Candida albicans
From DrugPedia: A Wikipedia for Drug discovery
Candida albicans
Candida albicans is a diploid fungus (a form of yeast) and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections (fungemias) have emerged as important causes of morbidity and mortality in immunocompromised patients (e.g., AIDS, cancer chemotherapy, organ or bone marrow transplantation). C. albicans biofilms readily form on the surface of implantable medical devices. In addition, hospital-related infections in patients not previously considered at risk (e.g., patients in an intensive care unit) have become a cause of major health concern.
C. albicans is commensal and is among the gut flora, the many organisms that live in the human mouth and gastrointestinal tract. Under normal circumstances, C. albicans lives in 80% of the human population with no harmful effects, although overgrowth results in candidiasis. Candidiasis is often observed in immunocompromised individuals such as HIV-positive patients. Candidiasis also may occur in the blood and in the genital tract. Candidiasis, also known as "thrush", is a common condition, usually easily cured in people who are not immunocompromised. To infect host tissue, the usual unicellular yeast-like form of C. albicans reacts to environmental cues and switches into an invasive, multicellular filamentous forms
| Kingdom | Fungi |
|---|---|
| Phylum | Ascomycota |
| Class | Saccharomycetes |
| Order | Saccharomycetales |
| Family | Saccharomycetaceae |
| Genus | Candida |
| Species | C. albicans |
| Binomial | Candida albicans |
Contents |
Surface Characteristics
The cell wall is essential to nearly every aspect of the biology and pathogenicity of Candida albicans. Lots of new studies are showing that it is a dynamic organelle.The major components of the cell wall are glucan and chitin, which are associated with structural rigidity, and mannoproteins. Glucans are a heterogeneous group of glucose polymers, consisting of a backbone of β(1-->3)-linked β-D-glucopyranosyl units with β(1-->6)-linked side chains of varying distribution and length. Wall proteins might differ in their secretion, or topological location within the wall structure.Expression of some proteins is associated with the morphological growth form of the fungus and may play a role in morphogenesis.Surface mannoproteins are strong immunogens that trigger and modulate the host immune response during candidiasis. Metabolism: Candida albicans contains two APSES proteins:the regulator Efg1p and its homologue Efh1p.Overexpression of both of these two will result in the similar phenotype(the white to opaque switching as we mentioned before). The result of deleting efh1 was no phenotype under normal condition. On the other hand,it casued hyperfilamentation under hypoxic conditions.
Efg1p not only regulates genes involved in morphogenesis but also strongly influences the expression of metabolic genes, inducing glycolytic genes and repressing genes essential for oxidative metabolism.The result of the experiments show that Efh1p is an activator of gene expression.Also the same experiment supports that Efh1p supports the regulatory functions of the primary regulator, Efg1p, and indicate a dual role for these APSES proteins in the regulation of fungal morphogenesis and metabolism.
Pathogenic Activity
C. albicans have a preference to live in moist,dark and warm enviornment, with a pH of 4.0 to 5.0(acidic)They are one of the gut flora(living in gastroontestinal tract). they also live in human mouth and under normal condition, they live in 80% of human population with no harmful effect.They also appear on mocus and vagina membrane.They can also appear in blood and genital tract.In some cases they have symbiotic relationship with their host and in some other, they wont. There are some major interactions that C. albicans are involved in.They have done a study of Cellular and Molecular biology of C. albicans Estrogen response. During the experiment,exposure to estrogens did not significantly change the biomass of any C. albicans culture tested.The cell bio and gene expression from this study lead to a model that proposes how components of the phospholipid and sterol metabolic pathways may interact to affect C. albicans germ tube formation and length..
Virulence
C. albicans are responsible for different infections.Infections caused by Candida species have substantially increased in incidence over the past 2 decades.
Researchs show that Candida albican is the most common etiological agent of vaginal candidiasis.As in vaginal candidiasis or thrush, the main symptom of which is intense itching.(General term for an infection is candidiasis,but it may vary depends on the type of infection and also region of the body).
When the balance between bacteria and yeast is upset,small colonies of candida can caused yeast infection in humans.It is estimated that more than half of women and men host C. albicans and also around 75% of women will have an episode of vulvo-vaginal candidiases at least once in theier life.
Infants can also be a victim of C. albicans.They may develope yeast infection as an adjusting to diaper rash.(1) Also there are nail infections in humans caused by Candida albicans.To cure that infection, they were using Terbinafine(this drug is active in response to some pathogenic fungi such as molds,dimorphic fungi, and some yeasts)but studies show that drug had little activity against Candida albicans.
Mucocutaneous candidiasis caused by C. albicans is a comon cause of HIV in humans. Most common symptons of disease casued by C. albicans are:
-gastrointestinal and urinary tract disorders
-allergic reactions
-mental and emotional disturbances
-endocrine system compromise
