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Microbiology & Immunology Faculty
Research | Publications | Lab Members | Curriculum vitae (Pdf format) | Biosketch (Pdf format)
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Joel B. Baseman, Ph.D.
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Research
Mycoplasma pneumoniae (MPN) is among the most common bacterial pathogens causing human respiratory diseases. It is the etiologic agent of primary atypical pneumonia and is also responsible for a spectrum of other acute respiratory infections, such as tracheobronchitis, bronchiolitis, pharyngitis, and croup. It accounts for 20-30% of all community acquired pneumonia. MPN has also been implicated in chronic airway diseases, such as asthma, and extrapulmonary pathologies, which have been described through an extensive literature over many years. MPN is among the smallest self-replicating cells (816 kb genome) and is spread by direct contact or aerosol among individuals, usually young children and adolescents, although the age spectrum for susceptibility includes adults and the elderly. Still, a straightforward cause-and-effect relationship between MPN and disease pathogenesis has remained challenging, mainly because of the lack of definable MPN virulence determinants that can be directly linked to inflammation, pulmonary dysfunction and airway disease progression. It is also clear that MPN infections and associated pathologies are greatly underreported because of difficulties in cultivating these pathogens directly from clinical specimens; inadequate diagnostic tests; and the wide diversity of clinical manifestations associated with MPN infections. Our recent identification and characterization of a unique MPN toxin represents the first authentic toxin found among all pathogenic mycoplasmas, and appears to be a bona fide ADP-ribosylating (and vacuolating) toxin, like the classical ADP-ribosylating toxins of pertussis, diphtheria etc. The roles that MPN and toxin, designated Community Acquired Respiratory Distress Syndrome (CARDS) toxin, play in acute and chronic airway diseases will be discussed, including the possibility that the dissection of biological, biophysical and immunomodulatory properties of the CARDS TX may uncover diagnostic, prognostic and therapeutic targets for the clinical management and prevention of MPN-mediated airway diseases.
In parallel studies, we are examining the sexually transmitted mycoplasma pathogen, Mycoplasma genitalium (MGN), which is the smallest (580kb genome) self-replicating cell and is the cause of urethritis and a range of other genitourinary pathologies. We are clarifying MGN virulence determinants and dynamic interactions between MGN and human target cells that lead to overt clinical disease. Recently, we described the remarkable ability of MGN to exhibit intranucleolar localization, suggesting that this pathogen circumvents host defenses and navigates through host cell structures in order to establish and maintain viability and persistence. Specific gene products of MGN that contribute to this unique trafficking might provide insights as to how this pathogen circumvents host defenses and navigates through host cell structures in order to establish and maintain viability and persistence. Specific gene products of MGN that contribute to this unique trafficking might provide insights as to how this pathogen maneuvers in vivo with pathogenetic consequences.
Publications
- Kannan, T.R. and J.B. Baseman. 2006. ADP-ribosylating and vacuolating cytotoxin of Mycoplasma pneumoniae represents unique virulence determinant among bacterial pathogens. Proc. Natl. Acad. Sci. USA 103:6724-6729.
- Musatovova, O., S. Dhandayuthapani and J.B. Baseman. 2006. Transcriptional heat-shock response in the smallest known self-replicating cell, Mycoplasma genitalium. J. Bact. 188:2845-2855.
- Stein, M.A. and J.B. Baseman. 2006. The evolving saga of Mycoplasma genitalium. Clin. Micro. Newsletter 28:41-48.
- Korte, J.E., J.B. Baseman, M.P. Cagle, C. Herrera, et al. 2006. Cervicitis and genitourinary symptoms in women culture positive for Mycoplasma genitalium. Am. J. Reprod. Immunol. 55:265-275.
- Musatovova, O., C. Herrera and J.B. Baseman. 2006. Proximal region of the gene encoding cytadherence-related protein permits molecular typing of Mycoplasma genitalium clinical strains by PCR-restriction fragment length polymorphism. J. Clin. Microbiol. 44:598-603.
- Kannan, T.R., D. Provenzano, J.R. Wright and J.B. Baseman. 2005. Identification and characterization of human surfactant protein-A binding protein of Mycoplasma pneumoniae. Infect. Immun. 73:2828-2834.
- Blaylock, M.W., O. Musatovova, J.G. Baseman and J.B. Baseman. 2004. Determination of infectious load of Mycoplasma genitalium in clinical samples of human vaginal cells. J. Clin. Micro. 42:746-752.
- Baseman, J.B., M. Cagle, J.E. Korte, C. Herrera, W.G. Rasmussen, J.G. Baseman, R. Shain and J.M. Piper. 2004. Diagnostic assessment of Mycoplasma genitalium in culture-positive women. J. Clin. Micro. 42:203-211.
- Musatovova, O., S. Dhandayuthapani and J.B. Baseman. 2003. Transcriptional starts for cytadherence-related operons of Mycoplasma genitalium. FEMS Micro. Letters. 229:73-81.
- Alvarez, R.A., M.W. Blaylock and J.B. Baseman. 2003. Surface localized glyceraldehyde-3-phosphate dehydrogenase of Mycoplasma genitalium binds mucin. Molec. Micro. 48:1417-1425.
- Dallo, S.F., T.R. Kannan, M.W. Blaylock and J.B. Baseman. 2002. Elongation factor Tu and E1 β subunit of pyruvate dehydrogenase complex act as fibronectin binding proteins in Mycoplasma pneumoniae. Molec. Micro. 46:1041-1051.
Lab Members
Lab Rooms: 5.029V, 5.033V
- Marianna Cagle, Special Research Coordinator
- Brandon Guin, Lab Technician Assistant III
- T. R. Kannan, Ph.D., Asst. Professor/Research
- Linbo Li, Research Fellow
- Krishnan Manickam, Ph.D., Postdoctoral Fellow
- Oxana Musatovova, Ph.D., Instructor/Research
- Sowmya Balasubramanian, Ph.D., Postdoctoral Fellow
- Oscar Quijada Pich, Ph.D., Postdoctoral Fellow
- Sudha Somarajan, Ph.D., Postdoctoral Fellow
Graduate Students:
Coreen Johnson
Wenbo Zhang