Benson Lab Home Page

David R. Benson Professor of Microbiology, PhD, FAAM, Department of Molecular & Cell Biology U-3125 University of Connecticut Storrs, CT 06269-3125 Phone: 860-486-4258 e-mail: david.benson@uconn.edu

Over the years, my research has focused on various aspects of microbiology. Most recently, students have studied four topics: the actinorhizal symbiosis, cheese microbiology, tick symbionts and the biochemistry of psychrophilic bacteria. The unifying theme behind these areas is the interaction of microorganisms with their environment, whether it be in plants, in animals, in food or at temperature extremes.

The Actinorhizal Symbiosis

The actinorhizal plant Morella pensylvanica growing in sand dunes in coastal NJ (left). An actinorhizal root nodule (about 1.5 cm dia., center) and a phase contrast micrograph of Frankia sp. CpI1 showing spores and hyphae. (images by D. Benson)

Our current focus is on the nitrogen-fixing symbiosis between actinomycetes from the genus Frankia and angiosperms. A tour of the symbiosis can be found at the Frankia website that was assembled using funds from the NSF-USDA Joint Microbial Genome Sequencing program.

Our current efforts are directed at understanding the overall structure and characteristics of the Frankia genome compared to closely related organisms. We are attempting to tease out the genes that make Frankia unique and that enable the organism to enter into a symbiosis with higher plants. (top)

Cheese Microbiology

St. Nectaire cheese ripening in a cave in the Auvergne, France (top). The fungus Mucor that provides the "hairy" look to the cheese. (Sr. Noella Marcellino)

We have had an interest in traditional cheese ripening as viewed from the perspective of microbial ecology. Populations in ripening cheese appear and diminish according to a predictable pattern and depending on the natural environment, the milk source and the treatment accorded the curds prior to ripening.

We have studied the microbial diversity of the ripening process as a whole and viewed the molecular diversity of Geotrichum candidum one of the early inhabits of ripening cheese, in its natural habitats in the cheese caves of France. See the following articles for more information (top): Appl. Environ. Microbiol. 67:4752-4759; Appl. Environ. Microbiol. 58:3448-3454.

Tick Symbionts

Deer tick closeups. Tick body (top), mouth parts (middle), and close up of hypostome with bacteria in barbs (bottom). (D. Benson)

As part of our interest in microbial ecology, we have investigated the microorganisms associated with the black-legged tick, Ixodes scapularis, otherwise known as the deer tick. The deer tick is notorious for transmitting Lyme disease, particularly in the Northeastern part of the US. To assess the bacteria associated with deer ticks we use PCR amplification of 16S rRNA genes on whole macerated ticks. A variety of intracellular symbionts were detected that suggest that disease evolution in these animals is an ongoing problem that could potentially lead to the emergence of new disease as environmental changes continue to accumulate. For more information, read the article (top): Appl. Environ. Microbiol. 70:616-620.

Psychrophilic Bacteria