Filamentous fungus; Hyphomycetes, Dematiaceae, Genus: Curvularia
Ecology;
There are numerous species of Curvularia, many of which are facultative pathogens of tropical or subtropical plants, but some species can be isolated in temperate agricultural areas. They are particularly common as saprobes or weak pathogens on grasses.
Macroscopic;
- Rapid growth
- Woolly texture
- Whitish colonies becoming olive brown on the surface and reverse.
Microscopic;
- Septate hyphae, generally brown in appearance
- Conidiophores brown, erect, simple or branched. geniculate (1), producing conidia in sympodial (2) order.
- Poroconidia (3), ellipsoidal, often gently curved (hence the name), brown in colour, usually with 3 to 4 true septa. Flat conidial scar on release.
- (Poro)conidia have transverse septa, ie. wall to wall and not distoseptate (4) as with Bipolaris species or Drechslera species.
Curvularia hyphae, Conidophores and Conida (LPCB X250)(Click on photo to enlarge for better viewing)
Curvularia - Multi-celled mature brown poroconidia (LPCB X400)(Click on photo to enlarge for better viewing)
Curvularia - conidiophore bearing curved, brown, multicelled conidia(click on photo to enlarge for better viewing)
(Center) Conidiophore with numerous conidia attached (LPCB X400)Note: 100 µm bar in upper right
(Click on photo to enlarge for better viewing)
3 Young conida attached at end of conidiophore (LPCB X400)(Click on photo to enlarge for better viewing)
Geniculate (bent) conidiophore bearing multicelled conidia (LPCB X400)(Click on photo to enlarge for better viewing)
Curvularia conidiophore with geniculate (bent) apical end bearing sympodially placed, curved, multicelled poroconidia (LPCB X400)(Click on photo to enlarge for better viewing)
Ditto - Geniculate (bent) distal end of conidiophore with still attached curved poroconidia(Click on photo to enlarge for better viewing)
Not tremendously pathogenic, however, may be found in immunocompromised patients with increasing frequency. Reports of infection following traumatic injury. Occasionally found causing onychomycosis, keratitis, sinusitis, mycetoma, pneumonia, endocarditic, cerebral abscesses and disseminated infection. Mycetomas are most frequently found in animals.
(1) Geniculate - bent abruptly, as in a bent knee.
(2) Sympodial - continued, successive apical growth with each subsequent point of growth next to the previous one and terminating at somewhat higher level.
(3) Poroconidia - conidia produced through a pore in the conidiophores.
(4) Distoseptate - conidia subdivided by inner wall layer only. A thin septum lacking a septal plate and penetrated by cytoplasm junctions, possibly formed by invagination from the lateral wall.
