Microbial dechlorination of historically present and freshly spiked chlorinated dioxins and diversity of dioxin-dechlorinating populations

Article Abstract:

Microbial activity changes from methanogenic to nonmethanogenic during dechlorination of polychlorinated dibenzo-p-dioxins (PCDDs) and aged tri- and monoCDD congeners. The peri-dechlorination pathway of 2,3,7,8-substituted hepta- to pentaCDDs produces 2,3,7,8-tetraCDD. Another dechlorination pathway is the peri- lateral pathway of non-2,3,7,8-substituted congeners. Peri and triCDD dechlorination occur due to the activity of nonmethanogenic, non-spore-forming microbial subpopulations. Both freshly spiked and aged PCDDs undergo microbial reductive dechlorination.

Observations, Dioxin, Dioxins

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Enzymatic pathway for the bacterial degradation of the cyanobacterial cyclic peptide toxin microcystin LR

Article Abstract:

The degradation of microcystin LR, a cynobacterial cyclic peptide toxin by Sphingomonas species involves three intracellular hydrolytic enzymes. The enzyme microcystinase opens the stable cyclic peptide and prevents its reactions with the protein phosphatase. This makes microcystin LR non toxic. The intermediates of the reaction are a linearized microcystin LR and a tetrapeptide.

Microbial enzymes, Toxins

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Cellular microcystin content in N-limited Microcystis aeruginosa can be predicted from growth rate

Article Abstract:

A model is presented on the production and development of microcystins (MCYSTs), or cyclic heptapeptide toxins, from nitrogen-limited Microcystis aeruginosa cyanobacterium cultures. The model includes categories for MCYST/dry weight ratio and MCYST/protein ratio; fast-growing N-limited M. aeruginosa cells are found to be smaller and have a lower mass than slow-growing cells.

Australia, Statistical Data Included, Models, Environmental aspects, Cyanobacteria, Cell research, Cytological research, Microbial toxins, Bacteriology

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