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One is disease and one of the most destructive pathogens in aquaculture is Flavobacterium columnare (F. columnare) sometimes called simply Columnaris Disease or CD.
The disease is widespread and represents a major hurdle to commercial fish farming. In 2002, for example, more than 50 percent of channel catfish producers reported incidences of CD in their adult grow-out ponds and the disease accounted for 45.2 percent of total losses of fry and fingerlings. Because of the economic importance of aquaculture, especially with the decline of certain wild fish stocks, the federal government would love to see a vaccine to battle the disease but first some basic research has to be done.
That's where Andrew Staroscik, a post-doc who has been working with Dr. David R. Nelson of the CELS Department of Cell and Molecular Biology, comes in.
Staroscik received his PhD from the Graduate School of Oceanography after getting his masters in economics from Boston University. He spent a couple years in the Peace Corps, and did some work for an engineering company before coming to URI where he was hired on earmark biotechnology funding.
Tackling the common disease that affects fish in aquaculture was not easy. "It was a challenge to take on this project," says Staroscik. "It was a risky project. Many others had tried and failed to get a genetic system working for F. columnare."
After about two and a half years, Staroscik said he has succeeded in modifying existing techniques to really get an understanding of the pathogen.
And the pathogen does quite a job on fish.
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People with aquaria may be familiar with Columnaris Disease which is sometimes dubbed "cottonmouth disease" because the bacteria can form a whitish mucus in the mouths of fish.
The disease is also called saddleback disease and often involves lesions affecting the gills, skin and fins.
Fish that get the disease are usually stressed by overcrowding, extremely warm water temperatures, low oxygen levels, high ammonia and nitrite levels-conditions often found in aquaculture. The disease can also affect wild fish-channel catfish in southern rivers are susceptible in summer months.
In aquaculture an outbreak of the disease can have disastrous results because the fish are in close confinement and water is sometimes recirculated.
"Very little is known about the disease," says Staroscik, but the basic research he has done to understand the pathogen he terms as "intellectually very satisfying."
F. columnare, explains Staroscik, is only distantly related to the bacteria with the best developed manipulation systems so established mutagenesis systems needed to be adopted to be successful in this group.
"Techniques for the introduction of foreign DNA into other Flavobacterium species, F. johnsoniae, had been developed more than 10 years ago. Despite substantial effort by others, we are the first to succeed in modifying these techniques to work in F. columnare," says Staroscik.
In two years of working with the organism, we have succeeded in transferring foreign DNA into multiple F. columnare strains, we have generated
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strains of F. columnare that express green fluorescent protein allowing the cells to be visualized using epifluorescent microscopy and we have begun to characterize some of the behaviors of the bacteria that may be important to their ability to cause disease. These include motility, biofilm formation and the secretion of degradative enzymes," he continues.
"These accomplishments have deepened our understanding of the F. columnare and will help lead to the development of effective vaccines against this economically important pathogen."
All of this would not have been possible at URI without the earmark funding. "The earmark funding gave Dave (Nelson) and me the ability to take on this risky project." said Staroscik. "Thanks to the funding, we're been able to make some major contributions to the field."
Staroscik, whose wife works as a biologist at Roger Williams University, is nearing the end of his funding but he hopes the work he has done will be carried on at URI. Nelson said there is a possibility of Staroscik landing another position at URI but it may not be on this particular project.
Nelson said he will keep sending in proposals seeking more funding on the project but failing that, he may need to use graduate students to continue the work-it simply will take longer to make progress because grad students, who have to take courses, cannot devote as much time as a post-doc can.
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