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Biomedical subjects

B J Brown

Publications and source records attributed to B J Brown.

At least 19 recordsLinked to original sources
PubMed1991

L-guluronan-specific alginate lyase from a marine bacterium associated with Sargassum.

The major extracellular alginate lyase activities secreted by a Gram-negative, facultative bacterium associated with actively growing Sargassum fluitans have been resolved an examined for substrate specificity. A fraction excluded from Sephadex G-75 was equally active toward (1----4)-beta-D-mannuronan, (1----4)-alpha-L-guluronan, and alginate with the formation of di- and tri-saccharides as apparent limit products and oligo-saccharides indicative of an endolytic mechanism. A second fraction which was included during G-75 filtration was inactive toward D-mannuronan and 4 times more active toward L-guluronan than native alginate. Proton magnetic resonance spectrometry identified the primary product of this enzyme as O-(4-deoxy-alpha-L-erythro-hex-4-enopyranosyluronic acid)-(1----4)-O-(alpha-L-gulopyranosyluronic acid)-(1----4)-O-alpha-L-gulopyranuronic acid. The L-guluronan-specific enzyme requires 0.5 M NaCl for maximal activity and has been purified as a monomeric protein having an apparent molecular mass of 38 kD and an approximate pI of 4.5. The predominant formation of trisaccharide over the course of a reaction showed a primarily exolytic mechanism, indicating an enzyme activity unique from any previously reported.

Carbohydrate Sequence↗
PubMed1991

Cloning of alginate lyase gene (alxM) and expression in Escherichia coli.

The alxM gene encoding a D-mannuronan-specific alginate lyase has been cloned from a marine bacterium isolated as an epiphyte on the brown alga, Sargassum fluitans. Expression of this gene in Escherichia coli provides a source of this enzyme for probing alginate structure and modifying the mannuronan-rich alginate polymers produced by bacterial pathogens.

Blotting, Southern↗
PubMed1979

Uncontrollable postpartum bleeding: a new approach to hemostasis through angiographic arterial embolization.

A case of severe postpartum hemorrhage is reported. Three separate surgical procedures failed to reveal the source of bleeding, and standard surgical techniques, including bilateral ligation of the hypogastric arteries, were unsuccessful in producing hemostasis. However, angiography successfully identified the specific bleeding vessel, and transcatheter embolization with Gelfoam fragments quickly and effectively stopped the hemorrhage. The authors consider angiographic embolization to be an effective alternative approach to the control of pelvic hemorrhage and recommend that the technique be considered prior to surgical intervention.

Adult↗