An extracellular matrix glues together the aerial-grown hyphae of Aspergillus fumigatus.
Pulmonary infections due to Aspergillus fumigatus result from the development of a colony of tightly associated hyphae in contact with the air, either in the alveoli (invasive aspergillosis) or in an existing cavity (aspergilloma). The fungal ball observed in vivo resembles an aerial colony obtained in agar medium in vitro more than a mycelial mass obtained in liquid shaken conditions that have been classically used to date to study A. fumigatus physiology. For this reason, we embarked on an analysis of the characteristics of A. fumigatus colonies grown in aerial static conditions. (i) Under static aerial conditions, mycelial growth is greater than in shaken, submerged conditions. (ii) The colony surface of A. fumigatus revealed the presence of an extracellular hydrophobic matrix that acts as a cohesive linkage bonding hyphae into a contiguous sheath. (iii) The extracellular matrix is composed of galactomannan, alpha1,3 glucans, monosaccharides and polyols, melanin and proteins including major antigens and hydrophobins. (iv) A. fumigatus colonies were more resistant to polyenes than shake, submerged mycelium. This is the first analysis of the three dimensional structure of a mycelial colony. Knowledge of this multicellular organization will impact our future understanding of the pathobiology of aerial mold pathogens.
Beauvais
Anne
A
Aspergillus Unit, Institut Pasteur, Paris, France. abeauvai@pasteur.fr
Schmidt
Christine
C
Guadagnini
Stéphanie
S
Roux
Pascal
P
Perret
Emmanuelle
E
Henry
Christine
C
Paris
Sophie
S
Mallet
Adeline
A
Prévost
Marie-Christine
MC
Latgé
Jean Paul
JP
D000595:Amino Acid Sequence; D000818:Animals; D001228:Aspergillosis / Q000382:microbiology*; D001232:Aspergillus fumigatus / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D005109:Extracellular Matrix / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D025301:Hyphae / Q000378:metabolism*; D008297:Male; D051379:Mice; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D025282:Mycelium / Q000737:chemistry / Q000648:ultrastructure; D016415:Sequence Alignment