BLOOD COAGULATION IN ARTHROPODS. III. REACTIONS OF INSECT HEMOLYMPH TO COAGULATION INHIBITORS OF VERTEBRATE BLOOD

Open Access
Publisher Website
Google Scholar
Abstract
1. The effects of 33 substances, most of them anticoagulants of vertebrate blood, have been investigated in vitro on the hemolymph of different species of insects, chiefly Orthoptera, exhibiting in normal conditions a conspicuous process of coagulation. 2. The tests (900 approximately) consisted of mixtures in equal amounts of hemolymph and solutions at various concentrations in a special Ringer for insects (Meisenheimer's fluid) of the substances studied. The mixtures were observed by means of a phase contrast microscope after they were spread out in thin films between slide and coverglass. 3. The part played in the reactions by the dilution of the hemolymph and by the pH of the solutions used was appreciated in control preparations made with Meisenheimer's fluid alone at various pH values; no interference with the coagulation process was recorded within the range of pH used (0.60 to 9.45). 4. The morphological criterion selected for appreciating an anticoagulant effect was the development or the absence of alterations in the category of hemocytes especially involved in the initiation of the plasma coagulation, and the development or the absence of coagulation islands around these cells. 5. From the 33 substances tested, 18 were efficient anticoagulants in relatively small amounts; among them were four salts, removers of calcium ions or de-ionizing agents of vertebrate blood, six organic esters of sulfuric acid, including trypanocidal drugs, two basic dyes and three reducing substances. Consistent anticoagulant effects could not be obtained with heparin, and with solutions of the following substances (unless at high concentrations and, for some of them, after acidification or alkalinization): diethylamine, cysteine hydrochloride, glutathione, 1-ascorbic acid, peptone, Apikur and hexamethylene glycol. 6. Different hydrophobic surfaces, including glass coated with Silicone G. E. Drifilm No. 9987, did not induce any definite modification in the coagulation process. 7. A tentative explanation of the anticoagulant effects is given in the discussion; when the substances tested prevent the morphological alterations in the category of hyaline hemocytes involved in the process of coagulation, this process does not occur. The results bring additional support to the previous interpretation that the hyaline hemocytes play an important part in the initiation of the hemolymph coagulation in different insects.