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Genetic, biochemical and morphological analysis of flagella formation in gram-negative bacteria, Escherichia coli and Salmonella typhimurium, established an outline of the mechanism of stepwise biogenesis of flagella.1>2) The basal body is joined with the cell surface through several rings.3) In gram-positive bacteria, two ringlike structures also exist.3) The inner ring appears to be in contact with the plasma membrane and the outer ring may be associated with the teichoic acid polymers on the outer surface of the cell.2) Non-flagellate mutants of grampositive bacteria have not been so intensively studied in contrast to gram-negative bacteria. However, Kunst et al.,A) Sekiguchi et al.5) and Ayusawa et al.6) described pleiotropic mutants of Bacillus subtilis, almost all of which were non-motile. All of these mutants seem to be defective in the same unknown component of the cell surface,7) which results in pleiotropic changes such as overproduction of a-amylase and exocellular proteases, and inability of flagella formation. The pap mutant, moreover, was not transformable.8) During the course of studies on isolation and characterization of carbohydrate metabolism mutants of Bacillus, it was found that the transketolase mutation (tkt) in B. subtilis IFO 12114 generated pleiotropic changes; the

A new enzymatic acyloin-type condensation between pyruvate (or acetoin or methylacetoin) and o-glyceraldehyde was found to be catalyzed by cell-free extracts of a transketolase mutant of Bacillus pumilus IFO 12089. The reaction product (1) was isolated and determined to be 1-deoxy-othreo-pentu1ose (o-DTP), which is considered to be a precursor of the five-carbon unit of the thiazole ring thiamine. 1-DeoxY-L-threo-pentulose (L-DTP, 2) was synthesized similarly when Lglyceraldehyde was used instead of o-glyceraldehyde. The configurations of 1 and 2 were confirmed by reduction to the corresponding 1-deoxy-pentitols. Similar enzyme activities were also detected in cell-free extracts of all the wild-type strains tested of bacteria, actinomycetes, yeasts, and molds. These results suggest that the o-DTP synthesizing enzyme plays an important role in the biosynthesis of the thiazole ring of thiamine in vivo.

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Cell-free extracts of Bacillus subtilis contain enzymeactivities whichcatalyze an acyloin-type condensation reaction (carboligase reaction) resulting in the formation of 1-deoxy-ketoses. The