Gerard Jung

Polymer-entrapped rhizobium as an inoculant for legumes

SummaryField and cylinder experiments conducted in France and in Senegal showed that polyacrylamide, previously proposed as an entrapping gel for preparing Rhizobium inoculants, could be replaced by alginate (AER inoculant) or a mixture of xanthan and carob gum (XER inoculant). Semi-dried or dried AER and XER were used successfully provided that their storage time was less than 90 days. In soil inoculation trails, no marked differences were observed among semi-dried XER, dried AER, and dried XER. A number of seed inoculation experiments indicated that dried XER significantly outranked AER. Seeds preinoculated by up to 48 days with XER yielded plants which were comparable in nodulation and growth parameters to those derived from plant receiving peat inoculation at the time of planting.

High-cell density fermentation studies of recombinant Escherichia coli strains expressing human interleukin-1β

Abstract A high-productivity process has been developed for the production of mature human interleukin-1β (IL-1β) from recombinant Escherichia coli strains. Conditions were found that allow high IL-1β expression levels in high cell density cultures. Improved fed-batch fermentation strategies are described which include maintenance of glucose and acetate concentrations below 1 g/l and sparging the fermentor with an O 2 -enriched air supply. Using the E. coli tryptophan promoter control of transcription, a 2.2 g/l production level of IL-1β was achieved in E. coli B at cell densities of 55 g dry weight per litre. Another genetic construction involving the bacteriophage lambda cI ts -P R expression cassette allowed a similar IL-1β production level (1.9 g/l) in E. coli E103S, albeit at a lower cell density (30 g/l). A simplified procedure allowing the purification of fully active IL-1β is also presented.

Alder—Frankia interaction and alder—poplar association for biomass production

Alders have an important role to play in biomass producing stands because of their N2-fixing ability and their capacity to withstand soils having an excess of moisture. The objectives of preliminary trials were (1) to find if there is any alder-genotype × Frankia-strain interaction when the effect of inoculating the bacteria was compared to no inoculation in seed beds of different species and provenances of alder, (2) to measure the possible effect of black alders interplanted in poplars compared to pure poplar plots. Two trials were laid out to study the alder-Frankia interaction. Both produced interaction. In the first one the inoculation had a favorable effect on Alnus glutinosa at age 2 years and A. cordata at age 1 and 2 and no effect on A. rubra. In the second one the inoculation had a depressive effect at age 1 on 2 of 3 provenances of A. rubra and no effect on 1 A. rubra, 3 A. glutinosa and 3 A. cordata provenances.