Lectin Agglutination

1506 words 7 pages
Dwayne Hill.
November 30, 2007
Lab Partner: Sasha-Kaye Graham
Experiment 6 : Lectin Agglutination
To study the agglutination pattern of different strains of Psuedomonas aeruginosa to different sialic acid-binding lectins.
The cell membrane of two strains of Psuedomonas aeruginosa, P22 and P201 were treated the sialic acid lectins SNA I, WGA, MAL and HAA to confirm the presence of sialic acid carbohydrates in the cell surface membranes of these strains. This was done by using two sets of samples-one treated with trypsin and the other without. The sample treated with trypsin showed agglutination for all lectins while the untreated sample showed little to no agglutination. A control was also used with the cells
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Untreated cells
The two strains of P. aeruginosa used for P22 and P201. The level of precipitation for each sample will indicate the amount of specific carbohydrate present in the membrane to the respective lectin. The controls showed no precipitate ie. no agglutination occurred. This was expected as there was no lectins were introduced to the cells. This means there would be no lectin present to bind with its specific glyco-conjugate. In P201 strains that were untreated (not treated with trypsin) did not show any precipitate formation when it was incubated with the lectin as opposed to the treated cells of the same strain which showed agglutination to all of the lectins used. This shows that the use of trypsin to hydrolyse the proteoglycans in the cell membrane to enhance lectin interaction was effective. In untreated strains of P22 there was moderate agglutination for the HAA lectin and when the same strain was treated with trypsin and HAA the level of agglutination was unaffected. This indicated that there were sialic acid carbohydrates (Neu5Ac; GalNAc) specific for the HAA present on the cell surface membrane without treatment with trypsin and very few were within the cell surface membrane.
The visible absence of agglutination in untreated cells does not mean