such as lactate, bridge the connections between H. pylori and its host. During his leisure time, Shuai likes hiking, jogging, and hanging out with friends. Email:

Christina Yang, Ph.D student.

Christina grew up in the Central Valley before moving to Santa Cruz. She completed her B.S. in Molecular, Cell, and Developmental Biology at UCSC in 2016. As an undergraduate, she worked in the Ottemann lab studying H. pylori gland colonization dynamics. She started her graduate studies in 2016 in the Microbiology and Environmental Toxicology Dept. Her project investigates the relationship between chemotaxis and gland colonization dynamics with a focus on TlpB. Email:

Aaron Clarke, Ph.D. Student.

Aaron is from Duluth, Minnesota, where he received his B.S. in Biology from the Univ. of Minnesota Duluth. As an undergraduate, Aaron studied the role of natriuretic peptides on cochlear fluid balance and hearing loss under Dr. Trachte and Dr. Fitzakerley. He also studied tRNA fragments and their role as biomarkers in cancer while working with Dr. Lynne Bemis. After graduation, Aaron participated in PREP at the University of South Carolina and studied bacteriophage genomics under Dr. Bert Ely. Aaron joined the METX program in 2017 and is interested in antibiotic resistance. In his free time, Aaron likes to read, go to movies, and enjoy time in nature. Email:

Raymond Lopez Magaña, Ph.D. student.

Raymond was born in the central coast of California. He received his B.S. in Microbiology from SFSU where he studied host-microbe interactions in the J. Chen Lab. In 2017, he moved back to the central coast to start his graduate studies in the department of Microbiology and Environmental Toxicology at UC Santa Cruz. He is currently focused on understanding the role of a cytoplasmic chemoreceptor and its role in H. pylori pathogenesis. When not in lab, Raymond likes to hike, draw, and spend time with family. Email:

Yasmine Elshenawi, Ph.D. Student

Yazzy was born in Montreal but grew up in Orange County. She graduated in 2019 from UC Santa Cruz with a B.S. in Biology. She joined the Ottemann lab first as a postbac, then as a MS student in 2020, and now as a Ph.D. student in the Microbiology and Environmental Toxicology Dept. She is currently studying ribosomal silencing and chronic colonization in H. pylori. When she has free time she enjoys drawing, reading at the beach, and running. Email:

Angela Lane, Ph.D. Student

Angela was born in Arkansas, but she grew up in Oakland, California. She completed her BA at UC Berkeley in MCB, and then from 2018-2021, she completed her MS at SFSU where she studied cell communication via the Wnt signaling pathway at the Burrus lab. Angela joined the Ottemann Lab in Spring 2022, where she will study H. pylori transcriptional responses. During her leisure time, she participates in social justice work, watches Sci-fi movies, cooks low-fat gourmet dishes, and loves reading classical literature. Email:

Sydney Smyer, Ph.D. Student

Syd joined the lab in Spring of 2022, after completing her BS at University of San Diego. She is working to develop a project focused on the role of chemotaxis and how it affects pathogenesis, with a focus on the TlpC chemoreceptor.