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Cellular and Molecular Life Sciences :... Apr 2021Fungal infections are an increasing threat to global public health. There are more than six million fungal species worldwide, but less than 1% are known to infect... (Review)
Review
Fungal infections are an increasing threat to global public health. There are more than six million fungal species worldwide, but less than 1% are known to infect humans. Most of these fungal infections are superficial, affecting the hair, skin and nails, but some species are capable of causing life-threatening diseases. The most common of these include Cryptococcus neoformans, Aspergillus fumigatus and Candida albicans. These fungi are typically innocuous and even constitute a part of the human microbiome, but if these pathogens disseminate throughout the body, they can cause fatal infections which account for more than one million deaths worldwide each year. Thus, systemic dissemination of fungi is a critical step in the development of these deadly infections. In this review, we discuss our current understanding of how fungi disseminate from the initial infection sites to the bloodstream, how immune cells eliminate fungi from circulation and how fungi leave the blood and enter distant organs, highlighting some recent advances and offering some perspectives on future directions.
Topics: Animals; Antifungal Agents; Fungi; Host-Pathogen Interactions; Humans; Mycoses; Virulence
PubMed: 33449153
DOI: 10.1007/s00018-020-03736-z -
Microbiology Spectrum Jun 2017Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and... (Review)
Review
Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and resistance to immune defenses, including elevated body temperatures. Morphogenesis between small round, detachable cells and long, connected cells is the mechanism by which fungi solve problems of locomotion around or through host barriers. Secretion of lytic enzymes, and uptake systems for the released nutrients, are necessary if a fungus is to nutritionally utilize human tissue. Last, the potent human immune system evolved in the interaction with potential fungal pathogens, so few fungi meet all four conditions for a healthy human host. Paradoxically, the advances of modern medicine have made millions of people newly susceptible to fungal infections by disrupting immune defenses. This article explores how different members of four fungal phyla use different strategies to fulfill the four criteria to infect humans: the Entomophthorales, the Mucorales, the Ascomycota, and the Basidiomycota. Unique traits confer human pathogenic potential on various important members of these phyla: pathogenic Onygenales comprising thermal dimorphs such as and ; the spp. that infect immunocompromised as well as healthy humans; and important pathogens of immunocompromised patients-, , and spp. Also discussed are agents of neglected tropical diseases important in global health such as mycetoma and paracoccidiomycosis and common pathogens rarely implicated in serious illness such as dermatophytes. Commensalism is considered, as well as parasitism, in shaping genomes and physiological systems of hosts and fungi during evolution.
Topics: Ascomycota; Basidiomycota; Biological Evolution; Body Temperature; Entomophthorales; Fungi; Host-Pathogen Interactions; Humans; Immunity, Innate; Immunocompromised Host; Mucorales; Mycetoma; Mycoses; Opportunistic Infections; Phylogeny; Virulence
PubMed: 28597822
DOI: 10.1128/microbiolspec.FUNK-0014-2016 -
Molecular Plant Pathology May 2012The aim of this review was to survey all fungal pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate which fungal... (Review)
Review
The aim of this review was to survey all fungal pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate which fungal pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 495 votes from the international community, and resulted in the generation of a Top 10 fungal plant pathogen list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Magnaporthe oryzae; (2) Botrytis cinerea; (3) Puccinia spp.; (4) Fusarium graminearum; (5) Fusarium oxysporum; (6) Blumeria graminis; (7) Mycosphaerella graminicola; (8) Colletotrichum spp.; (9) Ustilago maydis; (10) Melampsora lini, with honourable mentions for fungi just missing out on the Top 10, including Phakopsora pachyrhizi and Rhizoctonia solani. This article presents a short resumé of each fungus in the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant mycology community, as well as laying down a bench-mark. It will be interesting to see in future years how perceptions change and what fungi will comprise any future Top 10.
Topics: Fungi; Plant Pathology; Plants
PubMed: 22471698
DOI: 10.1111/j.1364-3703.2011.00783.x -
Virulence Apr 2017Many species of fungi have been detected in the healthy human gut; however, nearly half of all taxa reported have only been found in one sample or one study. Fungi... (Review)
Review
Many species of fungi have been detected in the healthy human gut; however, nearly half of all taxa reported have only been found in one sample or one study. Fungi capable of growing in and colonizing the gut are limited to a small number of species, mostly Candida yeasts and yeasts in the family Dipodascaceae (Galactomyces, Geotrichum, Saprochaete). Malassezia and the filamentous fungus Cladosporium are potential colonizers; more work is needed to clarify their role. Other commonly-detected fungi come from the diet or environment but either cannot or do not colonize (Penicillium and Debaryomyces species, which are common on fermented foods but cannot grow at human body temperature), while still others have dietary or environmental sources (Saccharomyces cerevisiae, a fermentation agent and sometime probiotic; Aspergillus species, ubiquitous molds) yet are likely to impact gut ecology. The gut mycobiome appears less stable than the bacterial microbiome, and is likely subject to environmental factors.
Topics: Diet; Environmental Exposure; Fungi; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Microbiota; Mycobiome
PubMed: 27736307
DOI: 10.1080/21505594.2016.1247140 -
Microbiology Spectrum Jul 2017The question of how many species of there are has occasioned much speculation, with figures mostly posited from around half a million to 10 million, and in one extreme... (Review)
Review
The question of how many species of there are has occasioned much speculation, with figures mostly posited from around half a million to 10 million, and in one extreme case even a sizable portion of the spectacular number of 1 trillion. Here we examine new evidence from various sources to derive an updated estimate of global fungal diversity. The rates and patterns in the description of new species from the 1750s show no sign of approaching an asymptote and even accelerated in the 2010s after the advent of molecular approaches to species delimitation. Species recognition studies of (semi-)cryptic species hidden in morpho-species complexes suggest a weighted average ratio of about an order of magnitude for the number of species recognized after and before such studies. New evidence also comes from extrapolations of plant:fungus ratios, with information now being generated from environmental sequence studies, including comparisons of molecular and fieldwork data from the same sites. We further draw attention to undescribed species awaiting discovery in biodiversity hot spots in the tropics, little-explored habitats (such as lichen-inhabiting fungi), and material in collections awaiting study. We conclude that the commonly cited estimate of 1.5 million species is conservative and that the actual range is properly estimated at 2.2 to 3.8 million. With 120,000 currently accepted species, it appears that at best just 8%, and in the worst case scenario just 3%, are named so far. Improved estimates hinge particularly on reliable statistical and phylogenetic approaches to analyze the rapidly increasing amount of environmental sequence data.
Topics: Biodiversity; Fungi; History, Ancient; Mycology; Phylogeny; Plants
PubMed: 28752818
DOI: 10.1128/microbiolspec.FUNK-0052-2016 -
Microbiology Spectrum Jan 2017Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures.... (Review)
Review
Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.
Topics: Animals; Fungi; Host-Pathogen Interactions; Nematoda
PubMed: 28128072
DOI: 10.1128/microbiolspec.FUNK-0022-2016 -
Current Biology : CB Dec 2021Fungi are key organisms of the biosphere with major roles in organic-matter decomposition, element cycling, plant pathogenicity, and symbioses in aquatic and terrestrial...
Fungi are key organisms of the biosphere with major roles in organic-matter decomposition, element cycling, plant pathogenicity, and symbioses in aquatic and terrestrial habitats. The vast majority exhibit a filamentous, branching growth form and are aerobic chemoorganotrophs that derive carbon and energy from organic substances, and are particularly associated with soil, the plant-root zone, and rock surfaces. It is now known that some fungi are lithotrophs, deriving energy from the oxidation of inorganic materials, whereas others are photoheterotrophs, deriving additional energy from light for organic matter utilization when oxygen is limited. This means that fungi are of much wider environmental significance than previously thought and explains their ubiquity in locations previously thought to be inimical to fungal existence, such as the deep subsurface and other anaerobic locations. In addition to such free-living species, fungi associated with photosynthetic partners are also of profound biosphere importance. For example, lichens, which are composed of a symbiotic association between a fungus and a phototrophic alga and/or cyanobacterium, are pioneer colonizers and bioweathering agents of rocks and minerals. Mycorrhizas are symbiotic, plant-root-associated fungi found to colonize the majority of plant genera, where they improve plant nutrition through solubilization of essential metals and phosphate from soil minerals. Biomineralization in the soil can also immobilize toxic metals in the vicinity of plant roots, thereby benefiting plant colonization and facilitating revegetation of contaminated habitats. Wherever fungi are found, transformation of metals and minerals is a key aspect of their activity, with biomineralization an important feature. Fungal biomineralization is an important facet of geomycology - namely the roles of fungi in geochemical and geophysical processes. This article seeks to highlight the concept of biomineralization as applied to fungi, the occurrence and significance of important fungal biominerals in natural and synthetic environments, and the applied potential of fungal biomineralization in nanobiotechnology.
Topics: Biomineralization; Fungi; Metals; Minerals; Mycorrhizae; Plant Roots; Plants; Soil; Soil Microbiology
PubMed: 34932960
DOI: 10.1016/j.cub.2021.10.041 -
Insect Biochemistry and Molecular... Aug 2019The mosquito immune system has evolved in the presence of continuous encounters with fungi that range from food to foes. Herein, we review the field of mosquito-fungal... (Review)
Review
The mosquito immune system has evolved in the presence of continuous encounters with fungi that range from food to foes. Herein, we review the field of mosquito-fungal interactions, providing an overview of current knowledge and topics of interest. Mosquitoes encounter fungi in their aquatic and terrestrial habitats. Mosquito larvae are exposed to fungi on plant detritus, within the water column, and at the water surface. Adult mosquitoes are exposed to fungi during indoor and outdoor resting, blood and sugar feeding, mating, and oviposition. Fungi enter the mosquito body through different routes, including ingestion and through active or passive breaches in the cuticle. Oral uptake of fungi can be beneficial to mosquitoes, as yeasts hold nutritional value and support larval development. However, ingestion of or surface contact with fungal entomopathogens leads to colonization of the mosquito with often lethal consequences to the host. The mosquito immune system recognizes fungi and mounts cellular and humoral immune responses in the hemocoel, and possibly epithelial immune responses in the gut. These responses are regulated transcriptionally through multiple signal transduction pathways. Proteolytic protease cascades provide additional regulation of antifungal immunity. Together, these immune responses provide an efficient barrier to fungal infections, which need to be overcome by entomopathogens. Therefore, fungi constitute an excellent tool to examine the molecular underpinnings of mosquito immunity and to identify novel antifungal peptides. In addition, recent advances in mycobiome analyses can now be used to examine the contribution of fungi to various mosquito traits, including vector competence.
Topics: Animals; Culicidae; Ecosystem; Fungi; Host-Pathogen Interactions; Mycobiome
PubMed: 31265904
DOI: 10.1016/j.ibmb.2019.103182 -
Nature Communications Dec 2018Diagnosing fungal infections poses a number of unique problems, including a decline in expertise needed for identifying fungi, and a reduced number of instruments and... (Review)
Review
Diagnosing fungal infections poses a number of unique problems, including a decline in expertise needed for identifying fungi, and a reduced number of instruments and assays specific for fungal identification compared to that of bacteria and viruses.These problems are exacerbated by the fact that patients with fungal infections are often immunosuppressed, which predisposes to infections from both commonly and rarely seen fungi. In this review, we discuss current and future molecular technologies used for fungal identification, and some of the problems associated with development and implementation of these technologies in today's clinical microbiology laboratories.
Topics: DNA, Fungal; Fungi; Humans; Molecular Diagnostic Techniques; Mycoses; Polymerase Chain Reaction; Reproducibility of Results; Sensitivity and Specificity; Sequence Analysis, DNA
PubMed: 30510235
DOI: 10.1038/s41467-018-07556-5 -
Microbiology Spectrum Jun 2017Fungi and insects live together in the same habitats, and many species of both groups rely on each other for success. Insects, the most successful animals on Earth,... (Review)
Review
Fungi and insects live together in the same habitats, and many species of both groups rely on each other for success. Insects, the most successful animals on Earth, cannot produce sterols, essential vitamins, and many enzymes; fungi, often yeast-like in growth form, make up for these deficits. Fungi, however, require constantly replenished substrates because they consume the previous ones, and insects, sometimes lured by volatile fungal compounds, carry fungi directly to a similar, but fresh, habitat. Yeasts associated with insects include Ascomycota (Saccharomycotina, Pezizomycotina) and a few Basidiomycota. Beetles, homopterans, and flies are important associates of fungi, and in turn the insects carry yeasts in pits, specialized external pouches, and modified gut pockets. Some yeasts undergo sexual reproduction within the insect gut, where the genetic diversity of the population is increased, while others, well suited to their stable environment, may never mate. The range of interactions extends from dispersal of yeasts on the surface of insects (e.g., cactus--yeast and ephemeral flower communities, ambrosia beetles, yeasts with holdfasts) to extremely specialized associations of organisms that can no longer exist independently, as in the case of yeast-like symbionts of planthoppers. In a few cases yeast-like fungus-insect associations threaten butterflies and other species with extinction. Technical advances improve discovery and identification of the fungi but also inform our understanding of the evolution of yeast-insect symbioses, although there is much more to learn.
Topics: Adaptation, Physiological; Animals; Ascomycota; Basidiomycota; Biological Evolution; Gastrointestinal Microbiome; Insecta; Phylogeny; Symbiosis; Yeasts
PubMed: 28597823
DOI: 10.1128/microbiolspec.FUNK-0081-2016