Related Experiment Video
Updated: Aug 8, 2026
07:32
Biolistic Transformation of a Fluorescent Tagged Gene into the Opportunistic Fungal Pathogen Cryptococcus neoformans
Published on: March 19, 2015
Characterization of a flocculation-like phenotype in Cryptococcus neoformans and its effects on pathogenesis
Li Li1, Oscar Zaragoza, Arturo Casadevall
1Department of Medicine, Department of Microbiology and Immunology, Albert-Einstein College of Medicine, Ullmann Building 1223, 1300 Morris Park Ave, Bronx, NY 10461, USA.
Cellular Microbiology
|June 9, 2006
Summary
Cryptococcus neoformans exhibits transient cell aggregation, impacting host-pathogen interactions. This flocculation enhances adherence and phagocytosis, influencing disease severity and survival in mice.
Area of Science:
- Mycology
- Immunology
- Pathogenesis
Background:
- Cryptococcus neoformans is an opportunistic fungal pathogen causing cryptococcosis.
- Cell-cell aggregation, or flocculation, is a poorly understood phenomenon in C. neoformans.
- Understanding phenotypic changes is crucial for deciphering host-pathogen dynamics.
Purpose of the Study:
- To investigate the characteristics and implications of cell-cell aggregation in Cryptococcus neoformans.
- To determine how this transient flocculation affects host-pathogen interactions.
- To explore the potential mechanisms underlying cell aggregation.
Main Methods:
- Studied a serotype D strain of C. neoformans (ATCC 24067, isolate RC-2).
- Observed cell aggregation during different growth phases and its dependence on culture medium.
- Assessed cell adherence to J774.16 macrophages and phagocytosis (in vitro and in vivo).
- Evaluated the impact of infection with aggregated versus non-aggregated cells on mouse survival and fungal burden.
Main Results:
- Cell aggregation (clump+ cells) occurred in early log phase and resolved in stationary phase (clump- cells).
- Aggregation was medium-dependent and reversible by vortexing or proteinase K treatment.
- Clump+ cells showed significantly enhanced adherence to macrophages and higher complement-mediated phagocytosis.
- In vivo, infection with clump+ cells led to lower fungal burden and increased survival in mice.
Conclusions:
- Transient cell aggregation in C. neoformans significantly alters host-pathogen interactions.
- Phenotypic changes during flocculation impact fungal adherence and phagocytosis, affecting disease pathogenesis.
- Hypothesize that protein content changes in the polysaccharide capsule drive aggregation.
- Findings highlight the complexity of host-pathogen interactions and may explain assay inconsistencies.
Related Concept Videos
01:27Cryptococcal 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,...
01:25Colonisation of Pathogens
Pathogen colonization of host tissues is a critical step in the development of infectious diseases. Various pathogenic microorganisms, including bacteria, fungi, viruses, and protozoa, have evolved complex strategies to attach to, invade, and persist within host environments. These mechanisms enable pathogens to establish infections, evade immune responses, and resist antimicrobial treatments.Attachment to Host CellsIn bacteria, colonization typically begins with adherence to host epithelial...
01:28Fungal 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...
01:29Fungal Group Zygomycota
Zygomycota, previously classified as a distinct fungal group, are primarily terrestrial, saprophytic molds that play a crucial role as decomposers. Recent phylogenetic studies have revealed that these fungi are now divided into two major clades — Mucoromycota, which includes many symbiotic species, and Zoopagomycota, which primarily consists of parasitic and pathogenic fungi. These groups exhibit distinct ecological roles and reproductive strategies while sharing key structural and...