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The membrane-bound formaldehyde dehydrogenase from Methylococcus capsulatus Bath is a homotetramer consisting of 49,500 dalton each subunits. The enzyme oxidizes formaldehyde to formate and uses pyrroloquinoline quinone as its redox cofactor.

Research was conducted to examine the structural gene and polypeptide for high-molecular-mass multi-c-heme cytochromes from Methylococcus capsulatus Bath. Electron paramagnetic resonance spectrum and degenerate oligonucleotide probe were used to prove the presence of multiple low spin and to identify a DNA fragment from M. capsulatus, respectively. Results indicate that cytochrome C5530 and the gene products of ORF3 and ORF1 belong to a novel class of c-type cytochrome.

P460 cytochromes catalyze the oxidation of hydroxylamine to nitrite. A degenerate oligonucleotide probe was synthesized using the N-terminal amino acid sequence of cytochrome P460 and applied in the identification of a DNA fragment from M. capsulatus Bath that contains cyp, the gene encoding cytochrome P460. The overall sequence similarity of the P460 cytochromes from M. capsulatus Bath and N. europaea was low, even though short regions conserved residues are found in both proteins. Both terminals have a C-terminal, c-heme binding motif and a conserved lysine residue.

The gene cycA encoding the tetraheme cytochrome c554 of Nitrosomonas europaea is present in three copies per genome and the cytochrome c554 represents a new class of tetraheme c cytochromes. Southern blot sequence probes reveal that the gene cluster consists of hao, cycA and ORF2 genes and organization of these genes for three proteins results in ammonia oxidation in N. europaea.

The sequence of the entire hao gene cluster that exists as a single copy in the genome of Nitrosococcus oceani and compare it to the hao gene clusters of Nitrosospira multiforms and Nitrosomonas europaea is presented. The analyses of gene cluster organization and phylogenetic analyses of the protein sequences encoded by genes in the hao gene cluster are described.

The properties of a site-specific mutant form of PchF were studied to examine the roles of Arg474 in p-cresol methylhydroxylase (PCMH). The result indicates that these mutant proteins retain all of the basic properties of the corresponding wild-type forms of PchF.

Many studies have identified the potential of rainwater harvesting (RWH) systems to simultaneously augment potable water supply and reduce delivery of uncontrolled stormwater flows to downstream drainage networks. Potentially, such systems could also play a role in the controlled delivery of water to urban streams in ways which mimic baseflows. The performance of RWH systems to achieve these three objectives could be enhanced using Real-Time Control (RTC) technology to receive rainfall forecasts and initiate pre-storm release in real time, although few studies have explored such potential. We used continuous simulation to model the ability of a range of allotment-scale RWH systems to simultaneously deliver: (i) water supply; (ii) stormwater retention; and (iii) baseflow restoration. We compared the performance of RWH systems with RTC technology to conventional RWH systems and also systems designed with a passive baseflow release, rather than the active (RTC) configuration. We found that RWH systems employing RTC technology were generally superior in simultaneously achieving water supply, stormwater retention and baseflow restoration benefits compared with the other types of system tested. The active operation provided by RTC allows the system to perform optimally across a wider range of climatic conditions, but needs to be carefully designed. We conclude that the active release mechanism employing RTC technology exhibits great promise; its ability to provide centralised control and failure detection also opens the possibility of delivering a more reliable rainwater harvesting system, which can be readily adapted to varying climate over both the short and long term. [ABSTRACT FROM AUTHOR]

We examined the bacterial communities in a pool of water under a flowing rock fracture at a depth of 1470 m in the Sanford Underground Research Facility in Lead, SD. High-throughput sequencing of 16S rDNA indicated that Acidobacteria, Chlorobi, Nitrospirae, Planctomycetes, and Gammaproteobacteria (especially Acidiferribacter) were abundant in pool sediments; while Nitrospirae, Plactomycetes, and Proteobacteria (especially Thiobacillus and Methylococcus) were abundant in pool water. Samples of diluted pool water were mixed with agar media, placed in diffusion chambers surrounded by 0.2 µm pore membranes, and incubated in situ within the pool for 19 days. 16S rDNA analysis of media from diffusion chambers indicated Alphaproteobacteria (including Hyphomicrobium), Betaproteobacteria (including Inhella and Methyloversatilis), and Gammaproteobacteria (mainly Pseudomonas) were dominant. Low-nutrient media were used to isolate bacteria from both pool water and media inside diffusion chambers. The majority of these isolates were Methyloversatilis, Inhella, and Bacillus. Although the genera isolated were not very abundant in the pool water, the presence of Methylococcus and Methyloversatilis suggests the importance of methane and methanol oxidation in this community. [ABSTRACT FROM AUTHOR]

Cytochrome c′ of Methylococcus capsulatus Bath is involved in electron flow from the enzyme responsible for hydroxylamine oxidation, cytochrome P460, to cytochrome c555. This cytochrome is spectrally similar to other cytochromes c′ but is larger (16,000 Da) and has a lower midpoint potential (–205 mV). By a combination of Edman degradation, mass spectroscopy, and gene sequencing, we have obtained the primary structure of cytochrome c′ from M. capsulatus Bath. The cytochrome shows low sequence similarity to other cytochromes c′, only residues R12, Y53, G56, and the C-terminal heme-binding region (GXXCXXCHXXXK) being conserved. In contrast, cytochrome c′ from M. capsulatus Bath shows considerable sequence similarity to cytochromes P460 from M. capsulatus Bath (31% identity) and from Nitrosomonas europaea (18% identity). This suggests that P460-type cytochromes may have originated from a c′-type cytochrome which developed a covalent cross-link between a lysine residue and the c′-heme. [ABSTRACT FROM AUTHOR]