Title: Archaea and Their Potential Role in Human Disease | Infection and Immunity
Headings: Archaea and Their Potential Role in Human Disease
Archaea and Their Potential Role in Human Disease
POTENTIAL PATHOGENICITY OF ARCHAEA
POTENTIAL ASSOCIATIONS OF ARCHAEA WITH HUMAN DISEASE
CONCLUSION AND FUTURE STUDIES
ACKNOWLEDGMENTS
REFERENCES
KEYWORDS

Content: The ubiquity of archaea in nature provides them ample opportunity for access to and colonization of susceptible hosts. In fact, we know of multiple niches for archaea in the human host. Methanogens, for example, have been identified among the human colonic ( 36 ), subgingival ( 1, 6, 29 ), and vaginal flora ( 2 ). Given their requirement for strictly anaerobic microenvironments, methanogens are likely to exist in human anatomic sites where well-characterized anaerobic bacteria flourish, possibly as coinhabitants. Specific surface interactions between host cells and archaea have not been characterized, nor have specific mechanisms involved in cell or tissue tropism. However, potential means for movement and attachment have been described. Unique flagella have been identified for many genera of archaea, and such flagella have more structural similarities to the type IV pili of bacteria than they do to bacterial flagella ( 55 ). Multiple archaeal genomes contain partial tad loci, which may encode Tad-like proteins involved in fibril formation and surface adherence ( 23 ). Pyrodictium species, which are disk-shaped hyperthermophilic crenarchaeotes, grow in culture as mycelium-like cell masses ( 33 ). A network of hollow flagellum-like filaments connects the Pyrodictium cells in a web-like arrangement, the purpose of which is unclear.