Penicillium marneffei

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A Microbial Biorealm page on the genus Penicillium marneffei

Classification

Higher order taxa

Domain: Fungi

Phylum: Ascomycota

Class: Eurotiomycetes

Order: Eurotiales

family: Trichocomaceae

genus: Penicillium

species: marneffei

Species

NCBI: Taxonomy

Penicillium marneffei

Description and significance

Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.

Penicillium marneffei is a unicellular organism with round to oval celled fungus, 4 to 8 micrometers in diameter [1, 4]. These cells can actually divide by cross wall formation within macrophages, or form extracellular elongated cells. The special feature of Penicillium marneffei compared to other penicillia is its thermal dimorphism. This capability to grow as a mycelium at 25 degrees C and as a yeast at 37 degrees C is the organism’s main virulence factor. [1]

The history and mode of transmission of the organism remains unclear. The natural habitat of the fungus and its exact route of transmission have not been described [9]. Soil exposure, often during the rainy season, has been suggested to be a serious risk factor. Also, many isolates from bamboo rats and humans were shown to share identical multi-locus genotypes. These data show that either transmission of P. marneffei can occur from rodents to humans or rodents and humans are coinfected from common environmental sources. The main route of infection is thought to be through inhalation of conidia into the lungs, where it can then disseminate via a hematogenous route to other body locations, especially the liver. [1]

Penicillium marneffei is a rising pathogenic fungus that can cause a fatal systemic mycosis in patients infected with human immunodeficiency virus (HIV). P. marneffei infection is endemic in tropical Asia, especially Thailand, northeastern India, China, Hong Kong, Vietnam, and Taiwan. It was first isolated from the hepatic lesions of a bamboo rat (Rhizomys sinensis) that had been maintained in captivity for experimental infections at the Pasteur Institute of Indochina, Dalat, South Vietnam, in 1956. The fungus was named Penicillium marneffei, in honor of Hubert Merneffe, who was the director of the Pasteur Institute of Indochina [1]. After discovery of the infection in wild rodents, two cases of human infections were reported. The first case was laboratory acquired. The second, the first known natural human infection, was reported in 1973 [10]. The mortality rate of patients with P. marneffei infection has been extremely high. [1]

Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?

Penicillium marneffei is believed to be haploid, with at least six large chromosomes [5]. The genome size of P. marneffei has been estimated to be in the range of 17.8 to 26.2 Mb [1]. This 35 kb mitochondrial genome contains the genes encoding ATP synthase subunits, cytochrome oxidase subunits, apocytochrome b, reduced nicotinamide adenine dinucleotide ubiquinone oxireductase subunits, ribosomal protein of the small ribosomal subunit, 28 tRNAs, and large ribosomal RNAs [3]. The mitochondrial genome of P. marneffei is more closely related to those of molds than to those of yeasts [1].

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.

Penicillium marneffei is a round-shaped fungus. The distinctive central transverse septum, by the process of fission, is special to P. marneffei. Also, budding and cysts forms are absent in P. marneffei infection [6].

Fungal cell types can be categorized into one of two groups; those that show polarized apical growth and those that exhibit isotrophic growth. A dimorphic fungi is able to switch between these two types. Dimorphic switching requires fungal cells to undergo changes in polarized growth in response to environmental stimuli and during cell differentiation [2]. Penicillium marneffei, an opportunistic human fungal, is the only known Penicillium species that shows temperature-dependent dimorphic growth [1].

When the temperature is below 25, the fungus growth is as multinucleate mycelia with the formation of septate, and branched hyphae. They are also capable of undergoing asexual reproduction, producing uninucleate spores on complex multicullular structures called conidiophores. The 25-37C temperature shift activates the arthroconidiation programme, where cell and nuclear division become coupled, double septa are deposited between hyphal cells and cell separation occurs along the septal plane to free singal yeast cells. When the temperature is at 37 on aritificial medium or in human tissue, the fungus grows in a yeast-like form with the formation of fission arthroconidium cells, where the cell divides by fission to make two uninucleate cells. The germinated conidia produce hyphae that are usually shorter in length and wider in diameter than those produced at 25C. Also, at 37C, the hyphae are more highly branched than at 25C. The fission yeast cells signify the parasitic form of P. marneffei. This mold to yeast change or phase transition is a diagnostic characteristic of P. marneffei. On the contrary, when switching yeast from 37C to 25C, yeast cells elongate, cell and nuclear division uncouple to form multinucleate compartments and grow with a filamentous pattern [1, 2].

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

The basic ecology of this pathogen remains enigmatic. The main issue is whether the human disease, penicilliosis marneffei, occurs as a consequence of animal or environmental transmission. In other words, the ecological reservoir(s) of human peniciliiosis marneffei remains unknown [1].

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

1. Vanittanakom N, Cooper CR Jr, Fisher MC, Sirisanthana T. “Penicillium marneffei infection and and recent advances in the epidemiology and molecular biology aspect.” Clinical Microbiology Reviews (2006) -2006 January; 19(1): 95–110. - http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=16418525

2. Boyce KJ, Hynes MJ, Andrianopoulos A. "The Ras and Rho GTPases genetically interact to co-ordinately regulate cell polarity during development in Penicillium marneffei." Molecular Microbiology (2005) - Volume 55 Issue 5 Page 1487-1501, March 2005 - http://www.blackwell-synergy.com/coi/abs/10.1111/j.1365-2958.2005.04485.x

3. Woo PC, Zhen H, Cai JJ, Yu J, Lau SK, Wang J, Teng JL, Wong SS, Tse RH, Chen R, Yang H, Liu B, Yuen KY. "The mitochondrial genome of the thermal dimorphic fungus Penicillium marneffei is more closely related to molds than yeasts." FEBS Letters (2003) - Volume 555, Issue 3, 18 December 2003, Pages 469-477 - http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T36-4B22RX3-3&_user=10&_coverDate=12%2F18%2F2003&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=bc1887cf249b2ffde64a86d69b05628d

4. Lasker BA. "Nucleotide sequence-based analysis for determining the molecular epidemiology of Penicillium marneffei." Journal of Clinical Microbiology (2006) - September 2006, pg. 3145-3153, Vol. 44, No. 9- http://jcm.asm.org/cgi/content/full/44/9/3145?view=long&pmid=16954240

5. Lasker BA, Ran Y. "Analysis of polymorphic microsatellite markers for typing Penicillium marneffei isolates." Journal of Clinical Microbiology (2004) - April 2004, pg. 1483-1490, Vol. 42, no. 4 - http://jcm.asm.org/cgi/content/full/42/4/1483?view=long&pmid=1570993

6. Lim D, Lee YS, Chang AR. "Rapid Diagnosis of Penicillium marneffei infection by fine needle aspiration cytology." Journal of Clinical Pathology (2006) 59:443-444 - http:jcp.bmj.com/cgi/content/full/59/4/443

7. Cánovas D, Andrianopoulos A. "Developmental Regulation of the glyoxylate cycle in the human pathogen Penicillium marneffei." Molecular microbiology (2006) -Volume 62 Issue 6 Page 1725-1738, December 2006 - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2958.2006.05477.x

8. Liu H, Xi L, Zhang J, Li X, Liu X, Lu C, Sun J. "Identifying differentially expressed genes in the dimorphic fungus Penicillium marneffei by suppression subtraction hybridization." FEMS Microbiology Letters (2007) -Volume 270 Issue 1 Page 97-103, May 2007 -http://www.blackwell-synergy.com/doi/abs/10.1111/j.1574-6968.2007.00652.x

9. Yuen KY, Pascal G, Wong SS, Glaser P, Woo PC, Kunst F, Cai JJ, Cheung EY, Medigue C, Danchin A. "Exploring the Penicillium marneffei genome." Archives of Microbiology (2003) volume 179, Number 5 / May, 2003 - http://www.springerlink.com/content/x9q965haa71c7c9v/

10. Prariyachatigul C, Chaiprasert A, Geenkajorn K, Kappe R, Chuchottaworn C, Termsetjaroen S, Srimuang S. "Development and evaluation of a one-tube seminested PCR assay for the detection and identification of Penicillium marneffei." Mycoses (2003) Volume 46 Issue 11-12, pg. 447-454, December 2003 - http://www.blackwell-synergy.com/doi/abs/10.1046/j.0933-7407.2003.00939.x

11. Supparatpinyo K, Schlamm H. "Voriconazole as Therapy for Systemic Penicillium marneffei Infections in AIDS patients." Tropical Medicine and Hygiene (2007) 77(2), pg. 350-353 - http://www.ajtmh.org/cgi/content/full/77/2/350

12. Thirach S, Cooper Jr. C, Vanittanakom P, Vanittanakom N. "The Copper, Zinc Superoxide Dismutase gene of Penicillium marneffei: Cloning, characterization, and differential expression during phase transition and macrophage infection." Medical Mycology (2007) Volume 45, issue 5 August 2007, pg. 409-417 - http://www.informaworld.com/smpp/section?content=10.1080/13693780701381271

13. Penicillium marneffei, genus NCBI reference: http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=37727&lvl=3&p=mapview&p=has_linkout&p=blast_url&p=genome_blast&lin=f&keep=1&srchmode=1&unlock

Edited by Tiffanie Chan, student of Rachel Larsen