fundyense filtrate. These results demonstrate that competitor cell size, independent from taxonomy, may influence the outcome of allelopathic interactions. The findings presented here suggest a potential ecological impact of diatom cell size reduction and sexual reproduction that has not yet been described and that may be important in determining diatom survival and success. “
“In wetland habitats, periphyton is a common component of open-water areas with species assemblage determined by local water quality. Extracellular polymeric substances (EPS) secreted by algae and bacteria give structure to periphyton, and differences in EPS chemistry

affect the functional roles of these polymers. The Florida Everglades provide a unique opportunity to study compositional differences of Metabolism inhibitor EPS from Selleck ABT 199 distinctive algal assemblages that characterize areas of differing water chemistry. Water conservation area (WCA)-1 is a soft-water impoundment; periphyton was loosely associated with Utricularia stems and amorphous in structure, with a diverse desmid and diatom assemblage, and varying cyanobacterial abundance. Extracellular polymers were abundant and were loosely cell-associated sheaths and slime layers in addition to tightly cell-associated capsules. The EPS were

complex heteropolysaccharides with significant saccharide residues of glucose, xylose, arabinose, and fucose. Carboxylic acids were also prominent, while ester sulfates and proteins were small components. Structured, cohesive cyanobacteria-dominated periphyton was observed in WCA-2A, a minerotrophic impoundment, and filaments were heavily encrusted with calcium carbonate and detrital matter. 上海皓元 EPS were primarily cell-associated sheaths, and polymer residues were dominated by glucose, xylose, fucose, and galactose, with uronic acids also a significant component of the polymers. Principal components analysis revealed that periphyton community assemblage determined the monosaccharide composition of EPS, which ultimately

determines a range of biogeochemical processes within the periphyton. “
“The genera Esoptrodinium Javornický and Bernardinium Chodat comprise freshwater, athecate dinoflagellates with an incomplete cingulum but differing reports regarding cingulum orientation and the presence of chloroplasts and an eyespot. To examine this reported diversity, six isolates were collected from different freshwater ponds and brought into clonal culture. The isolates were examined using LM to determine major cytological differences, and rDNA sequences were compared to determine relatedness and overall phylogenetic position within the dinoflagellates. All isolates were athecate with a left-oriented cingulum that did not fully encircle the cell, corresponding to the current taxonomic concept of Esoptrodinium. However, consistent cytological differences were observed among clonal isolates.