Candida albicans

A tiny living thing lives in you.

It stays in your mouth and gut. Most of the time it is fine. But sometimes it grows too much. This can make you feel sick.

It can also live outside your body. This tiny thing can change its shape. It can look like round balls. It can also grow long like threads. This helps it live in different places. It can even make small seeds to stay safe.

These seeds help it survive heat or dry air. It is a very busy little life.

Candida albicans is a tiny fungus. It is a type of yeast. Many healthy adults have it in their mouths or guts.

Most of the time, it lives there without causing trouble. But sometimes, it grows too much. This can cause an infection called candidiasis. This is also called thrush.

This fungus is very good at changing its shape. This is called being polyphenic. It can grow as round yeast cells. It can also grow long, thin threads called hyphae. These threads help it move into body tissues.

It can also make tiny seeds called chlamydospores. These seeds help it survive when it is too hot or dry. Scientists study it in labs to learn about fungi. They use different food to see how its shape changes. Some strains can even switch between white and opaque forms. This helps the fungus live in many different places. It is a very smart little survivor.

Candida albicans is a common type of yeast that lives inside many people. It is often found in the mouths and guts of 40% to 60% of healthy adults.

Most of the time, this fungus is a commensal, which means it lives there without causing harm. However, it can become a pathogen, or a germ that causes sickness, if it grows too much. This overgrowth leads to an infection called candidiasis, which is also known as thrush. For people with weak immune systems, this fungus can be quite serious. In the United States, hospital infections from this fungus cause between 2,800 and 11,200 deaths every year.

This fungus is amazing because it can change its shape to survive. This ability is called being polyphenic. It can grow as round, oval yeast cells that move through the bloodstream.

When the environment changes, it can grow long, thin threads called hyphae. These hyphae help the fungus push into body tissues and organs. It can also create tiny spores called chlamydospores. These spores help the fungus stay alive during harsh, dry, or hot times. The fungus changes its shape based on things like temperature, nutrients, or the amount of CO2 around it.

People have known about this fungus for a very long time. The oldest mention of thrush likely comes from the work of Hippocrates. He wrote about oral infections in his book, Of the Epidemics, around 400 BC. The name itself comes from Latin words. "Candida" means shining white, and "albicans" means becoming white.

Because it has so many different names, scientists have used more than one hundred synonyms to describe it. There are also over 200 different species within the larger Candida genus.

Scientists use Candida albicans to study how other fungi work in a lab. It is a very good model organism for this kind of research. The fungus has a genome, which is the complete set of genetic instructions, that has been fully sequenced. This makes it one of the first fungi to be completely mapped out. The diploid genome size is about 29 Mb.

Interestingly, up to 70% of its protein coding genes have not been fully understood yet. Researchers use special tools like CHROMagar Candida to help identify different species in their studies.

Understanding this fungus helps us understand how living things adapt to change. Just like you might change your clothes for different weather, this fungus changes its body to fit its surroundings. It uses a special genetic code that is slightly different from many other organisms. For example, it uses a specific codon, or genetic instruction, to signal for a different amino acid than most others do. This change might help the fungus handle stress. By studying how it switches between white and opaque forms, scientists learn how life survives in a changing world.

Candida albicans is an opportunistic pathogenic yeast. It is a common member of the human gut flora. This fungus is found in the mouths and gastrointestinal tracts of 40% to 60% of healthy adults. Most of the time, it is a commensal organism. This means it lives in the body without causing harm. However, it can become a pathogen under certain conditions. This is especially true for immunocompromised individuals. An overgrowth of this fungus results in an infection called candidiasis. This condition is also commonly referred to as thrush.

The fungus is highly adaptable due to its morphology. It is often called a dimorphic fungus because it grows as both yeast and filamentous cells. However, it is more accurately described as polyphenic or pleomorphic. This means it can exhibit several different morphological phenotypes. These include the opaque, GUT, and pseudohyphal forms. The transition from yeast to hyphae is a rapid process. This process, called filamentation, is induced by environmental factors. Yeast cells are roughly 10 to 12 microns in size. Hyphal cells are thought to be important for tissue penetration and colonization. They may also help the fungus escape from macrophages.

Environmental factors trigger these morphological shifts. Changes in temperature, CO2 levels, nutrients, and pH can cause the fungus to change. For example, a medium that mimics a human host promotes filamentous growth. The cAMP-PKA signaling cascade is crucial for this morphogenesis. A transcriptional regulator called EFG1 also helps control the switch to filamentous cells. Additionally, C. albicans can form chlamydospores. These are spores that form on pseudohyphae. They are thought to help the fungus survive unfavorable conditions, such as heat or dryness.

C. albicans also undergoes high-frequency switching. This is a spontaneous process that happens independently of the environment. During this switching, different cellular morphologies are generated. In some strains, such as 3153A, at least seven different colony morphologies can be produced. This switching is reversible. One well-studied system is the white-to-opaque switching. This is an epigenetic process. David R. Soll and his colleagues discovered two of these switching systems. Another important factor is the SIR2 gene. In other yeasts, SIR2 is involved in chromosomal silencing. In C. albicans, SIR2 is implicated in phenotypic switching.

The history of this fungus stretches back thousands of years. The oldest reference to thrush likely dates to 400 BC. This mention is found in the work Of the Epidemics by Hippocrates. The name Candida albicans has a redundant etymology. "Candida" comes from the Latin word candidus, meaning shining white. "Albicans" is a present participle meaning becoming white. This makes the name a tautology, similar to saying "pure white becoming white." There are over 200 species in the Candida genus. More than one hundred synonyms have been used for C. albicans alone.

Scientists use C. albicans as a model organism to study fungal pathogens. Its genome has been completely sequenced. This makes it one of the first fungi to be fully mapped. The diploid genome size is approximately 29 Mb. The haploid genome size is about 16 Mb. The genome consists of eight sets of chromosome pairs. These are labeled chr1A through chr8A and chr1B through chr8B. There are 6,198 open reading frames in the genome. Remarkably, up to 70% of the protein coding genes have not been characterized.

The genome of C. albicans is highly dynamic. It features high heterozygosity. This diversity comes from chromosomal rearrangements. These include translocations, deletions, and trisomy of individual chromosomes. This variability is an adaptation strategy. An unusual feature is the CUG codon. In most organisms, this codon specifies leucine. In C. albicans, it specifies serine. This departure from the standard genetic code might induce a permanent stress response. This could help the species survive in different environments.

Candidiasis can be very dangerous. Systemic candidiasis has a reported mortality rate of 40%. In the United States, invasive candidiasis in hospitals causes 2,800 to 11,200 deaths every year. Several species are responsible for most human cases. C. albicans, C. tropicalis, C. parapsilosis, and C. glabrata account for 50% to 90% of all cases. Researchers use tools like CHROMagar Candida to identify these different species. Studying these mechanisms helps scientists understand how pathogens interact with human hosts.