science

Herpesvirales

Herpesvirales 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 Herpesvirales rather than just read about it. In short: Herpesvirales is an order of dsDNA viruses (Baltimore group I) with animal hosts, characterised by a common morphology consisting of an icosahedral capsid enclosed in a glycoprotein-containing lipid envelope. Common infections in humans caused by members of this order include cold sores, genital herpes, chickenpox, shingles, and glandular fever.

Key takeaways

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

Reference excerpt

Herpesvirales is an order of dsDNA viruses (Baltimore group I) with animal hosts, characterised by a common morphology consisting of an icosahedral capsid enclosed in a glycoprotein-containing lipid envelope. Common infections in humans caused by members of this order include cold sores, genital herpes, chickenpox, shingles, and glandular fever. Herpesvirales is the sole order in the class Herviviricetes, which is the sole class in the phylum Peploviricota.

Virology

Morphology All members of the order have a virion structure that consists of a DNA core surrounded by an icosahedral capsid composed of 12 pentavalent and 150 hexavalent capsomeres (T = 16). The capsid has a diameter of ~110 nanometers (nm) and is embedded in a proteinaceous matrix called the tegument, which in its turn is enclosed by a glycoprotein-containing lipid envelope with a diameter of about 200 nm. The DNA genome is linear and double stranded, with sizes in the range 125–290 kbp. The genome contains terminal and internal reiterated sequences, with their number and disposition varying depending on the different subclades.

Hosts

All species in this order have animal hosts. The Malacoherpesviridae infect molluscs (abalone and oysters), the Alloherpesviridae infect anamniotes (frogs and fish), and the Herpesviridae infect amniotes (reptiles, birds, and mammals). Within the family Herpesviridae, genera Iltovirus and Mardivirus, and genus Scutavirus of the subfamily Alphaherpesvirinae infect birds and reptiles, respectively. All other genera in the Herpesviridae infect mammals only.

Taxonomy Herpesvirales contains three families:

Alloherpesviridae Malacoherpesviridae Orthoherpesviridae

History The herpesvirus was first isolated from the blue wildebeest in 1960 by veterinary scientist Walter Plowright. The genus Herpesvirus was established in 1971 in the first report of the International Committee on Taxonomy of Viruses (ICTV). This genus consisted of 23 viruses and 4 groups of viruses. In the second ICTV report in 1976 this genus was elevated to family level - the Herpetoviridae. Because of possible confusion with viruses derived from reptiles this name was changed in the third report in 1979 to Herpesviridae. In this report the family Herpesviridae was divided into 3 subfamilies (Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae) and 5 unnamed genera: 21 viruses were listed. In 2009 the family Herpesviridae was elevated to the order Herpesvirales. This elevation was necessitated by the discovery that the herpesviruses of fish and molluscs were only distantly related to those of birds and mammals. Two new families were created - the family Alloherpesviridae which incorporates bony fish and frog viruses and the family Malacoherpesviridae which contains those of molluscs.

Phylogenetics The only protein with widespread conservation amongst all members of the order, albeit only at the amino-acid level, is the ATPase subunit of the DNA terminase; the latter is involved in the packaging of the DNA during virion assembly. Phylogenies constructed with the conserved regions of the ATPase subunit of the DNA terminase suggest that Alloherpesviridae is the basal clade of the order, and that Herpesviridae and Malacoherpesviridae are sister clades.

References

External links

ICTV Accepted Taxonomic Proposals from the Herpesviridae Study Group (2003–2005) Archived 2020-06-15 at the Wayback Machine

Illustrations

Worked examples

Example 1 — a first encounter with Herpesvirales

Start with the simplest possible case. Write down what Herpesvirales 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 Herpesvirales 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 Herpesvirales 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 Herpesvirales

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

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

Frequently asked questions

What is Herpesvirales in simple terms?

Why does Herpesvirales 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 Herpesvirales?

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 Herpesvirales.