MSA - Ecology/Pathology
Duval, Lisabeth , Cantrell, Sharon A. .
Degradation of exopolymeric substances by the microbial communities from hypersaline microbial mats.
Microbial mats are self sustained organo-sedimentary structures where microbial communities position themselves according to nutrient availability creating a layered ecosystem. Fungi have been found to thrive in these ecosystems but their ecologic role is still poorly known. One of the possible roles of fungi in microbial mats is the degradation of the complex exopolymeric substances (EPS) produced by the mat communities. Samples were collected from two tropical hypersaline mat formations and slurries of each layer were enriched with xanthan gum (model EPS). EPS degradation was monitored for ten weeks from two culture types, one with antibiotics (the fungal community) and the other without antibiotics (full community). Monitoring was performed with the phenol-sulfuric and the alcian blue assays. Enrichments from the younger mat showed faster degradation against an EPS control than the more mature mat formation. Enrichments without antibiotics showed faster degradation in both formations, which suggests that the degradation is a product of a microbial consortium. DNA was extracted from the enrichment cultures and the ITS and 16S regions were amplified for Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis and compared to the natural microbial mat community. Preliminary data reveal a definite change through time in the microbial community in enrichment cultures. This suggests community preference for the EPS consumption. Isolates from the cultures have been sequenced including organisms as Hortaea werneckii, Pichia guilliermondi, Mycosphaerella sp., among others. This research shows the ability of fungi to grow and degrade EPS and provides an insight into their role inside microbial mats.
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1 - Universidad del Turabo, Department of Biology, School of Science and Technology , P.O. Box 3030, Gurabo, PR, 00778, Puerto Rico
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM