Related Experiment Video
Updated: Aug 18, 2026
Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography
Published on: March 9, 2010
Isolation and partial characterization of a 30 kDa adhesin from Paracoccidioides brasiliensis
Patrícia Ferrari Andreotti1, Juliana Leal Monteiro da Silva, Alexandre Mello Bailão
1Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, UNESP, R. Expedicionários do Brasil, 1621, CEP 14.801-902, Araraquara, SP, Brazil.
Abstract:
The virulence of Paracoccidioides brasiliensis can be attenuated or lost after long periods of repeated subculturing and reestablished after animal inoculation. Only one adhesin (gp43) has been described until now, among the various identified components of P. brasiliensis, and gp43 shows adhesion to laminin. Thus, the present study was designed to isolate and characterize factors putatively related to the capacity of this fungus to adhere to the host by comparing P. brasiliensis samples, taken before and after animal inoculation. The two samples differed in their pattern of adhesion and invasion. The sample recently isolated from animals (Pb18b) demonstrated a greater capacity to adhere and to invade the Vero cells than the one subcultured in vitro (Pb18a). Extract from Pb18b also showed higher levels of protein expression than that from Pb18a, when two-dimensional electrophoresis gels were compared. A protein species of 30 kDa, pI 4.9, was more evident in the Pb18b extract and had properties of adhesin. Laminin, but none of the other extracellular matrix (ECM) components, such as fibronectin, collagen I and IV, bound specifically to the P. brasiliensis 30 kDa protein. The roles of 30 kDa and gp43 in cellular interactions were investigated and the adhesion of P. brasiliensis yeast cells was intensively inhibited by pre-treatment of epithelial cells with 30 kDa protein and gp43. Thus, this study presents evidence that adhesion capacity could be related to virulence, and that a 30 kDa adhesin accumulated differentially in samples with different levels of pathogenicity. This protein and its adhesion characteristics are being published for the first time and may be related to the virulence of P. brasiliensis.
Insights
Virulence in Paracoccidioides brasiliensis is linked to adhesion. A newly identified 30 kDa adhesin, along with gp43, enhances fungal adherence and invasion, potentially restoring virulence after animal inoculation.
Area of Science:
- Mycology
- Infectious Diseases
- Molecular Biology
Background:
- The virulence of Paracoccidioides brasiliensis can be lost through in vitro subculturing and regained after animal inoculation.
- The adhesin gp43, which binds laminin, is the only previously described adhesin for P. brasiliensis.
- Understanding fungal adherence factors is crucial for elucidating virulence mechanisms.
Purpose of the Study:
- To isolate and characterize factors involved in P. brasiliensis host adherence.
- To compare adherence and invasion capabilities of fungal samples with differing virulence.
- To identify novel adhesins potentially contributing to P. brasiliensis pathogenicity.
Main Methods:
- Comparison of P. brasiliensis samples before (Pb18a) and after (Pb18b) animal inoculation.
- Assessment of fungal adhesion and invasion of Vero cells.
- Two-dimensional electrophoresis to compare protein expression profiles.
- Characterization of protein-extracellular matrix interactions, including laminin binding.
Main Results:
- The P. brasiliensis sample recently isolated from animals (Pb18b) showed significantly higher adhesion and invasion of Vero cells compared to the in vitro subcultured sample (Pb18a).
- Pb18b extract exhibited higher protein expression than Pb18a.
- A 30 kDa protein with an isoelectric point of 4.9 was more abundant in Pb18b and demonstrated adhesin properties.
- This 30 kDa protein specifically bound to laminin, and both it and gp43 significantly inhibited P. brasiliensis yeast cell adhesion.
Conclusions:
- Adhesion capacity is strongly related to the virulence of P. brasiliensis.
- A novel 30 kDa adhesin, differentially accumulated in virulent fungal samples, plays a role in host cell interaction and may contribute to pathogenicity.
- This 30 kDa adhesin and its binding characteristics represent a new finding relevant to P. brasiliensis virulence.
