MARINE VIRUSES-VITAL ROLE EXPOSED-KEY TO NSF STUDY

TORONTO, Can. (BIO2002)--Responding to a surprising diversity of viruses in marine environments and the importance of the Chesapeake Bay to dense human populations nearby, the University of Maryland Biotechnology Institute and partners have launched the first comprehensive study of the Bay's viral and bacterial communities.

The study, funded by a $1 million grant from the National Science Foundation, establishes long-term microbial observatories to survey Bay waters year round and across its geographic and temperature ranges. Cooperating with UMBI in the study are the University of Delaware and the Smithsonian Environmental Research Center at Edgewater, Md.

"We know now that viruses are very abundant, that they are very important in regulating bacterial populations," explains Feng Chen, assistant professor at UMBI's Center of Marine Biotechnology. "Getting seasonal data for the first time will allow us to see how viral and bacterial communities change over a year."

Chen says that the use of modern molecular techniques in studying the interaction of viruses and bacteria has become a critically important aspect of marine ecology. For the study, such tools are essential because only one percent of the bacterial community can be cultured. "This is a real challenge for marine microbial ecologists. We know they are there; we just can't culture them," Chen explains.

There are a million bacteria and ten million viruses in one teaspoon of coastal waters such as the Chesapeake Bay. A majority of natural virus communities, says Chen, are made of bacteriophages, as bacteria are the dominant host in aquatic environments. "Many recent studies have shown that marine viruses play an important role in keeping microbial world balanced. They are responsible for a significant portion of bacterial mortality," comments Chen.

In addition, viruses influence the genetic diversity of microbial communities by genetic exchanges (through DNA transduction, transformation, and lysogenic conversion). Chen recently sequenced a whole genome of an important marine virus and "I found out there is definitely some area of exchange with the host".

The Bay study will form a much needed baseline, he says, to properly assess pollution in high population areas, such as the Inner Harbor in Baltimore, or toxic algae blooms in tributaries, often associated with fish kills and suspected human health problems.

Preliminary data of the microbial study of the Chesapeake Bay indicates that viral and bacterial communities are much more dynamic temporally than spatially. Much more data are needed in order to better understand the seasonal and spatial variation or co-variation of microbial communities in the bay. Although the study has only begun this year, Chen hopes that microbial community fingerprints can serve as biosensors of marine environmental change.

"Nobody has tried it before. But when we know what kind of microbial community can co-exist with toxic algae blooms, for example, we could know if conditions are right for a particular bloom season, particular disease outbreak seasons. We don't know the whole microbial ecology of those situations yet," he says.

# # #

The University of Maryland Biotechnology Institute was mandated by the state of Maryland legislature in 1985 as "a new paradigm of state economic development in biotech-related sciences." With five major research and education centers across Maryland, UMBI is dedicated to advancing the frontiers of biotechnology. The centers are the Center for Advanced Research in Biotechnology in Rockville; Center for Agricultural Biotechnology in College Park; and Center of Marine Biotechnology, Medical Biotechnology Center, and the Institute of Human Virology, all in Baltimore.