science

Cystovirus

Cystovirus 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 Cystovirus rather than just read about it. In short: Cystoviruses are a family of double-stranded RNA viruses that infect bacteria. They constitute the family Cystoviridae.

Key takeaways

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

Reference excerpt

Cystoviruses are a family of double-stranded RNA viruses that infect bacteria. They constitute the family Cystoviridae. The name of the group cysto derives from Greek kystis which means bladder or sack. There are seven genera in this family.

Discovery Pseudomonas virus phi6 was the first virus in this family to be discovered and was initially characterized in 1973 by Anne Vidaver at the University of Nebraska–Lincoln. She found that when she cultured the bacterial strain Pseudomonas phaseolicola HB1OY with halo blight infected bean straw, cytopathic effects were detected in cultured lawns, indicating that there was a lytic microbe or bacteriophage present. In 1999, phi7–14 were identified by the laboratory of Leonard Mindich at the Public Health Research Institute associated with New York University. They did this by culturing various leaves in Lysogeny Broth and then plating the broth on lawns of Pseudomonas syringae pv phaseolicola. They were able to identify viral plaques from this and then subsequently sequence their genomes.

Microbiology

Structure

Cystovirus particles are enveloped, with icosahedral and spherical geometries, and T=13, T=2 symmetry. The virion diameter is around 85 nm.

Genome Cystoviruses have a tripartite double-stranded RNA genome which is approximately 14 kbp in total length. The genome is linear and segmented, and labeled as large (L) 6.4 kbp, medium (M) 4 kbp, and small (S) 2.9 kb in length. The genome codes for twelve proteins.

Life cycle

Cystoviruses enter the bacteria by adsorption on its pilus and then membrane fusion. Viral replication is cytoplasmic. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. The progeny viruses are released from the cell by lysis. Most identified cystoviruses infect Pseudomonas species, but this is likely biased due to the method of screening and enrichment. There are many proposed members of this family. Pseudomonas viruses φ7, φ8, φ9, φ10, φ11, φ12, and φ13 have been identified and named, but other cystovirus-like viruses have also been isolated. These seven putative relatives are classified as either close (φ7, φ9, φ10, φ11) or distant (φ8, φ12, φ13) relatives to φ6, with the distant relatives thought to infect via the LPS rather than the pili. However, cystoviruses do not only infect Pseudomonas. But also bacteria of the genera Streptomyces, Microvirgula, Acinetobacter, Lactococcus, Pectobacterium, and possibly other bacterial genera.

Taxonomy

The family contains the following genera and species (-virus denotes genus):

Other unassigned phages:

Streptomyces virus phi0 Lactococcus virus phi7-4 Pectobacterium virus MA14 Acinetobacter virus CAP3 Acinetobacter virus CAP4 Acinetobacter virus CAP5 Acinetobacter virus CAP6 Acinetobacter virus CAP7

References

External links ICTV Online Report: Cystoviridae Viralzone: Cystovirus

Illustrations

Worked examples

Example 1 — a first encounter with Cystovirus

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

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

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

Frequently asked questions

What is Cystovirus in simple terms?

Cystoviruses are a family of double-stranded RNA viruses that infect bacteria. They constitute the family Cystoviridae.

Why does Cystovirus 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 Cystovirus?

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 Cystovirus.