Transient gene expression in electroporated protoplasts and intact cells of sugar beet.

Factors influencing the transient expression of introduced foreign DNA in electroporated protoplasts and intact cells of sugar beet were determined by assaying for the activity of chloramphenicol acetyltransferase (CAT), using a rectangular pulse generating system. Extractable CAT activity depended upon 1) applied plasmid DNA concentration, 2) protoplast density, 3) the interaction between pulse field strength, duration, number, time interval between pulses and the resultant effect on culture viability, and 4) the physiological state of the protoplasts. Mesophyll protoplasts were more susceptible to damage by electroporation, and were more specific in their requirement for electroporations which allowed CAT expression, than were protoplasts derived from suspension culture cells.

Manipulation, by nutrient limitation, of the biosynthetic activity of immobilized cells of Capsicum frutescens Mill. cv. annuum.

The relationship between the synthesis and accumulation of protein and capsaicin was investigated in cultured cells of Capsicum frutescens Mill. cv. annuum immobilized in reticulate polyurethane.

The synthetic potential of immobilised cells of Capsicum frutescens Mill cv. annuum.

Cells of Capsicum frutescens Mill. cv. annuum, immobilised in reticulate polyurethane foam, produced higher yields of capsaicin, the pungent principle of Chilli pepper fruits, than did freely-suspended cells, when batch-cultured in a medium conducive to culture growth.

Listeria monocytogens: synergistic effects of ampicillin and gentamicin.

Listeria monocytogenes infections are most common in newborn infants and persons with impaired defense mechanisms. There are reports of successful treatment with ampicillin alone: however, there is uncertainty as to what regimen constitutes the most effective therapy. The purpose of this study was to illustrate the in-vitro synergism between ampicillin and gentamicin against L.