4-Oxalomesaconate hydratase from Pseudomonas ochraceae NGJ1 is unstable in the absence of reducing reagents such as dithiothreitol, and strongly inhibited by 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB). To study the role of cysteine residues in enzyme catalysis, the eight individual cysteine residues of the enzyme were replaced with serine residues by site-directed mutagenesis. The catalytic properties and chemical modification of wild- and mutant type-enzymes by DTNB showed that (i) none of eight cysteine residues was essential for enzyme catalysis; (ii) the inhibition by DTNB was mostly due to modification of Cys-186; (iii) Cys-96 might be another residue reacting with DTNB, and its modification caused an increase in the K(m)-value for 4-oxalomesaconate; (iv) the other six cysteine residues were inaccessible to DTNB, but susceptible to HgCl(2); and (v) only replacement of Cys-186 remarkably improved the stability of the enzyme in the absence of reducing reagent.

The electrical resistivity of the oceanic crust is sensitive to the porosity of the crust and the fluid temperature within crustal fractures and pores. The spatial variation of the crustal porosity and the fluid temperature that is related to a hydrothermal circulation can be deduced by revealing an electrical resistivity structure of the oceanic crust involving a hydrothermal site. We carried out a magnetometric resistivity experiment using an active source to reveal an electrical resistivity structure of the oceanic crust at the Snail site on the ridge crest of the Southern Mariana Trough. Active source electric currents were transmitted along and across the ridge axis in a 4,000 m 2 area including the Snail site. Five ocean bottom magnetometers were deployed around the Snail site as receivers to measure the magnetic field induced by the transmission of the active source electric currents. The amplitude of the induced magnetic field was calculated by maximizing data density and the signal to error ratio in the data, and locations of the transmissions were determined using several types of calibration data. An optimal 1-D resistivity structure of the oceanic crust, averaged over the experimental area, was deduced by least squares from the data of the amplitude of the magnetic field and the location of the transmission. After calculating magnetic field anomalies, which are deviations of the observed amplitude from the prediction of the optimal 1-D resistivity model, an optimal 3-D resistivity structure was deduced from the magnetic field anomalies through trial and error 3-D forward modeling. The optimal 1-D resistivity structure is a two-layer model, which consists of a 5.6 Ω-m upper layer having a 1,500 m thickness and a 0.1 Ω-m underlying half-space. Using Archie's law and porosity profiles of the oceanic crust, the resistivity of 5.6 Ω-m at depths ranging from 800 to 1,500 m suggests the presence of hightemperature fluid related to the hydrothermal circulation. The resistivity of 0.1 Ω-m below 1,500 m depth may represent a magma mush that is a heat source for the hydrothermal circulation. The optimal 3-D resistivity structure includes a conductive anomaly (0.56 Ω-m in approximately 300 m 2 area down to 400 m depth) immediately below the Snail site, two resistive anomalies (56 Ω-m with slightly larger volumes than the conductive anomaly) adjacent to the conductive anomaly on the across-ridge side, and three conductive anomalies away from the Snail site. The conductive anomaly immediately below the Snail site suggests hydrothermal fluid, and the adjacent resistive anomalies suggest areas of low porosity. The size and distribution of the conductive and resistive anomalies near the Snail site constrains the size and style of the hydrothermal circulation.

The mushroom bed cultivation of wood-decaying edible mushrooms generates a large amount of waste mushroom beds, composed of decayed woods. The analysis of the waste mushroom beds after shiitake （Lentinus edodes） mushrooms cultivation showed that cellulose content was 25.4％, which was one of the main components. In this study, we applied TEMPO （2,2,6,6-tetramethylpiperidine-1-oxyl radical） -mediated oxidation to the waste mushroom beds of shiitake, and cellulose nanofibers were prepared. The waste mushroom beds （1.0 g） were treated with catalytic amount of TEMPO and sodium bromide under three conditions of NaClO, 20, 40 and 80 mmol. After this TEMPO-mediated oxidations, water-insoluble fractions were suspended in water, and disintegrated to individual cellulose nanofibers by sonication. When observed by the transmission electron microscopy （TEM） , these nanofibers had widths of 2-3 nm and lengths of several microns. Dry films prepared by casting of the obtained nanofiber dispersions were transparent. The highest yield of the film was obtained at the condition of 80 mmol NaClO, which was 0.18 g per 1.0 g of the waste mushroom bed （71％ toward cellulose content in the waste mushroom bed） .