science

Labyrinthulomycetes

Labyrinthulomycetes is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Labyrinthulomycetes rather than just read about it. In short: Labyrinthulomycetes (ICNafp) or Labyrinthulea (ICZN) is a class of protists that produce a network of filaments or tubes, which serve as tracks for the cells to glide along and absorb nutrients for them. The two main groups are the labyrinthulids (or slime nets) and thraustochytrids.

Key takeaways

Labyrinthulomycetes belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Labyrinthulomycetes to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Labyrinthulomycetes from memory before moving on to harder problems.

Reference excerpt

Labyrinthulomycetes (ICNafp) or Labyrinthulea (ICZN) is a class of protists that produce a network of filaments or tubes, which serve as tracks for the cells to glide along and absorb nutrients for them. The two main groups are the labyrinthulids (or slime nets) and thraustochytrids. They are mostly marine, commonly found as parasites on algae and seagrasses or as decomposers on dead plant material. They also include some parasites of marine invertebrates and mixotrophic species that live in a symbiotic relationship with zoochlorella.

Characteristics Although they are outside the cells, the filaments of Labyrinthulomycetes are surrounded by a membrane. They are formed and connected with the cytoplasm by a unique organelle called a sagenogen or bothrosome. The cells are uninucleated and typically ovoid, and move back and forth along the amorphous network at speeds varying from 5-150 μm per minute. Among the labyrinthulids, the cells are enclosed within the tubes, and among the thraustochytrids, they are attached to their sides.

Evolution

Evolutionary origin Labyrinthulomycetes are not fungi, but a monophyletic group of eukaryotes within the Stramenopiles. They belong to the phylum Bigyra, which contains other heterotrophic microorganisms such as the bicosoecids. Considering that the plastids from Stramenopiles are possibly the result of an event of endosymbiosis in their last common ancestor, the bicosoecids and the labyrinthulomycetes could have originated from a mixotrophic algal common ancestor that secondarily lost their plastids. Some characteristics of the labyrinthulomycetes can be explained by their origin from ancestral plastids. They produce omega-3 poly-unsaturated fatty acids using a desaturase usually present in chloroplasts. The zoospores of labyrinthulids have an eyespot composed of membrane-bound granules that resembles eyespots of photosynthetic stramenopiles, which are either within a plastid or believed to be derived from a plastid. Within Bigyra, the labyrinthulomycetes are the sister group to Eogyrea, a class containing the species Pseudophyllomitus vesiculosus and the environmental clade called MAST-4. Together they compose the subphylum Sagenista.

Classification Labyrinthulomycetes or Labyrinthulea used to compose the defunct fungal phylum Labyrinthulomycota. They were originally considered unusual slime moulds, although they are not very similar to the other sorts. The structure of their zoospores and genetic studies show them to be a primitive group of heterokonts, but their classification and treatment remains somewhat unsettled. This class usually contained two orders, Labyrinthulales and Thraustochytriales (ICBN), or Labyrinthulida and Thraustochytrida (ICZN), but a different classification has recently been proposed.

Order Labyrinthulales/Labyrinthulida E. A. Bessey 1950/Doffein 1901 Family Aplanochytriaceae/Aplanochytriidae Leander ex Cavalier-Smith 2012 Aplanochytrium Bahnweg & Sparrow 1972 [=Labyrinthuloides Perkins 1973] Family Labyrinthulaceae/Labyrinthulidae Haeckel 1868/Cinekowksa 1867 Labyrinthomyxa Duboscq 1921 Pseudoplasmodium Molisch 1925 Labyrinthula Cienkowski 1864 [=Labyrinthodictyon Valkanov 1969; Labyrinthorhiza Chadefaud 1956] Family-level clade "Stellarchytriaceae/Stellarchytriidae" – this group is provisionally placed in Labyrinthulida but, according to phylogenetic analyses, diverges before the rest of labyrinthulean clades. Stellarchytrium FioRito & Leander 2016 Order Oblongichytriales/Oblongichytrida Family Oblongichytriaceae/Oblongichytriidae Cavalier-Smith 2012 Oblongichytrium Yokoyama & Honda 2007 Order Thraustochytriales/Thraustochytrida Sparrow 1973 Pyrrhosorus Juel 1901 Thanatostrea Franc & Arvy 1969 Family Althornidiaceae/Althorniidae Jones & Alderman 1972 Althornia Jones & Alderman 1972 Family Thraustochytriacae/Thraustochytriidae Sparrow ex Cejp 1959 Japanochytrium Kobayasi & Ôkubo 1953 Monorhizochytrium Doi & Honda 2017 Sicyoidochytrium Yokoy., Salleh & Honda 2007 Aurantiochytrium Yokoy. & Honda 2007 Ulkenia Gaertn. 1977 Parietichytrium Yokoy., Salleh & Honda 2007 Botryochytrium Yokoy., Salleh & Honda 2007 Schizochytrium Goldst. & Belsky emend. Booth & Mill. Thraustochytrium Sparrow 1936 Hondaea Amato & Cagnac 2018 Labyrinthulochytrium Hassett & Gradinger 2018 Order Amphitrematales/Amphitremida Gomaa et al. 2013 Family "Amphitremidiaceae"/Amphitremidae Poch 1913 Paramphitrema Valkanov 1970 Archerella Loeblich & Tappan 1961 Amphitrema Archer 1867 Family "Diplophrydaceae"/Diplophryidae Cavalier-Smith 2012 Diplophrys Barker 1868 Order "Amphifilales"/Amphifilida Cavalier Smith 2012 Family Sorodiplophryidae Cavalier-Smith 2012 Sorodiplophrys Olive & Dykstra 1975 Fibrophrys Takahashi et al. 2016 Family Amphifilidae Cavalier-Smith 2012 Genus Amphifila Cavalier-Smith 2012

Genetic code The labyrinthulomycete Thraustochytrium aureum is notable for the alternative genetic code of its mitochondria which use TTA as a stop codon instead of coding for Leucine. This code is represented by NCBI translation table 23, Thraustochytrium mitochondrial code.

Gallery

References

External links

Labyrinthulomycota

Illustrations

Worked examples

Example 1 — a first encounter with Labyrinthulomycetes

Start with the simplest possible case. Write down what Labyrinthulomycetes claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Labyrinthulomycetes before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Labyrinthulomycetes ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Labyrinthulomycetes

In research: Labyrinthulomycetes appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Labyrinthulomycetes in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Labyrinthulomycetes is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bigyra, Stramenopile classes, so understanding it makes those chapters shorter.
In everyday life: Look for Labyrinthulomycetes outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Labyrinthulomycetes in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Labyrinthulomycetes means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Labyrinthulomycetes out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Labyrinthulomycetes in simple terms?

Why does Labyrinthulomycetes matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Labyrinthulomycetes?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Labyrinthulomycetes.