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Microsporidia are parasites of animals, now considered to be extremely reduced fungi. Most infect insects, but they are also responsible for common diseases of crustaceans and fish, and have been found in most other animal groups, including humans and other mammals which can be parasitized by species of Encephalitozoon. Replication takes place within the host's cells, which are infected by means of unicellular spores. These vary from 1-40 μm, making them some of the smallest eukaryotes. They also have the shortest eukaryotic genomes. Image File history File links Sporoblast of the Microsporidium Fibrillanosema crangonycis. ...
Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ...
Divisions Chytridiomycota Deuteromycota Zygomycota Glomeromycota Ascomycota Basidiomycota Fungus growing on a tree in Borneo A fungus (plural fungi) is a eukaryotic organism that digests its food externally and absorbs the nutrient molecules into its cells. ...
Zygomycota, or zygote fungi, are a division of fungi. ...
Divisions Chytridiomycota Deuteromycota Zygomycota Glomeromycota Ascomycota Basidiomycota Fungus growing on a tree in Borneo A fungus (plural fungi) is a eukaryotic organism that digests its food externally and absorbs the nutrient molecules into its cells. ...
Classes & Orders See taxonomy Insects are invertebrate animals of the Class Insecta, the largest and (on land) most widely-distributed taxon within the phylum Arthropoda. ...
Classes Remipedia Cephalocarida Branchiopoda Ostracoda Maxillopoda Malacostraca The crustaceans (Crustacea) are a large group of arthropods (55,000 species), usually treated as a subphylum. ...
Atlantic herring, Clupea harengus: the most abundant species of fish in the world. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...
Microsporidia are unusual in lacking mitochondria, and also lack motile structures such as flagella. The spores are protected by a layered wall including proteins and chitin. Their interior is dominated by a unique coiled structure called a polar tube (not to be confused with the polar filaments of Myxozoa). In most cases there are two closely associated nuclei, forming a diplokaryon, but sometimes there is only one. Mitochondria structure : 1) Inner membrane 2) Outer membrane 3) Crista 4) Matrix In cell biology, a mitochondrion (plural mitochondria) (from Greek mitos thread + khondrion granule) is an organelle found in most eukaryotic cells. ...
A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ...
A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...
Structure of chitin molecule In biology, chitin (pronounced keye-tin) is one of the main components in the cell walls of fungi, the exoskeletons of insects and other arthropods, and in some other animals. ...
Classes Malacosporea Myxosporea The Myxozoa are a group of microscopic, parasitic animals. ...
In cell biology, the nucleus (from Latin nucleus or nuculeus, kernel) is found in all eukaryotic cells and contains the nuclear genes which form most of the cells genetic material. ...
During infection, the polar tube penetrates the host cell (the process has been compared by Patrick J. Keeling to "turning a garden hose inside out"), and the contents of the spore are pumped through it. Keeling likens the system to a combination of "harpoon and hypodermic syringe", adding that it is "one of the most sophisticated infection mechanisms in biology". Patrick J. Keeling is a mycologist in the Department of Botany at the University of British Columbia. ...
Whaling harpoon A harpoon is a long spear-like instrument used in fishing to catch fish or other large aquatic animals such as whales. ...
Different bevels on hypodermic needles Syringe on left, hypodermic needle with attached color-coded luer lock on right. ...
Once inside the host cell, the sporoplasm grows, dividing or forming a multinucleate plasmodium before producing new spores. The life cycle varies considerably. Some have a simple asexual life cycle, while others have a complex life cycle involving multiple hosts and both asexual and sexual reproduction. Different types of spores may be produced at different stages, probably with different functions including autoinfection (transmission within a single host). The Microsporidia often cause chronic, debilitating diseases rather than lethal infections. Effects on the host include reduced longevity, fertility, weight, and general vigor. Vertical transmission of microsporidia is frequently reported. This article is about human asexuality; asexual reproduction is a separate topic. ...
Human sexuality is the expression of sexual feelings. ...
Vertical transmission refers to transmission of an infection, such as HIV, hepatitis B, or hepatitis C, from mother to child during the perinatal period, the period immediately before and after birth. ...
Because they are unicellular, Microsporidia were traditionally treated as protozoa, and like other amitochondriate eukaryotes were considered to have diverged very early on. However, other genes place them alongside or within the Fungi, and this is supported by several chemical and morphological features. In particular they appear to be allied with the Zygomycota or Ascomycota. Protozoa (in Greek proto = first and zoa = life) are single-celled eukaryotes (organisms with nuclei) that show some characteristics usually associated with animals, most notably mobility and heterotrophy. ...
Zygomycota, or zygote fungi, are a division of fungi. ...
Classes Archaeascomycetes Discomycetes Euascomycetes Hemiascomycetes Lecanoromycetes Neolectomycetes Pezizomycotina Pneumocystidomycetes Saccharomycotina Schizosaccharomycetes Taphrinomycetes Mitosporic Ascomycota Members of the Division Ascomycota are known as the Sac Fungi and are fungi that produce spores in a distinctive type of microscopic sporangium called an ascus (Greek for a bag or wineskin). This monophyletic grouping...
See also Nosema apis is a microsporidian, a small, unicellular parasite that mainly affects honey bees. ...
References - Patrick J. Keeling et al. (2000). Evidence from Beta-Tubulin Phylogeny that Microsporidia Evolved From Within the Fungi. Molecular Biology and Evolution 17:23-31.
- Nature 414, 401 - 402 (22 November 2001); doi:10.1038/35106666
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