Soluble trehalase from Panstrongylus megistus Burm.(Reduviidae, Triatominae).
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Biomedical subjects
Publications and source records attributed to L R Marechal.
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The microsomal fraction of insects was found to contain an enzyme which transfers mannose from guanosine diphosphate mannose to an endogenous or exogenous insect lipid and to other acceptors such as dolichol monophosphate or ficaprenol monophosphate. This activity depended on the presence of Triton X-100 and magnesium ions, the optimal concentration of the latter being 10mM. The optimal temperature of the reaction was 25 degrees C and the maximal activity was obtained at pH 7.9. The mannolipid formed behaved as a monophosphodiester when chromatographed on DEAE-cellulose. Weak acid treatment of the product liberated mannose. Its behaviour both on thin layer and Sephadex G-150 chromatography would indicate the presence of a number of isoprenyl units similar to the dolichol and different from the ficaprenol derivative. Stability to phenol treatment indicated that the lipid fraction of the mannolipid is an alpha-saturated polyprenol phosphate similar to dolichol monophosphate.
The antitumor effect of reserve polysaccharide, paramylon, from Euglena gracilis on the transplantable sarcoma-180 was examined in mice. This polysaccharide had an effect similar to that of lentinan. Paramylon, in a dose of 1 mug/g body weight, injected intraperitoneally 24 hr after tumor implantation had an inhibitory effect on the tumor growth, although without causing complete regression of the tumor. Alkaline-treated paramylon had a similar effect but at a smaller concentration than the native one. The inhibitory activity was not lost when the paramylon preparation was treated with pronase, DNase, or RNase. The antitumor effect might be a lymphocyte-mediated process. In tumors that were regressing after treatment, there was extensive outpouring of lymphoid cells with plasma cells and macrophages. A test conducted using paramylon ruled out the possibility of an interferon-mediated inhibiotry effect on tumor growth.