Seth Bordenstein: Phage Wormholes To Dwell in the Bacterial and Eukaryotic Worlds
Channel: Dr. Seth Bordenstein
Date: 2015-10-14

On October 6, 2015 in the Department of Plant and Microbial Biology at North Carolina State University, Dr. Bordenstein presented a seminar entitled "Phage Wormholes: Hacking Symbiosis To Dwell in the Bacterial and Eukaryotic Worlds". Topics spanned genome evolution, microbial ecology, antibiotic discovery in Archaea, and generally symbioses between animals, intracellular bacteria (Wolbachia), and bacteriophages. 

Brief Synopsis: All viruses are engaged in a competitive arms race with their hosts for survival, resulting frequently in significant coevolution. Thus, modes of cellular entry and exit are definitive and often specific properties of a virus and generally correlate with the cellular domain of their host. For example, the majority of bacterial viruses, or phages, utilize tail-like structures to recognize and penetrate their bacterial hosts and regularly encode a lytic cassette consisting of a holin, an endolysin and spanins to rupture and exit host membranes. Eukaryotic viruses, on the other hand, access the cytoplasm either by membrane fusion or membrane disruption depending on the presence or absence of a viral envelope, respectively. They generally deploy exit strategies such as budding or exocytosis rather than cellular lysis, although some are known to induce apoptosis as a means to release progeny into the extracellular matrix.

Viruses of obligate intracellular bacteria are curiously encompassed by both bacterial and eukaryotic membranes and therefore possess an enigmatic two-fold challenge. They must not only breach peptidoglycan and permeabilize bacterial membranes, but they also have to cross the eukaryotic membrane(s) that encapsulates the bacteria as well as the eukaryotic cytoplasm or extracellular matrix that they encounter upon bacterial lysis. To the best of our knowledge, no study in virology has assessed the potential for viruses to traverse multiple cellular domains of life. Do these viruses thrive with standard bacteriophage genes or do they utilize a novel strategy that transcends contemporary virus demarcations?