Saturday 31 March 2012

Scopulariopsis brevicaulis

Scopulariopsis brevicaulis (Teleomorph: Microascus brevicaulis?*) Fungus

Compare to Scopulariopsis brumptii.

Ecology: Cosmopolitan distribution. The genus has many species - frequently isolated from soil as well as plants and insects.
Pathogenicity: Weakly karatinolytic, S.brevicaulis has been implicated in cases of onychomycosis. Other conditions such as endopthalmitis & endocarditis and skin lesions have also been reported. As with many opportunistic fungi, immunocompromised patients may be at greater risk of infection.
Physiology: The optimal growth range is between 24 – 30oC, with a maximum of 37oC.
Macroscopic Morphology: Colonies (SAB at 30oC pictured below) exhibit moderately rapid growth, reaching maturity in about one week. Colonies are velvety to powdery in texture. Colour may start off as white, quickly becoming a pinkish-brown or buff to cinnamon. Reverse is a honey to golden-brown in colour. Colouration varies with each Scopulariopsis species.
Scopulariopsis brevicaulis on SAB after 5 days at 30oC.
Microscopic Morphology: Hyphae are hyaline and septate. Conidophores extend from hyphae and terminate in brush-like groups of 2 – 4 annellophores (conidiophores). Annelloconidia are globose to ovoid with a truncate base, about 5-9 X 5-7 µm in size and have a fine to coarsely roughened wall texture.
Scopularioposis brevicaulis is frequently encountered in the laboratory and can be distinguished from Scopulariopsis brumptii as the latter has short swollen conidiophores and has a grey to greyish-black appearance macroscopically.
*Teleomorph – sources differ. One states there is no teleomorph for this species while another states Microascus brevicaulis is its teleomorph stage. I’ll leave this discrepancy to be pursued by those interested.
All photos below taken with the Leica DMD-108 Microscope
Note: Size may appear to vary between photos of equal magnification due to cropping of photos prior to posting. The DMD-108 microscope has an additional 10X digital magnification factor that can be added to the optical magnification of each particular objective. While I try to take accurate note of each magnification used, errors on my part will undoubtedly occur when taking perhaps hundreds of photos on each organism. While magnification obviously increases the size of the structure being viewed, you may wish to give more weight to the detail and/or resolution of the the magnification provides.
(Click on any photo to enlarge for better viewing)
Scopulariopsis brevicaulis -Slide culture at 48hrs (LPCB X100)
(not much detail to see but included just for scale)
Scopulariopsis brevicaulis -Slide Culture (LPCB X250)
Scopulariopsis brevicaulis - brush-like structure of annellophores (conidiophore) bearing annelloconidia (LPCB X400)
Scopulariopsis brevicaulis - younger culture showing chains of annelloconidia extending from individual annellophores (conidiophores) (LPCB X400)
Scopoulariopsis brevicaulis - brush-like arrangement of annellophores bearing annelloconidia
(LPCB X400)
Scopulariopsis bdrevicaulis - a closer look at the brush-like structured described above. Note the rough texture on the conidia walls.
(LPCB X1000)
Scopulariopsis brevicaulis (LPCB X1000)
Okay, maybe too many photos, but I always get frustrated while consulting even the best fungal reference books and finding one tiny B&W photo crammed in at the bottom of the page which attempts to illustrate every feature. I think seeing several photos, even of the same structure, gives one a better perspective on the organism's characteristics.
Scopulariopsis brevicaulis - Brush-like branched annellophores bearing annelloconidia.
(LPCB X1000)
Scopulariopsis brevicaulis Annelloconidia- Okay, last photo. Note the ovoid structure of the annellocondia - 'annello' because of the truncated (flattened) base where they were attached to the annellophore, or simply the conidiophore. (LPCB X1000)

Beauveria species

Beauveria species (probable bassiana) -Fungus

Ecology: A cosmopolitan fungus commonly isolated from soil.

Pathogenicity: Low pathogenicity for humans however reports of keratitis and pulmonary infections have been reported in immunocompromised patients. Commonly considered to be a contaminant. Some Beauveria species are recognized as important insect pathogens particularly as the agent of muscardine disease of the silkworm.

Macroscopic Appearance: Beauveria is a moderately rapid growing fungus. Texture has been described as floccose,velvety, powdery to cottony. The isolate I present below has the appearance of a dollop of shaving cream dispensed from pressurized can. The colour is generally a bone white which can take on a pale yellow tinge with age. The reverse is a non-descript pale colour.

Microscopic Appearance: Hyphae are rather narrow and septate. Conidiogenous cells may grow singly or aggregate in dense clusters along the hyphae. They appear inflated at the base then become thinner at the apex giving a flask-like appearance. At the terminus there is what most sources describe as a thin zigzag filament or extension which bears a conidium at each bend (sympodial geniculate growth). Conidia are single celled, hyaline, smooth walled, round to oval and about 2-4µm in diameter, each singly attached via a fine denticle.

Beauvaria species on SAB after 5 Days at 30oC

(My isolate looked like canned shaving cream)

Beauveria species, slide culture (LPCB X200 Nikon)

Beauveria species, slide culture (LPCB X400 Nikon)

Beauveria species, slide culture (LPCB X400 DMD-108)

(Many clusters of conidiodgenous cells)

Beauveria species, slide culture (LPCB X400 DMD-108)

Beauveria species (LPCB -oops, magnification not noted)

(Resolution at magnification not sufficient to show attachment of conidia)

Beauveria species (oops, magnification not noted)

Beauveria species - both individual conidiogenous cells and clusters seen

I will try to get a higher magnification photo of the conidiogenic cell bearing the conidia from the zigzag like apex. I seem to lose the resolution on the photos or they are so overgrown with conidia that the structure is obscured. Stay tuned...

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