Two species of Vesicular-Arbuscular Mycorrhizal (VAM) fungi, Glonnis intraradices and Glomus mosseae, were evaluated in a 2 year field experiment and a greenhouse experiment, for their effects on growth and nutrient uptake of Ottawa 3 apple rootstock in soil infested with the root-lesion nematode, Pratylenchus penetrans. Plants were inoculated with one of the two species of VAM fungi prior to planting into fumigated and non-fumigated field plots. Non-fumigated plots were naturally infested with the nematode and fumigated plots were re-infested with the nematode at the time of transplanting. The abundance of vesicles and arbuscules was greater in roots of plants inoculated with VAM fungi than in roots of non-inoculated plants, even in non-fumigated plots where roots were colonized by native VAM fungi. Inoculation with VAM fungi increased plant growth and leaf concentrations of P, Cu, Mg, and Zn in fumigated plots but not in non-fumigated plots, indicating that colonization by the native VAM fungi in non-fumigated plots may have been sufficient for adequate nutrient acquisition. Inoculation with VAM fungi reduced populations of P. penetrans in roots and soil from the root zone. The effect of VAM fungi on nematode populations was most pronounced in fumigated soil, indicating that nematode suppression may contribute to the improved plant growth and nutrient uptake observed for VAM-inoculated plants in fumigated soil. In greenhouse studies, colonization of apple roots by VAM fungi was reduced by P. penetrans.

The interaction of Pseudomonas chlororaphis strain Sm3 and the root-lesion nematode Pratylenchus penetrans was investigated in three separate greenhouse experiments with soils from southern British Columbia, Canada. The bacteria were applied to the roots of strawberry plants and planted in unpasteurized field soils, with natural or supplemented infestation of P. penetrans. Nematode suppression in roots was evident after 6 or 10 weeks in all experiments. Root or shoot growth were increased after 10 weeks in two experiments. Population dynamics of P. chlororaphis Sm3 in the rhizosphere was followed using an antibiotic-resistant mutant of P. chlororaphis Sm3. There was no apparent correlation between bacterial density in the rhizosphere and P. penetrans suppression in strawberry roots and rhizosphere soil, although the soil with the highest nematode reduction also had the largest P. chlororaphis Sm3 population in the rhizosphere.

Treatment of potato tubers with the plant-health-promoting rhizobacterium A. radiobacter (G 12) resulted in significant (P less than or equal to 0.05) reductions in G. pallida penetration (25 %) in green-house studies conducted in a non-sterilized sandy-loam soil. Significant reductions (P less than or equal to 0.05) in nematode infection were obtained when soil moisture was maintained between 60 and 90 % of field capacity. When moisture levels were held at 30 % of field capacity, nematode infection was also reduced, but not significantly. A. radiobacter repeatedly reduced nematode root-infection levels but did not affect the final population density. A. radiobacter reduced the hatch of G, pallida significantly (P less than or equal to 0.01) in vitro up to 70 %. The bacterium effectively reduced nematode hatch at both 20 and 25 degrees C.

Two soils of an experimental station in the Rhine valley near Bonn, cultivated according to IFOAM guidelines, were analyzed for several soil microbiological parameters during a period of 3 years. Analyses included biomass, dehydrogenase, catalase and the four exo-enzymes protease, alkaline phosphatase, sucrase, and beta-glucosidase. Microbial biomass proved to be a useful parameter to observe status and developments of sustainable soil productivity, as well as dehydrogenase and catalase. Exo-enzymes were not well correlated to biomass but they were useful in monitoring specific nutrient cycles.

On immunoprecipitation using a specific antiphosphotyrosine antibody, phosphatidylinositol kinase (EC 2.7.1.67) activity was separated from the protein-tyrosine kinase (EC 2.7.1.112) activity of the wheat germ agglutinin (WGA)-purified insulin receptor from human placenta. This clearly indicates that protein-tyrosine kinase and phosphatidylinositol kinase activity do not reside on the same polypeptide chain as previously has been suggested. Quantitatively, the fraction of phosphatidylinositol kinase that was bound to WGA sepharose and eluted together with the insulin receptor amounted to 2% of the Triton X-100 soluble phosphatidylinositol kinase. The apparent Km values of the bound and unbound phosphatidylinositol kinase with respect to PI and ATP were very similar (0.4 and 0.3 mmol/1 and 8 and 7 μmol/1, respectively) suggesting that the WGA-bound phosphatidylinositol kinase is not a different enzyme, but rather represents a small portion of the bulk Triton X-100-soluble phosphatidylinositol kinase that is bound to the lectin tightly associated with the insulin receptor. The synthetic polymer (Glu80Tyr20)n, a model substrate of the insulin receptor tyrosine kinase, at 0.5 mmol/1, inhibited phosphatidylinositol kinase of WGA-purified insulin receptor by 70–90%. This inhibition was not overcome by increasing the concentrations of ATP or PI as one would expect if a functional interrelationship of the protein-tyrosine kinase and the phosphatidylinositol kinase would exist.