Autofluorescence Is a Common Trait in Different Oceanic Fungi

Area of Science:

• Marine Mycology
• Biophotonics
• Oceanic Microbiology

Background:

• Natural autofluorescence is a known phenomenon in various organisms, offering insights into physiological states.
• Terrestrial and human-associated fungi exhibit autofluorescence, but pelagic fungi remain unexamined.
• Marine fungi are crucial to oceanic ecosystems, yet their optical properties are largely unknown.

Purpose of the Study:

• To investigate the existence and intensity of autofluorescence in pelagic marine fungi.
• To assess how growth stages and nutrient availability affect fungal autofluorescence.
• To determine the impact of autofluorescence on fluorescent staining methods like DAPI co-staining.

Main Methods:

• Culturing five distinct pelagic fungal isolates under varying growth and nutrient conditions.
• Measuring autofluorescence intensity across different species and excitation wavelengths.
• Analyzing the influence of physiological state on autofluorescence.
• Evaluating interference with DAPI (4′,6-diamidino-2-phenylindole) staining.

Main Results:

• All studied marine pelagic fungi demonstrated autofluorescence.
• Autofluorescence intensity varied significantly between species and was dependent on excitation wavelength.
• Fungal autofluorescence intensity was modulated by growth stage and nutrient concentration.
• Natural autofluorescence can potentially interfere with fluorescent probe staining.

Conclusions:

• Marine fungi are inherently autofluorescent, with intensity being species- and condition-dependent.
• Oceanic fungal autofluorescence must be accounted for in studies using fluorescent probes, such as fluorescence in situ hybridization.
• Failure to consider autofluorescence may lead to misinterpretation of experimental results in marine fungal research.