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11
Tree of Life Project,
http://www.tolweb.org/tree?group=fungi&contgroup=Eukaryotes
Fungi
Meredith Blackwell,
Department of Plant Biology
Louisiana State University
Baton Rouge
Louisiana 70803, USA
Rytas Vilgalys
http://www.biology.duke.edu/fungi/mycolab/
Department of Botany
Duke University
Durham, NC 27708-0338
USA
and,
John Taylor
Department of Plant and Microbial Biology
111 Koshland Hall
University of California
Berkeley, CA 94720-3120
USA
The organisms of the fungal lineage include mushrooms, rusts, smuts, puffballs, truffles, morels, molds, and yeasts, as well as many less well-known organisms (Alexopoulos et al., 1996). About 70,000 species of fungi have been described; however, some estimates of total numbers suggest that 1.5 million species may exist (Hawksworth, 1991; Hawksworth et al., 1995).
As the sister group of animals and part of the eukaryotic crown group that radiated about a billion years ago, the fungi constitute an independent group equal in rank to that of plants and animals. They share with animals the ability to export hydrolytic enzymes that break down biopolymers, which can be absorbed for nutrition. Rather than requiring a stomach to accomplish digestion, fungi live in their own food supply and simply grow into new foodas the local environment becomes nutrient depleted.
Most biologists have seen dense filamentous fungal colonies growing on rich nutrient agar plates, but in nature the filaments can be much longer and the colonies less dense. When one of the filaments contacts a food supply, the entire colony mobilizes and reallocates resources to exploit the new food. Should all food become depleted, sporulation is triggered. Although the fungal filaments and spores are microscopic, the colony can be very large with individuals of some species rivaling the mass of the largest animals or plants. ...
Prior to mating in sexual reproduction, individual fungi communicate with other individuals chemically via pheromones. ... Within their varied natural habitats fungi usually are the primary decomposer organisms present. Many species are free-living saprobes (users of carbon fixed by other organisms) in woody substrates, soils, leaf litter, dead animals, and animal exudates. The large cavities eaten out of living trees by wood-decaying fungi provide nest holes for a variety of animals, ....
... many other fungi are biotrophs, and in this role a number of successful groups form symbiotic associations with plants (including algae), animals (especially arthropods), and prokaryotes. Examples are lichens, mycorrhizae, and leaf and stem endophytes. Although lichens may seem infrequent in polluted cities, they can form the dominant vegetation in nordic environments, and there is a better than 80% chance that any plant you find is mycorrhizal. Leaf and stem endophytes are a more recent discovery, and some of these fungi can protect the plants they inhabit from herbivory and even influence flowering and other aspects of plant reproductive biology.
Fungi are our most important plant pathogens, and include rusts, smuts, and many ascomycetes such as the agents of Dutch elm disease and chestnut blight. Among the other well known associations are fungal parasites of animals. Humans, for example, may succumb to diseases caused by Pneumocystis (a type of pneumonia that affects individuals with supressed immune systems), Coccidioides (valley fever), Ajellomyces (blastomycosis and histoplasmosis), and Cryptococcus (cryptococcosis). ...
Entomophthora, "destroyer of insects", is the agent of a fungual infection that kills flies. After their death the fungal growth erupts through the fly cuticle, and dispersal by forcible spore discharge is a source of inoculum for infection of new flies. ... a number of fungi are used in the processing and flavoring of foods (baker's and brewer's yeasts, Penicillia in cheese-making) and in production of antibiotics and organic acids. Other fungi produce secondary metabolites such as aflatoxins that may be potent toxins and carcinogens in food of birds, fish, humans, and other mammals. ...
Fungi are characterized by non-motile bodies (thalli) constructed of apically elongating walled filaments (hyphae), a life cycle with sexual and asexual reproduction, usually from a common thallus, haploid thalli resulting from zygotic meiosis, and heterotrophic nutrition. Spindle pole bodies, not centrioles, usually are associated with the nuclear envelope during cell division. The characteristic wall components are chitin ... and glucans ....
Certain members of Zygomycota, Ascomycota, and Basidiomycota may lack hyphal growth during part or all of their life cycles, and, instead, produce budding yeast cells. Most fungal species with yeast growth forms contain only minute amounts of chitin in the walls of the yeast cells. ...
Wherever adequate moisture, temperature, and organic substrates are available, fungi are present. Although we normally think of fungi as growing in warm, moist forests, many species occur in habitats that are cold, periodically arid, or otherwise seemingly inhospitable. It is important to recognize that optimum conditions for growth and reproduction vary widely with fungal species. ...
Penicillium chrysogenum is known for its production of the antibiotic penicillin. ... In the past a simple scratch sometimes could produce a fatal infection such as the one that resulted in the death of Tad Lincoln, the son of a U. S. president. However, misuse of penicillin and other antibiotics has resulted in selection of resistant microorganisms, and the threat of untreatable bacterial infections and diseases (for example, tuberculosis and syphilis) has returned. ...
As presently delimited, the kingdom Fungi is believed to constitute a monophyletic group that shares some characters with animals such as chitinous structures, storage of glycogen, and mitochondrial UGA coding for tryptophan. ...
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12
Doctor Fungus.org
Candidiasis: Overview and Full Index
Content Director: Luis Ostrosky-Zeichner, MD.,FACP
... Candida are thin-walled, small yeasts (4 to 6 microns) that reproduce by budding. Even though there are more that 150 species of Candida, no more than ten cause disease in humans with any frequency. Of these, Candida albicans causes almost 100% of cases of oropharyngeal candidiasis and at least 90% of cases of Candida vulvovaginitis. When Candida produce invasive candidiasis, the other species of Candida begin to be seen with increased frequency. ...
Candida spp. can be found in soil, inanimate objects, food, and hospital environments.
Asymptomatic colonization:
Candida spp. are normal commensals of man and can be recovered from many sources in normal and ill individuals. However, Candida spp. can also produce a wide variety of infections, and distinguishing between colonization and infection can sometimes be a challenge. Even though diseases related to Candida have been known for centuries, the importance of these conditions has assumed increased relevance during the last two decades.
A dramatic change in the epidemiology of infectious diseases has taken place with the advent of new chemotherapeutic agents, new immunosuppressive agents, organ transplantation, parenteral alimentation, broad-spectrum antibiotics, and advanced surgical techniques. In this new scenario, fungal infections have emerged as a critical issue in the compromised host. Among these, Candida spp. are the most common fungal pathogens.
Candida spp. are also competing with the bacteria as one of the leading causes of nosocomial infections. In addition, the ability of Candida spp. to produce oropharyngeal candidiasis in patients with HIV-AIDS has made candidiasis the leading fungal infection in this immunosuppressed population.
Candida spp. can both colonize (be present without causing disease) or infect any body surface. "Mucosa" refers to those body surfaces that are adapted to continuous or near-continuous exposure to moisture. ...
"Invasive" implies invasion past the skin.
Also called systemic candidiasis, invasive candidiasis is a complicated collection of diseases. These forms of candidiasis are only seen in individuals with reduced function of the immune system or some other type of weakening of their defenses. Almost any organ of the body may be involved.
General Diagnostic Strategies
The diagnosis of almost any form of Candida disease requires an integration of clinical, epidemiological, and laboratory findings. The isolation of Candida from wounds, skin, urine, sputum, or stool specimens is not diagnostic of disease. On the other hand, growth of Candida spp. from sterile specimens (e.g., blood or CSF) is almost always diagnostic of infection. ....
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Doctor Fungus.org
Candida: Species
Content Director: Luis Ostrosky-Zeichner, MD.,FACP
(described by Bennett in 1844)
Taxonomic classification
Kingdom: Fungi
Phylum: Ascomycota
Subphylum: Ascomycotina
Class: Ascomycetes
Order: Saccharomycetales
Family: Saccharomycetaceae
Genus: Candida
Candida albicans, Candida castellani, Candida chodatii, Candida ciferrii, Candida claussenii, Candida dubliniensis, Candida famata, Candida famata, Candida fibrae, Candida firmetaria, Candida glabrata, Candida guilliermondii, Candida haemulonii, Candida humicola, Candida javanica, Candida kefyr, Candida krusei, Candida lambica, Candida lipolytica, Candida lodderae, Candida lusitaniae, Candida melibiosi, Candida norvegensis, Candida paralipolytica, Candida parapsilosis, Candida paratropicalis, Candida pelliculosa, Candida pseudotropicalis, Candida robusta, Candida rugosa, Candida salida, Candida sorbosa, Candida stellatoidea, Candida tropicalis, Candida valida, Candida variabilis, Candida vinaria, Candida viswanathii, Candida vulgaris, Candida zeylanoides ....
Description and Natural Habitats
Candida is a yeast and the most common cause of opportunistic mycoses worldwide. It is also a frequent colonizer of human skin and mucous membranes. Candida is a member of normal flora of skin, mouth, vagina, and stool. As well as being a pathogen and a colonizer, it is found in the environment, particularly on leaves, flowers, water, and soil. While most of the Candida spp. are mitosporic, some have known teleomorphic state and produce sexual spores. ...
Species
The genus Candida includes around 154 species. Among these, six are most frequently isolated in human infections. While Candida albicans is the most abundant and significant species, Candida tropicalis, Candida glabrata, Candida parapsilosis, Candida krusei, and Candida lusitaniae are also isolated as causative agents of Candida infections. Importantly, there has been a recent increase in infections due to non-albicans Candida spp., such as Candida glabrata and Candida krusei. ...
... the diversity of Candida spp. that are encountered in infections is expanding and the emergence of other species that were rarely in play in the past is now likely
The clinical spectrum of candidiasis is extremely diverse. Almost any organ or system in the body can be affected. Candidiasis may be superficial and local or deep-seated and disseminated. Disseminated infections arise from hematogenous spread from the primarily infected locus. Candida albicans is the most pathogenic and most commonly encountered species among all. Its ability to adhere to host tissues, produce secretory aspartyl proteases and phospholipase enzymes, and transform from yeast to hyphal phase are the major determinants of its pathogenicity.
PREDISPOSING FACTORS
Physiological: Pregnancy, age (elderly and infancy)
Trauma: Maceration, infection, burn wound
Hematological: Neutropenia, cellular immunodeficiency (leukemia, lymphoma, AIDS, aplastic anemia)
Endocrinological: Diabetes Mellitus, hypoparathyroidism, Addison's disease
Iatrogenic: Chemotherapeutics, corticosteroids, oral contraceptives, antibiotics, catheters, surgery
Other: Intravenous drug addiction, malnutrition, malabsorption, thymoma ...
[heavy metals poisoning, including leaking dental mercury amalgams, contribute to all physiological, hematological and endocrinological symptoms]
Macroscopic and Microscopic Features
The colonies of Candida spp. are cream colored to yellowish, grow rapidly and mature in 3 days. The texture of the colony may be pasty, smooth, glistening or dry, wrinkled and dull, depending on the species. ... Although they are the members of the same genus, the various species do have some degree of unique behavior with respect to their colony texture, microscopic morphology ... and fermentation or assimilation profiles in biochemical tests.
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Doctor Fungus.org
Candida Pneumonia
Content Director: Luis Ostrosky-Zeichner, MD.,FACP
Candida pneumonia is one of the most challenging of all the Candida infections. Rules for a practical and accurate diagnostic approach are elusive. As Candida spp. are frequent asymptomatic colonizers of the upper respiratory tract, especially among hospitalized patients, the predictive value of sputum and even bronchoalveolar cultures for actual candidal lung invasion is very low. In addition, physicians would ideally like to distinguish hematogenous Candida pneumonia related to invasive candidiasis from isolated lung infection. However, in the clinical practice such discrimination is very difficult.
... the lung is always among the three organs most frequently involved in patients who die with invasive candidiasis. ... Clinically, the most common symptoms are fever, tachypnea, dyspnea, and chest pain. Secondary Candida pneumonia will present as part of the complex of symptoms related to the concomitant episode of invasive candidiasis. Pulmonary involvement is usually inapparent. ...
Specific Diagnostic Strategies
Candidal pneumonia is exceedingly difficult to diagnose antemortem. Cultures from either the sputum or bronchoscopic samples (whether quantified or not) are both poor predictors of tissue invasion. ...
Histopathology
The diagnosis of Candida pneumonia can only be solidly established with a histopathologic sample. Expected findings on microscopic examination of cases of primary Candida pneumonia are:
- evidence of aspiration: presence of oropharyngeal elements like food particles and squamous cells lying freely within the bronchi lumen and the alveoli and
- evidence of Candida invasion into the bronchial wall, with or without detached respiratory epithelium.
Classic findings of secondary Candida pneumonia are:
- microabscesses with pseudohyphae penetrating blood vessels (capillaries, arterioles and small arteries), PLUS
- evidence of Candida pseudohyphae invading lung interstitium and airways.
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Doctor Fungus.org
Cardiac Candidiasis
Content Director: Luis Ostrosky-Zeichner, MD.,FACP
Candida are the most frequent fungal agent causing cardiac infection including ... cardiac candidiasis, candida endocarditis, candidal endocarditis, candida pericarditis, candidal pericarditis, candida myocarditis, candidal myocarditis, fungal prosthetic valve endocarditis, fungal endocarditis. ... both in adults and children.
Candidal endocarditis is a severe condition that has been traditionally associated with an exceptional high mortality and recurrence rates. ... Intravenous drug abusers have the highest rates of fungal endocarditis. ... Neonates may develop endocarditis as part of the picture of disseminated neonatal candidiasis. ... Open heart surgery is one of the most frequent risk factors for fungal endocarditis. ... cases without any known risk factor have been reported. ...
The classic signs of bacterial endocarditis have all been described in cases of Candida endocarditis. They include in order of frequency:
- Fever
- Changing murmur
- Splenomegaly
- Peripheral embolism and their related signs
- Congestive heart failure
- Chorioretinitis
- Cutaneous lesions: petechiae, papules, pustules, ulcerative lesions and nodules
... emboli to large vessels in the brain, kidneys, limbs and mesenteric organs, have been classically linked both to fungal endocarditis in general and candidal endocarditis in particular. ... Onset of symptoms can be either insidious or abrupt. ... Candida endocarditis carries a high rate of mortality. Medical treatment alone usually fails. Attempts to treat Candida endocarditis with antifungal agents alone were invariably unsuccessful. ... Indeed, the chronic nature of Candida makes eradication of this infection difficult and long-term antifungal therapy is usually necessary. ...
The majority of cases have a nonspecific clinical picture and the diagnosis is frequently established on post-mortem examination. The physician should be alert and suspect this condition in patients at risk presenting a combination of the following symptoms/signs: fever, increasing cardiac shadow, and pleural effusion.
...
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Doctor Fungus.org
Invasive Candidiasis Overview
Content Director: Luis Ostrosky-Zeichner, MD.,FACP
The term "Invasive Candidiasis" is equivalent to "Disseminated Candidiasis", "Systemic Candidiasis," and "Hematogenous Candidiasis". ... Candida spp. can invade and cause disease in virtually any organ of the body. However, there are many natural barriers to this form of disease, and it only occurs in individuals who have reduced or altered host defenses. ...
No single test is available to make a straightforward diagnosis on invasive candidiasis. Instead, a physician must combine his or her knowledge of the patient's risk factors for invasive candidiasis, clinical signs that might suggest candidiasis, and a variety of possible bits of laboratory data. ...
Candida spp. grow easily when present in biopsy specimens, aspirates, or surface cultures of involved sites. Only 1 to 3 days are necessary to grow C. albicans, C. parapsilosis and C. tropicalis on any standard medium, while growth of C. krusei and C. glabrata may take slightly longer. ... The colonies in general, appear smooth, creamy, and glistening, although some species characteristically produce coarser colonies. ...
Recovering Candida from the urine.
Unlike bacteriuria, however, there is no simply way to decide if funguria is clinically relevant. Neither the absolute colony count nor the presence or absence of white blood cells is consistently helpful.
... the isolation of Candida spp. from the sputum, tracheal aspirates, and even BAL by protected specimen brush is not diagnostic by itself. ...
Serologic Data
... the pace of invasive candidiasis is usually so rapid that serodiagnostic tests don't become positive until the diagnosis is also strongly suggested by other data.
Histopathology
... affected organs will show multiple small abscesses from 1 to 5 mm scattered throughout the parenchyma. Microscopically, the pathologist will find many polymorphonuclear leukocytes forming defined and circumscribed acute abscesses. Intracapillary yeasts (round, 5 to 7 microns) with different grades of budding and formation of pseudohyphae may be seen in acute infection. When the case has progressed to a chronic phase, classic granuloma formation with giant cells are the expected finding. ...
The advent of the glucan synthesis inhibitors may provide the biggest advance yet in therapy of invasive candidiasis. The broad anti-Candida activity of these agents, combined with their low toxicity ....
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Doctor Fungus.org
Biliary Candidiasis
Content Director: Luis Ostrosky-Zeichner, MD.,FACP
Biliary Candidiasis refers to the infection of the gallbladder and/or the biliary tree caused by Candida spp. Even when Candida is isolated from the bile drained during gallbladder surgeries, such recovery is not enough proof that Candida plays a pathogenic role. ...
Candidal cholecystitis presents with such classic biliary symptoms and signs as right quadrant tenderness, intolerance of oral feeding, nausea and vomiting, and fever. Post-cholecystectomy biliary tract obstruction presents also with classic obstructive signs and symptoms of abdominal pain, jaundice, and abdominal distension. ....
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Published in Earth Times, 6 February 2001
Aphrodisiac, Hostettmann, Fungal Infections, Natural Products
Paul Spencer Sochaczewski
Lausanne, Switzerland
Kurt Hostettmann is a world expert on natural aphrodisiacs.
But what really gets him excited is fungus.
Professor Hostettmann, who teaches at the University of Lausanne in Switzerland, has isolated a potent anti-fungal from the root bark of a widely distributed tropical African tree, Bobgunnia madagascariensis.
Traditional healers use the roots of the tree to treat leprosy and
syphilis. The plant's chemicals are said to deter termites. Chemicals
in the fruits effectively kill schistosomiasis-transmitting snails.
And now this multi-purpose plant might give the world a compound
to treat mycosis.
Does the world need a new antifungal?
The new compound, "quinone methide" diterpene, which has received a United States patent, will help the millions of AIDS sufferers who suffer from Candida albicans and Cladosporium cucumerinum fungal infections.
Candida albicans is the widespread fungus that is implicated in vaginal yeast infections; approximately 25% of women without disease symptoms have this organism present, according to the Medical Encyclopedia.
In immuno-compromised individuals, however, Candida may cause life-threatening
illness.
Fungal infections are one of the major causes of death among AIDS patients, Hostettmann explains. "They frequently develop a mycosis in the mouth that often expands into the esophagus, eyes, even the liver."
Medscape notes that "for many [people with AIDS] a Candida fungal infection will be their first HIV-related opportunistic event [and] the first sign of impaired immune function. The severity of the fungal infections increases as the immune system becomes more dysfunctional.
Medscape adds that candidemia is associated with a mortality rate of 50%, with higher mortality likely when the diagnosis of fungal infection is not made early enough to treat the infection. ....
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