To investigate potential complementary activities of multiple enzymes belonging to the same family within a single microorganism, we chose a set of Old Yellow Enzyme (OYE) homologs of Pseudomonas putida. The physiological function of these enzymes is not well established; however, an activity associated with OYE family members from different microorganisms is their ability to reduce nitroaromatic compounds. Using an in silico approach, we identified six OYE homologs in P. putida KT2440. Each gene was subcloned into an expression vector, and each corresponding gene product was purified to homogeneity prior to in vitro analysis for its catalytic activity against 2,4,6-trinitrotoluene (TNT). One of the enzymes, called XenD, lacked in vitro activity, whereas the other five enzymes demonstrated type I hydride transferase activity and reduced the nitro groups of TNT to hydroxylaminodinitrotoluene derivatives. XenB has the additional ability to reduce the aromatic ring of TNT to produce Meisenheimer complexes, defined as type II hydride transferase activity. The condensations of the primary products of type I and type II hydride transferases react with each other to yield diarylamines and nitrite; the latter can be further reduced to ammonium and serves as a nitrogen source for microorganisms in vivo.
- American Society for Microbiology
- Subfunctionality of hydride transferases of the old yellow ...
Pentachlorophenol degradation by Pseudomonas fluorescens
Fluorescent Pseudomonads strains were considered as plant growth promoting bacteria. They exhibited antagonistic activities against phytopathogens and showed bio-fertilizing properties. The strain Pseudomonas fluorescens PsWw128, isolated from wastewater, can use the pentachlorophenol (PCP) as the sole source of carbon and energy. High-performance liquid chromatography (HPLC) and spectrophotometric methods were used to follow the PCP degradation and biomass PsWw128 formation. However, the removal efficiency of...
Inhibitory effect of thiourea on biological nitrification process and its eliminating method
Thiourea is a typical nitrification inhibitor that shows a strong inhibitory effect against the biological nitrification process. The 50% inhibitory concentration (IC50) of thiourea on nitrification was determined to be 0.088 mg g VSS−1, and nitrifiers recovered from the thiourea inhibition after it was completely degraded. The thiourea-degrading ability of the sludge system was improved to 3.06 mg gVSS−1 h−1 through cultivation of thiourea-degrading bacteria by stepwise increasing the influent thiourea concentrati...
Mortality from selected diseases that can be transmitted by water – United States, 2003–2009
Diseases spread by water are caused by fecal–oral, contact, inhalation, or other routes, resulting in illnesses affecting multiple body systems. We selected 13 pathogens or syndromes implicated in waterborne disease outbreaks or other well-documented waterborne transmission (acute otitis externa, Campylobacter, Cryptosporidium, Escherichia coli (E. coli), free-living ameba, Giardia, Hepatitis A virus, Legionella (Legionnaires' disease), nontuberculous mycobacteria (NTM), Pseudomonas-related pneumonia or septicemia,...
Identification of the bacterial population in manganese removal filters
The aim of this study was to identify bacteria present in ripened manganese removal filters for drinking water production. The bacterial population was identified with ‘next generation’ DNA sequencing, and specific bacteria were quantified with quantitative polymerase chain reaction (qPCR) and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The ‘next generation’ DNA sequencing analysis showed a bacteria population shift from the iron oxidizing...
EPA Proposes Two Test Methods and Guidance for Evaluating Antimicrobial Pesticides
The U.S. Environmental Protection Agency (EPA) has recently announced the availability of two proposed test methods and associated testing guidance for evaluating antimicrobial pesticides against two biofilm bacteria, Pseudomonas aeruginosa and Staphylococcus aureus, for comments. EPA states that registrants of antimicrobial products with public health claims are “required to submit efficacy data to EPA in support of the product’s registration” under the Federal Insecticide, Fungicide, and...