Departmental News and Events
Why do some foodborne bacteria make us sick? A paper published Sept. 16 in the journal Science has found that pathogens in the intestinal tract cause harm because they benefit from immune system responses designed to repair the very damage to the intestinal lining caused by the bacteria in the first place.
”The finding is important because it explains how some enteric pathogens can manipulate mammalian cells to get the oxygen they need to breathe,” said Andreas Bäumler, a professor of medical microbiology and immunology at UC Davis School of Medicine and lead author of the study. “It also offers new insight into developing strategies targeting the metabolism of the intestinal lining to prevent the expansion of harmful bacteria in the gut, a situation that is exacerbated by the overuse of antibiotics.”
A healthy large intestine is mostly free of oxygen, and the beneficial microbes residing there thrive in this anaerobic environment. In contrast, enteric pathogens, such as Escherichia coli in humans or Citrobacter rodentium in mice, need oxygen to survive.
Bäumler’s team discovered how these pathogens change the gut environment to favor their own growth.
“Enteric pathogens deploy virulence factors that damage the intestinal lining and cause diarrhea,” Bäumler said. “To repair the damage, the body accelerates the division of epithelial cells that form the intestinal lining, which brings immature cells to the mucosal surface. These new cells contain more oxygen and wind up increasing oxygen levels in the large bowel, creating an environment that allows gut pathogens like E. coli to outcompete the anaerobic-loving resident microbes.”
Bäumler’s research has important implications for developing new treatment strategies that target factors that compromise the intestinal-lining function or bolster microbiota composition to offer either resistance or assistance to invading pathogens.
“The rise of antibiotic-resistant strains of bacteria has become a major public health threat worldwide, Bäumler said. “As more bacterial strains do not respond to the drugs designed to kill them, the advances made in treating infectious diseases over the last 50 years are in jeopardy.”
This year, the Centers for Disease Control and Prevention identified three drug-resistant organisms – Clostridium difficile, Carbapenem enterobacteriaceae and Neisseria gonorrhoeae – as requiring urgent attention, and in May, a report commissioned by the UK government predicted that by 2050 antimicrobial-resistant infections could claim 10 million lives a year and cost up to $100 trillion from the global economy.
Understanding how gut pathogens manipulate the body’s natural defense mechanisms to grab hold and contribute to abnormal states within and beyond the GI tract is a burgeoning area of research at UC Davis. Scientists from schools and colleges across the campus are investigating antibiotic resistance as well as the influence that gut-flora imbalances have on many conditions, including brain health and behavior, obesity, inflammatory bowel disease, irritable bowel syndrome, GI cancers, cardiovascular disease, fatty liver disease, autism, arthritis and asthma.
UC Davis study details how treatment with antibiotics increases availability of oxidized sugars to generate nutrients that benefit the growth of bacterial pathogens.
(SACRAMENTO, Calif.) -- The research on antibiotics has traditionally focused on the mechanisms by which they contribute to controlling the growth of bacteria as well as on the development of new drugs. But it has also been known that, paradoxically, some bacterial pathogens can benefit from the consequences of antibiotic treatment in causing disease. However, the mechanisms behind this relation remain elusive.
Antibiotics are essential for fighting bacterial infection, but paradoxically, in some instances they can make us more prone to developing diarrhea. That is because antibiotics don’t just kill “bad” bacteria; they can also kill the “good” ones normally residing in our gut to protect us from pathogens. However, the mechanisms by which our resident gut microbes confer protection against pathogens, such as Salmonella, remain poorly understood. In a paper published April XX, 2016, researchers from UC Davis and UT Southwestern figured out why.
Our body absorbs nutrients in the small intestine, but our digestive tract cannot break down natural fibers from vegetables. Thus fibers pass through into the large intestine, which is teaming with beneficial microbes that are specialized on breaking down this plant material into a short organic acid, termed butyrate. To generate energy for water absorption, our cells lining the large intestine then use oxygen to burn microbe-derived butyrate; that’s how we consume fiber. A team led by Dr. Baumler found that when mice were given antibiotics, the beneficial microbes were depleted along with butyrate, thus preventing the cells lining the large intestine to consume oxygen, which dramatically increased oxygen availability in the gut lumen. Unlike our beneficial microbes, which specialize on growing in the complete absence of oxygen, Salmonella was able to benefit from the resulting increase in oxygen availability, which drove a bloom of the pathogen in the gut after antibiotic treatment. Thus by preventing beneficial microbes from providing nutrition for the cells lining our large intestine, antibiotic treatment can make us more susceptible to Salmonella infection. This finding will help to devise strategies to prevent this unwanted side effect of antibiotic treatment.
For outstanding teaching and mentoring, molecular biologist Shirley Luckhart has been named the recipient of the 2016 “Award for Excellence in Service to Graduate Students,” sponsored by the UC Davis Graduate Student Association.
“This is a wonderful surprise,” said Luckhart, professor with the Department of Medical Microbiology and Immunology and adjunct professor in the Department of Entomology and Nematology.
She will receive the award on April 8 at the annual Interdisciplinary Graduate and Professional Student Award Banquet.
Luckhart, whose expertise includes molecular cell biology and biochemistry of malaria parasite transmission, was singled out for creating a thriving lab environment and her drive to help her students succeed.
Researchers at UC Davis have discovered an unexpected link between how the immune system sounds an alarm when its cells are taken over by pathogens during an infection and how an inflammatory response is triggered.
The finding of this novel link, published in the journal Nature on March 23, is important because it helps researchers understand how a cell senses bacterial or viral infection, and how these pathways are linked to inflammatory diseases, such as inflammatory bowel disease, diabetes and atherosclerosis.
Highly active anti-retroviral therapy (HAART) has helped millions survive the human immunodeficiency virus (HIV). Unfortunately, HIV has a built-in survival mechanism, creating reservoirs of latent, inactive virus that are invisible to both HAART and the immune system.
Read more here: AAAS, United Press International wire service (UPI), Medical News Today, BBC News, The Week (UK), Daily Mail (UK), Futurity, SacBee Article
The study was published in PLoS Pathogens Journal
Some doctoral students at the University of California, Davis, are going far beyond campus labs and academia. They are engaging in practical work at a leading pharmaceutical company, studying air pollution for a state agency and researching malaria in Uganda.
Surprising discovery: HIV hides in gut, evading eradication
Researchers at UC Davis have made some surprising discoveries about the body's initial responses to HIV infection. Studying simian immunodeficiency virus (SIV), the team found that specialized cells in the intestine called Paneth cells are early responders to viral invasion and are the source of gut inflammation by producing a cytokine called interleukin-1 beta (IL-1β).
Though aimed at the presence of virus, IL-1β causes breakdown of the gut epithelium that provides a barrier to protect the body against pathogens. Importantly, this occurs prior to the wide spread viral infection and immune cell killing. But in an interesting twist, a beneficial bacterium, Lactobacillus plantarum, helps mitigate the virus-induced inflammatory response and protects gut epithelial barrier. The study was published in the journal PLoS Pathogens.
One of the biggest obstacles to complete viral eradication and immune recovery is the stable HIV reservoir in the gut. There is very little information about the early viral invasion and the establishment of the gut reservoir.
"We want to understand what enables the virus to invade the gut, cause inflammation and kill the immune cells," said Satya Dandekar, lead author of the study and chair of the Department of Medical Microbiology and Immunology at UC Davis.
"Our study has identified Paneth cells as initial virus sensors in the gut that may induce early gut inflammation, cause tissue damage and help spread the viral infection. Our findings provide potential targets and new biomarkers for intervening or blocking early spread of viral infection," she said.
Breast vs. bottle feeding in rhesus monkeys Infants receiving different diets after birth develop distinct immune systems
Infant rhesus monkeys receiving different diets early in life develop distinct immune systems that persist months after weaning, a study by researchers from UC Davis, the California National Primate Research Center (CNPRC) at UC Davis and UC San Francisco has shown. The study, which compares breast- and bottle-fed infants, appears online September 3 in Science Translational Medicine.
Read more here, Published in Science Translational Medicine
U.S. News' ranks UC Davis Medical Center programs among the nation's best
UC Davis Medical Center has ranked as one of the nation’s best hospitals for 2014-15 in 10 adult medical specialties by U.S. News & World Report. The annual U.S. News Best Hospitals rankings, released July 15, recognize hospitals that excel in treating patients with the most serious and challenging injuries and illnesses.
“The results of the U.S. News & World Report survey reflect the excellence and compassion of everyone here who cares for our patients,” said Ann Madden Rice, chief executive officer, UC Davis Medical Center.
Read more here, News from UC Davis Health System
New Insights into how genes turn on and off
Dr. Janine LaSalle, Professor in the Department of Medical Microbiology and Immunology, in conjunction with researchers at the University of British Columbia, have shed new light on methylation, a critical process that helps control how genes are expressed. Her paper, titled "The human placenta methylome" was published online this week in the Proceedings of the National Academy of Sciences (PNAS).
In addition to enhancing our understanding of epigenetics, this work could influence cancer research and help illuminate how environmental toxins affect fetal development.
Researchers discover molecular target for the bacterial infection brucellosis
Dr Renee Tsolis’ research group has uncovered a potential drug target for the development of an effective therapy against the debilitating, chronic form of the bacterial disease brucellosis, which primarily afflicts people in Mediterranean and Middle Eastern countries.
UC Davis researchers discover molecular target for the bacterial infection brucellosis
Paul Ashwood co-author on 2 autism related papers
Dr. Paul Ashwood, a professor in Med Micro and a researcher in the MIND institute, is co-author on two papers published in July:
Identification of specific fetal antigens attacked by maternal antibodies
Findings of how exposure to prenatal maternal antibodies affects behavior, development in offspring
UC Davis researchers discover how cells distinguish friend from foe
Dr Andreas Baumler, Professor in the department of Medical Microbiology and Immunology at UC Davis, and his team have shown how the innate immune system distinguishes between dangerous pathogens and friendly microbes. Like burglars entering a house, hostile bacteria give themselves away by breaking into cells. However, sensing proteins instantly detect the invasion, triggering an alarm that mobilizes the innate immune response. This new understanding of immunity could ultimately help researchers find new targets to treat inflammatory disorders. The paper, titled "Manipulation of small Rho GTPases is a pathogen-induced process detected by NOD1" was published in Nature on March 31.
Dr Andreas Baumler finds key to growth of "bad" bacteria in inflammatory bowel disease
Scientists have long puzzled over why “bad” bacteria such as E. coli can thrive in the guts of those with inflammatory bowel disease (IBD), causing serious diarrhea. Now UC Davis researchers have discovered the answer—one that may be the first step toward finding new and better treatments for IBD.
Scientists find key to growth of "bad" bacteria in IBD
Dr. Thompson given IDSA award
The Infectious Diseases Society of America (IDSA) has awarded Angie Gelli PhD of the Department of Pharmacology, and George R. Thompson MD a faculty member in the Department of Medical Microbiology and Immunology, the 2012 Program committee Choice Award for their work on invasion of the central nervous system by Cryptococcus spp.
Their work was highlighted at an awards presentation on the opening night of the conference held in San Diego, CA during which only 4 presentations were honored for outstanding scientific research.
Together, Dr.'s Gelli and Thompson were able to determine the role of a secreted metalloprotease that is required for invasion into the central nervous system and hope to further characterize both the activity and expression of this enzyme in a human cohort in future studies.
BRCMS awards Aicha Toure for best poster presentation
The Annual Biomedical Research Conference for Minority Students has awarded Aicha Toure best poster presentations in the discipline of Immunology for her poster titled: “Increased Proliferation of Intestinal Epithelial Cells In Early SIV Infection.” Aicha is a senior undergraduate student who is majoring in Biological Sciences with an emphasis in Medical Microbiology. During the 2012-13 academic year she is participating in an undergraduate research internship in the lab of Dr. Satya Dandekar in the Department of Medical Microbiology & Immunology, and is investigating changes in intestinal epithelial integrity during SIV infection.
Cases of Valley fever on the rise
Dr. George Thompson, assistant professor and assistant director of the coccidioidomycosis serology laboratory, comments on the rising number of cases of Valley Fever seen throughout the central valley.
Valley Fever cases, costs mount
UC Davis-led conference promotes new collaborations in Brazil
An interdisciplinary delegation of researchers and educators, led by UC Davis, met this month at the Integrated Biological Networks Driving Disease Outcomes conference in Uberlândia, Brazil, to explore new opportunities for collaboration with the Brazilian Research Network in the biomedical and translational sciences.
Co-chairs of the conference were Satya Dandekar, professor and chair of medical microbiology and immunology at UC Davis School of Medicine, and Luiz Goulart, a professor at UFU's Institute of Genetics and Biochemistry and visiting professor in UC Davis' medical microbiology and immunology department.
See the rest of the story here.
MMI Department Chair Receives RISE Award
Satya Dandekar, Professor and Chair of Medical Microbiology and Immunology, has been awarded funding from the new Research Investments in Sciences and Engineering (RISE) program to conduct innovative, multidisciplinary research in areas of strategic importance to California, the nation and the world.
Established by the UC Davis Office of Research earlier this year, the program has awarded a total of $10 million to support 12 research projects over the next three years. Five projects are led by UC Davis Health System faculty. See the story here.
Med Micro researcher receives grant from American Heart Association
Dr. Arina Marijke Keestra, an Assistant Project Scientist in Andreas Baumler’s laboratory, received a prestigious National Scientist Development Grant from the American Heart Association, a four-year award totaling $ 308,000. The National Scientist Development Grant from the American Heart Association supports highly promising beginning scientists in their progress toward independence by encouraging and adequately funding research projects that can bridge the gap between completion of research training and readiness for successful competition as an independent investigator. The long-range goal of Dr. Keestra’s research supported by the National Scientist Development Grant is to elucidate pathways of innate immunity that can distinguish harmless microbes from pathogens, thereby enabling the host to mount responses that are commensurate with the threat.
UC Davis dermatologist among scientists honored with Presidential award
Emanual Maverakis, assistant professor of dermatology at UC Davis School of Medicine, joins a highly select group later this month in a White House ceremony honoring recipients of this year's Presidential Early Career Awards for Scientists and Engineers, the highest honor bestowed by the United States government on outstanding scientists and engineers in the early stages of their independent research careers.
Immune System weaves cobweb-like nanonets to snag intestinal microbes
A team of researchers led by Dr. Charles Bevins has found that human alpha-defensin 6 (HD6) -- a key component of the body's innate defense system -- binds to microbial surfaces and forms "nanonets" that surround, entangle and disable microbes, preventing bacteria from attaching to or invading intestinal cells.
UC Davis Microbiologist leads study to identify HIV vaccine target
Dennis Hartigan-O'Connor, a new assistant professor in the UC Davis Department of Medical Microbiology, is the principal investigator of a study that has identified a potential new target for developing therapies or vaccines for HIV.
Shirley Luckhart receives outstanding mentor award
Congratulations to UC Davis molecular biologist Shirley Luckhart, professor of Medical Microbiology and Immunology (MMI) and a graduate student advisor with the UC Davis Department of Entomology! She’s just received a 2012 Outstanding Mentor Award from the UC Davis Consortium for Women and Research. Luckhart, an international authority on malaria, was nominated through a joint effort of her 15-member lab, and supported by former students, postdocs and faculty colleagues. Writing letters of support were doctoral candidates Anna Drexler and Elizabeth Glennon; postdoctoral scholar Nazzy Pakpour; and MMI associate professor Maria Mudryj. Read what her lab members said about her here.
UC Davis MIND Institute researchers present on autism at AAAS Annual Meeting in Vancouver
Janine LaSalle, professor in the Department of Medical Microbiology and Immunology and Isaac Pessah, Director of the UC Davis Children's Center for Environmental Health and Disease Prevention led a symposium on relationships between genetic, epigenetic and environmental influences on the development of autism in children during the American Association for the Advancement of Science (AAAS) Annual Meeting, Feb. 16 -18 in Vancouver, Canada.
The research findings of Dr. LaSalle indicate that exposure to even low levels of flame retardants may affect the brain of a developing fetus and possibly contribute to autism. This story was also covered by MyHealthNewsDaily.com and IrishTimes.com.
Genetics and Man Made Chemicals Equally to Blame
Dr. Eisen elected as a fellow in American Academy of Microbiology
Jonathan A. Eisen, professor of medical microbiology and immunology at UC Davis Health System, has been elected as a fellow in the American Academy of Microbiology, the honorific leadership group of the American Society for Microbiology, which is the world's oldest and largest life-science organization.
UC Davis Professor Named American Academy of Microbiology Fellow
Barbara Shacklett's research highlighted in Science Daily
Dr. Shacklett’s paper titled "Myeloid dendritic cells isolated from tissues of SIV-infected Rhesus macaques promote the induction of regulatory T cells" is higlighted in the February 14th edition of Science Daily. The paper was published in the January 28, 2012 issue of AIDS.
SIV Infection May Lead to Increase in Immune-Suppressive Treg Cells
Research led by Paul Ashwood has been honored by Autism Speaks as one of the top 10 Research Achievements of 2011.
Dr. Ashwood’s paper titled "Elevated plasma cytokines in autism spectrum disorders provide evidence of immune dysfunction and are associated with impaired behavioral outcome" found significantly altered adaptive cellular immune function in children with autism spectrum disorders that may reflect dysfunctional immune activation, and that these alterations may be linked to disturbances in behavior and developmental functioning. It was published in January 2011 in the journal Brain, Behavior and Immunity. A link to Dr. Ashwood's paper can be found here.
UC Davis MIND Institute autism studies among the world's best in 2011
Dr. Thompson and Dr. Pappagianis paper cited as Top Ten Paper
Dr. George Thompson and Dr. Demosthenes Pappagianis were coauthors on a paper recently cited as one of the top 10 papers in clinical mycology at the 51st Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) attended by over 10,000 medical professionals. Their paper describes abrogation of an IgG response in patients treated very early for coccidioidal infection, and defines the mechanism as the indirect suppression of the IgG antigen CTS1 with fluconazole administration. Their report was the first observation of this phenomenon in mycology. A link to the paper can be found here.
Med Micro Signs Agreement with Universidade Federal de Uberlandia, Brazil
An Agreement of Cooperation between the UC Davis Department of Medical Microbiology & Immunology and the Universidade Federal de Uberlandia (UFU), Brazil has been approved by both institutions. The Agreement will promote scientific scholarly activities, research collaborations and international understanding through the exchange of visiting scholars at both institutions. Dr Luiz Goulart, a Visiting Professor from UFU has been based in Med Micro since 2009. It was through his efforts that this agreement was established. Dr Goulart commented “I am very pleased that I have been able to be a part of the process in deepening the relationship between both institutions.”
Dr. Pomeroy elected to Institute of Medicine
Congratulations to Dr. Claire Pomeroy who has been elected to the Institute of Medicine, one of the nation’s highest honors in health and medicine.
Dr. Pomeroy elected to Institute of Medicine
Dr. Pomeroy comments on role of social factors in U.S. health care
In this opinion piece, Dr. Pomeroy, Vice Chancellor for Human Health Sciences, Dean of the School of Medicine, and Medical Microbiology & Immunology faculty member, comments on the critical need to address the social determinants of health as part of health-care reform.
Social factors play huge role in U.S. health.
Dr. Maverakis receives NIH Director's New Innovator Award
Dr. Emanuel Maverakis has received the NIH Director’s New Innovator Award. The NIH Director's Award programs are designed to reinvigorate and advance science and medicine by enabling investigators to pursue entirely new directions in research, with an emphasis on risk taking and innovation.
Three UC Davis Researchers Win Prestigious NIH Awards
New genetically engineered vaccines target Rift Valley Fever
Tilahun Yilma, a Med Micro faculty, is lead author reporting the development of two genetically engineered vaccines to combat the mosquito-borne Rift Valley fever, devastating to livestock and so far confined to Africa and the Middle East.
Chuck Bevins paper featured in New York Times Story
Dr. Chuck Bevins recent paper linking Male infertility to a missing protein was featured in a story in The New York Times. The paper was published in the July 20, 2011 edition of Science Translational Medicine.
Study Links Male Infertility to a Missing Protein
Jonathan Eisen's PLoS ONE paper featured in The Economist
Dr. Jonathan Eisen's recent article in PLoS ONE is featured in the March 24th edition of The Economist. The paper discusses Dr. Eisen's pursuit of expanding our understanding of the diversity of life.
A New Domain of Life
Claire Pomeroy to be honored as Safety Net Hero
Dr. Claire Pomeroy, Chief Executive Officer of UC Davis Health System, UC Davis Vice Chancellor for Human Health Services and Dean of the School of Medicine, will be honored as a “Safety Net Hero” at the upcoming Spring Break 2011 fundraiser.
Claire Pomeroy to be honored as Safety Net Hero
Researchers within Med Micro working to find a cure for HIV
In a letter from UC Davis Health System CEO and UC Davis Medical School Dean Claire Pomeroy, Medical Microbiology faculty members Satya Dandekar, Barbara Shacklett and Richard Pollard are highlighted for their efforts in finding a cure for the HIV virus.
Working tirelessly to find a cure for HIV
Med Micro places 12th out of 96 Microbiology departments for NIH funding in 2010
The UC Davis School of Medicine rose to 37th place among 134 schools of medicine in the United States in an annual ranking based on the amount of National Institutes of Health (NIH) research funds received over the course of a year. UC Davis School of Medicine ranked particularly high in basic sciences, including microbiology (12th out of 96 surveyed).
UCD School of Medicine among top 40 for NIH funding
Paul Ashwood paper highlighted by NIEHS
Dr. Paul Ashwood’s research into children with autism spectrum disorders is featured in the National Institute of Environmental Health Sciences (NIEHS) Newsletter (March 2011).
Elevated plasma cytokines in children with autism spectrum disorder
Renee Tsolis Appointed to NIH study Section
Renee Tsolis has been appointed to Vaccines Against Microbial Diseases Study Section, Center for Scientific Review, NIH, effective July 1, 2011-June 30, 2015. Dr Tsolis was nominated because of her demonstrated competence and achievements as evidenced by the quality of her research accomplishments, publications and other significant scientific activities, achievements and honors.
Claire Pomeroy named 2011 Businesswoman of the Year
Sacramento Metro Chamber announced that Claire Pomeroy, Faculty member of MMI, Dean of the UC Davis Medical School and CEO of the UC Davis Health System, is its "2011 Businesswoman of the Year." The chamber recognized her for helping make UC Davis "a major contributor to the health care industry and economy of the Sacramento region."
Shirley Luckhart's contribution recognized in Time Magazine
Time magazine selected the "malaria-proof mosquito," developed with the contributions of professor Shirley Luckhart as one of its 50 Best Inventions of 2010.
The 50 Best Inventions of 2010
Andreas Baumler recognized with top biology paper of 2010
The Scientist selected a study co-written by Andreas Baumler, professor and vice chair of research for the department, as the top paper in biology in 2010.
The Top 5 Papers of 2010
Barbara Shacklett discusses her work with HIV controllers
Barbara Shacklett discusses her work with HIV controllers and announces the launch of three new clinical studies on women (controllers) in the Bay Area of Northern California.
Paul Ashwood featured in Autism Speaks
Research from Dr. Paul Ashwood was featured in this year's newsletter from Autism Speaks.
New research identifies environmental risk factors for autism
Andreas Baumler to serve on NIH study section
Dr. Andreas Baumler has been appointed to serve on the NIH Host Interactions with Bacterial pathogens Study Sections, Center for Scientific Review for the period July 1, 2010 to June 30, 2014. Members are selected for this Study Section on the basis of their demonstrated competence and achievement in their scientific discipline as evidenced by the quality of research accomplishments, publications in scientific journals, and other significant scientific activities, achievements and honors.
Kathy DeReimer to receive NIH New Innovator Funding
Congratulations to Kathy DeRiemer for being awarded a 5 year NIH grant to support her research on Tuberculosis.
UC Davis Investigators to receive NIH New Innovator Funding
Barbara Shacklett appointed to AIP and ANRS study sections
Barbara Shacklett has been appointed to two Study Sections: National Institutes of Health: AIDS Immunology and Pathogenesis ("AIP") Study section (2009-2013; and The French National AIDS Research Agency, ANRS: Study Section CSS1, Host-Virus Interactions (2009-2012).