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Host-Microbe Interactions
Role of Glycans During Infection
Using the Host Glycome to Modulate Health & Disease
Food Components Alter the Microbiome
Plant-Microbe Interactions
Weimer Group
Bart C. Weimer, Ph.D. bcweimer@ucdavis.edu
The infant gut undergoes a complex process of colonization during the first months of
life. Nursing infants consume milk oligosaccharides (MO) that play an important role in
establishing gut bacteria that modulate the immune system. MOs help protect the infant
from infections through reducing the ability of pathogens to bind gut cells. The MO
passes undigested to the distal gut where they are digested by prominent neonate gut
residents.
•Example project
Bacteroides induce mucus utilization genes to consume HMO
Probiotic interactions with unique cell populations in the gut
Induction of genes needed to digest the host molecules during infection
Salmonella is one of the most important foodborne pathogens in humans causing
gastroenteritis. WHO (2005) with USDA and CDC estimated that Salmonella infections
account for 1.4 to 1.6 million cases per year of foodborne illnesses in USA and
approach 1.5 billion cases world-wide. During infection ST must access the host cell
membrane before invasion occurs. ST overcomes the physical barriers of mucin and
the glycocalyx on the epithelial barrier to reach the underlying cell membrane where
they bind during infection. This team seeks to define the specific and host factors
involved in infection.
•Example projects
Glycan digestion during Salmonella infection
Probiotic/pathogen interactions
Prebiotic blocking to reduce animal shedding
Genomic differences between organisms for hypervirulent variatants
Food constituents are bioactive and often provide more that just nutrition. In some
cases individual components have anti-bacterial activity. These constituents are
thought to alter pathogen survival and persistence. For example, milk provides the
newborns with all the nutrients to grow and factors that promote health and fight
infection. Use of specific dietary components is now being used to alter the microbiome
and pathogen association to decrease disease and improve health in humans and
animals
•Example project
Lysozyme rich milk alters microbial populations
Milk fat to block pathogen association in the gut
Krill oil to modulate pathogen association on the skin and in the gut
Plant-microbe interactions provide important benefits for microbes and their host. One of
the main benefits is the supply of a primordial nutrient such as nitrogen to the plant.
Microbes will fix atmospheric nitrogen and renders it available to plants. Corn, a major
agricultural plant, requires intensive nitrogen fertilization. Our group studies a variety of
corn from Mexico that developed a mechanism of mucilage production from aerial roots
allowing the host to harbor a community of nitrogen fixers. The implication of this research
is huge considering the economical importance of nitrogen fertilization, especially in corn,
but also that new microbes and enzymes could be discovered as well as new mechanisms of
plant-microbe interactions.
•Example project
Functional N2-fixing microbiome of an indigenous landrace of maize
Microbial genome of novel bacterial isolates that influence plant performance
