Purification of three catalase isozymes from facultatively alkaliphilic Bacillus firmus OF4

AbstractCell extracts of facultatively alkaliphilic B. firmus OF4 were assayed for catalase activity and their catalase isozyme content was analyzed on native polyacrylamide gels stained for catalase activity. pH-10.5-grown cells had about twice the specific catalase activity of pH-7.5-grown cells. The higher activity, however, did not confer resistance to exogenous hydrogen peroxide challenge relative to pH-7.5-grown cells and, in fact, the pH-10.5-grown cells were much more sensitive to the challenge. Electrophoresis resolved three catalase isozymes in cell extracts. The isozymes, labeled I–III in order of decreasing electrophoretic mobility, were purified and their Nterminal amino acid sequences were obtained. Isozyme III corresponded to the product of a cloned gene fragment that had been shown to possess substantial sequence similarity to the KatE (HP-II) catalase of E. coli (Quirk, P.G., Krulwich, T.A. and Hicks, D.B. (1993) Biophys. J. 64, 164A) and which had similar biochemical properties to HP-II, i.e., it was a chlorin-containing enzyme expressed only in stationary phase. Isozyme II, a protoheme enzyme, was responsible for the higher activity of alkaline-grown cells and was induced in cells treated with hydrogen peroxide or ascorbate. It showed sequence similarity to katA of Bacillus subtilis (Bol, D. and Yasbin, R. (1991) Gene 109, 31–37). Isozyme I was the only isozyme that exhibited detectable levels of peroxidase activity in addition to catalase activity, resembling a catalase enzyme purified from a different alkaliphile, Bacillus YN-2000 (Yumoto, I., Fukumori, Y. and Yamanaka, T. (1990) J. Biochem. 108, 583–587), to which it showed some sequence similarity

AN INTRODUCTION TO THE NMFS MARINE RECREATIONAL FISHERIES STATISTICS SURVEY WITH AN EMPHASIS ON ECONOMIC VALUATION

Resource /Energy Economics and Policy,

A z=0.9 supercluster of X-ray luminous, optically-selected, massive galaxy clusters

We report the discovery of a compact supercluster structure at z=0.9. The structure comprises three optically-selected clusters, all of which are detected in X-rays and spectroscopically confirmed to lie at the same redshift. The Chandra X-ray temperatures imply individual masses of ~5x10^14 Msun. The X-ray masses are consistent with those inferred from optical--X-ray scaling relations established at lower redshift. A strongly-lensed z~4 Lyman break galaxy behind one of the clusters allows a strong-lensing mass to be estimated for this cluster, which is in good agreement with the X-ray measurement. Optical spectroscopy of this cluster gives a dynamical mass in good agreement with the other independent mass estimates. The three components of the RCS2319+00 supercluster are separated from their nearest neighbor by a mere <3 Mpc in the plane of the sky and likely <10 Mpc along the line-of-sight, and we interpret this structure as the high-redshift antecedent of massive (~10^15 Msun) z~0.5 clusters such as MS0451.5-0305.Comment: ApJ Letters accepted. 5 pages in emulateapj, 3 figure

Cyanobacterial and chloroplast F1-ATPases: cross-reconstitution of photophosphorylation and subunit immunological relationships

The photosynthetic F1-ATPase from the cyanobacterium Spirulina platensis was recently purified in a five-subunit, reconstitutively active form (Hicks, D.B. and Yocum, C.F. (1986) Arch. Biochem. Biophys. 245, 220-229). Here we report on the similarities of the cyanobacterial F1 to the higher plant chloroplast F1 (CF1), as judged by two distinct methods. The ability of each coupling factor to reconstitute photophosphorylation in photosynthetic membranes depleted of F1 content by 2 M NaBr treatment was tested. Addition of either the homologous enzyme (e.g., Spirulina F1, Spirulina membranes) or the heterologous enzyme (e.g., spinach CF1 Spirulina membranes) to depleted membranes increased the rate of phenazine methosulfate-dependent cyclic photophosphorylation from nearly zero to up to 70 [mu]mol ATP/h per mg Chl. Antibodies against four subunits of CF1 ([alpha], [gamma], [delta] and [var epsilon]) and against [beta] of Escherichia coli F1 were reacted with the Spirulina enzyme by protein blotting. The [alpha], [beta] and [gamma] subunits of Spirulina F1 cross-reacted with antibodies against the corresponding subunits from spinach. The cross-reactivity of the [gamma] subunit correlated with previous observations that Spirulina membrane ATPase activity can be modulated by light and dithiothreitol, in a similar fashion to their effect on the enzyme from spinach chloroplasts. The ability of cyanobacterial and chloroplast enzymes to restore activity to heterologous membranes in the absence of immunological similarities between their respective [delta] and [var epsilon] subunits may suggest that structural features other than particular amino acid sequences of these subunits are paramount in their roles in binding F1 to the membrane and in sealing proton leaks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26048/1/0000121.pd

The Partisan Politics of New Social Risks in Advanced Postindustrial Democracies: Social Protection for Labor Market Outsiders

Advanced postindustrialization generates numerous challenges for the European social model. Central among these challenges is declining income, unstable employment, and inadequate training of semi- and unskilled workers. In this chapter, I assess the partisan basis of support for social policies that address the needs of these marginalized workers. I specifically consider the impacts of postindustrial cleavages among core constituencies of social democratic parties on the capacity of these parties to pursue inclusive social policies. I argue – and find support for in empirical analyses – that encompassing labor organization is the most important factor in strengthening the ability of left parties to build successful coalitions in support of outsider-friendly policies. I go beyond existing work on the topic by considering the full array of postindustrial cleavages facing left parties, by more fully elaborating why encompassing labor organization is crucial, and by considering a more complete set of measures of outsider policies than extant work. I compare my arguments and findings to important new work that stresses coalition building and partisan politics but minimizes the role of class organization

Sunyaev Zel'dovich Effect Observations of Strong Lensing Galaxy Clusters: Probing the Over-Concentration Problem

We have measured the Sunyaev Zel'dovich (SZ) effect for a sample of ten strong lensing selected galaxy clusters using the Sunyaev Zel'dovich Array (SZA). The SZA is sensitive to structures on spatial scales of a few arcminutes, while the strong lensing mass modeling constrains the mass at small scales (typically < 30"). Combining the two provides information about the projected concentrations of the strong lensing clusters. The Einstein radii we measure are twice as large as expected given the masses inferred from SZ scaling relations. A Monte Carlo simulation indicates that a sample randomly drawn from the expected distribution would have a larger median Einstein radius than the observed clusters about 3% of the time. The implied overconcentration has been noted in previous studies with smaller samples of lensing clusters. It persists for this sample, with the caveat that this could result from a systematic effect such as if the gas fractions of the strong lensing clusters are substantially below what is expected.Comment: submitte

Synthesis and structural characterization of a mimetic membrane-anchored prion protein

During pathogenesis of transmissible spongiform encephalopathies (TSEs) an abnormal form (PrPSc) of the host encoded prion protein (PrPC) accumulates in insoluble fibrils and plaques. The two forms of PrP appear to have identical covalent structures, but differ in secondary and tertiary structure. Both PrPC and PrPSc have glycosylphospatidylinositol (GPI) anchors through which the protein is tethered to cell membranes. Membrane attachment has been suggested to play a role in the conversion of PrPC to PrPSc, but the majority of in vitro studies of the function, structure, folding and stability of PrP use recombinant protein lacking the GPI anchor. In order to study the effects of membranes on the structure of PrP, we synthesized a GPI anchor mimetic (GPIm), which we have covalently coupled to a genetically engineered cysteine residue at the C-terminus of recombinant PrP. The lipid anchor places the protein at the same distance from the membrane as does the naturally occurring GPI anchor. We demonstrate that PrP coupled to GPIm (PrP-GPIm) inserts into model lipid membranes and that structural information can be obtained from this membrane-anchored PrP. We show that the structure of PrP-GPIm reconstituted in phosphatidylcholine and raft membranes resembles that of PrP, without a GPI anchor, in solution. The results provide experimental evidence in support of previous suggestions that NMR structures of soluble, anchor-free forms of PrP represent the structure of cellular, membrane-anchored PrP. The availability of a lipid-anchored construct of PrP provides a unique model to investigate the effects of different lipid environments on the structure and conversion mechanisms of PrP

Bowen Ratio Energy Balance Measurement of Carbon Dioxide (CO2) Fluxes of No-Till and Conventional Tillage Agriculture in Lesotho

Global food demand requires that soils be used intensively for agriculture, but how these soils are managed greatly impacts soil fluxes of carbon dioxide (CO2). Soil management practices can cause carbon to be either sequestered or emitted, with corresponding uncertain influence on atmospheric CO2 concentrations. The situation is further complicated by the lack of CO2 flux measurements for African subsistence farms. For widespread application in remote areas, a simple experimental methodology is desired. As a first step, the present study investigated the use of Bowen Ratio Energy Balance (BREB) instrumentation to measure the energy balance and CO2 fluxes of two contrasting crop management systems, till and no-till, in the lowlands within the mountains of Lesotho. Two BREB micrometeorological systems were established on 100-m by 100-m sites, both planted with maize (Zea mays) but under either conventional (plow, disk-disk) or no-till soil mangement systems. The results demonstrate that with careful maintenance of the instruments by appropriately trained local personnel, the BREB approach offers substantial benefits in measuring real time changes in agroecosystem CO2 flux. The periods where the two treatments could be compared indicated greater CO2 sequestration over the no-till treatments during both the growing and non-growing seasons