Recently, use of the cardiolipin (CL)-specific fluorescent dye 10-N-nonyl-acridine orange (NAO) revealed CL-rich domains in the Escherichia coli membrane (E. Mileykovskaya and W. Dowhan, J. Bacteriol. 182:1172-1175, 2000). Staining of Bacillus subtilis cells with NAO showed that there were green fluorescence domains in the septal regions and at the poles. These fluorescence domains were scarcely detectable in exponentially growing cells of the clsA-disrupted mutant lacking detectable CL. In sporulating cells with a wild-type lipid composition, fluorescence domains were observed in the polar septa and on the engulfment and forespore membranes. Both in the clsA-disrupted mutant and in a mutant with disruptions in all three of the paralogous genes (clsA, ywjE, and ywiE) for CL synthase, these domains did not vanish but appeared later, after sporulation initiation. A red shift in the fluorescence due to stacking of two dye molecules and the lipid composition suggested that a small amount of CL was present in sporulating cells of the mutants. Mass spectrometry analyses revealed the presence of CL in these mutant cells. At a later stage during sporulation of the mutants the frequency of heat-resistant cells that could form colonies after heat treatment was lower. The frequency of sporulation of these cells at 24 h after sporulation initiation was 30 to 50% of the frequency of the wild type. These results indicate that CL-rich domains are present in the polar septal membrane and in the engulfment and forespore membranes during the sporulation phase even in a B. subtilis mutant with disruptions in all three paralogous genes, as well as in the membranes of the medial septa and at the poles during the exponential growth phase of wild-type cells. The results further suggest that the CL-rich domains in the polar septal membrane and engulfment and forespore membranes are involved in sporulation.The bacterial cell membrane is widely recognized as a matrix in which lipid molecules are homogeneously distributed. However, it has been noticed that lipid molecules are heterogeneously distributed in bacterial membranes, and the observations increasingly include those obtained by using fluorescent lipophilic probes. Immunoelectron microscopic observations showing the polar localization of the chemoreceptor complexes in Caulobacter crescentus and Escherichia coli cells provided early indications of membrane heterogeneity (1, 27). By using the lipophilic fluorescent styryl dye FM4-64, laterally uneven distribution of the fluorescence, which could be an indication of heterogeneous distribution of phospholipids in E. coli membranes, was then discovered (14). Recently, the cardiolipin (CL)-specific fluorescent dye 10-N-nonyl-acridine orange (NAO) was used to demonstrate that there are CL-containing domains in E. coli membranes, which were observed mostly in the septal regions and at the poles of the cells (31, 32). The hypothesis that there are CL-containing domains in these regions of E. coli cells was supported by an analysis of the li...

The inhibitory effect of ethanol concentration p in a medium on the specific rates of growth μ and ethanol production ν of a specific strain of baker's yeast was studied in a chemostat, where except for ethanol as the product, only the concentration of glucose S was controlled to limit the metabolic activity of the yeast. This was designed to supplement the previous findings from the batch experiment, in which ethanol was added artificially and no substrate components were limiting the metabolism of the same yeast, that μ = μ0e −italick 1italicp and ν = ν0e −italick 1italicp, where k1 and k2 are empirical constants and subscript the 0 denotes respective values at p = 0. The effects of p on the values of μ and ν were confirmed by the Line‐weaver‐Burk plot to belong to noncompetitive inhibition. The formulas here for μ and ν as affected by p, if extrapolated to the case of no limiting substrates, were in good agreement in respective forms with those derived previously from the batch experiment, though the values of corresponding coefficients in these formulas were different. The differential equations for μ and ν as functions of both p and S and, in addition for the rate of glucose consumption as correlated by the yield factors either with the cell growth rate or the rate of ethanol production, were solved properly with a digital computer. A kinetic pattern calculated so far was discussed with reference to the data obtained in the batch experiment and those relevant to actual “sake” brewing.

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Using a three-dimensional compressible magnetohydrodynamic (MHD) simulation, we have reproduced the fast solar wind in a direct and self-consistent manner, based on the wave/turbulence driven scenario. As a natural consequence of Alfvénic perturbations at the coronal base, highly compressional and turbulent fluctuations are generated, leading to heating and acceleration of the solar wind. The analysis of power spectra and structure functions reveals that the turbulence is characterized by its imbalanced (in the sense of outward Alfvénic fluctuations) and anisotropic nature. The density fluctuation originates from the parametric decay instability of outwardly propagating Alfvén waves and plays a significant role in the Alfvén wave reflection that triggers turbulence. Our conclusion is that the fast solar wind is heated and accelerated by compressible MHD turbulence driven by parametric decay instability and resultant Alfvén wave reflection.