Production of exopolysaccharides by Antarctic marine bacterial isolates.

AIMS: This study was undertaken to examine and characterize Antarctic marine bacterial isolates and the exopolysaccharides (EPS) they produce in laboratory culture. METHODS AND RESULTS: Two EPS-producing bacterial strains CAM025 and CAM036 were isolated from particulate material sampled from seawater and sea ice in the southern ocean. Analyses of 16S rDNA sequences placed these isolates in the genus Pseudoalteromonas. In batch culture, both strains produced EPS. The yield of EPS produced by CAM025 was 30-fold higher at -2 and 10 degrees C than at 20 degrees C. Crude chemical analyses showed that these EPS were composed primarily of neutral sugars and uronic acids with sulphates. Gas chromatographic analysis of monosaccharides confirmed these gross compositional findings and molar ratios of monosaccharides revealed differences between the two EPS. CONCLUSIONS: The EPS produced by Antarctic bacterial isolates examined in this study appeared to be polyanionic and, therefore, 'sticky' with respect to cations such as trace metals. SIGNIFICANCE AND IMPACT OF THE STUDY: As the availability of iron as a trace metal is of critical importance in the southern ocean where it is know to limit primary production, the role of these bacterial EPS in the Antarctic marine environment has important ecological implications.

Characterization of glycosaminoglycans in urine from patients with nephrotic syndrome and control subjects, and their effects on lipoprotein lipase.

Previously we found that alpha 2-acid glycoprotein fraction from urine of patients with the nephrotic syndrome stimulated the lipoprotein lipase reaction in vivo and in vitro. The activator was separated from the alpha 1-acid glycoprotein and identified as a glycosaminoglycan. The studies reported here were undertaken to characterize and quantify the glycosaminoglycans contained in urine of patients with the nephrotic syndrome and to compare these to the glycosaminoglycans in urine of the control subjects. We found that free low molecular weight glycosaminoglycans, heparan sulfate and chondroitin 4-sulfate, are excreted in both patients with the nephrotic syndrome and controls however, patients with the nephrotic syndrome excreted much less of both glycosaminoglycans. The free form of heparan sulfate was found to be the activator which stimulated the lipoprotein lipase reaction in vitro in the presence of apolipoprotein CII. In addition, the urine from patients with the nephrotic syndrome contained a protein-glycosaminoglycan complex which was absent in control urine. Glycosaminoglycans in the complex could be released by papain digestion or by trichloroacetic acid. Our evidence indicates that this glycosaminoglycans fraction is a law charge form of chondroitin sulfate.