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, particularly focusing on viruses infecting oral bacteria. In this regard, we have studied the interaction between a bacterial virus that we previously isolated (bacteriophage φAa) and its host cell (Aggregatibacter actinomycetemcomitans), with human cells and tissues. Another bacteriophage that we are studying is phage φEf11. We originally isolated this virus by induction from a lysogenic endodontic isolate of Enterococcus faecalis. We have previously sequenced and annotated the complete genome of this virus. We are now exploring genetic engineering strategies in which this virus and its products, might be used therapeutically to control E. faecalis infections.
Dr. Hongming Zhang, Research Associate
Dr. Vijayalakshmi Iyer, Postdoctoral Research Associate
Dr. Eduardo Tinoco
State University of Rio de Janeiro
JM Tinoco, N Liss, H Zhang, R Nissan, W Gordon, L Sassone, R Stevens. Effect of genetically-engineered bacteriophage fEf11/fFL1C(D36)PnisA on dentin infection with antibiotic-resistant Enterococcus faecalis. Archives of Oral Biology, 82: 166-170, 2017.
JM Tinoco, B Buttaro, H Zhang, N Liss, L Sassone, R. Stevens. Effect of a genetically engineered bacteriophage on Enterococcus faecalis biofilms. Archives of Oral Biology, 71: 80-86, 2016.
RH Stevens, H Zhang, C Hsiao, S. Kachlany, EMB Tinoco, J DePew, DE Fouts. Structural proteins of Enterococcus faecalis bacteriophage fEf11. Bacteriophage. 6(4): 2016. DOI: 10.1080/21597081.2016.1251381.
RH Stevens. Transduction-mediated horizontal gene transfer in the oral microbiome. Frontiers in Cellular and Infection Microbiology, 5(12): 1-2, 10 February 2015, doi: 10.3389/fcimb.2015.00012
H Zhang, DE Fouts, J DePew, RH Stevens. Genetic modifications to temperate Enterococcus faecalis phage fEf11 that abolish the establishment of lysogeny and sensitivity to repressor, and increase host range and productivity of lytic infection. Microbiology, 159(6): 1023-1035, 2013. DOI 10.1099/mic0.067116-0.
RH Stevens, CM Lobo dos Santos, D. Zuanazzi, MB Mattos, DF Ferreira, SC Kachlany, EM Tinoco. Prophage induction in lysogenic Aggregatibacter actinomycetemcomitans cells co-cultured with human gingival fibroblasts, and its effect on leukotoxin release. Microbial Pathogen, 54: 54-59. 2013. http://dx.doi.org/10.1016/j.micpath.2012.09.005.
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.