Bacteria

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, 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.

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

Dr. Vedantam’s research interests are broadly focused on pathogenic mechanisms leading to antibiotic-associated diarrhea, and include host-pathogen studies of the diarrheagenic agent Clostridium difficile. C. difficile infection is currently a leading healthcare-acquired disease in the USA, incurring over $3 billion in treatment and containment costs. Dr. Vedantam’s laboratory uses multiple genomic and proteomic approaches to study C. difficile pathogenesis, including, but not limited to, automated iTRAQ-based comparative proteomics, and genomic analyses. Her laboratory also offers hospital surveillance and typing services, and a genetic manipulation program for clostridial pathogens. These efforts have identified attractive targets for interventions aimed at eliminating C. difficile from the gut, and are a focus of translational research goals. Dr. Vedantam is also involved in multiple teaching efforts, and offers a highly popular, upper-division, laboratory-based course on bacterial pathogens. The strengths she brings to any research endeavor are based on her expertise in genetic, mechanistic and animal model studies. Keywords: Infectious Disease, healthcare-associated infections, bacterial pathogenesis

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 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, 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.

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

Martha Hunter, PhD, conducts research largely focused on understanding the evolutionary biology and ecology of parasitoids and predators important in biological control of agricultural pests. A group that has been central to much of her research are members of the aphelinid genus Encarsia, parasitoids of whiteflies and scale insects. Recently, the theme of her research has turned to the role of symbiotic microorganisms on the ecology and evolution of natural enemies. Dr. Hunter has found a bacterial symbiont in the Bacteroidetes, recently named Cardinium hertigii, that is unrelated to the better known proteobacterium, Wolbachia, but also manipulates the reproduction of is hosts in ways that enhances its transmission. Like Wolbachia, it induces parthenogenesis as well as cytoplasmic incompatibility in the autoparasitoid genus Encarsia, two reproductive phenotypes thought to be unique to Wolbachia.

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.