No abstract

A bacterium, CP1, identified as Pseudomonas putida strain, was investigated for its ability to grow on and degrade mono-chlorophenols and phenols as sole carbon sources in aerobic shaking batch culture. The organism degraded up to 1.56 mM 2- and 3-chlorophenol, 2.34 mM 4-chlorophenol and 8.5 mM phenol using an ortho-cleavage pathway. P. putida CP1, acclimated to degrade 2-chlorophenol, was capable of 3-chlorocatechol degradation, while P. putida, acclimated to 4-chlorophenol degradation, degraded 4-chlorocatechol. Growth of P. putida CP1 on higher concentrations of the mono-chlorophenols, >or=1.56 mM 4-chlorophenol and >or=0.78 mM 2- and 3-chlorophenol, resulted in decreases in cell biomass despite metabolism of the substrates, and the formation of large aggregates of cells in the culture medium. Increases in cell biomass with no clumping of the cells resulted from growth of P. putida CP1 on phenol or on lower concentrations of mono-chlorophenol. Bacterial adherence to hydrocarbons (BATH) assays showed cells grown on the higher concentrations of mono-chlorophenol to be more hydrophobic than those grown on phenol and lower concentrations of mono-chlorophenol. The results suggested that increased hydrophobicity and autoaggregation of P. putida CP1 were a response to toxicity of the added substrates.

Facilitative UT-B urea transporters have been shown to play an important role in the urinary concentrating mechanism. Recent studies have now suggested a link between UT-B allelic variation and human bladder cancer risk. UT-B1 protein has been previously identified in the bladder of various mammalian species, but not yet in humans. The aim of the present study was to investigate whether any UT-B protein was present in the human bladder. First, RT-PCR results confirmed that UT-B1 was strongly expressed at the RNA level in the human bladder, whereas UT-B2 was only weakly present. Initial Western blot analysis confirmed that a novel UT-B COOH-terminal antibody detected human UT-B proteins. Importantly, this antibody detected a specific 40- to 45-kDa UT-B signal in human bladder protein. Using a peptide-N-glycosidase F enzyme, this bladder UT-B signal was deglycosylated to a core 30-kDa protein, which is smaller than the predicted size for UT-B1 but similar to many proteins reported to be UT-B1. Finally, immunolocalization experiments confirmed that UT-B protein was strongly expressed throughout all urothelium layers except for the apical membrane of the outermost umbrella cells. In conclusion, these data confirm the presence of UT-B protein within the human bladder. Further studies are now required to determine the precise nature, regulation, and physiological role of this UT-B.

A mixed microbial community, specially designed to degrade a wide range of substituted aromatic compounds, was examined for its ability to degrade mono-chlorophenols as sole carbon source in aerobic batch cultures. The mixed culture degraded 2-, 3-, and 4-chlorophenol (1.56 mM) via a meta- cleavage pathway. During the degradation of 2- and 3-chlorophenol by the mixed culture, 3-chlorocatechol production was observed. Further metabolism was toxic to cells as it led to inactivation of the catechol 2,3-dioxygenase enzyme upon meta- cleavage of 3-chlorocatechol resulting in incomplete degradation. Inactivation of the meta- cleavage enzyme led to an accumulation of brown coloured polymers, which interfered with the measurement of cell growth using optical density. Degradation of 4-chlorophenol by the mixed culture led to an accumulation of 5-chloro-2-hydroxymuconic semialdehyde, the meta- cleavage product of 4-chlorocatechol. The accumulation of this compound did not interfere with the measurement of cell growth using optical density. 5-chloro-2-hydroxymuconic semialdehyde was further metabolized by the mixed culture with a stoichiometric release of chloride, indicating complete degradation of 4-chlorophenol by the mixed culture via a meta- cleavage pathway.

A bacterium, CP1, identified as Pseudomonas putida strain, was investigated for its ability to grow on and degrade mono-chlorophenols and phenols as sole carbon sources in aerobic shaking batch culture. The organism degraded up to 1.56 mM 2- and 3-chlorophenol, 2.34 mM 4-chlorophenol and 8.5 mM phenol using an ortho-cleavage pathway. P. putida CP1, acclimated to degrade 2-chlorophenol, was capable of 3-chlorocatechol degradation, while P. putida, acclimated to 4-chlorophenol degradation, degraded 4-chlorocatechol. Growth of P. putida CP1 on higher concentrations of the mono-chlorophenols, >or=1.56 mM 4-chlorophenol and >or=0.78 mM 2- and 3-chlorophenol, resulted in decreases in cell biomass despite metabolism of the substrates, and the formation of large aggregates of cells in the culture medium. Increases in cell biomass with no clumping of the cells resulted from growth of P. putida CP1 on phenol or on lower concentrations of mono-chlorophenol. Bacterial adherence to hydrocarbons (BATH) assays showed cells grown on the higher concentrations of mono-chlorophenol to be more hydrophobic than those grown on phenol and lower concentrations of mono-chlorophenol. The results suggested that increased hydrophobicity and autoaggregation of P. putida CP1 were a response to toxicity of the added substrates.