Chiral auxiliary recycling in continuous flow: automated recovery and reuse of Oppolzer's sultam.

The telescoping of a three-stage, chiral auxiliary-mediated transformation in flow is described, including continuous separation of the product and auxiliary. The auxiliary can either be collected for later reuse, or directly fed back to the beginning of the process for recycling in real time, enabling each molecule of auxiliary to make multiple equivalents of chiral product and thus minimizing the step- and atom-economy issues associated with auxiliary-mediated synthesis. This concept is demonstrated for the asymmetric hydrogenation of olefins using Oppolzer's sultam, shortening the total reaction time >100 fold compared to batch, and demonstrating formal sub-stoichiometric auxiliary loading with respect to the process by automating auxiliary recycling within a closed loop.

Surface-disorganized, attenuated mutants of Aeromonas salmonicida as furunculosis live vaccines.

A slow-growing, aminoglycoside-resistant mutant and a rapidly-growing pseudo-revertant were isolated from Aeromonas salmonicida, the causative agent of salmonid furunculosis. These mutants continued to elicit a variety of classical virulence factors associated with A. salmonicida pathogenesis. They differed morphologically from the wild-type and from one another with respect to A-layer organization, membrane antagonist sensitivity and particularly to aerobic metabolism. Both mutants were drastically altered in the architecture of the 2D crystalline surface array (A-layer), although both were similar to wild-type with respect to cell surface composition. The slow-growing, antibiotic-resistant mutant differed significantly from the wild-type by the apparent loss of virtually all aerobic metabolism; the pseudo-revertant had partially recovered the ability to aerobically metabolize certain carbon sources. Both mutants were avirulent and incapable of tissue persistence. The rapidly-growing, antibiotic-sensitive pseudo-revertant, when administered either intraperitoneally or by immersion, effectively protected salmonid fish from challenge by a heterologous virulent stain suggesting its candidature as a live, attenuated furunculosis vaccine.