Candida albicans and Candida tropicalis Antigens Studied by SDS Polyacrylamide Gel Electrophoresis and Westernblot

Abstract

Summary: The SDS extracts of blastospores from 14 Candida albicans strains and from 8 Candida tropicalis strains were studied by SDS polyacrylamide gel electrophoresis. The Coomassie blue staining revealed more than 40 polypeptides; 4 from Candida albicans and 5 from Candida tropicalis were major polypeptides with molecular weights (M.W.) of 34 to 54 kDa. The extracts obtained by the mechanical disruption of yeasts cells and those obtained by the SDS whole‐cell treatment showed several differences especially with polypeptides ranging from 67 to 94 kDa and from 20 to 30 kDa – the major polypeptides were extracted by the both procedures. All the gels run with the SDS extracts from the strains of same species strains gave identical patterns but several polypeptides including the major ones showed different M.W. when extracted from Candida albicans or Candida tropicalis. However the antigens of these two species previously studied by quantitative Immunoelectrophoresis techniques (QIE) had shown more than 85% of cross‐reactions. (Gabriel‐Bruneau and Guinet 1984 [5]). The SDS extracted polypeptides have been electrophoretically transfered into nitrocellulose sheets and revealed with diluted Indian Ink. The corresponding band patterns were different from those and SDS‐PAGE as the sensitivity of this revelation was better for high M.W. (67 to 30 kDa) and lower if M.W. were less than 30 kDa. Thus the two species patterns were always easily distinct and the major polypeptides detected. Transfered polypeptides were also incubated with several rabbit sera: anti‐Candida albicans soluble extract, anti‐Candida tropicalis soluble extract, anti‐Candida albicans cell wall, anti‐sp2 (produced with an immunoaffinity chromatography purified antigen – Benbouzid et al., 1986 [1]). Polypeptides from surface biotin‐labeled yeast‐cells were incubated with avidin‐peroxydase. About 20 polypeptides were revealed with the anti‐soluble extract sera, about 10 with the anti‐cell wall ones and two with anti‐sp2. Only one to four of these polypeptides were strongly revealed. About 5 bands could come from yeast cell‐surface as they were fairly revealed by avidin‐peroxydase. One of the anti‐sp2 revealed band showed a 4 kDa variation of M.W. when it was extracted from Candida albicans or Candida tropicalis. The cross‐reactions between polypeptides with different M.W. could explain the apparent discrepancy between Q.I.E and SDS‐PAGE results. No serological differences among Candida albicans strains appeared with the sera tested. Zusammenfassung SDS‐Extrakte der Blastosporen von 14 Candida albicans‐ und 8 Candida tropicalis‐Stämmen wurden in der SDS‐Polyacrylamidgel‐Elektrophorese (SDS‐PAGE) untersucht. Die Coomassie‐Blau‐Färbung ergab mehr als 40 Polypeptide; 4 bei Candida albicans und 5 bei Candida tropicalis erwiesen sich als Hauptpolypeptide mit einem Molekulargewicht (MG) von 34 bis 54 kDa. Die Extrakte, die durch mechanisches Aufbrechen der Hefezellen und solche, die durch SDS‐Ganzzellbehandlung gewonnen worden waren, zeigten mehrere Unterschied...

SDS‐PAGE Protein Patterns of Yeasts from Human Sources: SDS‐Page‐Proteinmuster an Hefen hummer Herkunft

“…In particular C. albicans and C. tropicalis are probably very closely related with C. parupsilosis a near neighbour. Bruneau and Guinet (2) reported that SDS-PAGE traces of 14 C. albicuns isolates were identical as were those of 8 C. tropicalis isolates with much similarity between the two. They referred to their own data showing that 85 O h of antigens detected by immuno-electrophoresis were the same for these two species.…”