Determination of protease activity of plant roots

The colorimetric method described by Charney and Tomarelli (1974) for the assay of the proteolytic activity in the duodenal juice was adapted to measuring protease activity of roots. Diazotized casein served as substrate and the amount of degraded azocasein was measured colorimetrically. A linear relationship between the incubation time or concentration of the enzyme (roots) and the amount of the hydrolyzed substrate was found. The rate increase of the enzyme reaction was proportional to enzyme concentration up to 1 g roots and incubation time of 3 h, and up to 0.5 g of roots and incubation time of 4 h. The optimum of the protease activity was at pH 8.2–8.6.     

Decomposition of root exudates in soil

The conversion of synthetic root exudates, i.e. of a mixture of amino acids, organic acids and sugars, added to soil in a single dose or continuously, was studied. After the addition of a single dose, the root exudates were gradually mineralized and after 76 hours, 85% of carbon had been released in the form of carbon dioxide. The extent and rate of mineralization was not influenced by the simultaneous addition of ammonium phosphate. The continuous addition of substrate formed a model artificial rhizosphere. In the steady state, 93% of the carbon in the added substrate was mineralized to carbon dioxide. The conversion of organic acids, sugars and amino acids and the mineralization of nitrogen was studied simultaneously by chromatography. In soil continuously enriched with root exudates, phenomena similar to the rhizosphere effect in nature were observed both in the numbers of microorganisms and in the relative incidence of the nutritional groups of bacteria.     

Continuous flow method in soil microbiology

The decomposition of glycine in soil was studied by the continuous flow method. Glycine solution was added continuously to soil samples of different weights, i.e. soil columns of different heights. It was found that the extent of glycine mineralization was related to the weight of the soil. Glycine was nitrified most effectively in the soil sample weighing 30 g., in which 65.8% of the added (91.6% of the retained) glycine nitrogen was oxidized to nitrites and nitrates. No steady state was observed in the rate of nitrite and nitrate formation. The rate of nitrification rose at first, in relation to the weight of the soil, but fell after reaching the maximum. The factor limiting the rate of nitrification was the adsorption of ammonium nitrogen in the soil. By using soil samples of different weights and heights it was found possible to localize the process of ammonia release and the oxidation of ammonia and nitrites in the soil column and to influence the ratio of ammonification and nitrification or of the oxidation of ammonium ions and nitrites.     

A policy management game for mass casualty incidents: an experimental study

The number of complex and unique mass casualty incidents has increased due to natural and technological disasters as well as man-made disasters such as political instabilities, economic recession, and terrorism. Thus, health care policy-makers such as the Austrian Samaritan Organization have been continuously improving the training of emergency staff to enable them to quickly evacuate an emergency site, to minimize the number of fatalities at the incident site, and to decrease the patients’ waiting time for treatment. We developed a policy management game to provide a training tool for emergency staff to support such policy-makers. In addition, with this game students can be educated on scheduling and planning techniques such as simulation, queuing theory, and resource allocation. To investigate the potential of our policy management game, we conducted an experimental study with 96 participants including students, practitioners from health care services, and researchers. They acted as incident commanders to decide on sending medical staff to triage, to different treatment rooms for care and to on-site transportation, as well as to transportation to hospitals during three game runs. The participants rated the general structure and organization of the experiment as high. The performance was also improved by many participants during the experiment. We found differences in performance among the different participant groups.     

Application of simple fed-batch technique to high-level secretory production of insulin precursor using <Emphasis Type="Italic">Pichia pastoris</Emphasis> with subsequent purification and conversion to human insulin

Background  

The prevalence of diabetes is predicted to rise significantly in the coming decades. A recent analysis projects that by the year 2030 there will be ~366 million diabetics around the world, leading to an increased demand for inexpensive insulin to make this life-saving drug also affordable for resource poor countries.