Mesophilic · Extended-panel species

Ulocladium botrytis

Water-damage indicator closely related to U. chartarum. Strong substrate association with damp wallpaper, painted drywall, and textiles.

Extended panelMesophilic · Aw ≥ 0.88

Moisture niche · where this species can grow

XerophilicAw < 0.80
MesophilicAw 0.80–0.89
HydrophilicAw ≥ 0.90
Min Aw 0.88
← Drier conditions toleratedRequires liquid water →
Minimum Aw
0.88
EPA reference (GM)
< 0.4 SE/mgMeklin AHHS threshold
Mycotoxin profile
3+ documented
Ecological role
Secondary colonizer

The < 0.4 SE/mg reference value is Meklin 2004's AHHS exclusion threshold: the paper retained species whose geometric mean was at least 2 spores per 5 mg dust (≈ 0.4 spores/mg) and eliminated the rest. This species was measured across the 1,096-home AHHS sample and characterized below that threshold, used here as a conservative ceiling on its true GM, not a percentile band. A detected value of X SE/mg implies an elevation factor of at least X ÷ 0.4 over the EPA reference, a lower bound, since the true GM is below 0.4. See the 82-species story for the math.

Note on cardinal Aw: Estimated by analogy with U. chartarum (0.86–0.88); species-specific cardinal values not formally published for U. botrytis.

About Ulocladium botrytis

Ulocladium botrytis is a cellulolytic Ulocladium closely related to U. chartarum, with similar substrate associations on water-damaged building materials. It is offered on EnviroBiomics's ERMI Plus add-on and on Mycometrics's Budget 15 / Signature panels as one of the more reliable water-damage indicator species beyond the EPA's 36-panel.

Taxonomy

Ascomycota → Dothideomycetes → Pleosporales → Pleosporaceae → Ulocladium. The genus was largely synonymized with Alternaria section Ulocladioides in a 2013 molecular revision; the historic genus name persists in mycological practice.

Ecology and habitat

Ulocladium species are dematiaceous (dark-pigmented) saprophytes on damp cellulose, with cosmopolitan distribution. U. botrytis occurs on plant material, paper, and damp building substrates worldwide. The genus's modern taxonomic placement (per a 2013 molecular revision) is within Alternaria section Ulocladioides; the historic Ulocladium genus name is retained in laboratory practice.

Indoor relevance

U. botrytis is associated with damp wallpaper, painted drywall, gypsum board paper, and textiles[4]. Like its close relative U. chartarum, the species is one of the more diagnostically reliable water-damage indicators in indoor mycology, detection on a dust panel signals active or recent moisture damage regardless of mycotoxin status.

Cardinal physiology

Minimum water activity for growth: estimated Aw ≈ 0.88[2] by analogy with U. chartarum (0.86–0.88); species-specific cardinal values for U. botrytis are not formally published. Growth across 5–35 °C with optimum near 25 °C. The species sits in the upper mesophilic / lower hydrophilic range.

Secondary metabolites

U. botrytis's mycotoxin profile is modest. The most distinctive metabolite is ulocladol, a tyrosine kinase (p56lck) inhibitor specific to U. botrytis. Genus-wide metabolites include infectopyrones and altertoxin I derivatives[3]. Notably, despite the close taxonomic placement within Alternaria section Ulocladioides, Andersen & Hollensted 2008 found that none of 52 Ulocladium strains produced alternariols, tenuazonic acid, altersolanols, or macrosporin, metabolites commonly produced by core Alternaria species. Curvularin production within the genus is specific to U. atrum, not U. botrytis. None of these are major commercial urine-panel targets. The species's diagnostic value rests on its strong substrate-association with active moisture damage, not on its toxigenic profile.

Compounds documented as produced by Ulocladium botrytis (presence and quantity vary by chemotype, strain, and substrate):

Ulocladol (tyrosine kinase inhibitor; specific to U. botrytis)Infectopyrones (genus-wide)Altertoxin I derivatives

DNA-based detection of a mycotoxin-producing species in household dust does not directly establish exposure to that mycotoxin at any specific concentration.

Lab availability

Some commercial dust testing labs offer this species as an extended-panel option. Specific lab coverage changes over time: check with your laboratory for current panel options.

Related

Alternaria alternataTaxonomically related; Ulocladium was synonymized into Alternaria sect. Ulocladioides in 2013.Beyond the 36

References

  1. Meklin T, Haugland RA, Reponen T, Varma M, Lummus Z, Bernstein D, Wymer LJ, Vesper SJ. Quantitative PCR analysis of house dust can reveal abnormal mold conditions. J Environ Monit. 2004;6(7):615–620.
  2. Pitt JI, Hocking AD. Fungi and Food Spoilage. 3rd ed. New York: Springer; 2009.
  3. Andersen B, Hollensted M. Metabolite production by different Ulocladium species. Int J Food Microbiol. 2008;126(1–2):172–179.
  4. Andersen B, Frisvad JC, Søndergaard I, Rasmussen IS, Larsen LS. Associations between fungal species and water-damaged building materials. Appl Environ Microbiol. 2011;77(12):4180–4188.