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Fungal adhesins are proteins located on the surface of fungal cells, specifically found on the outside of the cell wall. [1] They allow fungi to colonize various substrates and to bind to host tissues. Adhesion to tissue is an obligatory first step in pathogenesis by many yeasts. Adhesins also have other functions, such as mating and biofilm formation. [2]
Candida albicans can cause opportunistic oral and genital infections in humans.
Hwp1 is a fungal adhesin belonging to the opportunistic dimorphic fungus Candida albicans. Hwp1 is unique among fungal adhesins discovered to date in that it is a mammalian transglutaminase substrate. The host enzyme allows C. albicans to form covalent bonds to the host tissue via Hwp1. [3]
Candidiasis is a fungal infection due to any type of Candida. When it affects the mouth, in some countries it is commonly called thrush. Signs and symptoms include white patches on the tongue or other areas of the mouth and throat. Other symptoms may include soreness and problems swallowing. When it affects the vagina, it may be referred to as a yeast infection or thrush. Signs and symptoms include genital itching, burning, and sometimes a white "cottage cheese-like" discharge from the vagina. Yeast infections of the penis are less common and typically present with an itchy rash. Very rarely, yeast infections may become invasive, spreading to other parts of the body. This may result in fevers along with other symptoms depending on the parts involved.
Candida albicans is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is usually a commensal organism, but it can become pathogenic in immunocompromised individuals under a variety of conditions. It is one of the few species of the genus Candida that causes the human infection candidiasis, which results from an overgrowth of the fungus. Candidiasis is, for example, often observed in HIV-infected patients. C. albicans is the most common fungal species isolated from biofilms either formed on (permanent) implanted medical devices or on human tissue. C. albicans, C. tropicalis, C. parapsilosis, and C. glabrata are together responsible for 50–90% of all cases of candidiasis in humans. A mortality rate of 40% has been reported for patients with systemic candidiasis due to C. albicans. By one estimate, invasive candidiasis contracted in a hospital causes 2,800 to 11,200 deaths yearly in the US. Nevertheless, these numbers may not truly reflect the true extent of damage this organism causes, given new studies indicating that C. albicans can cross the blood brain barrier.
Candida is a genus of yeasts and is the most common cause of fungal infections worldwide. Many species are harmless commensals or endosymbionts of hosts including humans; however, when mucosal barriers are disrupted or the immune system is compromised they can invade and cause disease, known as an opportunistic infection. Candida is located on most of mucosal surfaces and mainly the gastrointestinal tract, along with the skin. Candida albicans is the most commonly isolated species and can cause infections in humans and other animals. In winemaking, some species of Candida can potentially spoil wines.
Oral candidiasis, also known as oral thrush among other names, is candidiasis that occurs in the mouth. That is, oral candidiasis is a mycosis of Candida species on the mucous membranes of the mouth.
Phenotypic switching is switching between multiple cellular morphologies. David R. Soll described two such systems: the first high frequency switching system between several morphological stages and a second high frequency switching system between opaque and white cells. The latter is an epigenetic switching system
Adhesins are cell-surface components or appendages of bacteria that facilitate adhesion or adherence to other cells or to surfaces, usually in the host they are infecting or living in. Adhesins are a type of virulence factor.
Candida parapsilosis is a fungal species of yeast that has become a significant cause of sepsis and of wound and tissue infections in immunocompromised people. Unlike Candida albicans and Candida tropicalis, C. parapsilosis is not an obligate human pathogen, having been isolated from nonhuman sources such as domestic animals, insects and soil. C. parapsilosis is also a normal human commensal and it is one of the fungi most frequently isolated from human hands. There are several risk factors that can contribute to C. parapsilosis colonization. Immunocompromised individuals and surgical patients, particularly those undergoing surgery of the gastrointestinal tract, are at high risk for infection with C. parapsilosis. There is currently no consensus on the treatment of invasive candidiasis caused by C. parapsilosis, although the therapeutic approach typically includes the removal of foreign bodies such as implanted prostheses and the administration of systemic antifungal therapy. Amphotericin B and Fluconazole are often used in the treatment of C. parapsilosis infection.
Candida glabrata is a species of haploid yeast of the genus Candida, previously known as Torulopsis glabrata. Despite the fact that no sexual life cycle has been documented for this species, C. glabrata strains of both mating types are commonly found. C. glabrata is generally a commensal of human mucosal tissues, but in today's era of wider human immunodeficiency from various causes, C. glabrata is often the second or third most common cause of candidiasis as an opportunistic pathogen. Infections caused by C. glabrata can affect the urogenital tract or even cause systemic infections by entrance of the fungal cells in the bloodstream (Candidemia), especially prevalent in immunocompromised patients.
Dimorphic fungi are fungi that can exist in the form of both mold and yeast. This is usually brought about by change in temperature and the fungi are also described as thermally dimorphic fungi. An example is Talaromyces marneffei, a human pathogen that grows as a mold at room temperature, and as a yeast at human body temperature.
In enzymology, a sterol 14-demethylase (EC 1.14.13.70) is an enzyme that catalyzes the chemical reaction
Pathogenic fungi are fungi that cause disease in humans or other organisms. Approximately 300 fungi are known to be pathogenic to humans. The study of fungi pathogenic to humans is called "medical mycology". Although fungi are eukaryotic, many pathogenic fungi are microorganisms. The study of fungi and other organisms pathogenic to plants is called plant pathology.
Fibronectin binding protein A (FnBPA) is a Staphylococcus aureus MSCRAMM cell surface-bound protein that binds to both fibronectin and fibrinogen.
Histatins are histidine-rich (cationic) antimicrobial proteins found in saliva. Histatin's involvement in antimicrobial activities makes histatin part of the innate immune system.
Lorena Beese is a James B. Duke Professor of Biochemistry at Duke University. She received her PhD in Biophysics from Brandeis University and did her postdoctoral work with Dr. Thomas A. Steitz at Yale University. In 2009 Dr. Beese was elected to the National Academy of Sciences.
Hwp1 is a protein (glycoprotein) located on the surface of an opportunistic diploid fungus called Candida albicans.
C-5 sterol desaturase is an enzyme that is highly conserved among eukaryotes and catalyzes the dehydrogenation of a C-5(6) bond in a sterol intermediate compound as a step in the biosynthesis of major sterols. The precise structure of the enzyme’s substrate varies by species. For example, the human C-5 sterol desaturase oxidizes lathosterol, while its ortholog ERG3 in the yeast Saccharomyces cerevisiae oxidizes episterol.
Vomocytosis is the cellular process by which live organisms that have previously been engulfed by a white blood cell are expelled without being destroyed. Vomocytosis was first reported in 2006 by two groups, working simultaneously in the UK and the USA, based on time-lapse microscopy footage characterising the interaction between macrophages and the human fungal pathogen Cryptococcus neoformans. Subsequently, this process has also been seen with other fungal pathogens such as Candida albicans and Candida krusei. It has also been speculated that the process may be related to the expulsion of bacterial pathogens such as Mycobacterium marinum from host cells. Vomocytosis has been observed in phagocytic cells from mice, humans and birds, as well as being directly observed in zebrafish and indirectly detected in mice. Amoebae exhibit a similar process to vomocytosis whereby phagosomal material that cannot be digested is exocytosed. Cryptococci are exocytosed from amoebae via this mechanism but inhibition of the constitutive pathway demonstrated that cryptococci could also be expelled via vomocytosis.
Candidalysin is a cytolytic 31-amino acid α-helical amphipathic peptide toxin found in the opportunistic pathogen Candida albicans that activates epithelial cells. As such, Candidalysin is a rare fungal example of a classical virulence factor. Hyphal morphogenesis in C. albicans is associated with damage to host epithelial cells; during this process Candidalysin is released. Candidalysin promotes damage of oral epithelial cells by inducing lactate dehydrogenase release and calcium ion influx. It is unique in the fact that it is the first peptide toxin to be identified in any human fungal pathogen.
Candida tropicalis is a species of yeast in the genus Candida. It is a common pathogen in neutropenic hosts, in whom it may spread through the bloodstream to peripheral organs. For invasive disease, treatments include amphotericin B, echinocandins, or extended-spectrum triazole antifungals.
Carol Kumamoto is an American microbiologist who is Professor of Molecular Biology & Microbiology at Tufts University. She investigates the filamentous growth of Candida albicans, a fungal pathogen that causes several diseases. She is also interested in how C. albicans interacts with its host during colonisation and invasive diseases. She is a Fellow of the American Association for the Advancement of Science and the American Society for Microbiology.
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