[Cyclic adenosine-3':5'-monophosphate in translocation tissues of plants?]

Sieve tube sap of the secondary phloem of Robinia pesudoacacia L. and exudate from the trumpet hyphae of the cauloids of Laminaria saccharina (L.) Lamour. were analyzed for the occurrence of cyclic adenosine-3':5'-monophosphate with the help of the radio isotope dilution test (Boehringer, Mannheim). The concentration was about 0,1 μM in the Laminaria exudate and 9,0 nM in the Robinia sap. Pretreatment of the saps with phosphodiesterase removes the activity of the A-3:5-MP. It therefore seems probable that A-3:5-MP occurs in the translocation tissues of plants.

[The incorporation of (32)PO 4 (---) into organic compounds in sieve tube sap]

1. Phloem exudates collected from the secondary phloem of Tilia platyphyllos, from the flower stalks of Yucca flaccida and from stems of Salix triandra (obtained by the aphid method) were incubated with (32)PO4 (---). The radioactivity was incorporated into a series of organic compounds very similar to those synthesized after the whole phloem is incubated with (32)PO4 (---). This synthetic ability of the exudate was completely destroyed by heating; therefore it is very probably due to enzymes. 2. ATP is one of the very first compounds labeled after incubation of the sieve tube sap with (32)PO4 (---). It already shows radioactivity after 10 sec. 3. The phloem exudate of Yucca flaccida does not lose the synthetic ability even after several hours of secretion. This indicates that the enzymes and the substrates for the phosphorylations are secreted continuously into the lumen of the sieve tubes. 4. The formation of the organic phosphorus compounds in the sieve tube sap is in accordance with the results of the enzyme analyses in this material (Kennecke et al., 1971).

The euglobulin lysis time test: an ineffectual monitor of the therapeutic inhibition of fibrinolysis

In two clinical situations associated with hyperfibrinolysis the administration of antifibrinolytic drugs resulted in clinical haemostasis. The dilute clot lysis time and fibrin plate activity test but not the euglobulin lysis time reflected this control of excessive fibrinolysis by the antifibrinolytic drugs. The inhibition by epsilon-amino-caproic acid (EACA) of hyperfibrinolysis induced in vitro was reflected by the dilute clot lysis time but not by the euglobulin lysis time. Paper chromatography of the supernatant and euglobulin fractions as prepared for the euglobulin lysis time test from plasma with added EACA demonstrated that some 85% of the EACA was present in the supernatant, normally discarded during the test. Similarly, cellulose-acetate electrophoresis of the supernatant and euglobulin fractions from plasma containing Trasylol demonstrated the drug in the supernatant only. These findings indicate that when acetic acid is added to plasma containing EACA or Trasylol only a small proportion of the drug is precipitated with the euglobulin fraction. The euglobulin lysis time is thus an inaccurate index of the neutralization of hyperfibrinolysis by antifibrinolytic drugs.

[Investigations on ATP and other organic phosphorus compounds in the sieve tube sap of Yucca flaccida and Salix triandra]

1. Like the sieve tube sap of dicotyledons analysed so far, the phloem exudate of Yucca flaccida contains a high level of ATP, i.e. 615 μg/ml on the average. ATP concentration in the phloem exudate does not decrease during extended periods of exudation. 2. The pattern of labelled phosphorylated compounds after feeding of (32)PO 4 (---) is essentially similar in the phloem exudate of Yucca flaccida and in the exudate from the mouth parts of aphids feeding on Salix triandra phloem. 3. The label was incorporated very rapidly into most of the phosphorylated organic compounds present in the exudate of Yucca flaccida. in the first phase after feeding of (32)PO 4 (---) only the label in fructose-1,6-diphosphate and possibly the label in ATP was still increasing in relation to the total radioactivity. This increment was correlated to a loss of radioactivity in the inorganic phosphate fraction. 4. Specific radioactivity of inorganic phosphate and ATP in the sieve tube sap of Yucca flaccida increased continuously throughout the experiments while (32)PO 4 (-) was administered externally. This trend continued for some time after removal of the external source of label.