N-glycans detached from the 42 kDa cellular glycoprotein of in vitro propagated cactus (Mammillaria gracillis Pfeiff.) shoots, callus, hyperhydric regenerants and TW tumour were analyzed by mass spectrometry after in-gel deglycosylation of excised protein bands. Mixtures of N-glycans were shown by the electrospray MS analysis to be highly complex and heterogeneous. Only a low amount of high-mannose N-glycans was present, while the majority of structures were of the complex-type N-glycans. A single N-glycan structure was observed in the shoot sample, which appeared to be in good correlation with previous results. Similarities of assigned structures were revealed in the callus and tumour tissue while the highest number of different oligosaccharide structures was found in the hyperhydric regenerant. The presence of sialic acid as a constituent of N-glycans was indicated by lectin staining, ion exchange chromatography and molecular mapping by mass spectrometry, and could be correlated with the differentiation status of the tissues. Results obtained in this study indicate that different morphological levels can be correlated with the N-glycan composition of cellular glycoproteins.N-glikani, oslobođeni sa staničnoga glikoproteina od 42 kDa iz izdanka, kalusa, hiperhidriranoga regeneranta i tumora TW uzgojenih u kulturi tkiva kaktusa Mammillaria gracillis Pfeiff. analizirani su masenom spektrometrijom nakon deglikozilacije u gelu. Analiza masenom spektrometrijom ESI pokazala je kako su smjese oslobođ enih oligosaharida vrlo složene i heterogene, a većina struktura pripadala je kompleksnome tipu N-glikana. U uzorku izdanka opažena je samo jedna struktura, {to je u skladu s prija{njim rezultatima. Kalusno i tumorsko tkivo pokazalo je mnogo sličnosti u pripisanim strukturama dok je najveći broj različitih oligosaharida prona- đen u hiperhidriranome regenerantu. Na prisutnost sijalinske kiseline ukazala je inkubacija s lektinima, kromatografija ionske izmjene te masena spektrometrija. Rezultati dobiveni u ovim istraživanjima pokazuju da se stupanj organiziranosti tkiva može povezati sa sastavom N-glikana staničnih glikoproteina
