Detection of GroEL in activated sludge: a model for detection of system stress

Duncan, A. J.; Bott, Charles; Terlesky, Katherine C.; Love, Nancy G.

doi:10.1046/j.1472-765x.2000.00641.x

Cited by 16 publications

(6 citation statements)

References 24 publications

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“…Activated genes include dnaK (PP4727), groEL (PP1361), and a variety of chaperones and proteases (PP0625, PP1360, PP1982, PP2302, PP4728, PP5000 and PP5001) (Table 2). GroEL was shown to be a general stress response protein that is rapidly produced in activated sludge exposed to stress (Duncan et al. , 2002).…”

Section: Resultsmentioning

confidence: 99%

Physiological responses of Pseudomonas putida to formaldehyde during detoxification

Roca

Rodríguez-Herva

Duque

et al. 2007

Microbial Biotechnology

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SummaryPseudomonas putida KT2440 exhibits two formaldehyde dehydrogenases and two formate dehydrogenase complexes that allow the strain to stoichiometrically convert formaldehyde into CO2. The strain tolerated up to 1.5 mM formaldehyde and died in the presence of 10 mM. In the presence of 0.5 mM formaldehyde, a sublethal concentration of this chemical, the growth rate decreased by about 40% with respect to growth in the absence of the toxicant. Transcriptomic analysis revealed that in response to low formaldehyde concentrations, a limited number of genes (52) were upregulated. Based on the function of these genes it seems that sublethal concentrations of HCOH trigger responses to overcome DNA and protein damage, extrude this toxic compound, and detoxify it by converting the chemical to CO2. In strains bearing mutations of the upregulated genes we analysed growth inhibition by 1.5 mM HCOH and killing rates by 10 mM HCOH. Mutants in the MexEF/OprN efflux pump and in the DNA repair genes recA and uvrB were hypersensitive to 10 mM HCOH, the killing rate being three to four orders of magnitude higher than those in the wild‐type strain. Mutants in other upregulated genes died at slightly higher or at similar rates to the parental strain. Regarding growth inhibition, we found that mutants in glutathione biosynthesis, stress response mediated by 2‐hydroxy acid dehydrogenases and two efflux pumps of the MSF family were unable to grow in the presence of 1.5 mM HCOH. In an independent screening test we searched for mutants which were hypersensitive to formaldehyde, but whose expression did not change in response to this chemical. Two mutants with insertions in recD and fhdA were found which were unable to grow in the presence of 1.5 mM HCOH. The recD mutant was hypersensitive to 10 mM HCOH and died at a higher rate than the parental strain.

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Section: Resultsmentioning

confidence: 99%

Physiological responses of Pseudomonas putida to formaldehyde during detoxification

Roca

Rodríguez-Herva

Duque

et al. 2007

Microbial Biotechnology

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“…However, much in the way of fundamental expression analysis and comparative genomics is required before we are in a position to interpret gene expression data from environmental samples in a comprehensive manner. Analysis of gene expression in complex microbial communities at the level of proteins has already been tested using traditional biochemical approaches (Duncan et al ., 2000; Bott et al ., 2001), but the application of the tools of proteomics (e.g. two‐dimensional gel electrophoresis coupled with matrix‐assisted laser desorption ionization–time of flight MS and other mass spectrometric techniques) is set to increase the quantity and quality of information on gene expression that can be obtained from complex microbial communities.…”

Section: Discussionmentioning

confidence: 99%

Linking genetic identity and function in communities of uncultured bacteria

Gray

Head

2001

Environmental Microbiology

110

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“…The authors are investigating the mechanisms associated with wastewater-treatment process upset caused by shock loads of toxic chemicals Bott et al, 1998 andDuncan et al, 2000). The underlying hypothesis of this research states that microorganisms in biological treatment systems adapt physiologically to toxic shock events by activating microbial stress responses, and these responses play a significant role in treatment process deterioration.…”

Section: Introductionmentioning

confidence: 99%

Investigating a Mechanistic Cause for Activated‐Sludge Deflocculation in Response to Shock Loads of Toxic Electrophilic Chemicals

Bott

Love²

2002

Water Environment Research

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It is hypothesized that a physiological bacterial stress response mechanism, called the glutathione-gated potassium efflux system, is a significant contributor to activated-sludge deflocculation caused by shock loads of toxic electrophilic chemicals. The results show significant potassium (K ϩ ) efflux from activated sludge flocs to the bulk liquid in response to sublethal (concentrations less than that required to reduce the specific oxygen uptake rate by 50%) shock loads of chloro-2,4-dinitrobenzene, N-ethylmaleimide, 2,4-dinitrotoluene, benzoquinone, and cadmium in a bench-scale sequencing batch reactor system. Electrophile-induced K ϩ efflux was correlated with significant deflocculation, as measured by an increase in effluent volatile suspended solids. The K ϩ efflux occurred immediately (within minutes) after toxin addition and preceded the observed increase in effluent turbidity. The transport of other cations, including sodium, calcium, magnesium, iron, and aluminum, either to or from the floc structure, was negligible as compared with K ϩ efflux, and cell lysis was determined to be minimal at the chemical shock loads applied. The current results are the first to suggest that activated-sludge upset (i.e., deflocculation) may be caused by a specific protective stress response in bacteria. Water Environ. Res., 74, 306 (2002).

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Detection of GroEL in activated sludge: a model for detection of system stress

Cited by 16 publications

References 24 publications

Physiological responses of Pseudomonas putida to formaldehyde during detoxification

Physiological responses of Pseudomonas putida to formaldehyde during detoxification

Linking genetic identity and function in communities of uncultured bacteria

Investigating a Mechanistic Cause for Activated‐Sludge Deflocculation in Response to Shock Loads of Toxic Electrophilic Chemicals

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