The fungus, known for causing yeast and other minor infections, also causes a sometimes-fatal infection known as candidemia in immunocompromised patients. An in vivo study, published in mBio, demonstrates how C. albicans can distinguish between a healthy and an unhealthy host and alter its physiology to attack.
“The ability of the fungus to sense the immune status of its host may be key to its ability to colonize harmlessly in some people but become a deadly pathogen in others,” said Jessica V. Pierce, BA, PhD student in the molecular microbiology program at the Sackler School of Graduate Biomedical Sciences at Tufts.
“Effective detection and treatment of disease in immunocompromised patients could potentially work by targeting the levels of a protein, Efg1p, that we found influenced the growth of Candida albicans inside the host,” she continued.
The researchers knew from previous research that Efg1p influences the expression of genes that regulate how harmful a fungal cell can become. Surprisingly, the investigators found that lower Efg1p levels allow the fungal cells to grow to high levels inside a host. Higher levels of the protein result in less growth.
To examine how the immune status could affect the growth of C. albicans within a host, the researchers fed both healthy and immunocompromised mice equal amounts of two fungal strains containing two different levels of the Efg1p protein.
Fecal pellets from the mice were tested to determine which strain of fungi thrived. In a healthy host, the fungal cells with higher levels of the protein predominated.
In immunocompromised mice, the fungal cells with lower levels of the protein flourished. The researchers noted that lack of interactions with immune cells in the intestinal tract most likely caused the necessary environmental conditions favoring fungal cells that express lower levels of the protein, resulting in fungal overgrowth and setting the stage for systemic infection.
“By having a mixed population with some high Efg1p cells and some low Efg1p cells, the fungus can adjust its physiology to remain benign or become harmful when it colonizes hosts with varying immune statuses. These findings are important because they provide the first steps toward developing more effective methods for detecting and treating serious and stubborn infections caused by Candida albicans, such as candidemia,” said Carol A. Kumamoto, PhD, professor of molecular biology and microbiology at Tufts University School of Medicine and member of the molecular microbiology and genetics program faculties at the Sackler School of Graduate Biomedical Sciences.
The immune system and “good bacteria” within the body act to regulate the size of C. albicans fungal populations in healthy individuals. When the immune system is compromised, the fungus can spread throughout the body. Candidemia, i.e. blood-borne Candida, is the fourth most common blood infection among hospitalized patients in the United States and is found in immunocompromised patients such as babies, those with catheters, and the critically ill.
mBio is an online-only, open access journal published in association with the American Society for Microbiology.
This research was supported in part by grants #AI076156, #AI08179, and #AI07422 from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health.
Pierce JV, Kumamoto CA. mBio. “Variation in Candida albicans EFG1 Expression Enables Host-Dependent Changes in Colonizing Fungal Populations.” July 24, 2012. DOI:10.1128/mBio.00117-12.
About Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences
Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts University are international leaders in innovative medical education and advanced research. The School of Medicine and the Sackler School are renowned for excellence in education in general medicine, biomedical sciences, special combined degree programs in business, health management, public health, bioengineering and international relations, as well as basic and clinical research at the cellular and molecular level. Ranked among the top in the nation, the School of Medicine is affiliated with six major teaching hospitals and more than 30 health care facilities. Tufts University School of Medicine and the Sackler School undertake research that is consistently rated among the highest in the nation for its effect on the advancement of medical science.
If you are a member of the media interested in learning more about this topic, or speaking with a faculty member at the Tufts University School of Medicine or another Tufts health sciences researcher, please contact Jennifer Kritz at 617-636-3707.
Jennifer Kritz | EurekAlert!
Researchers invent tiny, light-powered wires to modulate brain's electrical signals
21.02.2018 | University of Chicago
The “Holy Grail” of peptide chemistry: Making peptide active agents available orally
21.02.2018 | Technische Universität München
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences