Purification and characterization of pentobarbital-induced cytochrome P-450BM-1 from Bacillus megaterium ATCC 14581

When Bacillus megaterium ATCC 14581 is grown in the presence of barbiturates, a cytochrome P-450-dependent fatty acid monooxygenase (Mr 120000) is induced (Kim, B.-H. and Fulco, A.J. (1983) Biochem. Biophys. Res. Commun. 116, 843-850). Gel filtration chromatography of a crude monooxygenase preparation from pentobarbital-induced B. megaterium indicated that not all of the induced cytochrome P-450 present in the extract was accounted for by this high-molecular-weight component. Further purification revealed the presence of two additional but smaller cytochrome P-450 species. The minor component, designated cytochrome P-450BM-2, had a molecular mass of about 46 kDa, but has not yet been completely purified or further characterized. The major component, designated cytochrome P-450BM-1, was obtained in pure form, exhibited fatty acid monooxygenase activity in the presence of iodosylbenzenediacetate, and has been extensively characterized. Its Mr of 38000 makes it the smallest cytochrome P-450 yet purified to homogeneity. Although it is a soluble protein, a complete amino acid analysis indicated that it contains 42% hydrophobic residues. By the dansyl chloride procedure the NH2-terminal amino acid is proline; the penultimate NH2-terminal residue is alanine. The absolute absorption spectra of cytochrome P-450BM-1 show maxima in the same general regions as do P-450 cytochromes from mammalian or other bacterial sources, but they differ in detail. The oxidized form of P-450BM-1 has absorption maxima at 414, 533 and 567 nm, while the reduced form has peaks at 410 and 540 nm. The absorption maxima for the CO-reduced form of P-450BM-1 are found at 415, 448 and 550 nm. Antisera from rabbits immunized with pure P-450BM-1 strongly reacted with and precipitated this P-450, but showed no detectable affinity for either the 46 kDa P-450 or the 120 kDa fatty acid monooxygenase.     

Changes in activity of enzymes metabolizing glucose 6-phosphate during development of the basidiomycete Schizophyllum

During the formation of fruit bodies in the basidiomycete Schizophyllum commune, there are changes in the specific activities of the enzymes utilizing glucose 6-phosphate. These include a 50% increase in the relative amount of glucose-6-phosphate dehydrogenase followed by a decrease in this enzyme and a 90% decrease in phosphoglucomutase activity. This results in a 10-fold change in the relationship between these two enzymes during development. The activities in several mutants were examined and abnormal enzyme levels were found in some cases. The activity of 6-phosphogluconate dehydrogenase was also examined, and its contribution to the assay of the other enzymes was determined.     

Commitment to fruiting in synchronously developing cultures of the basidiomycete Schizophyllum commune

Summary 1. A simple technique is described for obtaining large numbers of localized and synchronized fruit bodies of Schizophyllum commune by lowering the carbon dioxide level in mated cultures. 2. The fruiting process is unaffected by a continuous supply of glucose (0.4–2%). However, synchrony and commitment are lost when the glucose concentration is raised to 4%. 3. Five per cent carbon dioxide inhibits the further development of fruit bodies at all stages except the expansion of the already formed basidiocarp. 4. Fruit bodies can develop at 30°C when a CO₂ trapping agent is employed, contrary to previous reports. 5. A possible relationship between the rate of vegetative growth and the initiation of fruiting is discussed.     

The Implication of Early Chromatin Changes in X Chromosome Inactivation

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Dispersal abilities of riverine freshwater mussels influence metacommunity structure

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An application of a general branching process in the study of the genetics of aging.

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