Bacteriology

David A Baltrus

Associate Professor, Plant Sciences
Associate Professor, Animal and Comparative Biomedical Sciences
Associate Professor, BIO5 Institute
Member of the General Faculty
Member of the Graduate Faculty
Primary Department
Department Affiliations
Contact
(520) 626-8215

Work Summary

We are interested in understanding the genetic basis for bacterial interactions with other organisms (be they plants, insects, fungi, other bacteria), and on how evolution shapes these interactions. By better understanding the rules and molecules that structure such relationships, we hope to develop new ways to manipulate these interactions (e.g. through the development of specific antimicrobial compounds) or shape their evolutionary dynamics through time.

Research Interest

David Baltrus (PhD) is broadly interested in understanding how bacterial evolution is shaped by interactions with other organisms. Questions investigated by the Baltrus lab range from asking how evolutionary events such as the transfer of genes between microbes affects the development of antibiotic resistance to testing how microbiomes impact the development and physiology of plants and animals. The lab approaches these questions by using a variety of existing tools, from screening for mutants using "toothpicks and agar plates" to experimental evolution to comparative genomics. However, Dr. Baltrus is also highly interested in developing new tools that enable sequencing and tracking of bacterial populations and communities of interest (like potential pathogens) in real time under natural conditions.

Jean M Wilson

Professor, Cellular and Molecular Medicine
Director, Willed Body Program
Professor, Cancer Biology - GIDP
Professor, Neuroscience - GIDP
Professor, BIO5 Institute
Member of the General Faculty
Member of the Graduate Faculty
Primary Department
Contact
(520) 626-2557

Research Interest

Jean M. Wilson, Ph.D. is a Professor of Cellular and Molecular Medicine at the University of Arizona and member of the Arizona Cancer Center. Dr. Wilson’s work focuses on the establishment and maintenance of the mucosal barrier of the intestine. The cells of the intestine provide a selective barrier to pathogens and toxins, and loss of this barrier function is fundamental to pathologies such as inflammatory bowel disease and bacterial infection. In addition, loss of cellular interactions important for barrier function may predispose these cells to cancer. Work in Dr. Wilson’s laboratory focuses on a protein that is highly expressed in developing intestine, implying a critical role in the formation of the intestinal epithelium. Disruption of this protein compromises junctional integrity and epithelial polarity. Furthermore, expression of this protein is decreased in a model of neonatal necrotizing enterocolitis, a disease of newborns with high morbidity and mortality. These findings implicate this protein in the maintenance of intestinal barrier function in the neonate. In addition, continued expression in the adult intestine positions it to regulate epithelial permeability and polarity throughout life. Our studies focus on protein partners that interact with this protein with the goal of identifying the molecular machinery that regulates this pathway.

VK Viswanathan

Professor, Animal and Comparative Biomedical Sciences
Co-Director, Collaboratory for Anti-infectives and Therapeutics
Professor, BIO5 Institute
Member of the General Faculty
Member of the Graduate Faculty
Contact
(520) 626-7687

Work Summary

Around the world, diarrhea kills ninety children every hour. My laboratory uses the latest technology to understand how bacteria cause diarrhea in children. In addition to providing clues for new ways to prevent disease, our research helps us understand how the body maintains good health.

Research Interest

Dr. Viswanathan’s research efforts over the past 12 years have focused on the mechanisms of pathogenesis of the diarrheal disease pathogens enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC). His laboratory characterized EPEC and EHEC virulence factors (specifically those secreted into host cells) and evaluates their effect on host cell physiology including barrier function, cell death pathways, and effects on innate immune responses. His specialization is innate immune signaling by intestinal epithelial cells in vitro and in vivo, and includes the use of cutting-edge technologies such as in vivo phosphoproteomics, and single-cell manipulation during bacterial infection. He also offers a very popular upper-division course in pathogenic bacteriology, and actively mentors undergraduate and graduate students, and post-doctoral fellows at the UA. Keywords: Pathogenic E. coli, Clostridium difficile, infection, host-pathogen interactions

Jana M U'Ren

Assistant Professor, Ecosystem Genomics
Assistant Professor, Agricultural-Biosystems Engineering
Assistant Professor, Animal and Comparative Biomedical Sciences
Assistant Professor, Genetics - GIDP
Assistant Professor, BIO5 Institute
Member of the Graduate Faculty
Primary Department
Department Affiliations
Contact
(520) 621-1607

Work Summary

We study the biodiversity, biogeography, evolutionary origins, and ecological roles of plant-associated microorganisms. We use a combination of traditional culture-based microbiology, functional assays, and next-generation 'omics tools to study microbial symbiont communities in diverse lineages of land plants at scales ranging from local to global. We are interested in characterizing the biotic and abiotic factors shaping the assembly of plant-associated fungal communities, how community structure and diversity impacts ecosystem function, and the evolutionary dynamics of fungal symbiont evolution in the context of closely related pathogens and saprotrophs.

Research Interest

I am an integrative microbial ecologist with training in microbial ecology, evolutionary biology, mycology, and genomics. I am an Assistant Professor of Ecosystem Genomics in the Department of Agricultural and Biosystems Engineering and the BIO5 Institute. I completed a BA in Biological Sciences from the University of Missouri-Columbia and my PhD in Plant Pathology from University of Arizona’s School of Plant Sciences. Keywords: plant-microbe interactions, comparative genomics, microbial ecology, fungal endophytes

Magdalene Yh So

Professor, Immunobiology
Director, Microbial Pathogenesis Program
Professor, Animal and Comparative Biomedical Sciences
Professor, Biochemistry/Molecular Biophysics
Professor, Genetics - GIDP
Professor, Molecular and Cellular Biology
Professor, BIO5 Institute
Primary Department
Department Affiliations
Contact
(520) 626-3097

Work Summary

How do bacteria "talk" to the body? How does the body reply to the microbe? How does this conversation affect your health and well being?

Research Interest

Magdalene So, PhD, is a Professor in the Immunobiology Department and Director of the Microbial Pathogenesis Program at the University of Arizona College of Medicine. Dr. So is recognized internationally for her research in the microbial pathogenesis. Her research focuses on two medically important bacterial pathogens: Neisseria gonorrhoeae, which causes over 100 million new cases of sexually transmitted infections each year worldwide, and Neisseria meiningitidis, which frequently causes meningitis epidemics in Subharan Africa. Her goal is to understand on how these two pathogens cause disease, with the aim of applying this information to developing new antibiotics for treating these infectious agents and improving current methods of vaccine development. Dr. So recently expanded her research to the commensal species in the Neisseria genus. These bacteria are normal inhabitants of the body and are closely related to the two pathogenic species; but unlike their pathogenic cousins they do not cause disease. Dr. So’s new research effort seeks to determine the differences in behavior of commensal and pathogen Neisseria. Dr. So’s research approach is multidisciplinary, involving concepts and techniques in biophysics, bioinformatics, cell biology, biochemistry and genetics. Collaborators from institutions around the world contribute to this effort. Dr. So has published over 100 peer-reviewed research papers in internationally renowned journals, and over 20 reviews and book chapters. She holds several patents as a result of her research. She is frequently invited to speak at universities and national and international meetings. She is a member of the American Academy of Microbiology, an elected body, and serves on the scientific boards of several research centers. Over the course of her career, Dr. So has trained over 44 postdoctoral fellows and graduate students. The majority of her trainees are internationally recognized researchers in their own right. Keywords: Infectious disease, microbiology

Sadhana Ravishankar

Associate Professor, Animal and Comparative Biomedical Sciences
Associate Professor, Applied BioSciences - GIDP
Member of the Graduate Faculty
Associate Professor, BIO5 Institute
Department Affiliations
Contact
(520) 626-1499

Research Interest

Sadhana Ravishankar, PhD, focuses on the stress response in foodborne pathogenic bacteria, including methods of pathogen control and natural antimicrobials. In the lab, Dr. Ravishankar attempts to control foodborne pathogenic bacteria including antibiotic resistant strains using various technologies and multiple hurdle approaches. Natural antimicrobials and their applications in various foods, antimicrobial and anti-oxidative activities of plant compounds also interest her. Bacterial attachment, biofilm formation and their control along with stress tolerance responses of foodborne pathogenic bacteria, and mechanisms of stress response in bacteria are some other subjects of research for Dr. Ravishankar’s lab.

Michael D L Johnson

Associate Professor, Applied BioSciences - GIDP
Associate Professor, BIO5 Institute
Associate Professor, Immunobiology
Member of the Graduate Faculty
Primary Department
Department Affiliations
Contact
(520) 626-3779

Work Summary

Metals such as calcium and iron are essential to living organisms. Some metals in excess, like copper, are detrimental to bacteria. My laboratory studies this phenomenon in Streptococcus pneumoniae to find novels method for killing pathogenic bacteria.

Research Interest

Metals serve as vital nutrients to all biological systems. During infections, bacteria must not only acquire all metals necessary for survival from within the host, such as calcium or manganese, but must also efflux metals that are toxic or in excess such as copper. The overall goal of my laboratory is to investigate how bacteria maintain homeostasis within the metal milieu. This goal involves determining how metals are processed, the orchestrated response during metal sensing, and the role that the host plays in this process during infection. Understanding how bacteria interact with metals during infections will identify novel therapeutic strategies against bacterial infections. Keywords: Infectious Diseases, Antibiotic resistance, Bacterial Pneumonia

Melissa Herbst-Kralovetz

Professor, Basic Medical Sciences
Associate Professor, Clinical Translational Sciences
Associate Professor, Obstetrics and Gynecology
Associate Professor, BIO5 Institute
Contact
(602) 827-2247

Research Interest

Melissa Herbst-Kralovetz, PhD is an Associate Professor in the Departments of Basic Medical Sciences and Obstetrics and Gynecology and is Director of the Women's Health Microbiome Initiative at the UA College of Medicine-Phoenix. The Herbst-Kralovetz research lab is broadly interested in understanding innate mucosal immune responses to resident bacteria, pathogens (e.g HSV-2), and microbial products at mucosal sites, including the female reproductive tract. The mucosa provides a major immune barrier (physical, biological, and chemical) to microbial insult and her lab is interested in studying the mucosal barrier function of the lower female reproductive tract and its role in host defense against infection and inflammation as well as maintaining mucosal homeostasis. Dr. Herbst-Kralovetz has a long-standing interest and background in studying infections/conditions that impact women’s health.

Frank Anthony Duca

Assistant Professor, Gastrointestinal Microbiology
Assistant Professor, Physiological Sciences - GIDP
Assistant Professor, BIO5 Institute
Department Affiliations
Contact
(520) 621-9544

Research Interest

An overwhelming obesogenic environment, the backdrop to a globally-expanding western lifestyle, has led to a ‘diabesity’ pandemic that represents a costly and urgent global health crisis. The success of gastric bypass surgery and gut-derived diabetes/obesity treatments highlight the major role of the gastrointestinal (GI) tract in metabolic diseases. My research aims to better understand the complex intestinal signaling mechanisms involved in the regulation of energy and glucose homeostasis in physiological and pathophysiological states. My work to date has focused on elucidating how nutrients are sensed by the gut, and how changes in these mechanisms lead to a reduction in food intake and/or a reduction in endogenous hepatic glucose production via a gut-brain neuronal axis. More specifically, my work focused on alterations in intestinal detection of fats and carbohydrates and paracrine gut peptide signaling (CCK and GLP-1) during high-fat feeding, the influence of the gut microbiota on these pathways, and how these contribute to the development of obesity and diabetes. As such, I plan to continue to decipher this complex interaction between gut-sensing mechanisms and the gut microbiota, as a better understanding of these pathways are crucial for the development of successful, gut-targeted therapeutic options in the treatment of metabolic diseases. Given the rapid rise of obesity/diabetes in only several generations, obesity cannot be attributed to genomic alterations, but more likely results from a complex set of interactions between genetic risk factors and environmental changes. Importantly, studies suggest the development of adult phenotypes (obesity and diabetes) results from early, transient environmental interactions, coined ‘early life programming,’ which has been partly attributed to epigenetic changes. Gut microbiota development is also crucial during this time, and differing modes of development (i.e. maternal microbiota, type of delivery, breastfeeding vs. formula feeding, etc.) can lead to later metabolic dysfunctions. Therefore, using animals models prone to the development of obesity and/or diabetes from polygenetic inheritance and transgenerational, epigenetic, changes in gene activity, I am studying how varying environmental factors (diet, housing, exercise, pre/post-natal environment, etc.) result in differential effects on the gut microbiota, intestinal nutrient sensing, and whole body energy and glucose homeostasis. A better understanding of how early changes in the gut microbiota can impact the development of metabolic regulation, and vice versa, is vital for developing successful strategies to curb diabetes and obesity.

Judith K Brown

Professor, Plant Science
Regents Professor, Plant Sciences
Research Associate Professor, Entomology
Professor, Entomology / Insect Science - GIDP
Professor, BIO5 Institute
Member of the General Faculty
Member of the Graduate Faculty
Primary Department
Department Affiliations
Contact
(520) 621-1402

Work Summary

Unravel the phylodynamics and transmission-specific determinants of emerging plant virus/fastidious bacteria-insect vector complexes, and translate new knowledge to abate pathogen spread in food systems.

Research Interest

Judith Brown, PhD, and her research interests include the molecular epidemiology of whitefly-transmitted geminiviruses (Begomoviruses, Family: Geminiviridae), the basis for virus-vector specificity and the transmission pathway, and the biotic and genetic variation between populations of the whitefly vector, B. tabaci, that influence the molecular epidemiology and evolution of begomoviruses. Keywords: Plant viral genomics, emergent virus phylodynamics, functional genomics of insect-pathogen interactions