Related Experiment Video

Updated: Aug 21, 2026

Histological Quantification to Determine Lung Fungal Burden in Experimental Aspergillosis
09:52

Histological Quantification to Determine Lung Fungal Burden in Experimental Aspergillosis

Published on: March 9, 2018

Cytotoxic substances from Aspergillus fumigatus in oxygenated or poorly oxygenated environment

Akira Watanabe1, Katsuhiko Kamei, Toshikazu Sekine

  • 1Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University, Chiba City, Japan. fewata@restaff.chiba-u.jp

Mycopathologia
|October 19, 2004
PubMed

Insights

Oxygen levels impact Aspergillus fumigatus virulence. Higher oxygen (20%) boosts gliotoxin production, a key cytotoxic substance, though other factors also contribute to fungal damage.

Area of Science:

  • Medical Mycology
  • Environmental Microbiology
  • Pathogen Virulence Factors

Background:

  • Aspergillus fumigatus is an opportunistic fungal pathogen causing significant human health issues.
  • The respiratory tract, a common infection site, is exposed to varying oxygen concentrations.
  • Oxygen levels are hypothesized to influence A. fumigatus virulence and toxin production.

Purpose of the Study:

  • To investigate the effect of different oxygen concentrations on A. fumigatus growth.
  • To assess the impact of oxygen on the production of cytotoxic substances, including gliotoxin.
  • To explore the relationship between oxygen, fungal growth, and cytotoxicity.

Main Methods:

  • Two clinical A. fumigatus strains were cultured at 10%, 14%, and 20% oxygen.
  • Culture filtrates were tested for cytotoxicity against murine macrophages.
  • Fungal growth was quantified.
  • Filtrate components were analyzed using gas chromatography-mass spectrometry.

Main Results:

  • All culture filtrates contained gliotoxin and exhibited potent macrophage cytotoxicity.
  • Gliotoxin production was significantly lower at 10% oxygen compared to higher concentrations.
  • Despite reduced gliotoxin at 10% oxygen, fungal growth and overall filtrate cytotoxicity showed negligible decrease.
  • Gas chromatography-mass spectrometry identified gliotoxin and suggested the presence of other cytotoxic substances.

Conclusions:

  • Well-oxygenated conditions (e.g., 20% oxygen) favor gliotoxin production in A. fumigatus.
  • Cytotoxic substances other than gliotoxin likely play a significant role in A. fumigatus-mediated damage.
  • Oxygen tension is a critical environmental factor modulating A. fumigatus virulence.

More Related Videos

Isolation of Culturable Yeasts and Molds from Soils to Investigate Fungal Population Structure10:33

Isolation of Culturable Yeasts and Molds from Soils to Investigate Fungal Population Structure

Published on: May 27, 2022

Related Concept Videos

Oxygen Requirements and Growth Patterns01:29

Oxygen Requirements and Growth Patterns

Microorganisms exhibit diverse oxygen requirements and growth patterns driven by their metabolic strategies and environmental adaptations. Oxygen, while essential for many organisms, can also be toxic under certain conditions, shaping how microorganisms grow and survive.Oxygen Requirements of MicroorganismsMicroorganisms are classified based on their ability to use or tolerate oxygen:● Obligate aerobes like Mycobacterium tuberculosis need oxygen for energy production, as it serves as the...
Fungal Phylum Ascomycota01:28

Fungal Phylum Ascomycota

Phylum Ascomycota, a major division within the subkingdom Dikarya, comprises a diverse range of fungal species, including both unicellular yeasts and filamentous molds such as Aspergillus and Penicillium. These fungi thrive in a variety of habitats, from aquatic ecosystems to terrestrial environments, playing crucial ecological and economic roles.Morphology and ReproductionThe defining characteristic of Ascomycetes, commonly referred to as sac fungi, is the ascus—a sac-like structure that...
Antifungal Agents01:15

Antifungal Agents

Amphotericin B is a broad-spectrum antifungal agent that exploits structural differences between fungal and mammalian cell membranes. Its amphipathic structure—featuring a hydrophobic polyene-lactone ring and a hydrophilic region containing mycosamine and carboxylic acid groups—enables selective binding to ergosterol, a sterol predominantly found in fungal plasma membranes. This selective interaction underlies the drug’s antifungal activity, although weak binding to cholesterol contributes to...
Bioreactor Controls-II01:18

Bioreactor Controls-II

In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...
Cryptococcal Meningitis01:27

Cryptococcal Meningitis

Cryptococcal meningitis is a life-threatening opportunistic infection predominantly associated with HIV/AIDS, accounting for over 100,000 deaths annually worldwide. However, it also affects individuals with other forms of immunosuppression, including those undergoing immunosuppressive therapy, organ transplant recipients, patients with innate immunodeficiencies, and individuals with hematological disorders. The infection is caused mainly by Cryptococcus neoformans and Cryptococcus gattii,...