In vitro identification of the cytoskeleton proteins of Giardia lamblia using a MS technique.

Objective To identify the cytoskeletal proteins of Giardia lamblia trophozoites in vitro using mass spectrometry. Methods G.lamblia was cultured axenically with modified TYI-S-33 medium.Total protein from trophozoites was extracted and quantified using Bradford's method.Then,the samples were subjected to 2D-protein electrophoresis and electrophoresis gels were stained with silver nitrate.The number and types of protein spots scanned by image scanning were determined and analyzed using Image Master TM 2D 5.0 software.Information on matching protein spots was obtained and matching protein spots were selected for mass spectrometry(MALDI-TOF MS) analysis.Results The total protein content was(4.8241±8)μg/ml.Two-dimensional gel electrophoresis map analysis identified about 1 253 protein spots covering the entire gel.Protein spots were concentrated and expressed a high level of protein,and proteins were richly colored,bright,and distinct.From among 80 well-matched protein spots,mass spectrometry analysis identified 5 categories of 46 kinds of proteins.Six(14 points) were the cytoskeleton proteins α-giardin,β-giardin,γ-giardin,δ-giardin,centrin,and phase-1 flagellin.Eighteen were metabolic enzymes or associated proteins(28 spots),5 were translated transcription proteins(5 spots),3 were other proteins(3 spots),and 6 spots could not be identified.Conclusion An MS technique can be used to identify the cytoskeleton proteins of Giardia lamblia trophozoites in vitro.