Ectomycorrhizal mycelia reduce bacterial activity in a sandy soil

Abstract: Bacterial activity was studied in a growth system containing Pinus contorta seedlings inoculated with different mycorrhizal fungi. Nylon nets enabled separation of soil compartments with extramatrical mycorrhizal hyphae from soil compartments with roots and mycelium. In three separate experiments bacterial activity, estimated as thymidine incorporation, was reduced in soils with Paxillus involutus hyphae compared to controls without mycorrhizal hyphae. This effect was found irrespective of compartments with and without roots were compared. Laccaria bicolor only reduced the activity in one of these three experiments. Thelephora terrestris (tested in two experiments), Laccaria proxima, Suillus variegatus and Hebeloma crustuliniforme (one experiment), also reduced the thymidine and leucine incorporation rates of bacteria. The reduction for these fungi varied between 20% and 50% in all experiments. Numbers of viable bacteria appeared to be reduced by T. terrestris, L. proxima, S. variegatus and H. crustuliniforme in one experiment, while no effect was seen in the other experiments.     

Purpura and dermal thinning associated with high dose inhaled corticosteroids.

OBJECTIVE--To assess the effect of high dose inhaled corticosteroids on skin. DESIGN--Cross sectional study of patients receiving treatment for chest diseases. SETTING--Outpatient chest clinic in a teaching hospital. PATIENTS--68 Patients divided into four groups of similar age--namely, 15 receiving long term oral prednisolone, 21 receiving high dose inhaled corticosteroids, 15 receiving low dose inhaled corticosteroids, and 17 controls. MAIN OUTCOME MEASURES--Skin thickness at three sites measured by A scan ultrasound and clinical assessment of purpura. RESULTS--Compared with controls patients in both the oral prednisolone treated group and the high dose inhaled corticosteroid treated group had significantly thinner skin at all three sites (group median thicknesses: prednisolone treated group 28-33% less than controls; high dose inhaled corticosteroid treated group 15-19% less than controls). Differences in skin thicknesses between the low dose inhaled corticosteroid treated group and the controls were trivial. The prevalence of purpura was significantly greater in patients receiving oral prednisolone (12/15 patients) and high dose inhaled corticosteroids (10/21) than in controls (2/17). CONCLUSION--Skin thinning and purpura represent further evidence of systemic effects of high dose inhaled corticosteroids.