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Shows that copper-containing methanobactin (Cu-mb) from Methylococcus capsulatus Bath stimulates membrane-associated methane monooxygenase (pMMO) activity. Electron paramagnetic resonance spectra of the pMMO and mb; Suggestion that the stimulation is due to an increased rate of electron flow to the type II Cu(II) centers of the pMMO.

Examines the membrane-associated methane monooxygenase (pMMO) and pMMO-NADH. Nature of the physiological reductant to the pMMO; Effect of detergent concentration on purified pMMO; Detergent/protein ratio.

Investigates the temporal pigmentation changes resulting from the development of a purple color in anaerobic swine waste lagoons. Morphological, physiologenetic characterization of photosynthetic bacterium rhodobacter sp. strain PS9; Capability of rhodobacter to grow on a variety of organic compounds; Correlation of rhodobacter bloom with lagoon water temperature and sulfate and phosphate concentrations.

Characterizes the membrane-associated quinoprotein formaldehyde dehydrogenase from the obligate methylotroph Methylococcus capsulatus. Oxidation of formaldehyde to formate; Proposed pathways of methane oxidation; Extraction of chromopores from the enzyme.

Methanotrophic bacteria catalyze the aerobic oxidation of methane to methanol using Cu-containing enzymes, thereby exerting a modulating influence on the global methane cycle. To facilitate the acquisition of Cu ions, some methanotrophic bacteria secrete small modified peptides known as "methanobactins," which strongly bind Cu and function as an extracellular Cu recruitment relay, analogous to siderophores and Fe. In addition to Cu, methanobactins form complexes with other late transition metals, including the Group 12 transition metals Zn, Cd, and Hg, although the interplay among solution-phase configurations, metal interactions, and the spectroscopic signatures of methanobactin-metal complexes remains ambiguous. In this study, the complexation of Zn, Cd, and Hg by methanobactin from Methylocystis sp. strain SB2 was studied using a combination of absorbance, fluorescence, extended x-ray absorption fine structure (EXAFS) spectroscopy, and time-dependent density functional theory (TD-DFT) calculations. We report changes in sample absorbance and fluorescence spectral dynamics, which occur on a wide range of experimental timescales and characterize a clear stoichiometric complexation dependence. Mercury L3-edge EXAFS and TD-DFT calculations suggest a linear model for Hg S coordination, and TD-DFT suggests a tetrahedral model for Zn2+ and Cd2+. We observed an enhancement in the fluorescence of methanobactin upon interaction with transition metals and propose a mechanism of complexation-hindered isomerization drawing inspiration from the wild-type Green Fluorescent Protein active site. Collectively, our results represent the first combined computational and experimental spectroscopy study of methanobactins and shed new light on molecular interactions and dynamics that characterize complexes of methanobactins with Group 12 transition metals. The complexation of Group 12 transition metals by methanobactin peptides from Methylocystis sp. strain SB2 is studied using absorbance spectroscopy, fluorescence emission spectroscopy, and electronic structure calculations. Trends in transition metal complexation are reported and a molecular mechanism for a notable fluorescence enhancement with transition metal complexation is proposed. [Display omitted] • Methylocystis sp. strain SB2 methanobactin forms complexes with Group 12 transition metals. • Absorbance and fluorescence spectra change with methanobactin-metal stoichiometry and time. • Hg L3-edge extended x-ray absorption fine structure suggests linear Hg—S coordination. • Computational results suggest Hg2+-methanobactin coordination differs from Zn2+ and Cd2+ • Fluorescence enhancement observed suggests complexation-hindered isomerization mechanism. [ABSTRACT FROM AUTHOR]

Methylomicrobium strains are widespread in saline environments. Here, we report the complete genome sequence of Methylomicrobium alcaliphilum 20Z, a haloalkaliphilic methanotrophic bacterium, which will provide the basis for detailed characterization of the core pathways of both single-carbon metabolism and responses to osmotic and high-pH stresses. Final assembly of the genome sequence revealed that this bacterium contains a 128-kb plasmid, making M. alcaliphilum 20Z the first methanotrophic bacterium of known genome sequence for which a plasmid has been reported. [ABSTRACT FROM AUTHOR]

Methylosinus trichosporium OB3b (for "oddball" strain 3b) is an obligate aerobic methane-oxidizing alpha-proteobacterium that was originally isolated in 1970 by Roger Whittenbury and colleagues. This strain has since been used extensively to elucidate the structure and function of several key enzymes of methane oxidation, including both particulate and soluble methane monooxygenase (sMMO) and the extracellular copper chelator methanobactin. In particular, the catalytic properties of soluble methane monooxygenase from M. trichosporium OB3b have been well characterized in context with biodegradation of recalcitrant hydrocarbons, such as trichloroethylene. The sequence of the M. trichosporium OB3b genome is the first reported from a member of the Methylocystaceae family in the order Rhizobiales. [ABSTRACT FROM AUTHOR]

The article offers information on the chemical structure of Methanobactin (mb), a copper binding peptide produced by methanotrophic bacteria, through mass spectrometry and Nuclear Magnetic Resonance. It says that mb uses methane as their primary source of energy and that mb can be found within the bacterial cells and associated with the copper and iron containing particulate methane mono-oxygenase enzyme (pMMO). Moreover, it can be isolated from the growth media of methanotrophs.

Direct multicomponent analysis of malodorous volatile organic compounds (VOCs) present in ambient air samples from 29 swine (Sus scrofa) production facilities was used to develop a 19-component artificial swine odor solution that simulated olfactory properties of swine effluent. Analyses employing either a human panel consisting of 14 subjects or gas chromatography were performed on the air stream from an emission chamber to assess human olfactory responses or odorant concentration, respectively. Analysis of the olfactory responses using Fisher's LSD statistics showed that the subjects were sensitive to changes in air concentration of the VOC standard across dilutions differing by approximately 16%. The effect of chemical synergisms and antagonisms on human olfactory response magnitudes was assessed by altering the individual concentration of nine compounds in artificial swine odor over a twofold concentration range while maintaining the other 18 components at a constant concentration. A synergistic olfactory response was observed when the air concentration of acetic acid was increased relative to the concentration of other VOC odorants in the standard. An antagonistic olfactory response was observed when the air concentration of 4-ethyl phenol was increased relative to the other VOC odorants in the standard. The collective odorant responses for nine major VOCs associated with swine odor were used to develop an olfactory prediction model to estimate human odor response magnitudes to swine manure odorants through measured air concentrations of indicator VOCs. The results of this study show that direct multicomponent analysis of VOCs emitted from swine effluent can be applied toward estimating perceived odor intensity.

Gaseous emissions from swine (Sus scrofa) manure storage systems represent a concern to air quality due to the potential effects of hydrogen sulfide, ammonia, methane, and volatile organic compounds on environmental quality and human health. The lack of knowledge concerning functional aspects of swine manure management systems has been a major obstacle in the development and optimization of emission abatement technologies for these point sources. In this study, a classification system based on gas emission characteristics and effluent concentrations of total phosphorus (P) and total sulfur (S) was devised and tested on 29 swine manure management systems in Iowa, Oklahoma, and North Carolina in an effort to elucidate functional characteristics of these systems. Four swine manure management system classes were identified that differed in effluent concentrations of P and S, methane (CH4) emission rate, odor intensity, and air concentration of volatile organic compounds (VOCs). Odor intensity and the concentration of VOCs in air emitted from swine manure management systems were strongly correlated (r2 = 0.88). The concentration of VOC in air samples was highest with outdoor swine manure management systems that received a high input of volatile solids (Type 2). These systems were also shown to have the highest odor intensity levels. The emission rate for VOCs and the odor intensity associated with swine manure management systems were inversely correlated with CH4 and ammonia (NH3) emission rates. The emission rates of CH4, NH3, and VOCs were found to be dependent upon manure loading rate and were indirectly influenced by animal numbers.