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Title: Studies on insect immune systems
Author: Tjandra Anggraeni, S.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1991
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Improvements in the purification of Galleria mellonella haemocytes using Percoll gradients are described. This procedure resulted in 95% purity for plasmatocytes, 89% for granular cells and 69% for spherule cells. Using unwashed haemocytes taken directly off the Percoll gradients for making monolayers showed that Ca2+ ion concentration, incubation time and temperature affect the number of cells attaching to the coverslips. The inability of these unwashed cells to undertake phagocytosis is discussed. In contrast, separated and washed haemocytes were highly phagocytic although ingestion was confined to the plasmatocyte cell type. Maximal ingestion by the plasmatocyte was, however, obtained only after the readdition of the granular cells to the plasmatocyte monolayer, illustrating the necessity for cell-cell co-operation in this process. Phenoloxidase activity was also tested in separated cells and it has been confirmed that prophenoloxidase is present in the granular cell type which indicates that this system may be involved in the haemocyte co-operation process. Haemolymph from G. mellonella was tested for the presence of lectins using a range of vertebrate erythrocytes. Only French Press-treated haemolymph with calf and rabbit erythrocytes yielded positive results, however, the levels of haemagglutination were low. Analysis of the physical and chemical properties of G. mellonella lectin showed it to be Ca2+ ion dependent, heat-labile and precipitated by ammonium sulphate. Also, the haemagglutination could be inhibited maximally by lactose and the titre was unchanged in the presence of 2% BSA. G. mellonella lectin was purified via a three-step procedure utilizing ammonium sulphate precipitation, ion exchange chromatography with DEAE Sephadex, and affinity chromatography with Sepharose 4B. One band with an estimated molecular mass of 40 kDa in the lactose fraction is probably the isolated lectin.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available