Roy H. Stevens, DDS, MS
Henry Isaiah Dorr Professor, Department of Endodontology (Dental School)
Professor, Department of Microbiology and Immunology (School of Medicine)
Building 600, Rooms 362, 379, and 379A (2,200 square feet, total)
The Laboratory for Oral Infectious Diseases is a fully-equipped microbiology/molecular biology facility housing all the resources necessary for the growth, purification and analysis of oral microorganisms. A walk-in warm room/incubator allows the growth of large volumes of microbial cultures, and recovery/purification of cultured organisms is accomplished using the laboratory's superspeed and ultraspeed centrifuges, and tangential flow ultrafiltration system. Ultra cold freezers located in the laboratory are used for the preservation of the many stock cultures used in the research activities. Analytic equipment within the laboratory includes: electrophoresis systems (Agarose, SDS-PAGE, Western Transfer), a PCR thermal cycler, an electroporation system, a spectrophotometer, a UV DNA documentation system, and computers/printers. Specialized work areas, such as a dark room, a tissue culture room, and a sterile room are also attached to this laboratory. Supporting the activities of the laboratory are resources such as glassware processing equipment, a water purification system, a walk-in cold room, and a laboratory scale autoclave.
The focus of the activities in this laboratory is the study of infectious agents involved in oral diseases. Currently, we are studying two bacterial viruses that were isolated from induced lysogenic bacteria recovered from periodontal and endodontic infections, respectively. One of these bacteriophages, phage fAa, was isolated from a strain of the periodontal pathogen Aggregatibacter actinomycetemcomitans. Ongoing studies with this virus are investigating the interactions between phage fAa and its host cell (A. actinomycetemcomitans) with human cells and tissues. The other bacteriophage, phage φEf11, was induced from an endodontic isolate of Enterococcus faecalis. After recently sequencing and annotating the genome of this virus, we are now exploring ways in this this virus might be used therapeutically to control E. faecalis infections.
Dr. Hongming Zhang, Research Associate
Dr. Marcello Mattos, Visiting Research Scholar
Jason Cutrera, Laboratory Assistant
Dr. Eduardo Tinoco
State University of Rio de Janeiro
RH Stevens, MR Ektefaie, DE Fouts. The annotated complete DNA sequence of Enterococcus faecalis bacteriophage φEf11 and its comparison to all available phage and prophage genomes. FEMS Microbiol Lett, 317: 9-26, 2011.
DG Silva, RH Stevens, JMB Macedo, EMB Tinoco Presence of Helicobacter pylori in individuals with periodontal disease and upper gastric diseases. Archs Oral Biol. 55: 896-901, 2010.
RH Stevens, O Porras, A Delisle. Bacteriophages induced from lysogenic root canal isolates of Enterococcus faecalis. Oral Microbiol Immunol, 24:278-284, 2009.
R. Nissan, S.R. Makkar, M.N. Sela, and R. Stevens. Whole genomic DNA probe for Detection of Porphyromonas endodontalis. J. Endodontics. 26(4): 217-220, 2000.
E. M.B. Tinoco, R. Stevens, D. Haubek, C-H Lai, S. Balachandran, and H. Preus. The relationship of serotype, leukotoxin gene type, and lysogeny in Actinobacillus actinomycetemcomitans to periodontal disease status. European Journal of Oral Sciences. 105: 310-317, 1997.
R. H. Stevens, H.R. Preus, B. Dokko, D. Russell, D.H. Fine, D.H. Figurski, P Goncharoff and D. Furgang. The prevalence and distribution of bacteriophage øAa infection in strains of Actinobacillus actinomycetemcomitans. FEMS Microbiology Letters.119(3): 329-338, 1994.
R. Stevens, P. Goncharoff, D. Furgang, D. Fine, H. Schreiner and D. Figurski. Characterization and physical mapping of the genome of bacteriophage øAa from Actinobacillus actinomycetemcomitans. Oral Microbiology and Immunology. 8(2): 100-104, 1993.
R.H. Stevens, B.F. Hammond and D.H. Fine. Structural proteins of the Actinobacillus actinomycetemcomitans bacteriophage øAa. Oral Microbiology and Immunology. 5: 213-218, 1990.