biology

Megavirus

Megavirus is a biology 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 Megavirus rather than just read about it. In short: Megavirus is a viral genus, phylogenetically related to Acanthamoeba polyphaga mimivirus (APMV). In colloquial speech, Megavirus chilense is more commonly referred to as just "Megavirus".

Key takeaways

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

Reference excerpt

Megavirus is a viral genus, phylogenetically related to Acanthamoeba polyphaga mimivirus (APMV). In colloquial speech, Megavirus chilense is more commonly referred to as just "Megavirus". Until the discovery of pandoraviruses in 2013, it had the largest capsid diameter of all known viruses, as well as the largest and most complex genome among all known viruses.

Discovery Megavirus was isolated from a water sample collected in April 2010 off the coast of Chile, near the marine station in Las Cruces, by Jean-Michel Claverie and Chantal Abergel from the Structural & Genomic Information laboratory (IGS, CNRS and Aix-Marseille University). Megavirus was isolated by co-cultivation with a variety of Acanthamoeba laboratory strains (Acanthamoeba polyphaga, Acanthamoeba castellanii, Acanthamoeba griffini) following a protocol pioneered by Timothy Rowbotham for isolating intracellular parasitic bacteria. Megavirus infects amoebas.

Structure The Megavirus particle exhibits a protein capsid diameter of 440 nanometres (as seen by electron microscopy on thin sections of epoxy resin inclusions), enclosed into a solid mesh of bacterial-like capsular material 75 nm to 100 nm thick. The capsid appears hexagonal, but its icosahedral symmetry is imperfect, due to the presence of the "stargate", at a single specific vertex of the icosahedron. The stargate is a five-pronged star structure forming the portal through which the internal core of the particle is delivered to the host's cytoplasm. This core is enclosed within two lipid membranes in the particle, also containing a large and diverse complement of viral proteins (e.g. the all transcriptional complex). Surprisingly, the Megavirus is larger than some bacteria.

Genome The Megavirus chilense genome is a linear, double-stranded molecule of DNA with 1,259,197 base pairs in length. It exhibits 7 aminoacyl tRNA synthetases (Table 2), the archetypes of enzymes previously thought only to be encoded by cellular organisms. While 4 of these enzymes were known to be present in Mimivirus and Mamavirus (for tyrosine, arginine, cysteine, and methionine), Megavirus exhibits three more (for tryptophan, asparagine, and isoleucine).

See also Mimivirus – the giant virus that revolutionized virology Cafeteria roenbergensis virus – the largest marine virus Parvovirus – smallest known single stranded DNA viruses Pithovirus – largest virus by capsid length (approximately 1.5 micrometre) Pandoraviridae – second largest virus by capsid length (approximately 1 micrometre) Virophage

References

External links "GiantVirus.org". www.giantvirus.org. Archived from the original on 14 February 2021. Retrieved 17 August 2024. – an information resource on the genome of giant viruses. Van Etten, James L. (2011). "Giant Viruses". American Scientist. 99 (4): 304. doi:10.1511/2011.91.304.

Illustrations

Worked examples

Example 1 — a first encounter with Megavirus

Start with the simplest possible case. Write down what Megavirus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Megavirus 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 Megavirus 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 Megavirus

In research: Megavirus appears in biology 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 Megavirus 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: Megavirus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Mimiviridae, Virus genera, so understanding it makes those chapters shorter.
In everyday life: Look for Megavirus 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 Megavirus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Megavirus 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 Megavirus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Megavirus in simple terms?

Megavirus is a viral genus, phylogenetically related to Acanthamoeba polyphaga mimivirus (APMV). In colloquial speech, Megavirus chilense is more commonly referred to as just "Megavirus".

Why does Megavirus matter?

Because it connects several biology 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 Megavirus?

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 Megavirus.