| Candida albicans | ||||||||||||||||
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| Candida albicans (C. P. Robin) Berkhout 1923 | ||||||||||||||||
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Candida stellatoidea[1] Oidium albicans[2] |
Candida albicans is a diploid fungus (a form of yeast), which is capable of mating but not of meiosis, and a causal agent of opportunistic oral and genital infections in humans. Christine Marie Berkhout (1893–1932 was a Mycologist. She described the genus Candida in her Doctoral thesis for the University of Utrecht In Scientific nomenclature, synonyms are different Scientific names used for a single Taxon. "Haplo" redirects here For the fictional character see The Death Gate Cycle. A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Yeasts are a growth form of eukaryotic Microorganisms classified in the kingdom Fungi, with about 1500 Species currently described An opportunistic infection is an infection caused by Pathogens that usually do not cause disease in a healthy Immune system. A sex organ, or primary sexual characteristic, as narrowly defined is any of the anatomical parts of the body which are involved in sexual reproduction and constitute [3][4] Systemic fungal infections (fungemias) have emerged as important causes of morbidity and mortality in immunocompromised patients (e. Fungemia (also known as Candidemia, Candedemia, and Invasive Candidiasis) is the presence of fungi or Yeasts in the Blood In Medicine, Epidemiology and Actuarial science, the term morbidity can refer to the state of poor health (from Latin Death is the termination of the biological functions that define living Organisms It refers both to a specific In Medicine, immunodeficiency (or immune deficiency) is a state in which the Immune system 's ability to fight Infectious disease is compromised g. , AIDS, cancer chemotherapy, organ or bone marrow transplantation). Chemotherapy, in its most general sense refers to treatment of disease by chemicals that kill cells specifically those of micro-organisms or Cancer. Bone marrow is the flexible tissue found in the hollow interior of Bones In adults marrow in large bones produces new Blood cells It constitutes 4% of 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 among the gut flora, the many organisms which live in the human mouth and gastrointestinal tract. The gut flora are the Microorganisms that normally live in the Digestive tract and can perform a number of useful functions for their hosts Under normal circumstances, C. albicans lives in 80% of the human population with no harmful effects, although overgrowth results in candidiasis. Candidiasis, commonly called yeast infection or thrush, is a Fungal infection (mycosis of any of the Candida species of which Candidiasis is often observed in immunocompromised individuals such as HIV-positive patients. In Medicine, immunodeficiency (or immune deficiency) is a state in which the Immune system 's ability to fight Infectious disease is compromised Human immunodeficiency virus ( HIV) is a Lentivirus (a member of the Retrovirus family that can lead to acquired immunodeficiency syndrome Candidiasis also may occur in the blood and in the genital tract. Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells €”such as nutrients and oxygen—and transports Waste products A sex organ, or primary sexual characteristic, as narrowly defined is any of the anatomical parts of the body which are involved in sexual reproduction and constitute Candidiasis, also known as "thrush", is a common condition which is usually easily cured in people who are not immunocompromised. To infect host tissue, the usual unicellular yeast-like form of Candida albicans reacts to environmental cues and switches into an invasive, multicellular filamentous forms. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually Yeasts are a growth form of eukaryotic Microorganisms classified in the kingdom Fungi, with about 1500 Species currently described [3]
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Genome
One of the most interesting features of the C. albicans genome is the occurrence of numeric and structural chromosomal rearrangements as means of generating genetic diversity, named chromosome length polymorphisms (contraction/expansion of repeats), reciprocal translocations, chromosome deletions and trisomy of individual chromosomes. A chromosome is an organized structure of DNA and Protein that is found in cells. In Genetics, a chromosome translocation is a Chromosome abnormality caused by rearrangement of parts between nonhomologous Chromosomes. In Genetics, a deletion (also called gene deletion, deficiency, or deletion mutation) is a Mutation (a genetic aberration A trisomy is a form of Aneuploidy with the presence of three copies instead of the normal two of a particular Chromosome. These karyotypic alterations lead to changes in the phenotype, which is an adaptation strategy of this fungus. A karyotype is the characteristic Chromosome complement of a Eukaryote Species. An adaptation is a characteristic of an Organism that has been favored by Natural selection and These mechanisms will be better understood with the complete analysis of the C. albicans genome.
The Candida albicans genome for strain SC5314 was sequenced at the Stanford DNA Sequencing and Technology Center. The term DNA sequencing encompasses biochemical methods for determining the order of the Nucleotide bases Adenine, Guanine, Cytosine [5][6] The genome of the WO1 strain was sequenced by the Broad Institute of MIT and Harvard. The Broad Institute of MIT and Harvard is an American research institute dedicated to the study of Genomics for the biomedical sciences [7]
The sequencing of the C. albicans genome and subsequently of the genomes of several other medically relevant Candida species has profoundly and irreversibly changed the way Candida species are now investigated and understood. [4] The C. albicans genome sequencing effort was launched in October 1996. Successive releases of the sequencing data and genome assemblies have marked the last 10 years, culminating with the release of the diploid assembly 19 which provided a haploid version of the genome along with data on allelic regions in the genome. [4] A refined assembly 20 with the eight assembled C. albicans chromosomes was released in the summer of 2006. Importantly, the availability of sequencing data prior to the completion of the genome sequence has made it possible to start C. albicans post-genomics early on. In this regard, genome databases have been made available to the research community providing different forms of genome annotation. These have been merged in a community-based annotation hosted by the Candida Genome Database. The availability of the genome sequence has paved the way for the implementation of post-genomic approaches to the study of C. albicans: macroarrays and then microarrays have been developed and used to study the C. albicans transcriptome; proteomics has also been developed and complements transcriptional analyses; furthermore, systematic approaches are becoming available to study the contribution of each C. albicans gene in different contexts. Other Candida genome sequences have been, or are being, determined: C. glabrata, C. dubliniensis, C. parapsilosis, C. guilliermondii, C. lusitaniae, and C. tropicalis. These species will soon enter the post-genomic era as well and provide interesting comparative data. The genome sequences obtained for the different Candida species along with those of non-pathogenic hemiascomycetes provide a wealth of knowledge on the evolutionary processes which have shaped the hemiascomycete group as well as those which may have contributed to the success of different Candida species as pathogens. [4]
The genome of C. albicans is highly dynamic and this variability has been used advantageously for molecular epidemiological studies of C. albicans and population studies in this species. A remarkable discovery which has arisen from the genome sequence is the presence of a parasexual cycle in C. albicans. This parasexual cycle is under the control of mating-type loci and switching between white and opaque phenotypes. Investigating the role which the mating process plays in the dynamics of the C. albicans population or in other aspects of C. albicans biology and pathogenicity will undoubtedly represent an important focus for future research. [4]
Dimorphism
In a process which superficially resembles dimorphism, C. Sexual dimorphism is the systematic difference in form between individuals of different Sex in the same Species. albicans undergoes a process called phenotypic switching, in which different cellular morphologies are generated spontaneously. Phenotypic switching (aka phenotypic dimorphism is switching between two cell-types One of the classically studied strains which undergoes phenotypic switching is WO-1, which consists of two phases - one which grows as smooth white colonies and one which is rod-like and grows as flat gray colonies. The other strain known to undergo switching is 3153A; this strain produces at least seven different colony morphologies. In both the WO-1 and 3153A strains, the different phases convert spontaneously to the other(s) at a low frequency. The switching is reversible, and colony type can be inherited from one generation to another. While several genes which are expressed differently in different colony morphologies have been identified, some recent efforts have focused on what might be controlling these changes. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance Gene expression is the process by which inheritable information from a Gene, such as the DNA sequence, is made into a functional Gene product, such Further, whether there is a potential molecular link between dimorphism and phenotypic switching is a tantalizing question.
In the 3153A strain, a gene called SIR2 (for silent information regulator) has been found which seems to be important for phenotypic switching. SIR2 was originally found in Saccharomyces cerevisiae (brewer's yeast), where it is involved in chromosomal silencing — a form of transcriptional regulation in which regions of the genome are reversibly inactivated by changes in chromatin structure (chromatin is the complex of DNA and proteins which make chromosomes). Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times Gene silencing is a general term describing Epigenetic processes of Gene regulation. Transcriptional regulation is the change in gene expression levels by altering transcription rates In classical genetics the genome of a Diploid Organism including Eukarya refers to a full set of chromosomes or genes in a Gamete, thereby Chromatin is the complex basis of DNA and protein that makes up Chromosomes It is found inside the nuclei of eukaryotic cells, and within the Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known A chromosome is an organized structure of DNA and Protein that is found in cells. In yeast, genes involved in the control of mating type are found in these silent regions, and SIR2 represses their expression by maintaining a silent-competent chromatin structure in this region. The discovery of a C. albicans SIR2 which is implicated in phenotypic switching suggests that it too has silent regions controlled by SIR2, in which the phenotype-specific genes may perhaps reside.
Another potential regulatory molecule is Efg1p, a transcription factor found in the WO-1 strain which regulates dimorphism, and more recently has been suggested to help regulate phenotypic switching. In the field of Molecular biology, a transcription factor (sometimes called a sequence-specific DNA binding factor is a Protein that binds to specific sequences Efg1p is expressed only in the white and not in the gray cell-type, and overexpression of Efg1p in the gray form causes a rapid conversion to the white form.
So far there are few data which say that dimorphism and phenotypic switching use common molecular components. However, it is not inconceivable that phenotypic switching may occur in response to some change in the environment as well as being a spontaneous event. How SIR2 itself is regulated in Saccharomyces cerevisiae may yet provide clues as to the switching mechanisms of C. Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times albicans.
Heterozygosity
The heterozygosity of the Candida genome exceeds that found in other genomes and is widespread among clinical isolates. Zygosity refers to the genetic condition of a Zygote. In genetics zygosity describes the similarity or dissimilarity of DNA between Homologous Non-synonymous single base polymorphisms result in two proteins that differ in one or several amino acids that may confer functional differences for each protein. A single nucleotide polymorphism ( SNP, pronounced snip) is a DNA sequence variation occurring when a single Nucleotide - A, T This situation considerably increases the number of different proteins encoded by the genome. [8]
See also
- Torula yeast (Candida utilis)
- Undecylenic acid (Castor oil derivative) for candida fungus infections. Torula (Latin name Candida utilis; formerly Torulopsis utilis, Torula utilis) is a species of Yeast. Undecylenic / Undecenoic Acid is an organic unsaturated Fatty acid derived from natural Castor oil.
- Leaky gut syndrome for damage to the bowel or gut (increased permeability to gut wall or bowel lining). Leaky gut syndrome is a diagnosis prevalent in various branches of Alternative medicine.
References
- ^ Candida albicans at NCBI Taxonomy browser, url accessed 2006-12-26
- ^ "Factors Affecting the Morphology of Candida Albicans" Dan Otho McClary Annals of the Missouri Botanical Garden, Vol. 39, No. 2 (May, 1952), pp. 137-164. doi:10. 2307/2394509
- ^ a b Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed. , McGraw Hill. ISBN 0-8385-8529-9.
- ^ a b c d e dEnfert C; Hube B (editors) (2007). Candida: Comparative and Functional Genomics. Caister Academic Press. ISBN 9781904455134.
- ^ Jones T, Federspiel N, Chibana H, Dungan J, Kalman S, Magee B, Newport G, Thorstenson Y, Agabian N, Magee P, Davis R, Scherer S (2004). "The diploid genome sequence of Candida albicans". Proc Natl Acad Sci U S A 101 (19): 7329-34. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 15123810.
- ^ Braun B, van Het Hoog M, d'Enfert C, Martchenko M, Dungan J, Kuo A, Inglis D, Uhl M, Hogues H, Berriman M, Lorenz M, Levitin A, Oberholzer U, Bachewich C, Harcus D, Marcil A, Dignard D, Iouk T, Zito R, Frangeul L, Tekaia F, Rutherford K, Wang E, Munro C, Bates S, Gow N, Hoyer L, K�hler G, Morschh�user J, Newport G, Znaidi S, Raymond M, Turcotte B, Sherlock G, Costanzo M, Ihmels J, Berman J, Sanglard D, Agabian N, Mitchell A, Johnson A, Whiteway M, Nantel A (2005). "A human-curated annotation of the Candida albicans genome". PLoS Genet 1 (1): 36-57. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 16103911.
- ^ Candida albicans Database - Broad Institute
- ^ Larriba G; Calderone RA (2008). "Heterozygosity and Loss of Heterozygosity in Candida albicans", Pathogenic Fungi: Insights in Molecular Biology. Caister Academic Press. ISBN 978-1-904455-32-5.
- Jones et al. 2004. The diploid genome sequence of Candida albicans PNAS 101:7329-7334.
- CandidaDB.a multi-genome database for Candida species and related Saccharomycotina
External links
- Candida Genome Database
- U.S. National Institutes of Health on the Candida albicans genome
- Causes for candida albicans & Natural Herbal Treatment, FAQ. No clinical tests mentioned.
- NIH - How Candida albicans switches phenotype
- Candida albicans genome
- Candida genomics
- Eczema, psoriasis, Chronic Rashes, and their relationship to Candida albicans. Website sells book promoting yeast-free diet. No clinical tests mentioned.
- Incidence of Candida in psoriasis--a study on the fungal flora of psoriatic patients
- Interlocking Transcriptional Feedback Loops Control White-Opaque Switching in Candida albicans
Dictionary
Candida albicans
-proper noun
- (microbiology) A diploid asexual fungus (a form of yeast). An overgrowth results in candidiasis in immunocompromised patients.
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