Related Experiment Video

Updated: Jun 19, 2026

Live Imaging of Antifungal Activity by Human Primary Neutrophils and Monocytes in Response to A. fumigatus
12:29

Live Imaging of Antifungal Activity by Human Primary Neutrophils and Monocytes in Response to A. fumigatus

Published on: April 19, 2017

A fungal pH-responsive signaling pathway regulating Aspergillus adaptation and invasion into the cornea

Xia Hua1, Xiaoyong Yuan, Kirk R Wilhelmus

  • 1Sid W Richardson Ocular Microbiology Laboratory, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas 77030, USA.

Investigative Ophthalmology & Visual Science
|October 24, 2009
PubMed
Abstract

Insights

Mutations in palB and pacC genes of Aspergillus nidulans attenuated fungal invasion of the cornea. The PacC pathway is crucial for regulating fungal filamentation during corneal infections.

Area of Science:

  • Mycology
  • Pathogenesis
  • Molecular Biology

Background:

  • Aspergillus nidulans is a fungus that can cause opportunistic infections.
  • pH-responsive pathways are essential for fungal adaptation and virulence.
  • The PalB and PacC proteins are components of a pH-sensing system in A. nidulans.

Purpose of the Study:

  • To investigate the role of PalB and PacC in the pathogenesis of Aspergillus nidulans corneal infections.
  • To determine how these pH-responsive pathway components affect fungal invasion and filamentation in the cornea.

Main Methods:

  • Utilized wild-type, palB, and pacC loss-of-function mutants of A. nidulans.
  • Assessed fungal growth kinetics in vitro under varying pH conditions.
  • Evaluated corneal virulence ex vivo using scarified porcine and human corneas.

Main Results:

  • palB and pacC mutants showed significantly reduced hyphal invasion of corneal stroma compared to wild-type A. nidulans.
  • In vitro growth rates were similar in liquid media but the pacC mutant exhibited slower growth on solid media.
  • Reconstituted strains restored virulence to wild-type levels, confirming gene function.

Conclusions:

  • palB and pacC mutant strains of A. nidulans exhibit attenuated corneal invasion.
  • The PacC pathway plays a significant role in regulating fungal filamentation during Aspergillus corneal infections.
  • Targeting this pathway could offer strategies for treating fungal keratitis.

More Related Videos

Assay for Adhesion and Agar Invasion in S. cerevisiae04:36

Assay for Adhesion and Agar Invasion in S. cerevisiae

Published on: November 8, 2006

Related Concept Videos

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...
Yeast Signaling01:28

Yeast Signaling

Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
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...
Fungal Phylum Microsporidia01:28

Fungal Phylum Microsporidia

Microsporidia are a group of obligate intracellular fungi that were initially classified as protists but were later reclassified based on phylogenetic, molecular, and structural evidence linking them to the Chytridiomycota. These unicellular, non-motile organisms are highly specialized parasites that infect a wide range of animal hosts, including humans. They have evolved extensive genomic and metabolic reductions, making them highly dependent on their hosts for survival.Morphology and Genomic...
Intracellular Signaling Affects Focal Adhesions01:17

Intracellular Signaling Affects Focal Adhesions

Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Fungal Phylum Basidiomycota01:26

Fungal Phylum Basidiomycota

Basidiomycota is a diverse phylum of fungi that includes ecologically significant decomposers such as white rot fungi, symbionts like mycorrhizal fungi, plant pathogens such as rusts and smuts, and edible species like Agaricus bisporus (the common button mushroom). These fungi play crucial roles in nutrient cycling, symbiotic relationships, and even human health. Their defining feature is the basidium, a microscopic club-shaped structure responsible for producing basidiospores.Fruiting Bodies...