Laccase activity in Cryptococcus gattii strains isolated from goats

Area of Science:

• Mycology
• Veterinary Medicine
• Infectious Diseases

Background:

• Cryptococcosis is a serious fungal infection caused by *Cryptococcus* yeasts.
• Laccase enzyme is a significant virulence factor, enabling melanin production.
• Previous research primarily focused on *Cryptococcus neoformans* laccase activity.

Purpose of the Study:

• To evaluate laccase activity in *Cryptococcus gattii* serotype B strains from goats.
• To compare laccase activity between *C. gattii* and *C. neoformans* isolates.
• To investigate the role of laccase in cryptococcosis outbreaks in Spain.

Main Methods:

• Fungal cell rupture and supernatant collection.
• Enzymatic assay using L-dopa substrate.
• Quantification of laccase activity via absorbance at 450 nm (Enzymatic Units).

Main Results:

• Highest laccase activity (EU > 12) observed in *C. gattii* serotype B strains from goats.
• Lowest activity (EU = 0.7) found in an environmental *C. gattii* serotype C isolate.
• *C. neoformans* serotype A isolate showed 6.3 EU, lower than the highest *C. gattii* values.

Conclusions:

• *C. gattii* serotype B from goats demonstrates significant laccase activity, correlating with severe cryptococcosis outbreaks.
• Laccase is a major, though not exclusive, pathogenic factor in *Cryptococcus gattii*.
• Findings highlight the importance of laccase in *C. gattii* pathogenesis, particularly in animal hosts.