A novel dialysis fermentor design and its application to the production of a cytotoxin fromPasteurella haemolytica

Summary A multi-compartment dialysis membrane fermentor, with a combined compartment volume of one liter, was designed with vertical dialysis bag placement and individual bag inoculation ports. These ports, based on an adaptation of standard Swagelok^R bulkhead type stainless steel fittings, allowed sterile access to each bag lumen during growth. This design has been used extensively to study the growth characteristics and secreted macromolecular products fromPasteurella haemolytica cultures isolated from bovine lung infected with shipping fever pneumonia.     

Influence of subantarctic Macrocystis bed metabolism in diel changes of marine bacterioplankton and CO2 fluxes

The significance of bacterial communities in the fluxes of carbonand energy in giant kelp beds (Macrocystis pyrifera) in KerguelenArchipelago, subantarctica, was estimated by measuring bacterioplanktonbiomass and production over diel cycles in surface seawaterslocated inside and outside of Macrocystis beds. Several physicochemicalparameters [temperature, solar radiation, tide level, dissolvedoxygen, total inorganic carbon (TCO₂), partial pressure of CO₂(pCO₂) and dissolved organic carbon (DOC)] were simultaneouslyrecorded in order to establish possible relationships with observedchanges in bacterial parameters. Bacterial biomass and productionwere significantly higher inside the kelp bed than in the surroundingarea. Furthermore, the results showed large and clear diel variationsof all parameters measured inside the kelp bed. Changes in dissolvedoxygen, TCO₂ and pCO₂ paralleled those of solar radiation, andwere obviously related to the metabolic activity of the kelp.Mean cell volumes and saprophytic bacterial abundance variedover the diel cycles in the same way as photosynthetic activity,while DOC, bacterioplankton production and the frequency ofdividing cells varied in an opposite way with maximal valuesat night-time.