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Tetraploa aristata is the most frequently found fungal species in the family Massarinaceae. It is a water-borne fungus. It represents the anamorphic stage of numbers of pleomorphic hyphomycetes which can alter their morphologies in response to different environments and stresses.

History
This fungus is discovered by British mycologists Berkeley and Broome in 1850. T. aristata was first collected and identified from grass collected at Westhay Woods, King's Cliffe, Northants. It may have existed since the Neogene period. It is found to be associated with fossil pollen grains of Graminidites bambusodies, which is a bamboo species from the Neogene period around Poland, Europe. From the relationship between G. bambusodies and T. aristata, it has been suggested that there should be a warm temperate climate in Poland and its nearby region in the Neogene period because T. aristata tends to live in places with temperate climate.

Habitat
T. aristata is wildly distributed in subtropical and tropical regions. It is found almost exclusively in countries with mild climate, such as Java (an island in Indonesia), Belgium, Denmark, Germany, Italy, United States, Argentina, etc..

It grows throughout the year. It commonly lives on grasses, corns, sedges, monocotyledon and a variety of plants (recorded on more than 120 species). It tends to populate on the bases of leaves and stems that are just above the soil line.

It has also been found on decaying wood and leaves.

Ecology
It is recorded that T. aristata is parasitic to plants. It was recognized as saprophyte in many plants, such as Syzygium, Cenchrus, dead stalks of Elegia capensis, etc.. It is speculated that T. aristata may lead their hosts to death in order to obtain nutrients from the dead matters.

It is also found as endophytic microorganism in Opuntia ficus-indica (cactus) in Brazil. It is mutualistic to cactus because it is a good producer of proteases. While the fungus utilizes the proteases to overcome the plant's defenses to its invasion, the plants can use the proteases synthesized by the fungus to obtain nutrients from the soil.

Morphology
T. aristata has an unique fruiting body that is distinct to the other fungi. On the top of the fruiting body, there are four septate hyphae. T. aristata does not have conidiophores but the conidia directly bud off from the hyphae near the tips. The morphological characteristic of T. aristata will be described in three parts: Ascomata (the fruiting body), hyphae, and conidia. The morphology described above is the T. aristata that discovered by Berkeley and Broome, which the hyphae are about the same length as the fruiting body. However, Mycologist M.B. Ellis found that there is another kind of T. aristata which has a much smaller fruiting body with very long hyphae.
 * Ascomata (the fruiting body) has a shape similar to an inverted egg with the narrow side on the bottom. The body size is about 25-40 X 14-28 μm. The surface is brown and warty. It looks like a combination of four columns of cells sticking together. Each columns usually have four cells with diameter of 9-16 μm.
 * Hyphae, or appendages, have pale brown and smooth surface. A hypha contain septa which decrease in thickness as growing further from the fruiting body; the septum is the thinnest near the tip. It is usually about 10-90 μm long. The diameter of hypha can be up to 8 μm near the fruiting body and narrow down to 2-3.5 μm at the apex. It is not in rigid state. It can bend or curve in all direction easily.
 * Conidia bud off from hyphae. A conidium is single-cell, short and cylindrical. It is monoblastic which means for each around of reproduction, there is only one conidium produced from the conidiogenous cells on the hypha. The conidia leave the hyphae when they develop into four-cells stage.

Growth
The samples collected during Spring time are mostly young and developing spores; whereas the predominated mature spores are mostly found in the late Summer, Autumn and Winter. The colonies of T. aristata are either localized on a specific location on the plants or they spread around the stem forming an irregular mat which is about 4-5 cm long. The colonies varies from dark grey-brown to dark brown colour.

The conidium develops by budding off from the mycelium while carrying cell contents and one nucleus along with it. The bud swells and divides into two cells by developing a vertical wall in between. The two cells divides again by developing a second vertical wall that is about 90° away from the first vertical wall. Then, the four cells all swells and elongates in a vertical direction independently. While the cells are elongating, the cell contents within each cell are also being stretched, which form furrow in each column. The elongated cells divide by horizontal walls forming a column of 2-6 cells. In mature spores, the furrows in each column keep elongating and growing as appendages out of the body independently. The appendages tend to diverge from one another apically.

Mycologist Ellis also observed that there are pores in the septa that allow the sharing of cell contents, such as ions, proteins, amino acid, nucleotides, etc., throughout the whole fungus.

Physiology
A strain CLPS 419 of T. aristata collected from Argentina is able to produce high level of extracellular laccase activity. Laccase is an oxidative enzyme found in many plants, fungi and microorganisms. When T. aristata is artificially supplied with glucose or sucrose in shaking cultures, it has efficient production of laccase. But the production level drops when it is in stationary cultures. Researchers suggest that the production level may be affected by the difference in the oxygen availability; T. aristata can access to more oxygen in the shaking culture. This indicates that T. aristata may utilize aerobic process for laccase production. However, there is no development of conidia shown when strain CLPS 419 is tested in the laboratory.

A strain of T. aristata found in Opuntia ficus-indica in Brazil also showed potential to product xylanase, which is a hydrolytic enzyme that cleaves the beta-1,4 backbone of plant cell wall.

Spore dispersal
The structure of T. aristata resembles the ones of some aquatic hyphomycetes. When a thin layer of water is placed over an T. aristata-infected leaf, the conidia break off from the hyphae and flow to the water surface. The conidia also flow along with the water when the leaf is tilted. Therefore, it is suggested that water, especially flowing water, aids in T. aristata dispersal similarly to the other aquatic hyphomycetes. Many samples of T. aristata are collected from plants that are near the water or often experience period flooding. This consolidates that T. aristata is a water-borne fungus.

Besides, T. aristata may also utilize wind to disperse the spores. In some warm regions of the world, such as Taiwan, Mexico, India, etc., T. aristata spores have been identified within the samples collected from the air along with other fungal spores. This may be the way they can populate into mainlands where have little access to the sea or the rivers.

Human pathogenicity
T. aristata is dematiaceous fungus which causes infection in the deep dermis and subcutaneous tissues. For example, it has caused Phaeohyphomycotic cyst in human before. A 54-years-old white man has been diagnosed with Phaeohyphomycotic cyst in a hospital in Dothan, Alabama. The cyst formed a large mass on the patient's left knee. X-ray exmaination showed focal calcification in the inferior of the cyst. After dissection of the cyst, it is found that the cyst has a thick and fibrous cell walls and contains a thick-texture and tan-gray fluid. Staining the cyst tissue with hematoxylin and eosin showed many septate and hyphal elements that resemble the structure of T. aristata. The patient recovered after the removal of the cyst.

Beside Phaeohyphomycotic cyst, T. aristata has also been reported causing keratomycosis in the United States and Argentina. But it may be mistaken with another species within the genus Tetraploa. It has also been reported causing respiratory infections, such as sinusitis, pneumonia, etc..