Comparative proteomics using 2-D gel electrophoresis and mass spectrometry as tools to dissect stimulons and regulons in bacteria with sequenced or partially sequenced genomes

We propose two-dimensional gel electrophoresis (2-DE) and mass spectrometry to define the protein components of regulons and stimulons in bacteria, including those organisms where genome sequencing is still in progress. The basic 2-DE protocol allows high resolution and reproducibility and enables the direct comparison of hundreds or even thousands of proteins simultaneously. To identify proteins that comprise stimulons and regulons, peptide mass fingerprint (PMF) with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS) analysis is the first option and, if results from this tool are insufficient, complementary data obtained with electrospray ionization tandem-MS (ESI-MS/MS) may permit successful protein identification. ESI-MS/MS and MALDI-TOF-MS provide complementary data sets, and so a more comprehensive coverage of a proteome can be obtained using both techniques with the same sample, especially when few sequenced proteins of a particular organism exist or genome sequencing is still in progress

On the potential for CO₂ mineral storage in continental flood basalts – PHREEQC batch- and 1D diffusion–reaction simulations

<p>Abstract</p> <p>Continental flood basalts (CFB) are considered as potential CO₂ storage sites because of their high reactivity and abundant divalent metal ions that can potentially trap carbon for geological timescales. Moreover, laterally extensive CFB are found in many place in the world within reasonable distances from major CO₂ point emission sources.</p> <p>Based on the mineral and glass composition of the Columbia River Basalt (CRB) we estimated the potential of CFB to store CO₂ in secondary carbonates. We simulated the system using kinetic dependent dissolution of primary basalt-minerals (pyroxene, feldspar and glass) and the local equilibrium assumption for secondary phases (weathering products). The simulations were divided into closed-system batch simulations at a constant CO₂ pressure of 100 bar with sensitivity studies of temperature and reactive surface area, an evaluation of the reactivity of H₂O in scCO₂, and finally 1D reactive diffusion simulations giving reactivity at CO₂ pressures varying from 0 to 100 bar.</p> <p>Although the uncertainty in reactive surface area and corresponding reaction rates are large, we have estimated the potential for CO₂ mineral storage and identified factors that control the maximum extent of carbonation. The simulations showed that formation of carbonates from basalt at 40 C may be limited to the formation of siderite and possibly FeMg carbonates. Calcium was largely consumed by zeolite and oxide instead of forming carbonates. At higher temperatures (60 – 100 C), magnesite is suggested to form together with siderite and ankerite. The maximum potential of CO₂ stored as solid carbonates, if CO₂ is supplied to the reactions unlimited, is shown to depend on the availability of pore space as the hydration and carbonation reactions increase the solid volume and clog the pore space. For systems such as in the scCO₂ phase with limited amount of water, the total carbonation potential is limited by the amount of water present for hydration of basalt.</p