Mold Biology & Identification Flashcards

Which mold is considered a primary colonizer in water-damaged buildings, typically appearing within 24–48 hours of a moisture event?

Answer: Penicillium chrysogenum

Penicillium species are rapid primary colonizers that can establish growth within 24–48 hours of a moisture event due to their low water activity requirements.

The process by which mold hyphae fuse together to form a network is called:

Answer: Anastomosis

Anastomosis is the fusion of hyphae from the same or compatible fungal colonies, allowing nutrient and signal transfer through the mycelial network.

Penicillium and Aspergillus spores are often confused. The key microscopic difference is that Penicillium has:

Answer: A brush-like branching structure (penicillus) without a terminal vesicle

Penicillium has a characteristic brush-like (penicillate) arrangement of phialides without a swollen terminal vesicle, while Aspergillus has a distinct vesicle at the conidiophore apex.

Which mold species produces trichothecene mycotoxins and is associated with 'sick building syndrome' investigations?

Answer: Stachybotrys chartarum

Stachybotrys chartarum produces trichothecene mycotoxins (satratoxins) that are among the most potent fungal toxins linked to building-related illness.

What is the significance of mold producing 'microbial volatile organic compounds' (MVOCs)?

Answer: They are metabolic byproducts that cause musty odors and may indicate hidden mold growth

MVOCs are metabolic byproducts of active mold growth that create characteristic musty odors and can indicate hidden mold growth even when visual inspection is inconclusive.

Which mold genus is characterized by large, dark, multicellular conidia with both transverse and longitudinal septa (muriform conidia)?

Answer: Alternaria

Alternaria produces distinctive muriform (brick-like) conidia with both cross and lengthwise septa, which are characteristic of this genus.

In which part of a building would you be MOST likely to find Serpula lacrymans, a mold-like organism associated with 'dry rot'?

Answer: Basement wood framing with repeated wetting and drying cycles

Serpula lacrymans causes dry rot in structural wood, thriving in basement and crawlspace wood framing that undergoes cycles of wetting and drying.