Eukaryotes Genomes - CANDIDA GLABRATA

Candida glabrata, previously classified as Torulopsis glabrata , is a yeast that forms part of the normal microbial flora of the mouth gastrointestinal tract, skin, vagina, and stool and can affect people of any age. It is found in the environment, particularly on leaves, flowers, water, and soil. Candida glabrata colonies are small, pasty, white to cream in colour and glistening.

Candida glabrata has emerged as one of the most common causes of candidiasis (candidosis). Candidiasis can range from superficial disorders such as nappy rash to invasive, rapidly fatal infections in immunocompromised hosts. Candida albicans is most commonly responsible for candidiasis, however C. glabrata currently ranks second or third as the causative agent of superficial (oral, esophageal, vaginal, or urinary) or systemic candidal infections worldwide. Males and females are affected equally by most forms of Candida species. In women, candidal infection is the second most common cause of vaginitis and in either sex, chronic yeast infections, caused by Candida species, are common first symptoms of HIV infection. In adults, oral candidiasis increases in incidence with age, the elderly being affected most and gastrointestinal (GI) candidiasis also increases in incidence with age.

Until recently, Candida glabrata was considered a relatively nonpathogenic fungal organism, however, with the increased use of immunosuppressive agents, mucosal and systemic infections caused by C. glabrata have increased significantly, especially in the human immunodeficiency virus-infected population. A major obstacle in C. glabrata infections is their innate resistance to azole antimycotic therapy, which is very effective in treating infections caused by other Candida species. Candida glabrata, contrasts with other Candida species in its nondimorphic blastoconidial morphology. Currently, however, there are few recognised virulence factors of C. glabrata and little is known about the host defense mechanisms that protect against infection. Most candidal infections are superficial and are associated with a benign course and full recovery. However, in immunocompromised hosts, systemic illness is associated with death in as many as 77%.

The organism was sequenced as part of a study that compared five species of yeast. Identifying the mechanisms of eukaryotic genome evolution by comparative genomics is often complicated by the multiplicity of events that have taken place throughout the history of individual lineages, leaving only distorted and superimposed traces in the genome of each living organism. The hemiascomycete yeasts, with their compact genomes, similar lifestyle and distinct sexual and physiological properties, provide a unique opportunity to explore such mechanisms. Analysis of chromosome maps and genome redundancies reveal that the different yeast lineages have evolved through a marked interplay between several distinct molecular mechanisms, including tandem gene repeat formation, segmental duplication, a massive genome duplication and extensive gene loss.

The genome of Candida glabrata is composed of 13 chromosomes totalling ca. 13.6 Mb.

C. glabrata displays no known sexual cycle, despite the fact that haploid strains of the two distinct mating types are regularly isolated from patients.

References:

http://www.doctorfungus.org/thefungi/Candida_glabrata.htm
http://genopole.pasteur.fr/glabrata/
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/candidiasis_t.htm
http://www.emedicine.com