Background and Research Interests

Dr. Jenifer Turco received her M.S. in Biology and her Ph.D. in Medical Microbiology from West Virginia University. She then did postdoctoral research at the University of South Alabama. Dr. Turco’s professional interests include microbiology, immunology, and infectious diseases. Her research focuses on Rickettsia prowazekii, an obligate intracellular bacterium that causes epidemic typhus in humans.

R. prowazekii is transmitted by human body lice; thus, outbreaks of disease due to this organism have been associated with poor hygiene, overcrowding, and other living conditions that promote body louse infestation. At present, louse-borne typhus is most likely an underreported disease. However, it has been documented in parts of Africa, Asia, and Latin America during the past two decades. In the United States, flying squirrels may harbor R. prowazekii bacteria, and there have been sporadic cases of flying squirrel-associated typhus in humans.

Within the human body, R. prowazekii grows mainly inside the endothelial cells that line the small blood vessels, although the organism can also grow within macrophages. R. prowazekii bacteria may persist in individuals who recover from typhus and later cause an illness known as Brill-Zinsser disease (recrudescent typhus).

Dr. Turco is studying how cytokines such as interferons and tumor necrosis factor alpha limit the intracellular growth of rickettsiae and thus contribute to defending the host against the rickettsiae. Questions being addressed include:

(1) What are the cellular signaling pathways through which these cytokines induce their antirickettsial effects?

(2) Is rickettsial growth inhibited in cytokine-treated host cells because the rickettsiae cannot obtain required nutrients such as nucleotides and iron?

(3) How do cytokine-resistant R. prowazekii isolates avoid the antirickettsial effects of cytokines?

Selected Publications

Turco, J., and H. H. Winkler. 1991. Comparison of properties of virulent, avirulent, and interferon-resistant Rickettsia prowazekii strains. Infect. Immun. 59:1647-1655.

Gao, Q., J. Turco, and H. H. Winkler. 1993. Synthesis of DNA, rRNA, and protein by Rickettsia prowazekii growing in untreated or gamma interferon-treated mouse L929 cells. Infect. Immun. 61:2383-2389.

Winkler, H. H., L. C. Day, R. M. Daugherty, and J. Turco. 1993. Effect of gamma interferon on phospholipid hydrolysis and fatty acid incorporation in L929 cells infected with Rickettsia prowazekii. Infect. Immun. 61:3412-3415.

Turco, J., and H. H. Winkler. 1993. Role of the nitric oxide synthase pathway in the inhibition of growth of interferon-sensitive and interferon-resistant Rickettsia prowazekii strains in L929 cells treated with tumor necrosis factor alpha and gamma interferon. Infect. Immun. 61: 4317-4325.

Turco, J., and H. H. Winkler. 1994. Relationship of tumor necrosis factor alpha, the nitric oxide synthase pathway, and lipopolysaccharide to the killing of gamma interferon-treated macrophagelike RAW264.7 cells by Rickettsia prowazekii. Infect. Immun. 62: 2568-2574.

Turco, J., and H. H. Winkler. 1994. Cytokine sensitivity and methylation of lysine in Rickettsia prowazekii EVir and interferon-resistant Rickettsia prowazekii strains. Infect. Immun. 62: 3172-3177.

Turco, J., and H. H. Winkler. 1997. Cytokines influencing infections by Rickettsia species, p. 29-52. In B. Anderson, H. Friedman, and M. Bendinelli (ed.), Rickettsial Infection and Immunity. Plenum Publishing Corp., New York.

Turco, J., H. Liu, S. F. Gottlieb, and H. H. Winkler. 1998. Nitric oxide-mediated inhibition of the ability of Rickettsia prowazekii to infect mouse fibroblasts and mouse macrophagelike cells. Infect. Immun. 66: 558-566.

Turco, J., and M. Byrd. 2001. An interdisciplinary perspective: infectious diseases and history. American Biology Teacher 63: 325-335.

Turco, J. 2005. Rickettsia prowazekii-infected, cultured human fibroblasts. Microbe Library (American Society for Microbiology) [Online]. Available: http://www.microbelibrary.org.

The image is a light micrograph of R. prowazekii-infected, cultured human fibroblasts that were stained by the Giménez method.